summaryrefslogtreecommitdiff
path: root/arch/x86/include/asm/string_64.h
diff options
context:
space:
mode:
authorTony Luck <tony.luck@intel.com>2016-02-18 22:47:26 +0300
committerIngo Molnar <mingo@kernel.org>2016-03-08 19:54:38 +0300
commit92b0729c34cab1f46d89aace3e66015f0bb4a682 (patch)
treec1509bb8d1dc7044bb2d68a280799e4ccdca2da9 /arch/x86/include/asm/string_64.h
parentea2ca36b658cfc6081ee454e97593c81f646806e (diff)
downloadlinux-92b0729c34cab1f46d89aace3e66015f0bb4a682.tar.xz
x86/mm, x86/mce: Add memcpy_mcsafe()
Make use of the EXTABLE_FAULT exception table entries to write a kernel copy routine that doesn't crash the system if it encounters a machine check. Prime use case for this is to copy from large arrays of non-volatile memory used as storage. We have to use an unrolled copy loop for now because current hardware implementations treat a machine check in "rep mov" as fatal. When that is fixed we can simplify. Return type is a "bool". True means that we copied OK, false means that it didn't. Signed-off-by: Tony Luck <tony.luck@intel.com> 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 <a.p.zijlstra@chello.nl> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@gmail.com> Link: http://lkml.kernel.org/r/a44e1055efc2d2a9473307b22c91caa437aa3f8b.1456439214.git.tony.luck@intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/include/asm/string_64.h')
-rw-r--r--arch/x86/include/asm/string_64.h13
1 files changed, 13 insertions, 0 deletions
diff --git a/arch/x86/include/asm/string_64.h b/arch/x86/include/asm/string_64.h
index ff8b9a17dc4b..ca6ba3607705 100644
--- a/arch/x86/include/asm/string_64.h
+++ b/arch/x86/include/asm/string_64.h
@@ -78,6 +78,19 @@ int strcmp(const char *cs, const char *ct);
#define memset(s, c, n) __memset(s, c, n)
#endif
+/**
+ * memcpy_mcsafe - copy memory with indication if a machine check happened
+ *
+ * @dst: destination address
+ * @src: source address
+ * @cnt: number of bytes to copy
+ *
+ * Low level memory copy function that catches machine checks
+ *
+ * Return true for success, false for fail
+ */
+bool memcpy_mcsafe(void *dst, const void *src, size_t cnt);
+
#endif /* __KERNEL__ */
#endif /* _ASM_X86_STRING_64_H */