diff options
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/events/intel/pt.c | 74 | ||||
| -rw-r--r-- | arch/x86/events/intel/pt.h | 1 |
2 files changed, 73 insertions, 2 deletions
diff --git a/arch/x86/events/intel/pt.c b/arch/x86/events/intel/pt.c index 354e9ff2978c..ae8324d65e61 100644 --- a/arch/x86/events/intel/pt.c +++ b/arch/x86/events/intel/pt.c @@ -28,6 +28,7 @@ #include <asm/insn.h> #include <asm/io.h> #include <asm/intel_pt.h> +#include <asm/intel-family.h> #include "../perf_event.h" #include "pt.h" @@ -98,6 +99,7 @@ static struct attribute_group pt_cap_group = { .name = "caps", }; +PMU_FORMAT_ATTR(pt, "config:0" ); PMU_FORMAT_ATTR(cyc, "config:1" ); PMU_FORMAT_ATTR(pwr_evt, "config:4" ); PMU_FORMAT_ATTR(fup_on_ptw, "config:5" ); @@ -105,11 +107,13 @@ PMU_FORMAT_ATTR(mtc, "config:9" ); PMU_FORMAT_ATTR(tsc, "config:10" ); PMU_FORMAT_ATTR(noretcomp, "config:11" ); PMU_FORMAT_ATTR(ptw, "config:12" ); +PMU_FORMAT_ATTR(branch, "config:13" ); PMU_FORMAT_ATTR(mtc_period, "config:14-17" ); PMU_FORMAT_ATTR(cyc_thresh, "config:19-22" ); PMU_FORMAT_ATTR(psb_period, "config:24-27" ); static struct attribute *pt_formats_attr[] = { + &format_attr_pt.attr, &format_attr_cyc.attr, &format_attr_pwr_evt.attr, &format_attr_fup_on_ptw.attr, @@ -117,6 +121,7 @@ static struct attribute *pt_formats_attr[] = { &format_attr_tsc.attr, &format_attr_noretcomp.attr, &format_attr_ptw.attr, + &format_attr_branch.attr, &format_attr_mtc_period.attr, &format_attr_cyc_thresh.attr, &format_attr_psb_period.attr, @@ -197,6 +202,19 @@ static int __init pt_pmu_hw_init(void) pt_pmu.tsc_art_den = eax; } + /* model-specific quirks */ + switch (boot_cpu_data.x86_model) { + case INTEL_FAM6_BROADWELL_CORE: + case INTEL_FAM6_BROADWELL_XEON_D: + case INTEL_FAM6_BROADWELL_GT3E: + case INTEL_FAM6_BROADWELL_X: + /* not setting BRANCH_EN will #GP, erratum BDM106 */ + pt_pmu.branch_en_always_on = true; + break; + default: + break; + } + if (boot_cpu_has(X86_FEATURE_VMX)) { /* * Intel SDM, 36.5 "Tracing post-VMXON" says that @@ -263,8 +281,20 @@ fail: #define RTIT_CTL_PTW (RTIT_CTL_PTW_EN | \ RTIT_CTL_FUP_ON_PTW) -#define PT_CONFIG_MASK (RTIT_CTL_TSC_EN | \ +/* + * Bit 0 (TraceEn) in the attr.config is meaningless as the + * corresponding bit in the RTIT_CTL can only be controlled + * by the driver; therefore, repurpose it to mean: pass + * through the bit that was previously assumed to be always + * on for PT, thereby allowing the user to *not* set it if + * they so wish. See also pt_event_valid() and pt_config(). + */ +#define RTIT_CTL_PASSTHROUGH RTIT_CTL_TRACEEN + +#define PT_CONFIG_MASK (RTIT_CTL_TRACEEN | \ + RTIT_CTL_TSC_EN | \ RTIT_CTL_DISRETC | \ + RTIT_CTL_BRANCH_EN | \ RTIT_CTL_CYC_PSB | \ RTIT_CTL_MTC | \ RTIT_CTL_PWR_EVT_EN | \ @@ -332,6 +362,33 @@ static bool pt_event_valid(struct perf_event *event) return false; } + /* + * Setting bit 0 (TraceEn in RTIT_CTL MSR) in the attr.config + * clears the assomption that BranchEn must always be enabled, + * as was the case with the first implementation of PT. + * If this bit is not set, the legacy behavior is preserved + * for compatibility with the older userspace. + * + * Re-using bit 0 for this purpose is fine because it is never + * directly set by the user; previous attempts at setting it in + * the attr.config resulted in -EINVAL. + */ + if (config & RTIT_CTL_PASSTHROUGH) { + /* + * Disallow not setting BRANCH_EN where BRANCH_EN is + * always required. + */ + if (pt_pmu.branch_en_always_on && + !(config & RTIT_CTL_BRANCH_EN)) + return false; + } else { + /* + * Disallow BRANCH_EN without the PASSTHROUGH. + */ + if (config & RTIT_CTL_BRANCH_EN) + return false; + } + return true; } @@ -420,7 +477,20 @@ static void pt_config(struct perf_event *event) } reg = pt_config_filters(event); - reg |= RTIT_CTL_TOPA | RTIT_CTL_BRANCH_EN | RTIT_CTL_TRACEEN; + reg |= RTIT_CTL_TOPA | RTIT_CTL_TRACEEN; + + /* + * Previously, we had BRANCH_EN on by default, but now that PT has + * grown features outside of branch tracing, it is useful to allow + * the user to disable it. Setting bit 0 in the event's attr.config + * allows BRANCH_EN to pass through instead of being always on. See + * also the comment in pt_event_valid(). + */ + if (event->attr.config & BIT(0)) { + reg |= event->attr.config & RTIT_CTL_BRANCH_EN; + } else { + reg |= RTIT_CTL_BRANCH_EN; + } if (!event->attr.exclude_kernel) reg |= RTIT_CTL_OS; diff --git a/arch/x86/events/intel/pt.h b/arch/x86/events/intel/pt.h index b528e8f373e4..0eb41d07b79a 100644 --- a/arch/x86/events/intel/pt.h +++ b/arch/x86/events/intel/pt.h @@ -110,6 +110,7 @@ struct pt_pmu { struct pmu pmu; u32 caps[PT_CPUID_REGS_NUM * PT_CPUID_LEAVES]; bool vmx; + bool branch_en_always_on; unsigned long max_nonturbo_ratio; unsigned int tsc_art_num; unsigned int tsc_art_den; |