b3438f8266
This is a quick hack to overcome the fact that SRCU currently does not
allow static initializers, and we need to sometimes initialize those
things before any other initializers (even "core" ones) can do so.
Currently we don't allow this at all for modules, and the only user that
needs is right now is cpufreq. As reported by Thomas Gleixner:
"Commit b4dfdbb3c7 ("[PATCH] cpufreq:
make the transition_notifier chain use SRCU breaks cpu frequency
notification users, which register the callback > on core_init
level."
Cc: Thomas Gleixner <tglx@timesys.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Andrew Morton <akpm@osdl.org>,
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
298 lines
9.2 KiB
C
298 lines
9.2 KiB
C
#ifndef _LINUX_INIT_H
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#define _LINUX_INIT_H
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#include <linux/compiler.h>
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/* These macros are used to mark some functions or
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* initialized data (doesn't apply to uninitialized data)
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* as `initialization' functions. The kernel can take this
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* as hint that the function is used only during the initialization
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* phase and free up used memory resources after
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*
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* Usage:
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* For functions:
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*
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* You should add __init immediately before the function name, like:
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*
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* static void __init initme(int x, int y)
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* {
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* extern int z; z = x * y;
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* }
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*
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* If the function has a prototype somewhere, you can also add
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* __init between closing brace of the prototype and semicolon:
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*
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* extern int initialize_foobar_device(int, int, int) __init;
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*
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* For initialized data:
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* You should insert __initdata between the variable name and equal
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* sign followed by value, e.g.:
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*
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* static int init_variable __initdata = 0;
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* static char linux_logo[] __initdata = { 0x32, 0x36, ... };
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*
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* Don't forget to initialize data not at file scope, i.e. within a function,
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* as gcc otherwise puts the data into the bss section and not into the init
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* section.
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*
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* Also note, that this data cannot be "const".
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*/
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/* These are for everybody (although not all archs will actually
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discard it in modules) */
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#define __init __attribute__ ((__section__ (".init.text")))
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#define __initdata __attribute__ ((__section__ (".init.data")))
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#define __exitdata __attribute__ ((__section__(".exit.data")))
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#define __exit_call __attribute_used__ __attribute__ ((__section__ (".exitcall.exit")))
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#ifdef MODULE
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#define __exit __attribute__ ((__section__(".exit.text")))
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#else
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#define __exit __attribute_used__ __attribute__ ((__section__(".exit.text")))
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#endif
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/* For assembly routines */
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#define __INIT .section ".init.text","ax"
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#define __FINIT .previous
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#define __INITDATA .section ".init.data","aw"
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#ifndef __ASSEMBLY__
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/*
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* Used for initialization calls..
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*/
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typedef int (*initcall_t)(void);
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typedef void (*exitcall_t)(void);
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extern initcall_t __con_initcall_start[], __con_initcall_end[];
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extern initcall_t __security_initcall_start[], __security_initcall_end[];
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/* Defined in init/main.c */
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extern char saved_command_line[];
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extern unsigned int reset_devices;
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/* used by init/main.c */
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extern void setup_arch(char **);
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#endif
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#ifndef MODULE
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#ifndef __ASSEMBLY__
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/* initcalls are now grouped by functionality into separate
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* subsections. Ordering inside the subsections is determined
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* by link order.
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* For backwards compatibility, initcall() puts the call in
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* the device init subsection.
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*
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* The `id' arg to __define_initcall() is needed so that multiple initcalls
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* can point at the same handler without causing duplicate-symbol build errors.
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*/
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#define __define_initcall(level,fn,id) \
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static initcall_t __initcall_##fn##id __attribute_used__ \
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__attribute__((__section__(".initcall" level ".init"))) = fn
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/*
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* A "pure" initcall has no dependencies on anything else, and purely
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* initializes variables that couldn't be statically initialized.
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*
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* This only exists for built-in code, not for modules.
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*/
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#define pure_initcall(fn) __define_initcall("0",fn,1)
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#define core_initcall(fn) __define_initcall("1",fn,1)
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#define core_initcall_sync(fn) __define_initcall("1s",fn,1s)
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#define postcore_initcall(fn) __define_initcall("2",fn,2)
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#define postcore_initcall_sync(fn) __define_initcall("2s",fn,2s)
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#define arch_initcall(fn) __define_initcall("3",fn,3)
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#define arch_initcall_sync(fn) __define_initcall("3s",fn,3s)
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#define subsys_initcall(fn) __define_initcall("4",fn,4)
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#define subsys_initcall_sync(fn) __define_initcall("4s",fn,4s)
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#define fs_initcall(fn) __define_initcall("5",fn,5)
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#define fs_initcall_sync(fn) __define_initcall("5s",fn,5s)
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#define device_initcall(fn) __define_initcall("6",fn,6)
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#define device_initcall_sync(fn) __define_initcall("6s",fn,6s)
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#define late_initcall(fn) __define_initcall("7",fn,7)
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#define late_initcall_sync(fn) __define_initcall("7s",fn,7s)
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#define __initcall(fn) device_initcall(fn)
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#define __exitcall(fn) \
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static exitcall_t __exitcall_##fn __exit_call = fn
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#define console_initcall(fn) \
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static initcall_t __initcall_##fn \
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__attribute_used__ __attribute__((__section__(".con_initcall.init")))=fn
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#define security_initcall(fn) \
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static initcall_t __initcall_##fn \
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__attribute_used__ __attribute__((__section__(".security_initcall.init"))) = fn
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struct obs_kernel_param {
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const char *str;
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int (*setup_func)(char *);
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int early;
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};
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/*
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* Only for really core code. See moduleparam.h for the normal way.
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*
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* Force the alignment so the compiler doesn't space elements of the
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* obs_kernel_param "array" too far apart in .init.setup.
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*/
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#define __setup_param(str, unique_id, fn, early) \
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static char __setup_str_##unique_id[] __initdata = str; \
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static struct obs_kernel_param __setup_##unique_id \
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__attribute_used__ \
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__attribute__((__section__(".init.setup"))) \
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__attribute__((aligned((sizeof(long))))) \
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= { __setup_str_##unique_id, fn, early }
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#define __setup_null_param(str, unique_id) \
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__setup_param(str, unique_id, NULL, 0)
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#define __setup(str, fn) \
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__setup_param(str, fn, fn, 0)
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#define __obsolete_setup(str) \
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__setup_null_param(str, __LINE__)
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/* NOTE: fn is as per module_param, not __setup! Emits warning if fn
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* returns non-zero. */
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#define early_param(str, fn) \
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__setup_param(str, fn, fn, 1)
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/* Relies on saved_command_line being set */
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void __init parse_early_param(void);
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#endif /* __ASSEMBLY__ */
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/**
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* module_init() - driver initialization entry point
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* @x: function to be run at kernel boot time or module insertion
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*
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* module_init() will either be called during do_initcalls (if
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* builtin) or at module insertion time (if a module). There can only
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* be one per module.
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*/
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#define module_init(x) __initcall(x);
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/**
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* module_exit() - driver exit entry point
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* @x: function to be run when driver is removed
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*
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* module_exit() will wrap the driver clean-up code
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* with cleanup_module() when used with rmmod when
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* the driver is a module. If the driver is statically
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* compiled into the kernel, module_exit() has no effect.
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* There can only be one per module.
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*/
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#define module_exit(x) __exitcall(x);
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#else /* MODULE */
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/* Don't use these in modules, but some people do... */
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#define core_initcall(fn) module_init(fn)
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#define postcore_initcall(fn) module_init(fn)
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#define arch_initcall(fn) module_init(fn)
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#define subsys_initcall(fn) module_init(fn)
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#define fs_initcall(fn) module_init(fn)
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#define device_initcall(fn) module_init(fn)
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#define late_initcall(fn) module_init(fn)
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#define security_initcall(fn) module_init(fn)
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/* These macros create a dummy inline: gcc 2.9x does not count alias
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as usage, hence the `unused function' warning when __init functions
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are declared static. We use the dummy __*_module_inline functions
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both to kill the warning and check the type of the init/cleanup
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function. */
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/* Each module must use one module_init(), or one no_module_init */
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#define module_init(initfn) \
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static inline initcall_t __inittest(void) \
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{ return initfn; } \
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int init_module(void) __attribute__((alias(#initfn)));
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/* This is only required if you want to be unloadable. */
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#define module_exit(exitfn) \
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static inline exitcall_t __exittest(void) \
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{ return exitfn; } \
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void cleanup_module(void) __attribute__((alias(#exitfn)));
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#define __setup_param(str, unique_id, fn) /* nothing */
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#define __setup_null_param(str, unique_id) /* nothing */
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#define __setup(str, func) /* nothing */
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#define __obsolete_setup(str) /* nothing */
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#endif
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/* Data marked not to be saved by software_suspend() */
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#define __nosavedata __attribute__ ((__section__ (".data.nosave")))
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/* This means "can be init if no module support, otherwise module load
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may call it." */
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#ifdef CONFIG_MODULES
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#define __init_or_module
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#define __initdata_or_module
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#else
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#define __init_or_module __init
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#define __initdata_or_module __initdata
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#endif /*CONFIG_MODULES*/
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#ifdef CONFIG_HOTPLUG
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#define __devinit
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#define __devinitdata
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#define __devexit
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#define __devexitdata
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#else
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#define __devinit __init
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#define __devinitdata __initdata
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#define __devexit __exit
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#define __devexitdata __exitdata
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#endif
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#ifdef CONFIG_HOTPLUG_CPU
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#define __cpuinit
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#define __cpuinitdata
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#define __cpuexit
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#define __cpuexitdata
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#else
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#define __cpuinit __init
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#define __cpuinitdata __initdata
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#define __cpuexit __exit
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#define __cpuexitdata __exitdata
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#endif
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#if defined(CONFIG_MEMORY_HOTPLUG) || defined(CONFIG_ACPI_HOTPLUG_MEMORY) \
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|| defined(CONFIG_ACPI_HOTPLUG_MEMORY_MODULE)
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#define __meminit
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#define __meminitdata
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#define __memexit
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#define __memexitdata
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#else
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#define __meminit __init
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#define __meminitdata __initdata
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#define __memexit __exit
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#define __memexitdata __exitdata
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#endif
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/* Functions marked as __devexit may be discarded at kernel link time, depending
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on config options. Newer versions of binutils detect references from
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retained sections to discarded sections and flag an error. Pointers to
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__devexit functions must use __devexit_p(function_name), the wrapper will
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insert either the function_name or NULL, depending on the config options.
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*/
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#if defined(MODULE) || defined(CONFIG_HOTPLUG)
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#define __devexit_p(x) x
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#else
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#define __devexit_p(x) NULL
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#endif
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#ifdef MODULE
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#define __exit_p(x) x
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#else
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#define __exit_p(x) NULL
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#endif
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#endif /* _LINUX_INIT_H */
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