kexec_file: use SHA-256 library API instead of crypto_shash API

From: Eric Biggers <[email protected]>

This user of SHA-256 does not support any other algorithm, so the crypto_shash abstraction provides no value. Just use the SHA-256 library API instead, which is much simpler and easier to use.

Tested with '/sbin/kexec --kexec-file-syscall'.

---

This patch is targeting the mm tree for 6.16.

 kernel/Kconfig.kexec |  3 +-
 kernel/kexec_file.c  | 78 +++++++++-----------------------------------
 2 files changed, 16 insertions(+), 65 deletions(-)

index 4fa212909d699..7c0d934d0bd76 100644
@@ -36,12 +36,11 @@ config KEXEC
 	  made.
 
 config KEXEC_FILE
 	bool "Enable kexec file based system call"
 	depends on ARCH_SUPPORTS_KEXEC_FILE
-	select CRYPTO
-	select CRYPTO_SHA256
+	select CRYPTO_LIB_SHA256
 	select KEXEC_CORE
 	help
 	  This is new version of kexec system call. This system call is
 	  file based and takes file descriptors as system call argument
 	  for kernel and initramfs as opposed to list of segments as

base-commit: 33035b665157558254b3c21c3f049fd728e72368

2.49.0