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authorWill Deacon <will@kernel.org>2019-07-30 17:40:20 +0300
committerCatalin Marinas <catalin.marinas@arm.com>2019-07-31 20:10:55 +0300
commit147b9635e6347104b91f48ca9dca61eb0fbf2a54 (patch)
treeb353ced3427563d2135282afda8d350fcb1208bb /arch
parenta22c5cf5d37ddcd4d2dd98ee9cf04fa5dd1e1c01 (diff)
downloadlinux-147b9635e6347104b91f48ca9dca61eb0fbf2a54.tar.xz
arm64: cpufeature: Fix feature comparison for CTR_EL0.{CWG,ERG}
If CTR_EL0.{CWG,ERG} are 0b0000 then they must be interpreted to have their architecturally maximum values, which defeats the use of FTR_HIGHER_SAFE when sanitising CPU ID registers on heterogeneous machines. Introduce FTR_HIGHER_OR_ZERO_SAFE so that these fields effectively saturate at zero. Fixes: 3c739b571084 ("arm64: Keep track of CPU feature registers") Cc: <stable@vger.kernel.org> # 4.4.x- Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> Acked-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch')
-rw-r--r--arch/arm64/include/asm/cpufeature.h7
-rw-r--r--arch/arm64/kernel/cpufeature.c8
2 files changed, 10 insertions, 5 deletions
diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h
index 407e2bf23676..c96ffa4722d3 100644
--- a/arch/arm64/include/asm/cpufeature.h
+++ b/arch/arm64/include/asm/cpufeature.h
@@ -35,9 +35,10 @@
*/
enum ftr_type {
- FTR_EXACT, /* Use a predefined safe value */
- FTR_LOWER_SAFE, /* Smaller value is safe */
- FTR_HIGHER_SAFE,/* Bigger value is safe */
+ FTR_EXACT, /* Use a predefined safe value */
+ FTR_LOWER_SAFE, /* Smaller value is safe */
+ FTR_HIGHER_SAFE, /* Bigger value is safe */
+ FTR_HIGHER_OR_ZERO_SAFE, /* Bigger value is safe, but 0 is biggest */
};
#define FTR_STRICT true /* SANITY check strict matching required */
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index f29f36a65175..d19d14ba9ae4 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -225,8 +225,8 @@ static const struct arm64_ftr_bits ftr_ctr[] = {
ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_EXACT, 31, 1, 1), /* RES1 */
ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, CTR_DIC_SHIFT, 1, 1),
ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, CTR_IDC_SHIFT, 1, 1),
- ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_HIGHER_SAFE, CTR_CWG_SHIFT, 4, 0),
- ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_HIGHER_SAFE, CTR_ERG_SHIFT, 4, 0),
+ ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_HIGHER_OR_ZERO_SAFE, CTR_CWG_SHIFT, 4, 0),
+ ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_HIGHER_OR_ZERO_SAFE, CTR_ERG_SHIFT, 4, 0),
ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, CTR_DMINLINE_SHIFT, 4, 1),
/*
* Linux can handle differing I-cache policies. Userspace JITs will
@@ -468,6 +468,10 @@ static s64 arm64_ftr_safe_value(const struct arm64_ftr_bits *ftrp, s64 new,
case FTR_LOWER_SAFE:
ret = new < cur ? new : cur;
break;
+ case FTR_HIGHER_OR_ZERO_SAFE:
+ if (!cur || !new)
+ break;
+ /* Fallthrough */
case FTR_HIGHER_SAFE:
ret = new > cur ? new : cur;
break;