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Diffstat (limited to 'kernel/trace/trace.c')
| -rw-r--r-- | kernel/trace/trace.c | 4669 |
1 files changed, 4669 insertions, 0 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c new file mode 100644 index 00000000..0731e81a --- /dev/null +++ b/kernel/trace/trace.c @@ -0,0 +1,4669 @@ +/* + * ring buffer based function tracer + * + * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com> + * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com> + * + * Originally taken from the RT patch by: + * Arnaldo Carvalho de Melo <acme@redhat.com> + * + * Based on code from the latency_tracer, that is: + * Copyright (C) 2004-2006 Ingo Molnar + * Copyright (C) 2004 William Lee Irwin III + */ +#include <linux/ring_buffer.h> +#include <generated/utsrelease.h> +#include <linux/stacktrace.h> +#include <linux/writeback.h> +#include <linux/kallsyms.h> +#include <linux/seq_file.h> +#include <linux/notifier.h> +#include <linux/irqflags.h> +#include <linux/debugfs.h> +#include <linux/pagemap.h> +#include <linux/hardirq.h> +#include <linux/linkage.h> +#include <linux/uaccess.h> +#include <linux/kprobes.h> +#include <linux/ftrace.h> +#include <linux/module.h> +#include <linux/percpu.h> +#include <linux/splice.h> +#include <linux/kdebug.h> +#include <linux/string.h> +#include <linux/rwsem.h> +#include <linux/slab.h> +#include <linux/ctype.h> +#include <linux/init.h> +#include <linux/poll.h> +#include <linux/fs.h> + +#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. + */ +int ring_buffer_expanded; + +/* + * We need to change this state when a selftest is running. + * A selftest will lurk into the ring-buffer to count the + * entries inserted during the selftest although some concurrent + * insertions into the ring-buffer such as trace_printk could occurred + * at the same time, giving false positive or negative results. + */ +static bool __read_mostly tracing_selftest_running; + +/* + * If a tracer is running, we do not want to run SELFTEST. + */ +bool __read_mostly tracing_selftest_disabled; + +/* For tracers that don't implement custom flags */ +static struct tracer_opt dummy_tracer_opt[] = { + { } +}; + +static struct tracer_flags dummy_tracer_flags = { + .val = 0, + .opts = dummy_tracer_opt +}; + +static int dummy_set_flag(u32 old_flags, u32 bit, int set) +{ + return 0; +} + +/* + * Kill all tracing for good (never come back). + * It is initialized to 1 but will turn to zero if the initialization + * of the tracer is successful. But that is the only place that sets + * this back to zero. + */ +static int tracing_disabled = 1; + +DEFINE_PER_CPU(int, ftrace_cpu_disabled); + +static inline void ftrace_disable_cpu(void) +{ + preempt_disable(); + __this_cpu_inc(ftrace_cpu_disabled); +} + +static inline void ftrace_enable_cpu(void) +{ + __this_cpu_dec(ftrace_cpu_disabled); + preempt_enable(); +} + +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 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 = 1; + 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); + +unsigned long long ns2usecs(cycle_t nsec) +{ + nsec += 500; + do_div(nsec, 1000); + return nsec; +} + +/* + * The global_trace is the descriptor that holds the tracing + * buffers for the live tracing. For each CPU, it contains + * a link list of pages that will store trace entries. The + * page descriptor of the pages in the memory is used to hold + * the link list by linking the lru item in the page descriptor + * to each of the pages in the buffer per CPU. + * + * For each active CPU there is a data field that holds the + * pages for the buffer for that CPU. Each CPU has the same number + * of pages allocated for its buffer. + */ +static struct trace_array global_trace; + +static DEFINE_PER_CPU(struct trace_array_cpu, global_trace_cpu); + +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.buffer) + return trace_clock_local(); + + ts = ring_buffer_time_stamp(global_trace.buffer, cpu); + ring_buffer_normalize_time_stamp(global_trace.buffer, cpu, &ts); + + return ts; +} + +/* + * The max_tr is used to snapshot the global_trace when a maximum + * latency is reached. Some tracers will use this to store a maximum + * trace while it continues examining live traces. + * + * The buffers for the max_tr are set up the same as the global_trace. + * When a snapshot is taken, the link list of the max_tr is swapped + * with the link list of the global_trace and the buffers are reset for + * the global_trace so the tracing can continue. + */ +static struct trace_array max_tr; + +static DEFINE_PER_CPU(struct trace_array_cpu, max_tr_data); + +/* tracer_enabled is used to toggle activation of a tracer */ +static int tracer_enabled = 1; + +/** + * tracing_is_enabled - return tracer_enabled status + * + * This function is used by other tracers to know the status + * of the tracer_enabled flag. Tracers may use this function + * to know if it should enable their features when starting + * up. See irqsoff tracer for an example (start_irqsoff_tracer). + */ +int tracing_is_enabled(void) +{ + return tracer_enabled; +} + +/* + * trace_buf_size is the size in bytes that is allocated + * for a buffer. Note, the number of bytes is always rounded + * to page size. + * + * This number is purposely set to a low number of 16384. + * If the dump on oops happens, it will be much appreciated + * to not have to wait for all that output. Anyway this can be + * boot time and run time configurable. + */ +#define TRACE_BUF_SIZE_DEFAULT 1441792UL /* 16384 * 88 (sizeof(entry)) */ + +static unsigned long trace_buf_size = TRACE_BUF_SIZE_DEFAULT; + +/* trace_types holds a link list of available tracers. */ +static struct tracer *trace_types __read_mostly; + +/* current_trace points to the tracer that is currently active */ +static struct tracer *current_trace __read_mostly; + +/* + * 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 == TRACE_PIPE_ALL_CPU) { + /* 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(TRACE_PIPE_ALL_CPU). */ + 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 == TRACE_PIPE_ALL_CPU) { + 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_wait is a waitqueue for tasks blocked on trace_poll */ +static DECLARE_WAIT_QUEUE_HEAD(trace_wait); + +/* trace_flags holds trace_options default values */ +unsigned long trace_flags = TRACE_ITER_PRINT_PARENT | TRACE_ITER_PRINTK | + TRACE_ITER_ANNOTATE | TRACE_ITER_CONTEXT_INFO | TRACE_ITER_SLEEP_TIME | + TRACE_ITER_GRAPH_TIME | TRACE_ITER_RECORD_CMD | TRACE_ITER_OVERWRITE; + +static int trace_stop_count; +static DEFINE_SPINLOCK(tracing_start_lock); + +/** + * trace_wake_up - wake up tasks waiting for trace input + * + * Simply wakes up any task that is blocked on the trace_wait + * queue. These is used with trace_poll for tasks polling the trace. + */ +void trace_wake_up(void) +{ + int cpu; + + if (trace_flags & TRACE_ITER_BLOCK) + return; + /* + * The runqueue_is_locked() can fail, but this is the best we + * have for now: + */ + cpu = get_cpu(); + if (!runqueue_is_locked(cpu)) + wake_up(&trace_wait); + put_cpu(); +} + +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 threshhold; + int ret; + + if (!str) + return 0; + ret = strict_strtoul(str, 0, &threshhold); + if (ret < 0) + return 0; + tracing_thresh = threshhold * 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", + NULL +}; + +static struct { + u64 (*func)(void); + const char *name; +} trace_clocks[] = { + { trace_clock_local, "local" }, + { trace_clock_global, "global" }, +}; + +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; + void *ret; + + if (s->len <= s->readpos) + return -EBUSY; + + len = s->len - s->readpos; + if (cnt > len) + cnt = len; + ret = memcpy(buf, s->buffer + s->readpos, cnt); + if (!ret) + return -EFAULT; + + s->readpos += cnt; + return cnt; +} + +/* + * 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_array_cpu *data = tr->data[cpu]; + struct trace_array_cpu *max_data; + + max_tr.cpu = cpu; + max_tr.time_start = data->preempt_timestamp; + + max_data = max_tr.data[cpu]; + 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 = tr->buffer; + + if (trace_stop_count) + return; + + WARN_ON_ONCE(!irqs_disabled()); + if (!current_trace->use_max_tr) { + WARN_ON_ONCE(1); + return; + } + arch_spin_lock(&ftrace_max_lock); + + tr->buffer = max_tr.buffer; + max_tr.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 (trace_stop_count) + return; + + WARN_ON_ONCE(!irqs_disabled()); + if (!current_trace->use_max_tr) { + WARN_ON_ONCE(1); + return; + } + + arch_spin_lock(&ftrace_max_lock); + + ftrace_disable_cpu(); + + ret = ring_buffer_swap_cpu(max_tr.buffer, tr->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(&max_tr, _THIS_IP_, + "Failed to swap buffers due to commit in progress\n"); + } + + ftrace_enable_cpu(); + + 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 */ + +/** + * register_tracer - register a tracer with the ftrace system. + * @type - the plugin for the tracer + * + * Register a new plugin tracer. + */ +int register_tracer(struct tracer *type) +__releases(kernel_lock) +__acquires(kernel_lock) +{ + struct tracer *t; + int 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; + + +#ifdef CONFIG_FTRACE_STARTUP_TEST + if (type->selftest && !tracing_selftest_disabled) { + struct tracer *saved_tracer = current_trace; + struct trace_array *tr = &global_trace; + + /* + * 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); + + current_trace = type; + + /* If we expanded the buffers, make sure the max is expanded too */ + if (ring_buffer_expanded && type->use_max_tr) + ring_buffer_resize(max_tr.buffer, trace_buf_size); + + /* the test is responsible for initializing and enabling */ + pr_info("Testing tracer %s: ", type->name); + ret = type->selftest(type, tr); + /* the test is responsible for resetting too */ + current_trace = saved_tracer; + if (ret) { + printk(KERN_CONT "FAILED!\n"); + goto out; + } + /* Only reset on passing, to avoid touching corrupted buffers */ + tracing_reset_online_cpus(tr); + + /* Shrink the max buffer again */ + if (ring_buffer_expanded && type->use_max_tr) + ring_buffer_resize(max_tr.buffer, 1); + + printk(KERN_CONT "PASSED\n"); + } +#endif + + 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 = 1; +#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 unregister_tracer(struct tracer *type) +{ + struct tracer **t; + + mutex_lock(&trace_types_lock); + for (t = &trace_types; *t; t = &(*t)->next) { + if (*t == type) + goto found; + } + pr_info("Tracer %s not registered\n", type->name); + goto out; + + found: + *t = (*t)->next; + + if (type == current_trace && tracer_enabled) { + tracer_enabled = 0; + tracing_stop(); + if (current_trace->stop) + current_trace->stop(&global_trace); + current_trace = &nop_trace; + } +out: + mutex_unlock(&trace_types_lock); +} + +static void __tracing_reset(struct ring_buffer *buffer, int cpu) +{ + ftrace_disable_cpu(); + ring_buffer_reset_cpu(buffer, cpu); + ftrace_enable_cpu(); +} + +void tracing_reset(struct trace_array *tr, int cpu) +{ + struct ring_buffer *buffer = tr->buffer; + + ring_buffer_record_disable(buffer); + + /* Make sure all commits have finished */ + synchronize_sched(); + __tracing_reset(buffer, cpu); + + ring_buffer_record_enable(buffer); +} + +void tracing_reset_online_cpus(struct trace_array *tr) +{ + struct ring_buffer *buffer = tr->buffer; + int cpu; + + ring_buffer_record_disable(buffer); + + /* Make sure all commits have finished */ + synchronize_sched(); + + tr->time_start = ftrace_now(tr->cpu); + + for_each_online_cpu(cpu) + __tracing_reset(buffer, cpu); + + ring_buffer_record_enable(buffer); +} + +void tracing_reset_current(int cpu) +{ + tracing_reset(&global_trace, cpu); +} + +void tracing_reset_current_online_cpus(void) +{ + tracing_reset_online_cpus(&global_trace); +} + +#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 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; + + spin_lock_irqsave(&tracing_start_lock, flags); + if (--trace_stop_count) { + if (trace_stop_count < 0) { + /* Someone screwed up their debugging */ + WARN_ON_ONCE(1); + trace_stop_count = 0; + } + goto out; + } + + /* Prevent the buffers from switching */ + arch_spin_lock(&ftrace_max_lock); + + buffer = global_trace.buffer; + if (buffer) + ring_buffer_record_enable(buffer); + + buffer = max_tr.buffer; + if (buffer) + ring_buffer_record_enable(buffer); + + arch_spin_unlock(&ftrace_max_lock); + + ftrace_start(); + out: + spin_unlock_irqrestore(&tracing_start_lock, flags); +} + +/** + * tracing_stop - quick stop of the tracer + * + * Light weight way to stop tracing. Use in conjunction with + * tracing_start. + */ +void tracing_stop(void) +{ + struct ring_buffer *buffer; + unsigned long flags; + + ftrace_stop(); + spin_lock_irqsave(&tracing_start_lock, flags); + if (trace_stop_count++) + goto out; + + /* Prevent the buffers from switching */ + arch_spin_lock(&ftrace_max_lock); + + buffer = global_trace.buffer; + if (buffer) + ring_buffer_record_disable(buffer); + + buffer = max_tr.buffer; + if (buffer) + ring_buffer_record_disable(buffer); + + arch_spin_unlock(&ftrace_max_lock); + + out: + spin_unlock_irqrestore(&tracing_start_lock, flags); +} + +void trace_stop_cmdline_recording(void); + +static void trace_save_cmdline(struct task_struct *tsk) +{ + unsigned pid, idx; + + if (!tsk->pid || unlikely(tsk->pid > PID_MAX_DEFAULT)) + return; + + /* + * It's not the end of the world if we don't get + * the lock, but we also don't want to spin + * nor do we want to disable interrupts, + * so if we miss here, then better luck next time. + */ + if (!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, "<idle>"); + return; + } + + if (WARN_ON_ONCE(pid < 0)) { + strcpy(comm, "<XXX>"); + 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) || !tracer_enabled || + !tracing_is_on()) + return; + + trace_save_cmdline(tsk); +} + +void +tracing_generic_entry_update(struct trace_entry *entry, unsigned long flags, + int pc) +{ + struct task_struct *tsk = current; + + entry->preempt_count = pc & 0xff; + entry->pid = (tsk) ? tsk->pid : 0; + entry->padding = 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; +} + +static inline void +__trace_buffer_unlock_commit(struct ring_buffer *buffer, + struct ring_buffer_event *event, + unsigned long flags, int pc, + int wake) +{ + ring_buffer_unlock_commit(buffer, event); + + ftrace_trace_stack(buffer, flags, 6, pc); + ftrace_trace_userstack(buffer, flags, pc); + + if (wake) + trace_wake_up(); +} + +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, 1); +} + +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.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, 1); +} +EXPORT_SYMBOL_GPL(trace_current_buffer_unlock_commit); + +void trace_nowake_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, 0); +} +EXPORT_SYMBOL_GPL(trace_nowake_buffer_unlock_commit); + +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->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)) + ring_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 +static void __ftrace_trace_stack(struct ring_buffer *buffer, + unsigned long flags, + int skip, int pc) +{ + struct ftrace_event_call *call = &event_kernel_stack; + struct ring_buffer_event *event; + struct stack_entry *entry; + struct stack_trace trace; + + event = trace_buffer_lock_reserve(buffer, TRACE_STACK, + sizeof(*entry), flags, pc); + if (!event) + return; + entry = ring_buffer_event_data(event); + memset(&entry->caller, 0, sizeof(entry->caller)); + + trace.nr_entries = 0; + trace.max_entries = FTRACE_STACK_ENTRIES; + trace.skip = skip; + trace.entries = entry->caller; + + save_stack_trace(&trace); + if (!filter_check_discard(call, entry, buffer, event)) + ring_buffer_unlock_commit(buffer, event); +} + +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); +} + +void __trace_stack(struct trace_array *tr, unsigned long flags, int skip, + int pc) +{ + __ftrace_trace_stack(tr->buffer, flags, skip, pc); +} + +/** + * 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.buffer, flags, 3, preempt_count()); +} + +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)) + ring_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 */ + +/** + * trace_vbprintk - write binary msg to tracing buffer + * + */ +int trace_vbprintk(unsigned long ip, const char *fmt, va_list args) +{ + static arch_spinlock_t trace_buf_lock = + (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED; + static u32 trace_buf[TRACE_BUF_SIZE]; + + struct ftrace_event_call *call = &event_bprint; + struct ring_buffer_event *event; + struct ring_buffer *buffer; + struct trace_array *tr = &global_trace; + struct trace_array_cpu *data; + struct bprint_entry *entry; + unsigned long flags; + int disable; + int cpu, len = 0, size, pc; + + if (unlikely(tracing_selftest_running || tracing_disabled)) + return 0; + + /* Don't pollute graph traces with trace_vprintk internals */ + pause_graph_tracing(); + + pc = preempt_count(); + preempt_disable_notrace(); + cpu = raw_smp_processor_id(); + data = tr->data[cpu]; + + disable = atomic_inc_return(&data->disabled); + if (unlikely(disable != 1)) + goto out; + + /* Lockdep uses trace_printk for lock tracing */ + local_irq_save(flags); + arch_spin_lock(&trace_buf_lock); + len = vbin_printf(trace_buf, TRACE_BUF_SIZE, fmt, args); + + if (len > TRACE_BUF_SIZE || len < 0) + goto out_unlock; + + size = sizeof(*entry) + sizeof(u32) * len; + buffer = tr->buffer; + event = trace_buffer_lock_reserve(buffer, TRACE_BPRINT, size, + flags, pc); + if (!event) + goto out_unlock; + entry = ring_buffer_event_data(event); + entry->ip = ip; + entry->fmt = fmt; + + memcpy(entry->buf, trace_buf, sizeof(u32) * len); + if (!filter_check_discard(call, entry, buffer, event)) { + ring_buffer_unlock_commit(buffer, event); + ftrace_trace_stack(buffer, flags, 6, pc); + } + +out_unlock: + arch_spin_unlock(&trace_buf_lock); + local_irq_restore(flags); + +out: + atomic_dec_return(&data->disabled); + preempt_enable_notrace(); + unpause_graph_tracing(); + + return len; +} +EXPORT_SYMBOL_GPL(trace_vbprintk); + +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_vprintk(struct trace_array *tr, + unsigned long ip, const char *fmt, va_list args) +{ + static arch_spinlock_t trace_buf_lock = __ARCH_SPIN_LOCK_UNLOCKED; + static char trace_buf[TRACE_BUF_SIZE]; + + struct ftrace_event_call *call = &event_print; + struct ring_buffer_event *event; + struct ring_buffer *buffer; + struct trace_array_cpu *data; + int cpu, len = 0, size, pc; + struct print_entry *entry; + unsigned long irq_flags; + int disable; + + if (tracing_disabled || tracing_selftest_running) + return 0; + + pc = preempt_count(); + preempt_disable_notrace(); + cpu = raw_smp_processor_id(); + data = tr->data[cpu]; + + disable = atomic_inc_return(&data->disabled); + if (unlikely(disable != 1)) + goto out; + + pause_graph_tracing(); + raw_local_irq_save(irq_flags); + arch_spin_lock(&trace_buf_lock); + len = vsnprintf(trace_buf, TRACE_BUF_SIZE, fmt, args); + + size = sizeof(*entry) + len + 1; + buffer = tr->buffer; + event = trace_buffer_lock_reserve(buffer, TRACE_PRINT, size, + irq_flags, pc); + if (!event) + goto out_unlock; + entry = ring_buffer_event_data(event); + entry->ip = ip; + + memcpy(&entry->buf, trace_buf, len); + entry->buf[len] = '\0'; + if (!filter_check_discard(call, entry, buffer, event)) { + ring_buffer_unlock_commit(buffer, event); + ftrace_trace_stack(buffer, irq_flags, 6, pc); + } + + out_unlock: + arch_spin_unlock(&trace_buf_lock); + raw_local_irq_restore(irq_flags); + unpause_graph_tracing(); + out: + atomic_dec_return(&data->disabled); + preempt_enable_notrace(); + + return len; +} + +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) +{ + /* Don't allow ftrace to trace into the ring buffers */ + ftrace_disable_cpu(); + + iter->idx++; + if (iter->buffer_iter[iter->cpu]) + ring_buffer_read(iter->buffer_iter[iter->cpu], NULL); + + ftrace_enable_cpu(); +} + +static struct trace_entry * +peek_next_entry(struct trace_iterator *iter, int cpu, u64 *ts, + unsigned long *lost_events) +{ + struct ring_buffer_event *event; + struct ring_buffer_iter *buf_iter = iter->buffer_iter[cpu]; + + /* Don't allow ftrace to trace into the ring buffers */ + ftrace_disable_cpu(); + + if (buf_iter) + event = ring_buffer_iter_peek(buf_iter, ts); + else + event = ring_buffer_peek(iter->tr->buffer, cpu, ts, + lost_events); + + ftrace_enable_cpu(); + + return event ? ring_buffer_event_data(event) : NULL; +} + +static struct trace_entry * +__find_next_entry(struct trace_iterator *iter, int *ent_cpu, + unsigned long *missing_events, u64 *ent_ts) +{ + struct ring_buffer *buffer = iter->tr->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 cpu; + + /* + * If we are in a per_cpu trace file, don't bother by iterating over + * all cpu and peek directly. + */ + if (cpu_file > TRACE_PIPE_ALL_CPU) { + if (ring_buffer_empty_cpu(buffer, cpu_file)) + return NULL; + ent = peek_next_entry(iter, cpu_file, ent_ts, 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; + } + } + + 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) +{ + /* Don't allow ftrace to trace into the ring buffers */ + ftrace_disable_cpu(); + ring_buffer_consume(iter->tr->buffer, iter->cpu, &iter->ts, + &iter->lost_events); + ftrace_enable_cpu(); +} + +static void *s_next(struct seq_file *m, void *v, loff_t *pos) +{ + struct trace_iterator *iter = m->private; + int i = (int)*pos; + void *ent; + + 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 trace_array *tr = iter->tr; + struct ring_buffer_event *event; + struct ring_buffer_iter *buf_iter; + unsigned long entries = 0; + u64 ts; + + tr->data[cpu]->skipped_entries = 0; + + if (!iter->buffer_iter[cpu]) + return; + + buf_iter = iter->buffer_iter[cpu]; + 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->tr->time_start) + break; + entries++; + ring_buffer_read(buf_iter, NULL); + } + + tr->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; + static struct tracer *old_tracer; + int cpu_file = iter->cpu_file; + void *p = NULL; + loff_t l = 0; + int cpu; + + /* copy the tracer to avoid using a global lock all around */ + mutex_lock(&trace_types_lock); + if (unlikely(old_tracer != current_trace && current_trace)) { + old_tracer = current_trace; + *iter->trace = *current_trace; + } + mutex_unlock(&trace_types_lock); + + atomic_inc(&trace_record_cmdline_disabled); + + if (*pos != iter->pos) { + iter->ent = NULL; + iter->cpu = 0; + iter->idx = -1; + + ftrace_disable_cpu(); + + if (cpu_file == TRACE_PIPE_ALL_CPU) { + for_each_tracing_cpu(cpu) + tracing_iter_reset(iter, cpu); + } else + tracing_iter_reset(iter, cpu_file); + + ftrace_enable_cpu(); + + 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; + + atomic_dec(&trace_record_cmdline_disabled); + trace_access_unlock(iter->cpu_file); + trace_event_read_unlock(); +} + +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_func_help_header(struct seq_file *m) +{ + 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_array *tr = iter->tr; + struct trace_array_cpu *data = tr->data[tr->cpu]; + struct tracer *type = current_trace; + unsigned long entries = 0; + unsigned long total = 0; + unsigned long count; + const char *name = "preemption"; + int cpu; + + if (type) + name = type->name; + + + for_each_tracing_cpu(cpu) { + count = ring_buffer_entries_cpu(tr->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 (tr->data[cpu]->skipped_entries) { + count -= tr->data[cpu]->skipped_entries; + /* total is the same as the entries */ + total += count; + } else + total += count + + ring_buffer_overrun_cpu(tr->buffer, cpu); + entries += count; + } + + seq_printf(m, "# %s latency trace v1.1.5 on %s\n", + name, UTS_RELEASE); + seq_puts(m, "# -----------------------------------" + "---------------------------------\n"); + seq_printf(m, "# latency: %lu us, #%lu/%lu, CPU#%d |" + " (M:%s VP:%d, KP:%d, SP:%d HP:%d", + nsecs_to_usecs(data->saved_latency), + entries, + total, + tr->cpu, +#if defined(CONFIG_PREEMPT_NONE) + "server", +#elif defined(CONFIG_PREEMPT_VOLUNTARY) + "desktop", +#elif defined(CONFIG_PREEMPT) + "preempt", +#else + "unknown", +#endif + /* These are reserved for later use */ + 0, 0, 0, 0); +#ifdef CONFIG_SMP + seq_printf(m, " #P:%d)\n", num_online_cpus()); +#else + seq_puts(m, ")\n"); +#endif + seq_puts(m, "# -----------------\n"); + seq_printf(m, "# | task: %.16s-%d " + "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n", + data->comm, data->pid, data->uid, data->nice, + data->policy, data->rt_priority); + seq_puts(m, "# -----------------\n"); + + if (data->critical_start) { + seq_puts(m, "# => started at: "); + seq_print_ip_sym(&iter->seq, data->critical_start, sym_flags); + trace_print_seq(m, &iter->seq); + seq_puts(m, "\n# => ended at: "); + seq_print_ip_sym(&iter->seq, data->critical_end, sym_flags); + trace_print_seq(m, &iter->seq); + seq_puts(m, "\n#\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 (iter->tr->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) +{ + int cpu; + + /* If we are looking at one CPU buffer, only check that one */ + if (iter->cpu_file != TRACE_PIPE_ALL_CPU) { + cpu = iter->cpu_file; + if (iter->buffer_iter[cpu]) { + if (!ring_buffer_iter_empty(iter->buffer_iter[cpu])) + return 0; + } else { + if (!ring_buffer_empty_cpu(iter->tr->buffer, cpu)) + return 0; + } + return 1; + } + + for_each_tracing_cpu(cpu) { + if (iter->buffer_iter[cpu]) { + if (!ring_buffer_iter_empty(iter->buffer_iter[cpu])) + return 0; + } else { + if (!ring_buffer_empty_cpu(iter->tr->buffer, cpu)) + return 0; + } + } + + return 1; +} + +/* 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_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_default_header(struct seq_file *m) +{ + struct trace_iterator *iter = m->private; + + 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)) + print_func_help_header(m); + } +} + +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"); + } + 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) +{ + long cpu_file = (long) inode->i_private; + void *fail_ret = ERR_PTR(-ENOMEM); + struct trace_iterator *iter; + struct seq_file *m; + int cpu, ret; + + if (tracing_disabled) + return ERR_PTR(-ENODEV); + + iter = kzalloc(sizeof(*iter), GFP_KERNEL); + if (!iter) + return ERR_PTR(-ENOMEM); + + /* + * We make a copy of the current tracer to avoid concurrent + * changes on it while we are reading. + */ + mutex_lock(&trace_types_lock); + iter->trace = kzalloc(sizeof(*iter->trace), GFP_KERNEL); + if (!iter->trace) + goto fail; + + if (current_trace) + *iter->trace = *current_trace; + + if (!zalloc_cpumask_var(&iter->started, GFP_KERNEL)) + goto fail; + + if (current_trace && current_trace->print_max) + iter->tr = &max_tr; + else + iter->tr = &global_trace; + iter->pos = -1; + mutex_init(&iter->mutex); + iter->cpu_file = cpu_file; + + /* Notify the tracer early; before we stop tracing. */ + if (iter->trace && iter->trace->open) + iter->trace->open(iter); + + /* Annotate start of buffers if we had overruns */ + if (ring_buffer_overruns(iter->tr->buffer)) + iter->iter_flags |= TRACE_FILE_ANNOTATE; + + /* stop the trace while dumping */ + tracing_stop(); + + if (iter->cpu_file == TRACE_PIPE_ALL_CPU) { + for_each_tracing_cpu(cpu) { + iter->buffer_iter[cpu] = + ring_buffer_read_prepare(iter->tr->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->tr->buffer, cpu); + ring_buffer_read_prepare_sync(); + ring_buffer_read_start(iter->buffer_iter[cpu]); + tracing_iter_reset(iter, cpu); + } + + ret = seq_open(file, &tracer_seq_ops); + if (ret < 0) { + fail_ret = ERR_PTR(ret); + goto fail_buffer; + } + + m = file->private_data; + m->private = iter; + + mutex_unlock(&trace_types_lock); + + return iter; + + fail_buffer: + for_each_tracing_cpu(cpu) { + if (iter->buffer_iter[cpu]) + ring_buffer_read_finish(iter->buffer_iter[cpu]); + } + free_cpumask_var(iter->started); + tracing_start(); + fail: + mutex_unlock(&trace_types_lock); + kfree(iter->trace); + kfree(iter); + + return fail_ret; +} + +int tracing_open_generic(struct inode *inode, struct file *filp) +{ + if (tracing_disabled) + return -ENODEV; + + filp->private_data = inode->i_private; + return 0; +} + +static int tracing_release(struct inode *inode, struct file *file) +{ + struct seq_file *m = file->private_data; + struct trace_iterator *iter; + int cpu; + + if (!(file->f_mode & FMODE_READ)) + return 0; + + iter = m->private; + + mutex_lock(&trace_types_lock); + for_each_tracing_cpu(cpu) { + if (iter->buffer_iter[cpu]) + ring_buffer_read_finish(iter->buffer_iter[cpu]); + } + + if (iter->trace && iter->trace->close) + iter->trace->close(iter); + + /* reenable tracing if it was previously enabled */ + tracing_start(); + mutex_unlock(&trace_types_lock); + + seq_release(inode, file); + mutex_destroy(&iter->mutex); + free_cpumask_var(iter->started); + kfree(iter->trace); + kfree(iter); + return 0; +} + +static int tracing_open(struct inode *inode, struct file *file) +{ + struct trace_iterator *iter; + int ret = 0; + + /* If this file was open for write, then erase contents */ + if ((file->f_mode & FMODE_WRITE) && + (file->f_flags & O_TRUNC)) { + long cpu = (long) inode->i_private; + + if (cpu == TRACE_PIPE_ALL_CPU) + tracing_reset_online_cpus(&global_trace); + else + tracing_reset(&global_trace, cpu); + } + + if (file->f_mode & FMODE_READ) { + iter = __tracing_open(inode, file); + if (IS_ERR(iter)) + ret = PTR_ERR(iter); + else if (trace_flags & TRACE_ITER_LATENCY_FMT) + iter->iter_flags |= TRACE_FILE_LAT_FMT; + } + return ret; +} + +static void * +t_next(struct seq_file *m, void *v, loff_t *pos) +{ + struct tracer *t = 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) +{ + int err, cpu; + cpumask_var_t tracing_cpumask_new; + + 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(&global_trace.data[cpu]->disabled); + } + if (!cpumask_test_cpu(cpu, tracing_cpumask) && + cpumask_test_cpu(cpu, tracing_cpumask_new)) { + atomic_dec(&global_trace.data[cpu]->disabled); + } + } + 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; + u32 tracer_flags; + int i; + + mutex_lock(&trace_types_lock); + tracer_flags = current_trace->flags->val; + trace_opts = 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; +} + +static void set_tracer_flags(unsigned int mask, int enabled) +{ + /* do nothing if flag is already set */ + if (!!(trace_flags & mask) == !!enabled) + return; + + if (enabled) + trace_flags |= mask; + else + trace_flags &= ~mask; + + if (mask == TRACE_ITER_RECORD_CMD) + trace_event_enable_cmd_record(enabled); + + if (mask == TRACE_ITER_OVERWRITE) + ring_buffer_change_overwrite(global_trace.buffer, enabled); +} + +static ssize_t +tracing_trace_options_write(struct file *filp, const char __user *ubuf, + size_t cnt, loff_t *ppos) +{ + char buf[64]; + char *cmp; + int neg = 0; + int ret; + int i; + + if (cnt >= sizeof(buf)) + return -EINVAL; + + if (copy_from_user(&buf, ubuf, cnt)) + return -EFAULT; + + buf[cnt] = 0; + cmp = strstrip(buf); + + if (strncmp(cmp, "no", 2) == 0) { + neg = 1; + cmp += 2; + } + + for (i = 0; trace_options[i]; i++) { + if (strcmp(cmp, trace_options[i]) == 0) { + set_tracer_flags(1 << i, !neg); + break; + } + } + + /* If no option could be set, test the specific tracer options */ + if (!trace_options[i]) { + mutex_lock(&trace_types_lock); + ret = set_tracer_option(current_trace, cmp, neg); + mutex_unlock(&trace_types_lock); + if (ret) + return ret; + } + + *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, NULL); +} + +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 preemptirqsoff preemptoff irqsoff function sched_switch nop\n\n" + "# cat /sys/kernel/debug/tracing/current_tracer\n" + "nop\n" + "# echo sched_switch > /sys/kernel/debug/tracing/current_tracer\n" + "# cat /sys/kernel/debug/tracing/current_tracer\n" + "sched_switch\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_enabled\n" + "# cat /sys/kernel/debug/tracing/trace > /tmp/trace.txt\n" + "# echo 0 > /sys/kernel/debug/tracing/tracing_enabled\n" +; + +static ssize_t +tracing_readme_read(struct file *filp, char __user *ubuf, + size_t cnt, loff_t *ppos) +{ + return simple_read_from_buffer(ubuf, cnt, ppos, + readme_msg, strlen(readme_msg)); +} + +static const struct file_operations tracing_readme_fops = { + .open = tracing_open_generic, + .read = tracing_readme_read, + .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_ctrl_read(struct file *filp, char __user *ubuf, + size_t cnt, loff_t *ppos) +{ + char buf[64]; + int r; + + r = sprintf(buf, "%u\n", tracer_enabled); + return simple_read_from_buffer(ubuf, cnt, ppos, buf, r); +} + +static ssize_t +tracing_ctrl_write(struct file *filp, const char __user *ubuf, + size_t cnt, loff_t *ppos) +{ + struct trace_array *tr = filp->private_data; + char buf[64]; + unsigned long val; + int ret; + + if (cnt >= sizeof(buf)) + return -EINVAL; + + if (copy_from_user(&buf, ubuf, cnt)) + return -EFAULT; + + buf[cnt] = 0; + + ret = strict_strtoul(buf, 10, &val); + if (ret < 0) + return ret; + + val = !!val; + + mutex_lock(&trace_types_lock); + if (tracer_enabled ^ val) { + + /* Only need to warn if this is used to change the state */ + WARN_ONCE(1, "tracing_enabled is deprecated. Use tracing_on"); + + if (val) { + tracer_enabled = 1; + if (current_trace->start) + current_trace->start(tr); + tracing_start(); + } else { + tracer_enabled = 0; + tracing_stop(); + if (current_trace->stop) + current_trace->stop(tr); + } + } + mutex_unlock(&trace_types_lock); + + *ppos += cnt; + + return cnt; +} + +static ssize_t +tracing_set_trace_read(struct file *filp, char __user *ubuf, + size_t cnt, loff_t *ppos) +{ + char buf[MAX_TRACER_SIZE+2]; + int r; + + mutex_lock(&trace_types_lock); + if (current_trace) + r = sprintf(buf, "%s\n", current_trace->name); + else + r = sprintf(buf, "\n"); + mutex_unlock(&trace_types_lock); + + return simple_read_from_buffer(ubuf, cnt, ppos, buf, r); +} + +int tracer_init(struct tracer *t, struct trace_array *tr) +{ + tracing_reset_online_cpus(tr); + return t->init(tr); +} + +static int tracing_resize_ring_buffer(unsigned long size) +{ + int ret; + + /* + * If kernel or user changes the size of the ring buffer + * we use the size that was given, and we can forget about + * expanding it later. + */ + ring_buffer_expanded = 1; + + ret = ring_buffer_resize(global_trace.buffer, size); + if (ret < 0) + return ret; + + if (!current_trace->use_max_tr) + goto out; + + ret = ring_buffer_resize(max_tr.buffer, size); + if (ret < 0) { + int r; + + r = ring_buffer_resize(global_trace.buffer, + global_trace.entries); + if (r < 0) { + /* + * AARGH! We are left with different + * size max buffer!!!! + * The max buffer is our "snapshot" buffer. + * When a tracer needs a snapshot (one of the + * latency tracers), it swaps the max buffer + * with the saved snap shot. We succeeded to + * update the size of the main buffer, but failed to + * update the size of the max buffer. But when we tried + * to reset the main buffer to the original size, we + * failed there too. This is very unlikely to + * happen, but if it does, warn and kill all + * tracing. + */ + WARN_ON(1); + tracing_disabled = 1; + } + return ret; + } + + max_tr.entries = size; + out: + global_trace.entries = size; + + return ret; +} + + +/** + * tracing_update_buffers - used by tracing facility to expand ring buffers + * + * To save on memory when the tracing is never used on a system with it + * configured in. The ring buffers are set to a minimum size. But once + * a user starts to use the tracing facility, then they need to grow + * to their default size. + * + * This function is to be called when a tracer is about to be used. + */ +int tracing_update_buffers(void) +{ + int ret = 0; + + mutex_lock(&trace_types_lock); + if (!ring_buffer_expanded) + ret = tracing_resize_ring_buffer(trace_buf_size); + mutex_unlock(&trace_types_lock); + + return ret; +} + +struct trace_option_dentry; + +static struct trace_option_dentry * +create_trace_option_files(struct tracer *tracer); + +static void +destroy_trace_option_files(struct trace_option_dentry *topts); + +static int tracing_set_tracer(const char *buf) +{ + static struct trace_option_dentry *topts; + struct trace_array *tr = &global_trace; + struct tracer *t; + int ret = 0; + + mutex_lock(&trace_types_lock); + + if (!ring_buffer_expanded) { + ret = tracing_resize_ring_buffer(trace_buf_size); + if (ret < 0) + goto out; + ret = 0; + } + + for (t = trace_types; t; t = t->next) { + if (strcmp(t->name, buf) == 0) + break; + } + if (!t) { + ret = -EINVAL; + goto out; + } + if (t == current_trace) + goto out; + + trace_branch_disable(); + if (current_trace && current_trace->reset) + current_trace->reset(tr); + if (current_trace && current_trace->use_max_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(max_tr.buffer, 1); + max_tr.entries = 1; + } + destroy_trace_option_files(topts); + + current_trace = t; + + topts = create_trace_option_files(current_trace); + if (current_trace->use_max_tr) { + ret = ring_buffer_resize(max_tr.buffer, global_trace.entries); + if (ret < 0) + goto out; + max_tr.entries = global_trace.entries; + } + + if (t->init) { + ret = tracer_init(t, tr); + if (ret) + goto out; + } + + trace_branch_enable(tr); + out: + mutex_unlock(&trace_types_lock); + + return ret; +} + +static ssize_t +tracing_set_trace_write(struct file *filp, const char __user *ubuf, + size_t cnt, loff_t *ppos) +{ + char buf[MAX_TRACER_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; + char buf[64]; + unsigned long val; + int ret; + + if (cnt >= sizeof(buf)) + return -EINVAL; + + if (copy_from_user(&buf, ubuf, cnt)) + return -EFAULT; + + buf[cnt] = 0; + + ret = strict_strtoul(buf, 10, &val); + if (ret < 0) + return ret; + + *ptr = val * 1000; + + return cnt; +} + +static int tracing_open_pipe(struct inode *inode, struct file *filp) +{ + long cpu_file = (long) inode->i_private; + struct trace_iterator *iter; + int ret = 0; + + if (tracing_disabled) + return -ENODEV; + + mutex_lock(&trace_types_lock); + + /* create a buffer to store the information to pass to userspace */ + iter = kzalloc(sizeof(*iter), GFP_KERNEL); + if (!iter) { + ret = -ENOMEM; + goto out; + } + + /* + * We make a copy of the current tracer to avoid concurrent + * changes on it while we are reading. + */ + iter->trace = kmalloc(sizeof(*iter->trace), GFP_KERNEL); + if (!iter->trace) { + ret = -ENOMEM; + goto fail; + } + if (current_trace) + *iter->trace = *current_trace; + + if (!alloc_cpumask_var(&iter->started, GFP_KERNEL)) { + ret = -ENOMEM; + goto fail; + } + + /* trace pipe does not show start of buffer */ + cpumask_setall(iter->started); + + if (trace_flags & TRACE_ITER_LATENCY_FMT) + iter->iter_flags |= TRACE_FILE_LAT_FMT; + + iter->cpu_file = cpu_file; + iter->tr = &global_trace; + mutex_init(&iter->mutex); + filp->private_data = iter; + + if (iter->trace->pipe_open) + iter->trace->pipe_open(iter); + + 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 +tracing_poll_pipe(struct file *filp, poll_table *poll_table) +{ + struct trace_iterator *iter = filp->private_data; + + if (trace_flags & TRACE_ITER_BLOCK) { + /* + * Always select as readable when in blocking mode + */ + return POLLIN | POLLRDNORM; + } else { + if (!trace_empty(iter)) + return POLLIN | POLLRDNORM; + poll_wait(filp, &trace_wait, poll_table); + if (!trace_empty(iter)) + return POLLIN | POLLRDNORM; + + return 0; + } +} + + +void default_wait_pipe(struct trace_iterator *iter) +{ + DEFINE_WAIT(wait); + + prepare_to_wait(&trace_wait, &wait, TASK_INTERRUPTIBLE); + + if (trace_empty(iter)) + schedule(); + + finish_wait(&trace_wait, &wait); +} + +/* + * This is a make-shift waitqueue. + * A tracer might use this callback on some rare cases: + * + * 1) the current tracer might hold the runqueue lock when it wakes up + * a reader, hence a deadlock (sched, function, and function graph tracers) + * 2) the function tracers, trace all functions, we don't want + * the overhead of calling wake_up and friends + * (and tracing them too) + * + * Anyway, this is really very primitive wakeup. + */ +void poll_wait_pipe(struct trace_iterator *iter) +{ + set_current_state(TASK_INTERRUPTIBLE); + /* sleep for 100 msecs, and try again. */ + schedule_timeout(HZ / 10); +} + +/* Must be called with trace_types_lock mutex held. */ +static int tracing_wait_pipe(struct file *filp) +{ + struct trace_iterator *iter = filp->private_data; + + while (trace_empty(iter)) { + + if ((filp->f_flags & O_NONBLOCK)) { + return -EAGAIN; + } + + mutex_unlock(&iter->mutex); + + iter->trace->wait_pipe(iter); + + mutex_lock(&iter->mutex); + + if (signal_pending(current)) + return -EINTR; + + /* + * We block until we read something and tracing is disabled. + * We still block if tracing is disabled, but we have never + * read anything. This allows a user to cat this file, and + * then enable tracing. But after we have read something, + * we give an EOF when tracing is again disabled. + * + * iter->pos will be 0 if we haven't read anything. + */ + if (!tracer_enabled && iter->pos) + break; + } + + return 1; +} + +/* + * Consumer reader. + */ +static ssize_t +tracing_read_pipe(struct file *filp, char __user *ubuf, + size_t cnt, loff_t *ppos) +{ + struct trace_iterator *iter = filp->private_data; + static struct tracer *old_tracer; + ssize_t sret; + + /* return any leftover data */ + sret = trace_seq_to_user(&iter->seq, ubuf, cnt); + if (sret != -EBUSY) + return sret; + + trace_seq_init(&iter->seq); + + /* copy the tracer to avoid using a global lock all around */ + mutex_lock(&trace_types_lock); + if (unlikely(old_tracer != current_trace && current_trace)) { + old_tracer = current_trace; + *iter->trace = *current_trace; + } + mutex_unlock(&trace_types_lock); + + /* + * Avoid more than one consumer on a single file descriptor + * This is just a matter of traces coherency, the ring buffer itself + * is protected. + */ + mutex_lock(&iter->mutex); + if (iter->trace->read) { + sret = iter->trace->read(iter, filp, ubuf, cnt, ppos); + if (sret) + goto out; + } + +waitagain: + sret = tracing_wait_pipe(filp); + if (sret <= 0) + goto out; + + /* stop when tracing is finished */ + if (trace_empty(iter)) { + sret = 0; + goto out; + } + + if (cnt >= PAGE_SIZE) + cnt = PAGE_SIZE - 1; + + /* reset all but tr, trace, and overruns */ + memset(&iter->seq, 0, + sizeof(struct trace_iterator) - + offsetof(struct trace_iterator, seq)); + iter->pos = -1; + + 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. */ + .flags = flags, + .ops = &tracing_pipe_buf_ops, + .spd_release = tracing_spd_release_pipe, + }; + static struct tracer *old_tracer; + ssize_t ret; + size_t rem; + unsigned int i; + + 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(old_tracer != current_trace && current_trace)) { + old_tracer = current_trace; + *iter->trace = *current_trace; + } + mutex_unlock(&trace_types_lock); + + mutex_lock(&iter->mutex); + + if (iter->trace->splice_read) { + ret = iter->trace->splice_read(iter, filp, + ppos, pipe, len, flags); + if (ret) + goto out_err; + } + + ret = tracing_wait_pipe(filp); + if (ret <= 0) + goto out_err; + + if (!iter->ent && !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(pipe, &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_array *tr = filp->private_data; + char buf[96]; + int r; + + mutex_lock(&trace_types_lock); + if (!ring_buffer_expanded) + r = sprintf(buf, "%lu (expanded: %lu)\n", + tr->entries >> 10, + trace_buf_size >> 10); + else + r = sprintf(buf, "%lu\n", tr->entries >> 10); + mutex_unlock(&trace_types_lock); + + return simple_read_from_buffer(ubuf, cnt, ppos, buf, r); +} + +static ssize_t +tracing_entries_write(struct file *filp, const char __user *ubuf, + size_t cnt, loff_t *ppos) +{ + unsigned long val; + char buf[64]; + int ret, cpu; + + if (cnt >= sizeof(buf)) + return -EINVAL; + + if (copy_from_user(&buf, ubuf, cnt)) + return -EFAULT; + + buf[cnt] = 0; + + ret = strict_strtoul(buf, 10, &val); + if (ret < 0) + return ret; + + /* must have at least 1 entry */ + if (!val) + return -EINVAL; + + mutex_lock(&trace_types_lock); + + tracing_stop(); + + /* disable all cpu buffers */ + for_each_tracing_cpu(cpu) { + if (global_trace.data[cpu]) + atomic_inc(&global_trace.data[cpu]->disabled); + if (max_tr.data[cpu]) + atomic_inc(&max_tr.data[cpu]->disabled); + } + + /* value is in KB */ + val <<= 10; + + if (val != global_trace.entries) { + ret = tracing_resize_ring_buffer(val); + if (ret < 0) { + cnt = ret; + goto out; + } + } + + *ppos += cnt; + + /* If check pages failed, return ENOMEM */ + if (tracing_disabled) + cnt = -ENOMEM; + out: + for_each_tracing_cpu(cpu) { + if (global_trace.data[cpu]) + atomic_dec(&global_trace.data[cpu]->disabled); + if (max_tr.data[cpu]) + atomic_dec(&max_tr.data[cpu]->disabled); + } + + tracing_start(); + mutex_unlock(&trace_types_lock); + + return cnt; +} + +static int mark_printk(const char *fmt, ...) +{ + int ret; + va_list args; + va_start(args, fmt); + ret = trace_vprintk(0, fmt, args); + va_end(args); + return ret; +} + +static ssize_t +tracing_mark_write(struct file *filp, const char __user *ubuf, + size_t cnt, loff_t *fpos) +{ + char *buf; + size_t written; + + if (tracing_disabled) + return -EINVAL; + + if (cnt > TRACE_BUF_SIZE) + cnt = TRACE_BUF_SIZE; + + buf = kmalloc(cnt + 2, GFP_KERNEL); + if (buf == NULL) + return -ENOMEM; + + if (copy_from_user(buf, ubuf, cnt)) { + kfree(buf); + return -EFAULT; + } + if (buf[cnt-1] != '\n') { + buf[cnt] = '\n'; + buf[cnt+1] = '\0'; + } else + buf[cnt] = '\0'; + + written = mark_printk("%s", buf); + kfree(buf); + *fpos += written; + + /* don't tell userspace we wrote more - it might confuse them */ + if (written > cnt) + written = cnt; + + return written; +} + +static int tracing_clock_show(struct seq_file *m, void *v) +{ + int i; + + for (i = 0; i < ARRAY_SIZE(trace_clocks); i++) + seq_printf(m, + "%s%s%s%s", i ? " " : "", + i == trace_clock_id ? "[" : "", trace_clocks[i].name, + i == trace_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) +{ + 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; + + trace_clock_id = i; + + mutex_lock(&trace_types_lock); + + ring_buffer_set_clock(global_trace.buffer, trace_clocks[i].func); + if (max_tr.buffer) + ring_buffer_set_clock(max_tr.buffer, trace_clocks[i].func); + + 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, NULL); +} + +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 tracing_ctrl_fops = { + .open = tracing_open_generic, + .read = tracing_ctrl_read, + .write = tracing_ctrl_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_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, +}; + +struct ftrace_buffer_info { + struct trace_array *tr; + void *spare; + int cpu; + unsigned int read; +}; + +static int tracing_buffers_open(struct inode *inode, struct file *filp) +{ + int cpu = (int)(long)inode->i_private; + struct ftrace_buffer_info *info; + + if (tracing_disabled) + return -ENODEV; + + info = kzalloc(sizeof(*info), GFP_KERNEL); + if (!info) + return -ENOMEM; + + info->tr = &global_trace; + info->cpu = cpu; + info->spare = NULL; + /* Force reading ring buffer for first read */ + info->read = (unsigned int)-1; + + filp->private_data = info; + + return nonseekable_open(inode, filp); +} + +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; + ssize_t ret; + size_t size; + + if (!count) + return 0; + + if (!info->spare) + info->spare = ring_buffer_alloc_read_page(info->tr->buffer); + if (!info->spare) + return -ENOMEM; + + /* Do we have previous read data to read? */ + if (info->read < PAGE_SIZE) + goto read; + + trace_access_lock(info->cpu); + ret = ring_buffer_read_page(info->tr->buffer, + &info->spare, + count, + info->cpu, 0); + trace_access_unlock(info->cpu); + if (ret < 0) + return 0; + + 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) + return -EFAULT; + size -= ret; + + *ppos += size; + info->read += size; + + return size; +} + +static int tracing_buffers_release(struct inode *inode, struct file *file) +{ + struct ftrace_buffer_info *info = file->private_data; + + if (info->spare) + ring_buffer_free_read_page(info->tr->buffer, info->spare); + kfree(info); + + return 0; +} + +struct buffer_ref { + struct ring_buffer *buffer; + void *page; + int ref; +}; + +static void buffer_pipe_buf_release(struct pipe_inode_info *pipe, + struct pipe_buffer *buf) +{ + struct buffer_ref *ref = (struct buffer_ref *)buf->private; + + if (--ref->ref) + return; + + ring_buffer_free_read_page(ref->buffer, ref->page); + kfree(ref); + buf->private = 0; +} + +static int buffer_pipe_buf_steal(struct pipe_inode_info *pipe, + struct pipe_buffer *buf) +{ + return 1; +} + +static void buffer_pipe_buf_get(struct pipe_inode_info *pipe, + struct pipe_buffer *buf) +{ + struct buffer_ref *ref = (struct buffer_ref *)buf->private; + + ref->ref++; +} + +/* Pipe buffer operations for a buffer. */ +static 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 = buffer_pipe_buf_steal, + .get = buffer_pipe_buf_get, +}; + +/* + * Callback from splice_to_pipe(), if we need to release some pages + * at the end of the spd in case we error'ed out in filling the pipe. + */ +static void buffer_spd_release(struct splice_pipe_desc *spd, unsigned int i) +{ + struct buffer_ref *ref = + (struct buffer_ref *)spd->partial[i].private; + + if (--ref->ref) + return; + + ring_buffer_free_read_page(ref->buffer, ref->page); + kfree(ref); + spd->partial[i].private = 0; +} + +static ssize_t +tracing_buffers_splice_read(struct file *file, loff_t *ppos, + struct pipe_inode_info *pipe, size_t len, + unsigned int flags) +{ + struct ftrace_buffer_info *info = file->private_data; + struct partial_page partial_def[PIPE_DEF_BUFFERS]; + struct page *pages_def[PIPE_DEF_BUFFERS]; + struct splice_pipe_desc spd = { + .pages = pages_def, + .partial = partial_def, + .flags = flags, + .ops = &buffer_pipe_buf_ops, + .spd_release = buffer_spd_release, + }; + struct buffer_ref *ref; + int entries, size, i; + size_t ret; + + if (splice_grow_spd(pipe, &spd)) + return -ENOMEM; + + if (*ppos & (PAGE_SIZE - 1)) { + WARN_ONCE(1, "Ftrace: previous read must page-align\n"); + ret = -EINVAL; + goto out; + } + + if (len & (PAGE_SIZE - 1)) { + WARN_ONCE(1, "Ftrace: splice_read should page-align\n"); + if (len < PAGE_SIZE) { + ret = -EINVAL; + goto out; + } + len &= PAGE_MASK; + } + + trace_access_lock(info->cpu); + entries = ring_buffer_entries_cpu(info->tr->buffer, info->cpu); + + 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 = info->tr->buffer; + ref->page = ring_buffer_alloc_read_page(ref->buffer); + if (!ref->page) { + kfree(ref); + break; + } + + r = ring_buffer_read_page(ref->buffer, &ref->page, + len, info->cpu, 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(info->tr->buffer, info->cpu); + } + + trace_access_unlock(info->cpu); + spd.nr_pages = i; + + /* did we read anything? */ + if (!spd.nr_pages) { + if (flags & SPLICE_F_NONBLOCK) + ret = -EAGAIN; + else + ret = 0; + /* TODO: block */ + goto out; + } + + ret = splice_to_pipe(pipe, &spd); + splice_shrink_spd(pipe, &spd); +out: + return ret; +} + +static const struct file_operations tracing_buffers_fops = { + .open = tracing_buffers_open, + .read = tracing_buffers_read, + .release = tracing_buffers_release, + .splice_read = tracing_buffers_splice_read, + .llseek = no_llseek, +}; + +static ssize_t +tracing_stats_read(struct file *filp, char __user *ubuf, + size_t count, loff_t *ppos) +{ + unsigned long cpu = (unsigned long)filp->private_data; + struct trace_array *tr = &global_trace; + struct trace_seq *s; + unsigned long cnt; + + s = kmalloc(sizeof(*s), GFP_KERNEL); + if (!s) + return -ENOMEM; + + trace_seq_init(s); + + cnt = ring_buffer_entries_cpu(tr->buffer, cpu); + trace_seq_printf(s, "entries: %ld\n", cnt); + + cnt = ring_buffer_overrun_cpu(tr->buffer, cpu); + trace_seq_printf(s, "overrun: %ld\n", cnt); + + cnt = ring_buffer_commit_overrun_cpu(tr->buffer, cpu); + trace_seq_printf(s, "commit overrun: %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 + +static struct dentry *d_tracer; + +struct dentry *tracing_init_dentry(void) +{ + static int once; + + if (d_tracer) + return d_tracer; + + if (!debugfs_initialized()) + return NULL; + + d_tracer = debugfs_create_dir("tracing", NULL); + + if (!d_tracer && !once) { + once = 1; + pr_warning("Could not create debugfs directory 'tracing'\n"); + return NULL; + } + + return d_tracer; +} + +static struct dentry *d_percpu; + +struct dentry *tracing_dentry_percpu(void) +{ + static int once; + struct dentry *d_tracer; + + if (d_percpu) + return d_percpu; + + d_tracer = tracing_init_dentry(); + + if (!d_tracer) + return NULL; + + d_percpu = debugfs_create_dir("per_cpu", d_tracer); + + if (!d_percpu && !once) { + once = 1; + pr_warning("Could not create debugfs directory 'per_cpu'\n"); + return NULL; + } + + return d_percpu; +} + +static void tracing_init_debugfs_percpu(long cpu) +{ + struct dentry *d_percpu = tracing_dentry_percpu(); + struct dentry *d_cpu; + char cpu_dir[30]; /* 30 characters should be more than enough */ + + 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 *) cpu, &tracing_pipe_fops); + + /* per cpu trace */ + trace_create_file("trace", 0644, d_cpu, + (void *) cpu, &tracing_fops); + + trace_create_file("trace_pipe_raw", 0444, d_cpu, + (void *) cpu, &tracing_buffers_fops); + + trace_create_file("stats", 0444, d_cpu, + (void *) cpu, &tracing_stats_fops); +} + +#ifdef CONFIG_FTRACE_SELFTEST +/* Let selftest have access to static functions in this file */ +#include "trace_selftest.c" +#endif + +struct trace_option_dentry { + struct tracer_opt *opt; + struct tracer_flags *flags; + struct dentry *entry; +}; + +static ssize_t +trace_options_read(struct file *filp, char __user *ubuf, size_t cnt, + loff_t *ppos) +{ + struct trace_option_dentry *topt = filp->private_data; + char *buf; + + if (topt->flags->val & topt->opt->bit) + buf = "1\n"; + else + buf = "0\n"; + + return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2); +} + +static ssize_t +trace_options_write(struct file *filp, const char __user *ubuf, size_t cnt, + loff_t *ppos) +{ + struct trace_option_dentry *topt = filp->private_data; + unsigned long val; + char buf[64]; + int ret; + + if (cnt >= sizeof(buf)) + return -EINVAL; + + if (copy_from_user(&buf, ubuf, cnt)) + return -EFAULT; + + buf[cnt] = 0; + + ret = strict_strtoul(buf, 10, &val); + if (ret < 0) + return ret; + + if (val != 0 && val != 1) + return -EINVAL; + + if (!!(topt->flags->val & topt->opt->bit) != val) { + mutex_lock(&trace_types_lock); + ret = __set_tracer_option(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) +{ + long index = (long)filp->private_data; + char buf[64]; + unsigned long val; + int ret; + + if (cnt >= sizeof(buf)) + return -EINVAL; + + if (copy_from_user(&buf, ubuf, cnt)) + return -EFAULT; + + buf[cnt] = 0; + + ret = strict_strtoul(buf, 10, &val); + if (ret < 0) + return ret; + + if (val != 0 && val != 1) + return -EINVAL; + set_tracer_flags(1 << index, val); + + *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, + mode_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(void) +{ + struct dentry *d_tracer; + static struct dentry *t_options; + + if (t_options) + return t_options; + + d_tracer = tracing_init_dentry(); + if (!d_tracer) + return NULL; + + t_options = debugfs_create_dir("options", d_tracer); + if (!t_options) { + pr_warning("Could not create debugfs directory 'options'\n"); + return NULL; + } + + return t_options; +} + +static void +create_trace_option_file(struct trace_option_dentry *topt, + struct tracer_flags *flags, + struct tracer_opt *opt) +{ + struct dentry *t_options; + + t_options = trace_options_init_dentry(); + if (!t_options) + return; + + topt->flags = flags; + topt->opt = opt; + + topt->entry = trace_create_file(opt->name, 0644, t_options, topt, + &trace_options_fops); + +} + +static struct trace_option_dentry * +create_trace_option_files(struct tracer *tracer) +{ + struct trace_option_dentry *topts; + struct tracer_flags *flags; + struct tracer_opt *opts; + int cnt; + + if (!tracer) + return NULL; + + flags = tracer->flags; + + if (!flags || !flags->opts) + return NULL; + + opts = flags->opts; + + for (cnt = 0; opts[cnt].name; cnt++) + ; + + topts = kcalloc(cnt + 1, sizeof(*topts), GFP_KERNEL); + if (!topts) + return NULL; + + for (cnt = 0; opts[cnt].name; cnt++) + create_trace_option_file(&topts[cnt], flags, + &opts[cnt]); + + return topts; +} + +static void +destroy_trace_option_files(struct trace_option_dentry *topts) +{ + int cnt; + + if (!topts) + return; + + for (cnt = 0; topts[cnt].opt; cnt++) { + if (topts[cnt].entry) + debugfs_remove(topts[cnt].entry); + } + + kfree(topts); +} + +static struct dentry * +create_trace_option_core_file(const char *option, long index) +{ + struct dentry *t_options; + + t_options = trace_options_init_dentry(); + 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(void) +{ + struct dentry *t_options; + int i; + + t_options = trace_options_init_dentry(); + if (!t_options) + return; + + for (i = 0; trace_options[i]; i++) + create_trace_option_core_file(trace_options[i], i); +} + +static __init int tracer_init_debugfs(void) +{ + struct dentry *d_tracer; + int cpu; + + trace_access_lock_init(); + + d_tracer = tracing_init_dentry(); + + trace_create_file("tracing_enabled", 0644, d_tracer, + &global_trace, &tracing_ctrl_fops); + + trace_create_file("trace_options", 0644, d_tracer, + NULL, &tracing_iter_fops); + + trace_create_file("tracing_cpumask", 0644, d_tracer, + NULL, &tracing_cpumask_fops); + + trace_create_file("trace", 0644, d_tracer, + (void *) TRACE_PIPE_ALL_CPU, &tracing_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("trace_pipe", 0444, d_tracer, + (void *) TRACE_PIPE_ALL_CPU, &tracing_pipe_fops); + + trace_create_file("buffer_size_kb", 0644, d_tracer, + &global_trace, &tracing_entries_fops); + + trace_create_file("trace_marker", 0220, d_tracer, + NULL, &tracing_mark_fops); + + trace_create_file("saved_cmdlines", 0444, d_tracer, + NULL, &tracing_saved_cmdlines_fops); + + trace_create_file("trace_clock", 0644, d_tracer, NULL, + &trace_clock_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_options_dir(); + + for_each_tracing_cpu(cpu) + tracing_init_debugfs_percpu(cpu); + + return 0; +} + +static int trace_panic_handler(struct notifier_block *this, + unsigned long event, void *unused) +{ + if (ftrace_dump_on_oops) + ftrace_dump(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 = current_trace; + iter->cpu_file = TRACE_PIPE_ALL_CPU; +} + +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(); + + if (disable_tracing) + ftrace_kill(); + + trace_init_global_iter(&iter); + + for_each_tracing_cpu(cpu) { + atomic_inc(&iter.tr->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; + + /* Simulate the iterator */ + iter.tr = &global_trace; + iter.trace = current_trace; + + switch (oops_dump_mode) { + case DUMP_ALL: + iter.cpu_file = TRACE_PIPE_ALL_CPU; + 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 = TRACE_PIPE_ALL_CPU; + } + + 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); + } + + 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(&iter.tr->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); +} + +__init static int tracer_alloc_buffers(void) +{ + int ring_buf_size; + enum ring_buffer_flags rb_flags; + int i; + int ret = -ENOMEM; + + + if (!alloc_cpumask_var(&tracing_buffer_mask, GFP_KERNEL)) + goto out; + + if (!alloc_cpumask_var(&tracing_cpumask, GFP_KERNEL)) + goto out_free_buffer_mask; + + /* 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; + + rb_flags = trace_flags & TRACE_ITER_OVERWRITE ? RB_FL_OVERWRITE : 0; + + cpumask_copy(tracing_buffer_mask, cpu_possible_mask); + cpumask_copy(tracing_cpumask, cpu_all_mask); + + /* TODO: make the number of buffers hot pluggable with CPUS */ + global_trace.buffer = ring_buffer_alloc(ring_buf_size, rb_flags); + if (!global_trace.buffer) { + printk(KERN_ERR "tracer: failed to allocate ring buffer!\n"); + WARN_ON(1); + goto out_free_cpumask; + } + global_trace.entries = ring_buffer_size(global_trace.buffer); + + +#ifdef CONFIG_TRACER_MAX_TRACE + max_tr.buffer = ring_buffer_alloc(1, rb_flags); + if (!max_tr.buffer) { + printk(KERN_ERR "tracer: failed to allocate max ring buffer!\n"); + WARN_ON(1); + ring_buffer_free(global_trace.buffer); + goto out_free_cpumask; + } + max_tr.entries = 1; +#endif + + /* Allocate the first page for all buffers */ + for_each_tracing_cpu(i) { + global_trace.data[i] = &per_cpu(global_trace_cpu, i); + max_tr.data[i] = &per_cpu(max_tr_data, i); + } + + trace_init_cmdlines(); + + register_tracer(&nop_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); + + return 0; + +out_free_cpumask: + free_cpumask_var(tracing_cpumask); +out_free_buffer_mask: + free_cpumask_var(tracing_buffer_mask); +out: + return ret; +} + +__init static int clear_boot_tracer(void) +{ + /* + * The default tracer at boot buffer is an init section. + * This function is called in lateinit. If we did not + * find the boot tracer, then clear it out, to prevent + * later registration from accessing the buffer that is + * about to be freed. + */ + if (!default_bootup_tracer) + return 0; + + printk(KERN_INFO "ftrace bootup tracer '%s' not registered.\n", + default_bootup_tracer); + default_bootup_tracer = NULL; + + return 0; +} + +early_initcall(tracer_alloc_buffers); +fs_initcall(tracer_init_debugfs); +late_initcall(clear_boot_tracer); |