[deliverable/linux.git] / arch / x86 / include / asm / segment.h

#ifndef _ASM_X86_SEGMENT_H
#define _ASM_X86_SEGMENT_H

#include <linux/const.h>

/* Constructor for a conventional segment GDT (or LDT) entry */
/* This is a macro so it can be used in initializers */
#define GDT_ENTRY(flags, base, limit)			\
	((((base)  & _AC(0xff000000,ULL)) << (56-24)) |	\
	 (((flags) & _AC(0x0000f0ff,ULL)) << 40) |	\
	 (((limit) & _AC(0x000f0000,ULL)) << (48-16)) |	\
	 (((base)  & _AC(0x00ffffff,ULL)) << 16) |	\
	 (((limit) & _AC(0x0000ffff,ULL))))

/* Simple and small GDT entries for booting only */

#define GDT_ENTRY_BOOT_CS	2
#define __BOOT_CS		(GDT_ENTRY_BOOT_CS * 8)

#define GDT_ENTRY_BOOT_DS	(GDT_ENTRY_BOOT_CS + 1)
#define __BOOT_DS		(GDT_ENTRY_BOOT_DS * 8)

#define GDT_ENTRY_BOOT_TSS	(GDT_ENTRY_BOOT_CS + 2)
#define __BOOT_TSS		(GDT_ENTRY_BOOT_TSS * 8)

#ifdef CONFIG_X86_32
/*
 * The layout of the per-CPU GDT under Linux:
 *
 *   0 - null
 *   1 - reserved
 *   2 - reserved
 *   3 - reserved
 *
 *   4 - unused			<==== new cacheline
 *   5 - unused
 *
 *  ------- start of TLS (Thread-Local Storage) segments:
 *
 *   6 - TLS segment #1			[ glibc's TLS segment ]
 *   7 - TLS segment #2			[ Wine's %fs Win32 segment ]
 *   8 - TLS segment #3
 *   9 - reserved
 *  10 - reserved
 *  11 - reserved
 *
 *  ------- start of kernel segments:
 *
 *  12 - kernel code segment		<==== new cacheline
 *  13 - kernel data segment
 *  14 - default user CS
 *  15 - default user DS
 *  16 - TSS
 *  17 - LDT
 *  18 - PNPBIOS support (16->32 gate)
 *  19 - PNPBIOS support
 *  20 - PNPBIOS support
 *  21 - PNPBIOS support
 *  22 - PNPBIOS support
 *  23 - APM BIOS support
 *  24 - APM BIOS support
 *  25 - APM BIOS support
 *
 *  26 - ESPFIX small SS
 *  27 - per-cpu			[ offset to per-cpu data area ]
 *  28 - stack_canary-20		[ for stack protector ]
 *  29 - unused
 *  30 - unused
 *  31 - TSS for double fault handler
 */
#define GDT_ENTRY_TLS_MIN	6
#define GDT_ENTRY_TLS_MAX 	(GDT_ENTRY_TLS_MIN + GDT_ENTRY_TLS_ENTRIES - 1)

#define GDT_ENTRY_DEFAULT_USER_CS	14

#define GDT_ENTRY_DEFAULT_USER_DS	15

#define GDT_ENTRY_KERNEL_BASE		(12)

#define GDT_ENTRY_KERNEL_CS		(GDT_ENTRY_KERNEL_BASE+0)

#define GDT_ENTRY_KERNEL_DS		(GDT_ENTRY_KERNEL_BASE+1)

#define GDT_ENTRY_TSS			(GDT_ENTRY_KERNEL_BASE+4)
#define GDT_ENTRY_LDT			(GDT_ENTRY_KERNEL_BASE+5)

#define GDT_ENTRY_PNPBIOS_BASE		(GDT_ENTRY_KERNEL_BASE+6)
#define GDT_ENTRY_APMBIOS_BASE		(GDT_ENTRY_KERNEL_BASE+11)

#define GDT_ENTRY_ESPFIX_SS		(GDT_ENTRY_KERNEL_BASE+14)
#define __ESPFIX_SS			(GDT_ENTRY_ESPFIX_SS*8)

#define GDT_ENTRY_PERCPU		(GDT_ENTRY_KERNEL_BASE+15)
#ifdef CONFIG_SMP
#define __KERNEL_PERCPU (GDT_ENTRY_PERCPU * 8)
#else
#define __KERNEL_PERCPU 0
#endif

#define GDT_ENTRY_STACK_CANARY		(GDT_ENTRY_KERNEL_BASE+16)
#ifdef CONFIG_CC_STACKPROTECTOR
#define __KERNEL_STACK_CANARY		(GDT_ENTRY_STACK_CANARY*8)
#else
#define __KERNEL_STACK_CANARY		0
#endif

#define GDT_ENTRY_DOUBLEFAULT_TSS	31

/*
 * The GDT has 32 entries
 */
#define GDT_ENTRIES 32

/* The PnP BIOS entries in the GDT */
#define GDT_ENTRY_PNPBIOS_CS32		(GDT_ENTRY_PNPBIOS_BASE + 0)
#define GDT_ENTRY_PNPBIOS_CS16		(GDT_ENTRY_PNPBIOS_BASE + 1)
#define GDT_ENTRY_PNPBIOS_DS		(GDT_ENTRY_PNPBIOS_BASE + 2)
#define GDT_ENTRY_PNPBIOS_TS1		(GDT_ENTRY_PNPBIOS_BASE + 3)
#define GDT_ENTRY_PNPBIOS_TS2		(GDT_ENTRY_PNPBIOS_BASE + 4)

/* The PnP BIOS selectors */
#define PNP_CS32   (GDT_ENTRY_PNPBIOS_CS32 * 8)	/* segment for calling fn */
#define PNP_CS16   (GDT_ENTRY_PNPBIOS_CS16 * 8)	/* code segment for BIOS */
#define PNP_DS     (GDT_ENTRY_PNPBIOS_DS * 8)	/* data segment for BIOS */
#define PNP_TS1    (GDT_ENTRY_PNPBIOS_TS1 * 8)	/* transfer data segment */
#define PNP_TS2    (GDT_ENTRY_PNPBIOS_TS2 * 8)	/* another data segment */

/* Bottom two bits of selector give the ring privilege level */
#define SEGMENT_RPL_MASK	0x3
/* Bit 2 is table indicator (LDT/GDT) */
#define SEGMENT_TI_MASK		0x4

/* User mode is privilege level 3 */
#define USER_RPL		0x3
/* LDT segment has TI set, GDT has it cleared */
#define SEGMENT_LDT		0x4
#define SEGMENT_GDT		0x0

/*
 * Matching rules for certain types of segments.
 */

/* Matches PNP_CS32 and PNP_CS16 (they must be consecutive) */
#define SEGMENT_IS_PNP_CODE(x)   (((x) & 0xf4) == GDT_ENTRY_PNPBIOS_BASE * 8)


#else
#include <asm/cache.h>

#define GDT_ENTRY_KERNEL32_CS 1
#define GDT_ENTRY_KERNEL_CS 2
#define GDT_ENTRY_KERNEL_DS 3

#define __KERNEL32_CS   (GDT_ENTRY_KERNEL32_CS * 8)

/*
 * we cannot use the same code segment descriptor for user and kernel
 * -- not even in the long flat mode, because of different DPL /kkeil
 * The segment offset needs to contain a RPL. Grr. -AK
 * GDT layout to get 64bit syscall right (sysret hardcodes gdt offsets)
 */
#define GDT_ENTRY_DEFAULT_USER32_CS 4
#define GDT_ENTRY_DEFAULT_USER_DS 5
#define GDT_ENTRY_DEFAULT_USER_CS 6
#define __USER32_CS   (GDT_ENTRY_DEFAULT_USER32_CS*8+3)
#define __USER32_DS	__USER_DS

#define GDT_ENTRY_TSS 8	/* needs two entries */
#define GDT_ENTRY_LDT 10 /* needs two entries */
#define GDT_ENTRY_TLS_MIN 12
#define GDT_ENTRY_TLS_MAX 14

#define GDT_ENTRY_PER_CPU 15	/* Abused to load per CPU data from limit */
#define __PER_CPU_SEG	(GDT_ENTRY_PER_CPU * 8 + 3)

/* TLS indexes for 64bit - hardcoded in arch_prctl */
#define FS_TLS 0
#define GS_TLS 1

#define GS_TLS_SEL ((GDT_ENTRY_TLS_MIN+GS_TLS)*8 + 3)
#define FS_TLS_SEL ((GDT_ENTRY_TLS_MIN+FS_TLS)*8 + 3)

#define GDT_ENTRIES 16

#endif

#define __KERNEL_CS	(GDT_ENTRY_KERNEL_CS*8)
#define __KERNEL_DS	(GDT_ENTRY_KERNEL_DS*8)
#define __USER_DS	(GDT_ENTRY_DEFAULT_USER_DS*8+3)
#define __USER_CS	(GDT_ENTRY_DEFAULT_USER_CS*8+3)
#ifndef CONFIG_PARAVIRT
#define get_kernel_rpl()  0
#endif

/* User mode is privilege level 3 */
#define USER_RPL		0x3
/* LDT segment has TI set, GDT has it cleared */
#define SEGMENT_LDT		0x4
#define SEGMENT_GDT		0x0

/* Bottom two bits of selector give the ring privilege level */
#define SEGMENT_RPL_MASK	0x3
/* Bit 2 is table indicator (LDT/GDT) */
#define SEGMENT_TI_MASK		0x4

#define IDT_ENTRIES 256
#define NUM_EXCEPTION_VECTORS 32
/* Bitmask of exception vectors which push an error code on the stack */
#define EXCEPTION_ERRCODE_MASK  0x00027d00
#define GDT_SIZE (GDT_ENTRIES * 8)
#define GDT_ENTRY_TLS_ENTRIES 3
#define TLS_SIZE (GDT_ENTRY_TLS_ENTRIES * 8)

#ifdef __KERNEL__
#ifndef __ASSEMBLY__
extern const char early_idt_handlers[NUM_EXCEPTION_VECTORS][2+2+5];
#ifdef CONFIG_TRACING
#define trace_early_idt_handlers early_idt_handlers
#endif

/*
 * Load a segment. Fall back on loading the zero
 * segment if something goes wrong..
 */
#define loadsegment(seg, value)						\
do {									\
	unsigned short __val = (value);					\
									\
	asm volatile("						\n"	\
		     "1:	movl %k0,%%" #seg "		\n"	\
									\
		     ".section .fixup,\"ax\"			\n"	\
		     "2:	xorl %k0,%k0			\n"	\
		     "		jmp 1b				\n"	\
		     ".previous					\n"	\
									\
		     _ASM_EXTABLE(1b, 2b)				\
									\
		     : "+r" (__val) : : "memory");			\
} while (0)

/*
 * Save a segment register away
 */
#define savesegment(seg, value)				\
	asm("mov %%" #seg ",%0":"=r" (value) : : "memory")

/*
 * x86_32 user gs accessors.
 */
#ifdef CONFIG_X86_32
#ifdef CONFIG_X86_32_LAZY_GS
#define get_user_gs(regs)	(u16)({unsigned long v; savesegment(gs, v); v;})
#define set_user_gs(regs, v)	loadsegment(gs, (unsigned long)(v))
#define task_user_gs(tsk)	((tsk)->thread.gs)
#define lazy_save_gs(v)		savesegment(gs, (v))
#define lazy_load_gs(v)		loadsegment(gs, (v))
#else	/* X86_32_LAZY_GS */
#define get_user_gs(regs)	(u16)((regs)->gs)
#define set_user_gs(regs, v)	do { (regs)->gs = (v); } while (0)
#define task_user_gs(tsk)	(task_pt_regs(tsk)->gs)
#define lazy_save_gs(v)		do { } while (0)
#define lazy_load_gs(v)		do { } while (0)
#endif	/* X86_32_LAZY_GS */
#endif	/* X86_32 */

static inline unsigned long get_limit(unsigned long segment)
{
	unsigned long __limit;
	asm("lsll %1,%0" : "=r" (__limit) : "r" (segment));
	return __limit + 1;
}

#endif /* !__ASSEMBLY__ */
#endif /* __KERNEL__ */

#endif /* _ASM_X86_SEGMENT_H */
Commit	Line	Data
1965aae3 PA	1	#ifndef _ASM_X86_SEGMENT_H
1965aae3 PA	2	#define _ASM_X86_SEGMENT_H
cef18950	3
014eea51 PA	4	#include <linux/const.h>
014eea51 PA	5
4fdf08b5 PA	6	/* Constructor for a conventional segment GDT (or LDT) entry */
	7	/* This is a macro so it can be used in initializers */
	8	#define GDT_ENTRY(flags, base, limit) \
014eea51 PA	9	((((base) & _AC(0xff000000,ULL)) << (56-24)) \| \
	10	(((flags) & _AC(0x0000f0ff,ULL)) << 40) \| \
	11	(((limit) & _AC(0x000f0000,ULL)) << (48-16)) \| \
	12	(((base) & _AC(0x00ffffff,ULL)) << 16) \| \
	13	(((limit) & _AC(0x0000ffff,ULL))))
4fdf08b5	14
2a6648e6 PA	15	/* Simple and small GDT entries for booting only */
	16
	17	#define GDT_ENTRY_BOOT_CS 2
	18	#define __BOOT_CS (GDT_ENTRY_BOOT_CS * 8)
	19
	20	#define GDT_ENTRY_BOOT_DS (GDT_ENTRY_BOOT_CS + 1)
	21	#define __BOOT_DS (GDT_ENTRY_BOOT_DS * 8)
	22
88089519 PA	23	#define GDT_ENTRY_BOOT_TSS (GDT_ENTRY_BOOT_CS + 2)
	24	#define __BOOT_TSS (GDT_ENTRY_BOOT_TSS * 8)
	25
96a388de	26	#ifdef CONFIG_X86_32
b23be399 GOC	27	/*
	28	* The layout of the per-CPU GDT under Linux:
	29	*
	30	* 0 - null
	31	* 1 - reserved
	32	* 2 - reserved
	33	* 3 - reserved
	34	*
	35	* 4 - unused <==== new cacheline
	36	* 5 - unused
	37	*
	38	* ------- start of TLS (Thread-Local Storage) segments:
	39	*
	40	* 6 - TLS segment #1 [ glibc's TLS segment ]
	41	* 7 - TLS segment #2 [ Wine's %fs Win32 segment ]
	42	* 8 - TLS segment #3
	43	* 9 - reserved
	44	* 10 - reserved
	45	* 11 - reserved
	46	*
	47	* ------- start of kernel segments:
	48	*
	49	* 12 - kernel code segment <==== new cacheline
	50	* 13 - kernel data segment
	51	* 14 - default user CS
	52	* 15 - default user DS
	53	* 16 - TSS
	54	* 17 - LDT
	55	* 18 - PNPBIOS support (16->32 gate)
	56	* 19 - PNPBIOS support
	57	* 20 - PNPBIOS support
	58	* 21 - PNPBIOS support
	59	* 22 - PNPBIOS support
	60	* 23 - APM BIOS support
	61	* 24 - APM BIOS support
	62	* 25 - APM BIOS support
	63	*
	64	* 26 - ESPFIX small SS
	65	* 27 - per-cpu [ offset to per-cpu data area ]
60a5317f	66	* 28 - stack_canary-20 [ for stack protector ]
b23be399 GOC	67	* 29 - unused
	68	* 30 - unused
	69	* 31 - TSS for double fault handler
	70	*/
	71	#define GDT_ENTRY_TLS_MIN 6
	72	#define GDT_ENTRY_TLS_MAX (GDT_ENTRY_TLS_MIN + GDT_ENTRY_TLS_ENTRIES - 1)
	73
	74	#define GDT_ENTRY_DEFAULT_USER_CS 14
b23be399 GOC	75
b23be399 GOC	76	#define GDT_ENTRY_DEFAULT_USER_DS 15
b23be399	77
3234282f	78	#define GDT_ENTRY_KERNEL_BASE (12)
b23be399	79
3234282f	80	#define GDT_ENTRY_KERNEL_CS (GDT_ENTRY_KERNEL_BASE+0)
b23be399	81
3234282f	82	#define GDT_ENTRY_KERNEL_DS (GDT_ENTRY_KERNEL_BASE+1)
b23be399	83
3234282f JB	84	#define GDT_ENTRY_TSS (GDT_ENTRY_KERNEL_BASE+4)
3234282f JB	85	#define GDT_ENTRY_LDT (GDT_ENTRY_KERNEL_BASE+5)
b23be399	86
3234282f JB	87	#define GDT_ENTRY_PNPBIOS_BASE (GDT_ENTRY_KERNEL_BASE+6)
3234282f JB	88	#define GDT_ENTRY_APMBIOS_BASE (GDT_ENTRY_KERNEL_BASE+11)
b23be399	89
3234282f JB	90	#define GDT_ENTRY_ESPFIX_SS (GDT_ENTRY_KERNEL_BASE+14)
3234282f JB	91	#define __ESPFIX_SS (GDT_ENTRY_ESPFIX_SS*8)
b23be399	92
3234282f	93	#define GDT_ENTRY_PERCPU (GDT_ENTRY_KERNEL_BASE+15)
b23be399 GOC	94	#ifdef CONFIG_SMP
	95	#define __KERNEL_PERCPU (GDT_ENTRY_PERCPU * 8)
	96	#else
	97	#define __KERNEL_PERCPU 0
	98	#endif
	99
3234282f	100	#define GDT_ENTRY_STACK_CANARY (GDT_ENTRY_KERNEL_BASE+16)
60a5317f	101	#ifdef CONFIG_CC_STACKPROTECTOR
3234282f	102	#define __KERNEL_STACK_CANARY (GDT_ENTRY_STACK_CANARY*8)
60a5317f TH	103	#else
	104	#define __KERNEL_STACK_CANARY 0
	105	#endif
	106
b23be399 GOC	107	#define GDT_ENTRY_DOUBLEFAULT_TSS 31
	108
	109	/*
	110	* The GDT has 32 entries
	111	*/
	112	#define GDT_ENTRIES 32
	113
b23be399 GOC	114	/* The PnP BIOS entries in the GDT */
	115	#define GDT_ENTRY_PNPBIOS_CS32 (GDT_ENTRY_PNPBIOS_BASE + 0)
	116	#define GDT_ENTRY_PNPBIOS_CS16 (GDT_ENTRY_PNPBIOS_BASE + 1)
	117	#define GDT_ENTRY_PNPBIOS_DS (GDT_ENTRY_PNPBIOS_BASE + 2)
	118	#define GDT_ENTRY_PNPBIOS_TS1 (GDT_ENTRY_PNPBIOS_BASE + 3)
	119	#define GDT_ENTRY_PNPBIOS_TS2 (GDT_ENTRY_PNPBIOS_BASE + 4)
	120
	121	/* The PnP BIOS selectors */
	122	#define PNP_CS32 (GDT_ENTRY_PNPBIOS_CS32 * 8) /* segment for calling fn */
	123	#define PNP_CS16 (GDT_ENTRY_PNPBIOS_CS16 * 8) /* code segment for BIOS */
	124	#define PNP_DS (GDT_ENTRY_PNPBIOS_DS * 8) /* data segment for BIOS */
	125	#define PNP_TS1 (GDT_ENTRY_PNPBIOS_TS1 * 8) /* transfer data segment */
	126	#define PNP_TS2 (GDT_ENTRY_PNPBIOS_TS2 * 8) /* another data segment */
	127
	128	/* Bottom two bits of selector give the ring privilege level */
	129	#define SEGMENT_RPL_MASK 0x3
	130	/* Bit 2 is table indicator (LDT/GDT) */
	131	#define SEGMENT_TI_MASK 0x4
	132
	133	/* User mode is privilege level 3 */
	134	#define USER_RPL 0x3
	135	/* LDT segment has TI set, GDT has it cleared */
	136	#define SEGMENT_LDT 0x4
	137	#define SEGMENT_GDT 0x0
	138
	139	/*
	140	* Matching rules for certain types of segments.
	141	*/
	142
b23be399 GOC	143	/* Matches PNP_CS32 and PNP_CS16 (they must be consecutive) */
	144	#define SEGMENT_IS_PNP_CODE(x) (((x) & 0xf4) == GDT_ENTRY_PNPBIOS_BASE * 8)
	145
	146
96a388de	147	#else
b23be399 GOC	148	#include <asm/cache.h>
b23be399 GOC	149
a939098a GC	150	#define GDT_ENTRY_KERNEL32_CS 1
	151	#define GDT_ENTRY_KERNEL_CS 2
	152	#define GDT_ENTRY_KERNEL_DS 3
b23be399	153
a939098a	154	#define __KERNEL32_CS (GDT_ENTRY_KERNEL32_CS * 8)
b23be399 GOC	155
	156	/*
	157	* we cannot use the same code segment descriptor for user and kernel
	158	* -- not even in the long flat mode, because of different DPL /kkeil
	159	* The segment offset needs to contain a RPL. Grr. -AK
	160	* GDT layout to get 64bit syscall right (sysret hardcodes gdt offsets)
	161	*/
a939098a GC	162	#define GDT_ENTRY_DEFAULT_USER32_CS 4
	163	#define GDT_ENTRY_DEFAULT_USER_DS 5
	164	#define GDT_ENTRY_DEFAULT_USER_CS 6
dd2897bf	165	#define __USER32_CS (GDT_ENTRY_DEFAULT_USER32_CS*8+3)
b23be399 GOC	166	#define __USER32_DS __USER_DS
	167
	168	#define GDT_ENTRY_TSS 8 /* needs two entries */
	169	#define GDT_ENTRY_LDT 10 /* needs two entries */
	170	#define GDT_ENTRY_TLS_MIN 12
	171	#define GDT_ENTRY_TLS_MAX 14
	172
	173	#define GDT_ENTRY_PER_CPU 15 /* Abused to load per CPU data from limit */
	174	#define __PER_CPU_SEG (GDT_ENTRY_PER_CPU * 8 + 3)
	175
	176	/* TLS indexes for 64bit - hardcoded in arch_prctl */
	177	#define FS_TLS 0
	178	#define GS_TLS 1
	179
	180	#define GS_TLS_SEL ((GDT_ENTRY_TLS_MIN+GS_TLS)*8 + 3)
	181	#define FS_TLS_SEL ((GDT_ENTRY_TLS_MIN+FS_TLS)*8 + 3)
	182
	183	#define GDT_ENTRIES 16
	184
96a388de	185	#endif
cef18950	186
3234282f JB	187	#define __KERNEL_CS (GDT_ENTRY_KERNEL_CS*8)
	188	#define __KERNEL_DS (GDT_ENTRY_KERNEL_DS*8)
	189	#define __USER_DS (GDT_ENTRY_DEFAULT_USER_DS*8+3)
	190	#define __USER_CS (GDT_ENTRY_DEFAULT_USER_CS*8+3)
cef18950 GOC	191	#ifndef CONFIG_PARAVIRT
	192	#define get_kernel_rpl() 0
	193	#endif
	194
15ee09b4 GOC	195	/* User mode is privilege level 3 */
	196	#define USER_RPL 0x3
	197	/* LDT segment has TI set, GDT has it cleared */
	198	#define SEGMENT_LDT 0x4
	199	#define SEGMENT_GDT 0x0
	200
	201	/* Bottom two bits of selector give the ring privilege level */
	202	#define SEGMENT_RPL_MASK 0x3
	203	/* Bit 2 is table indicator (LDT/GDT) */
	204	#define SEGMENT_TI_MASK 0x4
	205
	206	#define IDT_ENTRIES 256
5524ea32	207	#define NUM_EXCEPTION_VECTORS 32
84f4fc52 PA	208	/* Bitmask of exception vectors which push an error code on the stack */
84f4fc52 PA	209	#define EXCEPTION_ERRCODE_MASK 0x00027d00
15ee09b4 GOC	210	#define GDT_SIZE (GDT_ENTRIES * 8)
	211	#define GDT_ENTRY_TLS_ENTRIES 3
	212	#define TLS_SIZE (GDT_ENTRY_TLS_ENTRIES * 8)
	213
8866cd9d RM	214	#ifdef __KERNEL__
8866cd9d RM	215	#ifndef __ASSEMBLY__
9900aa2f	216	extern const char early_idt_handlers[NUM_EXCEPTION_VECTORS][2+2+5];
25c74b10 SA	217	#ifdef CONFIG_TRACING
	218	#define trace_early_idt_handlers early_idt_handlers
	219	#endif
f05e798a DH	220
	221	/*
	222	* Load a segment. Fall back on loading the zero
	223	* segment if something goes wrong..
	224	*/
	225	#define loadsegment(seg, value) \
	226	do { \
	227	unsigned short __val = (value); \
	228	\
	229	asm volatile(" \n" \
	230	"1: movl %k0,%%" #seg " \n" \
	231	\
	232	".section .fixup,\"ax\" \n" \
	233	"2: xorl %k0,%k0 \n" \
	234	" jmp 1b \n" \
	235	".previous \n" \
	236	\
	237	_ASM_EXTABLE(1b, 2b) \
	238	\
	239	: "+r" (__val) : : "memory"); \
	240	} while (0)
	241
	242	/*
	243	* Save a segment register away
	244	*/
	245	#define savesegment(seg, value) \
	246	asm("mov %%" #seg ",%0":"=r" (value) : : "memory")
	247
	248	/*
	249	* x86_32 user gs accessors.
	250	*/
	251	#ifdef CONFIG_X86_32
	252	#ifdef CONFIG_X86_32_LAZY_GS
	253	#define get_user_gs(regs) (u16)({unsigned long v; savesegment(gs, v); v;})
	254	#define set_user_gs(regs, v) loadsegment(gs, (unsigned long)(v))
	255	#define task_user_gs(tsk) ((tsk)->thread.gs)
	256	#define lazy_save_gs(v) savesegment(gs, (v))
	257	#define lazy_load_gs(v) loadsegment(gs, (v))
	258	#else /* X86_32_LAZY_GS */
	259	#define get_user_gs(regs) (u16)((regs)->gs)
	260	#define set_user_gs(regs, v) do { (regs)->gs = (v); } while (0)
	261	#define task_user_gs(tsk) (task_pt_regs(tsk)->gs)
	262	#define lazy_save_gs(v) do { } while (0)
	263	#define lazy_load_gs(v) do { } while (0)
	264	#endif /* X86_32_LAZY_GS */
	265	#endif /* X86_32 */
	266
	267	static inline unsigned long get_limit(unsigned long segment)
	268	{
	269	unsigned long __limit;
	270	asm("lsll %1,%0" : "=r" (__limit) : "r" (segment));
	271	return __limit + 1;
	272	}
	273
	274	#endif /* !__ASSEMBLY__ */
	275	#endif /* __KERNEL__ */
8866cd9d	276
1965aae3	277	#endif /* _ASM_X86_SEGMENT_H */