LCOV - code coverage report
Current view: top level - include/linux - init.h (source / functions) Hit Total Coverage
Test: landlock.info Lines: 2 2 100.0 %
Date: 2021-04-22 12:43:58 Functions: 0 0 -

          Line data    Source code
       1             : /* SPDX-License-Identifier: GPL-2.0 */
       2             : #ifndef _LINUX_INIT_H
       3             : #define _LINUX_INIT_H
       4             : 
       5             : #include <linux/compiler.h>
       6             : #include <linux/types.h>
       7             : 
       8             : /* Built-in __init functions needn't be compiled with retpoline */
       9             : #if defined(__noretpoline) && !defined(MODULE)
      10             : #define __noinitretpoline __noretpoline
      11             : #else
      12             : #define __noinitretpoline
      13             : #endif
      14             : 
      15             : /* These macros are used to mark some functions or 
      16             :  * initialized data (doesn't apply to uninitialized data)
      17             :  * as `initialization' functions. The kernel can take this
      18             :  * as hint that the function is used only during the initialization
      19             :  * phase and free up used memory resources after
      20             :  *
      21             :  * Usage:
      22             :  * For functions:
      23             :  * 
      24             :  * You should add __init immediately before the function name, like:
      25             :  *
      26             :  * static void __init initme(int x, int y)
      27             :  * {
      28             :  *    extern int z; z = x * y;
      29             :  * }
      30             :  *
      31             :  * If the function has a prototype somewhere, you can also add
      32             :  * __init between closing brace of the prototype and semicolon:
      33             :  *
      34             :  * extern int initialize_foobar_device(int, int, int) __init;
      35             :  *
      36             :  * For initialized data:
      37             :  * You should insert __initdata or __initconst between the variable name
      38             :  * and equal sign followed by value, e.g.:
      39             :  *
      40             :  * static int init_variable __initdata = 0;
      41             :  * static const char linux_logo[] __initconst = { 0x32, 0x36, ... };
      42             :  *
      43             :  * Don't forget to initialize data not at file scope, i.e. within a function,
      44             :  * as gcc otherwise puts the data into the bss section and not into the init
      45             :  * section.
      46             :  */
      47             : 
      48             : /* These are for everybody (although not all archs will actually
      49             :    discard it in modules) */
      50             : #define __init          __section(".init.text") __cold  __latent_entropy __noinitretpoline
      51             : #define __initdata      __section(".init.data")
      52             : #define __initconst     __section(".init.rodata")
      53             : #define __exitdata      __section(".exit.data")
      54             : #define __exit_call     __used __section(".exitcall.exit")
      55             : 
      56             : /*
      57             :  * modpost check for section mismatches during the kernel build.
      58             :  * A section mismatch happens when there are references from a
      59             :  * code or data section to an init section (both code or data).
      60             :  * The init sections are (for most archs) discarded by the kernel
      61             :  * when early init has completed so all such references are potential bugs.
      62             :  * For exit sections the same issue exists.
      63             :  *
      64             :  * The following markers are used for the cases where the reference to
      65             :  * the *init / *exit section (code or data) is valid and will teach
      66             :  * modpost not to issue a warning.  Intended semantics is that a code or
      67             :  * data tagged __ref* can reference code or data from init section without
      68             :  * producing a warning (of course, no warning does not mean code is
      69             :  * correct, so optimally document why the __ref is needed and why it's OK).
      70             :  *
      71             :  * The markers follow same syntax rules as __init / __initdata.
      72             :  */
      73             : #define __ref            __section(".ref.text") noinline
      74             : #define __refdata        __section(".ref.data")
      75             : #define __refconst       __section(".ref.rodata")
      76             : 
      77             : #ifdef MODULE
      78             : #define __exitused
      79             : #else
      80             : #define __exitused  __used
      81             : #endif
      82             : 
      83             : #define __exit          __section(".exit.text") __exitused __cold notrace
      84             : 
      85             : /* Used for MEMORY_HOTPLUG */
      86             : #define __meminit        __section(".meminit.text") __cold notrace \
      87             :                                                   __latent_entropy
      88             : #define __meminitdata    __section(".meminit.data")
      89             : #define __meminitconst   __section(".meminit.rodata")
      90             : #define __memexit        __section(".memexit.text") __exitused __cold notrace
      91             : #define __memexitdata    __section(".memexit.data")
      92             : #define __memexitconst   __section(".memexit.rodata")
      93             : 
      94             : /* For assembly routines */
      95             : #define __HEAD          .section        ".head.text","ax"
      96             : #define __INIT          .section        ".init.text","ax"
      97             : #define __FINIT         .previous
      98             : 
      99             : #define __INITDATA      .section        ".init.data","aw",%progbits
     100             : #define __INITRODATA    .section        ".init.rodata","a",%progbits
     101             : #define __FINITDATA     .previous
     102             : 
     103             : #define __MEMINIT        .section       ".meminit.text", "ax"
     104             : #define __MEMINITDATA    .section       ".meminit.data", "aw"
     105             : #define __MEMINITRODATA  .section       ".meminit.rodata", "a"
     106             : 
     107             : /* silence warnings when references are OK */
     108             : #define __REF            .section       ".ref.text", "ax"
     109             : #define __REFDATA        .section       ".ref.data", "aw"
     110             : #define __REFCONST       .section       ".ref.rodata", "a"
     111             : 
     112             : #ifndef __ASSEMBLY__
     113             : /*
     114             :  * Used for initialization calls..
     115             :  */
     116             : typedef int (*initcall_t)(void);
     117             : typedef void (*exitcall_t)(void);
     118             : 
     119             : #ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
     120             : typedef int initcall_entry_t;
     121             : 
     122         259 : static inline initcall_t initcall_from_entry(initcall_entry_t *entry)
     123             : {
     124         259 :         return offset_to_ptr(entry);
     125             : }
     126             : #else
     127             : typedef initcall_t initcall_entry_t;
     128             : 
     129             : static inline initcall_t initcall_from_entry(initcall_entry_t *entry)
     130             : {
     131             :         return *entry;
     132             : }
     133             : #endif
     134             : 
     135             : extern initcall_entry_t __con_initcall_start[], __con_initcall_end[];
     136             : 
     137             : /* Used for contructor calls. */
     138             : typedef void (*ctor_fn_t)(void);
     139             : 
     140             : struct file_system_type;
     141             : 
     142             : /* Defined in init/main.c */
     143             : extern int do_one_initcall(initcall_t fn);
     144             : extern char __initdata boot_command_line[];
     145             : extern char *saved_command_line;
     146             : extern unsigned int reset_devices;
     147             : 
     148             : /* used by init/main.c */
     149             : void setup_arch(char **);
     150             : void prepare_namespace(void);
     151             : void __init init_rootfs(void);
     152             : extern struct file_system_type rootfs_fs_type;
     153             : 
     154             : #if defined(CONFIG_STRICT_KERNEL_RWX) || defined(CONFIG_STRICT_MODULE_RWX)
     155             : extern bool rodata_enabled;
     156             : #endif
     157             : #ifdef CONFIG_STRICT_KERNEL_RWX
     158             : void mark_rodata_ro(void);
     159             : #endif
     160             : 
     161             : extern void (*late_time_init)(void);
     162             : 
     163             : extern bool initcall_debug;
     164             : 
     165             : #endif
     166             :   
     167             : #ifndef MODULE
     168             : 
     169             : #ifndef __ASSEMBLY__
     170             : 
     171             : /*
     172             :  * initcalls are now grouped by functionality into separate
     173             :  * subsections. Ordering inside the subsections is determined
     174             :  * by link order. 
     175             :  * For backwards compatibility, initcall() puts the call in 
     176             :  * the device init subsection.
     177             :  *
     178             :  * The `id' arg to __define_initcall() is needed so that multiple initcalls
     179             :  * can point at the same handler without causing duplicate-symbol build errors.
     180             :  *
     181             :  * Initcalls are run by placing pointers in initcall sections that the
     182             :  * kernel iterates at runtime. The linker can do dead code / data elimination
     183             :  * and remove that completely, so the initcall sections have to be marked
     184             :  * as KEEP() in the linker script.
     185             :  */
     186             : 
     187             : /* Format: <modname>__<counter>_<line>_<fn> */
     188             : #define __initcall_id(fn)                                       \
     189             :         __PASTE(__KBUILD_MODNAME,                               \
     190             :         __PASTE(__,                                             \
     191             :         __PASTE(__COUNTER__,                                    \
     192             :         __PASTE(_,                                              \
     193             :         __PASTE(__LINE__,                                       \
     194             :         __PASTE(_, fn))))))
     195             : 
     196             : /* Format: __<prefix>__<iid><id> */
     197             : #define __initcall_name(prefix, __iid, id)                      \
     198             :         __PASTE(__,                                             \
     199             :         __PASTE(prefix,                                         \
     200             :         __PASTE(__,                                             \
     201             :         __PASTE(__iid, id))))
     202             : 
     203             : #ifdef CONFIG_LTO_CLANG
     204             : /*
     205             :  * With LTO, the compiler doesn't necessarily obey link order for
     206             :  * initcalls. In order to preserve the correct order, we add each
     207             :  * variable into its own section and generate a linker script (in
     208             :  * scripts/link-vmlinux.sh) to specify the order of the sections.
     209             :  */
     210             : #define __initcall_section(__sec, __iid)                        \
     211             :         #__sec ".init.." #__iid
     212             : 
     213             : /*
     214             :  * With LTO, the compiler can rename static functions to avoid
     215             :  * global naming collisions. We use a global stub function for
     216             :  * initcalls to create a stable symbol name whose address can be
     217             :  * taken in inline assembly when PREL32 relocations are used.
     218             :  */
     219             : #define __initcall_stub(fn, __iid, id)                          \
     220             :         __initcall_name(initstub, __iid, id)
     221             : 
     222             : #define __define_initcall_stub(__stub, fn)                      \
     223             :         int __init __stub(void);                                \
     224             :         int __init __stub(void)                                 \
     225             :         {                                                       \
     226             :                 return fn();                                    \
     227             :         }                                                       \
     228             :         __ADDRESSABLE(__stub)
     229             : #else
     230             : #define __initcall_section(__sec, __iid)                        \
     231             :         #__sec ".init"
     232             : 
     233             : #define __initcall_stub(fn, __iid, id)  fn
     234             : 
     235             : #define __define_initcall_stub(__stub, fn)                      \
     236             :         __ADDRESSABLE(fn)
     237             : #endif
     238             : 
     239             : #ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
     240             : #define ____define_initcall(fn, __stub, __name, __sec)          \
     241             :         __define_initcall_stub(__stub, fn)                      \
     242             :         asm(".section      \"" __sec "\", \"a\"              \n"        \
     243             :             __stringify(__name) ":                 \n"        \
     244             :             ".long " __stringify(__stub) " - .   \n"        \
     245             :             ".previous                                     \n");
     246             : #else
     247             : #define ____define_initcall(fn, __unused, __name, __sec)        \
     248             :         static initcall_t __name __used                         \
     249             :                 __attribute__((__section__(__sec))) = fn;
     250             : #endif
     251             : 
     252             : #define __unique_initcall(fn, id, __sec, __iid)                 \
     253             :         ____define_initcall(fn,                                 \
     254             :                 __initcall_stub(fn, __iid, id),                 \
     255             :                 __initcall_name(initcall, __iid, id),           \
     256             :                 __initcall_section(__sec, __iid))
     257             : 
     258             : #define ___define_initcall(fn, id, __sec)                       \
     259             :         __unique_initcall(fn, id, __sec, __initcall_id(fn))
     260             : 
     261             : #define __define_initcall(fn, id) ___define_initcall(fn, id, .initcall##id)
     262             : 
     263             : /*
     264             :  * Early initcalls run before initializing SMP.
     265             :  *
     266             :  * Only for built-in code, not modules.
     267             :  */
     268             : #define early_initcall(fn)              __define_initcall(fn, early)
     269             : 
     270             : /*
     271             :  * A "pure" initcall has no dependencies on anything else, and purely
     272             :  * initializes variables that couldn't be statically initialized.
     273             :  *
     274             :  * This only exists for built-in code, not for modules.
     275             :  * Keep main.c:initcall_level_names[] in sync.
     276             :  */
     277             : #define pure_initcall(fn)               __define_initcall(fn, 0)
     278             : 
     279             : #define core_initcall(fn)               __define_initcall(fn, 1)
     280             : #define core_initcall_sync(fn)          __define_initcall(fn, 1s)
     281             : #define postcore_initcall(fn)           __define_initcall(fn, 2)
     282             : #define postcore_initcall_sync(fn)      __define_initcall(fn, 2s)
     283             : #define arch_initcall(fn)               __define_initcall(fn, 3)
     284             : #define arch_initcall_sync(fn)          __define_initcall(fn, 3s)
     285             : #define subsys_initcall(fn)             __define_initcall(fn, 4)
     286             : #define subsys_initcall_sync(fn)        __define_initcall(fn, 4s)
     287             : #define fs_initcall(fn)                 __define_initcall(fn, 5)
     288             : #define fs_initcall_sync(fn)            __define_initcall(fn, 5s)
     289             : #define rootfs_initcall(fn)             __define_initcall(fn, rootfs)
     290             : #define device_initcall(fn)             __define_initcall(fn, 6)
     291             : #define device_initcall_sync(fn)        __define_initcall(fn, 6s)
     292             : #define late_initcall(fn)               __define_initcall(fn, 7)
     293             : #define late_initcall_sync(fn)          __define_initcall(fn, 7s)
     294             : 
     295             : #define __initcall(fn) device_initcall(fn)
     296             : 
     297             : #define __exitcall(fn)                                          \
     298             :         static exitcall_t __exitcall_##fn __exit_call = fn
     299             : 
     300             : #define console_initcall(fn)    ___define_initcall(fn, con, .con_initcall)
     301             : 
     302             : struct obs_kernel_param {
     303             :         const char *str;
     304             :         int (*setup_func)(char *);
     305             :         int early;
     306             : };
     307             : 
     308             : /*
     309             :  * Only for really core code.  See moduleparam.h for the normal way.
     310             :  *
     311             :  * Force the alignment so the compiler doesn't space elements of the
     312             :  * obs_kernel_param "array" too far apart in .init.setup.
     313             :  */
     314             : #define __setup_param(str, unique_id, fn, early)                        \
     315             :         static const char __setup_str_##unique_id[] __initconst         \
     316             :                 __aligned(1) = str;                                     \
     317             :         static struct obs_kernel_param __setup_##unique_id              \
     318             :                 __used __section(".init.setup")                               \
     319             :                 __aligned(__alignof__(struct obs_kernel_param))         \
     320             :                 = { __setup_str_##unique_id, fn, early }
     321             : 
     322             : #define __setup(str, fn)                                                \
     323             :         __setup_param(str, fn, fn, 0)
     324             : 
     325             : /*
     326             :  * NOTE: fn is as per module_param, not __setup!
     327             :  * Emits warning if fn returns non-zero.
     328             :  */
     329             : #define early_param(str, fn)                                            \
     330             :         __setup_param(str, fn, fn, 1)
     331             : 
     332             : #define early_param_on_off(str_on, str_off, var, config)                \
     333             :                                                                         \
     334             :         int var = IS_ENABLED(config);                                   \
     335             :                                                                         \
     336             :         static int __init parse_##var##_on(char *arg)                   \
     337             :         {                                                               \
     338             :                 var = 1;                                                \
     339             :                 return 0;                                               \
     340             :         }                                                               \
     341             :         early_param(str_on, parse_##var##_on);                          \
     342             :                                                                         \
     343             :         static int __init parse_##var##_off(char *arg)                  \
     344             :         {                                                               \
     345             :                 var = 0;                                                \
     346             :                 return 0;                                               \
     347             :         }                                                               \
     348             :         early_param(str_off, parse_##var##_off)
     349             : 
     350             : /* Relies on boot_command_line being set */
     351             : void __init parse_early_param(void);
     352             : void __init parse_early_options(char *cmdline);
     353             : #endif /* __ASSEMBLY__ */
     354             : 
     355             : #else /* MODULE */
     356             : 
     357             : #define __setup_param(str, unique_id, fn)       /* nothing */
     358             : #define __setup(str, func)                      /* nothing */
     359             : #endif
     360             : 
     361             : /* Data marked not to be saved by software suspend */
     362             : #define __nosavedata __section(".data..nosave")
     363             : 
     364             : #ifdef MODULE
     365             : #define __exit_p(x) x
     366             : #else
     367             : #define __exit_p(x) NULL
     368             : #endif
     369             : 
     370             : #endif /* _LINUX_INIT_H */

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