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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * RAID-6 data recovery in dual failure mode based on the XC instruction.
4 *
5 * Copyright IBM Corp. 2016
6 * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
7 */
8
9#include <linux/export.h>
10#include <linux/raid/pq.h>
11
12static inline void xor_block(u8 *p1, u8 *p2)
13{
14 typedef struct { u8 _[256]; } addrtype;
15
16 asm volatile(
17 " xc 0(256,%[p1]),0(%[p2])\n"
18 : "+m" (*(addrtype *) p1) : "m" (*(addrtype *) p2),
19 [p1] "a" (p1), [p2] "a" (p2) : "cc");
20}
21
22/* Recover two failed data blocks. */
23static void raid6_2data_recov_s390xc(int disks, size_t bytes, int faila,
24 int failb, void **ptrs)
25{
26 u8 *p, *q, *dp, *dq;
27 const u8 *pbmul; /* P multiplier table for B data */
28 const u8 *qmul; /* Q multiplier table (for both) */
29 int i;
30
31 p = (u8 *)ptrs[disks-2];
32 q = (u8 *)ptrs[disks-1];
33
34 /* Compute syndrome with zero for the missing data pages
35 Use the dead data pages as temporary storage for
36 delta p and delta q */
37 dp = (u8 *)ptrs[faila];
38 ptrs[faila] = (void *)raid6_empty_zero_page;
39 ptrs[disks-2] = dp;
40 dq = (u8 *)ptrs[failb];
41 ptrs[failb] = (void *)raid6_empty_zero_page;
42 ptrs[disks-1] = dq;
43
44 raid6_call.gen_syndrome(disks, bytes, ptrs);
45
46 /* Restore pointer table */
47 ptrs[faila] = dp;
48 ptrs[failb] = dq;
49 ptrs[disks-2] = p;
50 ptrs[disks-1] = q;
51
52 /* Now, pick the proper data tables */
53 pbmul = raid6_gfmul[raid6_gfexi[failb-faila]];
54 qmul = raid6_gfmul[raid6_gfinv[raid6_gfexp[faila]^raid6_gfexp[failb]]];
55
56 /* Now do it... */
57 while (bytes) {
58 xor_block(dp, p);
59 xor_block(dq, q);
60 for (i = 0; i < 256; i++)
61 dq[i] = pbmul[dp[i]] ^ qmul[dq[i]];
62 xor_block(dp, dq);
63 p += 256;
64 q += 256;
65 dp += 256;
66 dq += 256;
67 bytes -= 256;
68 }
69}
70
71/* Recover failure of one data block plus the P block */
72static void raid6_datap_recov_s390xc(int disks, size_t bytes, int faila,
73 void **ptrs)
74{
75 u8 *p, *q, *dq;
76 const u8 *qmul; /* Q multiplier table */
77 int i;
78
79 p = (u8 *)ptrs[disks-2];
80 q = (u8 *)ptrs[disks-1];
81
82 /* Compute syndrome with zero for the missing data page
83 Use the dead data page as temporary storage for delta q */
84 dq = (u8 *)ptrs[faila];
85 ptrs[faila] = (void *)raid6_empty_zero_page;
86 ptrs[disks-1] = dq;
87
88 raid6_call.gen_syndrome(disks, bytes, ptrs);
89
90 /* Restore pointer table */
91 ptrs[faila] = dq;
92 ptrs[disks-1] = q;
93
94 /* Now, pick the proper data tables */
95 qmul = raid6_gfmul[raid6_gfinv[raid6_gfexp[faila]]];
96
97 /* Now do it... */
98 while (bytes) {
99 xor_block(dq, q);
100 for (i = 0; i < 256; i++)
101 dq[i] = qmul[dq[i]];
102 xor_block(p, dq);
103 p += 256;
104 q += 256;
105 dq += 256;
106 bytes -= 256;
107 }
108}
109
110
111const struct raid6_recov_calls raid6_recov_s390xc = {
112 .data2 = raid6_2data_recov_s390xc,
113 .datap = raid6_datap_recov_s390xc,
114 .valid = NULL,
115 .name = "s390xc",
116 .priority = 1,
117};
1/*
2 * RAID-6 data recovery in dual failure mode based on the XC instruction.
3 *
4 * Copyright IBM Corp. 2016
5 * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
6 */
7
8#include <linux/export.h>
9#include <linux/raid/pq.h>
10
11static inline void xor_block(u8 *p1, u8 *p2)
12{
13 typedef struct { u8 _[256]; } addrtype;
14
15 asm volatile(
16 " xc 0(256,%[p1]),0(%[p2])\n"
17 : "+m" (*(addrtype *) p1) : "m" (*(addrtype *) p2),
18 [p1] "a" (p1), [p2] "a" (p2) : "cc");
19}
20
21/* Recover two failed data blocks. */
22static void raid6_2data_recov_s390xc(int disks, size_t bytes, int faila,
23 int failb, void **ptrs)
24{
25 u8 *p, *q, *dp, *dq;
26 const u8 *pbmul; /* P multiplier table for B data */
27 const u8 *qmul; /* Q multiplier table (for both) */
28 int i;
29
30 p = (u8 *)ptrs[disks-2];
31 q = (u8 *)ptrs[disks-1];
32
33 /* Compute syndrome with zero for the missing data pages
34 Use the dead data pages as temporary storage for
35 delta p and delta q */
36 dp = (u8 *)ptrs[faila];
37 ptrs[faila] = (void *)raid6_empty_zero_page;
38 ptrs[disks-2] = dp;
39 dq = (u8 *)ptrs[failb];
40 ptrs[failb] = (void *)raid6_empty_zero_page;
41 ptrs[disks-1] = dq;
42
43 raid6_call.gen_syndrome(disks, bytes, ptrs);
44
45 /* Restore pointer table */
46 ptrs[faila] = dp;
47 ptrs[failb] = dq;
48 ptrs[disks-2] = p;
49 ptrs[disks-1] = q;
50
51 /* Now, pick the proper data tables */
52 pbmul = raid6_gfmul[raid6_gfexi[failb-faila]];
53 qmul = raid6_gfmul[raid6_gfinv[raid6_gfexp[faila]^raid6_gfexp[failb]]];
54
55 /* Now do it... */
56 while (bytes) {
57 xor_block(dp, p);
58 xor_block(dq, q);
59 for (i = 0; i < 256; i++)
60 dq[i] = pbmul[dp[i]] ^ qmul[dq[i]];
61 xor_block(dp, dq);
62 p += 256;
63 q += 256;
64 dp += 256;
65 dq += 256;
66 bytes -= 256;
67 }
68}
69
70/* Recover failure of one data block plus the P block */
71static void raid6_datap_recov_s390xc(int disks, size_t bytes, int faila,
72 void **ptrs)
73{
74 u8 *p, *q, *dq;
75 const u8 *qmul; /* Q multiplier table */
76 int i;
77
78 p = (u8 *)ptrs[disks-2];
79 q = (u8 *)ptrs[disks-1];
80
81 /* Compute syndrome with zero for the missing data page
82 Use the dead data page as temporary storage for delta q */
83 dq = (u8 *)ptrs[faila];
84 ptrs[faila] = (void *)raid6_empty_zero_page;
85 ptrs[disks-1] = dq;
86
87 raid6_call.gen_syndrome(disks, bytes, ptrs);
88
89 /* Restore pointer table */
90 ptrs[faila] = dq;
91 ptrs[disks-1] = q;
92
93 /* Now, pick the proper data tables */
94 qmul = raid6_gfmul[raid6_gfinv[raid6_gfexp[faila]]];
95
96 /* Now do it... */
97 while (bytes) {
98 xor_block(dq, q);
99 for (i = 0; i < 256; i++)
100 dq[i] = qmul[dq[i]];
101 xor_block(p, dq);
102 p += 256;
103 q += 256;
104 dq += 256;
105 bytes -= 256;
106 }
107}
108
109
110const struct raid6_recov_calls raid6_recov_s390xc = {
111 .data2 = raid6_2data_recov_s390xc,
112 .datap = raid6_datap_recov_s390xc,
113 .valid = NULL,
114 .name = "s390xc",
115 .priority = 1,
116};