diff options
Diffstat (limited to 'include/linux/crypto.h')
| -rw-r--r-- | include/linux/crypto.h | 27 |
1 files changed, 14 insertions, 13 deletions
diff --git a/include/linux/crypto.h b/include/linux/crypto.h index f3c3a3b27fac..b164da5e129e 100644 --- a/include/linux/crypto.h +++ b/include/linux/crypto.h @@ -110,7 +110,6 @@ * crypto_aead_walksize() (with the remainder going at the end), no chunk * can cross a page boundary or a scatterlist element boundary. * ahash: - * - The result buffer must be aligned to the algorithm's alignmask. * - crypto_ahash_finup() must not be used unless the algorithm implements * ->finup() natively. */ @@ -278,18 +277,20 @@ struct compress_alg { * @cra_ctxsize: Size of the operational context of the transformation. This * value informs the kernel crypto API about the memory size * needed to be allocated for the transformation context. - * @cra_alignmask: Alignment mask for the input and output data buffer. The data - * buffer containing the input data for the algorithm must be - * aligned to this alignment mask. The data buffer for the - * output data must be aligned to this alignment mask. Note that - * the Crypto API will do the re-alignment in software, but - * only under special conditions and there is a performance hit. - * The re-alignment happens at these occasions for different - * @cra_u types: cipher -- For both input data and output data - * buffer; ahash -- For output hash destination buf; shash -- - * For output hash destination buf. - * This is needed on hardware which is flawed by design and - * cannot pick data from arbitrary addresses. + * @cra_alignmask: For cipher, skcipher, lskcipher, and aead algorithms this is + * 1 less than the alignment, in bytes, that the algorithm + * implementation requires for input and output buffers. When + * the crypto API is invoked with buffers that are not aligned + * to this alignment, the crypto API automatically utilizes + * appropriately aligned temporary buffers to comply with what + * the algorithm needs. (For scatterlists this happens only if + * the algorithm uses the skcipher_walk helper functions.) This + * misalignment handling carries a performance penalty, so it is + * preferred that algorithms do not set a nonzero alignmask. + * Also, crypto API users may wish to allocate buffers aligned + * to the alignmask of the algorithm being used, in order to + * avoid the API having to realign them. Note: the alignmask is + * not supported for hash algorithms and is always 0 for them. * @cra_priority: Priority of this transformation implementation. In case * multiple transformations with same @cra_name are available to * the Crypto API, the kernel will use the one with highest |