freebsd-dev/sys/amd64/include/segments.h

/*-
 * Copyright (c) 1989, 1990 William F. Jolitz
 * Copyright (c) 1990 The Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * William Jolitz.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *	from: @(#)segments.h	7.1 (Berkeley) 5/9/91
 * $FreeBSD$
 */

#ifndef _MACHINE_SEGMENTS_H_
#define	_MACHINE_SEGMENTS_H_

/*
 * AMD64 Segmentation Data Structures and definitions
 */

/*
 * Selectors
 */

#define	ISPL(s)	((s)&3)		/* what is the priority level of a selector */
#define	SEL_KPL	0		/* kernel priority level */
#define	SEL_UPL	3		/* user priority level */
#define	ISLDT(s)	((s)&SEL_LDT)	/* is it local or global */
#define	SEL_LDT	4		/* local descriptor table */
#define	IDXSEL(s)	(((s)>>3) & 0x1fff)		/* index of selector */
#define	LSEL(s,r)	(((s)<<3) | SEL_LDT | r)	/* a local selector */
#define	GSEL(s,r)	(((s)<<3) | r)			/* a global selector */

/*
 * User segment descriptors (%cs, %ds etc for compatability apps. 64 bit wide)
 * For long-mode apps, %cs only has the conforming bit in sd_type, the sd_dpl,
 * sd_p, sd_l and sd_def32 which must be zero).  %ds only has sd_p.
 */
struct	user_segment_descriptor {
	u_int64_t sd_lolimit:16;	/* segment extent (lsb) */
	u_int64_t sd_lobase:24;		/* segment base address (lsb) */
	u_int64_t sd_type:5;		/* segment type */
	u_int64_t sd_dpl:2;		/* segment descriptor priority level */
	u_int64_t sd_p:1;		/* segment descriptor present */
	u_int64_t sd_hilimit:4;		/* segment extent (msb) */
	u_int64_t sd_xx:1;		/* unused */
	u_int64_t sd_long:1;		/* long mode (cs only) */
	u_int64_t sd_def32:1;		/* default 32 vs 16 bit size */
	u_int64_t sd_gran:1;		/* limit granularity (byte/page units)*/
	u_int64_t sd_hibase:8;		/* segment base address  (msb) */
} __packed;

/*
 * System segment descriptors (128 bit wide)
 */
struct	system_segment_descriptor {
	u_int64_t sd_lolimit:16;	/* segment extent (lsb) */
	u_int64_t sd_lobase:24;		/* segment base address (lsb) */
	u_int64_t sd_type:5;		/* segment type */
	u_int64_t sd_dpl:2;		/* segment descriptor priority level */
	u_int64_t sd_p:1;		/* segment descriptor present */
	u_int64_t sd_hilimit:4;		/* segment extent (msb) */
	u_int64_t sd_xx0:3;		/* unused */
	u_int64_t sd_gran:1;		/* limit granularity (byte/page units)*/
	u_int64_t sd_hibase:40 __packed;/* segment base address  (msb) */
	u_int64_t sd_xx1:8;
	u_int64_t sd_mbz:5;		/* MUST be zero */
	u_int64_t sd_xx2:19;
} __packed;

/*
 * Gate descriptors (e.g. indirect descriptors, trap, interrupt etc. 128 bit)
 * Only interrupt and trap gates have gd_ist.
 */
struct	gate_descriptor {
	u_int64_t gd_looffset:16;	/* gate offset (lsb) */
	u_int64_t gd_selector:16;	/* gate segment selector */
	u_int64_t gd_ist:3;		/* IST table index */
	u_int64_t gd_xx:5;		/* unused */
	u_int64_t gd_type:5;		/* segment type */
	u_int64_t gd_dpl:2;		/* segment descriptor priority level */
	u_int64_t gd_p:1;		/* segment descriptor present */
	u_int64_t gd_hioffset:48 __packed;	/* gate offset (msb) */
	u_int64_t sd_xx1:32;
} __packed;

	/* system segments and gate types */
#define	SDT_SYSNULL	 0	/* system null */
#define	SDT_SYSLDT	 2	/* system 64 bit local descriptor table */
#define	SDT_SYSTSS	 9	/* system available 64 bit TSS */
#define	SDT_SYSBSY	11	/* system busy 64 bit TSS */
#define	SDT_SYSCGT	12	/* system 64 bit call gate */
#define	SDT_SYSIGT	14	/* system 64 bit interrupt gate */
#define	SDT_SYSTGT	15	/* system 64 bit trap gate */

	/* memory segment types */
#define	SDT_MEMRO	16	/* memory read only */
#define	SDT_MEMROA	17	/* memory read only accessed */
#define	SDT_MEMRW	18	/* memory read write */
#define	SDT_MEMRWA	19	/* memory read write accessed */
#define	SDT_MEMROD	20	/* memory read only expand dwn limit */
#define	SDT_MEMRODA	21	/* memory read only expand dwn limit accessed */
#define	SDT_MEMRWD	22	/* memory read write expand dwn limit */
#define	SDT_MEMRWDA	23	/* memory read write expand dwn limit accessed */
#define	SDT_MEME	24	/* memory execute only */
#define	SDT_MEMEA	25	/* memory execute only accessed */
#define	SDT_MEMER	26	/* memory execute read */
#define	SDT_MEMERA	27	/* memory execute read accessed */
#define	SDT_MEMEC	28	/* memory execute only conforming */
#define	SDT_MEMEAC	29	/* memory execute only accessed conforming */
#define	SDT_MEMERC	30	/* memory execute read conforming */
#define	SDT_MEMERAC	31	/* memory execute read accessed conforming */

/*
 * Software definitions are in this convenient format,
 * which are translated into inconvenient segment descriptors
 * when needed to be used by the 386 hardware
 */

struct	soft_segment_descriptor {
	unsigned long ssd_base;		/* segment base address  */
	unsigned long ssd_limit;	/* segment extent */
	unsigned long ssd_type:5;	/* segment type */
	unsigned long ssd_dpl:2;	/* segment descriptor priority level */
	unsigned long ssd_p:1;		/* segment descriptor present */
	unsigned long ssd_long:1;	/* long mode (for %cs) */
	unsigned long ssd_def32:1;	/* default 32 vs 16 bit size */
	unsigned long ssd_gran:1;	/* limit granularity (byte/page units)*/
} __packed;

/*
 * region descriptors, used to load gdt/idt tables before segments yet exist.
 */
struct region_descriptor {
	unsigned long rd_limit:16;		/* segment extent */
	unsigned long rd_base:64 __packed;	/* base address  */
} __packed;

/*
 * Size of IDT table
 */
#define	NIDT	256		/* 32 reserved, 16 h/w, 0 s/w, linux's 0x80 */
#define	NRSVIDT	32		/* reserved entries for cpu exceptions */

/*
 * Entries in the Global Descriptor Table (GDT)
 */
#define	GNULL_SEL	0	/* Null Descriptor */
#define	GCODE_SEL	1	/* Kernel Code Descriptor */
#define	GDATA_SEL	2	/* Kernel Data Descriptor */
#define	GUCODE32_SEL	3	/* User 32 bit code Descriptor */
#define	GUDATA_SEL	4	/* User 32/64 bit Data Descriptor */
#define	GUCODE_SEL	5	/* User 64 bit Code Descriptor */
#define	GPROC0_SEL	6	/* TSS for entering kernel etc  */
/* slot 6 is second half of GPROC0_SEL */
#define	NGDT 		8

#ifdef _KERNEL
extern struct user_segment_descriptor gdt[];
extern struct soft_segment_descriptor gdt_segs[];
extern struct gate_descriptor *idt;

void	lgdt(struct region_descriptor *rdp);
void	sdtossd(struct user_segment_descriptor *sdp,
	    struct soft_segment_descriptor *ssdp);
void	ssdtosd(struct soft_segment_descriptor *ssdp,
	    struct user_segment_descriptor *sdp);
void	ssdtosyssd(struct soft_segment_descriptor *ssdp,
	    struct system_segment_descriptor *sdp);
#endif /* _KERNEL */

#endif /* !_MACHINE_SEGMENTS_H_ */