os/kernel/cpu/i386/tasking.c

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#include "tasking_helpers.h"
#include "tasking.h"
#include "../tasking.h"
#include "isr.h"
#include <stdio.h>
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#include <string.h>
#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"
#include "serial.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;
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Task* currentTask;
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static Task* headTask;
static Task* tailTask;
static Task* tasks[32768];
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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currentTask=NULL;
next_pid=0;
headTask=tasking_createTaskCr3KmodeParam(NULL,paging_new_address_space(),1,0,0,0,0);
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currentTask=headTask;
tailTask=headTask;
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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) {
Task* task=kmalloc(sizeof(Task));
map_kstack(next_pid);
uint32_t param1;
if (param1_exists) {
param1=param1_arg;
} else {
param1=1;
}
uint32_t param2;
if (param2_exists) {
param2=param2_arg;
} else {
param2=2;
}
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task->cr3=(uint32_t)cr3;
uint32_t old_cr3;
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) {
uint32_t top_idx=(1024*(next_pid+1));
task->kernel_esp=((uint32_t)(&kstacks[top_idx-5]));
task->kernel_esp_top=task->kernel_esp;
kstacks[top_idx-5]=0;
kstacks[top_idx-4]=0;
kstacks[top_idx-3]=0;
kstacks[top_idx-2]=0;
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kstacks[top_idx-1]=(uint32_t)eip;
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} else {
uint32_t top_idx=(1024*(next_pid+1));
task->kernel_esp=((uint32_t)(&kstacks[top_idx-7]));
task->kernel_esp_top=task->kernel_esp;
kstacks[top_idx-7]=0;
kstacks[top_idx-6]=0;
kstacks[top_idx-5]=0;
kstacks[top_idx-4]=0;
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kstacks[top_idx-3]=(uint32_t)task_init;
uint32_t* user_stack=(uint32_t*)(((uint32_t)alloc_pages(1))+0x1000);
user_stack-=2;
user_stack[0]=param1;
user_stack[1]=param2;
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kstacks[top_idx-2]=(uint32_t)user_stack;
kstacks[top_idx-1]=(uint32_t)eip;
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}
load_address_space(old_cr3);
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task->next=NULL;
task->pid=next_pid;
tasks[next_pid]=task;
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task->priv=0;
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task->errno=0;
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if (currentTask) {
task->priv=currentTask->priv;
}
if (task->pid==1) {
task->priv=1;
}
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next_pid++;
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if (next_pid>1024*32) {
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.
}
if (tailTask) {
tailTask->next=task;
tailTask=task;
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}
if (task->pid!=0) {
serial_printf("Created task with PID %d.\n",task->pid);
}
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return task;
}
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int* tasking_get_errno_address() {
return &(currentTask->errno);
}
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char isPrivleged(uint32_t pid) {
for (Task* task=headTask;task!=NULL;task=task->next) {
if (task->pid==pid) {
return task->priv;
}
}
return 0;
}
Task* tasking_createTask(void* eip) {
return tasking_createTaskCr3KmodeParam(eip,paging_new_address_space(),0,0,0,0,0);
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}
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void tasking_yield(registers_t registers) {
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Task* task=currentTask->next;
if (!task) {
task=headTask;
}
serial_printf("Yielding to PID %d.\n",task->pid);
load_smap(task->cr3);
switch_to_task(task);
}
void tasking_yieldToPID(uint32_t pid) {
Task* task=tasks[pid];
if (!task) {
serial_printf("PID %d does not exist.\n",pid);
return;
}
serial_printf("Yielding to PID %d.\n",task->pid);
load_smap(task->cr3);
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switch_to_task(task);
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}
uint32_t getPID() {
return currentTask->pid;
}