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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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60622d6822
Machine check safe memory copies are currently deployed in the pmem driver whenever reading from persistent memory media, so that -EIO is returned rather than triggering a kernel panic. While this protects most pmem accesses, it is not complete in the filesystem-dax case. When filesystem-dax is enabled reads may bypass the block layer and the driver via dax_iomap_actor() and its usage of copy_to_iter(). In preparation for creating a copy_to_iter() variant that can handle machine checks, teach memcpy_mcsafe() to return the number of bytes remaining rather than -EFAULT when an exception occurs. Co-developed-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: hch@lst.de Cc: linux-fsdevel@vger.kernel.org Cc: linux-nvdimm@lists.01.org Link: http://lkml.kernel.org/r/152539238119.31796.14318473522414462886.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
158 lines
4.0 KiB
C
158 lines
4.0 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#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_FORTIFY_SOURCE
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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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#endif /* !CONFIG_FORTIFY_SOURCE */
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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_MEMSET16
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static inline void *memset16(uint16_t *s, uint16_t v, size_t n)
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{
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long d0, d1;
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asm volatile("rep\n\t"
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"stosw"
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: "=&c" (d0), "=&D" (d1)
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: "a" (v), "1" (s), "0" (n)
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: "memory");
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return s;
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}
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#define __HAVE_ARCH_MEMSET32
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static inline void *memset32(uint32_t *s, uint32_t v, size_t n)
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{
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long d0, d1;
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asm volatile("rep\n\t"
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"stosl"
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: "=&c" (d0), "=&D" (d1)
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: "a" (v), "1" (s), "0" (n)
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: "memory");
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return s;
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}
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#define __HAVE_ARCH_MEMSET64
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static inline void *memset64(uint64_t *s, uint64_t v, size_t n)
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{
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long d0, d1;
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asm volatile("rep\n\t"
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"stosq"
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: "=&c" (d0), "=&D" (d1)
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: "a" (v), "1" (s), "0" (n)
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: "memory");
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return s;
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}
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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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#ifndef __NO_FORTIFY
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#define __NO_FORTIFY /* FORTIFY_SOURCE uses __builtin_memcpy, etc. */
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#endif
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#endif
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#define __HAVE_ARCH_MEMCPY_MCSAFE 1
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__must_check unsigned long __memcpy_mcsafe(void *dst, const void *src,
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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, or number of bytes not copied if there was an
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* exception.
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*/
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static __always_inline __must_check unsigned long
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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(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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#ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE
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#define __HAVE_ARCH_MEMCPY_FLUSHCACHE 1
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void memcpy_flushcache(void *dst, const void *src, size_t cnt);
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#endif
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#endif /* __KERNEL__ */
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#endif /* _ASM_X86_STRING_64_H */
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