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9a6fb28a35
Use the mcsafe_key defined in the previous patch to make decisions on which copy function to use. We can't use the FEATURE bit any more because PCI quirks run too late to affect the patching of code. So we use a static key. Turn memcpy_mcsafe() into an inline function to make life easier for callers. The assembly code that actually does the copy is now named memcpy_mcsafe_unrolled() Signed-off-by: Tony Luck <tony.luck@intel.com> Acked-by: Borislav Petkov <bp@suse.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Boris Petkov <bp@suse.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/bfde2fc774e94f53d91b70a4321c85a0d33e7118.1472754712.git.tony.luck@intel.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
114 lines
3.1 KiB
C
114 lines
3.1 KiB
C
#ifndef _ASM_X86_STRING_64_H
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#define _ASM_X86_STRING_64_H
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#ifdef __KERNEL__
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#include <linux/jump_label.h>
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/* Written 2002 by Andi Kleen */
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/* Only used for special circumstances. Stolen from i386/string.h */
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static __always_inline void *__inline_memcpy(void *to, const void *from, size_t n)
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{
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unsigned long d0, d1, d2;
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asm volatile("rep ; movsl\n\t"
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"testb $2,%b4\n\t"
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"je 1f\n\t"
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"movsw\n"
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"1:\ttestb $1,%b4\n\t"
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"je 2f\n\t"
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"movsb\n"
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"2:"
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: "=&c" (d0), "=&D" (d1), "=&S" (d2)
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: "0" (n / 4), "q" (n), "1" ((long)to), "2" ((long)from)
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: "memory");
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return to;
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}
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/* Even with __builtin_ the compiler may decide to use the out of line
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function. */
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#define __HAVE_ARCH_MEMCPY 1
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extern void *memcpy(void *to, const void *from, size_t len);
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extern void *__memcpy(void *to, const void *from, size_t len);
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#ifndef CONFIG_KMEMCHECK
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#if (__GNUC__ == 4 && __GNUC_MINOR__ < 3) || __GNUC__ < 4
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#define memcpy(dst, src, len) \
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({ \
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size_t __len = (len); \
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void *__ret; \
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if (__builtin_constant_p(len) && __len >= 64) \
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__ret = __memcpy((dst), (src), __len); \
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else \
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__ret = __builtin_memcpy((dst), (src), __len); \
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__ret; \
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})
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#endif
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#else
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/*
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* kmemcheck becomes very happy if we use the REP instructions unconditionally,
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* because it means that we know both memory operands in advance.
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*/
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#define memcpy(dst, src, len) __inline_memcpy((dst), (src), (len))
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#endif
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#define __HAVE_ARCH_MEMSET
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void *memset(void *s, int c, size_t n);
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void *__memset(void *s, int c, size_t n);
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#define __HAVE_ARCH_MEMMOVE
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void *memmove(void *dest, const void *src, size_t count);
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void *__memmove(void *dest, const void *src, size_t count);
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int memcmp(const void *cs, const void *ct, size_t count);
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size_t strlen(const char *s);
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char *strcpy(char *dest, const char *src);
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char *strcat(char *dest, const char *src);
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int strcmp(const char *cs, const char *ct);
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#if defined(CONFIG_KASAN) && !defined(__SANITIZE_ADDRESS__)
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/*
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* For files that not instrumented (e.g. mm/slub.c) we
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* should use not instrumented version of mem* functions.
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*/
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#undef memcpy
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#define memcpy(dst, src, len) __memcpy(dst, src, len)
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#define memmove(dst, src, len) __memmove(dst, src, len)
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#define memset(s, c, n) __memset(s, c, n)
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#endif
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__must_check int memcpy_mcsafe_unrolled(void *dst, const void *src, size_t cnt);
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DECLARE_STATIC_KEY_FALSE(mcsafe_key);
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/**
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* memcpy_mcsafe - copy memory with indication if a machine check happened
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*
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* @dst: destination address
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* @src: source address
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* @cnt: number of bytes to copy
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*
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* Low level memory copy function that catches machine checks
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* We only call into the "safe" function on systems that can
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* actually do machine check recovery. Everyone else can just
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* use memcpy().
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*
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* Return 0 for success, -EFAULT for fail
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*/
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static __always_inline __must_check int
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memcpy_mcsafe(void *dst, const void *src, size_t cnt)
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{
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#ifdef CONFIG_X86_MCE
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if (static_branch_unlikely(&mcsafe_key))
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return memcpy_mcsafe_unrolled(dst, src, cnt);
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else
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#endif
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memcpy(dst, src, cnt);
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return 0;
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}
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#endif /* __KERNEL__ */
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#endif /* _ASM_X86_STRING_64_H */
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