/* * ring buffer based function tracer * * Copyright (C) 2007-2008 Steven Rostedt * Copyright (C) 2008 Ingo Molnar * * Originally taken from the RT patch by: * Arnaldo Carvalho de Melo * * Based on code from the latency_tracer, that is: * Copyright (C) 2004-2006 Ingo Molnar * Copyright (C) 2004 William Lee Irwin III */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "trace.h" #include "trace_output.h" #define TRACE_BUFFER_FLAGS (RB_FL_OVERWRITE) unsigned long __read_mostly tracing_max_latency; unsigned long __read_mostly tracing_thresh; /* * We need to change this state when a selftest is running. * A selftest will lurk into the ring-buffer to count the * entries inserted during the selftest although some concurrent * insertions into the ring-buffer such as ftrace_printk could occurred * at the same time, giving false positive or negative results. */ static bool __read_mostly tracing_selftest_running; /* * If a tracer is running, we do not want to run SELFTEST. */ static bool __read_mostly tracing_selftest_disabled; /* For tracers that don't implement custom flags */ static struct tracer_opt dummy_tracer_opt[] = { { } }; static struct tracer_flags dummy_tracer_flags = { .val = 0, .opts = dummy_tracer_opt }; static int dummy_set_flag(u32 old_flags, u32 bit, int set) { return 0; } /* * Kill all tracing for good (never come back). * It is initialized to 1 but will turn to zero if the initialization * of the tracer is successful. But that is the only place that sets * this back to zero. */ int tracing_disabled = 1; static DEFINE_PER_CPU(local_t, ftrace_cpu_disabled); static inline void ftrace_disable_cpu(void) { preempt_disable(); local_inc(&__get_cpu_var(ftrace_cpu_disabled)); } static inline void ftrace_enable_cpu(void) { local_dec(&__get_cpu_var(ftrace_cpu_disabled)); preempt_enable(); } static cpumask_var_t __read_mostly tracing_buffer_mask; #define for_each_tracing_cpu(cpu) \ for_each_cpu(cpu, tracing_buffer_mask) /* * ftrace_dump_on_oops - variable to dump ftrace buffer on oops * * If there is an oops (or kernel panic) and the ftrace_dump_on_oops * is set, then ftrace_dump is called. This will output the contents * of the ftrace buffers to the console. This is very useful for * capturing traces that lead to crashes and outputing it to a * serial console. * * It is default off, but you can enable it with either specifying * "ftrace_dump_on_oops" in the kernel command line, or setting * /proc/sys/kernel/ftrace_dump_on_oops to true. */ int ftrace_dump_on_oops; static int tracing_set_tracer(const char *buf); #define BOOTUP_TRACER_SIZE 100 static char bootup_tracer_buf[BOOTUP_TRACER_SIZE] __initdata; static char *default_bootup_tracer; static int __init set_ftrace(char *str) { strncpy(bootup_tracer_buf, str, BOOTUP_TRACER_SIZE); default_bootup_tracer = bootup_tracer_buf; return 1; } __setup("ftrace=", set_ftrace); static int __init set_ftrace_dump_on_oops(char *str) { ftrace_dump_on_oops = 1; return 1; } __setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops); long ns2usecs(cycle_t nsec) { nsec += 500; do_div(nsec, 1000); return nsec; } cycle_t ftrace_now(int cpu) { u64 ts = ring_buffer_time_stamp(cpu); ring_buffer_normalize_time_stamp(cpu, &ts); return ts; } /* * The global_trace is the descriptor that holds the tracing * buffers for the live tracing. For each CPU, it contains * a link list of pages that will store trace entries. The * page descriptor of the pages in the memory is used to hold * the link list by linking the lru item in the page descriptor * to each of the pages in the buffer per CPU. * * For each active CPU there is a data field that holds the * pages for the buffer for that CPU. Each CPU has the same number * of pages allocated for its buffer. */ static struct trace_array global_trace; static DEFINE_PER_CPU(struct trace_array_cpu, global_trace_cpu); /* * The max_tr is used to snapshot the global_trace when a maximum * latency is reached. Some tracers will use this to store a maximum * trace while it continues examining live traces. * * The buffers for the max_tr are set up the same as the global_trace. * When a snapshot is taken, the link list of the max_tr is swapped * with the link list of the global_trace and the buffers are reset for * the global_trace so the tracing can continue. */ static struct trace_array max_tr; static DEFINE_PER_CPU(struct trace_array_cpu, max_data); /* tracer_enabled is used to toggle activation of a tracer */ static int tracer_enabled = 1; /** * tracing_is_enabled - return tracer_enabled status * * This function is used by other tracers to know the status * of the tracer_enabled flag. Tracers may use this function * to know if it should enable their features when starting * up. See irqsoff tracer for an example (start_irqsoff_tracer). */ int tracing_is_enabled(void) { return tracer_enabled; } /* * trace_buf_size is the size in bytes that is allocated * for a buffer. Note, the number of bytes is always rounded * to page size. * * This number is purposely set to a low number of 16384. * If the dump on oops happens, it will be much appreciated * to not have to wait for all that output. Anyway this can be * boot time and run time configurable. */ #define TRACE_BUF_SIZE_DEFAULT 1441792UL /* 16384 * 88 (sizeof(entry)) */ static unsigned long trace_buf_size = TRACE_BUF_SIZE_DEFAULT; /* trace_types holds a link list of available tracers. */ static struct tracer *trace_types __read_mostly; /* current_trace points to the tracer that is currently active */ static struct tracer *current_trace __read_mostly; /* * max_tracer_type_len is used to simplify the allocating of * buffers to read userspace tracer names. We keep track of * the longest tracer name registered. */ static int max_tracer_type_len; /* * trace_types_lock is used to protect the trace_types list. * This lock is also used to keep user access serialized. * Accesses from userspace will grab this lock while userspace * activities happen inside the kernel. */ static DEFINE_MUTEX(trace_types_lock); /* trace_wait is a waitqueue for tasks blocked on trace_poll */ static DECLARE_WAIT_QUEUE_HEAD(trace_wait); /* trace_flags holds trace_options default values */ unsigned long trace_flags = TRACE_ITER_PRINT_PARENT | TRACE_ITER_PRINTK | TRACE_ITER_ANNOTATE; /** * trace_wake_up - wake up tasks waiting for trace input * * Simply wakes up any task that is blocked on the trace_wait * queue. These is used with trace_poll for tasks polling the trace. */ void trace_wake_up(void) { /* * The runqueue_is_locked() can fail, but this is the best we * have for now: */ if (!(trace_flags & TRACE_ITER_BLOCK) && !runqueue_is_locked()) wake_up(&trace_wait); } static int __init set_buf_size(char *str) { unsigned long buf_size; int ret; if (!str) return 0; ret = strict_strtoul(str, 0, &buf_size); /* nr_entries can not be zero */ if (ret < 0 || buf_size == 0) return 0; trace_buf_size = buf_size; return 1; } __setup("trace_buf_size=", set_buf_size); unsigned long nsecs_to_usecs(unsigned long nsecs) { return nsecs / 1000; } /* These must match the bit postions in trace_iterator_flags */ static const char *trace_options[] = { "print-parent", "sym-offset", "sym-addr", "verbose", "raw", "hex", "bin", "block", "stacktrace", "sched-tree", "ftrace_printk", "ftrace_preempt", "branch", "annotate", "userstacktrace", "sym-userobj", "printk-msg-only", NULL }; /* * ftrace_max_lock is used to protect the swapping of buffers * when taking a max snapshot. The buffers themselves are * protected by per_cpu spinlocks. But the action of the swap * needs its own lock. * * This is defined as a raw_spinlock_t in order to help * with performance when lockdep debugging is enabled. */ static raw_spinlock_t ftrace_max_lock = (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED; /* * Copy the new maximum trace into the separate maximum-trace * structure. (this way the maximum trace is permanently saved, * for later retrieval via /debugfs/tracing/latency_trace) */ static void __update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu) { struct trace_array_cpu *data = tr->data[cpu]; max_tr.cpu = cpu; max_tr.time_start = data->preempt_timestamp; data = max_tr.data[cpu]; data->saved_latency = tracing_max_latency; memcpy(data->comm, tsk->comm, TASK_COMM_LEN); data->pid = tsk->pid; data->uid = task_uid(tsk); data->nice = tsk->static_prio - 20 - MAX_RT_PRIO; data->policy = tsk->policy; data->rt_priority = tsk->rt_priority; /* record this tasks comm */ tracing_record_cmdline(current); } static void trace_seq_reset(struct trace_seq *s) { s->len = 0; s->readpos = 0; } ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf, size_t cnt) { int len; int ret; if (s->len <= s->readpos) return -EBUSY; len = s->len - s->readpos; if (cnt > len) cnt = len; ret = copy_to_user(ubuf, s->buffer + s->readpos, cnt); if (ret) return -EFAULT; s->readpos += len; return cnt; } static void trace_print_seq(struct seq_file *m, struct trace_seq *s) { int len = s->len >= PAGE_SIZE ? PAGE_SIZE - 1 : s->len; s->buffer[len] = 0; seq_puts(m, s->buffer); trace_seq_reset(s); } /** * update_max_tr - snapshot all trace buffers from global_trace to max_tr * @tr: tracer * @tsk: the task with the latency * @cpu: The cpu that initiated the trace. * * Flip the buffers between the @tr and the max_tr and record information * about which task was the cause of this latency. */ void update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu) { struct ring_buffer *buf = tr->buffer; WARN_ON_ONCE(!irqs_disabled()); __raw_spin_lock(&ftrace_max_lock); tr->buffer = max_tr.buffer; max_tr.buffer = buf; ftrace_disable_cpu(); ring_buffer_reset(tr->buffer); ftrace_enable_cpu(); __update_max_tr(tr, tsk, cpu); __raw_spin_unlock(&ftrace_max_lock); } /** * update_max_tr_single - only copy one trace over, and reset the rest * @tr - tracer * @tsk - task with the latency * @cpu - the cpu of the buffer to copy. * * Flip the trace of a single CPU buffer between the @tr and the max_tr. */ void update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu) { int ret; WARN_ON_ONCE(!irqs_disabled()); __raw_spin_lock(&ftrace_max_lock); ftrace_disable_cpu(); ring_buffer_reset(max_tr.buffer); ret = ring_buffer_swap_cpu(max_tr.buffer, tr->buffer, cpu); ftrace_enable_cpu(); WARN_ON_ONCE(ret && ret != -EAGAIN); __update_max_tr(tr, tsk, cpu); __raw_spin_unlock(&ftrace_max_lock); } /** * register_tracer - register a tracer with the ftrace system. * @type - the plugin for the tracer * * Register a new plugin tracer. */ int register_tracer(struct tracer *type) { struct tracer *t; int len; int ret = 0; if (!type->name) { pr_info("Tracer must have a name\n"); return -1; } /* * When this gets called we hold the BKL which means that * preemption is disabled. Various trace selftests however * need to disable and enable preemption for successful tests. * So we drop the BKL here and grab it after the tests again. */ unlock_kernel(); mutex_lock(&trace_types_lock); tracing_selftest_running = true; for (t = trace_types; t; t = t->next) { if (strcmp(type->name, t->name) == 0) { /* already found */ pr_info("Trace %s already registered\n", type->name); ret = -1; goto out; } } if (!type->set_flag) type->set_flag = &dummy_set_flag; if (!type->flags) type->flags = &dummy_tracer_flags; else if (!type->flags->opts) type->flags->opts = dummy_tracer_opt; #ifdef CONFIG_FTRACE_STARTUP_TEST if (type->selftest && !tracing_selftest_disabled) { struct tracer *saved_tracer = current_trace; struct trace_array *tr = &global_trace; int i; /* * Run a selftest on this tracer. * Here we reset the trace buffer, and set the current * tracer to be this tracer. The tracer can then run some * internal tracing to verify that everything is in order. * If we fail, we do not register this tracer. */ for_each_tracing_cpu(i) tracing_reset(tr, i); current_trace = type; /* the test is responsible for initializing and enabling */ pr_info("Testing tracer %s: ", type->name); ret = type->selftest(type, tr); /* the test is responsible for resetting too */ current_trace = saved_tracer; if (ret) { printk(KERN_CONT "FAILED!\n"); goto out; } /* Only reset on passing, to avoid touching corrupted buffers */ for_each_tracing_cpu(i) tracing_reset(tr, i); printk(KERN_CONT "PASSED\n"); } #endif type->next = trace_types; trace_types = type; len = strlen(type->name); if (len > max_tracer_type_len) max_tracer_type_len = len; out: tracing_selftest_running = false; mutex_unlock(&trace_types_lock); if (!ret && default_bootup_tracer) { if (!strncmp(default_bootup_tracer, type->name, BOOTUP_TRACER_SIZE)) { printk(KERN_INFO "Starting tracer '%s'\n", type->name); /* Do we want this tracer to start on bootup? */ tracing_set_tracer(type->name); default_bootup_tracer = NULL; /* disable other selftests, since this will break it. */ tracing_selftest_disabled = 1; #ifdef CONFIG_FTRACE_STARTUP_TEST printk(KERN_INFO "Disabling FTRACE selftests due" " to running tracer '%s'\n", type->name); #endif } } lock_kernel(); return ret; } void unregister_tracer(struct tracer *type) { struct tracer **t; int len; mutex_lock(&trace_types_lock); for (t = &trace_types; *t; t = &(*t)->next) { if (*t == type) goto found; } pr_info("Trace %s not registered\n", type->name); goto out; found: *t = (*t)->next; if (strlen(type->name) != max_tracer_type_len) goto out; max_tracer_type_len = 0; for (t = &trace_types; *t; t = &(*t)->next) { len = strlen((*t)->name); if (len > max_tracer_type_len) max_tracer_type_len = len; } out: mutex_unlock(&trace_types_lock); } void tracing_reset(struct trace_array *tr, int cpu) { ftrace_disable_cpu(); ring_buffer_reset_cpu(tr->buffer, cpu); ftrace_enable_cpu(); } void tracing_reset_online_cpus(struct trace_array *tr) { int cpu; tr->time_start = ftrace_now(tr->cpu); for_each_online_cpu(cpu) tracing_reset(tr, cpu); } #define SAVED_CMDLINES 128 static unsigned map_pid_to_cmdline[PID_MAX_DEFAULT+1]; static unsigned map_cmdline_to_pid[SAVED_CMDLINES]; static char saved_cmdlines[SAVED_CMDLINES][TASK_COMM_LEN]; static int cmdline_idx; static DEFINE_SPINLOCK(trace_cmdline_lock); /* temporary disable recording */ atomic_t trace_record_cmdline_disabled __read_mostly; static void trace_init_cmdlines(void) { memset(&map_pid_to_cmdline, -1, sizeof(map_pid_to_cmdline)); memset(&map_cmdline_to_pid, -1, sizeof(map_cmdline_to_pid)); cmdline_idx = 0; } static int trace_stop_count; static DEFINE_SPINLOCK(tracing_start_lock); /** * ftrace_off_permanent - disable all ftrace code permanently * * This should only be called when a serious anomally has * been detected. This will turn off the function tracing, * ring buffers, and other tracing utilites. It takes no * locks and can be called from any context. */ void ftrace_off_permanent(void) { tracing_disabled = 1; ftrace_stop(); tracing_off_permanent(); } /** * tracing_start - quick start of the tracer * * If tracing is enabled but was stopped by tracing_stop, * this will start the tracer back up. */ void tracing_start(void) { struct ring_buffer *buffer; unsigned long flags; if (tracing_disabled) return; spin_lock_irqsave(&tracing_start_lock, flags); if (--trace_stop_count) { if (trace_stop_count < 0) { /* Someone screwed up their debugging */ WARN_ON_ONCE(1); trace_stop_count = 0; } goto out; } buffer = global_trace.buffer; if (buffer) ring_buffer_record_enable(buffer); buffer = max_tr.buffer; if (buffer) ring_buffer_record_enable(buffer); ftrace_start(); out: spin_unlock_irqrestore(&tracing_start_lock, flags); } /** * tracing_stop - quick stop of the tracer * * Light weight way to stop tracing. Use in conjunction with * tracing_start. */ void tracing_stop(void) { struct ring_buffer *buffer; unsigned long flags; ftrace_stop(); spin_lock_irqsave(&tracing_start_lock, flags); if (trace_stop_count++) goto out; buffer = global_trace.buffer; if (buffer) ring_buffer_record_disable(buffer); buffer = max_tr.buffer; if (buffer) ring_buffer_record_disable(buffer); out: spin_unlock_irqrestore(&tracing_start_lock, flags); } void trace_stop_cmdline_recording(void); static void trace_save_cmdline(struct task_struct *tsk) { unsigned map; unsigned idx; if (!tsk->pid || unlikely(tsk->pid > PID_MAX_DEFAULT)) return; /* * It's not the end of the world if we don't get * the lock, but we also don't want to spin * nor do we want to disable interrupts, * so if we miss here, then better luck next time. */ if (!spin_trylock(&trace_cmdline_lock)) return; idx = map_pid_to_cmdline[tsk->pid]; if (idx >= SAVED_CMDLINES) { idx = (cmdline_idx + 1) % SAVED_CMDLINES; map = map_cmdline_to_pid[idx]; if (map <= PID_MAX_DEFAULT) map_pid_to_cmdline[map] = (unsigned)-1; map_pid_to_cmdline[tsk->pid] = idx; cmdline_idx = idx; } memcpy(&saved_cmdlines[idx], tsk->comm, TASK_COMM_LEN); spin_unlock(&trace_cmdline_lock); } char *trace_find_cmdline(int pid) { char *cmdline = "<...>"; unsigned map; if (!pid) return ""; if (pid > PID_MAX_DEFAULT) goto out; map = map_pid_to_cmdline[pid]; if (map >= SAVED_CMDLINES) goto out; cmdline = saved_cmdlines[map]; out: return cmdline; } void tracing_record_cmdline(struct task_struct *tsk) { if (atomic_read(&trace_record_cmdline_disabled)) return; trace_save_cmdline(tsk); } void tracing_generic_entry_update(struct trace_entry *entry, unsigned long flags, int pc) { struct task_struct *tsk = current; entry->preempt_count = pc & 0xff; entry->pid = (tsk) ? tsk->pid : 0; entry->tgid = (tsk) ? tsk->tgid : 0; entry->flags = #ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT (irqs_disabled_flags(flags) ? TRACE_FLAG_IRQS_OFF : 0) | #else TRACE_FLAG_IRQS_NOSUPPORT | #endif ((pc & HARDIRQ_MASK) ? TRACE_FLAG_HARDIRQ : 0) | ((pc & SOFTIRQ_MASK) ? TRACE_FLAG_SOFTIRQ : 0) | (need_resched() ? TRACE_FLAG_NEED_RESCHED : 0); } void trace_function(struct trace_array *tr, struct trace_array_cpu *data, unsigned long ip, unsigned long parent_ip, unsigned long flags, int pc) { struct ring_buffer_event *event; struct ftrace_entry *entry; unsigned long irq_flags; /* If we are reading the ring buffer, don't trace */ if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled)))) return; event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry), &irq_flags); if (!event) return; entry = ring_buffer_event_data(event); tracing_generic_entry_update(&entry->ent, flags, pc); entry->ent.type = TRACE_FN; entry->ip = ip; entry->parent_ip = parent_ip; ring_buffer_unlock_commit(tr->buffer, event, irq_flags); } #ifdef CONFIG_FUNCTION_GRAPH_TRACER static void __trace_graph_entry(struct trace_array *tr, struct trace_array_cpu *data, struct ftrace_graph_ent *trace, unsigned long flags, int pc) { struct ring_buffer_event *event; struct ftrace_graph_ent_entry *entry; unsigned long irq_flags; if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled)))) return; event = ring_buffer_lock_reserve(global_trace.buffer, sizeof(*entry), &irq_flags); if (!event) return; entry = ring_buffer_event_data(event); tracing_generic_entry_update(&entry->ent, flags, pc); entry->ent.type = TRACE_GRAPH_ENT; entry->graph_ent = *trace; ring_buffer_unlock_commit(global_trace.buffer, event, irq_flags); } static void __trace_graph_return(struct trace_array *tr, struct trace_array_cpu *data, struct ftrace_graph_ret *trace, unsigned long flags, int pc) { struct ring_buffer_event *event; struct ftrace_graph_ret_entry *entry; unsigned long irq_flags; if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled)))) return; event = ring_buffer_lock_reserve(global_trace.buffer, sizeof(*entry), &irq_flags); if (!event) return; entry = ring_buffer_event_data(event); tracing_generic_entry_update(&entry->ent, flags, pc); entry->ent.type = TRACE_GRAPH_RET; entry->ret = *trace; ring_buffer_unlock_commit(global_trace.buffer, event, irq_flags); } #endif void ftrace(struct trace_array *tr, struct trace_array_cpu *data, unsigned long ip, unsigned long parent_ip, unsigned long flags, int pc) { if (likely(!atomic_read(&data->disabled))) trace_function(tr, data, ip, parent_ip, flags, pc); } static void __ftrace_trace_stack(struct trace_array *tr, struct trace_array_cpu *data, unsigned long flags, int skip, int pc) { #ifdef CONFIG_STACKTRACE struct ring_buffer_event *event; struct stack_entry *entry; struct stack_trace trace; unsigned long irq_flags; event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry), &irq_flags); if (!event) return; entry = ring_buffer_event_data(event); tracing_generic_entry_update(&entry->ent, flags, pc); entry->ent.type = TRACE_STACK; memset(&entry->caller, 0, sizeof(entry->caller)); trace.nr_entries = 0; trace.max_entries = FTRACE_STACK_ENTRIES; trace.skip = skip; trace.entries = entry->caller; save_stack_trace(&trace); ring_buffer_unlock_commit(tr->buffer, event, irq_flags); #endif } static void ftrace_trace_stack(struct trace_array *tr, struct trace_array_cpu *data, unsigned long flags, int skip, int pc) { if (!(trace_flags & TRACE_ITER_STACKTRACE)) return; __ftrace_trace_stack(tr, data, flags, skip, pc); } void __trace_stack(struct trace_array *tr, struct trace_array_cpu *data, unsigned long flags, int skip, int pc) { __ftrace_trace_stack(tr, data, flags, skip, pc); } static void ftrace_trace_userstack(struct trace_array *tr, struct trace_array_cpu *data, unsigned long flags, int pc) { #ifdef CONFIG_STACKTRACE struct ring_buffer_event *event; struct userstack_entry *entry; struct stack_trace trace; unsigned long irq_flags; if (!(trace_flags & TRACE_ITER_USERSTACKTRACE)) return; event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry), &irq_flags); if (!event) return; entry = ring_buffer_event_data(event); tracing_generic_entry_update(&entry->ent, flags, pc); entry->ent.type = TRACE_USER_STACK; memset(&entry->caller, 0, sizeof(entry->caller)); trace.nr_entries = 0; trace.max_entries = FTRACE_STACK_ENTRIES; trace.skip = 0; trace.entries = entry->caller; save_stack_trace_user(&trace); ring_buffer_unlock_commit(tr->buffer, event, irq_flags); #endif } void __trace_userstack(struct trace_array *tr, struct trace_array_cpu *data, unsigned long flags) { ftrace_trace_userstack(tr, data, flags, preempt_count()); } static void ftrace_trace_special(void *__tr, void *__data, unsigned long arg1, unsigned long arg2, unsigned long arg3, int pc) { struct ring_buffer_event *event; struct trace_array_cpu *data = __data; struct trace_array *tr = __tr; struct special_entry *entry; unsigned long irq_flags; event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry), &irq_flags); if (!event) return; entry = ring_buffer_event_data(event); tracing_generic_entry_update(&entry->ent, 0, pc); entry->ent.type = TRACE_SPECIAL; entry->arg1 = arg1; entry->arg2 = arg2; entry->arg3 = arg3; ring_buffer_unlock_commit(tr->buffer, event, irq_flags); ftrace_trace_stack(tr, data, irq_flags, 4, pc); ftrace_trace_userstack(tr, data, irq_flags, pc); trace_wake_up(); } void __trace_special(void *__tr, void *__data, unsigned long arg1, unsigned long arg2, unsigned long arg3) { ftrace_trace_special(__tr, __data, arg1, arg2, arg3, preempt_count()); } void tracing_sched_switch_trace(struct trace_array *tr, struct trace_array_cpu *data, struct task_struct *prev, struct task_struct *next, unsigned long flags, int pc) { struct ring_buffer_event *event; struct ctx_switch_entry *entry; unsigned long irq_flags; event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry), &irq_flags); if (!event) return; entry = ring_buffer_event_data(event); tracing_generic_entry_update(&entry->ent, flags, pc); entry->ent.type = TRACE_CTX; entry->prev_pid = prev->pid; entry->prev_prio = prev->prio; entry->prev_state = prev->state; entry->next_pid = next->pid; entry->next_prio = next->prio; entry->next_state = next->state; entry->next_cpu = task_cpu(next); ring_buffer_unlock_commit(tr->buffer, event, irq_flags); ftrace_trace_stack(tr, data, flags, 5, pc); ftrace_trace_userstack(tr, data, flags, pc); } void tracing_sched_wakeup_trace(struct trace_array *tr, struct trace_array_cpu *data, struct task_struct *wakee, struct task_struct *curr, unsigned long flags, int pc) { struct ring_buffer_event *event; struct ctx_switch_entry *entry; unsigned long irq_flags; event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry), &irq_flags); if (!event) return; entry = ring_buffer_event_data(event); tracing_generic_entry_update(&entry->ent, flags, pc); entry->ent.type = TRACE_WAKE; entry->prev_pid = curr->pid; entry->prev_prio = curr->prio; entry->prev_state = curr->state; entry->next_pid = wakee->pid; entry->next_prio = wakee->prio; entry->next_state = wakee->state; entry->next_cpu = task_cpu(wakee); ring_buffer_unlock_commit(tr->buffer, event, irq_flags); ftrace_trace_stack(tr, data, flags, 6, pc); ftrace_trace_userstack(tr, data, flags, pc); trace_wake_up(); } void ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3) { struct trace_array *tr = &global_trace; struct trace_array_cpu *data; unsigned long flags; int cpu; int pc; if (tracing_disabled) return; pc = preempt_count(); local_irq_save(flags); cpu = raw_smp_processor_id(); data = tr->data[cpu]; if (likely(atomic_inc_return(&data->disabled) == 1)) ftrace_trace_special(tr, data, arg1, arg2, arg3, pc); atomic_dec(&data->disabled); local_irq_restore(flags); } #ifdef CONFIG_FUNCTION_GRAPH_TRACER int trace_graph_entry(struct ftrace_graph_ent *trace) { struct trace_array *tr = &global_trace; struct trace_array_cpu *data; unsigned long flags; long disabled; int cpu; int pc; if (!ftrace_trace_task(current)) return 0; if (!ftrace_graph_addr(trace->func)) return 0; local_irq_save(flags); cpu = raw_smp_processor_id(); data = tr->data[cpu]; disabled = atomic_inc_return(&data->disabled); if (likely(disabled == 1)) { pc = preempt_count(); __trace_graph_entry(tr, data, trace, flags, pc); } /* Only do the atomic if it is not already set */ if (!test_tsk_trace_graph(current)) set_tsk_trace_graph(current); atomic_dec(&data->disabled); local_irq_restore(flags); return 1; } void trace_graph_return(struct ftrace_graph_ret *trace) { struct trace_array *tr = &global_trace; struct trace_array_cpu *data; unsigned long flags; long disabled; int cpu; int pc; local_irq_save(flags); cpu = raw_smp_processor_id(); data = tr->data[cpu]; disabled = atomic_inc_return(&data->disabled); if (likely(disabled == 1)) { pc = preempt_count(); __trace_graph_return(tr, data, trace, flags, pc); } if (!trace->depth) clear_tsk_trace_graph(current); atomic_dec(&data->disabled); local_irq_restore(flags); } #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ enum trace_file_type { TRACE_FILE_LAT_FMT = 1, TRACE_FILE_ANNOTATE = 2, }; static void trace_iterator_increment(struct trace_iterator *iter) { /* Don't allow ftrace to trace into the ring buffers */ ftrace_disable_cpu(); iter->idx++; if (iter->buffer_iter[iter->cpu]) ring_buffer_read(iter->buffer_iter[iter->cpu], NULL); ftrace_enable_cpu(); } static struct trace_entry * peek_next_entry(struct trace_iterator *iter, int cpu, u64 *ts) { struct ring_buffer_event *event; struct ring_buffer_iter *buf_iter = iter->buffer_iter[cpu]; /* Don't allow ftrace to trace into the ring buffers */ ftrace_disable_cpu(); if (buf_iter) event = ring_buffer_iter_peek(buf_iter, ts); else event = ring_buffer_peek(iter->tr->buffer, cpu, ts); ftrace_enable_cpu(); return event ? ring_buffer_event_data(event) : NULL; } static struct trace_entry * __find_next_entry(struct trace_iterator *iter, int *ent_cpu, u64 *ent_ts) { struct ring_buffer *buffer = iter->tr->buffer; struct trace_entry *ent, *next = NULL; u64 next_ts = 0, ts; int next_cpu = -1; int cpu; for_each_tracing_cpu(cpu) { if (ring_buffer_empty_cpu(buffer, cpu)) continue; ent = peek_next_entry(iter, cpu, &ts); /* * Pick the entry with the smallest timestamp: */ if (ent && (!next || ts < next_ts)) { next = ent; next_cpu = cpu; next_ts = ts; } } if (ent_cpu) *ent_cpu = next_cpu; if (ent_ts) *ent_ts = next_ts; return next; } /* Find the next real entry, without updating the iterator itself */ static struct trace_entry * find_next_entry(struct trace_iterator *iter, int *ent_cpu, u64 *ent_ts) { return __find_next_entry(iter, ent_cpu, ent_ts); } /* Find the next real entry, and increment the iterator to the next entry */ static void *find_next_entry_inc(struct trace_iterator *iter) { iter->ent = __find_next_entry(iter, &iter->cpu, &iter->ts); if (iter->ent) trace_iterator_increment(iter); return iter->ent ? iter : NULL; } static void trace_consume(struct trace_iterator *iter) { /* Don't allow ftrace to trace into the ring buffers */ ftrace_disable_cpu(); ring_buffer_consume(iter->tr->buffer, iter->cpu, &iter->ts); ftrace_enable_cpu(); } static void *s_next(struct seq_file *m, void *v, loff_t *pos) { struct trace_iterator *iter = m->private; int i = (int)*pos; void *ent; (*pos)++; /* can't go backwards */ if (iter->idx > i) return NULL; if (iter->idx < 0) ent = find_next_entry_inc(iter); else ent = iter; while (ent && iter->idx < i) ent = find_next_entry_inc(iter); iter->pos = *pos; return ent; } static void *s_start(struct seq_file *m, loff_t *pos) { struct trace_iterator *iter = m->private; void *p = NULL; loff_t l = 0; int cpu; mutex_lock(&trace_types_lock); if (!current_trace || current_trace != iter->trace) { mutex_unlock(&trace_types_lock); return NULL; } atomic_inc(&trace_record_cmdline_disabled); if (*pos != iter->pos) { iter->ent = NULL; iter->cpu = 0; iter->idx = -1; ftrace_disable_cpu(); for_each_tracing_cpu(cpu) { ring_buffer_iter_reset(iter->buffer_iter[cpu]); } ftrace_enable_cpu(); for (p = iter; p && l < *pos; p = s_next(m, p, &l)) ; } else { l = *pos - 1; p = s_next(m, p, &l); } return p; } static void s_stop(struct seq_file *m, void *p) { atomic_dec(&trace_record_cmdline_disabled); mutex_unlock(&trace_types_lock); } static void print_lat_help_header(struct seq_file *m) { seq_puts(m, "# _------=> CPU# \n"); seq_puts(m, "# / _-----=> irqs-off \n"); seq_puts(m, "# | / _----=> need-resched \n"); seq_puts(m, "# || / _---=> hardirq/softirq \n"); seq_puts(m, "# ||| / _--=> preempt-depth \n"); seq_puts(m, "# |||| / \n"); seq_puts(m, "# ||||| delay \n"); seq_puts(m, "# cmd pid ||||| time | caller \n"); seq_puts(m, "# \\ / ||||| \\ | / \n"); } static void print_func_help_header(struct seq_file *m) { seq_puts(m, "# TASK-PID CPU# TIMESTAMP FUNCTION\n"); seq_puts(m, "# | | | | |\n"); } static void print_trace_header(struct seq_file *m, struct trace_iterator *iter) { unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK); struct trace_array *tr = iter->tr; struct trace_array_cpu *data = tr->data[tr->cpu]; struct tracer *type = current_trace; unsigned long total; unsigned long entries; const char *name = "preemption"; if (type) name = type->name; entries = ring_buffer_entries(iter->tr->buffer); total = entries + ring_buffer_overruns(iter->tr->buffer); seq_printf(m, "%s latency trace v1.1.5 on %s\n", name, UTS_RELEASE); seq_puts(m, "-----------------------------------" "---------------------------------\n"); seq_printf(m, " latency: %lu us, #%lu/%lu, CPU#%d |" " (M:%s VP:%d, KP:%d, SP:%d HP:%d", nsecs_to_usecs(data->saved_latency), entries, total, tr->cpu, #if defined(CONFIG_PREEMPT_NONE) "server", #elif defined(CONFIG_PREEMPT_VOLUNTARY) "desktop", #elif defined(CONFIG_PREEMPT) "preempt", #else "unknown", #endif /* These are reserved for later use */ 0, 0, 0, 0); #ifdef CONFIG_SMP seq_printf(m, " #P:%d)\n", num_online_cpus()); #else seq_puts(m, ")\n"); #endif seq_puts(m, " -----------------\n"); seq_printf(m, " | task: %.16s-%d " "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n", data->comm, data->pid, data->uid, data->nice, data->policy, data->rt_priority); seq_puts(m, " -----------------\n"); if (data->critical_start) { seq_puts(m, " => started at: "); seq_print_ip_sym(&iter->seq, data->critical_start, sym_flags); trace_print_seq(m, &iter->seq); seq_puts(m, "\n => ended at: "); seq_print_ip_sym(&iter->seq, data->critical_end, sym_flags); trace_print_seq(m, &iter->seq); seq_puts(m, "\n"); } seq_puts(m, "\n"); } static void lat_print_generic(struct trace_seq *s, struct trace_entry *entry, int cpu) { int hardirq, softirq; char *comm; comm = trace_find_cmdline(entry->pid); trace_seq_printf(s, "%8.8s-%-5d ", comm, entry->pid); trace_seq_printf(s, "%3d", cpu); trace_seq_printf(s, "%c%c", (entry->flags & TRACE_FLAG_IRQS_OFF) ? 'd' : (entry->flags & TRACE_FLAG_IRQS_NOSUPPORT) ? 'X' : '.', ((entry->flags & TRACE_FLAG_NEED_RESCHED) ? 'N' : '.')); hardirq = entry->flags & TRACE_FLAG_HARDIRQ; softirq = entry->flags & TRACE_FLAG_SOFTIRQ; if (hardirq && softirq) { trace_seq_putc(s, 'H'); } else { if (hardirq) { trace_seq_putc(s, 'h'); } else { if (softirq) trace_seq_putc(s, 's'); else trace_seq_putc(s, '.'); } } if (entry->preempt_count) trace_seq_printf(s, "%x", entry->preempt_count); else trace_seq_puts(s, "."); } unsigned long preempt_mark_thresh = 100; static void lat_print_timestamp(struct trace_seq *s, u64 abs_usecs, unsigned long rel_usecs) { trace_seq_printf(s, " %4lldus", abs_usecs); if (rel_usecs > preempt_mark_thresh) trace_seq_puts(s, "!: "); else if (rel_usecs > 1) trace_seq_puts(s, "+: "); else trace_seq_puts(s, " : "); } static void test_cpu_buff_start(struct trace_iterator *iter) { struct trace_seq *s = &iter->seq; if (!(trace_flags & TRACE_ITER_ANNOTATE)) return; if (!(iter->iter_flags & TRACE_FILE_ANNOTATE)) return; if (cpumask_test_cpu(iter->cpu, iter->started)) return; cpumask_set_cpu(iter->cpu, iter->started); trace_seq_printf(s, "##### CPU %u buffer started ####\n", iter->cpu); } static enum print_line_t print_lat_fmt(struct trace_iterator *iter, unsigned int trace_idx, int cpu) { struct trace_seq *s = &iter->seq; unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK); struct trace_entry *next_entry; struct trace_event *event; unsigned long verbose = (trace_flags & TRACE_ITER_VERBOSE); struct trace_entry *entry = iter->ent; unsigned long abs_usecs; unsigned long rel_usecs; u64 next_ts; char *comm; int ret; test_cpu_buff_start(iter); next_entry = find_next_entry(iter, NULL, &next_ts); if (!next_entry) next_ts = iter->ts; rel_usecs = ns2usecs(next_ts - iter->ts); abs_usecs = ns2usecs(iter->ts - iter->tr->time_start); if (verbose) { comm = trace_find_cmdline(entry->pid); trace_seq_printf(s, "%16s %5d %3d %d %08x %08x [%08lx]" " %ld.%03ldms (+%ld.%03ldms): ", comm, entry->pid, cpu, entry->flags, entry->preempt_count, trace_idx, ns2usecs(iter->ts), abs_usecs/1000, abs_usecs % 1000, rel_usecs/1000, rel_usecs % 1000); } else { lat_print_generic(s, entry, cpu); lat_print_timestamp(s, abs_usecs, rel_usecs); } event = ftrace_find_event(entry->type); if (event && event->latency_trace) { ret = event->latency_trace(s, entry, sym_flags); if (ret) return ret; return TRACE_TYPE_HANDLED; } trace_seq_printf(s, "Unknown type %d\n", entry->type); return TRACE_TYPE_HANDLED; } static enum print_line_t print_trace_fmt(struct trace_iterator *iter) { struct trace_seq *s = &iter->seq; unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK); struct trace_entry *entry; struct trace_event *event; unsigned long usec_rem; unsigned long long t; unsigned long secs; char *comm; int ret; entry = iter->ent; test_cpu_buff_start(iter); comm = trace_find_cmdline(iter->ent->pid); t = ns2usecs(iter->ts); usec_rem = do_div(t, 1000000ULL); secs = (unsigned long)t; ret = trace_seq_printf(s, "%16s-%-5d ", comm, entry->pid); if (!ret) return TRACE_TYPE_PARTIAL_LINE; ret = trace_seq_printf(s, "[%03d] ", iter->cpu); if (!ret) return TRACE_TYPE_PARTIAL_LINE; ret = trace_seq_printf(s, "%5lu.%06lu: ", secs, usec_rem); if (!ret) return TRACE_TYPE_PARTIAL_LINE; event = ftrace_find_event(entry->type); if (event && event->trace) { ret = event->trace(s, entry, sym_flags); if (ret) return ret; return TRACE_TYPE_HANDLED; } ret = trace_seq_printf(s, "Unknown type %d\n", entry->type); if (!ret) return TRACE_TYPE_PARTIAL_LINE; return TRACE_TYPE_HANDLED; } static enum print_line_t print_raw_fmt(struct trace_iterator *iter) { struct trace_seq *s = &iter->seq; struct trace_entry *entry; struct trace_event *event; int ret; entry = iter->ent; ret = trace_seq_printf(s, "%d %d %llu ", entry->pid, iter->cpu, iter->ts); if (!ret) return TRACE_TYPE_PARTIAL_LINE; event = ftrace_find_event(entry->type); if (event && event->raw) { ret = event->raw(s, entry, 0); if (ret) return ret; return TRACE_TYPE_HANDLED; } ret = trace_seq_printf(s, "%d ?\n", entry->type); if (!ret) return TRACE_TYPE_PARTIAL_LINE; return TRACE_TYPE_HANDLED; } static enum print_line_t print_hex_fmt(struct trace_iterator *iter) { struct trace_seq *s = &iter->seq; unsigned char newline = '\n'; struct trace_entry *entry; struct trace_event *event; entry = iter->ent; SEQ_PUT_HEX_FIELD_RET(s, entry->pid); SEQ_PUT_HEX_FIELD_RET(s, iter->cpu); SEQ_PUT_HEX_FIELD_RET(s, iter->ts); event = ftrace_find_event(entry->type); if (event && event->hex) event->hex(s, entry, 0); SEQ_PUT_FIELD_RET(s, newline); return TRACE_TYPE_HANDLED; } static enum print_line_t print_printk_msg_only(struct trace_iterator *iter) { struct trace_seq *s = &iter->seq; struct trace_entry *entry = iter->ent; struct print_entry *field; int ret; trace_assign_type(field, entry); ret = trace_seq_printf(s, field->buf); if (!ret) return TRACE_TYPE_PARTIAL_LINE; return TRACE_TYPE_HANDLED; } static enum print_line_t print_bin_fmt(struct trace_iterator *iter) { struct trace_seq *s = &iter->seq; struct trace_entry *entry; struct trace_event *event; entry = iter->ent; SEQ_PUT_FIELD_RET(s, entry->pid); SEQ_PUT_FIELD_RET(s, entry->cpu); SEQ_PUT_FIELD_RET(s, iter->ts); event = ftrace_find_event(entry->type); if (event && event->binary) event->binary(s, entry, 0); return TRACE_TYPE_HANDLED; } static int trace_empty(struct trace_iterator *iter) { int cpu; for_each_tracing_cpu(cpu) { if (iter->buffer_iter[cpu]) { if (!ring_buffer_iter_empty(iter->buffer_iter[cpu])) return 0; } else { if (!ring_buffer_empty_cpu(iter->tr->buffer, cpu)) return 0; } } return 1; } static enum print_line_t print_trace_line(struct trace_iterator *iter) { enum print_line_t ret; if (iter->trace && iter->trace->print_line) { ret = iter->trace->print_line(iter); if (ret != TRACE_TYPE_UNHANDLED) return ret; } if (iter->ent->type == TRACE_PRINT && trace_flags & TRACE_ITER_PRINTK && trace_flags & TRACE_ITER_PRINTK_MSGONLY) return print_printk_msg_only(iter); if (trace_flags & TRACE_ITER_BIN) return print_bin_fmt(iter); if (trace_flags & TRACE_ITER_HEX) return print_hex_fmt(iter); if (trace_flags & TRACE_ITER_RAW) return print_raw_fmt(iter); if (iter->iter_flags & TRACE_FILE_LAT_FMT) return print_lat_fmt(iter, iter->idx, iter->cpu); return print_trace_fmt(iter); } static int s_show(struct seq_file *m, void *v) { struct trace_iterator *iter = v; if (iter->ent == NULL) { if (iter->tr) { seq_printf(m, "# tracer: %s\n", iter->trace->name); seq_puts(m, "#\n"); } if (iter->trace && iter->trace->print_header) iter->trace->print_header(m); else if (iter->iter_flags & TRACE_FILE_LAT_FMT) { /* print nothing if the buffers are empty */ if (trace_empty(iter)) return 0; print_trace_header(m, iter); if (!(trace_flags & TRACE_ITER_VERBOSE)) print_lat_help_header(m); } else { if (!(trace_flags & TRACE_ITER_VERBOSE)) print_func_help_header(m); } } else { print_trace_line(iter); trace_print_seq(m, &iter->seq); } return 0; } static struct seq_operations tracer_seq_ops = { .start = s_start, .next = s_next, .stop = s_stop, .show = s_show, }; static struct trace_iterator * __tracing_open(struct inode *inode, struct file *file, int *ret) { struct trace_iterator *iter; struct seq_file *m; int cpu; if (tracing_disabled) { *ret = -ENODEV; return NULL; } iter = kzalloc(sizeof(*iter), GFP_KERNEL); if (!iter) { *ret = -ENOMEM; goto out; } mutex_lock(&trace_types_lock); if (current_trace && current_trace->print_max) iter->tr = &max_tr; else iter->tr = inode->i_private; iter->trace = current_trace; iter->pos = -1; /* Notify the tracer early; before we stop tracing. */ if (iter->trace && iter->trace->open) iter->trace->open(iter); /* Annotate start of buffers if we had overruns */ if (ring_buffer_overruns(iter->tr->buffer)) iter->iter_flags |= TRACE_FILE_ANNOTATE; for_each_tracing_cpu(cpu) { iter->buffer_iter[cpu] = ring_buffer_read_start(iter->tr->buffer, cpu); if (!iter->buffer_iter[cpu]) goto fail_buffer; } /* TODO stop tracer */ *ret = seq_open(file, &tracer_seq_ops); if (*ret) goto fail_buffer; m = file->private_data; m->private = iter; /* stop the trace while dumping */ tracing_stop(); mutex_unlock(&trace_types_lock); out: return iter; fail_buffer: for_each_tracing_cpu(cpu) { if (iter->buffer_iter[cpu]) ring_buffer_read_finish(iter->buffer_iter[cpu]); } mutex_unlock(&trace_types_lock); kfree(iter); return ERR_PTR(-ENOMEM); } int tracing_open_generic(struct inode *inode, struct file *filp) { if (tracing_disabled) return -ENODEV; filp->private_data = inode->i_private; return 0; } int tracing_release(struct inode *inode, struct file *file) { struct seq_file *m = (struct seq_file *)file->private_data; struct trace_iterator *iter = m->private; int cpu; mutex_lock(&trace_types_lock); for_each_tracing_cpu(cpu) { if (iter->buffer_iter[cpu]) ring_buffer_read_finish(iter->buffer_iter[cpu]); } if (iter->trace && iter->trace->close) iter->trace->close(iter); /* reenable tracing if it was previously enabled */ tracing_start(); mutex_unlock(&trace_types_lock); seq_release(inode, file); kfree(iter); return 0; } static int tracing_open(struct inode *inode, struct file *file) { int ret; __tracing_open(inode, file, &ret); return ret; } static int tracing_lt_open(struct inode *inode, struct file *file) { struct trace_iterator *iter; int ret; iter = __tracing_open(inode, file, &ret); if (!ret) iter->iter_flags |= TRACE_FILE_LAT_FMT; return ret; } static void * t_next(struct seq_file *m, void *v, loff_t *pos) { struct tracer *t = m->private; (*pos)++; if (t) t = t->next; m->private = t; return t; } static void *t_start(struct seq_file *m, loff_t *pos) { struct tracer *t = m->private; loff_t l = 0; mutex_lock(&trace_types_lock); for (; t && l < *pos; t = t_next(m, t, &l)) ; return t; } static void t_stop(struct seq_file *m, void *p) { mutex_unlock(&trace_types_lock); } static int t_show(struct seq_file *m, void *v) { struct tracer *t = v; if (!t) return 0; seq_printf(m, "%s", t->name); if (t->next) seq_putc(m, ' '); else seq_putc(m, '\n'); return 0; } static struct seq_operations show_traces_seq_ops = { .start = t_start, .next = t_next, .stop = t_stop, .show = t_show, }; static int show_traces_open(struct inode *inode, struct file *file) { int ret; if (tracing_disabled) return -ENODEV; ret = seq_open(file, &show_traces_seq_ops); if (!ret) { struct seq_file *m = file->private_data; m->private = trace_types; } return ret; } static struct file_operations tracing_fops = { .open = tracing_open, .read = seq_read, .llseek = seq_lseek, .release = tracing_release, }; static struct file_operations tracing_lt_fops = { .open = tracing_lt_open, .read = seq_read, .llseek = seq_lseek, .release = tracing_release, }; static struct file_operations show_traces_fops = { .open = show_traces_open, .read = seq_read, .release = seq_release, }; /* * Only trace on a CPU if the bitmask is set: */ static cpumask_var_t tracing_cpumask; /* * The tracer itself will not take this lock, but still we want * to provide a consistent cpumask to user-space: */ static DEFINE_MUTEX(tracing_cpumask_update_lock); /* * Temporary storage for the character representation of the * CPU bitmask (and one more byte for the newline): */ static char mask_str[NR_CPUS + 1]; static ssize_t tracing_cpumask_read(struct file *filp, char __user *ubuf, size_t count, loff_t *ppos) { int len; mutex_lock(&tracing_cpumask_update_lock); len = cpumask_scnprintf(mask_str, count, tracing_cpumask); if (count - len < 2) { count = -EINVAL; goto out_err; } len += sprintf(mask_str + len, "\n"); count = simple_read_from_buffer(ubuf, count, ppos, mask_str, NR_CPUS+1); out_err: mutex_unlock(&tracing_cpumask_update_lock); return count; } static ssize_t tracing_cpumask_write(struct file *filp, const char __user *ubuf, size_t count, loff_t *ppos) { int err, cpu; cpumask_var_t tracing_cpumask_new; if (!alloc_cpumask_var(&tracing_cpumask_new, GFP_KERNEL)) return -ENOMEM; mutex_lock(&tracing_cpumask_update_lock); err = cpumask_parse_user(ubuf, count, tracing_cpumask_new); if (err) goto err_unlock; local_irq_disable(); __raw_spin_lock(&ftrace_max_lock); for_each_tracing_cpu(cpu) { /* * Increase/decrease the disabled counter if we are * about to flip a bit in the cpumask: */ if (cpumask_test_cpu(cpu, tracing_cpumask) && !cpumask_test_cpu(cpu, tracing_cpumask_new)) { atomic_inc(&global_trace.data[cpu]->disabled); } if (!cpumask_test_cpu(cpu, tracing_cpumask) && cpumask_test_cpu(cpu, tracing_cpumask_new)) { atomic_dec(&global_trace.data[cpu]->disabled); } } __raw_spin_unlock(&ftrace_max_lock); local_irq_enable(); cpumask_copy(tracing_cpumask, tracing_cpumask_new); mutex_unlock(&tracing_cpumask_update_lock); free_cpumask_var(tracing_cpumask_new); return count; err_unlock: mutex_unlock(&tracing_cpumask_update_lock); free_cpumask_var(tracing_cpumask); return err; } static struct file_operations tracing_cpumask_fops = { .open = tracing_open_generic, .read = tracing_cpumask_read, .write = tracing_cpumask_write, }; static ssize_t tracing_trace_options_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos) { int i; char *buf; int r = 0; int len = 0; u32 tracer_flags = current_trace->flags->val; struct tracer_opt *trace_opts = current_trace->flags->opts; /* calulate max size */ for (i = 0; trace_options[i]; i++) { len += strlen(trace_options[i]); len += 3; /* "no" and space */ } /* * Increase the size with names of options specific * of the current tracer. */ for (i = 0; trace_opts[i].name; i++) { len += strlen(trace_opts[i].name); len += 3; /* "no" and space */ } /* +2 for \n and \0 */ buf = kmalloc(len + 2, GFP_KERNEL); if (!buf) return -ENOMEM; for (i = 0; trace_options[i]; i++) { if (trace_flags & (1 << i)) r += sprintf(buf + r, "%s ", trace_options[i]); else r += sprintf(buf + r, "no%s ", trace_options[i]); } for (i = 0; trace_opts[i].name; i++) { if (tracer_flags & trace_opts[i].bit) r += sprintf(buf + r, "%s ", trace_opts[i].name); else r += sprintf(buf + r, "no%s ", trace_opts[i].name); } r += sprintf(buf + r, "\n"); WARN_ON(r >= len + 2); r = simple_read_from_buffer(ubuf, cnt, ppos, buf, r); kfree(buf); return r; } /* Try to assign a tracer specific option */ static int set_tracer_option(struct tracer *trace, char *cmp, int neg) { struct tracer_flags *trace_flags = trace->flags; struct tracer_opt *opts = NULL; int ret = 0, i = 0; int len; for (i = 0; trace_flags->opts[i].name; i++) { opts = &trace_flags->opts[i]; len = strlen(opts->name); if (strncmp(cmp, opts->name, len) == 0) { ret = trace->set_flag(trace_flags->val, opts->bit, !neg); break; } } /* Not found */ if (!trace_flags->opts[i].name) return -EINVAL; /* Refused to handle */ if (ret) return ret; if (neg) trace_flags->val &= ~opts->bit; else trace_flags->val |= opts->bit; return 0; } static ssize_t tracing_trace_options_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *ppos) { char buf[64]; char *cmp = buf; int neg = 0; int ret; int i; if (cnt >= sizeof(buf)) return -EINVAL; if (copy_from_user(&buf, ubuf, cnt)) return -EFAULT; buf[cnt] = 0; if (strncmp(buf, "no", 2) == 0) { neg = 1; cmp += 2; } for (i = 0; trace_options[i]; i++) { int len = strlen(trace_options[i]); if (strncmp(cmp, trace_options[i], len) == 0) { if (neg) trace_flags &= ~(1 << i); else trace_flags |= (1 << i); break; } } /* If no option could be set, test the specific tracer options */ if (!trace_options[i]) { ret = set_tracer_option(current_trace, cmp, neg); if (ret) return ret; } filp->f_pos += cnt; return cnt; } static struct file_operations tracing_iter_fops = { .open = tracing_open_generic, .read = tracing_trace_options_read, .write = tracing_trace_options_write, }; static const char readme_msg[] = "tracing mini-HOWTO:\n\n" "# mkdir /debug\n" "# mount -t debugfs nodev /debug\n\n" "# cat /debug/tracing/available_tracers\n" "wakeup preemptirqsoff preemptoff irqsoff ftrace sched_switch none\n\n" "# cat /debug/tracing/current_tracer\n" "none\n" "# echo sched_switch > /debug/tracing/current_tracer\n" "# cat /debug/tracing/current_tracer\n" "sched_switch\n" "# cat /debug/tracing/trace_options\n" "noprint-parent nosym-offset nosym-addr noverbose\n" "# echo print-parent > /debug/tracing/trace_options\n" "# echo 1 > /debug/tracing/tracing_enabled\n" "# cat /debug/tracing/trace > /tmp/trace.txt\n" "echo 0 > /debug/tracing/tracing_enabled\n" ; static ssize_t tracing_readme_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos) { return simple_read_from_buffer(ubuf, cnt, ppos, readme_msg, strlen(readme_msg)); } static struct file_operations tracing_readme_fops = { .open = tracing_open_generic, .read = tracing_readme_read, }; static ssize_t tracing_ctrl_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos) { char buf[64]; int r; r = sprintf(buf, "%u\n", tracer_enabled); return simple_read_from_buffer(ubuf, cnt, ppos, buf, r); } static ssize_t tracing_ctrl_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *ppos) { struct trace_array *tr = filp->private_data; char buf[64]; long val; int ret; if (cnt >= sizeof(buf)) return -EINVAL; if (copy_from_user(&buf, ubuf, cnt)) return -EFAULT; buf[cnt] = 0; ret = strict_strtoul(buf, 10, &val); if (ret < 0) return ret; val = !!val; mutex_lock(&trace_types_lock); if (tracer_enabled ^ val) { if (val) { tracer_enabled = 1; if (current_trace->start) current_trace->start(tr); tracing_start(); } else { tracer_enabled = 0; tracing_stop(); if (current_trace->stop) current_trace->stop(tr); } } mutex_unlock(&trace_types_lock); filp->f_pos += cnt; return cnt; } static ssize_t tracing_set_trace_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos) { char buf[max_tracer_type_len+2]; int r; mutex_lock(&trace_types_lock); if (current_trace) r = sprintf(buf, "%s\n", current_trace->name); else r = sprintf(buf, "\n"); mutex_unlock(&trace_types_lock); return simple_read_from_buffer(ubuf, cnt, ppos, buf, r); } static int tracing_set_tracer(const char *buf) { struct trace_array *tr = &global_trace; struct tracer *t; int ret = 0; mutex_lock(&trace_types_lock); for (t = trace_types; t; t = t->next) { if (strcmp(t->name, buf) == 0) break; } if (!t) { ret = -EINVAL; goto out; } if (t == current_trace) goto out; trace_branch_disable(); if (current_trace && current_trace->reset) current_trace->reset(tr); current_trace = t; if (t->init) { ret = t->init(tr); if (ret) goto out; } trace_branch_enable(tr); out: mutex_unlock(&trace_types_lock); return ret; } static ssize_t tracing_set_trace_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *ppos) { char buf[max_tracer_type_len+1]; int i; size_t ret; int err; ret = cnt; if (cnt > max_tracer_type_len) cnt = max_tracer_type_len; if (copy_from_user(&buf, ubuf, cnt)) return -EFAULT; buf[cnt] = 0; /* strip ending whitespace. */ for (i = cnt - 1; i > 0 && isspace(buf[i]); i--) buf[i] = 0; err = tracing_set_tracer(buf); if (err) return err; filp->f_pos += ret; return ret; } static ssize_t tracing_max_lat_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos) { unsigned long *ptr = filp->private_data; char buf[64]; int r; r = snprintf(buf, sizeof(buf), "%ld\n", *ptr == (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr)); if (r > sizeof(buf)) r = sizeof(buf); return simple_read_from_buffer(ubuf, cnt, ppos, buf, r); } static ssize_t tracing_max_lat_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *ppos) { long *ptr = filp->private_data; char buf[64]; long val; int ret; if (cnt >= sizeof(buf)) return -EINVAL; if (copy_from_user(&buf, ubuf, cnt)) return -EFAULT; buf[cnt] = 0; ret = strict_strtoul(buf, 10, &val); if (ret < 0) return ret; *ptr = val * 1000; return cnt; } static atomic_t tracing_reader; static int tracing_open_pipe(struct inode *inode, struct file *filp) { struct trace_iterator *iter; if (tracing_disabled) return -ENODEV; /* We only allow for reader of the pipe */ if (atomic_inc_return(&tracing_reader) != 1) { atomic_dec(&tracing_reader); return -EBUSY; } /* create a buffer to store the information to pass to userspace */ iter = kzalloc(sizeof(*iter), GFP_KERNEL); if (!iter) return -ENOMEM; if (!alloc_cpumask_var(&iter->started, GFP_KERNEL)) { kfree(iter); return -ENOMEM; } mutex_lock(&trace_types_lock); /* trace pipe does not show start of buffer */ cpumask_setall(iter->started); iter->tr = &global_trace; iter->trace = current_trace; filp->private_data = iter; if (iter->trace->pipe_open) iter->trace->pipe_open(iter); mutex_unlock(&trace_types_lock); return 0; } static int tracing_release_pipe(struct inode *inode, struct file *file) { struct trace_iterator *iter = file->private_data; free_cpumask_var(iter->started); kfree(iter); atomic_dec(&tracing_reader); return 0; } static unsigned int tracing_poll_pipe(struct file *filp, poll_table *poll_table) { struct trace_iterator *iter = filp->private_data; if (trace_flags & TRACE_ITER_BLOCK) { /* * Always select as readable when in blocking mode */ return POLLIN | POLLRDNORM; } else { if (!trace_empty(iter)) return POLLIN | POLLRDNORM; poll_wait(filp, &trace_wait, poll_table); if (!trace_empty(iter)) return POLLIN | POLLRDNORM; return 0; } } /* * Consumer reader. */ static ssize_t tracing_read_pipe(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos) { struct trace_iterator *iter = filp->private_data; ssize_t sret; /* return any leftover data */ sret = trace_seq_to_user(&iter->seq, ubuf, cnt); if (sret != -EBUSY) return sret; trace_seq_reset(&iter->seq); mutex_lock(&trace_types_lock); if (iter->trace->read) { sret = iter->trace->read(iter, filp, ubuf, cnt, ppos); if (sret) goto out; } waitagain: sret = 0; while (trace_empty(iter)) { if ((filp->f_flags & O_NONBLOCK)) { sret = -EAGAIN; goto out; } /* * This is a make-shift waitqueue. The reason we don't use * an actual wait queue is because: * 1) we only ever have one waiter * 2) the tracing, traces all functions, we don't want * the overhead of calling wake_up and friends * (and tracing them too) * Anyway, this is really very primitive wakeup. */ set_current_state(TASK_INTERRUPTIBLE); iter->tr->waiter = current; mutex_unlock(&trace_types_lock); /* sleep for 100 msecs, and try again. */ schedule_timeout(HZ/10); mutex_lock(&trace_types_lock); iter->tr->waiter = NULL; if (signal_pending(current)) { sret = -EINTR; goto out; } if (iter->trace != current_trace) goto out; /* * We block until we read something and tracing is disabled. * We still block if tracing is disabled, but we have never * read anything. This allows a user to cat this file, and * then enable tracing. But after we have read something, * we give an EOF when tracing is again disabled. * * iter->pos will be 0 if we haven't read anything. */ if (!tracer_enabled && iter->pos) break; continue; } /* stop when tracing is finished */ if (trace_empty(iter)) goto out; if (cnt >= PAGE_SIZE) cnt = PAGE_SIZE - 1; /* reset all but tr, trace, and overruns */ memset(&iter->seq, 0, sizeof(struct trace_iterator) - offsetof(struct trace_iterator, seq)); iter->pos = -1; while (find_next_entry_inc(iter) != NULL) { enum print_line_t ret; int len = iter->seq.len; ret = print_trace_line(iter); if (ret == TRACE_TYPE_PARTIAL_LINE) { /* don't print partial lines */ iter->seq.len = len; break; } trace_consume(iter); if (iter->seq.len >= cnt) break; } /* Now copy what we have to the user */ sret = trace_seq_to_user(&iter->seq, ubuf, cnt); if (iter->seq.readpos >= iter->seq.len) trace_seq_reset(&iter->seq); /* * If there was nothing to send to user, inspite of consuming trace * entries, go back to wait for more entries. */ if (sret == -EBUSY) goto waitagain; out: mutex_unlock(&trace_types_lock); return sret; } static ssize_t tracing_entries_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos) { struct trace_array *tr = filp->private_data; char buf[64]; int r; r = sprintf(buf, "%lu\n", tr->entries >> 10); return simple_read_from_buffer(ubuf, cnt, ppos, buf, r); } static ssize_t tracing_entries_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *ppos) { unsigned long val; char buf[64]; int ret, cpu; if (cnt >= sizeof(buf)) return -EINVAL; if (copy_from_user(&buf, ubuf, cnt)) return -EFAULT; buf[cnt] = 0; ret = strict_strtoul(buf, 10, &val); if (ret < 0) return ret; /* must have at least 1 entry */ if (!val) return -EINVAL; mutex_lock(&trace_types_lock); tracing_stop(); /* disable all cpu buffers */ for_each_tracing_cpu(cpu) { if (global_trace.data[cpu]) atomic_inc(&global_trace.data[cpu]->disabled); if (max_tr.data[cpu]) atomic_inc(&max_tr.data[cpu]->disabled); } /* value is in KB */ val <<= 10; if (val != global_trace.entries) { ret = ring_buffer_resize(global_trace.buffer, val); if (ret < 0) { cnt = ret; goto out; } ret = ring_buffer_resize(max_tr.buffer, val); if (ret < 0) { int r; cnt = ret; r = ring_buffer_resize(global_trace.buffer, global_trace.entries); if (r < 0) { /* AARGH! We are left with different * size max buffer!!!! */ WARN_ON(1); tracing_disabled = 1; } goto out; } global_trace.entries = val; } filp->f_pos += cnt; /* If check pages failed, return ENOMEM */ if (tracing_disabled) cnt = -ENOMEM; out: for_each_tracing_cpu(cpu) { if (global_trace.data[cpu]) atomic_dec(&global_trace.data[cpu]->disabled); if (max_tr.data[cpu]) atomic_dec(&max_tr.data[cpu]->disabled); } tracing_start(); max_tr.entries = global_trace.entries; mutex_unlock(&trace_types_lock); return cnt; } static int mark_printk(const char *fmt, ...) { int ret; va_list args; va_start(args, fmt); ret = trace_vprintk(0, -1, fmt, args); va_end(args); return ret; } static ssize_t tracing_mark_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *fpos) { char *buf; char *end; if (tracing_disabled) return -EINVAL; if (cnt > TRACE_BUF_SIZE) cnt = TRACE_BUF_SIZE; buf = kmalloc(cnt + 1, GFP_KERNEL); if (buf == NULL) return -ENOMEM; if (copy_from_user(buf, ubuf, cnt)) { kfree(buf); return -EFAULT; } /* Cut from the first nil or newline. */ buf[cnt] = '\0'; end = strchr(buf, '\n'); if (end) *end = '\0'; cnt = mark_printk("%s\n", buf); kfree(buf); *fpos += cnt; return cnt; } static struct file_operations tracing_max_lat_fops = { .open = tracing_open_generic, .read = tracing_max_lat_read, .write = tracing_max_lat_write, }; static struct file_operations tracing_ctrl_fops = { .open = tracing_open_generic, .read = tracing_ctrl_read, .write = tracing_ctrl_write, }; static struct file_operations set_tracer_fops = { .open = tracing_open_generic, .read = tracing_set_trace_read, .write = tracing_set_trace_write, }; static struct file_operations tracing_pipe_fops = { .open = tracing_open_pipe, .poll = tracing_poll_pipe, .read = tracing_read_pipe, .release = tracing_release_pipe, }; static struct file_operations tracing_entries_fops = { .open = tracing_open_generic, .read = tracing_entries_read, .write = tracing_entries_write, }; static struct file_operations tracing_mark_fops = { .open = tracing_open_generic, .write = tracing_mark_write, }; #ifdef CONFIG_DYNAMIC_FTRACE int __weak ftrace_arch_read_dyn_info(char *buf, int size) { return 0; } static ssize_t tracing_read_dyn_info(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos) { static char ftrace_dyn_info_buffer[1024]; static DEFINE_MUTEX(dyn_info_mutex); unsigned long *p = filp->private_data; char *buf = ftrace_dyn_info_buffer; int size = ARRAY_SIZE(ftrace_dyn_info_buffer); int r; mutex_lock(&dyn_info_mutex); r = sprintf(buf, "%ld ", *p); r += ftrace_arch_read_dyn_info(buf+r, (size-1)-r); buf[r++] = '\n'; r = simple_read_from_buffer(ubuf, cnt, ppos, buf, r); mutex_unlock(&dyn_info_mutex); return r; } static struct file_operations tracing_dyn_info_fops = { .open = tracing_open_generic, .read = tracing_read_dyn_info, }; #endif static struct dentry *d_tracer; struct dentry *tracing_init_dentry(void) { static int once; if (d_tracer) return d_tracer; d_tracer = debugfs_create_dir("tracing", NULL); if (!d_tracer && !once) { once = 1; pr_warning("Could not create debugfs directory 'tracing'\n"); return NULL; } return d_tracer; } #ifdef CONFIG_FTRACE_SELFTEST /* Let selftest have access to static functions in this file */ #include "trace_selftest.c" #endif static __init int tracer_init_debugfs(void) { struct dentry *d_tracer; struct dentry *entry; d_tracer = tracing_init_dentry(); entry = debugfs_create_file("tracing_enabled", 0644, d_tracer, &global_trace, &tracing_ctrl_fops); if (!entry) pr_warning("Could not create debugfs 'tracing_enabled' entry\n"); entry = debugfs_create_file("trace_options", 0644, d_tracer, NULL, &tracing_iter_fops); if (!entry) pr_warning("Could not create debugfs 'trace_options' entry\n"); entry = debugfs_create_file("tracing_cpumask", 0644, d_tracer, NULL, &tracing_cpumask_fops); if (!entry) pr_warning("Could not create debugfs 'tracing_cpumask' entry\n"); entry = debugfs_create_file("latency_trace", 0444, d_tracer, &global_trace, &tracing_lt_fops); if (!entry) pr_warning("Could not create debugfs 'latency_trace' entry\n"); entry = debugfs_create_file("trace", 0444, d_tracer, &global_trace, &tracing_fops); if (!entry) pr_warning("Could not create debugfs 'trace' entry\n"); entry = debugfs_create_file("available_tracers", 0444, d_tracer, &global_trace, &show_traces_fops); if (!entry) pr_warning("Could not create debugfs 'available_tracers' entry\n"); entry = debugfs_create_file("current_tracer", 0444, d_tracer, &global_trace, &set_tracer_fops); if (!entry) pr_warning("Could not create debugfs 'current_tracer' entry\n"); entry = debugfs_create_file("tracing_max_latency", 0644, d_tracer, &tracing_max_latency, &tracing_max_lat_fops); if (!entry) pr_warning("Could not create debugfs " "'tracing_max_latency' entry\n"); entry = debugfs_create_file("tracing_thresh", 0644, d_tracer, &tracing_thresh, &tracing_max_lat_fops); if (!entry) pr_warning("Could not create debugfs " "'tracing_thresh' entry\n"); entry = debugfs_create_file("README", 0644, d_tracer, NULL, &tracing_readme_fops); if (!entry) pr_warning("Could not create debugfs 'README' entry\n"); entry = debugfs_create_file("trace_pipe", 0644, d_tracer, NULL, &tracing_pipe_fops); if (!entry) pr_warning("Could not create debugfs " "'trace_pipe' entry\n"); entry = debugfs_create_file("buffer_size_kb", 0644, d_tracer, &global_trace, &tracing_entries_fops); if (!entry) pr_warning("Could not create debugfs " "'buffer_size_kb' entry\n"); entry = debugfs_create_file("trace_marker", 0220, d_tracer, NULL, &tracing_mark_fops); if (!entry) pr_warning("Could not create debugfs " "'trace_marker' entry\n"); #ifdef CONFIG_DYNAMIC_FTRACE entry = debugfs_create_file("dyn_ftrace_total_info", 0444, d_tracer, &ftrace_update_tot_cnt, &tracing_dyn_info_fops); if (!entry) pr_warning("Could not create debugfs " "'dyn_ftrace_total_info' entry\n"); #endif #ifdef CONFIG_SYSPROF_TRACER init_tracer_sysprof_debugfs(d_tracer); #endif return 0; } int trace_vprintk(unsigned long ip, int depth, const char *fmt, va_list args) { static DEFINE_SPINLOCK(trace_buf_lock); static char trace_buf[TRACE_BUF_SIZE]; struct ring_buffer_event *event; struct trace_array *tr = &global_trace; struct trace_array_cpu *data; int cpu, len = 0, size, pc; struct print_entry *entry; unsigned long irq_flags; if (tracing_disabled || tracing_selftest_running) return 0; pc = preempt_count(); preempt_disable_notrace(); cpu = raw_smp_processor_id(); data = tr->data[cpu]; if (unlikely(atomic_read(&data->disabled))) goto out; pause_graph_tracing(); spin_lock_irqsave(&trace_buf_lock, irq_flags); len = vsnprintf(trace_buf, TRACE_BUF_SIZE, fmt, args); len = min(len, TRACE_BUF_SIZE-1); trace_buf[len] = 0; size = sizeof(*entry) + len + 1; event = ring_buffer_lock_reserve(tr->buffer, size, &irq_flags); if (!event) goto out_unlock; entry = ring_buffer_event_data(event); tracing_generic_entry_update(&entry->ent, irq_flags, pc); entry->ent.type = TRACE_PRINT; entry->ip = ip; entry->depth = depth; memcpy(&entry->buf, trace_buf, len); entry->buf[len] = 0; ring_buffer_unlock_commit(tr->buffer, event, irq_flags); out_unlock: spin_unlock_irqrestore(&trace_buf_lock, irq_flags); unpause_graph_tracing(); out: preempt_enable_notrace(); return len; } EXPORT_SYMBOL_GPL(trace_vprintk); int __ftrace_printk(unsigned long ip, const char *fmt, ...) { int ret; va_list ap; if (!(trace_flags & TRACE_ITER_PRINTK)) return 0; va_start(ap, fmt); ret = trace_vprintk(ip, task_curr_ret_stack(current), fmt, ap); va_end(ap); return ret; } EXPORT_SYMBOL_GPL(__ftrace_printk); int __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap) { if (!(trace_flags & TRACE_ITER_PRINTK)) return 0; return trace_vprintk(ip, task_curr_ret_stack(current), fmt, ap); } EXPORT_SYMBOL_GPL(__ftrace_vprintk); static int trace_panic_handler(struct notifier_block *this, unsigned long event, void *unused) { if (ftrace_dump_on_oops) ftrace_dump(); return NOTIFY_OK; } static struct notifier_block trace_panic_notifier = { .notifier_call = trace_panic_handler, .next = NULL, .priority = 150 /* priority: INT_MAX >= x >= 0 */ }; static int trace_die_handler(struct notifier_block *self, unsigned long val, void *data) { switch (val) { case DIE_OOPS: if (ftrace_dump_on_oops) ftrace_dump(); break; default: break; } return NOTIFY_OK; } static struct notifier_block trace_die_notifier = { .notifier_call = trace_die_handler, .priority = 200 }; /* * printk is set to max of 1024, we really don't need it that big. * Nothing should be printing 1000 characters anyway. */ #define TRACE_MAX_PRINT 1000 /* * Define here KERN_TRACE so that we have one place to modify * it if we decide to change what log level the ftrace dump * should be at. */ #define KERN_TRACE KERN_EMERG static void trace_printk_seq(struct trace_seq *s) { /* Probably should print a warning here. */ if (s->len >= 1000) s->len = 1000; /* should be zero ended, but we are paranoid. */ s->buffer[s->len] = 0; printk(KERN_TRACE "%s", s->buffer); trace_seq_reset(s); } void ftrace_dump(void) { static DEFINE_SPINLOCK(ftrace_dump_lock); /* use static because iter can be a bit big for the stack */ static struct trace_iterator iter; static int dump_ran; unsigned long flags; int cnt = 0, cpu; /* only one dump */ spin_lock_irqsave(&ftrace_dump_lock, flags); if (dump_ran) goto out; dump_ran = 1; /* No turning back! */ tracing_off(); ftrace_kill(); for_each_tracing_cpu(cpu) { atomic_inc(&global_trace.data[cpu]->disabled); } /* don't look at user memory in panic mode */ trace_flags &= ~TRACE_ITER_SYM_USEROBJ; printk(KERN_TRACE "Dumping ftrace buffer:\n"); iter.tr = &global_trace; iter.trace = current_trace; /* * We need to stop all tracing on all CPUS to read the * the next buffer. This is a bit expensive, but is * not done often. We fill all what we can read, * and then release the locks again. */ while (!trace_empty(&iter)) { if (!cnt) printk(KERN_TRACE "---------------------------------\n"); cnt++; /* reset all but tr, trace, and overruns */ memset(&iter.seq, 0, sizeof(struct trace_iterator) - offsetof(struct trace_iterator, seq)); iter.iter_flags |= TRACE_FILE_LAT_FMT; iter.pos = -1; if (find_next_entry_inc(&iter) != NULL) { print_trace_line(&iter); trace_consume(&iter); } trace_printk_seq(&iter.seq); } if (!cnt) printk(KERN_TRACE " (ftrace buffer empty)\n"); else printk(KERN_TRACE "---------------------------------\n"); out: spin_unlock_irqrestore(&ftrace_dump_lock, flags); } __init static int tracer_alloc_buffers(void) { struct trace_array_cpu *data; int i; int ret = -ENOMEM; if (!alloc_cpumask_var(&tracing_buffer_mask, GFP_KERNEL)) goto out; if (!alloc_cpumask_var(&tracing_cpumask, GFP_KERNEL)) goto out_free_buffer_mask; cpumask_copy(tracing_buffer_mask, cpu_possible_mask); cpumask_copy(tracing_cpumask, cpu_all_mask); /* TODO: make the number of buffers hot pluggable with CPUS */ global_trace.buffer = ring_buffer_alloc(trace_buf_size, TRACE_BUFFER_FLAGS); if (!global_trace.buffer) { printk(KERN_ERR "tracer: failed to allocate ring buffer!\n"); WARN_ON(1); goto out_free_cpumask; } global_trace.entries = ring_buffer_size(global_trace.buffer); #ifdef CONFIG_TRACER_MAX_TRACE max_tr.buffer = ring_buffer_alloc(trace_buf_size, TRACE_BUFFER_FLAGS); if (!max_tr.buffer) { printk(KERN_ERR "tracer: failed to allocate max ring buffer!\n"); WARN_ON(1); ring_buffer_free(global_trace.buffer); goto out_free_cpumask; } max_tr.entries = ring_buffer_size(max_tr.buffer); WARN_ON(max_tr.entries != global_trace.entries); #endif /* Allocate the first page for all buffers */ for_each_tracing_cpu(i) { data = global_trace.data[i] = &per_cpu(global_trace_cpu, i); max_tr.data[i] = &per_cpu(max_data, i); } trace_init_cmdlines(); register_tracer(&nop_trace); current_trace = &nop_trace; #ifdef CONFIG_BOOT_TRACER register_tracer(&boot_tracer); #endif /* All seems OK, enable tracing */ tracing_disabled = 0; atomic_notifier_chain_register(&panic_notifier_list, &trace_panic_notifier); register_die_notifier(&trace_die_notifier); ret = 0; out_free_cpumask: free_cpumask_var(tracing_cpumask); out_free_buffer_mask: free_cpumask_var(tracing_buffer_mask); out: return ret; } __init static int clear_boot_tracer(void) { /* * The default tracer at boot buffer is an init section. * This function is called in lateinit. If we did not * find the boot tracer, then clear it out, to prevent * later registration from accessing the buffer that is * about to be freed. */ if (!default_bootup_tracer) return 0; printk(KERN_INFO "ftrace bootup tracer '%s' not registered.\n", default_bootup_tracer); default_bootup_tracer = NULL; return 0; } early_initcall(tracer_alloc_buffers); fs_initcall(tracer_init_debugfs); late_initcall(clear_boot_tracer);