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author | Ingo Molnar <mingo@kernel.org> | 2016-04-28 08:35:17 (GMT) |
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committer | Ingo Molnar <mingo@kernel.org> | 2016-04-28 08:35:17 (GMT) |
commit | 0b20e59cef927b030c2e626f40fc4965bacec847 (patch) | |
tree | c090a7a4e2c20065eb5825debff1a724a7775b8a | |
parent | a8944c5bf86dc6c153a71f2a386738c0d3f5ff9c (diff) | |
parent | cf3beb7c90a8efa16a06b26634cddddc92bb819c (diff) | |
download | linux-0b20e59cef927b030c2e626f40fc4965bacec847.tar.xz |
Merge branch 'perf/urgent' into perf/core, to resolve conflict
Conflicts:
arch/x86/events/intel/pt.c
Signed-off-by: Ingo Molnar <mingo@kernel.org>
-rw-r--r-- | arch/x86/events/amd/core.c | 2 | ||||
-rw-r--r-- | arch/x86/events/intel/lbr.c | 6 | ||||
-rw-r--r-- | arch/x86/events/intel/pt.c | 75 | ||||
-rw-r--r-- | arch/x86/events/intel/pt.h | 3 | ||||
-rw-r--r-- | arch/x86/include/asm/perf_event.h | 4 | ||||
-rw-r--r-- | arch/x86/kvm/vmx.c | 4 | ||||
-rw-r--r-- | kernel/events/core.c | 52 |
7 files changed, 116 insertions, 30 deletions
diff --git a/arch/x86/events/amd/core.c b/arch/x86/events/amd/core.c index 86a9bec..bd3e842 100644 --- a/arch/x86/events/amd/core.c +++ b/arch/x86/events/amd/core.c @@ -115,7 +115,7 @@ static __initconst const u64 amd_hw_cache_event_ids /* * AMD Performance Monitor K7 and later. */ -static const u64 amd_perfmon_event_map[] = +static const u64 amd_perfmon_event_map[PERF_COUNT_HW_MAX] = { [PERF_COUNT_HW_CPU_CYCLES] = 0x0076, [PERF_COUNT_HW_INSTRUCTIONS] = 0x00c0, diff --git a/arch/x86/events/intel/lbr.c b/arch/x86/events/intel/lbr.c index 317e29e..9e2b40c 100644 --- a/arch/x86/events/intel/lbr.c +++ b/arch/x86/events/intel/lbr.c @@ -64,7 +64,7 @@ static enum { #define LBR_PLM (LBR_KERNEL | LBR_USER) -#define LBR_SEL_MASK 0x1ff /* valid bits in LBR_SELECT */ +#define LBR_SEL_MASK 0x3ff /* valid bits in LBR_SELECT */ #define LBR_NOT_SUPP -1 /* LBR filter not supported */ #define LBR_IGN 0 /* ignored */ @@ -621,8 +621,10 @@ static int intel_pmu_setup_hw_lbr_filter(struct perf_event *event) * The first 9 bits (LBR_SEL_MASK) in LBR_SELECT operate * in suppress mode. So LBR_SELECT should be set to * (~mask & LBR_SEL_MASK) | (mask & ~LBR_SEL_MASK) + * But the 10th bit LBR_CALL_STACK does not operate + * in suppress mode. */ - reg->config = mask ^ x86_pmu.lbr_sel_mask; + reg->config = mask ^ (x86_pmu.lbr_sel_mask & ~LBR_CALL_STACK); if ((br_type & PERF_SAMPLE_BRANCH_NO_CYCLES) && (br_type & PERF_SAMPLE_BRANCH_NO_FLAGS) && diff --git a/arch/x86/events/intel/pt.c b/arch/x86/events/intel/pt.c index 1aefd43..05ef87d 100644 --- a/arch/x86/events/intel/pt.c +++ b/arch/x86/events/intel/pt.c @@ -136,9 +136,21 @@ static int __init pt_pmu_hw_init(void) struct dev_ext_attribute *de_attrs; struct attribute **attrs; size_t size; + u64 reg; int ret; long i; + if (boot_cpu_has(X86_FEATURE_VMX)) { + /* + * Intel SDM, 36.5 "Tracing post-VMXON" says that + * "IA32_VMX_MISC[bit 14]" being 1 means PT can trace + * post-VMXON. + */ + rdmsrl(MSR_IA32_VMX_MISC, reg); + if (reg & BIT(14)) + pt_pmu.vmx = true; + } + attrs = NULL; for (i = 0; i < PT_CPUID_LEAVES; i++) { @@ -269,20 +281,23 @@ static void pt_config(struct perf_event *event) reg |= (event->attr.config & PT_CONFIG_MASK); + event->hw.config = reg; wrmsrl(MSR_IA32_RTIT_CTL, reg); } -static void pt_config_start(bool start) +static void pt_config_stop(struct perf_event *event) { - u64 ctl; + u64 ctl = READ_ONCE(event->hw.config); + + /* may be already stopped by a PMI */ + if (!(ctl & RTIT_CTL_TRACEEN)) + return; - rdmsrl(MSR_IA32_RTIT_CTL, ctl); - if (start) - ctl |= RTIT_CTL_TRACEEN; - else - ctl &= ~RTIT_CTL_TRACEEN; + ctl &= ~RTIT_CTL_TRACEEN; wrmsrl(MSR_IA32_RTIT_CTL, ctl); + WRITE_ONCE(event->hw.config, ctl); + /* * A wrmsr that disables trace generation serializes other PT * registers and causes all data packets to be written to memory, @@ -291,8 +306,7 @@ static void pt_config_start(bool start) * The below WMB, separating data store and aux_head store matches * the consumer's RMB that separates aux_head load and data load. */ - if (!start) - wmb(); + wmb(); } static void pt_config_buffer(void *buf, unsigned int topa_idx, @@ -922,11 +936,17 @@ void intel_pt_interrupt(void) if (!ACCESS_ONCE(pt->handle_nmi)) return; - pt_config_start(false); + /* + * If VMX is on and PT does not support it, don't touch anything. + */ + if (READ_ONCE(pt->vmx_on)) + return; if (!event) return; + pt_config_stop(event); + buf = perf_get_aux(&pt->handle); if (!buf) return; @@ -963,6 +983,35 @@ void intel_pt_interrupt(void) } } +void intel_pt_handle_vmx(int on) +{ + struct pt *pt = this_cpu_ptr(&pt_ctx); + struct perf_event *event; + unsigned long flags; + + /* PT plays nice with VMX, do nothing */ + if (pt_pmu.vmx) + return; + + /* + * VMXON will clear RTIT_CTL.TraceEn; we need to make + * sure to not try to set it while VMX is on. Disable + * interrupts to avoid racing with pmu callbacks; + * concurrent PMI should be handled fine. + */ + local_irq_save(flags); + WRITE_ONCE(pt->vmx_on, on); + + if (on) { + /* prevent pt_config_stop() from writing RTIT_CTL */ + event = pt->handle.event; + if (event) + event->hw.config = 0; + } + local_irq_restore(flags); +} +EXPORT_SYMBOL_GPL(intel_pt_handle_vmx); + /* * PMU callbacks */ @@ -973,6 +1022,9 @@ static void pt_event_start(struct perf_event *event, int mode) struct pt *pt = this_cpu_ptr(&pt_ctx); struct pt_buffer *buf; + if (READ_ONCE(pt->vmx_on)) + return; + buf = perf_aux_output_begin(&pt->handle, event); if (!buf) goto fail_stop; @@ -1007,7 +1059,8 @@ static void pt_event_stop(struct perf_event *event, int mode) * see comment in intel_pt_interrupt(). */ ACCESS_ONCE(pt->handle_nmi) = 0; - pt_config_start(false); + + pt_config_stop(event); if (event->hw.state == PERF_HES_STOPPED) return; diff --git a/arch/x86/events/intel/pt.h b/arch/x86/events/intel/pt.h index 336878a..3abb5f5 100644 --- a/arch/x86/events/intel/pt.h +++ b/arch/x86/events/intel/pt.h @@ -65,6 +65,7 @@ enum pt_capabilities { struct pt_pmu { struct pmu pmu; u32 caps[PT_CPUID_REGS_NUM * PT_CPUID_LEAVES]; + bool vmx; }; /** @@ -107,10 +108,12 @@ struct pt_buffer { * struct pt - per-cpu pt context * @handle: perf output handle * @handle_nmi: do handle PT PMI on this cpu, there's an active event + * @vmx_on: 1 if VMX is ON on this cpu */ struct pt { struct perf_output_handle handle; int handle_nmi; + int vmx_on; }; #endif /* __INTEL_PT_H__ */ diff --git a/arch/x86/include/asm/perf_event.h b/arch/x86/include/asm/perf_event.h index 5a2ed3e..f353061 100644 --- a/arch/x86/include/asm/perf_event.h +++ b/arch/x86/include/asm/perf_event.h @@ -285,6 +285,10 @@ static inline void perf_events_lapic_init(void) { } static inline void perf_check_microcode(void) { } #endif +#ifdef CONFIG_CPU_SUP_INTEL + extern void intel_pt_handle_vmx(int on); +#endif + #if defined(CONFIG_PERF_EVENTS) && defined(CONFIG_CPU_SUP_AMD) extern void amd_pmu_enable_virt(void); extern void amd_pmu_disable_virt(void); diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index ee1c8a9..133679d 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -3103,6 +3103,8 @@ static __init int vmx_disabled_by_bios(void) static void kvm_cpu_vmxon(u64 addr) { + intel_pt_handle_vmx(1); + asm volatile (ASM_VMX_VMXON_RAX : : "a"(&addr), "m"(addr) : "memory", "cc"); @@ -3172,6 +3174,8 @@ static void vmclear_local_loaded_vmcss(void) static void kvm_cpu_vmxoff(void) { asm volatile (__ex(ASM_VMX_VMXOFF) : : : "cc"); + + intel_pt_handle_vmx(0); } static void hardware_disable(void) diff --git a/kernel/events/core.c b/kernel/events/core.c index eabeb2a..9de459a 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -1106,6 +1106,7 @@ static void put_ctx(struct perf_event_context *ctx) * function. * * Lock order: + * cred_guard_mutex * task_struct::perf_event_mutex * perf_event_context::mutex * perf_event::child_mutex; @@ -3449,7 +3450,6 @@ static struct task_struct * find_lively_task_by_vpid(pid_t vpid) { struct task_struct *task; - int err; rcu_read_lock(); if (!vpid) @@ -3463,16 +3463,7 @@ find_lively_task_by_vpid(pid_t vpid) if (!task) return ERR_PTR(-ESRCH); - /* Reuse ptrace permission checks for now. */ - err = -EACCES; - if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS)) - goto errout; - return task; -errout: - put_task_struct(task); - return ERR_PTR(err); - } /* @@ -8592,6 +8583,24 @@ SYSCALL_DEFINE5(perf_event_open, get_online_cpus(); + if (task) { + err = mutex_lock_interruptible(&task->signal->cred_guard_mutex); + if (err) + goto err_cpus; + + /* + * Reuse ptrace permission checks for now. + * + * We must hold cred_guard_mutex across this and any potential + * perf_install_in_context() call for this new event to + * serialize against exec() altering our credentials (and the + * perf_event_exit_task() that could imply). + */ + err = -EACCES; + if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS)) + goto err_cred; + } + if (flags & PERF_FLAG_PID_CGROUP) cgroup_fd = pid; @@ -8599,7 +8608,7 @@ SYSCALL_DEFINE5(perf_event_open, NULL, NULL, cgroup_fd); if (IS_ERR(event)) { err = PTR_ERR(event); - goto err_cpus; + goto err_cred; } if (is_sampling_event(event)) { @@ -8658,11 +8667,6 @@ SYSCALL_DEFINE5(perf_event_open, goto err_context; } - if (task) { - put_task_struct(task); - task = NULL; - } - /* * Look up the group leader (we will attach this event to it): */ @@ -8760,6 +8764,11 @@ SYSCALL_DEFINE5(perf_event_open, WARN_ON_ONCE(ctx->parent_ctx); + /* + * This is the point on no return; we cannot fail hereafter. This is + * where we start modifying current state. + */ + if (move_group) { /* * See perf_event_ctx_lock() for comments on the details @@ -8831,6 +8840,11 @@ SYSCALL_DEFINE5(perf_event_open, mutex_unlock(&gctx->mutex); mutex_unlock(&ctx->mutex); + if (task) { + mutex_unlock(&task->signal->cred_guard_mutex); + put_task_struct(task); + } + put_online_cpus(); mutex_lock(¤t->perf_event_mutex); @@ -8863,6 +8877,9 @@ err_alloc: */ if (!event_file) free_event(event); +err_cred: + if (task) + mutex_unlock(&task->signal->cred_guard_mutex); err_cpus: put_online_cpus(); err_task: @@ -9147,6 +9164,9 @@ static void perf_event_exit_task_context(struct task_struct *child, int ctxn) /* * When a child task exits, feed back event values to parent events. + * + * Can be called with cred_guard_mutex held when called from + * install_exec_creds(). */ void perf_event_exit_task(struct task_struct *child) { |