diff options
| author | Sanrio Alvares <salvares@codeaurora.org> | 2016-02-08 18:42:08 -0800 |
|---|---|---|
| committer | Mister Oyster <oysterized@gmail.com> | 2017-04-11 10:59:17 +0200 |
| commit | 45246aeeab710cb51832d0549fc8ff8ebf048f34 (patch) | |
| tree | 9dfedbf33ec6908fe7934ba75261c4c7b99eb302 /lib/strncpy_from_user.c | |
| parent | 82832b1ca6bf78e365b67cf260f2a41c78ad2a93 (diff) | |
lib: align source before using optimized implementation
If the source is at the boundary of the VMA, loading one word at a
time can cause an alignment fault when the adjacent VMA is IO mapped.
Do byte-by-byte copy until source aligns to 8 bytes and then continue
with optimized version.
CRs-Fixed: 973724
Change-Id: I05e085597c58169fc6e275508a907029b9c7ec64
Signed-off-by: Sanrio Alvares <salvares@codeaurora.org>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
Diffstat (limited to 'lib/strncpy_from_user.c')
| -rw-r--r-- | lib/strncpy_from_user.c | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/lib/strncpy_from_user.c b/lib/strncpy_from_user.c index bb2b201d6..2cd748031 100644 --- a/lib/strncpy_from_user.c +++ b/lib/strncpy_from_user.c @@ -13,6 +13,8 @@ (((long) dst | (long) src) & (sizeof(long) - 1)) #endif +#define CHECK_ALIGN(v, a) ((((unsigned long)(v)) & ((a) - 1)) == 0) + /* * Do a strncpy, return length of string without final '\0'. * 'count' is the user-supplied count (return 'count' if we @@ -34,6 +36,21 @@ static inline long do_strncpy_from_user(char *dst, const char __user *src, long if (IS_UNALIGNED(src, dst)) goto byte_at_a_time; + /* Copy a byte at a time until we align to 8 bytes */ + while (max && (!CHECK_ALIGN(src + res, 8))) { + char c; + int ret; + + ret = __get_user(c, src + res); + if (ret) + return -ret; + dst[res] = c; + if (!c) + return res; + res++; + max--; + } + while (max >= sizeof(unsigned long)) { unsigned long c, data; |