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authorSebastian Andrzej Siewior <bigeasy@linutronix.de>2017-05-24 10:15:30 +0200
committerThomas Gleixner <tglx@linutronix.de>2017-05-26 10:10:43 +0200
commit1ba143a5216fb148211160a0ecc1f8d3f92f06bb (patch)
treee3aa79ee7f498f6931759b5acc454ed305d8eb3f /arch/x86/events/intel/core.c
parent27d3b157fee0bad264eb745d5c547e2e0676f1a2 (diff)
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
Diffstat (limited to 'arch/x86/events/intel/core.c')
-rw-r--r--arch/x86/events/intel/core.c11
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;
}