const char *symbol; /* symbol name */
struct ftrace_event_class class;
struct ftrace_event_call call;
- struct ftrace_event_file **files;
+ struct list_head files;
ssize_t size; /* trace entry size */
unsigned int nr_args;
struct probe_arg args[];
};
+struct event_file_link {
+ struct ftrace_event_file *file;
+ struct list_head list;
+};
+
#define SIZEOF_TRACE_PROBE(n) \
(offsetof(struct trace_probe, args) + \
(sizeof(struct probe_arg) * (n)))
goto error;
INIT_LIST_HEAD(&tp->list);
+ INIT_LIST_HEAD(&tp->files);
return tp;
error:
kfree(tp->call.name);
return NULL;
}
-static int trace_probe_nr_files(struct trace_probe *tp)
-{
- struct ftrace_event_file **file = tp->files;
- int ret = 0;
-
- if (file)
- while (*(file++))
- ret++;
-
- return ret;
-}
-
-static DEFINE_MUTEX(probe_enable_lock);
-
/*
* Enable trace_probe
* if the file is NULL, enable "perf" handler, or enable "trace" handler.
{
int ret = 0;
- mutex_lock(&probe_enable_lock);
-
if (file) {
- struct ftrace_event_file **new, **old = tp->files;
- int n = trace_probe_nr_files(tp);
+ struct event_file_link *link;
- /* 1 is for new one and 1 is for stopper */
- new = kzalloc((n + 2) * sizeof(struct ftrace_event_file *),
- GFP_KERNEL);
- if (!new) {
+ link = kmalloc(sizeof(*link), GFP_KERNEL);
+ if (!link) {
ret = -ENOMEM;
- goto out_unlock;
+ goto out;
}
- memcpy(new, old, n * sizeof(struct ftrace_event_file *));
- new[n] = file;
- /* The last one keeps a NULL */
- rcu_assign_pointer(tp->files, new);
- tp->flags |= TP_FLAG_TRACE;
+ link->file = file;
+ list_add_tail_rcu(&link->list, &tp->files);
- if (old) {
- /* Make sure the probe is done with old files */
- synchronize_sched();
- kfree(old);
- }
+ tp->flags |= TP_FLAG_TRACE;
} else
tp->flags |= TP_FLAG_PROFILE;
- if (trace_probe_is_enabled(tp) && trace_probe_is_registered(tp) &&
- !trace_probe_has_gone(tp)) {
+ if (trace_probe_is_registered(tp) && !trace_probe_has_gone(tp)) {
if (trace_probe_is_return(tp))
ret = enable_kretprobe(&tp->rp);
else
ret = enable_kprobe(&tp->rp.kp);
}
-
- out_unlock:
- mutex_unlock(&probe_enable_lock);
-
+ out:
return ret;
}
-static int
-trace_probe_file_index(struct trace_probe *tp, struct ftrace_event_file *file)
+static struct event_file_link *
+find_event_file_link(struct trace_probe *tp, struct ftrace_event_file *file)
{
- int i;
+ struct event_file_link *link;
- if (tp->files) {
- for (i = 0; tp->files[i]; i++)
- if (tp->files[i] == file)
- return i;
- }
+ list_for_each_entry(link, &tp->files, list)
+ if (link->file == file)
+ return link;
- return -1;
+ return NULL;
}
/*
{
int ret = 0;
- mutex_lock(&probe_enable_lock);
-
if (file) {
- struct ftrace_event_file **new, **old = tp->files;
- int n = trace_probe_nr_files(tp);
- int i, j;
+ struct event_file_link *link;
- if (n == 0 || trace_probe_file_index(tp, file) < 0) {
+ link = find_event_file_link(tp, file);
+ if (!link) {
ret = -EINVAL;
- goto out_unlock;
+ goto out;
}
- if (n == 1) { /* Remove the last file */
- tp->flags &= ~TP_FLAG_TRACE;
- new = NULL;
- } else {
- new = kzalloc(n * sizeof(struct ftrace_event_file *),
- GFP_KERNEL);
- if (!new) {
- ret = -ENOMEM;
- goto out_unlock;
- }
-
- /* This copy & check loop copies the NULL stopper too */
- for (i = 0, j = 0; j < n && i < n + 1; i++)
- if (old[i] != file)
- new[j++] = old[i];
- }
+ list_del_rcu(&link->list);
+ /* synchronize with kprobe_trace_func/kretprobe_trace_func */
+ synchronize_sched();
+ kfree(link);
- rcu_assign_pointer(tp->files, new);
+ if (!list_empty(&tp->files))
+ goto out;
- /* Make sure the probe is done with old files */
- synchronize_sched();
- kfree(old);
+ tp->flags &= ~TP_FLAG_TRACE;
} else
tp->flags &= ~TP_FLAG_PROFILE;
else
disable_kprobe(&tp->rp.kp);
}
-
- out_unlock:
- mutex_unlock(&probe_enable_lock);
-
+ out:
return ret;
}
static __kprobes void
kprobe_trace_func(struct trace_probe *tp, struct pt_regs *regs)
{
- struct ftrace_event_file **file = tp->files;
+ struct event_file_link *link;
- /* Note: preempt is already disabled around the kprobe handler */
- while (*file) {
- __kprobe_trace_func(tp, regs, *file);
- file++;
- }
+ list_for_each_entry_rcu(link, &tp->files, list)
+ __kprobe_trace_func(tp, regs, link->file);
}
/* Kretprobe handler */
kretprobe_trace_func(struct trace_probe *tp, struct kretprobe_instance *ri,
struct pt_regs *regs)
{
- struct ftrace_event_file **file = tp->files;
+ struct event_file_link *link;
- /* Note: preempt is already disabled around the kprobe handler */
- while (*file) {
- __kretprobe_trace_func(tp, ri, regs, *file);
- file++;
- }
+ list_for_each_entry_rcu(link, &tp->files, list)
+ __kretprobe_trace_func(tp, ri, regs, link->file);
}
/* Event entry printers */
-enum print_line_t
+static enum print_line_t
print_kprobe_event(struct trace_iterator *iter, int flags,
struct trace_event *event)
{
return TRACE_TYPE_PARTIAL_LINE;
}
-enum print_line_t
+static enum print_line_t
print_kretprobe_event(struct trace_iterator *iter, int flags,
struct trace_event *event)
{
int size, __size, dsize;
int rctx;
+ head = this_cpu_ptr(call->perf_events);
+ if (hlist_empty(head))
+ return;
+
dsize = __get_data_size(tp, regs);
__size = sizeof(*entry) + tp->size + dsize;
size = ALIGN(__size + sizeof(u32), sizeof(u64));
size -= sizeof(u32);
- if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
- "profile buffer not large enough"))
- return;
entry = perf_trace_buf_prepare(size, call->event.type, regs, &rctx);
if (!entry)
entry->ip = (unsigned long)tp->rp.kp.addr;
memset(&entry[1], 0, dsize);
store_trace_args(sizeof(*entry), tp, regs, (u8 *)&entry[1], dsize);
-
- head = this_cpu_ptr(call->perf_events);
- perf_trace_buf_submit(entry, size, rctx,
- entry->ip, 1, regs, head, NULL);
+ perf_trace_buf_submit(entry, size, rctx, 0, 1, regs, head, NULL);
}
/* Kretprobe profile handler */
int size, __size, dsize;
int rctx;
+ head = this_cpu_ptr(call->perf_events);
+ if (hlist_empty(head))
+ return;
+
dsize = __get_data_size(tp, regs);
__size = sizeof(*entry) + tp->size + dsize;
size = ALIGN(__size + sizeof(u32), sizeof(u64));
size -= sizeof(u32);
- if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
- "profile buffer not large enough"))
- return;
entry = perf_trace_buf_prepare(size, call->event.type, regs, &rctx);
if (!entry)
entry->func = (unsigned long)tp->rp.kp.addr;
entry->ret_ip = (unsigned long)ri->ret_addr;
store_trace_args(sizeof(*entry), tp, regs, (u8 *)&entry[1], dsize);
-
- head = this_cpu_ptr(call->perf_events);
- perf_trace_buf_submit(entry, size, rctx,
- entry->ret_ip, 1, regs, head, NULL);
+ perf_trace_buf_submit(entry, size, rctx, 0, 1, regs, head, NULL);
}
#endif /* CONFIG_PERF_EVENTS */
+/*
+ * called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex.
+ *
+ * kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe
+ * lockless, but we can't race with this __init function.
+ */
static __kprobes
int kprobe_register(struct ftrace_event_call *event,
enum trace_reg type, void *data)
return NULL;
}
+/*
+ * Nobody but us can call enable_trace_probe/disable_trace_probe at this
+ * stage, we can do this lockless.
+ */
static __init int kprobe_trace_self_tests_init(void)
{
int ret, warn = 0;
projects / linux-imx.git / blobdiff