On Sun, Nov 27, 2022 at 10:39:27PM +0000, Samuel Neves wrote: > 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 Thanks for the review and for the suggestion. Will do. Jason
