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Commit 414fd31b authored by Tim Abbott's avatar Tim Abbott Committed by Rusty Russell
Browse files

module: Make find_symbol return a struct kernel_symbol 



Impact: Cleanup, internal API change

Ksplice needs access to the kernel_symbol structure in order to support
modifications to the exported symbol table.

Cc: Anders Kaseorg <andersk@mit.edu>
Cc: Jeff Arnold <jbarnold@mit.edu>
Signed-off-by: default avatarTim Abbott <tabbott@mit.edu>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (bugfix and style)
parent b10153fe

kernel/module.c

+37 −38
Original line number Diff line number Diff line
@@ -283,7 +283,7 @@ struct find_symbol_arg { 
	/* Output */

	struct module *owner;

	const unsigned long *crc;

	unsigned long value;

	const struct kernel_symbol *sym;

};



static bool find_symbol_in_section(const struct symsearch *syms,
@@ -324,13 +324,13 @@ static bool find_symbol_in_section(const struct symsearch *syms, 


	fsa->owner = owner;

	fsa->crc = symversion(syms->crcs, symnum);

	fsa->value = syms->start[symnum].value;

	fsa->sym = &syms->start[symnum];

	return true;

}



/* Find a symbol, return value, (optional) crc and (optional) module

 * which owns it */

static unsigned long find_symbol(const char *name,

/* 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,

					       struct module **owner,

					       const unsigned long **crc,

					       bool gplok,
@@ -347,11 +347,11 @@ static unsigned long find_symbol(const char *name, 
			*owner = fsa.owner;

		if (crc)

			*crc = fsa.crc;

		return fsa.value;

		return fsa.sym;

	}



	DEBUGP("Failed to find symbol %s\n", name);

	return -ENOENT;

	return NULL;

}



/* Search for module by name: must hold module_mutex. */
@@ -894,7 +894,7 @@ void __symbol_put(const char *symbol) 
	struct module *owner;



	preempt_disable();

	if (IS_ERR_VALUE(find_symbol(symbol, &owner, NULL, true, false)))

	if (!find_symbol(symbol, &owner, NULL, true, false))

		BUG();

	module_put(owner);

	preempt_enable();
@@ -1057,7 +1057,7 @@ static inline int check_modstruct_version(Elf_Shdr *sechdrs, 
{

	const unsigned long *crc;



	if (IS_ERR_VALUE(find_symbol("struct_module", NULL, &crc, true, false)))

	if (!find_symbol("struct_module", NULL, &crc, true, false))

		BUG();

	return check_version(sechdrs, versindex, "struct_module", mod, crc);

}
@@ -1098,25 +1098,25 @@ static inline int same_magic(const char *amagic, const char *bmagic, 


/* Resolve a symbol for this module.  I.e. if we find one, record usage.

   Must be holding module_mutex. */

static unsigned long resolve_symbol(Elf_Shdr *sechdrs,

static const struct kernel_symbol *resolve_symbol(Elf_Shdr *sechdrs,

						  unsigned int versindex,

						  const char *name,

						  struct module *mod)

{

	struct module *owner;

	unsigned long ret;

	const struct kernel_symbol *sym;

	const unsigned long *crc;



	ret = find_symbol(name, &owner, &crc,

	sym = find_symbol(name, &owner, &crc,

			  !(mod->taints & (1 << TAINT_PROPRIETARY_MODULE)), true);

	if (!IS_ERR_VALUE(ret)) {

	/* use_module can fail due to OOM,

	   or module initialization or unloading */

	if (sym) {

		if (!check_version(sechdrs, versindex, name, mod, crc) ||

		    !use_module(mod, owner))

			ret = -EINVAL;

			sym = NULL;

	}

	return ret;

	return sym;

}



/*
@@ -1516,17 +1516,15 @@ static void free_module(struct module *mod) 
void *__symbol_get(const char *symbol)

{

	struct module *owner;

	unsigned long value;

	const struct kernel_symbol *sym;



	preempt_disable();

	value = find_symbol(symbol, &owner, NULL, true, true);

	if (IS_ERR_VALUE(value))

		value = 0;

	else if (strong_try_module_get(owner))

		value = 0;

	sym = find_symbol(symbol, &owner, NULL, true, true);

	if (sym && strong_try_module_get(owner))

		sym = NULL;

	preempt_enable();



	return (void *)value;

	return sym ? (void *)sym->value : NULL;

}

EXPORT_SYMBOL_GPL(__symbol_get);
@@ -1554,8 +1552,7 @@ static int verify_export_symbols(struct module *mod) 


	for (i = 0; i < ARRAY_SIZE(arr); i++) {

		for (s = arr[i].sym; s < arr[i].sym + arr[i].num; s++) {

			if (!IS_ERR_VALUE(find_symbol(s->name, &owner,

						      NULL, true, false))) {

			if (find_symbol(s->name, &owner, NULL, true, false)) {

				printk(KERN_ERR

				       "%s: exports duplicate symbol %s"

				       " (owned by %s)\n",
@@ -1579,6 +1576,7 @@ static int simplify_symbols(Elf_Shdr *sechdrs, 
	unsigned long secbase;

	unsigned int i, n = sechdrs[symindex].sh_size / sizeof(Elf_Sym);

	int ret = 0;

	const struct kernel_symbol *ksym;



	for (i = 1; i < n; i++) {

		switch (sym[i].st_shndx) {
@@ -1598,13 +1596,14 @@ static int simplify_symbols(Elf_Shdr *sechdrs, 
			break;



		case SHN_UNDEF:

			sym[i].st_value

			  = resolve_symbol(sechdrs, versindex,

			ksym = resolve_symbol(sechdrs, versindex,

					      strtab + sym[i].st_name, mod);



			/* Ok if resolved.  */

			if (!IS_ERR_VALUE(sym[i].st_value))

			if (ksym) {

				sym[i].st_value = ksym->value;

				break;

			}



			/* Ok if weak.  */

			if (ELF_ST_BIND(sym[i].st_info) == STB_WEAK)

				break;