linux/export.h: make <linux/export.h> independent of CONFIG_MODULES

Currently, all files with EXPORT_SYMBOL() are rebuilt when CONFIG_MODULES
is flipped due to <linux/export.h> depending on CONFIG_MODULES.

Now that modpost can make a final decision about export symbols,
<linux/export.h> does not need to make EXPORT_SYMBOL() no-op.
Instead, modpost can skip emitting KSYMTAB when CONFIG_MODULES is unset.

This commit will reduce the number of recompilation when CONFIG_MODULES
is toggled.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

diff --git a/include/linux/export.h b/include/linux/export.h
index beed838..9911508 100644 (file)
--- a/include/linux/export.h
+++ b/include/linux/export.h
@@ -50,7 +50,7 @@ extern struct module __this_module;
                __EXPORT_SYMBOL_REF(sym)        ASM_NL  \
        .previous
 
-#if !defined(CONFIG_MODULES) || defined(__DISABLE_EXPORTS)
+#if defined(__DISABLE_EXPORTS)
 
 /*
  * Allow symbol exports to be disabled completely so that C code may
@@ -75,7 +75,7 @@ extern struct module __this_module;
        __ADDRESSABLE(sym)                                      \
        asm(__stringify(___EXPORT_SYMBOL(sym, license, ns)))
 
-#endif /* CONFIG_MODULES */
+#endif
 
 #ifdef DEFAULT_SYMBOL_NAMESPACE
 #define _EXPORT_SYMBOL(sym, license)   __EXPORT_SYMBOL(sym, license, __stringify(DEFAULT_SYMBOL_NAMESPACE))

diff --git a/scripts/Makefile.modpost b/scripts/Makefile.modpost
index 39472e8..739402f 100644 (file)
--- a/scripts/Makefile.modpost
+++ b/scripts/Makefile.modpost
@@ -41,6 +41,7 @@ include $(srctree)/scripts/Kbuild.include
 MODPOST = scripts/mod/modpost
 
 modpost-args =                                                                         \
+       $(if $(CONFIG_MODULES),-M)                                                      \
        $(if $(CONFIG_MODVERSIONS),-m)                                                  \
        $(if $(CONFIG_MODULE_SRCVERSION_ALL),-a)                                        \
        $(if $(CONFIG_SECTION_MISMATCH_WARN_ONLY),,-E)                                  \

diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index b29b297..8227641 100644 (file)
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -24,6 +24,7 @@
 #include "../../include/linux/license.h"
 #include "../../include/linux/module_symbol.h"
 
+static bool module_enabled;
 /* Are we using CONFIG_MODVERSIONS? */
 static bool modversions;
 /* Is CONFIG_MODULE_SRCVERSION_ALL set? */
@@ -1242,7 +1243,7 @@ static void check_section_mismatch(struct module *mod, struct elf_info *elf,
        const char *tosec = sec_name(elf, get_secindex(elf, sym));
        const struct sectioncheck *mismatch;
 
-       if (elf->export_symbol_secndx == fsecndx) {
+       if (module_enabled && elf->export_symbol_secndx == fsecndx) {
                check_export_symbol(mod, elf, faddr, tosec, sym);
                return;
        }
@@ -2272,7 +2273,7 @@ int main(int argc, char **argv)
        LIST_HEAD(dump_lists);
        struct dump_list *dl, *dl2;
 
-       while ((opt = getopt(argc, argv, "ei:mnT:to:au:WwENd:")) != -1) {
+       while ((opt = getopt(argc, argv, "ei:MmnT:to:au:WwENd:")) != -1) {
                switch (opt) {
                case 'e':
                        external_module = true;
@@ -2282,6 +2283,9 @@ int main(int argc, char **argv)
                        dl->file = optarg;
                        list_add_tail(&dl->list, &dump_lists);
                        break;
+               case 'M':
+                       module_enabled = true;
+                       break;
                case 'm':
                        modversions = true;
                        break;