Hi Bejamin: On Mon, Oct 23, 2006 at 05:50:20PM -0400, Benjamin Gilbert wrote: > This is a new CryptoAPI module containing an x86-optimized implementation of > SHA1, taken from Nettle.
Thanks for the patch! Sorry for the very late response. I just discovered this while cleaning up my mailbox :) > 1. Recognizing that arch/i386/crypto/sha1.c contains almost the same > functionality as crypto/sha1.c, I could abstract out common code between the > two implementations. However, given the length of the files in question, I > suspect the complexity isn't worth it. In-tree, AES uses duplicated code > between the asm and C versions, while Twofish pulls out common code into a > separate module. Considering the simplicity of sha1.c, I'd say that you should just duplicate it. > 2. Since the optimized part of the code is the SHA1 compression function, > and since crypto/sha1.c is just a wrapper around the compression function in > lib/sha1.c, I could eliminate the separate CryptoAPI module and switch the > kernel between the C and asm compression functions based on a config option > -- so that all SHA1 users get the optimized version, instead of just > CryptoAPI. There is an API issue though: the optimized code needs to > allocate its workspace on the stack for register-allocation reasons, and the > C version expects the caller to allocate a temporary buffer (to minimize the > number of times the workspace needs to be cleared when hashing several times > in a row). If the optimized code was used with the current API, the caller > would be doing a bunch of allocation and clearing for nothing. (Note: the > only direct users of lib/sha1.c right now are /dev/random and syncookies.) > > Which (if any) is the preferred approach? I think the best solution is to replace SHA_WORKSPACE_WORDS with an inline function/macro that returns zero for the optimised version. Cheers, -- Visit Openswan at http://www.openswan.org/ Email: Herbert Xu ~{PmV>HI~} <[EMAIL PROTECTED]> Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
