diff options
| author | Keith Packard <keithp@keithp.com> | 2016-12-17 20:58:36 -0800 |
|---|---|---|
| committer | Bdale Garbee <bdale@gag.com> | 2017-01-25 12:21:43 -0700 |
| commit | fe25510fc23031f1a3c1b42edd37067d1989a9f6 (patch) | |
| tree | 3cdc98d2c3d1c8d9bd95045771be7d15226d246b /src/aes/ao_aes.c | |
| parent | 4163d88ed36ce8863218366f1fb504f7061a4ca5 (diff) | |
altos/arm: Align data so that gcc 5.4 doesn't do byte-accesses. Add -Wcast-align
Gcc 5.4.1 tracks alignment of data through assignments, so that a
uint32_t pointer which comes from byte-aligned uint8_t data:
extern uint8_t foo[];
uint32_t *q = (void *) foo;
Fetches and stores through this pointer are done bytewise. This is
slow (meh), but if q references a device register, things to bad very
quickly.
This patch works around this bug in the compiler by adding
__attribute__((aligned(4))) tags to some variables, or changing them
from uint8_t to uint32_t. Places doing this will now be caught as I've
added -Wcast-align to the compiler flags. That required adding (void
*) casts, after the relevant code was checked to make sure the
compiler could tell that the addresses were aligned.
Signed-off-by: Keith Packard <keithp@keithp.com>
Diffstat (limited to 'src/aes/ao_aes.c')
| -rw-r--r-- | src/aes/ao_aes.c | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/src/aes/ao_aes.c b/src/aes/ao_aes.c index a04174c6..fd90c5bf 100644 --- a/src/aes/ao_aes.c +++ b/src/aes/ao_aes.c @@ -359,10 +359,10 @@ void xrijndaelDecrypt(word32 block[], roundkey *rkk) #endif uint8_t ao_aes_mutex; -static uint8_t key[16]; +static word32 key[16/4]; static roundkey rkk; -static uint8_t iv[16]; +static word32 iv[16/4]; void ao_aes_set_mode(enum ao_aes_mode mode) @@ -389,10 +389,11 @@ ao_aes_run(__xdata uint8_t *in, __xdata uint8_t *out) { uint8_t i; + uint8_t *_iv = (uint8_t *) iv; for (i = 0; i < 16; i++) - iv[i] ^= in[i]; - xrijndaelEncrypt((word32 *) iv, &rkk); + _iv[i] ^= in[i]; + xrijndaelEncrypt(iv, &rkk); if (out) memcpy(out, iv, 16); } |