/* * 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 #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; /* * On boot up, the ring buffer is set to the minimum size, so that * we do not waste memory on systems that are not using tracing. */ static int ring_buffer_expanded; /* * 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 trace_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. */ static 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 which cpu buffers are currently read in trace_pipe */ static cpumask_var_t tracing_reader_cpumask; #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; /* We are using ftrace early, expand it */ ring_buffer_expanded = 1; 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); unsigned long long ns2usecs(cycle_t nsec) { nsec += 500; do_div(nsec, 1000); return nsec; } /* * 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); cycle_t ftrace_now(int cpu) { u64 ts; /* Early boot up does not have a buffer yet */ if (!global_trace.buffer) return trace_clock_local(); ts = ring_buffer_time_stamp(global_trace.buffer, cpu); ring_buffer_normalize_time_stamp(global_trace.buffer, cpu, &ts); return ts; } /* * 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_ITER_CONTEXT_INFO | TRACE_ITER_SLEEP_TIME; /** * 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", "trace_printk", "ftrace_preempt", "branch", "annotate", "userstacktrace", "sym-userobj", "printk-msg-only", "context-info", "latency-format", "global-clock", "sleep-time", 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(tsk); } ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf, size_t cnt) { int len; int ret; if (!cnt) return 0; 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 == cnt) return -EFAULT; cnt -= ret; s->readpos += cnt; return cnt; } static ssize_t trace_seq_to_buffer(struct trace_seq *s, void *buf, size_t cnt) { int len; void *ret; if (s->len <= s->readpos) return -EBUSY; len = s->len - s->readpos; if (cnt > len) cnt = len; ret = memcpy(buf, s->buffer + s->readpos, cnt); if (!ret) return -EFAULT; s->readpos += cnt; 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_init(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) __releases(kernel_lock) __acquires(kernel_lock) { 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; if (!type->wait_pipe) type->wait_pipe = default_wait_pipe; #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) goto out_unlock; if (strncmp(default_bootup_tracer, type->name, BOOTUP_TRACER_SIZE)) goto out_unlock; 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 out_unlock: 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 (type == current_trace && tracer_enabled) { tracer_enabled = 0; tracing_stop(); if (current_trace->stop) current_trace->stop(&global_trace); current_trace = &nop_trace; } 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 #define NO_CMDLINE_MAP UINT_MAX 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 raw_spinlock_t trace_cmdline_lock = __RAW_SPIN_LOCK_UNLOCKED; /* temporary disable recording */ static atomic_t trace_record_cmdline_disabled __read_mostly; static void trace_init_cmdlines(void) { memset(&map_pid_to_cmdline, NO_CMDLINE_MAP, sizeof(map_pid_to_cmdline)); memset(&map_cmdline_to_pid, NO_CMDLINE_MAP, 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 pid, 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 (!__raw_spin_trylock(&trace_cmdline_lock)) return; idx = map_pid_to_cmdline[tsk->pid]; if (idx == NO_CMDLINE_MAP) { idx = (cmdline_idx + 1) % SAVED_CMDLINES; /* * Check whether the cmdline buffer at idx has a pid * mapped. We are going to overwrite that entry so we * need to clear the map_pid_to_cmdline. Otherwise we * would read the new comm for the old pid. */ pid = map_cmdline_to_pid[idx]; if (pid != NO_CMDLINE_MAP) map_pid_to_cmdline[pid] = NO_CMDLINE_MAP; map_cmdline_to_pid[idx] = tsk->pid; map_pid_to_cmdline[tsk->pid] = idx; cmdline_idx = idx; } memcpy(&saved_cmdlines[idx], tsk->comm, TASK_COMM_LEN); __raw_spin_unlock(&trace_cmdline_lock); } void trace_find_cmdline(int pid, char comm[]) { unsigned map; if (!pid) { strcpy(comm, ""); return; } if (pid > PID_MAX_DEFAULT) { strcpy(comm, "<...>"); return; } __raw_spin_lock(&trace_cmdline_lock); map = map_pid_to_cmdline[pid]; if (map != NO_CMDLINE_MAP) strcpy(comm, saved_cmdlines[map]); else strcpy(comm, "<...>"); __raw_spin_unlock(&trace_cmdline_lock); } void tracing_record_cmdline(struct task_struct *tsk) { if (atomic_read(&trace_record_cmdline_disabled) || !tracer_enabled || !tracing_is_on()) 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); } struct ring_buffer_event *trace_buffer_lock_reserve(struct trace_array *tr, unsigned char type, unsigned long len, unsigned long flags, int pc) { struct ring_buffer_event *event; event = ring_buffer_lock_reserve(tr->buffer, len); if (event != NULL) { struct trace_entry *ent = ring_buffer_event_data(event); tracing_generic_entry_update(ent, flags, pc); ent->type = type; } return event; } static void ftrace_trace_stack(struct trace_array *tr, unsigned long flags, int skip, int pc); static void ftrace_trace_userstack(struct trace_array *tr, unsigned long flags, int pc); static inline void __trace_buffer_unlock_commit(struct trace_array *tr, struct ring_buffer_event *event, unsigned long flags, int pc, int wake) { ring_buffer_unlock_commit(tr->buffer, event); ftrace_trace_stack(tr, flags, 6, pc); ftrace_trace_userstack(tr, flags, pc); if (wake) trace_wake_up(); } void trace_buffer_unlock_commit(struct trace_array *tr, struct ring_buffer_event *event, unsigned long flags, int pc) { __trace_buffer_unlock_commit(tr, event, flags, pc, 1); } struct ring_buffer_event * trace_current_buffer_lock_reserve(unsigned char type, unsigned long len, unsigned long flags, int pc) { return trace_buffer_lock_reserve(&global_trace, type, len, flags, pc); } void trace_current_buffer_unlock_commit(struct ring_buffer_event *event, unsigned long flags, int pc) { return __trace_buffer_unlock_commit(&global_trace, event, flags, pc, 1); } void trace_nowake_buffer_unlock_commit(struct ring_buffer_event *event, unsigned long flags, int pc) { return __trace_buffer_unlock_commit(&global_trace, event, flags, pc, 0); } void trace_function(struct trace_array *tr, unsigned long ip, unsigned long parent_ip, unsigned long flags, int pc) { struct ring_buffer_event *event; struct ftrace_entry *entry; /* If we are reading the ring buffer, don't trace */ if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled)))) return; event = trace_buffer_lock_reserve(tr, TRACE_FN, sizeof(*entry), flags, pc); if (!event) return; entry = ring_buffer_event_data(event); entry->ip = ip; entry->parent_ip = parent_ip; ring_buffer_unlock_commit(tr->buffer, event); } #ifdef CONFIG_FUNCTION_GRAPH_TRACER static int __trace_graph_entry(struct trace_array *tr, struct ftrace_graph_ent *trace, unsigned long flags, int pc) { struct ring_buffer_event *event; struct ftrace_graph_ent_entry *entry; if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled)))) return 0; event = trace_buffer_lock_reserve(&global_trace, TRACE_GRAPH_ENT, sizeof(*entry), flags, pc); if (!event) return 0; entry = ring_buffer_event_data(event); entry->graph_ent = *trace; ring_buffer_unlock_commit(global_trace.buffer, event); return 1; } static void __trace_graph_return(struct trace_array *tr, struct ftrace_graph_ret *trace, unsigned long flags, int pc) { struct ring_buffer_event *event; struct ftrace_graph_ret_entry *entry; if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled)))) return; event = trace_buffer_lock_reserve(&global_trace, TRACE_GRAPH_RET, sizeof(*entry), flags, pc); if (!event) return; entry = ring_buffer_event_data(event); entry->ret = *trace; ring_buffer_unlock_commit(global_trace.buffer, event); } #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, ip, parent_ip, flags, pc); } static void __ftrace_trace_stack(struct trace_array *tr, unsigned long flags, int skip, int pc) { #ifdef CONFIG_STACKTRACE struct ring_buffer_event *event; struct stack_entry *entry; struct stack_trace trace; event = trace_buffer_lock_reserve(tr, TRACE_STACK, sizeof(*entry), flags, pc); if (!event) return; entry = ring_buffer_event_data(event); 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); #endif } static void ftrace_trace_stack(struct trace_array *tr, unsigned long flags, int skip, int pc) { if (!(trace_flags & TRACE_ITER_STACKTRACE)) return; __ftrace_trace_stack(tr, flags, skip, pc); } void __trace_stack(struct trace_array *tr, unsigned long flags, int skip, int pc) { __ftrace_trace_stack(tr, flags, skip, pc); } static void ftrace_trace_userstack(struct trace_array *tr, unsigned long flags, int pc) { #ifdef CONFIG_STACKTRACE struct ring_buffer_event *event; struct userstack_entry *entry; struct stack_trace trace; if (!(trace_flags & TRACE_ITER_USERSTACKTRACE)) return; event = trace_buffer_lock_reserve(tr, TRACE_USER_STACK, sizeof(*entry), flags, pc); if (!event) return; entry = ring_buffer_event_data(event); 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); #endif } #ifdef UNUSED static void __trace_userstack(struct trace_array *tr, unsigned long flags) { ftrace_trace_userstack(tr, flags, preempt_count()); } #endif /* UNUSED */ static void ftrace_trace_special(void *__tr, unsigned long arg1, unsigned long arg2, unsigned long arg3, int pc) { struct ring_buffer_event *event; struct trace_array *tr = __tr; struct special_entry *entry; event = trace_buffer_lock_reserve(tr, TRACE_SPECIAL, sizeof(*entry), 0, pc); if (!event) return; entry = ring_buffer_event_data(event); entry->arg1 = arg1; entry->arg2 = arg2; entry->arg3 = arg3; trace_buffer_unlock_commit(tr, event, 0, pc); } void __trace_special(void *__tr, void *__data, unsigned long arg1, unsigned long arg2, unsigned long arg3) { ftrace_trace_special(__tr, arg1, arg2, arg3, preempt_count()); } void tracing_sched_switch_trace(struct trace_array *tr, struct task_struct *prev, struct task_struct *next, unsigned long flags, int pc) { struct ring_buffer_event *event; struct ctx_switch_entry *entry; event = trace_buffer_lock_reserve(tr, TRACE_CTX, sizeof(*entry), flags, pc); if (!event) return; entry = ring_buffer_event_data(event); 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); trace_buffer_unlock_commit(tr, event, flags, pc); } void tracing_sched_wakeup_trace(struct trace_array *tr, struct task_struct *wakee, struct task_struct *curr, unsigned long flags, int pc) { struct ring_buffer_event *event; struct ctx_switch_entry *entry; event = trace_buffer_lock_reserve(tr, TRACE_WAKE, sizeof(*entry), flags, pc); if (!event) return; entry = ring_buffer_event_data(event); 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); ftrace_trace_stack(tr, flags, 6, pc); ftrace_trace_userstack(tr, flags, pc); } 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, 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 ret; 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(); ret = __trace_graph_entry(tr, trace, flags, pc); } else { ret = 0; } /* 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 ret; } 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, trace, flags, pc); } if (!trace->depth) clear_tsk_trace_graph(current); atomic_dec(&data->disabled); local_irq_restore(flags); } #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ /** * trace_vbprintk - write binary msg to tracing buffer * */ int trace_vbprintk(unsigned long ip, const char *fmt, va_list args) { static raw_spinlock_t trace_buf_lock = (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED; static u32 trace_buf[TRACE_BUF_SIZE]; struct ring_buffer_event *event; struct trace_array *tr = &global_trace; struct trace_array_cpu *data; struct bprint_entry *entry; unsigned long flags; int resched; int cpu, len = 0, size, pc; if (unlikely(tracing_selftest_running || tracing_disabled)) return 0; /* Don't pollute graph traces with trace_vprintk internals */ pause_graph_tracing(); pc = preempt_count(); resched = ftrace_preempt_disable(); cpu = raw_smp_processor_id(); data = tr->data[cpu]; if (unlikely(atomic_read(&data->disabled))) goto out; /* Lockdep uses trace_printk for lock tracing */ local_irq_save(flags); __raw_spin_lock(&trace_buf_lock); len = vbin_printf(trace_buf, TRACE_BUF_SIZE, fmt, args); if (len > TRACE_BUF_SIZE || len < 0) goto out_unlock; size = sizeof(*entry) + sizeof(u32) * len; event = trace_buffer_lock_reserve(tr, TRACE_BPRINT, size, flags, pc); if (!event) goto out_unlock; entry = ring_buffer_event_data(event); entry->ip = ip; entry->fmt = fmt; memcpy(entry->buf, trace_buf, sizeof(u32) * len); ring_buffer_unlock_commit(tr->buffer, event); out_unlock: __raw_spin_unlock(&trace_buf_lock); local_irq_restore(flags); out: ftrace_preempt_enable(resched); unpause_graph_tracing(); return len; } EXPORT_SYMBOL_GPL(trace_vbprintk); int trace_vprintk(unsigned long ip, const char *fmt, va_list args) { static raw_spinlock_t trace_buf_lock = __RAW_SPIN_LOCK_UNLOCKED; 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(); raw_local_irq_save(irq_flags); __raw_spin_lock(&trace_buf_lock); 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 = trace_buffer_lock_reserve(tr, TRACE_PRINT, size, irq_flags, pc); if (!event) goto out_unlock; entry = ring_buffer_event_data(event); entry->ip = ip; memcpy(&entry->buf, trace_buf, len); entry->buf[len] = 0; ring_buffer_unlock_commit(tr->buffer, event); out_unlock: __raw_spin_unlock(&trace_buf_lock); raw_local_irq_restore(irq_flags); unpause_graph_tracing(); out: preempt_enable_notrace(); return len; } EXPORT_SYMBOL_GPL(trace_vprintk); 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; int cpu_file = iter->cpu_file; u64 next_ts = 0, ts; int next_cpu = -1; int cpu; /* * If we are in a per_cpu trace file, don't bother by iterating over * all cpu and peek directly. */ if (cpu_file > TRACE_PIPE_ALL_CPU) { if (ring_buffer_empty_cpu(buffer, cpu_file)) return NULL; ent = peek_next_entry(iter, cpu_file, ent_ts); if (ent_cpu) *ent_cpu = cpu_file; return ent; } 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 */ struct trace_entry *trace_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; } /* * No necessary locking here. The worst thing which can * happen is loosing events consumed at the same time * by a trace_pipe reader. * Other than that, we don't risk to crash the ring buffer * because it serializes the readers. * * The current tracer is copied to avoid a global locking * all around. */ static void *s_start(struct seq_file *m, loff_t *pos) { struct trace_iterator *iter = m->private; static struct tracer *old_tracer; int cpu_file = iter->cpu_file; void *p = NULL; loff_t l = 0; int cpu; /* copy the tracer to avoid using a global lock all around */ mutex_lock(&trace_types_lock); if (unlikely(old_tracer != current_trace && current_trace)) { old_tracer = current_trace; *iter->trace = *current_trace; } mutex_unlock(&trace_types_lock); atomic_inc(&trace_record_cmdline_disabled); if (*pos != iter->pos) { iter->ent = NULL; iter->cpu = 0; iter->idx = -1; ftrace_disable_cpu(); if (cpu_file == TRACE_PIPE_ALL_CPU) { for_each_tracing_cpu(cpu) ring_buffer_iter_reset(iter->buffer_iter[cpu]); } else ring_buffer_iter_reset(iter->buffer_iter[cpu_file]); 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); } 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 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_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; entry = iter->ent; test_cpu_buff_start(iter); event = ftrace_find_event(entry->type); if (trace_flags & TRACE_ITER_CONTEXT_INFO) { if (iter->iter_flags & TRACE_FILE_LAT_FMT) { if (!trace_print_lat_context(iter)) goto partial; } else { if (!trace_print_context(iter)) goto partial; } } if (event) return event->trace(iter, sym_flags); if (!trace_seq_printf(s, "Unknown type %d\n", entry->type)) goto partial; return TRACE_TYPE_HANDLED; partial: return TRACE_TYPE_PARTIAL_LINE; } 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; entry = iter->ent; if (trace_flags & TRACE_ITER_CONTEXT_INFO) { if (!trace_seq_printf(s, "%d %d %llu ", entry->pid, iter->cpu, iter->ts)) goto partial; } event = ftrace_find_event(entry->type); if (event) return event->raw(iter, 0); if (!trace_seq_printf(s, "%d ?\n", entry->type)) goto partial; return TRACE_TYPE_HANDLED; partial: return TRACE_TYPE_PARTIAL_LINE; } 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; if (trace_flags & TRACE_ITER_CONTEXT_INFO) { 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) { enum print_line_t ret = event->hex(iter, 0); if (ret != TRACE_TYPE_HANDLED) return ret; } SEQ_PUT_FIELD_RET(s, newline); 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; if (trace_flags & TRACE_ITER_CONTEXT_INFO) { SEQ_PUT_FIELD_RET(s, entry->pid); SEQ_PUT_FIELD_RET(s, iter->cpu); SEQ_PUT_FIELD_RET(s, iter->ts); } event = ftrace_find_event(entry->type); return event ? event->binary(iter, 0) : TRACE_TYPE_HANDLED; } static int trace_empty(struct trace_iterator *iter) { int cpu; /* If we are looking at one CPU buffer, only check that one */ if (iter->cpu_file != TRACE_PIPE_ALL_CPU) { cpu = iter->cpu_file; 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; } 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_BPRINT && trace_flags & TRACE_ITER_PRINTK && trace_flags & TRACE_ITER_PRINTK_MSGONLY) return trace_print_bprintk_msg_only(iter); if (iter->ent->type == TRACE_PRINT && trace_flags & TRACE_ITER_PRINTK && trace_flags & TRACE_ITER_PRINTK_MSGONLY) return trace_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); 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) { long cpu_file = (long) inode->i_private; void *fail_ret = ERR_PTR(-ENOMEM); struct trace_iterator *iter; struct seq_file *m; int cpu, ret; if (tracing_disabled) return ERR_PTR(-ENODEV); iter = kzalloc(sizeof(*iter), GFP_KERNEL); if (!iter) return ERR_PTR(-ENOMEM); /* * We make a copy of the current tracer to avoid concurrent * changes on it while we are reading. */ mutex_lock(&trace_types_lock); iter->trace = kzalloc(sizeof(*iter->trace), GFP_KERNEL); if (!iter->trace) goto fail; if (current_trace) *iter->trace = *current_trace; if (current_trace && current_trace->print_max) iter->tr = &max_tr; else iter->tr = &global_trace; iter->pos = -1; mutex_init(&iter->mutex); iter->cpu_file = cpu_file; /* 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; if (iter->cpu_file == TRACE_PIPE_ALL_CPU) { for_each_tracing_cpu(cpu) { iter->buffer_iter[cpu] = ring_buffer_read_start(iter->tr->buffer, cpu); } } else { cpu = iter->cpu_file; iter->buffer_iter[cpu] = ring_buffer_read_start(iter->tr->buffer, cpu); } /* TODO stop tracer */ ret = seq_open(file, &tracer_seq_ops); if (ret < 0) { fail_ret = ERR_PTR(ret); goto fail_buffer; } m = file->private_data; m->private = iter; /* stop the trace while dumping */ tracing_stop(); mutex_unlock(&trace_types_lock); return iter; fail_buffer: for_each_tracing_cpu(cpu) { if (iter->buffer_iter[cpu]) ring_buffer_read_finish(iter->buffer_iter[cpu]); } fail: mutex_unlock(&trace_types_lock); kfree(iter->trace); kfree(iter); return fail_ret; } int tracing_open_generic(struct inode *inode, struct file *filp) { if (tracing_disabled) return -ENODEV; filp->private_data = inode->i_private; return 0; } static int tracing_release(struct inode *inode, struct file *file) { struct seq_file *m = (struct seq_file *)file->private_data; struct trace_iterator *iter; int cpu; if (!(file->f_mode & FMODE_READ)) return 0; iter = m->private; 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); mutex_destroy(&iter->mutex); kfree(iter->trace); kfree(iter); return 0; } static int tracing_open(struct inode *inode, struct file *file) { struct trace_iterator *iter; int ret = 0; /* If this file was open for write, then erase contents */ if ((file->f_mode & FMODE_WRITE) && !(file->f_flags & O_APPEND)) { long cpu = (long) inode->i_private; if (cpu == TRACE_PIPE_ALL_CPU) tracing_reset_online_cpus(&global_trace); else tracing_reset(&global_trace, cpu); } if (file->f_mode & FMODE_READ) { iter = __tracing_open(inode, file); if (IS_ERR(iter)) ret = PTR_ERR(iter); else if (trace_flags & TRACE_ITER_LATENCY_FMT) 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 ssize_t tracing_write_stub(struct file *filp, const char __user *ubuf, size_t count, loff_t *ppos) { return count; } static const struct file_operations tracing_fops = { .open = tracing_open, .read = seq_read, .write = tracing_write_stub, .llseek = seq_lseek, .release = tracing_release, }; static const 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 const 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) { struct tracer_opt *trace_opts; u32 tracer_flags; int len = 0; char *buf; int r = 0; int i; /* calculate max size */ for (i = 0; trace_options[i]; i++) { len += strlen(trace_options[i]); len += 3; /* "no" and newline */ } mutex_lock(&trace_types_lock); tracer_flags = current_trace->flags->val; trace_opts = current_trace->flags->opts; /* * 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 newline */ } /* +2 for \n and \0 */ buf = kmalloc(len + 2, GFP_KERNEL); if (!buf) { mutex_unlock(&trace_types_lock); return -ENOMEM; } for (i = 0; trace_options[i]; i++) { if (trace_flags & (1 << i)) r += sprintf(buf + r, "%s\n", trace_options[i]); else r += sprintf(buf + r, "no%s\n", trace_options[i]); } for (i = 0; trace_opts[i].name; i++) { if (tracer_flags & trace_opts[i].bit) r += sprintf(buf + r, "%s\n", trace_opts[i].name); else r += sprintf(buf + r, "no%s\n", trace_opts[i].name); } mutex_unlock(&trace_types_lock); 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 void set_tracer_flags(unsigned int mask, int enabled) { /* do nothing if flag is already set */ if (!!(trace_flags & mask) == !!enabled) return; if (enabled) trace_flags |= mask; else trace_flags &= ~mask; if (mask == TRACE_ITER_GLOBAL_CLK) { u64 (*func)(void); if (enabled) func = trace_clock_global; else func = trace_clock_local; mutex_lock(&trace_types_lock); ring_buffer_set_clock(global_trace.buffer, func); if (max_tr.buffer) ring_buffer_set_clock(max_tr.buffer, func); mutex_unlock(&trace_types_lock); } } 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) { set_tracer_flags(1 << i, !neg); break; } } /* If no option could be set, test the specific tracer options */ if (!trace_options[i]) { mutex_lock(&trace_types_lock); ret = set_tracer_option(current_trace, cmp, neg); mutex_unlock(&trace_types_lock); if (ret) return ret; } filp->f_pos += cnt; return cnt; } static const 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 const 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]; unsigned 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); } int tracer_init(struct tracer *t, struct trace_array *tr) { tracing_reset_online_cpus(tr); return t->init(tr); } static int tracing_resize_ring_buffer(unsigned long size) { int ret; /* * If kernel or user changes the size of the ring buffer * we use the size that was given, and we can forget about * expanding it later. */ ring_buffer_expanded = 1; ret = ring_buffer_resize(global_trace.buffer, size); if (ret < 0) return ret; ret = ring_buffer_resize(max_tr.buffer, size); if (ret < 0) { int r; r = ring_buffer_resize(global_trace.buffer, global_trace.entries); if (r < 0) { /* * AARGH! We are left with different * size max buffer!!!! * The max buffer is our "snapshot" buffer. * When a tracer needs a snapshot (one of the * latency tracers), it swaps the max buffer * with the saved snap shot. We succeeded to * update the size of the main buffer, but failed to * update the size of the max buffer. But when we tried * to reset the main buffer to the original size, we * failed there too. This is very unlikely to * happen, but if it does, warn and kill all * tracing. */ WARN_ON(1); tracing_disabled = 1; } return ret; } global_trace.entries = size; return ret; } /** * tracing_update_buffers - used by tracing facility to expand ring buffers * * To save on memory when the tracing is never used on a system with it * configured in. The ring buffers are set to a minimum size. But once * a user starts to use the tracing facility, then they need to grow * to their default size. * * This function is to be called when a tracer is about to be used. */ int tracing_update_buffers(void) { int ret = 0; mutex_lock(&trace_types_lock); if (!ring_buffer_expanded) ret = tracing_resize_ring_buffer(trace_buf_size); mutex_unlock(&trace_types_lock); return ret; } struct trace_option_dentry; static struct trace_option_dentry * create_trace_option_files(struct tracer *tracer); static void destroy_trace_option_files(struct trace_option_dentry *topts); static int tracing_set_tracer(const char *buf) { static struct trace_option_dentry *topts; struct trace_array *tr = &global_trace; struct tracer *t; int ret = 0; mutex_lock(&trace_types_lock); if (!ring_buffer_expanded) { ret = tracing_resize_ring_buffer(trace_buf_size); if (ret < 0) goto out; ret = 0; } 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); destroy_trace_option_files(topts); current_trace = t; topts = create_trace_option_files(current_trace); if (t->init) { ret = tracer_init(t, 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) { unsigned long *ptr = filp->private_data; char buf[64]; unsigned 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 int tracing_open_pipe(struct inode *inode, struct file *filp) { long cpu_file = (long) inode->i_private; struct trace_iterator *iter; int ret = 0; if (tracing_disabled) return -ENODEV; mutex_lock(&trace_types_lock); /* We only allow one reader per cpu */ if (cpu_file == TRACE_PIPE_ALL_CPU) { if (!cpumask_empty(tracing_reader_cpumask)) { ret = -EBUSY; goto out; } cpumask_setall(tracing_reader_cpumask); } else { if (!cpumask_test_cpu(cpu_file, tracing_reader_cpumask)) cpumask_set_cpu(cpu_file, tracing_reader_cpumask); else { ret = -EBUSY; goto out; } } /* create a buffer to store the information to pass to userspace */ iter = kzalloc(sizeof(*iter), GFP_KERNEL); if (!iter) { ret = -ENOMEM; goto out; } /* * We make a copy of the current tracer to avoid concurrent * changes on it while we are reading. */ iter->trace = kmalloc(sizeof(*iter->trace), GFP_KERNEL); if (!iter->trace) { ret = -ENOMEM; goto fail; } if (current_trace) *iter->trace = *current_trace; if (!alloc_cpumask_var(&iter->started, GFP_KERNEL)) { ret = -ENOMEM; goto fail; } /* trace pipe does not show start of buffer */ cpumask_setall(iter->started); iter->cpu_file = cpu_file; iter->tr = &global_trace; mutex_init(&iter->mutex); filp->private_data = iter; if (iter->trace->pipe_open) iter->trace->pipe_open(iter); out: mutex_unlock(&trace_types_lock); return ret; fail: kfree(iter->trace); kfree(iter); mutex_unlock(&trace_types_lock); return ret; } static int tracing_release_pipe(struct inode *inode, struct file *file) { struct trace_iterator *iter = file->private_data; mutex_lock(&trace_types_lock); if (iter->cpu_file == TRACE_PIPE_ALL_CPU) cpumask_clear(tracing_reader_cpumask); else cpumask_clear_cpu(iter->cpu_file, tracing_reader_cpumask); mutex_unlock(&trace_types_lock); free_cpumask_var(iter->started); mutex_destroy(&iter->mutex); kfree(iter->trace); kfree(iter); 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; } } void default_wait_pipe(struct trace_iterator *iter) { DEFINE_WAIT(wait); prepare_to_wait(&trace_wait, &wait, TASK_INTERRUPTIBLE); if (trace_empty(iter)) schedule(); finish_wait(&trace_wait, &wait); } /* * This is a make-shift waitqueue. * A tracer might use this callback on some rare cases: * * 1) the current tracer might hold the runqueue lock when it wakes up * a reader, hence a deadlock (sched, function, and function graph tracers) * 2) the function tracers, trace 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. */ void poll_wait_pipe(struct trace_iterator *iter) { set_current_state(TASK_INTERRUPTIBLE); /* sleep for 100 msecs, and try again. */ schedule_timeout(HZ / 10); } /* Must be called with trace_types_lock mutex held. */ static int tracing_wait_pipe(struct file *filp) { struct trace_iterator *iter = filp->private_data; while (trace_empty(iter)) { if ((filp->f_flags & O_NONBLOCK)) { return -EAGAIN; } mutex_unlock(&iter->mutex); iter->trace->wait_pipe(iter); mutex_lock(&iter->mutex); if (signal_pending(current)) return -EINTR; /* * 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; } return 1; } /* * 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; static struct tracer *old_tracer; ssize_t sret; /* return any leftover data */ sret = trace_seq_to_user(&iter->seq, ubuf, cnt); if (sret != -EBUSY) return sret; trace_seq_init(&iter->seq); /* copy the tracer to avoid using a global lock all around */ mutex_lock(&trace_types_lock); if (unlikely(old_tracer != current_trace && current_trace)) { old_tracer = current_trace; *iter->trace = *current_trace; } mutex_unlock(&trace_types_lock); /* * Avoid more than one consumer on a single file descriptor * This is just a matter of traces coherency, the ring buffer itself * is protected. */ mutex_lock(&iter->mutex); if (iter->trace->read) { sret = iter->trace->read(iter, filp, ubuf, cnt, ppos); if (sret) goto out; } waitagain: sret = tracing_wait_pipe(filp); if (sret <= 0) goto out; /* stop when tracing is finished */ if (trace_empty(iter)) { sret = 0; 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; } if (ret != TRACE_TYPE_NO_CONSUME) 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_init(&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(&iter->mutex); return sret; } static void tracing_pipe_buf_release(struct pipe_inode_info *pipe, struct pipe_buffer *buf) { __free_page(buf->page); } static void tracing_spd_release_pipe(struct splice_pipe_desc *spd, unsigned int idx) { __free_page(spd->pages[idx]); } static struct pipe_buf_operations tracing_pipe_buf_ops = { .can_merge = 0, .map = generic_pipe_buf_map, .unmap = generic_pipe_buf_unmap, .confirm = generic_pipe_buf_confirm, .release = tracing_pipe_buf_release, .steal = generic_pipe_buf_steal, .get = generic_pipe_buf_get, }; static size_t tracing_fill_pipe_page(size_t rem, struct trace_iterator *iter) { size_t count; int ret; /* Seq buffer is page-sized, exactly what we need. */ for (;;) { count = iter->seq.len; ret = print_trace_line(iter); count = iter->seq.len - count; if (rem < count) { rem = 0; iter->seq.len -= count; break; } if (ret == TRACE_TYPE_PARTIAL_LINE) { iter->seq.len -= count; break; } trace_consume(iter); rem -= count; if (!find_next_entry_inc(iter)) { rem = 0; iter->ent = NULL; break; } } return rem; } static ssize_t tracing_splice_read_pipe(struct file *filp, loff_t *ppos, struct pipe_inode_info *pipe, size_t len, unsigned int flags) { struct page *pages[PIPE_BUFFERS]; struct partial_page partial[PIPE_BUFFERS]; struct trace_iterator *iter = filp->private_data; struct splice_pipe_desc spd = { .pages = pages, .partial = partial, .nr_pages = 0, /* This gets updated below. */ .flags = flags, .ops = &tracing_pipe_buf_ops, .spd_release = tracing_spd_release_pipe, }; static struct tracer *old_tracer; ssize_t ret; size_t rem; unsigned int i; /* copy the tracer to avoid using a global lock all around */ mutex_lock(&trace_types_lock); if (unlikely(old_tracer != current_trace && current_trace)) { old_tracer = current_trace; *iter->trace = *current_trace; } mutex_unlock(&trace_types_lock); mutex_lock(&iter->mutex); if (iter->trace->splice_read) { ret = iter->trace->splice_read(iter, filp, ppos, pipe, len, flags); if (ret) goto out_err; } ret = tracing_wait_pipe(filp); if (ret <= 0) goto out_err; if (!iter->ent && !find_next_entry_inc(iter)) { ret = -EFAULT; goto out_err; } /* Fill as many pages as possible. */ for (i = 0, rem = len; i < PIPE_BUFFERS && rem; i++) { pages[i] = alloc_page(GFP_KERNEL); if (!pages[i]) break; rem = tracing_fill_pipe_page(rem, iter); /* Copy the data into the page, so we can start over. */ ret = trace_seq_to_buffer(&iter->seq, page_address(pages[i]), iter->seq.len); if (ret < 0) { __free_page(pages[i]); break; } partial[i].offset = 0; partial[i].len = iter->seq.len; trace_seq_init(&iter->seq); } mutex_unlock(&iter->mutex); spd.nr_pages = i; return splice_to_pipe(pipe, &spd); out_err: mutex_unlock(&iter->mutex); return ret; } 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[96]; int r; mutex_lock(&trace_types_lock); if (!ring_buffer_expanded) r = sprintf(buf, "%lu (expanded: %lu)\n", tr->entries >> 10, trace_buf_size >> 10); else r = sprintf(buf, "%lu\n", tr->entries >> 10); mutex_unlock(&trace_types_lock); 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 = tracing_resize_ring_buffer(val); if (ret < 0) { cnt = ret; goto out; } } 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, 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 const struct file_operations tracing_max_lat_fops = { .open = tracing_open_generic, .read = tracing_max_lat_read, .write = tracing_max_lat_write, }; static const struct file_operations tracing_ctrl_fops = { .open = tracing_open_generic, .read = tracing_ctrl_read, .write = tracing_ctrl_write, }; static const struct file_operations set_tracer_fops = { .open = tracing_open_generic, .read = tracing_set_trace_read, .write = tracing_set_trace_write, }; static const struct file_operations tracing_pipe_fops = { .open = tracing_open_pipe, .poll = tracing_poll_pipe, .read = tracing_read_pipe, .splice_read = tracing_splice_read_pipe, .release = tracing_release_pipe, }; static const struct file_operations tracing_entries_fops = { .open = tracing_open_generic, .read = tracing_entries_read, .write = tracing_entries_write, }; static const struct file_operations tracing_mark_fops = { .open = tracing_open_generic, .write = tracing_mark_write, }; struct ftrace_buffer_info { struct trace_array *tr; void *spare; int cpu; unsigned int read; }; static int tracing_buffers_open(struct inode *inode, struct file *filp) { int cpu = (int)(long)inode->i_private; struct ftrace_buffer_info *info; if (tracing_disabled) return -ENODEV; info = kzalloc(sizeof(*info), GFP_KERNEL); if (!info) return -ENOMEM; info->tr = &global_trace; info->cpu = cpu; info->spare = ring_buffer_alloc_read_page(info->tr->buffer); /* Force reading ring buffer for first read */ info->read = (unsigned int)-1; if (!info->spare) goto out; filp->private_data = info; return 0; out: kfree(info); return -ENOMEM; } static ssize_t tracing_buffers_read(struct file *filp, char __user *ubuf, size_t count, loff_t *ppos) { struct ftrace_buffer_info *info = filp->private_data; unsigned int pos; ssize_t ret; size_t size; if (!count) return 0; /* Do we have previous read data to read? */ if (info->read < PAGE_SIZE) goto read; info->read = 0; ret = ring_buffer_read_page(info->tr->buffer, &info->spare, count, info->cpu, 0); if (ret < 0) return 0; pos = ring_buffer_page_len(info->spare); if (pos < PAGE_SIZE) memset(info->spare + pos, 0, PAGE_SIZE - pos); read: size = PAGE_SIZE - info->read; if (size > count) size = count; ret = copy_to_user(ubuf, info->spare + info->read, size); if (ret == size) return -EFAULT; size -= ret; *ppos += size; info->read += size; return size; } static int tracing_buffers_release(struct inode *inode, struct file *file) { struct ftrace_buffer_info *info = file->private_data; ring_buffer_free_read_page(info->tr->buffer, info->spare); kfree(info); return 0; } struct buffer_ref { struct ring_buffer *buffer; void *page; int ref; }; static void buffer_pipe_buf_release(struct pipe_inode_info *pipe, struct pipe_buffer *buf) { struct buffer_ref *ref = (struct buffer_ref *)buf->private; if (--ref->ref) return; ring_buffer_free_read_page(ref->buffer, ref->page); kfree(ref); buf->private = 0; } static int buffer_pipe_buf_steal(struct pipe_inode_info *pipe, struct pipe_buffer *buf) { return 1; } static void buffer_pipe_buf_get(struct pipe_inode_info *pipe, struct pipe_buffer *buf) { struct buffer_ref *ref = (struct buffer_ref *)buf->private; ref->ref++; } /* Pipe buffer operations for a buffer. */ static struct pipe_buf_operations buffer_pipe_buf_ops = { .can_merge = 0, .map = generic_pipe_buf_map, .unmap = generic_pipe_buf_unmap, .confirm = generic_pipe_buf_confirm, .release = buffer_pipe_buf_release, .steal = buffer_pipe_buf_steal, .get = buffer_pipe_buf_get, }; /* * Callback from splice_to_pipe(), if we need to release some pages * at the end of the spd in case we error'ed out in filling the pipe. */ static void buffer_spd_release(struct splice_pipe_desc *spd, unsigned int i) { struct buffer_ref *ref = (struct buffer_ref *)spd->partial[i].private; if (--ref->ref) return; ring_buffer_free_read_page(ref->buffer, ref->page); kfree(ref); spd->partial[i].private = 0; } static ssize_t tracing_buffers_splice_read(struct file *file, loff_t *ppos, struct pipe_inode_info *pipe, size_t len, unsigned int flags) { struct ftrace_buffer_info *info = file->private_data; struct partial_page partial[PIPE_BUFFERS]; struct page *pages[PIPE_BUFFERS]; struct splice_pipe_desc spd = { .pages = pages, .partial = partial, .flags = flags, .ops = &buffer_pipe_buf_ops, .spd_release = buffer_spd_release, }; struct buffer_ref *ref; int size, i; size_t ret; /* * We can't seek on a buffer input */ if (unlikely(*ppos)) return -ESPIPE; for (i = 0; i < PIPE_BUFFERS && len; i++, len -= size) { struct page *page; int r; ref = kzalloc(sizeof(*ref), GFP_KERNEL); if (!ref) break; ref->buffer = info->tr->buffer; ref->page = ring_buffer_alloc_read_page(ref->buffer); if (!ref->page) { kfree(ref); break; } r = ring_buffer_read_page(ref->buffer, &ref->page, len, info->cpu, 0); if (r < 0) { ring_buffer_free_read_page(ref->buffer, ref->page); kfree(ref); break; } /* * zero out any left over data, this is going to * user land. */ size = ring_buffer_page_len(ref->page); if (size < PAGE_SIZE) memset(ref->page + size, 0, PAGE_SIZE - size); page = virt_to_page(ref->page); spd.pages[i] = page; spd.partial[i].len = PAGE_SIZE; spd.partial[i].offset = 0; spd.partial[i].private = (unsigned long)ref; spd.nr_pages++; } spd.nr_pages = i; /* did we read anything? */ if (!spd.nr_pages) { if (flags & SPLICE_F_NONBLOCK) ret = -EAGAIN; else ret = 0; /* TODO: block */ return ret; } ret = splice_to_pipe(pipe, &spd); return ret; } static const struct file_operations tracing_buffers_fops = { .open = tracing_buffers_open, .read = tracing_buffers_read, .release = tracing_buffers_release, .splice_read = tracing_buffers_splice_read, .llseek = no_llseek, }; #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 const 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; if (!debugfs_initialized()) return NULL; 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; } static struct dentry *d_percpu; struct dentry *tracing_dentry_percpu(void) { static int once; struct dentry *d_tracer; if (d_percpu) return d_percpu; d_tracer = tracing_init_dentry(); if (!d_tracer) return NULL; d_percpu = debugfs_create_dir("per_cpu", d_tracer); if (!d_percpu && !once) { once = 1; pr_warning("Could not create debugfs directory 'per_cpu'\n"); return NULL; } return d_percpu; } static void tracing_init_debugfs_percpu(long cpu) { struct dentry *d_percpu = tracing_dentry_percpu(); struct dentry *entry, *d_cpu; /* strlen(cpu) + MAX(log10(cpu)) + '\0' */ char cpu_dir[7]; if (cpu > 999 || cpu < 0) return; sprintf(cpu_dir, "cpu%ld", cpu); d_cpu = debugfs_create_dir(cpu_dir, d_percpu); if (!d_cpu) { pr_warning("Could not create debugfs '%s' entry\n", cpu_dir); return; } /* per cpu trace_pipe */ entry = debugfs_create_file("trace_pipe", 0444, d_cpu, (void *) cpu, &tracing_pipe_fops); if (!entry) pr_warning("Could not create debugfs 'trace_pipe' entry\n"); /* per cpu trace */ entry = debugfs_create_file("trace", 0644, d_cpu, (void *) cpu, &tracing_fops); if (!entry) pr_warning("Could not create debugfs 'trace' entry\n"); entry = debugfs_create_file("trace_pipe_raw", 0444, d_cpu, (void *) cpu, &tracing_buffers_fops); if (!entry) pr_warning("Could not create debugfs 'trace_pipe_raw' entry\n"); } #ifdef CONFIG_FTRACE_SELFTEST /* Let selftest have access to static functions in this file */ #include "trace_selftest.c" #endif struct trace_option_dentry { struct tracer_opt *opt; struct tracer_flags *flags; struct dentry *entry; }; static ssize_t trace_options_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos) { struct trace_option_dentry *topt = filp->private_data; char *buf; if (topt->flags->val & topt->opt->bit) buf = "1\n"; else buf = "0\n"; return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2); } static ssize_t trace_options_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *ppos) { struct trace_option_dentry *topt = filp->private_data; unsigned long val; char buf[64]; 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; ret = 0; switch (val) { case 0: /* do nothing if already cleared */ if (!(topt->flags->val & topt->opt->bit)) break; mutex_lock(&trace_types_lock); if (current_trace->set_flag) ret = current_trace->set_flag(topt->flags->val, topt->opt->bit, 0); mutex_unlock(&trace_types_lock); if (ret) return ret; topt->flags->val &= ~topt->opt->bit; break; case 1: /* do nothing if already set */ if (topt->flags->val & topt->opt->bit) break; mutex_lock(&trace_types_lock); if (current_trace->set_flag) ret = current_trace->set_flag(topt->flags->val, topt->opt->bit, 1); mutex_unlock(&trace_types_lock); if (ret) return ret; topt->flags->val |= topt->opt->bit; break; default: return -EINVAL; } *ppos += cnt; return cnt; } static const struct file_operations trace_options_fops = { .open = tracing_open_generic, .read = trace_options_read, .write = trace_options_write, }; static ssize_t trace_options_core_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos) { long index = (long)filp->private_data; char *buf; if (trace_flags & (1 << index)) buf = "1\n"; else buf = "0\n"; return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2); } static ssize_t trace_options_core_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *ppos) { long index = (long)filp->private_data; char buf[64]; unsigned 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; switch (val) { case 0: trace_flags &= ~(1 << index); break; case 1: trace_flags |= 1 << index; break; default: return -EINVAL; } *ppos += cnt; return cnt; } static const struct file_operations trace_options_core_fops = { .open = tracing_open_generic, .read = trace_options_core_read, .write = trace_options_core_write, }; static struct dentry *trace_options_init_dentry(void) { struct dentry *d_tracer; static struct dentry *t_options; if (t_options) return t_options; d_tracer = tracing_init_dentry(); if (!d_tracer) return NULL; t_options = debugfs_create_dir("options", d_tracer); if (!t_options) { pr_warning("Could not create debugfs directory 'options'\n"); return NULL; } return t_options; } static void create_trace_option_file(struct trace_option_dentry *topt, struct tracer_flags *flags, struct tracer_opt *opt) { struct dentry *t_options; struct dentry *entry; t_options = trace_options_init_dentry(); if (!t_options) return; topt->flags = flags; topt->opt = opt; entry = debugfs_create_file(opt->name, 0644, t_options, topt, &trace_options_fops); topt->entry = entry; } static struct trace_option_dentry * create_trace_option_files(struct tracer *tracer) { struct trace_option_dentry *topts; struct tracer_flags *flags; struct tracer_opt *opts; int cnt; if (!tracer) return NULL; flags = tracer->flags; if (!flags || !flags->opts) return NULL; opts = flags->opts; for (cnt = 0; opts[cnt].name; cnt++) ; topts = kcalloc(cnt + 1, sizeof(*topts), GFP_KERNEL); if (!topts) return NULL; for (cnt = 0; opts[cnt].name; cnt++) create_trace_option_file(&topts[cnt], flags, &opts[cnt]); return topts; } static void destroy_trace_option_files(struct trace_option_dentry *topts) { int cnt; if (!topts) return; for (cnt = 0; topts[cnt].opt; cnt++) { if (topts[cnt].entry) debugfs_remove(topts[cnt].entry); } kfree(topts); } static struct dentry * create_trace_option_core_file(const char *option, long index) { struct dentry *t_options; struct dentry *entry; t_options = trace_options_init_dentry(); if (!t_options) return NULL; entry = debugfs_create_file(option, 0644, t_options, (void *)index, &trace_options_core_fops); return entry; } static __init void create_trace_options_dir(void) { struct dentry *t_options; struct dentry *entry; int i; t_options = trace_options_init_dentry(); if (!t_options) return; for (i = 0; trace_options[i]; i++) { entry = create_trace_option_core_file(trace_options[i], i); if (!entry) pr_warning("Could not create debugfs %s entry\n", trace_options[i]); } } static __init int tracer_init_debugfs(void) { struct dentry *d_tracer; struct dentry *entry; int cpu; 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"); create_trace_options_dir(); 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("trace", 0644, d_tracer, (void *) TRACE_PIPE_ALL_CPU, &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", 0444, d_tracer, (void *) TRACE_PIPE_ALL_CPU, &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 for_each_tracing_cpu(cpu) tracing_init_debugfs_percpu(cpu); return 0; } 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_init(s); } static void __ftrace_dump(bool disable_tracing) { static DEFINE_SPINLOCK(ftrace_dump_lock); /* use static because iter can be a bit big for the stack */ static struct trace_iterator iter; unsigned int old_userobj; 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; tracing_off(); if (disable_tracing) ftrace_kill(); for_each_tracing_cpu(cpu) { atomic_inc(&global_trace.data[cpu]->disabled); } old_userobj = trace_flags & TRACE_ITER_SYM_USEROBJ; /* don't look at user memory in panic mode */ trace_flags &= ~TRACE_ITER_SYM_USEROBJ; printk(KERN_TRACE "Dumping ftrace buffer:\n"); /* Simulate the iterator */ iter.tr = &global_trace; iter.trace = current_trace; iter.cpu_file = TRACE_PIPE_ALL_CPU; /* * 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"); /* Re-enable tracing if requested */ if (!disable_tracing) { trace_flags |= old_userobj; for_each_tracing_cpu(cpu) { atomic_dec(&global_trace.data[cpu]->disabled); } tracing_on(); } out: spin_unlock_irqrestore(&ftrace_dump_lock, flags); } /* By default: disable tracing after the dump */ void ftrace_dump(void) { __ftrace_dump(true); } __init static int tracer_alloc_buffers(void) { struct trace_array_cpu *data; int ring_buf_size; 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; if (!alloc_cpumask_var(&tracing_reader_cpumask, GFP_KERNEL)) goto out_free_tracing_cpumask; /* To save memory, keep the ring buffer size to its minimum */ if (ring_buffer_expanded) ring_buf_size = trace_buf_size; else ring_buf_size = 1; cpumask_copy(tracing_buffer_mask, cpu_possible_mask); cpumask_copy(tracing_cpumask, cpu_all_mask); cpumask_clear(tracing_reader_cpumask); /* TODO: make the number of buffers hot pluggable with CPUS */ global_trace.buffer = ring_buffer_alloc(ring_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(ring_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); return 0; out_free_cpumask: free_cpumask_var(tracing_reader_cpumask); out_free_tracing_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);