From patchwork Mon Apr 1 10:45:11 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Murray X-Patchwork-Id: 32116 Received: (qmail 89865 invoked by alias); 1 Apr 2019 10:45:41 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Delivered-To: mailing list libc-alpha@sourceware.org Received: (qmail 89744 invoked by uid 89); 1 Apr 2019 10:45:36 -0000 Authentication-Results: sourceware.org; auth=none X-Spam-SWARE-Status: No, score=-21.2 required=5.0 tests=AWL, BAYES_00, GIT_PATCH_0, GIT_PATCH_1, GIT_PATCH_2, GIT_PATCH_3 autolearn=ham version=3.3.1 spammy=cap X-HELO: foss.arm.com From: Andrew Murray To: Catalin Marinas , Will Deacon Cc: Szabolcs Nagy , dave.martin@arm.com, linux-arm-kernel@lists.infradead.org, Mark Rutland , Phil Blundell , libc-alpha@sourceware.org, linux-api@vger.kernel.org Subject: [PATCH v3 3/7] arm64: HWCAP: encapsulate elf_hwcap Date: Mon, 1 Apr 2019 11:45:11 +0100 Message-Id: <20190401104515.39775-4-andrew.murray@arm.com> In-Reply-To: <20190401104515.39775-1-andrew.murray@arm.com> References: <20190401104515.39775-1-andrew.murray@arm.com> MIME-Version: 1.0 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 --- arch/arm64/include/asm/cpufeature.h | 15 ++++---------- arch/arm64/include/asm/hwcap.h | 7 +++---- arch/arm64/kernel/cpufeature.c | 32 +++++++++++++++++++++++++++-- 3 files changed, 37 insertions(+), 17 deletions(-) diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h index f06e1da1d678..4c766f831de6 100644 --- a/arch/arm64/include/asm/cpufeature.h +++ b/arch/arm64/include/asm/cpufeature.h @@ -392,19 +392,12 @@ extern DECLARE_BITMAP(boot_capabilities, ARM64_NPATCHABLE); for_each_set_bit(cap, cpu_hwcaps, ARM64_NCAPS) bool this_cpu_has_cap(unsigned int cap); +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); -static inline void cpu_set_feature(unsigned int num) -{ - WARN_ON(num >= MAX_CPU_FEATURES); - elf_hwcap |= BIT(num); -} #define cpu_set_named_feature(name) cpu_set_feature(cpu_feature(name)) - -static inline bool cpu_have_feature(unsigned int num) -{ - WARN_ON(num >= MAX_CPU_FEATURES); - return elf_hwcap & BIT(num); -} #define cpu_have_named_feature(name) cpu_have_feature(cpu_feature(name)) /* System capability check for constant caps */ diff --git a/arch/arm64/include/asm/hwcap.h b/arch/arm64/include/asm/hwcap.h index d21fe3314d90..de9a66672ba7 100644 --- a/arch/arm64/include/asm/hwcap.h +++ b/arch/arm64/include/asm/hwcap.h @@ -17,6 +17,7 @@ #define __ASM_HWCAP_H #include +#include #define COMPAT_HWCAP_HALF (1 << 1) #define COMPAT_HWCAP_THUMB (1 << 2) @@ -84,14 +85,13 @@ #define KERNEL_HWCAP_DCPODP (ilog2(HWCAP2_DCPODP) + 32) #ifndef __ASSEMBLY__ -#include /* * This yields a mask that user programs can use to figure out what * instruction set this cpu supports. */ -#define ELF_HWCAP lower_32_bits(elf_hwcap) -#define ELF_HWCAP2 upper_32_bits(elf_hwcap) +#define ELF_HWCAP cpu_get_elf_hwcap() +#define ELF_HWCAP2 cpu_get_elf_hwcap2() #ifdef CONFIG_COMPAT #define COMPAT_ELF_HWCAP (compat_elf_hwcap) @@ -107,6 +107,5 @@ enum { #endif }; -extern unsigned long elf_hwcap; #endif #endif diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index 986ceeacd19f..84ca52fa75e5 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -35,8 +35,7 @@ #include #include -unsigned long elf_hwcap __read_mostly; -EXPORT_SYMBOL_GPL(elf_hwcap); +static unsigned long elf_hwcap __read_mostly; #ifdef CONFIG_COMPAT #define COMPAT_ELF_HWCAP_DEFAULT \ @@ -1947,6 +1946,35 @@ 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 bit 62 + * 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) { /*