Re: [PATCH v5 11/29] image: Use the correct checks for CRC32

["Alex G." <mr.nuke.me@gmail.com>]

On 9/25/21 8:43 PM, Simon Glass wrote:
> Add a host Kconfig for CRC32. With this we can use CONFIG_IS_ENABLED(CRC32)
> directly in the host build, so drop the unnecessary indirection.
> 
> Add a few more conditions to SPL_CRC32 to avoid build failures as well as
> TPL_CRC32. Also update hash.c to make crc32 optional and to actually take
> notice of SPL_CRC32.
> 
> Signed-off-by: Simon Glass <sjg@chromium.org>

I'm not entirely convinced, but it does make CRC32 more consistent with 
other hashes.

Reviewed-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>

> ---
> 
> Changes in v5:
> - Rebase to next
> - Use TOOLS_ instead of HOST_
> 
>   common/hash.c      | 13 ++++++++-----
>   common/spl/Kconfig | 13 ++++++++++++-
>   lib/Kconfig        |  5 +++++
>   lib/Makefile       |  4 +---
>   tools/Kconfig      |  5 +++++
>   5 files changed, 31 insertions(+), 9 deletions(-)
> 
> diff --git a/common/hash.c b/common/hash.c
> index e92f9a9594f..b4b01c193b6 100644
> --- a/common/hash.c
> +++ b/common/hash.c
> @@ -178,7 +178,7 @@ static int hash_finish_crc16_ccitt(struct hash_algo *algo, void *ctx,
>   	return 0;
>   }
>   
> -static int hash_init_crc32(struct hash_algo *algo, void **ctxp)
> +static int __maybe_unused hash_init_crc32(struct hash_algo *algo, void **ctxp)
>   {
>   	uint32_t *ctx = malloc(sizeof(uint32_t));
>   	*ctx = 0;
> @@ -186,15 +186,16 @@ static int hash_init_crc32(struct hash_algo *algo, void **ctxp)
>   	return 0;
>   }
>   
> -static int hash_update_crc32(struct hash_algo *algo, void *ctx,
> -			     const void *buf, unsigned int size, int is_last)
> +static int __maybe_unused hash_update_crc32(struct hash_algo *algo, void *ctx,
> +					    const void *buf, unsigned int size,
> +					    int is_last)
>   {
>   	*((uint32_t *)ctx) = crc32(*((uint32_t *)ctx), buf, size);
>   	return 0;
>   }
>   
> -static int hash_finish_crc32(struct hash_algo *algo, void *ctx, void *dest_buf,
> -			     int size)
> +static int __maybe_unused hash_finish_crc32(struct hash_algo *algo, void *ctx,
> +					    void *dest_buf, int size)
>   {
>   	if (size < algo->digest_size)
>   		return -1;
> @@ -311,6 +312,7 @@ static struct hash_algo hash_algo[] = {
>   		.hash_update	= hash_update_crc16_ccitt,
>   		.hash_finish	= hash_finish_crc16_ccitt,
>   	},
> +#if CONFIG_IS_ENABLED(CRC32)
>   	{
>   		.name		= "crc32",
>   		.digest_size	= 4,
> @@ -320,6 +322,7 @@ static struct hash_algo hash_algo[] = {
>   		.hash_update	= hash_update_crc32,
>   		.hash_finish	= hash_finish_crc32,
>   	},
> +#endif
>   };
>   
>   /* Try to minimize code size for boards that don't want much hashing */
> diff --git a/common/spl/Kconfig b/common/spl/Kconfig
> index 34f6fc2cfad..91bb6c89fb4 100644
> --- a/common/spl/Kconfig
> +++ b/common/spl/Kconfig
> @@ -419,7 +419,8 @@ config SYS_MMCSD_RAW_MODE_EMMC_BOOT_PARTITION
>   
>   config SPL_CRC32
>   	bool "Support CRC32"
> -	default y if SPL_LEGACY_IMAGE_SUPPORT
> +	default y if SPL_LEGACY_IMAGE_SUPPORT || SPL_EFI_PARTITION
> +	default y if SPL_ENV_SUPPORT || TPL_BLOBLIST
>   	help
>   	  Enable this to support CRC32 in uImages or FIT images within SPL.
>   	  This is a 32-bit checksum value that can be used to verify images.
> @@ -1419,6 +1420,16 @@ config TPL_BOOTROM_SUPPORT
>   	  BOOT_DEVICE_BOOTROM (or fall-through to the next boot device in the
>   	  boot device list, if not implemented for a given board)
>   
> +config TPL_CRC32
> +	bool "Support CRC32 in TPL"
> +	default y if TPL_ENV_SUPPORT || TPL_BLOBLIST
> +	help
> +	  Enable this to support CRC32 in uImages or FIT images within SPL.
> +	  This is a 32-bit checksum value that can be used to verify images.
> +	  For FIT images, this is the least secure type of checksum, suitable
> +	  for detected accidental image corruption. For secure applications you
> +	  should consider SHA1 or SHA256.
> +
>   config TPL_DRIVERS_MISC
>   	bool "Support misc drivers in TPL"
>   	help
> diff --git a/lib/Kconfig b/lib/Kconfig
> index 64765acfa61..70bf8e7a464 100644
> --- a/lib/Kconfig
> +++ b/lib/Kconfig
> @@ -496,6 +496,11 @@ config SPL_MD5
>   	  security applications, but it can be useful for providing a quick
>   	  checksum of a block of data.
>   
> +config CRC32
> +	def_bool y
> +	help
> +	  Enables CRC32 support in U-Boot. This is normally required.
> +
>   config CRC32C
>   	bool
>   
> diff --git a/lib/Makefile b/lib/Makefile
> index 9c0373e2955..c523bb74119 100644
> --- a/lib/Makefile
> +++ b/lib/Makefile
> @@ -99,9 +99,7 @@ obj-y += display_options.o
>   CFLAGS_display_options.o := $(if $(BUILD_TAG),-DBUILD_TAG='"$(BUILD_TAG)"')
>   obj-$(CONFIG_BCH) += bch.o
>   obj-$(CONFIG_MMC_SPI) += crc7.o
> -#ifndef CONFIG_TPL_BUILD
> -obj-y += crc32.o
> -#endif
> +obj-$(CONFIG_$(SPL_TPL_)CRC32) += crc32.o
>   obj-$(CONFIG_CRC32C) += crc32c.o
>   obj-y += ctype.o
>   obj-y += div64.o
> diff --git a/tools/Kconfig b/tools/Kconfig
> index 8685c800f93..91ce8ae3e51 100644
> --- a/tools/Kconfig
> +++ b/tools/Kconfig
> @@ -9,6 +9,11 @@ config MKIMAGE_DTC_PATH
>   	  some cases the system dtc may not support all required features
>   	  and the path to a different version should be given here.
>   
> +config TOOLS_CRC32
> +	def_bool y
> +	help
> +	  Enable CRC32 support in the tools builds
> +
>   config TOOLS_LIBCRYPTO
>   	bool "Use OpenSSL's libcrypto library for host tools"
>   	default y
>