diff options
Diffstat (limited to 'crypto/xor.c')
| -rw-r--r-- | crypto/xor.c | 176 |
1 files changed, 176 insertions, 0 deletions
diff --git a/crypto/xor.c b/crypto/xor.c new file mode 100644 index 0000000000..8e72e5d5db --- /dev/null +++ b/crypto/xor.c @@ -0,0 +1,176 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * xor.c : Multiple Devices driver for Linux + * + * Copyright (C) 1996, 1997, 1998, 1999, 2000, + * Ingo Molnar, Matti Aarnio, Jakub Jelinek, Richard Henderson. + * + * Dispatch optimized RAID-5 checksumming functions. + */ + +#define BH_TRACE 0 +#include <linux/module.h> +#include <linux/gfp.h> +#include <linux/raid/xor.h> +#include <linux/jiffies.h> +#include <linux/preempt.h> +#include <asm/xor.h> + +#ifndef XOR_SELECT_TEMPLATE +#define XOR_SELECT_TEMPLATE(x) (x) +#endif + +/* The xor routines to use. */ +static struct xor_block_template *active_template; + +void +xor_blocks(unsigned int src_count, unsigned int bytes, void *dest, void **srcs) +{ + unsigned long *p1, *p2, *p3, *p4; + + p1 = (unsigned long *) srcs[0]; + if (src_count == 1) { + active_template->do_2(bytes, dest, p1); + return; + } + + p2 = (unsigned long *) srcs[1]; + if (src_count == 2) { + active_template->do_3(bytes, dest, p1, p2); + return; + } + + p3 = (unsigned long *) srcs[2]; + if (src_count == 3) { + active_template->do_4(bytes, dest, p1, p2, p3); + return; + } + + p4 = (unsigned long *) srcs[3]; + active_template->do_5(bytes, dest, p1, p2, p3, p4); +} +EXPORT_SYMBOL(xor_blocks); + +/* Set of all registered templates. */ +static struct xor_block_template *__initdata template_list; + +#ifndef MODULE +static void __init do_xor_register(struct xor_block_template *tmpl) +{ + tmpl->next = template_list; + template_list = tmpl; +} + +static int __init register_xor_blocks(void) +{ + active_template = XOR_SELECT_TEMPLATE(NULL); + + if (!active_template) { +#define xor_speed do_xor_register + // register all the templates and pick the first as the default + XOR_TRY_TEMPLATES; +#undef xor_speed + active_template = template_list; + } + return 0; +} +#endif + +#define BENCH_SIZE 4096 +#define REPS 800U + +static void __init +do_xor_speed(struct xor_block_template *tmpl, void *b1, void *b2) +{ + int speed; + int i, j; + ktime_t min, start, diff; + + tmpl->next = template_list; + template_list = tmpl; + + preempt_disable(); + + min = (ktime_t)S64_MAX; + for (i = 0; i < 3; i++) { + start = ktime_get(); + for (j = 0; j < REPS; j++) { + mb(); /* prevent loop optimization */ + tmpl->do_2(BENCH_SIZE, b1, b2); + mb(); + } + diff = ktime_sub(ktime_get(), start); + if (diff < min) + min = diff; + } + + preempt_enable(); + + // bytes/ns == GB/s, multiply by 1000 to get MB/s [not MiB/s] + if (!min) + min = 1; + speed = (1000 * REPS * BENCH_SIZE) / (unsigned int)ktime_to_ns(min); + tmpl->speed = speed; + + pr_info(" %-16s: %5d MB/sec\n", tmpl->name, speed); +} + +static int __init +calibrate_xor_blocks(void) +{ + void *b1, *b2; + struct xor_block_template *f, *fastest; + + fastest = XOR_SELECT_TEMPLATE(NULL); + + if (fastest) { + printk(KERN_INFO "xor: automatically using best " + "checksumming function %-10s\n", + fastest->name); + goto out; + } + + b1 = (void *) __get_free_pages(GFP_KERNEL, 2); + if (!b1) { + printk(KERN_WARNING "xor: Yikes! No memory available.\n"); + return -ENOMEM; + } + b2 = b1 + 2*PAGE_SIZE + BENCH_SIZE; + + /* + * If this arch/cpu has a short-circuited selection, don't loop through + * all the possible functions, just test the best one + */ + +#define xor_speed(templ) do_xor_speed((templ), b1, b2) + + printk(KERN_INFO "xor: measuring software checksum speed\n"); + template_list = NULL; + XOR_TRY_TEMPLATES; + fastest = template_list; + for (f = fastest; f; f = f->next) + if (f->speed > fastest->speed) + fastest = f; + + pr_info("xor: using function: %s (%d MB/sec)\n", + fastest->name, fastest->speed); + +#undef xor_speed + + free_pages((unsigned long)b1, 2); +out: + active_template = fastest; + return 0; +} + +static __exit void xor_exit(void) { } + +MODULE_LICENSE("GPL"); + +#ifndef MODULE +/* when built-in xor.o must initialize before drivers/md/md.o */ +core_initcall(register_xor_blocks); +#endif + +module_init(calibrate_xor_blocks); +module_exit(xor_exit); |