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Diffstat (limited to 'arch/x86/include/asm/smap.h')
-rw-r--r--arch/x86/include/asm/smap.h37
1 files changed, 28 insertions, 9 deletions
diff --git a/arch/x86/include/asm/smap.h b/arch/x86/include/asm/smap.h
index db333300bd4b..f94a7d0ddd49 100644
--- a/arch/x86/include/asm/smap.h
+++ b/arch/x86/include/asm/smap.h
@@ -13,13 +13,12 @@
#ifndef _ASM_X86_SMAP_H
#define _ASM_X86_SMAP_H
-#include <linux/stringify.h>
#include <asm/nops.h>
#include <asm/cpufeatures.h>
/* "Raw" instruction opcodes */
-#define __ASM_CLAC .byte 0x0f,0x01,0xca
-#define __ASM_STAC .byte 0x0f,0x01,0xcb
+#define __ASM_CLAC ".byte 0x0f,0x01,0xca"
+#define __ASM_STAC ".byte 0x0f,0x01,0xcb"
#ifdef __ASSEMBLY__
@@ -28,10 +27,10 @@
#ifdef CONFIG_X86_SMAP
#define ASM_CLAC \
- ALTERNATIVE "", __stringify(__ASM_CLAC), X86_FEATURE_SMAP
+ ALTERNATIVE "", __ASM_CLAC, X86_FEATURE_SMAP
#define ASM_STAC \
- ALTERNATIVE "", __stringify(__ASM_STAC), X86_FEATURE_SMAP
+ ALTERNATIVE "", __ASM_STAC, X86_FEATURE_SMAP
#else /* CONFIG_X86_SMAP */
@@ -49,26 +48,46 @@
static __always_inline void clac(void)
{
/* Note: a barrier is implicit in alternative() */
- alternative("", __stringify(__ASM_CLAC), X86_FEATURE_SMAP);
+ alternative("", __ASM_CLAC, X86_FEATURE_SMAP);
}
static __always_inline void stac(void)
{
/* Note: a barrier is implicit in alternative() */
- alternative("", __stringify(__ASM_STAC), X86_FEATURE_SMAP);
+ alternative("", __ASM_STAC, X86_FEATURE_SMAP);
+}
+
+static __always_inline unsigned long smap_save(void)
+{
+ unsigned long flags;
+
+ asm volatile (ALTERNATIVE("", "pushf; pop %0; " __ASM_CLAC,
+ X86_FEATURE_SMAP)
+ : "=rm" (flags) : : "memory", "cc");
+
+ return flags;
+}
+
+static __always_inline void smap_restore(unsigned long flags)
+{
+ asm volatile (ALTERNATIVE("", "push %0; popf", X86_FEATURE_SMAP)
+ : : "g" (flags) : "memory", "cc");
}
/* These macros can be used in asm() statements */
#define ASM_CLAC \
- ALTERNATIVE("", __stringify(__ASM_CLAC), X86_FEATURE_SMAP)
+ ALTERNATIVE("", __ASM_CLAC, X86_FEATURE_SMAP)
#define ASM_STAC \
- ALTERNATIVE("", __stringify(__ASM_STAC), X86_FEATURE_SMAP)
+ ALTERNATIVE("", __ASM_STAC, X86_FEATURE_SMAP)
#else /* CONFIG_X86_SMAP */
static inline void clac(void) { }
static inline void stac(void) { }
+static inline unsigned long smap_save(void) { return 0; }
+static inline void smap_restore(unsigned long flags) { }
+
#define ASM_CLAC
#define ASM_STAC