diff options
Diffstat (limited to 'src/kernel/tasks/task.c')
| -rw-r--r-- | src/kernel/tasks/task.c | 168 |
1 files changed, 168 insertions, 0 deletions
diff --git a/src/kernel/tasks/task.c b/src/kernel/tasks/task.c new file mode 100644 index 0000000..e6caf9a --- /dev/null +++ b/src/kernel/tasks/task.c @@ -0,0 +1,168 @@ +#include <kernel/memory/paging.h> +#include <kernel/tasks/task.h> +#include <kernel/memory/kheap.h> +#include <kernel/lib/lib.h> +#include <kernel/gdt/gdt.h> +#include <kernel/system.h> + +volatile task_t *current_task; +volatile task_t *ready_queue; + +extern page_directory_t *kernel_directory; +extern page_directory_t *current_directory; + +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 = current_task->ebp = 0; + current_task->eip = 0; + current_task->page_directory = current_directory; + current_task->next = 0; + current_task->kernel_stack = kmalloc_a(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_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_directory = current_task->page_directory; + + set_kernel_stack(current_task->kernel_stack + KERNEL_STACK_SIZE); + + perform_task_switch(eip, current_directory->physicalAddr, ebp, esp); +} + +int fork() +{ + asm ("cli"); + + task_t *parent_task = (task_t *) current_task; + + page_directory_t *directory = paging_clone_directory(current_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_a(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 switch_to_usermode(uint32_t binary) +{ + set_kernel_stack(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 %0; \ + iret; \ + 1: \ + " : : "r" (binary)); +}
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