From aec0bff757c937489d003ab7b36c52e77e4b096a Mon Sep 17 00:00:00 2001 From: Andrew Murray Date: Tue, 9 Apr 2019 10:52:41 +0100 Subject: arm64: HWCAP: encapsulate elf_hwcap The introduction of AT_HWCAP2 introduced accessors which ensure that hwcap features are set and tested appropriately. Let's now mandate access to elf_hwcap via these accessors by making elf_hwcap static within cpufeature.c. Signed-off-by: Andrew Murray Reviewed-by: Dave Martin Reviewed-by: Suzuki K Poulose Signed-off-by: Will Deacon --- arch/arm64/kernel/cpufeature.c | 33 +++++++++++++++++++++++++++++++-- 1 file changed, 31 insertions(+), 2 deletions(-) (limited to 'arch/arm64/kernel') diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index 986ceeacd19f..a655d1bb1186 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -35,8 +35,8 @@ #include #include -unsigned long elf_hwcap __read_mostly; -EXPORT_SYMBOL_GPL(elf_hwcap); +/* Kernel representation of AT_HWCAP and AT_HWCAP2 */ +static unsigned long elf_hwcap __read_mostly; #ifdef CONFIG_COMPAT #define COMPAT_ELF_HWCAP_DEFAULT \ @@ -1947,6 +1947,35 @@ bool this_cpu_has_cap(unsigned int n) return false; } +void cpu_set_feature(unsigned int num) +{ + WARN_ON(num >= MAX_CPU_FEATURES); + elf_hwcap |= BIT(num); +} +EXPORT_SYMBOL_GPL(cpu_set_feature); + +bool cpu_have_feature(unsigned int num) +{ + WARN_ON(num >= MAX_CPU_FEATURES); + return elf_hwcap & BIT(num); +} +EXPORT_SYMBOL_GPL(cpu_have_feature); + +unsigned long cpu_get_elf_hwcap(void) +{ + /* + * We currently only populate the first 32 bits of AT_HWCAP. Please + * note that for userspace compatibility we guarantee that bits 62 + * and 63 will always be returned as 0. + */ + return lower_32_bits(elf_hwcap); +} + +unsigned long cpu_get_elf_hwcap2(void) +{ + return upper_32_bits(elf_hwcap); +} + static void __init setup_system_capabilities(void) { /* -- cgit v1.2.3