On Sun, Nov 27, 2022 at 10:13 PM Jason A. Donenfeld <Jason@xxxxxxxxx> wrote: > > Hi Thomas, > > On Sat, Nov 26, 2022 at 12:08:41AM +0100, Thomas Gleixner wrote: > > Jason! > > > > On Thu, Nov 24 2022 at 17:55, Jason A. Donenfeld wrote: > > > +++ b/arch/x86/entry/vdso/vgetrandom-chacha.S > > > +/* > > > + * Very basic SSE2 implementation of ChaCha20. Produces a given positive number > > > + * of blocks of output with a nonce of 0, taking an input key and 8-byte > > > + * counter. Importantly does not spill to the stack. Its arguments are: > > > > Basic or not. > > Heh, FYI I didn't mean "basic" here as in "doesn't need a review", but > just that it's a straightforward technique and doesn't do any > complicated multiblock pyrotechnics (which frankly aren't really > needed). > > > This needs a Reviewed-by from someone who understands SSE2 > > and ChaCha20 before this can go anywhere near the x86 tree. > > No problem. I'll see to it that somebody qualified gives this a review. > I did look at this earlier. It looks fine. I would recommend changing + /* copy1,copy2 = key */ + movdqu 0x00(key),copy1 + movdqu 0x10(key),copy2 to + /* copy1,copy2 = key */ + movups 0x00(key),copy1 + movups 0x10(key),copy2 which has the same semantics, but saves a couple of code bytes. Likewise for + movdqu state0,0x00(output) + movdqu state1,0x10(output) + movdqu state2,0x20(output) + movdqu state3,0x30(output) Otherwise, Reviewed-by: Samuel Neves <sneves@xxxxxxxxx> # for vgetrandom-chacha.S
