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authorYeoreum Yun <yeoreum.yun@arm.com>2026-03-14 20:51:26 +0300
committerCatalin Marinas <catalin.marinas@arm.com>2026-03-26 21:19:07 +0300
commit7181f718cb0fd47b37d13aad8744cbd6da9f1cbe (patch)
tree399ef77aced5594157f93fd02bceb1fb363e1f5a
parent1f318b96cc84d7c2ab792fcc0bfd42a7ca890681 (diff)
downloadlinux-7181f718cb0fd47b37d13aad8744cbd6da9f1cbe.tar.xz
arm64: cpufeature: Add FEAT_LSUI
Since Armv9.6, FEAT_LSUI introduces atomic instructions that allow privileged code to access user memory without clearing the PSTATE.PAN bit. Add CPU feature detection for FEAT_LSUI. Signed-off-by: Yeoreum Yun <yeoreum.yun@arm.com> [catalin.marinas@arm.com: Remove commit log references to SW_PAN] Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
-rw-r--r--arch/arm64/include/asm/cpucaps.h2
-rw-r--r--arch/arm64/kernel/cpufeature.c10
-rw-r--r--arch/arm64/tools/cpucaps1
3 files changed, 13 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/cpucaps.h b/arch/arm64/include/asm/cpucaps.h
index 177c691914f8..6e3da333442e 100644
--- a/arch/arm64/include/asm/cpucaps.h
+++ b/arch/arm64/include/asm/cpucaps.h
@@ -71,6 +71,8 @@ cpucap_is_possible(const unsigned int cap)
return true;
case ARM64_HAS_PMUV3:
return IS_ENABLED(CONFIG_HW_PERF_EVENTS);
+ case ARM64_HAS_LSUI:
+ return IS_ENABLED(CONFIG_ARM64_LSUI);
}
return true;
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index c31f8e17732a..5074ff32176f 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -281,6 +281,7 @@ static const struct arm64_ftr_bits ftr_id_aa64isar2[] = {
static const struct arm64_ftr_bits ftr_id_aa64isar3[] = {
ARM64_FTR_BITS(FTR_VISIBLE, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64ISAR3_EL1_FPRCVT_SHIFT, 4, 0),
+ ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64ISAR3_EL1_LSUI_SHIFT, 4, ID_AA64ISAR3_EL1_LSUI_NI),
ARM64_FTR_BITS(FTR_VISIBLE, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64ISAR3_EL1_LSFE_SHIFT, 4, 0),
ARM64_FTR_BITS(FTR_VISIBLE, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64ISAR3_EL1_FAMINMAX_SHIFT, 4, 0),
ARM64_FTR_END,
@@ -3169,6 +3170,15 @@ static const struct arm64_cpu_capabilities arm64_features[] = {
.cpu_enable = cpu_enable_ls64_v,
ARM64_CPUID_FIELDS(ID_AA64ISAR1_EL1, LS64, LS64_V)
},
+#ifdef CONFIG_ARM64_LSUI
+ {
+ .desc = "Unprivileged Load Store Instructions (LSUI)",
+ .capability = ARM64_HAS_LSUI,
+ .type = ARM64_CPUCAP_SYSTEM_FEATURE,
+ .matches = has_cpuid_feature,
+ ARM64_CPUID_FIELDS(ID_AA64ISAR3_EL1, LSUI, IMP)
+ },
+#endif
{},
};
diff --git a/arch/arm64/tools/cpucaps b/arch/arm64/tools/cpucaps
index 7261553b644b..b7286d977788 100644
--- a/arch/arm64/tools/cpucaps
+++ b/arch/arm64/tools/cpucaps
@@ -48,6 +48,7 @@ HAS_LPA2
HAS_LSE_ATOMICS
HAS_LS64
HAS_LS64_V
+HAS_LSUI
HAS_MOPS
HAS_NESTED_VIRT
HAS_BBML2_NOABORT