modpost: track if the symbol origin is a dump file or ELF object

The meaning of sym->kernel is obscure; it is set for in-kernel symbols
loaded from Modules.symvers. This happens only when we are building
external modules, and it is used to determine whether to dump symbols
to $(KBUILD_EXTMOD)/Modules.symvers

It is clearer to remember whether the symbol or module came from a dump
file or ELF object.

This changes the KBUILD_EXTRA_SYMBOLS behavior. Previously, symbols
loaded from KBUILD_EXTRA_SYMBOLS are accumulated into the current
$(KBUILD_EXTMOD)/Modules.symvers

Going forward, they will be only used to check symbol references, but
not dumped into the current $(KBUILD_EXTMOD)/Modules.symvers. I believe
this makes more sense.

sym->vmlinux will have no user. Remove it too.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

scripts/mod/modpost.c

@@ -161,9 +161,6 @@ struct symbol {
 	int crc_valid;
 	char *namespace;
 	unsigned int weak:1;
-	unsigned int vmlinux:1;    /* 1 if symbol is defined in vmlinux */
-	unsigned int kernel:1;     /* 1 if symbol is from kernel
-				    *  (only for external modules) **/
 	unsigned int is_static:1;  /* 1 if symbol is not global */
 	enum export  export;       /* Type of export */
 	char name[];
@@ -398,8 +395,6 @@ static struct symbol *sym_add_exported(const char *name, struct module *mod,
 	}
 
 	s->module = mod;
-	s->vmlinux   = is_vmlinux(mod->name);
-	s->kernel    = 0;
 	s->export    = export;
 	return s;
 }
@@ -2427,7 +2422,7 @@ static void write_if_changed(struct buffer *b, const char *fname)
 /* parse Module.symvers file. line format:
  * 0x12345678<tab>symbol<tab>module<tab>export<tab>namespace
  **/
-static void read_dump(const char *fname, unsigned int kernel)
+static void read_dump(const char *fname)
 {
 	unsigned long size, pos = 0;
 	void *file = grab_file(fname, &size);
@@ -2465,9 +2460,9 @@ static void read_dump(const char *fname, unsigned int kernel)
 				have_vmlinux = 1;
 			mod = new_module(modname);
 			mod->skip = 1;
+			mod->from_dump = 1;
 		}
 		s = sym_add_exported(symname, mod, export_no(export));
-		s->kernel    = kernel;
 		s->is_static = 0;
 		sym_set_crc(symname, crc);
 		sym_update_namespace(symname, namespace);
@@ -2487,7 +2482,7 @@ static int dump_sym(struct symbol *sym)
 {
 	if (!external_module)
 		return 1;
-	if (sym->vmlinux || sym->kernel)
+	if (sym->module->from_dump)
 		return 0;
 	return 1;
 }
@@ -2606,11 +2601,11 @@ int main(int argc, char **argv)
 	}
 
 	if (kernel_read)
-		read_dump(kernel_read, 1);
+		read_dump(kernel_read);
 	while (extsym_start) {
 		struct ext_sym_list *tmp;
 
-		read_dump(extsym_start->file, 0);
+		read_dump(extsym_start->file);
 		tmp = extsym_start->next;
 		free(extsym_start);
 		extsym_start = tmp;

scripts/mod/modpost.h

@@ -119,6 +119,7 @@ struct module {
 	const char *name;
 	int gpl_compatible;
 	struct symbol *unres;
+	int from_dump;  /* 1 if module was loaded from *.symvers */
 	int seen;
 	int skip;
 	int has_init;