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22f0a27367
The __cpuinit type of throwaway sections might have made sense some time ago when RAM was more constrained, but now the savings do not offset the cost and complications. For example, the fix in commit5e427ec2d0("x86: Fix bit corruption at CPU resume time") is a good example of the nasty type of bugs that can be created with improper use of the various __init prefixes. After a discussion on LKML[1] it was decided that cpuinit should go the way of devinit and be phased out. Once all the users are gone, we can then finally remove the macros themselves from linux/init.h. As an interim step, we can dummy out the macros to be no-ops, and this will allow us to avoid a giant tree-wide patch, and instead we can feed in smaller chunks mainly via the arch/ trees. This is in keeping with commit78d86c213f("init.h: Remove __dev* sections from the kernel") We don't strictly need to dummy out the macros to do this, but if we don't then some harmless section mismatch warnings may temporarily result. For example, notify_cpu_starting() and cpu_up() are arch independent (kernel/cpu.c) and are flagged as __cpuinit. And hence the calling functions in the arch specific code are also expected to be __cpuinit -- if not, then we get the section mismatch warning. Two of the three __CPUINIT variants are not used whatsoever, and so they are simply removed directly at this point in time. [1] https://lkml.org/lkml/2013/5/20/589 Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
339 lines
11 KiB
C
339 lines
11 KiB
C
#ifndef _LINUX_INIT_H
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#define _LINUX_INIT_H
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#include <linux/compiler.h>
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#include <linux/types.h>
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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 between the variable name and equal
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* 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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* Also note, that this data cannot be "const".
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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 notrace
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#define __initdata __section(.init.data)
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#define __initconst __constsection(.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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* Some architecture have tool chains which do not handle rodata attributes
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* correctly. For those disable special sections for const, so that other
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* architectures can annotate correctly.
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*/
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#ifdef CONFIG_BROKEN_RODATA
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#define __constsection(x)
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#else
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#define __constsection(x) __section(x)
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#endif
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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 __constsection(.ref.rodata)
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/* compatibility defines */
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#define __init_refok __ref
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#define __initdata_refok __refdata
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#define __exit_refok __ref
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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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/* temporary, until all users are removed */
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#define __cpuinit
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#define __cpuinitdata
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#define __cpuinitconst
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#define __cpuexit
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#define __cpuexitdata
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#define __cpuexitconst
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/* Used for MEMORY_HOTPLUG */
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#define __meminit __section(.meminit.text) __cold notrace
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#define __meminitdata __section(.meminit.data)
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#define __meminitconst __constsection(.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 __constsection(.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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/* temporary, until all users are removed */
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#define __CPUINIT
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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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extern initcall_t __con_initcall_start[], __con_initcall_end[];
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extern initcall_t __security_initcall_start[], __security_initcall_end[];
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/* Used for contructor calls. */
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typedef void (*ctor_fn_t)(void);
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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 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 load_default_modules(void);
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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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/* 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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#define __define_initcall(fn, id) \
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static initcall_t __initcall_##fn##id __used \
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__attribute__((__section__(".initcall" #id ".init"))) = fn
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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) \
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static initcall_t __initcall_##fn \
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__used __section(.con_initcall.init) = fn
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#define security_initcall(fn) \
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static initcall_t __initcall_##fn \
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__used __section(.security_initcall.init) = fn
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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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__attribute__((aligned((sizeof(long))))) \
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= { __setup_str_##unique_id, fn, early }
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#define __setup(str, fn) \
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__setup_param(str, fn, fn, 0)
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/* NOTE: fn is as per module_param, not __setup! Emits warning if fn
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* returns non-zero. */
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#define early_param(str, fn) \
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__setup_param(str, fn, fn, 1)
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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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/**
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* module_init() - driver initialization entry point
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* @x: function to be run at kernel boot time or module insertion
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*
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* module_init() will either be called during do_initcalls() (if
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* builtin) or at module insertion time (if a module). There can only
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* be one per module.
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*/
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#define module_init(x) __initcall(x);
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/**
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* module_exit() - driver exit entry point
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* @x: function to be run when driver is removed
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*
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* module_exit() will wrap the driver clean-up code
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* with cleanup_module() when used with rmmod when
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* the driver is a module. If the driver is statically
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* compiled into the kernel, module_exit() has no effect.
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* There can only be one per module.
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*/
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#define module_exit(x) __exitcall(x);
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#else /* MODULE */
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/* Don't use these in loadable modules, but some people do... */
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#define early_initcall(fn) module_init(fn)
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#define core_initcall(fn) module_init(fn)
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#define postcore_initcall(fn) module_init(fn)
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#define arch_initcall(fn) module_init(fn)
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#define subsys_initcall(fn) module_init(fn)
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#define fs_initcall(fn) module_init(fn)
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#define device_initcall(fn) module_init(fn)
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#define late_initcall(fn) module_init(fn)
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#define security_initcall(fn) module_init(fn)
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/* Each module must use one module_init(). */
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#define module_init(initfn) \
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static inline initcall_t __inittest(void) \
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{ return initfn; } \
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int init_module(void) __attribute__((alias(#initfn)));
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/* This is only required if you want to be unloadable. */
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#define module_exit(exitfn) \
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static inline exitcall_t __exittest(void) \
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{ return exitfn; } \
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void cleanup_module(void) __attribute__((alias(#exitfn)));
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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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/* This means "can be init if no module support, otherwise module load
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may call it." */
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#ifdef CONFIG_MODULES
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#define __init_or_module
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#define __initdata_or_module
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#define __initconst_or_module
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#define __INIT_OR_MODULE .text
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#define __INITDATA_OR_MODULE .data
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#define __INITRODATA_OR_MODULE .section ".rodata","a",%progbits
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#else
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#define __init_or_module __init
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#define __initdata_or_module __initdata
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#define __initconst_or_module __initconst
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#define __INIT_OR_MODULE __INIT
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#define __INITDATA_OR_MODULE __INITDATA
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#define __INITRODATA_OR_MODULE __INITRODATA
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#endif /*CONFIG_MODULES*/
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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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