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/*
* Copyright (c) 2023 Ian Marco Moffett and the VegaOS team.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of VegaOS nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef AMD64_GDT_H_
#define AMD64_GDT_H_
#include <sys/types.h>
#include <sys/cdefs.h>
#define GDT_TSS 5
#define KERNEL_CS 0x8
#define KERNEL_DS 0x10
struct __packed gdt_entry {
uint16_t limit;
uint16_t base_low;
uint8_t base_mid;
uint8_t access;
uint8_t granularity;
uint8_t base_hi;
};
struct __packed gdtr {
uint16_t limit;
uintptr_t offset;
};
static inline void
gdt_load(struct gdtr *gdtr)
{
__asm("lgdt %0\n"
"push $8\n" /* Push CS */
"lea 1f(%%rip), %%rax\n" /* Load 1 label address into RAX */
"push %%rax\n" /* Push the return address (label 1) */
"lretq\n" /* Far return to update CS */
"1:\n"
" mov $0x10, %%eax\n"
" mov %%eax, %%ds\n"
" mov %%eax, %%es\n"
" mov %%eax, %%fs\n"
" mov %%eax, %%gs\n"
" mov %%eax, %%ss\n"
:
: "m" (*gdtr)
: "rax", "memory"
);
}
extern struct gdt_entry g_gdt[256];
extern struct gdtr g_gdtr;
#endif /* !AMD64_GDT_H_ */
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