lib/crypto: mips/sha1: Migrate optimized code into library

Instead of exposing the mips-optimized SHA-1 code via mips-specific
crypto_shash algorithms, instead just implement the sha1_blocks()
library function.  This is much simpler, it makes the SHA-1 library
functions be mips-optimized, and it fixes the longstanding issue where
the mips-optimized SHA-1 code was disabled by default.  SHA-1 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-sha1.c
to lib/crypto/mips/sha1.h, view this commit with 'git show -M10'.

Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20250712232329.818226-10-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>

2 files changed, 82 insertions, 0 deletions

diff --git a/lib/crypto/Kconfig b/lib/crypto/Kconfig
index 05cce143af31..7c9dc432fb42 100644
--- a/lib/crypto/Kconfig
+++ b/lib/crypto/Kconfig
@@ -148,6 +148,7 @@ config CRYPTO_LIB_SHA1_ARCH
 	depends on CRYPTO_LIB_SHA1 && !UML
 	default y if ARM
 	default y if ARM64 && KERNEL_MODE_NEON
+	default y if MIPS && CPU_CAVIUM_OCTEON
 
 config CRYPTO_LIB_SHA256
 	tristate
diff --git a/lib/crypto/mips/sha1.h b/lib/crypto/mips/sha1.h
new file mode 100644
index 000000000000..ba1965002e4a
--- /dev/null
+++ b/lib/crypto/mips/sha1.h
@@ -0,0 +1,81 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Cryptographic API.
+ *
+ * SHA1 Secure Hash Algorithm.
+ *
+ * Adapted for OCTEON by Aaro Koskinen <aaro.koskinen@iki.fi>.
+ *
+ * Based on crypto/sha1_generic.c, which is:
+ *
+ * Copyright (c) Alan Smithee.
+ * Copyright (c) Andrew McDonald <andrew@mcdonald.org.uk>
+ * Copyright (c) Jean-Francois Dive <jef@linuxbe.org>
+ */
+
+#include <asm/octeon/crypto.h>
+#include <asm/octeon/octeon.h>
+
+/*
+ * We pass everything as 64-bit. OCTEON can handle misaligned data.
+ */
+
+static void octeon_sha1_store_hash(struct sha1_block_state *state)
+{
+	u64 *hash = (u64 *)&state->h[0];
+	union {
+		u32 word[2];
+		u64 dword;
+	} hash_tail = { { state->h[4], } };
+
+	write_octeon_64bit_hash_dword(hash[0], 0);
+	write_octeon_64bit_hash_dword(hash[1], 1);
+	write_octeon_64bit_hash_dword(hash_tail.dword, 2);
+	memzero_explicit(&hash_tail.word[0], sizeof(hash_tail.word[0]));
+}
+
+static void octeon_sha1_read_hash(struct sha1_block_state *state)
+{
+	u64 *hash = (u64 *)&state->h[0];
+	union {
+		u32 word[2];
+		u64 dword;
+	} hash_tail;
+
+	hash[0]		= read_octeon_64bit_hash_dword(0);
+	hash[1]		= read_octeon_64bit_hash_dword(1);
+	hash_tail.dword	= read_octeon_64bit_hash_dword(2);
+	state->h[4]	= hash_tail.word[0];
+	memzero_explicit(&hash_tail.dword, sizeof(hash_tail.dword));
+}
+
+static void sha1_blocks(struct sha1_block_state *state,
+			const u8 *data, size_t nblocks)
+{
+	struct octeon_cop2_state cop2_state;
+	unsigned long flags;
+
+	if (!octeon_has_crypto())
+		return sha1_blocks_generic(state, data, nblocks);
+
+	flags = octeon_crypto_enable(&cop2_state);
+	octeon_sha1_store_hash(state);
+
+	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_sha1_start(block[7]);
+
+		data += SHA1_BLOCK_SIZE;
+	} while (--nblocks);
+
+	octeon_sha1_read_hash(state);
+	octeon_crypto_disable(&cop2_state, flags);
+}