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| author | Thomas Gleixner <tglx@linutronix.de> | 2021-02-10 00:40:43 +0100 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2021-02-10 23:34:13 +0100 |
| commit | e7f89001797148e8dc7060c335df2c56e73a8c7a (patch) | |
| tree | 6fd44fa30593a4d513f47aa7c1c80d4f3ec588ab /arch/x86/include/asm/processor.h | |
| parent | 15f720aabe71a5662c4198b22532d95bbeec80ef (diff) | |
| download | lwn-e7f89001797148e8dc7060c335df2c56e73a8c7a.tar.gz lwn-e7f89001797148e8dc7060c335df2c56e73a8c7a.zip | |
x86/irq: Sanitize irq stack tracking
The recursion protection for hard interrupt stacks is an unsigned int per
CPU variable initialized to -1 named __irq_count.
The irq stack switching is only done when the variable is -1, which creates
worse code than just checking for 0. When the stack switching happens it
uses this_cpu_add/sub(1), but there is no reason to do so. It simply can
use straight writes. This is a historical leftover from the low level ASM
code which used inc and jz to make a decision.
Rename it to hardirq_stack_inuse, make it a bool and use plain stores.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20210210002512.228830141@linutronix.de
Diffstat (limited to 'arch/x86/include/asm/processor.h')
| -rw-r--r-- | arch/x86/include/asm/processor.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h index c20a52b5534b..11d10f4f3059 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -454,7 +454,7 @@ static inline unsigned long cpu_kernelmode_gs_base(int cpu) return (unsigned long)per_cpu(fixed_percpu_data.gs_base, cpu); } -DECLARE_PER_CPU(unsigned int, irq_count); +DECLARE_PER_CPU(bool, hardirq_stack_inuse); extern asmlinkage void ignore_sysret(void); /* Save actual FS/GS selectors and bases to current->thread */ |