ftrace: add ftrace_set_filter_ip() for address based filter

Add a new filter update interface ftrace_set_filter_ip()
to set ftrace filter by ip address, not only glob pattern.

Link: http://lkml.kernel.org/r/20120605102808.27845.67952.stgit@localhost.localdomain
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: "Frank Ch. Eigler" <fche@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 9962e954a633c19a11eef7959e53fc4e7543d973..3e711122f66c3c15a15f332e9b65c6e963edb987 100644 (file)
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -317,6 +317,8 @@ struct dyn_ftrace {
 };
 
 int ftrace_force_update(void);
+int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
+                        int remove, int reset);
 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
                       int len, int reset);
 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
@@ -544,6 +546,7 @@ static inline int ftrace_text_reserved(void *start, void *end)
  */
 #define ftrace_regex_open(ops, flag, inod, file) ({ -ENODEV; })
 #define ftrace_set_early_filter(ops, buf, enable) do { } while (0)
+#define ftrace_set_filter_ip(ops, ip, remove, reset) ({ -ENODEV; })
 #define ftrace_set_filter(ops, buf, len, reset) ({ -ENODEV; })
 #define ftrace_set_notrace(ops, buf, len, reset) ({ -ENODEV; })
 #define ftrace_free_filter(ops) do { } while (0)

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 528d997c7f99ab7b6bab6ba0f11527eb673418d7..9dcf15d38380356a2288ec97b098c002d9bca01d 100644 (file)
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -3242,8 +3242,27 @@ ftrace_notrace_write(struct file *file, const char __user *ubuf,
 }
 
 static int
-ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
-                int reset, int enable)
+ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove)
+{
+       struct ftrace_func_entry *entry;
+
+       if (!ftrace_location(ip))
+               return -EINVAL;
+
+       if (remove) {
+               entry = ftrace_lookup_ip(hash, ip);
+               if (!entry)
+                       return -ENOENT;
+               free_hash_entry(hash, entry);
+               return 0;
+       }
+
+       return add_hash_entry(hash, ip);
+}
+
+static int
+ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
+               unsigned long ip, int remove, int reset, int enable)
 {
        struct ftrace_hash **orig_hash;
        struct ftrace_hash *hash;
@@ -3272,6 +3291,11 @@ ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
                ret = -EINVAL;
                goto out_regex_unlock;
        }
+       if (ip) {
+               ret = ftrace_match_addr(hash, ip, remove);
+               if (ret < 0)
+                       goto out_regex_unlock;
+       }
 
        mutex_lock(&ftrace_lock);
        ret = ftrace_hash_move(ops, enable, orig_hash, hash);
@@ -3288,6 +3312,37 @@ ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
        return ret;
 }
 
+static int
+ftrace_set_addr(struct ftrace_ops *ops, unsigned long ip, int remove,
+               int reset, int enable)
+{
+       return ftrace_set_hash(ops, 0, 0, ip, remove, reset, enable);
+}
+
+/**
+ * ftrace_set_filter_ip - set a function to filter on in ftrace by address
+ * @ops - the ops to set the filter with
+ * @ip - the address to add to or remove from the filter.
+ * @remove - non zero to remove the ip from the filter
+ * @reset - non zero to reset all filters before applying this filter.
+ *
+ * Filters denote which functions should be enabled when tracing is enabled
+ * If @ip is NULL, it failes to update filter.
+ */
+int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
+                        int remove, int reset)
+{
+       return ftrace_set_addr(ops, ip, remove, reset, 1);
+}
+EXPORT_SYMBOL_GPL(ftrace_set_filter_ip);
+
+static int
+ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
+                int reset, int enable)
+{
+       return ftrace_set_hash(ops, buf, len, 0, 0, reset, enable);
+}
+
 /**
  * ftrace_set_filter - set a function to filter on in ftrace
  * @ops - the ops to set the filter with