ftrace: Rework event_create_dir()

Rework event_create_dir() to use an array of static data instead of
function pointers where possible.

The problem is that it would call the function pointer on module load
before parse_args(), possibly even before jump_labels were initialized.
Luckily the generated functions don't use jump_labels but it still seems
fragile. It also gets in the way of changing when we make the module map
executable.

The generated function are basically calling trace_define_field() with a
bunch of static arguments. So instead of a function, capture these
arguments in a static array, avoiding the function call.

Now there are a number of cases where the fields are dynamic (syscall
arguments, kprobes and uprobes), in which case a static array does not
work, for these we preserve the function call. Luckily all these cases
are not related to modules and so we can retain the function call for
them.

Also fix up all broken tracepoint definitions that now generate a
compile error.

Tested-by: Alexei Starovoitov <ast@kernel.org>
Tested-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20191111132458.342979914@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 14 insertions, 17 deletions

diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index d685c61085c0..298a7cacf146 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -49,6 +49,9 @@ enum trace_type {
 #undef __field
 #define __field(type, item)		type	item;
 
+#undef __field_fn
+#define __field_fn(type, item)		type	item;
+
 #undef __field_struct
 #define __field_struct(type, item)	__field(type, item)
 
@@ -68,26 +71,22 @@ enum trace_type {
 #define F_STRUCT(args...)		args
 
 #undef FTRACE_ENTRY
-#define FTRACE_ENTRY(name, struct_name, id, tstruct, print, filter)	\
+#define FTRACE_ENTRY(name, struct_name, id, tstruct, print)		\
 	struct struct_name {						\
 		struct trace_entry	ent;				\
 		tstruct							\
 	}
 
 #undef FTRACE_ENTRY_DUP
-#define FTRACE_ENTRY_DUP(name, name_struct, id, tstruct, printk, filter)
+#define FTRACE_ENTRY_DUP(name, name_struct, id, tstruct, printk)
 
 #undef FTRACE_ENTRY_REG
-#define FTRACE_ENTRY_REG(name, struct_name, id, tstruct, print,	\
-			 filter, regfn) \
-	FTRACE_ENTRY(name, struct_name, id, PARAMS(tstruct), PARAMS(print), \
-		     filter)
+#define FTRACE_ENTRY_REG(name, struct_name, id, tstruct, print,	regfn)	\
+	FTRACE_ENTRY(name, struct_name, id, PARAMS(tstruct), PARAMS(print))
 
 #undef FTRACE_ENTRY_PACKED
-#define FTRACE_ENTRY_PACKED(name, struct_name, id, tstruct, print,	\
-			    filter)					\
-	FTRACE_ENTRY(name, struct_name, id, PARAMS(tstruct), PARAMS(print), \
-		     filter) __packed
+#define FTRACE_ENTRY_PACKED(name, struct_name, id, tstruct, print)	\
+	FTRACE_ENTRY(name, struct_name, id, PARAMS(tstruct), PARAMS(print)) __packed
 
 #include "trace_entries.h"
 
@@ -1899,17 +1898,15 @@ extern void tracing_log_err(struct trace_array *tr,
 #define internal_trace_puts(str) __trace_puts(_THIS_IP_, str, strlen(str))
 
 #undef FTRACE_ENTRY
-#define FTRACE_ENTRY(call, struct_name, id, tstruct, print, filter)	\
+#define FTRACE_ENTRY(call, struct_name, id, tstruct, print)	\
 	extern struct trace_event_call					\
 	__aligned(4) event_##call;
 #undef FTRACE_ENTRY_DUP
-#define FTRACE_ENTRY_DUP(call, struct_name, id, tstruct, print, filter)	\
-	FTRACE_ENTRY(call, struct_name, id, PARAMS(tstruct), PARAMS(print), \
-		     filter)
+#define FTRACE_ENTRY_DUP(call, struct_name, id, tstruct, print)	\
+	FTRACE_ENTRY(call, struct_name, id, PARAMS(tstruct), PARAMS(print))
 #undef FTRACE_ENTRY_PACKED
-#define FTRACE_ENTRY_PACKED(call, struct_name, id, tstruct, print, filter) \
-	FTRACE_ENTRY(call, struct_name, id, PARAMS(tstruct), PARAMS(print), \
-		     filter)
+#define FTRACE_ENTRY_PACKED(call, struct_name, id, tstruct, print) \
+	FTRACE_ENTRY(call, struct_name, id, PARAMS(tstruct), PARAMS(print))
 
 #include "trace_entries.h"