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>

1 files changed, 9 insertions, 5 deletions

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__ */