u7 docu

boards/portux/drivers/mmu.c

@@ -36,6 +36,7 @@ void release_addsp_slot(addsp_queue* q, int slt) {
 	q->available++;
 }
 
+// this is needed by the process mgmt, but we can't turn on the mmu before process mgmt
 void init_mmu_mgmt() {
     init_addsp_queue(&addsp_q);
 }
@@ -63,17 +64,16 @@ void init_first_level_pagetable(uint address_space_id) {
         address_spaces[address_space_id].desc[i] = (AP_NONE_NONE << 10) | 0b10;
     for (uint i = (UNDEF_MEMORY2 >> 20); i < 249; ++i)
         address_spaces[address_space_id].desc[i] = (AP_NONE_NONE << 10) | 0b10;
-    // make userland acessible by users
+    // make usercode acessible by users
     uint userland_desc = EXTERNAL_SRAM >> 20;
     address_spaces[address_space_id].desc[userland_desc] = (userland_desc << 20) | (AP_RW_R << 10) | 0b10;
-    /*for (uint i = 0; i < 63; ++i) {
-        address_spaces[address_space_id].desc[userland_desc + 1 + i] |= (AP_RW_RW << 10);
-    }*/
-    // modify the mapping to switch 1MB of sram with 1MB of undef memory
-    //address_spaces[address_space_id].desc[(EXTERNAL_SRAM + 17*MEGABYTE) >> 20] = (UNDEF_MEMORY1) | (AP_RW_RW << 10) | 0b10;
-    //address_spaces[address_space_id].desc[(UNDEF_MEMORY1) >> 20] = (EXTERNAL_SRAM + 17*MEGABYTE) | (AP_RW_RW << 10) | 0b10;
+
 }
 
+/**
+ * Grants access to a section of memory of size size located at dest in physical address space
+ * and mapped at address in logical address space address_space_id.
+ */
 int set_ap(uint address_space_id, void* address, uint size, void* dest, uint ap) {
     if (size != MEGABYTE)
         return -1;

boards/portux/startup.c

@@ -78,7 +78,6 @@ void c_entry(void) {
 	demo_t.start = &u7_demo;
 	new_thread("demo", &demo_t);
 
-	
 	/* interrupt tst loop*/
 	while (42) {
 		asm volatile("nop":::);

kernel/process_mgmt.c

@@ -67,8 +67,11 @@ void idle() {
 }
 
 void exit(u32* hw_context) {
-	// Don't call tis directly frem kernel... Why would you?
-	// if (current.open_handles == 0)
+	// Don't call this directly from kernel... Why would you?
+
+	// we can only release a process if it has no children,
+	// as it might be owner of the address space.
+	// we can only release the address_space if we're actually its owner.
 	if (processes[current].children > 0) {
 		processes[current].state = ZOMBIE;
 	} else {
@@ -137,7 +140,9 @@ int new_thread(char* name, init_thread_state_args* args) {
 	return internal_new_thread_finalizer(name, id);
 }
 
+// this one is not yet updated for the children + address-space thing.
 int new_thread_raw(char* name, cpu_context* init_state, bool may_be_sys) {
+	return -1;
 	if (!cpu_context_validate(init_state, may_be_sys)) return -2;
 	int id = get_tcb_slot(&tcbq);
 	if (id < 0) return -1;
@@ -158,12 +163,14 @@ void thread_swap_callback(u32* context) {
 			break;
 
 		// get your chainsaw and your shotgun cause we're going on a zombie-hunt
+		// we haven't upgraded to the recursive shotgun yet.
 		if (processes[next].state == ZOMBIE && processes[next].children == 0) {
 			release_tcb_slot(&tcbq, processes[next].id);
-			release_address_space(processes[next].address_space);
 			processes[next].state = DEAD;
 			if (processes[next].parent)
 				processes[processes[next].parent].children -= 1;
+			else
+				release_address_space(processes[next].address_space);
 			printf("BOOM! -> %x\n", processes[next].id);
 		}
 	}