xor: move to lib/raid/

Move the RAID XOR code to lib/raid/ as it has nothing to do with the
crypto API.

Link: https://lkml.kernel.org/r/20260327061704.3707577-6-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Eric Biggers <ebiggers@kernel.org>
Tested-by: Eric Biggers <ebiggers@kernel.org>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: "Borislav Petkov (AMD)" <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chris Mason <clm@fb.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: David Sterba <dsterba@suse.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jason A. Donenfeld <jason@zx2c4.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Li Nan <linan122@huawei.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Magnus Lindholm <linmag7@gmail.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Richard Henderson <richard.henderson@linaro.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Song Liu <song@kernel.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Ted Ts'o <tytso@mit.edu>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

4 files changed, 188 insertions, 0 deletions

diff --git a/lib/raid/Kconfig b/lib/raid/Kconfig
new file mode 100644
index 000000000000..01b73a1c303f
--- /dev/null
+++ b/lib/raid/Kconfig
@@ -0,0 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0
+
+config XOR_BLOCKS
+	tristate
diff --git a/lib/raid/Makefile b/lib/raid/Makefile
new file mode 100644
index 000000000000..3540fe846dc4
--- /dev/null
+++ b/lib/raid/Makefile
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0
+
+obj-y				+= xor/
diff --git a/lib/raid/xor/Makefile b/lib/raid/xor/Makefile
new file mode 100644
index 000000000000..7bca0ce8e90a
--- /dev/null
+++ b/lib/raid/xor/Makefile
@@ -0,0 +1,5 @@
+# SPDX-License-Identifier: GPL-2.0
+
+obj-$(CONFIG_XOR_BLOCKS)	+= xor.o
+
+xor-y				+= xor-core.o
diff --git a/lib/raid/xor/xor-core.c b/lib/raid/xor/xor-core.c
new file mode 100644
index 000000000000..df530ddc9f06
--- /dev/null
+++ b/lib/raid/xor/xor-core.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;
+
+	WARN_ON_ONCE(!in_task() || irqs_disabled() || softirq_count());
+
+	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;
+	unsigned long reps;
+	ktime_t min, start, t0;
+
+	tmpl->next = template_list;
+	template_list = tmpl;
+
+	preempt_disable();
+
+	reps = 0;
+	t0 = ktime_get();
+	/* delay start until time has advanced */
+	while ((start = ktime_get()) == t0)
+		cpu_relax();
+	do {
+		mb(); /* prevent loop optimization */
+		tmpl->do_2(BENCH_SIZE, b1, b2);
+		mb();
+	} while (reps++ < REPS || (t0 = ktime_get()) == start);
+	min = ktime_sub(t0, start);
+
+	preempt_enable();
+
+	// bytes/ns == GB/s, multiply by 1000 to get MB/s [not MiB/s]
+	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_DESCRIPTION("RAID-5 checksumming functions");
+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);