/*
 * Copyright (c) 2020 Institute of Parallel And Distributed Systems (IPADS), Shanghai Jiao Tong University (SJTU)
 * OS-Lab-2020 (i.e., ChCore) is licensed under the Mulan PSL v1.
 * You can use this software according to the terms and conditions of the Mulan PSL v1.
 * You may obtain a copy of Mulan PSL v1 at:
 *   http://license.coscl.org.cn/MulanPSL
 *   THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, WITHOUT WARRANTIES OF ANY KIND, EITHER EXPRESS OR
 *   IMPLIED, INCLUDING BUT NOT LIMITED TO NON-INFRINGEMENT, MERCHANTABILITY OR FIT FOR A PARTICULAR
 *   PURPOSE.
 *   See the Mulan PSL v1 for more details.
 */

#include <common/types.h>
#include <process/thread.h>
#include <mm/vmspace.h>
#include <common/types.h>
#include <common/errno.h>

#include <common/kprint.h>
#include <common/util.h>
#include <common/macro.h>
#include <common/mm.h>
#include <common/kmalloc.h>

#include "esr.h"

static inline vaddr_t get_fault_addr()
{
	vaddr_t addr;
	asm volatile ("mrs %0, far_el1\n\t":"=r" (addr));
	return addr;
}

int handle_trans_fault(struct vmspace *vmspace, vaddr_t fault_addr);

void do_page_fault(u64 esr, u64 fault_ins_addr)
{
	vaddr_t fault_addr;
	int fsc;		// fault status code

	fault_addr = get_fault_addr();
	fsc = GET_ESR_EL1_FSC(esr);
	switch (fsc) {
	case DFSC_TRANS_FAULT_L0:
	case DFSC_TRANS_FAULT_L1:
	case DFSC_TRANS_FAULT_L2:
	case DFSC_TRANS_FAULT_L3:{
			int ret;

			ret =
			    handle_trans_fault(current_thread->vmspace,
					       fault_addr);
			if (ret != 0) {
				kinfo("pgfault at 0x%p failed\n", fault_addr);
				sys_exit(ret);
			}
			break;
		}
	default:
		kinfo("do_page_fault: fsc is unsupported (0x%b) now\n", fsc);
		BUG_ON(1);
		break;
	}
}

int handle_trans_fault(struct vmspace *vmspace, vaddr_t fault_addr)
{
	struct vmregion *vmr;
	struct pmobject *pmo;
	paddr_t pa;
	int ret;

	/*
	 * Lab3: your code here
	 * In this function, you should:
	 * 1. Get the vmregion of the fault_addr using find_vmr_for_va
	 * 2. If the pmo is not of type PMO_ANONYM, return -ENOMAPPING
	 * 3. Allocate one physical memory page for the PMO
	 * 4. Map the allocated address back to the page table
	 *
	 * NOTE: when any problem happened in this function, return
	 * -ENOMAPPING
	 * 
	 * NOTE: the real physical address of the PMO may not be
	 * continuous. In real chcore, all the physical pages of a PMO
	 * are recorded in a radix tree for easy management. Such code
	 * has been omitted in our lab for simplification.
	 */
	vmr = find_vmr_for_va(vmspace, fault_addr);
	if (vmr == NULL) {
        return -ENOMAPPING;
	}

	pmo = vmr->pmo;
	if (pmo->type != PMO_ANONYM) {
	    return -ENOMAPPING;
	}

	// 分配物理页
	pa = virt_to_phys(kmalloc(PAGE_SIZE));
	if ((void *) pa == NULL) {
        return -ENOMAPPING;
	}
	// 应该调用但是此处省略：commit_page_to_pmo(pmo, ..., pa);

	// 映射
    ret = map_range_in_pgtbl(vmspace->pgtbl, ROUND_DOWN(fault_addr, PAGE_SIZE), pa, PAGE_SIZE, vmr->perm);
	if (ret != 0) {
        return -ENOMAPPING;
	}

	return 0;
}