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Diffstat (limited to 'include/linux/init.h')
| -rw-r--r-- | include/linux/init.h | 378 |
1 files changed, 378 insertions, 0 deletions
diff --git a/include/linux/init.h b/include/linux/init.h new file mode 100644 index 000000000..077d7f93b --- /dev/null +++ b/include/linux/init.h @@ -0,0 +1,378 @@ +/* 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 +#else +#define __noinitretpoline +#endif + +/* 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 +#define __initdata __section(".init.data") +#define __initconst __section(".init.rodata") +#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. 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 __section(".ref.rodata") + +#ifdef MODULE +#define __exitused +#else +#define __exitused __used +#endif + +#define __exit __section(".exit.text") __exitused __cold notrace + +/* Used for MEMORY_HOTPLUG */ +#define __meminit __section(".meminit.text") __cold notrace \ + __latent_entropy +#define __meminitdata __section(".meminit.data") +#define __meminitconst __section(".meminit.rodata") +#define __memexit __section(".memexit.text") __exitused __cold notrace +#define __memexitdata __section(".memexit.data") +#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 ".init.data","aw",%progbits +#define __INITRODATA .section ".init.rodata","a",%progbits +#define __FINITDATA .previous + +#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); + +#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS +typedef int initcall_entry_t; + +static inline initcall_t initcall_from_entry(initcall_entry_t *entry) +{ + return offset_to_ptr(entry); +} +#else +typedef initcall_t initcall_entry_t; + +static inline initcall_t initcall_from_entry(initcall_entry_t *entry) +{ + return *entry; +} +#endif + +extern initcall_entry_t __con_initcall_start[], __con_initcall_end[]; + +/* Used for constructor 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; + +#if defined(CONFIG_STRICT_KERNEL_RWX) || defined(CONFIG_STRICT_MODULE_RWX) +extern bool rodata_enabled; +#endif +#ifdef CONFIG_STRICT_KERNEL_RWX +void mark_rodata_ro(void); +#endif + +extern void (*late_time_init)(void); + +extern bool initcall_debug; + +#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. + * + * 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(__KBUILD_MODNAME, \ + __PASTE(__, \ + __PASTE(__COUNTER__, \ + __PASTE(_, \ + __PASTE(__LINE__, \ + __PASTE(_, fn)))))) + +/* Format: __<prefix>__<iid><id> */ +#define __initcall_name(prefix, __iid, id) \ + __PASTE(__, \ + __PASTE(prefix, \ + __PASTE(__, \ + __PASTE(__iid, id)))) + +#ifdef CONFIG_LTO_CLANG +/* + * 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/link-vmlinux.sh) 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 __stub(void); \ + int __init __stub(void) \ + { \ + return fn(); \ + } \ + __ADDRESSABLE(__stub) +#else +#define __initcall_section(__sec, __iid) \ + #__sec ".init" + +#define __initcall_stub(fn, __iid, id) fn + +#define __define_initcall_stub(__stub, fn) \ + __ADDRESSABLE(fn) +#endif + +#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS +#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)); +#else +#define ____define_initcall(fn, __unused, __name, __sec) \ + static initcall_t __name __used \ + __attribute__((__section__(__sec))) = fn; +#endif + +#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 } + +/* + * NOTE: __setup functions return values: + * @fn returns 1 (or non-zero) if the option argument is "handled" + * and returns 0 if the option argument is "not handled". + */ +#define __setup(str, fn) \ + __setup_param(str, fn, fn, 0) + +/* + * NOTE: @fn is as per module_param, not __setup! + * I.e., @fn returns 0 for no error or non-zero for error + * (possibly @fn returns a -errno value, but it does not matter). + * 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 */ +#endif + +/* Data marked not to be saved by software suspend */ +#define __nosavedata __section(".data..nosave") + +#ifdef MODULE +#define __exit_p(x) x +#else +#define __exit_p(x) NULL +#endif + +#endif /* _LINUX_INIT_H */ |