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authorJulien Grall <julien.grall@arm.com>2019-10-14 13:21:13 +0300
committerWill Deacon <will@kernel.org>2019-10-15 03:56:57 +0300
commitec52c7134b1fcef0edfc56d55072fd4f261ef198 (patch)
treed5c3cffad34849de6ff23ff92dd53ed3386093f6 /arch/arm64
parent86109a691a454e08cbe0356400268cb2a81f1997 (diff)
downloadlinux-ec52c7134b1fcef0edfc56d55072fd4f261ef198.tar.xz
arm64: cpufeature: Treat ID_AA64ZFR0_EL1 as RAZ when SVE is not enabled
If CONFIG_ARM64_SVE=n then we fail to report ID_AA64ZFR0_EL1 as 0 when read by userspace, despite being required by the architecture. Although this is theoretically a change in ABI, userspace will first check for the presence of SVE via the HWCAP or the ID_AA64PFR0_EL1.SVE field before probing the ID_AA64ZFR0_EL1 register. Given that these are reported correctly for this configuration, we can safely tighten up the current behaviour. Ensure ID_AA64ZFR0_EL1 is treated as RAZ when CONFIG_ARM64_SVE=n. Signed-off-by: Julien Grall <julien.grall@arm.com> Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> Reviewed-by: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Dave Martin <dave.martin@arm.com> Fixes: 06a916feca2b ("arm64: Expose SVE2 features for userspace") Signed-off-by: Will Deacon <will@kernel.org>
Diffstat (limited to 'arch/arm64')
-rw-r--r--arch/arm64/kernel/cpufeature.c15
1 files changed, 10 insertions, 5 deletions
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index cabebf1a7976..80f459ad0190 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -176,11 +176,16 @@ static const struct arm64_ftr_bits ftr_id_aa64pfr1[] = {
};
static const struct arm64_ftr_bits ftr_id_aa64zfr0[] = {
- ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ZFR0_SM4_SHIFT, 4, 0),
- ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ZFR0_SHA3_SHIFT, 4, 0),
- ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ZFR0_BITPERM_SHIFT, 4, 0),
- ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ZFR0_AES_SHIFT, 4, 0),
- ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ZFR0_SVEVER_SHIFT, 4, 0),
+ ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SVE),
+ FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ZFR0_SM4_SHIFT, 4, 0),
+ ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SVE),
+ FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ZFR0_SHA3_SHIFT, 4, 0),
+ ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SVE),
+ FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ZFR0_BITPERM_SHIFT, 4, 0),
+ ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SVE),
+ FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ZFR0_AES_SHIFT, 4, 0),
+ ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SVE),
+ FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ZFR0_SVEVER_SHIFT, 4, 0),
ARM64_FTR_END,
};