/* This is similar with the one in start.S. However the previous one
* cannot be accessed in user process, because its virtual address is
* below 0xC0000000, and is not in the user process' address space. */
void
init_segment(void) {
memset(gdt, 0, sizeof(gdt));
set_segment(&gdt[SEG_KERNEL_CODE], DPL_KERNEL, SEG_EXECUTABLE | SEG_READABLE);
set_segment(&gdt[SEG_KERNEL_DATA], DPL_KERNEL, SEG_WRITABLE );
write_gdtr(gdt, sizeof(gdt));
}
void
init_segment(void) {
memset(gdt, 0, sizeof(gdt));
set_segment(&gdt[SEG_KERNEL_CODE], DPL_KERNEL, SEG_EXECUTABLE | SEG_READABLE);
set_segment(&gdt[SEG_KERNEL_DATA], DPL_KERNEL, SEG_WRITABLE );
set_segment(&gdt[SEG_USER_CODE], DPL_USER, SEG_EXECUTABLE | SEG_READABLE);
set_segment(&gdt[SEG_USER_DATA], DPL_USER, SEG_WRITABLE );
write_gdtr(gdt, sizeof(gdt));
set_tss(&gdt[SEG_TSS]);
write_tr( SELECTOR_USER(SEG_TSS) );
}