kbuild: warn when a moduled uses a symbol marked UNUSED
We now have infrastructure in place to mark an EXPORTed symbol
as unused. So the natural next step is to warn during buildtime when
a module uses a symbol marked UNUSED.
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index 6541166..dfde0e8 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -24,7 +24,10 @@
/* If we are modposting external module set to 1 */
static int external_module = 0;
/* How a symbol is exported */
-enum export {export_plain, export_gpl, export_gpl_future, export_unknown};
+enum export {
+ export_plain, export_unused, export_gpl,
+ export_unused_gpl, export_gpl_future, export_unknown
+};
void fatal(const char *fmt, ...)
{
@@ -191,7 +194,9 @@
enum export export;
} export_list[] = {
{ .str = "EXPORT_SYMBOL", .export = export_plain },
+ { .str = "EXPORT_UNUSED_SYMBOL", .export = export_unused },
{ .str = "EXPORT_SYMBOL_GPL", .export = export_gpl },
+ { .str = "EXPORT_UNUSED_SYMBOL_GPL", .export = export_unused_gpl },
{ .str = "EXPORT_SYMBOL_GPL_FUTURE", .export = export_gpl_future },
{ .str = "(unknown)", .export = export_unknown },
};
@@ -218,8 +223,12 @@
{
if (sec == elf->export_sec)
return export_plain;
+ else if (sec == elf->export_unused_sec)
+ return export_unused;
else if (sec == elf->export_gpl_sec)
return export_gpl;
+ else if (sec == elf->export_unused_gpl_sec)
+ return export_unused_gpl;
else if (sec == elf->export_gpl_future_sec)
return export_gpl_future;
else
@@ -368,8 +377,12 @@
info->modinfo_len = sechdrs[i].sh_size;
} else if (strcmp(secname, "__ksymtab") == 0)
info->export_sec = i;
+ else if (strcmp(secname, "__ksymtab_unused") == 0)
+ info->export_unused_sec = i;
else if (strcmp(secname, "__ksymtab_gpl") == 0)
info->export_gpl_sec = i;
+ else if (strcmp(secname, "__ksymtab_unused_gpl") == 0)
+ info->export_unused_gpl_sec = i;
else if (strcmp(secname, "__ksymtab_gpl_future") == 0)
info->export_gpl_future_sec = i;
@@ -1087,38 +1100,64 @@
buf->pos += len;
}
-void check_license(struct module *mod)
+static void check_for_gpl_usage(enum export exp, const char *m, const char *s)
+{
+ const char *e = is_vmlinux(m) ?"":".ko";
+
+ switch (exp) {
+ case export_gpl:
+ fatal("modpost: GPL-incompatible module %s%s "
+ "uses GPL-only symbol '%s'\n", m, e, s);
+ break;
+ case export_unused_gpl:
+ fatal("modpost: GPL-incompatible module %s%s "
+ "uses GPL-only symbol marked UNUSED '%s'\n", m, e, s);
+ break;
+ case export_gpl_future:
+ warn("modpost: GPL-incompatible module %s%s "
+ "uses future GPL-only symbol '%s'\n", m, e, s);
+ break;
+ case export_plain:
+ case export_unused:
+ case export_unknown:
+ /* ignore */
+ break;
+ }
+}
+
+static void check_for_unused(enum export exp, const char* m, const char* s)
+{
+ const char *e = is_vmlinux(m) ?"":".ko";
+
+ switch (exp) {
+ case export_unused:
+ case export_unused_gpl:
+ warn("modpost: module %s%s "
+ "uses symbol '%s' marked UNUSED\n", m, e, s);
+ break;
+ default:
+ /* ignore */
+ break;
+ }
+}
+
+static void check_exports(struct module *mod)
{
struct symbol *s, *exp;
for (s = mod->unres; s; s = s->next) {
const char *basename;
- if (mod->gpl_compatible == 1) {
- /* GPL-compatible modules may use all symbols */
- continue;
- }
exp = find_symbol(s->name);
if (!exp || exp->module == mod)
continue;
basename = strrchr(mod->name, '/');
if (basename)
basename++;
- switch (exp->export) {
- case export_gpl:
- fatal("modpost: GPL-incompatible module %s "
- "uses GPL-only symbol '%s'\n",
- basename ? basename : mod->name,
- exp->name);
- break;
- case export_gpl_future:
- warn("modpost: GPL-incompatible module %s "
- "uses future GPL-only symbol '%s'\n",
- basename ? basename : mod->name,
- exp->name);
- break;
- case export_plain: /* ignore */ break;
- case export_unknown: /* ignore */ break;
- }
+ else
+ basename = mod->name;
+ if (!mod->gpl_compatible)
+ check_for_gpl_usage(exp->export, basename, exp->name);
+ check_for_unused(exp->export, basename, exp->name);
}
}
@@ -1399,7 +1438,7 @@
for (mod = modules; mod; mod = mod->next) {
if (mod->skip)
continue;
- check_license(mod);
+ check_exports(mod);
}
for (mod = modules; mod; mod = mod->next) {
diff --git a/scripts/mod/modpost.h b/scripts/mod/modpost.h
index 2b00c60..d398c61 100644
--- a/scripts/mod/modpost.h
+++ b/scripts/mod/modpost.h
@@ -117,7 +117,9 @@
Elf_Sym *symtab_start;
Elf_Sym *symtab_stop;
Elf_Section export_sec;
+ Elf_Section export_unused_sec;
Elf_Section export_gpl_sec;
+ Elf_Section export_unused_gpl_sec;
Elf_Section export_gpl_future_sec;
const char *strtab;
char *modinfo;