osfmk/kern/startup.h

   1 /*
   2  * Copyright (c) 2000-2020 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
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  23  * Please see the License for the specific language governing rights and
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  27  */
  28 /*
  29  * @OSF_COPYRIGHT@
  30  */
  31
  32 #ifdef  XNU_KERNEL_PRIVATE
  33
  34 #ifndef _KERN_STARTUP_H_
  35 #define _KERN_STARTUP_H_
  36
  37 #include <stdbool.h>
  38 #include <stdint.h>
  39
  40 #include <libkern/section_keywords.h>
  41
  42 __BEGIN_DECLS
  43
  44 #pragma GCC visibility push(hidden)
  45
  46 /*!
  47  * @enum startup_subsystem_id_t
  48  *
  49  * @abstract
  50  * Represents a stage of kernel intialization, ubnd allows for subsystems
  51  * to register initializers for a specific stage.
  52  *
  53  * @discussion
  54  * Documentation of each subsystem initialization sequence exists in
  55  * @file doc/startup.md.
  56  */
  57 __enum_decl(startup_subsystem_id_t, uint32_t, {
  58         STARTUP_SUB_NONE = 0,         /**< reserved for the startup subsystem  */
  59
  60         STARTUP_SUB_TUNABLES,         /**< support for the tunables subsystem  */
  61         STARTUP_SUB_LOCKS_EARLY,      /**< early locking, before zalloc        */
  62         STARTUP_SUB_KPRINTF,          /**< kprintf initialization              */
  63
  64         STARTUP_SUB_PMAP_STEAL,       /**< to perform various pmap carveouts   */
  65         STARTUP_SUB_VM_KERNEL,        /**< once the kernel VM is ready         */
  66         STARTUP_SUB_KMEM,             /**< once kmem is ready                  */
  67         STARTUP_SUB_KMEM_ALLOC,       /**< once kmem_alloc is ready            */
  68         STARTUP_SUB_ZALLOC,           /**< initialize zalloc and kalloc        */
  69         STARTUP_SUB_PERCPU,           /**< initialize the percpu subsystem     */
  70         STARTUP_SUB_LOCKS,            /**< various subsystem locks             */
  71
  72         STARTUP_SUB_CODESIGNING,      /**< codesigning subsystem               */
  73         STARTUP_SUB_OSLOG,            /**< oslog and kernel loggging           */
  74         STARTUP_SUB_MACH_IPC,         /**< Mach IPC                            */
  75         STARTUP_SUB_EARLY_BOOT,       /**< interrupts/premption are turned on  */
  76
  77         STARTUP_SUB_LOCKDOWN = ~0u,   /**< reserved for the startup subsystem  */
  78 });
  79
  80 /*!
  81  * Stores the last subsystem to have been fully initialized;
  82  */
  83 extern startup_subsystem_id_t startup_phase;
  84
  85 /*!
  86  * @enum startup_debug_t
  87  *
  88  * @abstract
  89  * Flags set in the @c startup_debug global to configure startup debugging.
  90  */
  91 __options_decl(startup_debug_t, uint32_t, {
  92         STARTUP_DEBUG_NONE    = 0x00000000,
  93         STARTUP_DEBUG_VERBOSE = 0x00000001,
  94 });
  95
  96 #if DEBUG || DEVELOPMENT
  97 extern startup_debug_t startup_debug;
  98 #else
  99 #define startup_debug  STARTUP_DEBUG_NONE
 100 #endif
 101
 102 /*!
 103  * @enum startup_rank
 104  *
 105  * @abstract
 106  * Specifies in which rank a given initializer runs within a given section
 107  * to register initializers for a specific rank within the subsystem.
 108  *
 109  * @description
 110  * A startup function, declared with @c STARTUP or @c STARTUP_ARG, can specify
 111  * an rank within the subsystem they initialize.
 112  *
 113  * @c STARTUP_RANK_NTH(n) will let callbacks be run at stage @c n (0-based).
 114  *
 115  * @c STARTUP_RANK_FIRST, @c STARTUP_RANK_SECOND, @c STARTUP_RANK_THIRD and
 116  * @c STARTUP_RANK_FOURTH are given as conveniency names for these.
 117  *
 118  * @c STARTUP_RANK_MIDDLE is a reserved value that will let startup functions
 119  * run after all the @c STARTUP_RANK_NTH(n) ones have.
 120  *
 121  * @c STARTUP_RANK_NTH_LATE_NTH(n) will let callbacks be run then in @c n rank
 122  * after the @c STARTUP_RANK_MIDDLE ones (0-based).
 123  *
 124  * @c STARTUP_RANK_LAST callbacks will run absolutely last after everything
 125  * else did for this subsystem.
 126  */
 127 __enum_decl(startup_rank_t, uint32_t, {
 128 #define STARTUP_RANK_NTH(n) \
 129         (enum startup_rank)(n)
 130         STARTUP_RANK_FIRST          = 0,
 131         STARTUP_RANK_SECOND         = 1,
 132         STARTUP_RANK_THIRD          = 2,
 133         STARTUP_RANK_FOURTH         = 3,
 134
 135         STARTUP_RANK_MIDDLE         = 0x7fffffff,
 136
 137 #define STARTUP_RANK_LATE_NTH(n) \
 138         (enum startup_rank)(STARTUP_RANK_MIDDLE + 1 + (n))
 139
 140         STARTUP_RANK_LAST           = 0xffffffff,
 141 });
 142
 143 #if KASAN
 144 /*
 145  * The use of weird sections that get unmapped confuse the hell out of kasan,
 146  * so for KASAN leave things in regular __TEXT/__DATA segments
 147  */
 148 #define STARTUP_CODE_SEGSECT "__TEXT,__text"
 149 #define STARTUP_DATA_SEGSECT "__DATA,__init"
 150 #define STARTUP_HOOK_SEGMENT "__DATA"
 151 #define STARTUP_HOOK_SECTION "__init_entry_set"
 152 #elif defined(__x86_64__)
 153 /* Intel doesn't have a __BOOTDATA but doesn't protect __KLD */
 154 #define STARTUP_CODE_SEGSECT "__TEXT,__text"
 155 #define STARTUP_DATA_SEGSECT "__KLD,__init"
 156 #define STARTUP_HOOK_SEGMENT "__KLD"
 157 #define STARTUP_HOOK_SECTION "__init_entry_set"
 158 #else
 159 /* arm protects __KLD early, so use __BOOTDATA for data */
 160 #define STARTUP_CODE_SEGSECT "__TEXT,__text"
 161 #define STARTUP_DATA_SEGSECT "__BOOTDATA,__init"
 162 #define STARTUP_HOOK_SEGMENT "__BOOTDATA"
 163 #define STARTUP_HOOK_SECTION "__init_entry_set"
 164 #endif
 165
 166 /*!
 167  * @macro __startup_func
 168  *
 169  * @abstract
 170  * Attribute to place on functions used only during the kernel startup phase.
 171  *
 172  * @description
 173  * Code marked with this attribute will be unmapped after kernel lockdown.
 174  */
 175 #define __startup_func \
 176         __PLACE_IN_SECTION(STARTUP_CODE_SEGSECT) \
 177         __attribute__((noinline, visibility("hidden")))
 178
 179 /*!
 180  * @macro __startup_data
 181  *
 182  * @abstract
 183  * Attribute to place on globals used during the kernel startup phase.
 184  *
 185  * @description
 186  * Data marked with this attribute will be unmapped after kernel lockdown.
 187  */
 188 #define __startup_data \
 189         __PLACE_IN_SECTION(STARTUP_DATA_SEGSECT)
 190
 191 /*!
 192  * @macro STARTUP
 193  *
 194  * @abstract
 195  * Declares a kernel startup callback.
 196  */
 197 #define STARTUP(subsystem, rank, func) \
 198         __STARTUP(func, __LINE__, subsystem, rank, func)
 199
 200 /*!
 201  * @macro STARTUP_ARG
 202  *
 203  * @abstract
 204  * Declares a kernel startup callback that takes an argument.
 205  */
 206 #define STARTUP_ARG(subsystem, rank, func, arg) \
 207         __STARTUP_ARG(func, __LINE__, subsystem, rank, func, arg)
 208
 209 /*!
 210  * @macro TUNABLE
 211  *
 212  * @abstract
 213  * Declares a read-only kernel tunable that is read from a boot-arg with
 214  * a default value, without further processing.
 215  *
 216  * @param type_t
 217  * Should be an integer type or bool.
 218  *
 219  * @param var
 220  * The name of the C variable to use for storage.
 221  *
 222  * @param key
 223  * The name of the boot-arg to parse for initialization
 224  *
 225  * @param default_value
 226  * The default value for the tunable if the boot-arg is absent.
 227  */
 228 #define TUNABLE(type_t, var, key, default_value) \
 229         SECURITY_READ_ONLY_LATE(type_t) var = default_value; \
 230         __TUNABLE(type_t, var, key)
 231
 232 /*!
 233  * @macro TUNABLE_WRITEABLE
 234  *
 235  * @abstract
 236  * Declares a writeable kernel tunable that is read from a boot-arg with
 237  * a default value, without further processing.
 238  *
 239  * @param type_t
 240  * Should be an integer type or bool.
 241  *
 242  * @param var
 243  * The name of the C variable to use for storage.
 244  *
 245  * @param key
 246  * The name of the boot-arg to parse for initialization
 247  *
 248  * @param default_value
 249  * The default value for the tunable if the boot-arg is absent.
 250  */
 251 #define TUNABLE_WRITEABLE(type_t, var, key, default_value) \
 252         type_t var = default_value; \
 253         __TUNABLE(type_t, var, key)
 254
 255 #pragma mark - internals
 256
 257 #define __TUNABLE(type_t, var, key) \
 258         static __startup_data char __startup_TUNABLES_name_ ## var[] = key; \
 259         static __startup_data struct startup_tunable_spec \
 260         __startup_TUNABLES_spec_ ## var = { \
 261             .name = __startup_TUNABLES_name_ ## var, \
 262             .var_addr = &var, \
 263             .var_len = sizeof(type_t), \
 264             .var_is_bool = __builtin_types_compatible_p(bool, type_t), \
 265         }; \
 266         __STARTUP_ARG(var, __LINE__, TUNABLES, STARTUP_RANK_FIRST, \
 267             kernel_startup_tunable_init, &__startup_TUNABLES_spec_ ## var)
 268
 269
 270 #define __STARTUP1(name, line, subsystem, rank, func, a, b) \
 271         __PLACE_IN_SECTION(STARTUP_HOOK_SEGMENT "," STARTUP_HOOK_SECTION) \
 272         static const struct startup_entry \
 273         __startup_ ## subsystem ## _entry_ ## name ## _ ## line = { \
 274             STARTUP_SUB_ ## subsystem, \
 275             rank, (typeof(func(a))(*)(const void *))func, b, \
 276         }
 277
 278 #define __STARTUP(name, line, subsystem, rank, func) \
 279         __STARTUP1(name, line, subsystem, rank, func, , NULL)
 280
 281 #define __STARTUP_ARG(name, line, subsystem, rank, func, arg) \
 282         __STARTUP1(name, line, subsystem, rank, func, arg, arg)
 283
 284 struct startup_entry {
 285         startup_subsystem_id_t subsystem;
 286         startup_rank_t         rank;
 287         void                 (*func)(const void *);
 288         const void            *arg;
 289 };
 290
 291 struct startup_tunable_spec {
 292         const char *name;
 293         void       *var_addr;
 294         int         var_len;
 295         bool        var_is_bool;
 296 };
 297
 298 /*
 299  * Kernel and machine startup declarations
 300  */
 301
 302 /* Initialize kernel */
 303 extern void kernel_startup_bootstrap(void);
 304 extern void kernel_startup_initialize_upto(startup_subsystem_id_t upto);
 305 extern void kernel_startup_tunable_init(const struct startup_tunable_spec *);
 306 extern void kernel_bootstrap(void);
 307
 308 /* Initialize machine dependent stuff */
 309 extern void machine_init(void);
 310
 311 extern void slave_main(void *machine_param);
 312
 313 /*
 314  * The following must be implemented in machine dependent code.
 315  */
 316
 317 /* Slave cpu initialization */
 318 extern void slave_machine_init(void *machine_param);
 319
 320 /* Device subystem initialization */
 321 extern void device_service_create(void);
 322
 323 #ifdef  MACH_BSD
 324
 325 /* BSD subsystem initialization */
 326 extern void bsd_init(void);
 327 extern void bsd_early_init(void);
 328
 329 #endif  /* MACH_BSD */
 330
 331 #pragma GCC visibility pop
 332
 333 __END_DECLS
 334
 335 #endif  /* _KERN_STARTUP_H_ */
 336
 337 #endif  /* XNU_KERNEL_PRIVATE */