From c9fc3f778a6a215ace14ee556067c73982b6d40f Mon Sep 17 00:00:00 2001 From: Borislav Petkov Date: Thu, 21 Jun 2012 14:07:16 +0200 Subject: x86, microcode: Sanitize per-cpu microcode reloading interface Microcode reloading in a per-core manner is a very bad idea for both major x86 vendors. And the thing is, we have such interface with which we can end up with different microcode versions applied on different cores of an otherwise homogeneous wrt (family,model,stepping) system. So turn off the possibility of doing that per core and allow it only system-wide. This is a minimal fix which we'd like to see in stable too thus the more-or-less arbitrary decision to allow system-wide reloading only on the BSP: $ echo 1 > /sys/devices/system/cpu/cpu0/microcode/reload ... and disable the interface on the other cores: $ echo 1 > /sys/devices/system/cpu/cpu23/microcode/reload -bash: echo: write error: Invalid argument Also, allowing the reload only from one CPU (the BSP in that case) doesn't allow the reload procedure to degenerate into an O(n^2) deal when triggering reloads from all /sys/devices/system/cpu/cpuX/microcode/reload sysfs nodes simultaneously. A more generic fix will follow. Cc: Henrique de Moraes Holschuh Cc: Peter Zijlstra Signed-off-by: Borislav Petkov Link: http://lkml.kernel.org/r/1340280437-7718-2-git-send-email-bp@amd64.org Signed-off-by: H. Peter Anvin Cc: --- arch/x86/kernel/microcode_core.c | 26 +++++++++++++++++++------- 1 file changed, 19 insertions(+), 7 deletions(-) (limited to 'arch/x86/kernel/microcode_core.c') diff --git a/arch/x86/kernel/microcode_core.c b/arch/x86/kernel/microcode_core.c index fbdfc6917180..24b852b61be3 100644 --- a/arch/x86/kernel/microcode_core.c +++ b/arch/x86/kernel/microcode_core.c @@ -298,19 +298,31 @@ static ssize_t reload_store(struct device *dev, const char *buf, size_t size) { unsigned long val; - int cpu = dev->id; - ssize_t ret = 0; + int cpu; + ssize_t ret = 0, tmp_ret; + + /* allow reload only from the BSP */ + if (boot_cpu_data.cpu_index != dev->id) + return -EINVAL; ret = kstrtoul(buf, 0, &val); if (ret) return ret; - if (val == 1) { - get_online_cpus(); - if (cpu_online(cpu)) - ret = reload_for_cpu(cpu); - put_online_cpus(); + if (val != 1) + return size; + + get_online_cpus(); + for_each_online_cpu(cpu) { + tmp_ret = reload_for_cpu(cpu); + if (tmp_ret != 0) + pr_warn("Error reloading microcode on CPU %d\n", cpu); + + /* save retval of the first encountered reload error */ + if (!ret) + ret = tmp_ret; } + put_online_cpus(); if (!ret) ret = size; -- cgit From 3d8986bc7f309483ee09c7a02888bab09072c19b Mon Sep 17 00:00:00 2001 From: Borislav Petkov Date: Thu, 21 Jun 2012 14:07:17 +0200 Subject: x86, microcode: Make reload interface per system The reload interface should be per-system so that a full system ucode reload happens (on each core) when doing echo 1 > /sys/devices/system/cpu/microcode/reload Move it to the cpu subsys directory instead of it being per-cpu. Cc: Henrique de Moraes Holschuh Cc: Peter Zijlstra Signed-off-by: Borislav Petkov Link: http://lkml.kernel.org/r/1340280437-7718-3-git-send-email-bp@amd64.org Signed-off-by: H. Peter Anvin --- arch/x86/kernel/microcode_core.c | 36 ++++++++++++++++++++++++++++-------- 1 file changed, 28 insertions(+), 8 deletions(-) (limited to 'arch/x86/kernel/microcode_core.c') diff --git a/arch/x86/kernel/microcode_core.c b/arch/x86/kernel/microcode_core.c index 24b852b61be3..947e4c64b1d8 100644 --- a/arch/x86/kernel/microcode_core.c +++ b/arch/x86/kernel/microcode_core.c @@ -301,10 +301,6 @@ static ssize_t reload_store(struct device *dev, int cpu; ssize_t ret = 0, tmp_ret; - /* allow reload only from the BSP */ - if (boot_cpu_data.cpu_index != dev->id) - return -EINVAL; - ret = kstrtoul(buf, 0, &val); if (ret) return ret; @@ -351,7 +347,6 @@ static DEVICE_ATTR(version, 0400, version_show, NULL); static DEVICE_ATTR(processor_flags, 0400, pf_show, NULL); static struct attribute *mc_default_attrs[] = { - &dev_attr_reload.attr, &dev_attr_version.attr, &dev_attr_processor_flags.attr, NULL @@ -528,6 +523,16 @@ static const struct x86_cpu_id microcode_id[] = { MODULE_DEVICE_TABLE(x86cpu, microcode_id); #endif +static struct attribute *cpu_root_microcode_attrs[] = { + &dev_attr_reload.attr, + NULL +}; + +static struct attribute_group cpu_root_microcode_group = { + .name = "microcode", + .attrs = cpu_root_microcode_attrs, +}; + static int __init microcode_init(void) { struct cpuinfo_x86 *c = &cpu_data(0); @@ -559,9 +564,17 @@ static int __init microcode_init(void) if (error) goto out_pdev; + error = sysfs_create_group(&cpu_subsys.dev_root->kobj, + &cpu_root_microcode_group); + + if (error) { + pr_err("Error creating microcode group!\n"); + goto out_driver; + } + error = microcode_dev_init(); if (error) - goto out_driver; + goto out_ucode_group; register_syscore_ops(&mc_syscore_ops); register_hotcpu_notifier(&mc_cpu_notifier); @@ -571,7 +584,11 @@ static int __init microcode_init(void) return 0; -out_driver: + out_ucode_group: + sysfs_remove_group(&cpu_subsys.dev_root->kobj, + &cpu_root_microcode_group); + + out_driver: get_online_cpus(); mutex_lock(µcode_mutex); @@ -580,7 +597,7 @@ out_driver: mutex_unlock(µcode_mutex); put_online_cpus(); -out_pdev: + out_pdev: platform_device_unregister(microcode_pdev); return error; @@ -596,6 +613,9 @@ static void __exit microcode_exit(void) unregister_hotcpu_notifier(&mc_cpu_notifier); unregister_syscore_ops(&mc_syscore_ops); + sysfs_remove_group(&cpu_subsys.dev_root->kobj, + &cpu_root_microcode_group); + get_online_cpus(); mutex_lock(µcode_mutex); -- cgit From c93dc84cbe32435be3ffa2fbde355eff94955c32 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 8 Jun 2012 14:50:50 +0200 Subject: 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(-) (limited to 'arch/x86/kernel/microcode_core.c') 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(); -- cgit