1 // SPDX-License-Identifier: GPL-2.0 <<
2 /* 1 /*
3 * RAID-6 data recovery in dual failure mode b 2 * RAID-6 data recovery in dual failure mode based on the XC instruction.
4 * 3 *
5 * Copyright IBM Corp. 2016 4 * Copyright IBM Corp. 2016
6 * Author(s): Martin Schwidefsky <schwidefsky@ 5 * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
7 */ 6 */
8 7
9 #include <linux/export.h> 8 #include <linux/export.h>
10 #include <linux/raid/pq.h> 9 #include <linux/raid/pq.h>
11 10
12 static inline void xor_block(u8 *p1, u8 *p2) 11 static inline void xor_block(u8 *p1, u8 *p2)
13 { 12 {
14 typedef struct { u8 _[256]; } addrtype 13 typedef struct { u8 _[256]; } addrtype;
15 14
16 asm volatile( 15 asm volatile(
17 " xc 0(256,%[p1]),0 16 " xc 0(256,%[p1]),0(%[p2])\n"
18 : "+m" (*(addrtype *) p1) : "m 17 : "+m" (*(addrtype *) p1) : "m" (*(addrtype *) p2),
19 [p1] "a" (p1), [p2] "a" (p2) 18 [p1] "a" (p1), [p2] "a" (p2) : "cc");
20 } 19 }
21 20
22 /* Recover two failed data blocks. */ 21 /* Recover two failed data blocks. */
23 static void raid6_2data_recov_s390xc(int disks 22 static void raid6_2data_recov_s390xc(int disks, size_t bytes, int faila,
24 int failb, void **ptrs) 23 int failb, void **ptrs)
25 { 24 {
26 u8 *p, *q, *dp, *dq; 25 u8 *p, *q, *dp, *dq;
27 const u8 *pbmul; /* P multiplie 26 const u8 *pbmul; /* P multiplier table for B data */
28 const u8 *qmul; /* Q multiplie 27 const u8 *qmul; /* Q multiplier table (for both) */
29 int i; 28 int i;
30 29
31 p = (u8 *)ptrs[disks-2]; 30 p = (u8 *)ptrs[disks-2];
32 q = (u8 *)ptrs[disks-1]; 31 q = (u8 *)ptrs[disks-1];
33 32
34 /* Compute syndrome with zero for the 33 /* Compute syndrome with zero for the missing data pages
35 Use the dead data pages as temporar 34 Use the dead data pages as temporary storage for
36 delta p and delta q */ 35 delta p and delta q */
37 dp = (u8 *)ptrs[faila]; 36 dp = (u8 *)ptrs[faila];
38 ptrs[faila] = (void *)raid6_empty_zero 37 ptrs[faila] = (void *)raid6_empty_zero_page;
39 ptrs[disks-2] = dp; 38 ptrs[disks-2] = dp;
40 dq = (u8 *)ptrs[failb]; 39 dq = (u8 *)ptrs[failb];
41 ptrs[failb] = (void *)raid6_empty_zero 40 ptrs[failb] = (void *)raid6_empty_zero_page;
42 ptrs[disks-1] = dq; 41 ptrs[disks-1] = dq;
43 42
44 raid6_call.gen_syndrome(disks, bytes, 43 raid6_call.gen_syndrome(disks, bytes, ptrs);
45 44
46 /* Restore pointer table */ 45 /* Restore pointer table */
47 ptrs[faila] = dp; 46 ptrs[faila] = dp;
48 ptrs[failb] = dq; 47 ptrs[failb] = dq;
49 ptrs[disks-2] = p; 48 ptrs[disks-2] = p;
50 ptrs[disks-1] = q; 49 ptrs[disks-1] = q;
51 50
52 /* Now, pick the proper data tables */ 51 /* Now, pick the proper data tables */
53 pbmul = raid6_gfmul[raid6_gfexi[failb- 52 pbmul = raid6_gfmul[raid6_gfexi[failb-faila]];
54 qmul = raid6_gfmul[raid6_gfinv[raid6_ 53 qmul = raid6_gfmul[raid6_gfinv[raid6_gfexp[faila]^raid6_gfexp[failb]]];
55 54
56 /* Now do it... */ 55 /* Now do it... */
57 while (bytes) { 56 while (bytes) {
58 xor_block(dp, p); 57 xor_block(dp, p);
59 xor_block(dq, q); 58 xor_block(dq, q);
60 for (i = 0; i < 256; i++) 59 for (i = 0; i < 256; i++)
61 dq[i] = pbmul[dp[i]] ^ 60 dq[i] = pbmul[dp[i]] ^ qmul[dq[i]];
62 xor_block(dp, dq); 61 xor_block(dp, dq);
63 p += 256; 62 p += 256;
64 q += 256; 63 q += 256;
65 dp += 256; 64 dp += 256;
66 dq += 256; 65 dq += 256;
67 bytes -= 256; 66 bytes -= 256;
68 } 67 }
69 } 68 }
70 69
71 /* Recover failure of one data block plus the 70 /* Recover failure of one data block plus the P block */
72 static void raid6_datap_recov_s390xc(int disks 71 static void raid6_datap_recov_s390xc(int disks, size_t bytes, int faila,
73 void **ptrs) 72 void **ptrs)
74 { 73 {
75 u8 *p, *q, *dq; 74 u8 *p, *q, *dq;
76 const u8 *qmul; /* Q multiplie 75 const u8 *qmul; /* Q multiplier table */
77 int i; 76 int i;
78 77
79 p = (u8 *)ptrs[disks-2]; 78 p = (u8 *)ptrs[disks-2];
80 q = (u8 *)ptrs[disks-1]; 79 q = (u8 *)ptrs[disks-1];
81 80
82 /* Compute syndrome with zero for the 81 /* Compute syndrome with zero for the missing data page
83 Use the dead data page as temporary 82 Use the dead data page as temporary storage for delta q */
84 dq = (u8 *)ptrs[faila]; 83 dq = (u8 *)ptrs[faila];
85 ptrs[faila] = (void *)raid6_empty_zero 84 ptrs[faila] = (void *)raid6_empty_zero_page;
86 ptrs[disks-1] = dq; 85 ptrs[disks-1] = dq;
87 86
88 raid6_call.gen_syndrome(disks, bytes, 87 raid6_call.gen_syndrome(disks, bytes, ptrs);
89 88
90 /* Restore pointer table */ 89 /* Restore pointer table */
91 ptrs[faila] = dq; 90 ptrs[faila] = dq;
92 ptrs[disks-1] = q; 91 ptrs[disks-1] = q;
93 92
94 /* Now, pick the proper data tables */ 93 /* Now, pick the proper data tables */
95 qmul = raid6_gfmul[raid6_gfinv[raid6_ 94 qmul = raid6_gfmul[raid6_gfinv[raid6_gfexp[faila]]];
96 95
97 /* Now do it... */ 96 /* Now do it... */
98 while (bytes) { 97 while (bytes) {
99 xor_block(dq, q); 98 xor_block(dq, q);
100 for (i = 0; i < 256; i++) 99 for (i = 0; i < 256; i++)
101 dq[i] = qmul[dq[i]]; 100 dq[i] = qmul[dq[i]];
102 xor_block(p, dq); 101 xor_block(p, dq);
103 p += 256; 102 p += 256;
104 q += 256; 103 q += 256;
105 dq += 256; 104 dq += 256;
106 bytes -= 256; 105 bytes -= 256;
107 } 106 }
108 } 107 }
109 108
110 109
111 const struct raid6_recov_calls raid6_recov_s39 110 const struct raid6_recov_calls raid6_recov_s390xc = {
112 .data2 = raid6_2data_recov_s390xc, 111 .data2 = raid6_2data_recov_s390xc,
113 .datap = raid6_datap_recov_s390xc, 112 .datap = raid6_datap_recov_s390xc,
114 .valid = NULL, 113 .valid = NULL,
115 .name = "s390xc", 114 .name = "s390xc",
116 .priority = 1, 115 .priority = 1,
117 }; 116 };
118 117
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