/* * ring buffer based function tracer * * Copyright (C) 2007-2012 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 Nadia Yvette Chambers */ #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 #include #include #include "trace.h" #include "trace_output.h" /* * 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. */ bool 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. */ 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; } /* * To prevent the comm cache from being overwritten when no * tracing is active, only save the comm when a trace event * occurred. */ static DEFINE_PER_CPU(bool, trace_cmdline_save); /* * 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; DEFINE_PER_CPU(int, ftrace_cpu_disabled); cpumask_var_t __read_mostly 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 * Set 1 if you want to dump buffers of all CPUs * Set 2 if you want to dump the buffer of the CPU that triggered oops */ enum ftrace_dump_mode ftrace_dump_on_oops; static int tracing_set_tracer(const char *buf); #define MAX_TRACER_SIZE 100 static char bootup_tracer_buf[MAX_TRACER_SIZE] __initdata; static char *default_bootup_tracer; static bool allocate_snapshot; static int __init set_cmdline_ftrace(char *str) { strncpy(bootup_tracer_buf, str, MAX_TRACER_SIZE); default_bootup_tracer = bootup_tracer_buf; /* We are using ftrace early, expand it */ ring_buffer_expanded = true; return 1; } __setup("ftrace=", set_cmdline_ftrace); static int __init set_ftrace_dump_on_oops(char *str) { if (*str++ != '=' || !*str) { ftrace_dump_on_oops = DUMP_ALL; return 1; } if (!strcmp("orig_cpu", str)) { ftrace_dump_on_oops = DUMP_ORIG; return 1; } return 0; } __setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops); static int __init boot_alloc_snapshot(char *str) { allocate_snapshot = true; /* We also need the main ring buffer expanded */ ring_buffer_expanded = true; return 1; } __setup("alloc_snapshot", boot_alloc_snapshot); static char trace_boot_options_buf[MAX_TRACER_SIZE] __initdata; static char *trace_boot_options __initdata; static int __init set_trace_boot_options(char *str) { strncpy(trace_boot_options_buf, str, MAX_TRACER_SIZE); trace_boot_options = trace_boot_options_buf; return 0; } __setup("trace_options=", set_trace_boot_options); 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; LIST_HEAD(ftrace_trace_arrays); int filter_current_check_discard(struct ring_buffer *buffer, struct ftrace_event_call *call, void *rec, struct ring_buffer_event *event) { return filter_check_discard(call, rec, buffer, event); } EXPORT_SYMBOL_GPL(filter_current_check_discard); cycle_t ftrace_now(int cpu) { u64 ts; /* Early boot up does not have a buffer yet */ if (!global_trace.trace_buffer.buffer) return trace_clock_local(); ts = ring_buffer_time_stamp(global_trace.trace_buffer.buffer, cpu); ring_buffer_normalize_time_stamp(global_trace.trace_buffer.buffer, cpu, &ts); return ts; } int tracing_is_enabled(void) { return tracing_is_on(); } /* * 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; /* * trace_types_lock is used to protect the trace_types list. */ static DEFINE_MUTEX(trace_types_lock); /* * serialize the access of the ring buffer * * ring buffer serializes readers, but it is low level protection. * The validity of the events (which returns by ring_buffer_peek() ..etc) * are not protected by ring buffer. * * The content of events may become garbage if we allow other process consumes * these events concurrently: * A) the page of the consumed events may become a normal page * (not reader page) in ring buffer, and this page will be rewrited * by events producer. * B) The page of the consumed events may become a page for splice_read, * and this page will be returned to system. * * These primitives allow multi process access to different cpu ring buffer * concurrently. * * These primitives don't distinguish read-only and read-consume access. * Multi read-only access are also serialized. */ #ifdef CONFIG_SMP static DECLARE_RWSEM(all_cpu_access_lock); static DEFINE_PER_CPU(struct mutex, cpu_access_lock); static inline void trace_access_lock(int cpu) { if (cpu == RING_BUFFER_ALL_CPUS) { /* gain it for accessing the whole ring buffer. */ down_write(&all_cpu_access_lock); } else { /* gain it for accessing a cpu ring buffer. */ /* Firstly block other trace_access_lock(RING_BUFFER_ALL_CPUS). */ down_read(&all_cpu_access_lock); /* Secondly block other access to this @cpu ring buffer. */ mutex_lock(&per_cpu(cpu_access_lock, cpu)); } } static inline void trace_access_unlock(int cpu) { if (cpu == RING_BUFFER_ALL_CPUS) { up_write(&all_cpu_access_lock); } else { mutex_unlock(&per_cpu(cpu_access_lock, cpu)); up_read(&all_cpu_access_lock); } } static inline void trace_access_lock_init(void) { int cpu; for_each_possible_cpu(cpu) mutex_init(&per_cpu(cpu_access_lock, cpu)); } #else static DEFINE_MUTEX(access_lock); static inline void trace_access_lock(int cpu) { (void)cpu; mutex_lock(&access_lock); } static inline void trace_access_unlock(int cpu) { (void)cpu; mutex_unlock(&access_lock); } static inline void trace_access_lock_init(void) { } #endif /* 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_ITER_GRAPH_TIME | TRACE_ITER_RECORD_CMD | TRACE_ITER_OVERWRITE | TRACE_ITER_IRQ_INFO | TRACE_ITER_MARKERS; /** * tracing_on - enable tracing buffers * * This function enables tracing buffers that may have been * disabled with tracing_off. */ void tracing_on(void) { if (global_trace.trace_buffer.buffer) ring_buffer_record_on(global_trace.trace_buffer.buffer); /* * This flag is only looked at when buffers haven't been * allocated yet. We don't really care about the race * between setting this flag and actually turning * on the buffer. */ global_trace.buffer_disabled = 0; } EXPORT_SYMBOL_GPL(tracing_on); /** * __trace_puts - write a constant string into the trace buffer. * @ip: The address of the caller * @str: The constant string to write * @size: The size of the string. */ int __trace_puts(unsigned long ip, const char *str, int size) { struct ring_buffer_event *event; struct ring_buffer *buffer; struct print_entry *entry; unsigned long irq_flags; int alloc; alloc = sizeof(*entry) + size + 2; /* possible \n added */ local_save_flags(irq_flags); buffer = global_trace.trace_buffer.buffer; event = trace_buffer_lock_reserve(buffer, TRACE_PRINT, alloc, irq_flags, preempt_count()); if (!event) return 0; entry = ring_buffer_event_data(event); entry->ip = ip; memcpy(&entry->buf, str, size); /* Add a newline if necessary */ if (entry->buf[size - 1] != '\n') { entry->buf[size] = '\n'; entry->buf[size + 1] = '\0'; } else entry->buf[size] = '\0'; __buffer_unlock_commit(buffer, event); return size; } EXPORT_SYMBOL_GPL(__trace_puts); /** * __trace_bputs - write the pointer to a constant string into trace buffer * @ip: The address of the caller * @str: The constant string to write to the buffer to */ int __trace_bputs(unsigned long ip, const char *str) { struct ring_buffer_event *event; struct ring_buffer *buffer; struct bputs_entry *entry; unsigned long irq_flags; int size = sizeof(struct bputs_entry); local_save_flags(irq_flags); buffer = global_trace.trace_buffer.buffer; event = trace_buffer_lock_reserve(buffer, TRACE_BPUTS, size, irq_flags, preempt_count()); if (!event) return 0; entry = ring_buffer_event_data(event); entry->ip = ip; entry->str = str; __buffer_unlock_commit(buffer, event); return 1; } EXPORT_SYMBOL_GPL(__trace_bputs); #ifdef CONFIG_TRACER_SNAPSHOT /** * trace_snapshot - take a snapshot of the current buffer. * * This causes a swap between the snapshot buffer and the current live * tracing buffer. You can use this to take snapshots of the live * trace when some condition is triggered, but continue to trace. * * Note, make sure to allocate the snapshot with either * a tracing_snapshot_alloc(), or by doing it manually * with: echo 1 > /sys/kernel/debug/tracing/snapshot * * If the snapshot buffer is not allocated, it will stop tracing. * Basically making a permanent snapshot. */ void tracing_snapshot(void) { struct trace_array *tr = &global_trace; struct tracer *tracer = tr->current_trace; unsigned long flags; if (in_nmi()) { internal_trace_puts("*** SNAPSHOT CALLED FROM NMI CONTEXT ***\n"); internal_trace_puts("*** snapshot is being ignored ***\n"); return; } if (!tr->allocated_snapshot) { internal_trace_puts("*** SNAPSHOT NOT ALLOCATED ***\n"); internal_trace_puts("*** stopping trace here! ***\n"); tracing_off(); return; } /* Note, snapshot can not be used when the tracer uses it */ if (tracer->use_max_tr) { internal_trace_puts("*** LATENCY TRACER ACTIVE ***\n"); internal_trace_puts("*** Can not use snapshot (sorry) ***\n"); return; } local_irq_save(flags); update_max_tr(tr, current, smp_processor_id()); local_irq_restore(flags); } EXPORT_SYMBOL_GPL(tracing_snapshot); static int resize_buffer_duplicate_size(struct trace_buffer *trace_buf, struct trace_buffer *size_buf, int cpu_id); static void set_buffer_entries(struct trace_buffer *buf, unsigned long val); static int alloc_snapshot(struct trace_array *tr) { int ret; if (!tr->allocated_snapshot) { /* allocate spare buffer */ ret = resize_buffer_duplicate_size(&tr->max_buffer, &tr->trace_buffer, RING_BUFFER_ALL_CPUS); if (ret < 0) return ret; tr->allocated_snapshot = true; } return 0; } void free_snapshot(struct trace_array *tr) { /* * We don't free the ring buffer. instead, resize it because * The max_tr ring buffer has some state (e.g. ring->clock) and * we want preserve it. */ ring_buffer_resize(tr->max_buffer.buffer, 1, RING_BUFFER_ALL_CPUS); set_buffer_entries(&tr->max_buffer, 1); tracing_reset_online_cpus(&tr->max_buffer); tr->allocated_snapshot = false; } /** * trace_snapshot_alloc - allocate and take a snapshot of the current buffer. * * This is similar to trace_snapshot(), but it will allocate the * snapshot buffer if it isn't already allocated. Use this only * where it is safe to sleep, as the allocation may sleep. * * This causes a swap between the snapshot buffer and the current live * tracing buffer. You can use this to take snapshots of the live * trace when some condition is triggered, but continue to trace. */ void tracing_snapshot_alloc(void) { struct trace_array *tr = &global_trace; int ret; ret = alloc_snapshot(tr); if (WARN_ON(ret < 0)) return; tracing_snapshot(); } EXPORT_SYMBOL_GPL(tracing_snapshot_alloc); #else void tracing_snapshot(void) { WARN_ONCE(1, "Snapshot feature not enabled, but internal snapshot used"); } EXPORT_SYMBOL_GPL(tracing_snapshot); void tracing_snapshot_alloc(void) { /* Give warning */ tracing_snapshot(); } EXPORT_SYMBOL_GPL(tracing_snapshot_alloc); #endif /* CONFIG_TRACER_SNAPSHOT */ /** * tracing_off - turn off tracing buffers * * This function stops the tracing buffers from recording data. * It does not disable any overhead the tracers themselves may * be causing. This function simply causes all recording to * the ring buffers to fail. */ void tracing_off(void) { if (global_trace.trace_buffer.buffer) ring_buffer_record_off(global_trace.trace_buffer.buffer); /* * This flag is only looked at when buffers haven't been * allocated yet. We don't really care about the race * between setting this flag and actually turning * on the buffer. */ global_trace.buffer_disabled = 1; } EXPORT_SYMBOL_GPL(tracing_off); /** * tracing_is_on - show state of ring buffers enabled */ int tracing_is_on(void) { if (global_trace.trace_buffer.buffer) return ring_buffer_record_is_on(global_trace.trace_buffer.buffer); return !global_trace.buffer_disabled; } EXPORT_SYMBOL_GPL(tracing_is_on); static int __init set_buf_size(char *str) { unsigned long buf_size; if (!str) return 0; buf_size = memparse(str, &str); /* nr_entries can not be zero */ if (buf_size == 0) return 0; trace_buf_size = buf_size; return 1; } __setup("trace_buf_size=", set_buf_size); static int __init set_tracing_thresh(char *str) { unsigned long threshold; int ret; if (!str) return 0; ret = kstrtoul(str, 0, &threshold); if (ret < 0) return 0; tracing_thresh = threshold * 1000; return 1; } __setup("tracing_thresh=", set_tracing_thresh); 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", "trace_printk", "ftrace_preempt", "branch", "annotate", "userstacktrace", "sym-userobj", "printk-msg-only", "context-info", "latency-format", "sleep-time", "graph-time", "record-cmd", "overwrite", "disable_on_free", "irq-info", "markers", NULL }; static struct { u64 (*func)(void); const char *name; int in_ns; /* is this clock in nanoseconds? */ } trace_clocks[] = { { trace_clock_local, "local", 1 }, { trace_clock_global, "global", 1 }, { trace_clock_counter, "counter", 0 }, ARCH_TRACE_CLOCKS }; int trace_clock_id; /* * trace_parser_get_init - gets the buffer for trace parser */ int trace_parser_get_init(struct trace_parser *parser, int size) { memset(parser, 0, sizeof(*parser)); parser->buffer = kmalloc(size, GFP_KERNEL); if (!parser->buffer) return 1; parser->size = size; return 0; } /* * trace_parser_put - frees the buffer for trace parser */ void trace_parser_put(struct trace_parser *parser) { kfree(parser->buffer); } /* * trace_get_user - reads the user input string separated by space * (matched by isspace(ch)) * * For each string found the 'struct trace_parser' is updated, * and the function returns. * * Returns number of bytes read. * * See kernel/trace/trace.h for 'struct trace_parser' details. */ int trace_get_user(struct trace_parser *parser, const char __user *ubuf, size_t cnt, loff_t *ppos) { char ch; size_t read = 0; ssize_t ret; if (!*ppos) trace_parser_clear(parser); ret = get_user(ch, ubuf++); if (ret) goto out; read++; cnt--; /* * The parser is not finished with the last write, * continue reading the user input without skipping spaces. */ if (!parser->cont) { /* skip white space */ while (cnt && isspace(ch)) { ret = get_user(ch, ubuf++); if (ret) goto out; read++; cnt--; } /* only spaces were written */ if (isspace(ch)) { *ppos += read; ret = read; goto out; } parser->idx = 0; } /* read the non-space input */ while (cnt && !isspace(ch)) { if (parser->idx < parser->size - 1) parser->buffer[parser->idx++] = ch; else { ret = -EINVAL; goto out; } ret = get_user(ch, ubuf++); if (ret) goto out; read++; cnt--; } /* We either got finished input or we have to wait for another call. */ if (isspace(ch)) { parser->buffer[parser->idx] = 0; parser->cont = false; } else { parser->cont = true; parser->buffer[parser->idx++] = ch; } *ppos += read; ret = read; out: return ret; } 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; if (s->len <= s->readpos) return -EBUSY; len = s->len - s->readpos; if (cnt > len) cnt = len; memcpy(buf, s->buffer + s->readpos, cnt); s->readpos += cnt; return cnt; } /* * 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 arch_spinlock_t in order to help * with performance when lockdep debugging is enabled. * * It is also used in other places outside the update_max_tr * so it needs to be defined outside of the * CONFIG_TRACER_MAX_TRACE. */ static arch_spinlock_t ftrace_max_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED; unsigned long __read_mostly tracing_thresh; #ifdef CONFIG_TRACER_MAX_TRACE unsigned long __read_mostly tracing_max_latency; /* * Copy the new maximum trace into the separate maximum-trace * structure. (this way the maximum trace is permanently saved, * for later retrieval via /sys/kernel/debug/tracing/latency_trace) */ static void __update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu) { struct trace_buffer *trace_buf = &tr->trace_buffer; struct trace_buffer *max_buf = &tr->max_buffer; struct trace_array_cpu *data = per_cpu_ptr(trace_buf->data, cpu); struct trace_array_cpu *max_data = per_cpu_ptr(max_buf->data, cpu); max_buf->cpu = cpu; max_buf->time_start = data->preempt_timestamp; max_data->saved_latency = tracing_max_latency; max_data->critical_start = data->critical_start; max_data->critical_end = data->critical_end; memcpy(max_data->comm, tsk->comm, TASK_COMM_LEN); max_data->pid = tsk->pid; max_data->uid = task_uid(tsk); max_data->nice = tsk->static_prio - 20 - MAX_RT_PRIO; max_data->policy = tsk->policy; max_data->rt_priority = tsk->rt_priority; /* record this tasks comm */ tracing_record_cmdline(tsk); } /** * 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; if (tr->stop_count) return; WARN_ON_ONCE(!irqs_disabled()); if (!tr->allocated_snapshot) { /* Only the nop tracer should hit this when disabling */ WARN_ON_ONCE(tr->current_trace != &nop_trace); return; } arch_spin_lock(&ftrace_max_lock); buf = tr->trace_buffer.buffer; tr->trace_buffer.buffer = tr->max_buffer.buffer; tr->max_buffer.buffer = buf; __update_max_tr(tr, tsk, cpu); arch_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; if (tr->stop_count) return; WARN_ON_ONCE(!irqs_disabled()); if (WARN_ON_ONCE(!tr->allocated_snapshot)) return; arch_spin_lock(&ftrace_max_lock); ret = ring_buffer_swap_cpu(tr->max_buffer.buffer, tr->trace_buffer.buffer, cpu); if (ret == -EBUSY) { /* * We failed to swap the buffer due to a commit taking * place on this CPU. We fail to record, but we reset * the max trace buffer (no one writes directly to it) * and flag that it failed. */ trace_array_printk_buf(tr->max_buffer.buffer, _THIS_IP_, "Failed to swap buffers due to commit in progress\n"); } WARN_ON_ONCE(ret && ret != -EAGAIN && ret != -EBUSY); __update_max_tr(tr, tsk, cpu); arch_spin_unlock(&ftrace_max_lock); } #endif /* CONFIG_TRACER_MAX_TRACE */ static void default_wait_pipe(struct trace_iterator *iter) { /* Iterators are static, they should be filled or empty */ if (trace_buffer_iter(iter, iter->cpu_file)) return; ring_buffer_wait(iter->trace_buffer->buffer, iter->cpu_file); } #ifdef CONFIG_FTRACE_STARTUP_TEST static int run_tracer_selftest(struct tracer *type) { struct trace_array *tr = &global_trace; struct tracer *saved_tracer = tr->current_trace; int ret; if (!type->selftest || tracing_selftest_disabled) return 0; /* * 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. */ tracing_reset_online_cpus(&tr->trace_buffer); tr->current_trace = type; #ifdef CONFIG_TRACER_MAX_TRACE if (type->use_max_tr) { /* If we expanded the buffers, make sure the max is expanded too */ if (ring_buffer_expanded) ring_buffer_resize(tr->max_buffer.buffer, trace_buf_size, RING_BUFFER_ALL_CPUS); tr->allocated_snapshot = true; } #endif /* 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 */ tr->current_trace = saved_tracer; if (ret) { printk(KERN_CONT "FAILED!\n"); /* Add the warning after printing 'FAILED' */ WARN_ON(1); return -1; } /* Only reset on passing, to avoid touching corrupted buffers */ tracing_reset_online_cpus(&tr->trace_buffer); #ifdef CONFIG_TRACER_MAX_TRACE if (type->use_max_tr) { tr->allocated_snapshot = false; /* Shrink the max buffer again */ if (ring_buffer_expanded) ring_buffer_resize(tr->max_buffer.buffer, 1, RING_BUFFER_ALL_CPUS); } #endif printk(KERN_CONT "PASSED\n"); return 0; } #else static inline int run_tracer_selftest(struct tracer *type) { return 0; } #endif /* CONFIG_FTRACE_STARTUP_TEST */ /** * 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 ret = 0; if (!type->name) { pr_info("Tracer must have a name\n"); return -1; } if (strlen(type->name) >= MAX_TRACER_SIZE) { pr_info("Tracer has a name longer than %d\n", MAX_TRACER_SIZE); return -1; } 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("Tracer %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; ret = run_tracer_selftest(type); if (ret < 0) goto out; type->next = trace_types; trace_types = type; 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, MAX_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 = true; #ifdef CONFIG_FTRACE_STARTUP_TEST printk(KERN_INFO "Disabling FTRACE selftests due to running tracer '%s'\n", type->name); #endif out_unlock: return ret; } void tracing_reset(struct trace_buffer *buf, int cpu) { struct ring_buffer *buffer = buf->buffer; if (!buffer) return; ring_buffer_record_disable(buffer); /* Make sure all commits have finished */ synchronize_sched(); ring_buffer_reset_cpu(buffer, cpu); ring_buffer_record_enable(buffer); } void tracing_reset_online_cpus(struct trace_buffer *buf) { struct ring_buffer *buffer = buf->buffer; int cpu; if (!buffer) return; ring_buffer_record_disable(buffer); /* Make sure all commits have finished */ synchronize_sched(); buf->time_start = ftrace_now(buf->cpu); for_each_online_cpu(cpu) ring_buffer_reset_cpu(buffer, cpu); ring_buffer_record_enable(buffer); } void tracing_reset_current(int cpu) { tracing_reset(&global_trace.trace_buffer, cpu); } void tracing_reset_all_online_cpus(void) { struct trace_array *tr; mutex_lock(&trace_types_lock); list_for_each_entry(tr, &ftrace_trace_arrays, list) { tracing_reset_online_cpus(&tr->trace_buffer); #ifdef CONFIG_TRACER_MAX_TRACE tracing_reset_online_cpus(&tr->max_buffer); #endif } mutex_unlock(&trace_types_lock); } #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 arch_spinlock_t trace_cmdline_lock = __ARCH_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; } int is_tracing_stopped(void) { return global_trace.stop_count; } /** * 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; raw_spin_lock_irqsave(&global_trace.start_lock, flags); if (--global_trace.stop_count) { if (global_trace.stop_count < 0) { /* Someone screwed up their debugging */ WARN_ON_ONCE(1); global_trace.stop_count = 0; } goto out; } /* Prevent the buffers from switching */ arch_spin_lock(&ftrace_max_lock); buffer = global_trace.trace_buffer.buffer; if (buffer) ring_buffer_record_enable(buffer); #ifdef CONFIG_TRACER_MAX_TRACE buffer = global_trace.max_buffer.buffer; if (buffer) ring_buffer_record_enable(buffer); #endif arch_spin_unlock(&ftrace_max_lock); ftrace_start(); out: raw_spin_unlock_irqrestore(&global_trace.start_lock, flags); } static void tracing_start_tr(struct trace_array *tr) { struct ring_buffer *buffer; unsigned long flags; if (tracing_disabled) return; /* If global, we need to also start the max tracer */ if (tr->flags & TRACE_ARRAY_FL_GLOBAL) return tracing_start(); raw_spin_lock_irqsave(&tr->start_lock, flags); if (--tr->stop_count) { if (tr->stop_count < 0) { /* Someone screwed up their debugging */ WARN_ON_ONCE(1); tr->stop_count = 0; } goto out; } buffer = tr->trace_buffer.buffer; if (buffer) ring_buffer_record_enable(buffer); out: raw_spin_unlock_irqrestore(&tr->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(); raw_spin_lock_irqsave(&global_trace.start_lock, flags); if (global_trace.stop_count++) goto out; /* Prevent the buffers from switching */ arch_spin_lock(&ftrace_max_lock); buffer = global_trace.trace_buffer.buffer; if (buffer) ring_buffer_record_disable(buffer); #ifdef CONFIG_TRACER_MAX_TRACE buffer = global_trace.max_buffer.buffer; if (buffer) ring_buffer_record_disable(buffer); #endif arch_spin_unlock(&ftrace_max_lock); out: raw_spin_unlock_irqrestore(&global_trace.start_lock, flags); } static void tracing_stop_tr(struct trace_array *tr) { struct ring_buffer *buffer; unsigned long flags; /* If global, we need to also stop the max tracer */ if (tr->flags & TRACE_ARRAY_FL_GLOBAL) return tracing_stop(); raw_spin_lock_irqsave(&tr->start_lock, flags); if (tr->stop_count++) goto out; buffer = tr->trace_buffer.buffer; if (buffer) ring_buffer_record_disable(buffer); out: raw_spin_unlock_irqrestore(&tr->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 (!arch_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); arch_spin_unlock(&trace_cmdline_lock); } void trace_find_cmdline(int pid, char comm[]) { unsigned map; if (!pid) { strcpy(comm, ""); return; } if (WARN_ON_ONCE(pid < 0)) { strcpy(comm, ""); return; } if (pid > PID_MAX_DEFAULT) { strcpy(comm, "<...>"); return; } preempt_disable(); arch_spin_lock(&trace_cmdline_lock); map = map_pid_to_cmdline[pid]; if (map != NO_CMDLINE_MAP) strcpy(comm, saved_cmdlines[map]); else strcpy(comm, "<...>"); arch_spin_unlock(&trace_cmdline_lock); preempt_enable(); } void tracing_record_cmdline(struct task_struct *tsk) { if (atomic_read(&trace_record_cmdline_disabled) || !tracing_is_on()) return; if (!__this_cpu_read(trace_cmdline_save)) return; __this_cpu_write(trace_cmdline_save, false); 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->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); } EXPORT_SYMBOL_GPL(tracing_generic_entry_update); struct ring_buffer_event * trace_buffer_lock_reserve(struct ring_buffer *buffer, int type, unsigned long len, unsigned long flags, int pc) { struct ring_buffer_event *event; event = ring_buffer_lock_reserve(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; } void __buffer_unlock_commit(struct ring_buffer *buffer, struct ring_buffer_event *event) { __this_cpu_write(trace_cmdline_save, true); ring_buffer_unlock_commit(buffer, event); } static inline void __trace_buffer_unlock_commit(struct ring_buffer *buffer, struct ring_buffer_event *event, unsigned long flags, int pc) { __buffer_unlock_commit(buffer, event); ftrace_trace_stack(buffer, flags, 6, pc); ftrace_trace_userstack(buffer, flags, pc); } void trace_buffer_unlock_commit(struct ring_buffer *buffer, struct ring_buffer_event *event, unsigned long flags, int pc) { __trace_buffer_unlock_commit(buffer, event, flags, pc); } EXPORT_SYMBOL_GPL(trace_buffer_unlock_commit); struct ring_buffer_event * trace_event_buffer_lock_reserve(struct ring_buffer **current_rb, struct ftrace_event_file *ftrace_file, int type, unsigned long len, unsigned long flags, int pc) { *current_rb = ftrace_file->tr->trace_buffer.buffer; return trace_buffer_lock_reserve(*current_rb, type, len, flags, pc); } EXPORT_SYMBOL_GPL(trace_event_buffer_lock_reserve); struct ring_buffer_event * trace_current_buffer_lock_reserve(struct ring_buffer **current_rb, int type, unsigned long len, unsigned long flags, int pc) { *current_rb = global_trace.trace_buffer.buffer; return trace_buffer_lock_reserve(*current_rb, type, len, flags, pc); } EXPORT_SYMBOL_GPL(trace_current_buffer_lock_reserve); void trace_current_buffer_unlock_commit(struct ring_buffer *buffer, struct ring_buffer_event *event, unsigned long flags, int pc) { __trace_buffer_unlock_commit(buffer, event, flags, pc); } EXPORT_SYMBOL_GPL(trace_current_buffer_unlock_commit); void trace_buffer_unlock_commit_regs(struct ring_buffer *buffer, struct ring_buffer_event *event, unsigned long flags, int pc, struct pt_regs *regs) { __buffer_unlock_commit(buffer, event); ftrace_trace_stack_regs(buffer, flags, 0, pc, regs); ftrace_trace_userstack(buffer, flags, pc); } EXPORT_SYMBOL_GPL(trace_buffer_unlock_commit_regs); void trace_current_buffer_discard_commit(struct ring_buffer *buffer, struct ring_buffer_event *event) { ring_buffer_discard_commit(buffer, event); } EXPORT_SYMBOL_GPL(trace_current_buffer_discard_commit); void trace_function(struct trace_array *tr, unsigned long ip, unsigned long parent_ip, unsigned long flags, int pc) { struct ftrace_event_call *call = &event_function; struct ring_buffer *buffer = tr->trace_buffer.buffer; struct ring_buffer_event *event; struct ftrace_entry *entry; /* If we are reading the ring buffer, don't trace */ if (unlikely(__this_cpu_read(ftrace_cpu_disabled))) return; event = trace_buffer_lock_reserve(buffer, TRACE_FN, sizeof(*entry), flags, pc); if (!event) return; entry = ring_buffer_event_data(event); entry->ip = ip; entry->parent_ip = parent_ip; if (!filter_check_discard(call, entry, buffer, event)) __buffer_unlock_commit(buffer, event); } 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); } #ifdef CONFIG_STACKTRACE #define FTRACE_STACK_MAX_ENTRIES (PAGE_SIZE / sizeof(unsigned long)) struct ftrace_stack { unsigned long calls[FTRACE_STACK_MAX_ENTRIES]; }; static DEFINE_PER_CPU(struct ftrace_stack, ftrace_stack); static DEFINE_PER_CPU(int, ftrace_stack_reserve); static void __ftrace_trace_stack(struct ring_buffer *buffer, unsigned long flags, int skip, int pc, struct pt_regs *regs) { struct ftrace_event_call *call = &event_kernel_stack; struct ring_buffer_event *event; struct stack_entry *entry; struct stack_trace trace; int use_stack; int size = FTRACE_STACK_ENTRIES; trace.nr_entries = 0; trace.skip = skip; /* * Since events can happen in NMIs there's no safe way to * use the per cpu ftrace_stacks. We reserve it and if an interrupt * or NMI comes in, it will just have to use the default * FTRACE_STACK_SIZE. */ preempt_disable_notrace(); use_stack = __this_cpu_inc_return(ftrace_stack_reserve); /* * We don't need any atomic variables, just a barrier. * If an interrupt comes in, we don't care, because it would * have exited and put the counter back to what we want. * We just need a barrier to keep gcc from moving things * around. */ barrier(); if (use_stack == 1) { trace.entries = &__get_cpu_var(ftrace_stack).calls[0]; trace.max_entries = FTRACE_STACK_MAX_ENTRIES; if (regs) save_stack_trace_regs(regs, &trace); else save_stack_trace(&trace); if (trace.nr_entries > size) size = trace.nr_entries; } else /* From now on, use_stack is a boolean */ use_stack = 0; size *= sizeof(unsigned long); event = trace_buffer_lock_reserve(buffer, TRACE_STACK, sizeof(*entry) + size, flags, pc); if (!event) goto out; entry = ring_buffer_event_data(event); memset(&entry->caller, 0, size); if (use_stack) memcpy(&entry->caller, trace.entries, trace.nr_entries * sizeof(unsigned long)); else { trace.max_entries = FTRACE_STACK_ENTRIES; trace.entries = entry->caller; if (regs) save_stack_trace_regs(regs, &trace); else save_stack_trace(&trace); } entry->size = trace.nr_entries; if (!filter_check_discard(call, entry, buffer, event)) __buffer_unlock_commit(buffer, event); out: /* Again, don't let gcc optimize things here */ barrier(); __this_cpu_dec(ftrace_stack_reserve); preempt_enable_notrace(); } void ftrace_trace_stack_regs(struct ring_buffer *buffer, unsigned long flags, int skip, int pc, struct pt_regs *regs) { if (!(trace_flags & TRACE_ITER_STACKTRACE)) return; __ftrace_trace_stack(buffer, flags, skip, pc, regs); } void ftrace_trace_stack(struct ring_buffer *buffer, unsigned long flags, int skip, int pc) { if (!(trace_flags & TRACE_ITER_STACKTRACE)) return; __ftrace_trace_stack(buffer, flags, skip, pc, NULL); } void __trace_stack(struct trace_array *tr, unsigned long flags, int skip, int pc) { __ftrace_trace_stack(tr->trace_buffer.buffer, flags, skip, pc, NULL); } /** * trace_dump_stack - record a stack back trace in the trace buffer */ void trace_dump_stack(void) { unsigned long flags; if (tracing_disabled || tracing_selftest_running) return; local_save_flags(flags); /* skipping 3 traces, seems to get us at the caller of this function */ __ftrace_trace_stack(global_trace.trace_buffer.buffer, flags, 3, preempt_count(), NULL); } static DEFINE_PER_CPU(int, user_stack_count); void ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags, int pc) { struct ftrace_event_call *call = &event_user_stack; struct ring_buffer_event *event; struct userstack_entry *entry; struct stack_trace trace; if (!(trace_flags & TRACE_ITER_USERSTACKTRACE)) return; /* * NMIs can not handle page faults, even with fix ups. * The save user stack can (and often does) fault. */ if (unlikely(in_nmi())) return; /* * prevent recursion, since the user stack tracing may * trigger other kernel events. */ preempt_disable(); if (__this_cpu_read(user_stack_count)) goto out; __this_cpu_inc(user_stack_count); event = trace_buffer_lock_reserve(buffer, TRACE_USER_STACK, sizeof(*entry), flags, pc); if (!event) goto out_drop_count; entry = ring_buffer_event_data(event); entry->tgid = current->tgid; 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); if (!filter_check_discard(call, entry, buffer, event)) __buffer_unlock_commit(buffer, event); out_drop_count: __this_cpu_dec(user_stack_count); out: preempt_enable(); } #ifdef UNUSED static void __trace_userstack(struct trace_array *tr, unsigned long flags) { ftrace_trace_userstack(tr, flags, preempt_count()); } #endif /* UNUSED */ #endif /* CONFIG_STACKTRACE */ /* created for use with alloc_percpu */ struct trace_buffer_struct { char buffer[TRACE_BUF_SIZE]; }; static struct trace_buffer_struct *trace_percpu_buffer; static struct trace_buffer_struct *trace_percpu_sirq_buffer; static struct trace_buffer_struct *trace_percpu_irq_buffer; static struct trace_buffer_struct *trace_percpu_nmi_buffer; /* * The buffer used is dependent on the context. There is a per cpu * buffer for normal context, softirq contex, hard irq context and * for NMI context. Thise allows for lockless recording. * * Note, if the buffers failed to be allocated, then this returns NULL */ static char *get_trace_buf(void) { struct trace_buffer_struct *percpu_buffer; /* * If we have allocated per cpu buffers, then we do not * need to do any locking. */ if (in_nmi()) percpu_buffer = trace_percpu_nmi_buffer; else if (in_irq()) percpu_buffer = trace_percpu_irq_buffer; else if (in_softirq()) percpu_buffer = trace_percpu_sirq_buffer; else percpu_buffer = trace_percpu_buffer; if (!percpu_buffer) return NULL; return this_cpu_ptr(&percpu_buffer->buffer[0]); } static int alloc_percpu_trace_buffer(void) { struct trace_buffer_struct *buffers; struct trace_buffer_struct *sirq_buffers; struct trace_buffer_struct *irq_buffers; struct trace_buffer_struct *nmi_buffers; buffers = alloc_percpu(struct trace_buffer_struct); if (!buffers) goto err_warn; sirq_buffers = alloc_percpu(struct trace_buffer_struct); if (!sirq_buffers) goto err_sirq; irq_buffers = alloc_percpu(struct trace_buffer_struct); if (!irq_buffers) goto err_irq; nmi_buffers = alloc_percpu(struct trace_buffer_struct); if (!nmi_buffers) goto err_nmi; trace_percpu_buffer = buffers; trace_percpu_sirq_buffer = sirq_buffers; trace_percpu_irq_buffer = irq_buffers; trace_percpu_nmi_buffer = nmi_buffers; return 0; err_nmi: free_percpu(irq_buffers); err_irq: free_percpu(sirq_buffers); err_sirq: free_percpu(buffers); err_warn: WARN(1, "Could not allocate percpu trace_printk buffer"); return -ENOMEM; } static int buffers_allocated; void trace_printk_init_buffers(void) { if (buffers_allocated) return; if (alloc_percpu_trace_buffer()) return; pr_info("ftrace: Allocated trace_printk buffers\n"); /* Expand the buffers to set size */ tracing_update_buffers(); buffers_allocated = 1; /* * trace_printk_init_buffers() can be called by modules. * If that happens, then we need to start cmdline recording * directly here. If the global_trace.buffer is already * allocated here, then this was called by module code. */ if (global_trace.trace_buffer.buffer) tracing_start_cmdline_record(); } void trace_printk_start_comm(void) { /* Start tracing comms if trace printk is set */ if (!buffers_allocated) return; tracing_start_cmdline_record(); } static void trace_printk_start_stop_comm(int enabled) { if (!buffers_allocated) return; if (enabled) tracing_start_cmdline_record(); else tracing_stop_cmdline_record(); } /** * trace_vbprintk - write binary msg to tracing buffer * */ int trace_vbprintk(unsigned long ip, const char *fmt, va_list args) { struct ftrace_event_call *call = &event_bprint; struct ring_buffer_event *event; struct ring_buffer *buffer; struct trace_array *tr = &global_trace; struct bprint_entry *entry; unsigned long flags; char *tbuffer; int 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(); preempt_disable_notrace(); tbuffer = get_trace_buf(); if (!tbuffer) { len = 0; goto out; } len = vbin_printf((u32 *)tbuffer, TRACE_BUF_SIZE/sizeof(int), fmt, args); if (len > TRACE_BUF_SIZE/sizeof(int) || len < 0) goto out; local_save_flags(flags); size = sizeof(*entry) + sizeof(u32) * len; buffer = tr->trace_buffer.buffer; event = trace_buffer_lock_reserve(buffer, TRACE_BPRINT, size, flags, pc); if (!event) goto out; entry = ring_buffer_event_data(event); entry->ip = ip; entry->fmt = fmt; memcpy(entry->buf, tbuffer, sizeof(u32) * len); if (!filter_check_discard(call, entry, buffer, event)) { __buffer_unlock_commit(buffer, event); ftrace_trace_stack(buffer, flags, 6, pc); } out: preempt_enable_notrace(); unpause_graph_tracing(); return len; } EXPORT_SYMBOL_GPL(trace_vbprintk); static int __trace_array_vprintk(struct ring_buffer *buffer, unsigned long ip, const char *fmt, va_list args) { struct ftrace_event_call *call = &event_print; struct ring_buffer_event *event; int len = 0, size, pc; struct print_entry *entry; unsigned long flags; char *tbuffer; if (tracing_disabled || tracing_selftest_running) return 0; /* Don't pollute graph traces with trace_vprintk internals */ pause_graph_tracing(); pc = preempt_count(); preempt_disable_notrace(); tbuffer = get_trace_buf(); if (!tbuffer) { len = 0; goto out; } len = vsnprintf(tbuffer, TRACE_BUF_SIZE, fmt, args); if (len > TRACE_BUF_SIZE) goto out; local_save_flags(flags); size = sizeof(*entry) + len + 1; event = trace_buffer_lock_reserve(buffer, TRACE_PRINT, size, flags, pc); if (!event) goto out; entry = ring_buffer_event_data(event); entry->ip = ip; memcpy(&entry->buf, tbuffer, len); entry->buf[len] = '\0'; if (!filter_check_discard(call, entry, buffer, event)) { __buffer_unlock_commit(buffer, event); ftrace_trace_stack(buffer, flags, 6, pc); } out: preempt_enable_notrace(); unpause_graph_tracing(); return len; } int trace_array_vprintk(struct trace_array *tr, unsigned long ip, const char *fmt, va_list args) { return __trace_array_vprintk(tr->trace_buffer.buffer, ip, fmt, args); } int trace_array_printk(struct trace_array *tr, 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_array_vprintk(tr, ip, fmt, ap); va_end(ap); return ret; } int trace_array_printk_buf(struct ring_buffer *buffer, 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_array_vprintk(buffer, ip, fmt, ap); va_end(ap); return ret; } int trace_vprintk(unsigned long ip, const char *fmt, va_list args) { return trace_array_vprintk(&global_trace, ip, fmt, args); } EXPORT_SYMBOL_GPL(trace_vprintk); static void trace_iterator_increment(struct trace_iterator *iter) { struct ring_buffer_iter *buf_iter = trace_buffer_iter(iter, iter->cpu); iter->idx++; if (buf_iter) ring_buffer_read(buf_iter, NULL); } static struct trace_entry * peek_next_entry(struct trace_iterator *iter, int cpu, u64 *ts, unsigned long *lost_events) { struct ring_buffer_event *event; struct ring_buffer_iter *buf_iter = trace_buffer_iter(iter, cpu); if (buf_iter) event = ring_buffer_iter_peek(buf_iter, ts); else event = ring_buffer_peek(iter->trace_buffer->buffer, cpu, ts, lost_events); if (event) { iter->ent_size = ring_buffer_event_length(event); return ring_buffer_event_data(event); } iter->ent_size = 0; return NULL; } static struct trace_entry * __find_next_entry(struct trace_iterator *iter, int *ent_cpu, unsigned long *missing_events, u64 *ent_ts) { struct ring_buffer *buffer = iter->trace_buffer->buffer; struct trace_entry *ent, *next = NULL; unsigned long lost_events = 0, next_lost = 0; int cpu_file = iter->cpu_file; u64 next_ts = 0, ts; int next_cpu = -1; int next_size = 0; 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 > RING_BUFFER_ALL_CPUS) { if (ring_buffer_empty_cpu(buffer, cpu_file)) return NULL; ent = peek_next_entry(iter, cpu_file, ent_ts, missing_events); 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, &lost_events); /* * Pick the entry with the smallest timestamp: */ if (ent && (!next || ts < next_ts)) { next = ent; next_cpu = cpu; next_ts = ts; next_lost = lost_events; next_size = iter->ent_size; } } iter->ent_size = next_size; if (ent_cpu) *ent_cpu = next_cpu; if (ent_ts) *ent_ts = next_ts; if (missing_events) *missing_events = next_lost; 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, NULL, ent_ts); } /* Find the next real entry, and increment the iterator to the next entry */ void *trace_find_next_entry_inc(struct trace_iterator *iter) { iter->ent = __find_next_entry(iter, &iter->cpu, &iter->lost_events, &iter->ts); if (iter->ent) trace_iterator_increment(iter); return iter->ent ? iter : NULL; } static void trace_consume(struct trace_iterator *iter) { ring_buffer_consume(iter->trace_buffer->buffer, iter->cpu, &iter->ts, &iter->lost_events); } 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; WARN_ON_ONCE(iter->leftover); (*pos)++; /* can't go backwards */ if (iter->idx > i) return NULL; if (iter->idx < 0) ent = trace_find_next_entry_inc(iter); else ent = iter; while (ent && iter->idx < i) ent = trace_find_next_entry_inc(iter); iter->pos = *pos; return ent; } void tracing_iter_reset(struct trace_iterator *iter, int cpu) { struct ring_buffer_event *event; struct ring_buffer_iter *buf_iter; unsigned long entries = 0; u64 ts; per_cpu_ptr(iter->trace_buffer->data, cpu)->skipped_entries = 0; buf_iter = trace_buffer_iter(iter, cpu); if (!buf_iter) return; ring_buffer_iter_reset(buf_iter); /* * We could have the case with the max latency tracers * that a reset never took place on a cpu. This is evident * by the timestamp being before the start of the buffer. */ while ((event = ring_buffer_iter_peek(buf_iter, &ts))) { if (ts >= iter->trace_buffer->time_start) break; entries++; ring_buffer_read(buf_iter, NULL); } per_cpu_ptr(iter->trace_buffer->data, cpu)->skipped_entries = entries; } /* * 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; struct trace_array *tr = iter->tr; 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. * iter->trace is a copy of current_trace, the pointer to the * name may be used instead of a strcmp(), as iter->trace->name * will point to the same string as current_trace->name. */ mutex_lock(&trace_types_lock); if (unlikely(tr->current_trace && iter->trace->name != tr->current_trace->name)) *iter->trace = *tr->current_trace; mutex_unlock(&trace_types_lock); #ifdef CONFIG_TRACER_MAX_TRACE if (iter->snapshot && iter->trace->use_max_tr) return ERR_PTR(-EBUSY); #endif if (!iter->snapshot) atomic_inc(&trace_record_cmdline_disabled); if (*pos != iter->pos) { iter->ent = NULL; iter->cpu = 0; iter->idx = -1; if (cpu_file == RING_BUFFER_ALL_CPUS) { for_each_tracing_cpu(cpu) tracing_iter_reset(iter, cpu); } else tracing_iter_reset(iter, cpu_file); iter->leftover = 0; for (p = iter; p && l < *pos; p = s_next(m, p, &l)) ; } else { /* * If we overflowed the seq_file before, then we want * to just reuse the trace_seq buffer again. */ if (iter->leftover) p = iter; else { l = *pos - 1; p = s_next(m, p, &l); } } trace_event_read_lock(); trace_access_lock(cpu_file); return p; } static void s_stop(struct seq_file *m, void *p) { struct trace_iterator *iter = m->private; #ifdef CONFIG_TRACER_MAX_TRACE if (iter->snapshot && iter->trace->use_max_tr) return; #endif if (!iter->snapshot) atomic_dec(&trace_record_cmdline_disabled); trace_access_unlock(iter->cpu_file); trace_event_read_unlock(); } static void get_total_entries(struct trace_buffer *buf, unsigned long *total, unsigned long *entries) { unsigned long count; int cpu; *total = 0; *entries = 0; for_each_tracing_cpu(cpu) { count = ring_buffer_entries_cpu(buf->buffer, cpu); /* * If this buffer has skipped entries, then we hold all * entries for the trace and we need to ignore the * ones before the time stamp. */ if (per_cpu_ptr(buf->data, cpu)->skipped_entries) { count -= per_cpu_ptr(buf->data, cpu)->skipped_entries; /* total is the same as the entries */ *total += count; } else *total += count + ring_buffer_overrun_cpu(buf->buffer, cpu); *entries += count; } } 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, "# |||| / delay \n"); seq_puts(m, "# cmd pid ||||| time | caller \n"); seq_puts(m, "# \\ / ||||| \\ | / \n"); } static void print_event_info(struct trace_buffer *buf, struct seq_file *m) { unsigned long total; unsigned long entries; get_total_entries(buf, &total, &entries); seq_printf(m, "# entries-in-buffer/entries-written: %lu/%lu #P:%d\n", entries, total, num_online_cpus()); seq_puts(m, "#\n"); } static void print_func_help_header(struct trace_buffer *buf, struct seq_file *m) { print_event_info(buf, m); seq_puts(m, "# TASK-PID CPU# TIMESTAMP FUNCTION\n"); seq_puts(m, "# | | | | |\n"); } static void print_func_help_header_irq(struct trace_buffer *buf, struct seq_file *m) { print_event_info(buf, m); 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, "# ||| / delay\n"); seq_puts(m, "# TASK-PID CPU# |||| TIMESTAMP FUNCTION\n"); seq_puts(m, "# | | | |||| | |\n"); } void print_trace_header(struct seq_file *m, struct trace_iterator *iter) { unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK); struct trace_buffer *buf = iter->trace_buffer; struct trace_array_cpu *data = per_cpu_ptr(buf->data, buf->cpu); struct tracer *type = iter->trace; unsigned long entries; unsigned long total; const char *name = "preemption"; name = type->name; get_total_entries(buf, &total, &entries); 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, buf->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, from_kuid_munged(seq_user_ns(m), 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#\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; if (per_cpu_ptr(iter->trace_buffer->data, iter->cpu)->skipped_entries) return; cpumask_set_cpu(iter->cpu, iter->started); /* Don't print started cpu buffer for the first entry of the trace */ if (iter->idx > 1) 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->funcs->trace(iter, sym_flags, event); 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->funcs->raw(iter, 0, event); 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->funcs->hex(iter, 0, event); 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->funcs->binary(iter, 0, event) : TRACE_TYPE_HANDLED; } int trace_empty(struct trace_iterator *iter) { struct ring_buffer_iter *buf_iter; int cpu; /* If we are looking at one CPU buffer, only check that one */ if (iter->cpu_file != RING_BUFFER_ALL_CPUS) { cpu = iter->cpu_file; buf_iter = trace_buffer_iter(iter, cpu); if (buf_iter) { if (!ring_buffer_iter_empty(buf_iter)) return 0; } else { if (!ring_buffer_empty_cpu(iter->trace_buffer->buffer, cpu)) return 0; } return 1; } for_each_tracing_cpu(cpu) { buf_iter = trace_buffer_iter(iter, cpu); if (buf_iter) { if (!ring_buffer_iter_empty(buf_iter)) return 0; } else { if (!ring_buffer_empty_cpu(iter->trace_buffer->buffer, cpu)) return 0; } } return 1; } /* Called with trace_event_read_lock() held. */ enum print_line_t print_trace_line(struct trace_iterator *iter) { enum print_line_t ret; if (iter->lost_events && !trace_seq_printf(&iter->seq, "CPU:%d [LOST %lu EVENTS]\n", iter->cpu, iter->lost_events)) return TRACE_TYPE_PARTIAL_LINE; 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_BPUTS && trace_flags & TRACE_ITER_PRINTK && trace_flags & TRACE_ITER_PRINTK_MSGONLY) return trace_print_bputs_msg_only(iter); 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); } void trace_latency_header(struct seq_file *m) { struct trace_iterator *iter = m->private; /* print nothing if the buffers are empty */ if (trace_empty(iter)) return; if (iter->iter_flags & TRACE_FILE_LAT_FMT) print_trace_header(m, iter); if (!(trace_flags & TRACE_ITER_VERBOSE)) print_lat_help_header(m); } void trace_default_header(struct seq_file *m) { struct trace_iterator *iter = m->private; if (!(trace_flags & TRACE_ITER_CONTEXT_INFO)) return; if (iter->iter_flags & TRACE_FILE_LAT_FMT) { /* print nothing if the buffers are empty */ if (trace_empty(iter)) return; print_trace_header(m, iter); if (!(trace_flags & TRACE_ITER_VERBOSE)) print_lat_help_header(m); } else { if (!(trace_flags & TRACE_ITER_VERBOSE)) { if (trace_flags & TRACE_ITER_IRQ_INFO) print_func_help_header_irq(iter->trace_buffer, m); else print_func_help_header(iter->trace_buffer, m); } } } static void test_ftrace_alive(struct seq_file *m) { if (!ftrace_is_dead()) return; seq_printf(m, "# WARNING: FUNCTION TRACING IS CORRUPTED\n"); seq_printf(m, "# MAY BE MISSING FUNCTION EVENTS\n"); } #ifdef CONFIG_TRACER_MAX_TRACE static void show_snapshot_main_help(struct seq_file *m) { seq_printf(m, "# echo 0 > snapshot : Clears and frees snapshot buffer\n"); seq_printf(m, "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n"); seq_printf(m, "# Takes a snapshot of the main buffer.\n"); seq_printf(m, "# echo 2 > snapshot : Clears snapshot buffer (but does not allocate)\n"); seq_printf(m, "# (Doesn't have to be '2' works with any number that\n"); seq_printf(m, "# is not a '0' or '1')\n"); } static void show_snapshot_percpu_help(struct seq_file *m) { seq_printf(m, "# echo 0 > snapshot : Invalid for per_cpu snapshot file.\n"); #ifdef CONFIG_RING_BUFFER_ALLOW_SWAP seq_printf(m, "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n"); seq_printf(m, "# Takes a snapshot of the main buffer for this cpu.\n"); #else seq_printf(m, "# echo 1 > snapshot : Not supported with this kernel.\n"); seq_printf(m, "# Must use main snapshot file to allocate.\n"); #endif seq_printf(m, "# echo 2 > snapshot : Clears this cpu's snapshot buffer (but does not allocate)\n"); seq_printf(m, "# (Doesn't have to be '2' works with any number that\n"); seq_printf(m, "# is not a '0' or '1')\n"); } static void print_snapshot_help(struct seq_file *m, struct trace_iterator *iter) { if (iter->tr->allocated_snapshot) seq_printf(m, "#\n# * Snapshot is allocated *\n#\n"); else seq_printf(m, "#\n# * Snapshot is freed *\n#\n"); seq_printf(m, "# Snapshot commands:\n"); if (iter->cpu_file == RING_BUFFER_ALL_CPUS) show_snapshot_main_help(m); else show_snapshot_percpu_help(m); } #else /* Should never be called */ static inline void print_snapshot_help(struct seq_file *m, struct trace_iterator *iter) { } #endif static int s_show(struct seq_file *m, void *v) { struct trace_iterator *iter = v; int ret; if (iter->ent == NULL) { if (iter->tr) { seq_printf(m, "# tracer: %s\n", iter->trace->name); seq_puts(m, "#\n"); test_ftrace_alive(m); } if (iter->snapshot && trace_empty(iter)) print_snapshot_help(m, iter); else if (iter->trace && iter->trace->print_header) iter->trace->print_header(m); else trace_default_header(m); } else if (iter->leftover) { /* * If we filled the seq_file buffer earlier, we * want to just show it now. */ ret = trace_print_seq(m, &iter->seq); /* ret should this time be zero, but you never know */ iter->leftover = ret; } else { print_trace_line(iter); ret = trace_print_seq(m, &iter->seq); /* * If we overflow the seq_file buffer, then it will * ask us for this data again at start up. * Use that instead. * ret is 0 if seq_file write succeeded. * -1 otherwise. */ iter->leftover = ret; } return 0; } static const 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, bool snapshot) { struct trace_cpu *tc = inode->i_private; struct trace_array *tr = tc->tr; struct trace_iterator *iter; int cpu; if (tracing_disabled) return ERR_PTR(-ENODEV); iter = __seq_open_private(file, &tracer_seq_ops, sizeof(*iter)); if (!iter) return ERR_PTR(-ENOMEM); iter->buffer_iter = kzalloc(sizeof(*iter->buffer_iter) * num_possible_cpus(), GFP_KERNEL); if (!iter->buffer_iter) goto release; /* * 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; *iter->trace = *tr->current_trace; if (!zalloc_cpumask_var(&iter->started, GFP_KERNEL)) goto fail; iter->tr = tr; #ifdef CONFIG_TRACER_MAX_TRACE /* Currently only the top directory has a snapshot */ if (tr->current_trace->print_max || snapshot) iter->trace_buffer = &tr->max_buffer; else #endif iter->trace_buffer = &tr->trace_buffer; iter->snapshot = snapshot; iter->pos = -1; mutex_init(&iter->mutex); iter->cpu_file = tc->cpu; /* 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->trace_buffer->buffer)) iter->iter_flags |= TRACE_FILE_ANNOTATE; /* Output in nanoseconds only if we are using a clock in nanoseconds. */ if (trace_clocks[trace_clock_id].in_ns) iter->iter_flags |= TRACE_FILE_TIME_IN_NS; /* stop the trace while dumping if we are not opening "snapshot" */ if (!iter->snapshot) tracing_stop_tr(tr); if (iter->cpu_file == RING_BUFFER_ALL_CPUS) { for_each_tracing_cpu(cpu) { iter->buffer_iter[cpu] = ring_buffer_read_prepare(iter->trace_buffer->buffer, cpu); } ring_buffer_read_prepare_sync(); for_each_tracing_cpu(cpu) { ring_buffer_read_start(iter->buffer_iter[cpu]); tracing_iter_reset(iter, cpu); } } else { cpu = iter->cpu_file; iter->buffer_iter[cpu] = ring_buffer_read_prepare(iter->trace_buffer->buffer, cpu); ring_buffer_read_prepare_sync(); ring_buffer_read_start(iter->buffer_iter[cpu]); tracing_iter_reset(iter, cpu); } tr->ref++; mutex_unlock(&trace_types_lock); return iter; fail: mutex_unlock(&trace_types_lock); kfree(iter->trace); kfree(iter->buffer_iter); release: seq_release_private(inode, file); 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; } static int tracing_release(struct inode *inode, struct file *file) { struct seq_file *m = file->private_data; struct trace_iterator *iter; struct trace_array *tr; int cpu; if (!(file->f_mode & FMODE_READ)) return 0; iter = m->private; tr = iter->tr; mutex_lock(&trace_types_lock); WARN_ON(!tr->ref); tr->ref--; 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); if (!iter->snapshot) /* reenable tracing if it was previously enabled */ tracing_start_tr(tr); mutex_unlock(&trace_types_lock); mutex_destroy(&iter->mutex); free_cpumask_var(iter->started); kfree(iter->trace); kfree(iter->buffer_iter); seq_release_private(inode, file); 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_TRUNC)) { struct trace_cpu *tc = inode->i_private; struct trace_array *tr = tc->tr; if (tc->cpu == RING_BUFFER_ALL_CPUS) tracing_reset_online_cpus(&tr->trace_buffer); else tracing_reset(&tr->trace_buffer, tc->cpu); } if (file->f_mode & FMODE_READ) { iter = __tracing_open(inode, file, false); 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 = v; (*pos)++; if (t) t = t->next; return t; } static void *t_start(struct seq_file *m, loff_t *pos) { struct tracer *t; loff_t l = 0; mutex_lock(&trace_types_lock); for (t = trace_types; 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 const 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) { if (tracing_disabled) return -ENODEV; return seq_open(file, &show_traces_seq_ops); } static ssize_t tracing_write_stub(struct file *filp, const char __user *ubuf, size_t count, loff_t *ppos) { return count; } static loff_t tracing_seek(struct file *file, loff_t offset, int origin) { if (file->f_mode & FMODE_READ) return seq_lseek(file, offset, origin); else return 0; } static const struct file_operations tracing_fops = { .open = tracing_open, .read = seq_read, .write = tracing_write_stub, .llseek = tracing_seek, .release = tracing_release, }; static const struct file_operations show_traces_fops = { .open = show_traces_open, .read = seq_read, .release = seq_release, .llseek = seq_lseek, }; /* * 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) { struct trace_array *tr = filp->private_data; cpumask_var_t tracing_cpumask_new; int err, cpu; if (!alloc_cpumask_var(&tracing_cpumask_new, GFP_KERNEL)) return -ENOMEM; err = cpumask_parse_user(ubuf, count, tracing_cpumask_new); if (err) goto err_unlock; mutex_lock(&tracing_cpumask_update_lock); local_irq_disable(); arch_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(&per_cpu_ptr(tr->trace_buffer.data, cpu)->disabled); ring_buffer_record_disable_cpu(tr->trace_buffer.buffer, cpu); } if (!cpumask_test_cpu(cpu, tracing_cpumask) && cpumask_test_cpu(cpu, tracing_cpumask_new)) { atomic_dec(&per_cpu_ptr(tr->trace_buffer.data, cpu)->disabled); ring_buffer_record_enable_cpu(tr->trace_buffer.buffer, cpu); } } arch_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: free_cpumask_var(tracing_cpumask_new); return err; } static const struct file_operations tracing_cpumask_fops = { .open = tracing_open_generic, .read = tracing_cpumask_read, .write = tracing_cpumask_write, .llseek = generic_file_llseek, }; static int tracing_trace_options_show(struct seq_file *m, void *v) { struct tracer_opt *trace_opts; struct trace_array *tr = m->private; u32 tracer_flags; int i; mutex_lock(&trace_types_lock); tracer_flags = tr->current_trace->flags->val; trace_opts = tr->current_trace->flags->opts; for (i = 0; trace_options[i]; i++) { if (trace_flags & (1 << i)) seq_printf(m, "%s\n", trace_options[i]); else seq_printf(m, "no%s\n", trace_options[i]); } for (i = 0; trace_opts[i].name; i++) { if (tracer_flags & trace_opts[i].bit) seq_printf(m, "%s\n", trace_opts[i].name); else seq_printf(m, "no%s\n", trace_opts[i].name); } mutex_unlock(&trace_types_lock); return 0; } static int __set_tracer_option(struct tracer *trace, struct tracer_flags *tracer_flags, struct tracer_opt *opts, int neg) { int ret; ret = trace->set_flag(tracer_flags->val, opts->bit, !neg); if (ret) return ret; if (neg) tracer_flags->val &= ~opts->bit; else tracer_flags->val |= opts->bit; return 0; } /* Try to assign a tracer specific option */ static int set_tracer_option(struct tracer *trace, char *cmp, int neg) { struct tracer_flags *tracer_flags = trace->flags; struct tracer_opt *opts = NULL; int i; for (i = 0; tracer_flags->opts[i].name; i++) { opts = &tracer_flags->opts[i]; if (strcmp(cmp, opts->name) == 0) return __set_tracer_option(trace, trace->flags, opts, neg); } return -EINVAL; } /* Some tracers require overwrite to stay enabled */ int trace_keep_overwrite(struct tracer *tracer, u32 mask, int set) { if (tracer->enabled && (mask & TRACE_ITER_OVERWRITE) && !set) return -1; return 0; } int set_tracer_flag(struct trace_array *tr, unsigned int mask, int enabled) { /* do nothing if flag is already set */ if (!!(trace_flags & mask) == !!enabled) return 0; /* Give the tracer a chance to approve the change */ if (tr->current_trace->flag_changed) if (tr->current_trace->flag_changed(tr->current_trace, mask, !!enabled)) return -EINVAL; if (enabled) trace_flags |= mask; else trace_flags &= ~mask; if (mask == TRACE_ITER_RECORD_CMD) trace_event_enable_cmd_record(enabled); if (mask == TRACE_ITER_OVERWRITE) { ring_buffer_change_overwrite(tr->trace_buffer.buffer, enabled); #ifdef CONFIG_TRACER_MAX_TRACE ring_buffer_change_overwrite(tr->max_buffer.buffer, enabled); #endif } if (mask == TRACE_ITER_PRINTK) trace_printk_start_stop_comm(enabled); return 0; } static int trace_set_options(struct trace_array *tr, char *option) { char *cmp; int neg = 0; int ret = -ENODEV; int i; cmp = strstrip(option); if (strncmp(cmp, "no", 2) == 0) { neg = 1; cmp += 2; } mutex_lock(&trace_types_lock); for (i = 0; trace_options[i]; i++) { if (strcmp(cmp, trace_options[i]) == 0) { ret = set_tracer_flag(tr, 1 << i, !neg); break; } } /* If no option could be set, test the specific tracer options */ if (!trace_options[i]) ret = set_tracer_option(tr->current_trace, cmp, neg); mutex_unlock(&trace_types_lock); return ret; } static ssize_t tracing_trace_options_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *ppos) { struct seq_file *m = filp->private_data; struct trace_array *tr = m->private; char buf[64]; int ret; if (cnt >= sizeof(buf)) return -EINVAL; if (copy_from_user(&buf, ubuf, cnt)) return -EFAULT; buf[cnt] = 0; ret = trace_set_options(tr, buf); if (ret < 0) return ret; *ppos += cnt; return cnt; } static int tracing_trace_options_open(struct inode *inode, struct file *file) { if (tracing_disabled) return -ENODEV; return single_open(file, tracing_trace_options_show, inode->i_private); } static const struct file_operations tracing_iter_fops = { .open = tracing_trace_options_open, .read = seq_read, .llseek = seq_lseek, .release = single_release, .write = tracing_trace_options_write, }; static const char readme_msg[] = "tracing mini-HOWTO:\n\n" "# mount -t debugfs nodev /sys/kernel/debug\n\n" "# cat /sys/kernel/debug/tracing/available_tracers\n" "wakeup wakeup_rt preemptirqsoff preemptoff irqsoff function nop\n\n" "# cat /sys/kernel/debug/tracing/current_tracer\n" "nop\n" "# echo wakeup > /sys/kernel/debug/tracing/current_tracer\n" "# cat /sys/kernel/debug/tracing/current_tracer\n" "wakeup\n" "# cat /sys/kernel/debug/tracing/trace_options\n" "noprint-parent nosym-offset nosym-addr noverbose\n" "# echo print-parent > /sys/kernel/debug/tracing/trace_options\n" "# echo 1 > /sys/kernel/debug/tracing/tracing_on\n" "# cat /sys/kernel/debug/tracing/trace > /tmp/trace.txt\n" "# echo 0 > /sys/kernel/debug/tracing/tracing_on\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, .llseek = generic_file_llseek, }; static ssize_t tracing_saved_cmdlines_read(struct file *file, char __user *ubuf, size_t cnt, loff_t *ppos) { char *buf_comm; char *file_buf; char *buf; int len = 0; int pid; int i; file_buf = kmalloc(SAVED_CMDLINES*(16+TASK_COMM_LEN), GFP_KERNEL); if (!file_buf) return -ENOMEM; buf_comm = kmalloc(TASK_COMM_LEN, GFP_KERNEL); if (!buf_comm) { kfree(file_buf); return -ENOMEM; } buf = file_buf; for (i = 0; i < SAVED_CMDLINES; i++) { int r; pid = map_cmdline_to_pid[i]; if (pid == -1 || pid == NO_CMDLINE_MAP) continue; trace_find_cmdline(pid, buf_comm); r = sprintf(buf, "%d %s\n", pid, buf_comm); buf += r; len += r; } len = simple_read_from_buffer(ubuf, cnt, ppos, file_buf, len); kfree(file_buf); kfree(buf_comm); return len; } static const struct file_operations tracing_saved_cmdlines_fops = { .open = tracing_open_generic, .read = tracing_saved_cmdlines_read, .llseek = generic_file_llseek, }; static ssize_t tracing_set_trace_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos) { struct trace_array *tr = filp->private_data; char buf[MAX_TRACER_SIZE+2]; int r; mutex_lock(&trace_types_lock); r = sprintf(buf, "%s\n", tr->current_trace->name); 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->trace_buffer); return t->init(tr); } static void set_buffer_entries(struct trace_buffer *buf, unsigned long val) { int cpu; for_each_tracing_cpu(cpu) per_cpu_ptr(buf->data, cpu)->entries = val; } #ifdef CONFIG_TRACER_MAX_TRACE /* resize @tr's buffer to the size of @size_tr's entries */ static int resize_buffer_duplicate_size(struct trace_buffer *trace_buf, struct trace_buffer *size_buf, int cpu_id) { int cpu, ret = 0; if (cpu_id == RING_BUFFER_ALL_CPUS) { for_each_tracing_cpu(cpu) { ret = ring_buffer_resize(trace_buf->buffer, per_cpu_ptr(size_buf->data, cpu)->entries, cpu); if (ret < 0) break; per_cpu_ptr(trace_buf->data, cpu)->entries = per_cpu_ptr(size_buf->data, cpu)->entries; } } else { ret = ring_buffer_resize(trace_buf->buffer, per_cpu_ptr(size_buf->data, cpu_id)->entries, cpu_id); if (ret == 0) per_cpu_ptr(trace_buf->data, cpu_id)->entries = per_cpu_ptr(size_buf->data, cpu_id)->entries; } return ret; } #endif /* CONFIG_TRACER_MAX_TRACE */ static int __tracing_resize_ring_buffer(struct trace_array *tr, unsigned long size, int cpu) { 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 = true; /* May be called before buffers are initialized */ if (!tr->trace_buffer.buffer) return 0; ret = ring_buffer_resize(tr->trace_buffer.buffer, size, cpu); if (ret < 0) return ret; #ifdef CONFIG_TRACER_MAX_TRACE if (!(tr->flags & TRACE_ARRAY_FL_GLOBAL) || !tr->current_trace->use_max_tr) goto out; ret = ring_buffer_resize(tr->max_buffer.buffer, size, cpu); if (ret < 0) { int r = resize_buffer_duplicate_size(&tr->trace_buffer, &tr->trace_buffer, cpu); 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; } if (cpu == RING_BUFFER_ALL_CPUS) set_buffer_entries(&tr->max_buffer, size); else per_cpu_ptr(tr->max_buffer.data, cpu)->entries = size; out: #endif /* CONFIG_TRACER_MAX_TRACE */ if (cpu == RING_BUFFER_ALL_CPUS) set_buffer_entries(&tr->trace_buffer, size); else per_cpu_ptr(tr->trace_buffer.data, cpu)->entries = size; return ret; } static ssize_t tracing_resize_ring_buffer(struct trace_array *tr, unsigned long size, int cpu_id) { int ret = size; mutex_lock(&trace_types_lock); if (cpu_id != RING_BUFFER_ALL_CPUS) { /* make sure, this cpu is enabled in the mask */ if (!cpumask_test_cpu(cpu_id, tracing_buffer_mask)) { ret = -EINVAL; goto out; } } ret = __tracing_resize_ring_buffer(tr, size, cpu_id); if (ret < 0) ret = -ENOMEM; out: mutex_unlock(&trace_types_lock); 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(&global_trace, trace_buf_size, RING_BUFFER_ALL_CPUS); mutex_unlock(&trace_types_lock); return ret; } struct trace_option_dentry; static struct trace_option_dentry * create_trace_option_files(struct trace_array *tr, 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; #ifdef CONFIG_TRACER_MAX_TRACE bool had_max_tr; #endif int ret = 0; mutex_lock(&trace_types_lock); if (!ring_buffer_expanded) { ret = __tracing_resize_ring_buffer(tr, trace_buf_size, RING_BUFFER_ALL_CPUS); 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 == tr->current_trace) goto out; trace_branch_disable(); tr->current_trace->enabled = false; if (tr->current_trace->reset) tr->current_trace->reset(tr); /* Current trace needs to be nop_trace before synchronize_sched */ tr->current_trace = &nop_trace; #ifdef CONFIG_TRACER_MAX_TRACE had_max_tr = tr->allocated_snapshot; if (had_max_tr && !t->use_max_tr) { /* * We need to make sure that the update_max_tr sees that * current_trace changed to nop_trace to keep it from * swapping the buffers after we resize it. * The update_max_tr is called from interrupts disabled * so a synchronized_sched() is sufficient. */ synchronize_sched(); free_snapshot(tr); } #endif destroy_trace_option_files(topts); topts = create_trace_option_files(tr, t); #ifdef CONFIG_TRACER_MAX_TRACE if (t->use_max_tr && !had_max_tr) { ret = alloc_snapshot(tr); if (ret < 0) goto out; } #endif if (t->init) { ret = tracer_init(t, tr); if (ret) goto out; } tr->current_trace = t; tr->current_trace->enabled = true; 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_SIZE+1]; int i; size_t ret; int err; ret = cnt; if (cnt > MAX_TRACER_SIZE) cnt = MAX_TRACER_SIZE; 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; *ppos += 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; unsigned long val; int ret; ret = kstrtoul_from_user(ubuf, cnt, 10, &val); if (ret) return ret; *ptr = val * 1000; return cnt; } static int tracing_open_pipe(struct inode *inode, struct file *filp) { struct trace_cpu *tc = inode->i_private; struct trace_array *tr = tc->tr; struct trace_iterator *iter; int ret = 0; if (tracing_disabled) return -ENODEV; mutex_lock(&trace_types_lock); /* 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; } *iter->trace = *tr->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); if (trace_flags & TRACE_ITER_LATENCY_FMT) iter->iter_flags |= TRACE_FILE_LAT_FMT; /* Output in nanoseconds only if we are using a clock in nanoseconds. */ if (trace_clocks[trace_clock_id].in_ns) iter->iter_flags |= TRACE_FILE_TIME_IN_NS; iter->cpu_file = tc->cpu; iter->tr = tc->tr; iter->trace_buffer = &tc->tr->trace_buffer; mutex_init(&iter->mutex); filp->private_data = iter; if (iter->trace->pipe_open) iter->trace->pipe_open(iter); nonseekable_open(inode, filp); 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->trace->pipe_close) iter->trace->pipe_close(iter); mutex_unlock(&trace_types_lock); free_cpumask_var(iter->started); mutex_destroy(&iter->mutex); kfree(iter->trace); kfree(iter); return 0; } static unsigned int trace_poll(struct trace_iterator *iter, struct file *filp, poll_table *poll_table) { /* Iterators are static, they should be filled or empty */ if (trace_buffer_iter(iter, iter->cpu_file)) return POLLIN | POLLRDNORM; if (trace_flags & TRACE_ITER_BLOCK) /* * Always select as readable when in blocking mode */ return POLLIN | POLLRDNORM; else return ring_buffer_poll_wait(iter->trace_buffer->buffer, iter->cpu_file, filp, poll_table); } static unsigned int tracing_poll_pipe(struct file *filp, poll_table *poll_table) { struct trace_iterator *iter = filp->private_data; return trace_poll(iter, filp, poll_table); } /* * 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 (!tracing_is_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; struct trace_array *tr = iter->tr; 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(iter->trace->name != tr->current_trace->name)) *iter->trace = *tr->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; trace_event_read_lock(); trace_access_lock(iter->cpu_file); while (trace_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; /* * Setting the full flag means we reached the trace_seq buffer * size and we should leave by partial output condition above. * One of the trace_seq_* functions is not used properly. */ WARN_ONCE(iter->seq.full, "full flag set for trace type %d", iter->ent->type); } trace_access_unlock(iter->cpu_file); trace_event_read_unlock(); /* 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, in spite 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 const 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; } if (ret != TRACE_TYPE_NO_CONSUME) trace_consume(iter); rem -= count; if (!trace_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_def[PIPE_DEF_BUFFERS]; struct partial_page partial_def[PIPE_DEF_BUFFERS]; struct trace_iterator *iter = filp->private_data; struct splice_pipe_desc spd = { .pages = pages_def, .partial = partial_def, .nr_pages = 0, /* This gets updated below. */ .nr_pages_max = PIPE_DEF_BUFFERS, .flags = flags, .ops = &tracing_pipe_buf_ops, .spd_release = tracing_spd_release_pipe, }; struct trace_array *tr = iter->tr; ssize_t ret; size_t rem; unsigned int i; if (splice_grow_spd(pipe, &spd)) return -ENOMEM; /* copy the tracer to avoid using a global lock all around */ mutex_lock(&trace_types_lock); if (unlikely(iter->trace->name != tr->current_trace->name)) *iter->trace = *tr->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 && !trace_find_next_entry_inc(iter)) { ret = -EFAULT; goto out_err; } trace_event_read_lock(); trace_access_lock(iter->cpu_file); /* Fill as many pages as possible. */ for (i = 0, rem = len; i < pipe->buffers && rem; i++) { spd.pages[i] = alloc_page(GFP_KERNEL); if (!spd.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(spd.pages[i]), iter->seq.len); if (ret < 0) { __free_page(spd.pages[i]); break; } spd.partial[i].offset = 0; spd.partial[i].len = iter->seq.len; trace_seq_init(&iter->seq); } trace_access_unlock(iter->cpu_file); trace_event_read_unlock(); mutex_unlock(&iter->mutex); spd.nr_pages = i; ret = splice_to_pipe(pipe, &spd); out: splice_shrink_spd(&spd); return ret; out_err: mutex_unlock(&iter->mutex); goto out; } static ssize_t tracing_entries_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos) { struct trace_cpu *tc = filp->private_data; struct trace_array *tr = tc->tr; char buf[64]; int r = 0; ssize_t ret; mutex_lock(&trace_types_lock); if (tc->cpu == RING_BUFFER_ALL_CPUS) { int cpu, buf_size_same; unsigned long size; size = 0; buf_size_same = 1; /* check if all cpu sizes are same */ for_each_tracing_cpu(cpu) { /* fill in the size from first enabled cpu */ if (size == 0) size = per_cpu_ptr(tr->trace_buffer.data, cpu)->entries; if (size != per_cpu_ptr(tr->trace_buffer.data, cpu)->entries) { buf_size_same = 0; break; } } if (buf_size_same) { if (!ring_buffer_expanded) r = sprintf(buf, "%lu (expanded: %lu)\n", size >> 10, trace_buf_size >> 10); else r = sprintf(buf, "%lu\n", size >> 10); } else r = sprintf(buf, "X\n"); } else r = sprintf(buf, "%lu\n", per_cpu_ptr(tr->trace_buffer.data, tc->cpu)->entries >> 10); mutex_unlock(&trace_types_lock); ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, r); return ret; } static ssize_t tracing_entries_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *ppos) { struct trace_cpu *tc = filp->private_data; unsigned long val; int ret; ret = kstrtoul_from_user(ubuf, cnt, 10, &val); if (ret) return ret; /* must have at least 1 entry */ if (!val) return -EINVAL; /* value is in KB */ val <<= 10; ret = tracing_resize_ring_buffer(tc->tr, val, tc->cpu); if (ret < 0) return ret; *ppos += cnt; return cnt; } static ssize_t tracing_total_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, cpu; unsigned long size = 0, expanded_size = 0; mutex_lock(&trace_types_lock); for_each_tracing_cpu(cpu) { size += per_cpu_ptr(tr->trace_buffer.data, cpu)->entries >> 10; if (!ring_buffer_expanded) expanded_size += trace_buf_size >> 10; } if (ring_buffer_expanded) r = sprintf(buf, "%lu\n", size); else r = sprintf(buf, "%lu (expanded: %lu)\n", size, expanded_size); mutex_unlock(&trace_types_lock); return simple_read_from_buffer(ubuf, cnt, ppos, buf, r); } static ssize_t tracing_free_buffer_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *ppos) { /* * There is no need to read what the user has written, this function * is just to make sure that there is no error when "echo" is used */ *ppos += cnt; return cnt; } static int tracing_free_buffer_release(struct inode *inode, struct file *filp) { struct trace_array *tr = inode->i_private; /* disable tracing ? */ if (trace_flags & TRACE_ITER_STOP_ON_FREE) tracing_off(); /* resize the ring buffer to 0 */ tracing_resize_ring_buffer(tr, 0, RING_BUFFER_ALL_CPUS); return 0; } static ssize_t tracing_mark_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *fpos) { unsigned long addr = (unsigned long)ubuf; struct ring_buffer_event *event; struct ring_buffer *buffer; struct print_entry *entry; unsigned long irq_flags; struct page *pages[2]; void *map_page[2]; int nr_pages = 1; ssize_t written; int offset; int size; int len; int ret; int i; if (tracing_disabled) return -EINVAL; if (!(trace_flags & TRACE_ITER_MARKERS)) return -EINVAL; if (cnt > TRACE_BUF_SIZE) cnt = TRACE_BUF_SIZE; /* * Userspace is injecting traces into the kernel trace buffer. * We want to be as non intrusive as possible. * To do so, we do not want to allocate any special buffers * or take any locks, but instead write the userspace data * straight into the ring buffer. * * First we need to pin the userspace buffer into memory, * which, most likely it is, because it just referenced it. * But there's no guarantee that it is. By using get_user_pages_fast() * and kmap_atomic/kunmap_atomic() we can get access to the * pages directly. We then write the data directly into the * ring buffer. */ BUILD_BUG_ON(TRACE_BUF_SIZE >= PAGE_SIZE); /* check if we cross pages */ if ((addr & PAGE_MASK) != ((addr + cnt) & PAGE_MASK)) nr_pages = 2; offset = addr & (PAGE_SIZE - 1); addr &= PAGE_MASK; ret = get_user_pages_fast(addr, nr_pages, 0, pages); if (ret < nr_pages) { while (--ret >= 0) put_page(pages[ret]); written = -EFAULT; goto out; } for (i = 0; i < nr_pages; i++) map_page[i] = kmap_atomic(pages[i]); local_save_flags(irq_flags); size = sizeof(*entry) + cnt + 2; /* possible \n added */ buffer = global_trace.trace_buffer.buffer; event = trace_buffer_lock_reserve(buffer, TRACE_PRINT, size, irq_flags, preempt_count()); if (!event) { /* Ring buffer disabled, return as if not open for write */ written = -EBADF; goto out_unlock; } entry = ring_buffer_event_data(event); entry->ip = _THIS_IP_; if (nr_pages == 2) { len = PAGE_SIZE - offset; memcpy(&entry->buf, map_page[0] + offset, len); memcpy(&entry->buf[len], map_page[1], cnt - len); } else memcpy(&entry->buf, map_page[0] + offset, cnt); if (entry->buf[cnt - 1] != '\n') { entry->buf[cnt] = '\n'; entry->buf[cnt + 1] = '\0'; } else entry->buf[cnt] = '\0'; __buffer_unlock_commit(buffer, event); written = cnt; *fpos += written; out_unlock: for (i = 0; i < nr_pages; i++){ kunmap_atomic(map_page[i]); put_page(pages[i]); } out: return written; } static int tracing_clock_show(struct seq_file *m, void *v) { struct trace_array *tr = m->private; int i; for (i = 0; i < ARRAY_SIZE(trace_clocks); i++) seq_printf(m, "%s%s%s%s", i ? " " : "", i == tr->clock_id ? "[" : "", trace_clocks[i].name, i == tr->clock_id ? "]" : ""); seq_putc(m, '\n'); return 0; } static ssize_t tracing_clock_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *fpos) { struct seq_file *m = filp->private_data; struct trace_array *tr = m->private; char buf[64]; const char *clockstr; int i; if (cnt >= sizeof(buf)) return -EINVAL; if (copy_from_user(&buf, ubuf, cnt)) return -EFAULT; buf[cnt] = 0; clockstr = strstrip(buf); for (i = 0; i < ARRAY_SIZE(trace_clocks); i++) { if (strcmp(trace_clocks[i].name, clockstr) == 0) break; } if (i == ARRAY_SIZE(trace_clocks)) return -EINVAL; mutex_lock(&trace_types_lock); tr->clock_id = i; ring_buffer_set_clock(tr->trace_buffer.buffer, trace_clocks[i].func); /* * New clock may not be consistent with the previous clock. * Reset the buffer so that it doesn't have incomparable timestamps. */ tracing_reset_online_cpus(&global_trace.trace_buffer); #ifdef CONFIG_TRACER_MAX_TRACE if (tr->flags & TRACE_ARRAY_FL_GLOBAL && tr->max_buffer.buffer) ring_buffer_set_clock(tr->max_buffer.buffer, trace_clocks[i].func); tracing_reset_online_cpus(&global_trace.max_buffer); #endif mutex_unlock(&trace_types_lock); *fpos += cnt; return cnt; } static int tracing_clock_open(struct inode *inode, struct file *file) { if (tracing_disabled) return -ENODEV; return single_open(file, tracing_clock_show, inode->i_private); } struct ftrace_buffer_info { struct trace_iterator iter; void *spare; unsigned int read; }; #ifdef CONFIG_TRACER_SNAPSHOT static int tracing_snapshot_open(struct inode *inode, struct file *file) { struct trace_cpu *tc = inode->i_private; struct trace_iterator *iter; struct seq_file *m; int ret = 0; if (file->f_mode & FMODE_READ) { iter = __tracing_open(inode, file, true); if (IS_ERR(iter)) ret = PTR_ERR(iter); } else { /* Writes still need the seq_file to hold the private data */ m = kzalloc(sizeof(*m), GFP_KERNEL); if (!m) return -ENOMEM; iter = kzalloc(sizeof(*iter), GFP_KERNEL); if (!iter) { kfree(m); return -ENOMEM; } iter->tr = tc->tr; iter->trace_buffer = &tc->tr->max_buffer; iter->cpu_file = tc->cpu; m->private = iter; file->private_data = m; } return ret; } static ssize_t tracing_snapshot_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *ppos) { struct seq_file *m = filp->private_data; struct trace_iterator *iter = m->private; struct trace_array *tr = iter->tr; unsigned long val; int ret; ret = tracing_update_buffers(); if (ret < 0) return ret; ret = kstrtoul_from_user(ubuf, cnt, 10, &val); if (ret) return ret; mutex_lock(&trace_types_lock); if (tr->current_trace->use_max_tr) { ret = -EBUSY; goto out; } switch (val) { case 0: if (iter->cpu_file != RING_BUFFER_ALL_CPUS) { ret = -EINVAL; break; } if (tr->allocated_snapshot) free_snapshot(tr); break; case 1: /* Only allow per-cpu swap if the ring buffer supports it */ #ifndef CONFIG_RING_BUFFER_ALLOW_SWAP if (iter->cpu_file != RING_BUFFER_ALL_CPUS) { ret = -EINVAL; break; } #endif if (!tr->allocated_snapshot) { ret = alloc_snapshot(tr); if (ret < 0) break; } local_irq_disable(); /* Now, we're going to swap */ if (iter->cpu_file == RING_BUFFER_ALL_CPUS) update_max_tr(tr, current, smp_processor_id()); else update_max_tr_single(tr, current, iter->cpu_file); local_irq_enable(); break; default: if (tr->allocated_snapshot) { if (iter->cpu_file == RING_BUFFER_ALL_CPUS) tracing_reset_online_cpus(&tr->max_buffer); else tracing_reset(&tr->max_buffer, iter->cpu_file); } break; } if (ret >= 0) { *ppos += cnt; ret = cnt; } out: mutex_unlock(&trace_types_lock); return ret; } static int tracing_snapshot_release(struct inode *inode, struct file *file) { struct seq_file *m = file->private_data; if (file->f_mode & FMODE_READ) return tracing_release(inode, file); /* If write only, the seq_file is just a stub */ if (m) kfree(m->private); kfree(m); return 0; } static int tracing_buffers_open(struct inode *inode, struct file *filp); static ssize_t tracing_buffers_read(struct file *filp, char __user *ubuf, size_t count, loff_t *ppos); static int tracing_buffers_release(struct inode *inode, struct file *file); static ssize_t tracing_buffers_splice_read(struct file *file, loff_t *ppos, struct pipe_inode_info *pipe, size_t len, unsigned int flags); static int snapshot_raw_open(struct inode *inode, struct file *filp) { struct ftrace_buffer_info *info; int ret; ret = tracing_buffers_open(inode, filp); if (ret < 0) return ret; info = filp->private_data; if (info->iter.trace->use_max_tr) { tracing_buffers_release(inode, filp); return -EBUSY; } info->iter.snapshot = true; info->iter.trace_buffer = &info->iter.tr->max_buffer; return ret; } #endif /* CONFIG_TRACER_SNAPSHOT */ static const struct file_operations tracing_max_lat_fops = { .open = tracing_open_generic, .read = tracing_max_lat_read, .write = tracing_max_lat_write, .llseek = generic_file_llseek, }; static const struct file_operations set_tracer_fops = { .open = tracing_open_generic, .read = tracing_set_trace_read, .write = tracing_set_trace_write, .llseek = generic_file_llseek, }; 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, .llseek = no_llseek, }; static const struct file_operations tracing_entries_fops = { .open = tracing_open_generic, .read = tracing_entries_read, .write = tracing_entries_write, .llseek = generic_file_llseek, }; static const struct file_operations tracing_total_entries_fops = { .open = tracing_open_generic, .read = tracing_total_entries_read, .llseek = generic_file_llseek, }; static const struct file_operations tracing_free_buffer_fops = { .write = tracing_free_buffer_write, .release = tracing_free_buffer_release, }; static const struct file_operations tracing_mark_fops = { .open = tracing_open_generic, .write = tracing_mark_write, .llseek = generic_file_llseek, }; static const struct file_operations trace_clock_fops = { .open = tracing_clock_open, .read = seq_read, .llseek = seq_lseek, .release = single_release, .write = tracing_clock_write, }; #ifdef CONFIG_TRACER_SNAPSHOT static const struct file_operations snapshot_fops = { .open = tracing_snapshot_open, .read = seq_read, .write = tracing_snapshot_write, .llseek = tracing_seek, .release = tracing_snapshot_release, }; static const struct file_operations snapshot_raw_fops = { .open = snapshot_raw_open, .read = tracing_buffers_read, .release = tracing_buffers_release, .splice_read = tracing_buffers_splice_read, .llseek = no_llseek, }; #endif /* CONFIG_TRACER_SNAPSHOT */ static int tracing_buffers_open(struct inode *inode, struct file *filp) { struct trace_cpu *tc = inode->i_private; struct trace_array *tr = tc->tr; struct ftrace_buffer_info *info; if (tracing_disabled) return -ENODEV; info = kzalloc(sizeof(*info), GFP_KERNEL); if (!info) return -ENOMEM; mutex_lock(&trace_types_lock); tr->ref++; info->iter.tr = tr; info->iter.cpu_file = tc->cpu; info->iter.trace = tr->current_trace; info->iter.trace_buffer = &tr->trace_buffer; info->spare = NULL; /* Force reading ring buffer for first read */ info->read = (unsigned int)-1; filp->private_data = info; mutex_unlock(&trace_types_lock); return nonseekable_open(inode, filp); } static unsigned int tracing_buffers_poll(struct file *filp, poll_table *poll_table) { struct ftrace_buffer_info *info = filp->private_data; struct trace_iterator *iter = &info->iter; return trace_poll(iter, filp, poll_table); } 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; struct trace_iterator *iter = &info->iter; ssize_t ret; ssize_t size; if (!count) return 0; mutex_lock(&trace_types_lock); #ifdef CONFIG_TRACER_MAX_TRACE if (iter->snapshot && iter->tr->current_trace->use_max_tr) { size = -EBUSY; goto out_unlock; } #endif if (!info->spare) info->spare = ring_buffer_alloc_read_page(iter->trace_buffer->buffer, iter->cpu_file); size = -ENOMEM; if (!info->spare) goto out_unlock; /* Do we have previous read data to read? */ if (info->read < PAGE_SIZE) goto read; again: trace_access_lock(iter->cpu_file); ret = ring_buffer_read_page(iter->trace_buffer->buffer, &info->spare, count, iter->cpu_file, 0); trace_access_unlock(iter->cpu_file); if (ret < 0) { if (trace_empty(iter)) { if ((filp->f_flags & O_NONBLOCK)) { size = -EAGAIN; goto out_unlock; } mutex_unlock(&trace_types_lock); iter->trace->wait_pipe(iter); mutex_lock(&trace_types_lock); if (signal_pending(current)) { size = -EINTR; goto out_unlock; } goto again; } size = 0; goto out_unlock; } info->read = 0; read: size = PAGE_SIZE - info->read; if (size > count) size = count; ret = copy_to_user(ubuf, info->spare + info->read, size); if (ret == size) { size = -EFAULT; goto out_unlock; } size -= ret; *ppos += size; info->read += size; out_unlock: mutex_unlock(&trace_types_lock); return size; } static int tracing_buffers_release(struct inode *inode, struct file *file) { struct ftrace_buffer_info *info = file->private_data; struct trace_iterator *iter = &info->iter; mutex_lock(&trace_types_lock); WARN_ON(!iter->tr->ref); iter->tr->ref--; if (info->spare) ring_buffer_free_read_page(iter->trace_buffer->buffer, info->spare); kfree(info); mutex_unlock(&trace_types_lock); 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 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 const 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 = generic_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 trace_iterator *iter = &info->iter; struct partial_page partial_def[PIPE_DEF_BUFFERS]; struct page *pages_def[PIPE_DEF_BUFFERS]; struct splice_pipe_desc spd = { .pages = pages_def, .partial = partial_def, .nr_pages_max = PIPE_DEF_BUFFERS, .flags = flags, .ops = &buffer_pipe_buf_ops, .spd_release = buffer_spd_release, }; struct buffer_ref *ref; int entries, size, i; ssize_t ret; mutex_lock(&trace_types_lock); #ifdef CONFIG_TRACER_MAX_TRACE if (iter->snapshot && iter->tr->current_trace->use_max_tr) { ret = -EBUSY; goto out; } #endif if (splice_grow_spd(pipe, &spd)) { ret = -ENOMEM; goto out; } if (*ppos & (PAGE_SIZE - 1)) { ret = -EINVAL; goto out; } if (len & (PAGE_SIZE - 1)) { if (len < PAGE_SIZE) { ret = -EINVAL; goto out; } len &= PAGE_MASK; } again: trace_access_lock(iter->cpu_file); entries = ring_buffer_entries_cpu(iter->trace_buffer->buffer, iter->cpu_file); for (i = 0; i < pipe->buffers && len && entries; i++, len -= PAGE_SIZE) { struct page *page; int r; ref = kzalloc(sizeof(*ref), GFP_KERNEL); if (!ref) break; ref->ref = 1; ref->buffer = iter->trace_buffer->buffer; ref->page = ring_buffer_alloc_read_page(ref->buffer, iter->cpu_file); if (!ref->page) { kfree(ref); break; } r = ring_buffer_read_page(ref->buffer, &ref->page, len, iter->cpu_file, 1); 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++; *ppos += PAGE_SIZE; entries = ring_buffer_entries_cpu(iter->trace_buffer->buffer, iter->cpu_file); } trace_access_unlock(iter->cpu_file); spd.nr_pages = i; /* did we read anything? */ if (!spd.nr_pages) { if ((file->f_flags & O_NONBLOCK) || (flags & SPLICE_F_NONBLOCK)) { ret = -EAGAIN; goto out; } mutex_unlock(&trace_types_lock); iter->trace->wait_pipe(iter); mutex_lock(&trace_types_lock); if (signal_pending(current)) { ret = -EINTR; goto out; } goto again; } ret = splice_to_pipe(pipe, &spd); splice_shrink_spd(&spd); out: mutex_unlock(&trace_types_lock); return ret; } static const struct file_operations tracing_buffers_fops = { .open = tracing_buffers_open, .read = tracing_buffers_read, .poll = tracing_buffers_poll, .release = tracing_buffers_release, .splice_read = tracing_buffers_splice_read, .llseek = no_llseek, }; static ssize_t tracing_stats_read(struct file *filp, char __user *ubuf, size_t count, loff_t *ppos) { struct trace_cpu *tc = filp->private_data; struct trace_array *tr = tc->tr; struct trace_buffer *trace_buf = &tr->trace_buffer; struct trace_seq *s; unsigned long cnt; unsigned long long t; unsigned long usec_rem; int cpu = tc->cpu; s = kmalloc(sizeof(*s), GFP_KERNEL); if (!s) return -ENOMEM; trace_seq_init(s); cnt = ring_buffer_entries_cpu(trace_buf->buffer, cpu); trace_seq_printf(s, "entries: %ld\n", cnt); cnt = ring_buffer_overrun_cpu(trace_buf->buffer, cpu); trace_seq_printf(s, "overrun: %ld\n", cnt); cnt = ring_buffer_commit_overrun_cpu(trace_buf->buffer, cpu); trace_seq_printf(s, "commit overrun: %ld\n", cnt); cnt = ring_buffer_bytes_cpu(trace_buf->buffer, cpu); trace_seq_printf(s, "bytes: %ld\n", cnt); if (trace_clocks[trace_clock_id].in_ns) { /* local or global for trace_clock */ t = ns2usecs(ring_buffer_oldest_event_ts(trace_buf->buffer, cpu)); usec_rem = do_div(t, USEC_PER_SEC); trace_seq_printf(s, "oldest event ts: %5llu.%06lu\n", t, usec_rem); t = ns2usecs(ring_buffer_time_stamp(trace_buf->buffer, cpu)); usec_rem = do_div(t, USEC_PER_SEC); trace_seq_printf(s, "now ts: %5llu.%06lu\n", t, usec_rem); } else { /* counter or tsc mode for trace_clock */ trace_seq_printf(s, "oldest event ts: %llu\n", ring_buffer_oldest_event_ts(trace_buf->buffer, cpu)); trace_seq_printf(s, "now ts: %llu\n", ring_buffer_time_stamp(trace_buf->buffer, cpu)); } cnt = ring_buffer_dropped_events_cpu(trace_buf->buffer, cpu); trace_seq_printf(s, "dropped events: %ld\n", cnt); cnt = ring_buffer_read_events_cpu(trace_buf->buffer, cpu); trace_seq_printf(s, "read events: %ld\n", cnt); count = simple_read_from_buffer(ubuf, count, ppos, s->buffer, s->len); kfree(s); return count; } static const struct file_operations tracing_stats_fops = { .open = tracing_open_generic, .read = tracing_stats_read, .llseek = generic_file_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, .llseek = generic_file_llseek, }; #endif struct dentry *tracing_init_dentry_tr(struct trace_array *tr) { static int once; if (tr->dir) return tr->dir; if (!debugfs_initialized()) return NULL; if (tr->flags & TRACE_ARRAY_FL_GLOBAL) tr->dir = debugfs_create_dir("tracing", NULL); if (!tr->dir && !once) { once = 1; pr_warning("Could not create debugfs directory 'tracing'\n"); return NULL; } return tr->dir; } struct dentry *tracing_init_dentry(void) { return tracing_init_dentry_tr(&global_trace); } static struct dentry *tracing_dentry_percpu(struct trace_array *tr, int cpu) { struct dentry *d_tracer; if (tr->percpu_dir) return tr->percpu_dir; d_tracer = tracing_init_dentry_tr(tr); if (!d_tracer) return NULL; tr->percpu_dir = debugfs_create_dir("per_cpu", d_tracer); WARN_ONCE(!tr->percpu_dir, "Could not create debugfs directory 'per_cpu/%d'\n", cpu); return tr->percpu_dir; } static void tracing_init_debugfs_percpu(struct trace_array *tr, long cpu) { struct trace_array_cpu *data = per_cpu_ptr(tr->trace_buffer.data, cpu); struct dentry *d_percpu = tracing_dentry_percpu(tr, cpu); struct dentry *d_cpu; char cpu_dir[30]; /* 30 characters should be more than enough */ if (!d_percpu) return; snprintf(cpu_dir, 30, "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 */ trace_create_file("trace_pipe", 0444, d_cpu, (void *)&data->trace_cpu, &tracing_pipe_fops); /* per cpu trace */ trace_create_file("trace", 0644, d_cpu, (void *)&data->trace_cpu, &tracing_fops); trace_create_file("trace_pipe_raw", 0444, d_cpu, (void *)&data->trace_cpu, &tracing_buffers_fops); trace_create_file("stats", 0444, d_cpu, (void *)&data->trace_cpu, &tracing_stats_fops); trace_create_file("buffer_size_kb", 0444, d_cpu, (void *)&data->trace_cpu, &tracing_entries_fops); #ifdef CONFIG_TRACER_SNAPSHOT trace_create_file("snapshot", 0644, d_cpu, (void *)&data->trace_cpu, &snapshot_fops); trace_create_file("snapshot_raw", 0444, d_cpu, (void *)&data->trace_cpu, &snapshot_raw_fops); #endif } #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 trace_array *tr; 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; int ret; ret = kstrtoul_from_user(ubuf, cnt, 10, &val); if (ret) return ret; if (val != 0 && val != 1) return -EINVAL; if (!!(topt->flags->val & topt->opt->bit) != val) { mutex_lock(&trace_types_lock); ret = __set_tracer_option(topt->tr->current_trace, topt->flags, topt->opt, !val); mutex_unlock(&trace_types_lock); if (ret) return ret; } *ppos += cnt; return cnt; } static const struct file_operations trace_options_fops = { .open = tracing_open_generic, .read = trace_options_read, .write = trace_options_write, .llseek = generic_file_llseek, }; 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) { struct trace_array *tr = &global_trace; long index = (long)filp->private_data; unsigned long val; int ret; ret = kstrtoul_from_user(ubuf, cnt, 10, &val); if (ret) return ret; if (val != 0 && val != 1) return -EINVAL; mutex_lock(&trace_types_lock); ret = set_tracer_flag(tr, 1 << index, val); mutex_unlock(&trace_types_lock); if (ret < 0) return ret; *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, .llseek = generic_file_llseek, }; struct dentry *trace_create_file(const char *name, umode_t mode, struct dentry *parent, void *data, const struct file_operations *fops) { struct dentry *ret; ret = debugfs_create_file(name, mode, parent, data, fops); if (!ret) pr_warning("Could not create debugfs '%s' entry\n", name); return ret; } static struct dentry *trace_options_init_dentry(struct trace_array *tr) { struct dentry *d_tracer; if (tr->options) return tr->options; d_tracer = tracing_init_dentry_tr(tr); if (!d_tracer) return NULL; tr->options = debugfs_create_dir("options", d_tracer); if (!tr->options) { pr_warning("Could not create debugfs directory 'options'\n"); return NULL; } return tr->options; } static void create_trace_option_file(struct trace_array *tr, struct trace_option_dentry *topt, struct tracer_flags *flags, struct tracer_opt *opt) { struct dentry *t_options; t_options = trace_options_init_dentry(tr); if (!t_options) return; topt->flags = flags; topt->opt = opt; topt->tr = tr; topt->entry = trace_create_file(opt->name, 0644, t_options, topt, &trace_options_fops); } static struct trace_option_dentry * create_trace_option_files(struct trace_array *tr, 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(tr, &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(struct trace_array *tr, const char *option, long index) { struct dentry *t_options; t_options = trace_options_init_dentry(tr); if (!t_options) return NULL; return trace_create_file(option, 0644, t_options, (void *)index, &trace_options_core_fops); } static __init void create_trace_options_dir(struct trace_array *tr) { struct dentry *t_options; int i; t_options = trace_options_init_dentry(tr); if (!t_options) return; for (i = 0; trace_options[i]; i++) create_trace_option_core_file(tr, trace_options[i], i); } static ssize_t rb_simple_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos) { struct trace_array *tr = filp->private_data; struct ring_buffer *buffer = tr->trace_buffer.buffer; char buf[64]; int r; if (buffer) r = ring_buffer_record_is_on(buffer); else r = 0; r = sprintf(buf, "%d\n", r); return simple_read_from_buffer(ubuf, cnt, ppos, buf, r); } static ssize_t rb_simple_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *ppos) { struct trace_array *tr = filp->private_data; struct ring_buffer *buffer = tr->trace_buffer.buffer; unsigned long val; int ret; ret = kstrtoul_from_user(ubuf, cnt, 10, &val); if (ret) return ret; if (buffer) { mutex_lock(&trace_types_lock); if (val) { ring_buffer_record_on(buffer); if (tr->current_trace->start) tr->current_trace->start(tr); } else { ring_buffer_record_off(buffer); if (tr->current_trace->stop) tr->current_trace->stop(tr); } mutex_unlock(&trace_types_lock); } (*ppos)++; return cnt; } static const struct file_operations rb_simple_fops = { .open = tracing_open_generic, .read = rb_simple_read, .write = rb_simple_write, .llseek = default_llseek, }; struct dentry *trace_instance_dir; static void init_tracer_debugfs(struct trace_array *tr, struct dentry *d_tracer); static void init_trace_buffers(struct trace_array *tr, struct trace_buffer *buf) { int cpu; for_each_tracing_cpu(cpu) { memset(per_cpu_ptr(buf->data, cpu), 0, sizeof(struct trace_array_cpu)); per_cpu_ptr(buf->data, cpu)->trace_cpu.cpu = cpu; per_cpu_ptr(buf->data, cpu)->trace_cpu.tr = tr; } } static int allocate_trace_buffer(struct trace_array *tr, struct trace_buffer *buf, int size) { enum ring_buffer_flags rb_flags; rb_flags = trace_flags & TRACE_ITER_OVERWRITE ? RB_FL_OVERWRITE : 0; buf->buffer = ring_buffer_alloc(size, rb_flags); if (!buf->buffer) return -ENOMEM; buf->data = alloc_percpu(struct trace_array_cpu); if (!buf->data) { ring_buffer_free(buf->buffer); return -ENOMEM; } init_trace_buffers(tr, buf); /* Allocate the first page for all buffers */ set_buffer_entries(&tr->trace_buffer, ring_buffer_size(tr->trace_buffer.buffer, 0)); return 0; } static int allocate_trace_buffers(struct trace_array *tr, int size) { int ret; ret = allocate_trace_buffer(tr, &tr->trace_buffer, size); if (ret) return ret; #ifdef CONFIG_TRACER_MAX_TRACE ret = allocate_trace_buffer(tr, &tr->max_buffer, allocate_snapshot ? size : 1); if (WARN_ON(ret)) { ring_buffer_free(tr->trace_buffer.buffer); free_percpu(tr->trace_buffer.data); return -ENOMEM; } tr->allocated_snapshot = allocate_snapshot; /* * Only the top level trace array gets its snapshot allocated * from the kernel command line. */ allocate_snapshot = false; #endif return 0; } static int new_instance_create(const char *name) { struct trace_array *tr; int ret; mutex_lock(&trace_types_lock); ret = -EEXIST; list_for_each_entry(tr, &ftrace_trace_arrays, list) { if (tr->name && strcmp(tr->name, name) == 0) goto out_unlock; } ret = -ENOMEM; tr = kzalloc(sizeof(*tr), GFP_KERNEL); if (!tr) goto out_unlock; tr->name = kstrdup(name, GFP_KERNEL); if (!tr->name) goto out_free_tr; raw_spin_lock_init(&tr->start_lock); tr->current_trace = &nop_trace; INIT_LIST_HEAD(&tr->systems); INIT_LIST_HEAD(&tr->events); if (allocate_trace_buffers(tr, trace_buf_size) < 0) goto out_free_tr; /* Holder for file callbacks */ tr->trace_cpu.cpu = RING_BUFFER_ALL_CPUS; tr->trace_cpu.tr = tr; tr->dir = debugfs_create_dir(name, trace_instance_dir); if (!tr->dir) goto out_free_tr; ret = event_trace_add_tracer(tr->dir, tr); if (ret) goto out_free_tr; init_tracer_debugfs(tr, tr->dir); list_add(&tr->list, &ftrace_trace_arrays); mutex_unlock(&trace_types_lock); return 0; out_free_tr: if (tr->trace_buffer.buffer) ring_buffer_free(tr->trace_buffer.buffer); kfree(tr->name); kfree(tr); out_unlock: mutex_unlock(&trace_types_lock); return ret; } static int instance_delete(const char *name) { struct trace_array *tr; int found = 0; int ret; mutex_lock(&trace_types_lock); ret = -ENODEV; list_for_each_entry(tr, &ftrace_trace_arrays, list) { if (tr->name && strcmp(tr->name, name) == 0) { found = 1; break; } } if (!found) goto out_unlock; ret = -EBUSY; if (tr->ref) goto out_unlock; list_del(&tr->list); event_trace_del_tracer(tr); debugfs_remove_recursive(tr->dir); free_percpu(tr->trace_buffer.data); ring_buffer_free(tr->trace_buffer.buffer); kfree(tr->name); kfree(tr); ret = 0; out_unlock: mutex_unlock(&trace_types_lock); return ret; } static int instance_mkdir (struct inode *inode, struct dentry *dentry, umode_t mode) { struct dentry *parent; int ret; /* Paranoid: Make sure the parent is the "instances" directory */ parent = hlist_entry(inode->i_dentry.first, struct dentry, d_alias); if (WARN_ON_ONCE(parent != trace_instance_dir)) return -ENOENT; /* * The inode mutex is locked, but debugfs_create_dir() will also * take the mutex. As the instances directory can not be destroyed * or changed in any other way, it is safe to unlock it, and * let the dentry try. If two users try to make the same dir at * the same time, then the new_instance_create() will determine the * winner. */ mutex_unlock(&inode->i_mutex); ret = new_instance_create(dentry->d_iname); mutex_lock(&inode->i_mutex); return ret; } static int instance_rmdir(struct inode *inode, struct dentry *dentry) { struct dentry *parent; int ret; /* Paranoid: Make sure the parent is the "instances" directory */ parent = hlist_entry(inode->i_dentry.first, struct dentry, d_alias); if (WARN_ON_ONCE(parent != trace_instance_dir)) return -ENOENT; /* The caller did a dget() on dentry */ mutex_unlock(&dentry->d_inode->i_mutex); /* * The inode mutex is locked, but debugfs_create_dir() will also * take the mutex. As the instances directory can not be destroyed * or changed in any other way, it is safe to unlock it, and * let the dentry try. If two users try to make the same dir at * the same time, then the instance_delete() will determine the * winner. */ mutex_unlock(&inode->i_mutex); ret = instance_delete(dentry->d_iname); mutex_lock_nested(&inode->i_mutex, I_MUTEX_PARENT); mutex_lock(&dentry->d_inode->i_mutex); return ret; } static const struct inode_operations instance_dir_inode_operations = { .lookup = simple_lookup, .mkdir = instance_mkdir, .rmdir = instance_rmdir, }; static __init void create_trace_instances(struct dentry *d_tracer) { trace_instance_dir = debugfs_create_dir("instances", d_tracer); if (WARN_ON(!trace_instance_dir)) return; /* Hijack the dir inode operations, to allow mkdir */ trace_instance_dir->d_inode->i_op = &instance_dir_inode_operations; } static void init_tracer_debugfs(struct trace_array *tr, struct dentry *d_tracer) { int cpu; trace_create_file("trace_options", 0644, d_tracer, tr, &tracing_iter_fops); trace_create_file("trace", 0644, d_tracer, (void *)&tr->trace_cpu, &tracing_fops); trace_create_file("trace_pipe", 0444, d_tracer, (void *)&tr->trace_cpu, &tracing_pipe_fops); trace_create_file("buffer_size_kb", 0644, d_tracer, (void *)&tr->trace_cpu, &tracing_entries_fops); trace_create_file("buffer_total_size_kb", 0444, d_tracer, tr, &tracing_total_entries_fops); trace_create_file("free_buffer", 0644, d_tracer, tr, &tracing_free_buffer_fops); trace_create_file("trace_marker", 0220, d_tracer, tr, &tracing_mark_fops); trace_create_file("trace_clock", 0644, d_tracer, tr, &trace_clock_fops); trace_create_file("tracing_on", 0644, d_tracer, tr, &rb_simple_fops); #ifdef CONFIG_TRACER_SNAPSHOT trace_create_file("snapshot", 0644, d_tracer, (void *)&tr->trace_cpu, &snapshot_fops); #endif for_each_tracing_cpu(cpu) tracing_init_debugfs_percpu(tr, cpu); } static __init int tracer_init_debugfs(void) { struct dentry *d_tracer; trace_access_lock_init(); d_tracer = tracing_init_dentry(); init_tracer_debugfs(&global_trace, d_tracer); trace_create_file("tracing_cpumask", 0644, d_tracer, &global_trace, &tracing_cpumask_fops); trace_create_file("available_tracers", 0444, d_tracer, &global_trace, &show_traces_fops); trace_create_file("current_tracer", 0644, d_tracer, &global_trace, &set_tracer_fops); #ifdef CONFIG_TRACER_MAX_TRACE trace_create_file("tracing_max_latency", 0644, d_tracer, &tracing_max_latency, &tracing_max_lat_fops); #endif trace_create_file("tracing_thresh", 0644, d_tracer, &tracing_thresh, &tracing_max_lat_fops); trace_create_file("README", 0444, d_tracer, NULL, &tracing_readme_fops); trace_create_file("saved_cmdlines", 0444, d_tracer, NULL, &tracing_saved_cmdlines_fops); #ifdef CONFIG_DYNAMIC_FTRACE trace_create_file("dyn_ftrace_total_info", 0444, d_tracer, &ftrace_update_tot_cnt, &tracing_dyn_info_fops); #endif create_trace_instances(d_tracer); create_trace_options_dir(&global_trace); return 0; } static int trace_panic_handler(struct notifier_block *this, unsigned long event, void *unused) { if (ftrace_dump_on_oops) ftrace_dump(ftrace_dump_on_oops); 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(ftrace_dump_on_oops); 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 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); } void trace_init_global_iter(struct trace_iterator *iter) { iter->tr = &global_trace; iter->trace = iter->tr->current_trace; iter->cpu_file = RING_BUFFER_ALL_CPUS; iter->trace_buffer = &global_trace.trace_buffer; } static void __ftrace_dump(bool disable_tracing, enum ftrace_dump_mode oops_dump_mode) { static arch_spinlock_t ftrace_dump_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED; /* 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 */ local_irq_save(flags); arch_spin_lock(&ftrace_dump_lock); if (dump_ran) goto out; dump_ran = 1; tracing_off(); /* Did function tracer already get disabled? */ if (ftrace_is_dead()) { printk("# WARNING: FUNCTION TRACING IS CORRUPTED\n"); printk("# MAY BE MISSING FUNCTION EVENTS\n"); } if (disable_tracing) ftrace_kill(); /* Simulate the iterator */ trace_init_global_iter(&iter); for_each_tracing_cpu(cpu) { atomic_inc(&per_cpu_ptr(iter.tr->trace_buffer.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; switch (oops_dump_mode) { case DUMP_ALL: iter.cpu_file = RING_BUFFER_ALL_CPUS; break; case DUMP_ORIG: iter.cpu_file = raw_smp_processor_id(); break; case DUMP_NONE: goto out_enable; default: printk(KERN_TRACE "Bad dumping mode, switching to all CPUs dump\n"); iter.cpu_file = RING_BUFFER_ALL_CPUS; } printk(KERN_TRACE "Dumping ftrace buffer:\n"); /* * 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 (trace_find_next_entry_inc(&iter) != NULL) { int ret; ret = print_trace_line(&iter); if (ret != TRACE_TYPE_NO_CONSUME) trace_consume(&iter); } touch_nmi_watchdog(); trace_printk_seq(&iter.seq); } if (!cnt) printk(KERN_TRACE " (ftrace buffer empty)\n"); else printk(KERN_TRACE "---------------------------------\n"); out_enable: /* Re-enable tracing if requested */ if (!disable_tracing) { trace_flags |= old_userobj; for_each_tracing_cpu(cpu) { atomic_dec(&per_cpu_ptr(iter.trace_buffer->data, cpu)->disabled); } tracing_on(); } out: arch_spin_unlock(&ftrace_dump_lock); local_irq_restore(flags); } /* By default: disable tracing after the dump */ void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { __ftrace_dump(true, oops_dump_mode); } EXPORT_SYMBOL_GPL(ftrace_dump); __init static int tracer_alloc_buffers(void) { int ring_buf_size; 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; /* Only allocate trace_printk buffers if a trace_printk exists */ if (__stop___trace_bprintk_fmt != __start___trace_bprintk_fmt) /* Must be called before global_trace.buffer is allocated */ trace_printk_init_buffers(); /* 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); raw_spin_lock_init(&global_trace.start_lock); /* TODO: make the number of buffers hot pluggable with CPUS */ if (allocate_trace_buffers(&global_trace, ring_buf_size) < 0) { printk(KERN_ERR "tracer: failed to allocate ring buffer!\n"); WARN_ON(1); goto out_free_cpumask; } if (global_trace.buffer_disabled) tracing_off(); trace_init_cmdlines(); register_tracer(&nop_trace); global_trace.current_trace = &nop_trace; /* All seems OK, enable tracing */ tracing_disabled = 0; atomic_notifier_chain_register(&panic_notifier_list, &trace_panic_notifier); register_die_notifier(&trace_die_notifier); global_trace.flags = TRACE_ARRAY_FL_GLOBAL; /* Holder for file callbacks */ global_trace.trace_cpu.cpu = RING_BUFFER_ALL_CPUS; global_trace.trace_cpu.tr = &global_trace; INIT_LIST_HEAD(&global_trace.systems); INIT_LIST_HEAD(&global_trace.events); list_add(&global_trace.list, &ftrace_trace_arrays); while (trace_boot_options) { char *option; option = strsep(&trace_boot_options, ","); trace_set_options(&global_trace, option); } return 0; out_free_cpumask: free_percpu(global_trace.trace_buffer.data); #ifdef CONFIG_TRACER_MAX_TRACE free_percpu(global_trace.max_buffer.data); #endif 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);