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* [PATCH v2 0/2] MIPS: convert to generic entry
@ 2021-09-14  1:50 Feiyang Chen
  2021-09-14  1:50 ` [PATCH v2 1/2] MIPS: convert syscall " Feiyang Chen
                   ` (2 more replies)
  0 siblings, 3 replies; 13+ messages in thread
From: Feiyang Chen @ 2021-09-14  1:50 UTC (permalink / raw)
  To: tsbogend, tglx, peterz, luto, arnd
  Cc: Feiyang Chen, linux-mips, linux-arch, chenhuacai, jiaxun.yang,
	zhouyu, hns, chris.chenfeiyang

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

v2: Use regs->regs[27] to mark whether to restore all registers in
handle_sys and enable IRQ stack.

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                  | 150 +++------------
 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                  | 136 +++++++++++++
 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                | 148 +++++++++++---
 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                  | 225 ++++++++++++++++------
 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, 594 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] 13+ messages in thread

* [PATCH v2 1/2] MIPS: convert syscall to generic entry
  2021-09-14  1:50 [PATCH v2 0/2] MIPS: convert to generic entry Feiyang Chen
@ 2021-09-14  1:50 ` Feiyang Chen
  2021-09-14  1:50 ` [PATCH v2 2/2] MIPS: convert irq " Feiyang Chen
  2021-09-14  8:54 ` [PATCH v2 0/2] MIPS: convert " Jiaxun Yang
  2 siblings, 0 replies; 13+ messages in thread
From: Feiyang Chen @ 2021-09-14  1:50 UTC (permalink / raw)
  To: tsbogend, tglx, peterz, luto, arnd
  Cc: Feiyang Chen, linux-mips, linux-arch, chenhuacai, jiaxun.yang,
	zhouyu, hns, chris.chenfeiyang, Yanteng Si

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 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>
Reviewed-by: Huacai Chen <chenhuacai@kernel.org>
---
 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                  | 137 +++++++++++++
 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                | 148 +++++++++++---
 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, 349 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..fae8d99f0458
--- /dev/null
+++ b/arch/mips/kernel/scall.S
@@ -0,0 +1,137 @@
+/* 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
+	beqz	v0, 1f				# restore all registers?
+	nop
+
+	.set	noat
+	RESTORE_TEMP
+	RESTORE_STATIC
+	RESTORE_AT
+1:	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..2653f82a8c99 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 +229,121 @@ 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);
+
+long 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 (unlikely(!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);
+	return regs->regs[27];
+}
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] 13+ messages in thread

* [PATCH v2 2/2] MIPS: convert irq to generic entry
  2021-09-14  1:50 [PATCH v2 0/2] MIPS: convert to generic entry Feiyang Chen
  2021-09-14  1:50 ` [PATCH v2 1/2] MIPS: convert syscall " Feiyang Chen
@ 2021-09-14  1:50 ` Feiyang Chen
  2021-09-14  8:54 ` [PATCH v2 0/2] MIPS: convert " Jiaxun Yang
  2 siblings, 0 replies; 13+ messages in thread
From: Feiyang Chen @ 2021-09-14  1:50 UTC (permalink / raw)
  To: tsbogend, tglx, peterz, luto, arnd
  Cc: Feiyang Chen, linux-mips, linux-arch, chenhuacai, jiaxun.yang,
	zhouyu, hns, chris.chenfeiyang, Yanteng Si

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.

Use call_on_irq_stack() to help invoking a function on IRQ stack.

Signed-off-by: Feiyang Chen <chenfeiyang@loongson.cn>
Signed-off-by: Yanteng Si <siyanteng@loongson.cn>
Reviewed-by: Huacai Chen <chenhuacai@kernel.org>
---
 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           | 150 ++++---------------
 arch/mips/kernel/head.S            |   1 -
 arch/mips/kernel/r4k-bugs64.c      |  14 +-
 arch/mips/kernel/scall.S           |   1 -
 arch/mips/kernel/signal.c          |  26 ----
 arch/mips/kernel/traps.c           | 225 +++++++++++++++++++++--------
 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, 254 insertions(+), 356 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..aa04eb131379 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 +181,17 @@ 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
+	move	a1, sp
+	jal	do_int
 #ifdef CONFIG_CPU_MICROMIPS
 	nop
 #endif
+
+	.set	noat
+	RESTORE_ALL_AND_RET
+	.set	at
 	END(handle_int)
 
 	__INIT
@@ -290,54 +253,13 @@ 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, sp
+	move	a2, v0
+	jal	do_vi
 
-	j	ret_from_irq
+	RESTORE_ALL_AND_RET
 	END(except_vec_vi_handler)
 
 /*
@@ -462,22 +384,12 @@ 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 +400,13 @@ 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 +418,7 @@ 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 +457,7 @@ 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 +469,28 @@ 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 +584,5 @@ 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 fae8d99f0458..bd2e05304e72 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>
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..5c4be5440b15 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>
@@ -40,6 +41,7 @@
 #include <linux/perf_event.h>
 
 #include <asm/addrspace.h>
+#include <asm/asm-offsets.h>
 #include <asm/bootinfo.h>
 #include <asm/branch.h>
 #include <asm/break.h>
@@ -438,15 +440,14 @@ 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 +487,7 @@ asmlinkage void do_be(struct pt_regs *regs)
 	force_sig(SIGBUS);
 
 out:
-	exception_exit(prev_state);
+	irqentry_exit(regs, state);
 }
 
 /*
@@ -743,15 +744,18 @@ 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 +869,12 @@ 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 +919,8 @@ 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 +1022,16 @@ 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 +1103,8 @@ 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 +1112,17 @@ 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 +1143,8 @@ 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 +1152,19 @@ 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 +1191,6 @@ 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 +1246,8 @@ asmlinkage void do_ri(struct pt_regs *regs)
 	}
 
 out:
-	exception_exit(prev_state);
+	local_irq_disable();
+	irqentry_exit(regs, state);
 }
 
 /*
@@ -1393,16 +1407,17 @@ 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 +1510,14 @@ 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 +1529,18 @@ 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 +1552,39 @@ 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 +1604,16 @@ 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 +1631,17 @@ 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 +1671,33 @@ 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 +1706,9 @@ 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 +1923,16 @@ 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 +1955,17 @@ 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 +1986,52 @@ 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);
+}
+
+static void noinstr call_on_irq_stack(struct pt_regs *regs,
+	unsigned long sp, void (*func)(void))
+{
+	int cpu;
+	unsigned long stack;
+	irqentry_state_t state = irqentry_enter(regs);
+	struct pt_regs *old_regs = set_irq_regs(regs);
+
+	cpu = smp_processor_id();
+
+	if (on_irq_stack(cpu, sp)) {
+		func();
+	} else {
+		stack = (unsigned long)irq_stack[cpu] + _IRQ_STACK_START;
+
+		/* Save task's sp on IRQ stack so that unwinding can follow it */
+		*(unsigned long *)stack = sp;
+
+		__asm__ __volatile__(
+		"move	$16, $29	\n" /* Preserve sp */
+		"move	$29, %[stack]	\n" /* Switch to IRQ stack */
+		"jalr	%[func]		\n" /* Invoke func */
+		"move	$29, $16	\n" /* Restore sp */
+		: /* No outputs */
+		: [stack] "r" (stack), [func] "r" (func)
+		: "$2", "$3", "$4", "$5", "$6", "$7", "$8", "$9", "$10", "$11",
+		  "$12", "$13", "$14", "$15", "$16", "$24", "$25", "memory");
+	}
+
+	set_irq_regs(old_regs);
+	irqentry_exit(regs, state);
+}
+
+asmlinkage void noinstr do_int(struct pt_regs *regs, unsigned long sp)
+{
+	call_on_irq_stack(regs, sp, plat_irq_dispatch);
+}
+
+asmlinkage void noinstr do_vi(struct pt_regs *regs, unsigned long sp,
+	vi_handler_t handler)
+{
+	call_on_irq_stack(regs, sp, handler);
 }
 
 /*
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] 13+ messages in thread

* Re: [PATCH v2 0/2] MIPS: convert to generic entry
  2021-09-14  1:50 [PATCH v2 0/2] MIPS: convert to generic entry Feiyang Chen
  2021-09-14  1:50 ` [PATCH v2 1/2] MIPS: convert syscall " Feiyang Chen
  2021-09-14  1:50 ` [PATCH v2 2/2] MIPS: convert irq " Feiyang Chen
@ 2021-09-14  8:54 ` Jiaxun Yang
  2021-09-14  9:30   ` Feiyang Chen
  2 siblings, 1 reply; 13+ messages in thread
From: Jiaxun Yang @ 2021-09-14  8:54 UTC (permalink / raw)
  To: Feiyang Chen, tsbogend, tglx, peterz, luto, arnd
  Cc: Feiyang Chen, linux-mips, linux-arch, chenhuacai, zhouyu, hns



在 2021/9/14 2:50, Feiyang Chen 写道:
> Convert MIPS to use the generic entry infrastructure from
> kernel/entry/*.
>
> v2: Use regs->regs[27] to mark whether to restore all registers in
> handle_sys and enable IRQ stack.
Hi Feiyang,

Thanks for your patch, could you please expand how could this improve 
the performance?

Thanks.
- Jiaxun
>
> 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                  | 150 +++------------
>   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                  | 136 +++++++++++++
>   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                | 148 +++++++++++---
>   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                  | 225 ++++++++++++++++------
>   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, 594 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
>


^ permalink raw reply	[flat|nested] 13+ messages in thread

* Re: [PATCH v2 0/2] MIPS: convert to generic entry
  2021-09-14  8:54 ` [PATCH v2 0/2] MIPS: convert " Jiaxun Yang
@ 2021-09-14  9:30   ` Feiyang Chen
  2021-09-21 15:57     ` Thomas Bogendoerfer
  0 siblings, 1 reply; 13+ messages in thread
From: Feiyang Chen @ 2021-09-14  9:30 UTC (permalink / raw)
  To: Jiaxun Yang
  Cc: Thomas Bogendoerfer, tglx, peterz, luto, arnd, Feiyang Chen,
	linux-mips, linux-arch, chenhuacai, Zhou Yanjie,
	H. Nikolaus Schaller

On Tue, 14 Sept 2021 at 16:54, Jiaxun Yang <jiaxun.yang@flygoat.com> wrote:
>
>
>
> 在 2021/9/14 2:50, Feiyang Chen 写道:
> > Convert MIPS to use the generic entry infrastructure from
> > kernel/entry/*.
> >
> > v2: Use regs->regs[27] to mark whether to restore all registers in
> > handle_sys and enable IRQ stack.
> Hi Feiyang,
>
> Thanks for your patch, could you please expand how could this improve
> the performance?
>

Hi, Jiaxun,

We always restore all registers in handle_sys in the v1 of the
patchset. Since regs->regs[27] is marked where we need to restore all
registers, now we simply use it as the return value of do_syscall to
determine whether we can only restore partial registers in handle_sys.

+       move    a0, sp
+       jal     do_syscall
+       beqz    v0, 1f                          # restore all registers?
+       nop
+
+       .set    noat
+       RESTORE_TEMP
+       RESTORE_STATIC
+       RESTORE_AT
+1:     RESTORE_SOME
+       RESTORE_SP_AND_RET
+       .set    at

Thanks,
Feiyang

> Thanks.
> - Jiaxun
> >
> > 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                  | 150 +++------------
> >   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                  | 136 +++++++++++++
> >   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                | 148 +++++++++++---
> >   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                  | 225 ++++++++++++++++------
> >   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, 594 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
> >
>

^ permalink raw reply	[flat|nested] 13+ messages in thread

* Re: [PATCH v2 0/2] MIPS: convert to generic entry
  2021-09-14  9:30   ` Feiyang Chen
@ 2021-09-21 15:57     ` Thomas Bogendoerfer
  2021-09-23 14:33       ` Zhou Yanjie
  2021-09-23 23:51       ` Jiaxun Yang
  0 siblings, 2 replies; 13+ messages in thread
From: Thomas Bogendoerfer @ 2021-09-21 15:57 UTC (permalink / raw)
  To: Feiyang Chen
  Cc: Jiaxun Yang, tglx, peterz, luto, arnd, Feiyang Chen, linux-mips,
	linux-arch, chenhuacai, Zhou Yanjie, H. Nikolaus Schaller

On Tue, Sep 14, 2021 at 05:30:14PM +0800, Feiyang Chen wrote:
> On Tue, 14 Sept 2021 at 16:54, Jiaxun Yang <jiaxun.yang@flygoat.com> wrote:
> >
> >
> >
> > 在 2021/9/14 2:50, Feiyang Chen 写道:
> > > Convert MIPS to use the generic entry infrastructure from
> > > kernel/entry/*.
> > >
> > > v2: Use regs->regs[27] to mark whether to restore all registers in
> > > handle_sys and enable IRQ stack.
> > Hi Feiyang,
> >
> > Thanks for your patch, could you please expand how could this improve
> > the performance?
> >
> 
> Hi, Jiaxun,
> 
> We always restore all registers in handle_sys in the v1 of the
> patchset. Since regs->regs[27] is marked where we need to restore all
> registers, now we simply use it as the return value of do_syscall to
> determine whether we can only restore partial registers in handle_sys.

can people, who provided performance numbers for v1 do the same for v2 ?

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] 13+ messages in thread

* Re: [PATCH v2 0/2] MIPS: convert to generic entry
  2021-09-21 15:57     ` Thomas Bogendoerfer
@ 2021-09-23 14:33       ` Zhou Yanjie
  2021-10-13 15:00         ` Zhou Yanjie
  2021-09-23 23:51       ` Jiaxun Yang
  1 sibling, 1 reply; 13+ messages in thread
From: Zhou Yanjie @ 2021-09-23 14:33 UTC (permalink / raw)
  To: Thomas Bogendoerfer, Feiyang Chen
  Cc: Jiaxun Yang, tglx, peterz, luto, arnd, Feiyang Chen, linux-mips,
	linux-arch, chenhuacai, H. Nikolaus Schaller

Hi Thomas,

On 2021/9/21 下午11:57, Thomas Bogendoerfer wrote:
> On Tue, Sep 14, 2021 at 05:30:14PM +0800, Feiyang Chen wrote:
>> On Tue, 14 Sept 2021 at 16:54, Jiaxun Yang <jiaxun.yang@flygoat.com> wrote:
>>>
>>>
>>> 在 2021/9/14 2:50, Feiyang Chen 写道:
>>>> Convert MIPS to use the generic entry infrastructure from
>>>> kernel/entry/*.
>>>>
>>>> v2: Use regs->regs[27] to mark whether to restore all registers in
>>>> handle_sys and enable IRQ stack.
>>> Hi Feiyang,
>>>
>>> Thanks for your patch, could you please expand how could this improve
>>> the performance?
>>>
>> Hi, Jiaxun,
>>
>> We always restore all registers in handle_sys in the v1 of the
>> patchset. Since regs->regs[27] is marked where we need to restore all
>> registers, now we simply use it as the return value of do_syscall to
>> determine whether we can only restore partial registers in handle_sys.
> can people, who provided performance numbers for v1 do the same for v2 ?


Sure, I will test the v2 in the next few days.


Thanks and best regards!


>
> Thomas,
>

^ permalink raw reply	[flat|nested] 13+ messages in thread

* Re: [PATCH v2 0/2] MIPS: convert to generic entry
  2021-09-21 15:57     ` Thomas Bogendoerfer
  2021-09-23 14:33       ` Zhou Yanjie
@ 2021-09-23 23:51       ` Jiaxun Yang
  1 sibling, 0 replies; 13+ messages in thread
From: Jiaxun Yang @ 2021-09-23 23:51 UTC (permalink / raw)
  To: Thomas Bogendoerfer, FreeFlyingSheep
  Cc: Thomas Gleixner, peterz, luto, Arnd Bergmann, Feiyang Chen,
	linux-mips, linux-arch, Huacai Chen, Zhou Yanjie,
	H. Nikolaus Schaller



在2021年9月21日九月 下午4:57,Thomas Bogendoerfer写道:
>
> can people, who provided performance numbers for v1 do the same for v2 ?

Sorry I just move abroad (to UK) to seek higher education. Currently I don't have any MIPS device available so I won't be able to provide test results as v1.

I'll try to get some MIPS devices soonish.

Thanks.

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

-- 
- Jiaxun

^ permalink raw reply	[flat|nested] 13+ messages in thread

* Re: [PATCH v2 0/2] MIPS: convert to generic entry
  2021-09-23 14:33       ` Zhou Yanjie
@ 2021-10-13 15:00         ` Zhou Yanjie
  2021-10-18 19:32           ` Maciej W. Rozycki
  0 siblings, 1 reply; 13+ messages in thread
From: Zhou Yanjie @ 2021-10-13 15:00 UTC (permalink / raw)
  To: Thomas Bogendoerfer, Feiyang Chen
  Cc: Jiaxun Yang, tglx, peterz, luto, arnd, Feiyang Chen, linux-mips,
	linux-arch, chenhuacai, H. Nikolaus Schaller

Hi Thomas,

On 2021/9/23 下午10:33, Zhou Yanjie wrote:
> Hi Thomas,
>
> On 2021/9/21 下午11:57, Thomas Bogendoerfer wrote:
>> On Tue, Sep 14, 2021 at 05:30:14PM +0800, Feiyang Chen wrote:
>>> On Tue, 14 Sept 2021 at 16:54, Jiaxun Yang <jiaxun.yang@flygoat.com> 
>>> wrote:
>>>>
>>>>
>>>> 在 2021/9/14 2:50, Feiyang Chen 写道:
>>>>> Convert MIPS to use the generic entry infrastructure from
>>>>> kernel/entry/*.
>>>>>
>>>>> v2: Use regs->regs[27] to mark whether to restore all registers in
>>>>> handle_sys and enable IRQ stack.
>>>> Hi Feiyang,
>>>>
>>>> Thanks for your patch, could you please expand how could this improve
>>>> the performance?
>>>>
>>> Hi, Jiaxun,
>>>
>>> We always restore all registers in handle_sys in the v1 of the
>>> patchset. Since regs->regs[27] is marked where we need to restore all
>>> registers, now we simply use it as the return value of do_syscall to
>>> determine whether we can only restore partial registers in handle_sys.
>> can people, who provided performance numbers for v1 do the same for v2 ?
>
>
> Sure, I will test the v2 in the next few days.


Sorry for the delay, It took a lot of time to migrate the environment to 
my new computer, here is the results:


Score Without Patches  Score With Patches  Performance Change SoC Model
        105.9                102.1              -3.6%  JZ4775
        132.4                124.1              -6.3%  JZ4780(SMP off)
        170.2                155.7             -8.5%  JZ4780(SMP on)
        101.3                 91.5              -9.7%  X1000E
        187.1                179.4              -4.1%  X1830
        324.9                314.3              -3.3%  X2000(SMT off)
        394.6                373.9              -5.2%  X2000(SMT off)


Compared with the V1 version, there are some improvements, but the 
performance loss is still a bit obvious

Thanks and best regards!


>
>
> Thanks and best regards!
>
>
>>
>> Thomas,
>>

^ permalink raw reply	[flat|nested] 13+ messages in thread

* Re: [PATCH v2 0/2] MIPS: convert to generic entry
  2021-10-13 15:00         ` Zhou Yanjie
@ 2021-10-18 19:32           ` Maciej W. Rozycki
  2021-10-19  2:22             ` Feiyang Chen
  0 siblings, 1 reply; 13+ messages in thread
From: Maciej W. Rozycki @ 2021-10-18 19:32 UTC (permalink / raw)
  To: Zhou Yanjie
  Cc: Thomas Bogendoerfer, Feiyang Chen, Jiaxun Yang, tglx, peterz,
	luto, arnd, Feiyang Chen, linux-mips, linux-arch, chenhuacai,
	H. Nikolaus Schaller

On Wed, 13 Oct 2021, Zhou Yanjie wrote:

> > > can people, who provided performance numbers for v1 do the same for v2 ?
> > 
> > 
> > Sure, I will test the v2 in the next few days.
> 
> 
> Sorry for the delay, It took a lot of time to migrate the environment to my
> new computer, here is the results:
> 
> 
> Score Without Patches  Score With Patches  Performance Change SoC Model
>        105.9                102.1              -3.6%  JZ4775
>        132.4                124.1              -6.3%  JZ4780(SMP off)
>        170.2                155.7             -8.5%  JZ4780(SMP on)
>        101.3                 91.5              -9.7%  X1000E
>        187.1                179.4              -4.1%  X1830
>        324.9                314.3              -3.3%  X2000(SMT off)
>        394.6                373.9              -5.2%  X2000(SMT off)
> 
> 
> Compared with the V1 version, there are some improvements, but the performance
> loss is still a bit obvious

 The MIPS port of Linux has always had the pride of having a particularly 
low syscall overhead and I'd rather we didn't lose this quality.

 FWIW,

  Maciej

^ permalink raw reply	[flat|nested] 13+ messages in thread

* Re: [PATCH v2 0/2] MIPS: convert to generic entry
  2021-10-18 19:32           ` Maciej W. Rozycki
@ 2021-10-19  2:22             ` Feiyang Chen
  2021-10-19  8:33               ` Maciej W. Rozycki
  0 siblings, 1 reply; 13+ messages in thread
From: Feiyang Chen @ 2021-10-19  2:22 UTC (permalink / raw)
  To: Maciej W. Rozycki
  Cc: Zhou Yanjie, Thomas Bogendoerfer, Jiaxun Yang, tglx, peterz,
	luto, arnd, Feiyang Chen, linux-mips, linux-arch, chenhuacai,
	H. Nikolaus Schaller

On Tue, 19 Oct 2021 at 03:32, Maciej W. Rozycki <macro@orcam.me.uk> wrote:
>
> On Wed, 13 Oct 2021, Zhou Yanjie wrote:
>
> > > > can people, who provided performance numbers for v1 do the same for v2 ?
> > >
> > >
> > > Sure, I will test the v2 in the next few days.
> >
> >
> > Sorry for the delay, It took a lot of time to migrate the environment to my
> > new computer, here is the results:
> >
> >
> > Score Without Patches  Score With Patches  Performance Change SoC Model
> >        105.9                102.1              -3.6%  JZ4775
> >        132.4                124.1              -6.3%  JZ4780(SMP off)
> >        170.2                155.7             -8.5%  JZ4780(SMP on)
> >        101.3                 91.5              -9.7%  X1000E
> >        187.1                179.4              -4.1%  X1830
> >        324.9                314.3              -3.3%  X2000(SMT off)
> >        394.6                373.9              -5.2%  X2000(SMT off)
> >
> >
> > Compared with the V1 version, there are some improvements, but the performance
> > loss is still a bit obvious
>
>  The MIPS port of Linux has always had the pride of having a particularly
> low syscall overhead and I'd rather we didn't lose this quality.

Hi, Maciej,

1. The current trend is to use generic code, so I think this work is
worth it, even if there is some performance loss.
2. We tested the performance on 5.15-rc1~rc5 and the performance
loss on JZ4780 (SMP off) is not so obvious (about -3%).
3. Yanjie, is there any problem with the code base you tested?
Could you help to test patch v3 on the latest mainline kernel?

Thanks,
Feiyang

>
>  FWIW,
>
>   Maciej

^ permalink raw reply	[flat|nested] 13+ messages in thread

* Re: [PATCH v2 0/2] MIPS: convert to generic entry
  2021-10-19  2:22             ` Feiyang Chen
@ 2021-10-19  8:33               ` Maciej W. Rozycki
  2021-10-22  2:19                 ` Feiyang Chen
  0 siblings, 1 reply; 13+ messages in thread
From: Maciej W. Rozycki @ 2021-10-19  8:33 UTC (permalink / raw)
  To: Feiyang Chen
  Cc: Zhou Yanjie, Thomas Bogendoerfer, Jiaxun Yang, tglx, peterz,
	luto, arnd, Feiyang Chen, linux-mips, linux-arch, chenhuacai,
	H. Nikolaus Schaller

On Tue, 19 Oct 2021, Feiyang Chen wrote:

> > > Score Without Patches  Score With Patches  Performance Change SoC Model
> > >        105.9                102.1              -3.6%  JZ4775
> > >        132.4                124.1              -6.3%  JZ4780(SMP off)
> > >        170.2                155.7             -8.5%  JZ4780(SMP on)
> > >        101.3                 91.5              -9.7%  X1000E
> > >        187.1                179.4              -4.1%  X1830
> > >        324.9                314.3              -3.3%  X2000(SMT off)
> > >        394.6                373.9              -5.2%  X2000(SMT off)
> > >
> > >
> > > Compared with the V1 version, there are some improvements, but the performance
> > > loss is still a bit obvious
> >
> >  The MIPS port of Linux has always had the pride of having a particularly
> > low syscall overhead and I'd rather we didn't lose this quality.
> 
> Hi, Maciej,
> 
> 1. The current trend is to use generic code, so I think this work is
> worth it, even if there is some performance loss.

 Well, a trend is not a proper justification on its own for existing code, 
and mature one for that matter, that works.  Surely it might be for an 
entirely new port, but the MIPS port is not exactly one.

> 2. We tested the performance on 5.15-rc1~rc5 and the performance
> loss on JZ4780 (SMP off) is not so obvious (about -3%).

 I've seen teams work hard to improve performance by less than 3%, so 
depending on how you look at it the loss is not necessarily small, even if 
not abysmal.  And I find the figure of almost 10% cited for another system 
even more worrisome.  Also you've written the figures are from UnixBench, 
which I suppose measures some kind of an average across various workloads.  
Can you elaborate on the methodology used by that benchmark?

 Can you tell me what the performance loss is for a cheap syscall such as 
`getuid'?  That would indicate how much is actually lost in the invocation 
overhead.

 With that amount known, would you be able to indicate where exactly the 
performance is getting lost in generic code?  Can it be improved?

  Maciej

^ permalink raw reply	[flat|nested] 13+ messages in thread

* Re: [PATCH v2 0/2] MIPS: convert to generic entry
  2021-10-19  8:33               ` Maciej W. Rozycki
@ 2021-10-22  2:19                 ` Feiyang Chen
  0 siblings, 0 replies; 13+ messages in thread
From: Feiyang Chen @ 2021-10-22  2:19 UTC (permalink / raw)
  To: Maciej W. Rozycki
  Cc: Zhou Yanjie, Thomas Bogendoerfer, Jiaxun Yang, tglx, peterz,
	luto, arnd, Feiyang Chen, linux-mips, linux-arch, chenhuacai,
	H. Nikolaus Schaller

On Tue, 19 Oct 2021 at 16:33, Maciej W. Rozycki <macro@orcam.me.uk> wrote:
>
> On Tue, 19 Oct 2021, Feiyang Chen wrote:
>
> > > > Score Without Patches  Score With Patches  Performance Change SoC Model
> > > >        105.9                102.1              -3.6%  JZ4775
> > > >        132.4                124.1              -6.3%  JZ4780(SMP off)
> > > >        170.2                155.7             -8.5%  JZ4780(SMP on)
> > > >        101.3                 91.5              -9.7%  X1000E
> > > >        187.1                179.4              -4.1%  X1830
> > > >        324.9                314.3              -3.3%  X2000(SMT off)
> > > >        394.6                373.9              -5.2%  X2000(SMT off)
> > > >
> > > >
> > > > Compared with the V1 version, there are some improvements, but the performance
> > > > loss is still a bit obvious
> > >
> > >  The MIPS port of Linux has always had the pride of having a particularly
> > > low syscall overhead and I'd rather we didn't lose this quality.
> >
> > Hi, Maciej,
> >
> > 1. The current trend is to use generic code, so I think this work is
> > worth it, even if there is some performance loss.
>
>  Well, a trend is not a proper justification on its own for existing code,
> and mature one for that matter, that works.  Surely it might be for an
> entirely new port, but the MIPS port is not exactly one.
>
> > 2. We tested the performance on 5.15-rc1~rc5 and the performance
> > loss on JZ4780 (SMP off) is not so obvious (about -3%).
>
>  I've seen teams work hard to improve performance by less than 3%, so
> depending on how you look at it the loss is not necessarily small, even if
> not abysmal.  And I find the figure of almost 10% cited for another system
> even more worrisome.  Also you've written the figures are from UnixBench,
> which I suppose measures some kind of an average across various workloads.
> Can you elaborate on the methodology used by that benchmark?

Hi, Maciej,

UnixBench uses multiple tests to test various aspects of the system's
performance:

- Dhrystone test measures the speed and efficiency of non-floating-point
  operations.
- Whetstone test measures the speed and efficiency of floating-point
  operations.
- execl Throughput test measures the number of execl() calls that can be
  performed per second.
- File Copy test measures the rate at which data can be transferred from one
  file to another, using various buffer sizes.
- Pipe Throughput test measures the number of times (per second) a process
  can write 512 bytes to a pipe and read them back.
- Pipe-based Context Switching test measures the number of times two
  processes can exchange an increasing integer through a pipe.
- Process Creation test measures the number of times a process can fork and
  reap a child that immediately exits.
- Shell Scripts test measures the number of times per minute a process can
  start and reap a set of one, two, four and eight concurrent copies of a
  shell script where the shell script applies a series of transformations
  to a data file.
- System Call Overhead test measures the cost of entering and leaving the
  operating system kernel.

In these tests above, the most affected is the System Call Overhead test,
and I'll go into more detail about how it's measured.

The System Call Overhead test counts the sets of system calls that are
completed within the specified time (usually 10 seconds). By default, a set
of system calls contain close(), getpid(), getuid(), and umask(). We call
the test score "index". Specifically, the score for this test is calculated
as follows:

product = log(count) - log(time / timebase)
result = exp(product / iterations)
index = result / baseline * 10

"timebase" and "baseline" are fixed values that are different for each test.
Scores for other tests are calculated in a similar way. The final total
score is calculated as follows (The total number of tests is "N"):

index = exp((log(result1) + log(result2) + ... + log(resultN)) / N) * 10

>
>  Can you tell me what the performance loss is for a cheap syscall such as
> `getuid'?  That would indicate how much is actually lost in the invocation
> overhead.

We use perf to measure the sys time of the the following program on Loongson
3A4000:

int main(void)
{
    for (int i = 0; i < 10000000; i++)
        getuid();
    return 0;
}

The program will take about 1.2 seconds of sys time before the kernel is
patched, and about 1.3 seconds after the kernel is patched.

>
>  With that amount known, would you be able to indicate where exactly the
> performance is getting lost in generic code?  Can it be improved?

Sorry, we tried to use perf to analyze the extra time, but have no idea at
the moment, since most of the code is located in __noinstr_text_start.

Thanks,
Feiyang

>
>   Maciej

^ permalink raw reply	[flat|nested] 13+ messages in thread

end of thread, other threads:[~2021-10-22  2:19 UTC | newest]

Thread overview: 13+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-09-14  1:50 [PATCH v2 0/2] MIPS: convert to generic entry Feiyang Chen
2021-09-14  1:50 ` [PATCH v2 1/2] MIPS: convert syscall " Feiyang Chen
2021-09-14  1:50 ` [PATCH v2 2/2] MIPS: convert irq " Feiyang Chen
2021-09-14  8:54 ` [PATCH v2 0/2] MIPS: convert " Jiaxun Yang
2021-09-14  9:30   ` Feiyang Chen
2021-09-21 15:57     ` Thomas Bogendoerfer
2021-09-23 14:33       ` Zhou Yanjie
2021-10-13 15:00         ` Zhou Yanjie
2021-10-18 19:32           ` Maciej W. Rozycki
2021-10-19  2:22             ` Feiyang Chen
2021-10-19  8:33               ` Maciej W. Rozycki
2021-10-22  2:19                 ` Feiyang Chen
2021-09-23 23:51       ` Jiaxun Yang

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