132 lines
3.2 KiB
C
132 lines
3.2 KiB
C
//
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// Created by rick on 22-02-21.
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//
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#include "task.h"
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#include <cpu/cpu.h>
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#include <stdbool.h>
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#include <libc/libc.h>
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#include <mem/malloc.h>
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#include <mem/pmm.h>
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#include <attributes.h>
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#define stack_end(task) ((task)->stack + ((task)->stack_page_count * PAGE_SIZE))
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typedef struct task {
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bool present: 1;
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uint8_t wait_irq: 4;
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uint32_t tid;
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struct task *next;
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void* stack;
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uint32_t stack_page_count;
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task_registers_t *task_registers;
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} task_t;
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typedef struct {
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task_registers_t task_registers;
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isr_registers_t isr_registers;
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task_entrypoint entrypoint;
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void *entry_data;
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char alignment[4];
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} packed task_stack_start;
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bool task_locked = false;
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task_t *first_task = NULL;
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task_t *last_task = NULL;
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task_t *current_task = NULL;
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uint32_t last_tid = 0;
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extern switch_task(task_registers_t**, task_registers_t*);
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extern cdecl noreturn void __task_entry_point();
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extern noreturn void __task_entry_point_inner();
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// explicit cdecl calling convention
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void cdecl noreturn task_entry_point(task_entrypoint entrypoint, void *entry_data) {
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entrypoint(entry_data);
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// task_end_self();
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while (true); // halt
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}
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void task_lock_acquire() {
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task_locked = true;
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}
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void task_lock_free() {
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task_locked = false;
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}
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void task_switch_next_inner(task_t *next_task) {
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if (task_locked) {
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return; // don't switch while the task is locked
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}
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if (next_task == current_task) {
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return;
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}
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task_t *previous_task = current_task;
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current_task = next_task;
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// switch task
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switch_task(previous_task == NULL ? NULL : &previous_task->task_registers, current_task->task_registers);
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}
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void task_start_first() {
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task_switch_next_inner(first_task);
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}
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void task_switch_next() {
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if (current_task == NULL) {
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return;
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}
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task_switch_next_inner(current_task->next == NULL ? first_task : current_task->next);
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}
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uint32_t task_spawn(task_entrypoint entrypoint, void *entry_data) {
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task_t *new_task = malloc(sizeof(task_t));
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memset((uint8_t *) new_task, 0, sizeof(task_t));
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new_task->tid = last_tid++;
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new_task->stack = pmm_get_pages(16);
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new_task->stack_page_count = 16;
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// todo check for null
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if (first_task == NULL) {
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// first task
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first_task = new_task;
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} else {
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last_task->next = new_task;
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}
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last_task = new_task;
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// prepare stack
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// cdecl format
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task_stack_start* stack = (task_stack_start *) (stack_end(new_task) - sizeof(task_stack_start));
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memset((uint8_t *) stack, 0, sizeof(task_stack_start));
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// setup isr return frame
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stack->isr_registers.cs = 0x08; // todo proper gdt setup
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stack->isr_registers.ds = 0x10; // todo
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// stack->isr_registers.ss = 0x10; // todo
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stack->isr_registers.eip = (uint32_t) __task_entry_point_inner;
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stack->isr_registers.eflags = 0x200;
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// setup task switch frame
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stack->task_registers.eip = (uint32_t) __task_entry_point;
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stack->task_registers.ebp = (uint32_t) stack_end(new_task);
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// setup entrypoint
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stack->entrypoint = entrypoint;
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stack->entry_data = entry_data;
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new_task->task_registers = &stack->task_registers;
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new_task->present = true;
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return new_task->tid;
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}
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void task_end(uint32_t pid) {
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}
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