[PATCH] module names fix

By Kai Germaschewski:

 "Well, I have another solution, which doesn't need additional Makefile
  magic or anything.

  I just put the module name into each .o file where <linux/module.h> is
  included. Putting it into the section .gnu.linkonce.modname has the effect
  that even for multi-part modules, we only end up with one copy of the
  name.

  Caveat: I'm using the preprocessor macro KBUILD_MODNAME to know what to
  put into .gnu.linkonce.modname. The following used to happen:

  (drivers/isdn/eicon/Makefile)

  divas-objs := common.o Divas_mod.o ...
  eicon-objs := common.o eicon_mod.o ...

  Divas_mod.o is compiled with -DKBUILD_MODNAME=divas
  eicon_mod.o is compiled with -DKBUILD_MODNAME=eicon
  common.o is compiled with -DKBUILD_MODNAME=divas_eicon

  So in the case above, both divas.o and eicon.o would end up with
  a .gnu.linkonce.modname section containing "divas_eicon"

  My fix to this is to not define KBUILD_MODNAME when compiling an object
  whilch will be linked into more than one module - so common.o gets no
  .gnu.linkonce.modname section at all. Works fine here.

  Now, doing this I remove one of the reasons why we would need modules
  linked as '.ko' ;), but it seems much cleaner than generating a temporary
  file, using objcopy etc."

include/linux/init.h

@@ -125,14 +125,6 @@ extern struct kernel_param __setup_start, __setup_end;
  */
 #define module_exit(x)	__exitcall(x);
 
-/**
- * no_module_init - code needs no initialization.
- *
- * The equivalent of declaring an empty init function which returns 0.
- * Every module must have exactly one module_init() or no_module_init
- * invocation.  */
-#define no_module_init
-
 #else /* MODULE */
 
 /* Don't use these in modules, but some people do... */
@@ -144,11 +136,6 @@ extern struct kernel_param __setup_start, __setup_end;
 #define device_initcall(fn)		module_init(fn)
 #define late_initcall(fn)		module_init(fn)
 
-/* Each module knows its own name. */
-#define __DEFINE_MODULE_NAME						\
-	char __module_name[] __attribute__((section(".modulename"))) =	\
-	__stringify(KBUILD_MODNAME)
-
 /* These macros create a dummy inline: gcc 2.9x does not count alias
  as usage, hence the `unused function' warning when __init functions
  are declared static. We use the dummy __*_module_inline functions
@@ -157,13 +144,10 @@ extern struct kernel_param __setup_start, __setup_end;
 
 /* Each module must use one module_init(), or one no_module_init */
 #define module_init(initfn)					\
-	__DEFINE_MODULE_NAME;					\
 	static inline initcall_t __inittest(void)		\
 	{ return initfn; }					\
 	int __initfn(void) __attribute__((alias(#initfn)));
 
-#define no_module_init __DEFINE_MODULE_NAME
-
 /* This is only required if you want to be unloadable. */
 #define module_exit(exitfn)					\
 	static inline exitcall_t __exittest(void)		\

include/linux/module.h

@@ -46,6 +46,11 @@ struct kernel_symbol
 
 #ifdef MODULE
 
+#ifdef KBUILD_MODNAME
+static const char __module_name[MODULE_NAME_LEN] __attribute__((section(".gnu.linkonce.modname"))) = \
+  __stringify(KBUILD_MODNAME);
+#endif
+
 /* For replacement modutils, use an alias not a pointer. */
 #define MODULE_GENERIC_TABLE(gtype,name)			\
 static const unsigned long __module_##gtype##_size		\
@@ -315,12 +320,7 @@ extern int module_dummy_usage;
 /* Old-style "I'll just call it init_module and it'll be run at
    insert".  Use module_init(myroutine) instead. */
 #ifdef MODULE
-/* Used as "int init_module(void) { ... }".  Get funky to insert modname. */
-#define init_module(voidarg)						\
-	__initfn(void);							\
-	char __module_name[] __attribute__((section(".modulename"))) =	\
-	__stringify(KBUILD_MODNAME);					\
-	int __initfn(void)
+#define init_module(voidarg) __initfn(void)
 #define cleanup_module(voidarg) __exitfn(void)
 #endif
 

kernel/module.c

@@ -867,8 +867,8 @@ static struct module *load_module(void *umod,
 			/* Internal symbols */
 			DEBUGP("Symbol table in section %u\n", i);
 			symindex = i;
-		} else if (strcmp(secstrings+sechdrs[i].sh_name, ".modulename")
-			   == 0) {
+		} else if (strcmp(secstrings+sechdrs[i].sh_name,
+				  ".gnu.linkonce.modname") == 0) {
 			/* This module's name */
 			DEBUGP("Module name in section %u\n", i);
 			modnameindex = i;

lib/zlib_deflate/deflate_syms.c

@@ -19,5 +19,3 @@ EXPORT_SYMBOL(zlib_deflateReset);
 EXPORT_SYMBOL(zlib_deflateCopy);
 EXPORT_SYMBOL(zlib_deflateParams);
 MODULE_LICENSE("GPL");
-
-no_module_init;

lib/zlib_inflate/inflate_syms.c

@@ -20,5 +20,3 @@ EXPORT_SYMBOL(zlib_inflateReset);
 EXPORT_SYMBOL(zlib_inflateSyncPoint);
 EXPORT_SYMBOL(zlib_inflateIncomp); 
 MODULE_LICENSE("GPL");
-
-no_module_init;

scripts/Makefile.lib

@@ -124,14 +124,14 @@ depfile = $(subst $(comma),_,$(@D)/.$(@F).d)
 #       than one module. In that case KBUILD_MODNAME will be set to foo_bar,
 #       where foo and bar are the name of the modules.
 basename_flags = -DKBUILD_BASENAME=$(subst $(comma),_,$(subst -,_,$(*F)))
-modname_flags  = -DKBUILD_MODNAME=$(subst $(comma),_,$(subst -,_,$(modname)))
+modname_flags  = $(if $(filter 1,$(words $(modname))),-DKBUILD_MODNAME=$(subst $(comma),_,$(subst -,_,$(modname))))
 c_flags        = -Wp,-MD,$(depfile) $(CFLAGS) $(NOSTDINC_FLAGS) \
 	         $(modkern_cflags) $(EXTRA_CFLAGS) $(CFLAGS_$(*F).o) \
 	         $(basename_flags) $(modname_flags) $(export_flags) 
 
 # Finds the multi-part object the current object will be linked into
-modname-multi = $(subst $(space),_,$(sort $(foreach m,$(multi-used),\
-		$(if $(filter $(subst $(obj)/,,$*.o), $($(m:.o=-objs)) $($(m:.o=-y))),$(m:.o=)))))
+modname-multi = $(sort $(foreach m,$(multi-used),\
+		$(if $(filter $(subst $(obj)/,,$*.o), $($(m:.o=-objs)) $($(m:.o=-y))),$(m:.o=))))
 
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