Fix nasty task switching bu

6 files changed, 23 insertions, 15 deletions

diff --git a/gdb_cmd b/gdb_cmd
index e1480eb..994e6c0 100644
--- a/gdb_cmd
+++ b/gdb_cmd
@@ -1,2 +1,3 @@
 target remote localhost:1234
-break l0/sys.c:panic_do
+symbol-file build/kernel.bin
+break core/sys.c:panic_do
diff --git a/src/kernel/core/context_switch.s b/src/kernel/core/context_switch.s
index b8f6bb8..e81fa56 100644
--- a/src/kernel/core/context_switch.s
+++ b/src/kernel/core/context_switch.s
@@ -4,13 +4,15 @@
 [GLOBAL save_context_and_enter_scheduler]
 ; void save_context_and_enter_scheduler(struct saved_context *ctx);
 save_context_and_enter_scheduler:
+	push ebp				; save stack frame for debugging
+	mov ebp, esp
 	pushf					; push flags
 	cli
 	pusha					; push general registers
 	mov eax, cr3			; push CR3
 	push eax
 
-	mov eax, [esp+44]		; get address of saved_context structure
+	mov eax, [ebp+8]		; get address of saved_context structure
 	mov [eax], esp			; save esp
 	mov dword [eax+4], resume_saved_context		; save eip
 
@@ -22,12 +24,15 @@ resume_saved_context:
 	mov cr3, eax
 	popa			; restore general registers
 	popf			; restore flags
+	pop ebp
 	ret
 
 
 [GLOBAL resume_context]
 resume_context:
-	mov eax, [esp+4]		; get address of saved context
+	push ebp
+	mov ebp, esp
+	mov eax, [ebp+8]		; get address of saved context
 	mov esp, [eax]			; resume esp
 	mov ecx, [eax+4]		; jump to specified eip
 	jmp ecx
diff --git a/src/kernel/core/frame.c b/src/kernel/core/frame.c
index e74f9ad..7cc9bca 100644
--- a/src/kernel/core/frame.c
+++ b/src/kernel/core/frame.c
@@ -16,8 +16,9 @@ static uint32_t begin_search_at;
 void frame_init_allocator(size_t total_ram, void** kernel_data_end) {
 	nframes = PAGE_ID(total_ram);
 
+	// Statically allocate space after kernel data end
 	frame_bitset = (uint32_t*)ALIGN4_UP((size_t)*kernel_data_end);
-	*kernel_data_end = (void*)frame_bitset + ALIGN4_UP(nframes / 8);
+	*kernel_data_end = (void*)((size_t)frame_bitset + ALIGN4_UP(nframes / 8));
 
 	for (size_t i = 0; i < ALIGN4_UP(nframes / 8)/4; i++)
 		frame_bitset[i] = 0;
diff --git a/src/kernel/core/interrupt.s b/src/kernel/core/interrupt.s
index 8fb71e8..084d7c9 100644
--- a/src/kernel/core/interrupt.s
+++ b/src/kernel/core/interrupt.s
@@ -2,6 +2,7 @@
 
 %macro COMMONSTUB 1
 [EXTERN idt_%1_handler]
+[GLOBAL %1_common_stub]		; For debugging
 %1_common_stub:
 
 	pusha                    ; Pushes edi,esi,ebp,esp,ebx,edx,ecx,eax
diff --git a/src/kernel/core/sys.c b/src/kernel/core/sys.c
index e852274..8cc1407 100644
--- a/src/kernel/core/sys.c
+++ b/src/kernel/core/sys.c
@@ -80,7 +80,7 @@ void kernel_stacktrace(uint32_t ebp, uint32_t eip) {
 			sym = btree_lower(kernel_symbol_map, (void*)eip, &fn_ptr);
 		}
 
-		dbg_printf("| 0x%p	EIP: 0x%p  %s  +0x%p\n", ebp, eip, sym, ((void*)eip - fn_ptr));
+		dbg_printf("| 0x%p	EIP: 0x%p  %s  +%d\n", ebp, eip, sym, ((void*)eip - fn_ptr));
 
 		uint32_t *d = (uint32_t*)ebp;
 		ebp = d[0];
diff --git a/src/kernel/core/thread.c b/src/kernel/core/thread.c
index 37226ae..342cead 100644
--- a/src/kernel/core/thread.c
+++ b/src/kernel/core/thread.c
@@ -127,19 +127,22 @@ void run_scheduler() {
 		if (current_thread->proc) current_thread->proc->last_ran = current_thread->last_ran;
 		enqueue_thread(current_thread, true);
 	}
-	current_thread = dequeue_thread();
+	current_thread = 0;
 
-	if (current_thread != prev_thread && SPAM_CONTEXT_SWITCH) dbg_printf("[0x%p]\n", current_thread);
+	thread_t *next_thread = dequeue_thread();
 
-	if (current_thread != 0) {
-		thread_t *ptr = current_thread;
-		prng_add_entropy((uint8_t*)&ptr, sizeof(ptr));
+	if (next_thread != prev_thread && SPAM_CONTEXT_SWITCH) dbg_printf("[0x%p]\n", next_thread);
 
-		set_kernel_stack(current_thread->stack_region->addr + current_thread->stack_region->size);
+	if (next_thread != 0) {
+		prng_add_entropy((uint8_t*)&next_thread, sizeof(next_thread));
+
+		set_kernel_stack(next_thread->stack_region->addr + next_thread->stack_region->size);
+
+		current_thread = next_thread;
 		resume_context(&current_thread->ctx);
 	} else {
 		// Wait for an IRQ
-		asm volatile("sti; hlt");
+		asm volatile("sti; hlt; cli");
 		// At this point an IRQ has happenned
 		// and has been processed. Loop around. 
 		run_scheduler();
@@ -247,9 +250,6 @@ void threading_setup(entry_t cont, void* arg) {
 	ASSERT(t != 0);
 
 	start_thread(t);
-
-	exit_critical(CL_USER);
-
 	run_scheduler();	// never returns
 	ASSERT(false);
 }