perf_counter, x86: remove X86_FEATURE_ARCH_PERFMON flag for AMD cpus

X86_FEATURE_ARCH_PERFMON is an Intel hardware feature that does not
work on AMD CPUs. The flag is now only used in Intel specific code
(especially initialization).

[ Impact: refactor code ]
Signed-off-by: Robert Richter <robert.richter@amd.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1241002046-8832-2-git-send-email-robert.richter@amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/kernel/cpu/amd.c

@@ -420,10 +420,6 @@ static void __cpuinit init_amd(struct cpuinfo_x86 *c)
 	if (c->x86 >= 6)
 		set_cpu_cap(c, X86_FEATURE_FXSAVE_LEAK);
 
-	/* Enable Performance counter for K7 and later */
-	if (c->x86 > 6 && c->x86 <= 0x11)
-		set_cpu_cap(c, X86_FEATURE_ARCH_PERFMON);
-
 	if (!c->x86_model_id[0]) {
 		switch (c->x86) {
 		case 0xf:

arch/x86/kernel/cpu/perf_counter.c

@@ -949,6 +949,9 @@ static struct pmc_x86_ops *pmc_intel_init(void)
 	unsigned int unused;
 	unsigned int ebx;
 
+	if (!cpu_has(&boot_cpu_data, X86_FEATURE_ARCH_PERFMON))
+		return NULL;
+
 	/*
 	 * Check whether the Architectural PerfMon supports
 	 * Branch Misses Retired Event or not.
@@ -987,9 +990,6 @@ static struct pmc_x86_ops *pmc_amd_init(void)
 
 void __init init_hw_perf_counters(void)
 {
-	if (!cpu_has(&boot_cpu_data, X86_FEATURE_ARCH_PERFMON))
-		return;
-
 	switch (boot_cpu_data.x86_vendor) {
 	case X86_VENDOR_INTEL:
 		pmc_ops = pmc_intel_init();