feat: added support for waiting on an irq

kernel/cpu/isr.c

@@ -10,6 +10,7 @@
 #include <drivers/ports.h>
 #include <libc/kprintf.h>
 #include <libk/libk.h>
+#include <tasks/task.h>
 
 #define PIC_END_OF_INTERRUPT 0x20
 
@@ -142,6 +143,9 @@ void irq_handler(isr_registers_t r) {
     if (r.int_no >= 40) port_byte_out(PORT_PIC_SLAVE_COMMAND, PIC_END_OF_INTERRUPT); /* slave */
     port_byte_out(PORT_PIC_MASTER_COMMAND, PIC_END_OF_INTERRUPT); /* master */
 
+    if (r.int_no >= IRQ0 && r.int_no < IRQ15) {
+        task_notify_irq(r.int_no - IRQ0);
+    }
     /* Handle the interrupt in a more modular way */
     if (interrupt_handlers[r.int_no] != NULL) {
         isr_t handler = interrupt_handlers[r.int_no];

kernel/cpu/syscall_handler.c

@@ -14,6 +14,8 @@ void syscall_handle(isr_registers_t *registers) {
         case SYSCALL_YIELD_JOB:
             task_switch_next();
             break;
+        case SYSCALL_YIELD_IRQ:
+            task_wait_irq(registers->ebx);
         default:
             break;
     }

kernel/drivers/keyboard.c

@@ -8,6 +8,7 @@
 #include <libc/ringqueue.h>
 #include <libk/libk.h>
 #include <mem/malloc.h>
+#include <libk/syscall.h>
 
 
 const char scancode_map_lowercase[] = {
@@ -63,7 +64,8 @@ char getc() {
 KeyEvent *get_next_event() {
     KeyEvent *target = malloc(sizeof(KeyEvent));
     if (!ring_buffer_get(keyboard_event_buffer, target)) {
-        k_wait_for_interrupt();
+        syscall_yield_irq(1 << 1);
+//        k_wait_for_interrupt();
         free(target);
         return NULL;
     }

kernel/kernel.c

@@ -78,6 +78,7 @@ void noreturn kmain(multiboot_info_t *multiboot_info) {
 
     printf("Booted successfully v%d.%d.%d\n", version_major, version_minor, version_patch);
 
+    task_init();
     task_spawn(main_loop, NULL);
     syscall_start_scheduler();
 }

kernel/libk/syscall.c

@@ -12,11 +12,21 @@ void syscall1(uint32_t arg1) {
     : "a"(arg1));
 }
 
-void syscall_yield_job() {
-    syscall1(SYSCALL_YIELD_JOB);
+void syscall2(uint32_t arg1, uint32_t arg2) {
+    __asm__("int $0x80"
+    :
+    : "a"(arg1), "b"(arg2));
 }
 
 void noreturn syscall_start_scheduler() {
     syscall1(SYSCALL_START_SCHEDULER);
     while (1) { __asm__("hlt"); };
-}
+}
+
+void syscall_yield_job() {
+    syscall1(SYSCALL_YIELD_JOB);
+}
+
+void syscall_yield_irq(uint16_t irq) {
+    syscall2(SYSCALL_YIELD_IRQ, irq );
+}

kernel/libk/syscall.h

@@ -4,14 +4,17 @@
 
 #ifndef NEW_KERNEL_SYSCALL_H
 #define NEW_KERNEL_SYSCALL_H
-
+#include <types.h>
 #include <attributes.h>
 
 #define SYSCALL_START_SCHEDULER 0x01
 #define SYSCALL_YIELD_JOB       0x02
-
-void syscall_yield_job();
+#define SYSCALL_YIELD_IRQ       0x03
 
 void noreturn syscall_start_scheduler();
 
+void syscall_yield_job();
+
+void syscall_yield_irq(uint16_t irq);
+
 #endif //NEW_KERNEL_SYSCALL_H

kernel/tasks/task.c

@@ -13,15 +13,24 @@
 
 #define stack_end(task) ((task)->stack + ((task)->stack_page_count * PAGE_SIZE))
 
+#define TASK_STATE_UNKNOWN      (0)
+#define TASK_STATE_RUNNABLE     (1 << 0)
+#define TASK_STATE_RUNNING      (1 << 1)
+#define TASK_STATE_WAIT_IRQ     (1 << 2)
+
+#define TASK_STATE_ERROR        (1 << 7)
+
+
 typedef struct task {
     bool present: 1;
-    uint8_t wait_irq: 4;
+    uint8_t state;
+    uint16_t wait_irq;
 
     uint32_t tid;
 
     struct task *next;
 
-    void* stack;
+    void *stack;
     uint32_t stack_page_count;
 
     task_registers_t *task_registers;
@@ -37,15 +46,20 @@ typedef struct {
 
 bool task_locked = false;
 
+task_t *idle_task = NULL;
 task_t *first_task = NULL;
 task_t *last_task = NULL;
 task_t *current_task = NULL;
 
 uint32_t last_tid = 0;
 
-extern switch_task(task_registers_t**, task_registers_t*);
+extern switch_task(task_registers_t
+**, task_registers_t*);
+
 extern cdecl noreturn void __task_entry_point();
+
 extern noreturn void __task_entry_point_inner();
+
 // explicit cdecl calling convention
 void cdecl noreturn task_entry_point(task_entrypoint entrypoint, void *entry_data) {
     entrypoint(entry_data);
@@ -61,6 +75,28 @@ void task_lock_free() {
     task_locked = false;
 }
 
+void noreturn task_idle(void *data) {
+    while (true) __asm__("hlt");
+}
+
+void task_notify_irq(uint8_t irq_no) {
+    uint16_t irq__bit = 1 << irq_no;
+    task_t *t = first_task;
+    while (t != NULL) {
+        if (t->state == TASK_STATE_WAIT_IRQ && (t->wait_irq & irq__bit) != 0) {
+            t->wait_irq = 0;
+            t->state = TASK_STATE_RUNNABLE;
+        }
+        t = t->next;
+    }
+}
+
+void task_wait_irq(uint16_t irq_bits) {
+    current_task->wait_irq = irq_bits;
+    current_task->state = TASK_STATE_WAIT_IRQ;
+    task_switch_next();
+}
+
 void task_switch_next_inner(task_t *next_task) {
     if (task_locked) {
         return; // don't switch while the task is locked
@@ -70,6 +106,10 @@ void task_switch_next_inner(task_t *next_task) {
     }
     task_t *previous_task = current_task;
     current_task = next_task;
+    if (previous_task->state == TASK_STATE_RUNNING) {
+        previous_task->state = TASK_STATE_RUNNABLE;
+    }
+    current_task->state = TASK_STATE_RUNNING;
     // switch task
     switch_task(previous_task == NULL ? NULL : &previous_task->task_registers, current_task->task_registers);
 }
@@ -78,34 +118,53 @@ void task_start_first() {
     task_switch_next_inner(first_task);
 }
 
+task_t *task_first_runnable() {
+    task_t *next_task = current_task;
+    bool looped = false;
+    if (next_task == idle_task || next_task->next == NULL) {
+        looped = true;
+        next_task = first_task;
+    } else {
+        next_task = current_task->next;
+    }
+    do {
+        if (!looped && next_task == NULL) {
+            looped = true;
+            next_task = first_task;
+        }
+        if (next_task == NULL) {
+            break;
+        }
+        if (next_task->state == TASK_STATE_RUNNABLE) {
+            return next_task;
+        }
+        next_task = next_task->next;
+    } while (next_task != current_task);
+    if (current_task->state == TASK_STATE_RUNNING)
+        return current_task;
+    return idle_task;
+}
+
 void task_switch_next() {
     if (current_task == NULL) {
         return;
     }
-    task_switch_next_inner(current_task->next == NULL ? first_task : current_task->next);
+    task_switch_next_inner(task_first_runnable());
 }
 
-uint32_t task_spawn(task_entrypoint entrypoint, void *entry_data) {
+task_t *task_create(task_entrypoint entrypoint, void *entry_data) {
     task_t *new_task = malloc(sizeof(task_t));
     memset((uint8_t *) new_task, 0, sizeof(task_t));
     new_task->tid = last_tid++;
+    new_task->state = TASK_STATE_RUNNABLE;
 
     new_task->stack = pmm_get_pages(16);
     new_task->stack_page_count = 16;
     // todo check for null
 
-
-    if (first_task == NULL) {
-        // first task
-        first_task = new_task;
-    } else {
-        last_task->next = new_task;
-    }
-    last_task = new_task;
-
     // prepare stack
     // cdecl format
-    task_stack_start* stack = (task_stack_start *) (stack_end(new_task) - sizeof(task_stack_start));
+    task_stack_start *stack = (task_stack_start *) (stack_end(new_task) - sizeof(task_stack_start));
     memset((uint8_t *) stack, 0, sizeof(task_stack_start));
     // setup isr return frame
     stack->isr_registers.cs = 0x08; // todo proper gdt setup
@@ -124,6 +183,23 @@ uint32_t task_spawn(task_entrypoint entrypoint, void *entry_data) {
     new_task->task_registers = &stack->task_registers;
 
     new_task->present = true;
+    return new_task;
+
+}
+
+void task_init() {
+    idle_task = task_create(task_idle, NULL);
+}
+
+uint32_t task_spawn(task_entrypoint entrypoint, void *entry_data) {
+    task_t *new_task = task_create(entrypoint, entry_data);
+    if (first_task == NULL) {
+        // first task
+        first_task = new_task;
+    } else {
+        last_task->next = new_task;
+    }
+    last_task = new_task;
     return new_task->tid;
 }
 

kernel/tasks/task.h

@@ -9,6 +9,12 @@
 
 typedef void (*task_entrypoint)(void *entry_data);
 
+void task_notify_irq(uint8_t irq_no);
+
+void task_wait_irq(uint16_t irq_bits);
+
+void task_init();
+
 void task_start_first();
 
 void task_switch_next();