382 lines
12 KiB
C
382 lines
12 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _LINUX_INIT_H
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#define _LINUX_INIT_H
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#include <linux/build_bug.h>
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#include <linux/compiler.h>
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#include <linux/stringify.h>
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#include <linux/types.h>
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/* Built-in __init functions needn't be compiled with retpoline */
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#if defined(__noretpoline) && !defined(MODULE)
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#define __noinitretpoline __noretpoline
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#else
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#define __noinitretpoline
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#endif
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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 or __initconst between the variable name
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* and equal 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 const char linux_logo[] __initconst = { 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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/* These are for everybody (although not all archs will actually
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discard it in modules) */
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#define __init __section(".init.text") __cold __latent_entropy __noinitretpoline
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#define __initdata __section(".init.data")
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#define __initconst __section(".init.rodata")
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#define __exitdata __section(".exit.data")
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#define __exit_call __used __section(".exitcall.exit")
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/*
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* modpost check for section mismatches during the kernel build.
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* A section mismatch happens when there are references from a
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* code or data section to an init section (both code or data).
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* The init sections are (for most archs) discarded by the kernel
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* when early init has completed so all such references are potential bugs.
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* For exit sections the same issue exists.
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*
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* The following markers are used for the cases where the reference to
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* the *init / *exit section (code or data) is valid and will teach
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* modpost not to issue a warning. Intended semantics is that a code or
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* data tagged __ref* can reference code or data from init section without
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* producing a warning (of course, no warning does not mean code is
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* correct, so optimally document why the __ref is needed and why it's OK).
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*
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* The markers follow same syntax rules as __init / __initdata.
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*/
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#define __ref __section(".ref.text") noinline
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#define __refdata __section(".ref.data")
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#define __refconst __section(".ref.rodata")
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#ifdef MODULE
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#define __exitused
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#else
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#define __exitused __used
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#endif
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#define __exit __section(".exit.text") __exitused __cold notrace
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/* Used for MEMORY_HOTPLUG */
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#define __meminit __section(".meminit.text") __cold notrace \
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__latent_entropy
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#define __meminitdata __section(".meminit.data")
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#define __meminitconst __section(".meminit.rodata")
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#define __memexit __section(".memexit.text") __exitused __cold notrace
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#define __memexitdata __section(".memexit.data")
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#define __memexitconst __section(".memexit.rodata")
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/* For assembly routines */
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#define __HEAD .section ".head.text","ax"
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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",%progbits
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#define __INITRODATA .section ".init.rodata","a",%progbits
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#define __FINITDATA .previous
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#define __MEMINIT .section ".meminit.text", "ax"
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#define __MEMINITDATA .section ".meminit.data", "aw"
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#define __MEMINITRODATA .section ".meminit.rodata", "a"
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/* silence warnings when references are OK */
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#define __REF .section ".ref.text", "ax"
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#define __REFDATA .section ".ref.data", "aw"
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#define __REFCONST .section ".ref.rodata", "a"
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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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#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
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typedef int initcall_entry_t;
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static inline initcall_t initcall_from_entry(initcall_entry_t *entry)
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{
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return offset_to_ptr(entry);
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}
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#else
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typedef initcall_t initcall_entry_t;
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static inline initcall_t initcall_from_entry(initcall_entry_t *entry)
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{
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return *entry;
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}
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#endif
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extern initcall_entry_t __con_initcall_start[], __con_initcall_end[];
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/* Used for constructor calls. */
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typedef void (*ctor_fn_t)(void);
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struct file_system_type;
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/* Defined in init/main.c */
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extern int do_one_initcall(initcall_t fn);
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extern char __initdata boot_command_line[];
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extern char *saved_command_line;
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extern unsigned int saved_command_line_len;
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extern unsigned int reset_devices;
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/* used by init/main.c */
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void setup_arch(char **);
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void prepare_namespace(void);
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void __init init_rootfs(void);
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extern struct file_system_type rootfs_fs_type;
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#if defined(CONFIG_STRICT_KERNEL_RWX) || defined(CONFIG_STRICT_MODULE_RWX)
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extern bool rodata_enabled;
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#endif
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#ifdef CONFIG_STRICT_KERNEL_RWX
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void mark_rodata_ro(void);
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#endif
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extern void (*late_time_init)(void);
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extern bool initcall_debug;
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#endif
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#ifndef MODULE
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#ifndef __ASSEMBLY__
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/*
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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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* Initcalls are run by placing pointers in initcall sections that the
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* kernel iterates at runtime. The linker can do dead code / data elimination
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* and remove that completely, so the initcall sections have to be marked
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* as KEEP() in the linker script.
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*/
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/* Format: <modname>__<counter>_<line>_<fn> */
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#define __initcall_id(fn) \
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__PASTE(__KBUILD_MODNAME, \
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__PASTE(__, \
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__PASTE(__COUNTER__, \
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__PASTE(_, \
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__PASTE(__LINE__, \
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__PASTE(_, fn))))))
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/* Format: __<prefix>__<iid><id> */
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#define __initcall_name(prefix, __iid, id) \
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__PASTE(__, \
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__PASTE(prefix, \
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__PASTE(__, \
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__PASTE(__iid, id))))
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#ifdef CONFIG_LTO_CLANG
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/*
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* With LTO, the compiler doesn't necessarily obey link order for
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* initcalls. In order to preserve the correct order, we add each
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* variable into its own section and generate a linker script (in
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* scripts/link-vmlinux.sh) to specify the order of the sections.
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*/
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#define __initcall_section(__sec, __iid) \
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#__sec ".init.." #__iid
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/*
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* With LTO, the compiler can rename static functions to avoid
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* global naming collisions. We use a global stub function for
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* initcalls to create a stable symbol name whose address can be
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* taken in inline assembly when PREL32 relocations are used.
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*/
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#define __initcall_stub(fn, __iid, id) \
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__initcall_name(initstub, __iid, id)
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#define __define_initcall_stub(__stub, fn) \
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int __init __stub(void); \
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int __init __stub(void) \
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{ \
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return fn(); \
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} \
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__ADDRESSABLE(__stub)
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#else
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#define __initcall_section(__sec, __iid) \
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#__sec ".init"
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#define __initcall_stub(fn, __iid, id) fn
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#define __define_initcall_stub(__stub, fn) \
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__ADDRESSABLE(fn)
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#endif
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#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
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#define ____define_initcall(fn, __stub, __name, __sec) \
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__define_initcall_stub(__stub, fn) \
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asm(".section \"" __sec "\", \"a\" \n" \
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__stringify(__name) ": \n" \
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".long " __stringify(__stub) " - . \n" \
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".previous \n"); \
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static_assert(__same_type(initcall_t, &fn));
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#else
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#define ____define_initcall(fn, __unused, __name, __sec) \
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static initcall_t __name __used \
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__attribute__((__section__(__sec))) = fn;
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#endif
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#define __unique_initcall(fn, id, __sec, __iid) \
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____define_initcall(fn, \
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__initcall_stub(fn, __iid, id), \
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__initcall_name(initcall, __iid, id), \
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__initcall_section(__sec, __iid))
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#define ___define_initcall(fn, id, __sec) \
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__unique_initcall(fn, id, __sec, __initcall_id(fn))
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#define __define_initcall(fn, id) ___define_initcall(fn, id, .initcall##id)
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/*
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* Early initcalls run before initializing SMP.
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*
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* Only for built-in code, not modules.
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*/
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#define early_initcall(fn) __define_initcall(fn, early)
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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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* Keep main.c:initcall_level_names[] in sync.
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*/
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#define pure_initcall(fn) __define_initcall(fn, 0)
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#define core_initcall(fn) __define_initcall(fn, 1)
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#define core_initcall_sync(fn) __define_initcall(fn, 1s)
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#define postcore_initcall(fn) __define_initcall(fn, 2)
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#define postcore_initcall_sync(fn) __define_initcall(fn, 2s)
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#define arch_initcall(fn) __define_initcall(fn, 3)
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#define arch_initcall_sync(fn) __define_initcall(fn, 3s)
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#define subsys_initcall(fn) __define_initcall(fn, 4)
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#define subsys_initcall_sync(fn) __define_initcall(fn, 4s)
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#define fs_initcall(fn) __define_initcall(fn, 5)
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#define fs_initcall_sync(fn) __define_initcall(fn, 5s)
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#define rootfs_initcall(fn) __define_initcall(fn, rootfs)
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#define device_initcall(fn) __define_initcall(fn, 6)
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#define device_initcall_sync(fn) __define_initcall(fn, 6s)
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#define late_initcall(fn) __define_initcall(fn, 7)
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#define late_initcall_sync(fn) __define_initcall(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) ___define_initcall(fn, con, .con_initcall)
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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 const char __setup_str_##unique_id[] __initconst \
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__aligned(1) = str; \
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static struct obs_kernel_param __setup_##unique_id \
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__used __section(".init.setup") \
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__aligned(__alignof__(struct obs_kernel_param)) \
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= { __setup_str_##unique_id, fn, early }
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/*
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* NOTE: __setup functions return values:
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* @fn returns 1 (or non-zero) if the option argument is "handled"
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* and returns 0 if the option argument is "not handled".
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*/
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#define __setup(str, fn) \
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__setup_param(str, fn, fn, 0)
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/*
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* NOTE: @fn is as per module_param, not __setup!
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* I.e., @fn returns 0 for no error or non-zero for error
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* (possibly @fn returns a -errno value, but it does not matter).
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* Emits warning if @fn returns non-zero.
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*/
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#define early_param(str, fn) \
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__setup_param(str, fn, fn, 1)
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#define early_param_on_off(str_on, str_off, var, config) \
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\
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int var = IS_ENABLED(config); \
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\
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static int __init parse_##var##_on(char *arg) \
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{ \
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var = 1; \
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return 0; \
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} \
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early_param(str_on, parse_##var##_on); \
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\
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static int __init parse_##var##_off(char *arg) \
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{ \
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var = 0; \
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return 0; \
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} \
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early_param(str_off, parse_##var##_off)
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/* Relies on boot_command_line being set */
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void __init parse_early_param(void);
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void __init parse_early_options(char *cmdline);
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#endif /* __ASSEMBLY__ */
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#else /* MODULE */
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#define __setup_param(str, unique_id, fn) /* nothing */
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#define __setup(str, func) /* 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 __section(".data..nosave")
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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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