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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#define BENCH_SIZE (PAGE_SIZE)
58
59static void __init
60do_xor_speed(struct xor_block_template *tmpl, void *b1, void *b2)
61{
62 int speed;
63 unsigned long now, j;
64 int i, count, max;
65
66 tmpl->next = template_list;
67 template_list = tmpl;
68
69 preempt_disable();
70
71 /*
72 * Count the number of XORs done during a whole jiffy, and use
73 * this to calculate the speed of checksumming. We use a 2-page
74 * allocation to have guaranteed color L1-cache layout.
75 */
76 max = 0;
77 for (i = 0; i < 5; i++) {
78 j = jiffies;
79 count = 0;
80 while ((now = jiffies) == j)
81 cpu_relax();
82 while (time_before(jiffies, now + 1)) {
83 mb(); /* prevent loop optimzation */
84 tmpl->do_2(BENCH_SIZE, b1, b2);
85 mb();
86 count++;
87 mb();
88 }
89 if (count > max)
90 max = count;
91 }
92
93 preempt_enable();
94
95 speed = max * (HZ * BENCH_SIZE / 1024);
96 tmpl->speed = speed;
97
98 printk(KERN_INFO " %-10s: %5d.%03d MB/sec\n", tmpl->name,
99 speed / 1000, speed % 1000);
100}
101
102static int __init
103calibrate_xor_blocks(void)
104{
105 void *b1, *b2;
106 struct xor_block_template *f, *fastest;
107
108 fastest = XOR_SELECT_TEMPLATE(NULL);
109
110 if (fastest) {
111 printk(KERN_INFO "xor: automatically using best "
112 "checksumming function %-10s\n",
113 fastest->name);
114 goto out;
115 }
116
117 b1 = (void *) __get_free_pages(GFP_KERNEL, 2);
118 if (!b1) {
119 printk(KERN_WARNING "xor: Yikes! No memory available.\n");
120 return -ENOMEM;
121 }
122 b2 = b1 + 2*PAGE_SIZE + BENCH_SIZE;
123
124 /*
125 * If this arch/cpu has a short-circuited selection, don't loop through
126 * all the possible functions, just test the best one
127 */
128
129#define xor_speed(templ) do_xor_speed((templ), b1, b2)
130
131 printk(KERN_INFO "xor: measuring software checksum speed\n");
132 XOR_TRY_TEMPLATES;
133 fastest = template_list;
134 for (f = fastest; f; f = f->next)
135 if (f->speed > fastest->speed)
136 fastest = f;
137
138 printk(KERN_INFO "xor: using function: %s (%d.%03d MB/sec)\n",
139 fastest->name, fastest->speed / 1000, fastest->speed % 1000);
140
141#undef xor_speed
142
143 free_pages((unsigned long)b1, 2);
144out:
145 active_template = fastest;
146 return 0;
147}
148
149static __exit void xor_exit(void) { }
150
151MODULE_LICENSE("GPL");
152
153/* when built-in xor.o must initialize before drivers/md/md.o */
154core_initcall(calibrate_xor_blocks);
155module_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 <asm/xor.h>
25
26/* The xor routines to use. */
27static struct xor_block_template *active_template;
28
29void
30xor_blocks(unsigned int src_count, unsigned int bytes, void *dest, void **srcs)
31{
32 unsigned long *p1, *p2, *p3, *p4;
33
34 p1 = (unsigned long *) srcs[0];
35 if (src_count == 1) {
36 active_template->do_2(bytes, dest, p1);
37 return;
38 }
39
40 p2 = (unsigned long *) srcs[1];
41 if (src_count == 2) {
42 active_template->do_3(bytes, dest, p1, p2);
43 return;
44 }
45
46 p3 = (unsigned long *) srcs[2];
47 if (src_count == 3) {
48 active_template->do_4(bytes, dest, p1, p2, p3);
49 return;
50 }
51
52 p4 = (unsigned long *) srcs[3];
53 active_template->do_5(bytes, dest, p1, p2, p3, p4);
54}
55EXPORT_SYMBOL(xor_blocks);
56
57/* Set of all registered templates. */
58static struct xor_block_template *template_list;
59
60#define BENCH_SIZE (PAGE_SIZE)
61
62static void
63do_xor_speed(struct xor_block_template *tmpl, void *b1, void *b2)
64{
65 int speed;
66 unsigned long now;
67 int i, count, max;
68
69 tmpl->next = template_list;
70 template_list = tmpl;
71
72 /*
73 * Count the number of XORs done during a whole jiffy, and use
74 * this to calculate the speed of checksumming. We use a 2-page
75 * allocation to have guaranteed color L1-cache layout.
76 */
77 max = 0;
78 for (i = 0; i < 5; i++) {
79 now = jiffies;
80 count = 0;
81 while (jiffies == now) {
82 mb(); /* prevent loop optimzation */
83 tmpl->do_2(BENCH_SIZE, b1, b2);
84 mb();
85 count++;
86 mb();
87 }
88 if (count > max)
89 max = count;
90 }
91
92 speed = max * (HZ * BENCH_SIZE / 1024);
93 tmpl->speed = speed;
94
95 printk(KERN_INFO " %-10s: %5d.%03d MB/sec\n", tmpl->name,
96 speed / 1000, speed % 1000);
97}
98
99static int __init
100calibrate_xor_blocks(void)
101{
102 void *b1, *b2;
103 struct xor_block_template *f, *fastest;
104
105 /*
106 * Note: Since the memory is not actually used for _anything_ but to
107 * test the XOR speed, we don't really want kmemcheck to warn about
108 * reading uninitialized bytes here.
109 */
110 b1 = (void *) __get_free_pages(GFP_KERNEL | __GFP_NOTRACK, 2);
111 if (!b1) {
112 printk(KERN_WARNING "xor: Yikes! No memory available.\n");
113 return -ENOMEM;
114 }
115 b2 = b1 + 2*PAGE_SIZE + BENCH_SIZE;
116
117 /*
118 * If this arch/cpu has a short-circuited selection, don't loop through
119 * all the possible functions, just test the best one
120 */
121
122 fastest = NULL;
123
124#ifdef XOR_SELECT_TEMPLATE
125 fastest = XOR_SELECT_TEMPLATE(fastest);
126#endif
127
128#define xor_speed(templ) do_xor_speed((templ), b1, b2)
129
130 if (fastest) {
131 printk(KERN_INFO "xor: automatically using best "
132 "checksumming function: %s\n",
133 fastest->name);
134 xor_speed(fastest);
135 } else {
136 printk(KERN_INFO "xor: measuring software checksum speed\n");
137 XOR_TRY_TEMPLATES;
138 fastest = template_list;
139 for (f = fastest; f; f = f->next)
140 if (f->speed > fastest->speed)
141 fastest = f;
142 }
143
144 printk(KERN_INFO "xor: using function: %s (%d.%03d MB/sec)\n",
145 fastest->name, fastest->speed / 1000, fastest->speed % 1000);
146
147#undef xor_speed
148
149 free_pages((unsigned long)b1, 2);
150
151 active_template = fastest;
152 return 0;
153}
154
155static __exit void xor_exit(void) { }
156
157MODULE_LICENSE("GPL");
158
159/* when built-in xor.o must initialize before drivers/md/md.o */
160core_initcall(calibrate_xor_blocks);
161module_exit(xor_exit);