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#include "arch/x86_64/tables.h"
#include "arch/x86_64/processor.h"
#include "string.h"
static segment_descriptor_t s_gdt[] = {
{ 0 }, //Kernel NULL
{ //Kernel Code
.limit_0_15 = 0xFFFF,
.base_0_15 = 0x0,
.type = CD_SEGMENT_TYPE_CODE | CD_SEGMENT_TYPE_WRITEABLE,
.s = 1,
.dpl = 0,
.p = 1,
.limit_16_19 = 0xF,
.avl = 0,
.l = 1,
.d_b = 0,
.g = 1,
.base_24_31 = 0x0
},
{ //Kernel Data
.limit_0_15 = 0xFFFF,
.base_0_15 = 0x0,
.type = CD_SEGMENT_TYPE_WRITEABLE,
.s = 1,
.dpl = 0,
.p = 1,
.limit_16_19 = 0xF,
.avl = 0,
.l = 0,
.d_b = 1,
.g = 1,
.base_24_31 = 0x0
},
{ 0 }, //User NULL
{ //User Data
.limit_0_15 = 0xFFFF,
.base_0_15 = 0x0,
.type = CD_SEGMENT_TYPE_WRITEABLE,
.s = 1,
.dpl = 3,
.p = 1,
.limit_16_19 = 0xF,
.avl = 0,
.l = 0,
.d_b = 1,
.g = 1,
.base_24_31 = 0x0
},
{ //User Code
.limit_0_15 = 0xFFFF,
.base_0_15 = 0x0,
.type = CD_SEGMENT_TYPE_CODE | CD_SEGMENT_TYPE_WRITEABLE,
.s = 1,
.dpl = 3,
.p = 1,
.limit_16_19 = 0xF,
.avl = 0,
.l = 1,
.d_b = 0,
.g = 1,
.base_24_31 = 0x0
},
{ //TSS Low
.limit_0_15 = 0,
.base_0_15 = 0,
.base_16_23 = 0,
.type = S_SEGMENT_TYPE_TSS_AVAIL,
.avl = 0,
.s = 0,
.dpl = 0,
.p = 1,
.limit_16_19 = 0,
.l = 0,
.d_b = 0,
.g = 0,
.base_24_31 = 0
},
{ 0 } //TSS High
};
void
gdt_setup(processor_t *processor)
{
memcpy(processor->gdt, s_gdt, sizeof(s_gdt));
processor->gdtr.base = (uintptr_t)&s_gdt;
processor->gdtr.length = sizeof(s_gdt) - 1;
segment_descriptor_t *tss_lo = &processor->gdt[GDT_ENTRY_TSS_LOW];
segment_descriptor_t *tss_hi = &processor->gdt[GDT_ENTRY_TSS_HIGH];
uintptr_t tssb = (uintptr_t)&processor->tss;
tss_lo->base_0_15 = tssb & 0xFFFF;
tss_lo->base_16_23 = (tssb >> 16) & 0xFF;
tss_lo->base_24_31 = (tssb >> 24) & 0xFF;
tss_hi->limit_0_15 = (tssb >> 32) & 0xFFFF;
tss_hi->base_0_15 = (tssb >> 48) & 0xFFFF;
size_t tssl = sizeof(tss_t);
tss_lo->limit_0_15 = tssl & 0xFFFF;
tss_lo->limit_16_19 = (tssl >> 16) & 0xF;
processor->tss.iopb = tssl;
extern void gdt_load(void*);
gdt_load(&processor->gdtr);
extern void tss_flush(uint16_t);
tss_flush(GDT_ENTRY_TSS_LOW * sizeof(segment_descriptor_t));
}
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