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[common] fix invalid read from unaligned addresses (fixes #410)

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Geoffrey McRae 2021-01-20 23:18:08 +11:00
parent 6077dcc123
commit 428b498cca
1 changed files with 14 additions and 3 deletions
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17
common/src/framebuffer.c
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@ -58,8 +58,6 @@ bool framebuffer_read(const FrameBuffer * frame, void * restrict dst,
uint_least32_t rp = 0; uint_least32_t rp = 0;
size_t y = 0; size_t y = 0;
const size_t linewidth = width * bpp; const size_t linewidth = width * bpp;
const size_t blocks = linewidth / 64;
const size_t left = linewidth % 64;
while(y < height) while(y < height)
{ {
@ -77,8 +75,21 @@ bool framebuffer_read(const FrameBuffer * frame, void * restrict dst,
wp = atomic_load_explicit(&frame->wp, memory_order_acquire); wp = atomic_load_explicit(&frame->wp, memory_order_acquire);
} }
/* copy any unaligned bytes */
const uint8_t * src = frame->data + rp;
const size_t unaligned = (uintptr_t)src & 0xF;
if (unaligned)
{
memcpy(d, src, unaligned);
src += unaligned;
d += unaligned;
}
const size_t blocks = (linewidth - unaligned) / 64;
const size_t left = (linewidth - unaligned) % 64;
_mm_mfence(); _mm_mfence();
__m128i * restrict s = (__m128i *)(frame->data + rp); __m128i * restrict s = (__m128i *)src;
for(int i = 0; i < blocks; ++i) for(int i = 0; i < blocks; ++i)
{ {
__m128i *_d = (__m128i *)d; __m128i *_d = (__m128i *)d;