mirror of
https://github.com/Fennix-Project/Kernel.git
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73 lines
3.1 KiB
C++
73 lines
3.1 KiB
C++
#include "gdt.hpp"
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#include <memory.hpp>
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#include <cpu.hpp>
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#include <debug.h>
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namespace GlobalDescriptorTable
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{
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static GlobalDescriptorTableEntries GDTEntries = {
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{.Length = 0x0000, .BaseLow = 0x0000, .BaseMiddle = 0x00, .Access = 0b00000000, .Flags = 0b00000000, .BaseHigh = 0x00}, // null
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{.Length = 0x0000, .BaseLow = 0x0000, .BaseMiddle = 0x00, .Access = 0b10011010, .Flags = 0b00100000, .BaseHigh = 0x00}, // kernel code
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{.Length = 0x0000, .BaseLow = 0x0000, .BaseMiddle = 0x00, .Access = 0b10010010, .Flags = 0b00000000, .BaseHigh = 0x00}, // kernel data
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{.Length = 0x0000, .BaseLow = 0x0000, .BaseMiddle = 0x00, .Access = 0b11111010, .Flags = 0b00100000, .BaseHigh = 0x00}, // user code
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{.Length = 0x0000, .BaseLow = 0x0000, .BaseMiddle = 0x00, .Access = 0b11110010, .Flags = 0b00000000, .BaseHigh = 0x00}, // user data
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{.Length = 0, .Low = 0, .Middle = 0, .Flags1 = 0b10001001, .Flags2 = 0b00000000, .High = 0, .Upper32 = 0, .Reserved = 0}}; // tss
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GlobalDescriptorTableDescriptor gdt = {.Length = sizeof(GlobalDescriptorTableEntries) - 1, .Entries = &GDTEntries};
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TaskStateSegment tss[256] = {
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0,
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{0, 0, 0},
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0,
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{0, 0, 0, 0, 0, 0, 0},
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0,
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0,
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};
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void Init(int Core)
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{
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CPU::x64::lgdt(&gdt);
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asmv("movq %%rsp, %%rax\n"
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"pushq $16\n"
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"pushq %%rax\n"
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"pushfq\n"
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"pushq $8\n"
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"pushq $1f\n"
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"iretq\n"
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"1:\n"
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"movw $16, %%ax\n"
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"movw %%ax, %%ds\n"
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"movw %%ax, %%es\n"
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"movw $0x1b, %%ax\n"
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"movw %%ax, %%fs\n"
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"movw %%ax, %%gs\n" ::
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: "memory", "rax");
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uint64_t Base = (uint64_t)&tss[Core];
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gdt.Entries->TaskStateSegment.Length = Base + sizeof(tss[0]);
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gdt.Entries->TaskStateSegment.Low = (uint16_t)(Base & 0xFFFF);
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gdt.Entries->TaskStateSegment.Middle = (uint8_t)((Base >> 16) & 0xFF);
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gdt.Entries->TaskStateSegment.High = (uint8_t)((Base >> 24) & 0xFF);
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gdt.Entries->TaskStateSegment.Upper32 = (uint32_t)((Base >> 32) & 0xFFFFFFFF);
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gdt.Entries->TaskStateSegment.Flags1 = 0b10001001;
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gdt.Entries->TaskStateSegment.Flags2 = 0b00000000;
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tss[Core].IOMapBaseAddressOffset = sizeof(TaskStateSegment);
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tss[Core].StackPointer[0] = (uint64_t)KernelAllocator.RequestPage();
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tss[Core].InterruptStackTable[0] = (uint64_t)KernelAllocator.RequestPage();
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tss[Core].InterruptStackTable[1] = (uint64_t)KernelAllocator.RequestPage();
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tss[Core].InterruptStackTable[2] = (uint64_t)KernelAllocator.RequestPage();
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CPU::x64::ltr(GDT_TSS);
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asm volatile("mov %%rsp, %0"
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: "=r"(tss[Core].StackPointer[0]));
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trace("GDT_KERNEL_CODE: %#lx", GDT_KERNEL_CODE);
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trace("GDT_KERNEL_DATA: %#lx", GDT_KERNEL_DATA);
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trace("GDT_USER_DATA: %#lx", GDT_USER_DATA);
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trace("GDT_USER_CODE: %#lx", GDT_USER_CODE);
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trace("GDT_TSS: %#lx", GDT_TSS);
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trace("Global Descriptor Table initialized");
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}
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} |