1 files changed, 132 insertions, 0 deletions
diff --git a/src/loader/interrupt.c b/src/loader/interrupt.c
new file mode 100644
index 0000000..e05b4e0
--- /dev/null
+++ b/src/loader/interrupt.c
@@ -0,0 +1,132 @@
+// MIT License, Copyright (c) 2021 Marvin Borner
+
+#include <interrupt.h>
+#include <log.h>
+#include <pic.h>
+#include <panic.h>
+
+/**
+ * IDT
+ */
+
+extern u32 interrupt_table[];
+static struct idt_entry idt_entries[256] = { 0 };
+REAL static struct idt_ptr idt = { .size = sizeof(idt_entries) - 1, .base = idt_entries };
+
+void idt_install(void)
+{
+	for (u8 i = 0; i < 3; i++)
+		idt_entries[i] = IDT_ENTRY(interrupt_table[i], 0x18, INTERRUPT_GATE);
+
+	idt_entries[3] = IDT_ENTRY(interrupt_table[3], 0x18, INTERRUPT_TRAP);
+	idt_entries[4] = IDT_ENTRY(interrupt_table[4], 0x18, INTERRUPT_TRAP);
+
+	for (u8 i = 5; i < 48; i++)
+		idt_entries[i] = IDT_ENTRY(interrupt_table[i], 0x18, INTERRUPT_GATE);
+
+	// Load table
+	__asm__ volatile("lidt %0" : : "m"(idt) : "memory");
+}
+
+/**
+ * Exception (trap) handling
+ */
+
+static const char *interrupt_trap_names[32] = {
+	"Division By Zero",
+	"Debug",
+	"Non Maskable Interrupt",
+	"Breakpoint",
+	"Into Detected Overflow",
+	"Out of Bounds",
+	"Invalid Opcode",
+	"No Coprocessor",
+
+	"Double Fault",
+	"Coprocessor Segment Overrun",
+	"Bad TSS",
+	"Segment Not Present",
+	"Stack Fault",
+	"General Protection Fault",
+	"Page Fault",
+	"Unknown Interrupt",
+
+	"Coprocessor Fault",
+	"Alignment Check",
+	"Machine Check",
+	"Reserved",
+	"Reserved",
+	"Reserved",
+	"Reserved",
+	"Reserved",
+
+	"Reserved",
+	"Reserved",
+	"Reserved",
+	"Reserved",
+	"Reserved",
+	"Reserved",
+	"Reserved",
+	"Reserved",
+};
+
+static void interrupt_trap_handler(struct interrupt_frame *frame)
+{
+	static u8 faulting = 0;
+	faulting++;
+
+	if (faulting == 2) {
+		// Fall back to serial driver
+		serial_print("Double fault, halting immediatly\n");
+		while (1)
+			__asm__ volatile("cli\nhlt");
+	}
+
+	log("%s Exception (code %x) at 0x%x!\n", interrupt_trap_names[frame->interrupt_no], frame->err_code,
+	    frame->eip);
+
+	while (1)
+		__asm__ volatile("cli\nhlt");
+}
+
+/**
+ * Event handling
+ */
+
+static void (*interrupt_event_handlers[16])(void) = { 0 };
+
+void interrupt_event_handler_add(u32 interrupt_no, void (*handler)(void))
+{
+	assert(interrupt_no < COUNT(interrupt_event_handlers));
+	interrupt_event_handlers[interrupt_no] = handler;
+}
+
+static u32 interrupt_event_handler(struct interrupt_frame *frame)
+{
+	u32 interrupt_no = frame->interrupt_no - 32;
+	assert(interrupt_no < COUNT(interrupt_event_handlers));
+	void (*handler)(void) = interrupt_event_handlers[interrupt_no];
+	if (handler)
+		handler();
+
+	return (u32)frame;
+}
+
+/**
+ * Universal handler
+ */
+
+u32 interrupt_handler(u32 esp);
+u32 interrupt_handler(u32 esp)
+{
+	struct interrupt_frame *frame = (struct interrupt_frame *)esp;
+	if (frame->interrupt_no < 32)
+		interrupt_trap_handler(frame);
+	else if (frame->interrupt_no < 48)
+		esp = interrupt_event_handler(frame);
+	else
+		panic("Unknown interrupt\n");
+
+	pic_ack(frame->interrupt_no);
+	return esp;
+}