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Diffstat (limited to 'arch/x86/lib/usercopy_64.c')
-rw-r--r--arch/x86/lib/usercopy_64.c30
1 files changed, 25 insertions, 5 deletions
diff --git a/arch/x86/lib/usercopy_64.c b/arch/x86/lib/usercopy_64.c
index 75d3776123cc..9c5606d88f61 100644
--- a/arch/x86/lib/usercopy_64.c
+++ b/arch/x86/lib/usercopy_64.c
@@ -23,13 +23,13 @@ unsigned long __clear_user(void __user *addr, unsigned long size)
asm volatile(
" testq %[size8],%[size8]\n"
" jz 4f\n"
- "0: movq %[zero],(%[dst])\n"
- " addq %[eight],%[dst]\n"
+ "0: movq $0,(%[dst])\n"
+ " addq $8,%[dst]\n"
" decl %%ecx ; jnz 0b\n"
"4: movq %[size1],%%rcx\n"
" testl %%ecx,%%ecx\n"
" jz 2f\n"
- "1: movb %b[zero],(%[dst])\n"
+ "1: movb $0,(%[dst])\n"
" incq %[dst]\n"
" decl %%ecx ; jnz 1b\n"
"2:\n"
@@ -40,8 +40,7 @@ unsigned long __clear_user(void __user *addr, unsigned long size)
_ASM_EXTABLE(0b,3b)
_ASM_EXTABLE(1b,2b)
: [size8] "=&c"(size), [dst] "=&D" (__d0)
- : [size1] "r"(size & 7), "[size8]" (size / 8), "[dst]"(addr),
- [zero] "r" (0UL), [eight] "r" (8UL));
+ : [size1] "r"(size & 7), "[size8]" (size / 8), "[dst]"(addr));
clac();
return size;
}
@@ -75,6 +74,27 @@ copy_user_handle_tail(char *to, char *from, unsigned len)
return len;
}
+/*
+ * Similar to copy_user_handle_tail, probe for the write fault point,
+ * but reuse __memcpy_mcsafe in case a new read error is encountered.
+ * clac() is handled in _copy_to_iter_mcsafe().
+ */
+__visible unsigned long
+mcsafe_handle_tail(char *to, char *from, unsigned len)
+{
+ for (; len; --len, to++, from++) {
+ /*
+ * Call the assembly routine back directly since
+ * memcpy_mcsafe() may silently fallback to memcpy.
+ */
+ unsigned long rem = __memcpy_mcsafe(to, from, 1);
+
+ if (rem)
+ break;
+ }
+ return len;
+}
+
#ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE
/**
* clean_cache_range - write back a cache range with CLWB