Commit-ID: 1ba143a5216fb148211160a0ecc1f8d3f92f06bb Gitweb: http://git.kernel.org/tip/1ba143a5216fb148211160a0ecc1f8d3f92f06bb Author: Sebastian Andrzej Siewior <[email protected]> AuthorDate: Wed, 24 May 2017 10:15:30 +0200 Committer: Thomas Gleixner <[email protected]> CommitDate: Fri, 26 May 2017 10:10:43 +0200
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 <[email protected]> Signed-off-by: Thomas Gleixner <[email protected]> Acked-by: Ingo Molnar <[email protected]> Acked-by: Borislav Petkov <[email protected]> Cc: Paul E. McKenney <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Steven Rostedt <[email protected]> Cc: Borislav Petkov <[email protected]> Link: http://lkml.kernel.org/r/[email protected] --- arch/x86/events/intel/core.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c index a6d91d4..b9174aa 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; }
