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Diffstat (limited to 'kernel/include/linux/init.h')
| -rw-r--r-- | kernel/include/linux/init.h | 389 |
1 files changed, 389 insertions, 0 deletions
diff --git a/kernel/include/linux/init.h b/kernel/include/linux/init.h new file mode 100644 index 000000000..21b6d768e --- /dev/null +++ b/kernel/include/linux/init.h @@ -0,0 +1,389 @@ +#ifndef _LINUX_INIT_H +#define _LINUX_INIT_H + +#include <linux/compiler.h> +#include <linux/types.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 or __initconst between the variable name + * and equal sign followed by value, e.g.: + * + * static int init_variable __initdata = 0; + * static const char linux_logo[] __initconst = { 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. + */ + +/* These are for everybody (although not all archs will actually + discard it in modules) */ +#define __init __section(.init.text) __cold notrace +#define __initdata __section(.init.data) +#define __initconst __constsection(.init.rodata) +#define __exitdata __section(.exit.data) +#define __exit_call __used __section(.exitcall.exit) + +/* + * Some architecture have tool chains which do not handle rodata attributes + * correctly. For those disable special sections for const, so that other + * architectures can annotate correctly. + */ +#ifdef CONFIG_BROKEN_RODATA +#define __constsection(x) +#else +#define __constsection(x) __section(x) +#endif + +/* + * 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. Intended semantics is that a code or + * data tagged __ref* can reference code or data from init section without + * producing a warning (of course, no warning does not mean code is + * correct, so optimally document why the __ref is needed and why it's OK). + * + * The markers follow same syntax rules as __init / __initdata. + */ +#define __ref __section(.ref.text) noinline +#define __refdata __section(.ref.data) +#define __refconst __constsection(.ref.rodata) + +/* 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 notrace + +/* temporary, until all users are removed */ +#define __cpuinit +#define __cpuinitdata +#define __cpuinitconst +#define __cpuexit +#define __cpuexitdata +#define __cpuexitconst + +/* Used for MEMORY_HOTPLUG */ +#define __meminit __section(.meminit.text) __cold notrace +#define __meminitdata __section(.meminit.data) +#define __meminitconst __constsection(.meminit.rodata) +#define __memexit __section(.memexit.text) __exitused __cold notrace +#define __memexitdata __section(.memexit.data) +#define __memexitconst __constsection(.memexit.rodata) + +/* For assembly routines */ +#define __HEAD .section ".head.text","ax" +#define __INIT .section ".init.text","ax" +#define __FINIT .previous + +#define __INITDATA .section ".init.data","aw",%progbits +#define __INITRODATA .section ".init.rodata","a",%progbits +#define __FINITDATA .previous + +/* temporary, until all users are removed */ +#define __CPUINIT + +#define __MEMINIT .section ".meminit.text", "ax" +#define __MEMINITDATA .section ".meminit.data", "aw" +#define __MEMINITRODATA .section ".meminit.rodata", "a" + +/* silence warnings when references are OK */ +#define __REF .section ".ref.text", "ax" +#define __REFDATA .section ".ref.data", "aw" +#define __REFCONST .section ".ref.rodata", "a" + +#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[]; + +/* Used for contructor calls. */ +typedef void (*ctor_fn_t)(void); + +/* Defined in init/main.c */ +extern int do_one_initcall(initcall_t fn); +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); +void __init load_default_modules(void); +int __init init_rootfs(void); + +extern void (*late_time_init)(void); + +extern bool initcall_debug; + +#endif + +#ifndef MODULE + +#ifndef __ASSEMBLY__ + +#ifdef CONFIG_LTO +/* Work around a LTO gcc problem: when there is no reference to a variable + * in a module it will be moved to the end of the program. This causes + * reordering of initcalls which the kernel does not like. + * Add a dummy reference function to avoid this. The function is + * deleted by the linker. + */ +#define LTO_REFERENCE_INITCALL(x) \ + ; /* yes this is needed */ \ + static __used __exit void *reference_##x(void) \ + { \ + return &x; \ + } +#else +#define LTO_REFERENCE_INITCALL(x) +#endif + +/* 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(fn, id) \ + static initcall_t __initcall_##fn##id __used \ + __attribute__((__section__(".initcall" #id ".init"))) = fn; \ + LTO_REFERENCE_INITCALL(__initcall_##fn##id) + +/* + * Early initcalls run before initializing SMP. + * + * Only for built-in code, not modules. + */ +#define early_initcall(fn) __define_initcall(fn, early) + +/* + * 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. + * Keep main.c:initcall_level_names[] in sync. + */ +#define pure_initcall(fn) __define_initcall(fn, 0) + +#define core_initcall(fn) __define_initcall(fn, 1) +#define core_initcall_sync(fn) __define_initcall(fn, 1s) +#define postcore_initcall(fn) __define_initcall(fn, 2) +#define postcore_initcall_sync(fn) __define_initcall(fn, 2s) +#define arch_initcall(fn) __define_initcall(fn, 3) +#define arch_initcall_sync(fn) __define_initcall(fn, 3s) +#define subsys_initcall(fn) __define_initcall(fn, 4) +#define subsys_initcall_sync(fn) __define_initcall(fn, 4s) +#define fs_initcall(fn) __define_initcall(fn, 5) +#define fs_initcall_sync(fn) __define_initcall(fn, 5s) +#define rootfs_initcall(fn) __define_initcall(fn, rootfs) +#define device_initcall(fn) __define_initcall(fn, 6) +#define device_initcall_sync(fn) __define_initcall(fn, 6s) +#define late_initcall(fn) __define_initcall(fn, 7) +#define late_initcall_sync(fn) __define_initcall(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 const char __setup_str_##unique_id[] __initconst \ + __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(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) + +#define early_param_on_off(str_on, str_off, var, config) \ + \ + int var = IS_ENABLED(config); \ + \ + static int __init parse_##var##_on(char *arg) \ + { \ + var = 1; \ + return 0; \ + } \ + __setup_param(str_on, parse_##var##_on, parse_##var##_on, 1); \ + \ + static int __init parse_##var##_off(char *arg) \ + { \ + var = 0; \ + return 0; \ + } \ + __setup_param(str_off, parse_##var##_off, parse_##var##_off, 1) + +/* Relies on boot_command_line being set */ +void __init parse_early_param(void); +void __init parse_early_options(char *cmdline); +#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 */ + +/* + * In most cases loadable modules do not need custom + * initcall levels. There are still some valid cases where + * a driver may be needed early if built in, and does not + * matter when built as a loadable module. Like bus + * snooping debug drivers. + */ +#define early_initcall(fn) module_init(fn) +#define core_initcall(fn) module_init(fn) +#define core_initcall_sync(fn) module_init(fn) +#define postcore_initcall(fn) module_init(fn) +#define postcore_initcall_sync(fn) module_init(fn) +#define arch_initcall(fn) module_init(fn) +#define subsys_initcall(fn) module_init(fn) +#define subsys_initcall_sync(fn) module_init(fn) +#define fs_initcall(fn) module_init(fn) +#define fs_initcall_sync(fn) module_init(fn) +#define rootfs_initcall(fn) module_init(fn) +#define device_initcall(fn) module_init(fn) +#define device_initcall_sync(fn) module_init(fn) +#define late_initcall(fn) module_init(fn) +#define late_initcall_sync(fn) module_init(fn) + +#define console_initcall(fn) module_init(fn) +#define security_initcall(fn) module_init(fn) + +/* Each module must use one 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(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 +#define __initconst_or_module +#define __INIT_OR_MODULE .text +#define __INITDATA_OR_MODULE .data +#define __INITRODATA_OR_MODULE .section ".rodata","a",%progbits +#else +#define __init_or_module __init +#define __initdata_or_module __initdata +#define __initconst_or_module __initconst +#define __INIT_OR_MODULE __INIT +#define __INITDATA_OR_MODULE __INITDATA +#define __INITRODATA_OR_MODULE __INITRODATA +#endif /*CONFIG_MODULES*/ + +#ifdef MODULE +#define __exit_p(x) x +#else +#define __exit_p(x) NULL +#endif + +#endif /* _LINUX_INIT_H */ |