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crypto: crct10dif-vpmsum - Fix missing preempt_disable() 

In crct10dif_vpmsum() we call enable_kernel_altivec() without first
disabling preemption, which is not allowed.

It used to be sufficient just to call pagefault_disable(), because that
also disabled preemption. But the two were decoupled in commit 8222dbe21e
("sched/preempt, mm/fault: Decouple preemption from the page fault
logic") in mid 2015.

The crct10dif-vpmsum code inherited this bug from the crc32c-vpmsum code
on which it was modelled.

So add the missing preempt_disable/enable(). We should also call
disable_kernel_fp(), although it does nothing by default, there is a
debug switch to make it active and all enables should be paired with
disables.

Fixes: b01df1c16c ("crypto: powerpc - Add CRC-T10DIF acceleration")
Acked-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Michael Ellerman 2017-04-20 15:35:09 +10:00 committed by Herbert Xu
parent a9943a0ad1
commit 0f89f6e188
1 changed files with 3 additions and 0 deletions
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3
arch/powerpc/crypto/crct10dif-vpmsum_glue.c
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@ -44,10 +44,13 @@ static u16 crct10dif_vpmsum(u16 crci, unsigned char const *p, size_t len)
if (len & ~VMX_ALIGN_MASK) {
crc <<= 16;
preempt_disable();
pagefault_disable();
enable_kernel_altivec();
crc = __crct10dif_vpmsum(crc, p, len & ~VMX_ALIGN_MASK);
disable_kernel_altivec();
pagefault_enable();
preempt_enable();
crc >>= 16;
}