Michal Suchánek's on August 29, 2019 1:30 am:
> 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);
Thanks I didn't see that.
> uapi/asm/ptrace.h defines user_pt_regs and asm/ptrace.h pt_regs.
>
> I am not really sure which you wanted.
pt_regs. That is the struct that gets saved on the kernel stack by
interrupts. user_pt_regs is part of the ptrace user ABI.
Thanks,
Nick
