From 0a4b4327ce867e3ac1b3ad15f4d2b686b516b3a2 Mon Sep 17 00:00:00 2001 From: Nicholas Piggin Date: Tue, 23 Nov 2021 19:51:50 +1000 Subject: powerpc/64s: Implement PMU override command line option 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). Signed-off-by: Nicholas Piggin Reviewed-by: Athira Jajeev Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20211123095231.1036501-13-npiggin@gmail.com --- Documentation/admin-guide/kernel-parameters.txt | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'Documentation') diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 9725c546a0d4..2711ddb4835a 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -4144,6 +4144,14 @@ 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. -- cgit v1.2.3