From: Mark Brown <broonie@kernel.org> We have filled all 64 bits of AT_HWCAP2 so in order to support discovery of further features provide the framework to use the already defined AT_HWCAP3 for further CPU features. Signed-off-by: Mark Brown <broonie@kernel.org> Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com> Link: https://lore.kernel.org/r/20241004-arm64-elf-hwcap3-v2-2-799d1daad8b0@kernel... Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> [conflicts with e218c611e32c8d4315a6d64790b9a86f3d4fa4dc] Signed-off-by: Hongye Lin <linhongye@h-partners.com> Signed-off-by: Qi Xi <xiqi2@huawei.com> --- Documentation/arch/arm64/elf_hwcaps.rst | 6 +++--- arch/arm64/include/asm/cpufeature.h | 3 ++- arch/arm64/include/asm/hwcap.h | 5 ++++- arch/arm64/include/uapi/asm/hwcap.h | 4 ++++ arch/arm64/kernel/cpufeature.c | 6 ++++++ 5 files changed, 19 insertions(+), 5 deletions(-) diff --git a/Documentation/arch/arm64/elf_hwcaps.rst b/Documentation/arch/arm64/elf_hwcaps.rst index 76ff9d7398fd..f01ce14bca65 100644 --- a/Documentation/arch/arm64/elf_hwcaps.rst +++ b/Documentation/arch/arm64/elf_hwcaps.rst @@ -16,9 +16,9 @@ architected discovery mechanism available to userspace code at EL0. The kernel exposes the presence of these features to userspace through a set of flags called hwcaps, exposed in the auxiliary vector. -Userspace software can test for features by acquiring the AT_HWCAP or -AT_HWCAP2 entry of the auxiliary vector, and testing whether the relevant -flags are set, e.g.:: +Userspace software can test for features by acquiring the AT_HWCAP, +AT_HWCAP2 or AT_HWCAP3 entry of the auxiliary vector, and testing +whether the relevant flags are set, e.g.:: bool floating_point_is_present(void) { diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h index 5a7f5f3e052d..102bd1194d06 100644 --- a/arch/arm64/include/asm/cpufeature.h +++ b/arch/arm64/include/asm/cpufeature.h @@ -12,7 +12,7 @@ #include <asm/hwcap.h> #include <asm/sysreg.h> -#define MAX_CPU_FEATURES 128 +#define MAX_CPU_FEATURES 192 #define cpu_feature(x) KERNEL_HWCAP_ ## x #define ARM64_SW_FEATURE_OVERRIDE_NOKASLR 0 @@ -434,6 +434,7 @@ void cpu_set_feature(unsigned int num); bool cpu_have_feature(unsigned int num); unsigned long cpu_get_elf_hwcap(void); unsigned long cpu_get_elf_hwcap2(void); +unsigned long cpu_get_elf_hwcap3(void); #define cpu_set_named_feature(name) cpu_set_feature(cpu_feature(name)) #define cpu_have_named_feature(name) cpu_have_feature(cpu_feature(name)) diff --git a/arch/arm64/include/asm/hwcap.h b/arch/arm64/include/asm/hwcap.h index 521267478d18..6f044e5873a9 100644 --- a/arch/arm64/include/asm/hwcap.h +++ b/arch/arm64/include/asm/hwcap.h @@ -140,17 +140,20 @@ #define KERNEL_HWCAP_MOPS __khwcap2_feature(MOPS) #define KERNEL_HWCAP_HBC __khwcap2_feature(HBC) +#define __khwcap3_feature(x) (const_ilog2(HWCAP3_ ## x) + 128) + /* * This yields a mask that user programs can use to figure out what * instruction set this cpu supports. */ #define ELF_HWCAP cpu_get_elf_hwcap() #define ELF_HWCAP2 cpu_get_elf_hwcap2() +#define ELF_HWCAP3 cpu_get_elf_hwcap3() #ifdef CONFIG_COMPAT #define COMPAT_ELF_HWCAP (compat_elf_hwcap) #define COMPAT_ELF_HWCAP2 (compat_elf_hwcap2) -extern unsigned int compat_elf_hwcap, compat_elf_hwcap2; +extern unsigned int compat_elf_hwcap, compat_elf_hwcap2, compat_elf_hwcap3; #endif enum { diff --git a/arch/arm64/include/uapi/asm/hwcap.h b/arch/arm64/include/uapi/asm/hwcap.h index 53026f45a509..a86fca74fdcf 100644 --- a/arch/arm64/include/uapi/asm/hwcap.h +++ b/arch/arm64/include/uapi/asm/hwcap.h @@ -105,4 +105,8 @@ #define HWCAP2_MOPS (1UL << 43) #define HWCAP2_HBC (1UL << 44) +/* + * HWCAP3 flags - for AT_HWCAP3 + */ + #endif /* _UAPI__ASM_HWCAP_H */ diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index 48750a38e455..4cd925bfc513 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -104,6 +104,7 @@ static DECLARE_BITMAP(elf_hwcap, MAX_CPU_FEATURES) __read_mostly; COMPAT_HWCAP_LPAE) unsigned int compat_elf_hwcap __read_mostly = COMPAT_ELF_HWCAP_DEFAULT; unsigned int compat_elf_hwcap2 __read_mostly; +unsigned int compat_elf_hwcap3 __read_mostly; #endif DECLARE_BITMAP(system_cpucaps, ARM64_NCAPS); @@ -3507,6 +3508,11 @@ unsigned long cpu_get_elf_hwcap2(void) return elf_hwcap[1]; } +unsigned long cpu_get_elf_hwcap3(void) +{ + return elf_hwcap[2]; +} + void __init setup_system_features(void) { /* -- 2.33.0