mirrors/linux
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git synced 2025-12-27 11:06:41 -05:00
Code Issues Packages Projects Releases Wiki Activity

lib/crypto: x86/blake2s: Avoid writing back unchanged 'f' value

Browse Source 
Just before returning, blake2s_compress_ssse3() and
blake2s_compress_avx512() store updated values to the 'h', 't', and 'f'
fields of struct blake2s_ctx.  But 'f' is always unchanged (which is
correct; only the C code changes it).  So, there's no need to write to
'f'.  Use 64-bit stores (movq and vmovq) instead of 128-bit stores
(movdqu and vmovdqu) so that only 't' is written.

Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20251102234209.62133-6-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
This commit is contained in:
Eric Biggers
2025-11-02 15:42:08 -08:00
parent a7acd77ebd
commit cd5528621a
1 changed files with 2 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

4
lib/crypto/x86/blake2s-core.S
View File

@@ -193,7 +193,7 @@ SYM_FUNC_START(blake2s_compress_ssse3)
movdqu %xmm0,(CTX) // Store new h[0..3]
movdqu %xmm1,16(CTX) // Store new h[4..7]
movdqu %xmm14,32(CTX) // Store new t and f
movq %xmm14,32(CTX) // Store new t (f is unchanged)
RET
SYM_FUNC_END(blake2s_compress_ssse3)
@@ -287,7 +287,7 @@ SYM_FUNC_START(blake2s_compress_avx512)
vmovdqu %xmm0,(CTX) // Store new h[0..3]
vmovdqu %xmm1,16(CTX) // Store new h[4..7]
vmovdqu %xmm4,32(CTX) // Store new t and f
vmovq %xmm4,32(CTX) // Store new t (f is unchanged)
vzeroupper
RET
SYM_FUNC_END(blake2s_compress_avx512)