Re: [PATCH 1/2] PBL: add pbl_sha256()

[Lucas Stach <l.stach@pengutronix.de>]

Am Donnerstag, dem 09.07.2026 um 13:14 +0200 schrieb Sascha Hauer:
> The PBL open-codes SHA-256 as sha256_init()/sha256_update()/sha256_final()
> wherever it needs to hash a blob, which always uses the generic C transform.
> Add pbl_sha256(), a one-shot helper that hides this behind a single call and
> is free to pick the best transform available in the PBL. For now it only
> wraps the generic C implementation; an accelerated path is added on top in a
> later commit.
> 
> Convert pbl_barebox_verify() in pbl/decomp.c to the new helper as the first
> user.
> 
> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
> ---
>  include/crypto/pbl-sha.h |  4 ++++
>  pbl/Makefile             |  1 +
>  pbl/decomp.c             |  6 +-----
>  pbl/sha256.c             | 25 +++++++++++++++++++++++++
>  4 files changed, 31 insertions(+), 5 deletions(-)
> 
> diff --git a/include/crypto/pbl-sha.h b/include/crypto/pbl-sha.h
> index 7d323ab479..2508448ab4 100644
> --- a/include/crypto/pbl-sha.h
> +++ b/include/crypto/pbl-sha.h
> @@ -3,6 +3,7 @@
>  
>  #define __PBL_SHA_H_
>  
> +#include <crypto/sha.h>
>  #include <digest.h>
>  #include <types.h>
>  
> @@ -10,4 +11,7 @@ int sha256_init(struct digest *desc);
>  int sha256_update(struct digest *desc, const void *data, unsigned long len);
>  int sha256_final(struct digest *desc, u8 *out);
>  
> +/* One-shot SHA-256 that picks the best transform available in the PBL. */
> +void pbl_sha256(const void *buf, size_t len, u8 out[SHA256_DIGEST_SIZE]);
> +
>  #endif /* __PBL-SHA_H_ */
> diff --git a/pbl/Makefile b/pbl/Makefile
> index 45cfbf5fba..4506f192fe 100644
> --- a/pbl/Makefile
> +++ b/pbl/Makefile
> @@ -6,6 +6,7 @@
>  pbl-y += misc.o
>  pbl-y += string.o
>  pbl-y += malloc.o
> +pbl-y += sha256.o
>  pbl-$(CONFIG_HAVE_IMAGE_COMPRESSION) += decomp.o
>  pbl-$(CONFIG_LIBFDT) += fdt.o
>  pbl-$(CONFIG_PBL_CONSOLE) += console.o
> diff --git a/pbl/decomp.c b/pbl/decomp.c
> index 1539a6b67e..2b3c35012f 100644
> --- a/pbl/decomp.c
> +++ b/pbl/decomp.c
> @@ -58,8 +58,6 @@ extern unsigned char sha_sum_end[];
>  int pbl_barebox_verify(const void *compressed_start, unsigned int len,
>  		       const void *hash, unsigned int hash_len)
>  {
> -	struct sha256_state sha_state = { 0 };
> -	struct digest d = { .ctx = &sha_state };
>  	char computed_hash[SHA256_DIGEST_SIZE];
>  	int i;
>  	const char *char_hash = hash;
> @@ -67,9 +65,7 @@ int pbl_barebox_verify(const void *compressed_start, unsigned int len,
>  	if (hash_len != SHA256_DIGEST_SIZE)
>  		return -1;
>  
> -	sha256_init(&d);
> -	sha256_update(&d, compressed_start, len);
> -	sha256_final(&d, computed_hash);
> +	pbl_sha256(compressed_start, len, computed_hash);
>  	if (IS_ENABLED(CONFIG_DEBUG_LL)) {
>  		puts_ll("CH ");
>  
> diff --git a/pbl/sha256.c b/pbl/sha256.c
> new file mode 100644
> index 0000000000..86e54f8a25
> --- /dev/null
> +++ b/pbl/sha256.c
> @@ -0,0 +1,25 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * pbl_sha256() - one-shot SHA-256 for the PBL, picking the best available
> + * transform (ARMv8 Crypto Extensions if present, else generic C).

This file isn't ARMv8 specific, so I don't really see why the comment
would reference a specific implementation.

> + */
> +
> +#include <common.h>
> +#include <crypto/sha.h>
> +#include <crypto/pbl-sha.h>
> +#include <digest.h>
> +
> +static void pbl_sha256_generic(const void *buf, size_t len, u8 *out)
> +{
> +	struct sha256_state state = { };
> +	struct digest d = { .ctx = &state, .length = SHA256_DIGEST_SIZE };
> +
> +	sha256_init(&d);
> +	sha256_update(&d, buf, len);
> +	sha256_final(&d, out);
> +}
> +
> +void pbl_sha256(const void *buf, size_t len, u8 out[SHA256_DIGEST_SIZE])

That's a weird way to write "u8 *out"...

> +{
> +	pbl_sha256_generic(buf, len, out);
> +}