linux-stable/include/linux/module.h
Dan Streetman b51d23e4e9 module: add per-module param_lock
Add a "param_lock" mutex to each module, and update params.c to use
the correct built-in or module mutex while locking kernel params.
Remove the kparam_block_sysfs_r/w() macros, replace them with direct
calls to kernel_param_[un]lock(module).

The kernel param code currently uses a single mutex to protect
modification of any and all kernel params.  While this generally works,
there is one specific problem with it; a module callback function
cannot safely load another module, i.e. with request_module() or even
with indirect calls such as crypto_has_alg().  If the module to be
loaded has any of its params configured (e.g. with a /etc/modprobe.d/*
config file), then the attempt will result in a deadlock between the
first module param callback waiting for modprobe, and modprobe trying to
lock the single kernel param mutex to set the new module's param.

This fixes that by using per-module mutexes, so that each individual module
is protected against concurrent changes in its own kernel params, but is
not blocked by changes to other module params.  All built-in modules
continue to use the built-in mutex, since they will always be loaded at
runtime and references (e.g. request_module(), crypto_has_alg()) to them
will never cause load-time param changing.

This also simplifies the interface used by modules to block sysfs access
to their params; while there are currently functions to block and unblock
sysfs param access which are split up by read and write and expect a single
kernel param to be passed, their actual operation is identical and applies
to all params, not just the one passed to them; they simply lock and unlock
the global param mutex.  They are replaced with direct calls to
kernel_param_[un]lock(THIS_MODULE), which locks THIS_MODULE's param_lock, or
if the module is built-in, it locks the built-in mutex.

Suggested-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Dan Streetman <ddstreet@ieee.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2015-06-23 15:27:38 +09:30

692 lines
19 KiB
C

#ifndef _LINUX_MODULE_H
#define _LINUX_MODULE_H
/*
* Dynamic loading of modules into the kernel.
*
* Rewritten by Richard Henderson <rth@tamu.edu> Dec 1996
* Rewritten again by Rusty Russell, 2002
*/
#include <linux/list.h>
#include <linux/stat.h>
#include <linux/compiler.h>
#include <linux/cache.h>
#include <linux/kmod.h>
#include <linux/elf.h>
#include <linux/stringify.h>
#include <linux/kobject.h>
#include <linux/moduleparam.h>
#include <linux/jump_label.h>
#include <linux/export.h>
#include <linux/rbtree_latch.h>
#include <linux/percpu.h>
#include <asm/module.h>
/* In stripped ARM and x86-64 modules, ~ is surprisingly rare. */
#define MODULE_SIG_STRING "~Module signature appended~\n"
/* Not Yet Implemented */
#define MODULE_SUPPORTED_DEVICE(name)
#define MODULE_NAME_LEN MAX_PARAM_PREFIX_LEN
struct modversion_info {
unsigned long crc;
char name[MODULE_NAME_LEN];
};
struct module;
struct module_kobject {
struct kobject kobj;
struct module *mod;
struct kobject *drivers_dir;
struct module_param_attrs *mp;
struct completion *kobj_completion;
};
struct module_attribute {
struct attribute attr;
ssize_t (*show)(struct module_attribute *, struct module_kobject *,
char *);
ssize_t (*store)(struct module_attribute *, struct module_kobject *,
const char *, size_t count);
void (*setup)(struct module *, const char *);
int (*test)(struct module *);
void (*free)(struct module *);
};
struct module_version_attribute {
struct module_attribute mattr;
const char *module_name;
const char *version;
} __attribute__ ((__aligned__(sizeof(void *))));
extern ssize_t __modver_version_show(struct module_attribute *,
struct module_kobject *, char *);
extern struct module_attribute module_uevent;
/* These are either module local, or the kernel's dummy ones. */
extern int init_module(void);
extern void cleanup_module(void);
/* Archs provide a method of finding the correct exception table. */
struct exception_table_entry;
const struct exception_table_entry *
search_extable(const struct exception_table_entry *first,
const struct exception_table_entry *last,
unsigned long value);
void sort_extable(struct exception_table_entry *start,
struct exception_table_entry *finish);
void sort_main_extable(void);
void trim_init_extable(struct module *m);
/* Generic info of form tag = "info" */
#define MODULE_INFO(tag, info) __MODULE_INFO(tag, tag, info)
/* For userspace: you can also call me... */
#define MODULE_ALIAS(_alias) MODULE_INFO(alias, _alias)
/* Soft module dependencies. See man modprobe.d for details.
* Example: MODULE_SOFTDEP("pre: module-foo module-bar post: module-baz")
*/
#define MODULE_SOFTDEP(_softdep) MODULE_INFO(softdep, _softdep)
/*
* The following license idents are currently accepted as indicating free
* software modules
*
* "GPL" [GNU Public License v2 or later]
* "GPL v2" [GNU Public License v2]
* "GPL and additional rights" [GNU Public License v2 rights and more]
* "Dual BSD/GPL" [GNU Public License v2
* or BSD license choice]
* "Dual MIT/GPL" [GNU Public License v2
* or MIT license choice]
* "Dual MPL/GPL" [GNU Public License v2
* or Mozilla license choice]
*
* The following other idents are available
*
* "Proprietary" [Non free products]
*
* There are dual licensed components, but when running with Linux it is the
* GPL that is relevant so this is a non issue. Similarly LGPL linked with GPL
* is a GPL combined work.
*
* This exists for several reasons
* 1. So modinfo can show license info for users wanting to vet their setup
* is free
* 2. So the community can ignore bug reports including proprietary modules
* 3. So vendors can do likewise based on their own policies
*/
#define MODULE_LICENSE(_license) MODULE_INFO(license, _license)
/*
* Author(s), use "Name <email>" or just "Name", for multiple
* authors use multiple MODULE_AUTHOR() statements/lines.
*/
#define MODULE_AUTHOR(_author) MODULE_INFO(author, _author)
/* What your module does. */
#define MODULE_DESCRIPTION(_description) MODULE_INFO(description, _description)
#ifdef MODULE
/* Creates an alias so file2alias.c can find device table. */
#define MODULE_DEVICE_TABLE(type, name) \
extern const typeof(name) __mod_##type##__##name##_device_table \
__attribute__ ((unused, alias(__stringify(name))))
#else /* !MODULE */
#define MODULE_DEVICE_TABLE(type, name)
#endif
/* Version of form [<epoch>:]<version>[-<extra-version>].
* Or for CVS/RCS ID version, everything but the number is stripped.
* <epoch>: A (small) unsigned integer which allows you to start versions
* anew. If not mentioned, it's zero. eg. "2:1.0" is after
* "1:2.0".
* <version>: The <version> may contain only alphanumerics and the
* character `.'. Ordered by numeric sort for numeric parts,
* ascii sort for ascii parts (as per RPM or DEB algorithm).
* <extraversion>: Like <version>, but inserted for local
* customizations, eg "rh3" or "rusty1".
* Using this automatically adds a checksum of the .c files and the
* local headers in "srcversion".
*/
#if defined(MODULE) || !defined(CONFIG_SYSFS)
#define MODULE_VERSION(_version) MODULE_INFO(version, _version)
#else
#define MODULE_VERSION(_version) \
static struct module_version_attribute ___modver_attr = { \
.mattr = { \
.attr = { \
.name = "version", \
.mode = S_IRUGO, \
}, \
.show = __modver_version_show, \
}, \
.module_name = KBUILD_MODNAME, \
.version = _version, \
}; \
static const struct module_version_attribute \
__used __attribute__ ((__section__ ("__modver"))) \
* __moduleparam_const __modver_attr = &___modver_attr
#endif
/* Optional firmware file (or files) needed by the module
* format is simply firmware file name. Multiple firmware
* files require multiple MODULE_FIRMWARE() specifiers */
#define MODULE_FIRMWARE(_firmware) MODULE_INFO(firmware, _firmware)
/* Given an address, look for it in the exception tables */
const struct exception_table_entry *search_exception_tables(unsigned long add);
struct notifier_block;
#ifdef CONFIG_MODULES
extern int modules_disabled; /* for sysctl */
/* Get/put a kernel symbol (calls must be symmetric) */
void *__symbol_get(const char *symbol);
void *__symbol_get_gpl(const char *symbol);
#define symbol_get(x) ((typeof(&x))(__symbol_get(VMLINUX_SYMBOL_STR(x))))
/* modules using other modules: kdb wants to see this. */
struct module_use {
struct list_head source_list;
struct list_head target_list;
struct module *source, *target;
};
enum module_state {
MODULE_STATE_LIVE, /* Normal state. */
MODULE_STATE_COMING, /* Full formed, running module_init. */
MODULE_STATE_GOING, /* Going away. */
MODULE_STATE_UNFORMED, /* Still setting it up. */
};
struct module;
struct mod_tree_node {
struct module *mod;
struct latch_tree_node node;
};
struct module {
enum module_state state;
/* Member of list of modules */
struct list_head list;
/* Unique handle for this module */
char name[MODULE_NAME_LEN];
/* Sysfs stuff. */
struct module_kobject mkobj;
struct module_attribute *modinfo_attrs;
const char *version;
const char *srcversion;
struct kobject *holders_dir;
/* Exported symbols */
const struct kernel_symbol *syms;
const unsigned long *crcs;
unsigned int num_syms;
/* Kernel parameters. */
struct mutex param_lock;
struct kernel_param *kp;
unsigned int num_kp;
/* GPL-only exported symbols. */
unsigned int num_gpl_syms;
const struct kernel_symbol *gpl_syms;
const unsigned long *gpl_crcs;
#ifdef CONFIG_UNUSED_SYMBOLS
/* unused exported symbols. */
const struct kernel_symbol *unused_syms;
const unsigned long *unused_crcs;
unsigned int num_unused_syms;
/* GPL-only, unused exported symbols. */
unsigned int num_unused_gpl_syms;
const struct kernel_symbol *unused_gpl_syms;
const unsigned long *unused_gpl_crcs;
#endif
#ifdef CONFIG_MODULE_SIG
/* Signature was verified. */
bool sig_ok;
#endif
/* symbols that will be GPL-only in the near future. */
const struct kernel_symbol *gpl_future_syms;
const unsigned long *gpl_future_crcs;
unsigned int num_gpl_future_syms;
/* Exception table */
unsigned int num_exentries;
struct exception_table_entry *extable;
/* Startup function. */
int (*init)(void);
/*
* If this is non-NULL, vfree() after init() returns.
*
* Cacheline align here, such that:
* module_init, module_core, init_size, core_size,
* init_text_size, core_text_size and mtn_core::{mod,node[0]}
* are on the same cacheline.
*/
void *module_init ____cacheline_aligned;
/* Here is the actual code + data, vfree'd on unload. */
void *module_core;
/* Here are the sizes of the init and core sections */
unsigned int init_size, core_size;
/* The size of the executable code in each section. */
unsigned int init_text_size, core_text_size;
#ifdef CONFIG_MODULES_TREE_LOOKUP
/*
* We want mtn_core::{mod,node[0]} to be in the same cacheline as the
* above entries such that a regular lookup will only touch one
* cacheline.
*/
struct mod_tree_node mtn_core;
struct mod_tree_node mtn_init;
#endif
/* Size of RO sections of the module (text+rodata) */
unsigned int init_ro_size, core_ro_size;
/* Arch-specific module values */
struct mod_arch_specific arch;
unsigned int taints; /* same bits as kernel:tainted */
#ifdef CONFIG_GENERIC_BUG
/* Support for BUG */
unsigned num_bugs;
struct list_head bug_list;
struct bug_entry *bug_table;
#endif
#ifdef CONFIG_KALLSYMS
/*
* We keep the symbol and string tables for kallsyms.
* The core_* fields below are temporary, loader-only (they
* could really be discarded after module init).
*/
Elf_Sym *symtab, *core_symtab;
unsigned int num_symtab, core_num_syms;
char *strtab, *core_strtab;
/* Section attributes */
struct module_sect_attrs *sect_attrs;
/* Notes attributes */
struct module_notes_attrs *notes_attrs;
#endif
/* The command line arguments (may be mangled). People like
keeping pointers to this stuff */
char *args;
#ifdef CONFIG_SMP
/* Per-cpu data. */
void __percpu *percpu;
unsigned int percpu_size;
#endif
#ifdef CONFIG_TRACEPOINTS
unsigned int num_tracepoints;
struct tracepoint * const *tracepoints_ptrs;
#endif
#ifdef HAVE_JUMP_LABEL
struct jump_entry *jump_entries;
unsigned int num_jump_entries;
#endif
#ifdef CONFIG_TRACING
unsigned int num_trace_bprintk_fmt;
const char **trace_bprintk_fmt_start;
#endif
#ifdef CONFIG_EVENT_TRACING
struct ftrace_event_call **trace_events;
unsigned int num_trace_events;
struct trace_enum_map **trace_enums;
unsigned int num_trace_enums;
#endif
#ifdef CONFIG_FTRACE_MCOUNT_RECORD
unsigned int num_ftrace_callsites;
unsigned long *ftrace_callsites;
#endif
#ifdef CONFIG_LIVEPATCH
bool klp_alive;
#endif
#ifdef CONFIG_MODULE_UNLOAD
/* What modules depend on me? */
struct list_head source_list;
/* What modules do I depend on? */
struct list_head target_list;
/* Destruction function. */
void (*exit)(void);
atomic_t refcnt;
#endif
#ifdef CONFIG_CONSTRUCTORS
/* Constructor functions. */
ctor_fn_t *ctors;
unsigned int num_ctors;
#endif
} ____cacheline_aligned;
#ifndef MODULE_ARCH_INIT
#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.*/
static inline int module_is_live(struct module *mod)
{
return mod->state != MODULE_STATE_GOING;
}
struct module *__module_text_address(unsigned long addr);
struct module *__module_address(unsigned long addr);
bool is_module_address(unsigned long addr);
bool is_module_percpu_address(unsigned long addr);
bool is_module_text_address(unsigned long addr);
static inline bool within_module_core(unsigned long addr,
const struct module *mod)
{
return (unsigned long)mod->module_core <= addr &&
addr < (unsigned long)mod->module_core + mod->core_size;
}
static inline bool within_module_init(unsigned long addr,
const struct module *mod)
{
return (unsigned long)mod->module_init <= addr &&
addr < (unsigned long)mod->module_init + mod->init_size;
}
static inline bool within_module(unsigned long addr, const struct module *mod)
{
return within_module_init(addr, mod) || within_module_core(addr, mod);
}
/* 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.
*
* Must be called with module_mutex held or preemption disabled.
*/
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
*
* Must be called with module_mutex held or preemption disabled.
*/
bool each_symbol_section(bool (*fn)(const struct symsearch *arr,
struct module *owner,
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,
char *name, char *module_name, int *exported);
/* 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)
#ifdef CONFIG_MODULE_UNLOAD
int module_refcount(struct module *mod);
void __symbol_put(const char *symbol);
#define symbol_put(x) __symbol_put(VMLINUX_SYMBOL_STR(x))
void symbol_put_addr(void *addr);
/* Sometimes we know we already have a refcount, and it's easier not
to handle the error case (which only happens with rmmod --wait). */
extern void __module_get(struct module *module);
/* This is the Right Way to get a module: if it fails, it's being removed,
* so pretend it's not there. */
extern bool try_module_get(struct module *module);
extern void module_put(struct module *module);
#else /*!CONFIG_MODULE_UNLOAD*/
static inline int try_module_get(struct module *module)
{
return !module || module_is_live(module);
}
static inline void module_put(struct module *module)
{
}
static inline void __module_get(struct module *module)
{
}
#define symbol_put(x) do { } while (0)
#define symbol_put_addr(p) do { } while (0)
#endif /* CONFIG_MODULE_UNLOAD */
int ref_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) \
({ \
struct module *__mod = (mod); \
__mod ? __mod->name : "kernel"; \
})
/* For kallsyms to ask for address resolution. namebuf should be at
* least KSYM_NAME_LEN long: a pointer to namebuf is returned if
* found, otherwise NULL. */
const char *module_address_lookup(unsigned long addr,
unsigned long *symbolsize,
unsigned long *offset,
char **modname,
char *namebuf);
int lookup_module_symbol_name(unsigned long addr, char *symname);
int lookup_module_symbol_attrs(unsigned long addr, unsigned long *size, unsigned long *offset, char *modname, char *name);
/* For extable.c to search modules' exception tables. */
const struct exception_table_entry *search_module_extables(unsigned long addr);
int register_module_notifier(struct notifier_block *nb);
int unregister_module_notifier(struct notifier_block *nb);
extern void print_modules(void);
#else /* !CONFIG_MODULES... */
/* Given an address, look for it in the exception tables. */
static inline const struct exception_table_entry *
search_module_extables(unsigned long addr)
{
return NULL;
}
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 bool is_module_address(unsigned long addr)
{
return false;
}
static inline bool is_module_percpu_address(unsigned long addr)
{
return false;
}
static inline bool is_module_text_address(unsigned long addr)
{
return false;
}
/* Get/put a kernel symbol (calls should be symmetric) */
#define symbol_get(x) ({ extern typeof(x) x __attribute__((weak)); &(x); })
#define symbol_put(x) do { } while (0)
#define symbol_put_addr(x) do { } while (0)
static inline void __module_get(struct module *module)
{
}
static inline int try_module_get(struct module *module)
{
return 1;
}
static inline void module_put(struct module *module)
{
}
#define module_name(mod) "kernel"
/* For kallsyms to ask for address resolution. NULL means not found. */
static inline const char *module_address_lookup(unsigned long addr,
unsigned long *symbolsize,
unsigned long *offset,
char **modname,
char *namebuf)
{
return NULL;
}
static inline int lookup_module_symbol_name(unsigned long addr, char *symname)
{
return -ERANGE;
}
static inline int lookup_module_symbol_attrs(unsigned long addr, unsigned long *size, unsigned long *offset, char *modname, char *name)
{
return -ERANGE;
}
static inline int module_get_kallsym(unsigned int symnum, unsigned long *value,
char *type, char *name,
char *module_name, int *exported)
{
return -ERANGE;
}
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 */
return 0;
}
static inline int unregister_module_notifier(struct notifier_block *nb)
{
return 0;
}
#define module_put_and_exit(code) do_exit(code)
static inline void print_modules(void)
{
}
#endif /* CONFIG_MODULES */
#ifdef CONFIG_SYSFS
extern struct kset *module_kset;
extern struct kobj_type module_ktype;
extern int module_sysfs_initialized;
#endif /* CONFIG_SYSFS */
#define symbol_request(x) try_then_request_module(symbol_get(x), "symbol:" #x)
/* BELOW HERE ALL THESE ARE OBSOLETE AND WILL VANISH */
#define __MODULE_STRING(x) __stringify(x)
#ifdef CONFIG_DEBUG_SET_MODULE_RONX
extern void set_all_modules_text_rw(void);
extern void set_all_modules_text_ro(void);
#else
static inline void set_all_modules_text_rw(void) { }
static inline void set_all_modules_text_ro(void) { }
#endif
#ifdef CONFIG_GENERIC_BUG
void module_bug_finalize(const Elf_Ehdr *, const Elf_Shdr *,
struct module *);
void module_bug_cleanup(struct module *);
#else /* !CONFIG_GENERIC_BUG */
static inline void module_bug_finalize(const Elf_Ehdr *hdr,
const Elf_Shdr *sechdrs,
struct module *mod)
{
}
static inline void module_bug_cleanup(struct module *mod) {}
#endif /* CONFIG_GENERIC_BUG */
#endif /* _LINUX_MODULE_H */