1 files changed, 169 insertions, 0 deletions

diff --git a/kernel/crypto/xor.c b/kernel/crypto/xor.c
new file mode 100644
index 000000000..35d6b3adf
--- /dev/null
+++ b/kernel/crypto/xor.c
@@ -0,0 +1,169 @@
+/*
+ * 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.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * You should have received a copy of the GNU General Public License
+ * (for example /usr/src/linux/COPYING); if not, write to the Free
+ * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#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>
+
+/* 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;
+
+#define BENCH_SIZE (PAGE_SIZE)
+
+static void __init
+do_xor_speed(struct xor_block_template *tmpl, void *b1, void *b2)
+{
+	int speed;
+	unsigned long now, j;
+	int i, count, max;
+
+	tmpl->next = template_list;
+	template_list = tmpl;
+
+	preempt_disable();
+
+	/*
+	 * Count the number of XORs done during a whole jiffy, and use
+	 * this to calculate the speed of checksumming.  We use a 2-page
+	 * allocation to have guaranteed color L1-cache layout.
+	 */
+	max = 0;
+	for (i = 0; i < 5; i++) {
+		j = jiffies;
+		count = 0;
+		while ((now = jiffies) == j)
+			cpu_relax();
+		while (time_before(jiffies, now + 1)) {
+			mb(); /* prevent loop optimzation */
+			tmpl->do_2(BENCH_SIZE, b1, b2);
+			mb();
+			count++;
+			mb();
+		}
+		if (count > max)
+			max = count;
+	}
+
+	preempt_enable();
+
+	speed = max * (HZ * BENCH_SIZE / 1024);
+	tmpl->speed = speed;
+
+	printk(KERN_INFO "   %-10s: %5d.%03d MB/sec\n", tmpl->name,
+	       speed / 1000, speed % 1000);
+}
+
+static int __init
+calibrate_xor_blocks(void)
+{
+	void *b1, *b2;
+	struct xor_block_template *f, *fastest;
+
+	/*
+	 * Note: Since the memory is not actually used for _anything_ but to
+	 * test the XOR speed, we don't really want kmemcheck to warn about
+	 * reading uninitialized bytes here.
+	 */
+	b1 = (void *) __get_free_pages(GFP_KERNEL | __GFP_NOTRACK, 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
+	 */
+
+	fastest = NULL;
+
+#ifdef XOR_SELECT_TEMPLATE
+		fastest = XOR_SELECT_TEMPLATE(fastest);
+#endif
+
+#define xor_speed(templ)	do_xor_speed((templ), b1, b2)
+
+	if (fastest) {
+		printk(KERN_INFO "xor: automatically using best "
+				 "checksumming function:\n");
+		xor_speed(fastest);
+		goto out;
+	} else {
+		printk(KERN_INFO "xor: measuring software checksum speed\n");
+		XOR_TRY_TEMPLATES;
+		fastest = template_list;
+		for (f = fastest; f; f = f->next)
+			if (f->speed > fastest->speed)
+				fastest = f;
+	}
+
+	printk(KERN_INFO "xor: using function: %s (%d.%03d MB/sec)\n",
+	       fastest->name, fastest->speed / 1000, fastest->speed % 1000);
+
+#undef xor_speed
+
+ out:
+	free_pages((unsigned long)b1, 2);
+
+	active_template = fastest;
+	return 0;
+}
+
+static __exit void xor_exit(void) { }
+
+MODULE_LICENSE("GPL");
+
+/* when built-in xor.o must initialize before drivers/md/md.o */
+core_initcall(calibrate_xor_blocks);
+module_exit(xor_exit);