diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/g10lib.h | 43 |
1 files changed, 42 insertions, 1 deletions
diff --git a/src/g10lib.h b/src/g10lib.h index c580c085..f1af399e 100644 --- a/src/g10lib.h +++ b/src/g10lib.h @@ -238,11 +238,52 @@ void _gcry_burn_stack (int bytes); #define wipememory2(_ptr,_set,_len) do { \ volatile char *_vptr=(volatile char *)(_ptr); \ size_t _vlen=(_len); \ - while(_vlen) { *_vptr=(_set); _vptr++; _vlen--; } \ + unsigned char _vset=(_set); \ + fast_wipememory2(_vptr,_vset,_vlen); \ + while(_vlen) { *_vptr=(_vset); _vptr++; _vlen--; } \ } while(0) #define wipememory(_ptr,_len) wipememory2(_ptr,0,_len) +/* Optimized fast_wipememory2 for i386 and x86-64 architechtures. Maybe leave + tail bytes unhandled, in which case tail bytes are handled by wipememory2. + */ +#if defined(__x86_64__) && __GNUC__ >= 4 +#define fast_wipememory2(_vptr,_vset,_vlen) do { \ + unsigned long long int _vset8 = _vset; \ + if (_vlen < 8) \ + break; \ + _vset8 *= 0x0101010101010101ULL; \ + do { \ + asm volatile("movq %[set], %[ptr]\n\t" \ + : /**/ \ + : [set] "Cr" (_vset8), \ + [ptr] "m" (*_vptr) \ + : "memory"); \ + _vlen -= 8; \ + _vptr += 8; \ + } while (_vlen >= 8); \ + } while (0) +#elif defined (__i386__) && SIZEOF_UNSIGNED_LONG == 4 && __GNUC__ >= 4 +#define fast_wipememory2(_ptr,_set,_len) do { \ + unsigned long _vset4 = _vset; \ + if (_vlen < 4) \ + break; \ + _vset4 *= 0x01010101; \ + do { \ + asm volatile("movl %[set], %[ptr]\n\t" \ + : /**/ \ + : [set] "Cr" (_vset4), \ + [ptr] "m" (*_vptr) \ + : "memory"); \ + _vlen -= 4; \ + _vptr += 4; \ + } while (_vlen >= 4); \ + } while (0) +#else +#define fast_wipememory2(_ptr,_set,_len) +#endif + /* Digit predicates. */ |