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| author | Andy Lutomirski <luto@kernel.org> | 2015-10-06 03:48:17 +0300 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2015-10-09 10:41:11 +0300 |
| commit | 8b13c2552ffc8e54e57598df36707183933e8e8c (patch) | |
| tree | a8f9006a526818b051e1128af5ca03dd44a0e8b3 /arch/x86/entry | |
| parent | 487e3bf4f77699160aa81a414200060a78a67c3d (diff) | |
| download | linux-8b13c2552ffc8e54e57598df36707183933e8e8c.tar.xz | |
x86/entry: Remove unnecessary IRQ twiddling in fast 32-bit syscalls
This is slightly messy, but it eliminates an unnecessary cli;sti
pair.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/22f34b1096694a37326f36c53407b8dd90f37948.1444091585.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/entry')
| -rw-r--r-- | arch/x86/entry/common.c | 18 |
1 files changed, 11 insertions, 7 deletions
diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c index 0ed023d6a983..0d1c842ef3ca 100644 --- a/arch/x86/entry/common.c +++ b/arch/x86/entry/common.c @@ -323,10 +323,10 @@ __visible void syscall_return_slowpath(struct pt_regs *regs) #if defined(CONFIG_X86_32) || defined(CONFIG_IA32_EMULATION) /* - * Does a 32-bit syscall. Called with IRQs off and does all entry and - * exit work. + * Does a 32-bit syscall. Called with IRQs on and does all entry and + * exit work and returns with IRQs off. */ -__visible void do_int80_syscall_32(struct pt_regs *regs) +static void do_syscall_32_irqs_on(struct pt_regs *regs) { struct thread_info *ti = pt_regs_to_thread_info(regs); unsigned int nr = (unsigned int)regs->orig_ax; @@ -335,8 +335,6 @@ __visible void do_int80_syscall_32(struct pt_regs *regs) ti->status |= TS_COMPAT; #endif - local_irq_enable(); - if (READ_ONCE(ti->flags) & _TIF_WORK_SYSCALL_ENTRY) { /* * Subtlety here: if ptrace pokes something larger than @@ -363,6 +361,13 @@ __visible void do_int80_syscall_32(struct pt_regs *regs) syscall_return_slowpath(regs); } +/* Handles int $0x80 */ +__visible void do_int80_syscall_32(struct pt_regs *regs) +{ + local_irq_enable(); + do_syscall_32_irqs_on(regs); +} + /* Returns 0 to return using IRET or 1 to return using SYSEXIT/SYSRETL. */ __visible long do_fast_syscall_32(struct pt_regs *regs) { @@ -398,10 +403,9 @@ __visible long do_fast_syscall_32(struct pt_regs *regs) prepare_exit_to_usermode(regs); return 0; /* Keep it simple: use IRET. */ } - local_irq_disable(); /* Now this is just like a normal syscall. */ - do_int80_syscall_32(regs); + do_syscall_32_irqs_on(regs); #ifdef CONFIG_X86_64 /* |