[PATCH v4 02/11] perf/x86/lbr: Simplify the exposure check for the LBR_INFO registers

Like Xu
2021-03-14T16:01:10Z

If the platform supports LBR_INFO register, the x86_pmu.lbr_info will
be assigned in intel_pmu_?_lbr_init_?() and it's safe to expose LBR_INFO
in the x86_perf_get_lbr() directly, instead of relying on lbr_format check.

Also Architectural LBR has IA32_LBR_x_INFO instead of LBR_FORMAT_INFO_x
to hold metadata for the operation, including mispredict, TSX, and
elapsed cycle time information.

Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Ingo Molnar <mingo@redhat.com>
Signed-off-by: Like Xu <like.xu@linux.intel.com>
Reviewed-by: Kan Liang <kan.liang@linux.intel.com>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
---
arch/x86/events/intel/lbr.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/arch/x86/events/intel/lbr.c b/arch/x86/events/intel/lbr.c
index 21890dacfcfe..355ea70f1879 100644
--- a/arch/x86/events/intel/lbr.c
+++ b/arch/x86/events/intel/lbr.c
@@ -1832,12 +1832,10 @@ void __init intel_pmu_arch_lbr_init(void)
*/
int x86_perf_get_lbr(struct x86_pmu_lbr *lbr)
{
- int lbr_fmt = x86_pmu.intel_cap.lbr_format;
-
lbr->nr = x86_pmu.lbr_nr;
lbr->from = x86_pmu.lbr_from;
lbr->to = x86_pmu.lbr_to;
- lbr->info = (lbr_fmt == LBR_FORMAT_INFO) ? x86_pmu.lbr_info : 0;
+ lbr->info = x86_pmu.lbr_info;

return 0;
}
--
2.29.2