2 files changed, 513 insertions, 18 deletions

diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index b0dd0093058f..f5911d2d42c3 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -43,7 +43,9 @@ extern void mcount(void);
 # define FTRACE_HASHSIZE        (1<<FTRACE_HASHBITS)
 
 enum {
-        FTRACE_FL_FAILED        = (1<<0),
+        FTRACE_FL_FAILED        = (1 << 0),
+        FTRACE_FL_FILTER        = (1 << 1),
+        FTRACE_FL_ENABLED       = (1 << 2),
 };
 
 struct dyn_ftrace {
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 88544f9bc0ed..97d5cb7b7e75 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -16,12 +16,15 @@
 #include <linux/stop_machine.h>
 #include <linux/clocksource.h>
 #include <linux/kallsyms.h>
+#include <linux/seq_file.h>
+#include <linux/debugfs.h>
 #include <linux/kthread.h>
 #include <linux/hardirq.h>
 #include <linux/ftrace.h>
-#include <linux/module.h>
+#include <linux/uaccess.h>
 #include <linux/sysctl.h>
 #include <linux/hash.h>
+#include <linux/ctype.h>
 #include <linux/list.h>
 
 #include "trace.h"
@@ -151,12 +154,15 @@ enum {
         FTRACE_DISABLE_MCOUNT           = (1 << 4),
 };
 
+static int ftrace_filtered;
+
 static struct hlist_head ftrace_hash[FTRACE_HASHSIZE];
 
 static DEFINE_PER_CPU(int, ftrace_shutdown_disable_cpu);
 
 static DEFINE_SPINLOCK(ftrace_shutdown_lock);
 static DEFINE_MUTEX(ftraced_lock);
+static DEFINE_MUTEX(ftrace_filter_lock);
 
 struct ftrace_page {
         struct ftrace_page      *next;
@@ -282,16 +288,82 @@ ftrace_record_ip(unsigned long ip)
 #define FTRACE_ADDR ((long)(&ftrace_caller))
 #define MCOUNT_ADDR ((long)(&mcount))
 
-static void notrace ftrace_replace_code(int saved)
+static void notrace
+__ftrace_replace_code(struct dyn_ftrace *rec,
+                      unsigned char *old, unsigned char *new, int enable)
+{
+        unsigned long ip;
+        int failed;
+
+        ip = rec->ip;
+
+        if (ftrace_filtered && enable) {
+                unsigned long fl;
+                /*
+                 * If filtering is on:
+                 *
+                 * If this record is set to be filtered and
+                 * is enabled then do nothing.
+                 *
+                 * If this record is set to be filtered and
+                 * it is not enabled, enable it.
+                 *
+                 * If this record is not set to be filtered
+                 * and it is not enabled do nothing.
+                 *
+                 * If this record is not set to be filtered and
+                 * it is enabled, disable it.
+                 */
+                fl = rec->flags & (FTRACE_FL_FILTER | FTRACE_FL_ENABLED);
+
+                if ((fl ==  (FTRACE_FL_FILTER | FTRACE_FL_ENABLED)) ||
+                    (fl == 0))
+                        return;
+
+                /*
+                 * If it is enabled disable it,
+                 * otherwise enable it!
+                 */
+                if (fl == FTRACE_FL_ENABLED) {
+                        /* swap new and old */
+                        new = old;
+                        old = ftrace_call_replace(ip, FTRACE_ADDR);
+                        rec->flags &= ~FTRACE_FL_ENABLED;
+                } else {
+                        new = ftrace_call_replace(ip, FTRACE_ADDR);
+                        rec->flags |= FTRACE_FL_ENABLED;
+                }
+        } else {
+
+                if (enable)
+                        new = ftrace_call_replace(ip, FTRACE_ADDR);
+                else
+                        old = ftrace_call_replace(ip, FTRACE_ADDR);
+
+                if (enable) {
+                        if (rec->flags & FTRACE_FL_ENABLED)
+                                return;
+                        rec->flags |= FTRACE_FL_ENABLED;
+                } else {
+                        if (!(rec->flags & FTRACE_FL_ENABLED))
+                                return;
+                        rec->flags &= ~FTRACE_FL_ENABLED;
+                }
+        }
+
+        failed = ftrace_modify_code(ip, old, new);
+        if (failed)
+                rec->flags |= FTRACE_FL_FAILED;
+}
+
+static void notrace ftrace_replace_code(int enable)
 {
         unsigned char *new = NULL, *old = NULL;
         struct dyn_ftrace *rec;
         struct ftrace_page *pg;
-        unsigned long ip;
-        int failed;
         int i;
 
-        if (saved)
+        if (enable)
                 old = ftrace_nop_replace();
         else
                 new = ftrace_nop_replace();
@@ -304,16 +376,7 @@ static void notrace ftrace_replace_code(int saved)
                         if (rec->flags & FTRACE_FL_FAILED)
                                 continue;
 
-                        ip = rec->ip;
-
-                        if (saved)
-                                new = ftrace_call_replace(ip, FTRACE_ADDR);
-                        else
-                                old = ftrace_call_replace(ip, FTRACE_ADDR);
-
-                        failed = ftrace_modify_code(ip, old, new);
-                        if (failed)
-                                rec->flags |= FTRACE_FL_FAILED;
+                        __ftrace_replace_code(rec, old, new, enable);
                 }
         }
 }
@@ -580,6 +643,436 @@ static int __init ftrace_dyn_table_alloc(void)
         return 0;
 }
 
+enum {
+        FTRACE_ITER_FILTER      = (1 << 0),
+        FTRACE_ITER_CONT        = (1 << 1),
+};
+
+#define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
+
+struct ftrace_iterator {
+        loff_t                  pos;
+        struct ftrace_page      *pg;
+        unsigned                idx;
+        unsigned                flags;
+        unsigned char           buffer[FTRACE_BUFF_MAX+1];
+        unsigned                buffer_idx;
+        unsigned                filtered;
+};
+
+static void notrace *
+t_next(struct seq_file *m, void *v, loff_t *pos)
+{
+        struct ftrace_iterator *iter = m->private;
+        struct dyn_ftrace *rec = NULL;
+
+        (*pos)++;
+
+ retry:
+        if (iter->idx >= iter->pg->index) {
+                if (iter->pg->next) {
+                        iter->pg = iter->pg->next;
+                        iter->idx = 0;
+                        goto retry;
+                }
+        } else {
+                rec = &iter->pg->records[iter->idx++];
+                if ((rec->flags & FTRACE_FL_FAILED) ||
+                    ((iter->flags & FTRACE_ITER_FILTER) &&
+                     !(rec->flags & FTRACE_FL_FILTER))) {
+                        rec = NULL;
+                        goto retry;
+                }
+        }
+
+        iter->pos = *pos;
+
+        return rec;
+}
+
+static void *t_start(struct seq_file *m, loff_t *pos)
+{
+        struct ftrace_iterator *iter = m->private;
+        void *p = NULL;
+        loff_t l = -1;
+
+        if (*pos != iter->pos) {
+                for (p = t_next(m, p, &l); p && l < *pos; p = t_next(m, p, &l))
+                        ;
+        } else {
+                l = *pos;
+                p = t_next(m, p, &l);
+        }
+
+        return p;
+}
+
+static void t_stop(struct seq_file *m, void *p)
+{
+}
+
+static int t_show(struct seq_file *m, void *v)
+{
+        struct dyn_ftrace *rec = v;
+        char str[KSYM_SYMBOL_LEN];
+
+        if (!rec)
+                return 0;
+
+        kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
+
+        seq_printf(m, "%s\n", str);
+
+        return 0;
+}
+
+static struct seq_operations show_ftrace_seq_ops = {
+        .start = t_start,
+        .next = t_next,
+        .stop = t_stop,
+        .show = t_show,
+};
+
+static int notrace
+ftrace_avail_open(struct inode *inode, struct file *file)
+{
+        struct ftrace_iterator *iter;
+        int ret;
+
+        iter = kzalloc(sizeof(*iter), GFP_KERNEL);
+        if (!iter)
+                return -ENOMEM;
+
+        iter->pg = ftrace_pages_start;
+        iter->pos = -1;
+
+        ret = seq_open(file, &show_ftrace_seq_ops);
+        if (!ret) {
+                struct seq_file *m = file->private_data;
+                m->private = iter;
+        } else
+                kfree(iter);
+
+        return ret;
+}
+
+int ftrace_avail_release(struct inode *inode, struct file *file)
+{
+        struct seq_file *m = (struct seq_file *)file->private_data;
+        struct ftrace_iterator *iter = m->private;
+
+        seq_release(inode, file);
+        kfree(iter);
+        return 0;
+}
+
+static void notrace ftrace_filter_reset(void)
+{
+        struct ftrace_page *pg;
+        struct dyn_ftrace *rec;
+        unsigned i;
+
+        /* keep kstop machine from running */
+        preempt_disable();
+        ftrace_filtered = 0;
+        pg = ftrace_pages_start;
+        while (pg) {
+                for (i = 0; i < pg->index; i++) {
+                        rec = &pg->records[i];
+                        if (rec->flags & FTRACE_FL_FAILED)
+                                continue;
+                        rec->flags &= ~FTRACE_FL_FILTER;
+                }
+                pg = pg->next;
+        }
+        preempt_enable();
+}
+
+static int notrace
+ftrace_filter_open(struct inode *inode, struct file *file)
+{
+        struct ftrace_iterator *iter;
+        int ret = 0;
+
+        iter = kzalloc(sizeof(*iter), GFP_KERNEL);
+        if (!iter)
+                return -ENOMEM;
+
+        mutex_lock(&ftrace_filter_lock);
+        if ((file->f_mode & FMODE_WRITE) &&
+            !(file->f_flags & O_APPEND))
+                ftrace_filter_reset();
+
+        if (file->f_mode & FMODE_READ) {
+                iter->pg = ftrace_pages_start;
+                iter->pos = -1;
+                iter->flags = FTRACE_ITER_FILTER;
+
+                ret = seq_open(file, &show_ftrace_seq_ops);
+                if (!ret) {
+                        struct seq_file *m = file->private_data;
+                        m->private = iter;
+                } else
+                        kfree(iter);
+        } else
+                file->private_data = iter;
+        mutex_unlock(&ftrace_filter_lock);
+
+        return ret;
+}
+
+static ssize_t notrace
+ftrace_filter_read(struct file *file, char __user *ubuf,
+                       size_t cnt, loff_t *ppos)
+{
+        if (file->f_mode & FMODE_READ)
+                return seq_read(file, ubuf, cnt, ppos);
+        else
+                return -EPERM;
+}
+
+static loff_t notrace
+ftrace_filter_lseek(struct file *file, loff_t offset, int origin)
+{
+        loff_t ret;
+
+        if (file->f_mode & FMODE_READ)
+                ret = seq_lseek(file, offset, origin);
+        else
+                file->f_pos = ret = 1;
+
+        return ret;
+}
+
+enum {
+        MATCH_FULL,
+        MATCH_FRONT_ONLY,
+        MATCH_MIDDLE_ONLY,
+        MATCH_END_ONLY,
+};
+
+static void notrace
+ftrace_match(unsigned char *buff, int len)
+{
+        char str[KSYM_SYMBOL_LEN];
+        char *search = NULL;
+        struct ftrace_page *pg;
+        struct dyn_ftrace *rec;
+        int type = MATCH_FULL;
+        unsigned i, match = 0, search_len = 0;
+
+        for (i = 0; i < len; i++) {
+                if (buff[i] == '*') {
+                        if (!i) {
+                                search = buff + i + 1;
+                                type = MATCH_END_ONLY;
+                                search_len = len - (i + 1);
+                        } else {
+                                if (type == MATCH_END_ONLY) {
+                                        type = MATCH_MIDDLE_ONLY;
+                                } else {
+                                        match = i;
+                                        type = MATCH_FRONT_ONLY;
+                                }
+                                buff[i] = 0;
+                                break;
+                        }
+                }
+        }
+
+        /* keep kstop machine from running */
+        preempt_disable();
+        ftrace_filtered = 1;
+        pg = ftrace_pages_start;
+        while (pg) {
+                for (i = 0; i < pg->index; i++) {
+                        int matched = 0;
+                        char *ptr;
+
+                        rec = &pg->records[i];
+                        if (rec->flags & FTRACE_FL_FAILED)
+                                continue;
+                        kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
+                        switch (type) {
+                        case MATCH_FULL:
+                                if (strcmp(str, buff) == 0)
+                                        matched = 1;
+                                break;
+                        case MATCH_FRONT_ONLY:
+                                if (memcmp(str, buff, match) == 0)
+                                        matched = 1;
+                                break;
+                        case MATCH_MIDDLE_ONLY:
+                                if (strstr(str, search))
+                                        matched = 1;
+                                break;
+                        case MATCH_END_ONLY:
+                                ptr = strstr(str, search);
+                                if (ptr && (ptr[search_len] == 0))
+                                        matched = 1;
+                                break;
+                        }
+                        if (matched)
+                                rec->flags |= FTRACE_FL_FILTER;
+                }
+                pg = pg->next;
+        }
+        preempt_enable();
+}
+
+static ssize_t notrace
+ftrace_filter_write(struct file *file, const char __user *ubuf,
+                    size_t cnt, loff_t *ppos)
+{
+        struct ftrace_iterator *iter;
+        char ch;
+        size_t read = 0;
+        ssize_t ret;
+
+        if (!cnt || cnt < 0)
+                return 0;
+
+        mutex_lock(&ftrace_filter_lock);
+
+        if (file->f_mode & FMODE_READ) {
+                struct seq_file *m = file->private_data;
+                iter = m->private;
+        } else
+                iter = file->private_data;
+
+        if (!*ppos) {
+                iter->flags &= ~FTRACE_ITER_CONT;
+                iter->buffer_idx = 0;
+        }
+
+        ret = get_user(ch, ubuf++);
+        if (ret)
+                goto out;
+        read++;
+        cnt--;
+
+        if (!(iter->flags & ~FTRACE_ITER_CONT)) {
+                /* skip white space */
+                while (cnt && isspace(ch)) {
+                        ret = get_user(ch, ubuf++);
+                        if (ret)
+                                goto out;
+                        read++;
+                        cnt--;
+                }
+
+
+                if (isspace(ch)) {
+                        file->f_pos += read;
+                        ret = read;
+                        goto out;
+                }
+
+                iter->buffer_idx = 0;
+        }
+
+        while (cnt && !isspace(ch)) {
+                if (iter->buffer_idx < FTRACE_BUFF_MAX)
+                        iter->buffer[iter->buffer_idx++] = ch;
+                else {
+                        ret = -EINVAL;
+                        goto out;
+                }
+                ret = get_user(ch, ubuf++);
+                if (ret)
+                        goto out;
+                read++;
+                cnt--;
+        }
+
+        if (isspace(ch)) {
+                iter->filtered++;
+                iter->buffer[iter->buffer_idx] = 0;
+                ftrace_match(iter->buffer, iter->buffer_idx);
+                iter->buffer_idx = 0;
+        } else
+                iter->flags |= FTRACE_ITER_CONT;
+
+
+        file->f_pos += read;
+
+        ret = read;
+ out:
+        mutex_unlock(&ftrace_filter_lock);
+
+        return ret;
+}
+
+static int notrace
+ftrace_filter_release(struct inode *inode, struct file *file)
+{
+        struct seq_file *m = (struct seq_file *)file->private_data;
+        struct ftrace_iterator *iter;
+
+        mutex_lock(&ftrace_filter_lock);
+        if (file->f_mode & FMODE_READ) {
+                iter = m->private;
+
+                seq_release(inode, file);
+        } else
+                iter = file->private_data;
+
+        if (iter->buffer_idx) {
+                iter->filtered++;
+                iter->buffer[iter->buffer_idx] = 0;
+                ftrace_match(iter->buffer, iter->buffer_idx);
+        }
+
+        mutex_lock(&ftrace_sysctl_lock);
+        mutex_lock(&ftraced_lock);
+        if (iter->filtered && ftraced_suspend && ftrace_enabled)
+                ftrace_run_update_code(FTRACE_ENABLE_CALLS);
+        mutex_unlock(&ftraced_lock);
+        mutex_unlock(&ftrace_sysctl_lock);
+
+        kfree(iter);
+        mutex_unlock(&ftrace_filter_lock);
+        return 0;
+}
+
+static struct file_operations ftrace_avail_fops = {
+        .open = ftrace_avail_open,
+        .read = seq_read,
+        .llseek = seq_lseek,
+        .release = ftrace_avail_release,
+};
+
+static struct file_operations ftrace_filter_fops = {
+        .open = ftrace_filter_open,
+        .read = ftrace_filter_read,
+        .write = ftrace_filter_write,
+        .llseek = ftrace_filter_lseek,
+        .release = ftrace_filter_release,
+};
+
+static __init int ftrace_init_debugfs(void)
+{
+        struct dentry *d_tracer;
+        struct dentry *entry;
+
+        d_tracer = tracing_init_dentry();
+
+        entry = debugfs_create_file("available_filter_functions", 0444,
+                                    d_tracer, NULL, &ftrace_avail_fops);
+        if (!entry)
+                pr_warning("Could not create debugfs "
+                           "'available_filter_functions' entry\n");
+
+        entry = debugfs_create_file("set_ftrace_filter", 0644, d_tracer,
+                                    NULL, &ftrace_filter_fops);
+        if (!entry)
+                pr_warning("Could not create debugfs "
+                           "'set_ftrace_filter' entry\n");
+        return 0;
+}
+
+fs_initcall(ftrace_init_debugfs);
+
 static int __init notrace ftrace_dynamic_init(void)
 {
         struct task_struct *p;
@@ -657,14 +1150,14 @@ int unregister_ftrace_function(struct ftrace_ops *ops)
 
 notrace int
 ftrace_enable_sysctl(struct ctl_table *table, int write,
-                     struct file *filp, void __user *buffer, size_t *lenp,
+                     struct file *file, void __user *buffer, size_t *lenp,
                      loff_t *ppos)
 {
         int ret;
 
         mutex_lock(&ftrace_sysctl_lock);
 
-        ret  = proc_dointvec(table, write, filp, buffer, lenp, ppos);
+        ret  = proc_dointvec(table, write, file, buffer, lenp, ppos);
 
         if (ret || !write || (last_ftrace_enabled == ftrace_enabled))
                 goto out;