visor/include/x86/gdt.h

#ifndef _VISOR_GDT_H_
#define _VISOR_GDT_H_

#include <stdint.h>

__attribute__ ((packed))
struct segdescr {
	uint16_t limit0;
	uint16_t base0;
	uint8_t  base1;
	uint8_t  access;
	uint8_t  flags;
	uint16_t base2;
	uint32_t base3;
	uint32_t reserved;
};

__attribute__ ((packed))
struct GDTR {
	uint16_t limit;
	uint64_t base;
};

__attribute__ ((packed))
struct TSS {
	uint32_t reserved0;
	uint64_t rsp0;
	uint64_t rsp1;
	uint64_t rsp2;
	uint64_t reserved1;
	uint64_t ist1;
	uint64_t ist2;
	uint64_t ist3;
	uint64_t ist4;
	uint64_t ist5;
	uint64_t ist6;
	uint64_t ist7;
	uint64_t reserved2;
	uint16_t reserved3;
	uint16_t iopb;
};

static inline struct GDTR
storegdt(void)
{
	struct GDTR gdtr;
	__asm__ ("sgdt %0\n\t" : "=m"(gdtr));
	return gdtr;
}

static inline void
setsegdescr(struct segdescr *descr, uint64_t base, uint32_t limit, uint8_t access, uint8_t flags)
{
	descr->limit0   = limit;
	descr->base0    = base;
	descr->base1    = base >> 16;
	descr->access   = access;
	descr->flags    = flags | (limit >> 16);
	descr->base2    = base >> 24;
	descr->base3    = base >> 32;
	descr->reserved = 0;
}

#endif