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authorAl Viro <viro@zeniv.linux.org.uk>2017-03-19 20:07:21 +0100
committerAl Viro <viro@zeniv.linux.org.uk>2017-03-29 00:23:29 +0200
commit07f78b308984042dde424191ab8f3237bcf6a0d1 (patch)
treef880c01d0cc055995c5dec7b02efbd56fd2b6755 /arch/cris
parentcris: switch to generic extable.h (diff)
downloadlinux-07f78b308984042dde424191ab8f3237bcf6a0d1.tar.xz
linux-07f78b308984042dde424191ab8f3237bcf6a0d1.zip
cris: don't rely upon __copy_user_zeroing() zeroing the tail
we want to get rid of it; unfortunately, it's tangled as hell, so it'll take many steps, more's the pity. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'arch/cris')
-rw-r--r--arch/cris/include/asm/uaccess.h16
1 files changed, 9 insertions, 7 deletions
diff --git a/arch/cris/include/asm/uaccess.h b/arch/cris/include/asm/uaccess.h
index f62f546720a9..c8858e15d709 100644
--- a/arch/cris/include/asm/uaccess.h
+++ b/arch/cris/include/asm/uaccess.h
@@ -338,14 +338,16 @@ static inline size_t clear_user(void __user *to, size_t n)
static inline size_t copy_from_user(void *to, const void __user *from, size_t n)
{
- if (unlikely(!access_ok(VERIFY_READ, from, n))) {
- memset(to, 0, n);
- return n;
+ size_t res = n;
+ if (likely(access_ok(VERIFY_READ, from, n))) {
+ if (__builtin_constant_p(n))
+ res = __constant_copy_from_user(to, from, n);
+ else
+ res = __copy_user_zeroing(to, from, n);
}
- if (__builtin_constant_p(n))
- return __constant_copy_from_user(to, from, n);
- else
- return __copy_user_zeroing(to, from, n);
+ if (unlikely(res))
+ memset(to + n - res , 0, res);
+ return res;
}
static inline size_t copy_to_user(void __user *to, const void *from, size_t n)