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| author | Chris Metcalf <cmetcalf@mellanox.com> | 2017-01-16 15:38:25 -0500 |
|---|---|---|
| committer | Chris Metcalf <cmetcalf@mellanox.com> | 2017-01-16 15:44:48 -0500 |
| commit | 502697713f4f129b602d7213253a9982ee1989f1 (patch) | |
| tree | 933c5eb4537e278df0cb0e2e664c40bc0afe6b38 | |
| parent | 4cb89c158124c27006903f10e309b09d5311053a (diff) | |
| download | glibc-502697713f4f129b602d7213253a9982ee1989f1.tar.gz glibc-502697713f4f129b602d7213253a9982ee1989f1.tar.xz glibc-502697713f4f129b602d7213253a9982ee1989f1.zip | |
tile: Check for pointer add overflow in memchr
As was done in b224637928e9, check for large size causing an overflow in the loop that walks over the array. Branching out of line here is the fastest approach for handling this problem, since tile can bundle the instructions to compute the branch test in parallel with doing the required memchr loop setup computation. Unfortunately, the existing saturated ops (e.g. tilegx addxsc) are all signed saturing ops, so don't help with unsigned saturation.
| -rw-r--r-- | ChangeLog | 4 | ||||
| -rw-r--r-- | sysdeps/tile/tilegx/memchr.c | 4 | ||||
| -rw-r--r-- | sysdeps/tile/tilepro/memchr.c | 4 |
3 files changed, 12 insertions, 0 deletions
diff --git a/ChangeLog b/ChangeLog index 5388306806..9498803f7f 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,5 +1,9 @@ 2017-01-16 Chris Metcalf <cmetcalf@mellanox.com> + * sysdeps/tile/tilegx/memchr.c (__memchr): Handle pointer + wrap-around. + * sysdeps/tile/tilepro/memchr.c (__memchr): Likewise. + * sysdeps/unix/sysv/linux/tile/ipc_priv.h: New file. 2016-01-14 Siddhesh Poyarekar <siddhesh@sourceware.org> diff --git a/sysdeps/tile/tilegx/memchr.c b/sysdeps/tile/tilegx/memchr.c index 34df19d231..7da0f79da2 100644 --- a/sysdeps/tile/tilegx/memchr.c +++ b/sysdeps/tile/tilegx/memchr.c @@ -51,6 +51,10 @@ __memchr (const void *s, int c, size_t n) /* Compute the address of the last byte. */ last_byte_ptr = (const char *) s + n - 1; + /* Handle possible addition overflow. */ + if (__glibc_unlikely ((uintptr_t) last_byte_ptr < (uintptr_t) s)) + last_byte_ptr = (const char *) UINTPTR_MAX; + /* Compute the address of the word containing the last byte. */ last_word_ptr = (const uint64_t *) ((uintptr_t) last_byte_ptr & -8); diff --git a/sysdeps/tile/tilepro/memchr.c b/sysdeps/tile/tilepro/memchr.c index 1848a9cadb..fba1f70c2c 100644 --- a/sysdeps/tile/tilepro/memchr.c +++ b/sysdeps/tile/tilepro/memchr.c @@ -51,6 +51,10 @@ __memchr (const void *s, int c, size_t n) /* Compute the address of the last byte. */ last_byte_ptr = (const char *) s + n - 1; + /* Handle possible addition overflow. */ + if (__glibc_unlikely ((uintptr_t) last_byte_ptr < (uintptr_t) s)) + last_byte_ptr = (const char *) UINTPTR_MAX; + /* Compute the address of the word containing the last byte. */ last_word_ptr = (const uint32_t *) ((uintptr_t) last_byte_ptr & -4); |