trace: Don't use __weak in header files

The commit that added a check for this to checkpatch says:

"Using weak declarations can have unintended link defects.  The __weak on
the declaration causes non-weak definitions to become weak."

In this case, when a PowerPC kernel is built with CONFIG_KPROBE_EVENT
but not CONFIG_UPROBE_EVENT, it generates the following warning:

WARNING: 1 bad relocations
c0000000014f2190 R_PPC64_ADDR64    uprobes_fetch_type_table

This is fixed by passing the fetch_table arrays to
traceprobe_parse_probe_arg() which also means that they can never be NULL.

Link: http://lkml.kernel.org/r/20150312165834.4482cb48@canb.auug.org.auAcked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

kernel/trace/trace_kprobe.c

@@ -250,7 +250,7 @@ DEFINE_FETCH_symbol(string_size)
 #define fetch_file_offset_string_size	NULL
 
 /* Fetch type information table */
-const struct fetch_type kprobes_fetch_type_table[] = {
+static const struct fetch_type kprobes_fetch_type_table[] = {
 	/* Special types */
 	[FETCH_TYPE_STRING] = __ASSIGN_FETCH_TYPE("string", string, string,
 					sizeof(u32), 1, "__data_loc char[]"),
@@ -760,7 +760,8 @@ static int create_trace_kprobe(int argc, char **argv)
 
 		/* Parse fetch argument */
 		ret = traceprobe_parse_probe_arg(arg, &tk->tp.size, parg,
-						is_return, true);
+						is_return, true,
+						kprobes_fetch_type_table);
 		if (ret) {
 			pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
 			goto error;

kernel/trace/trace_probe.c

@@ -356,17 +356,14 @@ static int parse_probe_vars(char *arg, const struct fetch_type *t,
 
 /* Recursive argument parser */
 static int parse_probe_arg(char *arg, const struct fetch_type *t,
-		     struct fetch_param *f, bool is_return, bool is_kprobe)
+		     struct fetch_param *f, bool is_return, bool is_kprobe,
+		     const struct fetch_type *ftbl)
 {
-	const struct fetch_type *ftbl;
 	unsigned long param;
 	long offset;
 	char *tmp;
 	int ret = 0;
 
-	ftbl = is_kprobe ? kprobes_fetch_type_table : uprobes_fetch_type_table;
-	BUG_ON(ftbl == NULL);
-
 	switch (arg[0]) {
 	case '$':
 		ret = parse_probe_vars(arg + 1, t, f, is_return, is_kprobe);
@@ -447,7 +444,7 @@ static int parse_probe_arg(char *arg, const struct fetch_type *t,
 			dprm->fetch_size = get_fetch_size_function(t,
 							dprm->fetch, ftbl);
 			ret = parse_probe_arg(arg, t2, &dprm->orig, is_return,
-							is_kprobe);
+							is_kprobe, ftbl);
 			if (ret)
 				kfree(dprm);
 			else {
@@ -505,15 +502,12 @@ static int __parse_bitfield_probe_arg(const char *bf,
 
 /* String length checking wrapper */
 int traceprobe_parse_probe_arg(char *arg, ssize_t *size,
-		struct probe_arg *parg, bool is_return, bool is_kprobe)
+		struct probe_arg *parg, bool is_return, bool is_kprobe,
+		const struct fetch_type *ftbl)
 {
-	const struct fetch_type *ftbl;
 	const char *t;
 	int ret;
 
-	ftbl = is_kprobe ? kprobes_fetch_type_table : uprobes_fetch_type_table;
-	BUG_ON(ftbl == NULL);
-
 	if (strlen(arg) > MAX_ARGSTR_LEN) {
 		pr_info("Argument is too long.: %s\n",  arg);
 		return -ENOSPC;
@@ -535,7 +529,8 @@ int traceprobe_parse_probe_arg(char *arg, ssize_t *size,
 	}
 	parg->offset = *size;
 	*size += parg->type->size;
-	ret = parse_probe_arg(arg, parg->type, &parg->fetch, is_return, is_kprobe);
+	ret = parse_probe_arg(arg, parg->type, &parg->fetch, is_return,
+			      is_kprobe, ftbl);
 
 	if (ret >= 0 && t != NULL)
 		ret = __parse_bitfield_probe_arg(t, parg->type, &parg->fetch);

kernel/trace/trace_probe.h

@@ -229,13 +229,6 @@ ASSIGN_FETCH_FUNC(file_offset, ftype),			\
 #define FETCH_TYPE_STRING	0
 #define FETCH_TYPE_STRSIZE	1
 
-/*
- * Fetch type information table.
- * It's declared as a weak symbol due to conditional compilation.
- */
-extern __weak const struct fetch_type kprobes_fetch_type_table[];
-extern __weak const struct fetch_type uprobes_fetch_type_table[];
-
 #ifdef CONFIG_KPROBE_EVENT
 struct symbol_cache;
 unsigned long update_symbol_cache(struct symbol_cache *sc);
@@ -333,7 +326,8 @@ find_event_file_link(struct trace_probe *tp, struct ftrace_event_file *file)
 }
 
 extern int traceprobe_parse_probe_arg(char *arg, ssize_t *size,
-		   struct probe_arg *parg, bool is_return, bool is_kprobe);
+		   struct probe_arg *parg, bool is_return, bool is_kprobe,
+		   const struct fetch_type *ftbl);
 
 extern int traceprobe_conflict_field_name(const char *name,
 			       struct probe_arg *args, int narg);

kernel/trace/trace_uprobe.c

@@ -196,7 +196,7 @@ DEFINE_FETCH_file_offset(string)
 DEFINE_FETCH_file_offset(string_size)
 
 /* Fetch type information table */
-const struct fetch_type uprobes_fetch_type_table[] = {
+static const struct fetch_type uprobes_fetch_type_table[] = {
 	/* Special types */
 	[FETCH_TYPE_STRING] = __ASSIGN_FETCH_TYPE("string", string, string,
 					sizeof(u32), 1, "__data_loc char[]"),
@@ -535,7 +535,8 @@ static int create_trace_uprobe(int argc, char **argv)
 
 		/* Parse fetch argument */
 		ret = traceprobe_parse_probe_arg(arg, &tu->tp.size, parg,
-						 is_return, false);
+						 is_return, false,
+						 uprobes_fetch_type_table);
 		if (ret) {
 			pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
 			goto error;