From: Rohan McLure <rmclure@linux.ibm.com>
To: linuxppc-dev@lists.ozlabs.org
Cc: Rohan McLure <rmclure@linux.ibm.com>
Subject: [PATCH v6 20/25] powerpc: Change system_call_exception calling convention
Date: Wed, 21 Sep 2022 16:56:00 +1000 [thread overview]
Message-ID: <20220921065605.1051927-21-rmclure@linux.ibm.com> (raw)
In-Reply-To: <20220921065605.1051927-1-rmclure@linux.ibm.com>
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>
---
V6: Split off from syscall wrapper patch.
---
arch/powerpc/include/asm/interrupt.h | 3 +--
arch/powerpc/kernel/entry_32.S | 6 +++---
arch/powerpc/kernel/interrupt_64.S | 20 ++++++++++----------
arch/powerpc/kernel/syscall.c | 10 +---------
4 files changed, 15 insertions(+), 24 deletions(-)
diff --git a/arch/powerpc/include/asm/interrupt.h b/arch/powerpc/include/asm/interrupt.h
index 8069dbc4b8d1..48eec9cd1429 100644
--- a/arch/powerpc/include/asm/interrupt.h
+++ b/arch/powerpc/include/asm/interrupt.h
@@ -665,8 +665,7 @@ static inline void interrupt_cond_local_irq_enable(struct pt_regs *regs)
local_irq_enable();
}
-long system_call_exception(long r3, long r4, long r5, long r6, long r7, long r8,
- unsigned long r0, struct pt_regs *regs);
+long system_call_exception(struct pt_regs *regs, unsigned long r0);
notrace unsigned long syscall_exit_prepare(unsigned long r3, struct pt_regs *regs, long scv);
notrace unsigned long interrupt_exit_user_prepare(struct pt_regs *regs);
notrace unsigned long interrupt_exit_kernel_prepare(struct pt_regs *regs);
diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S
index e4b694cebc44..96782aa72083 100644
--- a/arch/powerpc/kernel/entry_32.S
+++ b/arch/powerpc/kernel/entry_32.S
@@ -122,9 +122,9 @@ transfer_to_syscall:
SAVE_NVGPRS(r1)
kuep_lock
- /* Calling convention has r9 = orig r0, r10 = regs */
- addi r10,r1,STACK_FRAME_OVERHEAD
- mr r9,r0
+ /* Calling convention has r3 = regs, r4 = orig r0 */
+ addi r3,r1,STACK_FRAME_OVERHEAD
+ mr r4,r0
bl system_call_exception
ret_from_syscall:
diff --git a/arch/powerpc/kernel/interrupt_64.S b/arch/powerpc/kernel/interrupt_64.S
index 7d92a7a54727..a5dd78bdbe6d 100644
--- a/arch/powerpc/kernel/interrupt_64.S
+++ b/arch/powerpc/kernel/interrupt_64.S
@@ -70,7 +70,7 @@ _ASM_NOKPROBE_SYMBOL(system_call_vectored_\name)
ld r2,PACATOC(r13)
mfcr r12
li r11,0
- /* Can we avoid saving r3-r8 in common case? */
+ /* Save syscall parameters in r3-r8 */
SAVE_GPRS(3, 8, r1)
/* Zero r9-r12, this should only be required when restoring all GPRs */
std r11,GPR9(r1)
@@ -87,9 +87,11 @@ _ASM_NOKPROBE_SYMBOL(system_call_vectored_\name)
std r11,_TRAP(r1)
std r12,_CCR(r1)
std r3,ORIG_GPR3(r1)
- addi r10,r1,STACK_FRAME_OVERHEAD
+ /* Calling convention has r3 = regs, r4 = orig r0 */
+ addi r3,r1,STACK_FRAME_OVERHEAD
+ mr r4,r0
ld r11,exception_marker@toc(r2)
- std r11,-16(r10) /* "regshere" marker */
+ std r11,-16(r3) /* "regshere" marker */
BEGIN_FTR_SECTION
HMT_MEDIUM
@@ -104,8 +106,6 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
* but this is the best we can do.
*/
- /* Calling convention has r9 = orig r0, r10 = regs */
- mr r9,r0
bl system_call_exception
.Lsyscall_vectored_\name\()_exit:
@@ -237,7 +237,7 @@ END_BTB_FLUSH_SECTION
ld r2,PACATOC(r13)
mfcr r12
li r11,0
- /* Can we avoid saving r3-r8 in common case? */
+ /* Save syscall parameters in r3-r8 */
SAVE_GPRS(3, 8, r1)
/* Zero r9-r12, this should only be required when restoring all GPRs */
std r11,GPR9(r1)
@@ -260,9 +260,11 @@ END_BTB_FLUSH_SECTION
std r11,_TRAP(r1)
std r12,_CCR(r1)
std r3,ORIG_GPR3(r1)
- addi r10,r1,STACK_FRAME_OVERHEAD
+ /* Calling convention has r3 = regs, r4 = orig r0 */
+ addi r3,r1,STACK_FRAME_OVERHEAD
+ mr r4,r0
ld r11,exception_marker@toc(r2)
- std r11,-16(r10) /* "regshere" marker */
+ std r11,-16(r3) /* "regshere" marker */
#ifdef CONFIG_PPC_BOOK3S
li r11,1
@@ -283,8 +285,6 @@ END_BTB_FLUSH_SECTION
wrteei 1
#endif
- /* Calling convention has r9 = orig r0, r10 = regs */
- mr r9,r0
bl system_call_exception
.Lsyscall_exit:
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
next prev parent reply other threads:[~2022-09-21 7:10 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 ` Rohan McLure [this message]
2022-09-23 7:43 ` [PATCH v6 20/25] powerpc: Change system_call_exception calling convention Nicholas Piggin
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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