ftrace: Use the rcu _notrace variants for rcu_dereference_raw() and friends
[firefly-linux-kernel-4.4.55.git] / kernel / trace / ftrace.c
index 8a5c017bb50c141bfca4d8206ac2a1805d224185..6c508ff33c6206df8e028e1eab43e913565f927e 100644 (file)
 
 #define FL_GLOBAL_CONTROL_MASK (FTRACE_OPS_FL_GLOBAL | FTRACE_OPS_FL_CONTROL)
 
+#ifdef CONFIG_DYNAMIC_FTRACE
+#define INIT_REGEX_LOCK(opsname)       \
+       .regex_lock     = __MUTEX_INITIALIZER(opsname.regex_lock),
+#else
+#define INIT_REGEX_LOCK(opsname)
+#endif
+
 static struct ftrace_ops ftrace_list_end __read_mostly = {
        .func           = ftrace_stub,
        .flags          = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_STUB,
@@ -113,24 +120,34 @@ static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip);
 
 /*
  * Traverse the ftrace_global_list, invoking all entries.  The reason that we
- * can use rcu_dereference_raw() is that elements removed from this list
+ * can use rcu_dereference_raw_notrace() is that elements removed from this list
  * are simply leaked, so there is no need to interact with a grace-period
- * mechanism.  The rcu_dereference_raw() calls are needed to handle
+ * mechanism.  The rcu_dereference_raw_notrace() calls are needed to handle
  * concurrent insertions into the ftrace_global_list.
  *
  * Silly Alpha and silly pointer-speculation compiler optimizations!
  */
 #define do_for_each_ftrace_op(op, list)                        \
-       op = rcu_dereference_raw(list);                 \
+       op = rcu_dereference_raw_notrace(list);                 \
        do
 
 /*
  * Optimized for just a single item in the list (as that is the normal case).
  */
 #define while_for_each_ftrace_op(op)                           \
-       while (likely(op = rcu_dereference_raw((op)->next)) &&  \
+       while (likely(op = rcu_dereference_raw_notrace((op)->next)) &&  \
               unlikely((op) != &ftrace_list_end))
 
+static inline void ftrace_ops_init(struct ftrace_ops *ops)
+{
+#ifdef CONFIG_DYNAMIC_FTRACE
+       if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED)) {
+               mutex_init(&ops->regex_lock);
+               ops->flags |= FTRACE_OPS_FL_INITIALIZED;
+       }
+#endif
+}
+
 /**
  * ftrace_nr_registered_ops - return number of ops registered
  *
@@ -762,7 +779,7 @@ ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
        if (hlist_empty(hhd))
                return NULL;
 
-       hlist_for_each_entry_rcu(rec, hhd, node) {
+       hlist_for_each_entry_rcu_notrace(rec, hhd, node) {
                if (rec->ip == ip)
                        return rec;
        }
@@ -907,7 +924,8 @@ static void unregister_ftrace_profiler(void)
 #else
 static struct ftrace_ops ftrace_profile_ops __read_mostly = {
        .func           = function_profile_call,
-       .flags          = FTRACE_OPS_FL_RECURSION_SAFE,
+       .flags          = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
+       INIT_REGEX_LOCK(ftrace_profile_ops)
 };
 
 static int register_ftrace_profiler(void)
@@ -1103,11 +1121,10 @@ static struct ftrace_ops global_ops = {
        .func                   = ftrace_stub,
        .notrace_hash           = EMPTY_HASH,
        .filter_hash            = EMPTY_HASH,
-       .flags                  = FTRACE_OPS_FL_RECURSION_SAFE,
+       .flags                  = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
+       INIT_REGEX_LOCK(global_ops)
 };
 
-static DEFINE_MUTEX(ftrace_regex_lock);
-
 struct ftrace_page {
        struct ftrace_page      *next;
        struct dyn_ftrace       *records;
@@ -1148,7 +1165,7 @@ ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
 
        hhd = &hash->buckets[key];
 
-       hlist_for_each_entry_rcu(entry, hhd, hlist) {
+       hlist_for_each_entry_rcu_notrace(entry, hhd, hlist) {
                if (entry->ip == ip)
                        return entry;
        }
@@ -1247,6 +1264,7 @@ static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
 
 void ftrace_free_filter(struct ftrace_ops *ops)
 {
+       ftrace_ops_init(ops);
        free_ftrace_hash(ops->filter_hash);
        free_ftrace_hash(ops->notrace_hash);
 }
@@ -1404,8 +1422,8 @@ ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip)
        struct ftrace_hash *notrace_hash;
        int ret;
 
-       filter_hash = rcu_dereference_raw(ops->filter_hash);
-       notrace_hash = rcu_dereference_raw(ops->notrace_hash);
+       filter_hash = rcu_dereference_raw_notrace(ops->filter_hash);
+       notrace_hash = rcu_dereference_raw_notrace(ops->notrace_hash);
 
        if ((ftrace_hash_empty(filter_hash) ||
             ftrace_lookup_ip(filter_hash, ip)) &&
@@ -2441,7 +2459,7 @@ t_next(struct seq_file *m, void *v, loff_t *pos)
                     !ftrace_lookup_ip(ops->notrace_hash, rec->ip)) ||
 
                    ((iter->flags & FTRACE_ITER_ENABLED) &&
-                    !(rec->flags & ~FTRACE_FL_MASK))) {
+                    !(rec->flags & FTRACE_FL_ENABLED))) {
 
                        rec = NULL;
                        goto retry;
@@ -2624,6 +2642,8 @@ ftrace_regex_open(struct ftrace_ops *ops, int flag,
        struct ftrace_hash *hash;
        int ret = 0;
 
+       ftrace_ops_init(ops);
+
        if (unlikely(ftrace_disabled))
                return -ENODEV;
 
@@ -2636,28 +2656,26 @@ ftrace_regex_open(struct ftrace_ops *ops, int flag,
                return -ENOMEM;
        }
 
+       iter->ops = ops;
+       iter->flags = flag;
+
+       mutex_lock(&ops->regex_lock);
+
        if (flag & FTRACE_ITER_NOTRACE)
                hash = ops->notrace_hash;
        else
                hash = ops->filter_hash;
 
-       iter->ops = ops;
-       iter->flags = flag;
-
        if (file->f_mode & FMODE_WRITE) {
-               mutex_lock(&ftrace_lock);
                iter->hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, hash);
-               mutex_unlock(&ftrace_lock);
-
                if (!iter->hash) {
                        trace_parser_put(&iter->parser);
                        kfree(iter);
-                       return -ENOMEM;
+                       ret = -ENOMEM;
+                       goto out_unlock;
                }
        }
 
-       mutex_lock(&ftrace_regex_lock);
-
        if ((file->f_mode & FMODE_WRITE) &&
            (file->f_flags & O_TRUNC))
                ftrace_filter_reset(iter->hash);
@@ -2677,7 +2695,9 @@ ftrace_regex_open(struct ftrace_ops *ops, int flag,
                }
        } else
                file->private_data = iter;
-       mutex_unlock(&ftrace_regex_lock);
+
+ out_unlock:
+       mutex_unlock(&ops->regex_lock);
 
        return ret;
 }
@@ -2900,7 +2920,7 @@ static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip,
         * on the hash. rcu_read_lock is too dangerous here.
         */
        preempt_disable_notrace();
-       hlist_for_each_entry_rcu(entry, hhd, node) {
+       hlist_for_each_entry_rcu_notrace(entry, hhd, node) {
                if (entry->ip == ip)
                        entry->ops->func(ip, parent_ip, &entry->data);
        }
@@ -2910,6 +2930,8 @@ static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip,
 static struct ftrace_ops trace_probe_ops __read_mostly =
 {
        .func           = function_trace_probe_call,
+       .flags          = FTRACE_OPS_FL_INITIALIZED,
+       INIT_REGEX_LOCK(trace_probe_ops)
 };
 
 static int ftrace_probe_registered;
@@ -2919,8 +2941,12 @@ static void __enable_ftrace_function_probe(void)
        int ret;
        int i;
 
-       if (ftrace_probe_registered)
+       if (ftrace_probe_registered) {
+               /* still need to update the function call sites */
+               if (ftrace_enabled)
+                       ftrace_run_update_code(FTRACE_UPDATE_CALLS);
                return;
+       }
 
        for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
                struct hlist_head *hhd = &ftrace_func_hash[i];
@@ -2990,19 +3016,21 @@ register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
        if (WARN_ON(not))
                return -EINVAL;
 
-       mutex_lock(&ftrace_lock);
+       mutex_lock(&trace_probe_ops.regex_lock);
 
        hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
        if (!hash) {
                count = -ENOMEM;
-               goto out_unlock;
+               goto out;
        }
 
        if (unlikely(ftrace_disabled)) {
                count = -ENODEV;
-               goto out_unlock;
+               goto out;
        }
 
+       mutex_lock(&ftrace_lock);
+
        do_for_each_ftrace_rec(pg, rec) {
 
                if (!ftrace_match_record(rec, NULL, search, len, type))
@@ -3056,6 +3084,8 @@ register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
 
  out_unlock:
        mutex_unlock(&ftrace_lock);
+ out:
+       mutex_unlock(&trace_probe_ops.regex_lock);
        free_ftrace_hash(hash);
 
        return count;
@@ -3095,7 +3125,7 @@ __unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
                        return;
        }
 
-       mutex_lock(&ftrace_lock);
+       mutex_lock(&trace_probe_ops.regex_lock);
 
        hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
        if (!hash)
@@ -3133,6 +3163,7 @@ __unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
                        list_add(&entry->free_list, &free_list);
                }
        }
+       mutex_lock(&ftrace_lock);
        __disable_ftrace_function_probe();
        /*
         * Remove after the disable is called. Otherwise, if the last
@@ -3144,9 +3175,10 @@ __unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
                list_del(&entry->free_list);
                ftrace_free_entry(entry);
        }
+       mutex_unlock(&ftrace_lock);
                
  out_unlock:
-       mutex_unlock(&ftrace_lock);
+       mutex_unlock(&trace_probe_ops.regex_lock);
        free_ftrace_hash(hash);
 }
 
@@ -3256,18 +3288,17 @@ ftrace_regex_write(struct file *file, const char __user *ubuf,
        if (!cnt)
                return 0;
 
-       mutex_lock(&ftrace_regex_lock);
-
-       ret = -ENODEV;
-       if (unlikely(ftrace_disabled))
-               goto out_unlock;
-
        if (file->f_mode & FMODE_READ) {
                struct seq_file *m = file->private_data;
                iter = m->private;
        } else
                iter = file->private_data;
 
+       if (unlikely(ftrace_disabled))
+               return -ENODEV;
+
+       /* iter->hash is a local copy, so we don't need regex_lock */
+
        parser = &iter->parser;
        read = trace_get_user(parser, ubuf, cnt, ppos);
 
@@ -3276,14 +3307,12 @@ ftrace_regex_write(struct file *file, const char __user *ubuf,
                ret = ftrace_process_regex(iter->hash, parser->buffer,
                                           parser->idx, enable);
                trace_parser_clear(parser);
-               if (ret)
-                       goto out_unlock;
+               if (ret < 0)
+                       goto out;
        }
 
        ret = read;
-out_unlock:
-       mutex_unlock(&ftrace_regex_lock);
-
+ out:
        return ret;
 }
 
@@ -3335,16 +3364,19 @@ ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
        if (unlikely(ftrace_disabled))
                return -ENODEV;
 
+       mutex_lock(&ops->regex_lock);
+
        if (enable)
                orig_hash = &ops->filter_hash;
        else
                orig_hash = &ops->notrace_hash;
 
        hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
-       if (!hash)
-               return -ENOMEM;
+       if (!hash) {
+               ret = -ENOMEM;
+               goto out_regex_unlock;
+       }
 
-       mutex_lock(&ftrace_regex_lock);
        if (reset)
                ftrace_filter_reset(hash);
        if (buf && !ftrace_match_records(hash, buf, len)) {
@@ -3366,7 +3398,7 @@ ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
        mutex_unlock(&ftrace_lock);
 
  out_regex_unlock:
-       mutex_unlock(&ftrace_regex_lock);
+       mutex_unlock(&ops->regex_lock);
 
        free_ftrace_hash(hash);
        return ret;
@@ -3392,6 +3424,7 @@ ftrace_set_addr(struct ftrace_ops *ops, unsigned long ip, int remove,
 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
                         int remove, int reset)
 {
+       ftrace_ops_init(ops);
        return ftrace_set_addr(ops, ip, remove, reset, 1);
 }
 EXPORT_SYMBOL_GPL(ftrace_set_filter_ip);
@@ -3416,6 +3449,7 @@ ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
                       int len, int reset)
 {
+       ftrace_ops_init(ops);
        return ftrace_set_regex(ops, buf, len, reset, 1);
 }
 EXPORT_SYMBOL_GPL(ftrace_set_filter);
@@ -3434,6 +3468,7 @@ EXPORT_SYMBOL_GPL(ftrace_set_filter);
 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
                        int len, int reset)
 {
+       ftrace_ops_init(ops);
        return ftrace_set_regex(ops, buf, len, reset, 0);
 }
 EXPORT_SYMBOL_GPL(ftrace_set_notrace);
@@ -3524,6 +3559,8 @@ ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable)
 {
        char *func;
 
+       ftrace_ops_init(ops);
+
        while (buf) {
                func = strsep(&buf, ",");
                ftrace_set_regex(ops, func, strlen(func), 0, enable);
@@ -3551,10 +3588,8 @@ int ftrace_regex_release(struct inode *inode, struct file *file)
        int filter_hash;
        int ret;
 
-       mutex_lock(&ftrace_regex_lock);
        if (file->f_mode & FMODE_READ) {
                iter = m->private;
-
                seq_release(inode, file);
        } else
                iter = file->private_data;
@@ -3567,6 +3602,8 @@ int ftrace_regex_release(struct inode *inode, struct file *file)
 
        trace_parser_put(parser);
 
+       mutex_lock(&iter->ops->regex_lock);
+
        if (file->f_mode & FMODE_WRITE) {
                filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
 
@@ -3584,10 +3621,11 @@ int ftrace_regex_release(struct inode *inode, struct file *file)
 
                mutex_unlock(&ftrace_lock);
        }
+
+       mutex_unlock(&iter->ops->regex_lock);
        free_ftrace_hash(iter->hash);
        kfree(iter);
 
-       mutex_unlock(&ftrace_regex_lock);
        return 0;
 }
 
@@ -4126,7 +4164,8 @@ void __init ftrace_init(void)
 
 static struct ftrace_ops global_ops = {
        .func                   = ftrace_stub,
-       .flags                  = FTRACE_OPS_FL_RECURSION_SAFE,
+       .flags                  = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
+       INIT_REGEX_LOCK(global_ops)
 };
 
 static int __init ftrace_nodyn_init(void)
@@ -4180,8 +4219,9 @@ ftrace_ops_control_func(unsigned long ip, unsigned long parent_ip,
 }
 
 static struct ftrace_ops control_ops = {
-       .func = ftrace_ops_control_func,
-       .flags = FTRACE_OPS_FL_RECURSION_SAFE,
+       .func   = ftrace_ops_control_func,
+       .flags  = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
+       INIT_REGEX_LOCK(control_ops)
 };
 
 static inline void
@@ -4539,6 +4579,8 @@ int register_ftrace_function(struct ftrace_ops *ops)
 {
        int ret = -1;
 
+       ftrace_ops_init(ops);
+
        mutex_lock(&ftrace_lock);
 
        ret = __register_ftrace_function(ops);