diff options
| author | Jeremy Compostella <jeremy.compostella@intel.com> | 2017-07-11 14:08:37 -0700 |
|---|---|---|
| committer | Julius Werner <jwerner@chromium.org> | 2017-07-13 18:16:15 +0000 |
| commit | 5b8987ae46512b5550d15fafd54b270ec913422d (patch) | |
| tree | 4f65b2ff44bbbd736ba976d75390679b5a4acdd8 /payloads/libpayload/libc | |
| parent | 4dc9fb026cf1834d5b99baee8f265ad6cebf8fc6 (diff) | |
libpayload: Support unaligned pointer for memcpy, memmove and memcmp
The memcpy(), memmove() and memcmp() functions use word by word
operations regardless of the pointer alignment. Depending on the
platform, this could lead to a crash.
This patch makes the memcpy(), memmove() or memcmp() operate byte per
byte if they are supplied with unaligned pointers.
Change-Id: I0b668739b7b58d47266f10f2dff2dc9cbf38577e
Signed-off-by: Jeremy Compostella <jeremy.compostella@intel.com>
Reviewed-on: https://review.coreboot.org/20535
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Nico Huber <nico.h@gmx.de>
Reviewed-by: Julius Werner <jwerner@chromium.org>
Diffstat (limited to 'payloads/libpayload/libc')
| -rw-r--r-- | payloads/libpayload/libc/memory.c | 34 |
1 files changed, 24 insertions, 10 deletions
diff --git a/payloads/libpayload/libc/memory.c b/payloads/libpayload/libc/memory.c index 1adfb3207f..2c44764edb 100644 --- a/payloads/libpayload/libc/memory.c +++ b/payloads/libpayload/libc/memory.c @@ -66,13 +66,17 @@ static void *default_memcpy(void *dst, const void *src, size_t n) size_t i; void *ret = dst; - for(i = 0; i < n / sizeof(unsigned long); i++) - ((unsigned long *)dst)[i] = ((unsigned long *)src)[i]; + if (IS_ALIGNED((uintptr_t)dst, sizeof(unsigned long)) && + IS_ALIGNED((uintptr_t)src, sizeof(unsigned long))) { + for (i = 0; i < n / sizeof(unsigned long); i++) + ((unsigned long *)dst)[i] = ((unsigned long *)src)[i]; - src += i * sizeof(unsigned long); - dst += i * sizeof(unsigned long); + src += i * sizeof(unsigned long); + dst += i * sizeof(unsigned long); + n -= i * sizeof(unsigned long); + } - for(i = 0; i < n % sizeof(unsigned long); i++) + for (i = 0; i < n; i++) ((u8 *)dst)[i] = ((u8 *)src)[i]; return ret; @@ -89,6 +93,13 @@ static void *default_memmove(void *dst, const void *src, size_t n) if (src > dst) return memcpy(dst, src, n); + if (!IS_ALIGNED((uintptr_t)dst, sizeof(unsigned long)) || + !IS_ALIGNED((uintptr_t)src, sizeof(unsigned long))) { + for (i = n - 1; i >= 0; i--) + ((u8 *)dst)[i] = ((u8 *)src)[i]; + return dst; + } + offs = n - (n % sizeof(unsigned long)); for (i = (n % sizeof(unsigned long)) - 1; i >= 0; i--) @@ -116,11 +127,14 @@ void *memmove(void *dst, const void *src, size_t n) static int default_memcmp(const void *s1, const void *s2, size_t n) { - size_t i; - - for (i = 0; i < n / sizeof(unsigned long); i++) - if (((unsigned long *)s1)[i] != ((unsigned long *)s2)[i]) - break; /* fall through to find differing byte */ + size_t i = 0; + const unsigned long *w1 = s1, *w2 = s2; + + if (IS_ALIGNED((uintptr_t)s1, sizeof(unsigned long)) && + IS_ALIGNED((uintptr_t)s2, sizeof(unsigned long))) + for (; i < n / sizeof(unsigned long); i++) + if (w1[i] != w2[i]) + break; /* fall through to find differing byte */ for (i *= sizeof(unsigned long); i < n; i++) if (((u8 *)s1)[i] != ((u8 *)s2)[i]) |