[linux-2.6-block.git] / include / linux / init.h

#ifndef _LINUX_INIT_H
#define _LINUX_INIT_H

#include <linux/compiler.h>

/* These macros are used to mark some functions or 
 * initialized data (doesn't apply to uninitialized data)
 * as `initialization' functions. The kernel can take this
 * as hint that the function is used only during the initialization
 * phase and free up used memory resources after
 *
 * Usage:
 * For functions:
 * 
 * You should add __init immediately before the function name, like:
 *
 * static void __init initme(int x, int y)
 * {
 *    extern int z; z = x * y;
 * }
 *
 * If the function has a prototype somewhere, you can also add
 * __init between closing brace of the prototype and semicolon:
 *
 * extern int initialize_foobar_device(int, int, int) __init;
 *
 * For initialized data:
 * You should insert __initdata between the variable name and equal
 * sign followed by value, e.g.:
 *
 * static int init_variable __initdata = 0;
 * static char linux_logo[] __initdata = { 0x32, 0x36, ... };
 *
 * Don't forget to initialize data not at file scope, i.e. within a function,
 * as gcc otherwise puts the data into the bss section and not into the init
 * section.
 * 
 * Also note, that this data cannot be "const".
 */

/* These are for everybody (although not all archs will actually
   discard it in modules) */
#define __init		__section(.init.text) __cold
#define __initdata	__section(.init.data)
#define __exitdata	__section(.exit.data)
#define __exit_call	__used __section(.exitcall.exit)

/* modpost check for section mismatches during the kernel build.
 * A section mismatch happens when there are references from a
 * code or data section to an init section (both code or data).
 * The init sections are (for most archs) discarded by the kernel
 * when early init has completed so all such references are potential bugs.
 * For exit sections the same issue exists.
 * The following markers are used for the cases where the reference to
 * the *init / *exit section (code or data) is valid and will teach
 * modpost not to issue a warning.
 * The markers follow same syntax rules as __init / __initdata. */
#define __ref            __section(.ref.text) noinline
#define __refdata        __section(.ref.data)
#define __refconst       __section(.ref.rodata)

/* backward compatibility note
 *  A few places hardcode the old section names:
 *  .text.init.refok
 *  .data.init.refok
 *  .exit.text.refok
 *  They should be converted to use the defines from this file
 */

/* compatibility defines */
#define __init_refok     __ref
#define __initdata_refok __refdata
#define __exit_refok     __ref


#ifdef MODULE
#define __exitused
#else
#define __exitused  __used
#endif

#define __exit          __section(.exit.text) __exitused __cold

/* Used for HOTPLUG */
#define __devinit        __section(.devinit.text) __cold
#define __devinitdata    __section(.devinit.data)
#define __devinitconst   __section(.devinit.rodata)
#define __devexit        __section(.devexit.text) __exitused __cold
#define __devexitdata    __section(.devexit.data)
#define __devexitconst   __section(.devexit.rodata)

/* Used for HOTPLUG_CPU */
#define __cpuinit        __section(.cpuinit.text) __cold
#define __cpuinitdata    __section(.cpuinit.data)
#define __cpuinitconst   __section(.cpuinit.rodata)
#define __cpuexit        __section(.cpuexit.text) __exitused __cold
#define __cpuexitdata    __section(.cpuexit.data)
#define __cpuexitconst   __section(.cpuexit.rodata)

/* Used for MEMORY_HOTPLUG */
#define __meminit        __section(.meminit.text) __cold
#define __meminitdata    __section(.meminit.data)
#define __meminitconst   __section(.meminit.rodata)
#define __memexit        __section(.memexit.text) __exitused __cold
#define __memexitdata    __section(.memexit.data)
#define __memexitconst   __section(.memexit.rodata)

/* For assembly routines */
#define __INIT		.section	".init.text","ax"
#define __FINIT		.previous

#define __INITDATA	.section	".init.data","aw"
#define __FINITDATA	.previous

#define __DEVINIT        .section	".devinit.text", "ax"
#define __DEVINITDATA    .section	".devinit.data", "aw"

#define __CPUINIT        .section	".cpuinit.text", "ax"
#define __CPUINITDATA    .section	".cpuinit.data", "aw"

#define __MEMINIT        .section	".meminit.text", "ax"
#define __MEMINITDATA    .section	".meminit.data", "aw"

/* silence warnings when references are OK */
#define __REF            .section       ".ref.text", "ax"
#define __REFDATA        .section       ".ref.data", "aw"
#define __REFCONST       .section       ".ref.rodata", "aw"

#ifndef __ASSEMBLY__
/*
 * Used for initialization calls..
 */
typedef int (*initcall_t)(void);
typedef void (*exitcall_t)(void);

extern initcall_t __con_initcall_start[], __con_initcall_end[];
extern initcall_t __security_initcall_start[], __security_initcall_end[];

/* Defined in init/main.c */
extern char __initdata boot_command_line[];
extern char *saved_command_line;
extern unsigned int reset_devices;

/* used by init/main.c */
void setup_arch(char **);
void prepare_namespace(void);

#endif
  
#ifndef MODULE

#ifndef __ASSEMBLY__

/* initcalls are now grouped by functionality into separate 
 * subsections. Ordering inside the subsections is determined
 * by link order. 
 * For backwards compatibility, initcall() puts the call in 
 * the device init subsection.
 *
 * The `id' arg to __define_initcall() is needed so that multiple initcalls
 * can point at the same handler without causing duplicate-symbol build errors.
 */

#define __define_initcall(level,fn,id) \
	static initcall_t __initcall_##fn##id __used \
	__attribute__((__section__(".initcall" level ".init"))) = fn

/*
 * A "pure" initcall has no dependencies on anything else, and purely
 * initializes variables that couldn't be statically initialized.
 *
 * This only exists for built-in code, not for modules.
 */
#define pure_initcall(fn)		__define_initcall("0",fn,0)

#define core_initcall(fn)		__define_initcall("1",fn,1)
#define core_initcall_sync(fn)		__define_initcall("1s",fn,1s)
#define postcore_initcall(fn)		__define_initcall("2",fn,2)
#define postcore_initcall_sync(fn)	__define_initcall("2s",fn,2s)
#define arch_initcall(fn)		__define_initcall("3",fn,3)
#define arch_initcall_sync(fn)		__define_initcall("3s",fn,3s)
#define subsys_initcall(fn)		__define_initcall("4",fn,4)
#define subsys_initcall_sync(fn)	__define_initcall("4s",fn,4s)
#define fs_initcall(fn)			__define_initcall("5",fn,5)
#define fs_initcall_sync(fn)		__define_initcall("5s",fn,5s)
#define rootfs_initcall(fn)		__define_initcall("rootfs",fn,rootfs)
#define device_initcall(fn)		__define_initcall("6",fn,6)
#define device_initcall_sync(fn)	__define_initcall("6s",fn,6s)
#define late_initcall(fn)		__define_initcall("7",fn,7)
#define late_initcall_sync(fn)		__define_initcall("7s",fn,7s)

#define __initcall(fn) device_initcall(fn)

#define __exitcall(fn) \
	static exitcall_t __exitcall_##fn __exit_call = fn

#define console_initcall(fn) \
	static initcall_t __initcall_##fn \
	__used __section(.con_initcall.init) = fn

#define security_initcall(fn) \
	static initcall_t __initcall_##fn \
	__used __section(.security_initcall.init) = fn

struct obs_kernel_param {
	const char *str;
	int (*setup_func)(char *);
	int early;
};

/*
 * Only for really core code.  See moduleparam.h for the normal way.
 *
 * Force the alignment so the compiler doesn't space elements of the
 * obs_kernel_param "array" too far apart in .init.setup.
 */
#define __setup_param(str, unique_id, fn, early)			\
	static char __setup_str_##unique_id[] __initdata __aligned(1) = str; \
	static struct obs_kernel_param __setup_##unique_id	\
		__used __section(.init.setup)			\
		__attribute__((aligned((sizeof(long)))))	\
		= { __setup_str_##unique_id, fn, early }

#define __setup_null_param(str, unique_id)			\
	__setup_param(str, unique_id, NULL, 0)

#define __setup(str, fn)					\
	__setup_param(str, fn, fn, 0)

/* NOTE: fn is as per module_param, not __setup!  Emits warning if fn
 * returns non-zero. */
#define early_param(str, fn)					\
	__setup_param(str, fn, fn, 1)

/* Relies on boot_command_line being set */
void __init parse_early_param(void);
#endif /* __ASSEMBLY__ */

/**
 * module_init() - driver initialization entry point
 * @x: function to be run at kernel boot time or module insertion
 * 
 * module_init() will either be called during do_initcalls() (if
 * builtin) or at module insertion time (if a module).  There can only
 * be one per module.
 */
#define module_init(x)	__initcall(x);

/**
 * module_exit() - driver exit entry point
 * @x: function to be run when driver is removed
 * 
 * module_exit() will wrap the driver clean-up code
 * with cleanup_module() when used with rmmod when
 * the driver is a module.  If the driver is statically
 * compiled into the kernel, module_exit() has no effect.
 * There can only be one per module.
 */
#define module_exit(x)	__exitcall(x);

#else /* MODULE */

/* Don't use these in modules, but some people do... */
#define core_initcall(fn)		module_init(fn)
#define postcore_initcall(fn)		module_init(fn)
#define arch_initcall(fn)		module_init(fn)
#define subsys_initcall(fn)		module_init(fn)
#define fs_initcall(fn)			module_init(fn)
#define device_initcall(fn)		module_init(fn)
#define late_initcall(fn)		module_init(fn)

#define security_initcall(fn)		module_init(fn)

/* These macros create a dummy inline: gcc 2.9x does not count alias
 as usage, hence the `unused function' warning when __init functions
 are declared static. We use the dummy __*_module_inline functions
 both to kill the warning and check the type of the init/cleanup
 function. */

/* Each module must use one module_init(), or one no_module_init */
#define module_init(initfn)					\
	static inline initcall_t __inittest(void)		\
	{ return initfn; }					\
	int init_module(void) __attribute__((alias(#initfn)));

/* This is only required if you want to be unloadable. */
#define module_exit(exitfn)					\
	static inline exitcall_t __exittest(void)		\
	{ return exitfn; }					\
	void cleanup_module(void) __attribute__((alias(#exitfn)));

#define __setup_param(str, unique_id, fn)	/* nothing */
#define __setup_null_param(str, unique_id) 	/* nothing */
#define __setup(str, func) 			/* nothing */
#endif

/* Data marked not to be saved by software suspend */
#define __nosavedata __section(.data.nosave)

/* This means "can be init if no module support, otherwise module load
   may call it." */
#ifdef CONFIG_MODULES
#define __init_or_module
#define __initdata_or_module
#else
#define __init_or_module __init
#define __initdata_or_module __initdata
#endif /*CONFIG_MODULES*/

/* Functions marked as __devexit may be discarded at kernel link time, depending
   on config options.  Newer versions of binutils detect references from
   retained sections to discarded sections and flag an error.  Pointers to
   __devexit functions must use __devexit_p(function_name), the wrapper will
   insert either the function_name or NULL, depending on the config options.
 */
#if defined(MODULE) || defined(CONFIG_HOTPLUG)
#define __devexit_p(x) x
#else
#define __devexit_p(x) NULL
#endif

#ifdef MODULE
#define __exit_p(x) x
#else
#define __exit_p(x) NULL
#endif

#endif /* _LINUX_INIT_H */
Commit	Line	Data
1da177e4 LT	1	#ifndef _LINUX_INIT_H
	2	#define _LINUX_INIT_H
	3
1da177e4 LT	4	#include <linux/compiler.h>
	5
	6	/* These macros are used to mark some functions or
	7	* initialized data (doesn't apply to uninitialized data)
	8	* as `initialization' functions. The kernel can take this
	9	* as hint that the function is used only during the initialization
	10	* phase and free up used memory resources after
	11	*
	12	* Usage:
	13	* For functions:
	14	*
	15	* You should add __init immediately before the function name, like:
	16	*
	17	* static void __init initme(int x, int y)
	18	* {
	19	* extern int z; z = x * y;
	20	* }
	21	*
	22	* If the function has a prototype somewhere, you can also add
	23	* __init between closing brace of the prototype and semicolon:
	24	*
	25	* extern int initialize_foobar_device(int, int, int) __init;
	26	*
	27	* For initialized data:
	28	* You should insert __initdata between the variable name and equal
	29	* sign followed by value, e.g.:
	30	*
	31	* static int init_variable __initdata = 0;
	32	* static char linux_logo[] __initdata = { 0x32, 0x36, ... };
	33	*
	34	* Don't forget to initialize data not at file scope, i.e. within a function,
	35	* as gcc otherwise puts the data into the bss section and not into the init
	36	* section.
	37	*
	38	* Also note, that this data cannot be "const".
	39	*/
	40
	41	/* These are for everybody (although not all archs will actually
	42	discard it in modules) */
f3fe866d SR	43	#define __init __section(.init.text) __cold
	44	#define __initdata __section(.init.data)
	45	#define __exitdata __section(.exit.data)
3ff6eecc	46	#define __exit_call __used __section(.exitcall.exit)
1da177e4	47
0e0d314e SR	48	/* modpost check for section mismatches during the kernel build.
	49	* A section mismatch happens when there are references from a
	50	* code or data section to an init section (both code or data).
	51	* The init sections are (for most archs) discarded by the kernel
	52	* when early init has completed so all such references are potential bugs.
	53	* For exit sections the same issue exists.
	54	* The following markers are used for the cases where the reference to
312b1485 SR	55	* the init / exit section (code or data) is valid and will teach
312b1485 SR	56	* modpost not to issue a warning.
0e0d314e	57	* The markers follow same syntax rules as __init / __initdata. */
312b1485 SR	58	#define __ref __section(.ref.text) noinline
	59	#define __refdata __section(.ref.data)
	60	#define __refconst __section(.ref.rodata)
	61
	62	/* backward compatibility note
	63	* A few places hardcode the old section names:
	64	* .text.init.refok
	65	* .data.init.refok
	66	* .exit.text.refok
	67	* They should be converted to use the defines from this file
	68	*/
	69
	70	/* compatibility defines */
	71	#define __init_refok __ref
	72	#define __initdata_refok __refdata
	73	#define __exit_refok __ref
	74
0e0d314e	75
1da177e4	76	#ifdef MODULE
eb8f6890	77	#define __exitused
1da177e4	78	#else
eb8f6890	79	#define __exitused __used
1da177e4 LT	80	#endif
1da177e4 LT	81
eb8f6890 SR	82	#define __exit __section(.exit.text) __exitused __cold
	83
	84	/* Used for HOTPLUG */
	85	#define __devinit __section(.devinit.text) __cold
	86	#define __devinitdata __section(.devinit.data)
	87	#define __devinitconst __section(.devinit.rodata)
	88	#define __devexit __section(.devexit.text) __exitused __cold
	89	#define __devexitdata __section(.devexit.data)
	90	#define __devexitconst __section(.devexit.rodata)
	91
	92	/* Used for HOTPLUG_CPU */
	93	#define __cpuinit __section(.cpuinit.text) __cold
	94	#define __cpuinitdata __section(.cpuinit.data)
	95	#define __cpuinitconst __section(.cpuinit.rodata)
	96	#define __cpuexit __section(.cpuexit.text) __exitused __cold
	97	#define __cpuexitdata __section(.cpuexit.data)
	98	#define __cpuexitconst __section(.cpuexit.rodata)
	99
	100	/* Used for MEMORY_HOTPLUG */
	101	#define __meminit __section(.meminit.text) __cold
	102	#define __meminitdata __section(.meminit.data)
	103	#define __meminitconst __section(.meminit.rodata)
	104	#define __memexit __section(.memexit.text) __exitused __cold
	105	#define __memexitdata __section(.memexit.data)
	106	#define __memexitconst __section(.memexit.rodata)
	107
1da177e4 LT	108	/* For assembly routines */
1da177e4 LT	109	#define __INIT .section ".init.text","ax"
86c0baf1	110	#define __FINIT .previous
eb8f6890	111
838c4118	112	#define __INITDATA .section ".init.data","aw"
9f9975a5	113	#define __FINITDATA .previous
1da177e4	114
eb8f6890 SR	115	#define __DEVINIT .section ".devinit.text", "ax"
	116	#define __DEVINITDATA .section ".devinit.data", "aw"
	117
	118	#define __CPUINIT .section ".cpuinit.text", "ax"
	119	#define __CPUINITDATA .section ".cpuinit.data", "aw"
	120
	121	#define __MEMINIT .section ".meminit.text", "ax"
	122	#define __MEMINITDATA .section ".meminit.data", "aw"
	123
312b1485 SR	124	/* silence warnings when references are OK */
	125	#define __REF .section ".ref.text", "ax"
	126	#define __REFDATA .section ".ref.data", "aw"
	127	#define __REFCONST .section ".ref.rodata", "aw"
312b1485	128
1da177e4 LT	129	#ifndef __ASSEMBLY__
	130	/*
	131	* Used for initialization calls..
	132	*/
	133	typedef int (*initcall_t)(void);
	134	typedef void (*exitcall_t)(void);
	135
	136	extern initcall_t __con_initcall_start[], __con_initcall_end[];
	137	extern initcall_t __security_initcall_start[], __security_initcall_end[];
	138
	139	/* Defined in init/main.c */
30d7e0d4 ABL	140	extern char __initdata boot_command_line[];
30d7e0d4 ABL	141	extern char *saved_command_line;
7e96287d	142	extern unsigned int reset_devices;
77d47582 AB	143
77d47582 AB	144	/* used by init/main.c */
46595390 AB	145	void setup_arch(char **);
46595390 AB	146	void prepare_namespace(void);
77d47582	147
1da177e4 LT	148	#endif
	149
	150	#ifndef MODULE
	151
	152	#ifndef __ASSEMBLY__
	153
	154	/* initcalls are now grouped by functionality into separate
	155	* subsections. Ordering inside the subsections is determined
	156	* by link order.
	157	* For backwards compatibility, initcall() puts the call in
	158	* the device init subsection.
735a7ffb AM	159	*
	160	* The `id' arg to __define_initcall() is needed so that multiple initcalls
	161	* can point at the same handler without causing duplicate-symbol build errors.
1da177e4 LT	162	*/
1da177e4 LT	163
735a7ffb	164	#define __define_initcall(level,fn,id) \
3ff6eecc	165	static initcall_t __initcall_##fn##id __used \
1da177e4 LT	166	__attribute__((__section__(".initcall" level ".init"))) = fn
1da177e4 LT	167
b3438f82 LT	168	/*
	169	* A "pure" initcall has no dependencies on anything else, and purely
	170	* initializes variables that couldn't be statically initialized.
	171	*
	172	* This only exists for built-in code, not for modules.
	173	*/
73dd1166	174	#define pure_initcall(fn) __define_initcall("0",fn,0)
b3438f82	175
735a7ffb AM	176	#define core_initcall(fn) __define_initcall("1",fn,1)
	177	#define core_initcall_sync(fn) __define_initcall("1s",fn,1s)
	178	#define postcore_initcall(fn) __define_initcall("2",fn,2)
	179	#define postcore_initcall_sync(fn) __define_initcall("2s",fn,2s)
	180	#define arch_initcall(fn) __define_initcall("3",fn,3)
	181	#define arch_initcall_sync(fn) __define_initcall("3s",fn,3s)
	182	#define subsys_initcall(fn) __define_initcall("4",fn,4)
	183	#define subsys_initcall_sync(fn) __define_initcall("4s",fn,4s)
	184	#define fs_initcall(fn) __define_initcall("5",fn,5)
	185	#define fs_initcall_sync(fn) __define_initcall("5s",fn,5s)
8d610dd5	186	#define rootfs_initcall(fn) __define_initcall("rootfs",fn,rootfs)
735a7ffb AM	187	#define device_initcall(fn) __define_initcall("6",fn,6)
	188	#define device_initcall_sync(fn) __define_initcall("6s",fn,6s)
	189	#define late_initcall(fn) __define_initcall("7",fn,7)
	190	#define late_initcall_sync(fn) __define_initcall("7s",fn,7s)
1da177e4 LT	191
	192	#define __initcall(fn) device_initcall(fn)
	193
	194	#define __exitcall(fn) \
	195	static exitcall_t __exitcall_##fn __exit_call = fn
	196
	197	#define console_initcall(fn) \
	198	static initcall_t __initcall_##fn \
3ff6eecc	199	__used __section(.con_initcall.init) = fn
1da177e4 LT	200
	201	#define security_initcall(fn) \
	202	static initcall_t __initcall_##fn \
3ff6eecc	203	__used __section(.security_initcall.init) = fn
1da177e4 LT	204
	205	struct obs_kernel_param {
	206	const char *str;
	207	int (setup_func)(char );
	208	int early;
	209	};
	210
	211	/*
	212	* Only for really core code. See moduleparam.h for the normal way.
	213	*
	214	* Force the alignment so the compiler doesn't space elements of the
	215	* obs_kernel_param "array" too far apart in .init.setup.
	216	*/
	217	#define __setup_param(str, unique_id, fn, early) \
d5aa0daf	218	static char __setup_str_##unique_id[] __initdata __aligned(1) = str; \
1da177e4	219	static struct obs_kernel_param __setup_##unique_id \
3ff6eecc	220	__used __section(.init.setup) \
1da177e4 LT	221	__attribute__((aligned((sizeof(long))))) \
	222	= { __setup_str_##unique_id, fn, early }
	223
	224	#define __setup_null_param(str, unique_id) \
	225	__setup_param(str, unique_id, NULL, 0)
	226
	227	#define __setup(str, fn) \
	228	__setup_param(str, fn, fn, 0)
	229
1da177e4 LT	230	/* NOTE: fn is as per module_param, not __setup! Emits warning if fn
	231	* returns non-zero. */
	232	#define early_param(str, fn) \
	233	__setup_param(str, fn, fn, 1)
	234
30d7e0d4	235	/* Relies on boot_command_line being set */
1da177e4 LT	236	void __init parse_early_param(void);
	237	#endif /* __ASSEMBLY__ */
	238
	239	/**
	240	* module_init() - driver initialization entry point
	241	* @x: function to be run at kernel boot time or module insertion
	242	*
72fd4a35	243	* module_init() will either be called during do_initcalls() (if
1da177e4 LT	244	* builtin) or at module insertion time (if a module). There can only
	245	* be one per module.
	246	*/
	247	#define module_init(x) __initcall(x);
	248
	249	/**
	250	* module_exit() - driver exit entry point
	251	* @x: function to be run when driver is removed
	252	*
	253	* module_exit() will wrap the driver clean-up code
	254	* with cleanup_module() when used with rmmod when
	255	* the driver is a module. If the driver is statically
	256	* compiled into the kernel, module_exit() has no effect.
	257	* There can only be one per module.
	258	*/
	259	#define module_exit(x) __exitcall(x);
	260
	261	#else /* MODULE */
	262
	263	/* Don't use these in modules, but some people do... */
	264	#define core_initcall(fn) module_init(fn)
	265	#define postcore_initcall(fn) module_init(fn)
	266	#define arch_initcall(fn) module_init(fn)
	267	#define subsys_initcall(fn) module_init(fn)
	268	#define fs_initcall(fn) module_init(fn)
	269	#define device_initcall(fn) module_init(fn)
	270	#define late_initcall(fn) module_init(fn)
	271
	272	#define security_initcall(fn) module_init(fn)
	273
	274	/* These macros create a dummy inline: gcc 2.9x does not count alias
	275	as usage, hence the `unused function' warning when __init functions
	276	are declared static. We use the dummy __*_module_inline functions
	277	both to kill the warning and check the type of the init/cleanup
	278	function. */
	279
	280	/* Each module must use one module_init(), or one no_module_init */
	281	#define module_init(initfn) \
	282	static inline initcall_t __inittest(void) \
	283	{ return initfn; } \
	284	int init_module(void) __attribute__((alias(#initfn)));
	285
	286	/* This is only required if you want to be unloadable. */
	287	#define module_exit(exitfn) \
	288	static inline exitcall_t __exittest(void) \
	289	{ return exitfn; } \
	290	void cleanup_module(void) __attribute__((alias(#exitfn)));
	291
	292	#define __setup_param(str, unique_id, fn) /* nothing */
	293	#define __setup_null_param(str, unique_id) /* nothing */
	294	#define __setup(str, func) /* nothing */
1da177e4 LT	295	#endif
1da177e4 LT	296
ab3bfca7	297	/* Data marked not to be saved by software suspend */
f3fe866d	298	#define __nosavedata __section(.data.nosave)
1da177e4 LT	299
	300	/* This means "can be init if no module support, otherwise module load
	301	may call it." */
	302	#ifdef CONFIG_MODULES
	303	#define __init_or_module
	304	#define __initdata_or_module
	305	#else
	306	#define __init_or_module __init
	307	#define __initdata_or_module __initdata
	308	#endif /CONFIG_MODULES/
	309
1da177e4 LT	310	/* Functions marked as __devexit may be discarded at kernel link time, depending
	311	on config options. Newer versions of binutils detect references from
	312	retained sections to discarded sections and flag an error. Pointers to
	313	__devexit functions must use __devexit_p(function_name), the wrapper will
	314	insert either the function_name or NULL, depending on the config options.
	315	*/
	316	#if defined(MODULE) \|\| defined(CONFIG_HOTPLUG)
	317	#define __devexit_p(x) x
	318	#else
	319	#define __devexit_p(x) NULL
	320	#endif
	321
	322	#ifdef MODULE
	323	#define __exit_p(x) x
	324	#else
	325	#define __exit_p(x) NULL
	326	#endif
	327
	328	#endif /* _LINUX_INIT_H */