Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753434AbZC0JIS (ORCPT ); Fri, 27 Mar 2009 05:08:18 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752064AbZC0JIA (ORCPT ); Fri, 27 Mar 2009 05:08:00 -0400 Received: from mga02.intel.com ([134.134.136.20]:19609 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750846AbZC0JH6 (ORCPT ); Fri, 27 Mar 2009 05:07:58 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.38,431,1233561600"; d="scan'208";a="398011967" Date: Fri, 27 Mar 2009 10:07:48 +0100 From: Markus Metzger To: linux-kernel@vger.kernel.org, mingo@elte.hu, tglx@linutronix.de, hpa@zytor.com Cc: markus.t.metzger@intel.com, markus.t.metzger@gmail.com, roland@redhat.com, eranian@googlemail.com, oleg@redhat.com, juan.villacis@intel.com, ak@linux.jf.intel.com Subject: [patch 6/14] x86, ds: add _noirq variants for ds_ functions Message-ID: <20090327100748.A11268@sedona.ch.intel.com> Mime-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.2.5i Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 32061 Lines: 1176 Add functions to the Debug Store interface that may be called (with some restrictions) with irq's disabled. Undo the GFP_ATOMIC changes from an earlier patch. Memory is allocated using GFP_KERNEL. Split ds_request into _cpu and _task variants. Change all users to use the correct ds_request variant. Allow the non-_noirq variants to be called from different cpus for cpu tracing. Remove the unnecessary lock in the hw-branch-tracer. Use get/put_online_cpus() to synchronize with hotplug cpu events. Signed-off-by: Markus Metzger --- Index: git-tip/arch/x86/include/asm/ds.h =================================================================== --- git-tip.orig/arch/x86/include/asm/ds.h 2009-03-27 07:59:23.000000000 +0100 +++ git-tip/arch/x86/include/asm/ds.h 2009-03-27 08:01:13.000000000 +0100 @@ -15,8 +15,8 @@ * - buffer allocation (memory accounting) * * - * Copyright (C) 2007-2008 Intel Corporation. - * Markus Metzger , 2007-2008 + * Copyright (C) 2007-2009 Intel Corporation. + * Markus Metzger , 2007-2009 */ #ifndef _ASM_X86_DS_H @@ -83,8 +83,10 @@ enum ds_feature { * The interrupt threshold is independent from the overflow callback * to allow users to use their own overflow interrupt handling mechanism. * - * task: the task to request recording for; - * NULL for per-cpu recording on the current cpu + * The function may sleep. + * + * task: the task to request recording for + * cpu: the cpu to request recording for * base: the base pointer for the (non-pageable) buffer; * size: the size of the provided buffer in bytes * ovfl: pointer to a function to be called on buffer overflow; @@ -93,19 +95,28 @@ enum ds_feature { * -1 if no interrupt threshold is requested. * flags: a bit-mask of the above flags */ -extern struct bts_tracer *ds_request_bts(struct task_struct *task, - void *base, size_t size, - bts_ovfl_callback_t ovfl, - size_t th, unsigned int flags); -extern struct pebs_tracer *ds_request_pebs(struct task_struct *task, - void *base, size_t size, - pebs_ovfl_callback_t ovfl, - size_t th, unsigned int flags); +extern struct bts_tracer *ds_request_bts_task(struct task_struct *task, + void *base, size_t size, + bts_ovfl_callback_t ovfl, + size_t th, unsigned int flags); +extern struct bts_tracer *ds_request_bts_cpu(int cpu, void *base, size_t size, + bts_ovfl_callback_t ovfl, + size_t th, unsigned int flags); +extern struct pebs_tracer *ds_request_pebs_task(struct task_struct *task, + void *base, size_t size, + pebs_ovfl_callback_t ovfl, + size_t th, unsigned int flags); +extern struct pebs_tracer *ds_request_pebs_cpu(int cpu, + void *base, size_t size, + pebs_ovfl_callback_t ovfl, + size_t th, unsigned int flags); /* * Release BTS or PEBS resources * Suspend and resume BTS or PEBS tracing * + * Must be called with irq's enabled. + * * tracer: the tracer handle returned from ds_request_~() */ extern void ds_release_bts(struct bts_tracer *tracer); @@ -115,6 +126,31 @@ extern void ds_release_pebs(struct pebs_ extern void ds_suspend_pebs(struct pebs_tracer *tracer); extern void ds_resume_pebs(struct pebs_tracer *tracer); +/* + * Release BTS or PEBS resources + * Suspend and resume BTS or PEBS tracing + * + * Cpu tracers must call this on the traced cpu. + * + * Task tracers must call ds_release_~_noirq() for themselves or ensure + * that tracing is inactive before calling ds_release_~_noirq(). + * + * May be called with irq's disabled. + * + * Returns 0 if successful; + * -EPERM if the cpu tracer does not trace the current cpu. + * -EPERM if the task tracer does not trace itself and tracing has not + * been suspended. + * + * tracer: the tracer handle returned from ds_request_~() + */ +extern int ds_release_bts_noirq(struct bts_tracer *tracer); +extern int ds_suspend_bts_noirq(struct bts_tracer *tracer); +extern int ds_resume_bts_noirq(struct bts_tracer *tracer); +extern int ds_release_pebs_noirq(struct pebs_tracer *tracer); +extern int ds_suspend_pebs_noirq(struct pebs_tracer *tracer); +extern int ds_resume_pebs_noirq(struct pebs_tracer *tracer); + /* * The raw DS buffer state as it is used for BTS and PEBS recording. Index: git-tip/arch/x86/kernel/ds.c =================================================================== --- git-tip.orig/arch/x86/kernel/ds.c 2009-03-27 08:00:41.000000000 +0100 +++ git-tip/arch/x86/kernel/ds.c 2009-03-27 08:04:39.000000000 +0100 @@ -233,68 +233,64 @@ struct ds_context { struct pebs_tracer *pebs_master; /* Use count: */ - unsigned long count; + unsigned long count; /* Pointer to the context pointer field: */ struct ds_context **this; - /* The traced task; NULL for current cpu: */ + /* The traced task; NULL for cpu tracing: */ struct task_struct *task; -}; -static DEFINE_PER_CPU(struct ds_context *, system_context_array); + /* The traced cpu; only valid if task is NULL: */ + int cpu; +}; -#define system_context per_cpu(system_context_array, smp_processor_id()) +static DEFINE_PER_CPU(struct ds_context *, cpu_context); -static inline struct ds_context *ds_get_context(struct task_struct *task) +static struct ds_context *ds_get_context(struct task_struct *task, int cpu) { struct ds_context **p_context = - (task ? &task->thread.ds_ctx : &system_context); + (task ? &task->thread.ds_ctx : &per_cpu(cpu_context, cpu)); struct ds_context *context = NULL; struct ds_context *new_context = NULL; unsigned long irq; - /* - * Chances are small that we already have a context. - * - * Contexts for per-cpu tracing are allocated using - * smp_call_function(). We must not sleep. - */ - new_context = kzalloc(sizeof(*new_context), GFP_ATOMIC); + /* Chances are small that we already have a context. */ + new_context = kzalloc(sizeof(*new_context), GFP_KERNEL); if (!new_context) return NULL; spin_lock_irqsave(&ds_lock, irq); context = *p_context; - if (!context) { + if (likely(!context)) { context = new_context; context->this = p_context; context->task = task; + context->cpu = cpu; context->count = 0; - if (task) - set_tsk_thread_flag(task, TIF_DS_AREA_MSR); - - if (!task || (task == current)) - wrmsrl(MSR_IA32_DS_AREA, (unsigned long)context->ds); - *p_context = context; - } + /* + * We defer the DS_AREA msr initialization until after the + * context ownership has been clarified. + */ + } context->count++; spin_unlock_irqrestore(&ds_lock, irq); + if (context != new_context) kfree(new_context); return context; } -static inline void ds_put_context(struct ds_context *context) +static void ds_put_context(struct ds_context *context) { unsigned long irq; @@ -313,14 +309,45 @@ static inline void ds_put_context(struct if (context->task) clear_tsk_thread_flag(context->task, TIF_DS_AREA_MSR); - if (!context->task || (context->task == current)) - wrmsrl(MSR_IA32_DS_AREA, 0); - + /* + * We leave the (now dangling) pointer to the DS configuration in + * the DS_AREA msr. This is as good or as bad as replacing it with + * NULL - the hardware would crash if we enabled tracing. + * + * This saves us some problems with having to write an msr on a + * different cpu while preventing others from doing the same for the + * next context for that same cpu. + */ spin_unlock_irqrestore(&ds_lock, irq); kfree(context); } +static void ds_install_ds_area(struct ds_context *context) +{ + unsigned long ds; + + ds = (unsigned long)context->ds; + + /* + * There is a race between the bts master and the pebs master. + * + * The thread/cpu access is synchronized via get/put_cpu() for + * task tracing and via wrmsr_on_cpu for cpu tracing. + * + * If bts and pebs are collected for the same task or same cpu, + * the same confiuration is written twice. + */ + if (context->task) { + get_cpu(); + if (context->task == current) + wrmsrl(MSR_IA32_DS_AREA, ds); + set_tsk_thread_flag(context->task, TIF_DS_AREA_MSR); + put_cpu(); + } else + wrmsr_on_cpu(context->cpu, MSR_IA32_DS_AREA, + (u32)((u64)ds), (u32)((u64)ds >> 32)); +} /* * Call the tracer's callback on a buffer overflow. @@ -603,6 +630,7 @@ static void ds_init_ds_trace(struct ds_t * The value for 'no threshold' is -1, which will set the * threshold outside of the buffer, just like we want it. */ + ith *= ds_cfg.sizeof_rec[qual]; trace->ith = (void *)(buffer + size - ith); trace->flags = flags; @@ -611,7 +639,7 @@ static void ds_init_ds_trace(struct ds_t static int ds_request(struct ds_tracer *tracer, struct ds_trace *trace, enum ds_qualifier qual, struct task_struct *task, - void *base, size_t size, size_t th, unsigned int flags) + int cpu, void *base, size_t size, size_t th) { struct ds_context *context; int error; @@ -624,7 +652,7 @@ static int ds_request(struct ds_tracer * if (!base) goto out; - /* We require some space to do alignment adjustments below. */ + /* We need space for alignment adjustments in ds_init_ds_trace(). */ error = -EINVAL; if (size < (DS_ALIGNMENT + ds_cfg.sizeof_rec[qual])) goto out; @@ -641,25 +669,27 @@ static int ds_request(struct ds_tracer * tracer->size = size; error = -ENOMEM; - context = ds_get_context(task); + context = ds_get_context(task, cpu); if (!context) goto out; tracer->context = context; - ds_init_ds_trace(trace, qual, base, size, th, flags); + /* + * Defer any tracer-specific initialization work for the context until + * context ownership has been clarified. + */ error = 0; out: return error; } -struct bts_tracer *ds_request_bts(struct task_struct *task, - void *base, size_t size, - bts_ovfl_callback_t ovfl, size_t th, - unsigned int flags) +static struct bts_tracer *ds_request_bts(struct task_struct *task, int cpu, + void *base, size_t size, + bts_ovfl_callback_t ovfl, size_t th, + unsigned int flags) { struct bts_tracer *tracer; - unsigned long irq; int error; /* Buffer overflow notification is not yet implemented. */ @@ -667,23 +697,21 @@ struct bts_tracer *ds_request_bts(struct if (ovfl) goto out; - /* - * Per-cpu tracing is typically requested using smp_call_function(). - * We must not sleep. - */ error = -ENOMEM; - tracer = kzalloc(sizeof(*tracer), GFP_ATOMIC); + tracer = kzalloc(sizeof(*tracer), GFP_KERNEL); if (!tracer) goto out; tracer->ovfl = ovfl; + /* Do some more error checking and acquire a tracing context. */ error = ds_request(&tracer->ds, &tracer->trace.ds, - ds_bts, task, base, size, th, flags); + ds_bts, task, cpu, base, size, th); if (error < 0) goto out_tracer; - spin_lock_irqsave(&ds_lock, irq); + /* Claim the bts part of the tracing context we acquired above. */ + spin_lock_irq(&ds_lock); error = -EPERM; if (!check_tracer(task)) @@ -695,13 +723,20 @@ struct bts_tracer *ds_request_bts(struct goto out_put_tracer; tracer->ds.context->bts_master = tracer; - spin_unlock_irqrestore(&ds_lock, irq); + spin_unlock_irq(&ds_lock); + /* + * Now that we own the bts part of the context, let's complete the + * initialization for that part. + */ + ds_init_ds_trace(&tracer->trace.ds, ds_bts, base, size, th, flags); + ds_write_config(tracer->ds.context, &tracer->trace.ds, ds_bts); + ds_install_ds_area(tracer->ds.context); tracer->trace.read = bts_read; tracer->trace.write = bts_write; - ds_write_config(tracer->ds.context, &tracer->trace.ds, ds_bts); + /* Start tracing. */ ds_resume_bts(tracer); return tracer; @@ -709,7 +744,7 @@ struct bts_tracer *ds_request_bts(struct out_put_tracer: put_tracer(task); out_unlock: - spin_unlock_irqrestore(&ds_lock, irq); + spin_unlock_irq(&ds_lock); ds_put_context(tracer->ds.context); out_tracer: kfree(tracer); @@ -717,13 +752,27 @@ struct bts_tracer *ds_request_bts(struct return ERR_PTR(error); } -struct pebs_tracer *ds_request_pebs(struct task_struct *task, - void *base, size_t size, - pebs_ovfl_callback_t ovfl, size_t th, - unsigned int flags) +struct bts_tracer *ds_request_bts_task(struct task_struct *task, + void *base, size_t size, + bts_ovfl_callback_t ovfl, + size_t th, unsigned int flags) +{ + return ds_request_bts(task, 0, base, size, ovfl, th, flags); +} + +struct bts_tracer *ds_request_bts_cpu(int cpu, void *base, size_t size, + bts_ovfl_callback_t ovfl, + size_t th, unsigned int flags) +{ + return ds_request_bts(NULL, cpu, base, size, ovfl, th, flags); +} + +static struct pebs_tracer *ds_request_pebs(struct task_struct *task, int cpu, + void *base, size_t size, + pebs_ovfl_callback_t ovfl, size_t th, + unsigned int flags) { struct pebs_tracer *tracer; - unsigned long irq; int error; /* Buffer overflow notification is not yet implemented. */ @@ -741,12 +790,14 @@ struct pebs_tracer *ds_request_pebs(stru goto out; tracer->ovfl = ovfl; + /* Do some more error checking and acquire a tracing context. */ error = ds_request(&tracer->ds, &tracer->trace.ds, - ds_pebs, task, base, size, th, flags); + ds_pebs, task, cpu, base, size, th); if (error < 0) goto out_tracer; - spin_lock_irqsave(&ds_lock, irq); + /* Claim the pebs part of the tracing context we acquired above. */ + spin_lock_irq(&ds_lock); error = -EPERM; if (!check_tracer(task)) @@ -758,9 +809,17 @@ struct pebs_tracer *ds_request_pebs(stru goto out_put_tracer; tracer->ds.context->pebs_master = tracer; - spin_unlock_irqrestore(&ds_lock, irq); + spin_unlock_irq(&ds_lock); + /* + * Now that we own the pebs part of the context, let's complete the + * initialization for that part. + */ + ds_init_ds_trace(&tracer->trace.ds, ds_pebs, base, size, th, flags); ds_write_config(tracer->ds.context, &tracer->trace.ds, ds_pebs); + ds_install_ds_area(tracer->ds.context); + + /* Start tracing. */ ds_resume_pebs(tracer); return tracer; @@ -768,7 +827,7 @@ struct pebs_tracer *ds_request_pebs(stru out_put_tracer: put_tracer(task); out_unlock: - spin_unlock_irqrestore(&ds_lock, irq); + spin_unlock_irq(&ds_lock); ds_put_context(tracer->ds.context); out_tracer: kfree(tracer); @@ -776,59 +835,161 @@ struct pebs_tracer *ds_request_pebs(stru return ERR_PTR(error); } +struct pebs_tracer *ds_request_pebs_task(struct task_struct *task, + void *base, size_t size, + pebs_ovfl_callback_t ovfl, + size_t th, unsigned int flags) +{ + return ds_request_pebs(task, 0, base, size, ovfl, th, flags); +} + +struct pebs_tracer *ds_request_pebs_cpu(int cpu, void *base, size_t size, + pebs_ovfl_callback_t ovfl, + size_t th, unsigned int flags) +{ + return ds_request_pebs(NULL, cpu, base, size, ovfl, th, flags); +} + +static void ds_free_bts(struct bts_tracer *tracer) +{ + WARN_ON_ONCE(tracer->ds.context->bts_master != tracer); + tracer->ds.context->bts_master = NULL; + + put_tracer(tracer->ds.context->task); + ds_put_context(tracer->ds.context); + + kfree(tracer); +} + void ds_release_bts(struct bts_tracer *tracer) { + struct task_struct *task; + if (!tracer) return; - ds_suspend_bts(tracer); + task = tracer->ds.context->task; + ds_suspend_bts(tracer); /* * We must wait for the suspend to take effect before we may * free the tracer and the ds configuration. */ - if (tracer->ds.context->task && - (tracer->ds.context->task != current)) - wait_task_inactive(tracer->ds.context->task, 0); + if (task && (task != current)) + wait_task_inactive(task, 0); + ds_free_bts(tracer); +} - WARN_ON_ONCE(tracer->ds.context->bts_master != tracer); - tracer->ds.context->bts_master = NULL; +int ds_release_bts_noirq(struct bts_tracer *tracer) +{ + struct task_struct *task; + unsigned long irq; + int error; - put_tracer(tracer->ds.context->task); - ds_put_context(tracer->ds.context); + if (!tracer) + return 0; - kfree(tracer); + task = tracer->ds.context->task; + + local_irq_save(irq); + + error = -EPERM; + if (!task && + (tracer->ds.context->cpu != smp_processor_id())) + goto out; + + error = -EPERM; + if (task && (task != current) && + (task->thread.debugctlmsr & BTS_CONTROL)) + goto out; + + ds_suspend_bts_noirq(tracer); + ds_free_bts(tracer); + + error = 0; + out: + local_irq_restore(irq); + return error; +} + +static void update_task_debugctlmsr(struct task_struct *task, + unsigned long debugctlmsr) +{ + task->thread.debugctlmsr = debugctlmsr; + + get_cpu(); + if (task == current) + update_debugctlmsr(debugctlmsr); + + if (task->thread.debugctlmsr) + set_tsk_thread_flag(task, TIF_DEBUGCTLMSR); + else + clear_tsk_thread_flag(task, TIF_DEBUGCTLMSR); + put_cpu(); } void ds_suspend_bts(struct bts_tracer *tracer) { struct task_struct *task; + unsigned long debugctlmsr; + int cpu; if (!tracer) return; task = tracer->ds.context->task; + cpu = tracer->ds.context->cpu; - if (!task || (task == current)) - update_debugctlmsr(get_debugctlmsr() & ~BTS_CONTROL); + WARN_ON(!task && irqs_disabled()); - if (task) { - task->thread.debugctlmsr &= ~BTS_CONTROL; + debugctlmsr = (task ? + task->thread.debugctlmsr : + get_debugctlmsr_on_cpu(cpu)); + debugctlmsr &= ~BTS_CONTROL; - if (!task->thread.debugctlmsr) - clear_tsk_thread_flag(task, TIF_DEBUGCTLMSR); - } + if (task) + update_task_debugctlmsr(task, debugctlmsr); + else + update_debugctlmsr_on_cpu(cpu, debugctlmsr); } -void ds_resume_bts(struct bts_tracer *tracer) +int ds_suspend_bts_noirq(struct bts_tracer *tracer) { struct task_struct *task; - unsigned long control; + unsigned long debugctlmsr, irq; + int cpu, error = 0; if (!tracer) - return; + return 0; task = tracer->ds.context->task; + cpu = tracer->ds.context->cpu; + + local_irq_save(irq); + + error = -EPERM; + if (!task && (cpu != smp_processor_id())) + goto out; + + debugctlmsr = (task ? + task->thread.debugctlmsr : + get_debugctlmsr()); + debugctlmsr &= ~BTS_CONTROL; + + if (task) + update_task_debugctlmsr(task, debugctlmsr); + else + update_debugctlmsr(debugctlmsr); + + error = 0; + out: + local_irq_restore(irq); + return error; +} + +static unsigned long ds_bts_control(struct bts_tracer *tracer) +{ + unsigned long control; control = ds_cfg.ctl[dsf_bts]; if (!(tracer->trace.ds.flags & BTS_KERNEL)) @@ -836,22 +997,70 @@ void ds_resume_bts(struct bts_tracer *tr if (!(tracer->trace.ds.flags & BTS_USER)) control |= ds_cfg.ctl[dsf_bts_user]; - if (task) { - task->thread.debugctlmsr |= control; - set_tsk_thread_flag(task, TIF_DEBUGCTLMSR); - } - - if (!task || (task == current)) - update_debugctlmsr(get_debugctlmsr() | control); + return control; } -void ds_release_pebs(struct pebs_tracer *tracer) +void ds_resume_bts(struct bts_tracer *tracer) { + struct task_struct *task; + unsigned long debugctlmsr; + int cpu; + if (!tracer) return; - ds_suspend_pebs(tracer); + task = tracer->ds.context->task; + cpu = tracer->ds.context->cpu; + + WARN_ON(!task && irqs_disabled()); + debugctlmsr = (task ? + task->thread.debugctlmsr : + get_debugctlmsr_on_cpu(cpu)); + debugctlmsr |= ds_bts_control(tracer); + + if (task) + update_task_debugctlmsr(task, debugctlmsr); + else + update_debugctlmsr_on_cpu(cpu, debugctlmsr); +} + +int ds_resume_bts_noirq(struct bts_tracer *tracer) +{ + struct task_struct *task; + unsigned long debugctlmsr, irq; + int cpu, error = 0; + + if (!tracer) + return 0; + + task = tracer->ds.context->task; + cpu = tracer->ds.context->cpu; + + local_irq_save(irq); + + error = -EPERM; + if (!task && (cpu != smp_processor_id())) + goto out; + + debugctlmsr = (task ? + task->thread.debugctlmsr : + get_debugctlmsr()); + debugctlmsr |= ds_bts_control(tracer); + + if (task) + update_task_debugctlmsr(task, debugctlmsr); + else + update_debugctlmsr(debugctlmsr); + + error = 0; + out: + local_irq_restore(irq); + return error; +} + +static void ds_free_pebs(struct pebs_tracer *tracer) +{ WARN_ON_ONCE(tracer->ds.context->pebs_master != tracer); tracer->ds.context->pebs_master = NULL; @@ -861,16 +1070,46 @@ void ds_release_pebs(struct pebs_tracer kfree(tracer); } +void ds_release_pebs(struct pebs_tracer *tracer) +{ + if (!tracer) + return; + + ds_suspend_pebs(tracer); + ds_free_pebs(tracer); +} + +int ds_release_pebs_noirq(struct pebs_tracer *tracer) +{ + if (!tracer) + return 0; + + ds_suspend_pebs_noirq(tracer); + ds_free_pebs(tracer); + + return 0; +} + void ds_suspend_pebs(struct pebs_tracer *tracer) { } +int ds_suspend_pebs_noirq(struct pebs_tracer *tracer) +{ + return 0; +} + void ds_resume_pebs(struct pebs_tracer *tracer) { } +int ds_resume_pebs_noirq(struct pebs_tracer *tracer) +{ + return 0; +} + const struct bts_trace *ds_read_bts(struct bts_tracer *tracer) { if (!tracer) @@ -979,26 +1218,6 @@ ds_configure(const struct ds_configurati printk(KERN_INFO "[ds] pebs not available\n"); } - if (ds_cfg.sizeof_rec[ds_bts]) { - int error; - - error = ds_selftest_bts(); - if (error) { - WARN(1, "[ds] selftest failed. disabling bts.\n"); - ds_cfg.sizeof_rec[ds_bts] = 0; - } - } - - if (ds_cfg.sizeof_rec[ds_pebs]) { - int error; - - error = ds_selftest_pebs(); - if (error) { - WARN(1, "[ds] selftest failed. disabling pebs.\n"); - ds_cfg.sizeof_rec[ds_pebs] = 0; - } - } - printk(KERN_INFO "[ds] sizes: address: %u bit, ", 8 * ds_cfg.sizeof_ptr_field); printk("bts/pebs record: %u/%u bytes\n", @@ -1093,3 +1312,29 @@ void ds_copy_thread(struct task_struct * void ds_exit_thread(struct task_struct *tsk) { } + +static __init int ds_selftest(void) +{ + if (ds_cfg.sizeof_rec[ds_bts]) { + int error; + + error = ds_selftest_bts(); + if (error) { + WARN(1, "[ds] selftest failed. disabling bts.\n"); + ds_cfg.sizeof_rec[ds_bts] = 0; + } + } + + if (ds_cfg.sizeof_rec[ds_pebs]) { + int error; + + error = ds_selftest_pebs(); + if (error) { + WARN(1, "[ds] selftest failed. disabling pebs.\n"); + ds_cfg.sizeof_rec[ds_pebs] = 0; + } + } + + return 0; +} +device_initcall(ds_selftest); Index: git-tip/kernel/trace/trace_hw_branches.c =================================================================== --- git-tip.orig/kernel/trace/trace_hw_branches.c 2009-03-27 07:59:23.000000000 +0100 +++ git-tip/kernel/trace/trace_hw_branches.c 2009-03-27 08:01:13.000000000 +0100 @@ -4,7 +4,6 @@ * Copyright (C) 2008-2009 Intel Corporation. * Markus Metzger , 2008-2009 */ -#include #include #include #include @@ -21,168 +20,108 @@ #define BTS_BUFFER_SIZE (1 << 13) -/* - * The tracer lock protects the below per-cpu tracer array. - * It needs to be held to: - * - start tracing on all cpus - * - stop tracing on all cpus - * - start tracing on a single hotplug cpu - * - stop tracing on a single hotplug cpu - * - read the trace from all cpus - * - read the trace from a single cpu - */ -static DEFINE_SPINLOCK(bts_tracer_lock); static DEFINE_PER_CPU(struct bts_tracer *, tracer); static DEFINE_PER_CPU(unsigned char[BTS_BUFFER_SIZE], buffer); #define this_tracer per_cpu(tracer, smp_processor_id()) -#define this_buffer per_cpu(buffer, smp_processor_id()) static int trace_hw_branches_enabled __read_mostly; static int trace_hw_branches_suspended __read_mostly; static struct trace_array *hw_branch_trace __read_mostly; -/* - * Initialize the tracer for the current cpu. - * The argument is ignored. - * - * pre: bts_tracer_lock must be locked. - */ -static void bts_trace_init_cpu(void *arg) +static void bts_trace_init_cpu(int cpu) { - if (this_tracer) - ds_release_bts(this_tracer); + might_sleep(); - this_tracer = ds_request_bts(NULL, this_buffer, BTS_BUFFER_SIZE, - NULL, (size_t)-1, BTS_KERNEL); - if (IS_ERR(this_tracer)) { - this_tracer = NULL; - return; - } + per_cpu(tracer, cpu) = + ds_request_bts_cpu(cpu, per_cpu(buffer, cpu), BTS_BUFFER_SIZE, + NULL, (size_t)-1, BTS_KERNEL); + + if (IS_ERR(per_cpu(tracer, cpu))) + per_cpu(tracer, cpu) = NULL; } static int bts_trace_init(struct trace_array *tr) { - int cpu, avail; - - spin_lock(&bts_tracer_lock); + int cpu; hw_branch_trace = tr; + trace_hw_branches_enabled = 0; - on_each_cpu(bts_trace_init_cpu, NULL, 1); + get_online_cpus(); + for_each_online_cpu(cpu) { + bts_trace_init_cpu(cpu); - /* Check on how many cpus we could enable tracing */ - avail = 0; - for_each_online_cpu(cpu) if (per_cpu(tracer, cpu)) - avail++; - - trace_hw_branches_enabled = (avail ? 1 : 0); + trace_hw_branches_enabled = 1; + } trace_hw_branches_suspended = 0; - - spin_unlock(&bts_tracer_lock); - + put_online_cpus(); /* If we could not enable tracing on a single cpu, we fail. */ - return avail ? 0 : -EOPNOTSUPP; -} - -/* - * Release the tracer for the current cpu. - * The argument is ignored. - * - * pre: bts_tracer_lock must be locked. - */ -static void bts_trace_release_cpu(void *arg) -{ - if (this_tracer) { - ds_release_bts(this_tracer); - this_tracer = NULL; - } + return trace_hw_branches_enabled ? 0 : -EOPNOTSUPP; } static void bts_trace_reset(struct trace_array *tr) { - spin_lock(&bts_tracer_lock); + int cpu; - on_each_cpu(bts_trace_release_cpu, NULL, 1); + get_online_cpus(); + for_each_online_cpu(cpu) { + ds_release_bts(per_cpu(tracer, cpu)); + per_cpu(tracer, cpu) = NULL; + } trace_hw_branches_enabled = 0; trace_hw_branches_suspended = 0; - - spin_unlock(&bts_tracer_lock); -} - -/* - * Resume tracing on the current cpu. - * The argument is ignored. - * - * pre: bts_tracer_lock must be locked. - */ -static void bts_trace_resume_cpu(void *arg) -{ - if (this_tracer) - ds_resume_bts(this_tracer); + put_online_cpus(); } static void bts_trace_start(struct trace_array *tr) { - spin_lock(&bts_tracer_lock); + int cpu; - on_each_cpu(bts_trace_resume_cpu, NULL, 1); + get_online_cpus(); + for_each_online_cpu(cpu) + if (per_cpu(tracer, cpu)) + ds_resume_bts(per_cpu(tracer, cpu)); trace_hw_branches_suspended = 0; - - spin_unlock(&bts_tracer_lock); -} - -/* - * Suspend tracing on the current cpu. - * The argument is ignored. - * - * pre: bts_tracer_lock must be locked. - */ -static void bts_trace_suspend_cpu(void *arg) -{ - if (this_tracer) - ds_suspend_bts(this_tracer); + put_online_cpus(); } static void bts_trace_stop(struct trace_array *tr) { - spin_lock(&bts_tracer_lock); + int cpu; - on_each_cpu(bts_trace_suspend_cpu, NULL, 1); + get_online_cpus(); + for_each_online_cpu(cpu) + if (per_cpu(tracer, cpu)) + ds_suspend_bts(per_cpu(tracer, cpu)); trace_hw_branches_suspended = 1; - - spin_unlock(&bts_tracer_lock); + put_online_cpus(); } static int __cpuinit bts_hotcpu_handler(struct notifier_block *nfb, unsigned long action, void *hcpu) { - unsigned int cpu = (unsigned long)hcpu; - - spin_lock(&bts_tracer_lock); - - if (!trace_hw_branches_enabled) - goto out; + int cpu = (long)hcpu; switch (action) { case CPU_ONLINE: case CPU_DOWN_FAILED: - smp_call_function_single(cpu, bts_trace_init_cpu, NULL, 1); + if (trace_hw_branches_enabled) { + bts_trace_init_cpu(cpu); - if (trace_hw_branches_suspended) - smp_call_function_single(cpu, bts_trace_suspend_cpu, - NULL, 1); + if (trace_hw_branches_suspended) + ds_suspend_bts(per_cpu(tracer, cpu)); + } break; + case CPU_DOWN_PREPARE: - smp_call_function_single(cpu, bts_trace_release_cpu, NULL, 1); - break; + ds_release_bts(per_cpu(tracer, cpu)); + per_cpu(tracer, cpu) = NULL; } - out: - spin_unlock(&bts_tracer_lock); return NOTIFY_DONE; } @@ -275,6 +214,7 @@ static void trace_bts_at(const struct bt * Collect the trace on the current cpu and write it into the ftrace buffer. * * pre: bts_tracer_lock must be locked + * pre: tracing must be suspended on the current cpu */ static void trace_bts_cpu(void *arg) { @@ -291,10 +231,9 @@ static void trace_bts_cpu(void *arg) if (unlikely(!this_tracer)) return; - ds_suspend_bts(this_tracer); trace = ds_read_bts(this_tracer); if (!trace) - goto out; + return; for (at = trace->ds.top; (void *)at < trace->ds.end; at += trace->ds.size) @@ -303,18 +242,25 @@ static void trace_bts_cpu(void *arg) for (at = trace->ds.begin; (void *)at < trace->ds.top; at += trace->ds.size) trace_bts_at(trace, at); - -out: - ds_resume_bts(this_tracer); } static void trace_bts_prepare(struct trace_iterator *iter) { - spin_lock(&bts_tracer_lock); + int cpu; + get_online_cpus(); + for_each_online_cpu(cpu) + ds_suspend_bts(per_cpu(tracer, cpu)); + /* + * We need to collect the trace on the respective cpu since ftrace + * implicitly adds the record for the current cpu. + * Once that is more flexible, we could collect the data from any cpu. + */ on_each_cpu(trace_bts_cpu, iter->tr, 1); - spin_unlock(&bts_tracer_lock); + for_each_online_cpu(cpu) + ds_resume_bts(per_cpu(tracer, cpu)); + put_online_cpus(); } static void trace_bts_close(struct trace_iterator *iter) @@ -324,12 +270,11 @@ static void trace_bts_close(struct trace void trace_hw_branch_oops(void) { - spin_lock(&bts_tracer_lock); - - if (trace_hw_branches_enabled) + if (this_tracer) { + ds_suspend_bts_noirq(this_tracer); trace_bts_cpu(hw_branch_trace); - - spin_unlock(&bts_tracer_lock); + ds_resume_bts_noirq(this_tracer); + } } struct tracer bts_tracer __read_mostly = Index: git-tip/arch/x86/kernel/ptrace.c =================================================================== --- git-tip.orig/arch/x86/kernel/ptrace.c 2009-03-27 08:00:39.000000000 +0100 +++ git-tip/arch/x86/kernel/ptrace.c 2009-03-27 08:01:13.000000000 +0100 @@ -708,9 +708,9 @@ static int ptrace_bts_config(struct task if (cfg.flags & PTRACE_BTS_O_SCHED) flags |= BTS_TIMESTAMPS; - child->bts = ds_request_bts(child, child->bts_buffer, child->bts_size, - /* ovfl = */ NULL, /* th = */ (size_t)-1, - flags); + child->bts = ds_request_bts_task(child, child->bts_buffer, + child->bts_size, + NULL, (size_t)-1, flags); if (IS_ERR(child->bts)) { int error = PTR_ERR(child->bts); Index: git-tip/arch/x86/kernel/ds_selftest.c =================================================================== --- git-tip.orig/arch/x86/kernel/ds_selftest.c 2009-03-27 07:59:23.000000000 +0100 +++ git-tip/arch/x86/kernel/ds_selftest.c 2009-03-27 08:01:13.000000000 +0100 @@ -10,6 +10,7 @@ #include #include +#include #include @@ -129,8 +130,9 @@ int ds_selftest_bts(void) printk(KERN_INFO "[ds] bts selftest..."); - tracer = ds_request_bts(NULL, buffer, DS_SELFTEST_BUFFER_SIZE, - NULL, (size_t)-1, BTS_KERNEL); + tracer = ds_request_bts_cpu(smp_processor_id(), buffer, + DS_SELFTEST_BUFFER_SIZE, NULL, (size_t)-1, + BTS_KERNEL); if (IS_ERR(tracer)) { error = PTR_ERR(tracer); tracer = NULL; --------------------------------------------------------------------- Intel GmbH Dornacher Strasse 1 85622 Feldkirchen/Muenchen Germany Sitz der Gesellschaft: Feldkirchen bei Muenchen Geschaeftsfuehrer: Douglas Lusk, Peter Gleissner, Hannes Schwaderer Registergericht: Muenchen HRB 47456 Ust.-IdNr. 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