Re: [PATCH] crypto: arm/sha1-neon - Fix clang function cast warnings

[Nick Desaulniers]

On Wed, Apr 19, 2023 at 2:27 AM Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> wrote:
>
> Instead of casting the function which upsets clang for some reason,
> change the assembly function siganture instead.

s/siganture/signature/

Thanks for the patch!  Perhaps worth noting in the commit message that
this fixes an instance of -Wcast-function-type-strict triggered for
W=1 builds, which helps us catch potential kCFI violations at compile
time rather than runtime.

After this patch, there's only 4 more users of the sha1_block_fn
typedef, consider if that typedef is a candidate for removal now?

Also, you should update the comment in
arch/arm/crypto/sha1-armv7-neon.S above the assembler implementation
on L288-289 to reflect this revised fn signature, in this patch.

>
> Reported-by: kernel test robot <lkp@xxxxxxxxx>
> Link: https://lore.kernel.org/oe-kbuild-all/202304081828.zjGcFUyE-lkp@xxxxxxxxx/
> Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
>
> diff --git a/arch/arm/crypto/sha1_neon_glue.c b/arch/arm/crypto/sha1_neon_glue.c
> index cfe36ae0f3f5..9c70b87e69f7 100644
> --- a/arch/arm/crypto/sha1_neon_glue.c
> +++ b/arch/arm/crypto/sha1_neon_glue.c
> @@ -26,8 +26,8 @@
>
>  #include "sha1.h"
>
> -asmlinkage void sha1_transform_neon(void *state_h, const char *data,
> -                                   unsigned int rounds);
> +asmlinkage void sha1_transform_neon(struct sha1_state *state_h,
> +                                   const u8 *data, int rounds);
>
>  static int sha1_neon_update(struct shash_desc *desc, const u8 *data,
>                           unsigned int len)
> @@ -39,8 +39,7 @@ static int sha1_neon_update(struct shash_desc *desc, const u8 *data,
>                 return sha1_update_arm(desc, data, len);
>
>         kernel_neon_begin();
> -       sha1_base_do_update(desc, data, len,
> -                           (sha1_block_fn *)sha1_transform_neon);
> +       sha1_base_do_update(desc, data, len, sha1_transform_neon);
>         kernel_neon_end();
>
>         return 0;
> @@ -54,9 +53,8 @@ static int sha1_neon_finup(struct shash_desc *desc, const u8 *data,
>
>         kernel_neon_begin();
>         if (len)
> -               sha1_base_do_update(desc, data, len,
> -                                   (sha1_block_fn *)sha1_transform_neon);
> -       sha1_base_do_finalize(desc, (sha1_block_fn *)sha1_transform_neon);
> +               sha1_base_do_update(desc, data, len, sha1_transform_neon);
> +       sha1_base_do_finalize(desc, sha1_transform_neon);
>         kernel_neon_end();
>
>         return sha1_base_finish(desc, out);
> --
> Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
> Home Page: http://gondor.apana.org.au/~herbert/
> PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
>


-- 
Thanks,
~Nick Desaulniers