lib/raid6: Add AVX2 optimized recovery functions

Optimize RAID6 recovery functions to take advantage of
the 256-bit YMM integer instructions introduced in AVX2.

The patch was tested and benchmarked before submission.
However hardware is not yet released so benchmark numbers
cannot be reported.

Acked-by: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Jim Kukunas <james.t.kukunas@linux.intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>

5 files changed, 341 insertions, 7 deletions

diff --git a/lib/raid6/Makefile b/lib/raid6/Makefile
index de06dfe165b8..8c2e22bef661 100644
--- a/lib/raid6/Makefile
+++ b/lib/raid6/Makefile
@@ -1,6 +1,6 @@
 obj-$(CONFIG_RAID6_PQ)  += raid6_pq.o
 
-raid6_pq-y      += algos.o recov.o recov_ssse3.o tables.o int1.o int2.o int4.o \
+raid6_pq-y      += algos.o recov.o recov_ssse3.o recov_avx2.o tables.o int1.o int2.o int4.o \
                    int8.o int16.o int32.o altivec1.o altivec2.o altivec4.o \
                    altivec8.o mmx.o sse1.o sse2.o
 hostprogs-y     += mktables
diff --git a/lib/raid6/algos.c b/lib/raid6/algos.c
index 589f5f50ad2e..8b7f55cadb45 100644
--- a/lib/raid6/algos.c
+++ b/lib/raid6/algos.c
@@ -72,6 +72,9 @@ EXPORT_SYMBOL_GPL(raid6_datap_recov);
 
 const struct raid6_recov_calls *const raid6_recov_algos[] = {
 #if (defined(__i386__) || defined(__x86_64__)) && !defined(__arch_um__)
+#ifdef CONFIG_AS_AVX2
+        &raid6_recov_avx2,
+#endif
         &raid6_recov_ssse3,
 #endif
         &raid6_recov_intx1,
diff --git a/lib/raid6/recov_avx2.c b/lib/raid6/recov_avx2.c
new file mode 100644
index 000000000000..43a9bab91879
--- /dev/null
+++ b/lib/raid6/recov_avx2.c
@@ -0,0 +1,327 @@
+/*
+ * Copyright (C) 2012 Intel Corporation
+ * Author: Jim Kukunas <james.t.kukunas@linux.intel.com>
+ *
+ * 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; version 2
+ * of the License.
+ */
+
+#if (defined(__i386__) || defined(__x86_64__)) && !defined(__arch_um__)
+
+#if CONFIG_AS_AVX2
+
+#include <linux/raid/pq.h>
+#include "x86.h"
+
+static int raid6_has_avx2(void)
+{
+        return boot_cpu_has(X86_FEATURE_AVX2) &&
+                boot_cpu_has(X86_FEATURE_AVX);
+}
+
+static void raid6_2data_recov_avx2(int disks, size_t bytes, int faila,
+                int failb, void **ptrs)
+{
+        u8 *p, *q, *dp, *dq;
+        const u8 *pbmul;        /* P multiplier table for B data */
+        const u8 *qmul;         /* Q multiplier table (for both) */
+        const u8 x0f = 0x0f;
+
+        p = (u8 *)ptrs[disks-2];
+        q = (u8 *)ptrs[disks-1];
+
+        /* Compute syndrome with zero for the missing data pages
+           Use the dead data pages as temporary storage for
+           delta p and delta q */
+        dp = (u8 *)ptrs[faila];
+        ptrs[faila] = (void *)raid6_empty_zero_page;
+        ptrs[disks-2] = dp;
+        dq = (u8 *)ptrs[failb];
+        ptrs[failb] = (void *)raid6_empty_zero_page;
+        ptrs[disks-1] = dq;
+
+        raid6_call.gen_syndrome(disks, bytes, ptrs);
+
+        /* Restore pointer table */
+        ptrs[faila]   = dp;
+        ptrs[failb]   = dq;
+        ptrs[disks-2] = p;
+        ptrs[disks-1] = q;
+
+        /* Now, pick the proper data tables */
+        pbmul = raid6_vgfmul[raid6_gfexi[failb-faila]];
+        qmul  = raid6_vgfmul[raid6_gfinv[raid6_gfexp[faila] ^
+                raid6_gfexp[failb]]];
+
+        kernel_fpu_begin();
+
+        /* ymm0 = x0f[16] */
+        asm volatile("vpbroadcastb %0, %%ymm7" : : "m" (x0f));
+
+        while (bytes) {
+#ifdef CONFIG_X86_64
+                asm volatile("vmovdqa %0, %%ymm1" : : "m" (q[0]));
+                asm volatile("vmovdqa %0, %%ymm9" : : "m" (q[32]));
+                asm volatile("vmovdqa %0, %%ymm0" : : "m" (p[0]));
+                asm volatile("vmovdqa %0, %%ymm8" : : "m" (p[32]));
+                asm volatile("vpxor %0, %%ymm1, %%ymm1" : : "m" (dq[0]));
+                asm volatile("vpxor %0, %%ymm9, %%ymm9" : : "m" (dq[32]));
+                asm volatile("vpxor %0, %%ymm0, %%ymm0" : : "m" (dp[0]));
+                asm volatile("vpxor %0, %%ymm8, %%ymm8" : : "m" (dp[32]));
+
+                /*
+                 * 1 = dq[0]  ^ q[0]
+                 * 9 = dq[32] ^ q[32]
+                 * 0 = dp[0]  ^ p[0]
+                 * 8 = dp[32] ^ p[32]
+                 */
+
+                asm volatile("vbroadcasti128 %0, %%ymm4" : : "m" (qmul[0]));
+                asm volatile("vbroadcasti128 %0, %%ymm5" : : "m" (qmul[16]));
+
+                asm volatile("vpsraw $4, %ymm1, %ymm3");
+                asm volatile("vpsraw $4, %ymm9, %ymm12");
+                asm volatile("vpand %ymm7, %ymm1, %ymm1");
+                asm volatile("vpand %ymm7, %ymm9, %ymm9");
+                asm volatile("vpand %ymm7, %ymm3, %ymm3");
+                asm volatile("vpand %ymm7, %ymm12, %ymm12");
+                asm volatile("vpshufb %ymm9, %ymm4, %ymm14");
+                asm volatile("vpshufb %ymm1, %ymm4, %ymm4");
+                asm volatile("vpshufb %ymm12, %ymm5, %ymm15");
+                asm volatile("vpshufb %ymm3, %ymm5, %ymm5");
+                asm volatile("vpxor %ymm14, %ymm15, %ymm15");
+                asm volatile("vpxor %ymm4, %ymm5, %ymm5");
+
+                /*
+                 * 5 = qx[0]
+                 * 15 = qx[32]
+                 */
+
+                asm volatile("vbroadcasti128 %0, %%ymm4" : : "m" (pbmul[0]));
+                asm volatile("vbroadcasti128 %0, %%ymm1" : : "m" (pbmul[16]));
+                asm volatile("vpsraw $4, %ymm0, %ymm2");
+                asm volatile("vpsraw $4, %ymm8, %ymm6");
+                asm volatile("vpand %ymm7, %ymm0, %ymm3");
+                asm volatile("vpand %ymm7, %ymm8, %ymm14");
+                asm volatile("vpand %ymm7, %ymm2, %ymm2");
+                asm volatile("vpand %ymm7, %ymm6, %ymm6");
+                asm volatile("vpshufb %ymm14, %ymm4, %ymm12");
+                asm volatile("vpshufb %ymm3, %ymm4, %ymm4");
+                asm volatile("vpshufb %ymm6, %ymm1, %ymm13");
+                asm volatile("vpshufb %ymm2, %ymm1, %ymm1");
+                asm volatile("vpxor %ymm4, %ymm1, %ymm1");
+                asm volatile("vpxor %ymm12, %ymm13, %ymm13");
+
+                /*
+                 * 1  = pbmul[px[0]]
+                 * 13 = pbmul[px[32]]
+                 */
+                asm volatile("vpxor %ymm5, %ymm1, %ymm1");
+                asm volatile("vpxor %ymm15, %ymm13, %ymm13");
+
+                /*
+                 * 1 = db = DQ
+                 * 13 = db[32] = DQ[32]
+                 */
+                asm volatile("vmovdqa %%ymm1, %0" : "=m" (dq[0]));
+                asm volatile("vmovdqa %%ymm13,%0" : "=m" (dq[32]));
+                asm volatile("vpxor %ymm1, %ymm0, %ymm0");
+                asm volatile("vpxor %ymm13, %ymm8, %ymm8");
+
+                asm volatile("vmovdqa %%ymm0, %0" : "=m" (dp[0]));
+                asm volatile("vmovdqa %%ymm8, %0" : "=m" (dp[32]));
+
+                bytes -= 64;
+                p += 64;
+                q += 64;
+                dp += 64;
+                dq += 64;
+#else
+                asm volatile("vmovdqa %0, %%ymm1" : : "m" (*q));
+                asm volatile("vmovdqa %0, %%ymm0" : : "m" (*p));
+                asm volatile("vpxor %0, %%ymm1, %%ymm1" : : "m" (*dq));
+                asm volatile("vpxor %0, %%ymm0, %%ymm0" : : "m" (*dp));
+
+                /* 1 = dq ^ q;  0 = dp ^ p */
+
+                asm volatile("vbroadcasti128 %0, %%ymm4" : : "m" (qmul[0]));
+                asm volatile("vbroadcasti128 %0, %%ymm5" : : "m" (qmul[16]));
+
+                /*
+                 * 1 = dq ^ q
+                 * 3 = dq ^ p >> 4
+                 */
+                asm volatile("vpsraw $4, %ymm1, %ymm3");
+                asm volatile("vpand %ymm7, %ymm1, %ymm1");
+                asm volatile("vpand %ymm7, %ymm3, %ymm3");
+                asm volatile("vpshufb %ymm1, %ymm4, %ymm4");
+                asm volatile("vpshufb %ymm3, %ymm5, %ymm5");
+                asm volatile("vpxor %ymm4, %ymm5, %ymm5");
+
+                /* 5 = qx */
+
+                asm volatile("vbroadcasti128 %0, %%ymm4" : : "m" (pbmul[0]));
+                asm volatile("vbroadcasti128 %0, %%ymm1" : : "m" (pbmul[16]));
+
+                asm volatile("vpsraw $4, %ymm0, %ymm2");
+                asm volatile("vpand %ymm7, %ymm0, %ymm3");
+                asm volatile("vpand %ymm7, %ymm2, %ymm2");
+                asm volatile("vpshufb %ymm3, %ymm4, %ymm4");
+                asm volatile("vpshufb %ymm2, %ymm1, %ymm1");
+                asm volatile("vpxor %ymm4, %ymm1, %ymm1");
+
+                /* 1 = pbmul[px] */
+                asm volatile("vpxor %ymm5, %ymm1, %ymm1");
+                /* 1 = db = DQ */
+                asm volatile("vmovdqa %%ymm1, %0" : "=m" (dq[0]));
+
+                asm volatile("vpxor %ymm1, %ymm0, %ymm0");
+                asm volatile("vmovdqa %%ymm0, %0" : "=m" (dp[0]));
+
+                bytes -= 32;
+                p += 32;
+                q += 32;
+                dp += 32;
+                dq += 32;
+#endif
+        }
+
+        kernel_fpu_end();
+}
+
+static void raid6_datap_recov_avx2(int disks, size_t bytes, int faila,
+                void **ptrs)
+{
+        u8 *p, *q, *dq;
+        const u8 *qmul;         /* Q multiplier table */
+        const u8 x0f = 0x0f;
+
+        p = (u8 *)ptrs[disks-2];
+        q = (u8 *)ptrs[disks-1];
+
+        /* Compute syndrome with zero for the missing data page
+           Use the dead data page as temporary storage for delta q */
+        dq = (u8 *)ptrs[faila];
+        ptrs[faila] = (void *)raid6_empty_zero_page;
+        ptrs[disks-1] = dq;
+
+        raid6_call.gen_syndrome(disks, bytes, ptrs);
+
+        /* Restore pointer table */
+        ptrs[faila]   = dq;
+        ptrs[disks-1] = q;
+
+        /* Now, pick the proper data tables */
+        qmul  = raid6_vgfmul[raid6_gfinv[raid6_gfexp[faila]]];
+
+        kernel_fpu_begin();
+
+        asm volatile("vpbroadcastb %0, %%ymm7" : : "m" (x0f));
+
+        while (bytes) {
+#ifdef CONFIG_X86_64
+                asm volatile("vmovdqa %0, %%ymm3" : : "m" (dq[0]));
+                asm volatile("vmovdqa %0, %%ymm8" : : "m" (dq[32]));
+                asm volatile("vpxor %0, %%ymm3, %%ymm3" : : "m" (q[0]));
+                asm volatile("vpxor %0, %%ymm8, %%ymm8" : : "m" (q[32]));
+
+                /*
+                 * 3 = q[0] ^ dq[0]
+                 * 8 = q[32] ^ dq[32]
+                 */
+                asm volatile("vbroadcasti128 %0, %%ymm0" : : "m" (qmul[0]));
+                asm volatile("vmovapd %ymm0, %ymm13");
+                asm volatile("vbroadcasti128 %0, %%ymm1" : : "m" (qmul[16]));
+                asm volatile("vmovapd %ymm1, %ymm14");
+
+                asm volatile("vpsraw $4, %ymm3, %ymm6");
+                asm volatile("vpsraw $4, %ymm8, %ymm12");
+                asm volatile("vpand %ymm7, %ymm3, %ymm3");
+                asm volatile("vpand %ymm7, %ymm8, %ymm8");
+                asm volatile("vpand %ymm7, %ymm6, %ymm6");
+                asm volatile("vpand %ymm7, %ymm12, %ymm12");
+                asm volatile("vpshufb %ymm3, %ymm0, %ymm0");
+                asm volatile("vpshufb %ymm8, %ymm13, %ymm13");
+                asm volatile("vpshufb %ymm6, %ymm1, %ymm1");
+                asm volatile("vpshufb %ymm12, %ymm14, %ymm14");
+                asm volatile("vpxor %ymm0, %ymm1, %ymm1");
+                asm volatile("vpxor %ymm13, %ymm14, %ymm14");
+
+                /*
+                 * 1  = qmul[q[0]  ^ dq[0]]
+                 * 14 = qmul[q[32] ^ dq[32]]
+                 */
+                asm volatile("vmovdqa %0, %%ymm2" : : "m" (p[0]));
+                asm volatile("vmovdqa %0, %%ymm12" : : "m" (p[32]));
+                asm volatile("vpxor %ymm1, %ymm2, %ymm2");
+                asm volatile("vpxor %ymm14, %ymm12, %ymm12");
+
+                /*
+                 * 2  = p[0]  ^ qmul[q[0]  ^ dq[0]]
+                 * 12 = p[32] ^ qmul[q[32] ^ dq[32]]
+                 */
+
+                asm volatile("vmovdqa %%ymm1, %0" : "=m" (dq[0]));
+                asm volatile("vmovdqa %%ymm14, %0" : "=m" (dq[32]));
+                asm volatile("vmovdqa %%ymm2, %0" : "=m" (p[0]));
+                asm volatile("vmovdqa %%ymm12,%0" : "=m" (p[32]));
+
+                bytes -= 64;
+                p += 64;
+                q += 64;
+                dq += 64;
+#else
+                asm volatile("vmovdqa %0, %%ymm3" : : "m" (dq[0]));
+                asm volatile("vpxor %0, %%ymm3, %%ymm3" : : "m" (q[0]));
+
+                /* 3 = q ^ dq */
+
+                asm volatile("vbroadcasti128 %0, %%ymm0" : : "m" (qmul[0]));
+                asm volatile("vbroadcasti128 %0, %%ymm1" : : "m" (qmul[16]));
+
+                asm volatile("vpsraw $4, %ymm3, %ymm6");
+                asm volatile("vpand %ymm7, %ymm3, %ymm3");
+                asm volatile("vpand %ymm7, %ymm6, %ymm6");
+                asm volatile("vpshufb %ymm3, %ymm0, %ymm0");
+                asm volatile("vpshufb %ymm6, %ymm1, %ymm1");
+                asm volatile("vpxor %ymm0, %ymm1, %ymm1");
+
+                /* 1 = qmul[q ^ dq] */
+
+                asm volatile("vmovdqa %0, %%ymm2" : : "m" (p[0]));
+                asm volatile("vpxor %ymm1, %ymm2, %ymm2");
+
+                /* 2 = p ^ qmul[q ^ dq] */
+
+                asm volatile("vmovdqa %%ymm1, %0" : "=m" (dq[0]));
+                asm volatile("vmovdqa %%ymm2, %0" : "=m" (p[0]));
+
+                bytes -= 32;
+                p += 32;
+                q += 32;
+                dq += 32;
+#endif
+        }
+
+        kernel_fpu_end();
+}
+
+const struct raid6_recov_calls raid6_recov_avx2 = {
+        .data2 = raid6_2data_recov_avx2,
+        .datap = raid6_datap_recov_avx2,
+        .valid = raid6_has_avx2,
+#ifdef CONFIG_X86_64
+        .name = "avx2x2",
+#else
+        .name = "avx2x1",
+#endif
+        .priority = 2,
+};
+
+#else
+#warning "your version of binutils lacks AVX2 support"
+#endif
+
+#endif
diff --git a/lib/raid6/test/Makefile b/lib/raid6/test/Makefile
index c76151d94764..d919c98ce266 100644
--- a/lib/raid6/test/Makefile
+++ b/lib/raid6/test/Makefile
@@ -23,7 +23,7 @@ RANLIB	 = ranlib
 all:    raid6.a raid6test
 
 raid6.a: int1.o int2.o int4.o int8.o int16.o int32.o mmx.o sse1.o sse2.o \
-         altivec1.o altivec2.o altivec4.o altivec8.o recov.o recov_ssse3.o algos.o \
+         altivec1.o altivec2.o altivec4.o altivec8.o recov.o recov_ssse3.o recov_avx2.o algos.o \
          tables.o
          rm -f $@
          $(AR) cq $@ $^
diff --git a/lib/raid6/x86.h b/lib/raid6/x86.h
index d55d63232c55..b7595484a815 100644
--- a/lib/raid6/x86.h
+++ b/lib/raid6/x86.h
@@ -45,19 +45,23 @@ static inline void kernel_fpu_end(void)
 #define X86_FEATURE_XMM3        (4*32+ 0) /* "pni" SSE-3 */
 #define X86_FEATURE_SSSE3       (4*32+ 9) /* Supplemental SSE-3 */
 #define X86_FEATURE_AVX (4*32+28) /* Advanced Vector Extensions */
+#define X86_FEATURE_AVX2        (9*32+ 5) /* AVX2 instructions */
 #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 & 0x20) ? 0x80000001 : 1;
-        u32 ecx, edx;
+        u32 eax, ebx, ecx, edx;
+
+        eax = (flag & 0x100) ? 7 :
+                (flag & 0x20) ? 0x80000001 : 1;
+        ecx = 0;
 
         asm volatile("cpuid"
-                     : "+a" (eax), "=d" (edx), "=c" (ecx)
-                     : : "ebx");
+                     : "+a" (eax), "=b" (ebx), "=d" (edx), "+c" (ecx));
 
-        return ((flag & 0x80 ? ecx : edx) >> (flag & 31)) & 1;
+        return ((flag & 0x100 ? ebx :
+                (flag & 0x80) ? ecx : edx) >> (flag & 31)) & 1;
 }
 
 #endif /* ndef __KERNEL__ */