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#include <kernel/memory/paging.h>
#include <kernel/tasks/task.h>
#include <kernel/memory/alloc.h>
#include <kernel/lib/lib.h>
#include <kernel/gdt/gdt.h>
#include <kernel/system.h>
task_t *current_task;
task_t *ready_queue;
extern uint32_t read_eip();
uint32_t next_pid = 1;
void tasking_install()
{
asm ("cli");
move_stack((void *) 0xE0000000, 0x2000);
current_task = ready_queue = (task_t *) kmalloc(sizeof(task_t));
current_task->id = (int) next_pid++;
current_task->esp = 0;
current_task->ebp = 0;
current_task->eip = 0;
current_task->page_directory = current_page_directory;
current_task->next = 0;
current_task->kernel_stack = kmalloc(KERNEL_STACK_SIZE);
vga_log("Installed Tasking");
asm ("sti");
}
void move_stack(void *new_stack_start, uint32_t size)
{
for (uint32_t i = (uint32_t) new_stack_start;
i >= ((uint32_t) new_stack_start - size);
i -= 0x1000) {
// paging_alloc_frame(paging_get_page(i, 1, current_page_directory), 0, 1);
}
uint32_t pd_addr;
asm volatile ("mov %%cr3, %0" : "=r" (pd_addr));
asm volatile ("mov %0, %%cr3" : : "r" (pd_addr));
uint32_t old_stack_pointer; asm volatile ("mov %%esp, %0" : "=r" (old_stack_pointer));
uint32_t old_base_pointer; asm volatile ("mov %%ebp, %0" : "=r" (old_base_pointer));
uint32_t offset = (uint32_t) new_stack_start - initial_esp;
uint32_t new_stack_pointer = old_stack_pointer + offset;
uint32_t new_base_pointer = old_base_pointer + offset;
memcpy((void *) new_stack_pointer, (void *) old_stack_pointer, initial_esp - old_stack_pointer);
for (uint32_t i = (uint32_t) new_stack_start; i > (uint32_t) new_stack_start - size; i -= 4) {
uint32_t tmp = *(uint32_t *) i;
if ((old_stack_pointer < tmp) && (tmp < initial_esp)) {
tmp = tmp + offset;
uint32_t *tmp2 = (uint32_t *) i;
*tmp2 = tmp;
}
}
asm volatile ("mov %0, %%esp" : : "r" (new_stack_pointer));
asm volatile ("mov %0, %%ebp" : : "r" (new_base_pointer));
}
extern void perform_task_switch(uint32_t, uint32_t, uint32_t, uint32_t);
void switch_task()
{
if (!current_task)
return;
uint32_t esp, ebp, eip;
asm volatile ("mov %%esp, %0" : "=r"(esp));
asm volatile ("mov %%ebp, %0" : "=r"(ebp));
eip = read_eip();
if (eip == 0x12345)
return;
current_task->eip = eip;
current_task->esp = esp;
current_task->ebp = ebp;
current_task = current_task->next;
if (!current_task) current_task = ready_queue;
eip = current_task->eip;
esp = current_task->esp;
ebp = current_task->ebp;
current_page_directory = current_task->page_directory;
set_kernel_stack((uintptr_t) (current_task->kernel_stack + KERNEL_STACK_SIZE));
paging_switch_directory((int) current_page_directory);
perform_task_switch(eip, (uint32_t) current_page_directory, ebp, esp);
}
int fork()
{
asm ("cli");
task_t *parent_task = (task_t *) current_task;
uint32_t *directory = 0;//paging_clone_directory(current_page_directory);
task_t *new_task = (task_t *) kmalloc(sizeof(task_t));
new_task->id = (int) next_pid++;
new_task->esp = new_task->ebp = 0;
new_task->eip = 0;
new_task->page_directory = directory;
current_task->kernel_stack = kmalloc(KERNEL_STACK_SIZE);
new_task->next = 0;
task_t *tmp_task = (task_t *) ready_queue;
while (tmp_task->next)
tmp_task = tmp_task->next;
tmp_task->next = new_task;
uint32_t eip = read_eip();
if (current_task == parent_task) {
uint32_t esp; asm volatile ("mov %%esp, %0" : "=r"(esp));
uint32_t ebp; asm volatile ("mov %%ebp, %0" : "=r"(ebp));
new_task->esp = esp;
new_task->ebp = ebp;
new_task->eip = eip;
asm volatile ("sti");
return new_task->id;
} else {
return 0;
}
}
int getpid()
{
return current_task->id;
}
void exec(uint32_t binary)
{
set_kernel_stack((uintptr_t) (current_task->kernel_stack + KERNEL_STACK_SIZE));
info("Switching to user mode...");
asm volatile ("\
cli; \
mov $0x23, %%ax; \
mov %%ax, %%ds; \
mov %%ax, %%es; \
mov %%ax, %%fs; \
mov %%ax, %%gs; \
mov %%esp, %%eax; \
pushl $0x23; \
pushl %%esp; \
pushf; \
pushl $0x1B; \
push $1f; \
iret; \
1: \
" : : "r" (binary));
// syscall_write("test");
}
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