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-rw-r--r--lib/strncpy_from_user.c47
1 files changed, 7 insertions, 40 deletions
diff --git a/lib/strncpy_from_user.c b/lib/strncpy_from_user.c
index c4c09b0e96b..bb2b201d6ad 100644
--- a/lib/strncpy_from_user.c
+++ b/lib/strncpy_from_user.c
@@ -4,37 +4,7 @@
#include <linux/errno.h>
#include <asm/byteorder.h>
-
-static inline long find_zero(unsigned long mask)
-{
- long byte = 0;
-
-#ifdef __BIG_ENDIAN
-#ifdef CONFIG_64BIT
- if (mask >> 32)
- mask >>= 32;
- else
- byte = 4;
-#endif
- if (mask >> 16)
- mask >>= 16;
- else
- byte += 2;
- return (mask >> 8) ? byte : byte + 1;
-#else
-#ifdef CONFIG_64BIT
- if (!((unsigned int) mask)) {
- mask >>= 32;
- byte = 4;
- }
-#endif
- if (!(mask & 0xffff)) {
- mask >>= 16;
- byte += 2;
- }
- return (mask & 0xff) ? byte : byte + 1;
-#endif
-}
+#include <asm/word-at-a-time.h>
#ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
#define IS_UNALIGNED(src, dst) 0
@@ -51,8 +21,7 @@ static inline long find_zero(unsigned long mask)
*/
static inline long do_strncpy_from_user(char *dst, const char __user *src, long count, unsigned long max)
{
- const unsigned long high_bits = REPEAT_BYTE(0xfe) + 1;
- const unsigned long low_bits = REPEAT_BYTE(0x7f);
+ const struct word_at_a_time constants = WORD_AT_A_TIME_CONSTANTS;
long res = 0;
/*
@@ -66,18 +35,16 @@ static inline long do_strncpy_from_user(char *dst, const char __user *src, long
goto byte_at_a_time;
while (max >= sizeof(unsigned long)) {
- unsigned long c, v, rhs;
+ unsigned long c, data;
/* Fall back to byte-at-a-time if we get a page fault */
if (unlikely(__get_user(c,(unsigned long __user *)(src+res))))
break;
- rhs = c | low_bits;
- v = (c + high_bits) & ~rhs;
*(unsigned long *)(dst+res) = c;
- if (v) {
- v = (c & low_bits) + low_bits;
- v = ~(v | rhs);
- return res + find_zero(v);
+ if (has_zero(c, &data, &constants)) {
+ data = prep_zero_mask(c, data, &constants);
+ data = create_zero_mask(data);
+ return res + find_zero(data);
}
res += sizeof(unsigned long);
max -= sizeof(unsigned long);