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, 162 insertions, 0 deletions

diff --git a/lib/raid6/raid6sse1.c b/lib/raid6/raid6sse1.c
new file mode 100644
index 000000000000..b274dd5eab8f
--- /dev/null
+++ b/lib/raid6/raid6sse1.c
@@ -0,0 +1,162 @@
+/* -*- linux-c -*- ------------------------------------------------------- *
+ *
+ *   Copyright 2002 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.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * raid6sse1.c
+ *
+ * SSE-1/MMXEXT implementation of RAID-6 syndrome functions
+ *
+ * This is really an MMX implementation, but it requires SSE-1 or
+ * AMD MMXEXT for prefetch support and a few other features.  The
+ * support for nontemporal memory accesses is enough to make this
+ * worthwhile as a separate implementation.
+ */
+
+#if defined(__i386__) && !defined(__arch_um__)
+
+#include <linux/raid/pq.h>
+#include "raid6x86.h"
+
+/* Defined in raid6mmx.c */
+extern const struct raid6_mmx_constants {
+        u64 x1d;
+} raid6_mmx_constants;
+
+static int raid6_have_sse1_or_mmxext(void)
+{
+        /* Not really boot_cpu but "all_cpus" */
+        return boot_cpu_has(X86_FEATURE_MMX) &&
+                (boot_cpu_has(X86_FEATURE_XMM) ||
+                 boot_cpu_has(X86_FEATURE_MMXEXT));
+}
+
+/*
+ * Plain SSE1 implementation
+ */
+static void raid6_sse11_gen_syndrome(int disks, size_t bytes, void **ptrs)
+{
+        u8 **dptr = (u8 **)ptrs;
+        u8 *p, *q;
+        int d, z, z0;
+
+        z0 = disks - 3;         /* Highest data disk */
+        p = dptr[z0+1];         /* XOR parity */
+        q = dptr[z0+2];         /* RS syndrome */
+
+        kernel_fpu_begin();
+
+        asm volatile("movq %0,%%mm0" : : "m" (raid6_mmx_constants.x1d));
+        asm volatile("pxor %mm5,%mm5"); /* Zero temp */
+
+        for ( d = 0 ; d < bytes ; d += 8 ) {
+                asm volatile("prefetchnta %0" : : "m" (dptr[z0][d]));
+                asm volatile("movq %0,%%mm2" : : "m" (dptr[z0][d])); /* P[0] */
+                asm volatile("prefetchnta %0" : : "m" (dptr[z0-1][d]));
+                asm volatile("movq %mm2,%mm4"); /* Q[0] */
+                asm volatile("movq %0,%%mm6" : : "m" (dptr[z0-1][d]));
+                for ( z = z0-2 ; z >= 0 ; z-- ) {
+                        asm volatile("prefetchnta %0" : : "m" (dptr[z][d]));
+                        asm volatile("pcmpgtb %mm4,%mm5");
+                        asm volatile("paddb %mm4,%mm4");
+                        asm volatile("pand %mm0,%mm5");
+                        asm volatile("pxor %mm5,%mm4");
+                        asm volatile("pxor %mm5,%mm5");
+                        asm volatile("pxor %mm6,%mm2");
+                        asm volatile("pxor %mm6,%mm4");
+                        asm volatile("movq %0,%%mm6" : : "m" (dptr[z][d]));
+                }
+                asm volatile("pcmpgtb %mm4,%mm5");
+                asm volatile("paddb %mm4,%mm4");
+                asm volatile("pand %mm0,%mm5");
+                asm volatile("pxor %mm5,%mm4");
+                asm volatile("pxor %mm5,%mm5");
+                asm volatile("pxor %mm6,%mm2");
+                asm volatile("pxor %mm6,%mm4");
+
+                asm volatile("movntq %%mm2,%0" : "=m" (p[d]));
+                asm volatile("movntq %%mm4,%0" : "=m" (q[d]));
+        }
+
+        asm volatile("sfence" : : : "memory");
+        kernel_fpu_end();
+}
+
+const struct raid6_calls raid6_sse1x1 = {
+        raid6_sse11_gen_syndrome,
+        raid6_have_sse1_or_mmxext,
+        "sse1x1",
+        1                       /* Has cache hints */
+};
+
+/*
+ * Unrolled-by-2 SSE1 implementation
+ */
+static void raid6_sse12_gen_syndrome(int disks, size_t bytes, void **ptrs)
+{
+        u8 **dptr = (u8 **)ptrs;
+        u8 *p, *q;
+        int d, z, z0;
+
+        z0 = disks - 3;         /* Highest data disk */
+        p = dptr[z0+1];         /* XOR parity */
+        q = dptr[z0+2];         /* RS syndrome */
+
+        kernel_fpu_begin();
+
+        asm volatile("movq %0,%%mm0" : : "m" (raid6_mmx_constants.x1d));
+        asm volatile("pxor %mm5,%mm5"); /* Zero temp */
+        asm volatile("pxor %mm7,%mm7"); /* Zero temp */
+
+        /* We uniformly assume a single prefetch covers at least 16 bytes */
+        for ( d = 0 ; d < bytes ; d += 16 ) {
+                asm volatile("prefetchnta %0" : : "m" (dptr[z0][d]));
+                asm volatile("movq %0,%%mm2" : : "m" (dptr[z0][d])); /* P[0] */
+                asm volatile("movq %0,%%mm3" : : "m" (dptr[z0][d+8])); /* P[1] */
+                asm volatile("movq %mm2,%mm4"); /* Q[0] */
+                asm volatile("movq %mm3,%mm6"); /* Q[1] */
+                for ( z = z0-1 ; z >= 0 ; z-- ) {
+                        asm volatile("prefetchnta %0" : : "m" (dptr[z][d]));
+                        asm volatile("pcmpgtb %mm4,%mm5");
+                        asm volatile("pcmpgtb %mm6,%mm7");
+                        asm volatile("paddb %mm4,%mm4");
+                        asm volatile("paddb %mm6,%mm6");
+                        asm volatile("pand %mm0,%mm5");
+                        asm volatile("pand %mm0,%mm7");
+                        asm volatile("pxor %mm5,%mm4");
+                        asm volatile("pxor %mm7,%mm6");
+                        asm volatile("movq %0,%%mm5" : : "m" (dptr[z][d]));
+                        asm volatile("movq %0,%%mm7" : : "m" (dptr[z][d+8]));
+                        asm volatile("pxor %mm5,%mm2");
+                        asm volatile("pxor %mm7,%mm3");
+                        asm volatile("pxor %mm5,%mm4");
+                        asm volatile("pxor %mm7,%mm6");
+                        asm volatile("pxor %mm5,%mm5");
+                        asm volatile("pxor %mm7,%mm7");
+                }
+                asm volatile("movntq %%mm2,%0" : "=m" (p[d]));
+                asm volatile("movntq %%mm3,%0" : "=m" (p[d+8]));
+                asm volatile("movntq %%mm4,%0" : "=m" (q[d]));
+                asm volatile("movntq %%mm6,%0" : "=m" (q[d+8]));
+        }
+
+        asm volatile("sfence" : :: "memory");
+        kernel_fpu_end();
+}
+
+const struct raid6_calls raid6_sse1x2 = {
+        raid6_sse12_gen_syndrome,
+        raid6_have_sse1_or_mmxext,
+        "sse1x2",
+        1                       /* Has cache hints */
+};
+
+#endif