[PATCH V2 08/23] perf/x86: Expose CPUID enumeration bits for arch LBR

From: kan . liang
Date: Fri Jun 26 2020 - 14:24:49 EST


From: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>

The LBR capabilities of Architecture LBR are retrieved from the CPUID
enumeration once at boot time. The capabilities have to be saved for
future usage.

Several new fields are added into structure x86_pmu to indicate the
capabilities. The fields will be used in the following patches.

Signed-off-by: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
---
arch/x86/events/perf_event.h | 5 +++++
arch/x86/include/asm/perf_event.h | 40 +++++++++++++++++++++++++++++++++++++++
2 files changed, 45 insertions(+)

diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h
index d04818b..9b0e533 100644
--- a/arch/x86/events/perf_event.h
+++ b/arch/x86/events/perf_event.h
@@ -690,6 +690,11 @@ struct x86_pmu {
const int *lbr_sel_map; /* lbr_select mappings */
bool lbr_double_abort; /* duplicated lbr aborts */
bool lbr_pt_coexist; /* (LBR|BTS) may coexist with PT */
+ bool arch_lbr; /* Arch LBR supported */
+
+ union cpuid28_eax lbr_eax;
+ union cpuid28_ebx lbr_ebx;
+ union cpuid28_ecx lbr_ecx;

void (*lbr_reset)(void);
void (*lbr_read)(struct cpu_hw_events *cpuc);
diff --git a/arch/x86/include/asm/perf_event.h b/arch/x86/include/asm/perf_event.h
index e855e9c..d33cc82 100644
--- a/arch/x86/include/asm/perf_event.h
+++ b/arch/x86/include/asm/perf_event.h
@@ -142,6 +142,46 @@ union cpuid10_edx {
unsigned int full;
};

+/*
+ * Intel Architectural LBR CPUID detection/enumeration details:
+ */
+union cpuid28_eax {
+ struct {
+ /* Supported LBR depth values */
+ unsigned int lbr_depth_mask:8;
+ unsigned int reserved:22;
+ /* Deep C-state Reset */
+ unsigned int lbr_deep_c_reset:1;
+ /* IP values contain LIP */
+ unsigned int lbr_lip:1;
+ } split;
+ unsigned int full;
+};
+
+union cpuid28_ebx {
+ struct {
+ /* CPL Filtering Supported */
+ unsigned int lbr_cpl:1;
+ /* Branch Filtering Supported */
+ unsigned int lbr_filter:1;
+ /* Call-stack Mode Supported */
+ unsigned int lbr_call_stack:1;
+ } split;
+ unsigned int full;
+};
+
+union cpuid28_ecx {
+ struct {
+ /* Mispredict Bit Supported */
+ unsigned int lbr_mispred:1;
+ /* Timed LBRs Supported */
+ unsigned int lbr_timed_lbr:1;
+ /* Branch Type Field Supported */
+ unsigned int lbr_br_type:1;
+ } split;
+ unsigned int full;
+};
+
struct x86_pmu_capability {
int version;
int num_counters_gp;
--
2.7.4