[PATCH 4/5] Glue code for optmized Poly1305 implementation for ppc64le.

[Danny Tsen <dtsen@linux.ibm.com>]

Signed-off-by: Danny Tsen <dtsen@linux.ibm.com>
---
 arch/powerpc/crypto/poly1305-p10-glue.c | 186 ++++++++++++++++++++++++
 1 file changed, 186 insertions(+)
 create mode 100644 arch/powerpc/crypto/poly1305-p10-glue.c

diff --git a/arch/powerpc/crypto/poly1305-p10-glue.c b/arch/powerpc/crypto/poly1305-p10-glue.c
new file mode 100644
index 000000000000..b1800f7b6af8
--- /dev/null
+++ b/arch/powerpc/crypto/poly1305-p10-glue.c
@@ -0,0 +1,186 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Poly1305 authenticator algorithm, RFC7539.
+ *
+ * Copyright 2023- IBM Inc. All rights reserved.
+ */
+
+#include <crypto/algapi.h>
+#include <linux/crypto.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/jump_label.h>
+#include <crypto/internal/hash.h>
+#include <crypto/internal/poly1305.h>
+#include <crypto/internal/simd.h>
+#include <linux/cpufeature.h>
+#include <asm/unaligned.h>
+#include <asm/simd.h>
+#include <asm/switch_to.h>
+
+asmlinkage void poly1305_p10le_4blocks(void *h, const u8 *m, u32 mlen);
+asmlinkage void poly1305_64s(void *h, const u8 *m, u32 mlen, int highbit);
+asmlinkage void poly1305_emit_64(void *h, void *s, u8 *dst);
+
+static void vsx_begin(void)
+{
+	preempt_disable();
+	enable_kernel_vsx();
+}
+
+static void vsx_end(void)
+{
+	disable_kernel_vsx();
+	preempt_enable();
+}
+
+static int crypto_poly1305_p10_init(struct shash_desc *desc)
+{
+	struct poly1305_desc_ctx *dctx = shash_desc_ctx(desc);
+
+	poly1305_core_init(&dctx->h);
+	dctx->buflen = 0;
+	dctx->rset = 0;
+	dctx->sset = false;
+
+	return 0;
+}
+
+static unsigned int crypto_poly1305_setdctxkey(struct poly1305_desc_ctx *dctx,
+					       const u8 *inp, unsigned int len)
+{
+	unsigned int acc = 0;
+
+	if (unlikely(!dctx->sset)) {
+		if (!dctx->rset && len >= POLY1305_BLOCK_SIZE) {
+			struct poly1305_core_key *key = &dctx->core_r;
+
+			key->key.r64[0] = get_unaligned_le64(&inp[0]);
+			key->key.r64[1] = get_unaligned_le64(&inp[8]);
+			inp += POLY1305_BLOCK_SIZE;
+			len -= POLY1305_BLOCK_SIZE;
+			acc += POLY1305_BLOCK_SIZE;
+			dctx->rset = 1;
+		}
+		if (len >= POLY1305_BLOCK_SIZE) {
+			dctx->s[0] = get_unaligned_le32(&inp[0]);
+			dctx->s[1] = get_unaligned_le32(&inp[4]);
+			dctx->s[2] = get_unaligned_le32(&inp[8]);
+			dctx->s[3] = get_unaligned_le32(&inp[12]);
+			acc += POLY1305_BLOCK_SIZE;
+			dctx->sset = true;
+		}
+	}
+	return acc;
+}
+
+static int crypto_poly1305_p10_update(struct shash_desc *desc,
+				      const u8 *src, unsigned int srclen)
+{
+	struct poly1305_desc_ctx *dctx = shash_desc_ctx(desc);
+	unsigned int bytes, used;
+
+	if (unlikely(dctx->buflen)) {
+		bytes = min(srclen, POLY1305_BLOCK_SIZE - dctx->buflen);
+		memcpy(dctx->buf + dctx->buflen, src, bytes);
+		src += bytes;
+		srclen -= bytes;
+		dctx->buflen += bytes;
+
+		if (dctx->buflen == POLY1305_BLOCK_SIZE) {
+			if (likely(!crypto_poly1305_setdctxkey(dctx, dctx->buf,
+							       POLY1305_BLOCK_SIZE))) {
+				vsx_begin();
+				poly1305_64s(&dctx->h, dctx->buf,
+						  POLY1305_BLOCK_SIZE, 1);
+				vsx_end();
+			}
+			dctx->buflen = 0;
+		}
+	}
+
+	if (likely(srclen >= POLY1305_BLOCK_SIZE)) {
+		bytes = round_down(srclen, POLY1305_BLOCK_SIZE);
+		used = crypto_poly1305_setdctxkey(dctx, src, bytes);
+		if (likely(used)) {
+			srclen -= used;
+			src += used;
+		}
+		if (srclen >= POLY1305_BLOCK_SIZE*4) {
+			vsx_begin();
+			poly1305_p10le_4blocks(&dctx->h, src, srclen);
+			vsx_end();
+			src += srclen - (srclen % (POLY1305_BLOCK_SIZE * 4));
+			srclen %= POLY1305_BLOCK_SIZE * 4;
+		}
+		while (srclen >= POLY1305_BLOCK_SIZE) {
+			vsx_begin();
+			poly1305_64s(&dctx->h, src, POLY1305_BLOCK_SIZE, 1);
+			vsx_end();
+			srclen -= POLY1305_BLOCK_SIZE;
+			src += POLY1305_BLOCK_SIZE;
+		}
+	}
+
+	if (unlikely(srclen)) {
+		dctx->buflen = srclen;
+		memcpy(dctx->buf, src, srclen);
+	}
+
+	return 0;
+}
+
+static int crypto_poly1305_p10_final(struct shash_desc *desc, u8 *dst)
+{
+	struct poly1305_desc_ctx *dctx = shash_desc_ctx(desc);
+
+	if (unlikely(!dctx->sset))
+		return -ENOKEY;
+
+	if ((dctx->buflen)) {
+		dctx->buf[dctx->buflen++] = 1;
+		memset(dctx->buf + dctx->buflen, 0,
+		       POLY1305_BLOCK_SIZE - dctx->buflen);
+		vsx_begin();
+		poly1305_64s(&dctx->h, dctx->buf, POLY1305_BLOCK_SIZE, 0);
+		vsx_end();
+		dctx->buflen = 0;
+	}
+
+	poly1305_emit_64(&dctx->h, &dctx->s, dst);
+	return 0;
+}
+
+static struct shash_alg poly1305_alg = {
+	.digestsize	= POLY1305_DIGEST_SIZE,
+	.init		= crypto_poly1305_p10_init,
+	.update		= crypto_poly1305_p10_update,
+	.final		= crypto_poly1305_p10_final,
+	.descsize	= sizeof(struct poly1305_desc_ctx),
+	.base		= {
+		.cra_name		= "poly1305",
+		.cra_driver_name	= "poly1305-p10",
+		.cra_priority		= 300,
+		.cra_blocksize		= POLY1305_BLOCK_SIZE,
+		.cra_module		= THIS_MODULE,
+	},
+};
+
+static int __init poly1305_p10_init(void)
+{
+	return crypto_register_shash(&poly1305_alg);
+}
+
+static void __exit poly1305_p10_exit(void)
+{
+	crypto_unregister_shash(&poly1305_alg);
+}
+
+module_cpu_feature_match(PPC_MODULE_FEATURE_P10, poly1305_p10_init);
+module_exit(poly1305_p10_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Danny Tsen <dtsen@linux.ibm.com>");
+MODULE_DESCRIPTION("Optimized Poly1305 for P10");
+MODULE_ALIAS_CRYPTO("poly1305");
+MODULE_ALIAS_CRYPTO("poly1305-p10");
-- 
2.31.1