From: Vladimir Murzin <vladimir.murzin@arm.com>
To: linux-arm-kernel@lists.infradead.org
Cc: keescook@chromium.org, dave.martin@arm.com,
catalin.marinas@arm.com, will@kernel.org
Subject: [PATCH v4 2/2] arm64: Introduce HWCAPS2_EXECONLY
Date: Fri, 12 Mar 2021 17:38:11 +0000 [thread overview]
Message-ID: <20210312173811.58284-3-vladimir.murzin@arm.com> (raw)
In-Reply-To: <20210312173811.58284-1-vladimir.murzin@arm.com>
With EPAN supported it might be handy to user know that PROT_EXEC
gives execute-only permission, so advertise it via HWCAPS2_EXECONLY
Cc: Kees Cook <keescook@chromium.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
---
arch/arm64/include/asm/hwcap.h | 1 +
arch/arm64/include/asm/sysreg.h | 1 +
arch/arm64/include/uapi/asm/hwcap.h | 1 +
arch/arm64/kernel/cpufeature.c | 3 +++
arch/arm64/kernel/cpuinfo.c | 1 +
5 files changed, 7 insertions(+)
diff --git a/arch/arm64/include/asm/hwcap.h b/arch/arm64/include/asm/hwcap.h
index 9a5498c2c8ee..5ee5bce79233 100644
--- a/arch/arm64/include/asm/hwcap.h
+++ b/arch/arm64/include/asm/hwcap.h
@@ -105,6 +105,7 @@
#define KERNEL_HWCAP_RNG __khwcap2_feature(RNG)
#define KERNEL_HWCAP_BTI __khwcap2_feature(BTI)
#define KERNEL_HWCAP_MTE __khwcap2_feature(MTE)
+#define KERNEL_HWCAP_EXECONLY __khwcap2_feature(EXECONLY)
/*
* This yields a mask that user programs can use to figure out what
diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h
index 817cb3dbcb79..7421139dc44f 100644
--- a/arch/arm64/include/asm/sysreg.h
+++ b/arch/arm64/include/asm/sysreg.h
@@ -817,6 +817,7 @@
#define ID_AA64MMFR1_VMIDBITS_8 0
#define ID_AA64MMFR1_VMIDBITS_16 2
+#define ID_AA64MMFR1_EPAN 3
/* id_aa64mmfr2 */
#define ID_AA64MMFR2_E0PD_SHIFT 60
diff --git a/arch/arm64/include/uapi/asm/hwcap.h b/arch/arm64/include/uapi/asm/hwcap.h
index b8f41aa234ee..61471f47db32 100644
--- a/arch/arm64/include/uapi/asm/hwcap.h
+++ b/arch/arm64/include/uapi/asm/hwcap.h
@@ -75,5 +75,6 @@
#define HWCAP2_RNG (1 << 16)
#define HWCAP2_BTI (1 << 17)
#define HWCAP2_MTE (1 << 18)
+#define HWCAP2_EXECONLY (1 << 19)
#endif /* _UAPI__ASM_HWCAP_H */
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 2ab04967dca7..a49bccb80873 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -2332,6 +2332,9 @@ static const struct arm64_cpu_capabilities arm64_elf_hwcaps[] = {
#ifdef CONFIG_ARM64_MTE
HWCAP_CAP(SYS_ID_AA64PFR1_EL1, ID_AA64PFR1_MTE_SHIFT, FTR_UNSIGNED, ID_AA64PFR1_MTE, CAP_HWCAP, KERNEL_HWCAP_MTE),
#endif /* CONFIG_ARM64_MTE */
+#ifdef CONFIG_ARM64_EPAN
+ HWCAP_CAP(SYS_ID_AA64MMFR1_EL1, ID_AA64MMFR1_PAN_SHIFT, FTR_UNSIGNED, ID_AA64MMFR1_EPAN, CAP_HWCAP, KERNEL_HWCAP_EXECONLY),
+#endif
{},
};
diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c
index 77605aec25fe..34c98d984fe3 100644
--- a/arch/arm64/kernel/cpuinfo.c
+++ b/arch/arm64/kernel/cpuinfo.c
@@ -94,6 +94,7 @@ static const char *const hwcap_str[] = {
[KERNEL_HWCAP_RNG] = "rng",
[KERNEL_HWCAP_BTI] = "bti",
[KERNEL_HWCAP_MTE] = "mte",
+ [KERNEL_HWCAP_EXECONLY] = "xo",
};
#ifdef CONFIG_COMPAT
--
2.24.0
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next prev parent reply other threads:[~2021-03-12 17:40 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-12 17:38 [PATCH v4 0/2] arm64: Support Enhanced PAN Vladimir Murzin
2021-03-12 17:38 ` [PATCH v4 1/2] arm64: Support execute-only permissions with " Vladimir Murzin
2021-03-25 19:06 ` Will Deacon
2021-03-26 11:04 ` Catalin Marinas
2021-03-30 8:47 ` Geert Uytterhoeven
2021-03-30 9:30 ` Catalin Marinas
2021-03-30 9:34 ` Geert Uytterhoeven
2021-03-12 17:38 ` Vladimir Murzin [this message]
2021-03-25 19:00 ` [PATCH v4 2/2] arm64: Introduce HWCAPS2_EXECONLY Will Deacon
2021-03-26 9:35 ` Catalin Marinas
2021-03-29 8:53 ` Will Deacon
2021-03-26 11:05 ` (subset) [PATCH v4 0/2] arm64: Support Enhanced PAN Catalin Marinas
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