/* Calcite, kernel/include/paging.h
 * Copyright 2025 Benji Dial
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or (at
 * your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program. If not, see <https://www.gnu.org/licenses/>.
 */

#pragma once

#include <stdint.h>

//kernel physical and virtual bases are passed so that we can compute the
//physical addresses of the kernel's statically allocated paging structures.
void init_paging(uint64_t kernel_physical_base, void *kernel_virtual_base);

//base and length should be page-aligned
void mark_physical_memory_free(uint64_t base, uint64_t length);

//maps one page. physical and virtual bases should be page-aligned.
//virtual address should be within kernel range.
void map_in_kernel_page_table(
  uint64_t physical_base, void *virtual_base, int writable, int executable);

//returns a region of contiguous pages in kernel virtual memory where nothing
//is mapped. length should be page-aligned.
void *find_free_kernel_region(uint64_t length);

//implemented in paging.asm. the continuation should be noreturn.
[[noreturn]] void switch_to_kernel_page_tables(void (*continuation)());