84 lines
3.4 KiB
C
84 lines
3.4 KiB
C
/*
|
||
* task.h – Cooperative multitasking interface.
|
||
*
|
||
* Provides process control blocks (PCBs), a round-robin scheduler,
|
||
* and voluntary yield/exit primitives. Context switching is performed
|
||
* by the assembly routine in context_switch.S.
|
||
*/
|
||
|
||
#ifndef TASK_H
|
||
#define TASK_H
|
||
|
||
#include "kernel_types.h"
|
||
#include "boot_info.h"
|
||
|
||
/* ================================================================
|
||
* Configuration
|
||
* ================================================================ */
|
||
|
||
#define TASK_MAX 32 /* max concurrent tasks */
|
||
#define TASK_STACK_PAGES 8 /* 32 KB stack per task */
|
||
#define TASK_STACK_SIZE (TASK_STACK_PAGES * 4096)
|
||
#define TASK_NAME_LEN 32 /* max name length (CHAR16) */
|
||
|
||
/* ================================================================
|
||
* Task states
|
||
* ================================================================ */
|
||
|
||
typedef enum {
|
||
TASK_STATE_FREE = 0, /* PCB slot is unused */
|
||
TASK_STATE_READY, /* runnable, waiting to be scheduled */
|
||
TASK_STATE_RUNNING, /* currently executing on the CPU */
|
||
TASK_STATE_TERMINATED /* finished; slot will be recycled */
|
||
} TaskState;
|
||
|
||
/* ================================================================
|
||
* Task entry function
|
||
* ================================================================ */
|
||
|
||
/* Signature for the function a new task begins executing. */
|
||
typedef void (*TaskEntryFn)(void *arg);
|
||
|
||
/* ================================================================
|
||
* Process Control Block (PCB)
|
||
* ================================================================ */
|
||
|
||
typedef struct Task {
|
||
UINT32 pid; /* unique process ID */
|
||
TaskState state; /* current lifecycle state */
|
||
CHAR16 name[TASK_NAME_LEN]; /* human-readable label */
|
||
|
||
/* Context switch state */
|
||
UINT64 saved_rsp; /* RSP saved by context_switch() */
|
||
UINT64 stack_base; /* base phys addr of stack alloc */
|
||
UINTN stack_pages; /* stack size in pages */
|
||
|
||
/* Entry point */
|
||
TaskEntryFn entry; /* function pointer */
|
||
void *arg; /* argument passed to entry() */
|
||
|
||
/* Scheduling metadata */
|
||
UINTN switches; /* number of times scheduled */
|
||
} Task;
|
||
|
||
/* ================================================================
|
||
* Public API
|
||
* ================================================================ */
|
||
|
||
void task_init(BootInfo *Boot); /* initialise scheduler */
|
||
Task *task_create(const CHAR16 *name, /* spawn a new task */
|
||
TaskEntryFn entry, void *arg);
|
||
void task_yield(void); /* voluntarily give up the CPU */
|
||
void task_exit(void); /* terminate the current task */
|
||
Task *task_current(void); /* return the running task's PCB */
|
||
UINTN task_count(void); /* number of non-FREE tasks */
|
||
void task_print_list(BootInfo *Boot); /* print task table (for `ps`) */
|
||
|
||
/* Block the current task until the target task has finished. */
|
||
void task_wait(Task *t);
|
||
|
||
/* Assembly context switch (defined in context_switch.S). */
|
||
extern void context_switch(UINT64 *old_rsp, UINT64 new_rsp);
|
||
|
||
#endif /* TASK_H */
|