Merge tag 'trace-v5.1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing updates from Steven Rostedt:
 "The biggest change for this release is in the histogram code:

   - Add "onchange(var)" histogram handler that executes a action when
     $var changes.

   - Add new "snapshot()" action for histogram handlers, that causes a
     snapshot of the ring buffer when triggered. ie.
     onchange(var).snapshot() will trigger a snapshot if var changes.

   - Add alternative for "trace()" action. Currently, to trigger a
     synthetic event, the name of that event is used as the handler
     name, which is inconsistent with the other actions.
     onchange(var).synthetic(param) where it can now be
     onchange(var).trace(synthetic, param). The older method will still
     be allowed, as long as the synthetic events do not overlap with
     other handler names.

   - The histogram documentation at testcases were updated for the new
     changes.

  Outside of the histogram code, we have:

   - Added a quicker way to enable set_ftrace_filter files, that will
     make it much quicker to bisect tracing a function that shouldn't be
     traced and crashes the kernel. (You can echo in numbers to
     set_ftrace_filter, and it will select the corresponding function
     that is in available_filter_functions).

   - Some better displaying of the tracing data (and more information
     was added).

  The rest are small fixes and more clean ups to the code"

* tag 'trace-v5.1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (37 commits)
  tracing: Use strncpy instead of memcpy when copying comm in trace.c
  tracing: Use strncpy instead of memcpy when copying comm for hist triggers
  tracing: Use strncpy instead of memcpy for string keys in hist triggers
  tracing: Use str_has_prefix() in synth_event_create()
  x86/ftrace: Fix warning and considate ftrace_jmp_replace() and ftrace_call_replace()
  tracing/perf: Use strndup_user() instead of buggy open-coded version
  doc: trace: Fix documentation for uprobe_profile
  tracing: Fix spelling mistake: "analagous" -> "analogous"
  tracing: Comment why cond_snapshot is checked outside of max_lock protection
  tracing: Add hist trigger action 'expected fail' test case
  tracing: Add alternative synthetic event trace action test case
  tracing: Add hist trigger onchange() handler test case
  tracing: Add hist trigger snapshot() action test case
  tracing: Add SPDX license GPL-2.0 license identifier to inter-event testcases
  tracing: Add alternative synthetic event trace action syntax
  tracing: Add hist trigger onchange() handler Documentation
  tracing: Add hist trigger onchange() handler
  tracing: Add hist trigger snapshot() action Documentation
  tracing: Add hist trigger snapshot() action
  tracing: Add conditional snapshot
  ...

1 files changed, 17 insertions, 25 deletions

diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index 3e3789c8f8e1..ef49517f6bb2 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -49,7 +49,7 @@ int ftrace_arch_code_modify_post_process(void)
 union ftrace_code_union {
 	char code[MCOUNT_INSN_SIZE];
 	struct {
-		unsigned char e8;
+		unsigned char op;
 		int offset;
 	} __attribute__((packed));
 };
@@ -59,20 +59,23 @@ static int ftrace_calc_offset(long ip, long addr)
 	return (int)(addr - ip);
 }
 
-static unsigned char *ftrace_call_replace(unsigned long ip, unsigned long addr)
+static unsigned char *
+ftrace_text_replace(unsigned char op, unsigned long ip, unsigned long addr)
 {
 	static union ftrace_code_union calc;
 
-	calc.e8		= 0xe8;
+	calc.op		= op;
 	calc.offset	= ftrace_calc_offset(ip + MCOUNT_INSN_SIZE, addr);
 
-	/*
-	 * No locking needed, this must be called via kstop_machine
-	 * which in essence is like running on a uniprocessor machine.
-	 */
 	return calc.code;
 }
 
+static unsigned char *
+ftrace_call_replace(unsigned long ip, unsigned long addr)
+{
+	return ftrace_text_replace(0xe8, ip, addr);
+}
+
 static inline int
 within(unsigned long addr, unsigned long start, unsigned long end)
 {
@@ -665,22 +668,6 @@ int __init ftrace_dyn_arch_init(void)
 	return 0;
 }
 
-#if defined(CONFIG_X86_64) || defined(CONFIG_FUNCTION_GRAPH_TRACER)
-static unsigned char *ftrace_jmp_replace(unsigned long ip, unsigned long addr)
-{
-	static union ftrace_code_union calc;
-
-	/* Jmp not a call (ignore the .e8) */
-	calc.e8		= 0xe9;
-	calc.offset	= ftrace_calc_offset(ip + MCOUNT_INSN_SIZE, addr);
-
-	/*
-	 * ftrace external locks synchronize the access to the static variable.
-	 */
-	return calc.code;
-}
-#endif
-
 /* Currently only x86_64 supports dynamic trampolines */
 #ifdef CONFIG_X86_64
 
@@ -892,8 +879,8 @@ static void *addr_from_call(void *ptr)
 		return NULL;
 
 	/* Make sure this is a call */
-	if (WARN_ON_ONCE(calc.e8 != 0xe8)) {
-		pr_warn("Expected e8, got %x\n", calc.e8);
+	if (WARN_ON_ONCE(calc.op != 0xe8)) {
+		pr_warn("Expected e8, got %x\n", calc.op);
 		return NULL;
 	}
 
@@ -964,6 +951,11 @@ void arch_ftrace_trampoline_free(struct ftrace_ops *ops)
 #ifdef CONFIG_DYNAMIC_FTRACE
 extern void ftrace_graph_call(void);
 
+static unsigned char *ftrace_jmp_replace(unsigned long ip, unsigned long addr)
+{
+	return ftrace_text_replace(0xe9, ip, addr);
+}
+
 static int ftrace_mod_jmp(unsigned long ip, void *func)
 {
 	unsigned char *new;