[PATCH v6 1/2] powerpc/syscall: Do not check unsupported scv vector on PPC32
From: Christophe Leroy <hidden>
Date: 2021-02-09 23:11:45
Also in:
lkml
Subsystem:
linux for powerpc (32-bit and 64-bit), ptrace support, the rest · Maintainers:
Madhavan Srinivasan, Oleg Nesterov, Linus Torvalds
Only book3s/64 has scv. No need to check the 0x7ff0 trap on 32 or 64e. For that, add a helper trap_is_unsupported_scv() similar to trap_is_scv(). And ignore the scv parameter in syscall_exit_prepare (Save 14 cycles 346 => 332 cycles) Signed-off-by: Christophe Leroy <redacted> --- v5: Added a helper trap_is_unsupported_scv() v6: Still set r5 when calling syscall_exit_prepare() and introduce a local bool 'is_not_scv' --- arch/powerpc/include/asm/ptrace.h | 5 +++++ arch/powerpc/kernel/interrupt.c | 9 +++++---- 2 files changed, 10 insertions(+), 4 deletions(-)
diff --git a/arch/powerpc/include/asm/ptrace.h b/arch/powerpc/include/asm/ptrace.h
index 8236c5e749e4..975ba260006a 100644
--- a/arch/powerpc/include/asm/ptrace.h
+++ b/arch/powerpc/include/asm/ptrace.h@@ -232,6 +232,11 @@ static inline bool trap_is_scv(struct pt_regs *regs) return (IS_ENABLED(CONFIG_PPC_BOOK3S_64) && TRAP(regs) == 0x3000); } +static inline bool trap_is_unsupported_scv(struct pt_regs *regs) +{ + return IS_ENABLED(CONFIG_PPC_BOOK3S_64) && TRAP(regs) == 0x7ff0; +} + static inline bool trap_is_syscall(struct pt_regs *regs) { return (trap_is_scv(regs) || TRAP(regs) == 0xc00);
diff --git a/arch/powerpc/kernel/interrupt.c b/arch/powerpc/kernel/interrupt.c
index 107ec39f05cb..75d657b63332 100644
--- a/arch/powerpc/kernel/interrupt.c
+++ b/arch/powerpc/kernel/interrupt.c@@ -88,7 +88,7 @@ notrace long system_call_exception(long r3, long r4, long r5, local_irq_enable(); if (unlikely(current_thread_info()->flags & _TIF_SYSCALL_DOTRACE)) { - if (unlikely(regs->trap == 0x7ff0)) { + if (unlikely(trap_is_unsupported_scv(regs))) { /* Unsupported scv vector */ _exception(SIGILL, regs, ILL_ILLOPC, regs->nip); return regs->gpr[3];
@@ -111,7 +111,7 @@ notrace long system_call_exception(long r3, long r4, long r5, r8 = regs->gpr[8]; } else if (unlikely(r0 >= NR_syscalls)) { - if (unlikely(regs->trap == 0x7ff0)) { + if (unlikely(trap_is_unsupported_scv(regs))) { /* Unsupported scv vector */ _exception(SIGILL, regs, ILL_ILLOPC, regs->nip); return regs->gpr[3];
@@ -220,6 +220,7 @@ notrace unsigned long syscall_exit_prepare(unsigned long r3, unsigned long *ti_flagsp = ¤t_thread_info()->flags; unsigned long ti_flags; unsigned long ret = 0; + bool is_not_scv = !IS_ENABLED(CONFIG_PPC_BOOK3S_64) || !scv; CT_WARN_ON(ct_state() == CONTEXT_USER);
@@ -234,7 +235,7 @@ notrace unsigned long syscall_exit_prepare(unsigned long r3, ti_flags = *ti_flagsp; - if (unlikely(r3 >= (unsigned long)-MAX_ERRNO) && !scv) { + if (unlikely(r3 >= (unsigned long)-MAX_ERRNO) && is_not_scv) { if (likely(!(ti_flags & (_TIF_NOERROR | _TIF_RESTOREALL)))) { r3 = -r3; regs->ccr |= 0x10000000; /* Set SO bit in CR */
@@ -305,7 +306,7 @@ notrace unsigned long syscall_exit_prepare(unsigned long r3, user_enter_irqoff(); /* scv need not set RI=0 because SRRs are not used */ - if (unlikely(!__prep_irq_for_enabled_exit(!scv))) { + if (unlikely(!__prep_irq_for_enabled_exit(is_not_scv))) { user_exit_irqoff(); local_irq_enable(); local_irq_disable();
--
2.25.0