There was a lot of clean ups and minor fixes. One of those clean ups was

to the trace_seq code. It also removed the return values to the
 trace_seq_*() functions and use trace_seq_has_overflowed() to see if
 the buffer filled up or not. This is similar to work being done to the
 seq_file code as well in another tree.
 
 Some of the other goodies include:
 
  o Added some "!" (NOT) logic to the tracing filter.
 
  o Fixed the frame pointer logic to the x86_64 mcount trampolines
 
  o Added the logic for dynamic trampolines on !CONFIG_PREEMPT systems.
    That is, the ftrace trampoline can be dynamically allocated
    and be called directly by functions that only have a single hook
    to them.
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Merge tag 'trace-3.19' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing updates from Steven Rostedt:
 "There was a lot of clean ups and minor fixes.  One of those clean ups
  was to the trace_seq code.  It also removed the return values to the
  trace_seq_*() functions and use trace_seq_has_overflowed() to see if
  the buffer filled up or not.  This is similar to work being done to
  the seq_file code as well in another tree.

  Some of the other goodies include:

   - Added some "!" (NOT) logic to the tracing filter.

   - Fixed the frame pointer logic to the x86_64 mcount trampolines

   - Added the logic for dynamic trampolines on !CONFIG_PREEMPT systems.
     That is, the ftrace trampoline can be dynamically allocated and be
     called directly by functions that only have a single hook to them"

* tag 'trace-3.19' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (55 commits)
  tracing: Truncated output is better than nothing
  tracing: Add additional marks to signal very large time deltas
  Documentation: describe trace_buf_size parameter more accurately
  tracing: Allow NOT to filter AND and OR clauses
  tracing: Add NOT to filtering logic
  ftrace/fgraph/x86: Have prepare_ftrace_return() take ip as first parameter
  ftrace/x86: Get rid of ftrace_caller_setup
  ftrace/x86: Have save_mcount_regs macro also save stack frames if needed
  ftrace/x86: Add macro MCOUNT_REG_SIZE for amount of stack used to save mcount regs
  ftrace/x86: Simplify save_mcount_regs on getting RIP
  ftrace/x86: Have save_mcount_regs store RIP in %rdi for first parameter
  ftrace/x86: Rename MCOUNT_SAVE_FRAME and add more detailed comments
  ftrace/x86: Move MCOUNT_SAVE_FRAME out of header file
  ftrace/x86: Have static tracing also use ftrace_caller_setup
  ftrace/x86: Have static function tracing always test for function graph
  kprobes: Add IPMODIFY flag to kprobe_ftrace_ops
  ftrace, kprobes: Support IPMODIFY flag to find IP modify conflict
  kprobes/ftrace: Recover original IP if pre_handler doesn't change it
  tracing/trivial: Fix typos and make an int into a bool
  tracing: Deletion of an unnecessary check before iput()
  ...

include/linux/ftrace.h

@@ -61,6 +61,11 @@ ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops);
 /*
  * FTRACE_OPS_FL_* bits denote the state of ftrace_ops struct and are
  * set in the flags member.
+ * CONTROL, SAVE_REGS, SAVE_REGS_IF_SUPPORTED, RECURSION_SAFE, STUB and
+ * IPMODIFY are a kind of attribute flags which can be set only before
+ * registering the ftrace_ops, and can not be modified while registered.
+ * Changing those attribute flags after regsitering ftrace_ops will
+ * cause unexpected results.
  *
  * ENABLED - set/unset when ftrace_ops is registered/unregistered
  * DYNAMIC - set when ftrace_ops is registered to denote dynamically
@@ -94,6 +99,17 @@ ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops);
  * ADDING  - The ops is in the process of being added.
  * REMOVING - The ops is in the process of being removed.
  * MODIFYING - The ops is in the process of changing its filter functions.
+ * ALLOC_TRAMP - A dynamic trampoline was allocated by the core code.
+ *            The arch specific code sets this flag when it allocated a
+ *            trampoline. This lets the arch know that it can update the
+ *            trampoline in case the callback function changes.
+ *            The ftrace_ops trampoline can be set by the ftrace users, and
+ *            in such cases the arch must not modify it. Only the arch ftrace
+ *            core code should set this flag.
+ * IPMODIFY - The ops can modify the IP register. This can only be set with
+ *            SAVE_REGS. If another ops with this flag set is already registered
+ *            for any of the functions that this ops will be registered for, then
+ *            this ops will fail to register or set_filter_ip.
  */
 enum {
 	FTRACE_OPS_FL_ENABLED			= 1 << 0,
@@ -108,6 +124,8 @@ enum {
 	FTRACE_OPS_FL_ADDING			= 1 << 9,
 	FTRACE_OPS_FL_REMOVING			= 1 << 10,
 	FTRACE_OPS_FL_MODIFYING			= 1 << 11,
+	FTRACE_OPS_FL_ALLOC_TRAMP		= 1 << 12,
+	FTRACE_OPS_FL_IPMODIFY			= 1 << 13,
 };
 
 #ifdef CONFIG_DYNAMIC_FTRACE
@@ -142,6 +160,7 @@ struct ftrace_ops {
 	struct ftrace_ops_hash		*func_hash;
 	struct ftrace_ops_hash		old_hash;
 	unsigned long			trampoline;
+	unsigned long			trampoline_size;
 #endif
 };
 
@@ -255,7 +274,9 @@ struct ftrace_func_command {
 int ftrace_arch_code_modify_prepare(void);
 int ftrace_arch_code_modify_post_process(void);
 
-void ftrace_bug(int err, unsigned long ip);
+struct dyn_ftrace;
+
+void ftrace_bug(int err, struct dyn_ftrace *rec);
 
 struct seq_file;
 
@@ -287,6 +308,8 @@ extern int ftrace_text_reserved(const void *start, const void *end);
 
 extern int ftrace_nr_registered_ops(void);
 
+bool is_ftrace_trampoline(unsigned long addr);
+
 /*
  * The dyn_ftrace record's flags field is split into two parts.
  * the first part which is '0-FTRACE_REF_MAX' is a counter of
@@ -297,6 +320,7 @@ extern int ftrace_nr_registered_ops(void);
  *  ENABLED - the function is being traced
  *  REGS    - the record wants the function to save regs
  *  REGS_EN - the function is set up to save regs.
+ *  IPMODIFY - the record allows for the IP address to be changed.
  *
  * When a new ftrace_ops is registered and wants a function to save
  * pt_regs, the rec->flag REGS is set. When the function has been
@@ -310,10 +334,11 @@ enum {
 	FTRACE_FL_REGS_EN	= (1UL << 29),
 	FTRACE_FL_TRAMP		= (1UL << 28),
 	FTRACE_FL_TRAMP_EN	= (1UL << 27),
+	FTRACE_FL_IPMODIFY	= (1UL << 26),
 };
 
-#define FTRACE_REF_MAX_SHIFT	27
-#define FTRACE_FL_BITS		5
+#define FTRACE_REF_MAX_SHIFT	26
+#define FTRACE_FL_BITS		6
 #define FTRACE_FL_MASKED_BITS	((1UL << FTRACE_FL_BITS) - 1)
 #define FTRACE_FL_MASK		(FTRACE_FL_MASKED_BITS << FTRACE_REF_MAX_SHIFT)
 #define FTRACE_REF_MAX		((1UL << FTRACE_REF_MAX_SHIFT) - 1)
@@ -586,6 +611,11 @@ static inline ssize_t ftrace_notrace_write(struct file *file, const char __user
 			     size_t cnt, loff_t *ppos) { return -ENODEV; }
 static inline int
 ftrace_regex_release(struct inode *inode, struct file *file) { return -ENODEV; }
+
+static inline bool is_ftrace_trampoline(unsigned long addr)
+{
+	return false;
+}
 #endif /* CONFIG_DYNAMIC_FTRACE */
 
 /* totally disable ftrace - can not re-enable after this */

include/linux/ftrace_event.h

@@ -138,6 +138,17 @@ enum print_line_t {
 	TRACE_TYPE_NO_CONSUME	= 3	/* Handled but ask to not consume */
 };
 
+/*
+ * Several functions return TRACE_TYPE_PARTIAL_LINE if the trace_seq
+ * overflowed, and TRACE_TYPE_HANDLED otherwise. This helper function
+ * simplifies those functions and keeps them in sync.
+ */
+static inline enum print_line_t trace_handle_return(struct trace_seq *s)
+{
+	return trace_seq_has_overflowed(s) ?
+		TRACE_TYPE_PARTIAL_LINE : TRACE_TYPE_HANDLED;
+}
+
 void tracing_generic_entry_update(struct trace_entry *entry,
 				  unsigned long flags,
 				  int pc);

include/linux/trace_seq.h

@@ -40,45 +40,54 @@ trace_seq_buffer_ptr(struct trace_seq *s)
 	return s->buffer + s->len;
 }
 
+/**
+ * trace_seq_has_overflowed - return true if the trace_seq took too much
+ * @s: trace sequence descriptor
+ *
+ * Returns true if too much data was added to the trace_seq and it is
+ * now full and will not take anymore.
+ */
+static inline bool trace_seq_has_overflowed(struct trace_seq *s)
+{
+	return s->full || s->len > PAGE_SIZE - 1;
+}
+
 /*
  * Currently only defined when tracing is enabled.
  */
 #ifdef CONFIG_TRACING
 extern __printf(2, 3)
-int trace_seq_printf(struct trace_seq *s, const char *fmt, ...);
+void trace_seq_printf(struct trace_seq *s, const char *fmt, ...);
 extern __printf(2, 0)
-int trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args);
-extern int
+void trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args);
+extern void
 trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary);
 extern int trace_print_seq(struct seq_file *m, struct trace_seq *s);
 extern int trace_seq_to_user(struct trace_seq *s, char __user *ubuf,
 			     int cnt);
-extern int trace_seq_puts(struct trace_seq *s, const char *str);
-extern int trace_seq_putc(struct trace_seq *s, unsigned char c);
-extern int trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len);
-extern int trace_seq_putmem_hex(struct trace_seq *s, const void *mem,
+extern void trace_seq_puts(struct trace_seq *s, const char *str);
+extern void trace_seq_putc(struct trace_seq *s, unsigned char c);
+extern void trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len);
+extern void trace_seq_putmem_hex(struct trace_seq *s, const void *mem,
 				unsigned int len);
 extern int trace_seq_path(struct trace_seq *s, const struct path *path);
 
-extern int trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp,
+extern void trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp,
 			     int nmaskbits);
 
 #else /* CONFIG_TRACING */
-static inline int trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
+static inline void trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
 {
-	return 0;
 }
-static inline int
+static inline void
 trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary)
 {
-	return 0;
 }
 
-static inline int
+static inline void
 trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp,
 		  int nmaskbits)
 {
-	return 0;
 }
 
 static inline int trace_print_seq(struct seq_file *m, struct trace_seq *s)
@@ -90,23 +99,19 @@ static inline int trace_seq_to_user(struct trace_seq *s, char __user *ubuf,
 {
 	return 0;
 }
-static inline int trace_seq_puts(struct trace_seq *s, const char *str)
+static inline void trace_seq_puts(struct trace_seq *s, const char *str)
 {
-	return 0;
 }
-static inline int trace_seq_putc(struct trace_seq *s, unsigned char c)
+static inline void trace_seq_putc(struct trace_seq *s, unsigned char c)
 {
-	return 0;
 }
-static inline int
+static inline void
 trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len)
 {
-	return 0;
 }
-static inline int trace_seq_putmem_hex(struct trace_seq *s, const void *mem,
+static inline void trace_seq_putmem_hex(struct trace_seq *s, const void *mem,
 				       unsigned int len)
 {
-	return 0;
 }
 static inline int trace_seq_path(struct trace_seq *s, const struct path *path)
 {