linux-stable-rt/include/asm-um/ldt-x86_64.h

/*
 * Copyright (C) 2004 Fujitsu Siemens Computers GmbH
 * Licensed under the GPL
 *
 * Author: Bodo Stroesser <bstroesser@fujitsu-siemens.com>
 */

#ifndef __ASM_LDT_X86_64_H
#define __ASM_LDT_X86_64_H

#include "asm/semaphore.h"
#include "asm/arch/ldt.h"

struct mmu_context_skas;
extern void ldt_host_info(void);
extern long init_new_ldt(struct mmu_context_skas * to_mm,
			 struct mmu_context_skas * from_mm);
extern void free_ldt(struct mmu_context_skas * mm);

#define LDT_PAGES_MAX \
	((LDT_ENTRIES * LDT_ENTRY_SIZE)/PAGE_SIZE)
#define LDT_ENTRIES_PER_PAGE \
	(PAGE_SIZE/LDT_ENTRY_SIZE)
#define LDT_DIRECT_ENTRIES \
	((LDT_PAGES_MAX*sizeof(void *))/LDT_ENTRY_SIZE)

struct ldt_entry {
	__u32 a;
	__u32 b;
};

typedef struct uml_ldt {
	int entry_count;
	struct semaphore semaphore;
	union {
		struct ldt_entry * pages[LDT_PAGES_MAX];
		struct ldt_entry entries[LDT_DIRECT_ENTRIES];
	} u;
} uml_ldt_t;

/*
 * macros stolen from include/asm-x86_64/desc.h
 */
#define LDT_entry_a(info) \
	((((info)->base_addr & 0x0000ffff) << 16) | ((info)->limit & 0x0ffff))

/* Don't allow setting of the lm bit. It is useless anyways because
 * 64bit system calls require __USER_CS. */
#define LDT_entry_b(info) \
	(((info)->base_addr & 0xff000000) | \
	(((info)->base_addr & 0x00ff0000) >> 16) | \
	((info)->limit & 0xf0000) | \
	(((info)->read_exec_only ^ 1) << 9) | \
	((info)->contents << 10) | \
	(((info)->seg_not_present ^ 1) << 15) | \
	((info)->seg_32bit << 22) | \
	((info)->limit_in_pages << 23) | \
	((info)->useable << 20) | \
	/* ((info)->lm << 21) | */ \
	0x7000)

#define LDT_empty(info) (\
	(info)->base_addr	== 0	&& \
	(info)->limit		== 0	&& \
	(info)->contents	== 0	&& \
	(info)->read_exec_only	== 1	&& \
	(info)->seg_32bit	== 0	&& \
	(info)->limit_in_pages	== 0	&& \
	(info)->seg_not_present	== 1	&& \
	(info)->useable		== 0	&& \
	(info)->lm              == 0)

#endif