/* Copyright (C) 2021,2022 fef <owo@fef.moe>.  All rights reserved. */

#pragma once
#define _ARCH_PAGE_H_

/**
 * @brief Data structures and constants for paging on x86 (please end my suffering).
 */

#include <arch/vmparam.h>

#define __HAVE_HUGEPAGES

/** @brief Binary logarithm of `PAGE_SIZE`. */
#define PAGE_SHIFT 12
/** @brief Page size in bytes. */
#define PAGE_SIZE (1 << PAGE_SHIFT)

#ifdef __x86_64__
#include <amd64/page.h>
#else
#include <i386/page.h>
#endif

#define HUGEPAGE_SIZE (1 << HUGEPAGE_SHIFT)
#ifdef __HAVE_GIGAPAGES
#define GIGAPAGE_SIZE (1 << GIGAPAGE_SHIFT)
#endif

#ifndef _ASM_SOURCE

#include <arch/multiboot.h>

/** @brief Initialize `vm_page_array` based on the multiboot memory map. */
void x86_paging_init(struct mb2_tag_mmap *mmap);

/** @brief Pointer bitmask to get the base address of their page. */
#define PAGE_MASK ( ~((unsigned long)PAGE_SIZE - 1) )
/** @brief Pointer bitmask to get the base address of their huge page. */
#define HUGEPAGE_MASK ( ~((unsigned long)HUGEPAGE_SIZE - 1) )

#define PAGE_ALIGN(ptr) ((typeof(ptr))( (uintptr_t)(ptr) & PAGE_MASK ))
#define HUGEPAGE_ALIGN(ptr) ((typeof(ptr))( (uintptr_t)(ptr) & HUGEPAGE_MASK ))
#ifdef __HAVE_GIGAPAGES
#define GIGAPAGE_MASK ( ~((unsigned long)GIGAPAGE_SIZE - 1) )
#define GIGAPAGE_ALIGN(ptr) ((typeof(ptr))( (uintptr_t)(ptr) & GIGAPAGE_MASK ))
#endif

/* page fault status code bits */
#define X86_PF_PRESENT		(1u << 0)
#define X86_PF_WRITE		(1u << 1)
#define X86_PF_USER		(1u << 2)
#define X86_PF_RESERVED		(1u << 3)
#define X86_PF_INSTR		(1u << 4)
#define X86_PF_PKEY		(1u << 5)
#define X86_PF_SHADOW_STACK	(1u << 6)
#define X86_PF_SGX		(1u << 15)

/**
 * @brief Get the physical address a virtual one is currently mapped to.
 *
 * @param virt virtual address
 * @returns The physical address, or -1 cast to `vm_paddr_t` if there is no mapping
 */
vm_paddr_t vtophys(void *virt);

static inline void vm_flush(void)
{
	register_t tmp;
	__asm__ volatile(
	"	mov	%%cr3,	%0	\n"
	"	mov	%0,	%%cr3	\n"
	: "=r"(tmp)
	:
	: "memory"
	);
}

#endif /* not _ASM_SOURCE */