255 lines
7.4 KiB
C
255 lines
7.4 KiB
C
#include "tasking_helpers.h"
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#include "tasking.h"
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#include "../tasking.h"
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#include "isr.h"
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#include <stdio.h>
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#include <string.h>
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#include "kmalloc.h"
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#include "memory.h"
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#include "gdt.h"
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#include "paging.h"
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#include <stdint.h>
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#include <stdlib.h>
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#include "../halt.h"
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#include "serial.h"
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#include "../../vga_err.h"
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#include <sys/types.h>
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#define STACK_PAGES 2
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extern void task_init();
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static uint32_t* kstacks=(uint32_t*)0xF6800000;
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uint32_t next_pid=0;
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uint32_t running_blocked_tasks=0;
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Task* currentTask=NULL;
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static Task* readyToRunHead=NULL;
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static Task* readyToRunTail=NULL;
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static Task* exitedTasksHead=NULL;
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static Task* exitedTasksTail=NULL;
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static Task* tasks[32768];
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Task* tasking_createTaskCr3KmodeParam(void* eip,void* cr3,char kmode,char param1_exists,uint32_t param1_arg,char param2_exists,uint32_t param2_arg);
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void tasking_init(void* esp) {
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tasking_createTaskCr3KmodeParam(NULL,paging_new_address_space(),1,0,0,0,0);
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}
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Task* tasking_createTaskCr3KmodeParam(void* eip,void* cr3,char kmode,char param1_exists,uint32_t param1_arg,char param2_exists,uint32_t param2_arg) {
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if (next_pid>1024*32) {
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serial_printf("Failed to create a task, as 32k tasks have been created already.\n");
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halt(); //Cannot ever create more than 32k tasks, as I don't currently reuse PIDs.
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}
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Task* task=kmalloc(sizeof(Task));
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map_kstack(next_pid);
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uint32_t param1;
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if (param1_exists) {
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param1=param1_arg;
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} else {
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param1=1;
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}
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uint32_t param2;
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if (param2_exists) {
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param2=param2_arg;
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} else {
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param2=2;
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}
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task->cr3=(uint32_t)cr3;
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uint32_t old_cr3;
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asm volatile("movl %%cr3, %%eax; movl %%eax, %0;":"=m"(old_cr3)::"%eax");
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load_address_space(task->cr3);
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if (kmode) {
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uint32_t top_idx=(1024*(next_pid+1));
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task->kernel_esp=((uint32_t)(&kstacks[top_idx-5]));
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task->kernel_esp_top=task->kernel_esp;
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kstacks[top_idx-5]=0;
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kstacks[top_idx-4]=0;
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kstacks[top_idx-3]=0;
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kstacks[top_idx-2]=0;
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kstacks[top_idx-1]=(uint32_t)eip;
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} else {
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uint32_t top_idx=(1024*(next_pid+1));
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task->kernel_esp=((uint32_t)(&kstacks[top_idx-7]));
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task->kernel_esp_top=task->kernel_esp;
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kstacks[top_idx-7]=0;
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kstacks[top_idx-6]=0;
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kstacks[top_idx-5]=0;
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kstacks[top_idx-4]=0;
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kstacks[top_idx-3]=(uint32_t)task_init;
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uint32_t* user_stack=(uint32_t*)(((uint32_t)alloc_pages(2))+0x2000);
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int buffer_pg_num=(((uint32_t)user_stack)-0x2000)>>12;
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make_protector(buffer_pg_num);
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// uint32_t* user_stack=(uint32_t*)(((uint32_t)alloc_pages(1))+0x1000);
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user_stack-=2;
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user_stack[0]=param1;
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user_stack[1]=param2;
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kstacks[top_idx-2]=(uint32_t)user_stack;
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kstacks[top_idx-1]=(uint32_t)eip;
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}
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load_address_space(old_cr3);
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task->next=NULL;
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task->pid=next_pid;
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task->priv=0;
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task->errno=0;
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if (currentTask) {
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task->priv=currentTask->priv;
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}
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if (task->pid==1) {
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task->priv=1;
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}
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task->prev=NULL;
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task->next=NULL;
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if (readyToRunTail) {
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task->state=TASK_READY;
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readyToRunTail->next=task;
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task->prev=readyToRunTail;
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readyToRunTail=task;
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} else if (currentTask) {
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task->state=TASK_READY;
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readyToRunHead=task;
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readyToRunTail=task;
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} else {
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task->state=TASK_RUNNING;
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currentTask=task;
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}
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tasks[next_pid]=task;
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next_pid++;
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running_blocked_tasks++;
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if (task->pid!=0) {
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serial_printf("Created task with PID %d.\n",task->pid);
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}
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return task;
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}
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int* tasking_get_errno_address() {
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return &(currentTask->errno);
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}
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char isPrivleged(uint32_t pid) {
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for (Task* task=readyToRunHead;task!=NULL;task=task->next) {
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if (task->pid==pid) {
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return task->priv;
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}
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}
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return 0;
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}
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Task* tasking_createTask(void* eip) {
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return tasking_createTaskCr3KmodeParam(eip,paging_new_address_space(),0,0,0,0,0);
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}
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void switch_to_task(Task* task) {
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if (task!=readyToRunHead) {
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// Unlink it from the doubly-linked list of ready-to-run tasks
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task->prev->next=task->next;
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if (task->next) {
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task->next->prev=task->prev;
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}
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} else {
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// Unlink the task from the list by advancing the ready to run pointer to the next task
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readyToRunHead=task->next;
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// If the task did not have a next task, also clear the ready to run tail pointer
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if (readyToRunHead==NULL) {
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readyToRunTail=NULL;
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}
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}
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task->prev=NULL;
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task->next=NULL;
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task->state=TASK_RUNNING;
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if (currentTask->state==TASK_RUNNING) {
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currentTask->state=TASK_READY;
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// Link the task onto the list of ready to run tasks
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if (readyToRunTail) {
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currentTask->prev=readyToRunTail;
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readyToRunTail->next=currentTask;
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readyToRunTail=currentTask;
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} else {
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readyToRunHead=currentTask;
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readyToRunTail=currentTask;
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}
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}
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serial_printf("Yielding to PID %d.\n",task->pid);
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load_smap(task->cr3);
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switch_to_task_asm(task);
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}
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void tasking_yield(pid_t pid) {
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if (pid==0) {
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if (!readyToRunHead) {
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if (currentTask->state!=TASK_RUNNING) {
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//This indicates either all tasks are bloked or the os has shutdown. Check which one it is
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if (running_blocked_tasks==0) {
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serial_printf("All tasks exited, halting\n");
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halt(); //never returns, so we dont need an else
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}
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serial_printf("All tasks blocked, waiting for interrupt to unblock task\n");
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// All tasks blocked
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// Stop running the current task by setting currentTask to null, though put it in a local variable to keep track of it.
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Task* task=currentTask;
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currentTask=NULL;
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// Wait for an IRQ whose handler unblocks a task
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do {
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asm volatile("sti");
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asm volatile("hlt");
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asm volatile("cli");
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} while (readyToRunHead==NULL);
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currentTask=task;
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} else {
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serial_printf("Yield failed, no other ready tasks\n");
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return;
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}
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}
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switch_to_task(readyToRunHead);
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} else {
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serial_printf("Attempting to yield to PID %d",pid);
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Task* task=tasks[pid];
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if (!task) {
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serial_printf("PID %d does not exist.\n",pid);
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return;
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}
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if (task->state!=TASK_READY) {
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serial_printf("PID %d is blocked");
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return;
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}
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switch_to_task(task);
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}
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}
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void tasking_exit(uint8_t code) {
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serial_printf("PID %d is exiting with code %d.\n",currentTask->pid,code);
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currentTask->state=TASK_EXITED;
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if (exitedTasksHead) {
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exitedTasksTail->next=currentTask;
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currentTask->prev=exitedTasksHead;
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exitedTasksTail=currentTask;
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} else {
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exitedTasksHead=currentTask;
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exitedTasksTail=currentTask;
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}
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running_blocked_tasks--;
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tasking_yield(0);
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}
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uint32_t getPID() {
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return currentTask->pid;
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}
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void tasking_block(TaskState newstate) {
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if (newstate==TASK_RUNNING || newstate==TASK_READY || newstate==TASK_EXITED) {
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serial_printf("Attempted to block task using a new state of running/ready/exited. This is an error.\n");
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return;
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}
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serial_printf("Blocking PID %d with state %d\n",currentTask->pid,currentTask->state);
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currentTask->state = newstate;
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tasking_yield(0);
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}
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void tasking_unblock(pid_t pid) {
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serial_printf("Unblocking PID %d\n",pid);
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tasks[pid]->state=TASK_READY;
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if(readyToRunHead) {
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readyToRunTail->next=tasks[pid];
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readyToRunTail=tasks[pid];
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} else {
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readyToRunHead=tasks[pid];
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readyToRunTail=tasks[pid];
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}
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}
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