arm64/hwcaps: Add MTE_STORE_ONLY hwcaps

Since ARMv8.9, FEAT_MTE_STORE_ONLY can be used to restrict raise of tag
check fault on store operation only.

add MTE_STORE_ONLY hwcaps so that user can use this feature.

Signed-off-by: Yeoreum Yun <yeoreum.yun@arm.com>
Link: https://lore.kernel.org/r/20250618092957.2069907-5-yeoreum.yun@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

diff --git a/Documentation/arch/arm64/elf_hwcaps.rst b/Documentation/arch/arm64/elf_hwcaps.rst
index 358f5af035ffdd05ee27f4466422be68fdf6a680..f58ada4d6cb2fdd0bf0a68e736390d4d36effbef 100644 (file)
--- a/Documentation/arch/arm64/elf_hwcaps.rst
+++ b/Documentation/arch/arm64/elf_hwcaps.rst
@@ -438,6 +438,9 @@ HWCAP2_POE
 HWCAP3_MTE_FAR
     Functionality implied by ID_AA64PFR2_EL1.MTEFAR == 0b0001.
 
+HWCAP3_MTE_STORE_ONLY
+    Functionality implied by ID_AA64PFR2_EL1.MTESTOREONLY == 0b0001.
+
 4. Unused AT_HWCAP bits
 -----------------------
 

diff --git a/arch/arm64/include/asm/hwcap.h b/arch/arm64/include/asm/hwcap.h
index 28dd1ac29ecc84d188b56c41d46690c2c6f05a28..13f94c8ddfc03b7d453adda39dfbc47e2b5e6b9d 100644 (file)
--- a/arch/arm64/include/asm/hwcap.h
+++ b/arch/arm64/include/asm/hwcap.h
@@ -177,6 +177,7 @@
 
 #define __khwcap3_feature(x)           (const_ilog2(HWCAP3_ ## x) + 128)
 #define KERNEL_HWCAP_MTE_FAR           __khwcap3_feature(MTE_FAR)
+#define KERNEL_HWCAP_MTE_STORE_ONLY    __khwcap3_feature(MTE_STORE_ONLY)
 
 /*
  * This yields a mask that user programs can use to figure out what

diff --git a/arch/arm64/include/uapi/asm/hwcap.h b/arch/arm64/include/uapi/asm/hwcap.h
index 7d22527a7975d29b29345bfff2c71d14a484e342..72c78468b806b5400b8c487ac6af91ca3de63dbb 100644 (file)
--- a/arch/arm64/include/uapi/asm/hwcap.h
+++ b/arch/arm64/include/uapi/asm/hwcap.h
@@ -144,5 +144,6 @@
  * HWCAP3 flags - for AT_HWCAP3
  */
 #define HWCAP3_MTE_FAR         (1UL << 0)
+#define HWCAP3_MTE_STORE_ONLY          (1UL << 1)
 
 #endif /* _UAPI__ASM_HWCAP_H */

diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index fdc48aa1f0e23720c004d8cd4d082fc3ae841aae..b4204fa743f0c0716d63fa6d6b876c9c6737716b 100644 (file)
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -3228,6 +3228,7 @@ static const struct arm64_cpu_capabilities arm64_elf_hwcaps[] = {
        HWCAP_CAP(ID_AA64PFR1_EL1, MTE, MTE2, CAP_HWCAP, KERNEL_HWCAP_MTE),
        HWCAP_CAP(ID_AA64PFR1_EL1, MTE, MTE3, CAP_HWCAP, KERNEL_HWCAP_MTE3),
        HWCAP_CAP(ID_AA64PFR2_EL1, MTEFAR, IMP, CAP_HWCAP, KERNEL_HWCAP_MTE_FAR),
+       HWCAP_CAP(ID_AA64PFR2_EL1, MTESTOREONLY, IMP, CAP_HWCAP , KERNEL_HWCAP_MTE_STORE_ONLY),
 #endif /* CONFIG_ARM64_MTE */
        HWCAP_CAP(ID_AA64MMFR0_EL1, ECV, IMP, CAP_HWCAP, KERNEL_HWCAP_ECV),
        HWCAP_CAP(ID_AA64MMFR1_EL1, AFP, IMP, CAP_HWCAP, KERNEL_HWCAP_AFP),

diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c
index e552cb305641498c8e05d4bf93d84a55a938cb32..ba834909a28bd06ff5fb23a311006a32d01f3d99 100644 (file)
--- a/arch/arm64/kernel/cpuinfo.c
+++ b/arch/arm64/kernel/cpuinfo.c
@@ -161,6 +161,7 @@ static const char *const hwcap_str[] = {
        [KERNEL_HWCAP_SME_STMOP]        = "smestmop",
        [KERNEL_HWCAP_SME_SMOP4]        = "smesmop4",
        [KERNEL_HWCAP_MTE_FAR]          = "mtefar",
+       [KERNEL_HWCAP_MTE_STORE_ONLY]   = "mtestoreonly",
 };
 
 #ifdef CONFIG_COMPAT