[PATCH] ARM: crypto: fix function cast warnings

[Arnd Bergmann <arnd@xxxxxxxxxx>]

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);
      |                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Rework the sha256/sha512 code to instead go through a trivial helper
function to preserve the calling conventions.

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>
---
 arch/arm/crypto/sha256_glue.c | 18 ++++++++++--------
 arch/arm/crypto/sha512-glue.c | 11 ++++++++---
 2 files changed, 18 insertions(+), 11 deletions(-)

diff --git a/arch/arm/crypto/sha256_glue.c b/arch/arm/crypto/sha256_glue.c
index 433ee4ddce6c..d80448d96ab3 100644
--- a/arch/arm/crypto/sha256_glue.c
+++ b/arch/arm/crypto/sha256_glue.c
@@ -27,29 +27,31 @@
 asmlinkage void sha256_block_data_order(u32 *digest, const void *data,
 					unsigned int num_blks);
 
-int crypto_sha256_arm_update(struct shash_desc *desc, const u8 *data,
-			     unsigned int len)
+static void sha256_block_data_order_wrapper(struct sha256_state *sst, u8 const *src, int blocks)
 {
 	/* 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_block_data_order((u32 *)sst, src, blocks);
+}
+
+int crypto_sha256_arm_update(struct shash_desc *desc, const u8 *data,
+			     unsigned int len)
+{
+	return sha256_base_do_update(desc, data, len, sha256_block_data_order_wrapper);
 }
 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_wrapper);
 	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_wrapper);
 	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..1b2c9c0c8a5f 100644
--- a/arch/arm/crypto/sha512-glue.c
+++ b/arch/arm/crypto/sha512-glue.c
@@ -27,17 +27,22 @@ MODULE_ALIAS_CRYPTO("sha512-arm");
 
 asmlinkage void sha512_block_data_order(u64 *state, u8 const *src, int blocks);
 
+static void sha512_block_data_order_wrapper(struct sha512_state *sst, u8 const *src, int blocks)
+{
+	return sha512_block_data_order((u64 *)sst, src, 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);
+		sha512_block_data_order_wrapper);
 }
 
 static int sha512_arm_final(struct shash_desc *desc, u8 *out)
 {
 	sha512_base_do_finalize(desc,
-		(sha512_block_fn *)sha512_block_data_order);
+		sha512_block_data_order_wrapper);
 	return sha512_base_finish(desc, out);
 }
 
@@ -45,7 +50,7 @@ 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_block_data_order_wrapper);
 	return sha512_arm_final(desc, out);
 }
 
-- 
2.39.2