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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * xor.c : Multiple Devices driver for Linux
4 *
5 * Copyright (C) 1996, 1997, 1998, 1999, 2000,
6 * Ingo Molnar, Matti Aarnio, Jakub Jelinek, Richard Henderson.
7 *
8 * Dispatch optimized RAID-5 checksumming functions.
9 */
10
11#define BH_TRACE 0
12#include <linux/module.h>
13#include <linux/gfp.h>
14#include <linux/raid/xor.h>
15#include <linux/jiffies.h>
16#include <linux/preempt.h>
17#include <asm/xor.h>
18
19#ifndef XOR_SELECT_TEMPLATE
20#define XOR_SELECT_TEMPLATE(x) (x)
21#endif
22
23/* The xor routines to use. */
24static struct xor_block_template *active_template;
25
26void
27xor_blocks(unsigned int src_count, unsigned int bytes, void *dest, void **srcs)
28{
29 unsigned long *p1, *p2, *p3, *p4;
30
31 p1 = (unsigned long *) srcs[0];
32 if (src_count == 1) {
33 active_template->do_2(bytes, dest, p1);
34 return;
35 }
36
37 p2 = (unsigned long *) srcs[1];
38 if (src_count == 2) {
39 active_template->do_3(bytes, dest, p1, p2);
40 return;
41 }
42
43 p3 = (unsigned long *) srcs[2];
44 if (src_count == 3) {
45 active_template->do_4(bytes, dest, p1, p2, p3);
46 return;
47 }
48
49 p4 = (unsigned long *) srcs[3];
50 active_template->do_5(bytes, dest, p1, p2, p3, p4);
51}
52EXPORT_SYMBOL(xor_blocks);
53
54/* Set of all registered templates. */
55static struct xor_block_template *__initdata template_list;
56
57#ifndef MODULE
58static void __init do_xor_register(struct xor_block_template *tmpl)
59{
60 tmpl->next = template_list;
61 template_list = tmpl;
62}
63
64static int __init register_xor_blocks(void)
65{
66 active_template = XOR_SELECT_TEMPLATE(NULL);
67
68 if (!active_template) {
69#define xor_speed do_xor_register
70 // register all the templates and pick the first as the default
71 XOR_TRY_TEMPLATES;
72#undef xor_speed
73 active_template = template_list;
74 }
75 return 0;
76}
77#endif
78
79#define BENCH_SIZE 4096
80#define REPS 800U
81
82static void __init
83do_xor_speed(struct xor_block_template *tmpl, void *b1, void *b2)
84{
85 int speed;
86 int i, j;
87 ktime_t min, start, diff;
88
89 tmpl->next = template_list;
90 template_list = tmpl;
91
92 preempt_disable();
93
94 min = (ktime_t)S64_MAX;
95 for (i = 0; i < 3; i++) {
96 start = ktime_get();
97 for (j = 0; j < REPS; j++) {
98 mb(); /* prevent loop optimization */
99 tmpl->do_2(BENCH_SIZE, b1, b2);
100 mb();
101 }
102 diff = ktime_sub(ktime_get(), start);
103 if (diff < min)
104 min = diff;
105 }
106
107 preempt_enable();
108
109 // bytes/ns == GB/s, multiply by 1000 to get MB/s [not MiB/s]
110 if (!min)
111 min = 1;
112 speed = (1000 * REPS * BENCH_SIZE) / (unsigned int)ktime_to_ns(min);
113 tmpl->speed = speed;
114
115 pr_info(" %-16s: %5d MB/sec\n", tmpl->name, speed);
116}
117
118static int __init
119calibrate_xor_blocks(void)
120{
121 void *b1, *b2;
122 struct xor_block_template *f, *fastest;
123
124 fastest = XOR_SELECT_TEMPLATE(NULL);
125
126 if (fastest) {
127 printk(KERN_INFO "xor: automatically using best "
128 "checksumming function %-10s\n",
129 fastest->name);
130 goto out;
131 }
132
133 b1 = (void *) __get_free_pages(GFP_KERNEL, 2);
134 if (!b1) {
135 printk(KERN_WARNING "xor: Yikes! No memory available.\n");
136 return -ENOMEM;
137 }
138 b2 = b1 + 2*PAGE_SIZE + BENCH_SIZE;
139
140 /*
141 * If this arch/cpu has a short-circuited selection, don't loop through
142 * all the possible functions, just test the best one
143 */
144
145#define xor_speed(templ) do_xor_speed((templ), b1, b2)
146
147 printk(KERN_INFO "xor: measuring software checksum speed\n");
148 template_list = NULL;
149 XOR_TRY_TEMPLATES;
150 fastest = template_list;
151 for (f = fastest; f; f = f->next)
152 if (f->speed > fastest->speed)
153 fastest = f;
154
155 pr_info("xor: using function: %s (%d MB/sec)\n",
156 fastest->name, fastest->speed);
157
158#undef xor_speed
159
160 free_pages((unsigned long)b1, 2);
161out:
162 active_template = fastest;
163 return 0;
164}
165
166static __exit void xor_exit(void) { }
167
168MODULE_LICENSE("GPL");
169
170#ifndef MODULE
171/* when built-in xor.o must initialize before drivers/md/md.o */
172core_initcall(register_xor_blocks);
173#endif
174
175module_init(calibrate_xor_blocks);
176module_exit(xor_exit);
1/*
2 * xor.c : Multiple Devices driver for Linux
3 *
4 * Copyright (C) 1996, 1997, 1998, 1999, 2000,
5 * Ingo Molnar, Matti Aarnio, Jakub Jelinek, Richard Henderson.
6 *
7 * Dispatch optimized RAID-5 checksumming functions.
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation; either version 2, or (at your option)
12 * any later version.
13 *
14 * You should have received a copy of the GNU General Public License
15 * (for example /usr/src/linux/COPYING); if not, write to the Free
16 * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
17 */
18
19#define BH_TRACE 0
20#include <linux/module.h>
21#include <linux/gfp.h>
22#include <linux/raid/xor.h>
23#include <linux/jiffies.h>
24#include <linux/preempt.h>
25#include <asm/xor.h>
26
27#ifndef XOR_SELECT_TEMPLATE
28#define XOR_SELECT_TEMPLATE(x) (x)
29#endif
30
31/* The xor routines to use. */
32static struct xor_block_template *active_template;
33
34void
35xor_blocks(unsigned int src_count, unsigned int bytes, void *dest, void **srcs)
36{
37 unsigned long *p1, *p2, *p3, *p4;
38
39 p1 = (unsigned long *) srcs[0];
40 if (src_count == 1) {
41 active_template->do_2(bytes, dest, p1);
42 return;
43 }
44
45 p2 = (unsigned long *) srcs[1];
46 if (src_count == 2) {
47 active_template->do_3(bytes, dest, p1, p2);
48 return;
49 }
50
51 p3 = (unsigned long *) srcs[2];
52 if (src_count == 3) {
53 active_template->do_4(bytes, dest, p1, p2, p3);
54 return;
55 }
56
57 p4 = (unsigned long *) srcs[3];
58 active_template->do_5(bytes, dest, p1, p2, p3, p4);
59}
60EXPORT_SYMBOL(xor_blocks);
61
62/* Set of all registered templates. */
63static struct xor_block_template *__initdata template_list;
64
65#define BENCH_SIZE (PAGE_SIZE)
66
67static void __init
68do_xor_speed(struct xor_block_template *tmpl, void *b1, void *b2)
69{
70 int speed;
71 unsigned long now, j;
72 int i, count, max;
73
74 tmpl->next = template_list;
75 template_list = tmpl;
76
77 preempt_disable();
78
79 /*
80 * Count the number of XORs done during a whole jiffy, and use
81 * this to calculate the speed of checksumming. We use a 2-page
82 * allocation to have guaranteed color L1-cache layout.
83 */
84 max = 0;
85 for (i = 0; i < 5; i++) {
86 j = jiffies;
87 count = 0;
88 while ((now = jiffies) == j)
89 cpu_relax();
90 while (time_before(jiffies, now + 1)) {
91 mb(); /* prevent loop optimzation */
92 tmpl->do_2(BENCH_SIZE, b1, b2);
93 mb();
94 count++;
95 mb();
96 }
97 if (count > max)
98 max = count;
99 }
100
101 preempt_enable();
102
103 speed = max * (HZ * BENCH_SIZE / 1024);
104 tmpl->speed = speed;
105
106 printk(KERN_INFO " %-10s: %5d.%03d MB/sec\n", tmpl->name,
107 speed / 1000, speed % 1000);
108}
109
110static int __init
111calibrate_xor_blocks(void)
112{
113 void *b1, *b2;
114 struct xor_block_template *f, *fastest;
115
116 fastest = XOR_SELECT_TEMPLATE(NULL);
117
118 if (fastest) {
119 printk(KERN_INFO "xor: automatically using best "
120 "checksumming function %-10s\n",
121 fastest->name);
122 goto out;
123 }
124
125 b1 = (void *) __get_free_pages(GFP_KERNEL, 2);
126 if (!b1) {
127 printk(KERN_WARNING "xor: Yikes! No memory available.\n");
128 return -ENOMEM;
129 }
130 b2 = b1 + 2*PAGE_SIZE + BENCH_SIZE;
131
132 /*
133 * If this arch/cpu has a short-circuited selection, don't loop through
134 * all the possible functions, just test the best one
135 */
136
137#define xor_speed(templ) do_xor_speed((templ), b1, b2)
138
139 printk(KERN_INFO "xor: measuring software checksum speed\n");
140 XOR_TRY_TEMPLATES;
141 fastest = template_list;
142 for (f = fastest; f; f = f->next)
143 if (f->speed > fastest->speed)
144 fastest = f;
145
146 printk(KERN_INFO "xor: using function: %s (%d.%03d MB/sec)\n",
147 fastest->name, fastest->speed / 1000, fastest->speed % 1000);
148
149#undef xor_speed
150
151 free_pages((unsigned long)b1, 2);
152out:
153 active_template = fastest;
154 return 0;
155}
156
157static __exit void xor_exit(void) { }
158
159MODULE_LICENSE("GPL");
160
161/* when built-in xor.o must initialize before drivers/md/md.o */
162core_initcall(calibrate_xor_blocks);
163module_exit(xor_exit);