60 lines
1.1 KiB
C
60 lines
1.1 KiB
C
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#pragma once
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#include "gdt/gdtc.h"
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#include "../../lib/include/string.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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asm volatile("mov (5 * 8) |0 , %eax; 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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uint32_t esp_addr =0 ;
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asm volatile ("movl %%esp, %0" : "=a"(esp_addr));
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tss0.esp0 = esp_addr;
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// Task Segment Descriptor
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add_descriptor(TASK_STATE_SEGMENT, (unsigned long)&tss0, sizeof(tss0), 0x89, 0x0);
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flush_tss();
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}
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