1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Calculate a CRC T10-DIF with vpmsum acceleration
4 *
5 * Copyright 2017, Daniel Axtens, IBM Corporation.
6 * [based on crc32c-vpmsum_glue.c]
7 */
8
9#include <linux/crc-t10dif.h>
10#include <crypto/internal/hash.h>
11#include <crypto/internal/simd.h>
12#include <linux/init.h>
13#include <linux/module.h>
14#include <linux/string.h>
15#include <linux/kernel.h>
16#include <linux/cpufeature.h>
17#include <asm/simd.h>
18#include <asm/switch_to.h>
19
20#define VMX_ALIGN 16
21#define VMX_ALIGN_MASK (VMX_ALIGN-1)
22
23#define VECTOR_BREAKPOINT 64
24
25u32 __crct10dif_vpmsum(u32 crc, unsigned char const *p, size_t len);
26
27static u16 crct10dif_vpmsum(u16 crci, unsigned char const *p, size_t len)
28{
29 unsigned int prealign;
30 unsigned int tail;
31 u32 crc = crci;
32
33 if (len < (VECTOR_BREAKPOINT + VMX_ALIGN) || !crypto_simd_usable())
34 return crc_t10dif_generic(crc, buffer: p, len);
35
36 if ((unsigned long)p & VMX_ALIGN_MASK) {
37 prealign = VMX_ALIGN - ((unsigned long)p & VMX_ALIGN_MASK);
38 crc = crc_t10dif_generic(crc, buffer: p, len: prealign);
39 len -= prealign;
40 p += prealign;
41 }
42
43 if (len & ~VMX_ALIGN_MASK) {
44 crc <<= 16;
45 preempt_disable();
46 pagefault_disable();
47 enable_kernel_altivec();
48 crc = __crct10dif_vpmsum(crc, p, len: len & ~VMX_ALIGN_MASK);
49 disable_kernel_altivec();
50 pagefault_enable();
51 preempt_enable();
52 crc >>= 16;
53 }
54
55 tail = len & VMX_ALIGN_MASK;
56 if (tail) {
57 p += len & ~VMX_ALIGN_MASK;
58 crc = crc_t10dif_generic(crc, buffer: p, len: tail);
59 }
60
61 return crc & 0xffff;
62}
63
64static int crct10dif_vpmsum_init(struct shash_desc *desc)
65{
66 u16 *crc = shash_desc_ctx(desc);
67
68 *crc = 0;
69 return 0;
70}
71
72static int crct10dif_vpmsum_update(struct shash_desc *desc, const u8 *data,
73 unsigned int length)
74{
75 u16 *crc = shash_desc_ctx(desc);
76
77 *crc = crct10dif_vpmsum(crci: *crc, p: data, len: length);
78
79 return 0;
80}
81
82
83static int crct10dif_vpmsum_final(struct shash_desc *desc, u8 *out)
84{
85 u16 *crcp = shash_desc_ctx(desc);
86
87 *(u16 *)out = *crcp;
88 return 0;
89}
90
91static struct shash_alg alg = {
92 .init = crct10dif_vpmsum_init,
93 .update = crct10dif_vpmsum_update,
94 .final = crct10dif_vpmsum_final,
95 .descsize = CRC_T10DIF_DIGEST_SIZE,
96 .digestsize = CRC_T10DIF_DIGEST_SIZE,
97 .base = {
98 .cra_name = "crct10dif",
99 .cra_driver_name = "crct10dif-vpmsum",
100 .cra_priority = 200,
101 .cra_blocksize = CRC_T10DIF_BLOCK_SIZE,
102 .cra_module = THIS_MODULE,
103 }
104};
105
106static int __init crct10dif_vpmsum_mod_init(void)
107{
108 if (!cpu_has_feature(CPU_FTR_ARCH_207S))
109 return -ENODEV;
110
111 return crypto_register_shash(alg: &alg);
112}
113
114static void __exit crct10dif_vpmsum_mod_fini(void)
115{
116 crypto_unregister_shash(alg: &alg);
117}
118
119module_cpu_feature_match(PPC_MODULE_FEATURE_VEC_CRYPTO, crct10dif_vpmsum_mod_init);
120module_exit(crct10dif_vpmsum_mod_fini);
121
122MODULE_AUTHOR("Daniel Axtens <dja@axtens.net>");
123MODULE_DESCRIPTION("CRCT10DIF using vector polynomial multiply-sum instructions");
124MODULE_LICENSE("GPL");
125MODULE_ALIAS_CRYPTO("crct10dif");
126MODULE_ALIAS_CRYPTO("crct10dif-vpmsum");
127

source code of linux/arch/powerpc/crypto/crct10dif-vpmsum_glue.c