1// SPDX-License-Identifier: GPL-2.0
2/**
3 * GHASH routines supporting VMX instructions on the Power 8
4 *
5 * Copyright (C) 2015, 2019 International Business Machines Inc.
6 *
7 * Author: Marcelo Henrique Cerri <mhcerri@br.ibm.com>
8 *
9 * Extended by Daniel Axtens <dja@axtens.net> to replace the fallback
10 * mechanism. The new approach is based on arm64 code, which is:
11 *   Copyright (C) 2014 - 2018 Linaro Ltd. <ard.biesheuvel@linaro.org>
12 */
13
14#include <linux/types.h>
15#include <linux/err.h>
16#include <linux/crypto.h>
17#include <linux/delay.h>
18#include <asm/simd.h>
19#include <asm/switch_to.h>
20#include <crypto/aes.h>
21#include <crypto/ghash.h>
22#include <crypto/scatterwalk.h>
23#include <crypto/internal/hash.h>
24#include <crypto/internal/simd.h>
25#include <crypto/b128ops.h>
26
27void gcm_init_p8(u128 htable[16], const u64 Xi[2]);
28void gcm_gmult_p8(u64 Xi[2], const u128 htable[16]);
29void gcm_ghash_p8(u64 Xi[2], const u128 htable[16],
30		  const u8 *in, size_t len);
31
32struct p8_ghash_ctx {
33	/* key used by vector asm */
34	u128 htable[16];
35	/* key used by software fallback */
36	be128 key;
37};
38
39struct p8_ghash_desc_ctx {
40	u64 shash[2];
41	u8 buffer[GHASH_DIGEST_SIZE];
42	int bytes;
43};
44
45static int p8_ghash_init(struct shash_desc *desc)
46{
47	struct p8_ghash_desc_ctx *dctx = shash_desc_ctx(desc);
48
49	dctx->bytes = 0;
50	memset(dctx->shash, 0, GHASH_DIGEST_SIZE);
51	return 0;
52}
53
54static int p8_ghash_setkey(struct crypto_shash *tfm, const u8 *key,
55			   unsigned int keylen)
56{
57	struct p8_ghash_ctx *ctx = crypto_tfm_ctx(crypto_shash_tfm(tfm));
58
59	if (keylen != GHASH_BLOCK_SIZE)
60		return -EINVAL;
61
62	preempt_disable();
63	pagefault_disable();
64	enable_kernel_vsx();
65	gcm_init_p8(ctx->htable, (const u64 *) key);
66	disable_kernel_vsx();
67	pagefault_enable();
68	preempt_enable();
69
70	memcpy(&ctx->key, key, GHASH_BLOCK_SIZE);
71
72	return 0;
73}
74
75static inline void __ghash_block(struct p8_ghash_ctx *ctx,
76				 struct p8_ghash_desc_ctx *dctx)
77{
78	if (crypto_simd_usable()) {
79		preempt_disable();
80		pagefault_disable();
81		enable_kernel_vsx();
82		gcm_ghash_p8(dctx->shash, ctx->htable,
83				dctx->buffer, GHASH_DIGEST_SIZE);
84		disable_kernel_vsx();
85		pagefault_enable();
86		preempt_enable();
87	} else {
88		crypto_xor((u8 *)dctx->shash, dctx->buffer, GHASH_BLOCK_SIZE);
89		gf128mul_lle((be128 *)dctx->shash, &ctx->key);
90	}
91}
92
93static inline void __ghash_blocks(struct p8_ghash_ctx *ctx,
94				  struct p8_ghash_desc_ctx *dctx,
95				  const u8 *src, unsigned int srclen)
96{
97	if (crypto_simd_usable()) {
98		preempt_disable();
99		pagefault_disable();
100		enable_kernel_vsx();
101		gcm_ghash_p8(dctx->shash, ctx->htable,
102				src, srclen);
103		disable_kernel_vsx();
104		pagefault_enable();
105		preempt_enable();
106	} else {
107		while (srclen >= GHASH_BLOCK_SIZE) {
108			crypto_xor((u8 *)dctx->shash, src, GHASH_BLOCK_SIZE);
109			gf128mul_lle((be128 *)dctx->shash, &ctx->key);
110			srclen -= GHASH_BLOCK_SIZE;
111			src += GHASH_BLOCK_SIZE;
112		}
113	}
114}
115
116static int p8_ghash_update(struct shash_desc *desc,
117			   const u8 *src, unsigned int srclen)
118{
119	unsigned int len;
120	struct p8_ghash_ctx *ctx = crypto_tfm_ctx(crypto_shash_tfm(desc->tfm));
121	struct p8_ghash_desc_ctx *dctx = shash_desc_ctx(desc);
122
123	if (dctx->bytes) {
124		if (dctx->bytes + srclen < GHASH_DIGEST_SIZE) {
125			memcpy(dctx->buffer + dctx->bytes, src,
126				srclen);
127			dctx->bytes += srclen;
128			return 0;
129		}
130		memcpy(dctx->buffer + dctx->bytes, src,
131			GHASH_DIGEST_SIZE - dctx->bytes);
132
133		__ghash_block(ctx, dctx);
134
135		src += GHASH_DIGEST_SIZE - dctx->bytes;
136		srclen -= GHASH_DIGEST_SIZE - dctx->bytes;
137		dctx->bytes = 0;
138	}
139	len = srclen & ~(GHASH_DIGEST_SIZE - 1);
140	if (len) {
141		__ghash_blocks(ctx, dctx, src, len);
142		src += len;
143		srclen -= len;
144	}
145	if (srclen) {
146		memcpy(dctx->buffer, src, srclen);
147		dctx->bytes = srclen;
148	}
149	return 0;
150}
151
152static int p8_ghash_final(struct shash_desc *desc, u8 *out)
153{
154	int i;
155	struct p8_ghash_ctx *ctx = crypto_tfm_ctx(crypto_shash_tfm(desc->tfm));
156	struct p8_ghash_desc_ctx *dctx = shash_desc_ctx(desc);
157
158	if (dctx->bytes) {
159		for (i = dctx->bytes; i < GHASH_DIGEST_SIZE; i++)
160			dctx->buffer[i] = 0;
161		__ghash_block(ctx, dctx);
162		dctx->bytes = 0;
163	}
164	memcpy(out, dctx->shash, GHASH_DIGEST_SIZE);
165	return 0;
166}
167
168struct shash_alg p8_ghash_alg = {
169	.digestsize = GHASH_DIGEST_SIZE,
170	.init = p8_ghash_init,
171	.update = p8_ghash_update,
172	.final = p8_ghash_final,
173	.setkey = p8_ghash_setkey,
174	.descsize = sizeof(struct p8_ghash_desc_ctx)
175		+ sizeof(struct ghash_desc_ctx),
176	.base = {
177		 .cra_name = "ghash",
178		 .cra_driver_name = "p8_ghash",
179		 .cra_priority = 1000,
180		 .cra_blocksize = GHASH_BLOCK_SIZE,
181		 .cra_ctxsize = sizeof(struct p8_ghash_ctx),
182		 .cra_module = THIS_MODULE,
183	},
184};
185