#include <linux/seq_file.h>
#include <linux/notifier.h>
#include <linux/irqflags.h>
+#include <linux/irq_work.h>
#include <linux/debugfs.h>
#include <linux/pagemap.h>
#include <linux/hardirq.h>
return 0;
}
+/*
+ * To prevent the comm cache from being overwritten when no
+ * tracing is active, only save the comm when a trace event
+ * occurred.
+ */
+static DEFINE_PER_CPU(bool, trace_cmdline_save);
+
+/*
+ * When a reader is waiting for data, then this variable is
+ * set to true.
+ */
+static bool trace_wakeup_needed;
+
+static struct irq_work trace_work_wakeup;
+
/*
* Kill all tracing for good (never come back).
* It is initialized to 1 but will turn to zero if the initialization
}
__setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops);
+
+static char trace_boot_options_buf[MAX_TRACER_SIZE] __initdata;
+static char *trace_boot_options __initdata;
+
+static int __init set_trace_boot_options(char *str)
+{
+ strncpy(trace_boot_options_buf, str, MAX_TRACER_SIZE);
+ trace_boot_options = trace_boot_options_buf;
+ return 0;
+}
+__setup("trace_options=", set_trace_boot_options);
+
unsigned long long ns2usecs(cycle_t nsec)
{
nsec += 500;
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;
+ return tracing_is_on();
}
/*
static int trace_stop_count;
static DEFINE_RAW_SPINLOCK(tracing_start_lock);
-static void wakeup_work_handler(struct work_struct *work)
+/**
+ * trace_wake_up - wake up tasks waiting for trace input
+ *
+ * Schedules a delayed work to wake up any task that is blocked on the
+ * trace_wait queue. These is used with trace_poll for tasks polling the
+ * trace.
+ */
+static void trace_wake_up(struct irq_work *work)
{
- wake_up(&trace_wait);
-}
+ wake_up_all(&trace_wait);
-static DECLARE_DELAYED_WORK(wakeup_work, wakeup_work_handler);
+}
/**
* tracing_on - enable tracing buffers
}
EXPORT_SYMBOL_GPL(tracing_is_on);
-/**
- * trace_wake_up - wake up tasks waiting for trace input
- *
- * Schedules a delayed work to wake 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)
-{
- const unsigned long delay = msecs_to_jiffies(2);
-
- if (trace_flags & TRACE_ITER_BLOCK)
- return;
- schedule_delayed_work(&wakeup_work, delay);
-}
-
static int __init set_buf_size(char *str)
{
unsigned long buf_size;
if (!str)
return 0;
- ret = strict_strtoul(str, 0, &threshold);
+ ret = kstrtoul(str, 0, &threshold);
if (ret < 0)
return 0;
tracing_thresh = threshold * 1000;
static struct {
u64 (*func)(void);
const char *name;
+ int in_ns; /* is this clock in nanoseconds? */
} trace_clocks[] = {
- { trace_clock_local, "local" },
- { trace_clock_global, "global" },
- { trace_clock_counter, "counter" },
+ { trace_clock_local, "local", 1 },
+ { trace_clock_global, "global", 1 },
+ { trace_clock_counter, "counter", 0 },
+ ARCH_TRACE_CLOCKS
};
int trace_clock_id;
}
#endif /* CONFIG_TRACER_MAX_TRACE */
+static void default_wait_pipe(struct trace_iterator *iter)
+{
+ DEFINE_WAIT(wait);
+
+ prepare_to_wait(&trace_wait, &wait, TASK_INTERRUPTIBLE);
+
+ /*
+ * The events can happen in critical sections where
+ * checking a work queue can cause deadlocks.
+ * After adding a task to the queue, this flag is set
+ * only to notify events to try to wake up the queue
+ * using irq_work.
+ *
+ * We don't clear it even if the buffer is no longer
+ * empty. The flag only causes the next event to run
+ * irq_work to do the work queue wake up. The worse
+ * that can happen if we race with !trace_empty() is that
+ * an event will cause an irq_work to try to wake up
+ * an empty queue.
+ *
+ * There's no reason to protect this flag either, as
+ * the work queue and irq_work logic will do the necessary
+ * synchronization for the wake ups. The only thing
+ * that is necessary is that the wake up happens after
+ * a task has been queued. It's OK for spurious wake ups.
+ */
+ trace_wakeup_needed = true;
+
+ if (trace_empty(iter))
+ schedule();
+
+ finish_wait(&trace_wait, &wait);
+}
+
/**
* register_tracer - register a tracer with the ftrace system.
* @type - the plugin for the tracer
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);
-}
-
void tracing_reset(struct trace_array *tr, int cpu)
{
struct ring_buffer *buffer = tr->buffer;
void tracing_record_cmdline(struct task_struct *tsk)
{
- if (atomic_read(&trace_record_cmdline_disabled) || !tracer_enabled ||
- !tracing_is_on())
+ if (atomic_read(&trace_record_cmdline_disabled) || !tracing_is_on())
return;
+ if (!__this_cpu_read(trace_cmdline_save))
+ return;
+
+ __this_cpu_write(trace_cmdline_save, false);
+
trace_save_cmdline(tsk);
}
return event;
}
+void
+__buffer_unlock_commit(struct ring_buffer *buffer, struct ring_buffer_event *event)
+{
+ __this_cpu_write(trace_cmdline_save, true);
+ if (trace_wakeup_needed) {
+ trace_wakeup_needed = false;
+ /* irq_work_queue() supplies it's own memory barriers */
+ irq_work_queue(&trace_work_wakeup);
+ }
+ ring_buffer_unlock_commit(buffer, event);
+}
+
static inline void
__trace_buffer_unlock_commit(struct ring_buffer *buffer,
struct ring_buffer_event *event,
- unsigned long flags, int pc,
- int wake)
+ unsigned long flags, int pc)
{
- ring_buffer_unlock_commit(buffer, event);
+ __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);
+ __trace_buffer_unlock_commit(buffer, event, flags, pc);
}
+EXPORT_SYMBOL_GPL(trace_buffer_unlock_commit);
struct ring_buffer_event *
trace_current_buffer_lock_reserve(struct ring_buffer **current_rb,
struct ring_buffer_event *event,
unsigned long flags, int pc)
{
- __trace_buffer_unlock_commit(buffer, event, flags, pc, 1);
+ __trace_buffer_unlock_commit(buffer, event, flags, pc);
}
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)
+void trace_buffer_unlock_commit_regs(struct ring_buffer *buffer,
+ struct ring_buffer_event *event,
+ unsigned long flags, int pc,
+ struct pt_regs *regs)
{
- __trace_buffer_unlock_commit(buffer, event, flags, pc, 0);
-}
-EXPORT_SYMBOL_GPL(trace_nowake_buffer_unlock_commit);
-
-void trace_nowake_buffer_unlock_commit_regs(struct ring_buffer *buffer,
- struct ring_buffer_event *event,
- unsigned long flags, int pc,
- struct pt_regs *regs)
-{
- ring_buffer_unlock_commit(buffer, event);
+ __buffer_unlock_commit(buffer, event);
ftrace_trace_stack_regs(buffer, flags, 0, pc, regs);
ftrace_trace_userstack(buffer, flags, pc);
}
-EXPORT_SYMBOL_GPL(trace_nowake_buffer_unlock_commit_regs);
+EXPORT_SYMBOL_GPL(trace_buffer_unlock_commit_regs);
void trace_current_buffer_discard_commit(struct ring_buffer *buffer,
struct ring_buffer_event *event)
entry->parent_ip = parent_ip;
if (!filter_check_discard(call, entry, buffer, event))
- ring_buffer_unlock_commit(buffer, event);
+ __buffer_unlock_commit(buffer, event);
}
void
entry->size = trace.nr_entries;
if (!filter_check_discard(call, entry, buffer, event))
- ring_buffer_unlock_commit(buffer, event);
+ __buffer_unlock_commit(buffer, event);
out:
/* Again, don't let gcc optimize things here */
save_stack_trace_user(&trace);
if (!filter_check_discard(call, entry, buffer, event))
- ring_buffer_unlock_commit(buffer, event);
+ __buffer_unlock_commit(buffer, event);
out_drop_count:
__this_cpu_dec(user_stack_count);
return -ENOMEM;
}
+static int buffers_allocated;
+
void trace_printk_init_buffers(void)
{
- static int buffers_allocated;
-
if (buffers_allocated)
return;
pr_info("ftrace: Allocated trace_printk buffers\n");
+ /* Expand the buffers to set size */
+ tracing_update_buffers();
+
buffers_allocated = 1;
+
+ /*
+ * trace_printk_init_buffers() can be called by modules.
+ * If that happens, then we need to start cmdline recording
+ * directly here. If the global_trace.buffer is already
+ * allocated here, then this was called by module code.
+ */
+ if (global_trace.buffer)
+ tracing_start_cmdline_record();
+}
+
+void trace_printk_start_comm(void)
+{
+ /* Start tracing comms if trace printk is set */
+ if (!buffers_allocated)
+ return;
+ tracing_start_cmdline_record();
+}
+
+static void trace_printk_start_stop_comm(int enabled)
+{
+ if (!buffers_allocated)
+ return;
+
+ if (enabled)
+ tracing_start_cmdline_record();
+ else
+ tracing_stop_cmdline_record();
}
/**
memcpy(entry->buf, tbuffer, sizeof(u32) * len);
if (!filter_check_discard(call, entry, buffer, event)) {
- ring_buffer_unlock_commit(buffer, event);
+ __buffer_unlock_commit(buffer, event);
ftrace_trace_stack(buffer, flags, 6, pc);
}
memcpy(&entry->buf, tbuffer, len);
entry->buf[len] = '\0';
if (!filter_check_discard(call, entry, buffer, event)) {
- ring_buffer_unlock_commit(buffer, event);
+ __buffer_unlock_commit(buffer, event);
ftrace_trace_stack(buffer, flags, 6, pc);
}
out:
if (ring_buffer_overruns(iter->tr->buffer))
iter->iter_flags |= TRACE_FILE_ANNOTATE;
+ /* Output in nanoseconds only if we are using a clock in nanoseconds. */
+ if (trace_clocks[trace_clock_id].in_ns)
+ iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
+
/* stop the trace while dumping */
tracing_stop();
if (mask == TRACE_ITER_OVERWRITE)
ring_buffer_change_overwrite(global_trace.buffer, enabled);
+
+ if (mask == TRACE_ITER_PRINTK)
+ trace_printk_start_stop_comm(enabled);
}
-static ssize_t
-tracing_trace_options_write(struct file *filp, const char __user *ubuf,
- size_t cnt, loff_t *ppos)
+static int trace_set_options(char *option)
{
- char buf[64];
char *cmp;
int neg = 0;
- int ret;
+ int ret = 0;
int i;
- if (cnt >= sizeof(buf))
- return -EINVAL;
-
- if (copy_from_user(&buf, ubuf, cnt))
- return -EFAULT;
-
- buf[cnt] = 0;
- cmp = strstrip(buf);
+ cmp = strstrip(option);
if (strncmp(cmp, "no", 2) == 0) {
neg = 1;
mutex_lock(&trace_types_lock);
ret = set_tracer_option(current_trace, cmp, neg);
mutex_unlock(&trace_types_lock);
- if (ret)
- return ret;
}
+ return ret;
+}
+
+static ssize_t
+tracing_trace_options_write(struct file *filp, const char __user *ubuf,
+ size_t cnt, loff_t *ppos)
+{
+ char buf[64];
+
+ if (cnt >= sizeof(buf))
+ return -EINVAL;
+
+ if (copy_from_user(&buf, ubuf, cnt))
+ return -EFAULT;
+
+ trace_set_options(buf);
+
*ppos += cnt;
return cnt;
.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;
- unsigned long val;
- int ret;
-
- ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
- if (ret)
- 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)
*/
ring_buffer_expanded = 1;
+ /* May be called before buffers are initialized */
+ if (!global_trace.buffer)
+ return 0;
+
ret = ring_buffer_resize(global_trace.buffer, size, cpu);
if (ret < 0)
return ret;
if (trace_flags & TRACE_ITER_LATENCY_FMT)
iter->iter_flags |= TRACE_FILE_LAT_FMT;
+ /* Output in nanoseconds only if we are using a clock in nanoseconds. */
+ if (trace_clocks[trace_clock_id].in_ns)
+ iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
+
iter->cpu_file = cpu_file;
iter->tr = &global_trace;
mutex_init(&iter->mutex);
}
}
-
-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:
return -EINTR;
/*
- * We block until we read something and tracing is disabled.
+ * We block until we read something and tracing is enabled.
* 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,
*
* iter->pos will be 0 if we haven't read anything.
*/
- if (!tracer_enabled && iter->pos)
+ if (tracing_is_enabled() && iter->pos)
break;
}
} else
entry->buf[cnt] = '\0';
- ring_buffer_unlock_commit(buffer, event);
+ __buffer_unlock_commit(buffer, event);
written = cnt;
if (max_tr.buffer)
ring_buffer_set_clock(max_tr.buffer, trace_clocks[i].func);
+ /*
+ * New clock may not be consistent with the previous clock.
+ * Reset the buffer so that it doesn't have incomparable timestamps.
+ */
+ tracing_reset_online_cpus(&global_trace);
+ if (max_tr.buffer)
+ tracing_reset_online_cpus(&max_tr);
+
mutex_unlock(&trace_types_lock);
*fpos += cnt;
.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,
cnt = ring_buffer_bytes_cpu(tr->buffer, cpu);
trace_seq_printf(s, "bytes: %ld\n", cnt);
- t = ns2usecs(ring_buffer_oldest_event_ts(tr->buffer, cpu));
- usec_rem = do_div(t, USEC_PER_SEC);
- trace_seq_printf(s, "oldest event ts: %5llu.%06lu\n", t, usec_rem);
+ if (trace_clocks[trace_clock_id].in_ns) {
+ /* local or global for trace_clock */
+ t = ns2usecs(ring_buffer_oldest_event_ts(tr->buffer, cpu));
+ usec_rem = do_div(t, USEC_PER_SEC);
+ trace_seq_printf(s, "oldest event ts: %5llu.%06lu\n",
+ t, usec_rem);
+
+ t = ns2usecs(ring_buffer_time_stamp(tr->buffer, cpu));
+ usec_rem = do_div(t, USEC_PER_SEC);
+ trace_seq_printf(s, "now ts: %5llu.%06lu\n", t, usec_rem);
+ } else {
+ /* counter or tsc mode for trace_clock */
+ trace_seq_printf(s, "oldest event ts: %llu\n",
+ ring_buffer_oldest_event_ts(tr->buffer, cpu));
+
+ trace_seq_printf(s, "now ts: %llu\n",
+ ring_buffer_time_stamp(tr->buffer, cpu));
+ }
- t = ns2usecs(ring_buffer_time_stamp(tr->buffer, cpu));
- usec_rem = do_div(t, USEC_PER_SEC);
- trace_seq_printf(s, "now ts: %5llu.%06lu\n", t, usec_rem);
+ cnt = ring_buffer_dropped_events_cpu(tr->buffer, cpu);
+ trace_seq_printf(s, "dropped events: %ld\n", cnt);
count = simple_read_from_buffer(ubuf, count, ppos, s->buffer, s->len);
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);
/* Only allocate trace_printk buffers if a trace_printk exists */
if (__stop___trace_bprintk_fmt != __start___trace_bprintk_fmt)
+ /* Must be called before global_trace.buffer is allocated */
trace_printk_init_buffers();
/* To save memory, keep the ring buffer size to its minimum */
#endif
trace_init_cmdlines();
+ init_irq_work(&trace_work_wakeup, trace_wake_up);
register_tracer(&nop_trace);
current_trace = &nop_trace;
register_die_notifier(&trace_die_notifier);
+ while (trace_boot_options) {
+ char *option;
+
+ option = strsep(&trace_boot_options, ",");
+ trace_set_options(option);
+ }
+
return 0;
out_free_cpumask:
projects / can-eth-gw-linux.git / blobdiff