Getting closer!

3 files changed, 42 insertions, 14 deletions

diff --git a/kernel/features/load.c b/kernel/features/load.c
index 610abf8..4b3f8ea 100644
--- a/kernel/features/load.c
+++ b/kernel/features/load.c
@@ -8,16 +8,15 @@
 
 #define PROC_STACK_SIZE 0x4000
 
-void proc_load(struct proc *proc, void *data)
+void proc_load(struct proc *proc, u32 entry)
 {
 	u32 stack;
 	memory_alloc(proc->page_dir, PROC_STACK_SIZE, MEMORY_CLEAR, &stack);
-	u32 ptr = stack + PROC_STACK_SIZE - 1;
 
-	proc->regs.ebp = (u32)ptr;
-	proc->regs.useresp = (u32)ptr;
-	proc->regs.eip = (u32)data;
-	proc->entry = (u32)data;
+	proc->regs.ebp = stack;
+	proc->regs.useresp = stack;
+	proc->regs.eip = entry;
+	proc->entry = entry;
 }
 
 int bin_load(const char *path, struct proc *proc)
@@ -30,7 +29,7 @@ int bin_load(const char *path, struct proc *proc)
 		return 1;
 
 	strcpy(proc->name, path);
-	proc_load(proc, (void *)data);
+	proc_load(proc, data);
 
 	return 0;
 }
diff --git a/kernel/features/mm.c b/kernel/features/mm.c
index ccc2727..ad70685 100644
--- a/kernel/features/mm.c
+++ b/kernel/features/mm.c
@@ -25,6 +25,7 @@ void paging_enable(void)
 
 void paging_switch_dir(u32 dir)
 {
+	assert(dir);
 	cr3_set(dir);
 }
 
@@ -418,7 +419,7 @@ void memory_initialize(struct mem_info *mem_info)
 	memory_map_identity(&kernel_dir, memory_range_around_address(HEAP_START, HEAP_INIT_SIZE),
 			    MEMORY_NONE);
 
-	// TODO: Map something, idk? Triple fault prevention?
+	// TODO: Triple fault prevention? Probably bootloader stuff or something
 	memory_map_identity(&kernel_dir, memory_range_around_address(0x7000, 0x1000), MEMORY_NONE);
 
 	// Unmap NULL byte/page
@@ -429,8 +430,37 @@ void memory_initialize(struct mem_info *mem_info)
 	paging_enable();
 }
 
+static void page_fault(struct regs *r)
+{
+	// Check error code
+	const char *type = (r->err_code & 4) ? "present" : "non-present";
+	const char *operation = (r->err_code & 2) ? "write" : "read";
+	const char *super = (r->err_code & 1) ? "User" : "Super";
+
+	// Check cr2 address
+	u32 vaddr;
+	__asm__ volatile("movl %%cr2, %%eax" : "=a"(vaddr));
+	struct proc *proc = proc_current();
+	struct page_dir *dir = NULL;
+	if (proc && proc->page_dir) {
+		dir = proc->page_dir;
+		printf("Stack is at %x, entry at %x\n", virtual_to_physical(dir, proc->regs.ebp),
+		       virtual_to_physical(dir, proc->entry));
+	} else {
+		dir = &kernel_dir;
+	}
+	u32 paddr = virtual_to_physical(dir, vaddr);
+
+	// Print!
+	printf("%s process tried to %s a %s page at [vaddr=%x; paddr=%x]\n", super, operation, type,
+	       vaddr, paddr);
+
+	isr_panic(r);
+}
+
 void paging_install(struct mem_info *mem_info)
 {
 	memory_initialize(mem_info);
 	heap_init(HEAP_START);
+	isr_install_handler(14, page_fault);
 }
diff --git a/kernel/features/proc.c b/kernel/features/proc.c
index bbe675e..43cedb6 100644
--- a/kernel/features/proc.c
+++ b/kernel/features/proc.c
@@ -20,7 +20,7 @@ struct list *proc_list = NULL;
 struct node *idle_proc = NULL;
 struct node *current = NULL;
 
-// TODO: Use less memcpy and only copy relevant registers
+// TODO: Use less memcpy and only copy relevant registers (rewrite for efficiency argh)
 // TODO: 20 priority queues (https://www.kernel.org/doc/html/latest/scheduler/sched-nice-design.html)
 void scheduler(struct regs *regs)
 {
@@ -57,8 +57,8 @@ void scheduler(struct regs *regs)
 		}
 	}
 
-	memcpy(regs, &((struct proc *)current->data)->regs, sizeof(struct regs));
 	memory_dir_switch(((struct proc *)current->data)->page_dir);
+	memcpy(regs, &((struct proc *)current->data)->regs, sizeof(struct regs));
 
 	if (regs->cs != GDT_USER_CODE_OFFSET) {
 		regs->gs = GDT_USER_DATA_OFFSET;
@@ -473,8 +473,7 @@ void proc_init(void)
 
 	// Idle proc
 	struct proc *kernel_proc = proc_make(PROC_PRIV_NONE);
-	void (*func)(void) = kernel_idle;
-	proc_load(kernel_proc, *(void **)&func);
+	proc_load(kernel_proc, (u32)kernel_idle);
 	strcpy(kernel_proc->name, "idle");
 	kernel_proc->state = PROC_SLEEPING;
 	idle_proc = list_add(proc_list, kernel_proc);
@@ -494,11 +493,11 @@ void proc_init(void)
 	argv[2] = NULL;
 
 	((u32 *)_esp)[0] = argc; // First argument (argc)
-	((u32 *)_esp)[1] = (u32)argv; // Second argument (argv)
+	((u32 *)_esp)[-1] = (u32)argv; // Second argument (argv)
 
 	printf("Jumping to userspace!\n");
-	proc_jump_userspace();
 	memory_dir_switch(((struct proc *)new->data)->page_dir);
+	proc_jump_userspace();
 	while (1) {
 	};
 }