You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
97 lines
2.5 KiB
C
97 lines
2.5 KiB
C
/* Copyright (C) 2021,2022 fef <owo@fef.moe>. All rights reserved. */
|
|
|
|
#pragma once
|
|
|
|
#include <gay/config.h>
|
|
|
|
#define X86_32_KERN_CS 0x10
|
|
#define X86_32_USER_CS 0x18
|
|
#define X86_64_KERN_CS 0x20
|
|
#define X86_64_USER_CS 0x28
|
|
#define X86_KERN_DS 0x30
|
|
#define X86_USER_DS 0x38
|
|
#define X86_KERN_TSS 0x40
|
|
#define X86_USER_TSS 0x50
|
|
|
|
#ifndef _ASM_SOURCE
|
|
|
|
/*
|
|
* This code is mostly obsolete (until we need to actually manipulate the GDT
|
|
* when there is long mode support and we want to enable 32-bit compatibility
|
|
* mode). I wrote this because i initially wanted to use it for an encoder that
|
|
* would dynamically initialize the GDT entries at runtime, but fuck that.
|
|
* I've lost way more than enough time on the utterly useless GDT, so we'll just
|
|
* leave this here as it is until we actually need it. See arch/mm/segment.S
|
|
* for the actual GDT entries and how the GDT is loaded.
|
|
*/
|
|
|
|
#include <arch/page.h>
|
|
|
|
#include <gay/cdefs.h>
|
|
#include <gay/types.h>
|
|
|
|
/** @brief x86 Global Descriptor Table entry as used by the kernel. */
|
|
struct x86_gdt_entry {
|
|
u32 base;
|
|
unsigned limit:20;
|
|
unsigned flags:4;
|
|
#define X86_GDT_SIZE (1u << 2)
|
|
#define X86_GDT_GRANULARITY (1u << 3)
|
|
u8 access;
|
|
#define X86_GDT_ACCESSED (1u << 0)
|
|
#define X86_GDT_RW (1u << 1)
|
|
#define X86_GDT_DIRECTION (1u << 2) /* for data selectors (executable not set) */
|
|
#define X86_GDT_CONFORMING (1u << 2) /* for code selectors (executable set) */
|
|
#define X86_GDT_EXEC (1u << 3)
|
|
#define X86_GDT_TYPE (1u << 4) /* 1 for code/data, 0 for system (e.g. TSS) */
|
|
#define X86_GDT_PRIVL_SHIFT (5)
|
|
#define X86_GDT_PRIVL_MASK (3u << X86_GDT_PRIVL_SHIFT)
|
|
#define X86_GDT_PRIVL(n) (((n) << X86_GDT_PRIVL_SHIFT) & X86_GDT_PRIVL_MASK)
|
|
#define X86_GDT_PRESENT (1u << 7)
|
|
};
|
|
|
|
/** @brief x86 Global Descriptor Table entry as laid out in hardware. */
|
|
struct x86_insane_gdt_entry {
|
|
u16 limit0;
|
|
u16 base0;
|
|
u8 base1;
|
|
u8 access;
|
|
unsigned limit1:4;
|
|
unsigned flags:4;
|
|
u8 base2;
|
|
} __packed;
|
|
|
|
/** @brief The main GDT (defined in `arch/mm/segment.S`) */
|
|
extern struct x86_insane_gdt_entry x86_gdt[5];
|
|
|
|
struct x86_tss {
|
|
u16 link; u16 _reserved0;
|
|
u32 esp0;
|
|
u16 ss0; u16 _reserved1;
|
|
u32 esp1;
|
|
u16 ss1; u16 _reserved2;
|
|
u32 esp2;
|
|
u16 ss2; u16 _reserved3;
|
|
u32 cr3;
|
|
u32 eip;
|
|
u32 eflags;
|
|
u32 eax;
|
|
u32 ecx;
|
|
u32 edx;
|
|
u32 ebx;
|
|
u32 esp;
|
|
u32 ebp;
|
|
u32 esi;
|
|
u32 edi;
|
|
u16 es; u16 _reserved4;
|
|
u16 cs; u16 _reserved5;
|
|
u16 ss; u16 _reserved6;
|
|
u16 ds; u16 _reserved7;
|
|
u16 fs; u16 _reserved8;
|
|
u16 gs; u16 _reserved9;
|
|
u16 ldtr; u16 _reserved10;
|
|
u16 _reserved11; u16 iopb_offset;
|
|
};
|
|
|
|
#endif /* not _ASM_SOURCE */
|