amd64/include/gdt.h

0001 /* SPDX-License-Identifier: BSD-2-Clause */
0002
0003 /**
0004  * @file
0005  *
0006  * @ingroup RTEMSBSPsX8664AMD64
0007  *
0008  * @brief Global Descriptor Table
0009  */
0010
0011 /*
0012  * Copyright (C) 2024 Matheus Pecoraro
0013  *
0014  * Redistribution and use in source and binary forms, with or without
0015  * modification, are permitted provided that the following conditions
0016  * are met:
0017  * 1. Redistributions of source code must retain the above copyright
0018  *    notice, this list of conditions and the following disclaimer.
0019  * 2. Redistributions in binary form must reproduce the above copyright
0020  *    notice, this list of conditions and the following disclaimer in the
0021  *    documentation and/or other materials provided with the distribution.
0022  *
0023  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
0024  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
0025  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
0026  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
0027  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
0028  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
0029  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
0030  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
0031  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
0032  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
0033  * POSSIBILITY OF SUCH DAMAGE.
0034  */
0035
0036 #ifndef GDT_H
0037 #define GDT_H
0038
0039 #define GDT_CODE_SEG_OFFSET 0x8
0040 #define GDT_DATA_SEG_OFFSET 0x10
0041
0042 #ifndef ASM
0043 #include <rtems/score/basedefs.h>
0044
0045 #include <stdint.h>
0046
0047 typedef struct {
0048     uint16_t limit_low;         /* Lower 16 bits of the limit */
0049     uint16_t base_low;          /* Lower 16 bits of the base */
0050     uint8_t  base_middle;       /* Next 8 bits of the base */
0051     uint8_t  access;            /* Access flags */
0052     uint8_t  gran_limit_middle; /* Granularity flags and upper 4 bits of the limit */
0053     uint8_t  base_high;         /* Last 8 bits of the base */
0054 } RTEMS_PACKED gdt_entry;
0055
0056 typedef struct {
0057     uint16_t size;
0058     uint64_t addr;
0059 } RTEMS_PACKED gdt_desc;
0060
0061 extern const gdt_desc amd64_gdt_descriptor;
0062 #endif // ASM
0063
0064 #endif // GDT_H