| Message ID | 20231022081100.123613-10-ebiggers@kernel.org (mailing list archive) |
|---|---|
| State | Accepted |
| Delegated to: | Herbert Xu |
| Headers | show |
| Series | crypto: reduce ahash API overhead | expand |
Le 22/10/2023 à 10:10, Eric Biggers a écrit : > From: Eric Biggers <ebiggers@google.com> > > The crypto API's support for alignmasks for ahash algorithms is nearly > useless, as its only effect is to cause the API to align the key and > result buffers. The drivers that happen to be specifying an alignmask > for ahash rarely actually need it. When they do, it's easily fixable, > especially considering that these buffers cannot be used for DMA. > > In preparation for removing alignmask support from ahash, this patch > makes the talitos driver no longer use it. This driver didn't actually > rely on it; it only writes to the result buffer in > common_nonsnoop_hash_unmap(), simply using memcpy(). And this driver's > "ahash_setkey()" function does not assume any alignment for the key > buffer. I can't really see the link between your explanation and commit c9cca7034b34 ("crypto: talitos - Align SEC1 accesses to 32 bits boundaries."). Was that commit wrong ? Christophe > > Signed-off-by: Eric Biggers <ebiggers@google.com> > --- > drivers/crypto/talitos.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/crypto/talitos.c b/drivers/crypto/talitos.c > index 4ca4fbd227bce..e8f710d87007b 100644 > --- a/drivers/crypto/talitos.c > +++ b/drivers/crypto/talitos.c > @@ -3252,21 +3252,21 @@ static struct talitos_crypto_alg *talitos_alg_alloc(struct device *dev, > dev_err(dev, "unknown algorithm type %d\n", t_alg->algt.type); > devm_kfree(dev, t_alg); > return ERR_PTR(-EINVAL); > } > > alg->cra_module = THIS_MODULE; > if (t_alg->algt.priority) > alg->cra_priority = t_alg->algt.priority; > else > alg->cra_priority = TALITOS_CRA_PRIORITY; > - if (has_ftr_sec1(priv)) > + if (has_ftr_sec1(priv) && t_alg->algt.type != CRYPTO_ALG_TYPE_AHASH) > alg->cra_alignmask = 3; > else > alg->cra_alignmask = 0; > alg->cra_ctxsize = sizeof(struct talitos_ctx); > alg->cra_flags |= CRYPTO_ALG_KERN_DRIVER_ONLY; > > t_alg->dev = dev; > > return t_alg; > }
On Wed, Nov 29, 2023 at 03:00:48PM +0000, Christophe Leroy wrote: > > > Le 22/10/2023 à 10:10, Eric Biggers a écrit : > > From: Eric Biggers <ebiggers@google.com> > > > > The crypto API's support for alignmasks for ahash algorithms is nearly > > useless, as its only effect is to cause the API to align the key and > > result buffers. The drivers that happen to be specifying an alignmask > > for ahash rarely actually need it. When they do, it's easily fixable, > > especially considering that these buffers cannot be used for DMA. > > > > In preparation for removing alignmask support from ahash, this patch > > makes the talitos driver no longer use it. This driver didn't actually > > rely on it; it only writes to the result buffer in > > common_nonsnoop_hash_unmap(), simply using memcpy(). And this driver's > > "ahash_setkey()" function does not assume any alignment for the key > > buffer. > > I can't really see the link between your explanation and commit > c9cca7034b34 ("crypto: talitos - Align SEC1 accesses to 32 bits > boundaries."). > > Was that commit wrong ? > > Christophe Commit c9cca7034b34 ("crypto: talitos - Align SEC1 accesses to 32 bits boundaries.") added an alignmask to all algorithm types: skcipher, aead, and ahash. The commit did not explain why it was needed for each algorithm type, and its true necessity may have varied by algorithm type. In the case of ahashes, the alignmask may have been needed originally, but commit 7a6eda5b8d9d ("crypto: talitos - fix hash result for VMAP_STACK") made it unnecessary. - Eric
diff --git a/drivers/crypto/talitos.c b/drivers/crypto/talitos.c index 4ca4fbd227bce..e8f710d87007b 100644 --- a/drivers/crypto/talitos.c +++ b/drivers/crypto/talitos.c @@ -3252,21 +3252,21 @@ static struct talitos_crypto_alg *talitos_alg_alloc(struct device *dev, dev_err(dev, "unknown algorithm type %d\n", t_alg->algt.type); devm_kfree(dev, t_alg); return ERR_PTR(-EINVAL); } alg->cra_module = THIS_MODULE; if (t_alg->algt.priority) alg->cra_priority = t_alg->algt.priority; else alg->cra_priority = TALITOS_CRA_PRIORITY; - if (has_ftr_sec1(priv)) + if (has_ftr_sec1(priv) && t_alg->algt.type != CRYPTO_ALG_TYPE_AHASH) alg->cra_alignmask = 3; else alg->cra_alignmask = 0; alg->cra_ctxsize = sizeof(struct talitos_ctx); alg->cra_flags |= CRYPTO_ALG_KERN_DRIVER_ONLY; t_alg->dev = dev; return t_alg; }