diff options
Diffstat (limited to 'patches/0019-perf-x86-intel-Drop-get_online_cpus-in-intel_snb_che.patch')
| -rw-r--r-- | patches/0019-perf-x86-intel-Drop-get_online_cpus-in-intel_snb_che.patch | 81 |
1 files changed, 81 insertions, 0 deletions
diff --git a/patches/0019-perf-x86-intel-Drop-get_online_cpus-in-intel_snb_che.patch b/patches/0019-perf-x86-intel-Drop-get_online_cpus-in-intel_snb_che.patch new file mode 100644 index 000000000000..ae066c92721a --- /dev/null +++ b/patches/0019-perf-x86-intel-Drop-get_online_cpus-in-intel_snb_che.patch @@ -0,0 +1,81 @@ +From 1ba143a5216fb148211160a0ecc1f8d3f92f06bb Mon Sep 17 00:00:00 2001 +From: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +Date: Wed, 24 May 2017 10:15:30 +0200 +Subject: [PATCH 19/32] 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 +--- + 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 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; + } +-- +2.11.0 + |