diff options
| author | Sebastian Andrzej Siewior <bigeasy@linutronix.de> | 2017-05-24 10:15:30 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2017-05-26 10:10:43 +0200 |
| commit | 1ba143a5216fb148211160a0ecc1f8d3f92f06bb (patch) | |
| tree | e3aa79ee7f498f6931759b5acc454ed305d8eb3f | |
| parent | 27d3b157fee0bad264eb745d5c547e2e0676f1a2 (diff) | |
| download | linux-1ba143a5216fb148211160a0ecc1f8d3f92f06bb.tar.bz2 | |
perf/x86/intel: Drop get_online_cpus() in intel_snb_check_microcode()
If intel_snb_check_microcode() is invoked via
microcode_init -> perf_check_microcode -> intel_snb_check_microcode
then get_online_cpus() is invoked nested. This works with the current
implementation of get_online_cpus() but prevents converting it to a percpu
rwsem.
intel_snb_check_microcode() is also invoked from intel_sandybridge_quirk()
unprotected.
Drop get_online_cpus() from intel_snb_check_microcode() and add it to
intel_sandybridge_quirk() so both call sites are protected.
Convert *_online_cpus() to the new interfaces while at it.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Borislav Petkov <bp@suse.de>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Borislav Petkov <bp@alien8.de>
Link: http://lkml.kernel.org/r/20170524081548.594862191@linutronix.de
| -rw-r--r-- | arch/x86/events/intel/core.c | 11 |
1 files changed, 5 insertions, 6 deletions
diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c index a6d91d4e37a1..b9174aacf42f 100644 --- a/arch/x86/events/intel/core.c +++ b/arch/x86/events/intel/core.c @@ -3410,12 +3410,10 @@ static void intel_snb_check_microcode(void) int pebs_broken = 0; int cpu; - get_online_cpus(); for_each_online_cpu(cpu) { if ((pebs_broken = intel_snb_pebs_broken(cpu))) break; } - put_online_cpus(); if (pebs_broken == x86_pmu.pebs_broken) return; @@ -3488,7 +3486,9 @@ static bool check_msr(unsigned long msr, u64 mask) static __init void intel_sandybridge_quirk(void) { x86_pmu.check_microcode = intel_snb_check_microcode; + cpus_read_lock(); intel_snb_check_microcode(); + cpus_read_unlock(); } static const struct { int id; char *name; } intel_arch_events_map[] __initconst = { @@ -4112,13 +4112,12 @@ static __init int fixup_ht_bug(void) lockup_detector_resume(); - get_online_cpus(); + cpus_read_lock(); - for_each_online_cpu(c) { + for_each_online_cpu(c) free_excl_cntrs(c); - } - put_online_cpus(); + cpus_read_unlock(); pr_info("PMU erratum BJ122, BV98, HSD29 workaround disabled, HT off\n"); return 0; } |