luciaos/tss.c

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C
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2022-09-14 21:54:59 -05:00
#include <stdint.h>
struct __attribute__((__packed__)) tss_entry_struct {
uint32_t prev_tss;
uint32_t esp0;
uint32_t ss0;
uint32_t esp1;
uint32_t ss1;
uint32_t esp2;
uint32_t ss2;
uint32_t cr3;
uint32_t eip;
uint32_t eflags;
uint32_t eax;
uint32_t ecx;
uint32_t edx;
uint32_t ebx;
uint32_t esp;
uint32_t ebp;
uint32_t esi;
uint32_t edi;
uint32_t es;
uint32_t cs;
uint32_t ss;
uint32_t ds;
uint32_t fs;
uint32_t gs;
uint32_t ldt;
uint32_t trap;
uint32_t iomap_base;
};
struct tss_entry_struct *tss_data;
void write_tss() {
tss_data = (struct tss_entry_struct *)0x20000;
for (int i = 0; i < 0x2080; i++)
((uint8_t*)tss_data)[i] = 0;
tss_data->ss0 = 0x10;
tss_data->esp0 = 0x400000;
tss_data->iomap_base = 0x80;
}
extern void flushTSS();
void setup_tss() {
write_tss();
flushTSS();
}