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Commit 75a66614 authored by Anders Kaseorg's avatar Anders Kaseorg Committed by Rusty Russell
Browse files

Ksplice: Add functions for walking kallsyms symbols 



Impact: New API

kallsyms_lookup_name only returns the first match that it finds.  Ksplice
needs information about all symbols with a given name in order to correctly
resolve local symbols.

kallsyms_on_each_symbol provides a generic mechanism for iterating over the
kallsyms table.

Cc: Jeff Arnold <jbarnold@mit.edu>
Cc: Tim Abbott <tabbott@mit.edu>
Signed-off-by: default avatarAnders Kaseorg <andersk@mit.edu>
Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
parent a6e6abd5

include/linux/kallsyms.h

+15 −0
Original line number Diff line number Diff line
@@ -13,10 +13,17 @@ 
#define KSYM_SYMBOL_LEN (sizeof("%s+%#lx/%#lx [%s]") + (KSYM_NAME_LEN - 1) + \

			 2*(BITS_PER_LONG*3/10) + (MODULE_NAME_LEN - 1) + 1)



struct module;



#ifdef CONFIG_KALLSYMS

/* Lookup the address for a symbol. Returns 0 if not found. */

unsigned long kallsyms_lookup_name(const char *name);



/* Call a function on each kallsyms symbol in the core kernel */

int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *,

				      unsigned long),

			    void *data);



extern int kallsyms_lookup_size_offset(unsigned long addr,

				  unsigned long *symbolsize,

				  unsigned long *offset);
@@ -43,6 +50,14 @@ static inline unsigned long kallsyms_lookup_name(const char *name) 
	return 0;

}



static inline int kallsyms_on_each_symbol(int (*fn)(void *, const char *,

						    struct module *,

						    unsigned long),

					  void *data)

{

	return 0;

}



static inline int kallsyms_lookup_size_offset(unsigned long addr,

					      unsigned long *symbolsize,

					      unsigned long *offset)

include/linux/module.h

+12 −0
Original line number Diff line number Diff line
@@ -387,6 +387,10 @@ int module_get_kallsym(unsigned int symnum, unsigned long *value, char *type, 
/* Look for this name: can be of form module:name. */

unsigned long module_kallsyms_lookup_name(const char *name);



int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,

					     struct module *, unsigned long),

				   void *data);



extern void __module_put_and_exit(struct module *mod, long code)

	__attribute__((noreturn));

#define module_put_and_exit(code) __module_put_and_exit(THIS_MODULE, code);
@@ -566,6 +570,14 @@ static inline unsigned long module_kallsyms_lookup_name(const char *name) 
	return 0;

}



static inline int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,

							   struct module *,

							   unsigned long),

						 void *data)

{

	return 0;

}



static inline int register_module_notifier(struct notifier_block * nb)

{

	/* no events will happen anyway, so this can always succeed */

kernel/kallsyms.c

+19 −0
Original line number Diff line number Diff line
@@ -161,6 +161,25 @@ unsigned long kallsyms_lookup_name(const char *name) 
	return module_kallsyms_lookup_name(name);

}



int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *,

				      unsigned long),

			    void *data)

{

	char namebuf[KSYM_NAME_LEN];

	unsigned long i;

	unsigned int off;

	int ret;



	for (i = 0, off = 0; i < kallsyms_num_syms; i++) {

		off = kallsyms_expand_symbol(off, namebuf);

		ret = fn(data, namebuf, NULL, kallsyms_addresses[i]);

		if (ret != 0)

			return ret;

	}

	return module_kallsyms_on_each_symbol(fn, data);

}

EXPORT_SYMBOL_GPL(kallsyms_on_each_symbol);



static unsigned long get_symbol_pos(unsigned long addr,

				    unsigned long *symbolsize,

				    unsigned long *offset)

kernel/module.c

+19 −0
Original line number Diff line number Diff line
@@ -2612,6 +2612,25 @@ unsigned long module_kallsyms_lookup_name(const char *name) 
	preempt_enable();

	return ret;

}



int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,

					     struct module *, unsigned long),

				   void *data)

{

	struct module *mod;

	unsigned int i;

	int ret;



	list_for_each_entry(mod, &modules, list) {

		for (i = 0; i < mod->num_symtab; i++) {

			ret = fn(data, mod->strtab + mod->symtab[i].st_name,

				 mod, mod->symtab[i].st_value);

			if (ret != 0)

				return ret;

		}

	}

	return 0;

}

#endif /* CONFIG_KALLSYMS */



static char *module_flags(struct module *mod, char *buf)