[apple/xnu.git] / osfmk / i386 / seg.h

/*
 * Copyright (c) 2000-2012 Apple Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 *
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 *
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 *
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */
/*
 * @OSF_COPYRIGHT@
 */
/*
 * Mach Operating System
 * Copyright (c) 1991,1990 Carnegie Mellon University
 * All Rights Reserved.
 *
 * Permission to use, copy, modify and distribute this software and its
 * documentation is hereby granted, provided that both the copyright
 * notice and this permission notice appear in all copies of the
 * software, derivative works or modified versions, and any portions
 * thereof, and that both notices appear in supporting documentation.
 *
 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
 * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
 *
 * Carnegie Mellon requests users of this software to return to
 *
 *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
 *  School of Computer Science
 *  Carnegie Mellon University
 *  Pittsburgh PA 15213-3890
 *
 * any improvements or extensions that they make and grant Carnegie Mellon
 * the rights to redistribute these changes.
 */
#ifndef _I386_SEG_H_
#define _I386_SEG_H_
#ifndef __ASSEMBLER__
#include <stdint.h>
#include <mach/vm_types.h>
#include <mach/vm_param.h>
#include <architecture/i386/sel.h>

/*
 * i386 segmentation.
 */

static inline uint16_t
sel_to_selector(sel_t   sel)
{
	union {
		sel_t           sel;
		uint16_t        selector;
	} tconv;

	tconv.sel = sel;

	return tconv.selector;
}

static inline sel_t
selector_to_sel(uint16_t selector)
{
	union {
		uint16_t        selector;
		sel_t           sel;
	} tconv;

	tconv.selector = selector;

	return tconv.sel;
}

#define LDTSZ_MAX       8192    /* maximal size of the kernel ldt in entries */
#define LDTSZ_DFL       (128)
#define LDTSZ           (LDTSZ_MAX)
#define LDTSZ_MIN       SEL_TO_INDEX(USER_SETTABLE)
/* kernel ldt entries */

#define GDTSZ           19

/*
 * Interrupt table is always 256 entries long.
 */
#define IDTSZ           256

#include <sys/cdefs.h>

/*
 * Real segment descriptor.
 */
struct real_descriptor {
	uint32_t        limit_low:16,   /* limit 0..15 */
	    base_low:16,                /* base  0..15 */
	    base_med:8,                 /* base  16..23 */
	    access:8,                   /* access byte */
	    limit_high:4,               /* limit 16..19 */
	    granularity:4,              /* granularity */
	    base_high:8;                /* base 24..31 */
};
struct real_descriptor64 {
	uint32_t        limit_low16:16, /* limit 0..15 */
	    base_low16:16,              /* base  0..15 */
	    base_med8:8,                /* base  16..23 */
	    access8:8,                  /* access byte */
	    limit_high4:4,              /* limit 16..19 */
	    granularity4:4,             /* granularity */
	    base_high8:8,               /* base 24..31 */
	    base_top32:32,              /* base 32..63 */
	    reserved32:32;              /* reserved/zero */
};
struct real_gate {
	uint32_t        offset_low:16,  /* offset 0..15 */
	    selector:16,
	    word_count:8,
	    access:8,
	    offset_high:16;             /* offset 16..31 */
};
struct real_gate64 {
	uint32_t        offset_low16:16,        /* offset 0..15 */
	    selector16:16,
	    IST:3,
	    zeroes5:5,
	    access8:8,
	    offset_high16:16,                   /* offset 16..31 */
	    offset_top32:32,                    /* offset 32..63 */
	    reserved32:32;                      /* reserved/zero */
};

#define MAKE_REAL_DESCRIPTOR(base, lim, gran, acc) {\
	.limit_low = lim & 0xffff, \
	.limit_high = (lim >> 16) & 0xf, \
	.base_low = base & 0xffff, \
	.base_med = (base >> 16) & 0xff, \
	.base_high = (base >> 24) & 0xff, \
	.access = acc, \
	.granularity = gran \
}

/*
 * We build descriptors and gates in a 'fake' format to let the
 * fields be contiguous.  We shuffle them into the real format
 * at runtime.
 */
struct fake_descriptor {
	uint32_t        offset:32;              /* offset */
	uint32_t        lim_or_seg:20;          /* limit */
	                                        /* or segment, for gate */
	uint32_t        size_or_wdct:4;         /* size/granularity */
	                                        /* word count, for gate */
	uint32_t        access:8;               /* access */
};
struct fake_descriptor64 {
	uint64_t        offset64;               /* offset [0..31,32..63] */
	uint32_t        lim_or_seg:20;          /* limit */
	                                        /* or segment, for gate */
	uint32_t        size_or_IST:4;          /* size/granularity */
	                                        /* IST for gates */
	uint32_t        access:8;               /* access */
	uint32_t        reserved:32;            /* reserved/zero */
};

typedef struct __attribute__((packed)) {
	uint16_t        size;
	void            *ptr;
} x86_64_desc_register_t;


/*
 * Boot-time data for master (or only) CPU
 */
extern struct real_descriptor   master_gdt[GDTSZ];
extern struct real_descriptor   master_ldt[];
extern struct i386_tss          master_ktss;
extern struct sysenter_stack    master_sstk;

extern struct fake_descriptor64 master_idt64[IDTSZ];
extern struct x86_64_tss        master_ktss64;

__BEGIN_DECLS

extern char                     df_task_stack[];
extern char                     df_task_stack_end[];
extern struct i386_tss          master_dftss;
extern void                     df_task_start(void);

extern char                     mc_task_stack[];
extern char                     mc_task_stack_end[];
extern struct i386_tss          master_mctss;
extern void                     mc_task_start(void);

__END_DECLS

#endif  /*__ASSEMBLER__*/

#define SZ_64           0x2                     /* 64-bit segment */
#define SZ_32           0x4                     /* 32-bit segment */
#define SZ_G            0x8                     /* 4K limit field */

#define ACC_A           0x01                    /* accessed */
#define ACC_TYPE        0x1e                    /* type field: */

#define ACC_TYPE_SYSTEM 0x00                    /* system descriptors: */

#define ACC_LDT         0x02                        /* LDT */
#define ACC_CALL_GATE_16 0x04                       /* 16-bit call gate */
#define ACC_TASK_GATE   0x05                        /* task gate */
#define ACC_TSS         0x09                        /* task segment */
#define ACC_CALL_GATE   0x0c                        /* call gate */
#define ACC_INTR_GATE   0x0e                        /* interrupt gate */
#define ACC_TRAP_GATE   0x0f                        /* trap gate */

#define ACC_TSS_BUSY    0x02                        /* task busy */

#define ACC_TYPE_USER   0x10                    /* user descriptors */

#define ACC_DATA        0x10                        /* data */
#define ACC_DATA_W      0x12                        /* data, writable */
#define ACC_DATA_E      0x14                        /* data, expand-down */
#define ACC_DATA_EW     0x16                        /* data, expand-down,
	                                             *        writable */
#define ACC_CODE        0x18                        /* code */
#define ACC_CODE_R      0x1a                        /* code, readable */
#define ACC_CODE_C      0x1c                        /* code, conforming */
#define ACC_CODE_CR     0x1e                        /* code, conforming,
	                                             *  readable */
#define ACC_PL          0x60                    /* access rights: */
#define ACC_PL_K        0x00                    /* kernel access only */
#define ACC_PL_U        0x60                    /* user access */
#define ACC_P           0x80                    /* segment present */

/*
 * Components of a selector
 */
#define SEL_LDTS        0x04                    /* local selector */
#define SEL_PL          0x03                    /* privilege level: */
#define SEL_PL_K        0x00                        /* kernel selector */
#define SEL_PL_U        0x03                        /* user selector */

/*
 * Convert selector to descriptor table index.
 */
#define sel_idx(sel)    (selector_to_sel(sel).index)
#define SEL_TO_INDEX(s) ((s)>>3)

#define NULL_SEG        0


/*
 * Kernel descriptors for MACH - 64-bit flat address space.
 */
#define KERNEL64_CS     0x08            /* 1:  K64 code */
#define SYSENTER_CS     0x0b            /*     U32 sysenter pseudo-segment */
#define KERNEL64_SS     0x10            /* 2:  KERNEL64_CS+8 for syscall */
#define USER_CS         0x1b            /* 3:  U32 code */
#define USER_DS         0x23            /* 4:  USER_CS+8 for sysret */
#define USER64_CS       0x2b            /* 5:  USER_CS+16 for sysret */
#define USER64_DS       USER_DS         /*     U64 data pseudo-segment */
#define KERNEL_LDT      0x30            /* 6:  */
                                        /* 7:  other 8 bytes of KERNEL_LDT */
#define KERNEL_TSS      0x40            /* 8:  */
                                        /* 9:  other 8 bytes of KERNEL_TSS */
#define KERNEL32_CS     0x50            /* 10: */
#define USER_LDT        0x58            /* 11: */
                                        /* 12: other 8 bytes of USER_LDT */
#define KERNEL_DS       0x68            /* 13: 32-bit kernel data */


#define SYSENTER_TF_CS  (USER_CS|0x10000)
#define SYSENTER_DS     KERNEL64_SS     /* sysenter kernel data segment */

#endif  /* _I386_SEG_H_ */
#ifdef __x86_64__
/*
 * 64-bit kernel LDT descriptors
 */
#define SYSCALL_CS      0x07            /* syscall pseudo-segment */
#define USER_CTHREAD    0x0f            /* user cthread area */
#define USER_SETTABLE   0x1f            /* start of user settable ldt entries */
#endif
Commit	Line	Data
1c79356b	1	/*
39236c6e	2	* Copyright (c) 2000-2012 Apple Inc. All rights reserved.
1c79356b	3	*
2d21ac55	4	* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
0a7de745	5	*
2d21ac55 A	6	* This file contains Original Code and/or Modifications of Original Code
	7	* as defined in and that are subject to the Apple Public Source License
	8	* Version 2.0 (the 'License'). You may not use this file except in
	9	* compliance with the License. The rights granted to you under the License
	10	* may not be used to create, or enable the creation or redistribution of,
	11	* unlawful or unlicensed copies of an Apple operating system, or to
	12	* circumvent, violate, or enable the circumvention or violation of, any
	13	* terms of an Apple operating system software license agreement.
0a7de745	14	*
2d21ac55 A	15	* Please obtain a copy of the License at
2d21ac55 A	16	* http://www.opensource.apple.com/apsl/ and read it before using this file.
0a7de745	17	*
2d21ac55 A	18	* The Original Code and all software distributed under the License are
2d21ac55 A	19	* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
8f6c56a5 A	20	* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
8f6c56a5 A	21	* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
2d21ac55 A	22	* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
	23	* Please see the License for the specific language governing rights and
	24	* limitations under the License.
0a7de745	25	*
2d21ac55	26	* @APPLE_OSREFERENCE_LICENSE_HEADER_END@
1c79356b A	27	*/
	28	/*
	29	* @OSF_COPYRIGHT@
	30	*/
0a7de745	31	/*
1c79356b A	32	* Mach Operating System
	33	* Copyright (c) 1991,1990 Carnegie Mellon University
	34	* All Rights Reserved.
0a7de745	35	*
1c79356b A	36	* Permission to use, copy, modify and distribute this software and its
	37	* documentation is hereby granted, provided that both the copyright
	38	* notice and this permission notice appear in all copies of the
	39	* software, derivative works or modified versions, and any portions
	40	* thereof, and that both notices appear in supporting documentation.
0a7de745	41	*
1c79356b A	42	* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
	43	* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
	44	* ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
0a7de745	45	*
1c79356b	46	* Carnegie Mellon requests users of this software to return to
0a7de745	47	*
1c79356b A	48	* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
	49	* School of Computer Science
	50	* Carnegie Mellon University
	51	* Pittsburgh PA 15213-3890
0a7de745	52	*
1c79356b A	53	* any improvements or extensions that they make and grant Carnegie Mellon
	54	* the rights to redistribute these changes.
	55	*/
0a7de745 A	56	#ifndef _I386_SEG_H_
0a7de745 A	57	#define _I386_SEG_H_
b0d623f7	58	#ifndef __ASSEMBLER__
91447636	59	#include <stdint.h>
0c530ab8	60	#include <mach/vm_types.h>
f427ee49	61	#include <mach/vm_param.h>
91447636	62	#include <architecture/i386/sel.h>
1c79356b A	63
	64	/*
	65	* i386 segmentation.
	66	*/
	67
91447636	68	static inline uint16_t
0a7de745	69	sel_to_selector(sel_t sel)
91447636	70	{
0a7de745 A	71	union {
	72	sel_t sel;
	73	uint16_t selector;
	74	} tconv;
	75
	76	tconv.sel = sel;
	77
	78	return tconv.selector;
91447636 A	79	}
	80
	81	static inline sel_t
	82	selector_to_sel(uint16_t selector)
	83	{
0a7de745 A	84	union {
	85	uint16_t selector;
	86	sel_t sel;
	87	} tconv;
	88
	89	tconv.selector = selector;
	90
	91	return tconv.sel;
91447636 A	92	}
91447636 A	93
0a7de745 A	94	#define LDTSZ_MAX 8192 /* maximal size of the kernel ldt in entries */
	95	#define LDTSZ_DFL (128)
	96	#define LDTSZ (LDTSZ_MAX)
	97	#define LDTSZ_MIN SEL_TO_INDEX(USER_SETTABLE)
	98	/* kernel ldt entries */
91447636	99
0a7de745	100	#define GDTSZ 19
91447636 A	101
	102	/*
	103	* Interrupt table is always 256 entries long.
	104	*/
0a7de745	105	#define IDTSZ 256
91447636	106
91447636 A	107	#include <sys/cdefs.h>
91447636 A	108
1c79356b A	109	/*
	110	* Real segment descriptor.
	111	*/
	112	struct real_descriptor {
0a7de745 A	113	uint32_t limit_low:16, /* limit 0..15 */
	114	base_low:16, /* base 0..15 */
	115	base_med:8, /* base 16..23 */
	116	access:8, /* access byte */
	117	limit_high:4, /* limit 16..19 */
	118	granularity:4, /* granularity */
	119	base_high:8; /* base 24..31 */
1c79356b	120	};
0c530ab8	121	struct real_descriptor64 {
0a7de745 A	122	uint32_t limit_low16:16, /* limit 0..15 */
	123	base_low16:16, /* base 0..15 */
	124	base_med8:8, /* base 16..23 */
	125	access8:8, /* access byte */
	126	limit_high4:4, /* limit 16..19 */
	127	granularity4:4, /* granularity */
	128	base_high8:8, /* base 24..31 */
	129	base_top32:32, /* base 32..63 */
	130	reserved32:32; /* reserved/zero */
0c530ab8	131	};
1c79356b	132	struct real_gate {
0a7de745 A	133	uint32_t offset_low:16, /* offset 0..15 */
	134	selector:16,
	135	word_count:8,
	136	access:8,
	137	offset_high:16; /* offset 16..31 */
1c79356b	138	};
0c530ab8	139	struct real_gate64 {
0a7de745 A	140	uint32_t offset_low16:16, /* offset 0..15 */
	141	selector16:16,
	142	IST:3,
	143	zeroes5:5,
	144	access8:8,
	145	offset_high16:16, /* offset 16..31 */
	146	offset_top32:32, /* offset 32..63 */
	147	reserved32:32; /* reserved/zero */
0c530ab8	148	};
1c79356b	149
0a7de745	150	#define MAKE_REAL_DESCRIPTOR(base, lim, gran, acc) {\
b0d623f7 A	151	.limit_low = lim & 0xffff, \
	152	.limit_high = (lim >> 16) & 0xf, \
	153	.base_low = base & 0xffff, \
	154	.base_med = (base >> 16) & 0xff, \
	155	.base_high = (base >> 24) & 0xff, \
	156	.access = acc, \
	157	.granularity = gran \
	158	}
	159
1c79356b A	160	/*
	161	* We build descriptors and gates in a 'fake' format to let the
	162	* fields be contiguous. We shuffle them into the real format
	163	* at runtime.
	164	*/
	165	struct fake_descriptor {
0a7de745 A	166	uint32_t offset:32; /* offset */
	167	uint32_t lim_or_seg:20; /* limit */
	168	/* or segment, for gate */
	169	uint32_t size_or_wdct:4; /* size/granularity */
	170	/* word count, for gate */
	171	uint32_t access:8; /* access */
4452a7af	172	};
0c530ab8	173	struct fake_descriptor64 {
0a7de745 A	174	uint64_t offset64; /* offset [0..31,32..63] */
	175	uint32_t lim_or_seg:20; /* limit */
	176	/* or segment, for gate */
	177	uint32_t size_or_IST:4; /* size/granularity */
	178	/* IST for gates */
	179	uint32_t access:8; /* access */
	180	uint32_t reserved:32; /* reserved/zero */
0c530ab8	181	};
91447636	182
5ba3f43e	183	typedef struct __attribute__((packed)) {
0a7de745 A	184	uint16_t size;
0a7de745 A	185	void *ptr;
5ba3f43e A	186	} x86_64_desc_register_t;
5ba3f43e A	187
5c9f4661 A	188
5c9f4661 A	189
91447636 A	190	/*
	191	* Boot-time data for master (or only) CPU
	192	*/
0a7de745 A	193	extern struct real_descriptor master_gdt[GDTSZ];
	194	extern struct real_descriptor master_ldt[];
	195	extern struct i386_tss master_ktss;
	196	extern struct sysenter_stack master_sstk;
0c530ab8	197
0a7de745 A	198	extern struct fake_descriptor64 master_idt64[IDTSZ];
0a7de745 A	199	extern struct x86_64_tss master_ktss64;
91447636 A	200
	201	__BEGIN_DECLS
	202
0a7de745 A	203	extern char df_task_stack[];
	204	extern char df_task_stack_end[];
	205	extern struct i386_tss master_dftss;
	206	extern void df_task_start(void);
0c530ab8	207
0a7de745 A	208	extern char mc_task_stack[];
	209	extern char mc_task_stack_end[];
	210	extern struct i386_tss master_mctss;
	211	extern void mc_task_start(void);
0c530ab8	212
91447636 A	213	__END_DECLS
91447636 A	214
0a7de745	215	#endif /__ASSEMBLER__/
1c79356b	216
0a7de745 A	217	#define SZ_64 0x2 /* 64-bit segment */
	218	#define SZ_32 0x4 /* 32-bit segment */
	219	#define SZ_G 0x8 /* 4K limit field */
1c79356b	220
0a7de745 A	221	#define ACC_A 0x01 /* accessed */
0a7de745 A	222	#define ACC_TYPE 0x1e /* type field: */
1c79356b	223
0a7de745	224	#define ACC_TYPE_SYSTEM 0x00 /* system descriptors: */
1c79356b	225
0a7de745 A	226	#define ACC_LDT 0x02 /* LDT */
	227	#define ACC_CALL_GATE_16 0x04 /* 16-bit call gate */
	228	#define ACC_TASK_GATE 0x05 /* task gate */
	229	#define ACC_TSS 0x09 /* task segment */
	230	#define ACC_CALL_GATE 0x0c /* call gate */
	231	#define ACC_INTR_GATE 0x0e /* interrupt gate */
	232	#define ACC_TRAP_GATE 0x0f /* trap gate */
1c79356b	233
0a7de745	234	#define ACC_TSS_BUSY 0x02 /* task busy */
1c79356b	235
0a7de745	236	#define ACC_TYPE_USER 0x10 /* user descriptors */
1c79356b	237
0a7de745 A	238	#define ACC_DATA 0x10 /* data */
	239	#define ACC_DATA_W 0x12 /* data, writable */
	240	#define ACC_DATA_E 0x14 /* data, expand-down */
	241	#define ACC_DATA_EW 0x16 /* data, expand-down,
	242	* writable */
	243	#define ACC_CODE 0x18 /* code */
	244	#define ACC_CODE_R 0x1a /* code, readable */
	245	#define ACC_CODE_C 0x1c /* code, conforming */
	246	#define ACC_CODE_CR 0x1e /* code, conforming,
	247	* readable */
	248	#define ACC_PL 0x60 /* access rights: */
	249	#define ACC_PL_K 0x00 /* kernel access only */
	250	#define ACC_PL_U 0x60 /* user access */
	251	#define ACC_P 0x80 /* segment present */
1c79356b A	252
	253	/*
	254	* Components of a selector
	255	*/
0a7de745 A	256	#define SEL_LDTS 0x04 /* local selector */
	257	#define SEL_PL 0x03 /* privilege level: */
	258	#define SEL_PL_K 0x00 /* kernel selector */
	259	#define SEL_PL_U 0x03 /* user selector */
1c79356b A	260
	261	/*
	262	* Convert selector to descriptor table index.
	263	*/
0a7de745 A	264	#define sel_idx(sel) (selector_to_sel(sel).index)
0a7de745 A	265	#define SEL_TO_INDEX(s) ((s)>>3)
91447636	266
0a7de745	267	#define NULL_SEG 0
1c79356b	268
0c530ab8	269
b0d623f7 A	270	/*
	271	* Kernel descriptors for MACH - 64-bit flat address space.
	272	*/
0a7de745 A	273	#define KERNEL64_CS 0x08 /* 1: K64 code */
	274	#define SYSENTER_CS 0x0b /* U32 sysenter pseudo-segment */
	275	#define KERNEL64_SS 0x10 /* 2: KERNEL64_CS+8 for syscall */
	276	#define USER_CS 0x1b /* 3: U32 code */
	277	#define USER_DS 0x23 /* 4: USER_CS+8 for sysret */
	278	#define USER64_CS 0x2b /* 5: USER_CS+16 for sysret */
	279	#define USER64_DS USER_DS /* U64 data pseudo-segment */
	280	#define KERNEL_LDT 0x30 /* 6: */
	281	/* 7: other 8 bytes of KERNEL_LDT */
	282	#define KERNEL_TSS 0x40 /* 8: */
	283	/* 9: other 8 bytes of KERNEL_TSS */
	284	#define KERNEL32_CS 0x50 /* 10: */
	285	#define USER_LDT 0x58 /* 11: */
	286	/* 12: other 8 bytes of USER_LDT */
	287	#define KERNEL_DS 0x68 /* 13: 32-bit kernel data */
	288
	289
	290	#define SYSENTER_TF_CS (USER_CS\|0x10000)
	291	#define SYSENTER_DS KERNEL64_SS /* sysenter kernel data segment */
	292
	293	#endif /* _I386_SEG_H_ */
b0d623f7 A	294	#ifdef __x86_64__
	295	/*
	296	* 64-bit kernel LDT descriptors
	297	*/
0a7de745 A	298	#define SYSCALL_CS 0x07 /* syscall pseudo-segment */
	299	#define USER_CTHREAD 0x0f /* user cthread area */
	300	#define USER_SETTABLE 0x1f /* start of user settable ldt entries */
b0d623f7	301	#endif