/* SPDX-License-Identifier: GPL-2.0 */ #ifndef _LINUX_INIT_H #define _LINUX_INIT_H #include <linux/build_bug.h> #include <linux/compiler.h> #include <linux/stringify.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 saved_command_line_len; extern unsigned int reset_devices; /* used by init/main.c */ void setup_arch(char **); void prepare_namespace(void); void __init init_rootfs(void); void init_IRQ(void); void time_init(void); void poking_init(void); void pgtable_cache_init(void); extern initcall_entry_t __initcall_start[]; extern initcall_entry_t __initcall0_start[]; extern initcall_entry_t __initcall1_start[]; extern initcall_entry_t __initcall2_start[]; extern initcall_entry_t __initcall3_start[]; extern initcall_entry_t __initcall4_start[]; extern initcall_entry_t __initcall5_start[]; extern initcall_entry_t __initcall6_start[]; extern initcall_entry_t __initcall7_start[]; extern initcall_entry_t __initcall_end[]; 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; }; extern const struct obs_kernel_param __setup_start[], __setup_end[]; /* * 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 */