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| author | Alexander Kuleshov <kuleshovmail@gmail.com> | 2016-11-28 10:50:57 +0300 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2017-02-04 11:36:59 +0300 |
| commit | 07d495dae20717b00881798ef812f7aa53ca0eb3 (patch) | |
| tree | 1971fa9711049b5f90653cfc9fc940722466f50f /arch/x86 | |
| parent | 68dee8e2f2cacc54d038394e70d22411dee89da2 (diff) | |
| download | linux-07d495dae20717b00881798ef812f7aa53ca0eb3.tar.xz | |
x86/traps: Get rid of unnecessary preempt_disable/preempt_enable_no_resched
Exception handlers which may run on IST stack call ist_enter() at the start
of execution and ist_exit() in the end. ist_enter() disables preemption
unconditionally and ist_exit() enables it.
So the extra preempt_disable/enable() pairs nested inside the
ist_enter/exit() regions are pointless and can be removed.
Signed-off-by: Alexander Kuleshov <kuleshovmail@gmail.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Jianyu Zhan <nasa4836@gmail.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@suse.de>
Link: http://lkml.kernel.org/r/20161128075057.7724-1-kuleshovmail@gmail.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/kernel/traps.c | 5 |
1 files changed, 0 insertions, 5 deletions
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index bf0c6d049080..1dc86ee60a03 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -563,11 +563,9 @@ dotraplinkage void notrace do_int3(struct pt_regs *regs, long error_code) * as we may switch to the interrupt stack. */ debug_stack_usage_inc(); - preempt_disable(); cond_local_irq_enable(regs); do_trap(X86_TRAP_BP, SIGTRAP, "int3", regs, error_code, NULL); cond_local_irq_disable(regs); - preempt_enable_no_resched(); debug_stack_usage_dec(); exit: ist_exit(regs); @@ -742,14 +740,12 @@ dotraplinkage void do_debug(struct pt_regs *regs, long error_code) debug_stack_usage_inc(); /* It's safe to allow irq's after DR6 has been saved */ - preempt_disable(); cond_local_irq_enable(regs); if (v8086_mode(regs)) { handle_vm86_trap((struct kernel_vm86_regs *) regs, error_code, X86_TRAP_DB); cond_local_irq_disable(regs); - preempt_enable_no_resched(); debug_stack_usage_dec(); goto exit; } @@ -769,7 +765,6 @@ dotraplinkage void do_debug(struct pt_regs *regs, long error_code) if (tsk->thread.debugreg6 & (DR_STEP | DR_TRAP_BITS) || user_icebp) send_sigtrap(tsk, regs, error_code, si_code); cond_local_irq_disable(regs); - preempt_enable_no_resched(); debug_stack_usage_dec(); exit: |