crypto: mips/poly1305 - incorporate OpenSSL/CRYPTOGAMS optimized implementation

This is a straight import of the OpenSSL/CRYPTOGAMS Poly1305 implementation for
MIPS authored by Andy Polyakov, a prior 64-bit only version of which has been
contributed by him to the OpenSSL project. The file 'poly1305-mips.pl' is taken
straight from this upstream GitHub repository [0] at commit
d22ade312a7af958ec955620b0d241cf42c37feb, and already contains all the changes
required to build it as part of a Linux kernel module.

[0] https://github.com/dot-asm/cryptogamsCo-developed-by: NAndy Polyakov <appro@cryptogams.org>
Signed-off-by: NAndy Polyakov <appro@cryptogams.org>
Co-developed-by: NRené van Dorst <opensource@vdorst.com>
Signed-off-by: NRené van Dorst <opensource@vdorst.com>
Signed-off-by: NArd Biesheuvel <ardb@kernel.org>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

arch/mips/crypto/Makefile

@@ -8,3 +8,17 @@ obj-$(CONFIG_CRYPTO_CRC32_MIPS) += crc32-mips.o
 obj-$(CONFIG_CRYPTO_CHACHA_MIPS) += chacha-mips.o
 chacha-mips-y := chacha-core.o chacha-glue.o
 AFLAGS_chacha-core.o += -O2 # needed to fill branch delay slots
+
+obj-$(CONFIG_CRYPTO_POLY1305_MIPS) += poly1305-mips.o
+poly1305-mips-y := poly1305-core.o poly1305-glue.o
+
+perlasm-flavour-$(CONFIG_CPU_MIPS32) := o32
+perlasm-flavour-$(CONFIG_CPU_MIPS64) := 64
+
+quiet_cmd_perlasm = PERLASM $@
+      cmd_perlasm = $(PERL) $(<) $(perlasm-flavour-y) $(@)
+
+$(obj)/poly1305-core.S: $(src)/poly1305-mips.pl FORCE
+	$(call if_changed,perlasm)
+
+targets += poly1305-core.S

arch/mips/crypto/poly1305-glue.c

+// SPDX-License-Identifier: GPL-2.0
+/*
+ * OpenSSL/Cryptogams accelerated Poly1305 transform for MIPS
+ *
+ * Copyright (C) 2019 Linaro Ltd. <ard.biesheuvel@linaro.org>
+ */
+
+#include <asm/unaligned.h>
+#include <crypto/algapi.h>
+#include <crypto/internal/hash.h>
+#include <crypto/internal/poly1305.h>
+#include <linux/cpufeature.h>
+#include <linux/crypto.h>
+#include <linux/module.h>
+
+asmlinkage void poly1305_init_mips(void *state, const u8 *key);
+asmlinkage void poly1305_blocks_mips(void *state, const u8 *src, u32 len, u32 hibit);
+asmlinkage void poly1305_emit_mips(void *state, __le32 *digest, const u32 *nonce);
+
+void poly1305_init_arch(struct poly1305_desc_ctx *dctx, const u8 *key)
+{
+	poly1305_init_mips(&dctx->h, key);
+	dctx->s[0] = get_unaligned_le32(key + 16);
+	dctx->s[1] = get_unaligned_le32(key + 20);
+	dctx->s[2] = get_unaligned_le32(key + 24);
+	dctx->s[3] = get_unaligned_le32(key + 28);
+	dctx->buflen = 0;
+}
+EXPORT_SYMBOL(poly1305_init_arch);
+
+static int mips_poly1305_init(struct shash_desc *desc)
+{
+	struct poly1305_desc_ctx *dctx = shash_desc_ctx(desc);
+
+	dctx->buflen = 0;
+	dctx->rset = 0;
+	dctx->sset = false;
+
+	return 0;
+}
+
+static void mips_poly1305_blocks(struct poly1305_desc_ctx *dctx, const u8 *src,
+				 u32 len, u32 hibit)
+{
+	if (unlikely(!dctx->sset)) {
+		if (!dctx->rset) {
+			poly1305_init_mips(&dctx->h, src);
+			src += POLY1305_BLOCK_SIZE;
+			len -= POLY1305_BLOCK_SIZE;
+			dctx->rset = 1;
+		}
+		if (len >= POLY1305_BLOCK_SIZE) {
+			dctx->s[0] = get_unaligned_le32(src +  0);
+			dctx->s[1] = get_unaligned_le32(src +  4);
+			dctx->s[2] = get_unaligned_le32(src +  8);
+			dctx->s[3] = get_unaligned_le32(src + 12);
+			src += POLY1305_BLOCK_SIZE;
+			len -= POLY1305_BLOCK_SIZE;
+			dctx->sset = true;
+		}
+		if (len < POLY1305_BLOCK_SIZE)
+			return;
+	}
+
+	len &= ~(POLY1305_BLOCK_SIZE - 1);
+
+	poly1305_blocks_mips(&dctx->h, src, len, hibit);
+}
+
+static int mips_poly1305_update(struct shash_desc *desc, const u8 *src,
+				unsigned int len)
+{
+	struct poly1305_desc_ctx *dctx = shash_desc_ctx(desc);
+
+	if (unlikely(dctx->buflen)) {
+		u32 bytes = min(len, POLY1305_BLOCK_SIZE - dctx->buflen);
+
+		memcpy(dctx->buf + dctx->buflen, src, bytes);
+		src += bytes;
+		len -= bytes;
+		dctx->buflen += bytes;
+
+		if (dctx->buflen == POLY1305_BLOCK_SIZE) {
+			mips_poly1305_blocks(dctx, dctx->buf, POLY1305_BLOCK_SIZE, 1);
+			dctx->buflen = 0;
+		}
+	}
+
+	if (likely(len >= POLY1305_BLOCK_SIZE)) {
+		mips_poly1305_blocks(dctx, src, len, 1);
+		src += round_down(len, POLY1305_BLOCK_SIZE);
+		len %= POLY1305_BLOCK_SIZE;
+	}
+
+	if (unlikely(len)) {
+		dctx->buflen = len;
+		memcpy(dctx->buf, src, len);
+	}
+	return 0;
+}
+
+void poly1305_update_arch(struct poly1305_desc_ctx *dctx, const u8 *src,
+			  unsigned int nbytes)
+{
+	if (unlikely(dctx->buflen)) {
+		u32 bytes = min(nbytes, POLY1305_BLOCK_SIZE - dctx->buflen);
+
+		memcpy(dctx->buf + dctx->buflen, src, bytes);
+		src += bytes;
+		nbytes -= bytes;
+		dctx->buflen += bytes;
+
+		if (dctx->buflen == POLY1305_BLOCK_SIZE) {
+			poly1305_blocks_mips(&dctx->h, dctx->buf,
+					     POLY1305_BLOCK_SIZE, 1);
+			dctx->buflen = 0;
+		}
+	}
+
+	if (likely(nbytes >= POLY1305_BLOCK_SIZE)) {
+		unsigned int len = round_down(nbytes, POLY1305_BLOCK_SIZE);
+
+		poly1305_blocks_mips(&dctx->h, src, len, 1);
+		src += len;
+		nbytes %= POLY1305_BLOCK_SIZE;
+	}
+
+	if (unlikely(nbytes)) {
+		dctx->buflen = nbytes;
+		memcpy(dctx->buf, src, nbytes);
+	}
+}
+EXPORT_SYMBOL(poly1305_update_arch);
+
+void poly1305_final_arch(struct poly1305_desc_ctx *dctx, u8 *dst)
+{
+	__le32 digest[4];
+	u64 f = 0;
+
+	if (unlikely(dctx->buflen)) {
+		dctx->buf[dctx->buflen++] = 1;
+		memset(dctx->buf + dctx->buflen, 0,
+		       POLY1305_BLOCK_SIZE - dctx->buflen);
+		poly1305_blocks_mips(&dctx->h, dctx->buf, POLY1305_BLOCK_SIZE, 0);
+	}
+
+	poly1305_emit_mips(&dctx->h, digest, dctx->s);
+
+	/* mac = (h + s) % (2^128) */
+	f = (f >> 32) + le32_to_cpu(digest[0]);
+	put_unaligned_le32(f, dst);
+	f = (f >> 32) + le32_to_cpu(digest[1]);
+	put_unaligned_le32(f, dst + 4);
+	f = (f >> 32) + le32_to_cpu(digest[2]);
+	put_unaligned_le32(f, dst + 8);
+	f = (f >> 32) + le32_to_cpu(digest[3]);
+	put_unaligned_le32(f, dst + 12);
+
+	*dctx = (struct poly1305_desc_ctx){};
+}
+EXPORT_SYMBOL(poly1305_final_arch);
+
+static int mips_poly1305_final(struct shash_desc *desc, u8 *dst)
+{
+	struct poly1305_desc_ctx *dctx = shash_desc_ctx(desc);
+
+	if (unlikely(!dctx->sset))
+		return -ENOKEY;
+
+	poly1305_final_arch(dctx, dst);
+	return 0;
+}
+
+static struct shash_alg mips_poly1305_alg = {
+	.init			= mips_poly1305_init,
+	.update			= mips_poly1305_update,
+	.final			= mips_poly1305_final,
+	.digestsize		= POLY1305_DIGEST_SIZE,
+	.descsize		= sizeof(struct poly1305_desc_ctx),
+
+	.base.cra_name		= "poly1305",
+	.base.cra_driver_name	= "poly1305-mips",
+	.base.cra_priority	= 200,
+	.base.cra_blocksize	= POLY1305_BLOCK_SIZE,
+	.base.cra_module	= THIS_MODULE,
+};
+
+static int __init mips_poly1305_mod_init(void)
+{
+	return crypto_register_shash(&mips_poly1305_alg);
+}
+
+static void __exit mips_poly1305_mod_exit(void)
+{
+	crypto_unregister_shash(&mips_poly1305_alg);
+}
+
+module_init(mips_poly1305_mod_init);
+module_exit(mips_poly1305_mod_exit);
+
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS_CRYPTO("poly1305");
+MODULE_ALIAS_CRYPTO("poly1305-mips");

crypto/Kconfig

@@ -724,6 +724,11 @@ config CRYPTO_POLY1305_X86_64
 	  in IETF protocols. This is the x86_64 assembler implementation using SIMD
 	  instructions.
 
+config CRYPTO_POLY1305_MIPS
+	tristate "Poly1305 authenticator algorithm (MIPS optimized)"
+	depends on CPU_MIPS32 || (CPU_MIPS64 && 64BIT)
+	select CRYPTO_ARCH_HAVE_LIB_POLY1305
+
 config CRYPTO_MD4
 	tristate "MD4 digest algorithm"
 	select CRYPTO_HASH

lib/crypto/Kconfig

@@ -39,6 +39,7 @@ config CRYPTO_LIB_DES
 
 config CRYPTO_LIB_POLY1305_RSIZE
 	int
+	default 2 if MIPS
 	default 4 if X86_64
 	default 9 if ARM || ARM64
 	default 1