root/init/init_task.c
// SPDX-License-Identifier: GPL-2.0
#include <linux/init_task.h>
#include <linux/export.h>
#include <linux/mqueue.h>
#include <linux/sched.h>
#include <linux/sched/sysctl.h>
#include <linux/sched/rt.h>
#include <linux/sched/task.h>
#include <linux/sched/ext.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/audit.h>
#include <linux/numa.h>
#include <linux/scs.h>
#include <linux/plist.h>

#include <linux/uaccess.h>

static struct signal_struct init_signals = {
        .nr_threads     = 1,
        .thread_head    = LIST_HEAD_INIT(init_task.thread_node),
        .wait_chldexit  = __WAIT_QUEUE_HEAD_INITIALIZER(init_signals.wait_chldexit),
        .shared_pending = {
                .list = LIST_HEAD_INIT(init_signals.shared_pending.list),
                .signal =  {{0}}
        },
        .multiprocess   = HLIST_HEAD_INIT,
        .rlim           = INIT_RLIMITS,
#ifdef CONFIG_CGROUPS
        .cgroup_threadgroup_rwsem       = __RWSEM_INITIALIZER(init_signals.cgroup_threadgroup_rwsem),
#endif
        .cred_guard_mutex = __MUTEX_INITIALIZER(init_signals.cred_guard_mutex),
        .exec_update_lock = __RWSEM_INITIALIZER(init_signals.exec_update_lock),
#ifdef CONFIG_POSIX_TIMERS
        .posix_timers           = HLIST_HEAD_INIT,
        .ignored_posix_timers   = HLIST_HEAD_INIT,
        .cputimer               = {
                .cputime_atomic = INIT_CPUTIME_ATOMIC,
        },
#endif
        INIT_CPU_TIMERS(init_signals)
        .pids = {
                [PIDTYPE_PID]   = &init_struct_pid,
                [PIDTYPE_TGID]  = &init_struct_pid,
                [PIDTYPE_PGID]  = &init_struct_pid,
                [PIDTYPE_SID]   = &init_struct_pid,
        },
        INIT_PREV_CPUTIME(init_signals)
};

static struct sighand_struct init_sighand = {
        .count          = REFCOUNT_INIT(1),
        .action         = { { { .sa_handler = SIG_DFL, } }, },
        .siglock        = __SPIN_LOCK_UNLOCKED(init_sighand.siglock),
        .signalfd_wqh   = __WAIT_QUEUE_HEAD_INITIALIZER(init_sighand.signalfd_wqh),
};

#ifdef CONFIG_SHADOW_CALL_STACK
unsigned long init_shadow_call_stack[SCS_SIZE / sizeof(long)] = {
        [(SCS_SIZE / sizeof(long)) - 1] = SCS_END_MAGIC
};
#endif

/* init to 2 - one for init_task, one to ensure it is never freed */
static struct group_info init_groups = { .usage = REFCOUNT_INIT(2) };

/*
 * The initial credentials for the initial task
 */
static struct cred init_cred = {
        .usage                  = ATOMIC_INIT(4),
        .uid                    = GLOBAL_ROOT_UID,
        .gid                    = GLOBAL_ROOT_GID,
        .suid                   = GLOBAL_ROOT_UID,
        .sgid                   = GLOBAL_ROOT_GID,
        .euid                   = GLOBAL_ROOT_UID,
        .egid                   = GLOBAL_ROOT_GID,
        .fsuid                  = GLOBAL_ROOT_UID,
        .fsgid                  = GLOBAL_ROOT_GID,
        .securebits             = SECUREBITS_DEFAULT,
        .cap_inheritable        = CAP_EMPTY_SET,
        .cap_permitted          = CAP_FULL_SET,
        .cap_effective          = CAP_FULL_SET,
        .cap_bset               = CAP_FULL_SET,
        .user                   = INIT_USER,
        .user_ns                = &init_user_ns,
        .group_info             = &init_groups,
        .ucounts                = &init_ucounts,
};

/*
 * Set up the first task table, touch at your own risk!. Base=0,
 * limit=0x1fffff (=2MB)
 */
struct task_struct init_task __aligned(L1_CACHE_BYTES) = {
#ifdef CONFIG_THREAD_INFO_IN_TASK
        .thread_info    = INIT_THREAD_INFO(init_task),
        .stack_refcount = REFCOUNT_INIT(1),
#endif
        .__state        = 0,
        .stack          = init_stack,
        .usage          = REFCOUNT_INIT(2),
        .flags          = PF_KTHREAD,
        .prio           = MAX_PRIO - 20,
        .static_prio    = MAX_PRIO - 20,
        .normal_prio    = MAX_PRIO - 20,
        .policy         = SCHED_NORMAL,
        .cpus_ptr       = &init_task.cpus_mask,
        .user_cpus_ptr  = NULL,
        .cpus_mask      = CPU_MASK_ALL,
        .max_allowed_capacity   = SCHED_CAPACITY_SCALE,
        .nr_cpus_allowed= NR_CPUS,
        .mm             = NULL,
        .active_mm      = &init_mm,
        .restart_block  = {
                .fn = do_no_restart_syscall,
        },
        .se             = {
                .group_node     = LIST_HEAD_INIT(init_task.se.group_node),
        },
        .rt             = {
                .run_list       = LIST_HEAD_INIT(init_task.rt.run_list),
                .time_slice     = RR_TIMESLICE,
        },
        .tasks          = LIST_HEAD_INIT(init_task.tasks),
#ifdef CONFIG_SMP
        .pushable_tasks = PLIST_NODE_INIT(init_task.pushable_tasks, MAX_PRIO),
#endif
#ifdef CONFIG_CGROUP_SCHED
        .sched_task_group = &root_task_group,
#endif
#ifdef CONFIG_SCHED_CLASS_EXT
        .scx            = {
                .dsq_list.node  = LIST_HEAD_INIT(init_task.scx.dsq_list.node),
                .sticky_cpu     = -1,
                .holding_cpu    = -1,
                .runnable_node  = LIST_HEAD_INIT(init_task.scx.runnable_node),
                .runnable_at    = INITIAL_JIFFIES,
                .ddsp_dsq_id    = SCX_DSQ_INVALID,
                .slice          = SCX_SLICE_DFL,
        },
#endif
        .ptraced        = LIST_HEAD_INIT(init_task.ptraced),
        .ptrace_entry   = LIST_HEAD_INIT(init_task.ptrace_entry),
        .real_parent    = &init_task,
        .parent         = &init_task,
        .children       = LIST_HEAD_INIT(init_task.children),
        .sibling        = LIST_HEAD_INIT(init_task.sibling),
        .group_leader   = &init_task,
        RCU_POINTER_INITIALIZER(real_cred, &init_cred),
        RCU_POINTER_INITIALIZER(cred, &init_cred),
        .comm           = INIT_TASK_COMM,
        .thread         = INIT_THREAD,
        .fs             = &init_fs,
        .files          = &init_files,
#ifdef CONFIG_IO_URING
        .io_uring       = NULL,
#endif
        .signal         = &init_signals,
        .sighand        = &init_sighand,
        .nsproxy        = &init_nsproxy,
        .pending        = {
                .list = LIST_HEAD_INIT(init_task.pending.list),
                .signal = {{0}}
        },
        .blocked        = {{0}},
        .alloc_lock     = __SPIN_LOCK_UNLOCKED(init_task.alloc_lock),
        .journal_info   = NULL,
        INIT_CPU_TIMERS(init_task)
        .pi_lock        = __RAW_SPIN_LOCK_UNLOCKED(init_task.pi_lock),
        .timer_slack_ns = 50000, /* 50 usec default slack */
        .thread_pid     = &init_struct_pid,
        .thread_node    = LIST_HEAD_INIT(init_signals.thread_head),
#ifdef CONFIG_AUDIT
        .loginuid       = INVALID_UID,
        .sessionid      = AUDIT_SID_UNSET,
#endif
#ifdef CONFIG_PERF_EVENTS
        .perf_event_mutex = __MUTEX_INITIALIZER(init_task.perf_event_mutex),
        .perf_event_list = LIST_HEAD_INIT(init_task.perf_event_list),
#endif
#ifdef CONFIG_PREEMPT_RCU
        .rcu_read_lock_nesting = 0,
        .rcu_read_unlock_special.s = 0,
        .rcu_node_entry = LIST_HEAD_INIT(init_task.rcu_node_entry),
        .rcu_blocked_node = NULL,
#endif
#ifdef CONFIG_TASKS_RCU
        .rcu_tasks_holdout = false,
        .rcu_tasks_holdout_list = LIST_HEAD_INIT(init_task.rcu_tasks_holdout_list),
        .rcu_tasks_idle_cpu = -1,
        .rcu_tasks_exit_list = LIST_HEAD_INIT(init_task.rcu_tasks_exit_list),
#endif
#ifdef CONFIG_TASKS_TRACE_RCU
        .trc_reader_nesting = 0,
#endif
#ifdef CONFIG_CPUSETS
        .mems_allowed_seq = SEQCNT_SPINLOCK_ZERO(init_task.mems_allowed_seq,
                                                 &init_task.alloc_lock),
#endif
#ifdef CONFIG_RT_MUTEXES
        .pi_waiters     = RB_ROOT_CACHED,
        .pi_top_task    = NULL,
#endif
        INIT_PREV_CPUTIME(init_task)
#ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
        .vtime.seqcount = SEQCNT_ZERO(init_task.vtime_seqcount),
        .vtime.starttime = 0,
        .vtime.state    = VTIME_SYS,
#endif
#ifdef CONFIG_NUMA_BALANCING
        .numa_preferred_nid = NUMA_NO_NODE,
        .numa_group     = NULL,
        .numa_faults    = NULL,
#endif
#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
        .kasan_depth    = 1,
#endif
#ifdef CONFIG_KCSAN
        .kcsan_ctx = {
                .scoped_accesses        = {LIST_POISON1, NULL},
        },
#endif
#ifdef CONFIG_TRACE_IRQFLAGS
        .softirqs_enabled = 1,
#endif
#ifdef CONFIG_LOCKDEP
        .lockdep_depth = 0, /* no locks held yet */
        .curr_chain_key = INITIAL_CHAIN_KEY,
        .lockdep_recursion = 0,
#endif
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
        .ret_stack              = NULL,
        .tracing_graph_pause    = ATOMIC_INIT(0),
#endif
#if defined(CONFIG_TRACING) && defined(CONFIG_PREEMPTION)
        .trace_recursion = 0,
#endif
#ifdef CONFIG_LIVEPATCH
        .patch_state    = KLP_TRANSITION_IDLE,
#endif
#ifdef CONFIG_SECURITY
        .security       = NULL,
#endif
#ifdef CONFIG_SECCOMP_FILTER
        .seccomp        = { .filter_count = ATOMIC_INIT(0) },
#endif
#ifdef CONFIG_SCHED_MM_CID
        .mm_cid         = { .cid = MM_CID_UNSET, },
#endif
};
EXPORT_SYMBOL(init_task);

/*
 * Initial thread structure. Alignment of this is handled by a special
 * linker map entry.
 */
#ifndef CONFIG_THREAD_INFO_IN_TASK
struct thread_info init_thread_info __init_thread_info = INIT_THREAD_INFO(init_task);
#endif