[PATCH] x86-64: x86-64 add Intel BTS cpufeature bit and detection (take 2)

Here is a small patch for x86-64 which adds a cpufeature flag and
detection code for Intel's Branch Trace Store (BTS) feature. This
feature can be found on Intel P4 and Core 2 processors among others.
It can also be used by perfmon.

changelog:
	- add CPU_FEATURE_BTS
	- add Branch Trace Store detection

signed-off-by: stephane eranian <eranian@hpl.hp.com>

Signed-off-by: Andi Kleen <ak@suse.de>

1 files changed, 2 insertions, 0 deletions

diff --git a/arch/x86_64/kernel/setup.c b/arch/x86_64/kernel/setup.c
index 619af2e2fa26..a570c81c8316 100644
--- a/arch/x86_64/kernel/setup.c
+++ b/arch/x86_64/kernel/setup.c
@@ -838,6 +838,8 @@ static void __cpuinit init_intel(struct cpuinfo_x86 *c)
         if (cpu_has_ds) {
                 unsigned int l1, l2;
                 rdmsr(MSR_IA32_MISC_ENABLE, l1, l2);
+                if (!(l1 & (1<<11)))
+                        set_bit(X86_FEATURE_BTS, c->x86_capability);
                 if (!(l1 & (1<<12)))
                         set_bit(X86_FEATURE_PEBS, c->x86_capability);
         }