linux/init/init_task.c
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   1// SPDX-License-Identifier: GPL-2.0
   2#include <linux/init_task.h>
   3#include <linux/export.h>
   4#include <linux/mqueue.h>
   5#include <linux/sched.h>
   6#include <linux/sched/sysctl.h>
   7#include <linux/sched/rt.h>
   8#include <linux/sched/task.h>
   9#include <linux/init.h>
  10#include <linux/fs.h>
  11#include <linux/mm.h>
  12#include <linux/audit.h>
  13#include <linux/numa.h>
  14
  15#include <asm/pgtable.h>
  16#include <linux/uaccess.h>
  17
  18static struct signal_struct init_signals = {
  19        .nr_threads     = 1,
  20        .thread_head    = LIST_HEAD_INIT(init_task.thread_node),
  21        .wait_chldexit  = __WAIT_QUEUE_HEAD_INITIALIZER(init_signals.wait_chldexit),
  22        .shared_pending = {
  23                .list = LIST_HEAD_INIT(init_signals.shared_pending.list),
  24                .signal =  {{0}}
  25        },
  26        .multiprocess   = HLIST_HEAD_INIT,
  27        .rlim           = INIT_RLIMITS,
  28        .cred_guard_mutex = __MUTEX_INITIALIZER(init_signals.cred_guard_mutex),
  29#ifdef CONFIG_POSIX_TIMERS
  30        .posix_timers = LIST_HEAD_INIT(init_signals.posix_timers),
  31        .cputimer       = {
  32                .cputime_atomic = INIT_CPUTIME_ATOMIC,
  33                .running        = false,
  34                .checking_timer = false,
  35        },
  36#endif
  37        INIT_CPU_TIMERS(init_signals)
  38        .pids = {
  39                [PIDTYPE_PID]   = &init_struct_pid,
  40                [PIDTYPE_TGID]  = &init_struct_pid,
  41                [PIDTYPE_PGID]  = &init_struct_pid,
  42                [PIDTYPE_SID]   = &init_struct_pid,
  43        },
  44        INIT_PREV_CPUTIME(init_signals)
  45};
  46
  47static struct sighand_struct init_sighand = {
  48        .count          = REFCOUNT_INIT(1),
  49        .action         = { { { .sa_handler = SIG_DFL, } }, },
  50        .siglock        = __SPIN_LOCK_UNLOCKED(init_sighand.siglock),
  51        .signalfd_wqh   = __WAIT_QUEUE_HEAD_INITIALIZER(init_sighand.signalfd_wqh),
  52};
  53
  54/*
  55 * Set up the first task table, touch at your own risk!. Base=0,
  56 * limit=0x1fffff (=2MB)
  57 */
  58struct task_struct init_task
  59#ifdef CONFIG_ARCH_TASK_STRUCT_ON_STACK
  60        __init_task_data
  61#endif
  62= {
  63#ifdef CONFIG_THREAD_INFO_IN_TASK
  64        .thread_info    = INIT_THREAD_INFO(init_task),
  65        .stack_refcount = REFCOUNT_INIT(1),
  66#endif
  67        .state          = 0,
  68        .stack          = init_stack,
  69        .usage          = REFCOUNT_INIT(2),
  70        .flags          = PF_KTHREAD,
  71        .prio           = MAX_PRIO - 20,
  72        .static_prio    = MAX_PRIO - 20,
  73        .normal_prio    = MAX_PRIO - 20,
  74        .policy         = SCHED_NORMAL,
  75        .cpus_ptr       = &init_task.cpus_mask,
  76        .cpus_mask      = CPU_MASK_ALL,
  77        .nr_cpus_allowed= NR_CPUS,
  78        .mm             = NULL,
  79        .active_mm      = &init_mm,
  80        .restart_block  = {
  81                .fn = do_no_restart_syscall,
  82        },
  83        .se             = {
  84                .group_node     = LIST_HEAD_INIT(init_task.se.group_node),
  85        },
  86        .rt             = {
  87                .run_list       = LIST_HEAD_INIT(init_task.rt.run_list),
  88                .time_slice     = RR_TIMESLICE,
  89        },
  90        .tasks          = LIST_HEAD_INIT(init_task.tasks),
  91#ifdef CONFIG_SMP
  92        .pushable_tasks = PLIST_NODE_INIT(init_task.pushable_tasks, MAX_PRIO),
  93#endif
  94#ifdef CONFIG_CGROUP_SCHED
  95        .sched_task_group = &root_task_group,
  96#endif
  97        .ptraced        = LIST_HEAD_INIT(init_task.ptraced),
  98        .ptrace_entry   = LIST_HEAD_INIT(init_task.ptrace_entry),
  99        .real_parent    = &init_task,
 100        .parent         = &init_task,
 101        .children       = LIST_HEAD_INIT(init_task.children),
 102        .sibling        = LIST_HEAD_INIT(init_task.sibling),
 103        .group_leader   = &init_task,
 104        RCU_POINTER_INITIALIZER(real_cred, &init_cred),
 105        RCU_POINTER_INITIALIZER(cred, &init_cred),
 106        .comm           = INIT_TASK_COMM,
 107        .thread         = INIT_THREAD,
 108        .fs             = &init_fs,
 109        .files          = &init_files,
 110        .signal         = &init_signals,
 111        .sighand        = &init_sighand,
 112        .nsproxy        = &init_nsproxy,
 113        .pending        = {
 114                .list = LIST_HEAD_INIT(init_task.pending.list),
 115                .signal = {{0}}
 116        },
 117        .blocked        = {{0}},
 118        .alloc_lock     = __SPIN_LOCK_UNLOCKED(init_task.alloc_lock),
 119        .journal_info   = NULL,
 120        INIT_CPU_TIMERS(init_task)
 121        .pi_lock        = __RAW_SPIN_LOCK_UNLOCKED(init_task.pi_lock),
 122        .timer_slack_ns = 50000, /* 50 usec default slack */
 123        .thread_pid     = &init_struct_pid,
 124        .thread_group   = LIST_HEAD_INIT(init_task.thread_group),
 125        .thread_node    = LIST_HEAD_INIT(init_signals.thread_head),
 126#ifdef CONFIG_AUDIT
 127        .loginuid       = INVALID_UID,
 128        .sessionid      = AUDIT_SID_UNSET,
 129#endif
 130#ifdef CONFIG_PERF_EVENTS
 131        .perf_event_mutex = __MUTEX_INITIALIZER(init_task.perf_event_mutex),
 132        .perf_event_list = LIST_HEAD_INIT(init_task.perf_event_list),
 133#endif
 134#ifdef CONFIG_PREEMPT_RCU
 135        .rcu_read_lock_nesting = 0,
 136        .rcu_read_unlock_special.s = 0,
 137        .rcu_node_entry = LIST_HEAD_INIT(init_task.rcu_node_entry),
 138        .rcu_blocked_node = NULL,
 139#endif
 140#ifdef CONFIG_TASKS_RCU
 141        .rcu_tasks_holdout = false,
 142        .rcu_tasks_holdout_list = LIST_HEAD_INIT(init_task.rcu_tasks_holdout_list),
 143        .rcu_tasks_idle_cpu = -1,
 144#endif
 145#ifdef CONFIG_CPUSETS
 146        .mems_allowed_seq = SEQCNT_ZERO(init_task.mems_allowed_seq),
 147#endif
 148#ifdef CONFIG_RT_MUTEXES
 149        .pi_waiters     = RB_ROOT_CACHED,
 150        .pi_top_task    = NULL,
 151#endif
 152        INIT_PREV_CPUTIME(init_task)
 153#ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
 154        .vtime.seqcount = SEQCNT_ZERO(init_task.vtime_seqcount),
 155        .vtime.starttime = 0,
 156        .vtime.state    = VTIME_SYS,
 157#endif
 158#ifdef CONFIG_NUMA_BALANCING
 159        .numa_preferred_nid = NUMA_NO_NODE,
 160        .numa_group     = NULL,
 161        .numa_faults    = NULL,
 162#endif
 163#ifdef CONFIG_KASAN
 164        .kasan_depth    = 1,
 165#endif
 166#ifdef CONFIG_TRACE_IRQFLAGS
 167        .softirqs_enabled = 1,
 168#endif
 169#ifdef CONFIG_LOCKDEP
 170        .lockdep_depth = 0, /* no locks held yet */
 171        .curr_chain_key = INITIAL_CHAIN_KEY,
 172        .lockdep_recursion = 0,
 173#endif
 174#ifdef CONFIG_FUNCTION_GRAPH_TRACER
 175        .ret_stack      = NULL,
 176#endif
 177#if defined(CONFIG_TRACING) && defined(CONFIG_PREEMPT)
 178        .trace_recursion = 0,
 179#endif
 180#ifdef CONFIG_LIVEPATCH
 181        .patch_state    = KLP_UNDEFINED,
 182#endif
 183#ifdef CONFIG_SECURITY
 184        .security       = NULL,
 185#endif
 186};
 187EXPORT_SYMBOL(init_task);
 188
 189/*
 190 * Initial thread structure. Alignment of this is handled by a special
 191 * linker map entry.
 192 */
 193#ifndef CONFIG_THREAD_INFO_IN_TASK
 194struct thread_info init_thread_info __init_thread_info = INIT_THREAD_INFO(init_task);
 195#endif
 196