Re: [PATCH 19/20] lib/crypto: riscv/aes-ctr: Migrate optimized code into library

[Eric Biggers]

On Tue, Sep 22, 2026 at 07:44:01AM +0200, Karl Mehltretter wrote:
> On Sun, 20 Sep 2026 22:09:05 -0700 Eric Biggers <ebiggers@xxxxxxxxxx> wrote:
> > -// void aes_ctr32_crypt_zvkned_zvkb(const struct crypto_aes_ctx *key,
> > -//				    const u8 *in, u8 *out, size_t len,
> > -//				    u8 iv[16]);
> > +// void aes_ctr32_crypt_zvkned_zvkb(u8 *dst, const u8 *src, u32 len, u8 iv[16],
> > +//				    const struct aes_enckey *key);
> >  SYM_FUNC_START(aes_ctr32_crypt_zvkned_zvkb)
> 
> isn't this a sign extension problem on rv64? The psABI sign-extends
> 32-bit args, so for len >= 2G a2 comes in as 0xffffffff8xxxxxxx, and
> the asm uses it as a 64-bit length as is.
> 
> That would run off the end of both buffers.
> 
> Nothing passes that much in one call today, but aes_ctr_arch() only
> chunks down to 0xfffffff0 and aes_ctr() takes a size_t, so it is
> allowed. The old prototype was size_t and the caller zero-extended.

Yes, Sashiko found this too.  I'll probably make the assembly function
continue to take size_t.

- Eric