[PATCH 15/15 -tip] x86: Add cpufeature for ancient performance monitoring

[Jaswinder Singh Rajput <jaswinder@kernel.org>]

X86_FEATURE_ARCH_PERFMON uses almost different MSRs as compare to
ancient performance monitoring, so introduced X86_FEATURE_PERFMON
to friendly access ancient performance monitor MSRs:

X86_FEATURE_PERFMON : performance monitoring for !X86_FEATURE_ARCH_PERFMON

Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>
---
 arch/x86/include/asm/cpufeature.h |    1 +
 arch/x86/kernel/cpu/amd.c         |    2 ++
 arch/x86/kernel/cpu/intel.c       |    4 +++-
 3 files changed, 6 insertions(+), 1 deletions(-)

diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h
index b91cb47..f660e99 100644
--- a/arch/x86/include/asm/cpufeature.h
+++ b/arch/x86/include/asm/cpufeature.h
@@ -169,6 +169,7 @@
 #define X86_FEATURE_MM_CFG 	(7*32+ 14) /* MM configuration		*/
 #define X86_FEATURE_BUS_CFG 	(7*32+ 15) /* Bus configuration		*/
 #define X86_FEATURE_PERF_FREQ 	(7*32+ 16) /* Performance frequency	*/
+#define X86_FEATURE_PERFMON 	(7*32+ 17) /* Performance monitoring	*/
 
 /* Virtualization flags: Linux defined */
 #define X86_FEATURE_TPR_SHADOW  (8*32+ 0) /* Intel TPR Shadow */
diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index 4b7f7dc..849d794 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -481,6 +481,8 @@ static void __cpuinit init_amd(struct cpuinfo_x86 *c)
 	if (c->x86 >= 7) {				/* K7+		*/
 		/* MSRC001_0015 Hardware Configuration Register (HWCR)	*/
 		set_cpu_cap(c, X86_FEATURE_HW_CFG);
+		/* Performance monitoring support			*/
+		set_cpu_cap(c, X86_FEATURE_PERFMON);
 	}
 	if (c->x86 >= 8) {				/* K8+		*/
 		/*
diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index 9c5169c..e3ce8c6 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -310,7 +310,9 @@ static void __cpuinit init_intel(struct cpuinfo_x86 *c)
 		/* Check for version and the number of counters */
 		if ((eax & 0xff) && (((eax>>8) & 0xff) > 1))
 			set_cpu_cap(c, X86_FEATURE_ARCH_PERFMON);
-	}
+	} else if (c->x86 >= 5)
+		/* ancient performance monitoring support */
+		set_cpu_cap(c, X86_FEATURE_PERFMON);
 
 	if (cpu_has_xmm2)
 		set_cpu_cap(c, X86_FEATURE_LFENCE_RDTSC);
-- 
1.6.0.6