From c93dc84cbe32435be3ffa2fbde355eff94955c32 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 8 Jun 2012 14:50:50 +0200 Subject: [PATCH] perf/x86: Add a microcode revision check for SNB-PEBS Recent Intel microcode resolved the SNB-PEBS issues, so conditionally enable PEBS on SNB hardware depending on the microcode revision. Thanks to Stephane for figuring out the various microcode revisions. Suggested-by: Stephane Eranian Acked-by: Borislav Petkov Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/n/tip-v3672ziwh9damwqwh1uz3krm@git.kernel.org Signed-off-by: Ingo Molnar --- arch/x86/include/asm/perf_event.h | 2 + arch/x86/kernel/cpu/perf_event.c | 21 +++++++---- arch/x86/kernel/cpu/perf_event.h | 4 +- arch/x86/kernel/cpu/perf_event_intel.c | 51 ++++++++++++++++++++++++-- arch/x86/kernel/microcode_core.c | 10 +++-- 5 files changed, 74 insertions(+), 14 deletions(-) diff --git a/arch/x86/include/asm/perf_event.h b/arch/x86/include/asm/perf_event.h index ffdf5e0991c4..c78f14a0df00 100644 --- a/arch/x86/include/asm/perf_event.h +++ b/arch/x86/include/asm/perf_event.h @@ -232,6 +232,7 @@ struct perf_guest_switch_msr { extern struct perf_guest_switch_msr *perf_guest_get_msrs(int *nr); extern void perf_get_x86_pmu_capability(struct x86_pmu_capability *cap); +extern void perf_check_microcode(void); #else static inline perf_guest_switch_msr *perf_guest_get_msrs(int *nr) { @@ -245,6 +246,7 @@ static inline void perf_get_x86_pmu_capability(struct x86_pmu_capability *cap) } static inline void perf_events_lapic_init(void) { } +static inline void perf_check_microcode(void) { } #endif #if defined(CONFIG_PERF_EVENTS) && defined(CONFIG_CPU_SUP_AMD) diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c index 3eb88ebcec5a..29557aa06dda 100644 --- a/arch/x86/kernel/cpu/perf_event.c +++ b/arch/x86/kernel/cpu/perf_event.c @@ -379,7 +379,7 @@ int x86_pmu_hw_config(struct perf_event *event) int precise = 0; /* Support for constant skid */ - if (x86_pmu.pebs_active) { + if (x86_pmu.pebs_active && !x86_pmu.pebs_broken) { precise++; /* Support for IP fixup */ @@ -1650,13 +1650,20 @@ static void x86_pmu_flush_branch_stack(void) x86_pmu.flush_branch_stack(); } +void perf_check_microcode(void) +{ + if (x86_pmu.check_microcode) + x86_pmu.check_microcode(); +} +EXPORT_SYMBOL_GPL(perf_check_microcode); + static struct pmu pmu = { .pmu_enable = x86_pmu_enable, .pmu_disable = x86_pmu_disable, - .attr_groups = x86_pmu_attr_groups, + .attr_groups = x86_pmu_attr_groups, - .event_init = x86_pmu_event_init, + .event_init = x86_pmu_event_init, .add = x86_pmu_add, .del = x86_pmu_del, @@ -1664,11 +1671,11 @@ static struct pmu pmu = { .stop = x86_pmu_stop, .read = x86_pmu_read, - .start_txn = x86_pmu_start_txn, - .cancel_txn = x86_pmu_cancel_txn, - .commit_txn = x86_pmu_commit_txn, + .start_txn = x86_pmu_start_txn, + .cancel_txn = x86_pmu_cancel_txn, + .commit_txn = x86_pmu_commit_txn, - .event_idx = x86_pmu_event_idx, + .event_idx = x86_pmu_event_idx, .flush_branch_stack = x86_pmu_flush_branch_stack, }; diff --git a/arch/x86/kernel/cpu/perf_event.h b/arch/x86/kernel/cpu/perf_event.h index 83238f2a12b2..3f5c66904355 100644 --- a/arch/x86/kernel/cpu/perf_event.h +++ b/arch/x86/kernel/cpu/perf_event.h @@ -361,6 +361,8 @@ struct x86_pmu { void (*cpu_starting)(int cpu); void (*cpu_dying)(int cpu); void (*cpu_dead)(int cpu); + + void (*check_microcode)(void); void (*flush_branch_stack)(void); /* @@ -373,7 +375,7 @@ struct x86_pmu { * Intel DebugStore bits */ int bts, pebs; - int bts_active, pebs_active; + int bts_active, pebs_active, pebs_broken; int pebs_record_size; void (*drain_pebs)(struct pt_regs *regs); struct event_constraint *pebs_constraints; diff --git a/arch/x86/kernel/cpu/perf_event_intel.c b/arch/x86/kernel/cpu/perf_event_intel.c index 2e9444c80148..5fdedb4bc3f1 100644 --- a/arch/x86/kernel/cpu/perf_event_intel.c +++ b/arch/x86/kernel/cpu/perf_event_intel.c @@ -1712,11 +1712,56 @@ static __init void intel_clovertown_quirk(void) x86_pmu.pebs_constraints = NULL; } +static int intel_snb_pebs_broken(int cpu) +{ + u32 rev = UINT_MAX; /* default to broken for unknown models */ + + switch (cpu_data(cpu).x86_model) { + case 42: /* SNB */ + rev = 0x28; + break; + + case 45: /* SNB-EP */ + switch (cpu_data(cpu).x86_mask) { + case 6: rev = 0x618; break; + case 7: rev = 0x70c; break; + } + } + + return (cpu_data(cpu).microcode < rev); +} + +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; + + /* + * Serialized by the microcode lock.. + */ + if (x86_pmu.pebs_broken) { + pr_info("PEBS enabled due to microcode update\n"); + x86_pmu.pebs_broken = 0; + } else { + pr_info("PEBS disabled due to CPU errata, please upgrade microcode\n"); + x86_pmu.pebs_broken = 1; + } +} + static __init void intel_sandybridge_quirk(void) { - printk(KERN_WARNING "PEBS disabled due to CPU errata.\n"); - x86_pmu.pebs = 0; - x86_pmu.pebs_constraints = NULL; + x86_pmu.check_microcode = intel_snb_check_microcode; + intel_snb_check_microcode(); } static const struct { int id; char *name; } intel_arch_events_map[] __initconst = { diff --git a/arch/x86/kernel/microcode_core.c b/arch/x86/kernel/microcode_core.c index 947e4c64b1d8..1649cf899ad6 100644 --- a/arch/x86/kernel/microcode_core.c +++ b/arch/x86/kernel/microcode_core.c @@ -87,6 +87,7 @@ #include #include #include +#include MODULE_DESCRIPTION("Microcode Update Driver"); MODULE_AUTHOR("Tigran Aivazian "); @@ -277,7 +278,6 @@ static int reload_for_cpu(int cpu) struct ucode_cpu_info *uci = ucode_cpu_info + cpu; int err = 0; - mutex_lock(µcode_mutex); if (uci->valid) { enum ucode_state ustate; @@ -288,7 +288,6 @@ static int reload_for_cpu(int cpu) if (ustate == UCODE_ERROR) err = -EINVAL; } - mutex_unlock(µcode_mutex); return err; } @@ -309,6 +308,7 @@ static ssize_t reload_store(struct device *dev, return size; get_online_cpus(); + mutex_lock(µcode_mutex); for_each_online_cpu(cpu) { tmp_ret = reload_for_cpu(cpu); if (tmp_ret != 0) @@ -318,6 +318,9 @@ static ssize_t reload_store(struct device *dev, if (!ret) ret = tmp_ret; } + if (!ret) + perf_check_microcode(); + mutex_unlock(µcode_mutex); put_online_cpus(); if (!ret) @@ -557,7 +560,8 @@ static int __init microcode_init(void) mutex_lock(µcode_mutex); error = subsys_interface_register(&mc_cpu_interface); - + if (!error) + perf_check_microcode(); mutex_unlock(µcode_mutex); put_online_cpus(); -- 2.25.1