61 lines
1.2 KiB
C
61 lines
1.2 KiB
C
#pragma once
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#include "gdt/gdtc.h"
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#include <CoreLib/Memory.h>
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struct TaskStateSegment {
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uint32_t prev_tss;
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uint32_t esp0;
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uint32_t ss0;
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// everythinge else is unused
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uint32_t esp1;
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uint32_t ss1;
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uint32_t esp2;
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uint32_t ss2;
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uint32_t cr3;
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uint32_t eip;
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uint32_t eflags;
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uint32_t eax;
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uint32_t ecx;
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uint32_t edx;
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uint32_t ebx;
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uint32_t esp;
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uint32_t ebp;
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uint32_t esi;
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uint32_t edi;
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uint32_t es;
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uint32_t cs;
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uint32_t ss;
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uint32_t ds;
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uint32_t fs;
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uint32_t gs;
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uint32_t ldt;
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uint16_t trap;
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uint16_t iomap_base;
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}__attribute__((packed));
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TaskStateSegment tss0 ={};
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inline void flush_tss()
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{
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asm volatile("mov $0x2B, %ax ; ltr %ax");
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}
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void setup_tss(){
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// ensure the tss is zero'd
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memset((void*)&tss0, 0, sizeof(tss0));
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tss0.ss0 = (uint32_t) &GlobalDescriptorTable[KERNEL_DATA_SEGMENT];
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extern uint32_t stack_top;
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tss0.esp0 = (unsigned long)&stack_top;
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// Task Segment Descriptor
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uint32_t address = (unsigned long) &tss0;
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uint32_t size = sizeof(tss0);
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uint32_t limit = (address + size );
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add_descriptor(TASK_STATE_SEGMENT, address, limit- 1, 0xE9, 0x0);
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}
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