linux-kernel - [PATCH v4 4/7] arm64/hwcaps: add MTE_STORE

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20250507154654.1937588-5-yeoreum.yun@arm.com>
Date: Wed,  7 May 2025 16:46:51 +0100
From: Yeoreum Yun <yeoreum.yun@....com>
To: catalin.marinas@....com,
	pcc@...gle.com,
	will@...nel.org,
	broonie@...nel.org,
	anshuman.khandual@....com,
	joey.gouly@....com,
	maz@...nel.org,
	oliver.upton@...ux.dev,
	frederic@...nel.org,
	james.morse@....com,
	hardevsinh.palaniya@...iconsignals.io,
	huangxiaojia2@...wei.com,
	mark.rutland@....com,
	samuel.holland@...ive.com,
	palmer@...osinc.com,
	charlie@...osinc.com,
	thiago.bauermann@...aro.org,
	bgray@...ux.ibm.com,
	tglx@...utronix.de,
	puranjay@...nel.org,
	david@...hat.com,
	yang@...amperecomputing.com,
	mbenes@...e.cz,
	joel.granados@...nel.org
Cc: linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org,
	Yeoreum Yun <yeoreum.yun@....com>
Subject: [PATCH v4 4/7] 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@....com>
---
 Documentation/arch/arm64/elf_hwcaps.rst | 3 +++
 arch/arm64/include/asm/hwcap.h          | 1 +
 arch/arm64/include/uapi/asm/hwcap.h     | 1 +
 arch/arm64/kernel/cpufeature.c          | 1 +
 arch/arm64/kernel/cpuinfo.c             | 1 +
 5 files changed, 7 insertions(+)

diff --git a/Documentation/arch/arm64/elf_hwcaps.rst b/Documentation/arch/arm64/elf_hwcaps.rst
index 358f5af035ff..f58ada4d6cb2 100644
--- 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 28dd1ac29ecc..13f94c8ddfc0 100644
--- 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 7d22527a7975..72c78468b806 100644
--- 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 de42f890bcd7..a2f25a8bed96 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -3208,6 +3208,7 @@ 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 058e21295003..37fd9a56b0ce 100644
--- 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
-- 
LEVI:{C3F47F37-75D8-414A-A8BA-3980EC8A46D7}