| Message ID | 20250123-riscv_optimize_entry-v2-3-7c259492d508@rivosinc.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | entry: Move ret_from_fork() to C and inline syscall_exit_to_user_mode() | expand |
Hi, Charlie, On Fri, Jan 24, 2025 at 3:15 AM Charlie Jenkins <charlie@rivosinc.com> wrote: > > Loongarch is the only architecture that calls We usually use "LoongArch" instead of "loongarch" or "Loongarch". > syscall_exit_to_user_mode() from asm. Move the call into C so that this > function can be inlined across all architectures. > > Signed-off-by: Charlie Jenkins <charlie@rivosinc.com> > --- > arch/loongarch/include/asm/asm-prototypes.h | 5 +++++ > arch/loongarch/include/asm/switch_to.h | 8 +++++++ > arch/loongarch/kernel/entry.S | 22 +++++++++---------- > arch/loongarch/kernel/process.c | 34 ++++++++++++++++++++++++----- > 4 files changed, 51 insertions(+), 18 deletions(-) > > diff --git a/arch/loongarch/include/asm/asm-prototypes.h b/arch/loongarch/include/asm/asm-prototypes.h > index 51f224bcfc654228ae423e9a066b25b35102a5b9..0195d4309fd29f94664d5f34247198c769033b1b 100644 > --- a/arch/loongarch/include/asm/asm-prototypes.h > +++ b/arch/loongarch/include/asm/asm-prototypes.h > @@ -12,3 +12,8 @@ __int128_t __ashlti3(__int128_t a, int b); > __int128_t __ashrti3(__int128_t a, int b); > __int128_t __lshrti3(__int128_t a, int b); > #endif > + > +asmlinkage void noinstr __no_stack_protector ret_from_kernel_thread(struct task_struct *prev, > + struct pt_regs *regs, > + int (*fn)(void *), > + void *fn_arg); It is a little strange that we only need to declare ret_from_kernel_thread() but not ret_from_fork(). > diff --git a/arch/loongarch/include/asm/switch_to.h b/arch/loongarch/include/asm/switch_to.h > index 5b225aff3ba21aa06d0713bc8e73e1b941389630..a1c5576f1fd145670e13038bec6dd390486099ab 100644 > --- a/arch/loongarch/include/asm/switch_to.h > +++ b/arch/loongarch/include/asm/switch_to.h > @@ -26,6 +26,14 @@ extern asmlinkage struct task_struct *__switch_to(struct task_struct *prev, > struct task_struct *next, struct thread_info *next_ti, > void *sched_ra, void *sched_cfa); > > +void noinstr __no_stack_protector ret_from_kernel_thread(struct task_struct *prev, > + struct pt_regs *regs, > + int (*fn)(void *), > + void *fn_arg); > + > +void noinstr __no_stack_protector ret_from_fork(struct task_struct *prev, > + struct pt_regs *regs); > + I prefer alpha-betical order, which means put ret_from_fork() before ret_from_kernel_thread(). > /* > * For newly created kernel threads switch_to() will return to > * ret_from_kernel_thread, newly created user threads to ret_from_fork. > diff --git a/arch/loongarch/kernel/entry.S b/arch/loongarch/kernel/entry.S > index 48e7e34e355e83eae8165957ba2eac05a8bf17df..2abc29e573810e000f2fef4646ddca0dbb80eabe 100644 > --- a/arch/loongarch/kernel/entry.S > +++ b/arch/loongarch/kernel/entry.S > @@ -77,24 +77,22 @@ SYM_CODE_START(handle_syscall) > SYM_CODE_END(handle_syscall) > _ASM_NOKPROBE(handle_syscall) > > -SYM_CODE_START(ret_from_fork) > +SYM_CODE_START(ret_from_fork_asm) > UNWIND_HINT_REGS > - bl schedule_tail # a0 = struct task_struct *prev > - move a0, sp > - bl syscall_exit_to_user_mode > + move a1, sp > + bl ret_from_fork > RESTORE_STATIC > RESTORE_SOME > RESTORE_SP_AND_RET > -SYM_CODE_END(ret_from_fork) > +SYM_CODE_END(ret_from_fork_asm) > > -SYM_CODE_START(ret_from_kernel_thread) > +SYM_CODE_START(ret_from_kernel_thread_asm) > UNWIND_HINT_REGS > - bl schedule_tail # a0 = struct task_struct *prev > - move a0, s1 > - jirl ra, s0, 0 > - move a0, sp > - bl syscall_exit_to_user_mode > + move a1, sp > + move a2, s0 > + move a3, s1 > + bl ret_from_kernel_thread > RESTORE_STATIC > RESTORE_SOME > RESTORE_SP_AND_RET > -SYM_CODE_END(ret_from_kernel_thread) > +SYM_CODE_END(ret_from_kernel_thread_asm) > diff --git a/arch/loongarch/kernel/process.c b/arch/loongarch/kernel/process.c > index 6e58f65455c7ca3eae2e88ed852c8655a6701e5c..16cc949fe43443d70f1d865ce04595c2d8c1615b 100644 > --- a/arch/loongarch/kernel/process.c > +++ b/arch/loongarch/kernel/process.c > @@ -14,6 +14,7 @@ > #include <linux/init.h> > #include <linux/kernel.h> > #include <linux/errno.h> > +#include <linux/entry-common.h> > #include <linux/sched.h> > #include <linux/sched/debug.h> > #include <linux/sched/task.h> > @@ -33,6 +34,7 @@ > #include <linux/prctl.h> > #include <linux/nmi.h> > > +#include <asm/asm-prototypes.h> > #include <asm/asm.h> > #include <asm/bootinfo.h> > #include <asm/cpu.h> > @@ -47,6 +49,7 @@ > #include <asm/pgtable.h> > #include <asm/processor.h> > #include <asm/reg.h> > +#include <asm/switch_to.h> > #include <asm/unwind.h> > #include <asm/vdso.h> > > @@ -63,8 +66,9 @@ EXPORT_SYMBOL(__stack_chk_guard); > unsigned long boot_option_idle_override = IDLE_NO_OVERRIDE; > EXPORT_SYMBOL(boot_option_idle_override); > > -asmlinkage void ret_from_fork(void); > -asmlinkage void ret_from_kernel_thread(void); > +asmlinkage void restore_and_ret(void); > +asmlinkage void ret_from_fork_asm(void); > +asmlinkage void ret_from_kernel_thread_asm(void); > > void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long sp) > { > @@ -138,6 +142,24 @@ int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src) > return 0; > } > > +asmlinkage void noinstr __no_stack_protector ret_from_kernel_thread(struct task_struct *prev, > + struct pt_regs *regs, > + int (*fn)(void *), > + void *fn_arg) > +{ > + schedule_tail(prev); > + > + fn(fn_arg); > + The two blank lines can be removed, and again, I prefer alpha-betical order, which means put ret_from_fork() before ret_from_kernel_thread(). Huacai > + syscall_exit_to_user_mode(regs); > +} > + > +void noinstr __no_stack_protector ret_from_fork(struct task_struct *prev, struct pt_regs *regs) > +{ > + schedule_tail(prev); > + syscall_exit_to_user_mode(regs); > +} > + > /* > * Copy architecture-specific thread state > */ > @@ -165,8 +187,8 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args) > p->thread.reg03 = childksp; > p->thread.reg23 = (unsigned long)args->fn; > p->thread.reg24 = (unsigned long)args->fn_arg; > - p->thread.reg01 = (unsigned long)ret_from_kernel_thread; > - p->thread.sched_ra = (unsigned long)ret_from_kernel_thread; > + p->thread.reg01 = (unsigned long)ret_from_kernel_thread_asm; > + p->thread.sched_ra = (unsigned long)ret_from_kernel_thread_asm; > memset(childregs, 0, sizeof(struct pt_regs)); > childregs->csr_euen = p->thread.csr_euen; > childregs->csr_crmd = p->thread.csr_crmd; > @@ -182,8 +204,8 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args) > childregs->regs[3] = usp; > > p->thread.reg03 = (unsigned long) childregs; > - p->thread.reg01 = (unsigned long) ret_from_fork; > - p->thread.sched_ra = (unsigned long) ret_from_fork; > + p->thread.reg01 = (unsigned long) ret_from_fork_asm; > + p->thread.sched_ra = (unsigned long) ret_from_fork_asm; > > /* > * New tasks lose permission to use the fpu. This accelerates context > > -- > 2.43.0 >
On Fri, Jan 24, 2025 at 05:05:21PM +0800, Huacai Chen wrote: > Hi, Charlie, > > On Fri, Jan 24, 2025 at 3:15 AM Charlie Jenkins <charlie@rivosinc.com> wrote: > > > > Loongarch is the only architecture that calls > We usually use "LoongArch" instead of "loongarch" or "Loongarch". > > > syscall_exit_to_user_mode() from asm. Move the call into C so that this > > function can be inlined across all architectures. > > > > Signed-off-by: Charlie Jenkins <charlie@rivosinc.com> > > --- > > arch/loongarch/include/asm/asm-prototypes.h | 5 +++++ > > arch/loongarch/include/asm/switch_to.h | 8 +++++++ > > arch/loongarch/kernel/entry.S | 22 +++++++++---------- > > arch/loongarch/kernel/process.c | 34 ++++++++++++++++++++++++----- > > 4 files changed, 51 insertions(+), 18 deletions(-) > > > > diff --git a/arch/loongarch/include/asm/asm-prototypes.h b/arch/loongarch/include/asm/asm-prototypes.h > > index 51f224bcfc654228ae423e9a066b25b35102a5b9..0195d4309fd29f94664d5f34247198c769033b1b 100644 > > --- a/arch/loongarch/include/asm/asm-prototypes.h > > +++ b/arch/loongarch/include/asm/asm-prototypes.h > > @@ -12,3 +12,8 @@ __int128_t __ashlti3(__int128_t a, int b); > > __int128_t __ashrti3(__int128_t a, int b); > > __int128_t __lshrti3(__int128_t a, int b); > > #endif > > + > > +asmlinkage void noinstr __no_stack_protector ret_from_kernel_thread(struct task_struct *prev, > > + struct pt_regs *regs, > > + int (*fn)(void *), > > + void *fn_arg); > It is a little strange that we only need to declare > ret_from_kernel_thread() but not ret_from_fork(). Just an oversight by me, thank you for pointing that out. > > > diff --git a/arch/loongarch/include/asm/switch_to.h b/arch/loongarch/include/asm/switch_to.h > > index 5b225aff3ba21aa06d0713bc8e73e1b941389630..a1c5576f1fd145670e13038bec6dd390486099ab 100644 > > --- a/arch/loongarch/include/asm/switch_to.h > > +++ b/arch/loongarch/include/asm/switch_to.h > > @@ -26,6 +26,14 @@ extern asmlinkage struct task_struct *__switch_to(struct task_struct *prev, > > struct task_struct *next, struct thread_info *next_ti, > > void *sched_ra, void *sched_cfa); > > > > +void noinstr __no_stack_protector ret_from_kernel_thread(struct task_struct *prev, > > + struct pt_regs *regs, > > + int (*fn)(void *), > > + void *fn_arg); > > + > > +void noinstr __no_stack_protector ret_from_fork(struct task_struct *prev, > > + struct pt_regs *regs); > > + > I prefer alpha-betical order, which means put ret_from_fork() before > ret_from_kernel_thread(). Makes sense! > > > /* > > * For newly created kernel threads switch_to() will return to > > * ret_from_kernel_thread, newly created user threads to ret_from_fork. > > diff --git a/arch/loongarch/kernel/entry.S b/arch/loongarch/kernel/entry.S > > index 48e7e34e355e83eae8165957ba2eac05a8bf17df..2abc29e573810e000f2fef4646ddca0dbb80eabe 100644 > > --- a/arch/loongarch/kernel/entry.S > > +++ b/arch/loongarch/kernel/entry.S > > @@ -77,24 +77,22 @@ SYM_CODE_START(handle_syscall) > > SYM_CODE_END(handle_syscall) > > _ASM_NOKPROBE(handle_syscall) > > > > -SYM_CODE_START(ret_from_fork) > > +SYM_CODE_START(ret_from_fork_asm) > > UNWIND_HINT_REGS > > - bl schedule_tail # a0 = struct task_struct *prev > > - move a0, sp > > - bl syscall_exit_to_user_mode > > + move a1, sp > > + bl ret_from_fork > > RESTORE_STATIC > > RESTORE_SOME > > RESTORE_SP_AND_RET > > -SYM_CODE_END(ret_from_fork) > > +SYM_CODE_END(ret_from_fork_asm) > > > > -SYM_CODE_START(ret_from_kernel_thread) > > +SYM_CODE_START(ret_from_kernel_thread_asm) > > UNWIND_HINT_REGS > > - bl schedule_tail # a0 = struct task_struct *prev > > - move a0, s1 > > - jirl ra, s0, 0 > > - move a0, sp > > - bl syscall_exit_to_user_mode > > + move a1, sp > > + move a2, s0 > > + move a3, s1 > > + bl ret_from_kernel_thread > > RESTORE_STATIC > > RESTORE_SOME > > RESTORE_SP_AND_RET > > -SYM_CODE_END(ret_from_kernel_thread) > > +SYM_CODE_END(ret_from_kernel_thread_asm) > > diff --git a/arch/loongarch/kernel/process.c b/arch/loongarch/kernel/process.c > > index 6e58f65455c7ca3eae2e88ed852c8655a6701e5c..16cc949fe43443d70f1d865ce04595c2d8c1615b 100644 > > --- a/arch/loongarch/kernel/process.c > > +++ b/arch/loongarch/kernel/process.c > > @@ -14,6 +14,7 @@ > > #include <linux/init.h> > > #include <linux/kernel.h> > > #include <linux/errno.h> > > +#include <linux/entry-common.h> > > #include <linux/sched.h> > > #include <linux/sched/debug.h> > > #include <linux/sched/task.h> > > @@ -33,6 +34,7 @@ > > #include <linux/prctl.h> > > #include <linux/nmi.h> > > > > +#include <asm/asm-prototypes.h> > > #include <asm/asm.h> > > #include <asm/bootinfo.h> > > #include <asm/cpu.h> > > @@ -47,6 +49,7 @@ > > #include <asm/pgtable.h> > > #include <asm/processor.h> > > #include <asm/reg.h> > > +#include <asm/switch_to.h> > > #include <asm/unwind.h> > > #include <asm/vdso.h> > > > > @@ -63,8 +66,9 @@ EXPORT_SYMBOL(__stack_chk_guard); > > unsigned long boot_option_idle_override = IDLE_NO_OVERRIDE; > > EXPORT_SYMBOL(boot_option_idle_override); > > > > -asmlinkage void ret_from_fork(void); > > -asmlinkage void ret_from_kernel_thread(void); > > +asmlinkage void restore_and_ret(void); > > +asmlinkage void ret_from_fork_asm(void); > > +asmlinkage void ret_from_kernel_thread_asm(void); > > > > void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long sp) > > { > > @@ -138,6 +142,24 @@ int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src) > > return 0; > > } > > > > +asmlinkage void noinstr __no_stack_protector ret_from_kernel_thread(struct task_struct *prev, > > + struct pt_regs *regs, > > + int (*fn)(void *), > > + void *fn_arg) > > +{ > > + schedule_tail(prev); > > + > > + fn(fn_arg); > > + > The two blank lines can be removed, and again, I prefer alpha-betical > order, which means put ret_from_fork() before > ret_from_kernel_thread(). Will update in the next version. - Charlie > > Huacai > > > + syscall_exit_to_user_mode(regs); > > +} > > + > > +void noinstr __no_stack_protector ret_from_fork(struct task_struct *prev, struct pt_regs *regs) > > +{ > > + schedule_tail(prev); > > + syscall_exit_to_user_mode(regs); > > +} > > + > > /* > > * Copy architecture-specific thread state > > */ > > @@ -165,8 +187,8 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args) > > p->thread.reg03 = childksp; > > p->thread.reg23 = (unsigned long)args->fn; > > p->thread.reg24 = (unsigned long)args->fn_arg; > > - p->thread.reg01 = (unsigned long)ret_from_kernel_thread; > > - p->thread.sched_ra = (unsigned long)ret_from_kernel_thread; > > + p->thread.reg01 = (unsigned long)ret_from_kernel_thread_asm; > > + p->thread.sched_ra = (unsigned long)ret_from_kernel_thread_asm; > > memset(childregs, 0, sizeof(struct pt_regs)); > > childregs->csr_euen = p->thread.csr_euen; > > childregs->csr_crmd = p->thread.csr_crmd; > > @@ -182,8 +204,8 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args) > > childregs->regs[3] = usp; > > > > p->thread.reg03 = (unsigned long) childregs; > > - p->thread.reg01 = (unsigned long) ret_from_fork; > > - p->thread.sched_ra = (unsigned long) ret_from_fork; > > + p->thread.reg01 = (unsigned long) ret_from_fork_asm; > > + p->thread.sched_ra = (unsigned long) ret_from_fork_asm; > > > > /* > > * New tasks lose permission to use the fpu. This accelerates context > > > > -- > > 2.43.0 > >
On Fri, Jan 24, 2025 at 10:28:50AM -0800, Charlie Jenkins wrote: > On Fri, Jan 24, 2025 at 05:05:21PM +0800, Huacai Chen wrote: > > Hi, Charlie, > > > > On Fri, Jan 24, 2025 at 3:15 AM Charlie Jenkins <charlie@rivosinc.com> wrote: > > > > > > Loongarch is the only architecture that calls > > We usually use "LoongArch" instead of "loongarch" or "Loongarch". > > > > > syscall_exit_to_user_mode() from asm. Move the call into C so that this > > > function can be inlined across all architectures. > > > > > > Signed-off-by: Charlie Jenkins <charlie@rivosinc.com> > > > --- > > > arch/loongarch/include/asm/asm-prototypes.h | 5 +++++ > > > arch/loongarch/include/asm/switch_to.h | 8 +++++++ > > > arch/loongarch/kernel/entry.S | 22 +++++++++---------- > > > arch/loongarch/kernel/process.c | 34 ++++++++++++++++++++++++----- > > > 4 files changed, 51 insertions(+), 18 deletions(-) > > > > > > diff --git a/arch/loongarch/include/asm/asm-prototypes.h b/arch/loongarch/include/asm/asm-prototypes.h > > > index 51f224bcfc654228ae423e9a066b25b35102a5b9..0195d4309fd29f94664d5f34247198c769033b1b 100644 > > > --- a/arch/loongarch/include/asm/asm-prototypes.h > > > +++ b/arch/loongarch/include/asm/asm-prototypes.h > > > @@ -12,3 +12,8 @@ __int128_t __ashlti3(__int128_t a, int b); > > > __int128_t __ashrti3(__int128_t a, int b); > > > __int128_t __lshrti3(__int128_t a, int b); > > > #endif > > > + > > > +asmlinkage void noinstr __no_stack_protector ret_from_kernel_thread(struct task_struct *prev, > > > + struct pt_regs *regs, > > > + int (*fn)(void *), > > > + void *fn_arg); > > It is a little strange that we only need to declare > > ret_from_kernel_thread() but not ret_from_fork(). > > Just an oversight by me, thank you for pointing that out. Oh I see what I did, I meant to put these functions in asm-prototypes and not in switch_to but I ended up putting them in both. - Charlie
diff --git a/arch/loongarch/include/asm/asm-prototypes.h b/arch/loongarch/include/asm/asm-prototypes.h index 51f224bcfc654228ae423e9a066b25b35102a5b9..0195d4309fd29f94664d5f34247198c769033b1b 100644 --- a/arch/loongarch/include/asm/asm-prototypes.h +++ b/arch/loongarch/include/asm/asm-prototypes.h @@ -12,3 +12,8 @@ __int128_t __ashlti3(__int128_t a, int b); __int128_t __ashrti3(__int128_t a, int b); __int128_t __lshrti3(__int128_t a, int b); #endif + +asmlinkage void noinstr __no_stack_protector ret_from_kernel_thread(struct task_struct *prev, + struct pt_regs *regs, + int (*fn)(void *), + void *fn_arg); diff --git a/arch/loongarch/include/asm/switch_to.h b/arch/loongarch/include/asm/switch_to.h index 5b225aff3ba21aa06d0713bc8e73e1b941389630..a1c5576f1fd145670e13038bec6dd390486099ab 100644 --- a/arch/loongarch/include/asm/switch_to.h +++ b/arch/loongarch/include/asm/switch_to.h @@ -26,6 +26,14 @@ extern asmlinkage struct task_struct *__switch_to(struct task_struct *prev, struct task_struct *next, struct thread_info *next_ti, void *sched_ra, void *sched_cfa); +void noinstr __no_stack_protector ret_from_kernel_thread(struct task_struct *prev, + struct pt_regs *regs, + int (*fn)(void *), + void *fn_arg); + +void noinstr __no_stack_protector ret_from_fork(struct task_struct *prev, + struct pt_regs *regs); + /* * For newly created kernel threads switch_to() will return to * ret_from_kernel_thread, newly created user threads to ret_from_fork. diff --git a/arch/loongarch/kernel/entry.S b/arch/loongarch/kernel/entry.S index 48e7e34e355e83eae8165957ba2eac05a8bf17df..2abc29e573810e000f2fef4646ddca0dbb80eabe 100644 --- a/arch/loongarch/kernel/entry.S +++ b/arch/loongarch/kernel/entry.S @@ -77,24 +77,22 @@ SYM_CODE_START(handle_syscall) SYM_CODE_END(handle_syscall) _ASM_NOKPROBE(handle_syscall) -SYM_CODE_START(ret_from_fork) +SYM_CODE_START(ret_from_fork_asm) UNWIND_HINT_REGS - bl schedule_tail # a0 = struct task_struct *prev - move a0, sp - bl syscall_exit_to_user_mode + move a1, sp + bl ret_from_fork RESTORE_STATIC RESTORE_SOME RESTORE_SP_AND_RET -SYM_CODE_END(ret_from_fork) +SYM_CODE_END(ret_from_fork_asm) -SYM_CODE_START(ret_from_kernel_thread) +SYM_CODE_START(ret_from_kernel_thread_asm) UNWIND_HINT_REGS - bl schedule_tail # a0 = struct task_struct *prev - move a0, s1 - jirl ra, s0, 0 - move a0, sp - bl syscall_exit_to_user_mode + move a1, sp + move a2, s0 + move a3, s1 + bl ret_from_kernel_thread RESTORE_STATIC RESTORE_SOME RESTORE_SP_AND_RET -SYM_CODE_END(ret_from_kernel_thread) +SYM_CODE_END(ret_from_kernel_thread_asm) diff --git a/arch/loongarch/kernel/process.c b/arch/loongarch/kernel/process.c index 6e58f65455c7ca3eae2e88ed852c8655a6701e5c..16cc949fe43443d70f1d865ce04595c2d8c1615b 100644 --- a/arch/loongarch/kernel/process.c +++ b/arch/loongarch/kernel/process.c @@ -14,6 +14,7 @@ #include <linux/init.h> #include <linux/kernel.h> #include <linux/errno.h> +#include <linux/entry-common.h> #include <linux/sched.h> #include <linux/sched/debug.h> #include <linux/sched/task.h> @@ -33,6 +34,7 @@ #include <linux/prctl.h> #include <linux/nmi.h> +#include <asm/asm-prototypes.h> #include <asm/asm.h> #include <asm/bootinfo.h> #include <asm/cpu.h> @@ -47,6 +49,7 @@ #include <asm/pgtable.h> #include <asm/processor.h> #include <asm/reg.h> +#include <asm/switch_to.h> #include <asm/unwind.h> #include <asm/vdso.h> @@ -63,8 +66,9 @@ EXPORT_SYMBOL(__stack_chk_guard); unsigned long boot_option_idle_override = IDLE_NO_OVERRIDE; EXPORT_SYMBOL(boot_option_idle_override); -asmlinkage void ret_from_fork(void); -asmlinkage void ret_from_kernel_thread(void); +asmlinkage void restore_and_ret(void); +asmlinkage void ret_from_fork_asm(void); +asmlinkage void ret_from_kernel_thread_asm(void); void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long sp) { @@ -138,6 +142,24 @@ int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src) return 0; } +asmlinkage void noinstr __no_stack_protector ret_from_kernel_thread(struct task_struct *prev, + struct pt_regs *regs, + int (*fn)(void *), + void *fn_arg) +{ + schedule_tail(prev); + + fn(fn_arg); + + syscall_exit_to_user_mode(regs); +} + +void noinstr __no_stack_protector ret_from_fork(struct task_struct *prev, struct pt_regs *regs) +{ + schedule_tail(prev); + syscall_exit_to_user_mode(regs); +} + /* * Copy architecture-specific thread state */ @@ -165,8 +187,8 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args) p->thread.reg03 = childksp; p->thread.reg23 = (unsigned long)args->fn; p->thread.reg24 = (unsigned long)args->fn_arg; - p->thread.reg01 = (unsigned long)ret_from_kernel_thread; - p->thread.sched_ra = (unsigned long)ret_from_kernel_thread; + p->thread.reg01 = (unsigned long)ret_from_kernel_thread_asm; + p->thread.sched_ra = (unsigned long)ret_from_kernel_thread_asm; memset(childregs, 0, sizeof(struct pt_regs)); childregs->csr_euen = p->thread.csr_euen; childregs->csr_crmd = p->thread.csr_crmd; @@ -182,8 +204,8 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args) childregs->regs[3] = usp; p->thread.reg03 = (unsigned long) childregs; - p->thread.reg01 = (unsigned long) ret_from_fork; - p->thread.sched_ra = (unsigned long) ret_from_fork; + p->thread.reg01 = (unsigned long) ret_from_fork_asm; + p->thread.sched_ra = (unsigned long) ret_from_fork_asm; /* * New tasks lose permission to use the fpu. This accelerates context
Loongarch is the only architecture that calls syscall_exit_to_user_mode() from asm. Move the call into C so that this function can be inlined across all architectures. Signed-off-by: Charlie Jenkins <charlie@rivosinc.com> --- arch/loongarch/include/asm/asm-prototypes.h | 5 +++++ arch/loongarch/include/asm/switch_to.h | 8 +++++++ arch/loongarch/kernel/entry.S | 22 +++++++++---------- arch/loongarch/kernel/process.c | 34 ++++++++++++++++++++++++----- 4 files changed, 51 insertions(+), 18 deletions(-)