1// SPDX-License-Identifier: GPL-2.0-only
  2#include <linux/crc32.h>
  3#include <crypto/internal/hash.h>
  4#include <crypto/internal/simd.h>
  5#include <linux/init.h>
  6#include <linux/module.h>
  7#include <linux/string.h>
  8#include <linux/kernel.h>
  9#include <linux/cpufeature.h>
 10#include <asm/simd.h>
 11#include <asm/switch_to.h>
 12
 13#define CHKSUM_BLOCK_SIZE	1
 14#define CHKSUM_DIGEST_SIZE	4
 15
 16#define VMX_ALIGN		16
 17#define VMX_ALIGN_MASK		(VMX_ALIGN-1)
 18
 19#define VECTOR_BREAKPOINT	512
 20
 21u32 __crc32c_vpmsum(u32 crc, unsigned char const *p, size_t len);
 22
 23static u32 crc32c_vpmsum(u32 crc, unsigned char const *p, size_t len)
 24{
 25	unsigned int prealign;
 26	unsigned int tail;
 27
 28	if (len < (VECTOR_BREAKPOINT + VMX_ALIGN) || !crypto_simd_usable())
 29		return __crc32c_le(crc, p, len);
 30
 31	if ((unsigned long)p & VMX_ALIGN_MASK) {
 32		prealign = VMX_ALIGN - ((unsigned long)p & VMX_ALIGN_MASK);
 33		crc = __crc32c_le(crc, p, prealign);
 34		len -= prealign;
 35		p += prealign;
 36	}
 37
 38	if (len & ~VMX_ALIGN_MASK) {
 39		preempt_disable();
 40		pagefault_disable();
 41		enable_kernel_altivec();
 42		crc = __crc32c_vpmsum(crc, p, len & ~VMX_ALIGN_MASK);
 43		disable_kernel_altivec();
 44		pagefault_enable();
 45		preempt_enable();
 46	}
 47
 48	tail = len & VMX_ALIGN_MASK;
 49	if (tail) {
 50		p += len & ~VMX_ALIGN_MASK;
 51		crc = __crc32c_le(crc, p, tail);
 52	}
 53
 54	return crc;
 55}
 56
 57static int crc32c_vpmsum_cra_init(struct crypto_tfm *tfm)
 58{
 59	u32 *key = crypto_tfm_ctx(tfm);
 60
 61	*key = ~0;
 62
 63	return 0;
 64}
 65
 66/*
 67 * Setting the seed allows arbitrary accumulators and flexible XOR policy
 68 * If your algorithm starts with ~0, then XOR with ~0 before you set
 69 * the seed.
 70 */
 71static int crc32c_vpmsum_setkey(struct crypto_shash *hash, const u8 *key,
 72			       unsigned int keylen)
 73{
 74	u32 *mctx = crypto_shash_ctx(hash);
 75
 76	if (keylen != sizeof(u32))
 77		return -EINVAL;
 78	*mctx = le32_to_cpup((__le32 *)key);
 79	return 0;
 80}
 81
 82static int crc32c_vpmsum_init(struct shash_desc *desc)
 83{
 84	u32 *mctx = crypto_shash_ctx(desc->tfm);
 85	u32 *crcp = shash_desc_ctx(desc);
 86
 87	*crcp = *mctx;
 88
 89	return 0;
 90}
 91
 92static int crc32c_vpmsum_update(struct shash_desc *desc, const u8 *data,
 93			       unsigned int len)
 94{
 95	u32 *crcp = shash_desc_ctx(desc);
 96
 97	*crcp = crc32c_vpmsum(*crcp, data, len);
 98
 99	return 0;
100}
101
102static int __crc32c_vpmsum_finup(u32 *crcp, const u8 *data, unsigned int len,
103				u8 *out)
104{
105	*(__le32 *)out = ~cpu_to_le32(crc32c_vpmsum(*crcp, data, len));
106
107	return 0;
108}
109
110static int crc32c_vpmsum_finup(struct shash_desc *desc, const u8 *data,
111			      unsigned int len, u8 *out)
112{
113	return __crc32c_vpmsum_finup(shash_desc_ctx(desc), data, len, out);
114}
115
116static int crc32c_vpmsum_final(struct shash_desc *desc, u8 *out)
117{
118	u32 *crcp = shash_desc_ctx(desc);
119
120	*(__le32 *)out = ~cpu_to_le32p(crcp);
121
122	return 0;
123}
124
125static int crc32c_vpmsum_digest(struct shash_desc *desc, const u8 *data,
126			       unsigned int len, u8 *out)
127{
128	return __crc32c_vpmsum_finup(crypto_shash_ctx(desc->tfm), data, len,
129				     out);
130}
131
132static struct shash_alg alg = {
133	.setkey		= crc32c_vpmsum_setkey,
134	.init		= crc32c_vpmsum_init,
135	.update		= crc32c_vpmsum_update,
136	.final		= crc32c_vpmsum_final,
137	.finup		= crc32c_vpmsum_finup,
138	.digest		= crc32c_vpmsum_digest,
139	.descsize	= sizeof(u32),
140	.digestsize	= CHKSUM_DIGEST_SIZE,
141	.base		= {
142		.cra_name		= "crc32c",
143		.cra_driver_name	= "crc32c-vpmsum",
144		.cra_priority		= 200,
145		.cra_flags		= CRYPTO_ALG_OPTIONAL_KEY,
146		.cra_blocksize		= CHKSUM_BLOCK_SIZE,
147		.cra_ctxsize		= sizeof(u32),
148		.cra_module		= THIS_MODULE,
149		.cra_init		= crc32c_vpmsum_cra_init,
150	}
151};
152
153static int __init crc32c_vpmsum_mod_init(void)
154{
155	if (!cpu_has_feature(CPU_FTR_ARCH_207S))
156		return -ENODEV;
157
158	return crypto_register_shash(&alg);
159}
160
161static void __exit crc32c_vpmsum_mod_fini(void)
162{
163	crypto_unregister_shash(&alg);
164}
165
166module_cpu_feature_match(PPC_MODULE_FEATURE_VEC_CRYPTO, crc32c_vpmsum_mod_init);
167module_exit(crc32c_vpmsum_mod_fini);
168
169MODULE_AUTHOR("Anton Blanchard <anton@samba.org>");
170MODULE_DESCRIPTION("CRC32C using vector polynomial multiply-sum instructions");
171MODULE_LICENSE("GPL");
172MODULE_ALIAS_CRYPTO("crc32c");
173MODULE_ALIAS_CRYPTO("crc32c-vpmsum");