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powerpc: Use the new generic strncpy_from_user() and strnlen_user()

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This is much the same as for SPARC except that we can do the find_zero()
function more efficiently using the count-leading-zeroes instructions.
Tested on 32-bit and 64-bit PowerPC.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Paul Mackerras
2012-05-28 13:03:47 +10:00
committed by Linus Torvalds
parent 69ea640598
commit 1629372caa
5 changed files with 48 additions and 83 deletions
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41
arch/powerpc/include/asm/uaccess.h
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@@ -40,6 +40,8 @@
#define segment_eq(a, b) ((a).seg == (b).seg)
#define user_addr_max() (get_fs().seg)
#ifdef __powerpc64__
/*
* This check is sufficient because there is a large enough
@@ -453,42 +455,9 @@ static inline unsigned long clear_user(void __user *addr, unsigned long size)
return size;
}
extern int __strncpy_from_user(char *dst, const char __user *src, long count);
static inline long strncpy_from_user(char *dst, const char __user *src,
long count)
{
might_sleep();
if (likely(access_ok(VERIFY_READ, src, 1)))
return __strncpy_from_user(dst, src, count);
return -EFAULT;
}
/*
* Return the size of a string (including the ending 0)
*
* Return 0 for error
*/
extern int __strnlen_user(const char __user *str, long len, unsigned long top);
/*
* Returns the length of the string at str (including the null byte),
* or 0 if we hit a page we can't access,
* or something > len if we didn't find a null byte.
*
* The `top' parameter to __strnlen_user is to make sure that
* we can never overflow from the user area into kernel space.
*/
static inline int strnlen_user(const char __user *str, long len)
{
unsigned long top = current->thread.fs.seg;
if ((unsigned long)str > top)
return 0;
return __strnlen_user(str, len, top);
}
#define strlen_user(str) strnlen_user((str), 0x7ffffffe)
extern long strncpy_from_user(char *dst, const char __user *src, long count);
extern __must_check long strlen_user(const char __user *str);
extern __must_check long strnlen_user(const char __user *str, long n);
#endif /* __ASSEMBLY__ */
#endif /* __KERNEL__ */