mirror of
https://github.com/Fennix-Project/Kernel.git
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127 lines
3.7 KiB
C++
127 lines
3.7 KiB
C++
#include "gdt.hpp"
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#include <memory.hpp>
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#include <smp.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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// null
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{.Length = 0x0,
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.BaseLow = 0x0,
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.BaseMiddle = 0x0,
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.Access = 0b00000000,
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.Flags = 0b00000000,
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.BaseHigh = 0x0},
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// kernel code
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{.Length = 0x0,
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.BaseLow = 0x0,
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.BaseMiddle = 0x0,
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.Access = RING0 |
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CODE_READABLE |
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CODE_SEGMENT |
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PRESENT,
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.Flags = _64BITS,
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.BaseHigh = 0x0},
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// kernel data
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{.Length = 0x0,
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.BaseLow = 0x0,
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.BaseMiddle = 0x0,
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.Access = RING0 |
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DATA_WRITEABLE |
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DATA_SEGMENT |
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PRESENT,
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.Flags = 0b00000000,
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.BaseHigh = 0x0},
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// user code
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{.Length = 0x0,
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.BaseLow = 0x0,
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.BaseMiddle = 0x0,
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.Access = CODE_READABLE |
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CODE_SEGMENT |
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RING3 |
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PRESENT,
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.Flags = _64BITS,
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.BaseHigh = 0x0},
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// user data
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{.Length = 0x0,
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.BaseLow = 0x0,
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.BaseMiddle = 0x0,
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.Access = DATA_WRITEABLE |
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DATA_SEGMENT |
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RING3 |
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PRESENT,
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.Flags = 0b00000000,
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.BaseHigh = 0x0},
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// tss
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{.Length = 0x0,
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.Low = 0x0,
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.Middle = 0x0,
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.Flags1 = 0b10001001,
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.Flags2 = 0b00000000,
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.High = 0x0,
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.Upper32 = 0x0,
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.Reserved = 0x0}};
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GlobalDescriptorTableDescriptor gdt = {.Length = sizeof(GlobalDescriptorTableEntries) - 1, .Entries = &GDTEntries};
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TaskStateSegment tss[MAX_CPU] = {
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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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__attribute__((no_stack_protector)) 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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: "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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asmv("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_CODE: %#lx", GDT_USER_CODE);
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trace("GDT_USER_DATA: %#lx", GDT_USER_DATA);
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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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}
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