include/libcpu/page.h

0001 /* SPDX-License-Identifier: BSD-2-Clause */
0002
0003 /*
0004  * Copyright (c) 2018 Amaan Cheval <amaan.cheval@gmail.com>
0005  *
0006  * Redistribution and use in source and binary forms, with or without
0007  * modification, are permitted provided that the following conditions
0008  * are met:
0009  * 1. Redistributions of source code must retain the above copyright
0010  *    notice, this list of conditions and the following disclaimer.
0011  * 2. Redistributions in binary form must reproduce the above copyright
0012  *    notice, this list of conditions and the following disclaimer in the
0013  *    documentation and/or other materials provided with the distribution.
0014  *
0015  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
0016  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
0017  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
0018  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
0019  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
0020  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
0021  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
0022  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
0023  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
0024  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
0025  * SUCH DAMAGE.
0026  */
0027
0028 #ifndef _LIBCPU_AMD64_PAGE_H
0029 #define _LIBCPU_AMD64_PAGE_H
0030
0031 #ifndef ASM
0032
0033 #define NUM_PAGE_TABLE_ENTRIES 512
0034
0035 extern uint64_t amd64_pml4[NUM_PAGE_TABLE_ENTRIES];
0036 extern uint64_t amd64_pdpt[NUM_PAGE_TABLE_ENTRIES];
0037
0038 bool paging_1gib_pages_supported(void);
0039 uint8_t get_maxphysaddr(void);
0040 uint64_t get_mask_for_bits(uint8_t start, uint8_t end);
0041 uint64_t create_cr3_entry(
0042   uint64_t phys_addr, uint8_t maxphysaddr, uint64_t flags
0043 );
0044 uint64_t create_pml4_entry(
0045   uint64_t phys_addr, uint8_t maxphysaddr, uint64_t flags
0046 );
0047 uint64_t create_pdpt_entry(
0048   uint64_t phys_addr, uint8_t maxphysaddr, uint64_t flags
0049 );
0050
0051 void paging_init(void);
0052
0053 #define PAGE_FLAGS_PRESENT          (1 << 0)
0054 #define PAGE_FLAGS_WRITABLE         (1 << 1)
0055 #define PAGE_FLAGS_USER_ACCESSIBLE  (1 << 2)
0056 #define PAGE_FLAGS_WRITE_THROUGH    (1 << 3)
0057 #define PAGE_FLAGS_NO_CACHE         (1 << 4)
0058 #define PAGE_FLAGS_ACCESSED         (1 << 5)
0059 #define PAGE_FLAGS_DIRTY            (1 << 6)
0060 #define PAGE_FLAGS_HUGE_PAGE        (1 << 7)
0061 #define PAGE_FLAGS_GLOBAL           (1 << 8)
0062 #define PAGE_FLAGS_NO_EXECUTE       (1 << 63)
0063
0064 #define PAGE_FLAGS_DEFAULTS                                      \
0065   (PAGE_FLAGS_PRESENT | PAGE_FLAGS_WRITABLE | PAGE_FLAGS_NO_CACHE)
0066
0067 #endif /* !ASM */
0068 #endif