linux-sg2042/arch/x86/um/asm/mm_context.h

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

#ifndef __ASM_LDT_H
#define __ASM_LDT_H

#include <linux/mutex.h>
#include <asm/ldt.h>

extern void ldt_host_info(void);

#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 mutex lock;
	union {
		struct ldt_entry * pages[LDT_PAGES_MAX];
		struct ldt_entry entries[LDT_DIRECT_ENTRIES];
	} u;
} uml_ldt_t;

#define LDT_entry_a(info) \
	((((info)->base_addr & 0x0000ffff) << 16) | ((info)->limit & 0x0ffff))

#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) | \
	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	)

#ifdef CONFIG_X86_64
#define LDT_empty(info) (_LDT_empty(info) && ((info)->lm == 0))
#else
#define LDT_empty(info) (_LDT_empty(info))
#endif

struct uml_arch_mm_context {
	uml_ldt_t ldt;
};

#endif