1 files changed, 213 insertions, 27 deletions

diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index 64b54a59c55b..7938f3ae93e3 100644
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -14,11 +14,25 @@
 /* must be a power of 2 */
 #define EVENT_HASHSIZE  128
 
-static DEFINE_MUTEX(trace_event_mutex);
+DECLARE_RWSEM(trace_event_mutex);
+
+DEFINE_PER_CPU(struct trace_seq, ftrace_event_seq);
+EXPORT_PER_CPU_SYMBOL(ftrace_event_seq);
+
 static struct hlist_head event_hash[EVENT_HASHSIZE] __read_mostly;
 
 static int next_event_type = __TRACE_LAST_TYPE + 1;
 
+void trace_print_seq(struct seq_file *m, struct trace_seq *s)
+{
+        int len = s->len >= PAGE_SIZE ? PAGE_SIZE - 1 : s->len;
+
+        s->buffer[len] = 0;
+        seq_puts(m, s->buffer);
+
+        trace_seq_init(s);
+}
+
 enum print_line_t trace_print_bprintk_msg_only(struct trace_iterator *iter)
 {
         struct trace_seq *s = &iter->seq;
@@ -84,6 +98,39 @@ trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
 
         return len;
 }
+EXPORT_SYMBOL_GPL(trace_seq_printf);
+
+/**
+ * trace_seq_vprintf - sequence printing of trace information
+ * @s: trace sequence descriptor
+ * @fmt: printf format string
+ *
+ * The tracer may use either sequence operations or its own
+ * copy to user routines. To simplify formating of a trace
+ * trace_seq_printf is used to store strings into a special
+ * buffer (@s). Then the output may be either used by
+ * the sequencer or pulled into another buffer.
+ */
+int
+trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args)
+{
+        int len = (PAGE_SIZE - 1) - s->len;
+        int ret;
+
+        if (!len)
+                return 0;
+
+        ret = vsnprintf(s->buffer + s->len, len, fmt, args);
+
+        /* If we can't write it all, don't bother writing anything */
+        if (ret >= len)
+                return 0;
+
+        s->len += ret;
+
+        return len;
+}
+EXPORT_SYMBOL_GPL(trace_seq_vprintf);
 
 int trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary)
 {
@@ -201,6 +248,67 @@ int trace_seq_path(struct trace_seq *s, struct path *path)
         return 0;
 }
 
+const char *
+ftrace_print_flags_seq(struct trace_seq *p, const char *delim,
+                       unsigned long flags,
+                       const struct trace_print_flags *flag_array)
+{
+        unsigned long mask;
+        const char *str;
+        const char *ret = p->buffer + p->len;
+        int i;
+
+        for (i = 0;  flag_array[i].name && flags; i++) {
+
+                mask = flag_array[i].mask;
+                if ((flags & mask) != mask)
+                        continue;
+
+                str = flag_array[i].name;
+                flags &= ~mask;
+                if (p->len && delim)
+                        trace_seq_puts(p, delim);
+                trace_seq_puts(p, str);
+        }
+
+        /* check for left over flags */
+        if (flags) {
+                if (p->len && delim)
+                        trace_seq_puts(p, delim);
+                trace_seq_printf(p, "0x%lx", flags);
+        }
+
+        trace_seq_putc(p, 0);
+
+        return ret;
+}
+EXPORT_SYMBOL(ftrace_print_flags_seq);
+
+const char *
+ftrace_print_symbols_seq(struct trace_seq *p, unsigned long val,
+                         const struct trace_print_flags *symbol_array)
+{
+        int i;
+        const char *ret = p->buffer + p->len;
+
+        for (i = 0;  symbol_array[i].name; i++) {
+
+                if (val != symbol_array[i].mask)
+                        continue;
+
+                trace_seq_puts(p, symbol_array[i].name);
+                break;
+        }
+
+        if (!p->len)
+                trace_seq_printf(p, "0x%lx", val);
+                
+        trace_seq_putc(p, 0);
+
+        return ret;
+}
+EXPORT_SYMBOL(ftrace_print_symbols_seq);
+
 #ifdef CONFIG_KRETPROBES
 static inline const char *kretprobed(const char *name)
 {
@@ -311,17 +419,20 @@ seq_print_userip_objs(const struct userstack_entry *entry, struct trace_seq *s,
 
                 if (ip == ULONG_MAX || !ret)
                         break;
-                if (i && ret)
-                        ret = trace_seq_puts(s, " <- ");
+                if (ret)
+                        ret = trace_seq_puts(s, " => ");
                 if (!ip) {
                         if (ret)
                                 ret = trace_seq_puts(s, "??");
+                        if (ret)
+                                ret = trace_seq_puts(s, "\n");
                         continue;
                 }
                 if (!ret)
                         break;
                 if (ret)
                         ret = seq_print_user_ip(s, mm, ip, sym_flags);
+                ret = trace_seq_puts(s, "\n");
         }
 
         if (mm)
@@ -455,6 +566,7 @@ static int task_state_char(unsigned long state)
  * @type: the type of event to look for
  *
  * Returns an event of type @type otherwise NULL
+ * Called with trace_event_read_lock() held.
  */
 struct trace_event *ftrace_find_event(int type)
 {
@@ -464,7 +576,7 @@ struct trace_event *ftrace_find_event(int type)
 
         key = type & (EVENT_HASHSIZE - 1);
 
-        hlist_for_each_entry_rcu(event, n, &event_hash[key], node) {
+        hlist_for_each_entry(event, n, &event_hash[key], node) {
                 if (event->type == type)
                         return event;
         }
@@ -472,6 +584,46 @@ struct trace_event *ftrace_find_event(int type)
         return NULL;
 }
 
+static LIST_HEAD(ftrace_event_list);
+
+static int trace_search_list(struct list_head **list)
+{
+        struct trace_event *e;
+        int last = __TRACE_LAST_TYPE;
+
+        if (list_empty(&ftrace_event_list)) {
+                *list = &ftrace_event_list;
+                return last + 1;
+        }
+
+        /*
+         * We used up all possible max events,
+         * lets see if somebody freed one.
+         */
+        list_for_each_entry(e, &ftrace_event_list, list) {
+                if (e->type != last + 1)
+                        break;
+                last++;
+        }
+
+        /* Did we used up all 65 thousand events??? */
+        if ((last + 1) > FTRACE_MAX_EVENT)
+                return 0;
+
+        *list = &e->list;
+        return last + 1;
+}
+
+void trace_event_read_lock(void)
+{
+        down_read(&trace_event_mutex);
+}
+
+void trace_event_read_unlock(void)
+{
+        up_read(&trace_event_mutex);
+}
+
 /**
  * register_ftrace_event - register output for an event type
  * @event: the event type to register
@@ -492,22 +644,42 @@ int register_ftrace_event(struct trace_event *event)
         unsigned key;
         int ret = 0;
 
-        mutex_lock(&trace_event_mutex);
+        down_write(&trace_event_mutex);
 
-        if (!event) {
-                ret = next_event_type++;
+        if (WARN_ON(!event))
                 goto out;
-        }
 
-        if (!event->type)
-                event->type = next_event_type++;
-        else if (event->type > __TRACE_LAST_TYPE) {
+        INIT_LIST_HEAD(&event->list);
+
+        if (!event->type) {
+                struct list_head *list = NULL;
+
+                if (next_event_type > FTRACE_MAX_EVENT) {
+
+                        event->type = trace_search_list(&list);
+                        if (!event->type)
+                                goto out;
+
+                } else {
+                        
+                        event->type = next_event_type++;
+                        list = &ftrace_event_list;
+                }
+
+                if (WARN_ON(ftrace_find_event(event->type)))
+                        goto out;
+
+                list_add_tail(&event->list, list);
+
+        } else if (event->type > __TRACE_LAST_TYPE) {
                 printk(KERN_WARNING "Need to add type to trace.h\n");
                 WARN_ON(1);
-        }
-
-        if (ftrace_find_event(event->type))
                 goto out;
+        } else {
+                /* Is this event already used */
+                if (ftrace_find_event(event->type))
+                        goto out;
+        }
 
         if (event->trace == NULL)
                 event->trace = trace_nop_print;
@@ -520,14 +692,25 @@ int register_ftrace_event(struct trace_event *event)
 
         key = event->type & (EVENT_HASHSIZE - 1);
 
-        hlist_add_head_rcu(&event->node, &event_hash[key]);
+        hlist_add_head(&event->node, &event_hash[key]);
 
         ret = event->type;
  out:
-        mutex_unlock(&trace_event_mutex);
+        up_write(&trace_event_mutex);
 
         return ret;
 }
+EXPORT_SYMBOL_GPL(register_ftrace_event);
+
+/*
+ * Used by module code with the trace_event_mutex held for write.
+ */
+int __unregister_ftrace_event(struct trace_event *event)
+{
+        hlist_del(&event->node);
+        list_del(&event->list);
+        return 0;
+}
 
 /**
  * unregister_ftrace_event - remove a no longer used event
@@ -535,12 +718,13 @@ int register_ftrace_event(struct trace_event *event)
  */
 int unregister_ftrace_event(struct trace_event *event)
 {
-        mutex_lock(&trace_event_mutex);
-        hlist_del(&event->node);
-        mutex_unlock(&trace_event_mutex);
+        down_write(&trace_event_mutex);
+        __unregister_ftrace_event(event);
+        up_write(&trace_event_mutex);
 
         return 0;
 }
+EXPORT_SYMBOL_GPL(unregister_ftrace_event);
 
 /*
  * Standard events
@@ -833,14 +1017,16 @@ static enum print_line_t trace_stack_print(struct trace_iterator *iter,
 
         trace_assign_type(field, iter->ent);
 
+        if (!trace_seq_puts(s, "<stack trace>\n"))
+                goto partial;
         for (i = 0; i < FTRACE_STACK_ENTRIES; i++) {
-                if (i) {
-                        if (!trace_seq_puts(s, " <= "))
-                                goto partial;
+                if (!field->caller[i] || (field->caller[i] == ULONG_MAX))
+                        break;
+                if (!trace_seq_puts(s, " => "))
+                        goto partial;
 
-                        if (!seq_print_ip_sym(s, field->caller[i], flags))
-                                goto partial;
-                }
+                if (!seq_print_ip_sym(s, field->caller[i], flags))
+                        goto partial;
                 if (!trace_seq_puts(s, "\n"))
                         goto partial;
         }
@@ -868,10 +1054,10 @@ static enum print_line_t trace_user_stack_print(struct trace_iterator *iter,
 
         trace_assign_type(field, iter->ent);
 
-        if (!seq_print_userip_objs(field, s, flags))
+        if (!trace_seq_puts(s, "<user stack trace>\n"))
                 goto partial;
 
-        if (!trace_seq_putc(s, '\n'))
+        if (!seq_print_userip_objs(field, s, flags))
                 goto partial;
 
         return TRACE_TYPE_HANDLED;