@@ -4089,6 +4089,14 @@
Override pmtimer IOPort with a hex value.
e.g. pmtmr=0x508
+ pmu_override= [PPC] Override the PMU.
+ This option takes over the PMU facility, so it is no
+ longer usable by perf. Setting this option starts the
+ PMU counters by setting MMCR0 to 0 (the FC bit is
+ cleared). If a number is given, then MMCR1 is set to
+ that number, otherwise (e.g., 'pmu_override=on'), MMCR1
+ remains 0.
+
pm_debug_messages [SUSPEND,KNL]
Enable suspend/resume debug messages during boot up.
@@ -2428,8 +2428,24 @@ int register_power_pmu(struct power_pmu *pmu)
}
#ifdef CONFIG_PPC64
+static bool pmu_override = false;
+static unsigned long pmu_override_val;
+static void do_pmu_override(void *data)
+{
+ ppc_set_pmu_inuse(1);
+ if (pmu_override_val)
+ mtspr(SPRN_MMCR1, pmu_override_val);
+ mtspr(SPRN_MMCR0, mfspr(SPRN_MMCR0) & ~MMCR0_FC);
+}
+
static int __init init_ppc64_pmu(void)
{
+ if (cpu_has_feature(CPU_FTR_HVMODE) && pmu_override) {
+ printk(KERN_WARNING "perf: disabling perf due to pmu_override= command line option.\n");
+ on_each_cpu(do_pmu_override, NULL, 1);
+ return 0;
+ }
+
/* run through all the pmu drivers one at a time */
if (!init_power5_pmu())
return 0;
@@ -2451,4 +2467,23 @@ static int __init init_ppc64_pmu(void)
return init_generic_compat_pmu();
}
early_initcall(init_ppc64_pmu);
+
+static int __init pmu_setup(char *str)
+{
+ unsigned long val;
+
+ if (!early_cpu_has_feature(CPU_FTR_HVMODE))
+ return 0;
+
+ pmu_override = true;
+
+ if (kstrtoul(str, 0, &val))
+ val = 0;
+
+ pmu_override_val = val;
+
+ return 1;
+}
+__setup("pmu_override=", pmu_setup);
+
#endif
It can be useful in simulators (with very constrained environments) to allow some PMCs to run from boot so they can be sampled directly by a test harness, rather than having to run perf. A previous change freezes counters at boot by default, so provide a boot time option to un-freeze (plus a bit more flexibility). Cc: Athira Jajeev <atrajeev@linux.vnet.ibm.com> Cc: Madhavan Srinivasan <maddy@linux.vnet.ibm.com> Signed-off-by: Nicholas Piggin <npiggin@gmail.com> --- .../admin-guide/kernel-parameters.txt | 8 +++++ arch/powerpc/perf/core-book3s.c | 35 +++++++++++++++++++ 2 files changed, 43 insertions(+)