Re: [PATCH] [v2] ARM: crypto: fix function cast warnings

[Ard Biesheuvel]

On Tue, 13 Feb 2024 at 14:50, Arnd Bergmann <arnd@xxxxxxxxxx> wrote:
>
> From: Arnd Bergmann <arnd@xxxxxxxx>
>
> clang-16 warns about casting between incompatible function types:
>
> arch/arm/crypto/sha256_glue.c:37:5: error: cast from 'void (*)(u32 *, const void *, unsigned int)' (aka 'void (*)(unsigned int *, const void *, unsigned int)') to 'sha256_block_fn *' (aka 'void (*)(struct sha256_state *, const unsigned char *, int)') converts to incompatible function type [-Werror,-Wcast-function-type-strict]
>    37 |                                 (sha256_block_fn *)sha256_block_data_order);
>       |                                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> arch/arm/crypto/sha512-glue.c:34:3: error: cast from 'void (*)(u64 *, const u8 *, int)' (aka 'void (*)(unsigned long long *, const unsigned char *, int)') to 'sha512_block_fn *' (aka 'void (*)(struct sha512_state *, const unsigned char *, int)') converts to incompatible function type [-Werror,-Wcast-function-type-strict]
>    34 |                 (sha512_block_fn *)sha512_block_data_order);
>       |                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> Fix the prototypes for the assembler functions to match the typedef.
> The code already relies on the digest being the first part of the
> state structure, so there is no change in behavior.
>
> Fixes: c80ae7ca3726 ("crypto: arm/sha512 - accelerated SHA-512 using ARM generic ASM and NEON")
> Fixes: b59e2ae3690c ("crypto: arm/sha256 - move SHA-224/256 ASM/NEON implementation to base layer")
> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
> ---
> v2: rewrite change as suggested by Herbert Xu.
> ---
>  arch/arm/crypto/sha256_glue.c | 13 +++++--------
>  arch/arm/crypto/sha512-glue.c | 12 +++++-------
>  2 files changed, 10 insertions(+), 15 deletions(-)
>

Reviewed-by: Ard Biesheuvel <ardb@xxxxxxxxxx>

> diff --git a/arch/arm/crypto/sha256_glue.c b/arch/arm/crypto/sha256_glue.c
> index 433ee4ddce6c..f85933fdec75 100644
> --- a/arch/arm/crypto/sha256_glue.c
> +++ b/arch/arm/crypto/sha256_glue.c
> @@ -24,8 +24,8 @@
>
>  #include "sha256_glue.h"
>
> -asmlinkage void sha256_block_data_order(u32 *digest, const void *data,
> -                                       unsigned int num_blks);
> +asmlinkage void sha256_block_data_order(struct sha256_state *state,
> +                                       const u8 *data, int num_blks);
>
>  int crypto_sha256_arm_update(struct shash_desc *desc, const u8 *data,
>                              unsigned int len)
> @@ -33,23 +33,20 @@ int crypto_sha256_arm_update(struct shash_desc *desc, const u8 *data,
>         /* make sure casting to sha256_block_fn() is safe */
>         BUILD_BUG_ON(offsetof(struct sha256_state, state) != 0);
>
> -       return sha256_base_do_update(desc, data, len,
> -                               (sha256_block_fn *)sha256_block_data_order);
> +       return sha256_base_do_update(desc, data, len, sha256_block_data_order);
>  }
>  EXPORT_SYMBOL(crypto_sha256_arm_update);
>
>  static int crypto_sha256_arm_final(struct shash_desc *desc, u8 *out)
>  {
> -       sha256_base_do_finalize(desc,
> -                               (sha256_block_fn *)sha256_block_data_order);
> +       sha256_base_do_finalize(desc, sha256_block_data_order);
>         return sha256_base_finish(desc, out);
>  }
>
>  int crypto_sha256_arm_finup(struct shash_desc *desc, const u8 *data,
>                             unsigned int len, u8 *out)
>  {
> -       sha256_base_do_update(desc, data, len,
> -                             (sha256_block_fn *)sha256_block_data_order);
> +       sha256_base_do_update(desc, data, len, sha256_block_data_order);
>         return crypto_sha256_arm_final(desc, out);
>  }
>  EXPORT_SYMBOL(crypto_sha256_arm_finup);
> diff --git a/arch/arm/crypto/sha512-glue.c b/arch/arm/crypto/sha512-glue.c
> index 0635a65aa488..1be5bd498af3 100644
> --- a/arch/arm/crypto/sha512-glue.c
> +++ b/arch/arm/crypto/sha512-glue.c
> @@ -25,27 +25,25 @@ MODULE_ALIAS_CRYPTO("sha512");
>  MODULE_ALIAS_CRYPTO("sha384-arm");
>  MODULE_ALIAS_CRYPTO("sha512-arm");
>
> -asmlinkage void sha512_block_data_order(u64 *state, u8 const *src, int blocks);
> +asmlinkage void sha512_block_data_order(struct sha512_state *state,
> +                                       u8 const *src, int blocks);
>
>  int sha512_arm_update(struct shash_desc *desc, const u8 *data,
>                       unsigned int len)
>  {
> -       return sha512_base_do_update(desc, data, len,
> -               (sha512_block_fn *)sha512_block_data_order);
> +       return sha512_base_do_update(desc, data, len, sha512_block_data_order);
>  }
>
>  static int sha512_arm_final(struct shash_desc *desc, u8 *out)
>  {
> -       sha512_base_do_finalize(desc,
> -               (sha512_block_fn *)sha512_block_data_order);
> +       sha512_base_do_finalize(desc, sha512_block_data_order);
>         return sha512_base_finish(desc, out);
>  }
>
>  int sha512_arm_finup(struct shash_desc *desc, const u8 *data,
>                      unsigned int len, u8 *out)
>  {
> -       sha512_base_do_update(desc, data, len,
> -               (sha512_block_fn *)sha512_block_data_order);
> +       sha512_base_do_update(desc, data, len, sha512_block_data_order);
>         return sha512_arm_final(desc, out);
>  }
>
> --
> 2.39.2
>