diff options
| author | Russell King <rmk+kernel@armlinux.org.uk> | 2018-05-11 15:06:58 +0100 |
|---|---|---|
| committer | Russell King <rmk+kernel@armlinux.org.uk> | 2018-05-31 23:27:21 +0100 |
| commit | 1d4238c56f9816ce0f9c8dbe42d7f2ad81cb6613 (patch) | |
| tree | 02ce63e527d19829f5f0059b1cea00897da1469a /arch/arm | |
| parent | a78d156587931a2c3b354534aa772febf6c9e855 (diff) | |
ARM: spectre-v1: add array_index_mask_nospec() implementation
Add an implementation of the array_index_mask_nospec() function for
mitigating Spectre variant 1 throughout the kernel.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Boot-tested-by: Tony Lindgren <tony@atomide.com>
Reviewed-by: Tony Lindgren <tony@atomide.com>
Diffstat (limited to 'arch/arm')
| -rw-r--r-- | arch/arm/include/asm/barrier.h | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/arch/arm/include/asm/barrier.h b/arch/arm/include/asm/barrier.h index 3d9c1d4b7e75..69772e742a0a 100644 --- a/arch/arm/include/asm/barrier.h +++ b/arch/arm/include/asm/barrier.h @@ -76,6 +76,25 @@ extern void arm_heavy_mb(void); #define __smp_rmb() __smp_mb() #define __smp_wmb() dmb(ishst) +#ifdef CONFIG_CPU_SPECTRE +static inline unsigned long array_index_mask_nospec(unsigned long idx, + unsigned long sz) +{ + unsigned long mask; + + asm volatile( + "cmp %1, %2\n" + " sbc %0, %1, %1\n" + CSDB + : "=r" (mask) + : "r" (idx), "Ir" (sz) + : "cc"); + + return mask; +} +#define array_index_mask_nospec array_index_mask_nospec +#endif + #include <asm-generic/barrier.h> #endif /* !__ASSEMBLY__ */ |