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Commit c6b37801 authored by Tim Abbott's avatar Tim Abbott Committed by Rusty Russell
Browse files

module: Export symbols needed for Ksplice 



Impact: Expose some module.c symbols

Ksplice uses several functions from module.c in order to resolve
symbols and implement dependency handling.  Calling these functions
requires holding module_mutex, so it is exported.

(This is just the module part of a bigger add-exports patch from Tim).

Cc: Anders Kaseorg <andersk@mit.edu>
Cc: Jeff Arnold <jbarnold@mit.edu>
Signed-off-by: default avatarTim Abbott <tabbott@mit.edu>
Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
parent 75a66614

include/linux/module.h

+28 −0
Original line number Diff line number Diff line
@@ -354,6 +354,8 @@ struct module 
#define MODULE_ARCH_INIT {}

#endif



extern struct mutex module_mutex;



/* FIXME: It'd be nice to isolate modules during init, too, so they

   aren't used before they (may) fail.  But presently too much code

   (IDE & SCSI) require entry into the module during init.*/
@@ -379,6 +381,31 @@ static inline int within_module_init(unsigned long addr, struct module *mod) 
	       addr < (unsigned long)mod->module_init + mod->init_size;

}



/* Search for module by name: must hold module_mutex. */

struct module *find_module(const char *name);



struct symsearch {

	const struct kernel_symbol *start, *stop;

	const unsigned long *crcs;

	enum {

		NOT_GPL_ONLY,

		GPL_ONLY,

		WILL_BE_GPL_ONLY,

	} licence;

	bool unused;

};



/* Search for an exported symbol by name. */

const struct kernel_symbol *find_symbol(const char *name,

					struct module **owner,

					const unsigned long **crc,

					bool gplok,

					bool warn);



/* Walk the exported symbol table */

bool each_symbol(bool (*fn)(const struct symsearch *arr, struct module *owner,

			    unsigned int symnum, void *data), void *data);



/* Returns 0 and fills in value, defined and namebuf, or -ERANGE if

   symnum out of range. */

int module_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
@@ -452,6 +479,7 @@ static inline void __module_get(struct module *module) 
#define symbol_put_addr(p) do { } while(0)



#endif /* CONFIG_MODULE_UNLOAD */

int use_module(struct module *a, struct module *b);



/* This is a #define so the string doesn't get put in every .o file */

#define module_name(mod)			\

kernel/module.c

+19 −24
Original line number Diff line number Diff line
@@ -68,7 +68,8 @@ 


/* List of modules, protected by module_mutex or preempt_disable

 * (delete uses stop_machine/add uses RCU list operations). */

static DEFINE_MUTEX(module_mutex);

DEFINE_MUTEX(module_mutex);

EXPORT_SYMBOL_GPL(module_mutex);

static LIST_HEAD(modules);



/* Waiting for a module to finish initializing? */
@@ -186,17 +187,6 @@ extern const unsigned long __start___kcrctab_unused_gpl[]; 
#define symversion(base, idx) ((base != NULL) ? ((base) + (idx)) : NULL)

#endif



struct symsearch {

	const struct kernel_symbol *start, *stop;

	const unsigned long *crcs;

	enum {

		NOT_GPL_ONLY,

		GPL_ONLY,

		WILL_BE_GPL_ONLY,

	} licence;

	bool unused;

};



static bool each_symbol_in_section(const struct symsearch *arr,

				   unsigned int arrsize,

				   struct module *owner,
@@ -217,10 +207,8 @@ static bool each_symbol_in_section(const struct symsearch *arr, 
}



/* Returns true as soon as fn returns true, otherwise false. */

static bool each_symbol(bool (*fn)(const struct symsearch *arr,

				   struct module *owner,

				   unsigned int symnum, void *data),

			void *data)

bool each_symbol(bool (*fn)(const struct symsearch *arr, struct module *owner,

			    unsigned int symnum, void *data), void *data)

{

	struct module *mod;

	const struct symsearch arr[] = {
@@ -273,6 +261,7 @@ static bool each_symbol(bool (*fn)(const struct symsearch *arr, 
	}

	return false;

}

EXPORT_SYMBOL_GPL(each_symbol);



struct find_symbol_arg {

	/* Input */
@@ -330,7 +319,7 @@ static bool find_symbol_in_section(const struct symsearch *syms, 


/* Find a symbol and return it, along with, (optional) crc and

 * (optional) module which owns it */

static const struct kernel_symbol *find_symbol(const char *name,

const struct kernel_symbol *find_symbol(const char *name,

					struct module **owner,

					const unsigned long **crc,

					bool gplok,
@@ -353,9 +342,10 @@ static const struct kernel_symbol *find_symbol(const char *name, 
	DEBUGP("Failed to find symbol %s\n", name);

	return NULL;

}

EXPORT_SYMBOL_GPL(find_symbol);



/* Search for module by name: must hold module_mutex. */

static struct module *find_module(const char *name)

struct module *find_module(const char *name)

{

	struct module *mod;
@@ -365,6 +355,7 @@ static struct module *find_module(const char *name) 
	}

	return NULL;

}

EXPORT_SYMBOL_GPL(find_module);



#ifdef CONFIG_SMP
@@ -641,7 +632,7 @@ static int already_uses(struct module *a, struct module *b) 
}



/* Module a uses b */

static int use_module(struct module *a, struct module *b)

int use_module(struct module *a, struct module *b)

{

	struct module_use *use;

	int no_warn, err;
@@ -674,6 +665,7 @@ static int use_module(struct module *a, struct module *b) 
	no_warn = sysfs_create_link(b->holders_dir, &a->mkobj.kobj, a->name);

	return 1;

}

EXPORT_SYMBOL_GPL(use_module);



/* Clear the unload stuff of the module. */

static void module_unload_free(struct module *mod)
@@ -951,10 +943,11 @@ static inline void module_unload_free(struct module *mod) 
{

}



static inline int use_module(struct module *a, struct module *b)

int use_module(struct module *a, struct module *b)

{

	return strong_try_module_get(b) == 0;

}

EXPORT_SYMBOL_GPL(use_module);



static inline void module_unload_init(struct module *mod)

{
@@ -2803,6 +2796,7 @@ __notrace_funcgraph struct module *__module_address(unsigned long addr) 
			return mod;

	return NULL;

}

EXPORT_SYMBOL_GPL(__module_address);



/*

 * is_module_text_address - is this address inside module code?
@@ -2841,6 +2835,7 @@ struct module *__module_text_address(unsigned long addr) 
	}

	return mod;

}

EXPORT_SYMBOL_GPL(__module_text_address);



/* Don't grab lock, we're oopsing. */

void print_modules(void)