1 files changed, 1105 insertions, 352 deletions

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index fa7ece649fe1..908038f57440 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -39,20 +39,26 @@
 #include "trace_stat.h"
 
 #define FTRACE_WARN_ON(cond)                    \
-        do {                                    \
-                if (WARN_ON(cond))              \
+        ({                                      \
+                int ___r = cond;                \
+                if (WARN_ON(___r))              \
                         ftrace_kill();          \
-        } while (0)
+                ___r;                           \
+        })
 
 #define FTRACE_WARN_ON_ONCE(cond)               \
-        do {                                    \
-                if (WARN_ON_ONCE(cond))         \
+        ({                                      \
+                int ___r = cond;                \
+                if (WARN_ON_ONCE(___r))         \
                         ftrace_kill();          \
-        } while (0)
+                ___r;                           \
+        })
 
 /* hash bits for specific function selection */
 #define FTRACE_HASH_BITS 7
 #define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS)
+#define FTRACE_HASH_DEFAULT_BITS 10
+#define FTRACE_HASH_MAX_BITS 12
 
 /* ftrace_enabled is a method to turn ftrace on or off */
 int ftrace_enabled __read_mostly;
@@ -81,28 +87,40 @@ static struct ftrace_ops ftrace_list_end __read_mostly =
         .func           = ftrace_stub,
 };
 
-static struct ftrace_ops *ftrace_list __read_mostly = &ftrace_list_end;
+static struct ftrace_ops *ftrace_global_list __read_mostly = &ftrace_list_end;
+static struct ftrace_ops *ftrace_ops_list __read_mostly = &ftrace_list_end;
 ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
 ftrace_func_t __ftrace_trace_function __read_mostly = ftrace_stub;
 ftrace_func_t ftrace_pid_function __read_mostly = ftrace_stub;
+static struct ftrace_ops global_ops;
+
+static void
+ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip);
 
 /*
- * Traverse the ftrace_list, invoking all entries.  The reason that we
+ * Traverse the ftrace_global_list, invoking all entries.  The reason that we
  * can use rcu_dereference_raw() 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
- * concurrent insertions into the ftrace_list.
+ * concurrent insertions into the ftrace_global_list.
  *
  * Silly Alpha and silly pointer-speculation compiler optimizations!
  */
-static void ftrace_list_func(unsigned long ip, unsigned long parent_ip)
+static void ftrace_global_list_func(unsigned long ip,
+                                    unsigned long parent_ip)
 {
-        struct ftrace_ops *op = rcu_dereference_raw(ftrace_list); /*see above*/
+        struct ftrace_ops *op;
 
+        if (unlikely(trace_recursion_test(TRACE_GLOBAL_BIT)))
+                return;
+
+        trace_recursion_set(TRACE_GLOBAL_BIT);
+        op = rcu_dereference_raw(ftrace_global_list); /*see above*/
         while (op != &ftrace_list_end) {
                 op->func(ip, parent_ip);
                 op = rcu_dereference_raw(op->next); /*see above*/
         };
+        trace_recursion_clear(TRACE_GLOBAL_BIT);
 }
 
 static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip)
@@ -147,46 +165,69 @@ static void ftrace_test_stop_func(unsigned long ip, unsigned long parent_ip)
 }
 #endif
 
-static int __register_ftrace_function(struct ftrace_ops *ops)
+static void update_global_ops(void)
 {
-        ops->next = ftrace_list;
+        ftrace_func_t func;
+
         /*
-         * We are entering ops into the ftrace_list but another
-         * CPU might be walking that list. We need to make sure
-         * the ops->next pointer is valid before another CPU sees
-         * the ops pointer included into the ftrace_list.
+         * If there's only one function registered, then call that
+         * function directly. Otherwise, we need to iterate over the
+         * registered callers.
          */
-        rcu_assign_pointer(ftrace_list, ops);
+        if (ftrace_global_list == &ftrace_list_end ||
+            ftrace_global_list->next == &ftrace_list_end)
+                func = ftrace_global_list->func;
+        else
+                func = ftrace_global_list_func;
 
-        if (ftrace_enabled) {
-                ftrace_func_t func;
+        /* If we filter on pids, update to use the pid function */
+        if (!list_empty(&ftrace_pids)) {
+                set_ftrace_pid_function(func);
+                func = ftrace_pid_func;
+        }
 
-                if (ops->next == &ftrace_list_end)
-                        func = ops->func;
-                else
-                        func = ftrace_list_func;
+        global_ops.func = func;
+}
 
-                if (!list_empty(&ftrace_pids)) {
-                        set_ftrace_pid_function(func);
-                        func = ftrace_pid_func;
-                }
+static void update_ftrace_function(void)
+{
+        ftrace_func_t func;
+
+        update_global_ops();
+
+        /*
+         * If we are at the end of the list and this ops is
+         * not dynamic, then have the mcount trampoline call
+         * the function directly
+         */
+        if (ftrace_ops_list == &ftrace_list_end ||
+            (ftrace_ops_list->next == &ftrace_list_end &&
+             !(ftrace_ops_list->flags & FTRACE_OPS_FL_DYNAMIC)))
+                func = ftrace_ops_list->func;
+        else
+                func = ftrace_ops_list_func;
 
-                /*
-                 * For one func, simply call it directly.
-                 * For more than one func, call the chain.
-                 */
 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
-                ftrace_trace_function = func;
+        ftrace_trace_function = func;
 #else
-                __ftrace_trace_function = func;
-                ftrace_trace_function = ftrace_test_stop_func;
+        __ftrace_trace_function = func;
+        ftrace_trace_function = ftrace_test_stop_func;
 #endif
-        }
+}
 
-        return 0;
+static void add_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
+{
+        ops->next = *list;
+        /*
+         * We are entering ops into the list but another
+         * CPU might be walking that list. We need to make sure
+         * the ops->next pointer is valid before another CPU sees
+         * the ops pointer included into the list.
+         */
+        rcu_assign_pointer(*list, ops);
 }
 
-static int __unregister_ftrace_function(struct ftrace_ops *ops)
+static int remove_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
 {
         struct ftrace_ops **p;
 
@@ -194,13 +235,12 @@ static int __unregister_ftrace_function(struct ftrace_ops *ops)
          * If we are removing the last function, then simply point
          * to the ftrace_stub.
          */
-        if (ftrace_list == ops && ops->next == &ftrace_list_end) {
-                ftrace_trace_function = ftrace_stub;
-                ftrace_list = &ftrace_list_end;
+        if (*list == ops && ops->next == &ftrace_list_end) {
+                *list = &ftrace_list_end;
                 return 0;
         }
 
-        for (p = &ftrace_list; *p != &ftrace_list_end; p = &(*p)->next)
+        for (p = list; *p != &ftrace_list_end; p = &(*p)->next)
                 if (*p == ops)
                         break;
 
@@ -208,53 +248,83 @@ static int __unregister_ftrace_function(struct ftrace_ops *ops)
                 return -1;
 
         *p = (*p)->next;
+        return 0;
+}
 
-        if (ftrace_enabled) {
-                /* If we only have one func left, then call that directly */
-                if (ftrace_list->next == &ftrace_list_end) {
-                        ftrace_func_t func = ftrace_list->func;
+static int __register_ftrace_function(struct ftrace_ops *ops)
+{
+        if (ftrace_disabled)
+                return -ENODEV;
 
-                        if (!list_empty(&ftrace_pids)) {
-                                set_ftrace_pid_function(func);
-                                func = ftrace_pid_func;
-                        }
-#ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
-                        ftrace_trace_function = func;
-#else
-                        __ftrace_trace_function = func;
-#endif
-                }
-        }
+        if (FTRACE_WARN_ON(ops == &global_ops))
+                return -EINVAL;
+
+        if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED))
+                return -EBUSY;
+
+        if (!core_kernel_data((unsigned long)ops))
+                ops->flags |= FTRACE_OPS_FL_DYNAMIC;
+
+        if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
+                int first = ftrace_global_list == &ftrace_list_end;
+                add_ftrace_ops(&ftrace_global_list, ops);
+                ops->flags |= FTRACE_OPS_FL_ENABLED;
+                if (first)
+                        add_ftrace_ops(&ftrace_ops_list, &global_ops);
+        } else
+                add_ftrace_ops(&ftrace_ops_list, ops);
+
+        if (ftrace_enabled)
+                update_ftrace_function();
 
         return 0;
 }
 
-static void ftrace_update_pid_func(void)
+static int __unregister_ftrace_function(struct ftrace_ops *ops)
 {
-        ftrace_func_t func;
+        int ret;
 
-        if (ftrace_trace_function == ftrace_stub)
-                return;
+        if (ftrace_disabled)
+                return -ENODEV;
 
-#ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
-        func = ftrace_trace_function;
-#else
-        func = __ftrace_trace_function;
-#endif
+        if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
+                return -EBUSY;
 
-        if (!list_empty(&ftrace_pids)) {
-                set_ftrace_pid_function(func);
-                func = ftrace_pid_func;
-        } else {
-                if (func == ftrace_pid_func)
-                        func = ftrace_pid_function;
-        }
+        if (FTRACE_WARN_ON(ops == &global_ops))
+                return -EINVAL;
 
-#ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
-        ftrace_trace_function = func;
-#else
-        __ftrace_trace_function = func;
-#endif
+        if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
+                ret = remove_ftrace_ops(&ftrace_global_list, ops);
+                if (!ret && ftrace_global_list == &ftrace_list_end)
+                        ret = remove_ftrace_ops(&ftrace_ops_list, &global_ops);
+                if (!ret)
+                        ops->flags &= ~FTRACE_OPS_FL_ENABLED;
+        } else
+                ret = remove_ftrace_ops(&ftrace_ops_list, ops);
+
+        if (ret < 0)
+                return ret;
+
+        if (ftrace_enabled)
+                update_ftrace_function();
+
+        /*
+         * Dynamic ops may be freed, we must make sure that all
+         * callers are done before leaving this function.
+         */
+        if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
+                synchronize_sched();
+
+        return 0;
+}
+
+static void ftrace_update_pid_func(void)
+{
+        /* Only do something if we are tracing something */
+        if (ftrace_trace_function == ftrace_stub)
+                return;
+
+        update_ftrace_function();
 }
 
 #ifdef CONFIG_FUNCTION_PROFILER
@@ -800,6 +870,7 @@ static const struct file_operations ftrace_profile_fops = {
         .open           = tracing_open_generic,
         .read           = ftrace_profile_read,
         .write          = ftrace_profile_write,
+        .llseek         = default_llseek,
 };
 
 /* used to initialize the real stat files */
@@ -884,13 +955,38 @@ enum {
         FTRACE_ENABLE_CALLS             = (1 << 0),
         FTRACE_DISABLE_CALLS            = (1 << 1),
         FTRACE_UPDATE_TRACE_FUNC        = (1 << 2),
-        FTRACE_ENABLE_MCOUNT            = (1 << 3),
-        FTRACE_DISABLE_MCOUNT           = (1 << 4),
-        FTRACE_START_FUNC_RET           = (1 << 5),
-        FTRACE_STOP_FUNC_RET            = (1 << 6),
+        FTRACE_START_FUNC_RET           = (1 << 3),
+        FTRACE_STOP_FUNC_RET            = (1 << 4),
+};
+struct ftrace_func_entry {
+        struct hlist_node hlist;
+        unsigned long ip;
+};
+
+struct ftrace_hash {
+        unsigned long           size_bits;
+        struct hlist_head       *buckets;
+        unsigned long           count;
+        struct rcu_head         rcu;
+};
+
+/*
+ * We make these constant because no one should touch them,
+ * but they are used as the default "empty hash", to avoid allocating
+ * it all the time. These are in a read only section such that if
+ * anyone does try to modify it, it will cause an exception.
+ */
+static const struct hlist_head empty_buckets[1];
+static const struct ftrace_hash empty_hash = {
+        .buckets = (struct hlist_head *)empty_buckets,
 };
+#define EMPTY_HASH      ((struct ftrace_hash *)&empty_hash)
 
-static int ftrace_filtered;
+static struct ftrace_ops global_ops = {
+        .func                   = ftrace_stub,
+        .notrace_hash           = EMPTY_HASH,
+        .filter_hash            = EMPTY_HASH,
+};
 
 static struct dyn_ftrace *ftrace_new_addrs;
 
@@ -913,6 +1009,269 @@ static struct ftrace_page	*ftrace_pages;
 
 static struct dyn_ftrace *ftrace_free_records;
 
+static struct ftrace_func_entry *
+ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
+{
+        unsigned long key;
+        struct ftrace_func_entry *entry;
+        struct hlist_head *hhd;
+        struct hlist_node *n;
+
+        if (!hash->count)
+                return NULL;
+
+        if (hash->size_bits > 0)
+                key = hash_long(ip, hash->size_bits);
+        else
+                key = 0;
+
+        hhd = &hash->buckets[key];
+
+        hlist_for_each_entry_rcu(entry, n, hhd, hlist) {
+                if (entry->ip == ip)
+                        return entry;
+        }
+        return NULL;
+}
+
+static void __add_hash_entry(struct ftrace_hash *hash,
+                             struct ftrace_func_entry *entry)
+{
+        struct hlist_head *hhd;
+        unsigned long key;
+
+        if (hash->size_bits)
+                key = hash_long(entry->ip, hash->size_bits);
+        else
+                key = 0;
+
+        hhd = &hash->buckets[key];
+        hlist_add_head(&entry->hlist, hhd);
+        hash->count++;
+}
+
+static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip)
+{
+        struct ftrace_func_entry *entry;
+
+        entry = kmalloc(sizeof(*entry), GFP_KERNEL);
+        if (!entry)
+                return -ENOMEM;
+
+        entry->ip = ip;
+        __add_hash_entry(hash, entry);
+
+        return 0;
+}
+
+static void
+free_hash_entry(struct ftrace_hash *hash,
+                  struct ftrace_func_entry *entry)
+{
+        hlist_del(&entry->hlist);
+        kfree(entry);
+        hash->count--;
+}
+
+static void
+remove_hash_entry(struct ftrace_hash *hash,
+                  struct ftrace_func_entry *entry)
+{
+        hlist_del(&entry->hlist);
+        hash->count--;
+}
+
+static void ftrace_hash_clear(struct ftrace_hash *hash)
+{
+        struct hlist_head *hhd;
+        struct hlist_node *tp, *tn;
+        struct ftrace_func_entry *entry;
+        int size = 1 << hash->size_bits;
+        int i;
+
+        if (!hash->count)
+                return;
+
+        for (i = 0; i < size; i++) {
+                hhd = &hash->buckets[i];
+                hlist_for_each_entry_safe(entry, tp, tn, hhd, hlist)
+                        free_hash_entry(hash, entry);
+        }
+        FTRACE_WARN_ON(hash->count);
+}
+
+static void free_ftrace_hash(struct ftrace_hash *hash)
+{
+        if (!hash || hash == EMPTY_HASH)
+                return;
+        ftrace_hash_clear(hash);
+        kfree(hash->buckets);
+        kfree(hash);
+}
+
+static void __free_ftrace_hash_rcu(struct rcu_head *rcu)
+{
+        struct ftrace_hash *hash;
+
+        hash = container_of(rcu, struct ftrace_hash, rcu);
+        free_ftrace_hash(hash);
+}
+
+static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
+{
+        if (!hash || hash == EMPTY_HASH)
+                return;
+        call_rcu_sched(&hash->rcu, __free_ftrace_hash_rcu);
+}
+
+static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
+{
+        struct ftrace_hash *hash;
+        int size;
+
+        hash = kzalloc(sizeof(*hash), GFP_KERNEL);
+        if (!hash)
+                return NULL;
+
+        size = 1 << size_bits;
+        hash->buckets = kzalloc(sizeof(*hash->buckets) * size, GFP_KERNEL);
+
+        if (!hash->buckets) {
+                kfree(hash);
+                return NULL;
+        }
+
+        hash->size_bits = size_bits;
+
+        return hash;
+}
+
+static struct ftrace_hash *
+alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
+{
+        struct ftrace_func_entry *entry;
+        struct ftrace_hash *new_hash;
+        struct hlist_node *tp;
+        int size;
+        int ret;
+        int i;
+
+        new_hash = alloc_ftrace_hash(size_bits);
+        if (!new_hash)
+                return NULL;
+
+        /* Empty hash? */
+        if (!hash || !hash->count)
+                return new_hash;
+
+        size = 1 << hash->size_bits;
+        for (i = 0; i < size; i++) {
+                hlist_for_each_entry(entry, tp, &hash->buckets[i], hlist) {
+                        ret = add_hash_entry(new_hash, entry->ip);
+                        if (ret < 0)
+                                goto free_hash;
+                }
+        }
+
+        FTRACE_WARN_ON(new_hash->count != hash->count);
+
+        return new_hash;
+
+ free_hash:
+        free_ftrace_hash(new_hash);
+        return NULL;
+}
+
+static int
+ftrace_hash_move(struct ftrace_hash **dst, struct ftrace_hash *src)
+{
+        struct ftrace_func_entry *entry;
+        struct hlist_node *tp, *tn;
+        struct hlist_head *hhd;
+        struct ftrace_hash *old_hash;
+        struct ftrace_hash *new_hash;
+        unsigned long key;
+        int size = src->count;
+        int bits = 0;
+        int i;
+
+        /*
+         * If the new source is empty, just free dst and assign it
+         * the empty_hash.
+         */
+        if (!src->count) {
+                free_ftrace_hash_rcu(*dst);
+                rcu_assign_pointer(*dst, EMPTY_HASH);
+                return 0;
+        }
+
+        /*
+         * Make the hash size about 1/2 the # found
+         */
+        for (size /= 2; size; size >>= 1)
+                bits++;
+
+        /* Don't allocate too much */
+        if (bits > FTRACE_HASH_MAX_BITS)
+                bits = FTRACE_HASH_MAX_BITS;
+
+        new_hash = alloc_ftrace_hash(bits);
+        if (!new_hash)
+                return -ENOMEM;
+
+        size = 1 << src->size_bits;
+        for (i = 0; i < size; i++) {
+                hhd = &src->buckets[i];
+                hlist_for_each_entry_safe(entry, tp, tn, hhd, hlist) {
+                        if (bits > 0)
+                                key = hash_long(entry->ip, bits);
+                        else
+                                key = 0;
+                        remove_hash_entry(src, entry);
+                        __add_hash_entry(new_hash, entry);
+                }
+        }
+
+        old_hash = *dst;
+        rcu_assign_pointer(*dst, new_hash);
+        free_ftrace_hash_rcu(old_hash);
+
+        return 0;
+}
+
+/*
+ * Test the hashes for this ops to see if we want to call
+ * the ops->func or not.
+ *
+ * It's a match if the ip is in the ops->filter_hash or
+ * the filter_hash does not exist or is empty,
+ *  AND
+ * the ip is not in the ops->notrace_hash.
+ *
+ * This needs to be called with preemption disabled as
+ * the hashes are freed with call_rcu_sched().
+ */
+static int
+ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip)
+{
+        struct ftrace_hash *filter_hash;
+        struct ftrace_hash *notrace_hash;
+        int ret;
+
+        filter_hash = rcu_dereference_raw(ops->filter_hash);
+        notrace_hash = rcu_dereference_raw(ops->notrace_hash);
+
+        if ((!filter_hash || !filter_hash->count ||
+             ftrace_lookup_ip(filter_hash, ip)) &&
+            (!notrace_hash || !notrace_hash->count ||
+             !ftrace_lookup_ip(notrace_hash, ip)))
+                ret = 1;
+        else
+                ret = 0;
+
+        return ret;
+}
+
 /*
  * This is a double for. Do not use 'break' to break out of the loop,
  * you must use a goto.
@@ -927,6 +1286,105 @@ static struct dyn_ftrace *ftrace_free_records;
                 }                               \
         }
 
+static void __ftrace_hash_rec_update(struct ftrace_ops *ops,
+                                     int filter_hash,
+                                     bool inc)
+{
+        struct ftrace_hash *hash;
+        struct ftrace_hash *other_hash;
+        struct ftrace_page *pg;
+        struct dyn_ftrace *rec;
+        int count = 0;
+        int all = 0;
+
+        /* Only update if the ops has been registered */
+        if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
+                return;
+
+        /*
+         * In the filter_hash case:
+         *   If the count is zero, we update all records.
+         *   Otherwise we just update the items in the hash.
+         *
+         * In the notrace_hash case:
+         *   We enable the update in the hash.
+         *   As disabling notrace means enabling the tracing,
+         *   and enabling notrace means disabling, the inc variable
+         *   gets inversed.
+         */
+        if (filter_hash) {
+                hash = ops->filter_hash;
+                other_hash = ops->notrace_hash;
+                if (!hash || !hash->count)
+                        all = 1;
+        } else {
+                inc = !inc;
+                hash = ops->notrace_hash;
+                other_hash = ops->filter_hash;
+                /*
+                 * If the notrace hash has no items,
+                 * then there's nothing to do.
+                 */
+                if (hash && !hash->count)
+                        return;
+        }
+
+        do_for_each_ftrace_rec(pg, rec) {
+                int in_other_hash = 0;
+                int in_hash = 0;
+                int match = 0;
+
+                if (all) {
+                        /*
+                         * Only the filter_hash affects all records.
+                         * Update if the record is not in the notrace hash.
+                         */
+                        if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
+                                match = 1;
+                } else {
+                        in_hash = hash && !!ftrace_lookup_ip(hash, rec->ip);
+                        in_other_hash = other_hash && !!ftrace_lookup_ip(other_hash, rec->ip);
+
+                        /*
+                         *
+                         */
+                        if (filter_hash && in_hash && !in_other_hash)
+                                match = 1;
+                        else if (!filter_hash && in_hash &&
+                                 (in_other_hash || !other_hash->count))
+                                match = 1;
+                }
+                if (!match)
+                        continue;
+
+                if (inc) {
+                        rec->flags++;
+                        if (FTRACE_WARN_ON((rec->flags & ~FTRACE_FL_MASK) == FTRACE_REF_MAX))
+                                return;
+                } else {
+                        if (FTRACE_WARN_ON((rec->flags & ~FTRACE_FL_MASK) == 0))
+                                return;
+                        rec->flags--;
+                }
+                count++;
+                /* Shortcut, if we handled all records, we are done. */
+                if (!all && count == hash->count)
+                        return;
+        } while_for_each_ftrace_rec();
+}
+
+static void ftrace_hash_rec_disable(struct ftrace_ops *ops,
+                                    int filter_hash)
+{
+        __ftrace_hash_rec_update(ops, filter_hash, 0);
+}
+
+static void ftrace_hash_rec_enable(struct ftrace_ops *ops,
+                                   int filter_hash)
+{
+        __ftrace_hash_rec_update(ops, filter_hash, 1);
+}
+
 static void ftrace_free_rec(struct dyn_ftrace *rec)
 {
         rec->freelist = ftrace_free_records;
@@ -1048,18 +1506,18 @@ __ftrace_replace_code(struct dyn_ftrace *rec, int enable)
         ftrace_addr = (unsigned long)FTRACE_ADDR;
 
         /*
-         * If this record is not to be traced or we want to disable it,
-         * then disable it.
+         * If we are enabling tracing:
          *
-         * If we want to enable it and filtering is off, then enable it.
+         *   If the record has a ref count, then we need to enable it
+         *   because someone is using it.
          *
-         * If we want to enable it and filtering is on, enable it only if
-         * it's filtered
+         *   Otherwise we make sure its disabled.
+         *
+         * If we are disabling tracing, then disable all records that
+         * are enabled.
          */
-        if (enable && !(rec->flags & FTRACE_FL_NOTRACE)) {
-                if (!ftrace_filtered || (rec->flags & FTRACE_FL_FILTER))
-                        flag = FTRACE_FL_ENABLED;
-        }
+        if (enable && (rec->flags & ~FTRACE_FL_MASK))
+                flag = FTRACE_FL_ENABLED;
 
         /* If the state of this record hasn't changed, then do nothing */
         if ((rec->flags & FTRACE_FL_ENABLED) == flag)
@@ -1080,19 +1538,16 @@ static void ftrace_replace_code(int enable)
         struct ftrace_page *pg;
         int failed;
 
+        if (unlikely(ftrace_disabled))
+                return;
+
         do_for_each_ftrace_rec(pg, rec) {
-                /*
-                 * Skip over free records, records that have
-                 * failed and not converted.
-                 */
-                if (rec->flags & FTRACE_FL_FREE ||
-                    rec->flags & FTRACE_FL_FAILED ||
-                    !(rec->flags & FTRACE_FL_CONVERTED))
+                /* Skip over free records */
+                if (rec->flags & FTRACE_FL_FREE)
                         continue;
 
                 failed = __ftrace_replace_code(rec, enable);
                 if (failed) {
-                        rec->flags |= FTRACE_FL_FAILED;
                         ftrace_bug(failed, rec->ip);
                         /* Stop processing */
                         return;
@@ -1108,10 +1563,12 @@ ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
 
         ip = rec->ip;
 
+        if (unlikely(ftrace_disabled))
+                return 0;
+
         ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
         if (ret) {
                 ftrace_bug(ret, ip);
-                rec->flags |= FTRACE_FL_FAILED;
                 return 0;
         }
         return 1;
@@ -1172,6 +1629,7 @@ static void ftrace_run_update_code(int command)
 
 static ftrace_func_t saved_ftrace_func;
 static int ftrace_start_up;
+static int global_start_up;
 
 static void ftrace_startup_enable(int command)
 {
@@ -1186,19 +1644,38 @@ static void ftrace_startup_enable(int command)
         ftrace_run_update_code(command);
 }
 
-static void ftrace_startup(int command)
+static int ftrace_startup(struct ftrace_ops *ops, int command)
 {
+        bool hash_enable = true;
+
         if (unlikely(ftrace_disabled))
-                return;
+                return -ENODEV;
 
         ftrace_start_up++;
         command |= FTRACE_ENABLE_CALLS;
 
+        /* ops marked global share the filter hashes */
+        if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
+                ops = &global_ops;
+                /* Don't update hash if global is already set */
+                if (global_start_up)
+                        hash_enable = false;
+                global_start_up++;
+        }
+
+        ops->flags |= FTRACE_OPS_FL_ENABLED;
+        if (hash_enable)
+                ftrace_hash_rec_enable(ops, 1);
+
         ftrace_startup_enable(command);
+
+        return 0;
 }
 
-static void ftrace_shutdown(int command)
+static void ftrace_shutdown(struct ftrace_ops *ops, int command)
 {
+        bool hash_disable = true;
+
         if (unlikely(ftrace_disabled))
                 return;
 
@@ -1210,6 +1687,23 @@ static void ftrace_shutdown(int command)
          */
         WARN_ON_ONCE(ftrace_start_up < 0);
 
+        if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
+                ops = &global_ops;
+                global_start_up--;
+                WARN_ON_ONCE(global_start_up < 0);
+                /* Don't update hash if global still has users */
+                if (global_start_up) {
+                        WARN_ON_ONCE(!ftrace_start_up);
+                        hash_disable = false;
+                }
+        }
+
+        if (hash_disable)
+                ftrace_hash_rec_disable(ops, 1);
+
+        if (ops != &global_ops || !global_start_up)
+                ops->flags &= ~FTRACE_OPS_FL_ENABLED;
+
         if (!ftrace_start_up)
                 command |= FTRACE_DISABLE_CALLS;
 
@@ -1226,8 +1720,6 @@ static void ftrace_shutdown(int command)
 
 static void ftrace_startup_sysctl(void)
 {
-        int command = FTRACE_ENABLE_MCOUNT;
-
         if (unlikely(ftrace_disabled))
                 return;
 
@@ -1235,23 +1727,17 @@ static void ftrace_startup_sysctl(void)
         saved_ftrace_func = NULL;
         /* ftrace_start_up is true if we want ftrace running */
         if (ftrace_start_up)
-                command |= FTRACE_ENABLE_CALLS;
-
-        ftrace_run_update_code(command);
+                ftrace_run_update_code(FTRACE_ENABLE_CALLS);
 }
 
 static void ftrace_shutdown_sysctl(void)
 {
-        int command = FTRACE_DISABLE_MCOUNT;
-
         if (unlikely(ftrace_disabled))
                 return;
 
         /* ftrace_start_up is true if ftrace is running */
         if (ftrace_start_up)
-                command |= FTRACE_DISABLE_CALLS;
-
-        ftrace_run_update_code(command);
+                ftrace_run_update_code(FTRACE_DISABLE_CALLS);
 }
 
 static cycle_t          ftrace_update_time;
@@ -1277,15 +1763,15 @@ static int ftrace_update_code(struct module *mod)
                 p->flags = 0L;
 
                 /*
-                 * Do the initial record convertion from mcount jump
+                 * Do the initial record conversion from mcount jump
                  * to the NOP instructions.
                  */
                 if (!ftrace_code_disable(mod, p)) {
                         ftrace_free_rec(p);
-                        continue;
+                        /* Game over */
+                        break;
                 }
 
-                p->flags |= FTRACE_FL_CONVERTED;
                 ftrace_update_cnt++;
 
                 /*
@@ -1360,32 +1846,39 @@ static int __init ftrace_dyn_table_alloc(unsigned long num_to_init)
 enum {
         FTRACE_ITER_FILTER      = (1 << 0),
         FTRACE_ITER_NOTRACE     = (1 << 1),
-        FTRACE_ITER_FAILURES    = (1 << 2),
-        FTRACE_ITER_PRINTALL    = (1 << 3),
-        FTRACE_ITER_HASH        = (1 << 4),
+        FTRACE_ITER_PRINTALL    = (1 << 2),
+        FTRACE_ITER_HASH        = (1 << 3),
+        FTRACE_ITER_ENABLED     = (1 << 4),
 };
 
 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
 
 struct ftrace_iterator {
-        struct ftrace_page      *pg;
-        int                     hidx;
-        int                     idx;
-        unsigned                flags;
-        struct trace_parser     parser;
+        loff_t                          pos;
+        loff_t                          func_pos;
+        struct ftrace_page              *pg;
+        struct dyn_ftrace               *func;
+        struct ftrace_func_probe        *probe;
+        struct trace_parser             parser;
+        struct ftrace_hash              *hash;
+        struct ftrace_ops               *ops;
+        int                             hidx;
+        int                             idx;
+        unsigned                        flags;
 };
 
 static void *
-t_hash_next(struct seq_file *m, void *v, loff_t *pos)
+t_hash_next(struct seq_file *m, loff_t *pos)
 {
         struct ftrace_iterator *iter = m->private;
-        struct hlist_node *hnd = v;
+        struct hlist_node *hnd = NULL;
         struct hlist_head *hhd;
 
-        WARN_ON(!(iter->flags & FTRACE_ITER_HASH));
-
         (*pos)++;
+        iter->pos = *pos;
 
+        if (iter->probe)
+                hnd = &iter->probe->node;
  retry:
         if (iter->hidx >= FTRACE_FUNC_HASHSIZE)
                 return NULL;
@@ -1408,7 +1901,12 @@ t_hash_next(struct seq_file *m, void *v, loff_t *pos)
                 }
         }
 
-        return hnd;
+        if (WARN_ON_ONCE(!hnd))
+                return NULL;
+
+        iter->probe = hlist_entry(hnd, struct ftrace_func_probe, node);
+
+        return iter;
 }
 
 static void *t_hash_start(struct seq_file *m, loff_t *pos)
@@ -1417,26 +1915,32 @@ static void *t_hash_start(struct seq_file *m, loff_t *pos)
         void *p = NULL;
         loff_t l;
 
-        if (!(iter->flags & FTRACE_ITER_HASH))
-                *pos = 0;
-
-        iter->flags |= FTRACE_ITER_HASH;
+        if (iter->func_pos > *pos)
+                return NULL;
 
         iter->hidx = 0;
-        for (l = 0; l <= *pos; ) {
-                p = t_hash_next(m, p, &l);
+        for (l = 0; l <= (*pos - iter->func_pos); ) {
+                p = t_hash_next(m, &l);
                 if (!p)
                         break;
         }
-        return p;
+        if (!p)
+                return NULL;
+
+        /* Only set this if we have an item */
+        iter->flags |= FTRACE_ITER_HASH;
+
+        return iter;
 }
 
-static int t_hash_show(struct seq_file *m, void *v)
+static int
+t_hash_show(struct seq_file *m, struct ftrace_iterator *iter)
 {
         struct ftrace_func_probe *rec;
-        struct hlist_node *hnd = v;
 
-        rec = hlist_entry(hnd, struct ftrace_func_probe, node);
+        rec = iter->probe;
+        if (WARN_ON_ONCE(!rec))
+                return -EIO;
 
         if (rec->ops->print)
                 return rec->ops->print(m, rec->ip, rec->ops, rec->data);
@@ -1454,15 +1958,20 @@ static void *
 t_next(struct seq_file *m, void *v, loff_t *pos)
 {
         struct ftrace_iterator *iter = m->private;
+        struct ftrace_ops *ops = &global_ops;
         struct dyn_ftrace *rec = NULL;
 
+        if (unlikely(ftrace_disabled))
+                return NULL;
+
         if (iter->flags & FTRACE_ITER_HASH)
-                return t_hash_next(m, v, pos);
+                return t_hash_next(m, pos);
 
         (*pos)++;
+        iter->pos = iter->func_pos = *pos;
 
         if (iter->flags & FTRACE_ITER_PRINTALL)
-                return NULL;
+                return t_hash_start(m, pos);
 
  retry:
         if (iter->idx >= iter->pg->index) {
@@ -1475,38 +1984,59 @@ t_next(struct seq_file *m, void *v, loff_t *pos)
                 rec = &iter->pg->records[iter->idx++];
                 if ((rec->flags & FTRACE_FL_FREE) ||
 
-                    (!(iter->flags & FTRACE_ITER_FAILURES) &&
-                     (rec->flags & FTRACE_FL_FAILED)) ||
-
-                    ((iter->flags & FTRACE_ITER_FAILURES) &&
-                     !(rec->flags & FTRACE_FL_FAILED)) ||
-
                     ((iter->flags & FTRACE_ITER_FILTER) &&
-                     !(rec->flags & FTRACE_FL_FILTER)) ||
+                     !(ftrace_lookup_ip(ops->filter_hash, rec->ip))) ||
 
                     ((iter->flags & FTRACE_ITER_NOTRACE) &&
-                     !(rec->flags & FTRACE_FL_NOTRACE))) {
+                     !ftrace_lookup_ip(ops->notrace_hash, rec->ip)) ||
+
+                    ((iter->flags & FTRACE_ITER_ENABLED) &&
+                     !(rec->flags & ~FTRACE_FL_MASK))) {
+
                         rec = NULL;
                         goto retry;
                 }
         }
 
-        return rec;
+        if (!rec)
+                return t_hash_start(m, pos);
+
+        iter->func = rec;
+
+        return iter;
+}
+
+static void reset_iter_read(struct ftrace_iterator *iter)
+{
+        iter->pos = 0;
+        iter->func_pos = 0;
+        iter->flags &= ~(FTRACE_ITER_PRINTALL & FTRACE_ITER_HASH);
 }
 
 static void *t_start(struct seq_file *m, loff_t *pos)
 {
         struct ftrace_iterator *iter = m->private;
+        struct ftrace_ops *ops = &global_ops;
         void *p = NULL;
         loff_t l;
 
         mutex_lock(&ftrace_lock);
+
+        if (unlikely(ftrace_disabled))
+                return NULL;
+
+        /*
+         * If an lseek was done, then reset and start from beginning.
+         */
+        if (*pos < iter->pos)
+                reset_iter_read(iter);
+
         /*
          * For set_ftrace_filter reading, if we have the filter
          * off, we can short cut and just print out that all
          * functions are enabled.
          */
-        if (iter->flags & FTRACE_ITER_FILTER && !ftrace_filtered) {
+        if (iter->flags & FTRACE_ITER_FILTER && !ops->filter_hash->count) {
                 if (*pos > 0)
                         return t_hash_start(m, pos);
                 iter->flags |= FTRACE_ITER_PRINTALL;
@@ -1518,6 +2048,11 @@ static void *t_start(struct seq_file *m, loff_t *pos)
         if (iter->flags & FTRACE_ITER_HASH)
                 return t_hash_start(m, pos);
 
+        /*
+         * Unfortunately, we need to restart at ftrace_pages_start
+         * every time we let go of the ftrace_mutex. This is because
+         * those pointers can change without the lock.
+         */
         iter->pg = ftrace_pages_start;
         iter->idx = 0;
         for (l = 0; l <= *pos; ) {
@@ -1526,10 +2061,14 @@ static void *t_start(struct seq_file *m, loff_t *pos)
                         break;
         }
 
-        if (!p && iter->flags & FTRACE_ITER_FILTER)
-                return t_hash_start(m, pos);
+        if (!p) {
+                if (iter->flags & FTRACE_ITER_FILTER)
+                        return t_hash_start(m, pos);
 
-        return p;
+                return NULL;
+        }
+
+        return iter;
 }
 
 static void t_stop(struct seq_file *m, void *p)
@@ -1540,20 +2079,26 @@ static void t_stop(struct seq_file *m, void *p)
 static int t_show(struct seq_file *m, void *v)
 {
         struct ftrace_iterator *iter = m->private;
-        struct dyn_ftrace *rec = v;
+        struct dyn_ftrace *rec;
 
         if (iter->flags & FTRACE_ITER_HASH)
-                return t_hash_show(m, v);
+                return t_hash_show(m, iter);
 
         if (iter->flags & FTRACE_ITER_PRINTALL) {
                 seq_printf(m, "#### all functions enabled ####\n");
                 return 0;
         }
 
+        rec = iter->func;
+
         if (!rec)
                 return 0;
 
-        seq_printf(m, "%ps\n", (void *)rec->ip);
+        seq_printf(m, "%ps", (void *)rec->ip);
+        if (iter->flags & FTRACE_ITER_ENABLED)
+                seq_printf(m, " (%ld)",
+                           rec->flags & ~FTRACE_FL_MASK);
+        seq_printf(m, "\n");
 
         return 0;
 }
@@ -1593,44 +2138,46 @@ ftrace_avail_open(struct inode *inode, struct file *file)
 }
 
 static int
-ftrace_failures_open(struct inode *inode, struct file *file)
+ftrace_enabled_open(struct inode *inode, struct file *file)
 {
-        int ret;
-        struct seq_file *m;
         struct ftrace_iterator *iter;
+        int ret;
+
+        if (unlikely(ftrace_disabled))
+                return -ENODEV;
+
+        iter = kzalloc(sizeof(*iter), GFP_KERNEL);
+        if (!iter)
+                return -ENOMEM;
+
+        iter->pg = ftrace_pages_start;
+        iter->flags = FTRACE_ITER_ENABLED;
 
-        ret = ftrace_avail_open(inode, file);
+        ret = seq_open(file, &show_ftrace_seq_ops);
         if (!ret) {
-                m = (struct seq_file *)file->private_data;
-                iter = (struct ftrace_iterator *)m->private;
-                iter->flags = FTRACE_ITER_FAILURES;
+                struct seq_file *m = file->private_data;
+
+                m->private = iter;
+        } else {
+                kfree(iter);
         }
 
         return ret;
 }
 
-
-static void ftrace_filter_reset(int enable)
+static void ftrace_filter_reset(struct ftrace_hash *hash)
 {
-        struct ftrace_page *pg;
-        struct dyn_ftrace *rec;
-        unsigned long type = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
-
         mutex_lock(&ftrace_lock);
-        if (enable)
-                ftrace_filtered = 0;
-        do_for_each_ftrace_rec(pg, rec) {
-                if (rec->flags & FTRACE_FL_FAILED)
-                        continue;
-                rec->flags &= ~type;
-        } while_for_each_ftrace_rec();
+        ftrace_hash_clear(hash);
         mutex_unlock(&ftrace_lock);
 }
 
 static int
-ftrace_regex_open(struct inode *inode, struct file *file, int enable)
+ftrace_regex_open(struct ftrace_ops *ops, int flag,
+                  struct inode *inode, struct file *file)
 {
         struct ftrace_iterator *iter;
+        struct ftrace_hash *hash;
         int ret = 0;
 
         if (unlikely(ftrace_disabled))
@@ -1645,21 +2192,42 @@ ftrace_regex_open(struct inode *inode, struct file *file, int enable)
                 return -ENOMEM;
         }
 
+        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;
+                }
+        }
+
         mutex_lock(&ftrace_regex_lock);
+
         if ((file->f_mode & FMODE_WRITE) &&
             (file->f_flags & O_TRUNC))
-                ftrace_filter_reset(enable);
+                ftrace_filter_reset(iter->hash);
 
         if (file->f_mode & FMODE_READ) {
                 iter->pg = ftrace_pages_start;
-                iter->flags = enable ? FTRACE_ITER_FILTER :
-                        FTRACE_ITER_NOTRACE;
 
                 ret = seq_open(file, &show_ftrace_seq_ops);
                 if (!ret) {
                         struct seq_file *m = file->private_data;
                         m->private = iter;
                 } else {
+                        /* Failed */
+                        free_ftrace_hash(iter->hash);
                         trace_parser_put(&iter->parser);
                         kfree(iter);
                 }
@@ -1673,13 +2241,15 @@ ftrace_regex_open(struct inode *inode, struct file *file, int enable)
 static int
 ftrace_filter_open(struct inode *inode, struct file *file)
 {
-        return ftrace_regex_open(inode, file, 1);
+        return ftrace_regex_open(&global_ops, FTRACE_ITER_FILTER,
+                                 inode, file);
 }
 
 static int
 ftrace_notrace_open(struct inode *inode, struct file *file)
 {
-        return ftrace_regex_open(inode, file, 0);
+        return ftrace_regex_open(&global_ops, FTRACE_ITER_NOTRACE,
+                                 inode, file);
 }
 
 static loff_t
@@ -1724,86 +2294,99 @@ static int ftrace_match(char *str, char *regex, int len, int type)
 }
 
 static int
-ftrace_match_record(struct dyn_ftrace *rec, char *regex, int len, int type)
+enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int not)
+{
+        struct ftrace_func_entry *entry;
+        int ret = 0;
+
+        entry = ftrace_lookup_ip(hash, rec->ip);
+        if (not) {
+                /* Do nothing if it doesn't exist */
+                if (!entry)
+                        return 0;
+
+                free_hash_entry(hash, entry);
+        } else {
+                /* Do nothing if it exists */
+                if (entry)
+                        return 0;
+
+                ret = add_hash_entry(hash, rec->ip);
+        }
+        return ret;
+}
+
+static int
+ftrace_match_record(struct dyn_ftrace *rec, char *mod,
+                    char *regex, int len, int type)
 {
         char str[KSYM_SYMBOL_LEN];
+        char *modname;
+
+        kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
+
+        if (mod) {
+                /* module lookup requires matching the module */
+                if (!modname || strcmp(modname, mod))
+                        return 0;
+
+                /* blank search means to match all funcs in the mod */
+                if (!len)
+                        return 1;
+        }
 
-        kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
         return ftrace_match(str, regex, len, type);
 }
 
-static int ftrace_match_records(char *buff, int len, int enable)
+static int
+match_records(struct ftrace_hash *hash, char *buff,
+              int len, char *mod, int not)
 {
-        unsigned int search_len;
+        unsigned search_len = 0;
         struct ftrace_page *pg;
         struct dyn_ftrace *rec;
-        unsigned long flag;
-        char *search;
-        int type;
-        int not;
+        int type = MATCH_FULL;
+        char *search = buff;
         int found = 0;
+        int ret;
 
-        flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
-        type = filter_parse_regex(buff, len, &search, &not);
-
-        search_len = strlen(search);
+        if (len) {
+                type = filter_parse_regex(buff, len, &search, &not);
+                search_len = strlen(search);
+        }
 
         mutex_lock(&ftrace_lock);
-        do_for_each_ftrace_rec(pg, rec) {
 
-                if (rec->flags & FTRACE_FL_FAILED)
-                        continue;
+        if (unlikely(ftrace_disabled))
+                goto out_unlock;
 
-                if (ftrace_match_record(rec, search, search_len, type)) {
-                        if (not)
-                                rec->flags &= ~flag;
-                        else
-                                rec->flags |= flag;
+        do_for_each_ftrace_rec(pg, rec) {
+
+                if (ftrace_match_record(rec, mod, search, search_len, type)) {
+                        ret = enter_record(hash, rec, not);
+                        if (ret < 0) {
+                                found = ret;
+                                goto out_unlock;
+                        }
                         found = 1;
                 }
-                /*
-                 * Only enable filtering if we have a function that
-                 * is filtered on.
-                 */
-                if (enable && (rec->flags & FTRACE_FL_FILTER))
-                        ftrace_filtered = 1;
         } while_for_each_ftrace_rec();
+ out_unlock:
         mutex_unlock(&ftrace_lock);
 
         return found;
 }
 
 static int
-ftrace_match_module_record(struct dyn_ftrace *rec, char *mod,
-                           char *regex, int len, int type)
+ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
 {
-        char str[KSYM_SYMBOL_LEN];
-        char *modname;
-
-        kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
-
-        if (!modname || strcmp(modname, mod))
-                return 0;
-
-        /* blank search means to match all funcs in the mod */
-        if (len)
-                return ftrace_match(str, regex, len, type);
-        else
-                return 1;
+        return match_records(hash, buff, len, NULL, 0);
 }
 
-static int ftrace_match_module_records(char *buff, char *mod, int enable)
+static int
+ftrace_match_module_records(struct ftrace_hash *hash, char *buff, char *mod)
 {
-        unsigned search_len = 0;
-        struct ftrace_page *pg;
-        struct dyn_ftrace *rec;
-        int type = MATCH_FULL;
-        char *search = buff;
-        unsigned long flag;
         int not = 0;
-        int found = 0;
-
-        flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
 
         /* blank or '*' mean the same */
         if (strcmp(buff, "*") == 0)
@@ -1815,32 +2398,7 @@ static int ftrace_match_module_records(char *buff, char *mod, int enable)
                 not = 1;
         }
 
-        if (strlen(buff)) {
-                type = filter_parse_regex(buff, strlen(buff), &search, &not);
-                search_len = strlen(search);
-        }
-
-        mutex_lock(&ftrace_lock);
-        do_for_each_ftrace_rec(pg, rec) {
-
-                if (rec->flags & FTRACE_FL_FAILED)
-                        continue;
-
-                if (ftrace_match_module_record(rec, mod,
-                                               search, search_len, type)) {
-                        if (not)
-                                rec->flags &= ~flag;
-                        else
-                                rec->flags |= flag;
-                        found = 1;
-                }
-                if (enable && (rec->flags & FTRACE_FL_FILTER))
-                        ftrace_filtered = 1;
-
-        } while_for_each_ftrace_rec();
-        mutex_unlock(&ftrace_lock);
-
-        return found;
+        return match_records(hash, buff, strlen(buff), mod, not);
 }
 
 /*
@@ -1851,7 +2409,10 @@ static int ftrace_match_module_records(char *buff, char *mod, int enable)
 static int
 ftrace_mod_callback(char *func, char *cmd, char *param, int enable)
 {
+        struct ftrace_ops *ops = &global_ops;
+        struct ftrace_hash *hash;
         char *mod;
+        int ret = -EINVAL;
 
         /*
          * cmd == 'mod' because we only registered this func
@@ -1863,15 +2424,24 @@ ftrace_mod_callback(char *func, char *cmd, char *param, int enable)
 
         /* we must have a module name */
         if (!param)
-                return -EINVAL;
+                return ret;
 
         mod = strsep(&param, ":");
         if (!strlen(mod))
-                return -EINVAL;
+                return ret;
 
-        if (ftrace_match_module_records(func, mod, enable))
-                return 0;
-        return -EINVAL;
+        if (enable)
+                hash = ops->filter_hash;
+        else
+                hash = ops->notrace_hash;
+
+        ret = ftrace_match_module_records(hash, func, mod);
+        if (!ret)
+                ret = -EINVAL;
+        if (ret < 0)
+                return ret;
+
+        return 0;
 }
 
 static struct ftrace_func_command ftrace_mod_cmd = {
@@ -1922,6 +2492,7 @@ static int ftrace_probe_registered;
 
 static void __enable_ftrace_function_probe(void)
 {
+        int ret;
         int i;
 
         if (ftrace_probe_registered)
@@ -1936,13 +2507,16 @@ static void __enable_ftrace_function_probe(void)
         if (i == FTRACE_FUNC_HASHSIZE)
                 return;
 
-        __register_ftrace_function(&trace_probe_ops);
-        ftrace_startup(0);
+        ret = __register_ftrace_function(&trace_probe_ops);
+        if (!ret)
+                ret = ftrace_startup(&trace_probe_ops, 0);
+
         ftrace_probe_registered = 1;
 }
 
 static void __disable_ftrace_function_probe(void)
 {
+        int ret;
         int i;
 
         if (!ftrace_probe_registered)
@@ -1955,8 +2529,10 @@ static void __disable_ftrace_function_probe(void)
         }
 
         /* no more funcs left */
-        __unregister_ftrace_function(&trace_probe_ops);
-        ftrace_shutdown(0);
+        ret = __unregister_ftrace_function(&trace_probe_ops);
+        if (!ret)
+                ftrace_shutdown(&trace_probe_ops, 0);
+
         ftrace_probe_registered = 0;
 }
 
@@ -1992,12 +2568,13 @@ register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
                 return -EINVAL;
 
         mutex_lock(&ftrace_lock);
-        do_for_each_ftrace_rec(pg, rec) {
 
-                if (rec->flags & FTRACE_FL_FAILED)
-                        continue;
+        if (unlikely(ftrace_disabled))
+                goto out_unlock;
+
+        do_for_each_ftrace_rec(pg, rec) {
 
-                if (!ftrace_match_record(rec, search, len, type))
+                if (!ftrace_match_record(rec, NULL, search, len, type))
                         continue;
 
                 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
@@ -2158,7 +2735,8 @@ int unregister_ftrace_command(struct ftrace_func_command *cmd)
         return ret;
 }
 
-static int ftrace_process_regex(char *buff, int len, int enable)
+static int ftrace_process_regex(struct ftrace_hash *hash,
+                                char *buff, int len, int enable)
 {
         char *func, *command, *next = buff;
         struct ftrace_func_command *p;
@@ -2167,9 +2745,12 @@ static int ftrace_process_regex(char *buff, int len, int enable)
         func = strsep(&next, ":");
 
         if (!next) {
-                if (ftrace_match_records(func, len, enable))
-                        return 0;
-                return ret;
+                ret = ftrace_match_records(hash, func, len);
+                if (!ret)
+                        ret = -EINVAL;
+                if (ret < 0)
+                        return ret;
+                return 0;
         }
 
         /* command found */
@@ -2202,6 +2783,10 @@ ftrace_regex_write(struct file *file, const char __user *ubuf,
 
         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;
@@ -2213,7 +2798,7 @@ ftrace_regex_write(struct file *file, const char __user *ubuf,
 
         if (read >= 0 && trace_parser_loaded(parser) &&
             !trace_parser_cont(parser)) {
-                ret = ftrace_process_regex(parser->buffer,
+                ret = ftrace_process_regex(iter->hash, parser->buffer,
                                            parser->idx, enable);
                 trace_parser_clear(parser);
                 if (ret)
@@ -2241,22 +2826,49 @@ ftrace_notrace_write(struct file *file, const char __user *ubuf,
         return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
 }
 
-static void
-ftrace_set_regex(unsigned char *buf, int len, int reset, int enable)
+static int
+ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
+                 int reset, int enable)
 {
+        struct ftrace_hash **orig_hash;
+        struct ftrace_hash *hash;
+        int ret;
+
+        /* All global ops uses the global ops filters */
+        if (ops->flags & FTRACE_OPS_FL_GLOBAL)
+                ops = &global_ops;
+
         if (unlikely(ftrace_disabled))
-                return;
+                return -ENODEV;
+
+        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;
 
         mutex_lock(&ftrace_regex_lock);
         if (reset)
-                ftrace_filter_reset(enable);
+                ftrace_filter_reset(hash);
         if (buf)
-                ftrace_match_records(buf, len, enable);
+                ftrace_match_records(hash, buf, len);
+
+        mutex_lock(&ftrace_lock);
+        ret = ftrace_hash_move(orig_hash, hash);
+        mutex_unlock(&ftrace_lock);
+
         mutex_unlock(&ftrace_regex_lock);
+
+        free_ftrace_hash(hash);
+        return ret;
 }
 
 /**
  * ftrace_set_filter - set a function to filter on in ftrace
+ * @ops - the ops to set the filter with
  * @buf - the string that holds the function filter text.
  * @len - the length of the string.
  * @reset - non zero to reset all filters before applying this filter.
@@ -2264,13 +2876,16 @@ ftrace_set_regex(unsigned char *buf, int len, int reset, int enable)
  * Filters denote which functions should be enabled when tracing is enabled.
  * If @buf is NULL and reset is set, all functions will be enabled for tracing.
  */
-void ftrace_set_filter(unsigned char *buf, int len, int reset)
+void ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
+                       int len, int reset)
 {
-        ftrace_set_regex(buf, len, reset, 1);
+        ftrace_set_regex(ops, buf, len, reset, 1);
 }
+EXPORT_SYMBOL_GPL(ftrace_set_filter);
 
 /**
  * ftrace_set_notrace - set a function to not trace in ftrace
+ * @ops - the ops to set the notrace filter with
  * @buf - the string that holds the function notrace text.
  * @len - the length of the string.
  * @reset - non zero to reset all filters before applying this filter.
@@ -2279,10 +2894,44 @@ void ftrace_set_filter(unsigned char *buf, int len, int reset)
  * is enabled. If @buf is NULL and reset is set, all functions will be enabled
  * for tracing.
  */
-void ftrace_set_notrace(unsigned char *buf, int len, int reset)
+void ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
+                        int len, int reset)
 {
-        ftrace_set_regex(buf, len, reset, 0);
+        ftrace_set_regex(ops, buf, len, reset, 0);
 }
+EXPORT_SYMBOL_GPL(ftrace_set_notrace);
+/**
+ * ftrace_set_filter - set a function to filter on in ftrace
+ * @ops - the ops to set the filter with
+ * @buf - the string that holds the function filter text.
+ * @len - the length of the string.
+ * @reset - non zero to reset all filters before applying this filter.
+ *
+ * Filters denote which functions should be enabled when tracing is enabled.
+ * If @buf is NULL and reset is set, all functions will be enabled for tracing.
+ */
+void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
+{
+        ftrace_set_regex(&global_ops, buf, len, reset, 1);
+}
+EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
+
+/**
+ * ftrace_set_notrace - set a function to not trace in ftrace
+ * @ops - the ops to set the notrace filter with
+ * @buf - the string that holds the function notrace text.
+ * @len - the length of the string.
+ * @reset - non zero to reset all filters before applying this filter.
+ *
+ * Notrace Filters denote which functions should not be enabled when tracing
+ * is enabled. If @buf is NULL and reset is set, all functions will be enabled
+ * for tracing.
+ */
+void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
+{
+        ftrace_set_regex(&global_ops, buf, len, reset, 0);
+}
+EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
 
 /*
  * command line interface to allow users to set filters on boot up.
@@ -2333,22 +2982,23 @@ static void __init set_ftrace_early_graph(char *buf)
 }
 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 
-static void __init set_ftrace_early_filter(char *buf, int enable)
+static void __init
+set_ftrace_early_filter(struct ftrace_ops *ops, char *buf, int enable)
 {
         char *func;
 
         while (buf) {
                 func = strsep(&buf, ",");
-                ftrace_set_regex(func, strlen(func), 0, enable);
+                ftrace_set_regex(ops, func, strlen(func), 0, enable);
         }
 }
 
 static void __init set_ftrace_early_filters(void)
 {
         if (ftrace_filter_buf[0])
-                set_ftrace_early_filter(ftrace_filter_buf, 1);
+                set_ftrace_early_filter(&global_ops, ftrace_filter_buf, 1);
         if (ftrace_notrace_buf[0])
-                set_ftrace_early_filter(ftrace_notrace_buf, 0);
+                set_ftrace_early_filter(&global_ops, ftrace_notrace_buf, 0);
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
         if (ftrace_graph_buf[0])
                 set_ftrace_early_graph(ftrace_graph_buf);
@@ -2356,11 +3006,14 @@ static void __init set_ftrace_early_filters(void)
 }
 
 static int
-ftrace_regex_release(struct inode *inode, struct file *file, int enable)
+ftrace_regex_release(struct inode *inode, struct file *file)
 {
         struct seq_file *m = (struct seq_file *)file->private_data;
         struct ftrace_iterator *iter;
+        struct ftrace_hash **orig_hash;
         struct trace_parser *parser;
+        int filter_hash;
+        int ret;
 
         mutex_lock(&ftrace_regex_lock);
         if (file->f_mode & FMODE_READ) {
@@ -2373,33 +3026,41 @@ ftrace_regex_release(struct inode *inode, struct file *file, int enable)
         parser = &iter->parser;
         if (trace_parser_loaded(parser)) {
                 parser->buffer[parser->idx] = 0;
-                ftrace_match_records(parser->buffer, parser->idx, enable);
+                ftrace_match_records(iter->hash, parser->buffer, parser->idx);
         }
 
-        mutex_lock(&ftrace_lock);
-        if (ftrace_start_up && ftrace_enabled)
-                ftrace_run_update_code(FTRACE_ENABLE_CALLS);
-        mutex_unlock(&ftrace_lock);
-
         trace_parser_put(parser);
+
+        if (file->f_mode & FMODE_WRITE) {
+                filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
+
+                if (filter_hash)
+                        orig_hash = &iter->ops->filter_hash;
+                else
+                        orig_hash = &iter->ops->notrace_hash;
+
+                mutex_lock(&ftrace_lock);
+                /*
+                 * Remove the current set, update the hash and add
+                 * them back.
+                 */
+                ftrace_hash_rec_disable(iter->ops, filter_hash);
+                ret = ftrace_hash_move(orig_hash, iter->hash);
+                if (!ret) {
+                        ftrace_hash_rec_enable(iter->ops, filter_hash);
+                        if (iter->ops->flags & FTRACE_OPS_FL_ENABLED
+                            && ftrace_enabled)
+                                ftrace_run_update_code(FTRACE_ENABLE_CALLS);
+                }
+                mutex_unlock(&ftrace_lock);
+        }
+        free_ftrace_hash(iter->hash);
         kfree(iter);
 
         mutex_unlock(&ftrace_regex_lock);
         return 0;
 }
 
-static int
-ftrace_filter_release(struct inode *inode, struct file *file)
-{
-        return ftrace_regex_release(inode, file, 1);
-}
-
-static int
-ftrace_notrace_release(struct inode *inode, struct file *file)
-{
-        return ftrace_regex_release(inode, file, 0);
-}
-
 static const struct file_operations ftrace_avail_fops = {
         .open = ftrace_avail_open,
         .read = seq_read,
@@ -2407,8 +3068,8 @@ static const struct file_operations ftrace_avail_fops = {
         .release = seq_release_private,
 };
 
-static const struct file_operations ftrace_failures_fops = {
-        .open = ftrace_failures_open,
+static const struct file_operations ftrace_enabled_fops = {
+        .open = ftrace_enabled_open,
         .read = seq_read,
         .llseek = seq_lseek,
         .release = seq_release_private,
@@ -2418,8 +3079,8 @@ static const struct file_operations ftrace_filter_fops = {
         .open = ftrace_filter_open,
         .read = seq_read,
         .write = ftrace_filter_write,
-        .llseek = no_llseek,
-        .release = ftrace_filter_release,
+        .llseek = ftrace_regex_lseek,
+        .release = ftrace_regex_release,
 };
 
 static const struct file_operations ftrace_notrace_fops = {
@@ -2427,7 +3088,7 @@ static const struct file_operations ftrace_notrace_fops = {
         .read = seq_read,
         .write = ftrace_notrace_write,
         .llseek = ftrace_regex_lseek,
-        .release = ftrace_notrace_release,
+        .release = ftrace_regex_release,
 };
 
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
@@ -2536,9 +3197,6 @@ ftrace_set_func(unsigned long *array, int *idx, char *buffer)
         bool exists;
         int i;
 
-        if (ftrace_disabled)
-                return -ENODEV;
-
         /* decode regex */
         type = filter_parse_regex(buffer, strlen(buffer), &search, &not);
         if (!not && *idx >= FTRACE_GRAPH_MAX_FUNCS)
@@ -2547,12 +3205,18 @@ ftrace_set_func(unsigned long *array, int *idx, char *buffer)
         search_len = strlen(search);
 
         mutex_lock(&ftrace_lock);
+
+        if (unlikely(ftrace_disabled)) {
+                mutex_unlock(&ftrace_lock);
+                return -ENODEV;
+        }
+
         do_for_each_ftrace_rec(pg, rec) {
 
-                if (rec->flags & (FTRACE_FL_FAILED | FTRACE_FL_FREE))
+                if (rec->flags & FTRACE_FL_FREE)
                         continue;
 
-                if (ftrace_match_record(rec, search, search_len, type)) {
+                if (ftrace_match_record(rec, NULL, search, search_len, type)) {
                         /* if it is in the array */
                         exists = false;
                         for (i = 0; i < *idx; i++) {
@@ -2632,6 +3296,7 @@ static const struct file_operations ftrace_graph_fops = {
         .read           = seq_read,
         .write          = ftrace_graph_write,
         .release        = ftrace_graph_release,
+        .llseek         = seq_lseek,
 };
 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 
@@ -2641,8 +3306,8 @@ static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
         trace_create_file("available_filter_functions", 0444,
                         d_tracer, NULL, &ftrace_avail_fops);
 
-        trace_create_file("failures", 0444,
-                        d_tracer, NULL, &ftrace_failures_fops);
+        trace_create_file("enabled_functions", 0444,
+                        d_tracer, NULL, &ftrace_enabled_fops);
 
         trace_create_file("set_ftrace_filter", 0644, d_tracer,
                         NULL, &ftrace_filter_fops);
@@ -2682,7 +3347,10 @@ static int ftrace_process_locs(struct module *mod,
                 ftrace_record_ip(addr);
         }
 
-        /* disable interrupts to prevent kstop machine */
+        /*
+         * Disable interrupts to prevent interrupts from executing
+         * code that is being modified.
+         */
         local_irq_save(flags);
         ftrace_update_code(mod);
         local_irq_restore(flags);
@@ -2697,10 +3365,11 @@ void ftrace_release_mod(struct module *mod)
         struct dyn_ftrace *rec;
         struct ftrace_page *pg;
 
+        mutex_lock(&ftrace_lock);
+
         if (ftrace_disabled)
-                return;
+                goto out_unlock;
 
-        mutex_lock(&ftrace_lock);
         do_for_each_ftrace_rec(pg, rec) {
                 if (within_module_core(rec->ip, mod)) {
                         /*
@@ -2711,6 +3380,7 @@ void ftrace_release_mod(struct module *mod)
                         ftrace_free_rec(rec);
                 }
         } while_for_each_ftrace_rec();
+ out_unlock:
         mutex_unlock(&ftrace_lock);
 }
 
@@ -2797,6 +3467,10 @@ void __init ftrace_init(void)
 
 #else
 
+static struct ftrace_ops global_ops = {
+        .func                   = ftrace_stub,
+};
+
 static int __init ftrace_nodyn_init(void)
 {
         ftrace_enabled = 1;
@@ -2807,12 +3481,47 @@ device_initcall(ftrace_nodyn_init);
 static inline int ftrace_init_dyn_debugfs(struct dentry *d_tracer) { return 0; }
 static inline void ftrace_startup_enable(int command) { }
 /* Keep as macros so we do not need to define the commands */
-# define ftrace_startup(command)        do { } while (0)
-# define ftrace_shutdown(command)       do { } while (0)
+# define ftrace_startup(ops, command)                   \
+        ({                                              \
+                (ops)->flags |= FTRACE_OPS_FL_ENABLED;  \
+                0;                                      \
+        })
+# define ftrace_shutdown(ops, command)  do { } while (0)
 # define ftrace_startup_sysctl()        do { } while (0)
 # define ftrace_shutdown_sysctl()       do { } while (0)
+
+static inline int
+ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip)
+{
+        return 1;
+}
+
 #endif /* CONFIG_DYNAMIC_FTRACE */
 
+static void
+ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip)
+{
+        struct ftrace_ops *op;
+
+        if (unlikely(trace_recursion_test(TRACE_INTERNAL_BIT)))
+                return;
+
+        trace_recursion_set(TRACE_INTERNAL_BIT);
+        /*
+         * Some of the ops may be dynamically allocated,
+         * they must be freed after a synchronize_sched().
+         */
+        preempt_disable_notrace();
+        op = rcu_dereference_raw(ftrace_ops_list);
+        while (op != &ftrace_list_end) {
+                if (ftrace_ops_test(op, ip))
+                        op->func(ip, parent_ip);
+                op = rcu_dereference_raw(op->next);
+        };
+        preempt_enable_notrace();
+        trace_recursion_clear(TRACE_INTERNAL_BIT);
+}
+
 static void clear_ftrace_swapper(void)
 {
         struct task_struct *p;
@@ -3105,19 +3814,23 @@ void ftrace_kill(void)
  */
 int register_ftrace_function(struct ftrace_ops *ops)
 {
-        int ret;
-
-        if (unlikely(ftrace_disabled))
-                return -1;
+        int ret = -1;
 
         mutex_lock(&ftrace_lock);
 
+        if (unlikely(ftrace_disabled))
+                goto out_unlock;
+
         ret = __register_ftrace_function(ops);
-        ftrace_startup(0);
+        if (!ret)
+                ret = ftrace_startup(ops, 0);
 
+
+ out_unlock:
         mutex_unlock(&ftrace_lock);
         return ret;
 }
+EXPORT_SYMBOL_GPL(register_ftrace_function);
 
 /**
  * unregister_ftrace_function - unregister a function for profiling.
@@ -3131,25 +3844,27 @@ int unregister_ftrace_function(struct ftrace_ops *ops)
 
         mutex_lock(&ftrace_lock);
         ret = __unregister_ftrace_function(ops);
-        ftrace_shutdown(0);
+        if (!ret)
+                ftrace_shutdown(ops, 0);
         mutex_unlock(&ftrace_lock);
 
         return ret;
 }
+EXPORT_SYMBOL_GPL(unregister_ftrace_function);
 
 int
 ftrace_enable_sysctl(struct ctl_table *table, int write,
                      void __user *buffer, size_t *lenp,
                      loff_t *ppos)
 {
-        int ret;
-
-        if (unlikely(ftrace_disabled))
-                return -ENODEV;
+        int ret = -ENODEV;
 
         mutex_lock(&ftrace_lock);
 
-        ret  = proc_dointvec(table, write, buffer, lenp, ppos);
+        if (unlikely(ftrace_disabled))
+                goto out;
+
+        ret = proc_dointvec(table, write, buffer, lenp, ppos);
 
         if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
                 goto out;
@@ -3161,11 +3876,11 @@ ftrace_enable_sysctl(struct ctl_table *table, int write,
                 ftrace_startup_sysctl();
 
                 /* we are starting ftrace again */
-                if (ftrace_list != &ftrace_list_end) {
-                        if (ftrace_list->next == &ftrace_list_end)
-                                ftrace_trace_function = ftrace_list->func;
+                if (ftrace_ops_list != &ftrace_list_end) {
+                        if (ftrace_ops_list->next == &ftrace_list_end)
+                                ftrace_trace_function = ftrace_ops_list->func;
                         else
-                                ftrace_trace_function = ftrace_list_func;
+                                ftrace_trace_function = ftrace_ops_list_func;
                 }
 
         } else {
@@ -3289,7 +4004,7 @@ static int start_graph_tracing(void)
         /* The cpu_boot init_task->ret_stack will never be freed */
         for_each_online_cpu(cpu) {
                 if (!idle_task(cpu)->ret_stack)
-                        ftrace_graph_init_task(idle_task(cpu));
+                        ftrace_graph_init_idle_task(idle_task(cpu), cpu);
         }
 
         do {
@@ -3354,7 +4069,7 @@ int register_ftrace_graph(trace_func_graph_ret_t retfunc,
         ftrace_graph_return = retfunc;
         ftrace_graph_entry = entryfunc;
 
-        ftrace_startup(FTRACE_START_FUNC_RET);
+        ret = ftrace_startup(&global_ops, FTRACE_START_FUNC_RET);
 
 out:
         mutex_unlock(&ftrace_lock);
@@ -3371,7 +4086,7 @@ void unregister_ftrace_graph(void)
         ftrace_graph_active--;
         ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
         ftrace_graph_entry = ftrace_graph_entry_stub;
-        ftrace_shutdown(FTRACE_STOP_FUNC_RET);
+        ftrace_shutdown(&global_ops, FTRACE_STOP_FUNC_RET);
         unregister_pm_notifier(&ftrace_suspend_notifier);
         unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
 
@@ -3379,6 +4094,49 @@ void unregister_ftrace_graph(void)
         mutex_unlock(&ftrace_lock);
 }
 
+static DEFINE_PER_CPU(struct ftrace_ret_stack *, idle_ret_stack);
+
+static void
+graph_init_task(struct task_struct *t, struct ftrace_ret_stack *ret_stack)
+{
+        atomic_set(&t->tracing_graph_pause, 0);
+        atomic_set(&t->trace_overrun, 0);
+        t->ftrace_timestamp = 0;
+        /* make curr_ret_stack visible before we add the ret_stack */
+        smp_wmb();
+        t->ret_stack = ret_stack;
+}
+
+/*
+ * Allocate a return stack for the idle task. May be the first
+ * time through, or it may be done by CPU hotplug online.
+ */
+void ftrace_graph_init_idle_task(struct task_struct *t, int cpu)
+{
+        t->curr_ret_stack = -1;
+        /*
+         * The idle task has no parent, it either has its own
+         * stack or no stack at all.
+         */
+        if (t->ret_stack)
+                WARN_ON(t->ret_stack != per_cpu(idle_ret_stack, cpu));
+
+        if (ftrace_graph_active) {
+                struct ftrace_ret_stack *ret_stack;
+
+                ret_stack = per_cpu(idle_ret_stack, cpu);
+                if (!ret_stack) {
+                        ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
+                                            * sizeof(struct ftrace_ret_stack),
+                                            GFP_KERNEL);
+                        if (!ret_stack)
+                                return;
+                        per_cpu(idle_ret_stack, cpu) = ret_stack;
+                }
+                graph_init_task(t, ret_stack);
+        }
+}
+
 /* Allocate a return stack for newly created task */
 void ftrace_graph_init_task(struct task_struct *t)
 {
@@ -3394,12 +4152,7 @@ void ftrace_graph_init_task(struct task_struct *t)
                                 GFP_KERNEL);
                 if (!ret_stack)
                         return;
-                atomic_set(&t->tracing_graph_pause, 0);
-                atomic_set(&t->trace_overrun, 0);
-                t->ftrace_timestamp = 0;
-                /* make curr_ret_stack visable before we add the ret_stack */
-                smp_wmb();
-                t->ret_stack = ret_stack;
+                graph_init_task(t, ret_stack);
         }
 }