On Tue, 27 Aug 2019 23:55:48 +1000
Nicholas Piggin <npig...@gmail.com> wrote:
> System call entry and particularly exit code is beyond the limit of what
> is reasonable to implement in asm.
>
> This conversion moves all conditional branches out of the asm code,
> except for the case that all GPRs should be restored at exit.
>
> Null syscall test is about 5% faster after this patch, because the exit
> work is handled under local_irq_disable, and the hard mask and pending
> interrupt replay is handled after that, which avoids games with MSR.
>
> Signed-off-by: Nicholas Piggin <npig...@gmail.com>
> ---
> Changes since v1:
> - Improve changelog
> - Lot of code cleanups, moving helpers out to proper header locations,
> etc (Christophe).
> - Split unnecessary change that affected ppc32 out. I will submit it
> independently (Christophe).
>
> arch/powerpc/include/asm/asm-prototypes.h | 11 -
> .../powerpc/include/asm/book3s/64/kup-radix.h | 12 +-
> arch/powerpc/include/asm/cputime.h | 22 ++
> arch/powerpc/include/asm/ptrace.h | 3 +
> arch/powerpc/include/asm/signal.h | 2 +
> arch/powerpc/include/asm/switch_to.h | 5 +
> arch/powerpc/include/asm/time.h | 3 +
> arch/powerpc/kernel/Makefile | 3 +-
> arch/powerpc/kernel/entry_64.S | 340 +++---------------
> arch/powerpc/kernel/signal.h | 2 -
> arch/powerpc/kernel/syscall_64.c | 177 +++++++++
> 11 files changed, 273 insertions(+), 307 deletions(-)
> create mode 100644 arch/powerpc/kernel/syscall_64.c
>
> diff --git a/arch/powerpc/include/asm/asm-prototypes.h
> b/arch/powerpc/include/asm/asm-prototypes.h
> index ec1c97a8e8cb..f00ef8924a99 100644
> --- a/arch/powerpc/include/asm/asm-prototypes.h
> +++ b/arch/powerpc/include/asm/asm-prototypes.h
> @@ -92,14 +92,6 @@ long sys_switch_endian(void);
> notrace unsigned int __check_irq_replay(void);
> void notrace restore_interrupts(void);
>
> -/* ptrace */
> -long do_syscall_trace_enter(struct pt_regs *regs);
> -void do_syscall_trace_leave(struct pt_regs *regs);
> -
> -/* process */
> -void restore_math(struct pt_regs *regs);
> -void restore_tm_state(struct pt_regs *regs);
> -
> /* prom_init (OpenFirmware) */
> unsigned long __init prom_init(unsigned long r3, unsigned long r4,
> unsigned long pp,
> @@ -110,9 +102,6 @@ unsigned long __init prom_init(unsigned long r3, unsigned
> long r4,
> void __init early_setup(unsigned long dt_ptr);
> void early_setup_secondary(void);
>
> -/* time */
> -void accumulate_stolen_time(void);
> -
> /* misc runtime */
> extern u64 __bswapdi2(u64);
> extern s64 __lshrdi3(s64, int);
> diff --git a/arch/powerpc/include/asm/book3s/64/kup-radix.h
> b/arch/powerpc/include/asm/book3s/64/kup-radix.h
> index f254de956d6a..ef2e65ea8a73 100644
> --- a/arch/powerpc/include/asm/book3s/64/kup-radix.h
> +++ b/arch/powerpc/include/asm/book3s/64/kup-radix.h
> @@ -3,6 +3,7 @@
> #define _ASM_POWERPC_BOOK3S_64_KUP_RADIX_H
>
> #include <linux/const.h>
> +#include <asm/reg.h>
>
> #define AMR_KUAP_BLOCK_READ UL(0x4000000000000000)
> #define AMR_KUAP_BLOCK_WRITE UL(0x8000000000000000)
> @@ -56,7 +57,16 @@
>
> #ifdef CONFIG_PPC_KUAP
>
> -#include <asm/reg.h>
> +#include <asm/mmu.h>
> +#include <asm/ptrace.h>
> +
> +static inline void kuap_check_amr(void)
> +{
> +#ifdef CONFIG_PPC_KUAP_DEBUG
> + if (mmu_has_feature(MMU_FTR_RADIX_KUAP))
> + WARN_ON_ONCE(mfspr(SPRN_AMR) != AMR_KUAP_BLOCKED);
> +#endif
> +}
>
> /*
> * We support individually allowing read or write, but we don't support
> nesting
> diff --git a/arch/powerpc/include/asm/cputime.h
> b/arch/powerpc/include/asm/cputime.h
> index 2431b4ada2fa..f3aa9db1a3cc 100644
> --- a/arch/powerpc/include/asm/cputime.h
> +++ b/arch/powerpc/include/asm/cputime.h
> @@ -60,6 +60,28 @@ static inline void arch_vtime_task_switch(struct
> task_struct *prev)
> }
> #endif
>
> +static inline void account_cpu_user_entry(void)
> +{
> + unsigned long tb = mftb();
> +
> + get_accounting(current)->utime += (tb -
> get_accounting(current)->starttime_user);
> + get_accounting(current)->starttime = tb;
> +}
> +static inline void account_cpu_user_exit(void)
> +{
> + unsigned long tb = mftb();
> +
> + get_accounting(current)->stime += (tb -
> get_accounting(current)->starttime);
> + get_accounting(current)->starttime_user = tb;
> +}
> +
> #endif /* __KERNEL__ */
> +#else /* CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */
> +static inline void account_cpu_user_entry(void)
> +{
> +}
> +static inline void account_cpu_user_exit(void)
> +{
> +}
> #endif /* CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */
> #endif /* __POWERPC_CPUTIME_H */
> diff --git a/arch/powerpc/include/asm/ptrace.h
> b/arch/powerpc/include/asm/ptrace.h
> index feee1b21bbd5..af363086403a 100644
> --- a/arch/powerpc/include/asm/ptrace.h
> +++ b/arch/powerpc/include/asm/ptrace.h
> @@ -138,6 +138,9 @@ extern unsigned long profile_pc(struct pt_regs *regs);
> #define profile_pc(regs) instruction_pointer(regs)
> #endif
>
> +long do_syscall_trace_enter(struct pt_regs *regs);
> +void do_syscall_trace_leave(struct pt_regs *regs);
> +
> #define kernel_stack_pointer(regs) ((regs)->gpr[1])
> static inline int is_syscall_success(struct pt_regs *regs)
> {
> diff --git a/arch/powerpc/include/asm/signal.h
> b/arch/powerpc/include/asm/signal.h
> index 0803ca8b9149..0113be8dcb59 100644
> --- a/arch/powerpc/include/asm/signal.h
> +++ b/arch/powerpc/include/asm/signal.h
> @@ -6,4 +6,6 @@
> #include <uapi/asm/signal.h>
> #include <uapi/asm/ptrace.h>
>
> +void do_notify_resume(struct pt_regs *regs, unsigned long thread_info_flags);
> +
/srv/kernel/arch/powerpc/include/asm/signal.h:9:30: warning: ‘struct pt_regs’
declared inside parameter list will not be visible outside of this definition
or declaration
void do_notify_resume(struct pt_regs *regs, unsigned long thread_info_flags);
uapi/asm/ptrace.h defines user_pt_regs and asm/ptrace.h pt_regs.
I am not really sure which you wanted.
Thanks
Michal
