Commit e610499e authored by Rusty Russell's avatar Rusty Russell
Browse files

module: __module_address 



Impact: New API, cleanup

ksplice wants to know the bounds of a module, not just the module text.

It makes sense to have __module_address.  We then implement
is_module_address and __module_text_address in terms of this (and
change is_module_text_address() to bool while we're at it).

Also, add proper kerneldoc for them all.

Cc: Anders Kaseorg <andersk@mit.edu>
Cc: Jeff Arnold <jbarnold@mit.edu>
Cc: Tim Abbott <tabbott@mit.edu>
Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
parent 414fd31b

include/linux/module.h

+15 −5
Original line number Diff line number Diff line
@@ -365,7 +365,9 @@ static inline int module_is_live(struct module *mod) 
/* Is this address in a module? (second is with no locks, for oops) */

struct module *module_text_address(unsigned long addr);

struct module *__module_text_address(unsigned long addr);

int is_module_address(unsigned long addr);

struct module *__module_address(unsigned long addr);

bool is_module_address(unsigned long addr);

bool is_module_text_address(unsigned long addr);



static inline int within_module_core(unsigned long addr, struct module *mod)

{
@@ -494,21 +496,29 @@ search_module_extables(unsigned long addr) 
	return NULL;

}



/* Is this address in a module? */

static inline struct module *module_text_address(unsigned long addr)

{

	return NULL;

}



/* Is this address in a module? (don't take a lock, we're oopsing) */

static inline struct module *__module_address(unsigned long addr)

{

	return NULL;

}



static inline struct module *__module_text_address(unsigned long addr)

{

	return NULL;

}



static inline int is_module_address(unsigned long addr)

static inline bool is_module_address(unsigned long addr)

{

	return 0;

	return false;

}



static inline bool is_module_text_address(unsigned long addr)

{

	return false;

}



/* Get/put a kernel symbol (calls should be symmetric) */

kernel/module.c

+58 −18
Original line number Diff line number Diff line
@@ -76,7 +76,7 @@ static DECLARE_WAIT_QUEUE_HEAD(module_wq); 


static BLOCKING_NOTIFIER_HEAD(module_notify_list);



/* Bounds of module allocation, for speeding __module_text_address */

/* Bounds of module allocation, for speeding __module_address */

static unsigned long module_addr_min = -1UL, module_addr_max = 0;



int register_module_notifier(struct notifier_block * nb)
@@ -2745,29 +2745,31 @@ const struct exception_table_entry *search_module_extables(unsigned long addr) 
}



/*

 * Is this a valid module address?

 * is_module_address - is this address inside a module?

 * @addr: the address to check.

 *

 * See is_module_text_address() if you simply want to see if the address

 * is code (not data).

 */

int is_module_address(unsigned long addr)

bool is_module_address(unsigned long addr)

{

	struct module *mod;

	bool ret;



	preempt_disable();



	list_for_each_entry_rcu(mod, &modules, list) {

		if (within_module_core(addr, mod)) {

			preempt_enable();

			return 1;

		}

	}



	ret = __module_address(addr) != NULL;

	preempt_enable();



	return 0;

	return ret;

}





/* Is this a valid kernel address? */

__notrace_funcgraph struct module *__module_text_address(unsigned long addr)

/*

 * __module_address - get the module which contains an address.

 * @addr: the address.

 *

 * Must be called with preempt disabled or module mutex held so that

 * module doesn't get freed during this.

 */

__notrace_funcgraph struct module *__module_address(unsigned long addr)

{

	struct module *mod;
@@ -2775,12 +2777,50 @@ __notrace_funcgraph struct module *__module_text_address(unsigned long addr) 
		return NULL;



	list_for_each_entry_rcu(mod, &modules, list)

		if (within(addr, mod->module_init, mod->init_text_size)

		    || within(addr, mod->module_core, mod->core_text_size))

		if (within_module_core(addr, mod)

		    || within_module_init(addr, mod))

			return mod;

	return NULL;

}



/*

 * is_module_text_address - is this address inside module code?

 * @addr: the address to check.

 *

 * See is_module_address() if you simply want to see if the address is

 * anywhere in a module.  See kernel_text_address() for testing if an

 * address corresponds to kernel or module code.

 */

bool is_module_text_address(unsigned long addr)

{

	bool ret;



	preempt_disable();

	ret = __module_text_address(addr) != NULL;

	preempt_enable();



	return ret;

}



/*

 * __module_text_address - get the module whose code contains an address.

 * @addr: the address.

 *

 * Must be called with preempt disabled or module mutex held so that

 * module doesn't get freed during this.

 */

struct module *__module_text_address(unsigned long addr)

{

	struct module *mod = __module_address(addr);

	if (mod) {

		/* Make sure it's within the text section. */

		if (!within(addr, mod->module_init, mod->init_text_size)

		    && !within(addr, mod->module_core, mod->core_text_size))

			mod = NULL;

	}

	return mod;

}



struct module *module_text_address(unsigned long addr)

{

	struct module *mod;

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