| Message ID | 20220111181037.632969-1-Jason@zx2c4.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | reduce code size from blake2s on m68k and other small platforms | expand |
Hi, Geert emailed me this afternoon concerned about blake2s codesize on m68k and other small systems. We identified two effective ways of chopping down the size. One of them moves some wireguard-specific things into wireguard proper. The other one adds a slower codepath for small machines to blake2s. This worked, and was v1 of this patchset, but I wasn't so much of a fan. Then someone pointed out that the generic C SHA-1 implementation is still unrolled, which is a *lot* of extra code. Simply rerolling that saves about as much as v1 did. So, we instead do that in this patchset. SHA-1 is being phased out, and soon it won't be included at all (hopefully). And nothing performance-oriented has anything to do with it anyway. The result of these two patches mitigates Geert's feared code size increase for 5.17. v3 improves on v2 by making the re-rolling of SHA-1 much simpler, resulting in even larger code size reduction and much better performance. The reason I'm sending yet a third version in such a short amount of time is because the trick here feels obvious and substantial enough that I'd hate for Geert to waste time measuring the impact of the previous commit. Thanks, Jason Jason A. Donenfeld (2): lib/crypto: blake2s: move hmac construction into wireguard lib/crypto: sha1: re-roll loops to reduce code size drivers/net/wireguard/noise.c | 45 ++++++++++++++--- include/crypto/blake2s.h | 3 -- lib/crypto/blake2s-selftest.c | 31 ------------ lib/crypto/blake2s.c | 37 -------------- lib/sha1.c | 95 ++++++----------------------------- 5 files changed, 53 insertions(+), 158 deletions(-)