From bd4fb6d270bc423a9a4098108784f7f9254c4e6d Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Thu, 14 Jun 2018 11:21:34 +0100 Subject: arm64: Add support for SB barrier and patch in over DSB; ISB sequences We currently use a DSB; ISB sequence to inhibit speculation in set_fs(). Whilst this works for current CPUs, future CPUs may implement a new SB barrier instruction which acts as an architected speculation barrier. On CPUs that support it, patch in an SB; NOP sequence over the DSB; ISB sequence and advertise the presence of the new instruction to userspace. Signed-off-by: Will Deacon --- arch/arm64/include/asm/cpucaps.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'arch/arm64/include/asm/cpucaps.h') diff --git a/arch/arm64/include/asm/cpucaps.h b/arch/arm64/include/asm/cpucaps.h index 6e2d254c09eb..b7f0709a21af 100644 --- a/arch/arm64/include/asm/cpucaps.h +++ b/arch/arm64/include/asm/cpucaps.h @@ -54,7 +54,8 @@ #define ARM64_HAS_CRC32 33 #define ARM64_SSBS 34 #define ARM64_WORKAROUND_1188873 35 +#define ARM64_HAS_SB 36 -#define ARM64_NCAPS 36 +#define ARM64_NCAPS 37 #endif /* __ASM_CPUCAPS_H */ -- cgit v1.2.3-70-g09d2