[PATCH v4 20/23] powerpc/syscall: Do not check unsupported scv vector on PPC32
From: Christophe Leroy <hidden>
Date: 2021-01-25 15:05:40
Also in:
lkml
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Michael Ellerman, Linus Torvalds
Only PPC64 has scv. No need to check the 0x7ff0 trap on PPC32. And ignore the scv parameter in syscall_exit_prepare (Save 14 cycles 346 => 332 cycles) Signed-off-by: Christophe Leroy <redacted> --- arch/powerpc/kernel/entry_32.S | 1 - arch/powerpc/kernel/syscall.c | 7 +++++-- 2 files changed, 5 insertions(+), 3 deletions(-)
diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S
index 9922a04650f7..6ae9c7bcb06c 100644
--- a/arch/powerpc/kernel/entry_32.S
+++ b/arch/powerpc/kernel/entry_32.S@@ -343,7 +343,6 @@ transfer_to_syscall: ret_from_syscall: addi r4,r1,STACK_FRAME_OVERHEAD - li r5,0 bl syscall_exit_prepare #if defined(CONFIG_4xx) || defined(CONFIG_BOOKE) /* If the process has its own DBCR0 value, load it up. The internal
diff --git a/arch/powerpc/kernel/syscall.c b/arch/powerpc/kernel/syscall.c
index 476909b11051..30f8a397a522 100644
--- a/arch/powerpc/kernel/syscall.c
+++ b/arch/powerpc/kernel/syscall.c@@ -86,7 +86,7 @@ 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 (IS_ENABLED(CONFIG_PPC64) && unlikely(regs->trap == 0x7ff0)) { /* Unsupported scv vector */ _exception(SIGILL, regs, ILL_ILLOPC, regs->nip); return regs->gpr[3];
@@ -109,7 +109,7 @@ 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 (IS_ENABLED(CONFIG_PPC64) && unlikely(regs->trap == 0x7ff0)) { /* Unsupported scv vector */ _exception(SIGILL, regs, ILL_ILLOPC, regs->nip); return regs->gpr[3];
@@ -187,6 +187,9 @@ notrace unsigned long syscall_exit_prepare(unsigned long r3, unsigned long ti_flags; unsigned long ret = 0; + if (IS_ENABLED(CONFIG_PPC32)) + scv = 0; + CT_WARN_ON(ct_state() == CONTEXT_USER); kuap_check();
--
2.25.0