#include "memory/pagefault.h"

#include "arch/core.h"
#include "arch/core_interrupt.h"
#include "arch/idt.h"
#include "debug/output.h"
#include "memory/config.h"

namespace PageFault {

union ErrorCode {
	uint32_t value;
	struct {
		uint32_t present : 1;	   ///< was the page present?
		uint32_t write : 1;		   ///< was the access a write?
		uint32_t usermode : 1;	   ///< was it in user mode?
		uint32_t reserved : 1;	   ///< reserved bit violation
		uint32_t instruction : 1;  ///< was it caused by instruction fetch?
		uint32_t : 0;
	} __attribute__((packed));

	explicit ErrorCode(uint32_t value) : value(value) {}
};

assert_size(ErrorCode, 4);

[[gnu::interrupt]] static void pagefault_handler(InterruptContext *context,
												 uint64_t err) {
	PageFault::ErrorCode error(err);
	// Get the faulting address
	uintptr_t virt = 0;
	asm volatile("mov %%cr2, %0" : "=r"(virt));
	DBG << "Page fault at " << hex << virt << dec << endl;

	// show page fault message
	DBG << "PAGEFAULT: " << hex << virt << ":" << dec << error.present
		<< error.write << error.usermode << error.reserved << error.instruction
		<< " @ " << hex << context->ip << endl;

	Core::die();
}

void init() {
	IDT::set(Core::Interrupt::Vector::PAGE_FAULT,
			 IDT::InterruptDescriptor::ReturningWithError(pagefault_handler));
}

}  // namespace PageFault