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[PATCH v3 3/7] arm64: HWCAP: encapsulate elf_hwcap
- From: Andrew Murray <andrew dot murray at arm dot com>
- To: Catalin Marinas <catalin dot marinas at arm dot com>, Will Deacon <will dot deacon at arm dot com>
- Cc: Szabolcs Nagy <Szabolcs dot Nagy at arm dot com>, dave dot martin at arm dot com, linux-arm-kernel at lists dot infradead dot org, Mark Rutland <mark dot rutland at arm dot com>, Phil Blundell <pb at pbcl dot net>, libc-alpha at sourceware dot org, linux-api at vger dot kernel dot org
- Date: Mon, 1 Apr 2019 11:45:11 +0100
- Subject: [PATCH v3 3/7] arm64: HWCAP: encapsulate elf_hwcap
- References: <20190401104515.39775-1-andrew.murray@arm.com>
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 <andrew.murray@arm.com>
---
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 <uapi/asm/hwcap.h>
+#include <asm/cpufeature.h>
#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 <linux/kernel.h>
/*
* 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 <asm/traps.h>
#include <asm/virt.h>
-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)
{
/*
--
2.21.0