The patch titled
Subject: arm64: mte: CPU feature detection for Asymm MTE
has been added to the -mm tree. Its filename is
arm64-mte-cpu-feature-detection-for-asymm-mte.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/arm64-mte-cpu-feature-detection-for-asymm-mte.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/arm64-mte-cpu-feature-detection-for-asymm-mte.patch
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------------------------------------------------------
From: Vincenzo Frascino <vincenzo.frascino@xxxxxxx>
Subject: arm64: mte: CPU feature detection for Asymm MTE
Add the cpufeature entries to detect the presence of Asymmetric MTE.
Note: The tag checking mode is initialized via cpu_enable_mte() ->
kasan_init_hw_tags() hence to enable it we require asymmetric mode to be
at least on the boot CPU. If the boot CPU does not have it, it is fine
for late CPUs to have it as long as the feature is not enabled
(ARM64_CPUCAP_BOOT_CPU_FEATURE).
Link: https://lkml.kernel.org/r/20211004202253.27857-4-vincenzo.frascino@xxxxxxx
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@xxxxxxx>
Reviewed-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Andrey Konovalov <andreyknvl@xxxxxxxxx>
Cc: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
Cc: Branislav Rankov <branislav.rankov@xxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Evgenii Stepanov <eugenis@xxxxxxxxxx>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
Cc: Marco Elver <elver@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/arm64/kernel/cpufeature.c | 10 ++++++++++
arch/arm64/tools/cpucaps | 1 +
2 files changed, 11 insertions(+)
--- a/arch/arm64/kernel/cpufeature.c~arm64-mte-cpu-feature-detection-for-asymm-mte
+++ a/arch/arm64/kernel/cpufeature.c
@@ -2321,6 +2321,16 @@ static const struct arm64_cpu_capabiliti
.sign = FTR_UNSIGNED,
.cpu_enable = cpu_enable_mte,
},
+ {
+ .desc = "Asymmetric MTE Tag Check Fault",
+ .capability = ARM64_MTE_ASYMM,
+ .type = ARM64_CPUCAP_BOOT_CPU_FEATURE,
+ .matches = has_cpuid_feature,
+ .sys_reg = SYS_ID_AA64PFR1_EL1,
+ .field_pos = ID_AA64PFR1_MTE_SHIFT,
+ .min_field_value = ID_AA64PFR1_MTE_ASYMM,
+ .sign = FTR_UNSIGNED,
+ },
#endif /* CONFIG_ARM64_MTE */
{
.desc = "RCpc load-acquire (LDAPR)",
--- a/arch/arm64/tools/cpucaps~arm64-mte-cpu-feature-detection-for-asymm-mte
+++ a/arch/arm64/tools/cpucaps
@@ -39,6 +39,7 @@ HW_DBM
KVM_PROTECTED_MODE
MISMATCHED_CACHE_TYPE
MTE
+MTE_ASYMM
SPECTRE_V2
SPECTRE_V3A
SPECTRE_V4
_
Patches currently in -mm which might be from vincenzo.frascino@xxxxxxx are
kasan-remove-duplicate-of-kasan_flag_async.patch
arm64-mte-bitfield-definitions-for-asymm-mte.patch
arm64-mte-cpu-feature-detection-for-asymm-mte.patch
arm64-mte-add-asymmetric-mode-support.patch
kasan-extend-kasan-mode-kernel-parameter.patch
