Mercurial > lcfOS
annotate cos/kernel/task.c @ 34:8012221dd740
Fixes for uninitialized data. This causes problems on real machines
| author | windel |
|---|---|
| date | Mon, 16 Jan 2012 13:46:06 +0100 |
| parents | 47b7df514243 |
| children | 91f91ff07ea8 |
| rev | line source |
|---|---|
| 28 | 1 /* Scheduler functions */ |
| 2 | |
| 25 | 3 #include "kernel.h" |
| 4 | |
| 5 // global variables: | |
| 6 uint64_t next_pid = 1; | |
| 7 task_t* ready_queue = 0; // Head of the queue of tasks. | |
| 8 task_t* current_task = 0; // Pointer to the currently running task. | |
| 9 | |
| 10 void initialize_tasking() | |
| 11 { | |
| 12 next_pid = 1; | |
| 13 } | |
| 14 | |
| 15 /* | |
| 16 Create a new task with some loaded program. | |
| 17 */ | |
| 18 void new_task() | |
| 19 { | |
| 20 task_t* newtask = (task_t*)kmalloc(sizeof(task_t)); | |
| 21 newtask->pid = next_pid++; | |
| 22 newtask->rip = 0; | |
| 23 newtask->next = 0; | |
| 24 | |
| 25 // Append the new task to the ready queue: | |
| 26 task_t* task = ready_queue; | |
| 27 while (task->next != 0) | |
| 28 { | |
| 29 task = task->next; | |
| 30 } | |
| 31 task->next = newtask; | |
| 32 } | |
| 33 | |
| 34 /* Fork function duplicates the process */ | |
| 35 void task_fork() | |
| 36 { | |
| 37 asm volatile("cli"); // Disable interrupts | |
| 38 task_t *parent_task = current_task; | |
| 39 | |
| 40 // Create new task: | |
| 41 task_t *new_task = (task_t*)kmalloc(sizeof(task_t)); | |
| 42 new_task->pid = next_pid++; | |
| 43 new_task->rsp = 0; | |
| 44 new_task->rbp = 0; | |
| 45 new_task->rip = 0; | |
| 46 new_task->next = 0; | |
| 47 | |
| 48 // Append to the queue: | |
| 49 task_t* tmp_task = ready_queue; | |
| 50 while (tmp_task->next != 0) | |
| 51 { | |
| 52 tmp_task = tmp_task->next; | |
| 53 } | |
| 54 tmp_task->next = new_task; | |
| 55 | |
| 56 uint64_t rip = read_rip(); | |
| 57 | |
| 58 if (current_task == parent_task) | |
| 59 { | |
| 60 uint64_t rbp, rsp; | |
| 61 asm volatile("mov %%rsp, %0" : "=r"(rsp)); | |
| 62 asm volatile("mov %%rbp, %0" : "=r"(rbp)); | |
| 63 new_task->rip = rip; | |
| 64 | |
| 65 asm volatile("sti"); | |
| 66 } | |
| 67 } | |
| 68 | |
| 69 /* | |
| 70 Scheduler function that switches tasks for multi tasking. | |
| 71 */ | |
| 72 void task_scheduler() | |
| 73 { | |
|
34
8012221dd740
Fixes for uninitialized data. This causes problems on real machines
windel
parents:
28
diff
changeset
|
74 return; |
|
8012221dd740
Fixes for uninitialized data. This causes problems on real machines
windel
parents:
28
diff
changeset
|
75 |
| 25 | 76 if (current_task == 0) |
| 77 { | |
| 78 return; | |
| 79 } | |
| 80 | |
| 81 uint64_t rbp, rsp, rip; | |
| 82 | |
| 83 rip = 0; | |
| 84 rsp = 0; | |
| 85 rbp = 0; | |
| 86 | |
| 87 current_task->rip = rip; // TODO | |
| 88 current_task->rsp = rsp; | |
| 89 current_task->rbp = rbp; | |
| 90 | |
| 91 // Select next task: | |
| 92 current_task = current_task->next; | |
| 93 if (current_task == 0) | |
| 94 { | |
| 95 current_task = ready_queue; | |
| 96 } | |
| 97 | |
| 98 // Set the rbp, rsp and rip registers: | |
| 99 rsp = current_task->rsp; | |
| 100 rbp = current_task->rbp; | |
| 101 } | |
| 102 |