| // 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 optimzation */ |
| 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); |