crypto: sha256 - support arch-optimized lib and expose through shash

As has been done for various other algorithms, rework the design of the
SHA-256 library to support arch-optimized implementations, and make
crypto/sha256.c expose both generic and arch-optimized shash algorithms
that wrap the library functions.

This allows users of the SHA-256 library functions to take advantage of
the arch-optimized code, and this makes it much simpler to integrate
SHA-256 for each architecture.

Note that sha256_base.h is not used in the new design.  It will be
removed once all the architecture-specific code has been updated.

Move the generic block function into its own module to avoid a circular
dependency from libsha256.ko => sha256-$ARCH.ko => libsha256.ko.

Signed-off-by: Eric Biggers <ebiggers@google.com>

Add export and import functions to maintain existing export format.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 28 insertions, 0 deletions

diff --git a/include/crypto/internal/sha2.h b/include/crypto/internal/sha2.h
new file mode 100644
index 000000000000..d641c67abcbc
--- /dev/null
+++ b/include/crypto/internal/sha2.h
@@ -0,0 +1,28 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef _CRYPTO_INTERNAL_SHA2_H
+#define _CRYPTO_INTERNAL_SHA2_H
+
+#include <crypto/sha2.h>
+
+void sha256_update_generic(struct sha256_state *sctx,
+			   const u8 *data, size_t len);
+void sha256_final_generic(struct sha256_state *sctx,
+			  u8 out[SHA256_DIGEST_SIZE]);
+void sha224_final_generic(struct sha256_state *sctx,
+			  u8 out[SHA224_DIGEST_SIZE]);
+
+#if IS_ENABLED(CONFIG_CRYPTO_ARCH_HAVE_LIB_SHA256)
+bool sha256_is_arch_optimized(void);
+#else
+static inline bool sha256_is_arch_optimized(void)
+{
+	return false;
+}
+#endif
+void sha256_blocks_generic(u32 state[SHA256_STATE_WORDS],
+			   const u8 *data, size_t nblocks);
+void sha256_blocks_arch(u32 state[SHA256_STATE_WORDS],
+			const u8 *data, size_t nblocks);
+
+#endif /* _CRYPTO_INTERNAL_SHA2_H */