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* [PATCH 0/2] mips: convert to generic entry
@ 2021-09-07  6:16 FreeFlyingSheep
  2021-09-07  6:16 ` [PATCH 1/2] mips: convert syscall " FreeFlyingSheep
  2021-09-07  6:16 ` [PATCH 2/2] mips: convert irq " FreeFlyingSheep
  0 siblings, 2 replies; 15+ messages in thread
From: FreeFlyingSheep @ 2021-09-07  6:16 UTC (permalink / raw)
  To: tsbogend, tglx, peterz, luto, arnd
  Cc: Feiyang Chen, linux-mips, linux-arch, chenhuacai, jiaxun.yang,
	chris.chenfeiyang

From: Feiyang Chen <chenfeiyang@loongson.cn>

Convert mips to use the generic entry infrastructure from
kernel/entry/*.

Feiyang Chen (2):
  mips: convert syscall to generic entry
  mips: convert irq to generic entry

 arch/mips/Kconfig                         |   1 +
 arch/mips/include/asm/entry-common.h      |  13 ++
 arch/mips/include/asm/irqflags.h          |  42 ----
 arch/mips/include/asm/ptrace.h            |   8 +-
 arch/mips/include/asm/sim.h               |  70 -------
 arch/mips/include/asm/stackframe.h        |   8 +
 arch/mips/include/asm/syscall.h           |   5 +
 arch/mips/include/asm/thread_info.h       |  17 +-
 arch/mips/include/uapi/asm/ptrace.h       |   7 +-
 arch/mips/kernel/Makefile                 |  14 +-
 arch/mips/kernel/entry.S                  | 143 +-------------
 arch/mips/kernel/genex.S                  | 148 +++-----------
 arch/mips/kernel/head.S                   |   1 -
 arch/mips/kernel/linux32.c                |   1 -
 arch/mips/kernel/ptrace.c                 |  78 --------
 arch/mips/kernel/r4k-bugs64.c             |  14 +-
 arch/mips/kernel/scall.S                  | 130 +++++++++++++
 arch/mips/kernel/scall32-o32.S            | 223 ----------------------
 arch/mips/kernel/scall64-n32.S            | 107 -----------
 arch/mips/kernel/scall64-n64.S            | 116 -----------
 arch/mips/kernel/scall64-o32.S            | 221 ---------------------
 arch/mips/kernel/signal.c                 |  59 +-----
 arch/mips/kernel/signal_n32.c             |  15 +-
 arch/mips/kernel/signal_o32.c             |  29 +--
 arch/mips/kernel/syscall.c                | 147 +++++++++++---
 arch/mips/kernel/syscalls/syscall_n32.tbl |   8 +-
 arch/mips/kernel/syscalls/syscall_n64.tbl |   8 +-
 arch/mips/kernel/syscalls/syscall_o32.tbl |   8 +-
 arch/mips/kernel/traps.c                  | 202 ++++++++++++++------
 arch/mips/kernel/unaligned.c              |  19 +-
 arch/mips/mm/c-octeon.c                   |  15 ++
 arch/mips/mm/cex-oct.S                    |   8 +-
 arch/mips/mm/fault.c                      |  12 +-
 arch/mips/mm/tlbex-fault.S                |   7 +-
 34 files changed, 562 insertions(+), 1342 deletions(-)
 create mode 100644 arch/mips/include/asm/entry-common.h
 delete mode 100644 arch/mips/include/asm/sim.h
 create mode 100644 arch/mips/kernel/scall.S
 delete mode 100644 arch/mips/kernel/scall32-o32.S
 delete mode 100644 arch/mips/kernel/scall64-n32.S
 delete mode 100644 arch/mips/kernel/scall64-n64.S
 delete mode 100644 arch/mips/kernel/scall64-o32.S

-- 
2.27.0


^ permalink raw reply	[flat|nested] 15+ messages in thread

* [PATCH 1/2] mips: convert syscall to generic entry
  2021-09-07  6:16 [PATCH 0/2] mips: convert to generic entry FreeFlyingSheep
@ 2021-09-07  6:16 ` FreeFlyingSheep
  2021-09-07 13:48   ` Jiaxun Yang
  2021-09-07  6:16 ` [PATCH 2/2] mips: convert irq " FreeFlyingSheep
  1 sibling, 1 reply; 15+ messages in thread
From: FreeFlyingSheep @ 2021-09-07  6:16 UTC (permalink / raw)
  To: tsbogend, tglx, peterz, luto, arnd
  Cc: Feiyang Chen, linux-mips, linux-arch, chenhuacai, jiaxun.yang,
	chris.chenfeiyang, Yanteng Si

From: Feiyang Chen <chenfeiyang@loongson.cn>

Convert mips syscall to use the generic entry infrastructure from
kernel/entry/*.

There are a few special things on mips:

- There is one type of syscall on mips32 (scall32-o32) and three types
of syscalls on mips64 (scall64-o32, scall64-n32 and scall64-n64). Now
convert to C code to handle different types of syscalls.

- For some special syscalls (e.g. fork, clone, clone3 and sysmips),
save_static_function() wrapper is used to save static registers. Now
SAVE_STATIC is used in handle_sys before calling do_syscall(), so the
save_static_function() wrapper can be removed.

- For sigreturn/rt_sigreturn and sysmips, inline assembly is used to
jump to syscall_exit directly for skipping setting the error flag and
restoring all registers. Now use regs->regs[27] to mark whether to
handle the error flag and always restore all registers in handle_sys,
so these functions can return normally as other architecture.

Signed-off-by: Feiyang Chen <chenfeiyang@loongson.cn>
Signed-off-by: Yanteng Si <siyanteng@loongson.cn>
---
 arch/mips/Kconfig                         |   1 +
 arch/mips/include/asm/entry-common.h      |  13 ++
 arch/mips/include/asm/ptrace.h            |   8 +-
 arch/mips/include/asm/sim.h               |  70 -------
 arch/mips/include/asm/syscall.h           |   5 +
 arch/mips/include/asm/thread_info.h       |  17 +-
 arch/mips/include/uapi/asm/ptrace.h       |   7 +-
 arch/mips/kernel/Makefile                 |  14 +-
 arch/mips/kernel/entry.S                  |  75 ++------
 arch/mips/kernel/linux32.c                |   1 -
 arch/mips/kernel/ptrace.c                 |  78 --------
 arch/mips/kernel/scall.S                  | 135 +++++++++++++
 arch/mips/kernel/scall32-o32.S            | 223 ----------------------
 arch/mips/kernel/scall64-n32.S            | 107 -----------
 arch/mips/kernel/scall64-n64.S            | 116 -----------
 arch/mips/kernel/scall64-o32.S            | 221 ---------------------
 arch/mips/kernel/signal.c                 |  35 ++--
 arch/mips/kernel/signal_n32.c             |  15 +-
 arch/mips/kernel/signal_o32.c             |  29 +--
 arch/mips/kernel/syscall.c                | 147 +++++++++++---
 arch/mips/kernel/syscalls/syscall_n32.tbl |   8 +-
 arch/mips/kernel/syscalls/syscall_n64.tbl |   8 +-
 arch/mips/kernel/syscalls/syscall_o32.tbl |   8 +-
 23 files changed, 346 insertions(+), 995 deletions(-)
 create mode 100644 arch/mips/include/asm/entry-common.h
 delete mode 100644 arch/mips/include/asm/sim.h
 create mode 100644 arch/mips/kernel/scall.S
 delete mode 100644 arch/mips/kernel/scall32-o32.S
 delete mode 100644 arch/mips/kernel/scall64-n32.S
 delete mode 100644 arch/mips/kernel/scall64-n64.S
 delete mode 100644 arch/mips/kernel/scall64-o32.S

diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index 0cf31a6cbee1..61aa125aa2da 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -32,6 +32,7 @@ config MIPS
 	select GENERIC_ATOMIC64 if !64BIT
 	select GENERIC_CMOS_UPDATE
 	select GENERIC_CPU_AUTOPROBE
+	select GENERIC_ENTRY
 	select GENERIC_GETTIMEOFDAY
 	select GENERIC_IOMAP
 	select GENERIC_IRQ_PROBE
diff --git a/arch/mips/include/asm/entry-common.h b/arch/mips/include/asm/entry-common.h
new file mode 100644
index 000000000000..0fe2a098ded9
--- /dev/null
+++ b/arch/mips/include/asm/entry-common.h
@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef ARCH_LOONGARCH_ENTRY_COMMON_H
+#define ARCH_LOONGARCH_ENTRY_COMMON_H
+
+#include <linux/sched.h>
+#include <linux/processor.h>
+
+static inline bool on_thread_stack(void)
+{
+	return !(((unsigned long)(current->stack) ^ current_stack_pointer) & ~(THREAD_SIZE - 1));
+}
+
+#endif
diff --git a/arch/mips/include/asm/ptrace.h b/arch/mips/include/asm/ptrace.h
index daf3cf244ea9..1b8f9d2ddc44 100644
--- a/arch/mips/include/asm/ptrace.h
+++ b/arch/mips/include/asm/ptrace.h
@@ -51,6 +51,11 @@ struct pt_regs {
 	unsigned long __last[0];
 } __aligned(8);
 
+static inline int regs_irqs_disabled(struct pt_regs *regs)
+{
+	return arch_irqs_disabled_flags(regs->cp0_status);
+}
+
 static inline unsigned long kernel_stack_pointer(struct pt_regs *regs)
 {
 	return regs->regs[29];
@@ -156,9 +161,6 @@ static inline long regs_return_value(struct pt_regs *regs)
 #define instruction_pointer(regs) ((regs)->cp0_epc)
 #define profile_pc(regs) instruction_pointer(regs)
 
-extern asmlinkage long syscall_trace_enter(struct pt_regs *regs, long syscall);
-extern asmlinkage void syscall_trace_leave(struct pt_regs *regs);
-
 extern void die(const char *, struct pt_regs *) __noreturn;
 
 static inline void die_if_kernel(const char *str, struct pt_regs *regs)
diff --git a/arch/mips/include/asm/sim.h b/arch/mips/include/asm/sim.h
deleted file mode 100644
index 59f31a95facd..000000000000
--- a/arch/mips/include/asm/sim.h
+++ /dev/null
@@ -1,70 +0,0 @@
-/*
- * This file is subject to the terms and conditions of the GNU General Public
- * License.  See the file "COPYING" in the main directory of this archive
- * for more details.
- *
- * Copyright (C) 1999, 2000, 2003 Ralf Baechle
- * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
- */
-#ifndef _ASM_SIM_H
-#define _ASM_SIM_H
-
-
-#include <asm/asm-offsets.h>
-
-#define __str2(x) #x
-#define __str(x) __str2(x)
-
-#ifdef CONFIG_32BIT
-
-#define save_static_function(symbol)					\
-__asm__(								\
-	".text\n\t"							\
-	".globl\t__" #symbol "\n\t"					\
-	".align\t2\n\t"							\
-	".type\t__" #symbol ", @function\n\t"				\
-	".ent\t__" #symbol ", 0\n__"					\
-	#symbol":\n\t"							\
-	".frame\t$29, 0, $31\n\t"					\
-	"sw\t$16,"__str(PT_R16)"($29)\t\t\t# save_static_function\n\t"	\
-	"sw\t$17,"__str(PT_R17)"($29)\n\t"				\
-	"sw\t$18,"__str(PT_R18)"($29)\n\t"				\
-	"sw\t$19,"__str(PT_R19)"($29)\n\t"				\
-	"sw\t$20,"__str(PT_R20)"($29)\n\t"				\
-	"sw\t$21,"__str(PT_R21)"($29)\n\t"				\
-	"sw\t$22,"__str(PT_R22)"($29)\n\t"				\
-	"sw\t$23,"__str(PT_R23)"($29)\n\t"				\
-	"sw\t$30,"__str(PT_R30)"($29)\n\t"				\
-	"j\t" #symbol "\n\t"						\
-	".end\t__" #symbol "\n\t"					\
-	".size\t__" #symbol",. - __" #symbol)
-
-#endif /* CONFIG_32BIT */
-
-#ifdef CONFIG_64BIT
-
-#define save_static_function(symbol)					\
-__asm__(								\
-	".text\n\t"							\
-	".globl\t__" #symbol "\n\t"					\
-	".align\t2\n\t"							\
-	".type\t__" #symbol ", @function\n\t"				\
-	".ent\t__" #symbol ", 0\n__"					\
-	#symbol":\n\t"							\
-	".frame\t$29, 0, $31\n\t"					\
-	"sd\t$16,"__str(PT_R16)"($29)\t\t\t# save_static_function\n\t"	\
-	"sd\t$17,"__str(PT_R17)"($29)\n\t"				\
-	"sd\t$18,"__str(PT_R18)"($29)\n\t"				\
-	"sd\t$19,"__str(PT_R19)"($29)\n\t"				\
-	"sd\t$20,"__str(PT_R20)"($29)\n\t"				\
-	"sd\t$21,"__str(PT_R21)"($29)\n\t"				\
-	"sd\t$22,"__str(PT_R22)"($29)\n\t"				\
-	"sd\t$23,"__str(PT_R23)"($29)\n\t"				\
-	"sd\t$30,"__str(PT_R30)"($29)\n\t"				\
-	"j\t" #symbol "\n\t"						\
-	".end\t__" #symbol "\n\t"					\
-	".size\t__" #symbol",. - __" #symbol)
-
-#endif /* CONFIG_64BIT */
-
-#endif /* _ASM_SIM_H */
diff --git a/arch/mips/include/asm/syscall.h b/arch/mips/include/asm/syscall.h
index 25fa651c937d..02ca0d659428 100644
--- a/arch/mips/include/asm/syscall.h
+++ b/arch/mips/include/asm/syscall.h
@@ -157,4 +157,9 @@ static inline int syscall_get_arch(struct task_struct *task)
 	return arch;
 }
 
+static inline bool arch_syscall_is_vdso_sigreturn(struct pt_regs *regs)
+{
+	return false;
+}
+
 #endif	/* __ASM_MIPS_SYSCALL_H */
diff --git a/arch/mips/include/asm/thread_info.h b/arch/mips/include/asm/thread_info.h
index 0b17aaa9e012..5a5237413065 100644
--- a/arch/mips/include/asm/thread_info.h
+++ b/arch/mips/include/asm/thread_info.h
@@ -29,7 +29,8 @@ struct thread_info {
 	__u32			cpu;		/* current CPU */
 	int			preempt_count;	/* 0 => preemptable, <0 => BUG */
 	struct pt_regs		*regs;
-	long			syscall;	/* syscall number */
+	unsigned long		syscall;	/* syscall number */
+	unsigned long		syscall_work;	/* SYSCALL_WORK_ flags */
 };
 
 /*
@@ -69,6 +70,8 @@ static inline struct thread_info *current_thread_info(void)
 	return __current_thread_info;
 }
 
+register unsigned long current_stack_pointer __asm__("$29");
+
 #endif /* !__ASSEMBLY__ */
 
 /* thread information allocation */
@@ -149,22 +152,10 @@ static inline struct thread_info *current_thread_info(void)
 #define _TIF_MSA_CTX_LIVE	(1<<TIF_MSA_CTX_LIVE)
 #define _TIF_SYSCALL_TRACEPOINT	(1<<TIF_SYSCALL_TRACEPOINT)
 
-#define _TIF_WORK_SYSCALL_ENTRY	(_TIF_NOHZ | _TIF_SYSCALL_TRACE |	\
-				 _TIF_SYSCALL_AUDIT | \
-				 _TIF_SYSCALL_TRACEPOINT | _TIF_SECCOMP)
-
-/* work to do in syscall_trace_leave() */
-#define _TIF_WORK_SYSCALL_EXIT	(_TIF_NOHZ | _TIF_SYSCALL_TRACE |	\
-				 _TIF_SYSCALL_AUDIT | _TIF_SYSCALL_TRACEPOINT)
-
 /* work to do on interrupt/exception return */
 #define _TIF_WORK_MASK		\
 	(_TIF_SIGPENDING | _TIF_NEED_RESCHED | _TIF_NOTIFY_RESUME |	\
 	 _TIF_UPROBE | _TIF_NOTIFY_SIGNAL)
-/* work to do on any return to u-space */
-#define _TIF_ALLWORK_MASK	(_TIF_NOHZ | _TIF_WORK_MASK |		\
-				 _TIF_WORK_SYSCALL_EXIT |		\
-				 _TIF_SYSCALL_TRACEPOINT)
 
 /*
  * We stash processor id into a COP0 register to retrieve it fast
diff --git a/arch/mips/include/uapi/asm/ptrace.h b/arch/mips/include/uapi/asm/ptrace.h
index f3c025445e45..27e2c85398bc 100644
--- a/arch/mips/include/uapi/asm/ptrace.h
+++ b/arch/mips/include/uapi/asm/ptrace.h
@@ -102,8 +102,9 @@ struct pt_watch_regs {
 	};
 };
 
-#define PTRACE_GET_WATCH_REGS	0xd0
-#define PTRACE_SET_WATCH_REGS	0xd1
-
+#define PTRACE_SYSEMU			0x1f
+#define PTRACE_SYSEMU_SINGLESTEP	0x20
+#define PTRACE_GET_WATCH_REGS		0xd0
+#define PTRACE_SET_WATCH_REGS		0xd1
 
 #endif /* _UAPI_ASM_PTRACE_H */
diff --git a/arch/mips/kernel/Makefile b/arch/mips/kernel/Makefile
index 814b3da30501..44875660f6ae 100644
--- a/arch/mips/kernel/Makefile
+++ b/arch/mips/kernel/Makefile
@@ -5,10 +5,10 @@
 
 extra-y		:= head.o vmlinux.lds
 
-obj-y		+= branch.o cmpxchg.o elf.o entry.o genex.o idle.o irq.o \
-		   process.o prom.o ptrace.o reset.o setup.o signal.o \
-		   syscall.o time.o topology.o traps.o unaligned.o watch.o \
-		   vdso.o cacheinfo.o
+obj-y		+= branch.o cacheinfo.o cmpxchg.o elf.o entry.o genex.o \
+		   idle.o irq.o process.o prom.o ptrace.o reset.o scall.o \
+		   setup.o signal.o syscall.o time.o topology.o traps.o \
+		   unaligned.o watch.o vdso.o
 
 ifdef CONFIG_CPU_R3K_TLB
 obj-y		+= cpu-r3k-probe.o
@@ -76,11 +76,9 @@ obj-$(CONFIG_IRQ_TXX9)		+= irq_txx9.o
 obj-$(CONFIG_IRQ_GT641XX)	+= irq-gt641xx.o
 
 obj-$(CONFIG_KPROBES)		+= kprobes.o
-obj-$(CONFIG_32BIT)		+= scall32-o32.o
-obj-$(CONFIG_64BIT)		+= scall64-n64.o
 obj-$(CONFIG_MIPS32_COMPAT)	+= linux32.o ptrace32.o signal32.o
-obj-$(CONFIG_MIPS32_N32)	+= scall64-n32.o signal_n32.o
-obj-$(CONFIG_MIPS32_O32)	+= scall64-o32.o signal_o32.o
+obj-$(CONFIG_MIPS32_N32)	+= signal_n32.o
+obj-$(CONFIG_MIPS32_O32)	+= signal_o32.o
 
 obj-$(CONFIG_KGDB)		+= kgdb.o
 obj-$(CONFIG_PROC_FS)		+= proc.o
diff --git a/arch/mips/kernel/entry.S b/arch/mips/kernel/entry.S
index 4b896f5023ff..1a2aec9dab1b 100644
--- a/arch/mips/kernel/entry.S
+++ b/arch/mips/kernel/entry.S
@@ -72,49 +72,32 @@ FEXPORT(ret_from_kernel_thread)
 	jal	schedule_tail		# a0 = struct task_struct *prev
 	move	a0, s1
 	jal	s0
-	j	syscall_exit
+	move	a0, sp
+	jal	syscall_exit_to_user_mode
+
+	.set	noat
+	RESTORE_STATIC
+	RESTORE_SOME
+	RESTORE_SP_AND_RET
+	.set	at
 
 FEXPORT(ret_from_fork)
 	jal	schedule_tail		# a0 = struct task_struct *prev
-
-FEXPORT(syscall_exit)
-#ifdef CONFIG_DEBUG_RSEQ
 	move	a0, sp
-	jal	rseq_syscall
-#endif
-	local_irq_disable		# make sure need_resched and
-					# signals dont change between
-					# sampling and return
-	LONG_L	a2, TI_FLAGS($28)	# current->work
-	li	t0, _TIF_ALLWORK_MASK
-	and	t0, a2, t0
-	bnez	t0, syscall_exit_work
+	jal	syscall_exit_to_user_mode
 
-restore_all:				# restore full frame
 	.set	noat
-	RESTORE_TEMP
-	RESTORE_AT
 	RESTORE_STATIC
-restore_partial:		# restore partial frame
-#ifdef CONFIG_TRACE_IRQFLAGS
-	SAVE_STATIC
-	SAVE_AT
-	SAVE_TEMP
-	LONG_L	v0, PT_STATUS(sp)
-#if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
-	and	v0, ST0_IEP
-#else
-	and	v0, ST0_IE
-#endif
-	beqz	v0, 1f
-	jal	trace_hardirqs_on
-	b	2f
-1:	jal	trace_hardirqs_off
-2:
+	RESTORE_SOME
+	RESTORE_SP_AND_RET
+	.set	at
+
+restore_all:				# restore full frame
+	.set	noat
 	RESTORE_TEMP
 	RESTORE_AT
 	RESTORE_STATIC
-#endif
+restore_partial:			# restore partial frame
 	RESTORE_SOME
 	RESTORE_SP_AND_RET
 	.set	at
@@ -143,32 +126,6 @@ work_notifysig:				# deal with pending signals and
 	jal	do_notify_resume	# a2 already loaded
 	j	resume_userspace_check
 
-FEXPORT(syscall_exit_partial)
-#ifdef CONFIG_DEBUG_RSEQ
-	move	a0, sp
-	jal	rseq_syscall
-#endif
-	local_irq_disable		# make sure need_resched doesn't
-					# change between and return
-	LONG_L	a2, TI_FLAGS($28)	# current->work
-	li	t0, _TIF_ALLWORK_MASK
-	and	t0, a2
-	beqz	t0, restore_partial
-	SAVE_STATIC
-syscall_exit_work:
-	LONG_L	t0, PT_STATUS(sp)		# returning to kernel mode?
-	andi	t0, t0, KU_USER
-	beqz	t0, resume_kernel
-	li	t0, _TIF_WORK_SYSCALL_EXIT
-	and	t0, a2			# a2 is preloaded with TI_FLAGS
-	beqz	t0, work_pending	# trace bit set?
-	local_irq_enable		# could let syscall_trace_leave()
-					# call schedule() instead
-	TRACE_IRQS_ON
-	move	a0, sp
-	jal	syscall_trace_leave
-	b	resume_userspace
-
 #if defined(CONFIG_CPU_MIPSR2) || defined(CONFIG_CPU_MIPSR5) || \
     defined(CONFIG_CPU_MIPSR6) || defined(CONFIG_MIPS_MT)
 
diff --git a/arch/mips/kernel/linux32.c b/arch/mips/kernel/linux32.c
index 6b61be486303..2b4b1fc1ff1b 100644
--- a/arch/mips/kernel/linux32.c
+++ b/arch/mips/kernel/linux32.c
@@ -38,7 +38,6 @@
 #include <net/scm.h>
 
 #include <asm/compat-signal.h>
-#include <asm/sim.h>
 #include <linux/uaccess.h>
 #include <asm/mmu_context.h>
 #include <asm/mman.h>
diff --git a/arch/mips/kernel/ptrace.c b/arch/mips/kernel/ptrace.c
index db7c5be1d4a3..04c08e41cfd3 100644
--- a/arch/mips/kernel/ptrace.c
+++ b/arch/mips/kernel/ptrace.c
@@ -46,9 +46,6 @@
 #include <asm/bootinfo.h>
 #include <asm/reg.h>
 
-#define CREATE_TRACE_POINTS
-#include <trace/events/syscalls.h>
-
 /*
  * Called by kernel/ptrace.c when detaching..
  *
@@ -1305,78 +1302,3 @@ long arch_ptrace(struct task_struct *child, long request,
  out:
 	return ret;
 }
-
-/*
- * Notification of system call entry/exit
- * - triggered by current->work.syscall_trace
- */
-asmlinkage long syscall_trace_enter(struct pt_regs *regs, long syscall)
-{
-	user_exit();
-
-	current_thread_info()->syscall = syscall;
-
-	if (test_thread_flag(TIF_SYSCALL_TRACE)) {
-		if (tracehook_report_syscall_entry(regs))
-			return -1;
-		syscall = current_thread_info()->syscall;
-	}
-
-#ifdef CONFIG_SECCOMP
-	if (unlikely(test_thread_flag(TIF_SECCOMP))) {
-		int ret, i;
-		struct seccomp_data sd;
-		unsigned long args[6];
-
-		sd.nr = syscall;
-		sd.arch = syscall_get_arch(current);
-		syscall_get_arguments(current, regs, args);
-		for (i = 0; i < 6; i++)
-			sd.args[i] = args[i];
-		sd.instruction_pointer = KSTK_EIP(current);
-
-		ret = __secure_computing(&sd);
-		if (ret == -1)
-			return ret;
-		syscall = current_thread_info()->syscall;
-	}
-#endif
-
-	if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
-		trace_sys_enter(regs, regs->regs[2]);
-
-	audit_syscall_entry(syscall, regs->regs[4], regs->regs[5],
-			    regs->regs[6], regs->regs[7]);
-
-	/*
-	 * Negative syscall numbers are mistaken for rejected syscalls, but
-	 * won't have had the return value set appropriately, so we do so now.
-	 */
-	if (syscall < 0)
-		syscall_set_return_value(current, regs, -ENOSYS, 0);
-	return syscall;
-}
-
-/*
- * Notification of system call entry/exit
- * - triggered by current->work.syscall_trace
- */
-asmlinkage void syscall_trace_leave(struct pt_regs *regs)
-{
-        /*
-	 * We may come here right after calling schedule_user()
-	 * or do_notify_resume(), in which case we can be in RCU
-	 * user mode.
-	 */
-	user_exit();
-
-	audit_syscall_exit(regs);
-
-	if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
-		trace_sys_exit(regs, regs_return_value(regs));
-
-	if (test_thread_flag(TIF_SYSCALL_TRACE))
-		tracehook_report_syscall_exit(regs, 0);
-
-	user_enter();
-}
diff --git a/arch/mips/kernel/scall.S b/arch/mips/kernel/scall.S
new file mode 100644
index 000000000000..7b35969151de
--- /dev/null
+++ b/arch/mips/kernel/scall.S
@@ -0,0 +1,135 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 1995, 96, 97, 98, 99, 2000, 01, 02 by Ralf Baechle
+ * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
+ * Copyright (C) 2001 MIPS Technologies, Inc.
+ * Copyright (C) 2004 Thiemo Seufer
+ * Copyright (C) 2014 Imagination Technologies Ltd.
+ */
+#include <linux/errno.h>
+#include <asm/asm.h>
+#include <asm/asmmacro.h>
+#include <asm/irqflags.h>
+#include <asm/mipsregs.h>
+#include <asm/regdef.h>
+#include <asm/stackframe.h>
+#include <asm/asm-offsets.h>
+#include <asm/sysmips.h>
+#include <asm/thread_info.h>
+#include <asm/unistd.h>
+#include <asm/war.h>
+
+	.align	5
+NESTED(handle_sys, PT_SIZE, sp)
+	.set	noat
+	SAVE_SOME
+	SAVE_STATIC
+	CLI
+	.set	at
+
+	move	a0, sp
+	jal	do_syscall
+
+	.set	noat
+	RESTORE_TEMP
+	RESTORE_AT
+	RESTORE_STATIC
+	RESTORE_SOME
+	RESTORE_SP_AND_RET
+	.set	at
+	END(handle_sys)
+
+#ifdef CONFIG_32BIT
+LEAF(sys_syscall)
+	subu	t0, a0, __NR_O32_Linux		# check syscall number
+	sltiu	v0, t0, __NR_O32_Linux_syscalls
+	beqz	t0, einval			# do not recurse
+	sll	t1, t0, 2
+	beqz	v0, einval
+	lw	t2, sys_call_table(t1)		# syscall routine
+
+	move	a0, a1				# shift argument registers
+	move	a1, a2
+	move	a2, a3
+	lw	a3, 16(sp)
+	lw	t4, 20(sp)
+	lw	t5, 24(sp)
+	lw	t6, 28(sp)
+	sw	t4, 16(sp)
+	sw	t5, 20(sp)
+	sw	t6, 24(sp)
+	jr	t2
+	/* Unreached */
+
+einval: li	v0, -ENOSYS
+	jr	ra
+	END(sys_syscall)
+
+#ifdef CONFIG_MIPS_MT_FPAFF
+	/*
+	 * For FPU affinity scheduling on MIPS MT processors, we need to
+	 * intercept sys_sched_xxxaffinity() calls until we get a proper hook
+	 * in kernel/sched/core.c.  Considered only temporary we only support
+	 * these hooks for the 32-bit kernel - there is no MIPS64 MT processor
+	 * atm.
+	 */
+#define sys_sched_setaffinity	mipsmt_sys_sched_setaffinity
+#define sys_sched_getaffinity	mipsmt_sys_sched_getaffinity
+#endif /* CONFIG_MIPS_MT_FPAFF */
+
+#define __SYSCALL_WITH_COMPAT(nr, native, compat)	__SYSCALL(nr, native)
+#define __SYSCALL(nr, entry) 	PTR entry
+	.align	2
+	.type	sys_call_table, @object
+EXPORT(sys_call_table)
+#include <asm/syscall_table_o32.h>
+#endif /* CONFIG_32BIT */
+
+#ifdef CONFIG_64BIT
+#ifdef CONFIG_MIPS32_O32
+LEAF(sys32_syscall)
+	subu	t0, a0, __NR_O32_Linux		# check syscall number
+	sltiu	v0, t0, __NR_O32_Linux_syscalls
+	beqz	t0, einval			# do not recurse
+	dsll	t1, t0, 3
+	beqz	v0, einval
+	ld	t2, sys32_call_table(t1)	# syscall routine
+
+	move	a0, a1				# shift argument registers
+	move	a1, a2
+	move	a2, a3
+	move	a3, a4
+	move	a4, a5
+	move	a5, a6
+	move	a6, a7
+	jr	t2
+	/* Unreached */
+
+einval: li	v0, -ENOSYS
+	jr	ra
+	END(sys32_syscall)
+
+#define __SYSCALL_WITH_COMPAT(nr, native, compat)	__SYSCALL(nr, compat)
+#define __SYSCALL(nr, entry)	PTR entry
+	.align	3
+	.type	sys32_call_table,@object
+EXPORT(sys32_call_table)
+#include <asm/syscall_table_o32.h>
+#endif /* CONFIG_MIPS32_O32 */
+
+#ifdef CONFIG_MIPS32_N32
+#undef __SYSCALL
+#define __SYSCALL(nr, entry)	PTR entry
+	.align	3
+	.type	sysn32_call_table, @object
+EXPORT(sysn32_call_table)
+#include <asm/syscall_table_n32.h>
+#endif /* CONFIG_MIPS32_N32 */
+
+#undef __SYSCALL
+#define __SYSCALL(nr, entry)	PTR entry
+	.align	3
+	.type	sys_call_table, @object
+EXPORT(sys_call_table)
+#include <asm/syscall_table_n64.h>
+#endif /* CONFIG_64BIT */
diff --git a/arch/mips/kernel/scall32-o32.S b/arch/mips/kernel/scall32-o32.S
deleted file mode 100644
index b1b2e106f711..000000000000
--- a/arch/mips/kernel/scall32-o32.S
+++ /dev/null
@@ -1,223 +0,0 @@
-/*
- * This file is subject to the terms and conditions of the GNU General Public
- * License.  See the file "COPYING" in the main directory of this archive
- * for more details.
- *
- * Copyright (C) 1995-99, 2000- 02, 06 Ralf Baechle <ralf@linux-mips.org>
- * Copyright (C) 2001 MIPS Technologies, Inc.
- * Copyright (C) 2004 Thiemo Seufer
- * Copyright (C) 2014 Imagination Technologies Ltd.
- */
-#include <linux/errno.h>
-#include <asm/asm.h>
-#include <asm/asmmacro.h>
-#include <asm/irqflags.h>
-#include <asm/mipsregs.h>
-#include <asm/regdef.h>
-#include <asm/stackframe.h>
-#include <asm/isadep.h>
-#include <asm/sysmips.h>
-#include <asm/thread_info.h>
-#include <asm/unistd.h>
-#include <asm/war.h>
-#include <asm/asm-offsets.h>
-
-	.align	5
-NESTED(handle_sys, PT_SIZE, sp)
-	.set	noat
-	SAVE_SOME
-	TRACE_IRQS_ON_RELOAD
-	STI
-	.set	at
-
-	lw	t1, PT_EPC(sp)		# skip syscall on return
-
-	addiu	t1, 4			# skip to next instruction
-	sw	t1, PT_EPC(sp)
-
-	sw	a3, PT_R26(sp)		# save a3 for syscall restarting
-
-	/*
-	 * More than four arguments.  Try to deal with it by copying the
-	 * stack arguments from the user stack to the kernel stack.
-	 * This Sucks (TM).
-	 */
-	lw	t0, PT_R29(sp)		# get old user stack pointer
-
-	/*
-	 * We intentionally keep the kernel stack a little below the top of
-	 * userspace so we don't have to do a slower byte accurate check here.
-	 */
-	addu	t4, t0, 32
-	bltz	t4, bad_stack		# -> sp is bad
-
-	/*
-	 * Ok, copy the args from the luser stack to the kernel stack.
-	 */
-
-	.set    push
-	.set    noreorder
-	.set	nomacro
-
-load_a4: user_lw(t5, 16(t0))		# argument #5 from usp
-load_a5: user_lw(t6, 20(t0))		# argument #6 from usp
-load_a6: user_lw(t7, 24(t0))		# argument #7 from usp
-load_a7: user_lw(t8, 28(t0))		# argument #8 from usp
-loads_done:
-
-	sw	t5, 16(sp)		# argument #5 to ksp
-	sw	t6, 20(sp)		# argument #6 to ksp
-	sw	t7, 24(sp)		# argument #7 to ksp
-	sw	t8, 28(sp)		# argument #8 to ksp
-	.set	pop
-
-	.section __ex_table,"a"
-	PTR	load_a4, bad_stack_a4
-	PTR	load_a5, bad_stack_a5
-	PTR	load_a6, bad_stack_a6
-	PTR	load_a7, bad_stack_a7
-	.previous
-
-	lw	t0, TI_FLAGS($28)	# syscall tracing enabled?
-	li	t1, _TIF_WORK_SYSCALL_ENTRY
-	and	t0, t1
-	bnez	t0, syscall_trace_entry # -> yes
-syscall_common:
-	subu	v0, v0, __NR_O32_Linux	# check syscall number
-	sltiu	t0, v0, __NR_O32_Linux_syscalls
-	beqz	t0, illegal_syscall
-
-	sll	t0, v0, 2
-	la	t1, sys_call_table
-	addu	t1, t0
-	lw	t2, (t1)		# syscall routine
-
-	beqz	t2, illegal_syscall
-
-	jalr	t2			# Do The Real Thing (TM)
-
-	li	t0, -EMAXERRNO - 1	# error?
-	sltu	t0, t0, v0
-	sw	t0, PT_R7(sp)		# set error flag
-	beqz	t0, 1f
-
-	lw	t1, PT_R2(sp)		# syscall number
-	negu	v0			# error
-	sw	t1, PT_R0(sp)		# save it for syscall restarting
-1:	sw	v0, PT_R2(sp)		# result
-
-o32_syscall_exit:
-	j	syscall_exit_partial
-
-/* ------------------------------------------------------------------------ */
-
-syscall_trace_entry:
-	SAVE_STATIC
-	move	a0, sp
-
-	/*
-	 * syscall number is in v0 unless we called syscall(__NR_###)
-	 * where the real syscall number is in a0
-	 */
-	move	a1, v0
-	subu	t2, v0,  __NR_O32_Linux
-	bnez	t2, 1f /* __NR_syscall at offset 0 */
-	lw	a1, PT_R4(sp)
-
-1:	jal	syscall_trace_enter
-
-	bltz	v0, 1f			# seccomp failed? Skip syscall
-
-	RESTORE_STATIC
-	lw	v0, PT_R2(sp)		# Restore syscall (maybe modified)
-	lw	a0, PT_R4(sp)		# Restore argument registers
-	lw	a1, PT_R5(sp)
-	lw	a2, PT_R6(sp)
-	lw	a3, PT_R7(sp)
-	j	syscall_common
-
-1:	j	syscall_exit
-
-/* ------------------------------------------------------------------------ */
-
-	/*
-	 * Our open-coded access area sanity test for the stack pointer
-	 * failed. We probably should handle this case a bit more drastic.
-	 */
-bad_stack:
-	li	v0, EFAULT
-	sw	v0, PT_R2(sp)
-	li	t0, 1				# set error flag
-	sw	t0, PT_R7(sp)
-	j	o32_syscall_exit
-
-bad_stack_a4:
-	li	t5, 0
-	b	load_a5
-
-bad_stack_a5:
-	li	t6, 0
-	b	load_a6
-
-bad_stack_a6:
-	li	t7, 0
-	b	load_a7
-
-bad_stack_a7:
-	li	t8, 0
-	b	loads_done
-
-	/*
-	 * The system call does not exist in this kernel
-	 */
-illegal_syscall:
-	li	v0, ENOSYS			# error
-	sw	v0, PT_R2(sp)
-	li	t0, 1				# set error flag
-	sw	t0, PT_R7(sp)
-	j	o32_syscall_exit
-	END(handle_sys)
-
-	LEAF(sys_syscall)
-	subu	t0, a0, __NR_O32_Linux	# check syscall number
-	sltiu	v0, t0, __NR_O32_Linux_syscalls
-	beqz	t0, einval		# do not recurse
-	sll	t1, t0, 2
-	beqz	v0, einval
-	lw	t2, sys_call_table(t1)		# syscall routine
-
-	move	a0, a1				# shift argument registers
-	move	a1, a2
-	move	a2, a3
-	lw	a3, 16(sp)
-	lw	t4, 20(sp)
-	lw	t5, 24(sp)
-	lw	t6, 28(sp)
-	sw	t4, 16(sp)
-	sw	t5, 20(sp)
-	sw	t6, 24(sp)
-	jr	t2
-	/* Unreached */
-
-einval: li	v0, -ENOSYS
-	jr	ra
-	END(sys_syscall)
-
-#ifdef CONFIG_MIPS_MT_FPAFF
-	/*
-	 * For FPU affinity scheduling on MIPS MT processors, we need to
-	 * intercept sys_sched_xxxaffinity() calls until we get a proper hook
-	 * in kernel/sched/core.c.  Considered only temporary we only support
-	 * these hooks for the 32-bit kernel - there is no MIPS64 MT processor
-	 * atm.
-	 */
-#define sys_sched_setaffinity	mipsmt_sys_sched_setaffinity
-#define sys_sched_getaffinity	mipsmt_sys_sched_getaffinity
-#endif /* CONFIG_MIPS_MT_FPAFF */
-
-#define __SYSCALL_WITH_COMPAT(nr, native, compat)	__SYSCALL(nr, native)
-#define __SYSCALL(nr, entry) 	PTR entry
-	.align	2
-	.type	sys_call_table, @object
-EXPORT(sys_call_table)
-#include <asm/syscall_table_o32.h>
diff --git a/arch/mips/kernel/scall64-n32.S b/arch/mips/kernel/scall64-n32.S
deleted file mode 100644
index f650c55a17dc..000000000000
--- a/arch/mips/kernel/scall64-n32.S
+++ /dev/null
@@ -1,107 +0,0 @@
-/*
- * This file is subject to the terms and conditions of the GNU General Public
- * License.  See the file "COPYING" in the main directory of this archive
- * for more details.
- *
- * Copyright (C) 1995, 96, 97, 98, 99, 2000, 01 by Ralf Baechle
- * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
- * Copyright (C) 2001 MIPS Technologies, Inc.
- */
-#include <linux/errno.h>
-#include <asm/asm.h>
-#include <asm/asmmacro.h>
-#include <asm/irqflags.h>
-#include <asm/mipsregs.h>
-#include <asm/regdef.h>
-#include <asm/stackframe.h>
-#include <asm/thread_info.h>
-#include <asm/unistd.h>
-
-#ifndef CONFIG_MIPS32_O32
-/* No O32, so define handle_sys here */
-#define handle_sysn32 handle_sys
-#endif
-
-	.align	5
-NESTED(handle_sysn32, PT_SIZE, sp)
-#ifndef CONFIG_MIPS32_O32
-	.set	noat
-	SAVE_SOME
-	TRACE_IRQS_ON_RELOAD
-	STI
-	.set	at
-#endif
-
-	dsubu	t0, v0, __NR_N32_Linux	# check syscall number
-	sltiu	t0, t0, __NR_N32_Linux_syscalls
-
-#ifndef CONFIG_MIPS32_O32
-	ld	t1, PT_EPC(sp)		# skip syscall on return
-	daddiu	t1, 4			# skip to next instruction
-	sd	t1, PT_EPC(sp)
-#endif
-	beqz	t0, not_n32_scall
-
-	sd	a3, PT_R26(sp)		# save a3 for syscall restarting
-
-	li	t1, _TIF_WORK_SYSCALL_ENTRY
-	LONG_L	t0, TI_FLAGS($28)	# syscall tracing enabled?
-	and	t0, t1, t0
-	bnez	t0, n32_syscall_trace_entry
-
-syscall_common:
-	dsll	t0, v0, 3		# offset into table
-	ld	t2, (sysn32_call_table - (__NR_N32_Linux * 8))(t0)
-
-	jalr	t2			# Do The Real Thing (TM)
-
-	li	t0, -EMAXERRNO - 1	# error?
-	sltu	t0, t0, v0
-	sd	t0, PT_R7(sp)		# set error flag
-	beqz	t0, 1f
-
-	ld	t1, PT_R2(sp)		# syscall number
-	dnegu	v0			# error
-	sd	t1, PT_R0(sp)		# save it for syscall restarting
-1:	sd	v0, PT_R2(sp)		# result
-
-	j	syscall_exit_partial
-
-/* ------------------------------------------------------------------------ */
-
-n32_syscall_trace_entry:
-	SAVE_STATIC
-	move	a0, sp
-	move	a1, v0
-	jal	syscall_trace_enter
-
-	bltz	v0, 1f			# seccomp failed? Skip syscall
-
-	RESTORE_STATIC
-	ld	v0, PT_R2(sp)		# Restore syscall (maybe modified)
-	ld	a0, PT_R4(sp)		# Restore argument registers
-	ld	a1, PT_R5(sp)
-	ld	a2, PT_R6(sp)
-	ld	a3, PT_R7(sp)
-	ld	a4, PT_R8(sp)
-	ld	a5, PT_R9(sp)
-
-	dsubu	t2, v0, __NR_N32_Linux	# check (new) syscall number
-	sltiu   t0, t2, __NR_N32_Linux_syscalls
-	beqz	t0, not_n32_scall
-
-	j	syscall_common
-
-1:	j	syscall_exit
-
-not_n32_scall:
-	/* This is not an n32 compatibility syscall, pass it on to
-	   the n64 syscall handlers.  */
-	j	handle_sys64
-
-	END(handle_sysn32)
-
-#define __SYSCALL(nr, entry)	PTR entry
-	.type	sysn32_call_table, @object
-EXPORT(sysn32_call_table)
-#include <asm/syscall_table_n32.h>
diff --git a/arch/mips/kernel/scall64-n64.S b/arch/mips/kernel/scall64-n64.S
deleted file mode 100644
index 5d7bfc65e4d0..000000000000
--- a/arch/mips/kernel/scall64-n64.S
+++ /dev/null
@@ -1,116 +0,0 @@
-/*
- * This file is subject to the terms and conditions of the GNU General Public
- * License.  See the file "COPYING" in the main directory of this archive
- * for more details.
- *
- * Copyright (C) 1995, 96, 97, 98, 99, 2000, 01, 02 by Ralf Baechle
- * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
- * Copyright (C) 2001 MIPS Technologies, Inc.
- */
-#include <linux/errno.h>
-#include <asm/asm.h>
-#include <asm/asmmacro.h>
-#include <asm/irqflags.h>
-#include <asm/mipsregs.h>
-#include <asm/regdef.h>
-#include <asm/stackframe.h>
-#include <asm/asm-offsets.h>
-#include <asm/sysmips.h>
-#include <asm/thread_info.h>
-#include <asm/unistd.h>
-#include <asm/war.h>
-
-#ifndef CONFIG_MIPS32_COMPAT
-/* Neither O32 nor N32, so define handle_sys here */
-#define handle_sys64 handle_sys
-#endif
-
-	.align	5
-NESTED(handle_sys64, PT_SIZE, sp)
-#if !defined(CONFIG_MIPS32_O32) && !defined(CONFIG_MIPS32_N32)
-	/*
-	 * When 32-bit compatibility is configured scall_o32.S
-	 * already did this.
-	 */
-	.set	noat
-	SAVE_SOME
-	TRACE_IRQS_ON_RELOAD
-	STI
-	.set	at
-#endif
-
-#if !defined(CONFIG_MIPS32_O32) && !defined(CONFIG_MIPS32_N32)
-	ld	t1, PT_EPC(sp)		# skip syscall on return
-	daddiu	t1, 4			# skip to next instruction
-	sd	t1, PT_EPC(sp)
-#endif
-
-	sd	a3, PT_R26(sp)		# save a3 for syscall restarting
-
-	li	t1, _TIF_WORK_SYSCALL_ENTRY
-	LONG_L	t0, TI_FLAGS($28)	# syscall tracing enabled?
-	and	t0, t1, t0
-	bnez	t0, syscall_trace_entry
-
-syscall_common:
-	dsubu	t2, v0, __NR_64_Linux
-	sltiu   t0, t2, __NR_64_Linux_syscalls
-	beqz	t0, illegal_syscall
-
-	dsll	t0, t2, 3		# offset into table
-	dla	t2, sys_call_table
-	daddu	t0, t2, t0
-	ld	t2, (t0)		# syscall routine
-	beqz	t2, illegal_syscall
-
-	jalr	t2			# Do The Real Thing (TM)
-
-	li	t0, -EMAXERRNO - 1	# error?
-	sltu	t0, t0, v0
-	sd	t0, PT_R7(sp)		# set error flag
-	beqz	t0, 1f
-
-	ld	t1, PT_R2(sp)		# syscall number
-	dnegu	v0			# error
-	sd	t1, PT_R0(sp)		# save it for syscall restarting
-1:	sd	v0, PT_R2(sp)		# result
-
-n64_syscall_exit:
-	j	syscall_exit_partial
-
-/* ------------------------------------------------------------------------ */
-
-syscall_trace_entry:
-	SAVE_STATIC
-	move	a0, sp
-	move	a1, v0
-	jal	syscall_trace_enter
-
-	bltz	v0, 1f			# seccomp failed? Skip syscall
-
-	RESTORE_STATIC
-	ld	v0, PT_R2(sp)		# Restore syscall (maybe modified)
-	ld	a0, PT_R4(sp)		# Restore argument registers
-	ld	a1, PT_R5(sp)
-	ld	a2, PT_R6(sp)
-	ld	a3, PT_R7(sp)
-	ld	a4, PT_R8(sp)
-	ld	a5, PT_R9(sp)
-	j	syscall_common
-
-1:	j	syscall_exit
-
-illegal_syscall:
-	/* This also isn't a 64-bit syscall, throw an error.  */
-	li	v0, ENOSYS			# error
-	sd	v0, PT_R2(sp)
-	li	t0, 1				# set error flag
-	sd	t0, PT_R7(sp)
-	j	n64_syscall_exit
-	END(handle_sys64)
-
-#define __SYSCALL(nr, entry)	PTR entry
-	.align	3
-	.type	sys_call_table, @object
-EXPORT(sys_call_table)
-#include <asm/syscall_table_n64.h>
diff --git a/arch/mips/kernel/scall64-o32.S b/arch/mips/kernel/scall64-o32.S
deleted file mode 100644
index cedc8bd88804..000000000000
--- a/arch/mips/kernel/scall64-o32.S
+++ /dev/null
@@ -1,221 +0,0 @@
-/*
- * This file is subject to the terms and conditions of the GNU General Public
- * License.  See the file "COPYING" in the main directory of this archive
- * for more details.
- *
- * Copyright (C) 1995 - 2000, 2001 by Ralf Baechle
- * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
- * Copyright (C) 2001 MIPS Technologies, Inc.
- * Copyright (C) 2004 Thiemo Seufer
- *
- * Hairy, the userspace application uses a different argument passing
- * convention than the kernel, so we have to translate things from o32
- * to ABI64 calling convention.	 64-bit syscalls are also processed
- * here for now.
- */
-#include <linux/errno.h>
-#include <asm/asm.h>
-#include <asm/asmmacro.h>
-#include <asm/irqflags.h>
-#include <asm/mipsregs.h>
-#include <asm/regdef.h>
-#include <asm/stackframe.h>
-#include <asm/thread_info.h>
-#include <asm/unistd.h>
-#include <asm/sysmips.h>
-
-	.align	5
-NESTED(handle_sys, PT_SIZE, sp)
-	.set	noat
-	SAVE_SOME
-	TRACE_IRQS_ON_RELOAD
-	STI
-	.set	at
-	ld	t1, PT_EPC(sp)		# skip syscall on return
-
-	dsubu	t0, v0, __NR_O32_Linux	# check syscall number
-	sltiu	t0, t0, __NR_O32_Linux_syscalls
-	daddiu	t1, 4			# skip to next instruction
-	sd	t1, PT_EPC(sp)
-	beqz	t0, not_o32_scall
-#if 0
- SAVE_ALL
- move a1, v0
- ASM_PRINT("Scall %ld\n")
- RESTORE_ALL
-#endif
-
-	/* We don't want to stumble over broken sign extensions from
-	   userland. O32 does never use the upper half. */
-	sll	a0, a0, 0
-	sll	a1, a1, 0
-	sll	a2, a2, 0
-	sll	a3, a3, 0
-
-	sd	a3, PT_R26(sp)		# save a3 for syscall restarting
-
-	/*
-	 * More than four arguments.  Try to deal with it by copying the
-	 * stack arguments from the user stack to the kernel stack.
-	 * This Sucks (TM).
-	 *
-	 * We intentionally keep the kernel stack a little below the top of
-	 * userspace so we don't have to do a slower byte accurate check here.
-	 */
-	ld	t0, PT_R29(sp)		# get old user stack pointer
-	daddu	t1, t0, 32
-	bltz	t1, bad_stack
-
-load_a4: lw	a4, 16(t0)		# argument #5 from usp
-load_a5: lw	a5, 20(t0)		# argument #6 from usp
-load_a6: lw	a6, 24(t0)		# argument #7 from usp
-load_a7: lw	a7, 28(t0)		# argument #8 from usp
-loads_done:
-
-	.section __ex_table,"a"
-	PTR	load_a4, bad_stack_a4
-	PTR	load_a5, bad_stack_a5
-	PTR	load_a6, bad_stack_a6
-	PTR	load_a7, bad_stack_a7
-	.previous
-
-	li	t1, _TIF_WORK_SYSCALL_ENTRY
-	LONG_L	t0, TI_FLAGS($28)	# syscall tracing enabled?
-	and	t0, t1, t0
-	bnez	t0, trace_a_syscall
-
-syscall_common:
-	dsll	t0, v0, 3		# offset into table
-	ld	t2, (sys32_call_table - (__NR_O32_Linux * 8))(t0)
-
-	jalr	t2			# Do The Real Thing (TM)
-
-	li	t0, -EMAXERRNO - 1	# error?
-	sltu	t0, t0, v0
-	sd	t0, PT_R7(sp)		# set error flag
-	beqz	t0, 1f
-
-	ld	t1, PT_R2(sp)		# syscall number
-	dnegu	v0			# error
-	sd	t1, PT_R0(sp)		# save it for syscall restarting
-1:	sd	v0, PT_R2(sp)		# result
-
-o32_syscall_exit:
-	j	syscall_exit_partial
-
-/* ------------------------------------------------------------------------ */
-
-trace_a_syscall:
-	SAVE_STATIC
-	sd	a4, PT_R8(sp)		# Save argument registers
-	sd	a5, PT_R9(sp)
-	sd	a6, PT_R10(sp)
-	sd	a7, PT_R11(sp)		# For indirect syscalls
-
-	move	a0, sp
-	/*
-	 * absolute syscall number is in v0 unless we called syscall(__NR_###)
-	 * where the real syscall number is in a0
-	 * note: NR_syscall is the first O32 syscall but the macro is
-	 * only defined when compiling with -mabi=32 (CONFIG_32BIT)
-	 * therefore __NR_O32_Linux is used (4000)
-	 */
-	.set	push
-	.set	reorder
-	subu	t1, v0,  __NR_O32_Linux
-	move	a1, v0
-	bnez	t1, 1f /* __NR_syscall at offset 0 */
-	ld	a1, PT_R4(sp) /* Arg1 for __NR_syscall case */
-	.set	pop
-
-1:	jal	syscall_trace_enter
-
-	bltz	v0, 1f			# seccomp failed? Skip syscall
-
-	RESTORE_STATIC
-	ld	v0, PT_R2(sp)		# Restore syscall (maybe modified)
-	ld	a0, PT_R4(sp)		# Restore argument registers
-	ld	a1, PT_R5(sp)
-	ld	a2, PT_R6(sp)
-	ld	a3, PT_R7(sp)
-	ld	a4, PT_R8(sp)
-	ld	a5, PT_R9(sp)
-	ld	a6, PT_R10(sp)
-	ld	a7, PT_R11(sp)		# For indirect syscalls
-
-	dsubu	t0, v0, __NR_O32_Linux	# check (new) syscall number
-	sltiu	t0, t0, __NR_O32_Linux_syscalls
-	beqz	t0, not_o32_scall
-
-	j	syscall_common
-
-1:	j	syscall_exit
-
-/* ------------------------------------------------------------------------ */
-
-	/*
-	 * The stackpointer for a call with more than 4 arguments is bad.
-	 */
-bad_stack:
-	li	v0, EFAULT
-	sd	v0, PT_R2(sp)
-	li	t0, 1			# set error flag
-	sd	t0, PT_R7(sp)
-	j	o32_syscall_exit
-
-bad_stack_a4:
-	li	a4, 0
-	b	load_a5
-
-bad_stack_a5:
-	li	a5, 0
-	b	load_a6
-
-bad_stack_a6:
-	li	a6, 0
-	b	load_a7
-
-bad_stack_a7:
-	li	a7, 0
-	b	loads_done
-
-not_o32_scall:
-	/*
-	 * This is not an o32 compatibility syscall, pass it on
-	 * to the 64-bit syscall handlers.
-	 */
-#ifdef CONFIG_MIPS32_N32
-	j	handle_sysn32
-#else
-	j	handle_sys64
-#endif
-	END(handle_sys)
-
-LEAF(sys32_syscall)
-	subu	t0, a0, __NR_O32_Linux	# check syscall number
-	sltiu	v0, t0, __NR_O32_Linux_syscalls
-	beqz	t0, einval		# do not recurse
-	dsll	t1, t0, 3
-	beqz	v0, einval
-	ld	t2, sys32_call_table(t1)		# syscall routine
-
-	move	a0, a1			# shift argument registers
-	move	a1, a2
-	move	a2, a3
-	move	a3, a4
-	move	a4, a5
-	move	a5, a6
-	move	a6, a7
-	jr	t2
-	/* Unreached */
-
-einval: li	v0, -ENOSYS
-	jr	ra
-	END(sys32_syscall)
-
-#define __SYSCALL_WITH_COMPAT(nr, native, compat)	__SYSCALL(nr, compat)
-#define __SYSCALL(nr, entry)	PTR entry
-	.align	3
-	.type	sys32_call_table,@object
-EXPORT(sys32_call_table)
-#include <asm/syscall_table_o32.h>
diff --git a/arch/mips/kernel/signal.c b/arch/mips/kernel/signal.c
index f1e985109da0..1ec6a0cf1163 100644
--- a/arch/mips/kernel/signal.c
+++ b/arch/mips/kernel/signal.c
@@ -32,7 +32,6 @@
 #include <linux/bitops.h>
 #include <asm/cacheflush.h>
 #include <asm/fpu.h>
-#include <asm/sim.h>
 #include <asm/ucontext.h>
 #include <asm/cpu-features.h>
 #include <asm/war.h>
@@ -627,7 +626,7 @@ SYSCALL_DEFINE3(sigaction, int, sig, const struct sigaction __user *, act,
 #endif
 
 #ifdef CONFIG_TRAD_SIGNALS
-asmlinkage void sys_sigreturn(void)
+asmlinkage long sys_sigreturn(void)
 {
 	struct sigframe __user *frame;
 	struct pt_regs *regs;
@@ -649,22 +648,16 @@ asmlinkage void sys_sigreturn(void)
 	else if (sig)
 		force_sig(sig);
 
-	/*
-	 * Don't let your children do this ...
-	 */
-	__asm__ __volatile__(
-		"move\t$29, %0\n\t"
-		"j\tsyscall_exit"
-		: /* no outputs */
-		: "r" (regs));
-	/* Unreached */
+	regs->regs[27] = 1;	/* return directly */
+	return regs->regs[2];
 
 badframe:
 	force_sig(SIGSEGV);
+	return 0;
 }
 #endif /* CONFIG_TRAD_SIGNALS */
 
-asmlinkage void sys_rt_sigreturn(void)
+asmlinkage long sys_rt_sigreturn(void)
 {
 	struct rt_sigframe __user *frame;
 	struct pt_regs *regs;
@@ -689,18 +682,12 @@ asmlinkage void sys_rt_sigreturn(void)
 	if (restore_altstack(&frame->rs_uc.uc_stack))
 		goto badframe;
 
-	/*
-	 * Don't let your children do this ...
-	 */
-	__asm__ __volatile__(
-		"move\t$29, %0\n\t"
-		"j\tsyscall_exit"
-		: /* no outputs */
-		: "r" (regs));
-	/* Unreached */
+	regs->regs[27] = 1;	/* return directly */
+	return regs->regs[2];
 
 badframe:
 	force_sig(SIGSEGV);
+	return 0;
 }
 
 #ifdef CONFIG_TRAD_SIGNALS
@@ -852,11 +839,11 @@ static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
 	signal_setup_done(ret, ksig, 0);
 }
 
-static void do_signal(struct pt_regs *regs)
+void arch_do_signal_or_restart(struct pt_regs *regs, bool has_signal)
 {
 	struct ksignal ksig;
 
-	if (get_signal(&ksig)) {
+	if (has_signal && get_signal(&ksig)) {
 		/* Whee!  Actually deliver the signal.	*/
 		handle_signal(&ksig, regs);
 		return;
@@ -904,7 +891,7 @@ asmlinkage void do_notify_resume(struct pt_regs *regs, void *unused,
 
 	/* deal with pending signal delivery */
 	if (thread_info_flags & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL))
-		do_signal(regs);
+		arch_do_signal_or_restart(regs, thread_info_flags & _TIF_SIGPENDING);
 
 	if (thread_info_flags & _TIF_NOTIFY_RESUME) {
 		tracehook_notify_resume(regs);
diff --git a/arch/mips/kernel/signal_n32.c b/arch/mips/kernel/signal_n32.c
index 7bd00fad61af..b52b995a8a9b 100644
--- a/arch/mips/kernel/signal_n32.c
+++ b/arch/mips/kernel/signal_n32.c
@@ -19,7 +19,6 @@
 #include <asm/asm.h>
 #include <asm/cacheflush.h>
 #include <asm/compat-signal.h>
-#include <asm/sim.h>
 #include <linux/uaccess.h>
 #include <asm/ucontext.h>
 #include <asm/fpu.h>
@@ -51,7 +50,7 @@ struct rt_sigframe_n32 {
 	struct ucontextn32 rs_uc;
 };
 
-asmlinkage void sysn32_rt_sigreturn(void)
+asmlinkage long sysn32_rt_sigreturn(void)
 {
 	struct rt_sigframe_n32 __user *frame;
 	struct pt_regs *regs;
@@ -76,18 +75,12 @@ asmlinkage void sysn32_rt_sigreturn(void)
 	if (compat_restore_altstack(&frame->rs_uc.uc_stack))
 		goto badframe;
 
-	/*
-	 * Don't let your children do this ...
-	 */
-	__asm__ __volatile__(
-		"move\t$29, %0\n\t"
-		"j\tsyscall_exit"
-		: /* no outputs */
-		: "r" (regs));
-	/* Unreached */
+	regs->regs[27] = 1;	/* return directly */
+	return regs->regs[2];
 
 badframe:
 	force_sig(SIGSEGV);
+	return 0;
 }
 
 static int setup_rt_frame_n32(void *sig_return, struct ksignal *ksig,
diff --git a/arch/mips/kernel/signal_o32.c b/arch/mips/kernel/signal_o32.c
index 299a7a28ca33..9245806e06f1 100644
--- a/arch/mips/kernel/signal_o32.c
+++ b/arch/mips/kernel/signal_o32.c
@@ -17,7 +17,6 @@
 #include <asm/abi.h>
 #include <asm/compat-signal.h>
 #include <asm/dsp.h>
-#include <asm/sim.h>
 #include <asm/unistd.h>
 
 #include "signal-common.h"
@@ -151,7 +150,7 @@ static int setup_frame_32(void *sig_return, struct ksignal *ksig,
 	return 0;
 }
 
-asmlinkage void sys32_rt_sigreturn(void)
+asmlinkage long sys32_rt_sigreturn(void)
 {
 	struct rt_sigframe32 __user *frame;
 	struct pt_regs *regs;
@@ -176,18 +175,12 @@ asmlinkage void sys32_rt_sigreturn(void)
 	if (compat_restore_altstack(&frame->rs_uc.uc_stack))
 		goto badframe;
 
-	/*
-	 * Don't let your children do this ...
-	 */
-	__asm__ __volatile__(
-		"move\t$29, %0\n\t"
-		"j\tsyscall_exit"
-		: /* no outputs */
-		: "r" (regs));
-	/* Unreached */
+	regs->regs[27] = 1;	/* return directly */
+	return regs->regs[2];
 
 badframe:
 	force_sig(SIGSEGV);
+	return 0;
 }
 
 static int setup_rt_frame_32(void *sig_return, struct ksignal *ksig,
@@ -253,7 +246,7 @@ struct mips_abi mips_abi_32 = {
 };
 
 
-asmlinkage void sys32_sigreturn(void)
+asmlinkage long sys32_sigreturn(void)
 {
 	struct sigframe32 __user *frame;
 	struct pt_regs *regs;
@@ -275,16 +268,10 @@ asmlinkage void sys32_sigreturn(void)
 	else if (sig)
 		force_sig(sig);
 
-	/*
-	 * Don't let your children do this ...
-	 */
-	__asm__ __volatile__(
-		"move\t$29, %0\n\t"
-		"j\tsyscall_exit"
-		: /* no outputs */
-		: "r" (regs));
-	/* Unreached */
+	regs->regs[27] = 1;	/* return directly */
+	return regs->regs[2];
 
 badframe:
 	force_sig(SIGSEGV);
+	return 0;
 }
diff --git a/arch/mips/kernel/syscall.c b/arch/mips/kernel/syscall.c
index 2afa3eef486a..6dc78648b274 100644
--- a/arch/mips/kernel/syscall.c
+++ b/arch/mips/kernel/syscall.c
@@ -8,6 +8,7 @@
  * Copyright (C) 2001 MIPS Technologies, Inc.
  */
 #include <linux/capability.h>
+#include <linux/entry-common.h>
 #include <linux/errno.h>
 #include <linux/linkage.h>
 #include <linux/fs.h>
@@ -35,9 +36,9 @@
 #include <asm/cacheflush.h>
 #include <asm/asm-offsets.h>
 #include <asm/signal.h>
-#include <asm/sim.h>
 #include <asm/shmparam.h>
 #include <asm/sync.h>
+#include <asm/syscall.h>
 #include <asm/sysmips.h>
 #include <asm/switch_to.h>
 
@@ -79,10 +80,6 @@ SYSCALL_DEFINE6(mips_mmap2, unsigned long, addr, unsigned long, len,
 			       pgoff >> (PAGE_SHIFT - 12));
 }
 
-save_static_function(sys_fork);
-save_static_function(sys_clone);
-save_static_function(sys_clone3);
-
 SYSCALL_DEFINE1(set_thread_area, unsigned long, addr)
 {
 	struct thread_info *ti = task_thread_info(current);
@@ -182,28 +179,11 @@ static inline int mips_atomic_set(unsigned long addr, unsigned long new)
 		return err;
 
 	regs = current_pt_regs();
-	regs->regs[2] = old;
-	regs->regs[7] = 0;	/* No error */
-
-	/*
-	 * Don't let your children do this ...
-	 */
-	__asm__ __volatile__(
-	"	move	$29, %0						\n"
-	"	j	syscall_exit					\n"
-	: /* no outputs */
-	: "r" (regs));
-
-	/* unreached.  Honestly.  */
-	unreachable();
+	regs->regs[7] = 0;	/* no error */
+	regs->regs[27] = 1;	/* return directly */
+	return old;
 }
 
-/*
- * mips_atomic_set() normally returns directly via syscall_exit potentially
- * clobbering static registers, so be sure to preserve them.
- */
-save_static_function(sys_sysmips);
-
 SYSCALL_DEFINE3(sysmips, long, cmd, long, arg1, long, arg2)
 {
 	switch (cmd) {
@@ -249,3 +229,120 @@ asmlinkage void bad_stack(void)
 {
 	do_exit(SIGSEGV);
 }
+
+#if defined(CONFIG_32BIT) || defined(CONFIG_MIPS32_O32)
+static inline int get_args(struct pt_regs *regs)
+{
+	int *usp = (int *)regs->regs[29];
+
+#ifdef CONFIG_MIPS32_O32
+	/*
+	 * Hairy, the userspace application uses a different argument passing
+	 * convention than the kernel, so we have to translate things from o32
+	 * to ABI64 calling convention.
+	 *
+	 * We don't want to stumble over broken sign extensions from userland.
+	 * O32 does never use the upper half.
+	 */
+	regs->regs[4] = (int)regs->regs[4];
+	regs->regs[5] = (int)regs->regs[5];
+	regs->regs[6] = (int)regs->regs[6];
+	regs->regs[7] = (int)regs->regs[7];
+#endif
+
+	/*
+	 * More than four arguments.  Try to deal with it by copying the
+	 * stack arguments from the user stack to the kernel stack.
+	 * This Sucks (TM).
+	 *
+	 * We intentionally keep the kernel stack a little below the top of
+	 * userspace so we don't have to do a slower byte accurate check here.
+	 */
+	if (!access_ok(usp, 32))
+		return -1;
+
+	get_user(regs->regs[8], usp + 4);
+	get_user(regs->regs[9], usp + 5);
+	get_user(regs->regs[10], usp + 6);
+	get_user(regs->regs[11], usp + 7);
+
+	return 0;
+}
+#endif
+
+typedef long (*sys_call_fn)(unsigned long, unsigned long,
+	unsigned long, unsigned long, unsigned long, unsigned long);
+
+void noinstr do_syscall(struct pt_regs *regs)
+{
+	unsigned long nr;
+	unsigned long ret;
+	sys_call_fn syscall_fn = NULL;
+
+	nr = regs->regs[2];
+	current_thread_info()->syscall = nr;
+	nr = syscall_enter_from_user_mode(regs, nr);
+
+	regs->cp0_epc += 4;		/* skip syscall on return */
+					/* skip to next instruction */
+	regs->regs[26] = regs->regs[7];	/* save a3 for syscall restarting */
+	regs->regs[27] = 0;		/* do not return directly */
+
+#ifdef CONFIG_32BIT
+	if (nr >= __NR_O32_Linux && nr < __NR_O32_Linux + __NR_O32_Linux_syscalls) {
+		if (get_args(regs) < 0) {
+			ret = EFAULT;
+			goto error;
+		}
+		syscall_fn = (sys_call_fn)sys_call_table[nr - __NR_O32_Linux];
+	}
+#endif
+
+#ifdef CONFIG_MIPS32_O32
+	if (nr >= __NR_O32_Linux && nr < __NR_O32_Linux + __NR_O32_Linux_syscalls) {
+		if (get_args(regs) < 0) {
+			ret = EFAULT;
+			goto error;
+		}
+		syscall_fn = (sys_call_fn)sys32_call_table[nr - __NR_O32_Linux];
+	}
+#endif
+
+#ifdef CONFIG_MIPS32_N32
+	if (nr >= __NR_N32_Linux && nr < __NR_N32_Linux + __NR_N32_Linux_syscalls)
+		syscall_fn = (sys_call_fn)sysn32_call_table[nr - __NR_N32_Linux];
+#endif
+
+#ifdef CONFIG_64BIT
+	if (nr >= __NR_64_Linux && nr < __NR_64_Linux + __NR_64_Linux_syscalls)
+		syscall_fn = (sys_call_fn)sys_call_table[nr - __NR_64_Linux];
+#endif
+
+	if (!syscall_fn) {
+		ret = ENOSYS;
+		goto error;
+	}
+
+	ret = syscall_fn(regs->regs[4], regs->regs[5], regs->regs[6],
+			 regs->regs[7], regs->regs[8], regs->regs[9]);
+
+	if (regs->regs[27])		/* return directly? */
+		goto out;
+
+	regs->regs[7] = 0;		/* clear error flag */
+	if (ret >= -EMAXERRNO - 1) {	/* error? */
+		regs->regs[0] = nr;	/* save syscall number */
+					/* for syscall restarting */
+		ret = -ret;
+		goto error;
+	}
+
+	goto out;
+
+error:
+	regs->regs[7] = 1;		/* set error flag */
+
+out:
+	regs->regs[2] = ret;
+	syscall_exit_to_user_mode(regs);
+}
diff --git a/arch/mips/kernel/syscalls/syscall_n32.tbl b/arch/mips/kernel/syscalls/syscall_n32.tbl
index 70e32de2bcaa..d9ae765e51f1 100644
--- a/arch/mips/kernel/syscalls/syscall_n32.tbl
+++ b/arch/mips/kernel/syscalls/syscall_n32.tbl
@@ -62,8 +62,8 @@
 52	n32	socketpair			sys_socketpair
 53	n32	setsockopt			sys_setsockopt
 54	n32	getsockopt			sys_getsockopt
-55	n32	clone				__sys_clone
-56	n32	fork				__sys_fork
+55	n32	clone				sys_clone
+56	n32	fork				sys_fork
 57	n32	execve				compat_sys_execve
 58	n32	exit				sys_exit
 59	n32	wait4				compat_sys_wait4
@@ -207,7 +207,7 @@
 196	n32	sched_getaffinity		compat_sys_sched_getaffinity
 197	n32	cacheflush			sys_cacheflush
 198	n32	cachectl			sys_cachectl
-199	n32	sysmips				__sys_sysmips
+199	n32	sysmips				sys_sysmips
 200	n32	io_setup			compat_sys_io_setup
 201	n32	io_destroy			sys_io_destroy
 202	n32	io_getevents			sys_io_getevents_time32
@@ -373,7 +373,7 @@
 432	n32	fsmount				sys_fsmount
 433	n32	fspick				sys_fspick
 434	n32	pidfd_open			sys_pidfd_open
-435	n32	clone3				__sys_clone3
+435	n32	clone3				sys_clone3
 436	n32	close_range			sys_close_range
 437	n32	openat2				sys_openat2
 438	n32	pidfd_getfd			sys_pidfd_getfd
diff --git a/arch/mips/kernel/syscalls/syscall_n64.tbl b/arch/mips/kernel/syscalls/syscall_n64.tbl
index 1ca7bc337932..edec3e82d67a 100644
--- a/arch/mips/kernel/syscalls/syscall_n64.tbl
+++ b/arch/mips/kernel/syscalls/syscall_n64.tbl
@@ -62,8 +62,8 @@
 52	n64	socketpair			sys_socketpair
 53	n64	setsockopt			sys_setsockopt
 54	n64	getsockopt			sys_getsockopt
-55	n64	clone				__sys_clone
-56	n64	fork				__sys_fork
+55	n64	clone				sys_clone
+56	n64	fork				sys_fork
 57	n64	execve				sys_execve
 58	n64	exit				sys_exit
 59	n64	wait4				sys_wait4
@@ -207,7 +207,7 @@
 196	n64	sched_getaffinity		sys_sched_getaffinity
 197	n64	cacheflush			sys_cacheflush
 198	n64	cachectl			sys_cachectl
-199	n64	sysmips				__sys_sysmips
+199	n64	sysmips				sys_sysmips
 200	n64	io_setup			sys_io_setup
 201	n64	io_destroy			sys_io_destroy
 202	n64	io_getevents			sys_io_getevents
@@ -349,7 +349,7 @@
 432	n64	fsmount				sys_fsmount
 433	n64	fspick				sys_fspick
 434	n64	pidfd_open			sys_pidfd_open
-435	n64	clone3				__sys_clone3
+435	n64	clone3				sys_clone3
 436	n64	close_range			sys_close_range
 437	n64	openat2				sys_openat2
 438	n64	pidfd_getfd			sys_pidfd_getfd
diff --git a/arch/mips/kernel/syscalls/syscall_o32.tbl b/arch/mips/kernel/syscalls/syscall_o32.tbl
index a61c35edaa74..89a1f267da6a 100644
--- a/arch/mips/kernel/syscalls/syscall_o32.tbl
+++ b/arch/mips/kernel/syscalls/syscall_o32.tbl
@@ -9,7 +9,7 @@
 #
 0	o32	syscall				sys_syscall			sys32_syscall
 1	o32	exit				sys_exit
-2	o32	fork				__sys_fork
+2	o32	fork				sys_fork
 3	o32	read				sys_read
 4	o32	write				sys_write
 5	o32	open				sys_open			compat_sys_open
@@ -131,7 +131,7 @@
 117	o32	ipc				sys_ipc				compat_sys_ipc
 118	o32	fsync				sys_fsync
 119	o32	sigreturn			sys_sigreturn			sys32_sigreturn
-120	o32	clone				__sys_clone
+120	o32	clone				sys_clone
 121	o32	setdomainname			sys_setdomainname
 122	o32	uname				sys_newuname
 123	o32	modify_ldt			sys_ni_syscall
@@ -160,7 +160,7 @@
 146	o32	writev				sys_writev
 147	o32	cacheflush			sys_cacheflush
 148	o32	cachectl			sys_cachectl
-149	o32	sysmips				__sys_sysmips
+149	o32	sysmips				sys_sysmips
 150	o32	unused150			sys_ni_syscall
 151	o32	getsid				sys_getsid
 152	o32	fdatasync			sys_fdatasync
@@ -422,7 +422,7 @@
 432	o32	fsmount				sys_fsmount
 433	o32	fspick				sys_fspick
 434	o32	pidfd_open			sys_pidfd_open
-435	o32	clone3				__sys_clone3
+435	o32	clone3				sys_clone3
 436	o32	close_range			sys_close_range
 437	o32	openat2				sys_openat2
 438	o32	pidfd_getfd			sys_pidfd_getfd
-- 
2.27.0


^ permalink raw reply	[flat|nested] 15+ messages in thread

* [PATCH 2/2] mips: convert irq to generic entry
  2021-09-07  6:16 [PATCH 0/2] mips: convert to generic entry FreeFlyingSheep
  2021-09-07  6:16 ` [PATCH 1/2] mips: convert syscall " FreeFlyingSheep
@ 2021-09-07  6:16 ` FreeFlyingSheep
  2021-09-08  7:17   ` Huacai Chen
  1 sibling, 1 reply; 15+ messages in thread
From: FreeFlyingSheep @ 2021-09-07  6:16 UTC (permalink / raw)
  To: tsbogend, tglx, peterz, luto, arnd
  Cc: Feiyang Chen, linux-mips, linux-arch, chenhuacai, jiaxun.yang,
	chris.chenfeiyang, Yanteng Si

From: Feiyang Chen <chenfeiyang@loongson.cn>

Convert mips irq to use the generic entry infrastructure from
kernel/entry/*.

When entering the handler functions written in C, there are three
status: STI, CLI and KMODE. Now use CLI for all handler functions,
since interrupts must be disabled before calling irqentry_enter().

- For handler functions who originally used STI, enable interrupts
after calling irqentry_enter().

- For handler functions who originally used KMODE, enable interrupts
after calling irqentry_enter() only if they are enabled in the parent
context.

- If CONFIG_HARDWARE_WATCHPOINTS is defined, interrupts will be enabled
after the watch registers are read. Only enable interrupts manually in
do_watch() if it is not defined.

The IRQ stack is disabled temporarily because it is too complex to
collaborate with the generic code (this will be improved by later
patches).

Signed-off-by: Feiyang Chen <chenfeiyang@loongson.cn>
Signed-off-by: Yanteng Si <siyanteng@loongson.cn>
---
 arch/mips/include/asm/irqflags.h   |  42 ------
 arch/mips/include/asm/stackframe.h |   8 ++
 arch/mips/kernel/entry.S           |  82 ------------
 arch/mips/kernel/genex.S           | 148 ++++-----------------
 arch/mips/kernel/head.S            |   1 -
 arch/mips/kernel/r4k-bugs64.c      |  14 +-
 arch/mips/kernel/scall.S           |   7 +-
 arch/mips/kernel/signal.c          |  26 ----
 arch/mips/kernel/traps.c           | 202 ++++++++++++++++++++---------
 arch/mips/kernel/unaligned.c       |  19 +--
 arch/mips/mm/c-octeon.c            |  15 +++
 arch/mips/mm/cex-oct.S             |   8 +-
 arch/mips/mm/fault.c               |  12 +-
 arch/mips/mm/tlbex-fault.S         |   7 +-
 14 files changed, 230 insertions(+), 361 deletions(-)

diff --git a/arch/mips/include/asm/irqflags.h b/arch/mips/include/asm/irqflags.h
index f5b8300f4573..ee7519b0d23f 100644
--- a/arch/mips/include/asm/irqflags.h
+++ b/arch/mips/include/asm/irqflags.h
@@ -11,8 +11,6 @@
 #ifndef _ASM_IRQFLAGS_H
 #define _ASM_IRQFLAGS_H
 
-#ifndef __ASSEMBLY__
-
 #include <linux/compiler.h>
 #include <linux/stringify.h>
 #include <asm/compiler.h>
@@ -142,44 +140,4 @@ static inline int arch_irqs_disabled(void)
 	return arch_irqs_disabled_flags(arch_local_save_flags());
 }
 
-#endif /* #ifndef __ASSEMBLY__ */
-
-/*
- * Do the CPU's IRQ-state tracing from assembly code.
- */
-#ifdef CONFIG_TRACE_IRQFLAGS
-/* Reload some registers clobbered by trace_hardirqs_on */
-#ifdef CONFIG_64BIT
-# define TRACE_IRQS_RELOAD_REGS						\
-	LONG_L	$11, PT_R11(sp);					\
-	LONG_L	$10, PT_R10(sp);					\
-	LONG_L	$9, PT_R9(sp);						\
-	LONG_L	$8, PT_R8(sp);						\
-	LONG_L	$7, PT_R7(sp);						\
-	LONG_L	$6, PT_R6(sp);						\
-	LONG_L	$5, PT_R5(sp);						\
-	LONG_L	$4, PT_R4(sp);						\
-	LONG_L	$2, PT_R2(sp)
-#else
-# define TRACE_IRQS_RELOAD_REGS						\
-	LONG_L	$7, PT_R7(sp);						\
-	LONG_L	$6, PT_R6(sp);						\
-	LONG_L	$5, PT_R5(sp);						\
-	LONG_L	$4, PT_R4(sp);						\
-	LONG_L	$2, PT_R2(sp)
-#endif
-# define TRACE_IRQS_ON							\
-	CLI;	/* make sure trace_hardirqs_on() is called in kernel level */ \
-	jal	trace_hardirqs_on
-# define TRACE_IRQS_ON_RELOAD						\
-	TRACE_IRQS_ON;							\
-	TRACE_IRQS_RELOAD_REGS
-# define TRACE_IRQS_OFF							\
-	jal	trace_hardirqs_off
-#else
-# define TRACE_IRQS_ON
-# define TRACE_IRQS_ON_RELOAD
-# define TRACE_IRQS_OFF
-#endif
-
 #endif /* _ASM_IRQFLAGS_H */
diff --git a/arch/mips/include/asm/stackframe.h b/arch/mips/include/asm/stackframe.h
index aa430a6c68b2..8bc74d7950fb 100644
--- a/arch/mips/include/asm/stackframe.h
+++ b/arch/mips/include/asm/stackframe.h
@@ -444,6 +444,14 @@
 		RESTORE_SP \docfi
 		.endm
 
+		.macro	RESTORE_ALL_AND_RET docfi=0
+		RESTORE_TEMP \docfi
+		RESTORE_STATIC \docfi
+		RESTORE_AT \docfi
+		RESTORE_SOME \docfi
+		RESTORE_SP_AND_RET \docfi
+		.endm
+
 /*
  * Move to kernel mode and disable interrupts.
  * Set cp0 enable bit as sign that we're running on the kernel stack
diff --git a/arch/mips/kernel/entry.S b/arch/mips/kernel/entry.S
index 1a2aec9dab1b..c9148831d820 100644
--- a/arch/mips/kernel/entry.S
+++ b/arch/mips/kernel/entry.S
@@ -11,7 +11,6 @@
 #include <asm/asm.h>
 #include <asm/asmmacro.h>
 #include <asm/compiler.h>
-#include <asm/irqflags.h>
 #include <asm/regdef.h>
 #include <asm/mipsregs.h>
 #include <asm/stackframe.h>
@@ -19,55 +18,8 @@
 #include <asm/thread_info.h>
 #include <asm/war.h>
 
-#ifndef CONFIG_PREEMPTION
-#define resume_kernel	restore_all
-#else
-#define __ret_from_irq	ret_from_exception
-#endif
-
 	.text
 	.align	5
-#ifndef CONFIG_PREEMPTION
-FEXPORT(ret_from_exception)
-	local_irq_disable			# preempt stop
-	b	__ret_from_irq
-#endif
-FEXPORT(ret_from_irq)
-	LONG_S	s0, TI_REGS($28)
-FEXPORT(__ret_from_irq)
-/*
- * We can be coming here from a syscall done in the kernel space,
- * e.g. a failed kernel_execve().
- */
-resume_userspace_check:
-	LONG_L	t0, PT_STATUS(sp)		# returning to kernel mode?
-	andi	t0, t0, KU_USER
-	beqz	t0, resume_kernel
-
-resume_userspace:
-	local_irq_disable		# make sure we dont miss an
-					# interrupt setting need_resched
-					# between sampling and return
-	LONG_L	a2, TI_FLAGS($28)	# current->work
-	andi	t0, a2, _TIF_WORK_MASK	# (ignoring syscall_trace)
-	bnez	t0, work_pending
-	j	restore_all
-
-#ifdef CONFIG_PREEMPTION
-resume_kernel:
-	local_irq_disable
-	lw	t0, TI_PRE_COUNT($28)
-	bnez	t0, restore_all
-	LONG_L	t0, TI_FLAGS($28)
-	andi	t1, t0, _TIF_NEED_RESCHED
-	beqz	t1, restore_all
-	LONG_L	t0, PT_STATUS(sp)		# Interrupts off?
-	andi	t0, 1
-	beqz	t0, restore_all
-	PTR_LA	ra, restore_all
-	j	preempt_schedule_irq
-#endif
-
 FEXPORT(ret_from_kernel_thread)
 	jal	schedule_tail		# a0 = struct task_struct *prev
 	move	a0, s1
@@ -92,40 +44,6 @@ FEXPORT(ret_from_fork)
 	RESTORE_SP_AND_RET
 	.set	at
 
-restore_all:				# restore full frame
-	.set	noat
-	RESTORE_TEMP
-	RESTORE_AT
-	RESTORE_STATIC
-restore_partial:			# restore partial frame
-	RESTORE_SOME
-	RESTORE_SP_AND_RET
-	.set	at
-
-work_pending:
-	andi	t0, a2, _TIF_NEED_RESCHED # a2 is preloaded with TI_FLAGS
-	beqz	t0, work_notifysig
-work_resched:
-	TRACE_IRQS_OFF
-	jal	schedule
-
-	local_irq_disable		# make sure need_resched and
-					# signals dont change between
-					# sampling and return
-	LONG_L	a2, TI_FLAGS($28)
-	andi	t0, a2, _TIF_WORK_MASK	# is there any work to be done
-					# other than syscall tracing?
-	beqz	t0, restore_all
-	andi	t0, a2, _TIF_NEED_RESCHED
-	bnez	t0, work_resched
-
-work_notifysig:				# deal with pending signals and
-					# notify-resume requests
-	move	a0, sp
-	li	a1, 0
-	jal	do_notify_resume	# a2 already loaded
-	j	resume_userspace_check
-
 #if defined(CONFIG_CPU_MIPSR2) || defined(CONFIG_CPU_MIPSR5) || \
     defined(CONFIG_CPU_MIPSR6) || defined(CONFIG_MIPS_MT)
 
diff --git a/arch/mips/kernel/genex.S b/arch/mips/kernel/genex.S
index 743d75927b71..60e288d307ff 100644
--- a/arch/mips/kernel/genex.S
+++ b/arch/mips/kernel/genex.S
@@ -13,7 +13,6 @@
 #include <asm/asm.h>
 #include <asm/asmmacro.h>
 #include <asm/cacheops.h>
-#include <asm/irqflags.h>
 #include <asm/regdef.h>
 #include <asm/fpregdef.h>
 #include <asm/mipsregs.h>
@@ -182,53 +181,16 @@ NESTED(handle_int, PT_SIZE, sp)
 #endif
 	SAVE_ALL docfi=1
 	CLI
-	TRACE_IRQS_OFF
 
-	LONG_L	s0, TI_REGS($28)
-	LONG_S	sp, TI_REGS($28)
-
-	/*
-	 * SAVE_ALL ensures we are using a valid kernel stack for the thread.
-	 * Check if we are already using the IRQ stack.
-	 */
-	move	s1, sp # Preserve the sp
-
-	/* Get IRQ stack for this CPU */
-	ASM_CPUID_MFC0	k0, ASM_SMP_CPUID_REG
-#if defined(CONFIG_32BIT) || defined(KBUILD_64BIT_SYM32)
-	lui	k1, %hi(irq_stack)
-#else
-	lui	k1, %highest(irq_stack)
-	daddiu	k1, %higher(irq_stack)
-	dsll	k1, 16
-	daddiu	k1, %hi(irq_stack)
-	dsll	k1, 16
-#endif
-	LONG_SRL	k0, SMP_CPUID_PTRSHIFT
-	LONG_ADDU	k1, k0
-	LONG_L	t0, %lo(irq_stack)(k1)
-
-	# Check if already on IRQ stack
-	PTR_LI	t1, ~(_THREAD_SIZE-1)
-	and	t1, t1, sp
-	beq	t0, t1, 2f
-
-	/* Switch to IRQ stack */
-	li	t1, _IRQ_STACK_START
-	PTR_ADD sp, t0, t1
-
-	/* Save task's sp on IRQ stack so that unwinding can follow it */
-	LONG_S	s1, 0(sp)
-2:
-	jal	plat_irq_dispatch
-
-	/* Restore sp */
-	move	sp, s1
-
-	j	ret_from_irq
+	move	a0, sp
+	jal	do_int
 #ifdef CONFIG_CPU_MICROMIPS
 	nop
 #endif
+
+	.set	noat
+	RESTORE_ALL_AND_RET
+	.set	at
 	END(handle_int)
 
 	__INIT
@@ -290,54 +252,12 @@ NESTED(except_vec_vi_handler, 0, sp)
 	SAVE_TEMP
 	SAVE_STATIC
 	CLI
-#ifdef CONFIG_TRACE_IRQFLAGS
-	move	s0, v0
-	TRACE_IRQS_OFF
-	move	v0, s0
-#endif
-
-	LONG_L	s0, TI_REGS($28)
-	LONG_S	sp, TI_REGS($28)
 
-	/*
-	 * SAVE_ALL ensures we are using a valid kernel stack for the thread.
-	 * Check if we are already using the IRQ stack.
-	 */
-	move	s1, sp # Preserve the sp
-
-	/* Get IRQ stack for this CPU */
-	ASM_CPUID_MFC0	k0, ASM_SMP_CPUID_REG
-#if defined(CONFIG_32BIT) || defined(KBUILD_64BIT_SYM32)
-	lui	k1, %hi(irq_stack)
-#else
-	lui	k1, %highest(irq_stack)
-	daddiu	k1, %higher(irq_stack)
-	dsll	k1, 16
-	daddiu	k1, %hi(irq_stack)
-	dsll	k1, 16
-#endif
-	LONG_SRL	k0, SMP_CPUID_PTRSHIFT
-	LONG_ADDU	k1, k0
-	LONG_L	t0, %lo(irq_stack)(k1)
-
-	# Check if already on IRQ stack
-	PTR_LI	t1, ~(_THREAD_SIZE-1)
-	and	t1, t1, sp
-	beq	t0, t1, 2f
-
-	/* Switch to IRQ stack */
-	li	t1, _IRQ_STACK_START
-	PTR_ADD sp, t0, t1
-
-	/* Save task's sp on IRQ stack so that unwinding can follow it */
-	LONG_S	s1, 0(sp)
-2:
-	jalr	v0
-
-	/* Restore sp */
-	move	sp, s1
+	move	a0, sp
+	move	a1, v0
+	jal	do_vi
 
-	j	ret_from_irq
+	RESTORE_ALL_AND_RET
 	END(except_vec_vi_handler)
 
 /*
@@ -462,22 +382,12 @@ NESTED(nmi_handler, PT_SIZE, sp)
 	.set	pop
 	END(nmi_handler)
 
-	.macro	__build_clear_none
-	.endm
-
-	.macro	__build_clear_sti
-	TRACE_IRQS_ON
-	STI
-	.endm
-
 	.macro	__build_clear_cli
 	CLI
-	TRACE_IRQS_OFF
 	.endm
 
 	.macro	__build_clear_fpe
 	CLI
-	TRACE_IRQS_OFF
 	.set	push
 	/* gas fails to assemble cfc1 for some archs (octeon).*/ \
 	.set	mips1
@@ -488,14 +398,13 @@ NESTED(nmi_handler, PT_SIZE, sp)
 
 	.macro	__build_clear_msa_fpe
 	CLI
-	TRACE_IRQS_OFF
 	_cfcmsa	a1, MSA_CSR
 	.endm
 
 	.macro	__build_clear_ade
 	MFC0	t0, CP0_BADVADDR
 	PTR_S	t0, PT_BVADDR(sp)
-	KMODE
+	CLI
 	.endm
 
 	.macro __build_clear_gsexc
@@ -507,8 +416,7 @@ NESTED(nmi_handler, PT_SIZE, sp)
 	.set	mips32
 	mfc0	a1, CP0_DIAGNOSTIC1
 	.set	pop
-	TRACE_IRQS_ON
-	STI
+	CLI
 	.endm
 
 	.macro	__BUILD_silent exception
@@ -547,7 +455,7 @@ NESTED(nmi_handler, PT_SIZE, sp)
 	__BUILD_\verbose \exception
 	move	a0, sp
 	jal	do_\handler
-	j	ret_from_exception
+	RESTORE_ALL_AND_RET
 	END(handle_\exception)
 	.endm
 
@@ -559,32 +467,28 @@ NESTED(nmi_handler, PT_SIZE, sp)
 	BUILD_HANDLER ades ade ade silent		/* #5  */
 	BUILD_HANDLER ibe be cli silent			/* #6  */
 	BUILD_HANDLER dbe be cli silent			/* #7  */
-	BUILD_HANDLER bp bp sti silent			/* #9  */
-	BUILD_HANDLER ri ri sti silent			/* #10 */
-	BUILD_HANDLER cpu cpu sti silent		/* #11 */
-	BUILD_HANDLER ov ov sti silent			/* #12 */
-	BUILD_HANDLER tr tr sti silent			/* #13 */
+	BUILD_HANDLER bp bp cli silent			/* #9  */
+	BUILD_HANDLER ri ri cli silent			/* #10 */
+	BUILD_HANDLER cpu cpu cli silent		/* #11 */
+	BUILD_HANDLER ov ov cli silent			/* #12 */
+	BUILD_HANDLER tr tr cli silent			/* #13 */
 	BUILD_HANDLER msa_fpe msa_fpe msa_fpe silent	/* #14 */
 #ifdef CONFIG_MIPS_FP_SUPPORT
 	BUILD_HANDLER fpe fpe fpe silent		/* #15 */
 #endif
-	BUILD_HANDLER ftlb ftlb none silent		/* #16 */
+	BUILD_HANDLER ftlb ftlb cli silent		/* #16 */
 	BUILD_HANDLER gsexc gsexc gsexc silent		/* #16 */
-	BUILD_HANDLER msa msa sti silent		/* #21 */
-	BUILD_HANDLER mdmx mdmx sti silent		/* #22 */
+	BUILD_HANDLER msa msa cli silent		/* #21 */
+	BUILD_HANDLER mdmx mdmx cli silent		/* #22 */
 #ifdef	CONFIG_HARDWARE_WATCHPOINTS
-	/*
-	 * For watch, interrupts will be enabled after the watch
-	 * registers are read.
-	 */
 	BUILD_HANDLER watch watch cli silent		/* #23 */
 #else
-	BUILD_HANDLER watch watch sti verbose		/* #23 */
+	BUILD_HANDLER watch watch cli verbose		/* #23 */
 #endif
 	BUILD_HANDLER mcheck mcheck cli verbose		/* #24 */
-	BUILD_HANDLER mt mt sti silent			/* #25 */
-	BUILD_HANDLER dsp dsp sti silent		/* #26 */
-	BUILD_HANDLER reserved reserved sti verbose	/* others */
+	BUILD_HANDLER mt mt cli silent			/* #25 */
+	BUILD_HANDLER dsp dsp cli silent		/* #26 */
+	BUILD_HANDLER reserved reserved cli verbose	/* others */
 
 	.align	5
 	LEAF(handle_ri_rdhwr_tlbp)
@@ -678,5 +582,5 @@ isrdhwr:
 
 	__INIT
 
-	BUILD_HANDLER  daddi_ov daddi_ov none silent	/* #12 */
+	BUILD_HANDLER  daddi_ov daddi_ov cli silent	/* #12 */
 #endif
diff --git a/arch/mips/kernel/head.S b/arch/mips/kernel/head.S
index b825ed4476c7..5f028dbd5961 100644
--- a/arch/mips/kernel/head.S
+++ b/arch/mips/kernel/head.S
@@ -19,7 +19,6 @@
 #include <asm/addrspace.h>
 #include <asm/asm.h>
 #include <asm/asmmacro.h>
-#include <asm/irqflags.h>
 #include <asm/regdef.h>
 #include <asm/mipsregs.h>
 #include <asm/stackframe.h>
diff --git a/arch/mips/kernel/r4k-bugs64.c b/arch/mips/kernel/r4k-bugs64.c
index 35729c9e6cfa..0384b649877c 100644
--- a/arch/mips/kernel/r4k-bugs64.c
+++ b/arch/mips/kernel/r4k-bugs64.c
@@ -3,6 +3,7 @@
  * Copyright (C) 2003, 2004, 2007  Maciej W. Rozycki
  */
 #include <linux/context_tracking.h>
+#include <linux/entry-common.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
 #include <linux/ptrace.h>
@@ -168,14 +169,19 @@ static __always_inline __init void check_mult_sh(void)
 
 static volatile int daddi_ov;
 
-asmlinkage void __init do_daddi_ov(struct pt_regs *regs)
+asmlinkage void noinstr __init do_daddi_ov(struct pt_regs *regs)
 {
-	enum ctx_state prev_state;
+	irqentry_state_t state = irqentry_enter(regs);
+
+	/* Enable interrupt if enabled in parent context */
+	if (likely(!regs_irqs_disabled(regs)))
+		local_irq_enable();
 
-	prev_state = exception_enter();
 	daddi_ov = 1;
 	regs->cp0_epc += 4;
-	exception_exit(prev_state);
+
+	local_irq_disable();
+	irqentry_exit(regs, state);
 }
 
 static __init void check_daddi(void)
diff --git a/arch/mips/kernel/scall.S b/arch/mips/kernel/scall.S
index 7b35969151de..3bd955ce5462 100644
--- a/arch/mips/kernel/scall.S
+++ b/arch/mips/kernel/scall.S
@@ -9,7 +9,6 @@
 #include <linux/errno.h>
 #include <asm/asm.h>
 #include <asm/asmmacro.h>
-#include <asm/irqflags.h>
 #include <asm/mipsregs.h>
 #include <asm/regdef.h>
 #include <asm/stackframe.h>
@@ -31,11 +30,7 @@ NESTED(handle_sys, PT_SIZE, sp)
 	jal	do_syscall
 
 	.set	noat
-	RESTORE_TEMP
-	RESTORE_AT
-	RESTORE_STATIC
-	RESTORE_SOME
-	RESTORE_SP_AND_RET
+	RESTORE_ALL_AND_RET
 	.set	at
 	END(handle_sys)
 
diff --git a/arch/mips/kernel/signal.c b/arch/mips/kernel/signal.c
index 1ec6a0cf1163..dbcfbaf03558 100644
--- a/arch/mips/kernel/signal.c
+++ b/arch/mips/kernel/signal.c
@@ -875,32 +875,6 @@ void arch_do_signal_or_restart(struct pt_regs *regs, bool has_signal)
 	restore_saved_sigmask();
 }
 
-/*
- * notification of userspace execution resumption
- * - triggered by the TIF_WORK_MASK flags
- */
-asmlinkage void do_notify_resume(struct pt_regs *regs, void *unused,
-	__u32 thread_info_flags)
-{
-	local_irq_enable();
-
-	user_exit();
-
-	if (thread_info_flags & _TIF_UPROBE)
-		uprobe_notify_resume(regs);
-
-	/* deal with pending signal delivery */
-	if (thread_info_flags & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL))
-		arch_do_signal_or_restart(regs, thread_info_flags & _TIF_SIGPENDING);
-
-	if (thread_info_flags & _TIF_NOTIFY_RESUME) {
-		tracehook_notify_resume(regs);
-		rseq_handle_notify_resume(NULL, regs);
-	}
-
-	user_enter();
-}
-
 #if defined(CONFIG_SMP) && defined(CONFIG_MIPS_FP_SUPPORT)
 static int smp_save_fp_context(void __user *sc)
 {
diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index 6f07362de5ce..69290e67dd68 100644
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -17,6 +17,7 @@
 #include <linux/compiler.h>
 #include <linux/context_tracking.h>
 #include <linux/cpu_pm.h>
+#include <linux/entry-common.h>
 #include <linux/kexec.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
@@ -438,15 +439,14 @@ static const struct exception_table_entry *search_dbe_tables(unsigned long addr)
 	return e;
 }
 
-asmlinkage void do_be(struct pt_regs *regs)
+asmlinkage void noinstr do_be(struct pt_regs *regs)
 {
+	irqentry_state_t state = irqentry_enter(regs);
 	const int field = 2 * sizeof(unsigned long);
 	const struct exception_table_entry *fixup = NULL;
 	int data = regs->cp0_cause & 4;
 	int action = MIPS_BE_FATAL;
-	enum ctx_state prev_state;
 
-	prev_state = exception_enter();
 	/* XXX For now.	 Fixme, this searches the wrong table ...  */
 	if (data && !user_mode(regs))
 		fixup = search_dbe_tables(exception_epc(regs));
@@ -486,7 +486,7 @@ asmlinkage void do_be(struct pt_regs *regs)
 	force_sig(SIGBUS);
 
 out:
-	exception_exit(prev_state);
+	irqentry_exit(regs, state);
 }
 
 /*
@@ -743,15 +743,18 @@ static int simulate_loongson3_cpucfg(struct pt_regs *regs,
 }
 #endif /* CONFIG_CPU_LOONGSON3_CPUCFG_EMULATION */
 
-asmlinkage void do_ov(struct pt_regs *regs)
+asmlinkage void noinstr do_ov(struct pt_regs *regs)
 {
-	enum ctx_state prev_state;
+	irqentry_state_t state = irqentry_enter(regs);
+
+	local_irq_enable();
 
-	prev_state = exception_enter();
 	die_if_kernel("Integer overflow", regs);
 
 	force_sig_fault(SIGFPE, FPE_INTOVF, (void __user *)regs->cp0_epc);
-	exception_exit(prev_state);
+
+	local_irq_disable();
+	irqentry_exit(regs, state);
 }
 
 #ifdef CONFIG_MIPS_FP_SUPPORT
@@ -865,13 +868,12 @@ static int simulate_fp(struct pt_regs *regs, unsigned int opcode,
 /*
  * XXX Delayed fp exceptions when doing a lazy ctx switch XXX
  */
-asmlinkage void do_fpe(struct pt_regs *regs, unsigned long fcr31)
+asmlinkage void noinstr do_fpe(struct pt_regs *regs, unsigned long fcr31)
 {
-	enum ctx_state prev_state;
+	irqentry_state_t state = irqentry_enter(regs);
 	void __user *fault_addr;
 	int sig;
 
-	prev_state = exception_enter();
 	if (notify_die(DIE_FP, "FP exception", regs, 0, current->thread.trap_nr,
 		       SIGFPE) == NOTIFY_STOP)
 		goto out;
@@ -916,7 +918,8 @@ asmlinkage void do_fpe(struct pt_regs *regs, unsigned long fcr31)
 	process_fpemu_return(sig, fault_addr, fcr31);
 
 out:
-	exception_exit(prev_state);
+	local_irq_disable();
+	irqentry_exit(regs, state);
 }
 
 /*
@@ -1018,14 +1021,16 @@ void do_trap_or_bp(struct pt_regs *regs, unsigned int code, int si_code,
 	}
 }
 
-asmlinkage void do_bp(struct pt_regs *regs)
+asmlinkage void noinstr do_bp(struct pt_regs *regs)
 {
-	unsigned long epc = msk_isa16_mode(exception_epc(regs));
-	unsigned int opcode, bcode;
-	enum ctx_state prev_state;
+	irqentry_state_t state = irqentry_enter(regs);
 	bool user = user_mode(regs);
+	unsigned int opcode, bcode;
+	unsigned long epc;
+
+	local_irq_enable();
 
-	prev_state = exception_enter();
+	epc = msk_isa16_mode(exception_epc(regs));
 	current->thread.trap_nr = (regs->cp0_cause >> 2) & 0x1f;
 	if (get_isa16_mode(regs->cp0_epc)) {
 		u16 instr[2];
@@ -1097,7 +1102,8 @@ asmlinkage void do_bp(struct pt_regs *regs)
 	do_trap_or_bp(regs, bcode, TRAP_BRKPT, "Break");
 
 out:
-	exception_exit(prev_state);
+	local_irq_disable();
+	irqentry_exit(regs, state);
 	return;
 
 out_sigsegv:
@@ -1105,15 +1111,17 @@ asmlinkage void do_bp(struct pt_regs *regs)
 	goto out;
 }
 
-asmlinkage void do_tr(struct pt_regs *regs)
+asmlinkage void noinstr do_tr(struct pt_regs *regs)
 {
+	irqentry_state_t state = irqentry_enter(regs);
+	bool user = user_mode(regs);
 	u32 opcode, tcode = 0;
-	enum ctx_state prev_state;
+	unsigned long epc;
 	u16 instr[2];
-	bool user = user_mode(regs);
-	unsigned long epc = msk_isa16_mode(exception_epc(regs));
 
-	prev_state = exception_enter();
+	local_irq_enable();
+
+	epc = msk_isa16_mode(exception_epc(regs));
 	current->thread.trap_nr = (regs->cp0_cause >> 2) & 0x1f;
 	if (get_isa16_mode(regs->cp0_epc)) {
 		if (__get_inst16(&instr[0], (u16 *)(epc + 0), user) ||
@@ -1134,7 +1142,8 @@ asmlinkage void do_tr(struct pt_regs *regs)
 	do_trap_or_bp(regs, tcode, 0, "Trap");
 
 out:
-	exception_exit(prev_state);
+	local_irq_disable();
+	irqentry_exit(regs, state);
 	return;
 
 out_sigsegv:
@@ -1142,15 +1151,19 @@ asmlinkage void do_tr(struct pt_regs *regs)
 	goto out;
 }
 
-asmlinkage void do_ri(struct pt_regs *regs)
+asmlinkage void noinstr do_ri(struct pt_regs *regs)
 {
-	unsigned int __user *epc = (unsigned int __user *)exception_epc(regs);
+	irqentry_state_t state = irqentry_enter(regs);
 	unsigned long old_epc = regs->cp0_epc;
 	unsigned long old31 = regs->regs[31];
-	enum ctx_state prev_state;
+	unsigned int __user *epc;
 	unsigned int opcode = 0;
 	int status = -1;
 
+	local_irq_enable();
+
+	epc = (unsigned int __user *)exception_epc(regs);
+
 	/*
 	 * Avoid any kernel code. Just emulate the R2 instruction
 	 * as quickly as possible.
@@ -1177,7 +1190,6 @@ asmlinkage void do_ri(struct pt_regs *regs)
 
 no_r2_instr:
 
-	prev_state = exception_enter();
 	current->thread.trap_nr = (regs->cp0_cause >> 2) & 0x1f;
 
 	if (notify_die(DIE_RI, "RI Fault", regs, 0, current->thread.trap_nr,
@@ -1233,7 +1245,8 @@ asmlinkage void do_ri(struct pt_regs *regs)
 	}
 
 out:
-	exception_exit(prev_state);
+	local_irq_disable();
+	irqentry_exit(regs, state);
 }
 
 /*
@@ -1393,16 +1406,17 @@ static int enable_restore_fp_context(int msa)
 
 #endif /* CONFIG_MIPS_FP_SUPPORT */
 
-asmlinkage void do_cpu(struct pt_regs *regs)
+asmlinkage void noinstr do_cpu(struct pt_regs *regs)
 {
-	enum ctx_state prev_state;
+	irqentry_state_t state = irqentry_enter(regs);
 	unsigned int __user *epc;
 	unsigned long old_epc, old31;
 	unsigned int opcode;
 	unsigned int cpid;
 	int status;
 
-	prev_state = exception_enter();
+	local_irq_enable();
+
 	cpid = (regs->cp0_cause >> CAUSEB_CE) & 3;
 
 	if (cpid != 2)
@@ -1495,14 +1509,14 @@ asmlinkage void do_cpu(struct pt_regs *regs)
 		break;
 	}
 
-	exception_exit(prev_state);
+	local_irq_disable();
+	irqentry_exit(regs, state);
 }
 
-asmlinkage void do_msa_fpe(struct pt_regs *regs, unsigned int msacsr)
+asmlinkage void noinstr do_msa_fpe(struct pt_regs *regs, unsigned int msacsr)
 {
-	enum ctx_state prev_state;
+	irqentry_state_t state = irqentry_enter(regs);
 
-	prev_state = exception_enter();
 	current->thread.trap_nr = (regs->cp0_cause >> 2) & 0x1f;
 	if (notify_die(DIE_MSAFP, "MSA FP exception", regs, 0,
 		       current->thread.trap_nr, SIGFPE) == NOTIFY_STOP)
@@ -1514,16 +1528,18 @@ asmlinkage void do_msa_fpe(struct pt_regs *regs, unsigned int msacsr)
 
 	die_if_kernel("do_msa_fpe invoked from kernel context!", regs);
 	force_sig(SIGFPE);
+
 out:
-	exception_exit(prev_state);
+	local_irq_disable();
+	irqentry_exit(regs, state);
 }
 
-asmlinkage void do_msa(struct pt_regs *regs)
+asmlinkage void noinstr do_msa(struct pt_regs *regs)
 {
-	enum ctx_state prev_state;
+	irqentry_state_t state = irqentry_enter(regs);
 	int err;
 
-	prev_state = exception_enter();
+	local_irq_enable();
 
 	if (!cpu_has_msa || test_thread_flag(TIF_32BIT_FPREGS)) {
 		force_sig(SIGILL);
@@ -1535,27 +1551,39 @@ asmlinkage void do_msa(struct pt_regs *regs)
 	err = enable_restore_fp_context(1);
 	if (err)
 		force_sig(SIGILL);
+
 out:
-	exception_exit(prev_state);
+	local_irq_disable();
+	irqentry_exit(regs, state);
 }
 
-asmlinkage void do_mdmx(struct pt_regs *regs)
+asmlinkage void noinstr do_mdmx(struct pt_regs *regs)
 {
-	enum ctx_state prev_state;
+	irqentry_state_t state = irqentry_enter(regs);
+
+	local_irq_enable();
 
-	prev_state = exception_enter();
 	force_sig(SIGILL);
-	exception_exit(prev_state);
+
+	local_irq_disable();
+	irqentry_exit(regs, state);
 }
 
 /*
  * Called with interrupts disabled.
  */
-asmlinkage void do_watch(struct pt_regs *regs)
+asmlinkage void noinstr do_watch(struct pt_regs *regs)
 {
-	enum ctx_state prev_state;
+	irqentry_state_t state = irqentry_enter(regs);
+
+#ifndef CONFIG_HARDWARE_WATCHPOINTS
+	/*
+	 * For watch, interrupts will be enabled after the watch
+	 * registers are read.
+	 */
+	local_irq_enable();
+#endif
 
-	prev_state = exception_enter();
 	/*
 	 * Clear WP (bit 22) bit of cause register so we don't loop
 	 * forever.
@@ -1575,15 +1603,16 @@ asmlinkage void do_watch(struct pt_regs *regs)
 		mips_clear_watch_registers();
 		local_irq_enable();
 	}
-	exception_exit(prev_state);
+
+	local_irq_disable();
+	irqentry_exit(regs, state);
 }
 
-asmlinkage void do_mcheck(struct pt_regs *regs)
+asmlinkage void noinstr do_mcheck(struct pt_regs *regs)
 {
+	irqentry_state_t state = irqentry_enter(regs);
 	int multi_match = regs->cp0_status & ST0_TS;
-	enum ctx_state prev_state;
 
-	prev_state = exception_enter();
 	show_regs(regs);
 
 	if (multi_match) {
@@ -1601,12 +1630,17 @@ asmlinkage void do_mcheck(struct pt_regs *regs)
 	panic("Caught Machine Check exception - %scaused by multiple "
 	      "matching entries in the TLB.",
 	      (multi_match) ? "" : "not ");
+
+	irqentry_exit(regs, state);
 }
 
-asmlinkage void do_mt(struct pt_regs *regs)
+asmlinkage void noinstr do_mt(struct pt_regs *regs)
 {
+	irqentry_state_t state = irqentry_enter(regs);
 	int subcode;
 
+	local_irq_enable();
+
 	subcode = (read_vpe_c0_vpecontrol() & VPECONTROL_EXCPT)
 			>> VPECONTROL_EXCPT_SHIFT;
 	switch (subcode) {
@@ -1636,19 +1670,33 @@ asmlinkage void do_mt(struct pt_regs *regs)
 	die_if_kernel("MIPS MT Thread exception in kernel", regs);
 
 	force_sig(SIGILL);
+
+	local_irq_disable();
+	irqentry_exit(regs, state);
 }
 
 
-asmlinkage void do_dsp(struct pt_regs *regs)
+asmlinkage void noinstr do_dsp(struct pt_regs *regs)
 {
+	irqentry_state_t state = irqentry_enter(regs);
+
+	local_irq_enable();
+
 	if (cpu_has_dsp)
 		panic("Unexpected DSP exception");
 
 	force_sig(SIGILL);
+
+	local_irq_disable();
+	irqentry_exit(regs, state);
 }
 
-asmlinkage void do_reserved(struct pt_regs *regs)
+asmlinkage void noinstr do_reserved(struct pt_regs *regs)
 {
+	irqentry_state_t state = irqentry_enter(regs);
+
+	local_irq_enable();
+
 	/*
 	 * Game over - no way to handle this if it ever occurs.	 Most probably
 	 * caused by a new unknown cpu type or after another deadly
@@ -1657,6 +1705,9 @@ asmlinkage void do_reserved(struct pt_regs *regs)
 	show_regs(regs);
 	panic("Caught reserved exception %ld - should not happen.",
 	      (regs->cp0_cause & 0x7f) >> 2);
+
+	local_irq_disable();
+	irqentry_exit(regs, state);
 }
 
 static int __initdata l1parity = 1;
@@ -1871,11 +1922,16 @@ asmlinkage void cache_parity_error(void)
 	panic("Can't handle the cache error!");
 }
 
-asmlinkage void do_ftlb(void)
+asmlinkage void noinstr do_ftlb(struct pt_regs *regs)
 {
+	irqentry_state_t state = irqentry_enter(regs);
 	const int field = 2 * sizeof(unsigned long);
 	unsigned int reg_val;
 
+	/* Enable interrupt if enabled in parent context */
+	if (likely(!regs_irqs_disabled(regs)))
+		local_irq_enable();
+
 	/* For the moment, report the problem and hang. */
 	if ((cpu_has_mips_r2_r6) &&
 	    (((current_cpu_data.processor_id & 0xff0000) == PRID_COMP_MIPS) ||
@@ -1898,16 +1954,17 @@ asmlinkage void do_ftlb(void)
 	}
 	/* Just print the cacheerr bits for now */
 	cache_parity_error();
+	local_irq_disable();
+	irqentry_exit(regs, state);
 }
 
-asmlinkage void do_gsexc(struct pt_regs *regs, u32 diag1)
+asmlinkage void noinstr do_gsexc(struct pt_regs *regs, u32 diag1)
 {
+	irqentry_state_t state = irqentry_enter(regs);
 	u32 exccode = (diag1 & LOONGSON_DIAG1_EXCCODE) >>
 			LOONGSON_DIAG1_EXCCODE_SHIFT;
-	enum ctx_state prev_state;
-
-	prev_state = exception_enter();
 
+	local_irq_enable();
 	switch (exccode) {
 	case 0x08:
 		/* Undocumented exception, will trigger on certain
@@ -1928,7 +1985,30 @@ asmlinkage void do_gsexc(struct pt_regs *regs, u32 diag1)
 		panic("Unhandled Loongson exception - GSCause = %08x", diag1);
 	}
 
-	exception_exit(prev_state);
+	local_irq_disable();
+	irqentry_exit(regs, state);
+}
+
+asmlinkage void noinstr do_int(struct pt_regs *regs)
+{
+	irqentry_state_t state = irqentry_enter(regs);
+	struct pt_regs *old_regs = set_irq_regs(regs);
+
+	plat_irq_dispatch();
+
+	set_irq_regs(old_regs);
+	irqentry_exit(regs, state);
+}
+
+asmlinkage void noinstr do_vi(struct pt_regs *regs, vi_handler_t handler)
+{
+	irqentry_state_t state = irqentry_enter(regs);
+	struct pt_regs *old_regs = set_irq_regs(regs);
+
+	handler();
+
+	set_irq_regs(old_regs);
+	irqentry_exit(regs, state);
 }
 
 /*
diff --git a/arch/mips/kernel/unaligned.c b/arch/mips/kernel/unaligned.c
index df4b708c04a9..fe46016a6afc 100644
--- a/arch/mips/kernel/unaligned.c
+++ b/arch/mips/kernel/unaligned.c
@@ -74,6 +74,7 @@
  *	 Undo the partial store in this case.
  */
 #include <linux/context_tracking.h>
+#include <linux/entry-common.h>
 #include <linux/mm.h>
 #include <linux/signal.h>
 #include <linux/smp.h>
@@ -1472,12 +1473,15 @@ static void emulate_load_store_MIPS16e(struct pt_regs *regs, void __user * addr)
 	force_sig(SIGILL);
 }
 
-asmlinkage void do_ade(struct pt_regs *regs)
+asmlinkage void noinstr do_ade(struct pt_regs *regs)
 {
-	enum ctx_state prev_state;
+	irqentry_state_t state = irqentry_enter(regs);
 	unsigned int *pc;
 
-	prev_state = exception_enter();
+	/* Enable interrupt if enabled in parent context */
+	if (likely(!regs_irqs_disabled(regs)))
+		local_irq_enable();
+
 	perf_sw_event(PERF_COUNT_SW_ALIGNMENT_FAULTS,
 			1, regs, regs->cp0_badvaddr);
 	/*
@@ -1530,16 +1534,15 @@ asmlinkage void do_ade(struct pt_regs *regs)
 
 	emulate_load_store_insn(regs, (void __user *)regs->cp0_badvaddr, pc);
 
-	return;
+	goto out;
 
 sigbus:
 	die_if_kernel("Kernel unaligned instruction access", regs);
 	force_sig(SIGBUS);
 
-	/*
-	 * XXX On return from the signal handler we should advance the epc
-	 */
-	exception_exit(prev_state);
+out:
+	local_irq_disable();
+	irqentry_exit(regs, state);
 }
 
 #ifdef CONFIG_DEBUG_FS
diff --git a/arch/mips/mm/c-octeon.c b/arch/mips/mm/c-octeon.c
index ec2ae501539a..e68c9e6c6480 100644
--- a/arch/mips/mm/c-octeon.c
+++ b/arch/mips/mm/c-octeon.c
@@ -5,6 +5,7 @@
  *
  * Copyright (C) 2005-2007 Cavium Networks
  */
+#include <linux/entry-common.h>
 #include <linux/export.h>
 #include <linux/kernel.h>
 #include <linux/sched.h>
@@ -349,3 +350,17 @@ asmlinkage void cache_parity_error_octeon_non_recoverable(void)
 	co_cache_error_call_notifiers(1);
 	panic("Can't handle cache error: nested exception");
 }
+
+asmlinkage void noinstr do_cache_err(struct pt_regs *regs)
+{
+	irqentry_state_t state = irqentry_enter(regs);
+
+	/* Enable interrupt if enabled in parent context */
+	if (likely(!regs_irqs_disabled(regs)))
+		local_irq_enable();
+
+	cache_parity_error_octeon_recoverable();
+
+	local_irq_disable();
+	irqentry_exit(regs, state);
+}
diff --git a/arch/mips/mm/cex-oct.S b/arch/mips/mm/cex-oct.S
index 9029092aa740..7d39087d208b 100644
--- a/arch/mips/mm/cex-oct.S
+++ b/arch/mips/mm/cex-oct.S
@@ -60,11 +60,11 @@
 	.set	noat
 
 	SAVE_ALL
-	KMODE
-	jal	cache_parity_error_octeon_recoverable
-	nop
-	j	ret_from_exception
+	CLI
+	move	a0, sp
+	jal	do_cache_err
 	nop
 
+	RESTORE_ALL_AND_RET
 	.set pop
 	END(handle_cache_err)
diff --git a/arch/mips/mm/fault.c b/arch/mips/mm/fault.c
index e7abda9c013f..e55bd45a596b 100644
--- a/arch/mips/mm/fault.c
+++ b/arch/mips/mm/fault.c
@@ -8,6 +8,7 @@
 #include <linux/context_tracking.h>
 #include <linux/signal.h>
 #include <linux/sched.h>
+#include <linux/entry-common.h>
 #include <linux/interrupt.h>
 #include <linux/kernel.h>
 #include <linux/errno.h>
@@ -327,9 +328,14 @@ static void __kprobes __do_page_fault(struct pt_regs *regs, unsigned long write,
 asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
 	unsigned long write, unsigned long address)
 {
-	enum ctx_state prev_state;
+	irqentry_state_t state = irqentry_enter(regs);
+
+	/* Enable interrupt if enabled in parent context */
+	if (likely(!regs_irqs_disabled(regs)))
+		local_irq_enable();
 
-	prev_state = exception_enter();
 	__do_page_fault(regs, write, address);
-	exception_exit(prev_state);
+
+	local_irq_disable();
+	irqentry_exit(regs, state);
 }
diff --git a/arch/mips/mm/tlbex-fault.S b/arch/mips/mm/tlbex-fault.S
index 77db401fc620..e16b4aa1fcc4 100644
--- a/arch/mips/mm/tlbex-fault.S
+++ b/arch/mips/mm/tlbex-fault.S
@@ -15,12 +15,15 @@
 	.cfi_signal_frame
 	SAVE_ALL docfi=1
 	MFC0	a2, CP0_BADVADDR
-	KMODE
+	CLI
 	move	a0, sp
 	REG_S	a2, PT_BVADDR(sp)
 	li	a1, \write
 	jal	do_page_fault
-	j	ret_from_exception
+
+	.set	noat
+	RESTORE_ALL_AND_RET
+	.set	at
 	END(tlb_do_page_fault_\write)
 	.endm
 
-- 
2.27.0


^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: [PATCH 1/2] mips: convert syscall to generic entry
  2021-09-07  6:16 ` [PATCH 1/2] mips: convert syscall " FreeFlyingSheep
@ 2021-09-07 13:48   ` Jiaxun Yang
  2021-09-08  2:08     ` 陈飞扬
  0 siblings, 1 reply; 15+ messages in thread
From: Jiaxun Yang @ 2021-09-07 13:48 UTC (permalink / raw)
  To: FreeFlyingSheep, tsbogend, tglx, peterz, luto, arnd
  Cc: Feiyang Chen, linux-mips, linux-arch, chenhuacai, Yanteng Si


在 2021/9/7 14:16, FreeFlyingSheep 写道:
> From: Feiyang Chen <chenfeiyang@loongson.cn>
>
> Convert mips syscall to use the generic entry infrastructure from
> kernel/entry/*.
>
> There are a few special things on mips:
>
> - There is one type of syscall on mips32 (scall32-o32) and three types
> of syscalls on mips64 (scall64-o32, scall64-n32 and scall64-n64). Now
> convert to C code to handle different types of syscalls.
>
> - For some special syscalls (e.g. fork, clone, clone3 and sysmips),
> save_static_function() wrapper is used to save static registers. Now
> SAVE_STATIC is used in handle_sys before calling do_syscall(), so the
> save_static_function() wrapper can be removed.
>
> - For sigreturn/rt_sigreturn and sysmips, inline assembly is used to
> jump to syscall_exit directly for skipping setting the error flag and
> restoring all registers. Now use regs->regs[27] to mark whether to
> handle the error flag and always restore all registers in handle_sys,
> so these functions can return normally as other architecture.

Hmm, that would give us overhead of register context on these syscalls.

I guess it's worthy?

>
> Signed-off-by: Feiyang Chen <chenfeiyang@loongson.cn>
> Signed-off-by: Yanteng Si <siyanteng@loongson.cn>

For the code,

Reviewed-by: Jiaxun Yang <jiaxun.yang@flygoat.com>

After spending 3hrs diving into syscall handling hell, I must say you've 
done a good job. I'll start a LTP run to see if we miss any corner 
cases. And left IRQ part for another trial.

Thanks.

Jiaxun

> ---
>   arch/mips/Kconfig                         |   1 +
>   arch/mips/include/asm/entry-common.h      |  13 ++
>   arch/mips/include/asm/ptrace.h            |   8 +-
>   arch/mips/include/asm/sim.h               |  70 -------
>   arch/mips/include/asm/syscall.h           |   5 +
>   arch/mips/include/asm/thread_info.h       |  17 +-
>   arch/mips/include/uapi/asm/ptrace.h       |   7 +-
>   arch/mips/kernel/Makefile                 |  14 +-
>   arch/mips/kernel/entry.S                  |  75 ++------
>   arch/mips/kernel/linux32.c                |   1 -
>   arch/mips/kernel/ptrace.c                 |  78 --------
>   arch/mips/kernel/scall.S                  | 135 +++++++++++++
>   arch/mips/kernel/scall32-o32.S            | 223 ----------------------
>   arch/mips/kernel/scall64-n32.S            | 107 -----------
>   arch/mips/kernel/scall64-n64.S            | 116 -----------
>   arch/mips/kernel/scall64-o32.S            | 221 ---------------------
>   arch/mips/kernel/signal.c                 |  35 ++--
>   arch/mips/kernel/signal_n32.c             |  15 +-
>   arch/mips/kernel/signal_o32.c             |  29 +--
>   arch/mips/kernel/syscall.c                | 147 +++++++++++---
>   arch/mips/kernel/syscalls/syscall_n32.tbl |   8 +-
>   arch/mips/kernel/syscalls/syscall_n64.tbl |   8 +-
>   arch/mips/kernel/syscalls/syscall_o32.tbl |   8 +-
>   23 files changed, 346 insertions(+), 995 deletions(-)
>   create mode 100644 arch/mips/include/asm/entry-common.h
>   delete mode 100644 arch/mips/include/asm/sim.h
>   create mode 100644 arch/mips/kernel/scall.S
>   delete mode 100644 arch/mips/kernel/scall32-o32.S
>   delete mode 100644 arch/mips/kernel/scall64-n32.S
>   delete mode 100644 arch/mips/kernel/scall64-n64.S
>   delete mode 100644 arch/mips/kernel/scall64-o32.S
>
> diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
> index 0cf31a6cbee1..61aa125aa2da 100644
> --- a/arch/mips/Kconfig
> +++ b/arch/mips/Kconfig
> @@ -32,6 +32,7 @@ config MIPS
>   	select GENERIC_ATOMIC64 if !64BIT
>   	select GENERIC_CMOS_UPDATE
>   	select GENERIC_CPU_AUTOPROBE
> +	select GENERIC_ENTRY
>   	select GENERIC_GETTIMEOFDAY
>   	select GENERIC_IOMAP
>   	select GENERIC_IRQ_PROBE
> diff --git a/arch/mips/include/asm/entry-common.h b/arch/mips/include/asm/entry-common.h
> new file mode 100644
> index 000000000000..0fe2a098ded9
> --- /dev/null
> +++ b/arch/mips/include/asm/entry-common.h
> @@ -0,0 +1,13 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef ARCH_LOONGARCH_ENTRY_COMMON_H
> +#define ARCH_LOONGARCH_ENTRY_COMMON_H
> +
> +#include <linux/sched.h>
> +#include <linux/processor.h>
> +
> +static inline bool on_thread_stack(void)
> +{
> +	return !(((unsigned long)(current->stack) ^ current_stack_pointer) & ~(THREAD_SIZE - 1));
> +}
> +
> +#endif
> diff --git a/arch/mips/include/asm/ptrace.h b/arch/mips/include/asm/ptrace.h
> index daf3cf244ea9..1b8f9d2ddc44 100644
> --- a/arch/mips/include/asm/ptrace.h
> +++ b/arch/mips/include/asm/ptrace.h
> @@ -51,6 +51,11 @@ struct pt_regs {
>   	unsigned long __last[0];
>   } __aligned(8);
>   
> +static inline int regs_irqs_disabled(struct pt_regs *regs)
> +{
> +	return arch_irqs_disabled_flags(regs->cp0_status);
> +}
> +
>   static inline unsigned long kernel_stack_pointer(struct pt_regs *regs)
>   {
>   	return regs->regs[29];
> @@ -156,9 +161,6 @@ static inline long regs_return_value(struct pt_regs *regs)
>   #define instruction_pointer(regs) ((regs)->cp0_epc)
>   #define profile_pc(regs) instruction_pointer(regs)
>   
> -extern asmlinkage long syscall_trace_enter(struct pt_regs *regs, long syscall);
> -extern asmlinkage void syscall_trace_leave(struct pt_regs *regs);
> -
>   extern void die(const char *, struct pt_regs *) __noreturn;
>   
>   static inline void die_if_kernel(const char *str, struct pt_regs *regs)
> diff --git a/arch/mips/include/asm/sim.h b/arch/mips/include/asm/sim.h
> deleted file mode 100644
> index 59f31a95facd..000000000000
> --- a/arch/mips/include/asm/sim.h
> +++ /dev/null
> @@ -1,70 +0,0 @@
> -/*
> - * This file is subject to the terms and conditions of the GNU General Public
> - * License.  See the file "COPYING" in the main directory of this archive
> - * for more details.
> - *
> - * Copyright (C) 1999, 2000, 2003 Ralf Baechle
> - * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
> - */
> -#ifndef _ASM_SIM_H
> -#define _ASM_SIM_H
> -
> -
> -#include <asm/asm-offsets.h>
> -
> -#define __str2(x) #x
> -#define __str(x) __str2(x)
> -
> -#ifdef CONFIG_32BIT
> -
> -#define save_static_function(symbol)					\
> -__asm__(								\
> -	".text\n\t"							\
> -	".globl\t__" #symbol "\n\t"					\
> -	".align\t2\n\t"							\
> -	".type\t__" #symbol ", @function\n\t"				\
> -	".ent\t__" #symbol ", 0\n__"					\
> -	#symbol":\n\t"							\
> -	".frame\t$29, 0, $31\n\t"					\
> -	"sw\t$16,"__str(PT_R16)"($29)\t\t\t# save_static_function\n\t"	\
> -	"sw\t$17,"__str(PT_R17)"($29)\n\t"				\
> -	"sw\t$18,"__str(PT_R18)"($29)\n\t"				\
> -	"sw\t$19,"__str(PT_R19)"($29)\n\t"				\
> -	"sw\t$20,"__str(PT_R20)"($29)\n\t"				\
> -	"sw\t$21,"__str(PT_R21)"($29)\n\t"				\
> -	"sw\t$22,"__str(PT_R22)"($29)\n\t"				\
> -	"sw\t$23,"__str(PT_R23)"($29)\n\t"				\
> -	"sw\t$30,"__str(PT_R30)"($29)\n\t"				\
> -	"j\t" #symbol "\n\t"						\
> -	".end\t__" #symbol "\n\t"					\
> -	".size\t__" #symbol",. - __" #symbol)
> -
> -#endif /* CONFIG_32BIT */
> -
> -#ifdef CONFIG_64BIT
> -
> -#define save_static_function(symbol)					\
> -__asm__(								\
> -	".text\n\t"							\
> -	".globl\t__" #symbol "\n\t"					\
> -	".align\t2\n\t"							\
> -	".type\t__" #symbol ", @function\n\t"				\
> -	".ent\t__" #symbol ", 0\n__"					\
> -	#symbol":\n\t"							\
> -	".frame\t$29, 0, $31\n\t"					\
> -	"sd\t$16,"__str(PT_R16)"($29)\t\t\t# save_static_function\n\t"	\
> -	"sd\t$17,"__str(PT_R17)"($29)\n\t"				\
> -	"sd\t$18,"__str(PT_R18)"($29)\n\t"				\
> -	"sd\t$19,"__str(PT_R19)"($29)\n\t"				\
> -	"sd\t$20,"__str(PT_R20)"($29)\n\t"				\
> -	"sd\t$21,"__str(PT_R21)"($29)\n\t"				\
> -	"sd\t$22,"__str(PT_R22)"($29)\n\t"				\
> -	"sd\t$23,"__str(PT_R23)"($29)\n\t"				\
> -	"sd\t$30,"__str(PT_R30)"($29)\n\t"				\
> -	"j\t" #symbol "\n\t"						\
> -	".end\t__" #symbol "\n\t"					\
> -	".size\t__" #symbol",. - __" #symbol)
> -
> -#endif /* CONFIG_64BIT */
> -
> -#endif /* _ASM_SIM_H */
> diff --git a/arch/mips/include/asm/syscall.h b/arch/mips/include/asm/syscall.h
> index 25fa651c937d..02ca0d659428 100644
> --- a/arch/mips/include/asm/syscall.h
> +++ b/arch/mips/include/asm/syscall.h
> @@ -157,4 +157,9 @@ static inline int syscall_get_arch(struct task_struct *task)
>   	return arch;
>   }
>   
> +static inline bool arch_syscall_is_vdso_sigreturn(struct pt_regs *regs)
> +{
> +	return false;
> +}
> +
>   #endif	/* __ASM_MIPS_SYSCALL_H */
> diff --git a/arch/mips/include/asm/thread_info.h b/arch/mips/include/asm/thread_info.h
> index 0b17aaa9e012..5a5237413065 100644
> --- a/arch/mips/include/asm/thread_info.h
> +++ b/arch/mips/include/asm/thread_info.h
> @@ -29,7 +29,8 @@ struct thread_info {
>   	__u32			cpu;		/* current CPU */
>   	int			preempt_count;	/* 0 => preemptable, <0 => BUG */
>   	struct pt_regs		*regs;
> -	long			syscall;	/* syscall number */
> +	unsigned long		syscall;	/* syscall number */
> +	unsigned long		syscall_work;	/* SYSCALL_WORK_ flags */
>   };
>   
>   /*
> @@ -69,6 +70,8 @@ static inline struct thread_info *current_thread_info(void)
>   	return __current_thread_info;
>   }
>   
> +register unsigned long current_stack_pointer __asm__("$29");
> +
>   #endif /* !__ASSEMBLY__ */
>   
>   /* thread information allocation */
> @@ -149,22 +152,10 @@ static inline struct thread_info *current_thread_info(void)
>   #define _TIF_MSA_CTX_LIVE	(1<<TIF_MSA_CTX_LIVE)
>   #define _TIF_SYSCALL_TRACEPOINT	(1<<TIF_SYSCALL_TRACEPOINT)
>   
> -#define _TIF_WORK_SYSCALL_ENTRY	(_TIF_NOHZ | _TIF_SYSCALL_TRACE |	\
> -				 _TIF_SYSCALL_AUDIT | \
> -				 _TIF_SYSCALL_TRACEPOINT | _TIF_SECCOMP)
> -
> -/* work to do in syscall_trace_leave() */
> -#define _TIF_WORK_SYSCALL_EXIT	(_TIF_NOHZ | _TIF_SYSCALL_TRACE |	\
> -				 _TIF_SYSCALL_AUDIT | _TIF_SYSCALL_TRACEPOINT)
> -
>   /* work to do on interrupt/exception return */
>   #define _TIF_WORK_MASK		\
>   	(_TIF_SIGPENDING | _TIF_NEED_RESCHED | _TIF_NOTIFY_RESUME |	\
>   	 _TIF_UPROBE | _TIF_NOTIFY_SIGNAL)
> -/* work to do on any return to u-space */
> -#define _TIF_ALLWORK_MASK	(_TIF_NOHZ | _TIF_WORK_MASK |		\
> -				 _TIF_WORK_SYSCALL_EXIT |		\
> -				 _TIF_SYSCALL_TRACEPOINT)
>   
>   /*
>    * We stash processor id into a COP0 register to retrieve it fast
> diff --git a/arch/mips/include/uapi/asm/ptrace.h b/arch/mips/include/uapi/asm/ptrace.h
> index f3c025445e45..27e2c85398bc 100644
> --- a/arch/mips/include/uapi/asm/ptrace.h
> +++ b/arch/mips/include/uapi/asm/ptrace.h
> @@ -102,8 +102,9 @@ struct pt_watch_regs {
>   	};
>   };
>   
> -#define PTRACE_GET_WATCH_REGS	0xd0
> -#define PTRACE_SET_WATCH_REGS	0xd1
> -
> +#define PTRACE_SYSEMU			0x1f
> +#define PTRACE_SYSEMU_SINGLESTEP	0x20
> +#define PTRACE_GET_WATCH_REGS		0xd0
> +#define PTRACE_SET_WATCH_REGS		0xd1
>   
>   #endif /* _UAPI_ASM_PTRACE_H */
> diff --git a/arch/mips/kernel/Makefile b/arch/mips/kernel/Makefile
> index 814b3da30501..44875660f6ae 100644
> --- a/arch/mips/kernel/Makefile
> +++ b/arch/mips/kernel/Makefile
> @@ -5,10 +5,10 @@
>   
>   extra-y		:= head.o vmlinux.lds
>   
> -obj-y		+= branch.o cmpxchg.o elf.o entry.o genex.o idle.o irq.o \
> -		   process.o prom.o ptrace.o reset.o setup.o signal.o \
> -		   syscall.o time.o topology.o traps.o unaligned.o watch.o \
> -		   vdso.o cacheinfo.o
> +obj-y		+= branch.o cacheinfo.o cmpxchg.o elf.o entry.o genex.o \
> +		   idle.o irq.o process.o prom.o ptrace.o reset.o scall.o \
> +		   setup.o signal.o syscall.o time.o topology.o traps.o \
> +		   unaligned.o watch.o vdso.o
>   
>   ifdef CONFIG_CPU_R3K_TLB
>   obj-y		+= cpu-r3k-probe.o
> @@ -76,11 +76,9 @@ obj-$(CONFIG_IRQ_TXX9)		+= irq_txx9.o
>   obj-$(CONFIG_IRQ_GT641XX)	+= irq-gt641xx.o
>   
>   obj-$(CONFIG_KPROBES)		+= kprobes.o
> -obj-$(CONFIG_32BIT)		+= scall32-o32.o
> -obj-$(CONFIG_64BIT)		+= scall64-n64.o
>   obj-$(CONFIG_MIPS32_COMPAT)	+= linux32.o ptrace32.o signal32.o
> -obj-$(CONFIG_MIPS32_N32)	+= scall64-n32.o signal_n32.o
> -obj-$(CONFIG_MIPS32_O32)	+= scall64-o32.o signal_o32.o
> +obj-$(CONFIG_MIPS32_N32)	+= signal_n32.o
> +obj-$(CONFIG_MIPS32_O32)	+= signal_o32.o
>   
>   obj-$(CONFIG_KGDB)		+= kgdb.o
>   obj-$(CONFIG_PROC_FS)		+= proc.o
> diff --git a/arch/mips/kernel/entry.S b/arch/mips/kernel/entry.S
> index 4b896f5023ff..1a2aec9dab1b 100644
> --- a/arch/mips/kernel/entry.S
> +++ b/arch/mips/kernel/entry.S
> @@ -72,49 +72,32 @@ FEXPORT(ret_from_kernel_thread)
>   	jal	schedule_tail		# a0 = struct task_struct *prev
>   	move	a0, s1
>   	jal	s0
> -	j	syscall_exit
> +	move	a0, sp
> +	jal	syscall_exit_to_user_mode
> +
> +	.set	noat
> +	RESTORE_STATIC
> +	RESTORE_SOME
> +	RESTORE_SP_AND_RET
> +	.set	at
>   
>   FEXPORT(ret_from_fork)
>   	jal	schedule_tail		# a0 = struct task_struct *prev
> -
> -FEXPORT(syscall_exit)
> -#ifdef CONFIG_DEBUG_RSEQ
>   	move	a0, sp
> -	jal	rseq_syscall
> -#endif
> -	local_irq_disable		# make sure need_resched and
> -					# signals dont change between
> -					# sampling and return
> -	LONG_L	a2, TI_FLAGS($28)	# current->work
> -	li	t0, _TIF_ALLWORK_MASK
> -	and	t0, a2, t0
> -	bnez	t0, syscall_exit_work
> +	jal	syscall_exit_to_user_mode
>   
> -restore_all:				# restore full frame
>   	.set	noat
> -	RESTORE_TEMP
> -	RESTORE_AT
>   	RESTORE_STATIC
> -restore_partial:		# restore partial frame
> -#ifdef CONFIG_TRACE_IRQFLAGS
> -	SAVE_STATIC
> -	SAVE_AT
> -	SAVE_TEMP
> -	LONG_L	v0, PT_STATUS(sp)
> -#if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
> -	and	v0, ST0_IEP
> -#else
> -	and	v0, ST0_IE
> -#endif
> -	beqz	v0, 1f
> -	jal	trace_hardirqs_on
> -	b	2f
> -1:	jal	trace_hardirqs_off
> -2:
> +	RESTORE_SOME
> +	RESTORE_SP_AND_RET
> +	.set	at
> +
> +restore_all:				# restore full frame
> +	.set	noat
>   	RESTORE_TEMP
>   	RESTORE_AT
>   	RESTORE_STATIC
> -#endif
> +restore_partial:			# restore partial frame
>   	RESTORE_SOME
>   	RESTORE_SP_AND_RET
>   	.set	at
> @@ -143,32 +126,6 @@ work_notifysig:				# deal with pending signals and
>   	jal	do_notify_resume	# a2 already loaded
>   	j	resume_userspace_check
>   
> -FEXPORT(syscall_exit_partial)
> -#ifdef CONFIG_DEBUG_RSEQ
> -	move	a0, sp
> -	jal	rseq_syscall
> -#endif
> -	local_irq_disable		# make sure need_resched doesn't
> -					# change between and return
> -	LONG_L	a2, TI_FLAGS($28)	# current->work
> -	li	t0, _TIF_ALLWORK_MASK
> -	and	t0, a2
> -	beqz	t0, restore_partial
> -	SAVE_STATIC
> -syscall_exit_work:
> -	LONG_L	t0, PT_STATUS(sp)		# returning to kernel mode?
> -	andi	t0, t0, KU_USER
> -	beqz	t0, resume_kernel
> -	li	t0, _TIF_WORK_SYSCALL_EXIT
> -	and	t0, a2			# a2 is preloaded with TI_FLAGS
> -	beqz	t0, work_pending	# trace bit set?
> -	local_irq_enable		# could let syscall_trace_leave()
> -					# call schedule() instead
> -	TRACE_IRQS_ON
> -	move	a0, sp
> -	jal	syscall_trace_leave
> -	b	resume_userspace
> -
>   #if defined(CONFIG_CPU_MIPSR2) || defined(CONFIG_CPU_MIPSR5) || \
>       defined(CONFIG_CPU_MIPSR6) || defined(CONFIG_MIPS_MT)
>   
> diff --git a/arch/mips/kernel/linux32.c b/arch/mips/kernel/linux32.c
> index 6b61be486303..2b4b1fc1ff1b 100644
> --- a/arch/mips/kernel/linux32.c
> +++ b/arch/mips/kernel/linux32.c
> @@ -38,7 +38,6 @@
>   #include <net/scm.h>
>   
>   #include <asm/compat-signal.h>
> -#include <asm/sim.h>
>   #include <linux/uaccess.h>
>   #include <asm/mmu_context.h>
>   #include <asm/mman.h>
> diff --git a/arch/mips/kernel/ptrace.c b/arch/mips/kernel/ptrace.c
> index db7c5be1d4a3..04c08e41cfd3 100644
> --- a/arch/mips/kernel/ptrace.c
> +++ b/arch/mips/kernel/ptrace.c
> @@ -46,9 +46,6 @@
>   #include <asm/bootinfo.h>
>   #include <asm/reg.h>
>   
> -#define CREATE_TRACE_POINTS
> -#include <trace/events/syscalls.h>
> -
>   /*
>    * Called by kernel/ptrace.c when detaching..
>    *
> @@ -1305,78 +1302,3 @@ long arch_ptrace(struct task_struct *child, long request,
>    out:
>   	return ret;
>   }
> -
> -/*
> - * Notification of system call entry/exit
> - * - triggered by current->work.syscall_trace
> - */
> -asmlinkage long syscall_trace_enter(struct pt_regs *regs, long syscall)
> -{
> -	user_exit();
> -
> -	current_thread_info()->syscall = syscall;
> -
> -	if (test_thread_flag(TIF_SYSCALL_TRACE)) {
> -		if (tracehook_report_syscall_entry(regs))
> -			return -1;
> -		syscall = current_thread_info()->syscall;
> -	}
> -
> -#ifdef CONFIG_SECCOMP
> -	if (unlikely(test_thread_flag(TIF_SECCOMP))) {
> -		int ret, i;
> -		struct seccomp_data sd;
> -		unsigned long args[6];
> -
> -		sd.nr = syscall;
> -		sd.arch = syscall_get_arch(current);
> -		syscall_get_arguments(current, regs, args);
> -		for (i = 0; i < 6; i++)
> -			sd.args[i] = args[i];
> -		sd.instruction_pointer = KSTK_EIP(current);
> -
> -		ret = __secure_computing(&sd);
> -		if (ret == -1)
> -			return ret;
> -		syscall = current_thread_info()->syscall;
> -	}
> -#endif
> -
> -	if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
> -		trace_sys_enter(regs, regs->regs[2]);
> -
> -	audit_syscall_entry(syscall, regs->regs[4], regs->regs[5],
> -			    regs->regs[6], regs->regs[7]);
> -
> -	/*
> -	 * Negative syscall numbers are mistaken for rejected syscalls, but
> -	 * won't have had the return value set appropriately, so we do so now.
> -	 */
> -	if (syscall < 0)
> -		syscall_set_return_value(current, regs, -ENOSYS, 0);
> -	return syscall;
> -}
> -
> -/*
> - * Notification of system call entry/exit
> - * - triggered by current->work.syscall_trace
> - */
> -asmlinkage void syscall_trace_leave(struct pt_regs *regs)
> -{
> -        /*
> -	 * We may come here right after calling schedule_user()
> -	 * or do_notify_resume(), in which case we can be in RCU
> -	 * user mode.
> -	 */
> -	user_exit();
> -
> -	audit_syscall_exit(regs);
> -
> -	if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
> -		trace_sys_exit(regs, regs_return_value(regs));
> -
> -	if (test_thread_flag(TIF_SYSCALL_TRACE))
> -		tracehook_report_syscall_exit(regs, 0);
> -
> -	user_enter();
> -}
> diff --git a/arch/mips/kernel/scall.S b/arch/mips/kernel/scall.S
> new file mode 100644
> index 000000000000..7b35969151de
> --- /dev/null
> +++ b/arch/mips/kernel/scall.S
> @@ -0,0 +1,135 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (C) 1995, 96, 97, 98, 99, 2000, 01, 02 by Ralf Baechle
> + * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
> + * Copyright (C) 2001 MIPS Technologies, Inc.
> + * Copyright (C) 2004 Thiemo Seufer
> + * Copyright (C) 2014 Imagination Technologies Ltd.
> + */
> +#include <linux/errno.h>
> +#include <asm/asm.h>
> +#include <asm/asmmacro.h>
> +#include <asm/irqflags.h>
> +#include <asm/mipsregs.h>
> +#include <asm/regdef.h>
> +#include <asm/stackframe.h>
> +#include <asm/asm-offsets.h>
> +#include <asm/sysmips.h>
> +#include <asm/thread_info.h>
> +#include <asm/unistd.h>
> +#include <asm/war.h>
> +
> +	.align	5
> +NESTED(handle_sys, PT_SIZE, sp)
> +	.set	noat
> +	SAVE_SOME
> +	SAVE_STATIC
> +	CLI
> +	.set	at
> +
> +	move	a0, sp
> +	jal	do_syscall
> +
> +	.set	noat
> +	RESTORE_TEMP
> +	RESTORE_AT
> +	RESTORE_STATIC
> +	RESTORE_SOME
> +	RESTORE_SP_AND_RET
> +	.set	at
> +	END(handle_sys)
> +
> +#ifdef CONFIG_32BIT
> +LEAF(sys_syscall)
> +	subu	t0, a0, __NR_O32_Linux		# check syscall number
> +	sltiu	v0, t0, __NR_O32_Linux_syscalls
> +	beqz	t0, einval			# do not recurse
> +	sll	t1, t0, 2
> +	beqz	v0, einval
> +	lw	t2, sys_call_table(t1)		# syscall routine
> +
> +	move	a0, a1				# shift argument registers
> +	move	a1, a2
> +	move	a2, a3
> +	lw	a3, 16(sp)
> +	lw	t4, 20(sp)
> +	lw	t5, 24(sp)
> +	lw	t6, 28(sp)
> +	sw	t4, 16(sp)
> +	sw	t5, 20(sp)
> +	sw	t6, 24(sp)
> +	jr	t2
> +	/* Unreached */
> +
> +einval: li	v0, -ENOSYS
> +	jr	ra
> +	END(sys_syscall)
> +
> +#ifdef CONFIG_MIPS_MT_FPAFF
> +	/*
> +	 * For FPU affinity scheduling on MIPS MT processors, we need to
> +	 * intercept sys_sched_xxxaffinity() calls until we get a proper hook
> +	 * in kernel/sched/core.c.  Considered only temporary we only support
> +	 * these hooks for the 32-bit kernel - there is no MIPS64 MT processor
> +	 * atm.
> +	 */
> +#define sys_sched_setaffinity	mipsmt_sys_sched_setaffinity
> +#define sys_sched_getaffinity	mipsmt_sys_sched_getaffinity
> +#endif /* CONFIG_MIPS_MT_FPAFF */
> +
> +#define __SYSCALL_WITH_COMPAT(nr, native, compat)	__SYSCALL(nr, native)
> +#define __SYSCALL(nr, entry) 	PTR entry
> +	.align	2
> +	.type	sys_call_table, @object
> +EXPORT(sys_call_table)
> +#include <asm/syscall_table_o32.h>
> +#endif /* CONFIG_32BIT */
> +
> +#ifdef CONFIG_64BIT
> +#ifdef CONFIG_MIPS32_O32
> +LEAF(sys32_syscall)
> +	subu	t0, a0, __NR_O32_Linux		# check syscall number
> +	sltiu	v0, t0, __NR_O32_Linux_syscalls
> +	beqz	t0, einval			# do not recurse
> +	dsll	t1, t0, 3
> +	beqz	v0, einval
> +	ld	t2, sys32_call_table(t1)	# syscall routine
> +
> +	move	a0, a1				# shift argument registers
> +	move	a1, a2
> +	move	a2, a3
> +	move	a3, a4
> +	move	a4, a5
> +	move	a5, a6
> +	move	a6, a7
> +	jr	t2
> +	/* Unreached */
> +
> +einval: li	v0, -ENOSYS
> +	jr	ra
> +	END(sys32_syscall)
> +
> +#define __SYSCALL_WITH_COMPAT(nr, native, compat)	__SYSCALL(nr, compat)
> +#define __SYSCALL(nr, entry)	PTR entry
> +	.align	3
> +	.type	sys32_call_table,@object
> +EXPORT(sys32_call_table)
> +#include <asm/syscall_table_o32.h>
> +#endif /* CONFIG_MIPS32_O32 */
> +
> +#ifdef CONFIG_MIPS32_N32
> +#undef __SYSCALL
> +#define __SYSCALL(nr, entry)	PTR entry
> +	.align	3
> +	.type	sysn32_call_table, @object
> +EXPORT(sysn32_call_table)
> +#include <asm/syscall_table_n32.h>
> +#endif /* CONFIG_MIPS32_N32 */
> +
> +#undef __SYSCALL
> +#define __SYSCALL(nr, entry)	PTR entry
> +	.align	3
> +	.type	sys_call_table, @object
> +EXPORT(sys_call_table)
> +#include <asm/syscall_table_n64.h>
> +#endif /* CONFIG_64BIT */
> diff --git a/arch/mips/kernel/scall32-o32.S b/arch/mips/kernel/scall32-o32.S
> deleted file mode 100644
> index b1b2e106f711..000000000000
> --- a/arch/mips/kernel/scall32-o32.S
> +++ /dev/null
> @@ -1,223 +0,0 @@
> -/*
> - * This file is subject to the terms and conditions of the GNU General Public
> - * License.  See the file "COPYING" in the main directory of this archive
> - * for more details.
> - *
> - * Copyright (C) 1995-99, 2000- 02, 06 Ralf Baechle <ralf@linux-mips.org>
> - * Copyright (C) 2001 MIPS Technologies, Inc.
> - * Copyright (C) 2004 Thiemo Seufer
> - * Copyright (C) 2014 Imagination Technologies Ltd.
> - */
> -#include <linux/errno.h>
> -#include <asm/asm.h>
> -#include <asm/asmmacro.h>
> -#include <asm/irqflags.h>
> -#include <asm/mipsregs.h>
> -#include <asm/regdef.h>
> -#include <asm/stackframe.h>
> -#include <asm/isadep.h>
> -#include <asm/sysmips.h>
> -#include <asm/thread_info.h>
> -#include <asm/unistd.h>
> -#include <asm/war.h>
> -#include <asm/asm-offsets.h>
> -
> -	.align	5
> -NESTED(handle_sys, PT_SIZE, sp)
> -	.set	noat
> -	SAVE_SOME
> -	TRACE_IRQS_ON_RELOAD
> -	STI
> -	.set	at
> -
> -	lw	t1, PT_EPC(sp)		# skip syscall on return
> -
> -	addiu	t1, 4			# skip to next instruction
> -	sw	t1, PT_EPC(sp)
> -
> -	sw	a3, PT_R26(sp)		# save a3 for syscall restarting
> -
> -	/*
> -	 * More than four arguments.  Try to deal with it by copying the
> -	 * stack arguments from the user stack to the kernel stack.
> -	 * This Sucks (TM).
> -	 */
> -	lw	t0, PT_R29(sp)		# get old user stack pointer
> -
> -	/*
> -	 * We intentionally keep the kernel stack a little below the top of
> -	 * userspace so we don't have to do a slower byte accurate check here.
> -	 */
> -	addu	t4, t0, 32
> -	bltz	t4, bad_stack		# -> sp is bad
> -
> -	/*
> -	 * Ok, copy the args from the luser stack to the kernel stack.
> -	 */
> -
> -	.set    push
> -	.set    noreorder
> -	.set	nomacro
> -
> -load_a4: user_lw(t5, 16(t0))		# argument #5 from usp
> -load_a5: user_lw(t6, 20(t0))		# argument #6 from usp
> -load_a6: user_lw(t7, 24(t0))		# argument #7 from usp
> -load_a7: user_lw(t8, 28(t0))		# argument #8 from usp
> -loads_done:
> -
> -	sw	t5, 16(sp)		# argument #5 to ksp
> -	sw	t6, 20(sp)		# argument #6 to ksp
> -	sw	t7, 24(sp)		# argument #7 to ksp
> -	sw	t8, 28(sp)		# argument #8 to ksp
> -	.set	pop
> -
> -	.section __ex_table,"a"
> -	PTR	load_a4, bad_stack_a4
> -	PTR	load_a5, bad_stack_a5
> -	PTR	load_a6, bad_stack_a6
> -	PTR	load_a7, bad_stack_a7
> -	.previous
> -
> -	lw	t0, TI_FLAGS($28)	# syscall tracing enabled?
> -	li	t1, _TIF_WORK_SYSCALL_ENTRY
> -	and	t0, t1
> -	bnez	t0, syscall_trace_entry # -> yes
> -syscall_common:
> -	subu	v0, v0, __NR_O32_Linux	# check syscall number
> -	sltiu	t0, v0, __NR_O32_Linux_syscalls
> -	beqz	t0, illegal_syscall
> -
> -	sll	t0, v0, 2
> -	la	t1, sys_call_table
> -	addu	t1, t0
> -	lw	t2, (t1)		# syscall routine
> -
> -	beqz	t2, illegal_syscall
> -
> -	jalr	t2			# Do The Real Thing (TM)
> -
> -	li	t0, -EMAXERRNO - 1	# error?
> -	sltu	t0, t0, v0
> -	sw	t0, PT_R7(sp)		# set error flag
> -	beqz	t0, 1f
> -
> -	lw	t1, PT_R2(sp)		# syscall number
> -	negu	v0			# error
> -	sw	t1, PT_R0(sp)		# save it for syscall restarting
> -1:	sw	v0, PT_R2(sp)		# result
> -
> -o32_syscall_exit:
> -	j	syscall_exit_partial
> -
> -/* ------------------------------------------------------------------------ */
> -
> -syscall_trace_entry:
> -	SAVE_STATIC
> -	move	a0, sp
> -
> -	/*
> -	 * syscall number is in v0 unless we called syscall(__NR_###)
> -	 * where the real syscall number is in a0
> -	 */
> -	move	a1, v0
> -	subu	t2, v0,  __NR_O32_Linux
> -	bnez	t2, 1f /* __NR_syscall at offset 0 */
> -	lw	a1, PT_R4(sp)
> -
> -1:	jal	syscall_trace_enter
> -
> -	bltz	v0, 1f			# seccomp failed? Skip syscall
> -
> -	RESTORE_STATIC
> -	lw	v0, PT_R2(sp)		# Restore syscall (maybe modified)
> -	lw	a0, PT_R4(sp)		# Restore argument registers
> -	lw	a1, PT_R5(sp)
> -	lw	a2, PT_R6(sp)
> -	lw	a3, PT_R7(sp)
> -	j	syscall_common
> -
> -1:	j	syscall_exit
> -
> -/* ------------------------------------------------------------------------ */
> -
> -	/*
> -	 * Our open-coded access area sanity test for the stack pointer
> -	 * failed. We probably should handle this case a bit more drastic.
> -	 */
> -bad_stack:
> -	li	v0, EFAULT
> -	sw	v0, PT_R2(sp)
> -	li	t0, 1				# set error flag
> -	sw	t0, PT_R7(sp)
> -	j	o32_syscall_exit
> -
> -bad_stack_a4:
> -	li	t5, 0
> -	b	load_a5
> -
> -bad_stack_a5:
> -	li	t6, 0
> -	b	load_a6
> -
> -bad_stack_a6:
> -	li	t7, 0
> -	b	load_a7
> -
> -bad_stack_a7:
> -	li	t8, 0
> -	b	loads_done
> -
> -	/*
> -	 * The system call does not exist in this kernel
> -	 */
> -illegal_syscall:
> -	li	v0, ENOSYS			# error
> -	sw	v0, PT_R2(sp)
> -	li	t0, 1				# set error flag
> -	sw	t0, PT_R7(sp)
> -	j	o32_syscall_exit
> -	END(handle_sys)
> -
> -	LEAF(sys_syscall)
> -	subu	t0, a0, __NR_O32_Linux	# check syscall number
> -	sltiu	v0, t0, __NR_O32_Linux_syscalls
> -	beqz	t0, einval		# do not recurse
> -	sll	t1, t0, 2
> -	beqz	v0, einval
> -	lw	t2, sys_call_table(t1)		# syscall routine
> -
> -	move	a0, a1				# shift argument registers
> -	move	a1, a2
> -	move	a2, a3
> -	lw	a3, 16(sp)
> -	lw	t4, 20(sp)
> -	lw	t5, 24(sp)
> -	lw	t6, 28(sp)
> -	sw	t4, 16(sp)
> -	sw	t5, 20(sp)
> -	sw	t6, 24(sp)
> -	jr	t2
> -	/* Unreached */
> -
> -einval: li	v0, -ENOSYS
> -	jr	ra
> -	END(sys_syscall)
> -
> -#ifdef CONFIG_MIPS_MT_FPAFF
> -	/*
> -	 * For FPU affinity scheduling on MIPS MT processors, we need to
> -	 * intercept sys_sched_xxxaffinity() calls until we get a proper hook
> -	 * in kernel/sched/core.c.  Considered only temporary we only support
> -	 * these hooks for the 32-bit kernel - there is no MIPS64 MT processor
> -	 * atm.
> -	 */
> -#define sys_sched_setaffinity	mipsmt_sys_sched_setaffinity
> -#define sys_sched_getaffinity	mipsmt_sys_sched_getaffinity
> -#endif /* CONFIG_MIPS_MT_FPAFF */
> -
> -#define __SYSCALL_WITH_COMPAT(nr, native, compat)	__SYSCALL(nr, native)
> -#define __SYSCALL(nr, entry) 	PTR entry
> -	.align	2
> -	.type	sys_call_table, @object
> -EXPORT(sys_call_table)
> -#include <asm/syscall_table_o32.h>
> diff --git a/arch/mips/kernel/scall64-n32.S b/arch/mips/kernel/scall64-n32.S
> deleted file mode 100644
> index f650c55a17dc..000000000000
> --- a/arch/mips/kernel/scall64-n32.S
> +++ /dev/null
> @@ -1,107 +0,0 @@
> -/*
> - * This file is subject to the terms and conditions of the GNU General Public
> - * License.  See the file "COPYING" in the main directory of this archive
> - * for more details.
> - *
> - * Copyright (C) 1995, 96, 97, 98, 99, 2000, 01 by Ralf Baechle
> - * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
> - * Copyright (C) 2001 MIPS Technologies, Inc.
> - */
> -#include <linux/errno.h>
> -#include <asm/asm.h>
> -#include <asm/asmmacro.h>
> -#include <asm/irqflags.h>
> -#include <asm/mipsregs.h>
> -#include <asm/regdef.h>
> -#include <asm/stackframe.h>
> -#include <asm/thread_info.h>
> -#include <asm/unistd.h>
> -
> -#ifndef CONFIG_MIPS32_O32
> -/* No O32, so define handle_sys here */
> -#define handle_sysn32 handle_sys
> -#endif
> -
> -	.align	5
> -NESTED(handle_sysn32, PT_SIZE, sp)
> -#ifndef CONFIG_MIPS32_O32
> -	.set	noat
> -	SAVE_SOME
> -	TRACE_IRQS_ON_RELOAD
> -	STI
> -	.set	at
> -#endif
> -
> -	dsubu	t0, v0, __NR_N32_Linux	# check syscall number
> -	sltiu	t0, t0, __NR_N32_Linux_syscalls
> -
> -#ifndef CONFIG_MIPS32_O32
> -	ld	t1, PT_EPC(sp)		# skip syscall on return
> -	daddiu	t1, 4			# skip to next instruction
> -	sd	t1, PT_EPC(sp)
> -#endif
> -	beqz	t0, not_n32_scall
> -
> -	sd	a3, PT_R26(sp)		# save a3 for syscall restarting
> -
> -	li	t1, _TIF_WORK_SYSCALL_ENTRY
> -	LONG_L	t0, TI_FLAGS($28)	# syscall tracing enabled?
> -	and	t0, t1, t0
> -	bnez	t0, n32_syscall_trace_entry
> -
> -syscall_common:
> -	dsll	t0, v0, 3		# offset into table
> -	ld	t2, (sysn32_call_table - (__NR_N32_Linux * 8))(t0)
> -
> -	jalr	t2			# Do The Real Thing (TM)
> -
> -	li	t0, -EMAXERRNO - 1	# error?
> -	sltu	t0, t0, v0
> -	sd	t0, PT_R7(sp)		# set error flag
> -	beqz	t0, 1f
> -
> -	ld	t1, PT_R2(sp)		# syscall number
> -	dnegu	v0			# error
> -	sd	t1, PT_R0(sp)		# save it for syscall restarting
> -1:	sd	v0, PT_R2(sp)		# result
> -
> -	j	syscall_exit_partial
> -
> -/* ------------------------------------------------------------------------ */
> -
> -n32_syscall_trace_entry:
> -	SAVE_STATIC
> -	move	a0, sp
> -	move	a1, v0
> -	jal	syscall_trace_enter
> -
> -	bltz	v0, 1f			# seccomp failed? Skip syscall
> -
> -	RESTORE_STATIC
> -	ld	v0, PT_R2(sp)		# Restore syscall (maybe modified)
> -	ld	a0, PT_R4(sp)		# Restore argument registers
> -	ld	a1, PT_R5(sp)
> -	ld	a2, PT_R6(sp)
> -	ld	a3, PT_R7(sp)
> -	ld	a4, PT_R8(sp)
> -	ld	a5, PT_R9(sp)
> -
> -	dsubu	t2, v0, __NR_N32_Linux	# check (new) syscall number
> -	sltiu   t0, t2, __NR_N32_Linux_syscalls
> -	beqz	t0, not_n32_scall
> -
> -	j	syscall_common
> -
> -1:	j	syscall_exit
> -
> -not_n32_scall:
> -	/* This is not an n32 compatibility syscall, pass it on to
> -	   the n64 syscall handlers.  */
> -	j	handle_sys64
> -
> -	END(handle_sysn32)
> -
> -#define __SYSCALL(nr, entry)	PTR entry
> -	.type	sysn32_call_table, @object
> -EXPORT(sysn32_call_table)
> -#include <asm/syscall_table_n32.h>
> diff --git a/arch/mips/kernel/scall64-n64.S b/arch/mips/kernel/scall64-n64.S
> deleted file mode 100644
> index 5d7bfc65e4d0..000000000000
> --- a/arch/mips/kernel/scall64-n64.S
> +++ /dev/null
> @@ -1,116 +0,0 @@
> -/*
> - * This file is subject to the terms and conditions of the GNU General Public
> - * License.  See the file "COPYING" in the main directory of this archive
> - * for more details.
> - *
> - * Copyright (C) 1995, 96, 97, 98, 99, 2000, 01, 02 by Ralf Baechle
> - * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
> - * Copyright (C) 2001 MIPS Technologies, Inc.
> - */
> -#include <linux/errno.h>
> -#include <asm/asm.h>
> -#include <asm/asmmacro.h>
> -#include <asm/irqflags.h>
> -#include <asm/mipsregs.h>
> -#include <asm/regdef.h>
> -#include <asm/stackframe.h>
> -#include <asm/asm-offsets.h>
> -#include <asm/sysmips.h>
> -#include <asm/thread_info.h>
> -#include <asm/unistd.h>
> -#include <asm/war.h>
> -
> -#ifndef CONFIG_MIPS32_COMPAT
> -/* Neither O32 nor N32, so define handle_sys here */
> -#define handle_sys64 handle_sys
> -#endif
> -
> -	.align	5
> -NESTED(handle_sys64, PT_SIZE, sp)
> -#if !defined(CONFIG_MIPS32_O32) && !defined(CONFIG_MIPS32_N32)
> -	/*
> -	 * When 32-bit compatibility is configured scall_o32.S
> -	 * already did this.
> -	 */
> -	.set	noat
> -	SAVE_SOME
> -	TRACE_IRQS_ON_RELOAD
> -	STI
> -	.set	at
> -#endif
> -
> -#if !defined(CONFIG_MIPS32_O32) && !defined(CONFIG_MIPS32_N32)
> -	ld	t1, PT_EPC(sp)		# skip syscall on return
> -	daddiu	t1, 4			# skip to next instruction
> -	sd	t1, PT_EPC(sp)
> -#endif
> -
> -	sd	a3, PT_R26(sp)		# save a3 for syscall restarting
> -
> -	li	t1, _TIF_WORK_SYSCALL_ENTRY
> -	LONG_L	t0, TI_FLAGS($28)	# syscall tracing enabled?
> -	and	t0, t1, t0
> -	bnez	t0, syscall_trace_entry
> -
> -syscall_common:
> -	dsubu	t2, v0, __NR_64_Linux
> -	sltiu   t0, t2, __NR_64_Linux_syscalls
> -	beqz	t0, illegal_syscall
> -
> -	dsll	t0, t2, 3		# offset into table
> -	dla	t2, sys_call_table
> -	daddu	t0, t2, t0
> -	ld	t2, (t0)		# syscall routine
> -	beqz	t2, illegal_syscall
> -
> -	jalr	t2			# Do The Real Thing (TM)
> -
> -	li	t0, -EMAXERRNO - 1	# error?
> -	sltu	t0, t0, v0
> -	sd	t0, PT_R7(sp)		# set error flag
> -	beqz	t0, 1f
> -
> -	ld	t1, PT_R2(sp)		# syscall number
> -	dnegu	v0			# error
> -	sd	t1, PT_R0(sp)		# save it for syscall restarting
> -1:	sd	v0, PT_R2(sp)		# result
> -
> -n64_syscall_exit:
> -	j	syscall_exit_partial
> -
> -/* ------------------------------------------------------------------------ */
> -
> -syscall_trace_entry:
> -	SAVE_STATIC
> -	move	a0, sp
> -	move	a1, v0
> -	jal	syscall_trace_enter
> -
> -	bltz	v0, 1f			# seccomp failed? Skip syscall
> -
> -	RESTORE_STATIC
> -	ld	v0, PT_R2(sp)		# Restore syscall (maybe modified)
> -	ld	a0, PT_R4(sp)		# Restore argument registers
> -	ld	a1, PT_R5(sp)
> -	ld	a2, PT_R6(sp)
> -	ld	a3, PT_R7(sp)
> -	ld	a4, PT_R8(sp)
> -	ld	a5, PT_R9(sp)
> -	j	syscall_common
> -
> -1:	j	syscall_exit
> -
> -illegal_syscall:
> -	/* This also isn't a 64-bit syscall, throw an error.  */
> -	li	v0, ENOSYS			# error
> -	sd	v0, PT_R2(sp)
> -	li	t0, 1				# set error flag
> -	sd	t0, PT_R7(sp)
> -	j	n64_syscall_exit
> -	END(handle_sys64)
> -
> -#define __SYSCALL(nr, entry)	PTR entry
> -	.align	3
> -	.type	sys_call_table, @object
> -EXPORT(sys_call_table)
> -#include <asm/syscall_table_n64.h>
> diff --git a/arch/mips/kernel/scall64-o32.S b/arch/mips/kernel/scall64-o32.S
> deleted file mode 100644
> index cedc8bd88804..000000000000
> --- a/arch/mips/kernel/scall64-o32.S
> +++ /dev/null
> @@ -1,221 +0,0 @@
> -/*
> - * This file is subject to the terms and conditions of the GNU General Public
> - * License.  See the file "COPYING" in the main directory of this archive
> - * for more details.
> - *
> - * Copyright (C) 1995 - 2000, 2001 by Ralf Baechle
> - * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
> - * Copyright (C) 2001 MIPS Technologies, Inc.
> - * Copyright (C) 2004 Thiemo Seufer
> - *
> - * Hairy, the userspace application uses a different argument passing
> - * convention than the kernel, so we have to translate things from o32
> - * to ABI64 calling convention.	 64-bit syscalls are also processed
> - * here for now.
> - */
> -#include <linux/errno.h>
> -#include <asm/asm.h>
> -#include <asm/asmmacro.h>
> -#include <asm/irqflags.h>
> -#include <asm/mipsregs.h>
> -#include <asm/regdef.h>
> -#include <asm/stackframe.h>
> -#include <asm/thread_info.h>
> -#include <asm/unistd.h>
> -#include <asm/sysmips.h>
> -
> -	.align	5
> -NESTED(handle_sys, PT_SIZE, sp)
> -	.set	noat
> -	SAVE_SOME
> -	TRACE_IRQS_ON_RELOAD
> -	STI
> -	.set	at
> -	ld	t1, PT_EPC(sp)		# skip syscall on return
> -
> -	dsubu	t0, v0, __NR_O32_Linux	# check syscall number
> -	sltiu	t0, t0, __NR_O32_Linux_syscalls
> -	daddiu	t1, 4			# skip to next instruction
> -	sd	t1, PT_EPC(sp)
> -	beqz	t0, not_o32_scall
> -#if 0
> - SAVE_ALL
> - move a1, v0
> - ASM_PRINT("Scall %ld\n")
> - RESTORE_ALL
> -#endif
> -
> -	/* We don't want to stumble over broken sign extensions from
> -	   userland. O32 does never use the upper half. */
> -	sll	a0, a0, 0
> -	sll	a1, a1, 0
> -	sll	a2, a2, 0
> -	sll	a3, a3, 0
> -
> -	sd	a3, PT_R26(sp)		# save a3 for syscall restarting
> -
> -	/*
> -	 * More than four arguments.  Try to deal with it by copying the
> -	 * stack arguments from the user stack to the kernel stack.
> -	 * This Sucks (TM).
> -	 *
> -	 * We intentionally keep the kernel stack a little below the top of
> -	 * userspace so we don't have to do a slower byte accurate check here.
> -	 */
> -	ld	t0, PT_R29(sp)		# get old user stack pointer
> -	daddu	t1, t0, 32
> -	bltz	t1, bad_stack
> -
> -load_a4: lw	a4, 16(t0)		# argument #5 from usp
> -load_a5: lw	a5, 20(t0)		# argument #6 from usp
> -load_a6: lw	a6, 24(t0)		# argument #7 from usp
> -load_a7: lw	a7, 28(t0)		# argument #8 from usp
> -loads_done:
> -
> -	.section __ex_table,"a"
> -	PTR	load_a4, bad_stack_a4
> -	PTR	load_a5, bad_stack_a5
> -	PTR	load_a6, bad_stack_a6
> -	PTR	load_a7, bad_stack_a7
> -	.previous
> -
> -	li	t1, _TIF_WORK_SYSCALL_ENTRY
> -	LONG_L	t0, TI_FLAGS($28)	# syscall tracing enabled?
> -	and	t0, t1, t0
> -	bnez	t0, trace_a_syscall
> -
> -syscall_common:
> -	dsll	t0, v0, 3		# offset into table
> -	ld	t2, (sys32_call_table - (__NR_O32_Linux * 8))(t0)
> -
> -	jalr	t2			# Do The Real Thing (TM)
> -
> -	li	t0, -EMAXERRNO - 1	# error?
> -	sltu	t0, t0, v0
> -	sd	t0, PT_R7(sp)		# set error flag
> -	beqz	t0, 1f
> -
> -	ld	t1, PT_R2(sp)		# syscall number
> -	dnegu	v0			# error
> -	sd	t1, PT_R0(sp)		# save it for syscall restarting
> -1:	sd	v0, PT_R2(sp)		# result
> -
> -o32_syscall_exit:
> -	j	syscall_exit_partial
> -
> -/* ------------------------------------------------------------------------ */
> -
> -trace_a_syscall:
> -	SAVE_STATIC
> -	sd	a4, PT_R8(sp)		# Save argument registers
> -	sd	a5, PT_R9(sp)
> -	sd	a6, PT_R10(sp)
> -	sd	a7, PT_R11(sp)		# For indirect syscalls
> -
> -	move	a0, sp
> -	/*
> -	 * absolute syscall number is in v0 unless we called syscall(__NR_###)
> -	 * where the real syscall number is in a0
> -	 * note: NR_syscall is the first O32 syscall but the macro is
> -	 * only defined when compiling with -mabi=32 (CONFIG_32BIT)
> -	 * therefore __NR_O32_Linux is used (4000)
> -	 */
> -	.set	push
> -	.set	reorder
> -	subu	t1, v0,  __NR_O32_Linux
> -	move	a1, v0
> -	bnez	t1, 1f /* __NR_syscall at offset 0 */
> -	ld	a1, PT_R4(sp) /* Arg1 for __NR_syscall case */
> -	.set	pop
> -
> -1:	jal	syscall_trace_enter
> -
> -	bltz	v0, 1f			# seccomp failed? Skip syscall
> -
> -	RESTORE_STATIC
> -	ld	v0, PT_R2(sp)		# Restore syscall (maybe modified)
> -	ld	a0, PT_R4(sp)		# Restore argument registers
> -	ld	a1, PT_R5(sp)
> -	ld	a2, PT_R6(sp)
> -	ld	a3, PT_R7(sp)
> -	ld	a4, PT_R8(sp)
> -	ld	a5, PT_R9(sp)
> -	ld	a6, PT_R10(sp)
> -	ld	a7, PT_R11(sp)		# For indirect syscalls
> -
> -	dsubu	t0, v0, __NR_O32_Linux	# check (new) syscall number
> -	sltiu	t0, t0, __NR_O32_Linux_syscalls
> -	beqz	t0, not_o32_scall
> -
> -	j	syscall_common
> -
> -1:	j	syscall_exit
> -
> -/* ------------------------------------------------------------------------ */
> -
> -	/*
> -	 * The stackpointer for a call with more than 4 arguments is bad.
> -	 */
> -bad_stack:
> -	li	v0, EFAULT
> -	sd	v0, PT_R2(sp)
> -	li	t0, 1			# set error flag
> -	sd	t0, PT_R7(sp)
> -	j	o32_syscall_exit
> -
> -bad_stack_a4:
> -	li	a4, 0
> -	b	load_a5
> -
> -bad_stack_a5:
> -	li	a5, 0
> -	b	load_a6
> -
> -bad_stack_a6:
> -	li	a6, 0
> -	b	load_a7
> -
> -bad_stack_a7:
> -	li	a7, 0
> -	b	loads_done
> -
> -not_o32_scall:
> -	/*
> -	 * This is not an o32 compatibility syscall, pass it on
> -	 * to the 64-bit syscall handlers.
> -	 */
> -#ifdef CONFIG_MIPS32_N32
> -	j	handle_sysn32
> -#else
> -	j	handle_sys64
> -#endif
> -	END(handle_sys)
> -
> -LEAF(sys32_syscall)
> -	subu	t0, a0, __NR_O32_Linux	# check syscall number
> -	sltiu	v0, t0, __NR_O32_Linux_syscalls
> -	beqz	t0, einval		# do not recurse
> -	dsll	t1, t0, 3
> -	beqz	v0, einval
> -	ld	t2, sys32_call_table(t1)		# syscall routine
> -
> -	move	a0, a1			# shift argument registers
> -	move	a1, a2
> -	move	a2, a3
> -	move	a3, a4
> -	move	a4, a5
> -	move	a5, a6
> -	move	a6, a7
> -	jr	t2
> -	/* Unreached */
> -
> -einval: li	v0, -ENOSYS
> -	jr	ra
> -	END(sys32_syscall)
> -
> -#define __SYSCALL_WITH_COMPAT(nr, native, compat)	__SYSCALL(nr, compat)
> -#define __SYSCALL(nr, entry)	PTR entry
> -	.align	3
> -	.type	sys32_call_table,@object
> -EXPORT(sys32_call_table)
> -#include <asm/syscall_table_o32.h>
> diff --git a/arch/mips/kernel/signal.c b/arch/mips/kernel/signal.c
> index f1e985109da0..1ec6a0cf1163 100644
> --- a/arch/mips/kernel/signal.c
> +++ b/arch/mips/kernel/signal.c
> @@ -32,7 +32,6 @@
>   #include <linux/bitops.h>
>   #include <asm/cacheflush.h>
>   #include <asm/fpu.h>
> -#include <asm/sim.h>
>   #include <asm/ucontext.h>
>   #include <asm/cpu-features.h>
>   #include <asm/war.h>
> @@ -627,7 +626,7 @@ SYSCALL_DEFINE3(sigaction, int, sig, const struct sigaction __user *, act,
>   #endif
>   
>   #ifdef CONFIG_TRAD_SIGNALS
> -asmlinkage void sys_sigreturn(void)
> +asmlinkage long sys_sigreturn(void)
>   {
>   	struct sigframe __user *frame;
>   	struct pt_regs *regs;
> @@ -649,22 +648,16 @@ asmlinkage void sys_sigreturn(void)
>   	else if (sig)
>   		force_sig(sig);
>   
> -	/*
> -	 * Don't let your children do this ...
> -	 */
> -	__asm__ __volatile__(
> -		"move\t$29, %0\n\t"
> -		"j\tsyscall_exit"
> -		: /* no outputs */
> -		: "r" (regs));
> -	/* Unreached */
> +	regs->regs[27] = 1;	/* return directly */
> +	return regs->regs[2];
>   
>   badframe:
>   	force_sig(SIGSEGV);
> +	return 0;
>   }
>   #endif /* CONFIG_TRAD_SIGNALS */
>   
> -asmlinkage void sys_rt_sigreturn(void)
> +asmlinkage long sys_rt_sigreturn(void)
>   {
>   	struct rt_sigframe __user *frame;
>   	struct pt_regs *regs;
> @@ -689,18 +682,12 @@ asmlinkage void sys_rt_sigreturn(void)
>   	if (restore_altstack(&frame->rs_uc.uc_stack))
>   		goto badframe;
>   
> -	/*
> -	 * Don't let your children do this ...
> -	 */
> -	__asm__ __volatile__(
> -		"move\t$29, %0\n\t"
> -		"j\tsyscall_exit"
> -		: /* no outputs */
> -		: "r" (regs));
> -	/* Unreached */
> +	regs->regs[27] = 1;	/* return directly */
> +	return regs->regs[2];
>   
>   badframe:
>   	force_sig(SIGSEGV);
> +	return 0;
>   }
>   
>   #ifdef CONFIG_TRAD_SIGNALS
> @@ -852,11 +839,11 @@ static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
>   	signal_setup_done(ret, ksig, 0);
>   }
>   
> -static void do_signal(struct pt_regs *regs)
> +void arch_do_signal_or_restart(struct pt_regs *regs, bool has_signal)
>   {
>   	struct ksignal ksig;
>   
> -	if (get_signal(&ksig)) {
> +	if (has_signal && get_signal(&ksig)) {
>   		/* Whee!  Actually deliver the signal.	*/
>   		handle_signal(&ksig, regs);
>   		return;
> @@ -904,7 +891,7 @@ asmlinkage void do_notify_resume(struct pt_regs *regs, void *unused,
>   
>   	/* deal with pending signal delivery */
>   	if (thread_info_flags & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL))
> -		do_signal(regs);
> +		arch_do_signal_or_restart(regs, thread_info_flags & _TIF_SIGPENDING);
>   
>   	if (thread_info_flags & _TIF_NOTIFY_RESUME) {
>   		tracehook_notify_resume(regs);
> diff --git a/arch/mips/kernel/signal_n32.c b/arch/mips/kernel/signal_n32.c
> index 7bd00fad61af..b52b995a8a9b 100644
> --- a/arch/mips/kernel/signal_n32.c
> +++ b/arch/mips/kernel/signal_n32.c
> @@ -19,7 +19,6 @@
>   #include <asm/asm.h>
>   #include <asm/cacheflush.h>
>   #include <asm/compat-signal.h>
> -#include <asm/sim.h>
>   #include <linux/uaccess.h>
>   #include <asm/ucontext.h>
>   #include <asm/fpu.h>
> @@ -51,7 +50,7 @@ struct rt_sigframe_n32 {
>   	struct ucontextn32 rs_uc;
>   };
>   
> -asmlinkage void sysn32_rt_sigreturn(void)
> +asmlinkage long sysn32_rt_sigreturn(void)
>   {
>   	struct rt_sigframe_n32 __user *frame;
>   	struct pt_regs *regs;
> @@ -76,18 +75,12 @@ asmlinkage void sysn32_rt_sigreturn(void)
>   	if (compat_restore_altstack(&frame->rs_uc.uc_stack))
>   		goto badframe;
>   
> -	/*
> -	 * Don't let your children do this ...
> -	 */
> -	__asm__ __volatile__(
> -		"move\t$29, %0\n\t"
> -		"j\tsyscall_exit"
> -		: /* no outputs */
> -		: "r" (regs));
> -	/* Unreached */
> +	regs->regs[27] = 1;	/* return directly */
> +	return regs->regs[2];
>   
>   badframe:
>   	force_sig(SIGSEGV);
> +	return 0;
>   }
>   
>   static int setup_rt_frame_n32(void *sig_return, struct ksignal *ksig,
> diff --git a/arch/mips/kernel/signal_o32.c b/arch/mips/kernel/signal_o32.c
> index 299a7a28ca33..9245806e06f1 100644
> --- a/arch/mips/kernel/signal_o32.c
> +++ b/arch/mips/kernel/signal_o32.c
> @@ -17,7 +17,6 @@
>   #include <asm/abi.h>
>   #include <asm/compat-signal.h>
>   #include <asm/dsp.h>
> -#include <asm/sim.h>
>   #include <asm/unistd.h>
>   
>   #include "signal-common.h"
> @@ -151,7 +150,7 @@ static int setup_frame_32(void *sig_return, struct ksignal *ksig,
>   	return 0;
>   }
>   
> -asmlinkage void sys32_rt_sigreturn(void)
> +asmlinkage long sys32_rt_sigreturn(void)
>   {
>   	struct rt_sigframe32 __user *frame;
>   	struct pt_regs *regs;
> @@ -176,18 +175,12 @@ asmlinkage void sys32_rt_sigreturn(void)
>   	if (compat_restore_altstack(&frame->rs_uc.uc_stack))
>   		goto badframe;
>   
> -	/*
> -	 * Don't let your children do this ...
> -	 */
> -	__asm__ __volatile__(
> -		"move\t$29, %0\n\t"
> -		"j\tsyscall_exit"
> -		: /* no outputs */
> -		: "r" (regs));
> -	/* Unreached */
> +	regs->regs[27] = 1;	/* return directly */
> +	return regs->regs[2];
>   
>   badframe:
>   	force_sig(SIGSEGV);
> +	return 0;
>   }
>   
>   static int setup_rt_frame_32(void *sig_return, struct ksignal *ksig,
> @@ -253,7 +246,7 @@ struct mips_abi mips_abi_32 = {
>   };
>   
>   
> -asmlinkage void sys32_sigreturn(void)
> +asmlinkage long sys32_sigreturn(void)
>   {
>   	struct sigframe32 __user *frame;
>   	struct pt_regs *regs;
> @@ -275,16 +268,10 @@ asmlinkage void sys32_sigreturn(void)
>   	else if (sig)
>   		force_sig(sig);
>   
> -	/*
> -	 * Don't let your children do this ...
> -	 */
> -	__asm__ __volatile__(
> -		"move\t$29, %0\n\t"
> -		"j\tsyscall_exit"
> -		: /* no outputs */
> -		: "r" (regs));
> -	/* Unreached */
> +	regs->regs[27] = 1;	/* return directly */
> +	return regs->regs[2];
>   
>   badframe:
>   	force_sig(SIGSEGV);
> +	return 0;
>   }
> diff --git a/arch/mips/kernel/syscall.c b/arch/mips/kernel/syscall.c
> index 2afa3eef486a..6dc78648b274 100644
> --- a/arch/mips/kernel/syscall.c
> +++ b/arch/mips/kernel/syscall.c
> @@ -8,6 +8,7 @@
>    * Copyright (C) 2001 MIPS Technologies, Inc.
>    */
>   #include <linux/capability.h>
> +#include <linux/entry-common.h>
>   #include <linux/errno.h>
>   #include <linux/linkage.h>
>   #include <linux/fs.h>
> @@ -35,9 +36,9 @@
>   #include <asm/cacheflush.h>
>   #include <asm/asm-offsets.h>
>   #include <asm/signal.h>
> -#include <asm/sim.h>
>   #include <asm/shmparam.h>
>   #include <asm/sync.h>
> +#include <asm/syscall.h>
>   #include <asm/sysmips.h>
>   #include <asm/switch_to.h>
>   
> @@ -79,10 +80,6 @@ SYSCALL_DEFINE6(mips_mmap2, unsigned long, addr, unsigned long, len,
>   			       pgoff >> (PAGE_SHIFT - 12));
>   }
>   
> -save_static_function(sys_fork);
> -save_static_function(sys_clone);
> -save_static_function(sys_clone3);
> -
>   SYSCALL_DEFINE1(set_thread_area, unsigned long, addr)
>   {
>   	struct thread_info *ti = task_thread_info(current);
> @@ -182,28 +179,11 @@ static inline int mips_atomic_set(unsigned long addr, unsigned long new)
>   		return err;
>   
>   	regs = current_pt_regs();
> -	regs->regs[2] = old;
> -	regs->regs[7] = 0;	/* No error */
> -
> -	/*
> -	 * Don't let your children do this ...
> -	 */
> -	__asm__ __volatile__(
> -	"	move	$29, %0						\n"
> -	"	j	syscall_exit					\n"
> -	: /* no outputs */
> -	: "r" (regs));
> -
> -	/* unreached.  Honestly.  */
> -	unreachable();
> +	regs->regs[7] = 0;	/* no error */
> +	regs->regs[27] = 1;	/* return directly */
> +	return old;
>   }
>   
> -/*
> - * mips_atomic_set() normally returns directly via syscall_exit potentially
> - * clobbering static registers, so be sure to preserve them.
> - */
> -save_static_function(sys_sysmips);
> -
>   SYSCALL_DEFINE3(sysmips, long, cmd, long, arg1, long, arg2)
>   {
>   	switch (cmd) {
> @@ -249,3 +229,120 @@ asmlinkage void bad_stack(void)
>   {
>   	do_exit(SIGSEGV);
>   }
> +
> +#if defined(CONFIG_32BIT) || defined(CONFIG_MIPS32_O32)
> +static inline int get_args(struct pt_regs *regs)
> +{
> +	int *usp = (int *)regs->regs[29];
> +
> +#ifdef CONFIG_MIPS32_O32
> +	/*
> +	 * Hairy, the userspace application uses a different argument passing
> +	 * convention than the kernel, so we have to translate things from o32
> +	 * to ABI64 calling convention.
> +	 *
> +	 * We don't want to stumble over broken sign extensions from userland.
> +	 * O32 does never use the upper half.
> +	 */
> +	regs->regs[4] = (int)regs->regs[4];
> +	regs->regs[5] = (int)regs->regs[5];
> +	regs->regs[6] = (int)regs->regs[6];
> +	regs->regs[7] = (int)regs->regs[7];
> +#endif
> +
> +	/*
> +	 * More than four arguments.  Try to deal with it by copying the
> +	 * stack arguments from the user stack to the kernel stack.
> +	 * This Sucks (TM).
> +	 *
> +	 * We intentionally keep the kernel stack a little below the top of
> +	 * userspace so we don't have to do a slower byte accurate check here.
> +	 */
> +	if (!access_ok(usp, 32))
> +		return -1;
> +
> +	get_user(regs->regs[8], usp + 4);
> +	get_user(regs->regs[9], usp + 5);
> +	get_user(regs->regs[10], usp + 6);
> +	get_user(regs->regs[11], usp + 7);
> +
> +	return 0;
> +}
> +#endif
> +
> +typedef long (*sys_call_fn)(unsigned long, unsigned long,
> +	unsigned long, unsigned long, unsigned long, unsigned long);
> +
> +void noinstr do_syscall(struct pt_regs *regs)
> +{
> +	unsigned long nr;
> +	unsigned long ret;
> +	sys_call_fn syscall_fn = NULL;
> +
> +	nr = regs->regs[2];
> +	current_thread_info()->syscall = nr;
> +	nr = syscall_enter_from_user_mode(regs, nr);
> +
> +	regs->cp0_epc += 4;		/* skip syscall on return */
> +					/* skip to next instruction */
> +	regs->regs[26] = regs->regs[7];	/* save a3 for syscall restarting */
> +	regs->regs[27] = 0;		/* do not return directly */
> +
> +#ifdef CONFIG_32BIT
> +	if (nr >= __NR_O32_Linux && nr < __NR_O32_Linux + __NR_O32_Linux_syscalls) {
> +		if (get_args(regs) < 0) {
> +			ret = EFAULT;
> +			goto error;
> +		}
> +		syscall_fn = (sys_call_fn)sys_call_table[nr - __NR_O32_Linux];
> +	}
> +#endif
> +
> +#ifdef CONFIG_MIPS32_O32
> +	if (nr >= __NR_O32_Linux && nr < __NR_O32_Linux + __NR_O32_Linux_syscalls) {
> +		if (get_args(regs) < 0) {
> +			ret = EFAULT;
> +			goto error;
> +		}
> +		syscall_fn = (sys_call_fn)sys32_call_table[nr - __NR_O32_Linux];
> +	}
> +#endif
> +
> +#ifdef CONFIG_MIPS32_N32
> +	if (nr >= __NR_N32_Linux && nr < __NR_N32_Linux + __NR_N32_Linux_syscalls)
> +		syscall_fn = (sys_call_fn)sysn32_call_table[nr - __NR_N32_Linux];
> +#endif
> +
> +#ifdef CONFIG_64BIT
> +	if (nr >= __NR_64_Linux && nr < __NR_64_Linux + __NR_64_Linux_syscalls)
> +		syscall_fn = (sys_call_fn)sys_call_table[nr - __NR_64_Linux];
> +#endif
> +
> +	if (!syscall_fn) {
> +		ret = ENOSYS;
> +		goto error;
> +	}
> +
> +	ret = syscall_fn(regs->regs[4], regs->regs[5], regs->regs[6],
> +			 regs->regs[7], regs->regs[8], regs->regs[9]);
> +
> +	if (regs->regs[27])		/* return directly? */
> +		goto out;
> +
> +	regs->regs[7] = 0;		/* clear error flag */
> +	if (ret >= -EMAXERRNO - 1) {	/* error? */
> +		regs->regs[0] = nr;	/* save syscall number */
> +					/* for syscall restarting */
> +		ret = -ret;
> +		goto error;
> +	}
> +
> +	goto out;
> +
> +error:
> +	regs->regs[7] = 1;		/* set error flag */
> +
> +out:
> +	regs->regs[2] = ret;
> +	syscall_exit_to_user_mode(regs);
> +}
> diff --git a/arch/mips/kernel/syscalls/syscall_n32.tbl b/arch/mips/kernel/syscalls/syscall_n32.tbl
> index 70e32de2bcaa..d9ae765e51f1 100644
> --- a/arch/mips/kernel/syscalls/syscall_n32.tbl
> +++ b/arch/mips/kernel/syscalls/syscall_n32.tbl
> @@ -62,8 +62,8 @@
>   52	n32	socketpair			sys_socketpair
>   53	n32	setsockopt			sys_setsockopt
>   54	n32	getsockopt			sys_getsockopt
> -55	n32	clone				__sys_clone
> -56	n32	fork				__sys_fork
> +55	n32	clone				sys_clone
> +56	n32	fork				sys_fork
>   57	n32	execve				compat_sys_execve
>   58	n32	exit				sys_exit
>   59	n32	wait4				compat_sys_wait4
> @@ -207,7 +207,7 @@
>   196	n32	sched_getaffinity		compat_sys_sched_getaffinity
>   197	n32	cacheflush			sys_cacheflush
>   198	n32	cachectl			sys_cachectl
> -199	n32	sysmips				__sys_sysmips
> +199	n32	sysmips				sys_sysmips
>   200	n32	io_setup			compat_sys_io_setup
>   201	n32	io_destroy			sys_io_destroy
>   202	n32	io_getevents			sys_io_getevents_time32
> @@ -373,7 +373,7 @@
>   432	n32	fsmount				sys_fsmount
>   433	n32	fspick				sys_fspick
>   434	n32	pidfd_open			sys_pidfd_open
> -435	n32	clone3				__sys_clone3
> +435	n32	clone3				sys_clone3
>   436	n32	close_range			sys_close_range
>   437	n32	openat2				sys_openat2
>   438	n32	pidfd_getfd			sys_pidfd_getfd
> diff --git a/arch/mips/kernel/syscalls/syscall_n64.tbl b/arch/mips/kernel/syscalls/syscall_n64.tbl
> index 1ca7bc337932..edec3e82d67a 100644
> --- a/arch/mips/kernel/syscalls/syscall_n64.tbl
> +++ b/arch/mips/kernel/syscalls/syscall_n64.tbl
> @@ -62,8 +62,8 @@
>   52	n64	socketpair			sys_socketpair
>   53	n64	setsockopt			sys_setsockopt
>   54	n64	getsockopt			sys_getsockopt
> -55	n64	clone				__sys_clone
> -56	n64	fork				__sys_fork
> +55	n64	clone				sys_clone
> +56	n64	fork				sys_fork
>   57	n64	execve				sys_execve
>   58	n64	exit				sys_exit
>   59	n64	wait4				sys_wait4
> @@ -207,7 +207,7 @@
>   196	n64	sched_getaffinity		sys_sched_getaffinity
>   197	n64	cacheflush			sys_cacheflush
>   198	n64	cachectl			sys_cachectl
> -199	n64	sysmips				__sys_sysmips
> +199	n64	sysmips				sys_sysmips
>   200	n64	io_setup			sys_io_setup
>   201	n64	io_destroy			sys_io_destroy
>   202	n64	io_getevents			sys_io_getevents
> @@ -349,7 +349,7 @@
>   432	n64	fsmount				sys_fsmount
>   433	n64	fspick				sys_fspick
>   434	n64	pidfd_open			sys_pidfd_open
> -435	n64	clone3				__sys_clone3
> +435	n64	clone3				sys_clone3
>   436	n64	close_range			sys_close_range
>   437	n64	openat2				sys_openat2
>   438	n64	pidfd_getfd			sys_pidfd_getfd
> diff --git a/arch/mips/kernel/syscalls/syscall_o32.tbl b/arch/mips/kernel/syscalls/syscall_o32.tbl
> index a61c35edaa74..89a1f267da6a 100644
> --- a/arch/mips/kernel/syscalls/syscall_o32.tbl
> +++ b/arch/mips/kernel/syscalls/syscall_o32.tbl
> @@ -9,7 +9,7 @@
>   #
>   0	o32	syscall				sys_syscall			sys32_syscall
>   1	o32	exit				sys_exit
> -2	o32	fork				__sys_fork
> +2	o32	fork				sys_fork
>   3	o32	read				sys_read
>   4	o32	write				sys_write
>   5	o32	open				sys_open			compat_sys_open
> @@ -131,7 +131,7 @@
>   117	o32	ipc				sys_ipc				compat_sys_ipc
>   118	o32	fsync				sys_fsync
>   119	o32	sigreturn			sys_sigreturn			sys32_sigreturn
> -120	o32	clone				__sys_clone
> +120	o32	clone				sys_clone
>   121	o32	setdomainname			sys_setdomainname
>   122	o32	uname				sys_newuname
>   123	o32	modify_ldt			sys_ni_syscall
> @@ -160,7 +160,7 @@
>   146	o32	writev				sys_writev
>   147	o32	cacheflush			sys_cacheflush
>   148	o32	cachectl			sys_cachectl
> -149	o32	sysmips				__sys_sysmips
> +149	o32	sysmips				sys_sysmips
>   150	o32	unused150			sys_ni_syscall
>   151	o32	getsid				sys_getsid
>   152	o32	fdatasync			sys_fdatasync
> @@ -422,7 +422,7 @@
>   432	o32	fsmount				sys_fsmount
>   433	o32	fspick				sys_fspick
>   434	o32	pidfd_open			sys_pidfd_open
> -435	o32	clone3				__sys_clone3
> +435	o32	clone3				sys_clone3
>   436	o32	close_range			sys_close_range
>   437	o32	openat2				sys_openat2
>   438	o32	pidfd_getfd			sys_pidfd_getfd

^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: [PATCH 1/2] mips: convert syscall to generic entry
  2021-09-07 13:48   ` Jiaxun Yang
@ 2021-09-08  2:08     ` 陈飞扬
  2021-09-08  7:15       ` Huacai Chen
  2021-09-08  8:51       ` Thomas Bogendoerfer
  0 siblings, 2 replies; 15+ messages in thread
From: 陈飞扬 @ 2021-09-08  2:08 UTC (permalink / raw)
  To: Jiaxun Yang
  Cc: tsbogend, tglx, peterz, luto, arnd, Feiyang Chen, linux-mips,
	linux-arch, chenhuacai, Yanteng Si

On Tue, 7 Sept 2021 at 21:49, Jiaxun Yang <jiaxun.yang@flygoat.com> wrote:
>
>
> 在 2021/9/7 14:16, FreeFlyingSheep 写道:
> > From: Feiyang Chen <chenfeiyang@loongson.cn>
> >
> > Convert mips syscall to use the generic entry infrastructure from
> > kernel/entry/*.
> >
> > There are a few special things on mips:
> >
> > - There is one type of syscall on mips32 (scall32-o32) and three types
> > of syscalls on mips64 (scall64-o32, scall64-n32 and scall64-n64). Now
> > convert to C code to handle different types of syscalls.
> >
> > - For some special syscalls (e.g. fork, clone, clone3 and sysmips),
> > save_static_function() wrapper is used to save static registers. Now
> > SAVE_STATIC is used in handle_sys before calling do_syscall(), so the
> > save_static_function() wrapper can be removed.
> >
> > - For sigreturn/rt_sigreturn and sysmips, inline assembly is used to
> > jump to syscall_exit directly for skipping setting the error flag and
> > restoring all registers. Now use regs->regs[27] to mark whether to
> > handle the error flag and always restore all registers in handle_sys,
> > so these functions can return normally as other architecture.
>
> Hmm, that would give us overhead of register context on these syscalls.
>
> I guess it's worthy?
>

Hi, Jiaxun,

Saving and restoring registers against different system calls can be
difficult due to the use of generic entry.
To avoid a lot of duplicate code, I think the overhead is worth it.

> >
> > Signed-off-by: Feiyang Chen <chenfeiyang@loongson.cn>
> > Signed-off-by: Yanteng Si <siyanteng@loongson.cn>
>
> For the code,
>
> Reviewed-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
>
> After spending 3hrs diving into syscall handling hell, I must say you've
> done a good job. I'll start a LTP run to see if we miss any corner
> cases. And left IRQ part for another trial.
>

Thank you for your review. I've already run tests in Unixbench.
It's more reassuring to run tests in LTP, so I'll do that too.

Thanks,
Feiyang

> Thanks.
>
> Jiaxun
>
> > ---
> >   arch/mips/Kconfig                         |   1 +
> >   arch/mips/include/asm/entry-common.h      |  13 ++
> >   arch/mips/include/asm/ptrace.h            |   8 +-
> >   arch/mips/include/asm/sim.h               |  70 -------
> >   arch/mips/include/asm/syscall.h           |   5 +
> >   arch/mips/include/asm/thread_info.h       |  17 +-
> >   arch/mips/include/uapi/asm/ptrace.h       |   7 +-
> >   arch/mips/kernel/Makefile                 |  14 +-
> >   arch/mips/kernel/entry.S                  |  75 ++------
> >   arch/mips/kernel/linux32.c                |   1 -
> >   arch/mips/kernel/ptrace.c                 |  78 --------
> >   arch/mips/kernel/scall.S                  | 135 +++++++++++++
> >   arch/mips/kernel/scall32-o32.S            | 223 ----------------------
> >   arch/mips/kernel/scall64-n32.S            | 107 -----------
> >   arch/mips/kernel/scall64-n64.S            | 116 -----------
> >   arch/mips/kernel/scall64-o32.S            | 221 ---------------------
> >   arch/mips/kernel/signal.c                 |  35 ++--
> >   arch/mips/kernel/signal_n32.c             |  15 +-
> >   arch/mips/kernel/signal_o32.c             |  29 +--
> >   arch/mips/kernel/syscall.c                | 147 +++++++++++---
> >   arch/mips/kernel/syscalls/syscall_n32.tbl |   8 +-
> >   arch/mips/kernel/syscalls/syscall_n64.tbl |   8 +-
> >   arch/mips/kernel/syscalls/syscall_o32.tbl |   8 +-
> >   23 files changed, 346 insertions(+), 995 deletions(-)
> >   create mode 100644 arch/mips/include/asm/entry-common.h
> >   delete mode 100644 arch/mips/include/asm/sim.h
> >   create mode 100644 arch/mips/kernel/scall.S
> >   delete mode 100644 arch/mips/kernel/scall32-o32.S
> >   delete mode 100644 arch/mips/kernel/scall64-n32.S
> >   delete mode 100644 arch/mips/kernel/scall64-n64.S
> >   delete mode 100644 arch/mips/kernel/scall64-o32.S
> >
> > diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
> > index 0cf31a6cbee1..61aa125aa2da 100644
> > --- a/arch/mips/Kconfig
> > +++ b/arch/mips/Kconfig
> > @@ -32,6 +32,7 @@ config MIPS
> >       select GENERIC_ATOMIC64 if !64BIT
> >       select GENERIC_CMOS_UPDATE
> >       select GENERIC_CPU_AUTOPROBE
> > +     select GENERIC_ENTRY
> >       select GENERIC_GETTIMEOFDAY
> >       select GENERIC_IOMAP
> >       select GENERIC_IRQ_PROBE
> > diff --git a/arch/mips/include/asm/entry-common.h b/arch/mips/include/asm/entry-common.h
> > new file mode 100644
> > index 000000000000..0fe2a098ded9
> > --- /dev/null
> > +++ b/arch/mips/include/asm/entry-common.h
> > @@ -0,0 +1,13 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +#ifndef ARCH_LOONGARCH_ENTRY_COMMON_H
> > +#define ARCH_LOONGARCH_ENTRY_COMMON_H
> > +
> > +#include <linux/sched.h>
> > +#include <linux/processor.h>
> > +
> > +static inline bool on_thread_stack(void)
> > +{
> > +     return !(((unsigned long)(current->stack) ^ current_stack_pointer) & ~(THREAD_SIZE - 1));
> > +}
> > +
> > +#endif
> > diff --git a/arch/mips/include/asm/ptrace.h b/arch/mips/include/asm/ptrace.h
> > index daf3cf244ea9..1b8f9d2ddc44 100644
> > --- a/arch/mips/include/asm/ptrace.h
> > +++ b/arch/mips/include/asm/ptrace.h
> > @@ -51,6 +51,11 @@ struct pt_regs {
> >       unsigned long __last[0];
> >   } __aligned(8);
> >
> > +static inline int regs_irqs_disabled(struct pt_regs *regs)
> > +{
> > +     return arch_irqs_disabled_flags(regs->cp0_status);
> > +}
> > +
> >   static inline unsigned long kernel_stack_pointer(struct pt_regs *regs)
> >   {
> >       return regs->regs[29];
> > @@ -156,9 +161,6 @@ static inline long regs_return_value(struct pt_regs *regs)
> >   #define instruction_pointer(regs) ((regs)->cp0_epc)
> >   #define profile_pc(regs) instruction_pointer(regs)
> >
> > -extern asmlinkage long syscall_trace_enter(struct pt_regs *regs, long syscall);
> > -extern asmlinkage void syscall_trace_leave(struct pt_regs *regs);
> > -
> >   extern void die(const char *, struct pt_regs *) __noreturn;
> >
> >   static inline void die_if_kernel(const char *str, struct pt_regs *regs)
> > diff --git a/arch/mips/include/asm/sim.h b/arch/mips/include/asm/sim.h
> > deleted file mode 100644
> > index 59f31a95facd..000000000000
> > --- a/arch/mips/include/asm/sim.h
> > +++ /dev/null
> > @@ -1,70 +0,0 @@
> > -/*
> > - * This file is subject to the terms and conditions of the GNU General Public
> > - * License.  See the file "COPYING" in the main directory of this archive
> > - * for more details.
> > - *
> > - * Copyright (C) 1999, 2000, 2003 Ralf Baechle
> > - * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
> > - */
> > -#ifndef _ASM_SIM_H
> > -#define _ASM_SIM_H
> > -
> > -
> > -#include <asm/asm-offsets.h>
> > -
> > -#define __str2(x) #x
> > -#define __str(x) __str2(x)
> > -
> > -#ifdef CONFIG_32BIT
> > -
> > -#define save_static_function(symbol)                                 \
> > -__asm__(                                                             \
> > -     ".text\n\t"                                                     \
> > -     ".globl\t__" #symbol "\n\t"                                     \
> > -     ".align\t2\n\t"                                                 \
> > -     ".type\t__" #symbol ", @function\n\t"                           \
> > -     ".ent\t__" #symbol ", 0\n__"                                    \
> > -     #symbol":\n\t"                                                  \
> > -     ".frame\t$29, 0, $31\n\t"                                       \
> > -     "sw\t$16,"__str(PT_R16)"($29)\t\t\t# save_static_function\n\t"  \
> > -     "sw\t$17,"__str(PT_R17)"($29)\n\t"                              \
> > -     "sw\t$18,"__str(PT_R18)"($29)\n\t"                              \
> > -     "sw\t$19,"__str(PT_R19)"($29)\n\t"                              \
> > -     "sw\t$20,"__str(PT_R20)"($29)\n\t"                              \
> > -     "sw\t$21,"__str(PT_R21)"($29)\n\t"                              \
> > -     "sw\t$22,"__str(PT_R22)"($29)\n\t"                              \
> > -     "sw\t$23,"__str(PT_R23)"($29)\n\t"                              \
> > -     "sw\t$30,"__str(PT_R30)"($29)\n\t"                              \
> > -     "j\t" #symbol "\n\t"                                            \
> > -     ".end\t__" #symbol "\n\t"                                       \
> > -     ".size\t__" #symbol",. - __" #symbol)
> > -
> > -#endif /* CONFIG_32BIT */
> > -
> > -#ifdef CONFIG_64BIT
> > -
> > -#define save_static_function(symbol)                                 \
> > -__asm__(                                                             \
> > -     ".text\n\t"                                                     \
> > -     ".globl\t__" #symbol "\n\t"                                     \
> > -     ".align\t2\n\t"                                                 \
> > -     ".type\t__" #symbol ", @function\n\t"                           \
> > -     ".ent\t__" #symbol ", 0\n__"                                    \
> > -     #symbol":\n\t"                                                  \
> > -     ".frame\t$29, 0, $31\n\t"                                       \
> > -     "sd\t$16,"__str(PT_R16)"($29)\t\t\t# save_static_function\n\t"  \
> > -     "sd\t$17,"__str(PT_R17)"($29)\n\t"                              \
> > -     "sd\t$18,"__str(PT_R18)"($29)\n\t"                              \
> > -     "sd\t$19,"__str(PT_R19)"($29)\n\t"                              \
> > -     "sd\t$20,"__str(PT_R20)"($29)\n\t"                              \
> > -     "sd\t$21,"__str(PT_R21)"($29)\n\t"                              \
> > -     "sd\t$22,"__str(PT_R22)"($29)\n\t"                              \
> > -     "sd\t$23,"__str(PT_R23)"($29)\n\t"                              \
> > -     "sd\t$30,"__str(PT_R30)"($29)\n\t"                              \
> > -     "j\t" #symbol "\n\t"                                            \
> > -     ".end\t__" #symbol "\n\t"                                       \
> > -     ".size\t__" #symbol",. - __" #symbol)
> > -
> > -#endif /* CONFIG_64BIT */
> > -
> > -#endif /* _ASM_SIM_H */
> > diff --git a/arch/mips/include/asm/syscall.h b/arch/mips/include/asm/syscall.h
> > index 25fa651c937d..02ca0d659428 100644
> > --- a/arch/mips/include/asm/syscall.h
> > +++ b/arch/mips/include/asm/syscall.h
> > @@ -157,4 +157,9 @@ static inline int syscall_get_arch(struct task_struct *task)
> >       return arch;
> >   }
> >
> > +static inline bool arch_syscall_is_vdso_sigreturn(struct pt_regs *regs)
> > +{
> > +     return false;
> > +}
> > +
> >   #endif      /* __ASM_MIPS_SYSCALL_H */
> > diff --git a/arch/mips/include/asm/thread_info.h b/arch/mips/include/asm/thread_info.h
> > index 0b17aaa9e012..5a5237413065 100644
> > --- a/arch/mips/include/asm/thread_info.h
> > +++ b/arch/mips/include/asm/thread_info.h
> > @@ -29,7 +29,8 @@ struct thread_info {
> >       __u32                   cpu;            /* current CPU */
> >       int                     preempt_count;  /* 0 => preemptable, <0 => BUG */
> >       struct pt_regs          *regs;
> > -     long                    syscall;        /* syscall number */
> > +     unsigned long           syscall;        /* syscall number */
> > +     unsigned long           syscall_work;   /* SYSCALL_WORK_ flags */
> >   };
> >
> >   /*
> > @@ -69,6 +70,8 @@ static inline struct thread_info *current_thread_info(void)
> >       return __current_thread_info;
> >   }
> >
> > +register unsigned long current_stack_pointer __asm__("$29");
> > +
> >   #endif /* !__ASSEMBLY__ */
> >
> >   /* thread information allocation */
> > @@ -149,22 +152,10 @@ static inline struct thread_info *current_thread_info(void)
> >   #define _TIF_MSA_CTX_LIVE   (1<<TIF_MSA_CTX_LIVE)
> >   #define _TIF_SYSCALL_TRACEPOINT     (1<<TIF_SYSCALL_TRACEPOINT)
> >
> > -#define _TIF_WORK_SYSCALL_ENTRY      (_TIF_NOHZ | _TIF_SYSCALL_TRACE |       \
> > -                              _TIF_SYSCALL_AUDIT | \
> > -                              _TIF_SYSCALL_TRACEPOINT | _TIF_SECCOMP)
> > -
> > -/* work to do in syscall_trace_leave() */
> > -#define _TIF_WORK_SYSCALL_EXIT       (_TIF_NOHZ | _TIF_SYSCALL_TRACE |       \
> > -                              _TIF_SYSCALL_AUDIT | _TIF_SYSCALL_TRACEPOINT)
> > -
> >   /* work to do on interrupt/exception return */
> >   #define _TIF_WORK_MASK              \
> >       (_TIF_SIGPENDING | _TIF_NEED_RESCHED | _TIF_NOTIFY_RESUME |     \
> >        _TIF_UPROBE | _TIF_NOTIFY_SIGNAL)
> > -/* work to do on any return to u-space */
> > -#define _TIF_ALLWORK_MASK    (_TIF_NOHZ | _TIF_WORK_MASK |           \
> > -                              _TIF_WORK_SYSCALL_EXIT |               \
> > -                              _TIF_SYSCALL_TRACEPOINT)
> >
> >   /*
> >    * We stash processor id into a COP0 register to retrieve it fast
> > diff --git a/arch/mips/include/uapi/asm/ptrace.h b/arch/mips/include/uapi/asm/ptrace.h
> > index f3c025445e45..27e2c85398bc 100644
> > --- a/arch/mips/include/uapi/asm/ptrace.h
> > +++ b/arch/mips/include/uapi/asm/ptrace.h
> > @@ -102,8 +102,9 @@ struct pt_watch_regs {
> >       };
> >   };
> >
> > -#define PTRACE_GET_WATCH_REGS        0xd0
> > -#define PTRACE_SET_WATCH_REGS        0xd1
> > -
> > +#define PTRACE_SYSEMU                        0x1f
> > +#define PTRACE_SYSEMU_SINGLESTEP     0x20
> > +#define PTRACE_GET_WATCH_REGS                0xd0
> > +#define PTRACE_SET_WATCH_REGS                0xd1
> >
> >   #endif /* _UAPI_ASM_PTRACE_H */
> > diff --git a/arch/mips/kernel/Makefile b/arch/mips/kernel/Makefile
> > index 814b3da30501..44875660f6ae 100644
> > --- a/arch/mips/kernel/Makefile
> > +++ b/arch/mips/kernel/Makefile
> > @@ -5,10 +5,10 @@
> >
> >   extra-y             := head.o vmlinux.lds
> >
> > -obj-y                += branch.o cmpxchg.o elf.o entry.o genex.o idle.o irq.o \
> > -                process.o prom.o ptrace.o reset.o setup.o signal.o \
> > -                syscall.o time.o topology.o traps.o unaligned.o watch.o \
> > -                vdso.o cacheinfo.o
> > +obj-y                += branch.o cacheinfo.o cmpxchg.o elf.o entry.o genex.o \
> > +                idle.o irq.o process.o prom.o ptrace.o reset.o scall.o \
> > +                setup.o signal.o syscall.o time.o topology.o traps.o \
> > +                unaligned.o watch.o vdso.o
> >
> >   ifdef CONFIG_CPU_R3K_TLB
> >   obj-y               += cpu-r3k-probe.o
> > @@ -76,11 +76,9 @@ obj-$(CONFIG_IRQ_TXX9)             += irq_txx9.o
> >   obj-$(CONFIG_IRQ_GT641XX)   += irq-gt641xx.o
> >
> >   obj-$(CONFIG_KPROBES)               += kprobes.o
> > -obj-$(CONFIG_32BIT)          += scall32-o32.o
> > -obj-$(CONFIG_64BIT)          += scall64-n64.o
> >   obj-$(CONFIG_MIPS32_COMPAT) += linux32.o ptrace32.o signal32.o
> > -obj-$(CONFIG_MIPS32_N32)     += scall64-n32.o signal_n32.o
> > -obj-$(CONFIG_MIPS32_O32)     += scall64-o32.o signal_o32.o
> > +obj-$(CONFIG_MIPS32_N32)     += signal_n32.o
> > +obj-$(CONFIG_MIPS32_O32)     += signal_o32.o
> >
> >   obj-$(CONFIG_KGDB)          += kgdb.o
> >   obj-$(CONFIG_PROC_FS)               += proc.o
> > diff --git a/arch/mips/kernel/entry.S b/arch/mips/kernel/entry.S
> > index 4b896f5023ff..1a2aec9dab1b 100644
> > --- a/arch/mips/kernel/entry.S
> > +++ b/arch/mips/kernel/entry.S
> > @@ -72,49 +72,32 @@ FEXPORT(ret_from_kernel_thread)
> >       jal     schedule_tail           # a0 = struct task_struct *prev
> >       move    a0, s1
> >       jal     s0
> > -     j       syscall_exit
> > +     move    a0, sp
> > +     jal     syscall_exit_to_user_mode
> > +
> > +     .set    noat
> > +     RESTORE_STATIC
> > +     RESTORE_SOME
> > +     RESTORE_SP_AND_RET
> > +     .set    at
> >
> >   FEXPORT(ret_from_fork)
> >       jal     schedule_tail           # a0 = struct task_struct *prev
> > -
> > -FEXPORT(syscall_exit)
> > -#ifdef CONFIG_DEBUG_RSEQ
> >       move    a0, sp
> > -     jal     rseq_syscall
> > -#endif
> > -     local_irq_disable               # make sure need_resched and
> > -                                     # signals dont change between
> > -                                     # sampling and return
> > -     LONG_L  a2, TI_FLAGS($28)       # current->work
> > -     li      t0, _TIF_ALLWORK_MASK
> > -     and     t0, a2, t0
> > -     bnez    t0, syscall_exit_work
> > +     jal     syscall_exit_to_user_mode
> >
> > -restore_all:                         # restore full frame
> >       .set    noat
> > -     RESTORE_TEMP
> > -     RESTORE_AT
> >       RESTORE_STATIC
> > -restore_partial:             # restore partial frame
> > -#ifdef CONFIG_TRACE_IRQFLAGS
> > -     SAVE_STATIC
> > -     SAVE_AT
> > -     SAVE_TEMP
> > -     LONG_L  v0, PT_STATUS(sp)
> > -#if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
> > -     and     v0, ST0_IEP
> > -#else
> > -     and     v0, ST0_IE
> > -#endif
> > -     beqz    v0, 1f
> > -     jal     trace_hardirqs_on
> > -     b       2f
> > -1:   jal     trace_hardirqs_off
> > -2:
> > +     RESTORE_SOME
> > +     RESTORE_SP_AND_RET
> > +     .set    at
> > +
> > +restore_all:                         # restore full frame
> > +     .set    noat
> >       RESTORE_TEMP
> >       RESTORE_AT
> >       RESTORE_STATIC
> > -#endif
> > +restore_partial:                     # restore partial frame
> >       RESTORE_SOME
> >       RESTORE_SP_AND_RET
> >       .set    at
> > @@ -143,32 +126,6 @@ work_notifysig:                          # deal with pending signals and
> >       jal     do_notify_resume        # a2 already loaded
> >       j       resume_userspace_check
> >
> > -FEXPORT(syscall_exit_partial)
> > -#ifdef CONFIG_DEBUG_RSEQ
> > -     move    a0, sp
> > -     jal     rseq_syscall
> > -#endif
> > -     local_irq_disable               # make sure need_resched doesn't
> > -                                     # change between and return
> > -     LONG_L  a2, TI_FLAGS($28)       # current->work
> > -     li      t0, _TIF_ALLWORK_MASK
> > -     and     t0, a2
> > -     beqz    t0, restore_partial
> > -     SAVE_STATIC
> > -syscall_exit_work:
> > -     LONG_L  t0, PT_STATUS(sp)               # returning to kernel mode?
> > -     andi    t0, t0, KU_USER
> > -     beqz    t0, resume_kernel
> > -     li      t0, _TIF_WORK_SYSCALL_EXIT
> > -     and     t0, a2                  # a2 is preloaded with TI_FLAGS
> > -     beqz    t0, work_pending        # trace bit set?
> > -     local_irq_enable                # could let syscall_trace_leave()
> > -                                     # call schedule() instead
> > -     TRACE_IRQS_ON
> > -     move    a0, sp
> > -     jal     syscall_trace_leave
> > -     b       resume_userspace
> > -
> >   #if defined(CONFIG_CPU_MIPSR2) || defined(CONFIG_CPU_MIPSR5) || \
> >       defined(CONFIG_CPU_MIPSR6) || defined(CONFIG_MIPS_MT)
> >
> > diff --git a/arch/mips/kernel/linux32.c b/arch/mips/kernel/linux32.c
> > index 6b61be486303..2b4b1fc1ff1b 100644
> > --- a/arch/mips/kernel/linux32.c
> > +++ b/arch/mips/kernel/linux32.c
> > @@ -38,7 +38,6 @@
> >   #include <net/scm.h>
> >
> >   #include <asm/compat-signal.h>
> > -#include <asm/sim.h>
> >   #include <linux/uaccess.h>
> >   #include <asm/mmu_context.h>
> >   #include <asm/mman.h>
> > diff --git a/arch/mips/kernel/ptrace.c b/arch/mips/kernel/ptrace.c
> > index db7c5be1d4a3..04c08e41cfd3 100644
> > --- a/arch/mips/kernel/ptrace.c
> > +++ b/arch/mips/kernel/ptrace.c
> > @@ -46,9 +46,6 @@
> >   #include <asm/bootinfo.h>
> >   #include <asm/reg.h>
> >
> > -#define CREATE_TRACE_POINTS
> > -#include <trace/events/syscalls.h>
> > -
> >   /*
> >    * Called by kernel/ptrace.c when detaching..
> >    *
> > @@ -1305,78 +1302,3 @@ long arch_ptrace(struct task_struct *child, long request,
> >    out:
> >       return ret;
> >   }
> > -
> > -/*
> > - * Notification of system call entry/exit
> > - * - triggered by current->work.syscall_trace
> > - */
> > -asmlinkage long syscall_trace_enter(struct pt_regs *regs, long syscall)
> > -{
> > -     user_exit();
> > -
> > -     current_thread_info()->syscall = syscall;
> > -
> > -     if (test_thread_flag(TIF_SYSCALL_TRACE)) {
> > -             if (tracehook_report_syscall_entry(regs))
> > -                     return -1;
> > -             syscall = current_thread_info()->syscall;
> > -     }
> > -
> > -#ifdef CONFIG_SECCOMP
> > -     if (unlikely(test_thread_flag(TIF_SECCOMP))) {
> > -             int ret, i;
> > -             struct seccomp_data sd;
> > -             unsigned long args[6];
> > -
> > -             sd.nr = syscall;
> > -             sd.arch = syscall_get_arch(current);
> > -             syscall_get_arguments(current, regs, args);
> > -             for (i = 0; i < 6; i++)
> > -                     sd.args[i] = args[i];
> > -             sd.instruction_pointer = KSTK_EIP(current);
> > -
> > -             ret = __secure_computing(&sd);
> > -             if (ret == -1)
> > -                     return ret;
> > -             syscall = current_thread_info()->syscall;
> > -     }
> > -#endif
> > -
> > -     if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
> > -             trace_sys_enter(regs, regs->regs[2]);
> > -
> > -     audit_syscall_entry(syscall, regs->regs[4], regs->regs[5],
> > -                         regs->regs[6], regs->regs[7]);
> > -
> > -     /*
> > -      * Negative syscall numbers are mistaken for rejected syscalls, but
> > -      * won't have had the return value set appropriately, so we do so now.
> > -      */
> > -     if (syscall < 0)
> > -             syscall_set_return_value(current, regs, -ENOSYS, 0);
> > -     return syscall;
> > -}
> > -
> > -/*
> > - * Notification of system call entry/exit
> > - * - triggered by current->work.syscall_trace
> > - */
> > -asmlinkage void syscall_trace_leave(struct pt_regs *regs)
> > -{
> > -        /*
> > -      * We may come here right after calling schedule_user()
> > -      * or do_notify_resume(), in which case we can be in RCU
> > -      * user mode.
> > -      */
> > -     user_exit();
> > -
> > -     audit_syscall_exit(regs);
> > -
> > -     if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
> > -             trace_sys_exit(regs, regs_return_value(regs));
> > -
> > -     if (test_thread_flag(TIF_SYSCALL_TRACE))
> > -             tracehook_report_syscall_exit(regs, 0);
> > -
> > -     user_enter();
> > -}
> > diff --git a/arch/mips/kernel/scall.S b/arch/mips/kernel/scall.S
> > new file mode 100644
> > index 000000000000..7b35969151de
> > --- /dev/null
> > +++ b/arch/mips/kernel/scall.S
> > @@ -0,0 +1,135 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +/*
> > + * Copyright (C) 1995, 96, 97, 98, 99, 2000, 01, 02 by Ralf Baechle
> > + * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
> > + * Copyright (C) 2001 MIPS Technologies, Inc.
> > + * Copyright (C) 2004 Thiemo Seufer
> > + * Copyright (C) 2014 Imagination Technologies Ltd.
> > + */
> > +#include <linux/errno.h>
> > +#include <asm/asm.h>
> > +#include <asm/asmmacro.h>
> > +#include <asm/irqflags.h>
> > +#include <asm/mipsregs.h>
> > +#include <asm/regdef.h>
> > +#include <asm/stackframe.h>
> > +#include <asm/asm-offsets.h>
> > +#include <asm/sysmips.h>
> > +#include <asm/thread_info.h>
> > +#include <asm/unistd.h>
> > +#include <asm/war.h>
> > +
> > +     .align  5
> > +NESTED(handle_sys, PT_SIZE, sp)
> > +     .set    noat
> > +     SAVE_SOME
> > +     SAVE_STATIC
> > +     CLI
> > +     .set    at
> > +
> > +     move    a0, sp
> > +     jal     do_syscall
> > +
> > +     .set    noat
> > +     RESTORE_TEMP
> > +     RESTORE_AT
> > +     RESTORE_STATIC
> > +     RESTORE_SOME
> > +     RESTORE_SP_AND_RET
> > +     .set    at
> > +     END(handle_sys)
> > +
> > +#ifdef CONFIG_32BIT
> > +LEAF(sys_syscall)
> > +     subu    t0, a0, __NR_O32_Linux          # check syscall number
> > +     sltiu   v0, t0, __NR_O32_Linux_syscalls
> > +     beqz    t0, einval                      # do not recurse
> > +     sll     t1, t0, 2
> > +     beqz    v0, einval
> > +     lw      t2, sys_call_table(t1)          # syscall routine
> > +
> > +     move    a0, a1                          # shift argument registers
> > +     move    a1, a2
> > +     move    a2, a3
> > +     lw      a3, 16(sp)
> > +     lw      t4, 20(sp)
> > +     lw      t5, 24(sp)
> > +     lw      t6, 28(sp)
> > +     sw      t4, 16(sp)
> > +     sw      t5, 20(sp)
> > +     sw      t6, 24(sp)
> > +     jr      t2
> > +     /* Unreached */
> > +
> > +einval: li   v0, -ENOSYS
> > +     jr      ra
> > +     END(sys_syscall)
> > +
> > +#ifdef CONFIG_MIPS_MT_FPAFF
> > +     /*
> > +      * For FPU affinity scheduling on MIPS MT processors, we need to
> > +      * intercept sys_sched_xxxaffinity() calls until we get a proper hook
> > +      * in kernel/sched/core.c.  Considered only temporary we only support
> > +      * these hooks for the 32-bit kernel - there is no MIPS64 MT processor
> > +      * atm.
> > +      */
> > +#define sys_sched_setaffinity        mipsmt_sys_sched_setaffinity
> > +#define sys_sched_getaffinity        mipsmt_sys_sched_getaffinity
> > +#endif /* CONFIG_MIPS_MT_FPAFF */
> > +
> > +#define __SYSCALL_WITH_COMPAT(nr, native, compat)    __SYSCALL(nr, native)
> > +#define __SYSCALL(nr, entry)         PTR entry
> > +     .align  2
> > +     .type   sys_call_table, @object
> > +EXPORT(sys_call_table)
> > +#include <asm/syscall_table_o32.h>
> > +#endif /* CONFIG_32BIT */
> > +
> > +#ifdef CONFIG_64BIT
> > +#ifdef CONFIG_MIPS32_O32
> > +LEAF(sys32_syscall)
> > +     subu    t0, a0, __NR_O32_Linux          # check syscall number
> > +     sltiu   v0, t0, __NR_O32_Linux_syscalls
> > +     beqz    t0, einval                      # do not recurse
> > +     dsll    t1, t0, 3
> > +     beqz    v0, einval
> > +     ld      t2, sys32_call_table(t1)        # syscall routine
> > +
> > +     move    a0, a1                          # shift argument registers
> > +     move    a1, a2
> > +     move    a2, a3
> > +     move    a3, a4
> > +     move    a4, a5
> > +     move    a5, a6
> > +     move    a6, a7
> > +     jr      t2
> > +     /* Unreached */
> > +
> > +einval: li   v0, -ENOSYS
> > +     jr      ra
> > +     END(sys32_syscall)
> > +
> > +#define __SYSCALL_WITH_COMPAT(nr, native, compat)    __SYSCALL(nr, compat)
> > +#define __SYSCALL(nr, entry) PTR entry
> > +     .align  3
> > +     .type   sys32_call_table,@object
> > +EXPORT(sys32_call_table)
> > +#include <asm/syscall_table_o32.h>
> > +#endif /* CONFIG_MIPS32_O32 */
> > +
> > +#ifdef CONFIG_MIPS32_N32
> > +#undef __SYSCALL
> > +#define __SYSCALL(nr, entry) PTR entry
> > +     .align  3
> > +     .type   sysn32_call_table, @object
> > +EXPORT(sysn32_call_table)
> > +#include <asm/syscall_table_n32.h>
> > +#endif /* CONFIG_MIPS32_N32 */
> > +
> > +#undef __SYSCALL
> > +#define __SYSCALL(nr, entry) PTR entry
> > +     .align  3
> > +     .type   sys_call_table, @object
> > +EXPORT(sys_call_table)
> > +#include <asm/syscall_table_n64.h>
> > +#endif /* CONFIG_64BIT */
> > diff --git a/arch/mips/kernel/scall32-o32.S b/arch/mips/kernel/scall32-o32.S
> > deleted file mode 100644
> > index b1b2e106f711..000000000000
> > --- a/arch/mips/kernel/scall32-o32.S
> > +++ /dev/null
> > @@ -1,223 +0,0 @@
> > -/*
> > - * This file is subject to the terms and conditions of the GNU General Public
> > - * License.  See the file "COPYING" in the main directory of this archive
> > - * for more details.
> > - *
> > - * Copyright (C) 1995-99, 2000- 02, 06 Ralf Baechle <ralf@linux-mips.org>
> > - * Copyright (C) 2001 MIPS Technologies, Inc.
> > - * Copyright (C) 2004 Thiemo Seufer
> > - * Copyright (C) 2014 Imagination Technologies Ltd.
> > - */
> > -#include <linux/errno.h>
> > -#include <asm/asm.h>
> > -#include <asm/asmmacro.h>
> > -#include <asm/irqflags.h>
> > -#include <asm/mipsregs.h>
> > -#include <asm/regdef.h>
> > -#include <asm/stackframe.h>
> > -#include <asm/isadep.h>
> > -#include <asm/sysmips.h>
> > -#include <asm/thread_info.h>
> > -#include <asm/unistd.h>
> > -#include <asm/war.h>
> > -#include <asm/asm-offsets.h>
> > -
> > -     .align  5
> > -NESTED(handle_sys, PT_SIZE, sp)
> > -     .set    noat
> > -     SAVE_SOME
> > -     TRACE_IRQS_ON_RELOAD
> > -     STI
> > -     .set    at
> > -
> > -     lw      t1, PT_EPC(sp)          # skip syscall on return
> > -
> > -     addiu   t1, 4                   # skip to next instruction
> > -     sw      t1, PT_EPC(sp)
> > -
> > -     sw      a3, PT_R26(sp)          # save a3 for syscall restarting
> > -
> > -     /*
> > -      * More than four arguments.  Try to deal with it by copying the
> > -      * stack arguments from the user stack to the kernel stack.
> > -      * This Sucks (TM).
> > -      */
> > -     lw      t0, PT_R29(sp)          # get old user stack pointer
> > -
> > -     /*
> > -      * We intentionally keep the kernel stack a little below the top of
> > -      * userspace so we don't have to do a slower byte accurate check here.
> > -      */
> > -     addu    t4, t0, 32
> > -     bltz    t4, bad_stack           # -> sp is bad
> > -
> > -     /*
> > -      * Ok, copy the args from the luser stack to the kernel stack.
> > -      */
> > -
> > -     .set    push
> > -     .set    noreorder
> > -     .set    nomacro
> > -
> > -load_a4: user_lw(t5, 16(t0))         # argument #5 from usp
> > -load_a5: user_lw(t6, 20(t0))         # argument #6 from usp
> > -load_a6: user_lw(t7, 24(t0))         # argument #7 from usp
> > -load_a7: user_lw(t8, 28(t0))         # argument #8 from usp
> > -loads_done:
> > -
> > -     sw      t5, 16(sp)              # argument #5 to ksp
> > -     sw      t6, 20(sp)              # argument #6 to ksp
> > -     sw      t7, 24(sp)              # argument #7 to ksp
> > -     sw      t8, 28(sp)              # argument #8 to ksp
> > -     .set    pop
> > -
> > -     .section __ex_table,"a"
> > -     PTR     load_a4, bad_stack_a4
> > -     PTR     load_a5, bad_stack_a5
> > -     PTR     load_a6, bad_stack_a6
> > -     PTR     load_a7, bad_stack_a7
> > -     .previous
> > -
> > -     lw      t0, TI_FLAGS($28)       # syscall tracing enabled?
> > -     li      t1, _TIF_WORK_SYSCALL_ENTRY
> > -     and     t0, t1
> > -     bnez    t0, syscall_trace_entry # -> yes
> > -syscall_common:
> > -     subu    v0, v0, __NR_O32_Linux  # check syscall number
> > -     sltiu   t0, v0, __NR_O32_Linux_syscalls
> > -     beqz    t0, illegal_syscall
> > -
> > -     sll     t0, v0, 2
> > -     la      t1, sys_call_table
> > -     addu    t1, t0
> > -     lw      t2, (t1)                # syscall routine
> > -
> > -     beqz    t2, illegal_syscall
> > -
> > -     jalr    t2                      # Do The Real Thing (TM)
> > -
> > -     li      t0, -EMAXERRNO - 1      # error?
> > -     sltu    t0, t0, v0
> > -     sw      t0, PT_R7(sp)           # set error flag
> > -     beqz    t0, 1f
> > -
> > -     lw      t1, PT_R2(sp)           # syscall number
> > -     negu    v0                      # error
> > -     sw      t1, PT_R0(sp)           # save it for syscall restarting
> > -1:   sw      v0, PT_R2(sp)           # result
> > -
> > -o32_syscall_exit:
> > -     j       syscall_exit_partial
> > -
> > -/* ------------------------------------------------------------------------ */
> > -
> > -syscall_trace_entry:
> > -     SAVE_STATIC
> > -     move    a0, sp
> > -
> > -     /*
> > -      * syscall number is in v0 unless we called syscall(__NR_###)
> > -      * where the real syscall number is in a0
> > -      */
> > -     move    a1, v0
> > -     subu    t2, v0,  __NR_O32_Linux
> > -     bnez    t2, 1f /* __NR_syscall at offset 0 */
> > -     lw      a1, PT_R4(sp)
> > -
> > -1:   jal     syscall_trace_enter
> > -
> > -     bltz    v0, 1f                  # seccomp failed? Skip syscall
> > -
> > -     RESTORE_STATIC
> > -     lw      v0, PT_R2(sp)           # Restore syscall (maybe modified)
> > -     lw      a0, PT_R4(sp)           # Restore argument registers
> > -     lw      a1, PT_R5(sp)
> > -     lw      a2, PT_R6(sp)
> > -     lw      a3, PT_R7(sp)
> > -     j       syscall_common
> > -
> > -1:   j       syscall_exit
> > -
> > -/* ------------------------------------------------------------------------ */
> > -
> > -     /*
> > -      * Our open-coded access area sanity test for the stack pointer
> > -      * failed. We probably should handle this case a bit more drastic.
> > -      */
> > -bad_stack:
> > -     li      v0, EFAULT
> > -     sw      v0, PT_R2(sp)
> > -     li      t0, 1                           # set error flag
> > -     sw      t0, PT_R7(sp)
> > -     j       o32_syscall_exit
> > -
> > -bad_stack_a4:
> > -     li      t5, 0
> > -     b       load_a5
> > -
> > -bad_stack_a5:
> > -     li      t6, 0
> > -     b       load_a6
> > -
> > -bad_stack_a6:
> > -     li      t7, 0
> > -     b       load_a7
> > -
> > -bad_stack_a7:
> > -     li      t8, 0
> > -     b       loads_done
> > -
> > -     /*
> > -      * The system call does not exist in this kernel
> > -      */
> > -illegal_syscall:
> > -     li      v0, ENOSYS                      # error
> > -     sw      v0, PT_R2(sp)
> > -     li      t0, 1                           # set error flag
> > -     sw      t0, PT_R7(sp)
> > -     j       o32_syscall_exit
> > -     END(handle_sys)
> > -
> > -     LEAF(sys_syscall)
> > -     subu    t0, a0, __NR_O32_Linux  # check syscall number
> > -     sltiu   v0, t0, __NR_O32_Linux_syscalls
> > -     beqz    t0, einval              # do not recurse
> > -     sll     t1, t0, 2
> > -     beqz    v0, einval
> > -     lw      t2, sys_call_table(t1)          # syscall routine
> > -
> > -     move    a0, a1                          # shift argument registers
> > -     move    a1, a2
> > -     move    a2, a3
> > -     lw      a3, 16(sp)
> > -     lw      t4, 20(sp)
> > -     lw      t5, 24(sp)
> > -     lw      t6, 28(sp)
> > -     sw      t4, 16(sp)
> > -     sw      t5, 20(sp)
> > -     sw      t6, 24(sp)
> > -     jr      t2
> > -     /* Unreached */
> > -
> > -einval: li   v0, -ENOSYS
> > -     jr      ra
> > -     END(sys_syscall)
> > -
> > -#ifdef CONFIG_MIPS_MT_FPAFF
> > -     /*
> > -      * For FPU affinity scheduling on MIPS MT processors, we need to
> > -      * intercept sys_sched_xxxaffinity() calls until we get a proper hook
> > -      * in kernel/sched/core.c.  Considered only temporary we only support
> > -      * these hooks for the 32-bit kernel - there is no MIPS64 MT processor
> > -      * atm.
> > -      */
> > -#define sys_sched_setaffinity        mipsmt_sys_sched_setaffinity
> > -#define sys_sched_getaffinity        mipsmt_sys_sched_getaffinity
> > -#endif /* CONFIG_MIPS_MT_FPAFF */
> > -
> > -#define __SYSCALL_WITH_COMPAT(nr, native, compat)    __SYSCALL(nr, native)
> > -#define __SYSCALL(nr, entry)         PTR entry
> > -     .align  2
> > -     .type   sys_call_table, @object
> > -EXPORT(sys_call_table)
> > -#include <asm/syscall_table_o32.h>
> > diff --git a/arch/mips/kernel/scall64-n32.S b/arch/mips/kernel/scall64-n32.S
> > deleted file mode 100644
> > index f650c55a17dc..000000000000
> > --- a/arch/mips/kernel/scall64-n32.S
> > +++ /dev/null
> > @@ -1,107 +0,0 @@
> > -/*
> > - * This file is subject to the terms and conditions of the GNU General Public
> > - * License.  See the file "COPYING" in the main directory of this archive
> > - * for more details.
> > - *
> > - * Copyright (C) 1995, 96, 97, 98, 99, 2000, 01 by Ralf Baechle
> > - * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
> > - * Copyright (C) 2001 MIPS Technologies, Inc.
> > - */
> > -#include <linux/errno.h>
> > -#include <asm/asm.h>
> > -#include <asm/asmmacro.h>
> > -#include <asm/irqflags.h>
> > -#include <asm/mipsregs.h>
> > -#include <asm/regdef.h>
> > -#include <asm/stackframe.h>
> > -#include <asm/thread_info.h>
> > -#include <asm/unistd.h>
> > -
> > -#ifndef CONFIG_MIPS32_O32
> > -/* No O32, so define handle_sys here */
> > -#define handle_sysn32 handle_sys
> > -#endif
> > -
> > -     .align  5
> > -NESTED(handle_sysn32, PT_SIZE, sp)
> > -#ifndef CONFIG_MIPS32_O32
> > -     .set    noat
> > -     SAVE_SOME
> > -     TRACE_IRQS_ON_RELOAD
> > -     STI
> > -     .set    at
> > -#endif
> > -
> > -     dsubu   t0, v0, __NR_N32_Linux  # check syscall number
> > -     sltiu   t0, t0, __NR_N32_Linux_syscalls
> > -
> > -#ifndef CONFIG_MIPS32_O32
> > -     ld      t1, PT_EPC(sp)          # skip syscall on return
> > -     daddiu  t1, 4                   # skip to next instruction
> > -     sd      t1, PT_EPC(sp)
> > -#endif
> > -     beqz    t0, not_n32_scall
> > -
> > -     sd      a3, PT_R26(sp)          # save a3 for syscall restarting
> > -
> > -     li      t1, _TIF_WORK_SYSCALL_ENTRY
> > -     LONG_L  t0, TI_FLAGS($28)       # syscall tracing enabled?
> > -     and     t0, t1, t0
> > -     bnez    t0, n32_syscall_trace_entry
> > -
> > -syscall_common:
> > -     dsll    t0, v0, 3               # offset into table
> > -     ld      t2, (sysn32_call_table - (__NR_N32_Linux * 8))(t0)
> > -
> > -     jalr    t2                      # Do The Real Thing (TM)
> > -
> > -     li      t0, -EMAXERRNO - 1      # error?
> > -     sltu    t0, t0, v0
> > -     sd      t0, PT_R7(sp)           # set error flag
> > -     beqz    t0, 1f
> > -
> > -     ld      t1, PT_R2(sp)           # syscall number
> > -     dnegu   v0                      # error
> > -     sd      t1, PT_R0(sp)           # save it for syscall restarting
> > -1:   sd      v0, PT_R2(sp)           # result
> > -
> > -     j       syscall_exit_partial
> > -
> > -/* ------------------------------------------------------------------------ */
> > -
> > -n32_syscall_trace_entry:
> > -     SAVE_STATIC
> > -     move    a0, sp
> > -     move    a1, v0
> > -     jal     syscall_trace_enter
> > -
> > -     bltz    v0, 1f                  # seccomp failed? Skip syscall
> > -
> > -     RESTORE_STATIC
> > -     ld      v0, PT_R2(sp)           # Restore syscall (maybe modified)
> > -     ld      a0, PT_R4(sp)           # Restore argument registers
> > -     ld      a1, PT_R5(sp)
> > -     ld      a2, PT_R6(sp)
> > -     ld      a3, PT_R7(sp)
> > -     ld      a4, PT_R8(sp)
> > -     ld      a5, PT_R9(sp)
> > -
> > -     dsubu   t2, v0, __NR_N32_Linux  # check (new) syscall number
> > -     sltiu   t0, t2, __NR_N32_Linux_syscalls
> > -     beqz    t0, not_n32_scall
> > -
> > -     j       syscall_common
> > -
> > -1:   j       syscall_exit
> > -
> > -not_n32_scall:
> > -     /* This is not an n32 compatibility syscall, pass it on to
> > -        the n64 syscall handlers.  */
> > -     j       handle_sys64
> > -
> > -     END(handle_sysn32)
> > -
> > -#define __SYSCALL(nr, entry) PTR entry
> > -     .type   sysn32_call_table, @object
> > -EXPORT(sysn32_call_table)
> > -#include <asm/syscall_table_n32.h>
> > diff --git a/arch/mips/kernel/scall64-n64.S b/arch/mips/kernel/scall64-n64.S
> > deleted file mode 100644
> > index 5d7bfc65e4d0..000000000000
> > --- a/arch/mips/kernel/scall64-n64.S
> > +++ /dev/null
> > @@ -1,116 +0,0 @@
> > -/*
> > - * This file is subject to the terms and conditions of the GNU General Public
> > - * License.  See the file "COPYING" in the main directory of this archive
> > - * for more details.
> > - *
> > - * Copyright (C) 1995, 96, 97, 98, 99, 2000, 01, 02 by Ralf Baechle
> > - * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
> > - * Copyright (C) 2001 MIPS Technologies, Inc.
> > - */
> > -#include <linux/errno.h>
> > -#include <asm/asm.h>
> > -#include <asm/asmmacro.h>
> > -#include <asm/irqflags.h>
> > -#include <asm/mipsregs.h>
> > -#include <asm/regdef.h>
> > -#include <asm/stackframe.h>
> > -#include <asm/asm-offsets.h>
> > -#include <asm/sysmips.h>
> > -#include <asm/thread_info.h>
> > -#include <asm/unistd.h>
> > -#include <asm/war.h>
> > -
> > -#ifndef CONFIG_MIPS32_COMPAT
> > -/* Neither O32 nor N32, so define handle_sys here */
> > -#define handle_sys64 handle_sys
> > -#endif
> > -
> > -     .align  5
> > -NESTED(handle_sys64, PT_SIZE, sp)
> > -#if !defined(CONFIG_MIPS32_O32) && !defined(CONFIG_MIPS32_N32)
> > -     /*
> > -      * When 32-bit compatibility is configured scall_o32.S
> > -      * already did this.
> > -      */
> > -     .set    noat
> > -     SAVE_SOME
> > -     TRACE_IRQS_ON_RELOAD
> > -     STI
> > -     .set    at
> > -#endif
> > -
> > -#if !defined(CONFIG_MIPS32_O32) && !defined(CONFIG_MIPS32_N32)
> > -     ld      t1, PT_EPC(sp)          # skip syscall on return
> > -     daddiu  t1, 4                   # skip to next instruction
> > -     sd      t1, PT_EPC(sp)
> > -#endif
> > -
> > -     sd      a3, PT_R26(sp)          # save a3 for syscall restarting
> > -
> > -     li      t1, _TIF_WORK_SYSCALL_ENTRY
> > -     LONG_L  t0, TI_FLAGS($28)       # syscall tracing enabled?
> > -     and     t0, t1, t0
> > -     bnez    t0, syscall_trace_entry
> > -
> > -syscall_common:
> > -     dsubu   t2, v0, __NR_64_Linux
> > -     sltiu   t0, t2, __NR_64_Linux_syscalls
> > -     beqz    t0, illegal_syscall
> > -
> > -     dsll    t0, t2, 3               # offset into table
> > -     dla     t2, sys_call_table
> > -     daddu   t0, t2, t0
> > -     ld      t2, (t0)                # syscall routine
> > -     beqz    t2, illegal_syscall
> > -
> > -     jalr    t2                      # Do The Real Thing (TM)
> > -
> > -     li      t0, -EMAXERRNO - 1      # error?
> > -     sltu    t0, t0, v0
> > -     sd      t0, PT_R7(sp)           # set error flag
> > -     beqz    t0, 1f
> > -
> > -     ld      t1, PT_R2(sp)           # syscall number
> > -     dnegu   v0                      # error
> > -     sd      t1, PT_R0(sp)           # save it for syscall restarting
> > -1:   sd      v0, PT_R2(sp)           # result
> > -
> > -n64_syscall_exit:
> > -     j       syscall_exit_partial
> > -
> > -/* ------------------------------------------------------------------------ */
> > -
> > -syscall_trace_entry:
> > -     SAVE_STATIC
> > -     move    a0, sp
> > -     move    a1, v0
> > -     jal     syscall_trace_enter
> > -
> > -     bltz    v0, 1f                  # seccomp failed? Skip syscall
> > -
> > -     RESTORE_STATIC
> > -     ld      v0, PT_R2(sp)           # Restore syscall (maybe modified)
> > -     ld      a0, PT_R4(sp)           # Restore argument registers
> > -     ld      a1, PT_R5(sp)
> > -     ld      a2, PT_R6(sp)
> > -     ld      a3, PT_R7(sp)
> > -     ld      a4, PT_R8(sp)
> > -     ld      a5, PT_R9(sp)
> > -     j       syscall_common
> > -
> > -1:   j       syscall_exit
> > -
> > -illegal_syscall:
> > -     /* This also isn't a 64-bit syscall, throw an error.  */
> > -     li      v0, ENOSYS                      # error
> > -     sd      v0, PT_R2(sp)
> > -     li      t0, 1                           # set error flag
> > -     sd      t0, PT_R7(sp)
> > -     j       n64_syscall_exit
> > -     END(handle_sys64)
> > -
> > -#define __SYSCALL(nr, entry) PTR entry
> > -     .align  3
> > -     .type   sys_call_table, @object
> > -EXPORT(sys_call_table)
> > -#include <asm/syscall_table_n64.h>
> > diff --git a/arch/mips/kernel/scall64-o32.S b/arch/mips/kernel/scall64-o32.S
> > deleted file mode 100644
> > index cedc8bd88804..000000000000
> > --- a/arch/mips/kernel/scall64-o32.S
> > +++ /dev/null
> > @@ -1,221 +0,0 @@
> > -/*
> > - * This file is subject to the terms and conditions of the GNU General Public
> > - * License.  See the file "COPYING" in the main directory of this archive
> > - * for more details.
> > - *
> > - * Copyright (C) 1995 - 2000, 2001 by Ralf Baechle
> > - * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
> > - * Copyright (C) 2001 MIPS Technologies, Inc.
> > - * Copyright (C) 2004 Thiemo Seufer
> > - *
> > - * Hairy, the userspace application uses a different argument passing
> > - * convention than the kernel, so we have to translate things from o32
> > - * to ABI64 calling convention.       64-bit syscalls are also processed
> > - * here for now.
> > - */
> > -#include <linux/errno.h>
> > -#include <asm/asm.h>
> > -#include <asm/asmmacro.h>
> > -#include <asm/irqflags.h>
> > -#include <asm/mipsregs.h>
> > -#include <asm/regdef.h>
> > -#include <asm/stackframe.h>
> > -#include <asm/thread_info.h>
> > -#include <asm/unistd.h>
> > -#include <asm/sysmips.h>
> > -
> > -     .align  5
> > -NESTED(handle_sys, PT_SIZE, sp)
> > -     .set    noat
> > -     SAVE_SOME
> > -     TRACE_IRQS_ON_RELOAD
> > -     STI
> > -     .set    at
> > -     ld      t1, PT_EPC(sp)          # skip syscall on return
> > -
> > -     dsubu   t0, v0, __NR_O32_Linux  # check syscall number
> > -     sltiu   t0, t0, __NR_O32_Linux_syscalls
> > -     daddiu  t1, 4                   # skip to next instruction
> > -     sd      t1, PT_EPC(sp)
> > -     beqz    t0, not_o32_scall
> > -#if 0
> > - SAVE_ALL
> > - move a1, v0
> > - ASM_PRINT("Scall %ld\n")
> > - RESTORE_ALL
> > -#endif
> > -
> > -     /* We don't want to stumble over broken sign extensions from
> > -        userland. O32 does never use the upper half. */
> > -     sll     a0, a0, 0
> > -     sll     a1, a1, 0
> > -     sll     a2, a2, 0
> > -     sll     a3, a3, 0
> > -
> > -     sd      a3, PT_R26(sp)          # save a3 for syscall restarting
> > -
> > -     /*
> > -      * More than four arguments.  Try to deal with it by copying the
> > -      * stack arguments from the user stack to the kernel stack.
> > -      * This Sucks (TM).
> > -      *
> > -      * We intentionally keep the kernel stack a little below the top of
> > -      * userspace so we don't have to do a slower byte accurate check here.
> > -      */
> > -     ld      t0, PT_R29(sp)          # get old user stack pointer
> > -     daddu   t1, t0, 32
> > -     bltz    t1, bad_stack
> > -
> > -load_a4: lw  a4, 16(t0)              # argument #5 from usp
> > -load_a5: lw  a5, 20(t0)              # argument #6 from usp
> > -load_a6: lw  a6, 24(t0)              # argument #7 from usp
> > -load_a7: lw  a7, 28(t0)              # argument #8 from usp
> > -loads_done:
> > -
> > -     .section __ex_table,"a"
> > -     PTR     load_a4, bad_stack_a4
> > -     PTR     load_a5, bad_stack_a5
> > -     PTR     load_a6, bad_stack_a6
> > -     PTR     load_a7, bad_stack_a7
> > -     .previous
> > -
> > -     li      t1, _TIF_WORK_SYSCALL_ENTRY
> > -     LONG_L  t0, TI_FLAGS($28)       # syscall tracing enabled?
> > -     and     t0, t1, t0
> > -     bnez    t0, trace_a_syscall
> > -
> > -syscall_common:
> > -     dsll    t0, v0, 3               # offset into table
> > -     ld      t2, (sys32_call_table - (__NR_O32_Linux * 8))(t0)
> > -
> > -     jalr    t2                      # Do The Real Thing (TM)
> > -
> > -     li      t0, -EMAXERRNO - 1      # error?
> > -     sltu    t0, t0, v0
> > -     sd      t0, PT_R7(sp)           # set error flag
> > -     beqz    t0, 1f
> > -
> > -     ld      t1, PT_R2(sp)           # syscall number
> > -     dnegu   v0                      # error
> > -     sd      t1, PT_R0(sp)           # save it for syscall restarting
> > -1:   sd      v0, PT_R2(sp)           # result
> > -
> > -o32_syscall_exit:
> > -     j       syscall_exit_partial
> > -
> > -/* ------------------------------------------------------------------------ */
> > -
> > -trace_a_syscall:
> > -     SAVE_STATIC
> > -     sd      a4, PT_R8(sp)           # Save argument registers
> > -     sd      a5, PT_R9(sp)
> > -     sd      a6, PT_R10(sp)
> > -     sd      a7, PT_R11(sp)          # For indirect syscalls
> > -
> > -     move    a0, sp
> > -     /*
> > -      * absolute syscall number is in v0 unless we called syscall(__NR_###)
> > -      * where the real syscall number is in a0
> > -      * note: NR_syscall is the first O32 syscall but the macro is
> > -      * only defined when compiling with -mabi=32 (CONFIG_32BIT)
> > -      * therefore __NR_O32_Linux is used (4000)
> > -      */
> > -     .set    push
> > -     .set    reorder
> > -     subu    t1, v0,  __NR_O32_Linux
> > -     move    a1, v0
> > -     bnez    t1, 1f /* __NR_syscall at offset 0 */
> > -     ld      a1, PT_R4(sp) /* Arg1 for __NR_syscall case */
> > -     .set    pop
> > -
> > -1:   jal     syscall_trace_enter
> > -
> > -     bltz    v0, 1f                  # seccomp failed? Skip syscall
> > -
> > -     RESTORE_STATIC
> > -     ld      v0, PT_R2(sp)           # Restore syscall (maybe modified)
> > -     ld      a0, PT_R4(sp)           # Restore argument registers
> > -     ld      a1, PT_R5(sp)
> > -     ld      a2, PT_R6(sp)
> > -     ld      a3, PT_R7(sp)
> > -     ld      a4, PT_R8(sp)
> > -     ld      a5, PT_R9(sp)
> > -     ld      a6, PT_R10(sp)
> > -     ld      a7, PT_R11(sp)          # For indirect syscalls
> > -
> > -     dsubu   t0, v0, __NR_O32_Linux  # check (new) syscall number
> > -     sltiu   t0, t0, __NR_O32_Linux_syscalls
> > -     beqz    t0, not_o32_scall
> > -
> > -     j       syscall_common
> > -
> > -1:   j       syscall_exit
> > -
> > -/* ------------------------------------------------------------------------ */
> > -
> > -     /*
> > -      * The stackpointer for a call with more than 4 arguments is bad.
> > -      */
> > -bad_stack:
> > -     li      v0, EFAULT
> > -     sd      v0, PT_R2(sp)
> > -     li      t0, 1                   # set error flag
> > -     sd      t0, PT_R7(sp)
> > -     j       o32_syscall_exit
> > -
> > -bad_stack_a4:
> > -     li      a4, 0
> > -     b       load_a5
> > -
> > -bad_stack_a5:
> > -     li      a5, 0
> > -     b       load_a6
> > -
> > -bad_stack_a6:
> > -     li      a6, 0
> > -     b       load_a7
> > -
> > -bad_stack_a7:
> > -     li      a7, 0
> > -     b       loads_done
> > -
> > -not_o32_scall:
> > -     /*
> > -      * This is not an o32 compatibility syscall, pass it on
> > -      * to the 64-bit syscall handlers.
> > -      */
> > -#ifdef CONFIG_MIPS32_N32
> > -     j       handle_sysn32
> > -#else
> > -     j       handle_sys64
> > -#endif
> > -     END(handle_sys)
> > -
> > -LEAF(sys32_syscall)
> > -     subu    t0, a0, __NR_O32_Linux  # check syscall number
> > -     sltiu   v0, t0, __NR_O32_Linux_syscalls
> > -     beqz    t0, einval              # do not recurse
> > -     dsll    t1, t0, 3
> > -     beqz    v0, einval
> > -     ld      t2, sys32_call_table(t1)                # syscall routine
> > -
> > -     move    a0, a1                  # shift argument registers
> > -     move    a1, a2
> > -     move    a2, a3
> > -     move    a3, a4
> > -     move    a4, a5
> > -     move    a5, a6
> > -     move    a6, a7
> > -     jr      t2
> > -     /* Unreached */
> > -
> > -einval: li   v0, -ENOSYS
> > -     jr      ra
> > -     END(sys32_syscall)
> > -
> > -#define __SYSCALL_WITH_COMPAT(nr, native, compat)    __SYSCALL(nr, compat)
> > -#define __SYSCALL(nr, entry) PTR entry
> > -     .align  3
> > -     .type   sys32_call_table,@object
> > -EXPORT(sys32_call_table)
> > -#include <asm/syscall_table_o32.h>
> > diff --git a/arch/mips/kernel/signal.c b/arch/mips/kernel/signal.c
> > index f1e985109da0..1ec6a0cf1163 100644
> > --- a/arch/mips/kernel/signal.c
> > +++ b/arch/mips/kernel/signal.c
> > @@ -32,7 +32,6 @@
> >   #include <linux/bitops.h>
> >   #include <asm/cacheflush.h>
> >   #include <asm/fpu.h>
> > -#include <asm/sim.h>
> >   #include <asm/ucontext.h>
> >   #include <asm/cpu-features.h>
> >   #include <asm/war.h>
> > @@ -627,7 +626,7 @@ SYSCALL_DEFINE3(sigaction, int, sig, const struct sigaction __user *, act,
> >   #endif
> >
> >   #ifdef CONFIG_TRAD_SIGNALS
> > -asmlinkage void sys_sigreturn(void)
> > +asmlinkage long sys_sigreturn(void)
> >   {
> >       struct sigframe __user *frame;
> >       struct pt_regs *regs;
> > @@ -649,22 +648,16 @@ asmlinkage void sys_sigreturn(void)
> >       else if (sig)
> >               force_sig(sig);
> >
> > -     /*
> > -      * Don't let your children do this ...
> > -      */
> > -     __asm__ __volatile__(
> > -             "move\t$29, %0\n\t"
> > -             "j\tsyscall_exit"
> > -             : /* no outputs */
> > -             : "r" (regs));
> > -     /* Unreached */
> > +     regs->regs[27] = 1;     /* return directly */
> > +     return regs->regs[2];
> >
> >   badframe:
> >       force_sig(SIGSEGV);
> > +     return 0;
> >   }
> >   #endif /* CONFIG_TRAD_SIGNALS */
> >
> > -asmlinkage void sys_rt_sigreturn(void)
> > +asmlinkage long sys_rt_sigreturn(void)
> >   {
> >       struct rt_sigframe __user *frame;
> >       struct pt_regs *regs;
> > @@ -689,18 +682,12 @@ asmlinkage void sys_rt_sigreturn(void)
> >       if (restore_altstack(&frame->rs_uc.uc_stack))
> >               goto badframe;
> >
> > -     /*
> > -      * Don't let your children do this ...
> > -      */
> > -     __asm__ __volatile__(
> > -             "move\t$29, %0\n\t"
> > -             "j\tsyscall_exit"
> > -             : /* no outputs */
> > -             : "r" (regs));
> > -     /* Unreached */
> > +     regs->regs[27] = 1;     /* return directly */
> > +     return regs->regs[2];
> >
> >   badframe:
> >       force_sig(SIGSEGV);
> > +     return 0;
> >   }
> >
> >   #ifdef CONFIG_TRAD_SIGNALS
> > @@ -852,11 +839,11 @@ static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
> >       signal_setup_done(ret, ksig, 0);
> >   }
> >
> > -static void do_signal(struct pt_regs *regs)
> > +void arch_do_signal_or_restart(struct pt_regs *regs, bool has_signal)
> >   {
> >       struct ksignal ksig;
> >
> > -     if (get_signal(&ksig)) {
> > +     if (has_signal && get_signal(&ksig)) {
> >               /* Whee!  Actually deliver the signal.  */
> >               handle_signal(&ksig, regs);
> >               return;
> > @@ -904,7 +891,7 @@ asmlinkage void do_notify_resume(struct pt_regs *regs, void *unused,
> >
> >       /* deal with pending signal delivery */
> >       if (thread_info_flags & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL))
> > -             do_signal(regs);
> > +             arch_do_signal_or_restart(regs, thread_info_flags & _TIF_SIGPENDING);
> >
> >       if (thread_info_flags & _TIF_NOTIFY_RESUME) {
> >               tracehook_notify_resume(regs);
> > diff --git a/arch/mips/kernel/signal_n32.c b/arch/mips/kernel/signal_n32.c
> > index 7bd00fad61af..b52b995a8a9b 100644
> > --- a/arch/mips/kernel/signal_n32.c
> > +++ b/arch/mips/kernel/signal_n32.c
> > @@ -19,7 +19,6 @@
> >   #include <asm/asm.h>
> >   #include <asm/cacheflush.h>
> >   #include <asm/compat-signal.h>
> > -#include <asm/sim.h>
> >   #include <linux/uaccess.h>
> >   #include <asm/ucontext.h>
> >   #include <asm/fpu.h>
> > @@ -51,7 +50,7 @@ struct rt_sigframe_n32 {
> >       struct ucontextn32 rs_uc;
> >   };
> >
> > -asmlinkage void sysn32_rt_sigreturn(void)
> > +asmlinkage long sysn32_rt_sigreturn(void)
> >   {
> >       struct rt_sigframe_n32 __user *frame;
> >       struct pt_regs *regs;
> > @@ -76,18 +75,12 @@ asmlinkage void sysn32_rt_sigreturn(void)
> >       if (compat_restore_altstack(&frame->rs_uc.uc_stack))
> >               goto badframe;
> >
> > -     /*
> > -      * Don't let your children do this ...
> > -      */
> > -     __asm__ __volatile__(
> > -             "move\t$29, %0\n\t"
> > -             "j\tsyscall_exit"
> > -             : /* no outputs */
> > -             : "r" (regs));
> > -     /* Unreached */
> > +     regs->regs[27] = 1;     /* return directly */
> > +     return regs->regs[2];
> >
> >   badframe:
> >       force_sig(SIGSEGV);
> > +     return 0;
> >   }
> >
> >   static int setup_rt_frame_n32(void *sig_return, struct ksignal *ksig,
> > diff --git a/arch/mips/kernel/signal_o32.c b/arch/mips/kernel/signal_o32.c
> > index 299a7a28ca33..9245806e06f1 100644
> > --- a/arch/mips/kernel/signal_o32.c
> > +++ b/arch/mips/kernel/signal_o32.c
> > @@ -17,7 +17,6 @@
> >   #include <asm/abi.h>
> >   #include <asm/compat-signal.h>
> >   #include <asm/dsp.h>
> > -#include <asm/sim.h>
> >   #include <asm/unistd.h>
> >
> >   #include "signal-common.h"
> > @@ -151,7 +150,7 @@ static int setup_frame_32(void *sig_return, struct ksignal *ksig,
> >       return 0;
> >   }
> >
> > -asmlinkage void sys32_rt_sigreturn(void)
> > +asmlinkage long sys32_rt_sigreturn(void)
> >   {
> >       struct rt_sigframe32 __user *frame;
> >       struct pt_regs *regs;
> > @@ -176,18 +175,12 @@ asmlinkage void sys32_rt_sigreturn(void)
> >       if (compat_restore_altstack(&frame->rs_uc.uc_stack))
> >               goto badframe;
> >
> > -     /*
> > -      * Don't let your children do this ...
> > -      */
> > -     __asm__ __volatile__(
> > -             "move\t$29, %0\n\t"
> > -             "j\tsyscall_exit"
> > -             : /* no outputs */
> > -             : "r" (regs));
> > -     /* Unreached */
> > +     regs->regs[27] = 1;     /* return directly */
> > +     return regs->regs[2];
> >
> >   badframe:
> >       force_sig(SIGSEGV);
> > +     return 0;
> >   }
> >
> >   static int setup_rt_frame_32(void *sig_return, struct ksignal *ksig,
> > @@ -253,7 +246,7 @@ struct mips_abi mips_abi_32 = {
> >   };
> >
> >
> > -asmlinkage void sys32_sigreturn(void)
> > +asmlinkage long sys32_sigreturn(void)
> >   {
> >       struct sigframe32 __user *frame;
> >       struct pt_regs *regs;
> > @@ -275,16 +268,10 @@ asmlinkage void sys32_sigreturn(void)
> >       else if (sig)
> >               force_sig(sig);
> >
> > -     /*
> > -      * Don't let your children do this ...
> > -      */
> > -     __asm__ __volatile__(
> > -             "move\t$29, %0\n\t"
> > -             "j\tsyscall_exit"
> > -             : /* no outputs */
> > -             : "r" (regs));
> > -     /* Unreached */
> > +     regs->regs[27] = 1;     /* return directly */
> > +     return regs->regs[2];
> >
> >   badframe:
> >       force_sig(SIGSEGV);
> > +     return 0;
> >   }
> > diff --git a/arch/mips/kernel/syscall.c b/arch/mips/kernel/syscall.c
> > index 2afa3eef486a..6dc78648b274 100644
> > --- a/arch/mips/kernel/syscall.c
> > +++ b/arch/mips/kernel/syscall.c
> > @@ -8,6 +8,7 @@
> >    * Copyright (C) 2001 MIPS Technologies, Inc.
> >    */
> >   #include <linux/capability.h>
> > +#include <linux/entry-common.h>
> >   #include <linux/errno.h>
> >   #include <linux/linkage.h>
> >   #include <linux/fs.h>
> > @@ -35,9 +36,9 @@
> >   #include <asm/cacheflush.h>
> >   #include <asm/asm-offsets.h>
> >   #include <asm/signal.h>
> > -#include <asm/sim.h>
> >   #include <asm/shmparam.h>
> >   #include <asm/sync.h>
> > +#include <asm/syscall.h>
> >   #include <asm/sysmips.h>
> >   #include <asm/switch_to.h>
> >
> > @@ -79,10 +80,6 @@ SYSCALL_DEFINE6(mips_mmap2, unsigned long, addr, unsigned long, len,
> >                              pgoff >> (PAGE_SHIFT - 12));
> >   }
> >
> > -save_static_function(sys_fork);
> > -save_static_function(sys_clone);
> > -save_static_function(sys_clone3);
> > -
> >   SYSCALL_DEFINE1(set_thread_area, unsigned long, addr)
> >   {
> >       struct thread_info *ti = task_thread_info(current);
> > @@ -182,28 +179,11 @@ static inline int mips_atomic_set(unsigned long addr, unsigned long new)
> >               return err;
> >
> >       regs = current_pt_regs();
> > -     regs->regs[2] = old;
> > -     regs->regs[7] = 0;      /* No error */
> > -
> > -     /*
> > -      * Don't let your children do this ...
> > -      */
> > -     __asm__ __volatile__(
> > -     "       move    $29, %0                                         \n"
> > -     "       j       syscall_exit                                    \n"
> > -     : /* no outputs */
> > -     : "r" (regs));
> > -
> > -     /* unreached.  Honestly.  */
> > -     unreachable();
> > +     regs->regs[7] = 0;      /* no error */
> > +     regs->regs[27] = 1;     /* return directly */
> > +     return old;
> >   }
> >
> > -/*
> > - * mips_atomic_set() normally returns directly via syscall_exit potentially
> > - * clobbering static registers, so be sure to preserve them.
> > - */
> > -save_static_function(sys_sysmips);
> > -
> >   SYSCALL_DEFINE3(sysmips, long, cmd, long, arg1, long, arg2)
> >   {
> >       switch (cmd) {
> > @@ -249,3 +229,120 @@ asmlinkage void bad_stack(void)
> >   {
> >       do_exit(SIGSEGV);
> >   }
> > +
> > +#if defined(CONFIG_32BIT) || defined(CONFIG_MIPS32_O32)
> > +static inline int get_args(struct pt_regs *regs)
> > +{
> > +     int *usp = (int *)regs->regs[29];
> > +
> > +#ifdef CONFIG_MIPS32_O32
> > +     /*
> > +      * Hairy, the userspace application uses a different argument passing
> > +      * convention than the kernel, so we have to translate things from o32
> > +      * to ABI64 calling convention.
> > +      *
> > +      * We don't want to stumble over broken sign extensions from userland.
> > +      * O32 does never use the upper half.
> > +      */
> > +     regs->regs[4] = (int)regs->regs[4];
> > +     regs->regs[5] = (int)regs->regs[5];
> > +     regs->regs[6] = (int)regs->regs[6];
> > +     regs->regs[7] = (int)regs->regs[7];
> > +#endif
> > +
> > +     /*
> > +      * More than four arguments.  Try to deal with it by copying the
> > +      * stack arguments from the user stack to the kernel stack.
> > +      * This Sucks (TM).
> > +      *
> > +      * We intentionally keep the kernel stack a little below the top of
> > +      * userspace so we don't have to do a slower byte accurate check here.
> > +      */
> > +     if (!access_ok(usp, 32))
> > +             return -1;
> > +
> > +     get_user(regs->regs[8], usp + 4);
> > +     get_user(regs->regs[9], usp + 5);
> > +     get_user(regs->regs[10], usp + 6);
> > +     get_user(regs->regs[11], usp + 7);
> > +
> > +     return 0;
> > +}
> > +#endif
> > +
> > +typedef long (*sys_call_fn)(unsigned long, unsigned long,
> > +     unsigned long, unsigned long, unsigned long, unsigned long);
> > +
> > +void noinstr do_syscall(struct pt_regs *regs)
> > +{
> > +     unsigned long nr;
> > +     unsigned long ret;
> > +     sys_call_fn syscall_fn = NULL;
> > +
> > +     nr = regs->regs[2];
> > +     current_thread_info()->syscall = nr;
> > +     nr = syscall_enter_from_user_mode(regs, nr);
> > +
> > +     regs->cp0_epc += 4;             /* skip syscall on return */
> > +                                     /* skip to next instruction */
> > +     regs->regs[26] = regs->regs[7]; /* save a3 for syscall restarting */
> > +     regs->regs[27] = 0;             /* do not return directly */
> > +
> > +#ifdef CONFIG_32BIT
> > +     if (nr >= __NR_O32_Linux && nr < __NR_O32_Linux + __NR_O32_Linux_syscalls) {
> > +             if (get_args(regs) < 0) {
> > +                     ret = EFAULT;
> > +                     goto error;
> > +             }
> > +             syscall_fn = (sys_call_fn)sys_call_table[nr - __NR_O32_Linux];
> > +     }
> > +#endif
> > +
> > +#ifdef CONFIG_MIPS32_O32
> > +     if (nr >= __NR_O32_Linux && nr < __NR_O32_Linux + __NR_O32_Linux_syscalls) {
> > +             if (get_args(regs) < 0) {
> > +                     ret = EFAULT;
> > +                     goto error;
> > +             }
> > +             syscall_fn = (sys_call_fn)sys32_call_table[nr - __NR_O32_Linux];
> > +     }
> > +#endif
> > +
> > +#ifdef CONFIG_MIPS32_N32
> > +     if (nr >= __NR_N32_Linux && nr < __NR_N32_Linux + __NR_N32_Linux_syscalls)
> > +             syscall_fn = (sys_call_fn)sysn32_call_table[nr - __NR_N32_Linux];
> > +#endif
> > +
> > +#ifdef CONFIG_64BIT
> > +     if (nr >= __NR_64_Linux && nr < __NR_64_Linux + __NR_64_Linux_syscalls)
> > +             syscall_fn = (sys_call_fn)sys_call_table[nr - __NR_64_Linux];
> > +#endif
> > +
> > +     if (!syscall_fn) {
> > +             ret = ENOSYS;
> > +             goto error;
> > +     }
> > +
> > +     ret = syscall_fn(regs->regs[4], regs->regs[5], regs->regs[6],
> > +                      regs->regs[7], regs->regs[8], regs->regs[9]);
> > +
> > +     if (regs->regs[27])             /* return directly? */
> > +             goto out;
> > +
> > +     regs->regs[7] = 0;              /* clear error flag */
> > +     if (ret >= -EMAXERRNO - 1) {    /* error? */
> > +             regs->regs[0] = nr;     /* save syscall number */
> > +                                     /* for syscall restarting */
> > +             ret = -ret;
> > +             goto error;
> > +     }
> > +
> > +     goto out;
> > +
> > +error:
> > +     regs->regs[7] = 1;              /* set error flag */
> > +
> > +out:
> > +     regs->regs[2] = ret;
> > +     syscall_exit_to_user_mode(regs);
> > +}
> > diff --git a/arch/mips/kernel/syscalls/syscall_n32.tbl b/arch/mips/kernel/syscalls/syscall_n32.tbl
> > index 70e32de2bcaa..d9ae765e51f1 100644
> > --- a/arch/mips/kernel/syscalls/syscall_n32.tbl
> > +++ b/arch/mips/kernel/syscalls/syscall_n32.tbl
> > @@ -62,8 +62,8 @@
> >   52  n32     socketpair                      sys_socketpair
> >   53  n32     setsockopt                      sys_setsockopt
> >   54  n32     getsockopt                      sys_getsockopt
> > -55   n32     clone                           __sys_clone
> > -56   n32     fork                            __sys_fork
> > +55   n32     clone                           sys_clone
> > +56   n32     fork                            sys_fork
> >   57  n32     execve                          compat_sys_execve
> >   58  n32     exit                            sys_exit
> >   59  n32     wait4                           compat_sys_wait4
> > @@ -207,7 +207,7 @@
> >   196 n32     sched_getaffinity               compat_sys_sched_getaffinity
> >   197 n32     cacheflush                      sys_cacheflush
> >   198 n32     cachectl                        sys_cachectl
> > -199  n32     sysmips                         __sys_sysmips
> > +199  n32     sysmips                         sys_sysmips
> >   200 n32     io_setup                        compat_sys_io_setup
> >   201 n32     io_destroy                      sys_io_destroy
> >   202 n32     io_getevents                    sys_io_getevents_time32
> > @@ -373,7 +373,7 @@
> >   432 n32     fsmount                         sys_fsmount
> >   433 n32     fspick                          sys_fspick
> >   434 n32     pidfd_open                      sys_pidfd_open
> > -435  n32     clone3                          __sys_clone3
> > +435  n32     clone3                          sys_clone3
> >   436 n32     close_range                     sys_close_range
> >   437 n32     openat2                         sys_openat2
> >   438 n32     pidfd_getfd                     sys_pidfd_getfd
> > diff --git a/arch/mips/kernel/syscalls/syscall_n64.tbl b/arch/mips/kernel/syscalls/syscall_n64.tbl
> > index 1ca7bc337932..edec3e82d67a 100644
> > --- a/arch/mips/kernel/syscalls/syscall_n64.tbl
> > +++ b/arch/mips/kernel/syscalls/syscall_n64.tbl
> > @@ -62,8 +62,8 @@
> >   52  n64     socketpair                      sys_socketpair
> >   53  n64     setsockopt                      sys_setsockopt
> >   54  n64     getsockopt                      sys_getsockopt
> > -55   n64     clone                           __sys_clone
> > -56   n64     fork                            __sys_fork
> > +55   n64     clone                           sys_clone
> > +56   n64     fork                            sys_fork
> >   57  n64     execve                          sys_execve
> >   58  n64     exit                            sys_exit
> >   59  n64     wait4                           sys_wait4
> > @@ -207,7 +207,7 @@
> >   196 n64     sched_getaffinity               sys_sched_getaffinity
> >   197 n64     cacheflush                      sys_cacheflush
> >   198 n64     cachectl                        sys_cachectl
> > -199  n64     sysmips                         __sys_sysmips
> > +199  n64     sysmips                         sys_sysmips
> >   200 n64     io_setup                        sys_io_setup
> >   201 n64     io_destroy                      sys_io_destroy
> >   202 n64     io_getevents                    sys_io_getevents
> > @@ -349,7 +349,7 @@
> >   432 n64     fsmount                         sys_fsmount
> >   433 n64     fspick                          sys_fspick
> >   434 n64     pidfd_open                      sys_pidfd_open
> > -435  n64     clone3                          __sys_clone3
> > +435  n64     clone3                          sys_clone3
> >   436 n64     close_range                     sys_close_range
> >   437 n64     openat2                         sys_openat2
> >   438 n64     pidfd_getfd                     sys_pidfd_getfd
> > diff --git a/arch/mips/kernel/syscalls/syscall_o32.tbl b/arch/mips/kernel/syscalls/syscall_o32.tbl
> > index a61c35edaa74..89a1f267da6a 100644
> > --- a/arch/mips/kernel/syscalls/syscall_o32.tbl
> > +++ b/arch/mips/kernel/syscalls/syscall_o32.tbl
> > @@ -9,7 +9,7 @@
> >   #
> >   0   o32     syscall                         sys_syscall                     sys32_syscall
> >   1   o32     exit                            sys_exit
> > -2    o32     fork                            __sys_fork
> > +2    o32     fork                            sys_fork
> >   3   o32     read                            sys_read
> >   4   o32     write                           sys_write
> >   5   o32     open                            sys_open                        compat_sys_open
> > @@ -131,7 +131,7 @@
> >   117 o32     ipc                             sys_ipc                         compat_sys_ipc
> >   118 o32     fsync                           sys_fsync
> >   119 o32     sigreturn                       sys_sigreturn                   sys32_sigreturn
> > -120  o32     clone                           __sys_clone
> > +120  o32     clone                           sys_clone
> >   121 o32     setdomainname                   sys_setdomainname
> >   122 o32     uname                           sys_newuname
> >   123 o32     modify_ldt                      sys_ni_syscall
> > @@ -160,7 +160,7 @@
> >   146 o32     writev                          sys_writev
> >   147 o32     cacheflush                      sys_cacheflush
> >   148 o32     cachectl                        sys_cachectl
> > -149  o32     sysmips                         __sys_sysmips
> > +149  o32     sysmips                         sys_sysmips
> >   150 o32     unused150                       sys_ni_syscall
> >   151 o32     getsid                          sys_getsid
> >   152 o32     fdatasync                       sys_fdatasync
> > @@ -422,7 +422,7 @@
> >   432 o32     fsmount                         sys_fsmount
> >   433 o32     fspick                          sys_fspick
> >   434 o32     pidfd_open                      sys_pidfd_open
> > -435  o32     clone3                          __sys_clone3
> > +435  o32     clone3                          sys_clone3
> >   436 o32     close_range                     sys_close_range
> >   437 o32     openat2                         sys_openat2
> >   438 o32     pidfd_getfd                     sys_pidfd_getfd

^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: [PATCH 1/2] mips: convert syscall to generic entry
  2021-09-08  2:08     ` 陈飞扬
@ 2021-09-08  7:15       ` Huacai Chen
  2021-09-08  8:51       ` Thomas Bogendoerfer
  1 sibling, 0 replies; 15+ messages in thread
From: Huacai Chen @ 2021-09-08  7:15 UTC (permalink / raw)
  To: 陈飞扬
  Cc: Jiaxun Yang, Thomas Bogendoerfer, Thomas Gleixner,
	Peter Zijlstra, Andy Lutomirski, Arnd Bergmann, Feiyang Chen,
	open list:MIPS, linux-arch, Yanteng Si

Reviewed-by: Huacai Chen <chenhuacai@kernel.org>

On Wed, Sep 8, 2021 at 10:08 AM 陈飞扬 <chris.chenfeiyang@gmail.com> wrote:
>
> On Tue, 7 Sept 2021 at 21:49, Jiaxun Yang <jiaxun.yang@flygoat.com> wrote:
> >
> >
> > 在 2021/9/7 14:16, FreeFlyingSheep 写道:
> > > From: Feiyang Chen <chenfeiyang@loongson.cn>
> > >
> > > Convert mips syscall to use the generic entry infrastructure from
> > > kernel/entry/*.
> > >
> > > There are a few special things on mips:
> > >
> > > - There is one type of syscall on mips32 (scall32-o32) and three types
> > > of syscalls on mips64 (scall64-o32, scall64-n32 and scall64-n64). Now
> > > convert to C code to handle different types of syscalls.
> > >
> > > - For some special syscalls (e.g. fork, clone, clone3 and sysmips),
> > > save_static_function() wrapper is used to save static registers. Now
> > > SAVE_STATIC is used in handle_sys before calling do_syscall(), so the
> > > save_static_function() wrapper can be removed.
> > >
> > > - For sigreturn/rt_sigreturn and sysmips, inline assembly is used to
> > > jump to syscall_exit directly for skipping setting the error flag and
> > > restoring all registers. Now use regs->regs[27] to mark whether to
> > > handle the error flag and always restore all registers in handle_sys,
> > > so these functions can return normally as other architecture.
> >
> > Hmm, that would give us overhead of register context on these syscalls.
> >
> > I guess it's worthy?
> >
>
> Hi, Jiaxun,
>
> Saving and restoring registers against different system calls can be
> difficult due to the use of generic entry.
> To avoid a lot of duplicate code, I think the overhead is worth it.
>
> > >
> > > Signed-off-by: Feiyang Chen <chenfeiyang@loongson.cn>
> > > Signed-off-by: Yanteng Si <siyanteng@loongson.cn>
> >
> > For the code,
> >
> > Reviewed-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
> >
> > After spending 3hrs diving into syscall handling hell, I must say you've
> > done a good job. I'll start a LTP run to see if we miss any corner
> > cases. And left IRQ part for another trial.
> >
>
> Thank you for your review. I've already run tests in Unixbench.
> It's more reassuring to run tests in LTP, so I'll do that too.
>
> Thanks,
> Feiyang
>
> > Thanks.
> >
> > Jiaxun
> >
> > > ---
> > >   arch/mips/Kconfig                         |   1 +
> > >   arch/mips/include/asm/entry-common.h      |  13 ++
> > >   arch/mips/include/asm/ptrace.h            |   8 +-
> > >   arch/mips/include/asm/sim.h               |  70 -------
> > >   arch/mips/include/asm/syscall.h           |   5 +
> > >   arch/mips/include/asm/thread_info.h       |  17 +-
> > >   arch/mips/include/uapi/asm/ptrace.h       |   7 +-
> > >   arch/mips/kernel/Makefile                 |  14 +-
> > >   arch/mips/kernel/entry.S                  |  75 ++------
> > >   arch/mips/kernel/linux32.c                |   1 -
> > >   arch/mips/kernel/ptrace.c                 |  78 --------
> > >   arch/mips/kernel/scall.S                  | 135 +++++++++++++
> > >   arch/mips/kernel/scall32-o32.S            | 223 ----------------------
> > >   arch/mips/kernel/scall64-n32.S            | 107 -----------
> > >   arch/mips/kernel/scall64-n64.S            | 116 -----------
> > >   arch/mips/kernel/scall64-o32.S            | 221 ---------------------
> > >   arch/mips/kernel/signal.c                 |  35 ++--
> > >   arch/mips/kernel/signal_n32.c             |  15 +-
> > >   arch/mips/kernel/signal_o32.c             |  29 +--
> > >   arch/mips/kernel/syscall.c                | 147 +++++++++++---
> > >   arch/mips/kernel/syscalls/syscall_n32.tbl |   8 +-
> > >   arch/mips/kernel/syscalls/syscall_n64.tbl |   8 +-
> > >   arch/mips/kernel/syscalls/syscall_o32.tbl |   8 +-
> > >   23 files changed, 346 insertions(+), 995 deletions(-)
> > >   create mode 100644 arch/mips/include/asm/entry-common.h
> > >   delete mode 100644 arch/mips/include/asm/sim.h
> > >   create mode 100644 arch/mips/kernel/scall.S
> > >   delete mode 100644 arch/mips/kernel/scall32-o32.S
> > >   delete mode 100644 arch/mips/kernel/scall64-n32.S
> > >   delete mode 100644 arch/mips/kernel/scall64-n64.S
> > >   delete mode 100644 arch/mips/kernel/scall64-o32.S
> > >
> > > diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
> > > index 0cf31a6cbee1..61aa125aa2da 100644
> > > --- a/arch/mips/Kconfig
> > > +++ b/arch/mips/Kconfig
> > > @@ -32,6 +32,7 @@ config MIPS
> > >       select GENERIC_ATOMIC64 if !64BIT
> > >       select GENERIC_CMOS_UPDATE
> > >       select GENERIC_CPU_AUTOPROBE
> > > +     select GENERIC_ENTRY
> > >       select GENERIC_GETTIMEOFDAY
> > >       select GENERIC_IOMAP
> > >       select GENERIC_IRQ_PROBE
> > > diff --git a/arch/mips/include/asm/entry-common.h b/arch/mips/include/asm/entry-common.h
> > > new file mode 100644
> > > index 000000000000..0fe2a098ded9
> > > --- /dev/null
> > > +++ b/arch/mips/include/asm/entry-common.h
> > > @@ -0,0 +1,13 @@
> > > +/* SPDX-License-Identifier: GPL-2.0 */
> > > +#ifndef ARCH_LOONGARCH_ENTRY_COMMON_H
> > > +#define ARCH_LOONGARCH_ENTRY_COMMON_H
> > > +
> > > +#include <linux/sched.h>
> > > +#include <linux/processor.h>
> > > +
> > > +static inline bool on_thread_stack(void)
> > > +{
> > > +     return !(((unsigned long)(current->stack) ^ current_stack_pointer) & ~(THREAD_SIZE - 1));
> > > +}
> > > +
> > > +#endif
> > > diff --git a/arch/mips/include/asm/ptrace.h b/arch/mips/include/asm/ptrace.h
> > > index daf3cf244ea9..1b8f9d2ddc44 100644
> > > --- a/arch/mips/include/asm/ptrace.h
> > > +++ b/arch/mips/include/asm/ptrace.h
> > > @@ -51,6 +51,11 @@ struct pt_regs {
> > >       unsigned long __last[0];
> > >   } __aligned(8);
> > >
> > > +static inline int regs_irqs_disabled(struct pt_regs *regs)
> > > +{
> > > +     return arch_irqs_disabled_flags(regs->cp0_status);
> > > +}
> > > +
> > >   static inline unsigned long kernel_stack_pointer(struct pt_regs *regs)
> > >   {
> > >       return regs->regs[29];
> > > @@ -156,9 +161,6 @@ static inline long regs_return_value(struct pt_regs *regs)
> > >   #define instruction_pointer(regs) ((regs)->cp0_epc)
> > >   #define profile_pc(regs) instruction_pointer(regs)
> > >
> > > -extern asmlinkage long syscall_trace_enter(struct pt_regs *regs, long syscall);
> > > -extern asmlinkage void syscall_trace_leave(struct pt_regs *regs);
> > > -
> > >   extern void die(const char *, struct pt_regs *) __noreturn;
> > >
> > >   static inline void die_if_kernel(const char *str, struct pt_regs *regs)
> > > diff --git a/arch/mips/include/asm/sim.h b/arch/mips/include/asm/sim.h
> > > deleted file mode 100644
> > > index 59f31a95facd..000000000000
> > > --- a/arch/mips/include/asm/sim.h
> > > +++ /dev/null
> > > @@ -1,70 +0,0 @@
> > > -/*
> > > - * This file is subject to the terms and conditions of the GNU General Public
> > > - * License.  See the file "COPYING" in the main directory of this archive
> > > - * for more details.
> > > - *
> > > - * Copyright (C) 1999, 2000, 2003 Ralf Baechle
> > > - * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
> > > - */
> > > -#ifndef _ASM_SIM_H
> > > -#define _ASM_SIM_H
> > > -
> > > -
> > > -#include <asm/asm-offsets.h>
> > > -
> > > -#define __str2(x) #x
> > > -#define __str(x) __str2(x)
> > > -
> > > -#ifdef CONFIG_32BIT
> > > -
> > > -#define save_static_function(symbol)                                 \
> > > -__asm__(                                                             \
> > > -     ".text\n\t"                                                     \
> > > -     ".globl\t__" #symbol "\n\t"                                     \
> > > -     ".align\t2\n\t"                                                 \
> > > -     ".type\t__" #symbol ", @function\n\t"                           \
> > > -     ".ent\t__" #symbol ", 0\n__"                                    \
> > > -     #symbol":\n\t"                                                  \
> > > -     ".frame\t$29, 0, $31\n\t"                                       \
> > > -     "sw\t$16,"__str(PT_R16)"($29)\t\t\t# save_static_function\n\t"  \
> > > -     "sw\t$17,"__str(PT_R17)"($29)\n\t"                              \
> > > -     "sw\t$18,"__str(PT_R18)"($29)\n\t"                              \
> > > -     "sw\t$19,"__str(PT_R19)"($29)\n\t"                              \
> > > -     "sw\t$20,"__str(PT_R20)"($29)\n\t"                              \
> > > -     "sw\t$21,"__str(PT_R21)"($29)\n\t"                              \
> > > -     "sw\t$22,"__str(PT_R22)"($29)\n\t"                              \
> > > -     "sw\t$23,"__str(PT_R23)"($29)\n\t"                              \
> > > -     "sw\t$30,"__str(PT_R30)"($29)\n\t"                              \
> > > -     "j\t" #symbol "\n\t"                                            \
> > > -     ".end\t__" #symbol "\n\t"                                       \
> > > -     ".size\t__" #symbol",. - __" #symbol)
> > > -
> > > -#endif /* CONFIG_32BIT */
> > > -
> > > -#ifdef CONFIG_64BIT
> > > -
> > > -#define save_static_function(symbol)                                 \
> > > -__asm__(                                                             \
> > > -     ".text\n\t"                                                     \
> > > -     ".globl\t__" #symbol "\n\t"                                     \
> > > -     ".align\t2\n\t"                                                 \
> > > -     ".type\t__" #symbol ", @function\n\t"                           \
> > > -     ".ent\t__" #symbol ", 0\n__"                                    \
> > > -     #symbol":\n\t"                                                  \
> > > -     ".frame\t$29, 0, $31\n\t"                                       \
> > > -     "sd\t$16,"__str(PT_R16)"($29)\t\t\t# save_static_function\n\t"  \
> > > -     "sd\t$17,"__str(PT_R17)"($29)\n\t"                              \
> > > -     "sd\t$18,"__str(PT_R18)"($29)\n\t"                              \
> > > -     "sd\t$19,"__str(PT_R19)"($29)\n\t"                              \
> > > -     "sd\t$20,"__str(PT_R20)"($29)\n\t"                              \
> > > -     "sd\t$21,"__str(PT_R21)"($29)\n\t"                              \
> > > -     "sd\t$22,"__str(PT_R22)"($29)\n\t"                              \
> > > -     "sd\t$23,"__str(PT_R23)"($29)\n\t"                              \
> > > -     "sd\t$30,"__str(PT_R30)"($29)\n\t"                              \
> > > -     "j\t" #symbol "\n\t"                                            \
> > > -     ".end\t__" #symbol "\n\t"                                       \
> > > -     ".size\t__" #symbol",. - __" #symbol)
> > > -
> > > -#endif /* CONFIG_64BIT */
> > > -
> > > -#endif /* _ASM_SIM_H */
> > > diff --git a/arch/mips/include/asm/syscall.h b/arch/mips/include/asm/syscall.h
> > > index 25fa651c937d..02ca0d659428 100644
> > > --- a/arch/mips/include/asm/syscall.h
> > > +++ b/arch/mips/include/asm/syscall.h
> > > @@ -157,4 +157,9 @@ static inline int syscall_get_arch(struct task_struct *task)
> > >       return arch;
> > >   }
> > >
> > > +static inline bool arch_syscall_is_vdso_sigreturn(struct pt_regs *regs)
> > > +{
> > > +     return false;
> > > +}
> > > +
> > >   #endif      /* __ASM_MIPS_SYSCALL_H */
> > > diff --git a/arch/mips/include/asm/thread_info.h b/arch/mips/include/asm/thread_info.h
> > > index 0b17aaa9e012..5a5237413065 100644
> > > --- a/arch/mips/include/asm/thread_info.h
> > > +++ b/arch/mips/include/asm/thread_info.h
> > > @@ -29,7 +29,8 @@ struct thread_info {
> > >       __u32                   cpu;            /* current CPU */
> > >       int                     preempt_count;  /* 0 => preemptable, <0 => BUG */
> > >       struct pt_regs          *regs;
> > > -     long                    syscall;        /* syscall number */
> > > +     unsigned long           syscall;        /* syscall number */
> > > +     unsigned long           syscall_work;   /* SYSCALL_WORK_ flags */
> > >   };
> > >
> > >   /*
> > > @@ -69,6 +70,8 @@ static inline struct thread_info *current_thread_info(void)
> > >       return __current_thread_info;
> > >   }
> > >
> > > +register unsigned long current_stack_pointer __asm__("$29");
> > > +
> > >   #endif /* !__ASSEMBLY__ */
> > >
> > >   /* thread information allocation */
> > > @@ -149,22 +152,10 @@ static inline struct thread_info *current_thread_info(void)
> > >   #define _TIF_MSA_CTX_LIVE   (1<<TIF_MSA_CTX_LIVE)
> > >   #define _TIF_SYSCALL_TRACEPOINT     (1<<TIF_SYSCALL_TRACEPOINT)
> > >
> > > -#define _TIF_WORK_SYSCALL_ENTRY      (_TIF_NOHZ | _TIF_SYSCALL_TRACE |       \
> > > -                              _TIF_SYSCALL_AUDIT | \
> > > -                              _TIF_SYSCALL_TRACEPOINT | _TIF_SECCOMP)
> > > -
> > > -/* work to do in syscall_trace_leave() */
> > > -#define _TIF_WORK_SYSCALL_EXIT       (_TIF_NOHZ | _TIF_SYSCALL_TRACE |       \
> > > -                              _TIF_SYSCALL_AUDIT | _TIF_SYSCALL_TRACEPOINT)
> > > -
> > >   /* work to do on interrupt/exception return */
> > >   #define _TIF_WORK_MASK              \
> > >       (_TIF_SIGPENDING | _TIF_NEED_RESCHED | _TIF_NOTIFY_RESUME |     \
> > >        _TIF_UPROBE | _TIF_NOTIFY_SIGNAL)
> > > -/* work to do on any return to u-space */
> > > -#define _TIF_ALLWORK_MASK    (_TIF_NOHZ | _TIF_WORK_MASK |           \
> > > -                              _TIF_WORK_SYSCALL_EXIT |               \
> > > -                              _TIF_SYSCALL_TRACEPOINT)
> > >
> > >   /*
> > >    * We stash processor id into a COP0 register to retrieve it fast
> > > diff --git a/arch/mips/include/uapi/asm/ptrace.h b/arch/mips/include/uapi/asm/ptrace.h
> > > index f3c025445e45..27e2c85398bc 100644
> > > --- a/arch/mips/include/uapi/asm/ptrace.h
> > > +++ b/arch/mips/include/uapi/asm/ptrace.h
> > > @@ -102,8 +102,9 @@ struct pt_watch_regs {
> > >       };
> > >   };
> > >
> > > -#define PTRACE_GET_WATCH_REGS        0xd0
> > > -#define PTRACE_SET_WATCH_REGS        0xd1
> > > -
> > > +#define PTRACE_SYSEMU                        0x1f
> > > +#define PTRACE_SYSEMU_SINGLESTEP     0x20
> > > +#define PTRACE_GET_WATCH_REGS                0xd0
> > > +#define PTRACE_SET_WATCH_REGS                0xd1
> > >
> > >   #endif /* _UAPI_ASM_PTRACE_H */
> > > diff --git a/arch/mips/kernel/Makefile b/arch/mips/kernel/Makefile
> > > index 814b3da30501..44875660f6ae 100644
> > > --- a/arch/mips/kernel/Makefile
> > > +++ b/arch/mips/kernel/Makefile
> > > @@ -5,10 +5,10 @@
> > >
> > >   extra-y             := head.o vmlinux.lds
> > >
> > > -obj-y                += branch.o cmpxchg.o elf.o entry.o genex.o idle.o irq.o \
> > > -                process.o prom.o ptrace.o reset.o setup.o signal.o \
> > > -                syscall.o time.o topology.o traps.o unaligned.o watch.o \
> > > -                vdso.o cacheinfo.o
> > > +obj-y                += branch.o cacheinfo.o cmpxchg.o elf.o entry.o genex.o \
> > > +                idle.o irq.o process.o prom.o ptrace.o reset.o scall.o \
> > > +                setup.o signal.o syscall.o time.o topology.o traps.o \
> > > +                unaligned.o watch.o vdso.o
> > >
> > >   ifdef CONFIG_CPU_R3K_TLB
> > >   obj-y               += cpu-r3k-probe.o
> > > @@ -76,11 +76,9 @@ obj-$(CONFIG_IRQ_TXX9)             += irq_txx9.o
> > >   obj-$(CONFIG_IRQ_GT641XX)   += irq-gt641xx.o
> > >
> > >   obj-$(CONFIG_KPROBES)               += kprobes.o
> > > -obj-$(CONFIG_32BIT)          += scall32-o32.o
> > > -obj-$(CONFIG_64BIT)          += scall64-n64.o
> > >   obj-$(CONFIG_MIPS32_COMPAT) += linux32.o ptrace32.o signal32.o
> > > -obj-$(CONFIG_MIPS32_N32)     += scall64-n32.o signal_n32.o
> > > -obj-$(CONFIG_MIPS32_O32)     += scall64-o32.o signal_o32.o
> > > +obj-$(CONFIG_MIPS32_N32)     += signal_n32.o
> > > +obj-$(CONFIG_MIPS32_O32)     += signal_o32.o
> > >
> > >   obj-$(CONFIG_KGDB)          += kgdb.o
> > >   obj-$(CONFIG_PROC_FS)               += proc.o
> > > diff --git a/arch/mips/kernel/entry.S b/arch/mips/kernel/entry.S
> > > index 4b896f5023ff..1a2aec9dab1b 100644
> > > --- a/arch/mips/kernel/entry.S
> > > +++ b/arch/mips/kernel/entry.S
> > > @@ -72,49 +72,32 @@ FEXPORT(ret_from_kernel_thread)
> > >       jal     schedule_tail           # a0 = struct task_struct *prev
> > >       move    a0, s1
> > >       jal     s0
> > > -     j       syscall_exit
> > > +     move    a0, sp
> > > +     jal     syscall_exit_to_user_mode
> > > +
> > > +     .set    noat
> > > +     RESTORE_STATIC
> > > +     RESTORE_SOME
> > > +     RESTORE_SP_AND_RET
> > > +     .set    at
> > >
> > >   FEXPORT(ret_from_fork)
> > >       jal     schedule_tail           # a0 = struct task_struct *prev
> > > -
> > > -FEXPORT(syscall_exit)
> > > -#ifdef CONFIG_DEBUG_RSEQ
> > >       move    a0, sp
> > > -     jal     rseq_syscall
> > > -#endif
> > > -     local_irq_disable               # make sure need_resched and
> > > -                                     # signals dont change between
> > > -                                     # sampling and return
> > > -     LONG_L  a2, TI_FLAGS($28)       # current->work
> > > -     li      t0, _TIF_ALLWORK_MASK
> > > -     and     t0, a2, t0
> > > -     bnez    t0, syscall_exit_work
> > > +     jal     syscall_exit_to_user_mode
> > >
> > > -restore_all:                         # restore full frame
> > >       .set    noat
> > > -     RESTORE_TEMP
> > > -     RESTORE_AT
> > >       RESTORE_STATIC
> > > -restore_partial:             # restore partial frame
> > > -#ifdef CONFIG_TRACE_IRQFLAGS
> > > -     SAVE_STATIC
> > > -     SAVE_AT
> > > -     SAVE_TEMP
> > > -     LONG_L  v0, PT_STATUS(sp)
> > > -#if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
> > > -     and     v0, ST0_IEP
> > > -#else
> > > -     and     v0, ST0_IE
> > > -#endif
> > > -     beqz    v0, 1f
> > > -     jal     trace_hardirqs_on
> > > -     b       2f
> > > -1:   jal     trace_hardirqs_off
> > > -2:
> > > +     RESTORE_SOME
> > > +     RESTORE_SP_AND_RET
> > > +     .set    at
> > > +
> > > +restore_all:                         # restore full frame
> > > +     .set    noat
> > >       RESTORE_TEMP
> > >       RESTORE_AT
> > >       RESTORE_STATIC
> > > -#endif
> > > +restore_partial:                     # restore partial frame
> > >       RESTORE_SOME
> > >       RESTORE_SP_AND_RET
> > >       .set    at
> > > @@ -143,32 +126,6 @@ work_notifysig:                          # deal with pending signals and
> > >       jal     do_notify_resume        # a2 already loaded
> > >       j       resume_userspace_check
> > >
> > > -FEXPORT(syscall_exit_partial)
> > > -#ifdef CONFIG_DEBUG_RSEQ
> > > -     move    a0, sp
> > > -     jal     rseq_syscall
> > > -#endif
> > > -     local_irq_disable               # make sure need_resched doesn't
> > > -                                     # change between and return
> > > -     LONG_L  a2, TI_FLAGS($28)       # current->work
> > > -     li      t0, _TIF_ALLWORK_MASK
> > > -     and     t0, a2
> > > -     beqz    t0, restore_partial
> > > -     SAVE_STATIC
> > > -syscall_exit_work:
> > > -     LONG_L  t0, PT_STATUS(sp)               # returning to kernel mode?
> > > -     andi    t0, t0, KU_USER
> > > -     beqz    t0, resume_kernel
> > > -     li      t0, _TIF_WORK_SYSCALL_EXIT
> > > -     and     t0, a2                  # a2 is preloaded with TI_FLAGS
> > > -     beqz    t0, work_pending        # trace bit set?
> > > -     local_irq_enable                # could let syscall_trace_leave()
> > > -                                     # call schedule() instead
> > > -     TRACE_IRQS_ON
> > > -     move    a0, sp
> > > -     jal     syscall_trace_leave
> > > -     b       resume_userspace
> > > -
> > >   #if defined(CONFIG_CPU_MIPSR2) || defined(CONFIG_CPU_MIPSR5) || \
> > >       defined(CONFIG_CPU_MIPSR6) || defined(CONFIG_MIPS_MT)
> > >
> > > diff --git a/arch/mips/kernel/linux32.c b/arch/mips/kernel/linux32.c
> > > index 6b61be486303..2b4b1fc1ff1b 100644
> > > --- a/arch/mips/kernel/linux32.c
> > > +++ b/arch/mips/kernel/linux32.c
> > > @@ -38,7 +38,6 @@
> > >   #include <net/scm.h>
> > >
> > >   #include <asm/compat-signal.h>
> > > -#include <asm/sim.h>
> > >   #include <linux/uaccess.h>
> > >   #include <asm/mmu_context.h>
> > >   #include <asm/mman.h>
> > > diff --git a/arch/mips/kernel/ptrace.c b/arch/mips/kernel/ptrace.c
> > > index db7c5be1d4a3..04c08e41cfd3 100644
> > > --- a/arch/mips/kernel/ptrace.c
> > > +++ b/arch/mips/kernel/ptrace.c
> > > @@ -46,9 +46,6 @@
> > >   #include <asm/bootinfo.h>
> > >   #include <asm/reg.h>
> > >
> > > -#define CREATE_TRACE_POINTS
> > > -#include <trace/events/syscalls.h>
> > > -
> > >   /*
> > >    * Called by kernel/ptrace.c when detaching..
> > >    *
> > > @@ -1305,78 +1302,3 @@ long arch_ptrace(struct task_struct *child, long request,
> > >    out:
> > >       return ret;
> > >   }
> > > -
> > > -/*
> > > - * Notification of system call entry/exit
> > > - * - triggered by current->work.syscall_trace
> > > - */
> > > -asmlinkage long syscall_trace_enter(struct pt_regs *regs, long syscall)
> > > -{
> > > -     user_exit();
> > > -
> > > -     current_thread_info()->syscall = syscall;
> > > -
> > > -     if (test_thread_flag(TIF_SYSCALL_TRACE)) {
> > > -             if (tracehook_report_syscall_entry(regs))
> > > -                     return -1;
> > > -             syscall = current_thread_info()->syscall;
> > > -     }
> > > -
> > > -#ifdef CONFIG_SECCOMP
> > > -     if (unlikely(test_thread_flag(TIF_SECCOMP))) {
> > > -             int ret, i;
> > > -             struct seccomp_data sd;
> > > -             unsigned long args[6];
> > > -
> > > -             sd.nr = syscall;
> > > -             sd.arch = syscall_get_arch(current);
> > > -             syscall_get_arguments(current, regs, args);
> > > -             for (i = 0; i < 6; i++)
> > > -                     sd.args[i] = args[i];
> > > -             sd.instruction_pointer = KSTK_EIP(current);
> > > -
> > > -             ret = __secure_computing(&sd);
> > > -             if (ret == -1)
> > > -                     return ret;
> > > -             syscall = current_thread_info()->syscall;
> > > -     }
> > > -#endif
> > > -
> > > -     if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
> > > -             trace_sys_enter(regs, regs->regs[2]);
> > > -
> > > -     audit_syscall_entry(syscall, regs->regs[4], regs->regs[5],
> > > -                         regs->regs[6], regs->regs[7]);
> > > -
> > > -     /*
> > > -      * Negative syscall numbers are mistaken for rejected syscalls, but
> > > -      * won't have had the return value set appropriately, so we do so now.
> > > -      */
> > > -     if (syscall < 0)
> > > -             syscall_set_return_value(current, regs, -ENOSYS, 0);
> > > -     return syscall;
> > > -}
> > > -
> > > -/*
> > > - * Notification of system call entry/exit
> > > - * - triggered by current->work.syscall_trace
> > > - */
> > > -asmlinkage void syscall_trace_leave(struct pt_regs *regs)
> > > -{
> > > -        /*
> > > -      * We may come here right after calling schedule_user()
> > > -      * or do_notify_resume(), in which case we can be in RCU
> > > -      * user mode.
> > > -      */
> > > -     user_exit();
> > > -
> > > -     audit_syscall_exit(regs);
> > > -
> > > -     if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
> > > -             trace_sys_exit(regs, regs_return_value(regs));
> > > -
> > > -     if (test_thread_flag(TIF_SYSCALL_TRACE))
> > > -             tracehook_report_syscall_exit(regs, 0);
> > > -
> > > -     user_enter();
> > > -}
> > > diff --git a/arch/mips/kernel/scall.S b/arch/mips/kernel/scall.S
> > > new file mode 100644
> > > index 000000000000..7b35969151de
> > > --- /dev/null
> > > +++ b/arch/mips/kernel/scall.S
> > > @@ -0,0 +1,135 @@
> > > +/* SPDX-License-Identifier: GPL-2.0 */
> > > +/*
> > > + * Copyright (C) 1995, 96, 97, 98, 99, 2000, 01, 02 by Ralf Baechle
> > > + * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
> > > + * Copyright (C) 2001 MIPS Technologies, Inc.
> > > + * Copyright (C) 2004 Thiemo Seufer
> > > + * Copyright (C) 2014 Imagination Technologies Ltd.
> > > + */
> > > +#include <linux/errno.h>
> > > +#include <asm/asm.h>
> > > +#include <asm/asmmacro.h>
> > > +#include <asm/irqflags.h>
> > > +#include <asm/mipsregs.h>
> > > +#include <asm/regdef.h>
> > > +#include <asm/stackframe.h>
> > > +#include <asm/asm-offsets.h>
> > > +#include <asm/sysmips.h>
> > > +#include <asm/thread_info.h>
> > > +#include <asm/unistd.h>
> > > +#include <asm/war.h>
> > > +
> > > +     .align  5
> > > +NESTED(handle_sys, PT_SIZE, sp)
> > > +     .set    noat
> > > +     SAVE_SOME
> > > +     SAVE_STATIC
> > > +     CLI
> > > +     .set    at
> > > +
> > > +     move    a0, sp
> > > +     jal     do_syscall
> > > +
> > > +     .set    noat
> > > +     RESTORE_TEMP
> > > +     RESTORE_AT
> > > +     RESTORE_STATIC
> > > +     RESTORE_SOME
> > > +     RESTORE_SP_AND_RET
> > > +     .set    at
> > > +     END(handle_sys)
> > > +
> > > +#ifdef CONFIG_32BIT
> > > +LEAF(sys_syscall)
> > > +     subu    t0, a0, __NR_O32_Linux          # check syscall number
> > > +     sltiu   v0, t0, __NR_O32_Linux_syscalls
> > > +     beqz    t0, einval                      # do not recurse
> > > +     sll     t1, t0, 2
> > > +     beqz    v0, einval
> > > +     lw      t2, sys_call_table(t1)          # syscall routine
> > > +
> > > +     move    a0, a1                          # shift argument registers
> > > +     move    a1, a2
> > > +     move    a2, a3
> > > +     lw      a3, 16(sp)
> > > +     lw      t4, 20(sp)
> > > +     lw      t5, 24(sp)
> > > +     lw      t6, 28(sp)
> > > +     sw      t4, 16(sp)
> > > +     sw      t5, 20(sp)
> > > +     sw      t6, 24(sp)
> > > +     jr      t2
> > > +     /* Unreached */
> > > +
> > > +einval: li   v0, -ENOSYS
> > > +     jr      ra
> > > +     END(sys_syscall)
> > > +
> > > +#ifdef CONFIG_MIPS_MT_FPAFF
> > > +     /*
> > > +      * For FPU affinity scheduling on MIPS MT processors, we need to
> > > +      * intercept sys_sched_xxxaffinity() calls until we get a proper hook
> > > +      * in kernel/sched/core.c.  Considered only temporary we only support
> > > +      * these hooks for the 32-bit kernel - there is no MIPS64 MT processor
> > > +      * atm.
> > > +      */
> > > +#define sys_sched_setaffinity        mipsmt_sys_sched_setaffinity
> > > +#define sys_sched_getaffinity        mipsmt_sys_sched_getaffinity
> > > +#endif /* CONFIG_MIPS_MT_FPAFF */
> > > +
> > > +#define __SYSCALL_WITH_COMPAT(nr, native, compat)    __SYSCALL(nr, native)
> > > +#define __SYSCALL(nr, entry)         PTR entry
> > > +     .align  2
> > > +     .type   sys_call_table, @object
> > > +EXPORT(sys_call_table)
> > > +#include <asm/syscall_table_o32.h>
> > > +#endif /* CONFIG_32BIT */
> > > +
> > > +#ifdef CONFIG_64BIT
> > > +#ifdef CONFIG_MIPS32_O32
> > > +LEAF(sys32_syscall)
> > > +     subu    t0, a0, __NR_O32_Linux          # check syscall number
> > > +     sltiu   v0, t0, __NR_O32_Linux_syscalls
> > > +     beqz    t0, einval                      # do not recurse
> > > +     dsll    t1, t0, 3
> > > +     beqz    v0, einval
> > > +     ld      t2, sys32_call_table(t1)        # syscall routine
> > > +
> > > +     move    a0, a1                          # shift argument registers
> > > +     move    a1, a2
> > > +     move    a2, a3
> > > +     move    a3, a4
> > > +     move    a4, a5
> > > +     move    a5, a6
> > > +     move    a6, a7
> > > +     jr      t2
> > > +     /* Unreached */
> > > +
> > > +einval: li   v0, -ENOSYS
> > > +     jr      ra
> > > +     END(sys32_syscall)
> > > +
> > > +#define __SYSCALL_WITH_COMPAT(nr, native, compat)    __SYSCALL(nr, compat)
> > > +#define __SYSCALL(nr, entry) PTR entry
> > > +     .align  3
> > > +     .type   sys32_call_table,@object
> > > +EXPORT(sys32_call_table)
> > > +#include <asm/syscall_table_o32.h>
> > > +#endif /* CONFIG_MIPS32_O32 */
> > > +
> > > +#ifdef CONFIG_MIPS32_N32
> > > +#undef __SYSCALL
> > > +#define __SYSCALL(nr, entry) PTR entry
> > > +     .align  3
> > > +     .type   sysn32_call_table, @object
> > > +EXPORT(sysn32_call_table)
> > > +#include <asm/syscall_table_n32.h>
> > > +#endif /* CONFIG_MIPS32_N32 */
> > > +
> > > +#undef __SYSCALL
> > > +#define __SYSCALL(nr, entry) PTR entry
> > > +     .align  3
> > > +     .type   sys_call_table, @object
> > > +EXPORT(sys_call_table)
> > > +#include <asm/syscall_table_n64.h>
> > > +#endif /* CONFIG_64BIT */
> > > diff --git a/arch/mips/kernel/scall32-o32.S b/arch/mips/kernel/scall32-o32.S
> > > deleted file mode 100644
> > > index b1b2e106f711..000000000000
> > > --- a/arch/mips/kernel/scall32-o32.S
> > > +++ /dev/null
> > > @@ -1,223 +0,0 @@
> > > -/*
> > > - * This file is subject to the terms and conditions of the GNU General Public
> > > - * License.  See the file "COPYING" in the main directory of this archive
> > > - * for more details.
> > > - *
> > > - * Copyright (C) 1995-99, 2000- 02, 06 Ralf Baechle <ralf@linux-mips.org>
> > > - * Copyright (C) 2001 MIPS Technologies, Inc.
> > > - * Copyright (C) 2004 Thiemo Seufer
> > > - * Copyright (C) 2014 Imagination Technologies Ltd.
> > > - */
> > > -#include <linux/errno.h>
> > > -#include <asm/asm.h>
> > > -#include <asm/asmmacro.h>
> > > -#include <asm/irqflags.h>
> > > -#include <asm/mipsregs.h>
> > > -#include <asm/regdef.h>
> > > -#include <asm/stackframe.h>
> > > -#include <asm/isadep.h>
> > > -#include <asm/sysmips.h>
> > > -#include <asm/thread_info.h>
> > > -#include <asm/unistd.h>
> > > -#include <asm/war.h>
> > > -#include <asm/asm-offsets.h>
> > > -
> > > -     .align  5
> > > -NESTED(handle_sys, PT_SIZE, sp)
> > > -     .set    noat
> > > -     SAVE_SOME
> > > -     TRACE_IRQS_ON_RELOAD
> > > -     STI
> > > -     .set    at
> > > -
> > > -     lw      t1, PT_EPC(sp)          # skip syscall on return
> > > -
> > > -     addiu   t1, 4                   # skip to next instruction
> > > -     sw      t1, PT_EPC(sp)
> > > -
> > > -     sw      a3, PT_R26(sp)          # save a3 for syscall restarting
> > > -
> > > -     /*
> > > -      * More than four arguments.  Try to deal with it by copying the
> > > -      * stack arguments from the user stack to the kernel stack.
> > > -      * This Sucks (TM).
> > > -      */
> > > -     lw      t0, PT_R29(sp)          # get old user stack pointer
> > > -
> > > -     /*
> > > -      * We intentionally keep the kernel stack a little below the top of
> > > -      * userspace so we don't have to do a slower byte accurate check here.
> > > -      */
> > > -     addu    t4, t0, 32
> > > -     bltz    t4, bad_stack           # -> sp is bad
> > > -
> > > -     /*
> > > -      * Ok, copy the args from the luser stack to the kernel stack.
> > > -      */
> > > -
> > > -     .set    push
> > > -     .set    noreorder
> > > -     .set    nomacro
> > > -
> > > -load_a4: user_lw(t5, 16(t0))         # argument #5 from usp
> > > -load_a5: user_lw(t6, 20(t0))         # argument #6 from usp
> > > -load_a6: user_lw(t7, 24(t0))         # argument #7 from usp
> > > -load_a7: user_lw(t8, 28(t0))         # argument #8 from usp
> > > -loads_done:
> > > -
> > > -     sw      t5, 16(sp)              # argument #5 to ksp
> > > -     sw      t6, 20(sp)              # argument #6 to ksp
> > > -     sw      t7, 24(sp)              # argument #7 to ksp
> > > -     sw      t8, 28(sp)              # argument #8 to ksp
> > > -     .set    pop
> > > -
> > > -     .section __ex_table,"a"
> > > -     PTR     load_a4, bad_stack_a4
> > > -     PTR     load_a5, bad_stack_a5
> > > -     PTR     load_a6, bad_stack_a6
> > > -     PTR     load_a7, bad_stack_a7
> > > -     .previous
> > > -
> > > -     lw      t0, TI_FLAGS($28)       # syscall tracing enabled?
> > > -     li      t1, _TIF_WORK_SYSCALL_ENTRY
> > > -     and     t0, t1
> > > -     bnez    t0, syscall_trace_entry # -> yes
> > > -syscall_common:
> > > -     subu    v0, v0, __NR_O32_Linux  # check syscall number
> > > -     sltiu   t0, v0, __NR_O32_Linux_syscalls
> > > -     beqz    t0, illegal_syscall
> > > -
> > > -     sll     t0, v0, 2
> > > -     la      t1, sys_call_table
> > > -     addu    t1, t0
> > > -     lw      t2, (t1)                # syscall routine
> > > -
> > > -     beqz    t2, illegal_syscall
> > > -
> > > -     jalr    t2                      # Do The Real Thing (TM)
> > > -
> > > -     li      t0, -EMAXERRNO - 1      # error?
> > > -     sltu    t0, t0, v0
> > > -     sw      t0, PT_R7(sp)           # set error flag
> > > -     beqz    t0, 1f
> > > -
> > > -     lw      t1, PT_R2(sp)           # syscall number
> > > -     negu    v0                      # error
> > > -     sw      t1, PT_R0(sp)           # save it for syscall restarting
> > > -1:   sw      v0, PT_R2(sp)           # result
> > > -
> > > -o32_syscall_exit:
> > > -     j       syscall_exit_partial
> > > -
> > > -/* ------------------------------------------------------------------------ */
> > > -
> > > -syscall_trace_entry:
> > > -     SAVE_STATIC
> > > -     move    a0, sp
> > > -
> > > -     /*
> > > -      * syscall number is in v0 unless we called syscall(__NR_###)
> > > -      * where the real syscall number is in a0
> > > -      */
> > > -     move    a1, v0
> > > -     subu    t2, v0,  __NR_O32_Linux
> > > -     bnez    t2, 1f /* __NR_syscall at offset 0 */
> > > -     lw      a1, PT_R4(sp)
> > > -
> > > -1:   jal     syscall_trace_enter
> > > -
> > > -     bltz    v0, 1f                  # seccomp failed? Skip syscall
> > > -
> > > -     RESTORE_STATIC
> > > -     lw      v0, PT_R2(sp)           # Restore syscall (maybe modified)
> > > -     lw      a0, PT_R4(sp)           # Restore argument registers
> > > -     lw      a1, PT_R5(sp)
> > > -     lw      a2, PT_R6(sp)
> > > -     lw      a3, PT_R7(sp)
> > > -     j       syscall_common
> > > -
> > > -1:   j       syscall_exit
> > > -
> > > -/* ------------------------------------------------------------------------ */
> > > -
> > > -     /*
> > > -      * Our open-coded access area sanity test for the stack pointer
> > > -      * failed. We probably should handle this case a bit more drastic.
> > > -      */
> > > -bad_stack:
> > > -     li      v0, EFAULT
> > > -     sw      v0, PT_R2(sp)
> > > -     li      t0, 1                           # set error flag
> > > -     sw      t0, PT_R7(sp)
> > > -     j       o32_syscall_exit
> > > -
> > > -bad_stack_a4:
> > > -     li      t5, 0
> > > -     b       load_a5
> > > -
> > > -bad_stack_a5:
> > > -     li      t6, 0
> > > -     b       load_a6
> > > -
> > > -bad_stack_a6:
> > > -     li      t7, 0
> > > -     b       load_a7
> > > -
> > > -bad_stack_a7:
> > > -     li      t8, 0
> > > -     b       loads_done
> > > -
> > > -     /*
> > > -      * The system call does not exist in this kernel
> > > -      */
> > > -illegal_syscall:
> > > -     li      v0, ENOSYS                      # error
> > > -     sw      v0, PT_R2(sp)
> > > -     li      t0, 1                           # set error flag
> > > -     sw      t0, PT_R7(sp)
> > > -     j       o32_syscall_exit
> > > -     END(handle_sys)
> > > -
> > > -     LEAF(sys_syscall)
> > > -     subu    t0, a0, __NR_O32_Linux  # check syscall number
> > > -     sltiu   v0, t0, __NR_O32_Linux_syscalls
> > > -     beqz    t0, einval              # do not recurse
> > > -     sll     t1, t0, 2
> > > -     beqz    v0, einval
> > > -     lw      t2, sys_call_table(t1)          # syscall routine
> > > -
> > > -     move    a0, a1                          # shift argument registers
> > > -     move    a1, a2
> > > -     move    a2, a3
> > > -     lw      a3, 16(sp)
> > > -     lw      t4, 20(sp)
> > > -     lw      t5, 24(sp)
> > > -     lw      t6, 28(sp)
> > > -     sw      t4, 16(sp)
> > > -     sw      t5, 20(sp)
> > > -     sw      t6, 24(sp)
> > > -     jr      t2
> > > -     /* Unreached */
> > > -
> > > -einval: li   v0, -ENOSYS
> > > -     jr      ra
> > > -     END(sys_syscall)
> > > -
> > > -#ifdef CONFIG_MIPS_MT_FPAFF
> > > -     /*
> > > -      * For FPU affinity scheduling on MIPS MT processors, we need to
> > > -      * intercept sys_sched_xxxaffinity() calls until we get a proper hook
> > > -      * in kernel/sched/core.c.  Considered only temporary we only support
> > > -      * these hooks for the 32-bit kernel - there is no MIPS64 MT processor
> > > -      * atm.
> > > -      */
> > > -#define sys_sched_setaffinity        mipsmt_sys_sched_setaffinity
> > > -#define sys_sched_getaffinity        mipsmt_sys_sched_getaffinity
> > > -#endif /* CONFIG_MIPS_MT_FPAFF */
> > > -
> > > -#define __SYSCALL_WITH_COMPAT(nr, native, compat)    __SYSCALL(nr, native)
> > > -#define __SYSCALL(nr, entry)         PTR entry
> > > -     .align  2
> > > -     .type   sys_call_table, @object
> > > -EXPORT(sys_call_table)
> > > -#include <asm/syscall_table_o32.h>
> > > diff --git a/arch/mips/kernel/scall64-n32.S b/arch/mips/kernel/scall64-n32.S
> > > deleted file mode 100644
> > > index f650c55a17dc..000000000000
> > > --- a/arch/mips/kernel/scall64-n32.S
> > > +++ /dev/null
> > > @@ -1,107 +0,0 @@
> > > -/*
> > > - * This file is subject to the terms and conditions of the GNU General Public
> > > - * License.  See the file "COPYING" in the main directory of this archive
> > > - * for more details.
> > > - *
> > > - * Copyright (C) 1995, 96, 97, 98, 99, 2000, 01 by Ralf Baechle
> > > - * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
> > > - * Copyright (C) 2001 MIPS Technologies, Inc.
> > > - */
> > > -#include <linux/errno.h>
> > > -#include <asm/asm.h>
> > > -#include <asm/asmmacro.h>
> > > -#include <asm/irqflags.h>
> > > -#include <asm/mipsregs.h>
> > > -#include <asm/regdef.h>
> > > -#include <asm/stackframe.h>
> > > -#include <asm/thread_info.h>
> > > -#include <asm/unistd.h>
> > > -
> > > -#ifndef CONFIG_MIPS32_O32
> > > -/* No O32, so define handle_sys here */
> > > -#define handle_sysn32 handle_sys
> > > -#endif
> > > -
> > > -     .align  5
> > > -NESTED(handle_sysn32, PT_SIZE, sp)
> > > -#ifndef CONFIG_MIPS32_O32
> > > -     .set    noat
> > > -     SAVE_SOME
> > > -     TRACE_IRQS_ON_RELOAD
> > > -     STI
> > > -     .set    at
> > > -#endif
> > > -
> > > -     dsubu   t0, v0, __NR_N32_Linux  # check syscall number
> > > -     sltiu   t0, t0, __NR_N32_Linux_syscalls
> > > -
> > > -#ifndef CONFIG_MIPS32_O32
> > > -     ld      t1, PT_EPC(sp)          # skip syscall on return
> > > -     daddiu  t1, 4                   # skip to next instruction
> > > -     sd      t1, PT_EPC(sp)
> > > -#endif
> > > -     beqz    t0, not_n32_scall
> > > -
> > > -     sd      a3, PT_R26(sp)          # save a3 for syscall restarting
> > > -
> > > -     li      t1, _TIF_WORK_SYSCALL_ENTRY
> > > -     LONG_L  t0, TI_FLAGS($28)       # syscall tracing enabled?
> > > -     and     t0, t1, t0
> > > -     bnez    t0, n32_syscall_trace_entry
> > > -
> > > -syscall_common:
> > > -     dsll    t0, v0, 3               # offset into table
> > > -     ld      t2, (sysn32_call_table - (__NR_N32_Linux * 8))(t0)
> > > -
> > > -     jalr    t2                      # Do The Real Thing (TM)
> > > -
> > > -     li      t0, -EMAXERRNO - 1      # error?
> > > -     sltu    t0, t0, v0
> > > -     sd      t0, PT_R7(sp)           # set error flag
> > > -     beqz    t0, 1f
> > > -
> > > -     ld      t1, PT_R2(sp)           # syscall number
> > > -     dnegu   v0                      # error
> > > -     sd      t1, PT_R0(sp)           # save it for syscall restarting
> > > -1:   sd      v0, PT_R2(sp)           # result
> > > -
> > > -     j       syscall_exit_partial
> > > -
> > > -/* ------------------------------------------------------------------------ */
> > > -
> > > -n32_syscall_trace_entry:
> > > -     SAVE_STATIC
> > > -     move    a0, sp
> > > -     move    a1, v0
> > > -     jal     syscall_trace_enter
> > > -
> > > -     bltz    v0, 1f                  # seccomp failed? Skip syscall
> > > -
> > > -     RESTORE_STATIC
> > > -     ld      v0, PT_R2(sp)           # Restore syscall (maybe modified)
> > > -     ld      a0, PT_R4(sp)           # Restore argument registers
> > > -     ld      a1, PT_R5(sp)
> > > -     ld      a2, PT_R6(sp)
> > > -     ld      a3, PT_R7(sp)
> > > -     ld      a4, PT_R8(sp)
> > > -     ld      a5, PT_R9(sp)
> > > -
> > > -     dsubu   t2, v0, __NR_N32_Linux  # check (new) syscall number
> > > -     sltiu   t0, t2, __NR_N32_Linux_syscalls
> > > -     beqz    t0, not_n32_scall
> > > -
> > > -     j       syscall_common
> > > -
> > > -1:   j       syscall_exit
> > > -
> > > -not_n32_scall:
> > > -     /* This is not an n32 compatibility syscall, pass it on to
> > > -        the n64 syscall handlers.  */
> > > -     j       handle_sys64
> > > -
> > > -     END(handle_sysn32)
> > > -
> > > -#define __SYSCALL(nr, entry) PTR entry
> > > -     .type   sysn32_call_table, @object
> > > -EXPORT(sysn32_call_table)
> > > -#include <asm/syscall_table_n32.h>
> > > diff --git a/arch/mips/kernel/scall64-n64.S b/arch/mips/kernel/scall64-n64.S
> > > deleted file mode 100644
> > > index 5d7bfc65e4d0..000000000000
> > > --- a/arch/mips/kernel/scall64-n64.S
> > > +++ /dev/null
> > > @@ -1,116 +0,0 @@
> > > -/*
> > > - * This file is subject to the terms and conditions of the GNU General Public
> > > - * License.  See the file "COPYING" in the main directory of this archive
> > > - * for more details.
> > > - *
> > > - * Copyright (C) 1995, 96, 97, 98, 99, 2000, 01, 02 by Ralf Baechle
> > > - * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
> > > - * Copyright (C) 2001 MIPS Technologies, Inc.
> > > - */
> > > -#include <linux/errno.h>
> > > -#include <asm/asm.h>
> > > -#include <asm/asmmacro.h>
> > > -#include <asm/irqflags.h>
> > > -#include <asm/mipsregs.h>
> > > -#include <asm/regdef.h>
> > > -#include <asm/stackframe.h>
> > > -#include <asm/asm-offsets.h>
> > > -#include <asm/sysmips.h>
> > > -#include <asm/thread_info.h>
> > > -#include <asm/unistd.h>
> > > -#include <asm/war.h>
> > > -
> > > -#ifndef CONFIG_MIPS32_COMPAT
> > > -/* Neither O32 nor N32, so define handle_sys here */
> > > -#define handle_sys64 handle_sys
> > > -#endif
> > > -
> > > -     .align  5
> > > -NESTED(handle_sys64, PT_SIZE, sp)
> > > -#if !defined(CONFIG_MIPS32_O32) && !defined(CONFIG_MIPS32_N32)
> > > -     /*
> > > -      * When 32-bit compatibility is configured scall_o32.S
> > > -      * already did this.
> > > -      */
> > > -     .set    noat
> > > -     SAVE_SOME
> > > -     TRACE_IRQS_ON_RELOAD
> > > -     STI
> > > -     .set    at
> > > -#endif
> > > -
> > > -#if !defined(CONFIG_MIPS32_O32) && !defined(CONFIG_MIPS32_N32)
> > > -     ld      t1, PT_EPC(sp)          # skip syscall on return
> > > -     daddiu  t1, 4                   # skip to next instruction
> > > -     sd      t1, PT_EPC(sp)
> > > -#endif
> > > -
> > > -     sd      a3, PT_R26(sp)          # save a3 for syscall restarting
> > > -
> > > -     li      t1, _TIF_WORK_SYSCALL_ENTRY
> > > -     LONG_L  t0, TI_FLAGS($28)       # syscall tracing enabled?
> > > -     and     t0, t1, t0
> > > -     bnez    t0, syscall_trace_entry
> > > -
> > > -syscall_common:
> > > -     dsubu   t2, v0, __NR_64_Linux
> > > -     sltiu   t0, t2, __NR_64_Linux_syscalls
> > > -     beqz    t0, illegal_syscall
> > > -
> > > -     dsll    t0, t2, 3               # offset into table
> > > -     dla     t2, sys_call_table
> > > -     daddu   t0, t2, t0
> > > -     ld      t2, (t0)                # syscall routine
> > > -     beqz    t2, illegal_syscall
> > > -
> > > -     jalr    t2                      # Do The Real Thing (TM)
> > > -
> > > -     li      t0, -EMAXERRNO - 1      # error?
> > > -     sltu    t0, t0, v0
> > > -     sd      t0, PT_R7(sp)           # set error flag
> > > -     beqz    t0, 1f
> > > -
> > > -     ld      t1, PT_R2(sp)           # syscall number
> > > -     dnegu   v0                      # error
> > > -     sd      t1, PT_R0(sp)           # save it for syscall restarting
> > > -1:   sd      v0, PT_R2(sp)           # result
> > > -
> > > -n64_syscall_exit:
> > > -     j       syscall_exit_partial
> > > -
> > > -/* ------------------------------------------------------------------------ */
> > > -
> > > -syscall_trace_entry:
> > > -     SAVE_STATIC
> > > -     move    a0, sp
> > > -     move    a1, v0
> > > -     jal     syscall_trace_enter
> > > -
> > > -     bltz    v0, 1f                  # seccomp failed? Skip syscall
> > > -
> > > -     RESTORE_STATIC
> > > -     ld      v0, PT_R2(sp)           # Restore syscall (maybe modified)
> > > -     ld      a0, PT_R4(sp)           # Restore argument registers
> > > -     ld      a1, PT_R5(sp)
> > > -     ld      a2, PT_R6(sp)
> > > -     ld      a3, PT_R7(sp)
> > > -     ld      a4, PT_R8(sp)
> > > -     ld      a5, PT_R9(sp)
> > > -     j       syscall_common
> > > -
> > > -1:   j       syscall_exit
> > > -
> > > -illegal_syscall:
> > > -     /* This also isn't a 64-bit syscall, throw an error.  */
> > > -     li      v0, ENOSYS                      # error
> > > -     sd      v0, PT_R2(sp)
> > > -     li      t0, 1                           # set error flag
> > > -     sd      t0, PT_R7(sp)
> > > -     j       n64_syscall_exit
> > > -     END(handle_sys64)
> > > -
> > > -#define __SYSCALL(nr, entry) PTR entry
> > > -     .align  3
> > > -     .type   sys_call_table, @object
> > > -EXPORT(sys_call_table)
> > > -#include <asm/syscall_table_n64.h>
> > > diff --git a/arch/mips/kernel/scall64-o32.S b/arch/mips/kernel/scall64-o32.S
> > > deleted file mode 100644
> > > index cedc8bd88804..000000000000
> > > --- a/arch/mips/kernel/scall64-o32.S
> > > +++ /dev/null
> > > @@ -1,221 +0,0 @@
> > > -/*
> > > - * This file is subject to the terms and conditions of the GNU General Public
> > > - * License.  See the file "COPYING" in the main directory of this archive
> > > - * for more details.
> > > - *
> > > - * Copyright (C) 1995 - 2000, 2001 by Ralf Baechle
> > > - * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
> > > - * Copyright (C) 2001 MIPS Technologies, Inc.
> > > - * Copyright (C) 2004 Thiemo Seufer
> > > - *
> > > - * Hairy, the userspace application uses a different argument passing
> > > - * convention than the kernel, so we have to translate things from o32
> > > - * to ABI64 calling convention.       64-bit syscalls are also processed
> > > - * here for now.
> > > - */
> > > -#include <linux/errno.h>
> > > -#include <asm/asm.h>
> > > -#include <asm/asmmacro.h>
> > > -#include <asm/irqflags.h>
> > > -#include <asm/mipsregs.h>
> > > -#include <asm/regdef.h>
> > > -#include <asm/stackframe.h>
> > > -#include <asm/thread_info.h>
> > > -#include <asm/unistd.h>
> > > -#include <asm/sysmips.h>
> > > -
> > > -     .align  5
> > > -NESTED(handle_sys, PT_SIZE, sp)
> > > -     .set    noat
> > > -     SAVE_SOME
> > > -     TRACE_IRQS_ON_RELOAD
> > > -     STI
> > > -     .set    at
> > > -     ld      t1, PT_EPC(sp)          # skip syscall on return
> > > -
> > > -     dsubu   t0, v0, __NR_O32_Linux  # check syscall number
> > > -     sltiu   t0, t0, __NR_O32_Linux_syscalls
> > > -     daddiu  t1, 4                   # skip to next instruction
> > > -     sd      t1, PT_EPC(sp)
> > > -     beqz    t0, not_o32_scall
> > > -#if 0
> > > - SAVE_ALL
> > > - move a1, v0
> > > - ASM_PRINT("Scall %ld\n")
> > > - RESTORE_ALL
> > > -#endif
> > > -
> > > -     /* We don't want to stumble over broken sign extensions from
> > > -        userland. O32 does never use the upper half. */
> > > -     sll     a0, a0, 0
> > > -     sll     a1, a1, 0
> > > -     sll     a2, a2, 0
> > > -     sll     a3, a3, 0
> > > -
> > > -     sd      a3, PT_R26(sp)          # save a3 for syscall restarting
> > > -
> > > -     /*
> > > -      * More than four arguments.  Try to deal with it by copying the
> > > -      * stack arguments from the user stack to the kernel stack.
> > > -      * This Sucks (TM).
> > > -      *
> > > -      * We intentionally keep the kernel stack a little below the top of
> > > -      * userspace so we don't have to do a slower byte accurate check here.
> > > -      */
> > > -     ld      t0, PT_R29(sp)          # get old user stack pointer
> > > -     daddu   t1, t0, 32
> > > -     bltz    t1, bad_stack
> > > -
> > > -load_a4: lw  a4, 16(t0)              # argument #5 from usp
> > > -load_a5: lw  a5, 20(t0)              # argument #6 from usp
> > > -load_a6: lw  a6, 24(t0)              # argument #7 from usp
> > > -load_a7: lw  a7, 28(t0)              # argument #8 from usp
> > > -loads_done:
> > > -
> > > -     .section __ex_table,"a"
> > > -     PTR     load_a4, bad_stack_a4
> > > -     PTR     load_a5, bad_stack_a5
> > > -     PTR     load_a6, bad_stack_a6
> > > -     PTR     load_a7, bad_stack_a7
> > > -     .previous
> > > -
> > > -     li      t1, _TIF_WORK_SYSCALL_ENTRY
> > > -     LONG_L  t0, TI_FLAGS($28)       # syscall tracing enabled?
> > > -     and     t0, t1, t0
> > > -     bnez    t0, trace_a_syscall
> > > -
> > > -syscall_common:
> > > -     dsll    t0, v0, 3               # offset into table
> > > -     ld      t2, (sys32_call_table - (__NR_O32_Linux * 8))(t0)
> > > -
> > > -     jalr    t2                      # Do The Real Thing (TM)
> > > -
> > > -     li      t0, -EMAXERRNO - 1      # error?
> > > -     sltu    t0, t0, v0
> > > -     sd      t0, PT_R7(sp)           # set error flag
> > > -     beqz    t0, 1f
> > > -
> > > -     ld      t1, PT_R2(sp)           # syscall number
> > > -     dnegu   v0                      # error
> > > -     sd      t1, PT_R0(sp)           # save it for syscall restarting
> > > -1:   sd      v0, PT_R2(sp)           # result
> > > -
> > > -o32_syscall_exit:
> > > -     j       syscall_exit_partial
> > > -
> > > -/* ------------------------------------------------------------------------ */
> > > -
> > > -trace_a_syscall:
> > > -     SAVE_STATIC
> > > -     sd      a4, PT_R8(sp)           # Save argument registers
> > > -     sd      a5, PT_R9(sp)
> > > -     sd      a6, PT_R10(sp)
> > > -     sd      a7, PT_R11(sp)          # For indirect syscalls
> > > -
> > > -     move    a0, sp
> > > -     /*
> > > -      * absolute syscall number is in v0 unless we called syscall(__NR_###)
> > > -      * where the real syscall number is in a0
> > > -      * note: NR_syscall is the first O32 syscall but the macro is
> > > -      * only defined when compiling with -mabi=32 (CONFIG_32BIT)
> > > -      * therefore __NR_O32_Linux is used (4000)
> > > -      */
> > > -     .set    push
> > > -     .set    reorder
> > > -     subu    t1, v0,  __NR_O32_Linux
> > > -     move    a1, v0
> > > -     bnez    t1, 1f /* __NR_syscall at offset 0 */
> > > -     ld      a1, PT_R4(sp) /* Arg1 for __NR_syscall case */
> > > -     .set    pop
> > > -
> > > -1:   jal     syscall_trace_enter
> > > -
> > > -     bltz    v0, 1f                  # seccomp failed? Skip syscall
> > > -
> > > -     RESTORE_STATIC
> > > -     ld      v0, PT_R2(sp)           # Restore syscall (maybe modified)
> > > -     ld      a0, PT_R4(sp)           # Restore argument registers
> > > -     ld      a1, PT_R5(sp)
> > > -     ld      a2, PT_R6(sp)
> > > -     ld      a3, PT_R7(sp)
> > > -     ld      a4, PT_R8(sp)
> > > -     ld      a5, PT_R9(sp)
> > > -     ld      a6, PT_R10(sp)
> > > -     ld      a7, PT_R11(sp)          # For indirect syscalls
> > > -
> > > -     dsubu   t0, v0, __NR_O32_Linux  # check (new) syscall number
> > > -     sltiu   t0, t0, __NR_O32_Linux_syscalls
> > > -     beqz    t0, not_o32_scall
> > > -
> > > -     j       syscall_common
> > > -
> > > -1:   j       syscall_exit
> > > -
> > > -/* ------------------------------------------------------------------------ */
> > > -
> > > -     /*
> > > -      * The stackpointer for a call with more than 4 arguments is bad.
> > > -      */
> > > -bad_stack:
> > > -     li      v0, EFAULT
> > > -     sd      v0, PT_R2(sp)
> > > -     li      t0, 1                   # set error flag
> > > -     sd      t0, PT_R7(sp)
> > > -     j       o32_syscall_exit
> > > -
> > > -bad_stack_a4:
> > > -     li      a4, 0
> > > -     b       load_a5
> > > -
> > > -bad_stack_a5:
> > > -     li      a5, 0
> > > -     b       load_a6
> > > -
> > > -bad_stack_a6:
> > > -     li      a6, 0
> > > -     b       load_a7
> > > -
> > > -bad_stack_a7:
> > > -     li      a7, 0
> > > -     b       loads_done
> > > -
> > > -not_o32_scall:
> > > -     /*
> > > -      * This is not an o32 compatibility syscall, pass it on
> > > -      * to the 64-bit syscall handlers.
> > > -      */
> > > -#ifdef CONFIG_MIPS32_N32
> > > -     j       handle_sysn32
> > > -#else
> > > -     j       handle_sys64
> > > -#endif
> > > -     END(handle_sys)
> > > -
> > > -LEAF(sys32_syscall)
> > > -     subu    t0, a0, __NR_O32_Linux  # check syscall number
> > > -     sltiu   v0, t0, __NR_O32_Linux_syscalls
> > > -     beqz    t0, einval              # do not recurse
> > > -     dsll    t1, t0, 3
> > > -     beqz    v0, einval
> > > -     ld      t2, sys32_call_table(t1)                # syscall routine
> > > -
> > > -     move    a0, a1                  # shift argument registers
> > > -     move    a1, a2
> > > -     move    a2, a3
> > > -     move    a3, a4
> > > -     move    a4, a5
> > > -     move    a5, a6
> > > -     move    a6, a7
> > > -     jr      t2
> > > -     /* Unreached */
> > > -
> > > -einval: li   v0, -ENOSYS
> > > -     jr      ra
> > > -     END(sys32_syscall)
> > > -
> > > -#define __SYSCALL_WITH_COMPAT(nr, native, compat)    __SYSCALL(nr, compat)
> > > -#define __SYSCALL(nr, entry) PTR entry
> > > -     .align  3
> > > -     .type   sys32_call_table,@object
> > > -EXPORT(sys32_call_table)
> > > -#include <asm/syscall_table_o32.h>
> > > diff --git a/arch/mips/kernel/signal.c b/arch/mips/kernel/signal.c
> > > index f1e985109da0..1ec6a0cf1163 100644
> > > --- a/arch/mips/kernel/signal.c
> > > +++ b/arch/mips/kernel/signal.c
> > > @@ -32,7 +32,6 @@
> > >   #include <linux/bitops.h>
> > >   #include <asm/cacheflush.h>
> > >   #include <asm/fpu.h>
> > > -#include <asm/sim.h>
> > >   #include <asm/ucontext.h>
> > >   #include <asm/cpu-features.h>
> > >   #include <asm/war.h>
> > > @@ -627,7 +626,7 @@ SYSCALL_DEFINE3(sigaction, int, sig, const struct sigaction __user *, act,
> > >   #endif
> > >
> > >   #ifdef CONFIG_TRAD_SIGNALS
> > > -asmlinkage void sys_sigreturn(void)
> > > +asmlinkage long sys_sigreturn(void)
> > >   {
> > >       struct sigframe __user *frame;
> > >       struct pt_regs *regs;
> > > @@ -649,22 +648,16 @@ asmlinkage void sys_sigreturn(void)
> > >       else if (sig)
> > >               force_sig(sig);
> > >
> > > -     /*
> > > -      * Don't let your children do this ...
> > > -      */
> > > -     __asm__ __volatile__(
> > > -             "move\t$29, %0\n\t"
> > > -             "j\tsyscall_exit"
> > > -             : /* no outputs */
> > > -             : "r" (regs));
> > > -     /* Unreached */
> > > +     regs->regs[27] = 1;     /* return directly */
> > > +     return regs->regs[2];
> > >
> > >   badframe:
> > >       force_sig(SIGSEGV);
> > > +     return 0;
> > >   }
> > >   #endif /* CONFIG_TRAD_SIGNALS */
> > >
> > > -asmlinkage void sys_rt_sigreturn(void)
> > > +asmlinkage long sys_rt_sigreturn(void)
> > >   {
> > >       struct rt_sigframe __user *frame;
> > >       struct pt_regs *regs;
> > > @@ -689,18 +682,12 @@ asmlinkage void sys_rt_sigreturn(void)
> > >       if (restore_altstack(&frame->rs_uc.uc_stack))
> > >               goto badframe;
> > >
> > > -     /*
> > > -      * Don't let your children do this ...
> > > -      */
> > > -     __asm__ __volatile__(
> > > -             "move\t$29, %0\n\t"
> > > -             "j\tsyscall_exit"
> > > -             : /* no outputs */
> > > -             : "r" (regs));
> > > -     /* Unreached */
> > > +     regs->regs[27] = 1;     /* return directly */
> > > +     return regs->regs[2];
> > >
> > >   badframe:
> > >       force_sig(SIGSEGV);
> > > +     return 0;
> > >   }
> > >
> > >   #ifdef CONFIG_TRAD_SIGNALS
> > > @@ -852,11 +839,11 @@ static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
> > >       signal_setup_done(ret, ksig, 0);
> > >   }
> > >
> > > -static void do_signal(struct pt_regs *regs)
> > > +void arch_do_signal_or_restart(struct pt_regs *regs, bool has_signal)
> > >   {
> > >       struct ksignal ksig;
> > >
> > > -     if (get_signal(&ksig)) {
> > > +     if (has_signal && get_signal(&ksig)) {
> > >               /* Whee!  Actually deliver the signal.  */
> > >               handle_signal(&ksig, regs);
> > >               return;
> > > @@ -904,7 +891,7 @@ asmlinkage void do_notify_resume(struct pt_regs *regs, void *unused,
> > >
> > >       /* deal with pending signal delivery */
> > >       if (thread_info_flags & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL))
> > > -             do_signal(regs);
> > > +             arch_do_signal_or_restart(regs, thread_info_flags & _TIF_SIGPENDING);
> > >
> > >       if (thread_info_flags & _TIF_NOTIFY_RESUME) {
> > >               tracehook_notify_resume(regs);
> > > diff --git a/arch/mips/kernel/signal_n32.c b/arch/mips/kernel/signal_n32.c
> > > index 7bd00fad61af..b52b995a8a9b 100644
> > > --- a/arch/mips/kernel/signal_n32.c
> > > +++ b/arch/mips/kernel/signal_n32.c
> > > @@ -19,7 +19,6 @@
> > >   #include <asm/asm.h>
> > >   #include <asm/cacheflush.h>
> > >   #include <asm/compat-signal.h>
> > > -#include <asm/sim.h>
> > >   #include <linux/uaccess.h>
> > >   #include <asm/ucontext.h>
> > >   #include <asm/fpu.h>
> > > @@ -51,7 +50,7 @@ struct rt_sigframe_n32 {
> > >       struct ucontextn32 rs_uc;
> > >   };
> > >
> > > -asmlinkage void sysn32_rt_sigreturn(void)
> > > +asmlinkage long sysn32_rt_sigreturn(void)
> > >   {
> > >       struct rt_sigframe_n32 __user *frame;
> > >       struct pt_regs *regs;
> > > @@ -76,18 +75,12 @@ asmlinkage void sysn32_rt_sigreturn(void)
> > >       if (compat_restore_altstack(&frame->rs_uc.uc_stack))
> > >               goto badframe;
> > >
> > > -     /*
> > > -      * Don't let your children do this ...
> > > -      */
> > > -     __asm__ __volatile__(
> > > -             "move\t$29, %0\n\t"
> > > -             "j\tsyscall_exit"
> > > -             : /* no outputs */
> > > -             : "r" (regs));
> > > -     /* Unreached */
> > > +     regs->regs[27] = 1;     /* return directly */
> > > +     return regs->regs[2];
> > >
> > >   badframe:
> > >       force_sig(SIGSEGV);
> > > +     return 0;
> > >   }
> > >
> > >   static int setup_rt_frame_n32(void *sig_return, struct ksignal *ksig,
> > > diff --git a/arch/mips/kernel/signal_o32.c b/arch/mips/kernel/signal_o32.c
> > > index 299a7a28ca33..9245806e06f1 100644
> > > --- a/arch/mips/kernel/signal_o32.c
> > > +++ b/arch/mips/kernel/signal_o32.c
> > > @@ -17,7 +17,6 @@
> > >   #include <asm/abi.h>
> > >   #include <asm/compat-signal.h>
> > >   #include <asm/dsp.h>
> > > -#include <asm/sim.h>
> > >   #include <asm/unistd.h>
> > >
> > >   #include "signal-common.h"
> > > @@ -151,7 +150,7 @@ static int setup_frame_32(void *sig_return, struct ksignal *ksig,
> > >       return 0;
> > >   }
> > >
> > > -asmlinkage void sys32_rt_sigreturn(void)
> > > +asmlinkage long sys32_rt_sigreturn(void)
> > >   {
> > >       struct rt_sigframe32 __user *frame;
> > >       struct pt_regs *regs;
> > > @@ -176,18 +175,12 @@ asmlinkage void sys32_rt_sigreturn(void)
> > >       if (compat_restore_altstack(&frame->rs_uc.uc_stack))
> > >               goto badframe;
> > >
> > > -     /*
> > > -      * Don't let your children do this ...
> > > -      */
> > > -     __asm__ __volatile__(
> > > -             "move\t$29, %0\n\t"
> > > -             "j\tsyscall_exit"
> > > -             : /* no outputs */
> > > -             : "r" (regs));
> > > -     /* Unreached */
> > > +     regs->regs[27] = 1;     /* return directly */
> > > +     return regs->regs[2];
> > >
> > >   badframe:
> > >       force_sig(SIGSEGV);
> > > +     return 0;
> > >   }
> > >
> > >   static int setup_rt_frame_32(void *sig_return, struct ksignal *ksig,
> > > @@ -253,7 +246,7 @@ struct mips_abi mips_abi_32 = {
> > >   };
> > >
> > >
> > > -asmlinkage void sys32_sigreturn(void)
> > > +asmlinkage long sys32_sigreturn(void)
> > >   {
> > >       struct sigframe32 __user *frame;
> > >       struct pt_regs *regs;
> > > @@ -275,16 +268,10 @@ asmlinkage void sys32_sigreturn(void)
> > >       else if (sig)
> > >               force_sig(sig);
> > >
> > > -     /*
> > > -      * Don't let your children do this ...
> > > -      */
> > > -     __asm__ __volatile__(
> > > -             "move\t$29, %0\n\t"
> > > -             "j\tsyscall_exit"
> > > -             : /* no outputs */
> > > -             : "r" (regs));
> > > -     /* Unreached */
> > > +     regs->regs[27] = 1;     /* return directly */
> > > +     return regs->regs[2];
> > >
> > >   badframe:
> > >       force_sig(SIGSEGV);
> > > +     return 0;
> > >   }
> > > diff --git a/arch/mips/kernel/syscall.c b/arch/mips/kernel/syscall.c
> > > index 2afa3eef486a..6dc78648b274 100644
> > > --- a/arch/mips/kernel/syscall.c
> > > +++ b/arch/mips/kernel/syscall.c
> > > @@ -8,6 +8,7 @@
> > >    * Copyright (C) 2001 MIPS Technologies, Inc.
> > >    */
> > >   #include <linux/capability.h>
> > > +#include <linux/entry-common.h>
> > >   #include <linux/errno.h>
> > >   #include <linux/linkage.h>
> > >   #include <linux/fs.h>
> > > @@ -35,9 +36,9 @@
> > >   #include <asm/cacheflush.h>
> > >   #include <asm/asm-offsets.h>
> > >   #include <asm/signal.h>
> > > -#include <asm/sim.h>
> > >   #include <asm/shmparam.h>
> > >   #include <asm/sync.h>
> > > +#include <asm/syscall.h>
> > >   #include <asm/sysmips.h>
> > >   #include <asm/switch_to.h>
> > >
> > > @@ -79,10 +80,6 @@ SYSCALL_DEFINE6(mips_mmap2, unsigned long, addr, unsigned long, len,
> > >                              pgoff >> (PAGE_SHIFT - 12));
> > >   }
> > >
> > > -save_static_function(sys_fork);
> > > -save_static_function(sys_clone);
> > > -save_static_function(sys_clone3);
> > > -
> > >   SYSCALL_DEFINE1(set_thread_area, unsigned long, addr)
> > >   {
> > >       struct thread_info *ti = task_thread_info(current);
> > > @@ -182,28 +179,11 @@ static inline int mips_atomic_set(unsigned long addr, unsigned long new)
> > >               return err;
> > >
> > >       regs = current_pt_regs();
> > > -     regs->regs[2] = old;
> > > -     regs->regs[7] = 0;      /* No error */
> > > -
> > > -     /*
> > > -      * Don't let your children do this ...
> > > -      */
> > > -     __asm__ __volatile__(
> > > -     "       move    $29, %0                                         \n"
> > > -     "       j       syscall_exit                                    \n"
> > > -     : /* no outputs */
> > > -     : "r" (regs));
> > > -
> > > -     /* unreached.  Honestly.  */
> > > -     unreachable();
> > > +     regs->regs[7] = 0;      /* no error */
> > > +     regs->regs[27] = 1;     /* return directly */
> > > +     return old;
> > >   }
> > >
> > > -/*
> > > - * mips_atomic_set() normally returns directly via syscall_exit potentially
> > > - * clobbering static registers, so be sure to preserve them.
> > > - */
> > > -save_static_function(sys_sysmips);
> > > -
> > >   SYSCALL_DEFINE3(sysmips, long, cmd, long, arg1, long, arg2)
> > >   {
> > >       switch (cmd) {
> > > @@ -249,3 +229,120 @@ asmlinkage void bad_stack(void)
> > >   {
> > >       do_exit(SIGSEGV);
> > >   }
> > > +
> > > +#if defined(CONFIG_32BIT) || defined(CONFIG_MIPS32_O32)
> > > +static inline int get_args(struct pt_regs *regs)
> > > +{
> > > +     int *usp = (int *)regs->regs[29];
> > > +
> > > +#ifdef CONFIG_MIPS32_O32
> > > +     /*
> > > +      * Hairy, the userspace application uses a different argument passing
> > > +      * convention than the kernel, so we have to translate things from o32
> > > +      * to ABI64 calling convention.
> > > +      *
> > > +      * We don't want to stumble over broken sign extensions from userland.
> > > +      * O32 does never use the upper half.
> > > +      */
> > > +     regs->regs[4] = (int)regs->regs[4];
> > > +     regs->regs[5] = (int)regs->regs[5];
> > > +     regs->regs[6] = (int)regs->regs[6];
> > > +     regs->regs[7] = (int)regs->regs[7];
> > > +#endif
> > > +
> > > +     /*
> > > +      * More than four arguments.  Try to deal with it by copying the
> > > +      * stack arguments from the user stack to the kernel stack.
> > > +      * This Sucks (TM).
> > > +      *
> > > +      * We intentionally keep the kernel stack a little below the top of
> > > +      * userspace so we don't have to do a slower byte accurate check here.
> > > +      */
> > > +     if (!access_ok(usp, 32))
> > > +             return -1;
> > > +
> > > +     get_user(regs->regs[8], usp + 4);
> > > +     get_user(regs->regs[9], usp + 5);
> > > +     get_user(regs->regs[10], usp + 6);
> > > +     get_user(regs->regs[11], usp + 7);
> > > +
> > > +     return 0;
> > > +}
> > > +#endif
> > > +
> > > +typedef long (*sys_call_fn)(unsigned long, unsigned long,
> > > +     unsigned long, unsigned long, unsigned long, unsigned long);
> > > +
> > > +void noinstr do_syscall(struct pt_regs *regs)
> > > +{
> > > +     unsigned long nr;
> > > +     unsigned long ret;
> > > +     sys_call_fn syscall_fn = NULL;
> > > +
> > > +     nr = regs->regs[2];
> > > +     current_thread_info()->syscall = nr;
> > > +     nr = syscall_enter_from_user_mode(regs, nr);
> > > +
> > > +     regs->cp0_epc += 4;             /* skip syscall on return */
> > > +                                     /* skip to next instruction */
> > > +     regs->regs[26] = regs->regs[7]; /* save a3 for syscall restarting */
> > > +     regs->regs[27] = 0;             /* do not return directly */
> > > +
> > > +#ifdef CONFIG_32BIT
> > > +     if (nr >= __NR_O32_Linux && nr < __NR_O32_Linux + __NR_O32_Linux_syscalls) {
> > > +             if (get_args(regs) < 0) {
> > > +                     ret = EFAULT;
> > > +                     goto error;
> > > +             }
> > > +             syscall_fn = (sys_call_fn)sys_call_table[nr - __NR_O32_Linux];
> > > +     }
> > > +#endif
> > > +
> > > +#ifdef CONFIG_MIPS32_O32
> > > +     if (nr >= __NR_O32_Linux && nr < __NR_O32_Linux + __NR_O32_Linux_syscalls) {
> > > +             if (get_args(regs) < 0) {
> > > +                     ret = EFAULT;
> > > +                     goto error;
> > > +             }
> > > +             syscall_fn = (sys_call_fn)sys32_call_table[nr - __NR_O32_Linux];
> > > +     }
> > > +#endif
> > > +
> > > +#ifdef CONFIG_MIPS32_N32
> > > +     if (nr >= __NR_N32_Linux && nr < __NR_N32_Linux + __NR_N32_Linux_syscalls)
> > > +             syscall_fn = (sys_call_fn)sysn32_call_table[nr - __NR_N32_Linux];
> > > +#endif
> > > +
> > > +#ifdef CONFIG_64BIT
> > > +     if (nr >= __NR_64_Linux && nr < __NR_64_Linux + __NR_64_Linux_syscalls)
> > > +             syscall_fn = (sys_call_fn)sys_call_table[nr - __NR_64_Linux];
> > > +#endif
> > > +
> > > +     if (!syscall_fn) {
> > > +             ret = ENOSYS;
> > > +             goto error;
> > > +     }
> > > +
> > > +     ret = syscall_fn(regs->regs[4], regs->regs[5], regs->regs[6],
> > > +                      regs->regs[7], regs->regs[8], regs->regs[9]);
> > > +
> > > +     if (regs->regs[27])             /* return directly? */
> > > +             goto out;
> > > +
> > > +     regs->regs[7] = 0;              /* clear error flag */
> > > +     if (ret >= -EMAXERRNO - 1) {    /* error? */
> > > +             regs->regs[0] = nr;     /* save syscall number */
> > > +                                     /* for syscall restarting */
> > > +             ret = -ret;
> > > +             goto error;
> > > +     }
> > > +
> > > +     goto out;
> > > +
> > > +error:
> > > +     regs->regs[7] = 1;              /* set error flag */
> > > +
> > > +out:
> > > +     regs->regs[2] = ret;
> > > +     syscall_exit_to_user_mode(regs);
> > > +}
> > > diff --git a/arch/mips/kernel/syscalls/syscall_n32.tbl b/arch/mips/kernel/syscalls/syscall_n32.tbl
> > > index 70e32de2bcaa..d9ae765e51f1 100644
> > > --- a/arch/mips/kernel/syscalls/syscall_n32.tbl
> > > +++ b/arch/mips/kernel/syscalls/syscall_n32.tbl
> > > @@ -62,8 +62,8 @@
> > >   52  n32     socketpair                      sys_socketpair
> > >   53  n32     setsockopt                      sys_setsockopt
> > >   54  n32     getsockopt                      sys_getsockopt
> > > -55   n32     clone                           __sys_clone
> > > -56   n32     fork                            __sys_fork
> > > +55   n32     clone                           sys_clone
> > > +56   n32     fork                            sys_fork
> > >   57  n32     execve                          compat_sys_execve
> > >   58  n32     exit                            sys_exit
> > >   59  n32     wait4                           compat_sys_wait4
> > > @@ -207,7 +207,7 @@
> > >   196 n32     sched_getaffinity               compat_sys_sched_getaffinity
> > >   197 n32     cacheflush                      sys_cacheflush
> > >   198 n32     cachectl                        sys_cachectl
> > > -199  n32     sysmips                         __sys_sysmips
> > > +199  n32     sysmips                         sys_sysmips
> > >   200 n32     io_setup                        compat_sys_io_setup
> > >   201 n32     io_destroy                      sys_io_destroy
> > >   202 n32     io_getevents                    sys_io_getevents_time32
> > > @@ -373,7 +373,7 @@
> > >   432 n32     fsmount                         sys_fsmount
> > >   433 n32     fspick                          sys_fspick
> > >   434 n32     pidfd_open                      sys_pidfd_open
> > > -435  n32     clone3                          __sys_clone3
> > > +435  n32     clone3                          sys_clone3
> > >   436 n32     close_range                     sys_close_range
> > >   437 n32     openat2                         sys_openat2
> > >   438 n32     pidfd_getfd                     sys_pidfd_getfd
> > > diff --git a/arch/mips/kernel/syscalls/syscall_n64.tbl b/arch/mips/kernel/syscalls/syscall_n64.tbl
> > > index 1ca7bc337932..edec3e82d67a 100644
> > > --- a/arch/mips/kernel/syscalls/syscall_n64.tbl
> > > +++ b/arch/mips/kernel/syscalls/syscall_n64.tbl
> > > @@ -62,8 +62,8 @@
> > >   52  n64     socketpair                      sys_socketpair
> > >   53  n64     setsockopt                      sys_setsockopt
> > >   54  n64     getsockopt                      sys_getsockopt
> > > -55   n64     clone                           __sys_clone
> > > -56   n64     fork                            __sys_fork
> > > +55   n64     clone                           sys_clone
> > > +56   n64     fork                            sys_fork
> > >   57  n64     execve                          sys_execve
> > >   58  n64     exit                            sys_exit
> > >   59  n64     wait4                           sys_wait4
> > > @@ -207,7 +207,7 @@
> > >   196 n64     sched_getaffinity               sys_sched_getaffinity
> > >   197 n64     cacheflush                      sys_cacheflush
> > >   198 n64     cachectl                        sys_cachectl
> > > -199  n64     sysmips                         __sys_sysmips
> > > +199  n64     sysmips                         sys_sysmips
> > >   200 n64     io_setup                        sys_io_setup
> > >   201 n64     io_destroy                      sys_io_destroy
> > >   202 n64     io_getevents                    sys_io_getevents
> > > @@ -349,7 +349,7 @@
> > >   432 n64     fsmount                         sys_fsmount
> > >   433 n64     fspick                          sys_fspick
> > >   434 n64     pidfd_open                      sys_pidfd_open
> > > -435  n64     clone3                          __sys_clone3
> > > +435  n64     clone3                          sys_clone3
> > >   436 n64     close_range                     sys_close_range
> > >   437 n64     openat2                         sys_openat2
> > >   438 n64     pidfd_getfd                     sys_pidfd_getfd
> > > diff --git a/arch/mips/kernel/syscalls/syscall_o32.tbl b/arch/mips/kernel/syscalls/syscall_o32.tbl
> > > index a61c35edaa74..89a1f267da6a 100644
> > > --- a/arch/mips/kernel/syscalls/syscall_o32.tbl
> > > +++ b/arch/mips/kernel/syscalls/syscall_o32.tbl
> > > @@ -9,7 +9,7 @@
> > >   #
> > >   0   o32     syscall                         sys_syscall                     sys32_syscall
> > >   1   o32     exit                            sys_exit
> > > -2    o32     fork                            __sys_fork
> > > +2    o32     fork                            sys_fork
> > >   3   o32     read                            sys_read
> > >   4   o32     write                           sys_write
> > >   5   o32     open                            sys_open                        compat_sys_open
> > > @@ -131,7 +131,7 @@
> > >   117 o32     ipc                             sys_ipc                         compat_sys_ipc
> > >   118 o32     fsync                           sys_fsync
> > >   119 o32     sigreturn                       sys_sigreturn                   sys32_sigreturn
> > > -120  o32     clone                           __sys_clone
> > > +120  o32     clone                           sys_clone
> > >   121 o32     setdomainname                   sys_setdomainname
> > >   122 o32     uname                           sys_newuname
> > >   123 o32     modify_ldt                      sys_ni_syscall
> > > @@ -160,7 +160,7 @@
> > >   146 o32     writev                          sys_writev
> > >   147 o32     cacheflush                      sys_cacheflush
> > >   148 o32     cachectl                        sys_cachectl
> > > -149  o32     sysmips                         __sys_sysmips
> > > +149  o32     sysmips                         sys_sysmips
> > >   150 o32     unused150                       sys_ni_syscall
> > >   151 o32     getsid                          sys_getsid
> > >   152 o32     fdatasync                       sys_fdatasync
> > > @@ -422,7 +422,7 @@
> > >   432 o32     fsmount                         sys_fsmount
> > >   433 o32     fspick                          sys_fspick
> > >   434 o32     pidfd_open                      sys_pidfd_open
> > > -435  o32     clone3                          __sys_clone3
> > > +435  o32     clone3                          sys_clone3
> > >   436 o32     close_range                     sys_close_range
> > >   437 o32     openat2                         sys_openat2
> > >   438 o32     pidfd_getfd                     sys_pidfd_getfd

^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: [PATCH 2/2] mips: convert irq to generic entry
  2021-09-07  6:16 ` [PATCH 2/2] mips: convert irq " FreeFlyingSheep
@ 2021-09-08  7:17   ` Huacai Chen
  0 siblings, 0 replies; 15+ messages in thread
From: Huacai Chen @ 2021-09-08  7:17 UTC (permalink / raw)
  To: FreeFlyingSheep
  Cc: Thomas Bogendoerfer, Thomas Gleixner, Peter Zijlstra,
	Andy Lutomirski, Arnd Bergmann, Feiyang Chen, open list:MIPS,
	linux-arch, Jiaxun Yang, Yanteng Si

Reviewed-by: Huacai Chen <chenhuacai@kernel.org>

On Tue, Sep 7, 2021 at 2:17 PM FreeFlyingSheep
<chris.chenfeiyang@gmail.com> wrote:
>
> From: Feiyang Chen <chenfeiyang@loongson.cn>
>
> Convert mips irq to use the generic entry infrastructure from
> kernel/entry/*.
>
> When entering the handler functions written in C, there are three
> status: STI, CLI and KMODE. Now use CLI for all handler functions,
> since interrupts must be disabled before calling irqentry_enter().
>
> - For handler functions who originally used STI, enable interrupts
> after calling irqentry_enter().
>
> - For handler functions who originally used KMODE, enable interrupts
> after calling irqentry_enter() only if they are enabled in the parent
> context.
>
> - If CONFIG_HARDWARE_WATCHPOINTS is defined, interrupts will be enabled
> after the watch registers are read. Only enable interrupts manually in
> do_watch() if it is not defined.
>
> The IRQ stack is disabled temporarily because it is too complex to
> collaborate with the generic code (this will be improved by later
> patches).
>
> Signed-off-by: Feiyang Chen <chenfeiyang@loongson.cn>
> Signed-off-by: Yanteng Si <siyanteng@loongson.cn>
> ---
>  arch/mips/include/asm/irqflags.h   |  42 ------
>  arch/mips/include/asm/stackframe.h |   8 ++
>  arch/mips/kernel/entry.S           |  82 ------------
>  arch/mips/kernel/genex.S           | 148 ++++-----------------
>  arch/mips/kernel/head.S            |   1 -
>  arch/mips/kernel/r4k-bugs64.c      |  14 +-
>  arch/mips/kernel/scall.S           |   7 +-
>  arch/mips/kernel/signal.c          |  26 ----
>  arch/mips/kernel/traps.c           | 202 ++++++++++++++++++++---------
>  arch/mips/kernel/unaligned.c       |  19 +--
>  arch/mips/mm/c-octeon.c            |  15 +++
>  arch/mips/mm/cex-oct.S             |   8 +-
>  arch/mips/mm/fault.c               |  12 +-
>  arch/mips/mm/tlbex-fault.S         |   7 +-
>  14 files changed, 230 insertions(+), 361 deletions(-)
>
> diff --git a/arch/mips/include/asm/irqflags.h b/arch/mips/include/asm/irqflags.h
> index f5b8300f4573..ee7519b0d23f 100644
> --- a/arch/mips/include/asm/irqflags.h
> +++ b/arch/mips/include/asm/irqflags.h
> @@ -11,8 +11,6 @@
>  #ifndef _ASM_IRQFLAGS_H
>  #define _ASM_IRQFLAGS_H
>
> -#ifndef __ASSEMBLY__
> -
>  #include <linux/compiler.h>
>  #include <linux/stringify.h>
>  #include <asm/compiler.h>
> @@ -142,44 +140,4 @@ static inline int arch_irqs_disabled(void)
>         return arch_irqs_disabled_flags(arch_local_save_flags());
>  }
>
> -#endif /* #ifndef __ASSEMBLY__ */
> -
> -/*
> - * Do the CPU's IRQ-state tracing from assembly code.
> - */
> -#ifdef CONFIG_TRACE_IRQFLAGS
> -/* Reload some registers clobbered by trace_hardirqs_on */
> -#ifdef CONFIG_64BIT
> -# define TRACE_IRQS_RELOAD_REGS                                                \
> -       LONG_L  $11, PT_R11(sp);                                        \
> -       LONG_L  $10, PT_R10(sp);                                        \
> -       LONG_L  $9, PT_R9(sp);                                          \
> -       LONG_L  $8, PT_R8(sp);                                          \
> -       LONG_L  $7, PT_R7(sp);                                          \
> -       LONG_L  $6, PT_R6(sp);                                          \
> -       LONG_L  $5, PT_R5(sp);                                          \
> -       LONG_L  $4, PT_R4(sp);                                          \
> -       LONG_L  $2, PT_R2(sp)
> -#else
> -# define TRACE_IRQS_RELOAD_REGS                                                \
> -       LONG_L  $7, PT_R7(sp);                                          \
> -       LONG_L  $6, PT_R6(sp);                                          \
> -       LONG_L  $5, PT_R5(sp);                                          \
> -       LONG_L  $4, PT_R4(sp);                                          \
> -       LONG_L  $2, PT_R2(sp)
> -#endif
> -# define TRACE_IRQS_ON                                                 \
> -       CLI;    /* make sure trace_hardirqs_on() is called in kernel level */ \
> -       jal     trace_hardirqs_on
> -# define TRACE_IRQS_ON_RELOAD                                          \
> -       TRACE_IRQS_ON;                                                  \
> -       TRACE_IRQS_RELOAD_REGS
> -# define TRACE_IRQS_OFF                                                        \
> -       jal     trace_hardirqs_off
> -#else
> -# define TRACE_IRQS_ON
> -# define TRACE_IRQS_ON_RELOAD
> -# define TRACE_IRQS_OFF
> -#endif
> -
>  #endif /* _ASM_IRQFLAGS_H */
> diff --git a/arch/mips/include/asm/stackframe.h b/arch/mips/include/asm/stackframe.h
> index aa430a6c68b2..8bc74d7950fb 100644
> --- a/arch/mips/include/asm/stackframe.h
> +++ b/arch/mips/include/asm/stackframe.h
> @@ -444,6 +444,14 @@
>                 RESTORE_SP \docfi
>                 .endm
>
> +               .macro  RESTORE_ALL_AND_RET docfi=0
> +               RESTORE_TEMP \docfi
> +               RESTORE_STATIC \docfi
> +               RESTORE_AT \docfi
> +               RESTORE_SOME \docfi
> +               RESTORE_SP_AND_RET \docfi
> +               .endm
> +
>  /*
>   * Move to kernel mode and disable interrupts.
>   * Set cp0 enable bit as sign that we're running on the kernel stack
> diff --git a/arch/mips/kernel/entry.S b/arch/mips/kernel/entry.S
> index 1a2aec9dab1b..c9148831d820 100644
> --- a/arch/mips/kernel/entry.S
> +++ b/arch/mips/kernel/entry.S
> @@ -11,7 +11,6 @@
>  #include <asm/asm.h>
>  #include <asm/asmmacro.h>
>  #include <asm/compiler.h>
> -#include <asm/irqflags.h>
>  #include <asm/regdef.h>
>  #include <asm/mipsregs.h>
>  #include <asm/stackframe.h>
> @@ -19,55 +18,8 @@
>  #include <asm/thread_info.h>
>  #include <asm/war.h>
>
> -#ifndef CONFIG_PREEMPTION
> -#define resume_kernel  restore_all
> -#else
> -#define __ret_from_irq ret_from_exception
> -#endif
> -
>         .text
>         .align  5
> -#ifndef CONFIG_PREEMPTION
> -FEXPORT(ret_from_exception)
> -       local_irq_disable                       # preempt stop
> -       b       __ret_from_irq
> -#endif
> -FEXPORT(ret_from_irq)
> -       LONG_S  s0, TI_REGS($28)
> -FEXPORT(__ret_from_irq)
> -/*
> - * We can be coming here from a syscall done in the kernel space,
> - * e.g. a failed kernel_execve().
> - */
> -resume_userspace_check:
> -       LONG_L  t0, PT_STATUS(sp)               # returning to kernel mode?
> -       andi    t0, t0, KU_USER
> -       beqz    t0, resume_kernel
> -
> -resume_userspace:
> -       local_irq_disable               # make sure we dont miss an
> -                                       # interrupt setting need_resched
> -                                       # between sampling and return
> -       LONG_L  a2, TI_FLAGS($28)       # current->work
> -       andi    t0, a2, _TIF_WORK_MASK  # (ignoring syscall_trace)
> -       bnez    t0, work_pending
> -       j       restore_all
> -
> -#ifdef CONFIG_PREEMPTION
> -resume_kernel:
> -       local_irq_disable
> -       lw      t0, TI_PRE_COUNT($28)
> -       bnez    t0, restore_all
> -       LONG_L  t0, TI_FLAGS($28)
> -       andi    t1, t0, _TIF_NEED_RESCHED
> -       beqz    t1, restore_all
> -       LONG_L  t0, PT_STATUS(sp)               # Interrupts off?
> -       andi    t0, 1
> -       beqz    t0, restore_all
> -       PTR_LA  ra, restore_all
> -       j       preempt_schedule_irq
> -#endif
> -
>  FEXPORT(ret_from_kernel_thread)
>         jal     schedule_tail           # a0 = struct task_struct *prev
>         move    a0, s1
> @@ -92,40 +44,6 @@ FEXPORT(ret_from_fork)
>         RESTORE_SP_AND_RET
>         .set    at
>
> -restore_all:                           # restore full frame
> -       .set    noat
> -       RESTORE_TEMP
> -       RESTORE_AT
> -       RESTORE_STATIC
> -restore_partial:                       # restore partial frame
> -       RESTORE_SOME
> -       RESTORE_SP_AND_RET
> -       .set    at
> -
> -work_pending:
> -       andi    t0, a2, _TIF_NEED_RESCHED # a2 is preloaded with TI_FLAGS
> -       beqz    t0, work_notifysig
> -work_resched:
> -       TRACE_IRQS_OFF
> -       jal     schedule
> -
> -       local_irq_disable               # make sure need_resched and
> -                                       # signals dont change between
> -                                       # sampling and return
> -       LONG_L  a2, TI_FLAGS($28)
> -       andi    t0, a2, _TIF_WORK_MASK  # is there any work to be done
> -                                       # other than syscall tracing?
> -       beqz    t0, restore_all
> -       andi    t0, a2, _TIF_NEED_RESCHED
> -       bnez    t0, work_resched
> -
> -work_notifysig:                                # deal with pending signals and
> -                                       # notify-resume requests
> -       move    a0, sp
> -       li      a1, 0
> -       jal     do_notify_resume        # a2 already loaded
> -       j       resume_userspace_check
> -
>  #if defined(CONFIG_CPU_MIPSR2) || defined(CONFIG_CPU_MIPSR5) || \
>      defined(CONFIG_CPU_MIPSR6) || defined(CONFIG_MIPS_MT)
>
> diff --git a/arch/mips/kernel/genex.S b/arch/mips/kernel/genex.S
> index 743d75927b71..60e288d307ff 100644
> --- a/arch/mips/kernel/genex.S
> +++ b/arch/mips/kernel/genex.S
> @@ -13,7 +13,6 @@
>  #include <asm/asm.h>
>  #include <asm/asmmacro.h>
>  #include <asm/cacheops.h>
> -#include <asm/irqflags.h>
>  #include <asm/regdef.h>
>  #include <asm/fpregdef.h>
>  #include <asm/mipsregs.h>
> @@ -182,53 +181,16 @@ NESTED(handle_int, PT_SIZE, sp)
>  #endif
>         SAVE_ALL docfi=1
>         CLI
> -       TRACE_IRQS_OFF
>
> -       LONG_L  s0, TI_REGS($28)
> -       LONG_S  sp, TI_REGS($28)
> -
> -       /*
> -        * SAVE_ALL ensures we are using a valid kernel stack for the thread.
> -        * Check if we are already using the IRQ stack.
> -        */
> -       move    s1, sp # Preserve the sp
> -
> -       /* Get IRQ stack for this CPU */
> -       ASM_CPUID_MFC0  k0, ASM_SMP_CPUID_REG
> -#if defined(CONFIG_32BIT) || defined(KBUILD_64BIT_SYM32)
> -       lui     k1, %hi(irq_stack)
> -#else
> -       lui     k1, %highest(irq_stack)
> -       daddiu  k1, %higher(irq_stack)
> -       dsll    k1, 16
> -       daddiu  k1, %hi(irq_stack)
> -       dsll    k1, 16
> -#endif
> -       LONG_SRL        k0, SMP_CPUID_PTRSHIFT
> -       LONG_ADDU       k1, k0
> -       LONG_L  t0, %lo(irq_stack)(k1)
> -
> -       # Check if already on IRQ stack
> -       PTR_LI  t1, ~(_THREAD_SIZE-1)
> -       and     t1, t1, sp
> -       beq     t0, t1, 2f
> -
> -       /* Switch to IRQ stack */
> -       li      t1, _IRQ_STACK_START
> -       PTR_ADD sp, t0, t1
> -
> -       /* Save task's sp on IRQ stack so that unwinding can follow it */
> -       LONG_S  s1, 0(sp)
> -2:
> -       jal     plat_irq_dispatch
> -
> -       /* Restore sp */
> -       move    sp, s1
> -
> -       j       ret_from_irq
> +       move    a0, sp
> +       jal     do_int
>  #ifdef CONFIG_CPU_MICROMIPS
>         nop
>  #endif
> +
> +       .set    noat
> +       RESTORE_ALL_AND_RET
> +       .set    at
>         END(handle_int)
>
>         __INIT
> @@ -290,54 +252,12 @@ NESTED(except_vec_vi_handler, 0, sp)
>         SAVE_TEMP
>         SAVE_STATIC
>         CLI
> -#ifdef CONFIG_TRACE_IRQFLAGS
> -       move    s0, v0
> -       TRACE_IRQS_OFF
> -       move    v0, s0
> -#endif
> -
> -       LONG_L  s0, TI_REGS($28)
> -       LONG_S  sp, TI_REGS($28)
>
> -       /*
> -        * SAVE_ALL ensures we are using a valid kernel stack for the thread.
> -        * Check if we are already using the IRQ stack.
> -        */
> -       move    s1, sp # Preserve the sp
> -
> -       /* Get IRQ stack for this CPU */
> -       ASM_CPUID_MFC0  k0, ASM_SMP_CPUID_REG
> -#if defined(CONFIG_32BIT) || defined(KBUILD_64BIT_SYM32)
> -       lui     k1, %hi(irq_stack)
> -#else
> -       lui     k1, %highest(irq_stack)
> -       daddiu  k1, %higher(irq_stack)
> -       dsll    k1, 16
> -       daddiu  k1, %hi(irq_stack)
> -       dsll    k1, 16
> -#endif
> -       LONG_SRL        k0, SMP_CPUID_PTRSHIFT
> -       LONG_ADDU       k1, k0
> -       LONG_L  t0, %lo(irq_stack)(k1)
> -
> -       # Check if already on IRQ stack
> -       PTR_LI  t1, ~(_THREAD_SIZE-1)
> -       and     t1, t1, sp
> -       beq     t0, t1, 2f
> -
> -       /* Switch to IRQ stack */
> -       li      t1, _IRQ_STACK_START
> -       PTR_ADD sp, t0, t1
> -
> -       /* Save task's sp on IRQ stack so that unwinding can follow it */
> -       LONG_S  s1, 0(sp)
> -2:
> -       jalr    v0
> -
> -       /* Restore sp */
> -       move    sp, s1
> +       move    a0, sp
> +       move    a1, v0
> +       jal     do_vi
>
> -       j       ret_from_irq
> +       RESTORE_ALL_AND_RET
>         END(except_vec_vi_handler)
>
>  /*
> @@ -462,22 +382,12 @@ NESTED(nmi_handler, PT_SIZE, sp)
>         .set    pop
>         END(nmi_handler)
>
> -       .macro  __build_clear_none
> -       .endm
> -
> -       .macro  __build_clear_sti
> -       TRACE_IRQS_ON
> -       STI
> -       .endm
> -
>         .macro  __build_clear_cli
>         CLI
> -       TRACE_IRQS_OFF
>         .endm
>
>         .macro  __build_clear_fpe
>         CLI
> -       TRACE_IRQS_OFF
>         .set    push
>         /* gas fails to assemble cfc1 for some archs (octeon).*/ \
>         .set    mips1
> @@ -488,14 +398,13 @@ NESTED(nmi_handler, PT_SIZE, sp)
>
>         .macro  __build_clear_msa_fpe
>         CLI
> -       TRACE_IRQS_OFF
>         _cfcmsa a1, MSA_CSR
>         .endm
>
>         .macro  __build_clear_ade
>         MFC0    t0, CP0_BADVADDR
>         PTR_S   t0, PT_BVADDR(sp)
> -       KMODE
> +       CLI
>         .endm
>
>         .macro __build_clear_gsexc
> @@ -507,8 +416,7 @@ NESTED(nmi_handler, PT_SIZE, sp)
>         .set    mips32
>         mfc0    a1, CP0_DIAGNOSTIC1
>         .set    pop
> -       TRACE_IRQS_ON
> -       STI
> +       CLI
>         .endm
>
>         .macro  __BUILD_silent exception
> @@ -547,7 +455,7 @@ NESTED(nmi_handler, PT_SIZE, sp)
>         __BUILD_\verbose \exception
>         move    a0, sp
>         jal     do_\handler
> -       j       ret_from_exception
> +       RESTORE_ALL_AND_RET
>         END(handle_\exception)
>         .endm
>
> @@ -559,32 +467,28 @@ NESTED(nmi_handler, PT_SIZE, sp)
>         BUILD_HANDLER ades ade ade silent               /* #5  */
>         BUILD_HANDLER ibe be cli silent                 /* #6  */
>         BUILD_HANDLER dbe be cli silent                 /* #7  */
> -       BUILD_HANDLER bp bp sti silent                  /* #9  */
> -       BUILD_HANDLER ri ri sti silent                  /* #10 */
> -       BUILD_HANDLER cpu cpu sti silent                /* #11 */
> -       BUILD_HANDLER ov ov sti silent                  /* #12 */
> -       BUILD_HANDLER tr tr sti silent                  /* #13 */
> +       BUILD_HANDLER bp bp cli silent                  /* #9  */
> +       BUILD_HANDLER ri ri cli silent                  /* #10 */
> +       BUILD_HANDLER cpu cpu cli silent                /* #11 */
> +       BUILD_HANDLER ov ov cli silent                  /* #12 */
> +       BUILD_HANDLER tr tr cli silent                  /* #13 */
>         BUILD_HANDLER msa_fpe msa_fpe msa_fpe silent    /* #14 */
>  #ifdef CONFIG_MIPS_FP_SUPPORT
>         BUILD_HANDLER fpe fpe fpe silent                /* #15 */
>  #endif
> -       BUILD_HANDLER ftlb ftlb none silent             /* #16 */
> +       BUILD_HANDLER ftlb ftlb cli silent              /* #16 */
>         BUILD_HANDLER gsexc gsexc gsexc silent          /* #16 */
> -       BUILD_HANDLER msa msa sti silent                /* #21 */
> -       BUILD_HANDLER mdmx mdmx sti silent              /* #22 */
> +       BUILD_HANDLER msa msa cli silent                /* #21 */
> +       BUILD_HANDLER mdmx mdmx cli silent              /* #22 */
>  #ifdef CONFIG_HARDWARE_WATCHPOINTS
> -       /*
> -        * For watch, interrupts will be enabled after the watch
> -        * registers are read.
> -        */
>         BUILD_HANDLER watch watch cli silent            /* #23 */
>  #else
> -       BUILD_HANDLER watch watch sti verbose           /* #23 */
> +       BUILD_HANDLER watch watch cli verbose           /* #23 */
>  #endif
>         BUILD_HANDLER mcheck mcheck cli verbose         /* #24 */
> -       BUILD_HANDLER mt mt sti silent                  /* #25 */
> -       BUILD_HANDLER dsp dsp sti silent                /* #26 */
> -       BUILD_HANDLER reserved reserved sti verbose     /* others */
> +       BUILD_HANDLER mt mt cli silent                  /* #25 */
> +       BUILD_HANDLER dsp dsp cli silent                /* #26 */
> +       BUILD_HANDLER reserved reserved cli verbose     /* others */
>
>         .align  5
>         LEAF(handle_ri_rdhwr_tlbp)
> @@ -678,5 +582,5 @@ isrdhwr:
>
>         __INIT
>
> -       BUILD_HANDLER  daddi_ov daddi_ov none silent    /* #12 */
> +       BUILD_HANDLER  daddi_ov daddi_ov cli silent     /* #12 */
>  #endif
> diff --git a/arch/mips/kernel/head.S b/arch/mips/kernel/head.S
> index b825ed4476c7..5f028dbd5961 100644
> --- a/arch/mips/kernel/head.S
> +++ b/arch/mips/kernel/head.S
> @@ -19,7 +19,6 @@
>  #include <asm/addrspace.h>
>  #include <asm/asm.h>
>  #include <asm/asmmacro.h>
> -#include <asm/irqflags.h>
>  #include <asm/regdef.h>
>  #include <asm/mipsregs.h>
>  #include <asm/stackframe.h>
> diff --git a/arch/mips/kernel/r4k-bugs64.c b/arch/mips/kernel/r4k-bugs64.c
> index 35729c9e6cfa..0384b649877c 100644
> --- a/arch/mips/kernel/r4k-bugs64.c
> +++ b/arch/mips/kernel/r4k-bugs64.c
> @@ -3,6 +3,7 @@
>   * Copyright (C) 2003, 2004, 2007  Maciej W. Rozycki
>   */
>  #include <linux/context_tracking.h>
> +#include <linux/entry-common.h>
>  #include <linux/init.h>
>  #include <linux/kernel.h>
>  #include <linux/ptrace.h>
> @@ -168,14 +169,19 @@ static __always_inline __init void check_mult_sh(void)
>
>  static volatile int daddi_ov;
>
> -asmlinkage void __init do_daddi_ov(struct pt_regs *regs)
> +asmlinkage void noinstr __init do_daddi_ov(struct pt_regs *regs)
>  {
> -       enum ctx_state prev_state;
> +       irqentry_state_t state = irqentry_enter(regs);
> +
> +       /* Enable interrupt if enabled in parent context */
> +       if (likely(!regs_irqs_disabled(regs)))
> +               local_irq_enable();
>
> -       prev_state = exception_enter();
>         daddi_ov = 1;
>         regs->cp0_epc += 4;
> -       exception_exit(prev_state);
> +
> +       local_irq_disable();
> +       irqentry_exit(regs, state);
>  }
>
>  static __init void check_daddi(void)
> diff --git a/arch/mips/kernel/scall.S b/arch/mips/kernel/scall.S
> index 7b35969151de..3bd955ce5462 100644
> --- a/arch/mips/kernel/scall.S
> +++ b/arch/mips/kernel/scall.S
> @@ -9,7 +9,6 @@
>  #include <linux/errno.h>
>  #include <asm/asm.h>
>  #include <asm/asmmacro.h>
> -#include <asm/irqflags.h>
>  #include <asm/mipsregs.h>
>  #include <asm/regdef.h>
>  #include <asm/stackframe.h>
> @@ -31,11 +30,7 @@ NESTED(handle_sys, PT_SIZE, sp)
>         jal     do_syscall
>
>         .set    noat
> -       RESTORE_TEMP
> -       RESTORE_AT
> -       RESTORE_STATIC
> -       RESTORE_SOME
> -       RESTORE_SP_AND_RET
> +       RESTORE_ALL_AND_RET
>         .set    at
>         END(handle_sys)
>
> diff --git a/arch/mips/kernel/signal.c b/arch/mips/kernel/signal.c
> index 1ec6a0cf1163..dbcfbaf03558 100644
> --- a/arch/mips/kernel/signal.c
> +++ b/arch/mips/kernel/signal.c
> @@ -875,32 +875,6 @@ void arch_do_signal_or_restart(struct pt_regs *regs, bool has_signal)
>         restore_saved_sigmask();
>  }
>
> -/*
> - * notification of userspace execution resumption
> - * - triggered by the TIF_WORK_MASK flags
> - */
> -asmlinkage void do_notify_resume(struct pt_regs *regs, void *unused,
> -       __u32 thread_info_flags)
> -{
> -       local_irq_enable();
> -
> -       user_exit();
> -
> -       if (thread_info_flags & _TIF_UPROBE)
> -               uprobe_notify_resume(regs);
> -
> -       /* deal with pending signal delivery */
> -       if (thread_info_flags & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL))
> -               arch_do_signal_or_restart(regs, thread_info_flags & _TIF_SIGPENDING);
> -
> -       if (thread_info_flags & _TIF_NOTIFY_RESUME) {
> -               tracehook_notify_resume(regs);
> -               rseq_handle_notify_resume(NULL, regs);
> -       }
> -
> -       user_enter();
> -}
> -
>  #if defined(CONFIG_SMP) && defined(CONFIG_MIPS_FP_SUPPORT)
>  static int smp_save_fp_context(void __user *sc)
>  {
> diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
> index 6f07362de5ce..69290e67dd68 100644
> --- a/arch/mips/kernel/traps.c
> +++ b/arch/mips/kernel/traps.c
> @@ -17,6 +17,7 @@
>  #include <linux/compiler.h>
>  #include <linux/context_tracking.h>
>  #include <linux/cpu_pm.h>
> +#include <linux/entry-common.h>
>  #include <linux/kexec.h>
>  #include <linux/init.h>
>  #include <linux/kernel.h>
> @@ -438,15 +439,14 @@ static const struct exception_table_entry *search_dbe_tables(unsigned long addr)
>         return e;
>  }
>
> -asmlinkage void do_be(struct pt_regs *regs)
> +asmlinkage void noinstr do_be(struct pt_regs *regs)
>  {
> +       irqentry_state_t state = irqentry_enter(regs);
>         const int field = 2 * sizeof(unsigned long);
>         const struct exception_table_entry *fixup = NULL;
>         int data = regs->cp0_cause & 4;
>         int action = MIPS_BE_FATAL;
> -       enum ctx_state prev_state;
>
> -       prev_state = exception_enter();
>         /* XXX For now.  Fixme, this searches the wrong table ...  */
>         if (data && !user_mode(regs))
>                 fixup = search_dbe_tables(exception_epc(regs));
> @@ -486,7 +486,7 @@ asmlinkage void do_be(struct pt_regs *regs)
>         force_sig(SIGBUS);
>
>  out:
> -       exception_exit(prev_state);
> +       irqentry_exit(regs, state);
>  }
>
>  /*
> @@ -743,15 +743,18 @@ static int simulate_loongson3_cpucfg(struct pt_regs *regs,
>  }
>  #endif /* CONFIG_CPU_LOONGSON3_CPUCFG_EMULATION */
>
> -asmlinkage void do_ov(struct pt_regs *regs)
> +asmlinkage void noinstr do_ov(struct pt_regs *regs)
>  {
> -       enum ctx_state prev_state;
> +       irqentry_state_t state = irqentry_enter(regs);
> +
> +       local_irq_enable();
>
> -       prev_state = exception_enter();
>         die_if_kernel("Integer overflow", regs);
>
>         force_sig_fault(SIGFPE, FPE_INTOVF, (void __user *)regs->cp0_epc);
> -       exception_exit(prev_state);
> +
> +       local_irq_disable();
> +       irqentry_exit(regs, state);
>  }
>
>  #ifdef CONFIG_MIPS_FP_SUPPORT
> @@ -865,13 +868,12 @@ static int simulate_fp(struct pt_regs *regs, unsigned int opcode,
>  /*
>   * XXX Delayed fp exceptions when doing a lazy ctx switch XXX
>   */
> -asmlinkage void do_fpe(struct pt_regs *regs, unsigned long fcr31)
> +asmlinkage void noinstr do_fpe(struct pt_regs *regs, unsigned long fcr31)
>  {
> -       enum ctx_state prev_state;
> +       irqentry_state_t state = irqentry_enter(regs);
>         void __user *fault_addr;
>         int sig;
>
> -       prev_state = exception_enter();
>         if (notify_die(DIE_FP, "FP exception", regs, 0, current->thread.trap_nr,
>                        SIGFPE) == NOTIFY_STOP)
>                 goto out;
> @@ -916,7 +918,8 @@ asmlinkage void do_fpe(struct pt_regs *regs, unsigned long fcr31)
>         process_fpemu_return(sig, fault_addr, fcr31);
>
>  out:
> -       exception_exit(prev_state);
> +       local_irq_disable();
> +       irqentry_exit(regs, state);
>  }
>
>  /*
> @@ -1018,14 +1021,16 @@ void do_trap_or_bp(struct pt_regs *regs, unsigned int code, int si_code,
>         }
>  }
>
> -asmlinkage void do_bp(struct pt_regs *regs)
> +asmlinkage void noinstr do_bp(struct pt_regs *regs)
>  {
> -       unsigned long epc = msk_isa16_mode(exception_epc(regs));
> -       unsigned int opcode, bcode;
> -       enum ctx_state prev_state;
> +       irqentry_state_t state = irqentry_enter(regs);
>         bool user = user_mode(regs);
> +       unsigned int opcode, bcode;
> +       unsigned long epc;
> +
> +       local_irq_enable();
>
> -       prev_state = exception_enter();
> +       epc = msk_isa16_mode(exception_epc(regs));
>         current->thread.trap_nr = (regs->cp0_cause >> 2) & 0x1f;
>         if (get_isa16_mode(regs->cp0_epc)) {
>                 u16 instr[2];
> @@ -1097,7 +1102,8 @@ asmlinkage void do_bp(struct pt_regs *regs)
>         do_trap_or_bp(regs, bcode, TRAP_BRKPT, "Break");
>
>  out:
> -       exception_exit(prev_state);
> +       local_irq_disable();
> +       irqentry_exit(regs, state);
>         return;
>
>  out_sigsegv:
> @@ -1105,15 +1111,17 @@ asmlinkage void do_bp(struct pt_regs *regs)
>         goto out;
>  }
>
> -asmlinkage void do_tr(struct pt_regs *regs)
> +asmlinkage void noinstr do_tr(struct pt_regs *regs)
>  {
> +       irqentry_state_t state = irqentry_enter(regs);
> +       bool user = user_mode(regs);
>         u32 opcode, tcode = 0;
> -       enum ctx_state prev_state;
> +       unsigned long epc;
>         u16 instr[2];
> -       bool user = user_mode(regs);
> -       unsigned long epc = msk_isa16_mode(exception_epc(regs));
>
> -       prev_state = exception_enter();
> +       local_irq_enable();
> +
> +       epc = msk_isa16_mode(exception_epc(regs));
>         current->thread.trap_nr = (regs->cp0_cause >> 2) & 0x1f;
>         if (get_isa16_mode(regs->cp0_epc)) {
>                 if (__get_inst16(&instr[0], (u16 *)(epc + 0), user) ||
> @@ -1134,7 +1142,8 @@ asmlinkage void do_tr(struct pt_regs *regs)
>         do_trap_or_bp(regs, tcode, 0, "Trap");
>
>  out:
> -       exception_exit(prev_state);
> +       local_irq_disable();
> +       irqentry_exit(regs, state);
>         return;
>
>  out_sigsegv:
> @@ -1142,15 +1151,19 @@ asmlinkage void do_tr(struct pt_regs *regs)
>         goto out;
>  }
>
> -asmlinkage void do_ri(struct pt_regs *regs)
> +asmlinkage void noinstr do_ri(struct pt_regs *regs)
>  {
> -       unsigned int __user *epc = (unsigned int __user *)exception_epc(regs);
> +       irqentry_state_t state = irqentry_enter(regs);
>         unsigned long old_epc = regs->cp0_epc;
>         unsigned long old31 = regs->regs[31];
> -       enum ctx_state prev_state;
> +       unsigned int __user *epc;
>         unsigned int opcode = 0;
>         int status = -1;
>
> +       local_irq_enable();
> +
> +       epc = (unsigned int __user *)exception_epc(regs);
> +
>         /*
>          * Avoid any kernel code. Just emulate the R2 instruction
>          * as quickly as possible.
> @@ -1177,7 +1190,6 @@ asmlinkage void do_ri(struct pt_regs *regs)
>
>  no_r2_instr:
>
> -       prev_state = exception_enter();
>         current->thread.trap_nr = (regs->cp0_cause >> 2) & 0x1f;
>
>         if (notify_die(DIE_RI, "RI Fault", regs, 0, current->thread.trap_nr,
> @@ -1233,7 +1245,8 @@ asmlinkage void do_ri(struct pt_regs *regs)
>         }
>
>  out:
> -       exception_exit(prev_state);
> +       local_irq_disable();
> +       irqentry_exit(regs, state);
>  }
>
>  /*
> @@ -1393,16 +1406,17 @@ static int enable_restore_fp_context(int msa)
>
>  #endif /* CONFIG_MIPS_FP_SUPPORT */
>
> -asmlinkage void do_cpu(struct pt_regs *regs)
> +asmlinkage void noinstr do_cpu(struct pt_regs *regs)
>  {
> -       enum ctx_state prev_state;
> +       irqentry_state_t state = irqentry_enter(regs);
>         unsigned int __user *epc;
>         unsigned long old_epc, old31;
>         unsigned int opcode;
>         unsigned int cpid;
>         int status;
>
> -       prev_state = exception_enter();
> +       local_irq_enable();
> +
>         cpid = (regs->cp0_cause >> CAUSEB_CE) & 3;
>
>         if (cpid != 2)
> @@ -1495,14 +1509,14 @@ asmlinkage void do_cpu(struct pt_regs *regs)
>                 break;
>         }
>
> -       exception_exit(prev_state);
> +       local_irq_disable();
> +       irqentry_exit(regs, state);
>  }
>
> -asmlinkage void do_msa_fpe(struct pt_regs *regs, unsigned int msacsr)
> +asmlinkage void noinstr do_msa_fpe(struct pt_regs *regs, unsigned int msacsr)
>  {
> -       enum ctx_state prev_state;
> +       irqentry_state_t state = irqentry_enter(regs);
>
> -       prev_state = exception_enter();
>         current->thread.trap_nr = (regs->cp0_cause >> 2) & 0x1f;
>         if (notify_die(DIE_MSAFP, "MSA FP exception", regs, 0,
>                        current->thread.trap_nr, SIGFPE) == NOTIFY_STOP)
> @@ -1514,16 +1528,18 @@ asmlinkage void do_msa_fpe(struct pt_regs *regs, unsigned int msacsr)
>
>         die_if_kernel("do_msa_fpe invoked from kernel context!", regs);
>         force_sig(SIGFPE);
> +
>  out:
> -       exception_exit(prev_state);
> +       local_irq_disable();
> +       irqentry_exit(regs, state);
>  }
>
> -asmlinkage void do_msa(struct pt_regs *regs)
> +asmlinkage void noinstr do_msa(struct pt_regs *regs)
>  {
> -       enum ctx_state prev_state;
> +       irqentry_state_t state = irqentry_enter(regs);
>         int err;
>
> -       prev_state = exception_enter();
> +       local_irq_enable();
>
>         if (!cpu_has_msa || test_thread_flag(TIF_32BIT_FPREGS)) {
>                 force_sig(SIGILL);
> @@ -1535,27 +1551,39 @@ asmlinkage void do_msa(struct pt_regs *regs)
>         err = enable_restore_fp_context(1);
>         if (err)
>                 force_sig(SIGILL);
> +
>  out:
> -       exception_exit(prev_state);
> +       local_irq_disable();
> +       irqentry_exit(regs, state);
>  }
>
> -asmlinkage void do_mdmx(struct pt_regs *regs)
> +asmlinkage void noinstr do_mdmx(struct pt_regs *regs)
>  {
> -       enum ctx_state prev_state;
> +       irqentry_state_t state = irqentry_enter(regs);
> +
> +       local_irq_enable();
>
> -       prev_state = exception_enter();
>         force_sig(SIGILL);
> -       exception_exit(prev_state);
> +
> +       local_irq_disable();
> +       irqentry_exit(regs, state);
>  }
>
>  /*
>   * Called with interrupts disabled.
>   */
> -asmlinkage void do_watch(struct pt_regs *regs)
> +asmlinkage void noinstr do_watch(struct pt_regs *regs)
>  {
> -       enum ctx_state prev_state;
> +       irqentry_state_t state = irqentry_enter(regs);
> +
> +#ifndef CONFIG_HARDWARE_WATCHPOINTS
> +       /*
> +        * For watch, interrupts will be enabled after the watch
> +        * registers are read.
> +        */
> +       local_irq_enable();
> +#endif
>
> -       prev_state = exception_enter();
>         /*
>          * Clear WP (bit 22) bit of cause register so we don't loop
>          * forever.
> @@ -1575,15 +1603,16 @@ asmlinkage void do_watch(struct pt_regs *regs)
>                 mips_clear_watch_registers();
>                 local_irq_enable();
>         }
> -       exception_exit(prev_state);
> +
> +       local_irq_disable();
> +       irqentry_exit(regs, state);
>  }
>
> -asmlinkage void do_mcheck(struct pt_regs *regs)
> +asmlinkage void noinstr do_mcheck(struct pt_regs *regs)
>  {
> +       irqentry_state_t state = irqentry_enter(regs);
>         int multi_match = regs->cp0_status & ST0_TS;
> -       enum ctx_state prev_state;
>
> -       prev_state = exception_enter();
>         show_regs(regs);
>
>         if (multi_match) {
> @@ -1601,12 +1630,17 @@ asmlinkage void do_mcheck(struct pt_regs *regs)
>         panic("Caught Machine Check exception - %scaused by multiple "
>               "matching entries in the TLB.",
>               (multi_match) ? "" : "not ");
> +
> +       irqentry_exit(regs, state);
>  }
>
> -asmlinkage void do_mt(struct pt_regs *regs)
> +asmlinkage void noinstr do_mt(struct pt_regs *regs)
>  {
> +       irqentry_state_t state = irqentry_enter(regs);
>         int subcode;
>
> +       local_irq_enable();
> +
>         subcode = (read_vpe_c0_vpecontrol() & VPECONTROL_EXCPT)
>                         >> VPECONTROL_EXCPT_SHIFT;
>         switch (subcode) {
> @@ -1636,19 +1670,33 @@ asmlinkage void do_mt(struct pt_regs *regs)
>         die_if_kernel("MIPS MT Thread exception in kernel", regs);
>
>         force_sig(SIGILL);
> +
> +       local_irq_disable();
> +       irqentry_exit(regs, state);
>  }
>
>
> -asmlinkage void do_dsp(struct pt_regs *regs)
> +asmlinkage void noinstr do_dsp(struct pt_regs *regs)
>  {
> +       irqentry_state_t state = irqentry_enter(regs);
> +
> +       local_irq_enable();
> +
>         if (cpu_has_dsp)
>                 panic("Unexpected DSP exception");
>
>         force_sig(SIGILL);
> +
> +       local_irq_disable();
> +       irqentry_exit(regs, state);
>  }
>
> -asmlinkage void do_reserved(struct pt_regs *regs)
> +asmlinkage void noinstr do_reserved(struct pt_regs *regs)
>  {
> +       irqentry_state_t state = irqentry_enter(regs);
> +
> +       local_irq_enable();
> +
>         /*
>          * Game over - no way to handle this if it ever occurs.  Most probably
>          * caused by a new unknown cpu type or after another deadly
> @@ -1657,6 +1705,9 @@ asmlinkage void do_reserved(struct pt_regs *regs)
>         show_regs(regs);
>         panic("Caught reserved exception %ld - should not happen.",
>               (regs->cp0_cause & 0x7f) >> 2);
> +
> +       local_irq_disable();
> +       irqentry_exit(regs, state);
>  }
>
>  static int __initdata l1parity = 1;
> @@ -1871,11 +1922,16 @@ asmlinkage void cache_parity_error(void)
>         panic("Can't handle the cache error!");
>  }
>
> -asmlinkage void do_ftlb(void)
> +asmlinkage void noinstr do_ftlb(struct pt_regs *regs)
>  {
> +       irqentry_state_t state = irqentry_enter(regs);
>         const int field = 2 * sizeof(unsigned long);
>         unsigned int reg_val;
>
> +       /* Enable interrupt if enabled in parent context */
> +       if (likely(!regs_irqs_disabled(regs)))
> +               local_irq_enable();
> +
>         /* For the moment, report the problem and hang. */
>         if ((cpu_has_mips_r2_r6) &&
>             (((current_cpu_data.processor_id & 0xff0000) == PRID_COMP_MIPS) ||
> @@ -1898,16 +1954,17 @@ asmlinkage void do_ftlb(void)
>         }
>         /* Just print the cacheerr bits for now */
>         cache_parity_error();
> +       local_irq_disable();
> +       irqentry_exit(regs, state);
>  }
>
> -asmlinkage void do_gsexc(struct pt_regs *regs, u32 diag1)
> +asmlinkage void noinstr do_gsexc(struct pt_regs *regs, u32 diag1)
>  {
> +       irqentry_state_t state = irqentry_enter(regs);
>         u32 exccode = (diag1 & LOONGSON_DIAG1_EXCCODE) >>
>                         LOONGSON_DIAG1_EXCCODE_SHIFT;
> -       enum ctx_state prev_state;
> -
> -       prev_state = exception_enter();
>
> +       local_irq_enable();
>         switch (exccode) {
>         case 0x08:
>                 /* Undocumented exception, will trigger on certain
> @@ -1928,7 +1985,30 @@ asmlinkage void do_gsexc(struct pt_regs *regs, u32 diag1)
>                 panic("Unhandled Loongson exception - GSCause = %08x", diag1);
>         }
>
> -       exception_exit(prev_state);
> +       local_irq_disable();
> +       irqentry_exit(regs, state);
> +}
> +
> +asmlinkage void noinstr do_int(struct pt_regs *regs)
> +{
> +       irqentry_state_t state = irqentry_enter(regs);
> +       struct pt_regs *old_regs = set_irq_regs(regs);
> +
> +       plat_irq_dispatch();
> +
> +       set_irq_regs(old_regs);
> +       irqentry_exit(regs, state);
> +}
> +
> +asmlinkage void noinstr do_vi(struct pt_regs *regs, vi_handler_t handler)
> +{
> +       irqentry_state_t state = irqentry_enter(regs);
> +       struct pt_regs *old_regs = set_irq_regs(regs);
> +
> +       handler();
> +
> +       set_irq_regs(old_regs);
> +       irqentry_exit(regs, state);
>  }
>
>  /*
> diff --git a/arch/mips/kernel/unaligned.c b/arch/mips/kernel/unaligned.c
> index df4b708c04a9..fe46016a6afc 100644
> --- a/arch/mips/kernel/unaligned.c
> +++ b/arch/mips/kernel/unaligned.c
> @@ -74,6 +74,7 @@
>   *      Undo the partial store in this case.
>   */
>  #include <linux/context_tracking.h>
> +#include <linux/entry-common.h>
>  #include <linux/mm.h>
>  #include <linux/signal.h>
>  #include <linux/smp.h>
> @@ -1472,12 +1473,15 @@ static void emulate_load_store_MIPS16e(struct pt_regs *regs, void __user * addr)
>         force_sig(SIGILL);
>  }
>
> -asmlinkage void do_ade(struct pt_regs *regs)
> +asmlinkage void noinstr do_ade(struct pt_regs *regs)
>  {
> -       enum ctx_state prev_state;
> +       irqentry_state_t state = irqentry_enter(regs);
>         unsigned int *pc;
>
> -       prev_state = exception_enter();
> +       /* Enable interrupt if enabled in parent context */
> +       if (likely(!regs_irqs_disabled(regs)))
> +               local_irq_enable();
> +
>         perf_sw_event(PERF_COUNT_SW_ALIGNMENT_FAULTS,
>                         1, regs, regs->cp0_badvaddr);
>         /*
> @@ -1530,16 +1534,15 @@ asmlinkage void do_ade(struct pt_regs *regs)
>
>         emulate_load_store_insn(regs, (void __user *)regs->cp0_badvaddr, pc);
>
> -       return;
> +       goto out;
>
>  sigbus:
>         die_if_kernel("Kernel unaligned instruction access", regs);
>         force_sig(SIGBUS);
>
> -       /*
> -        * XXX On return from the signal handler we should advance the epc
> -        */
> -       exception_exit(prev_state);
> +out:
> +       local_irq_disable();
> +       irqentry_exit(regs, state);
>  }
>
>  #ifdef CONFIG_DEBUG_FS
> diff --git a/arch/mips/mm/c-octeon.c b/arch/mips/mm/c-octeon.c
> index ec2ae501539a..e68c9e6c6480 100644
> --- a/arch/mips/mm/c-octeon.c
> +++ b/arch/mips/mm/c-octeon.c
> @@ -5,6 +5,7 @@
>   *
>   * Copyright (C) 2005-2007 Cavium Networks
>   */
> +#include <linux/entry-common.h>
>  #include <linux/export.h>
>  #include <linux/kernel.h>
>  #include <linux/sched.h>
> @@ -349,3 +350,17 @@ asmlinkage void cache_parity_error_octeon_non_recoverable(void)
>         co_cache_error_call_notifiers(1);
>         panic("Can't handle cache error: nested exception");
>  }
> +
> +asmlinkage void noinstr do_cache_err(struct pt_regs *regs)
> +{
> +       irqentry_state_t state = irqentry_enter(regs);
> +
> +       /* Enable interrupt if enabled in parent context */
> +       if (likely(!regs_irqs_disabled(regs)))
> +               local_irq_enable();
> +
> +       cache_parity_error_octeon_recoverable();
> +
> +       local_irq_disable();
> +       irqentry_exit(regs, state);
> +}
> diff --git a/arch/mips/mm/cex-oct.S b/arch/mips/mm/cex-oct.S
> index 9029092aa740..7d39087d208b 100644
> --- a/arch/mips/mm/cex-oct.S
> +++ b/arch/mips/mm/cex-oct.S
> @@ -60,11 +60,11 @@
>         .set    noat
>
>         SAVE_ALL
> -       KMODE
> -       jal     cache_parity_error_octeon_recoverable
> -       nop
> -       j       ret_from_exception
> +       CLI
> +       move    a0, sp
> +       jal     do_cache_err
>         nop
>
> +       RESTORE_ALL_AND_RET
>         .set pop
>         END(handle_cache_err)
> diff --git a/arch/mips/mm/fault.c b/arch/mips/mm/fault.c
> index e7abda9c013f..e55bd45a596b 100644
> --- a/arch/mips/mm/fault.c
> +++ b/arch/mips/mm/fault.c
> @@ -8,6 +8,7 @@
>  #include <linux/context_tracking.h>
>  #include <linux/signal.h>
>  #include <linux/sched.h>
> +#include <linux/entry-common.h>
>  #include <linux/interrupt.h>
>  #include <linux/kernel.h>
>  #include <linux/errno.h>
> @@ -327,9 +328,14 @@ static void __kprobes __do_page_fault(struct pt_regs *regs, unsigned long write,
>  asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
>         unsigned long write, unsigned long address)
>  {
> -       enum ctx_state prev_state;
> +       irqentry_state_t state = irqentry_enter(regs);
> +
> +       /* Enable interrupt if enabled in parent context */
> +       if (likely(!regs_irqs_disabled(regs)))
> +               local_irq_enable();
>
> -       prev_state = exception_enter();
>         __do_page_fault(regs, write, address);
> -       exception_exit(prev_state);
> +
> +       local_irq_disable();
> +       irqentry_exit(regs, state);
>  }
> diff --git a/arch/mips/mm/tlbex-fault.S b/arch/mips/mm/tlbex-fault.S
> index 77db401fc620..e16b4aa1fcc4 100644
> --- a/arch/mips/mm/tlbex-fault.S
> +++ b/arch/mips/mm/tlbex-fault.S
> @@ -15,12 +15,15 @@
>         .cfi_signal_frame
>         SAVE_ALL docfi=1
>         MFC0    a2, CP0_BADVADDR
> -       KMODE
> +       CLI
>         move    a0, sp
>         REG_S   a2, PT_BVADDR(sp)
>         li      a1, \write
>         jal     do_page_fault
> -       j       ret_from_exception
> +
> +       .set    noat
> +       RESTORE_ALL_AND_RET
> +       .set    at
>         END(tlb_do_page_fault_\write)
>         .endm
>
> --
> 2.27.0
>

^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: [PATCH 1/2] mips: convert syscall to generic entry
  2021-09-08  2:08     ` 陈飞扬
  2021-09-08  7:15       ` Huacai Chen
@ 2021-09-08  8:51       ` Thomas Bogendoerfer
  2021-09-08 12:41         ` Jiaxun Yang
                           ` (2 more replies)
  1 sibling, 3 replies; 15+ messages in thread
From: Thomas Bogendoerfer @ 2021-09-08  8:51 UTC (permalink / raw)
  To: 陈飞扬
  Cc: Jiaxun Yang, tglx, peterz, luto, arnd, Feiyang Chen, linux-mips,
	linux-arch, chenhuacai, Yanteng Si

On Wed, Sep 08, 2021 at 10:08:47AM +0800, 陈飞扬 wrote:
> On Tue, 7 Sept 2021 at 21:49, Jiaxun Yang <jiaxun.yang@flygoat.com> wrote:
> >
> >
> > 在 2021/9/7 14:16, FreeFlyingSheep 写道:
> > > From: Feiyang Chen <chenfeiyang@loongson.cn>
> > >
> > > Convert mips syscall to use the generic entry infrastructure from
> > > kernel/entry/*.
> > >
> > > There are a few special things on mips:
> > >
> > > - There is one type of syscall on mips32 (scall32-o32) and three types
> > > of syscalls on mips64 (scall64-o32, scall64-n32 and scall64-n64). Now
> > > convert to C code to handle different types of syscalls.
> > >
> > > - For some special syscalls (e.g. fork, clone, clone3 and sysmips),
> > > save_static_function() wrapper is used to save static registers. Now
> > > SAVE_STATIC is used in handle_sys before calling do_syscall(), so the
> > > save_static_function() wrapper can be removed.
> > >
> > > - For sigreturn/rt_sigreturn and sysmips, inline assembly is used to
> > > jump to syscall_exit directly for skipping setting the error flag and
> > > restoring all registers. Now use regs->regs[27] to mark whether to
> > > handle the error flag and always restore all registers in handle_sys,
> > > so these functions can return normally as other architecture.
> >
> > Hmm, that would give us overhead of register context on these syscalls.
> >
> > I guess it's worthy?
> >
> 
> Hi, Jiaxun,
> 
> Saving and restoring registers against different system calls can be
> difficult due to the use of generic entry.
> To avoid a lot of duplicate code, I think the overhead is worth it.

could you please provide numbers for that ? This code still runs
on low end MIPS CPUs for which overhead might mean a different
ballpark than some highend Loongson CPUs.

Thomas.

-- 
Crap can work. Given enough thrust pigs will fly, but it's not necessarily a
good idea.                                                [ RFC1925, 2.3 ]

^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: [PATCH 1/2] mips: convert syscall to generic entry
  2021-09-08  8:51       ` Thomas Bogendoerfer
@ 2021-09-08 12:41         ` Jiaxun Yang
  2021-09-09 12:45           ` Zhou Yanjie
  2021-09-13  1:35         ` teng sterling
  2021-09-14  1:30         ` Feiyang Chen
  2 siblings, 1 reply; 15+ messages in thread
From: Jiaxun Yang @ 2021-09-08 12:41 UTC (permalink / raw)
  To: Thomas Bogendoerfer, 陈飞扬
  Cc: tglx, peterz, luto, arnd, Feiyang Chen, linux-mips, linux-arch,
	chenhuacai, Yanteng Si, zhouyu


在 2021/9/8 16:51, Thomas Bogendoerfer 写道:
> On Wed, Sep 08, 2021 at 10:08:47AM +0800, 陈飞扬 wrote:
>> On Tue, 7 Sept 2021 at 21:49, Jiaxun Yang <jiaxun.yang@flygoat.com> wrote:
>>>
>>> 在 2021/9/7 14:16, FreeFlyingSheep 写道:
>>>> From: Feiyang Chen <chenfeiyang@loongson.cn>
>>>>
>>>> Convert mips syscall to use the generic entry infrastructure from
>>>> kernel/entry/*.
>>>>
>>>> There are a few special things on mips:
>>>>
>>>> - There is one type of syscall on mips32 (scall32-o32) and three types
>>>> of syscalls on mips64 (scall64-o32, scall64-n32 and scall64-n64). Now
>>>> convert to C code to handle different types of syscalls.
>>>>
>>>> - For some special syscalls (e.g. fork, clone, clone3 and sysmips),
>>>> save_static_function() wrapper is used to save static registers. Now
>>>> SAVE_STATIC is used in handle_sys before calling do_syscall(), so the
>>>> save_static_function() wrapper can be removed.
>>>>
>>>> - For sigreturn/rt_sigreturn and sysmips, inline assembly is used to
>>>> jump to syscall_exit directly for skipping setting the error flag and
>>>> restoring all registers. Now use regs->regs[27] to mark whether to
>>>> handle the error flag and always restore all registers in handle_sys,
>>>> so these functions can return normally as other architecture.
>>> Hmm, that would give us overhead of register context on these syscalls.
>>>
>>> I guess it's worthy?
>>>
>> Hi, Jiaxun,
>>
>> Saving and restoring registers against different system calls can be
>> difficult due to the use of generic entry.
>> To avoid a lot of duplicate code, I think the overhead is worth it.
> could you please provide numbers for that ? This code still runs
> on low end MIPS CPUs for which overhead might mean a different
> ballpark than some highend Loongson CPUs.

It shows ~3% regression for UnixBench on MT7621A (1004Kec).

+ Yanjie could you help with a run on ingenic platform?

Thanks.

- Jiaxun

>
> Thomas.
>

^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: [PATCH 1/2] mips: convert syscall to generic entry
  2021-09-08 12:41         ` Jiaxun Yang
@ 2021-09-09 12:45           ` Zhou Yanjie
  2021-09-13  2:51             ` Zhou Yanjie
  2021-09-13  5:16             ` H. Nikolaus Schaller
  0 siblings, 2 replies; 15+ messages in thread
From: Zhou Yanjie @ 2021-09-09 12:45 UTC (permalink / raw)
  To: Jiaxun Yang, Thomas Bogendoerfer, 陈飞扬,
	Paul Cercueil, H. Nikolaus Schaller
  Cc: tglx, peterz, luto, arnd, Feiyang Chen, linux-mips, linux-arch,
	chenhuacai, Yanteng Si

Hi,

On 2021/9/8 下午8:41, Jiaxun Yang wrote:
>
> 在 2021/9/8 16:51, Thomas Bogendoerfer 写道:
>> On Wed, Sep 08, 2021 at 10:08:47AM +0800, 陈飞扬 wrote:
>>> On Tue, 7 Sept 2021 at 21:49, Jiaxun Yang <jiaxun.yang@flygoat.com> 
>>> wrote:
>>>>
>>>> 在 2021/9/7 14:16, FreeFlyingSheep 写道:
>>>>> From: Feiyang Chen <chenfeiyang@loongson.cn>
>>>>>
>>>>> Convert mips syscall to use the generic entry infrastructure from
>>>>> kernel/entry/*.
>>>>>
>>>>> There are a few special things on mips:
>>>>>
>>>>> - There is one type of syscall on mips32 (scall32-o32) and three 
>>>>> types
>>>>> of syscalls on mips64 (scall64-o32, scall64-n32 and scall64-n64). Now
>>>>> convert to C code to handle different types of syscalls.
>>>>>
>>>>> - For some special syscalls (e.g. fork, clone, clone3 and sysmips),
>>>>> save_static_function() wrapper is used to save static registers. Now
>>>>> SAVE_STATIC is used in handle_sys before calling do_syscall(), so the
>>>>> save_static_function() wrapper can be removed.
>>>>>
>>>>> - For sigreturn/rt_sigreturn and sysmips, inline assembly is used to
>>>>> jump to syscall_exit directly for skipping setting the error flag and
>>>>> restoring all registers. Now use regs->regs[27] to mark whether to
>>>>> handle the error flag and always restore all registers in handle_sys,
>>>>> so these functions can return normally as other architecture.
>>>> Hmm, that would give us overhead of register context on these 
>>>> syscalls.
>>>>
>>>> I guess it's worthy?
>>>>
>>> Hi, Jiaxun,
>>>
>>> Saving and restoring registers against different system calls can be
>>> difficult due to the use of generic entry.
>>> To avoid a lot of duplicate code, I think the overhead is worth it.
>> could you please provide numbers for that ? This code still runs
>> on low end MIPS CPUs for which overhead might mean a different
>> ballpark than some highend Loongson CPUs.
>
> It shows ~3% regression for UnixBench on MT7621A (1004Kec).
>
> + Yanjie could you help with a run on ingenic platform?


Sure, I can help with JZ4775, JZ4780, X1000, X1830, X2000 from Ingenic, 
and SF16A18, SF19A2890 from SiFlower.

+ Paul could you help with a run on JZ4760 and JZ4770?

+ Nikolaus could you help with a run on JZ4730?


Thanks and best regards!


>
> Thanks.
>
> - Jiaxun
>
>>
>> Thomas.
>>

^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: [PATCH 1/2] mips: convert syscall to generic entry
  2021-09-08  8:51       ` Thomas Bogendoerfer
  2021-09-08 12:41         ` Jiaxun Yang
@ 2021-09-13  1:35         ` teng sterling
  2021-09-14  1:30         ` Feiyang Chen
  2 siblings, 0 replies; 15+ messages in thread
From: teng sterling @ 2021-09-13  1:35 UTC (permalink / raw)
  To: Thomas Bogendoerfer
  Cc: 陈飞扬,
	Jiaxun Yang, tglx, peterz, luto, arnd, Feiyang Chen, linux-mips,
	linux-arch, Huacai Chen, Yanteng Si

Thomas Bogendoerfer <tsbogend@alpha.franken.de> 于2021年9月8日周三 下午5:36写道:
>
> On Wed, Sep 08, 2021 at 10:08:47AM +0800, 陈飞扬 wrote:
> > On Tue, 7 Sept 2021 at 21:49, Jiaxun Yang <jiaxun.yang@flygoat.com> wrote:
> > >
> > >
> > > 在 2021/9/7 14:16, FreeFlyingSheep 写道:
> > > > From: Feiyang Chen <chenfeiyang@loongson.cn>
> > > >
> > > > Convert mips syscall to use the generic entry infrastructure from
> > > > kernel/entry/*.
> > > >
> > > > There are a few special things on mips:
> > > >
> > > > - There is one type of syscall on mips32 (scall32-o32) and three types
> > > > of syscalls on mips64 (scall64-o32, scall64-n32 and scall64-n64). Now
> > > > convert to C code to handle different types of syscalls.
> > > >
> > > > - For some special syscalls (e.g. fork, clone, clone3 and sysmips),
> > > > save_static_function() wrapper is used to save static registers. Now
> > > > SAVE_STATIC is used in handle_sys before calling do_syscall(), so the
> > > > save_static_function() wrapper can be removed.
> > > >
> > > > - For sigreturn/rt_sigreturn and sysmips, inline assembly is used to
> > > > jump to syscall_exit directly for skipping setting the error flag and
> > > > restoring all registers. Now use regs->regs[27] to mark whether to
> > > > handle the error flag and always restore all registers in handle_sys,
> > > > so these functions can return normally as other architecture.
> > >
> > > Hmm, that would give us overhead of register context on these syscalls.
> > >
> > > I guess it's worthy?
> > >
> >
> > Hi, Jiaxun,
> >
> > Saving and restoring registers against different system calls can be
> > difficult due to the use of generic entry.
> > To avoid a lot of duplicate code, I think the overhead is worth it.
>
> could you please provide numbers for that ? This code still runs
> on low end MIPS CPUs for which overhead might mean a different
> ballpark than some highend Loongson CPUs.
It shows ~2% regression for UnixBench on LOONGSON 3a4000 (a1901).

Thanks,

Yanteng

^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: [PATCH 1/2] mips: convert syscall to generic entry
  2021-09-09 12:45           ` Zhou Yanjie
@ 2021-09-13  2:51             ` Zhou Yanjie
  2021-09-13  3:06               ` Zhou Yanjie
  2021-09-13  5:16             ` H. Nikolaus Schaller
  1 sibling, 1 reply; 15+ messages in thread
From: Zhou Yanjie @ 2021-09-13  2:51 UTC (permalink / raw)
  To: Jiaxun Yang, Thomas Bogendoerfer, 陈飞扬,
	Paul Cercueil, H. Nikolaus Schaller
  Cc: tglx, peterz, luto, arnd, Feiyang Chen, linux-mips, linux-arch,
	chenhuacai, Yanteng Si

Hi,

On 2021/9/9 下午8:45, Zhou Yanjie wrote:
> Hi,
>
> On 2021/9/8 下午8:41, Jiaxun Yang wrote:
>>
>> 在 2021/9/8 16:51, Thomas Bogendoerfer 写道:
>>> On Wed, Sep 08, 2021 at 10:08:47AM +0800, 陈飞扬 wrote:
>>>> On Tue, 7 Sept 2021 at 21:49, Jiaxun Yang <jiaxun.yang@flygoat.com> 
>>>> wrote:
>>>>>
>>>>> 在 2021/9/7 14:16, FreeFlyingSheep 写道:
>>>>>> From: Feiyang Chen <chenfeiyang@loongson.cn>
>>>>>>
>>>>>> Convert mips syscall to use the generic entry infrastructure from
>>>>>> kernel/entry/*.
>>>>>>
>>>>>> There are a few special things on mips:
>>>>>>
>>>>>> - There is one type of syscall on mips32 (scall32-o32) and three 
>>>>>> types
>>>>>> of syscalls on mips64 (scall64-o32, scall64-n32 and scall64-n64). 
>>>>>> Now
>>>>>> convert to C code to handle different types of syscalls.
>>>>>>
>>>>>> - For some special syscalls (e.g. fork, clone, clone3 and sysmips),
>>>>>> save_static_function() wrapper is used to save static registers. Now
>>>>>> SAVE_STATIC is used in handle_sys before calling do_syscall(), so 
>>>>>> the
>>>>>> save_static_function() wrapper can be removed.
>>>>>>
>>>>>> - For sigreturn/rt_sigreturn and sysmips, inline assembly is used to
>>>>>> jump to syscall_exit directly for skipping setting the error flag 
>>>>>> and
>>>>>> restoring all registers. Now use regs->regs[27] to mark whether to
>>>>>> handle the error flag and always restore all registers in 
>>>>>> handle_sys,
>>>>>> so these functions can return normally as other architecture.
>>>>> Hmm, that would give us overhead of register context on these 
>>>>> syscalls.
>>>>>
>>>>> I guess it's worthy?
>>>>>
>>>> Hi, Jiaxun,
>>>>
>>>> Saving and restoring registers against different system calls can be
>>>> difficult due to the use of generic entry.
>>>> To avoid a lot of duplicate code, I think the overhead is worth it.
>>> could you please provide numbers for that ? This code still runs
>>> on low end MIPS CPUs for which overhead might mean a different
>>> ballpark than some highend Loongson CPUs.
>>
>> It shows ~3% regression for UnixBench on MT7621A (1004Kec).
>>
>> + Yanjie could you help with a run on ingenic platform?
>
>
> Sure, I can help with JZ4775, JZ4780, X1000, X1830, X2000 from 
> Ingenic, and SF16A18, SF19A2890 from SiFlower.


Sorry for the delay.

I encountered some troubles when testing UNIX Bench on the Ingenic 
X2000(SMT on) and two SiFlower processors,
so I ended up with only the following test results:


Score Without Patches    Score With Patches    Performance Change    SoC 
Model
             105.9                                    101.2             
          -4.4%                         JZ4775
             132.4                                    122.0             
          -7.9%                         JZ4780(SMP off)
             170.2                                    149.5             
        -12.2%                         JZ4780(SMP on)
             101.3                                      89.0             
        -12.1%                         X1000E
             187.1                                    177.7             
          -5.0%                         X1830
             324.9                                    312.2             
          -3.9%                         X2000(SMT off)


On the whole, the impact on performance is quite huge.


Thanks and best regards!


>
> + Paul could you help with a run on JZ4760 and JZ4770?
>
> + Nikolaus could you help with a run on JZ4730?
>
>
> Thanks and best regards!
>
>
>>
>> Thanks.
>>
>> - Jiaxun
>>
>>>
>>> Thomas.
>>>

^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: [PATCH 1/2] mips: convert syscall to generic entry
  2021-09-13  2:51             ` Zhou Yanjie
@ 2021-09-13  3:06               ` Zhou Yanjie
  0 siblings, 0 replies; 15+ messages in thread
From: Zhou Yanjie @ 2021-09-13  3:06 UTC (permalink / raw)
  To: Zhou Yanjie, Jiaxun Yang, Thomas Bogendoerfer,
	陈飞扬,
	Paul Cercueil, H. Nikolaus Schaller
  Cc: tglx, peterz, luto, arnd, Feiyang Chen, linux-mips, linux-arch,
	chenhuacai, Yanteng Si


On 2021/9/13 上午10:51, Zhou Yanjie wrote:
> Hi,
>
> On 2021/9/9 下午8:45, Zhou Yanjie wrote:
>> Hi,
>>
>> On 2021/9/8 下午8:41, Jiaxun Yang wrote:
>>>
>>> 在 2021/9/8 16:51, Thomas Bogendoerfer 写道:
>>>> On Wed, Sep 08, 2021 at 10:08:47AM +0800, 陈飞扬 wrote:
>>>>> On Tue, 7 Sept 2021 at 21:49, Jiaxun Yang 
>>>>> <jiaxun.yang@flygoat.com> wrote:
>>>>>>
>>>>>> 在 2021/9/7 14:16, FreeFlyingSheep 写道:
>>>>>>> From: Feiyang Chen <chenfeiyang@loongson.cn>
>>>>>>>
>>>>>>> Convert mips syscall to use the generic entry infrastructure from
>>>>>>> kernel/entry/*.
>>>>>>>
>>>>>>> There are a few special things on mips:
>>>>>>>
>>>>>>> - There is one type of syscall on mips32 (scall32-o32) and three 
>>>>>>> types
>>>>>>> of syscalls on mips64 (scall64-o32, scall64-n32 and 
>>>>>>> scall64-n64). Now
>>>>>>> convert to C code to handle different types of syscalls.
>>>>>>>
>>>>>>> - For some special syscalls (e.g. fork, clone, clone3 and sysmips),
>>>>>>> save_static_function() wrapper is used to save static registers. 
>>>>>>> Now
>>>>>>> SAVE_STATIC is used in handle_sys before calling do_syscall(), 
>>>>>>> so the
>>>>>>> save_static_function() wrapper can be removed.
>>>>>>>
>>>>>>> - For sigreturn/rt_sigreturn and sysmips, inline assembly is 
>>>>>>> used to
>>>>>>> jump to syscall_exit directly for skipping setting the error 
>>>>>>> flag and
>>>>>>> restoring all registers. Now use regs->regs[27] to mark whether to
>>>>>>> handle the error flag and always restore all registers in 
>>>>>>> handle_sys,
>>>>>>> so these functions can return normally as other architecture.
>>>>>> Hmm, that would give us overhead of register context on these 
>>>>>> syscalls.
>>>>>>
>>>>>> I guess it's worthy?
>>>>>>
>>>>> Hi, Jiaxun,
>>>>>
>>>>> Saving and restoring registers against different system calls can be
>>>>> difficult due to the use of generic entry.
>>>>> To avoid a lot of duplicate code, I think the overhead is worth it.
>>>> could you please provide numbers for that ? This code still runs
>>>> on low end MIPS CPUs for which overhead might mean a different
>>>> ballpark than some highend Loongson CPUs.
>>>
>>> It shows ~3% regression for UnixBench on MT7621A (1004Kec).
>>>
>>> + Yanjie could you help with a run on ingenic platform?
>>
>>
>> Sure, I can help with JZ4775, JZ4780, X1000, X1830, X2000 from 
>> Ingenic, and SF16A18, SF19A2890 from SiFlower.
>
>
> Sorry for the delay.
>
> I encountered some troubles when testing UNIX Bench on the Ingenic 
> X2000(SMT on) and two SiFlower processors,
> so I ended up with only the following test results:
>
>
> Score Without Patches    Score With Patches    Performance Change    
> SoC Model
>             105.9                                    101.2          
>     -4.4%                         JZ4775
>             132.4                                    122.0          
>     -7.9%                         JZ4780(SMP off)
>             170.2                                    149.5            
> -12.2%                         JZ4780(SMP on)
>             101.3                                      89.0         
>        -12.1%                         X1000E
>             187.1                                    177.7          
>     -5.0%                         X1830
>             324.9                                    312.2          
>     -3.9%                         X2000(SMT off)


Apologies for the bad format :(


Score Without Patches  Score With Patches  Performance Change SoC Model
        105.9                101.2              -4.4% JZ4775
        132.4                122.0              -7.9% JZ4780(SMP off)
        170.2                149.5             -12.2% JZ4780(SMP on)
        101.3                 89.0             -12.1% X1000E
        187.1                177.7              -5.0% X1830
        324.9                312.2              -3.9% X2000(SMT off)


>
>
> On the whole, the impact on performance is quite huge.
>
>
> Thanks and best regards!
>
>
>>
>> + Paul could you help with a run on JZ4760 and JZ4770?
>>
>> + Nikolaus could you help with a run on JZ4730?
>>
>>
>> Thanks and best regards!
>>
>>
>>>
>>> Thanks.
>>>
>>> - Jiaxun
>>>
>>>>
>>>> Thomas.
>>>>

^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: [PATCH 1/2] mips: convert syscall to generic entry
  2021-09-09 12:45           ` Zhou Yanjie
  2021-09-13  2:51             ` Zhou Yanjie
@ 2021-09-13  5:16             ` H. Nikolaus Schaller
  1 sibling, 0 replies; 15+ messages in thread
From: H. Nikolaus Schaller @ 2021-09-13  5:16 UTC (permalink / raw)
  To: Zhou Yanjie, Jiaxun Yang, Feiyang Chen, Thomas Bogendoerfer,
	陈飞扬
  Cc: Paul Cercueil, Thomas Gleixner, peterz, luto, Arnd Bergmann,
	linux-mips, linux-arch, Huacai Chen, Yanteng Si

Hi,


> Am 09.09.2021 um 14:45 schrieb Zhou Yanjie <zhouyu@wanyeetech.com>:
> 
> Hi,
> 
> On 2021/9/8 下午8:41, Jiaxun Yang wrote:
>> 
>> 在 2021/9/8 16:51, Thomas Bogendoerfer 写道:
>>> On Wed, Sep 08, 2021 at 10:08:47AM +0800, 陈飞扬 wrote:
>>>> On Tue, 7 Sept 2021 at 21:49, Jiaxun Yang <jiaxun.yang@flygoat.com> wrote:
>>>>> 
>>>>> 在 2021/9/7 14:16, FreeFlyingSheep 写道:
>>>>>> From: Feiyang Chen <chenfeiyang@loongson.cn>
>>>>>> 
>>>>>> Convert mips syscall to use the generic entry infrastructure from
>>>>>> kernel/entry/*.
>>>>>> 
>>>>>> There are a few special things on mips:
>>>>>> 
>>>>>> - There is one type of syscall on mips32 (scall32-o32) and three types
>>>>>> of syscalls on mips64 (scall64-o32, scall64-n32 and scall64-n64). Now
>>>>>> convert to C code to handle different types of syscalls.
>>>>>> 
>>>>>> - For some special syscalls (e.g. fork, clone, clone3 and sysmips),
>>>>>> save_static_function() wrapper is used to save static registers. Now
>>>>>> SAVE_STATIC is used in handle_sys before calling do_syscall(), so the
>>>>>> save_static_function() wrapper can be removed.
>>>>>> 
>>>>>> - For sigreturn/rt_sigreturn and sysmips, inline assembly is used to
>>>>>> jump to syscall_exit directly for skipping setting the error flag and
>>>>>> restoring all registers. Now use regs->regs[27] to mark whether to
>>>>>> handle the error flag and always restore all registers in handle_sys,
>>>>>> so these functions can return normally as other architecture.
>>>>> Hmm, that would give us overhead of register context on these syscalls.
>>>>> 
>>>>> I guess it's worthy?
>>>>> 
>>>> Hi, Jiaxun,
>>>> 
>>>> Saving and restoring registers against different system calls can be
>>>> difficult due to the use of generic entry.
>>>> To avoid a lot of duplicate code, I think the overhead is worth it.
>>> could you please provide numbers for that ? This code still runs
>>> on low end MIPS CPUs for which overhead might mean a different
>>> ballpark than some highend Loongson CPUs.
>> 
>> It shows ~3% regression for UnixBench on MT7621A (1004Kec).
>> 
>> + Yanjie could you help with a run on ingenic platform?
> 
> 
> Sure, I can help with JZ4775, JZ4780, X1000, X1830, X2000 from Ingenic, and SF16A18, SF19A2890 from SiFlower.
> 
> + Paul could you help with a run on JZ4760 and JZ4770?
> 
> + Nikolaus could you help with a run on JZ4730?

Have not observed a negative effect on jz4730. Same for jz4780.
But I have not done performance tests.

BR,
Nikolaus

^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: [PATCH 1/2] mips: convert syscall to generic entry
  2021-09-08  8:51       ` Thomas Bogendoerfer
  2021-09-08 12:41         ` Jiaxun Yang
  2021-09-13  1:35         ` teng sterling
@ 2021-09-14  1:30         ` Feiyang Chen
  2 siblings, 0 replies; 15+ messages in thread
From: Feiyang Chen @ 2021-09-14  1:30 UTC (permalink / raw)
  To: Thomas Bogendoerfer
  Cc: Jiaxun Yang, tglx, peterz, luto, arnd, Feiyang Chen, linux-mips,
	linux-arch, chenhuacai, Yanteng Si, Zhou Yanjie,
	H. Nikolaus Schaller

On Wed, 8 Sept 2021 at 17:28, Thomas Bogendoerfer
<tsbogend@alpha.franken.de> wrote:
>
> On Wed, Sep 08, 2021 at 10:08:47AM +0800, 陈飞扬 wrote:
> > On Tue, 7 Sept 2021 at 21:49, Jiaxun Yang <jiaxun.yang@flygoat.com> wrote:
> > >
> > >
> > > 在 2021/9/7 14:16, FreeFlyingSheep 写道:
> > > > From: Feiyang Chen <chenfeiyang@loongson.cn>
> > > >
> > > > Convert mips syscall to use the generic entry infrastructure from
> > > > kernel/entry/*.
> > > >
> > > > There are a few special things on mips:
> > > >
> > > > - There is one type of syscall on mips32 (scall32-o32) and three types
> > > > of syscalls on mips64 (scall64-o32, scall64-n32 and scall64-n64). Now
> > > > convert to C code to handle different types of syscalls.
> > > >
> > > > - For some special syscalls (e.g. fork, clone, clone3 and sysmips),
> > > > save_static_function() wrapper is used to save static registers. Now
> > > > SAVE_STATIC is used in handle_sys before calling do_syscall(), so the
> > > > save_static_function() wrapper can be removed.
> > > >
> > > > - For sigreturn/rt_sigreturn and sysmips, inline assembly is used to
> > > > jump to syscall_exit directly for skipping setting the error flag and
> > > > restoring all registers. Now use regs->regs[27] to mark whether to
> > > > handle the error flag and always restore all registers in handle_sys,
> > > > so these functions can return normally as other architecture.
> > >
> > > Hmm, that would give us overhead of register context on these syscalls.
> > >
> > > I guess it's worthy?
> > >
> >
> > Hi, Jiaxun,
> >
> > Saving and restoring registers against different system calls can be
> > difficult due to the use of generic entry.
> > To avoid a lot of duplicate code, I think the overhead is worth it.
>
> could you please provide numbers for that ? This code still runs
> on low end MIPS CPUs for which overhead might mean a different
> ballpark than some highend Loongson CPUs.

Hi, Thomas, Jiaxun, Yanjie, Nikolaus,

Thank you for your help. The impact on performance seems somewhat
significant, I will make improvements in the v2 of the patchset.

Thanks,
Feiyang

>
> Thomas.
>
> --
> Crap can work. Given enough thrust pigs will fly, but it's not necessarily a
> good idea.                                                [ RFC1925, 2.3 ]

^ permalink raw reply	[flat|nested] 15+ messages in thread

end of thread, other threads:[~2021-09-14  1:30 UTC | newest]

Thread overview: 15+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-09-07  6:16 [PATCH 0/2] mips: convert to generic entry FreeFlyingSheep
2021-09-07  6:16 ` [PATCH 1/2] mips: convert syscall " FreeFlyingSheep
2021-09-07 13:48   ` Jiaxun Yang
2021-09-08  2:08     ` 陈飞扬
2021-09-08  7:15       ` Huacai Chen
2021-09-08  8:51       ` Thomas Bogendoerfer
2021-09-08 12:41         ` Jiaxun Yang
2021-09-09 12:45           ` Zhou Yanjie
2021-09-13  2:51             ` Zhou Yanjie
2021-09-13  3:06               ` Zhou Yanjie
2021-09-13  5:16             ` H. Nikolaus Schaller
2021-09-13  1:35         ` teng sterling
2021-09-14  1:30         ` Feiyang Chen
2021-09-07  6:16 ` [PATCH 2/2] mips: convert irq " FreeFlyingSheep
2021-09-08  7:17   ` Huacai Chen

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