md: Factor out RAID6 algorithms into lib/

We'll want to use these in btrfs too.

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

1 files changed, 61 insertions, 0 deletions

diff --git a/lib/raid6/raid6x86.h b/lib/raid6/raid6x86.h
new file mode 100644
index 0000000..4c22c15
--- /dev/null
+++ b/lib/raid6/raid6x86.h
@@ -0,0 +1,61 @@
+/* ----------------------------------------------------------------------- *
+ *
+ *   Copyright 2002-2004 H. Peter Anvin - All Rights Reserved
+ *
+ *   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, Inc., 53 Temple Place Ste 330,
+ *   Boston MA 02111-1307, USA; either version 2 of the License, or
+ *   (at your option) any later version; incorporated herein by reference.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * raid6x86.h
+ *
+ * Definitions common to x86 and x86-64 RAID-6 code only
+ */
+
+#ifndef LINUX_RAID_RAID6X86_H
+#define LINUX_RAID_RAID6X86_H
+
+#if (defined(__i386__) || defined(__x86_64__)) && !defined(__arch_um__)
+
+#ifdef __KERNEL__ /* Real code */
+
+#include <asm/i387.h>
+
+#else /* Dummy code for user space testing */
+
+static inline void kernel_fpu_begin(void)
+{
+}
+
+static inline void kernel_fpu_end(void)
+{
+}
+
+#define X86_FEATURE_MMX		(0*32+23) /* Multimedia Extensions */
+#define X86_FEATURE_FXSR	(0*32+24) /* FXSAVE and FXRSTOR instructions
+					   * (fast save and restore) */
+#define X86_FEATURE_XMM		(0*32+25) /* Streaming SIMD Extensions */
+#define X86_FEATURE_XMM2	(0*32+26) /* Streaming SIMD Extensions-2 */
+#define X86_FEATURE_MMXEXT	(1*32+22) /* AMD MMX extensions */
+
+/* Should work well enough on modern CPUs for testing */
+static inline int boot_cpu_has(int flag)
+{
+	u32 eax = (flag >> 5) ? 0x80000001 : 1;
+	u32 edx;
+
+	asm volatile("cpuid"
+		     : "+a" (eax), "=d" (edx)
+		     : : "ecx", "ebx");
+
+	return (edx >> (flag & 31)) & 1;
+}
+
+#endif /* ndef __KERNEL__ */
+
+#endif
+#endif