59 lines
1.7 KiB
C
59 lines
1.7 KiB
C
#include "Tier0/gdt.h"
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#include "Tier0/kstdlib.h"
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#include "Tier0/kstdio.h"
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#include "types.h"
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// Our GDT will be stored here.
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T_GDT_PTR g_GDTPointer;
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T_GDT_SEGMENT g_GDTEntries[5];
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void gdt_entry_create(u8 Index, u32 Base, u32 Limit, T_GDT_RING DPL, \
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T_GDT_EXECUTABLE Code, T_GDT_RW ReadWrite, u8 Long)
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{
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g_GDTEntries[Index].LimitLow = Limit & 0xFFFF;
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g_GDTEntries[Index].BaseLow = Base & 0xFFFF;
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g_GDTEntries[Index].BaseMiddle = (Base >> 16) & 0xFF;
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g_GDTEntries[Index].SegmentType = ((u8)Code << 3);
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g_GDTEntries[Index].SegmentType |= ((u8)ReadWrite << 1);
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g_GDTEntries[Index].DescriptorType = 1;
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g_GDTEntries[Index].DPL = DPL;
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g_GDTEntries[Index].Present = 1;
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g_GDTEntries[Index].LimitMiddle = Limit >> 16;
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g_GDTEntries[Index].SystemAvailable = 0;
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g_GDTEntries[Index].LongMode = Long;
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g_GDTEntries[Index].OperationSize = !Long;
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g_GDTEntries[Index].Granularity = 1;
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g_GDTEntries[Index].BaseHigh = Base >> 24;
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}
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void gdt_entry_create_null(u8 Index)
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{
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kmemset(&g_GDTEntries[Index], 0, 8);
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}
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void gdt_create_flat(void)
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{
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g_GDTPointer.Size = sizeof(T_GDT_SEGMENT) * 5 - 1;
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g_GDTPointer.Address = (u64)&g_GDTEntries;
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gdt_entry_create_null(0);
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gdt_entry_create(1, 0, 0xFFFFFFFF, GDT_RING0, GDT_EXECUTABLE, GDT_RW, 0);
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gdt_entry_create(2, 0, 0xFFFFFFFF, GDT_RING0, GDT_NOT_EXECUTABLE, GDT_RW, 0);
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gdt_entry_create(3, 0, 0xFFFFFFFF, GDT_RING0, GDT_EXECUTABLE, GDT_RW, 1);
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gdt_entry_create(4, 0, 0xFFFFFFFF, GDT_RING0, GDT_NOT_EXECUTABLE, GDT_RW, 1);
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kprintf("[i] Setting GDT:\n");
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for (u32 i = 0; i < 5; i++)
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{
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kprintf("%x", *((u32 *)g_GDTEntries + 2 * i + 1));
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kprintf("%x\n", *((u32 *)g_GDTEntries + 2 * i));
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}
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// gdt_flush();
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}
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