From: Joey Gouly <joey.gouly@arm.com>
Date: Fri, 4 Aug 2023 15:37:45 +0100
Subject: arm64: add HWCAP for FEAT_HBC (hinted conditional branches)
Git-commit: 7f86d128e437990fd08d9e66ae7c1571666cff8a
Patch-mainline: v6.6-rc1
References: git-fixes
Add a HWCAP for FEAT_HBC, so that userspace can make a decision on using
this feature.
Signed-off-by: Joey Gouly <joey.gouly@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20230804143746.3900803-2-joey.gouly@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
Acked-by: Ivan T. Ivanov <iivanov@suse.de>
---
arch/arm64/include/asm/hwcap.h | 1 +
arch/arm64/include/uapi/asm/hwcap.h | 1 +
arch/arm64/kernel/cpufeature.c | 3 ++-
arch/arm64/kernel/cpuinfo.c | 1 +
4 files changed, 5 insertions(+), 1 deletion(-)
--- a/arch/arm64/include/asm/hwcap.h
+++ b/arch/arm64/include/asm/hwcap.h
@@ -137,6 +137,7 @@
#define KERNEL_HWCAP_SME_BI32I32 __khwcap2_feature(SME_BI32I32)
#define KERNEL_HWCAP_SME_B16B16 __khwcap2_feature(SME_B16B16)
#define KERNEL_HWCAP_SME_F16F16 __khwcap2_feature(SME_F16F16)
+#define KERNEL_HWCAP_HBC __khwcap2_feature(HBC)
/*
* This yields a mask that user programs can use to figure out what
--- a/arch/arm64/include/uapi/asm/hwcap.h
+++ b/arch/arm64/include/uapi/asm/hwcap.h
@@ -102,5 +102,6 @@
#define HWCAP2_SME_BI32I32 (1UL << 40)
#define HWCAP2_SME_B16B16 (1UL << 41)
#define HWCAP2_SME_F16F16 (1UL << 42)
+#define HWCAP2_HBC (1UL << 44)
#endif /* _UAPI__ASM_HWCAP_H */
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -222,7 +222,7 @@ static const struct arm64_ftr_bits ftr_i
static const struct arm64_ftr_bits ftr_id_aa64isar2[] = {
ARM64_FTR_BITS(FTR_VISIBLE, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64ISAR2_EL1_CSSC_SHIFT, 4, 0),
ARM64_FTR_BITS(FTR_VISIBLE, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64ISAR2_EL1_RPRFM_SHIFT, 4, 0),
- ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_HIGHER_SAFE, ID_AA64ISAR2_EL1_BC_SHIFT, 4, 0),
+ ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_HIGHER_SAFE, ID_AA64ISAR2_EL1_BC_SHIFT, 4, 0),
ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_PTR_AUTH),
FTR_STRICT, FTR_EXACT, ID_AA64ISAR2_EL1_APA3_SHIFT, 4, 0),
ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_PTR_AUTH),
@@ -2736,6 +2736,7 @@ static const struct arm64_cpu_capabiliti
HWCAP_CAP(ID_AA64ISAR1_EL1, DGH, IMP, CAP_HWCAP, KERNEL_HWCAP_DGH),
HWCAP_CAP(ID_AA64ISAR1_EL1, I8MM, IMP, CAP_HWCAP, KERNEL_HWCAP_I8MM),
HWCAP_CAP(ID_AA64MMFR2_EL1, AT, IMP, CAP_HWCAP, KERNEL_HWCAP_USCAT),
+ HWCAP_CAP(ID_AA64ISAR2_EL1, BC, IMP, CAP_HWCAP, KERNEL_HWCAP_HBC),
#ifdef CONFIG_ARM64_SVE
HWCAP_CAP(ID_AA64PFR0_EL1, SVE, IMP, CAP_HWCAP, KERNEL_HWCAP_SVE),
HWCAP_CAP(ID_AA64ZFR0_EL1, SVEver, SVE2p1, CAP_HWCAP, KERNEL_HWCAP_SVE2P1),
--- a/arch/arm64/kernel/cpuinfo.c
+++ b/arch/arm64/kernel/cpuinfo.c
@@ -125,6 +125,7 @@ static const char *const hwcap_str[] = {
[KERNEL_HWCAP_SME_BI32I32] = "smebi32i32",
[KERNEL_HWCAP_SME_B16B16] = "smeb16b16",
[KERNEL_HWCAP_SME_F16F16] = "smef16f16",
+ [KERNEL_HWCAP_HBC] = "hbc",
};
#ifdef CONFIG_COMPAT