Revert "x86, amd: Disable way access filter on Piledriver CPUs" it is…

… duplicated

Revert 5e3fe67 which is
commit 2bbf0a1 upstream.

Willy pointed out that I messed up and applied this one twice to the
3.0-stable tree, so revert the second instance of it.

Reported by: Willy Tarreau <w@1wt.eu>
Cc: Andre Przywara <osp@andrep.de>
Cc: H. Peter Anvin <hpa@linux.intel.com>
Cc: CAI Qian <caiqian@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

reverted:

arch/x86/kernel/cpu/amd.c

@@ -568,20 +568,6 @@ static void __cpuinit init_amd(struct cpuinfo_x86 *c)
 		}
 	}
 
-	/*
-	 * The way access filter has a performance penalty on some workloads.
-	 * Disable it on the affected CPUs.
-	 */
-	if ((c->x86 == 0x15) &&
-	    (c->x86_model >= 0x02) && (c->x86_model < 0x20)) {
-		u64 val;
-
-		if (!rdmsrl_safe(0xc0011021, &val) && !(val & 0x1E)) {
-			val |= 0x1E;
-			checking_wrmsrl(0xc0011021, val);
-		}
-	}
-
 	cpu_detect_cache_sizes(c);
 
 	/* Multi core CPU? */