Re: [PATCH 1/2] mips: convert syscall to generic entry

[Jiaxun Yang <jiaxun.yang@flygoat.com>]

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

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

I guess it's worthy?

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

For the code,

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

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

Thanks.

Jiaxun

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