blob: d82b4b2e1d25d69839ccd92292c2d9ae5d4736ed [file] [log] [blame]
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_INIT_H
#define _LINUX_INIT_H
#include <linux/compiler.h>
#include <linux/types.h>
/* Built-in __init functions needn't be compiled with retpoline */
#if defined(__noretpoline) && !defined(MODULE)
#define __noinitretpoline __noretpoline
#define __noinitretpoline
/* 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 __latent_entropy __noinitretpoline __nocfi
#define __initdata __section("")
#define __initconst __section(".init.rodata")
#define __exitdata __section("")
#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. 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("")
#define __refconst __section(".ref.rodata")
#ifdef MODULE
#define __exitused
#define __exitused __used
#define __exit __section(".exit.text") __exitused __cold notrace
/* Used for MEMORY_HOTPLUG */
#define __meminit __section(".meminit.text") __cold notrace \
#define __meminitdata __section("")
#define __meminitconst __section(".meminit.rodata")
#define __memexit __section(".memexit.text") __exitused __cold notrace
#define __memexitdata __section("")
#define __memexitconst __section(".memexit.rodata")
/* For assembly routines */
#define __HEAD .section ".head.text","ax"
#define __INIT .section ".init.text","ax"
#define __FINIT .previous
#define __INITDATA .section "","aw",%progbits
#define __INITRODATA .section ".init.rodata","a",%progbits
#define __FINITDATA .previous
#define __MEMINIT .section ".meminit.text", "ax"
#define __MEMINITDATA .section "", "aw"
#define __MEMINITRODATA .section ".meminit.rodata", "a"
/* silence warnings when references are OK */
#define __REF .section ".ref.text", "ax"
#define __REFDATA .section "", "aw"
#define __REFCONST .section ".ref.rodata", "a"
#ifndef __ASSEMBLY__
* Used for initialization calls..
typedef int (*initcall_t)(void);
typedef void (*exitcall_t)(void);
typedef int initcall_entry_t;
static inline initcall_t initcall_from_entry(initcall_entry_t *entry)
return offset_to_ptr(entry);
typedef initcall_t initcall_entry_t;
static inline initcall_t initcall_from_entry(initcall_entry_t *entry)
return *entry;
extern initcall_entry_t __con_initcall_start[], __con_initcall_end[];
/* Used for contructor calls. */
typedef void (*ctor_fn_t)(void);
struct file_system_type;
/* 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 init_rootfs(void);
extern struct file_system_type rootfs_fs_type;
extern bool rodata_enabled;
void mark_rodata_ro(void);
extern void (*late_time_init)(void);
extern bool initcall_debug;
#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.
* Initcalls are run by placing pointers in initcall sections that the
* kernel iterates at runtime. The linker can do dead code / data elimination
* and remove that completely, so the initcall sections have to be marked
* as KEEP() in the linker script.
/* Format: <modname>__<counter>_<line>_<fn> */
#define __initcall_id(fn) \
__PASTE(__, \
__PASTE(_, \
__PASTE(__LINE__, \
__PASTE(_, fn))))))
/* Format: __<prefix>__<iid><id> */
#define __initcall_name(prefix, __iid, id) \
__PASTE(__, \
__PASTE(prefix, \
__PASTE(__, \
__PASTE(__iid, id))))
* With LTO, the compiler doesn't necessarily obey link order for
* initcalls. In order to preserve the correct order, we add each
* variable into its own section and generate a linker script (in
* scripts/ to specify the order of the sections.
#define __initcall_section(__sec, __iid) \
#__sec ".init.." #__iid
* With LTO, the compiler can rename static functions to avoid
* global naming collisions. We use a global stub function for
* initcalls to create a stable symbol name whose address can be
* taken in inline assembly when PREL32 relocations are used.
#define __initcall_stub(fn, __iid, id) \
__initcall_name(initstub, __iid, id)
#define __define_initcall_stub(__stub, fn) \
int __init __cficanonical __stub(void); \
int __init __cficanonical __stub(void) \
{ \
return fn(); \
} \
#define __initcall_section(__sec, __iid) \
#__sec ".init"
#define __initcall_stub(fn, __iid, id) fn
#define __define_initcall_stub(__stub, fn) \
#define ____define_initcall(fn, __stub, __name, __sec) \
__define_initcall_stub(__stub, fn) \
asm(".section \"" __sec "\", \"a\" \n" \
__stringify(__name) ": \n" \
".long " __stringify(__stub) " - . \n" \
".previous \n"); \
static_assert(__same_type(initcall_t, &fn));
#define ____define_initcall(fn, __unused, __name, __sec) \
static initcall_t __name __used \
__attribute__((__section__(__sec))) = fn;
#define __unique_initcall(fn, id, __sec, __iid) \
____define_initcall(fn, \
__initcall_stub(fn, __iid, id), \
__initcall_name(initcall, __iid, id), \
__initcall_section(__sec, __iid))
#define ___define_initcall(fn, id, __sec) \
__unique_initcall(fn, id, __sec, __initcall_id(fn))
#define __define_initcall(fn, id) ___define_initcall(fn, id, .initcall##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) ___define_initcall(fn, con, .con_initcall)
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") \
__aligned(__alignof__(struct obs_kernel_param)) \
= { __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; \
} \
early_param(str_on, parse_##var##_on); \
static int __init parse_##var##_off(char *arg) \
{ \
var = 0; \
return 0; \
} \
early_param(str_off, parse_##var##_off)
/* Relies on boot_command_line being set */
void __init parse_early_param(void);
void __init parse_early_options(char *cmdline);
#endif /* __ASSEMBLY__ */
#else /* MODULE */
#define __setup_param(str, unique_id, fn) /* nothing */
#define __setup(str, func) /* nothing */
/* Data marked not to be saved by software suspend */
#define __nosavedata __section(".data..nosave")
#ifdef MODULE
#define __exit_p(x) x
#define __exit_p(x) NULL
#endif /* _LINUX_INIT_H */