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| author | Mathias Krause <minipli@googlemail.com> | 2014-03-24 17:10:38 +0100 |
|---|---|---|
| committer | Herbert Xu <herbert@gondor.apana.org.au> | 2014-03-25 20:25:43 +0800 |
| commit | 6c8c17cc7a8806dde074d7c0bf4d519dd4d028c5 (patch) | |
| tree | d391a0579378dbdd4de40f441bb94d0e579811ff /arch/x86/crypto | |
| parent | 6ca5afb8c26991cf4f13a8bcca870ec2a9522bf7 (diff) | |
| download | linux-6c8c17cc7a8806dde074d7c0bf4d519dd4d028c5.tar.gz linux-6c8c17cc7a8806dde074d7c0bf4d519dd4d028c5.tar.bz2 linux-6c8c17cc7a8806dde074d7c0bf4d519dd4d028c5.zip | |
crypto: x86/sha1 - fix stack alignment of AVX2 variant
The AVX2 implementation might waste up to a page of stack memory because
of a wrong alignment calculation. This will, in the worst case, increase
the stack usage of sha1_transform_avx2() alone to 5.4 kB -- way to big
for a kernel function. Even worse, it might also allocate *less* bytes
than needed if the stack pointer is already aligned bacause in that case
the 'sub %rbx, %rsp' is effectively moving the stack pointer upwards,
not downwards.
Fix those issues by changing and simplifying the alignment calculation
to use a 32 byte alignment, the alignment really needed.
Cc: Chandramouli Narayanan <mouli@linux.intel.com>
Signed-off-by: Mathias Krause <minipli@googlemail.com>
Reviewed-by: H. Peter Anvin <hpa@linux.intel.com>
Reviewed-by: Marek Vasut <marex@denx.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'arch/x86/crypto')
| -rw-r--r-- | arch/x86/crypto/sha1_avx2_x86_64_asm.S | 7 |
1 files changed, 2 insertions, 5 deletions
diff --git a/arch/x86/crypto/sha1_avx2_x86_64_asm.S b/arch/x86/crypto/sha1_avx2_x86_64_asm.S index 4f348544d132..bacac22b20c2 100644 --- a/arch/x86/crypto/sha1_avx2_x86_64_asm.S +++ b/arch/x86/crypto/sha1_avx2_x86_64_asm.S @@ -636,9 +636,7 @@ _loop3: /* Align stack */ mov %rsp, %rbx - and $(0x1000-1), %rbx - sub $(8+32), %rbx - sub %rbx, %rsp + and $~(0x20-1), %rsp push %rbx sub $RESERVE_STACK, %rsp @@ -665,8 +663,7 @@ _loop3: avx2_zeroupper add $RESERVE_STACK, %rsp - pop %rbx - add %rbx, %rsp + pop %rsp pop %r15 pop %r14 |