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authorLinus Torvalds <torvalds@linux-foundation.org>2014-01-21 02:46:32 +0400
committerLinus Torvalds <torvalds@linux-foundation.org>2014-01-21 02:46:32 +0400
commitc9cdd9a6ae49704f12a289706551536ec842693f (patch)
tree21a79d8731065352e924f2bcecf257a4247c2f64 /arch/x86/include/asm/uaccess.h
parentf4bcd8ccddb02833340652e9f46f5127828eb79d (diff)
parent741e3902cd89a7fbc04ae53f29a7ca0da452aa8e (diff)
downloadlinux-c9cdd9a6ae49704f12a289706551536ec842693f.tar.xz
Merge branch 'x86/mpx' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 cpufeature and mpx updates from Peter Anvin: "This includes the basic infrastructure for MPX (Memory Protection Extensions) support, but does not include MPX support itself. It is, however, a prerequisite for KVM support for MPX, which I believe will be pushed later this merge window by the KVM team. This includes moving the functionality in futex_atomic_cmpxchg_inatomic() into a new function in uaccess.h so it can be reused - this will be used by the final MPX patches. The actual MPX functionality (map management and so on) will be pushed in a future merge window, when ready" * 'x86/mpx' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/intel/mpx: Remove unused LWP structure x86, mpx: Add MPX related opcodes to the x86 opcode map x86: replace futex_atomic_cmpxchg_inatomic() with user_atomic_cmpxchg_inatomic x86: add user_atomic_cmpxchg_inatomic at uaccess.h x86, xsave: Support eager-only xsave features, add MPX support x86, cpufeature: Define the Intel MPX feature flag
Diffstat (limited to 'arch/x86/include/asm/uaccess.h')
-rw-r--r--arch/x86/include/asm/uaccess.h92
1 files changed, 92 insertions, 0 deletions
diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h
index 6f1bb74d547b..0d592e0a5b84 100644
--- a/arch/x86/include/asm/uaccess.h
+++ b/arch/x86/include/asm/uaccess.h
@@ -533,6 +533,98 @@ extern __must_check long strnlen_user(const char __user *str, long n);
unsigned long __must_check clear_user(void __user *mem, unsigned long len);
unsigned long __must_check __clear_user(void __user *mem, unsigned long len);
+extern void __cmpxchg_wrong_size(void)
+ __compiletime_error("Bad argument size for cmpxchg");
+
+#define __user_atomic_cmpxchg_inatomic(uval, ptr, old, new, size) \
+({ \
+ int __ret = 0; \
+ __typeof__(ptr) __uval = (uval); \
+ __typeof__(*(ptr)) __old = (old); \
+ __typeof__(*(ptr)) __new = (new); \
+ switch (size) { \
+ case 1: \
+ { \
+ asm volatile("\t" ASM_STAC "\n" \
+ "1:\t" LOCK_PREFIX "cmpxchgb %4, %2\n" \
+ "2:\t" ASM_CLAC "\n" \
+ "\t.section .fixup, \"ax\"\n" \
+ "3:\tmov %3, %0\n" \
+ "\tjmp 2b\n" \
+ "\t.previous\n" \
+ _ASM_EXTABLE(1b, 3b) \
+ : "+r" (__ret), "=a" (__old), "+m" (*(ptr)) \
+ : "i" (-EFAULT), "q" (__new), "1" (__old) \
+ : "memory" \
+ ); \
+ break; \
+ } \
+ case 2: \
+ { \
+ asm volatile("\t" ASM_STAC "\n" \
+ "1:\t" LOCK_PREFIX "cmpxchgw %4, %2\n" \
+ "2:\t" ASM_CLAC "\n" \
+ "\t.section .fixup, \"ax\"\n" \
+ "3:\tmov %3, %0\n" \
+ "\tjmp 2b\n" \
+ "\t.previous\n" \
+ _ASM_EXTABLE(1b, 3b) \
+ : "+r" (__ret), "=a" (__old), "+m" (*(ptr)) \
+ : "i" (-EFAULT), "r" (__new), "1" (__old) \
+ : "memory" \
+ ); \
+ break; \
+ } \
+ case 4: \
+ { \
+ asm volatile("\t" ASM_STAC "\n" \
+ "1:\t" LOCK_PREFIX "cmpxchgl %4, %2\n" \
+ "2:\t" ASM_CLAC "\n" \
+ "\t.section .fixup, \"ax\"\n" \
+ "3:\tmov %3, %0\n" \
+ "\tjmp 2b\n" \
+ "\t.previous\n" \
+ _ASM_EXTABLE(1b, 3b) \
+ : "+r" (__ret), "=a" (__old), "+m" (*(ptr)) \
+ : "i" (-EFAULT), "r" (__new), "1" (__old) \
+ : "memory" \
+ ); \
+ break; \
+ } \
+ case 8: \
+ { \
+ if (!IS_ENABLED(CONFIG_X86_64)) \
+ __cmpxchg_wrong_size(); \
+ \
+ asm volatile("\t" ASM_STAC "\n" \
+ "1:\t" LOCK_PREFIX "cmpxchgq %4, %2\n" \
+ "2:\t" ASM_CLAC "\n" \
+ "\t.section .fixup, \"ax\"\n" \
+ "3:\tmov %3, %0\n" \
+ "\tjmp 2b\n" \
+ "\t.previous\n" \
+ _ASM_EXTABLE(1b, 3b) \
+ : "+r" (__ret), "=a" (__old), "+m" (*(ptr)) \
+ : "i" (-EFAULT), "r" (__new), "1" (__old) \
+ : "memory" \
+ ); \
+ break; \
+ } \
+ default: \
+ __cmpxchg_wrong_size(); \
+ } \
+ *__uval = __old; \
+ __ret; \
+})
+
+#define user_atomic_cmpxchg_inatomic(uval, ptr, old, new) \
+({ \
+ access_ok(VERIFY_WRITE, (ptr), sizeof(*(ptr))) ? \
+ __user_atomic_cmpxchg_inatomic((uval), (ptr), \
+ (old), (new), sizeof(*(ptr))) : \
+ -EFAULT; \
+})
+
/*
* movsl can be slow when source and dest are not both 8-byte aligned
*/