lib/crypto: sha256: Consolidate into single module

Consolidate the CPU-based SHA-256 code into a single module, following
what I did with SHA-512:

- Each arch now provides a header file lib/crypto/$(SRCARCH)/sha256.h,
  replacing lib/crypto/$(SRCARCH)/sha256.c.  The header defines
  sha256_blocks() and optionally sha256_mod_init_arch().  It is included
  by lib/crypto/sha256.c, and thus the code gets built into the single
  libsha256 module, with proper inlining and dead code elimination.

- sha256_blocks_generic() is moved from lib/crypto/sha256-generic.c into
  lib/crypto/sha256.c.  It's now a static function marked with
  __maybe_unused, so the compiler automatically eliminates it in any
  cases where it's not used.

- Whether arch-optimized SHA-256 is buildable is now controlled
  centrally by lib/crypto/Kconfig instead of by
  lib/crypto/$(SRCARCH)/Kconfig.  The conditions for enabling it remain
  the same as before, and it remains enabled by default.

- Any additional arch-specific translation units for the optimized
  SHA-256 code (such as assembly files) are now compiled by
  lib/crypto/Makefile instead of lib/crypto/$(SRCARCH)/Makefile.

Acked-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20250630160645.3198-13-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>

3 files changed, 7 insertions, 34 deletions

diff --git a/lib/crypto/sparc/Kconfig b/lib/crypto/sparc/Kconfig
deleted file mode 100644
index e5c3e4d3dba6..000000000000
--- a/lib/crypto/sparc/Kconfig
+++ /dev/null
@@ -1,8 +0,0 @@
-# SPDX-License-Identifier: GPL-2.0-only
-
-config CRYPTO_SHA256_SPARC64
-	tristate
-	depends on SPARC64
-	default CRYPTO_LIB_SHA256
-	select CRYPTO_ARCH_HAVE_LIB_SHA256
-	select CRYPTO_LIB_SHA256_GENERIC
diff --git a/lib/crypto/sparc/Makefile b/lib/crypto/sparc/Makefile
deleted file mode 100644
index 75ee244ad6f7..000000000000
--- a/lib/crypto/sparc/Makefile
+++ /dev/null
@@ -1,4 +0,0 @@
-# SPDX-License-Identifier: GPL-2.0-only
-
-obj-$(CONFIG_CRYPTO_SHA256_SPARC64) += sha256-sparc64.o
-sha256-sparc64-y := sha256.o sha256_asm.o
diff --git a/lib/crypto/sparc/sha256.c b/lib/crypto/sparc/sha256.h
index f41c109c1c18..1d10108eb195 100644
--- a/lib/crypto/sparc/sha256.c
+++ b/lib/crypto/sparc/sha256.h
@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: GPL-2.0-only
+/* SPDX-License-Identifier: GPL-2.0-only */
 /*
  * SHA-256 accelerated using the sparc64 sha256 opcodes
  *
@@ -8,51 +8,36 @@
  * SHA224 Support Copyright 2007 Intel Corporation <jonathan.lynch@intel.com>
  */
 
-#define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt
-
 #include <asm/elf.h>
 #include <asm/opcodes.h>
 #include <asm/pstate.h>
-#include <crypto/internal/sha2.h>
-#include <linux/kernel.h>
-#include <linux/module.h>
 
 static __ro_after_init DEFINE_STATIC_KEY_FALSE(have_sha256_opcodes);
 
 asmlinkage void sha256_sparc64_transform(struct sha256_block_state *state,
 					 const u8 *data, size_t nblocks);
 
-void sha256_blocks_arch(struct sha256_block_state *state,
-			const u8 *data, size_t nblocks)
+static void sha256_blocks(struct sha256_block_state *state,
+			  const u8 *data, size_t nblocks)
 {
 	if (static_branch_likely(&have_sha256_opcodes))
 		sha256_sparc64_transform(state, data, nblocks);
 	else
 		sha256_blocks_generic(state, data, nblocks);
 }
-EXPORT_SYMBOL_GPL(sha256_blocks_arch);
 
-static int __init sha256_sparc64_mod_init(void)
+#define sha256_mod_init_arch sha256_mod_init_arch
+static inline void sha256_mod_init_arch(void)
 {
 	unsigned long cfr;
 
 	if (!(sparc64_elf_hwcap & HWCAP_SPARC_CRYPTO))
-		return 0;
+		return;
 
 	__asm__ __volatile__("rd %%asr26, %0" : "=r" (cfr));
 	if (!(cfr & CFR_SHA256))
-		return 0;
+		return;
 
 	static_branch_enable(&have_sha256_opcodes);
 	pr_info("Using sparc64 sha256 opcode optimized SHA-256/SHA-224 implementation\n");
-	return 0;
 }
-subsys_initcall(sha256_sparc64_mod_init);
-
-static void __exit sha256_sparc64_mod_exit(void)
-{
-}
-module_exit(sha256_sparc64_mod_exit);
-
-MODULE_LICENSE("GPL");
-MODULE_DESCRIPTION("SHA-256 accelerated using the sparc64 sha256 opcodes");