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| -rw-r--r-- | na/include/lume/task.h | 109 |
1 files changed, 109 insertions, 0 deletions
diff --git a/na/include/lume/task.h b/na/include/lume/task.h new file mode 100644 index 0000000..c87938c --- /dev/null +++ b/na/include/lume/task.h @@ -0,0 +1,109 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* Copyright (C) 2026 Richard Qin */ + +#pragma once + +/* + * Task Control Block & Task State + * + * Central representation of every execution context in LumeOS, + * whether kernel thread or (future) user process. + * + * Reference: docs/specs/task.md §3.1, docs/specs/scheduler.md §3.1 + */ + +#include <lume/types.h> +#include <lume/config.h> +#include <lume/list.h> +#include <arch/context.h> +#include <arch/trapframe.h> +#include <lume/waitqueue.h> + +/* Forward declarations */ +struct VmSpace; +struct SchedClass; + +/* ======================================================================== + * Task State Machine + * ======================================================================== */ + +enum class TaskState : uint8 { + Runnable = 0, // In a Per-CPU ready queue + Running = 1, // Currently executing on a CPU + Sleeping = 2, // Blocked on a WaitQueue + Zombie = 3, // Exited, waiting for parent wait() + Dead = 4, // Fully reclaimed, TCB can be freed +}; + +/* ======================================================================== + * Task Flags + * ======================================================================== */ + +inline constexpr uint8 TF_KTHREAD = 0x01; // Kernel thread (never enters user mode) +inline constexpr uint8 TF_IDLE = 0x02; // Idle thread +inline constexpr uint8 TF_INIT = 0x04; // init process (PID 1) + +inline constexpr int kExitCodeSignalFlag = 0x100; + +/* ======================================================================== + * Kernel Stack + * ======================================================================== */ + +inline constexpr uint64 kKernelStackSize = CONFIG_KERNEL_STACK_SIZE; +inline constexpr uint64 kStackCanary = 0xDEAD'BEEF'CAFE'BABEULL; + +/* ======================================================================== + * Task Control Block + * ======================================================================== */ + +struct TaskControlBlock { + /* ===== Scheduler hot fields (cache-line optimized) ===== */ + TaskState state; // Current state + uint8 priority; // Static priority [0, 31] + uint8 cpu_id; // Pinned CPU (Phase 2: no migration) + uint8 flags; // TF_KTHREAD | TF_IDLE | TF_INIT + + int32 time_slice; // Remaining time slice (ticks) + int32 pid; // Unique task ID (Linux: tid) + int32 tgid; // Thread group ID (Linux: pid) + + list_node run_link; // RunQueue list node + list_node all_link; // Global task list node + + /* ===== Context ===== */ + arch::Context context; // Callee-saved registers (scheduler switch) + arch::TrapFrame* trapframe; // Trap frame (user-mode entry/exit) + + /* ===== Kernel Stack ===== */ + uint64 kstack_pa; // Physical address + uint64 kstack_va; // Virtual address (stack bottom) + + /* ===== Address Space ===== */ + VmSpace* mm; // nullptr = kernel thread + + /* ===== Task Hierarchy ===== */ + TaskControlBlock* parent; + list_node children; // Children list head + list_node sibling; // Sibling list node + WaitQueue wait_chld; // Parent waits on this for children to exit + + /* ===== Exit ===== */ + int32 exit_code; + + /* ===== Scheduler class metadata ===== */ + const SchedClass* sched_class; + void* sched_entity; + + /* ===== Debug ===== */ + const char* name; +}; + +/* ======================================================================== + * current_task() — fast access to the running task on this CPU + * + * Must be called with interrupts disabled or while holding a spinlock. + * ======================================================================== */ +TaskControlBlock* current_task(); + +/* Terminate the current task with a signal. */ +void task_kill_current(int sig); |