diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 8e84ee8205bd..b2442d173469 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -1541,6 +1541,10 @@ Format: { "fix" } Permit 'security.evm' to be updated regardless of current integrity status. + export_pmu_events + [KNL,ARM64] Sets the PMU export bit (PMCR_EL0.X), which enables + the exporting of events over an IMPLEMENTATION DEFINED PMU event + export bus to another device. early_page_ext [KNL,EARLY] Enforces page_ext initialization to earlier stages so cover more early boot allocations. diff --git a/Documentation/admin-guide/sysctl/kernel.rst b/Documentation/admin-guide/sysctl/kernel.rst index fa21cdd610b2..e2afeefc6bf2 100644 --- a/Documentation/admin-guide/sysctl/kernel.rst +++ b/Documentation/admin-guide/sysctl/kernel.rst @@ -286,6 +286,17 @@ domain names are in general different. For a detailed discussion see the ``hostname(1)`` man page. +export_pmu_events (arm64 only) +============================== + +Controls the PMU export bit (PMCR_EL0.X), which enables the exporting of +events over an IMPLEMENTATION DEFINED PMU event export bus to another device. + +0: disables exporting of events (default). + +1: enables exporting of events. + + firmware_config =============== diff --git a/drivers/perf/arm_pmuv3.c b/drivers/perf/arm_pmuv3.c index 0afe02f879b4..5673d6fd9227 100644 --- a/drivers/perf/arm_pmuv3.c +++ b/drivers/perf/arm_pmuv3.c @@ -325,6 +325,7 @@ GEN_PMU_FORMAT_ATTR(threshold_compare); GEN_PMU_FORMAT_ATTR(threshold); static int sysctl_perf_user_access __read_mostly; +static int sysctl_export_pmu_events __read_mostly; static bool armv8pmu_event_is_64bit(struct perf_event *event) { @@ -1053,6 +1054,17 @@ static int armv8pmu_set_event_filter(struct hw_perf_event *event, return 0; } +static int __init export_pmu_events(char *str) +{ + /* Enable exporting of pmu events at early bootup with kernel + * arguments. + */ + sysctl_export_pmu_events = 1; + return 0; +} + +early_param("export_pmu_events", export_pmu_events); + static void armv8pmu_reset(void *info) { struct arm_pmu *cpu_pmu = (struct arm_pmu *)info; @@ -1077,6 +1089,9 @@ static void armv8pmu_reset(void *info) if (armv8pmu_has_long_event(cpu_pmu)) pmcr |= ARMV8_PMU_PMCR_LP; + if (sysctl_export_pmu_events) + pmcr |= ARMV8_PMU_PMCR_X; + armv8pmu_pmcr_write(pmcr); } @@ -1280,6 +1295,15 @@ static struct ctl_table armv8_pmu_sysctl_table[] = { .extra1 = SYSCTL_ZERO, .extra2 = SYSCTL_ONE, }, + { + .procname = "export_pmu_events", + .data = &sysctl_export_pmu_events, + .maxlen = sizeof(unsigned int), + .mode = 0644, + .proc_handler = proc_dointvec_minmax, + .extra1 = SYSCTL_ZERO, + .extra2 = SYSCTL_ONE, + }, }; static void armv8_pmu_register_sysctl_table(void)