lib/crypto: mips/md5: Migrate optimized code into library

Instead of exposing the mips-optimized MD5 code via mips-specific
crypto_shash algorithms, instead just implement the md5_blocks() library
function.  This is much simpler, it makes the MD5 library functions be
mips-optimized, and it fixes the longstanding issue where the
mips-optimized MD5 code was disabled by default.  MD5 still remains
available through crypto_shash, but individual architectures no longer
need to handle it.

Note: to see the diff from arch/mips/cavium-octeon/crypto/octeon-md5.c
to lib/crypto/mips/md5.h, view this commit with 'git show -M10'.

Link: https://lore.kernel.org/r/20250805222855.10362-3-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>

2 files changed, 66 insertions, 0 deletions

diff --git a/lib/crypto/Kconfig b/lib/crypto/Kconfig
index e38e8ed779d8..7b4e47ce37bb 100644
--- a/lib/crypto/Kconfig
+++ b/lib/crypto/Kconfig
@@ -110,6 +110,7 @@ config CRYPTO_LIB_MD5
 config CRYPTO_LIB_MD5_ARCH
 	bool
 	depends on CRYPTO_LIB_MD5 && !UML
+	default y if MIPS && CPU_CAVIUM_OCTEON
 
 config CRYPTO_LIB_POLY1305_RSIZE
 	int
diff --git a/lib/crypto/mips/md5.h b/lib/crypto/mips/md5.h
new file mode 100644
index 000000000000..e08e28aeffa4
--- /dev/null
+++ b/lib/crypto/mips/md5.h
@@ -0,0 +1,65 @@
+/*
+ * Cryptographic API.
+ *
+ * MD5 Message Digest Algorithm (RFC1321).
+ *
+ * Adapted for OCTEON by Aaro Koskinen <aaro.koskinen@iki.fi>.
+ *
+ * Based on crypto/md5.c, which is:
+ *
+ * Derived from cryptoapi implementation, originally based on the
+ * public domain implementation written by Colin Plumb in 1993.
+ *
+ * Copyright (c) Cryptoapi developers.
+ * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ */
+
+#include <asm/octeon/crypto.h>
+#include <asm/octeon/octeon.h>
+
+/*
+ * We pass everything as 64-bit. OCTEON can handle misaligned data.
+ */
+
+static void md5_blocks(struct md5_block_state *state,
+		       const u8 *data, size_t nblocks)
+{
+	struct octeon_cop2_state cop2_state;
+	u64 *state64 = (u64 *)state;
+	unsigned long flags;
+
+	if (!octeon_has_crypto())
+		return md5_blocks_generic(state, data, nblocks);
+
+	cpu_to_le32_array(state->h, ARRAY_SIZE(state->h));
+
+	flags = octeon_crypto_enable(&cop2_state);
+	write_octeon_64bit_hash_dword(state64[0], 0);
+	write_octeon_64bit_hash_dword(state64[1], 1);
+
+	do {
+		const u64 *block = (const u64 *)data;
+
+		write_octeon_64bit_block_dword(block[0], 0);
+		write_octeon_64bit_block_dword(block[1], 1);
+		write_octeon_64bit_block_dword(block[2], 2);
+		write_octeon_64bit_block_dword(block[3], 3);
+		write_octeon_64bit_block_dword(block[4], 4);
+		write_octeon_64bit_block_dword(block[5], 5);
+		write_octeon_64bit_block_dword(block[6], 6);
+		octeon_md5_start(block[7]);
+
+		data += MD5_BLOCK_SIZE;
+	} while (--nblocks);
+
+	state64[0] = read_octeon_64bit_hash_dword(0);
+	state64[1] = read_octeon_64bit_hash_dword(1);
+	octeon_crypto_disable(&cop2_state, flags);
+
+	le32_to_cpu_array(state->h, ARRAY_SIZE(state->h));
+}