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From: "Nicholas Piggin" <npiggin@gmail.com>
To: "Rohan McLure" <rmclure@linux.ibm.com>, <linuxppc-dev@lists.ozlabs.org>
Subject: Re: [PATCH v6 20/25] powerpc: Change system_call_exception calling convention
Date: Fri, 23 Sep 2022 17:43:33 +1000	[thread overview]
Message-ID: <CN3M2A0W1J3A.2V3NYEDYLSIVQ@bobo> (raw)
In-Reply-To: <20220921065605.1051927-21-rmclure@linux.ibm.com>

On Wed Sep 21, 2022 at 4:56 PM AEST, Rohan McLure wrote:
> Change system_call_exception arguments to pass a pointer to a stack frame
> container caller state, as well as the original r0, which determines the
> number of the syscall. This has been observed to yield improved performance
> to passing them by registers, circumventing the need to allocate a stack frame.
>
> Signed-off-by: Rohan McLure <rmclure@linux.ibm.com>

Thanks for splitting it out, I think it does make it nicer to review.

[...]

> diff --git a/arch/powerpc/kernel/syscall.c b/arch/powerpc/kernel/syscall.c
> index 15af0ed019a7..0e9ba3efee94 100644
> --- a/arch/powerpc/kernel/syscall.c
> +++ b/arch/powerpc/kernel/syscall.c
> @@ -13,9 +13,7 @@
>  
>  
>  /* Has to run notrace because it is entered not completely "reconciled" */
> -notrace long system_call_exception(long r3, long r4, long r5,
> -				   long r6, long r7, long r8,
> -				   unsigned long r0, struct pt_regs *regs)
> +notrace long system_call_exception(struct pt_regs *regs, unsigned long r0)
>  {
>  	long ret;
>  	syscall_fn f;
> @@ -136,12 +134,6 @@ notrace long system_call_exception(long r3, long r4, long r5,
>  		r0 = do_syscall_trace_enter(regs);
>  		if (unlikely(r0 >= NR_syscalls))
>  			return regs->gpr[3];
> -		r3 = regs->gpr[3];
> -		r4 = regs->gpr[4];
> -		r5 = regs->gpr[5];
> -		r6 = regs->gpr[6];
> -		r7 = regs->gpr[7];
> -		r8 = regs->gpr[8];
>  
>  	} else if (unlikely(r0 >= NR_syscalls)) {
>  		if (unlikely(trap_is_unsupported_scv(regs))) {
> -- 
> 2.34.1

This is probably just missing the hunk

+       ret = f(regs->gpr[3], regs->gpr[4], regs->gpr[5],                                                                                                                                                                              
+               regs->gpr[6], regs->gpr[7], regs->gpr[8]);        

which got into your next patch.

Otherwise I think it looks good.

Reviewed-by: Nicholas Piggin <npiggin@gmail.com>

  reply	other threads:[~2022-09-23  7:44 UTC|newest]

Thread overview: 49+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-21  6:55 [PATCH v6 00/25] powerpc: Syscall wrapper and register clearing Rohan McLure
2022-09-21  6:55 ` [PATCH v6 01/25] powerpc: Remove asmlinkage from syscall handler definitions Rohan McLure
2022-09-21  6:55 ` [PATCH v6 02/25] powerpc: Save caller r3 prior to system_call_exception Rohan McLure
2022-09-21  6:55 ` [PATCH v6 03/25] powerpc: Add ZEROIZE_GPRS macros for register clears Rohan McLure
2022-09-21  6:55 ` [PATCH v6 04/25] powerpc/64s: Use {ZEROIZE,SAVE,REST}_GPRS macros in sc, scv 0 handlers Rohan McLure
2022-09-21  6:55 ` [PATCH v6 05/25] powerpc/32: Clarify interrupt restores with REST_GPR macro in entry_32.S Rohan McLure
2022-09-21  6:55 ` [PATCH v6 06/25] powerpc/64e: Clarify register saves and clears with {SAVE,ZEROIZE}_GPRS Rohan McLure
2022-09-21  6:55 ` [PATCH v6 07/25] powerpc/64s: Fix comment on interrupt handler prologue Rohan McLure
2022-09-21  6:55 ` [PATCH v6 08/25] powerpc: Fix fallocate and fadvise64_64 compat parameter combination Rohan McLure
2022-09-21  6:55 ` [PATCH v6 09/25] asm-generic: compat: Support BE for long long args in 32-bit ABIs Rohan McLure
2022-10-31 13:23   ` [PATCH] asm-generic: compat: fix compat_arg_u64 and compat_arg_u64_dual Andreas Schwab
2022-11-01 12:25     ` Michael Ellerman
2022-11-03  8:20     ` Christophe Leroy
2022-11-03  8:48       ` Arnd Bergmann
2022-09-21  6:55 ` [PATCH v6 10/25] powerpc: Use generic fallocate compatibility syscall Rohan McLure
2022-09-21  6:55 ` [PATCH v6 11/25] powerpc/32: Remove powerpc select specialisation Rohan McLure
2022-09-21  6:55 ` [PATCH v6 12/25] powerpc: Remove direct call to personality syscall handler Rohan McLure
2022-09-21  6:55 ` [PATCH v6 13/25] powerpc: Remove direct call to mmap2 syscall handlers Rohan McLure
2022-09-28 12:15   ` Michael Ellerman
2022-09-28 13:00     ` Arnd Bergmann
2022-09-30 13:19       ` Michael Ellerman
2022-09-30 14:09         ` Arnd Bergmann
2022-09-21  6:55 ` [PATCH v6 14/25] powerpc: Provide do_ppc64_personality helper Rohan McLure
2022-09-21  6:55 ` [PATCH v6 15/25] powerpc: Adopt SYSCALL_DEFINE for arch-specific syscall handlers Rohan McLure
2022-09-21  6:55 ` [PATCH v6 16/25] powerpc: Include all arch-specific syscall prototypes Rohan McLure
2022-09-21  6:55 ` [PATCH v6 17/25] powerpc: Enable compile-time check for syscall handlers Rohan McLure
2022-09-21  6:55 ` [PATCH v6 18/25] powerpc: Use common syscall handler type Rohan McLure
2022-09-21  6:55 ` [PATCH v6 19/25] powerpc: Remove high-order word clearing on compat syscall entry Rohan McLure
2022-09-23  7:40   ` Nicholas Piggin
2022-09-28 11:56   ` Michael Ellerman
2022-09-21  6:56 ` [PATCH v6 20/25] powerpc: Change system_call_exception calling convention Rohan McLure
2022-09-23  7:43   ` Nicholas Piggin [this message]
2022-09-21  6:56 ` [PATCH v6 21/25] powerpc: Provide syscall wrapper Rohan McLure
2022-09-23  7:50   ` Nicholas Piggin
2022-10-30 15:34   ` Andreas Schwab
2022-10-30 15:50     ` Andreas Schwab
2022-10-30 19:43     ` Arnd Bergmann
2022-10-30 20:05       ` Andreas Schwab
2022-10-31  3:09         ` Michael Ellerman
2022-10-31 14:47   ` [PATCH] powerpc/32: fix syscall wrappers with 64-bit arguments Andreas Schwab
2022-10-31 19:37     ` Arnd Bergmann
2022-11-01 12:25     ` Michael Ellerman
2022-09-21  6:56 ` [PATCH v6 22/25] powerpc/64s: Clear user GPRs in syscall interrupt entry Rohan McLure
2022-09-23  8:02   ` Nicholas Piggin
2022-10-31 23:22     ` Rohan McLure
2022-09-21  6:56 ` [PATCH v6 23/25] powerpc/64: Add INTERRUPT_SANITIZE_REGISTERS Kconfig Rohan McLure
2022-09-21  6:56 ` [PATCH v6 24/25] powerpc/64s: Clear gprs on interrupt routine entry in Book3S Rohan McLure
2022-09-21  6:56 ` [PATCH v6 25/25] powerpc/64e: Clear gprs on interrupt routine entry on Book3E Rohan McLure
2022-10-04 13:24 ` [PATCH v6 00/25] powerpc: Syscall wrapper and register clearing Michael Ellerman

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