[mirror_ubuntu-bionic-kernel.git] / arch / x86 / include / asm / segment.h

#ifndef _ASM_X86_SEGMENT_H
#define _ASM_X86_SEGMENT_H

#include <linux/const.h>
#include <asm/alternative.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 GDT_ENTRY_BOOT_DS	3
#define GDT_ENTRY_BOOT_TSS	4
#define __BOOT_CS		(GDT_ENTRY_BOOT_CS*8)
#define __BOOT_DS		(GDT_ENTRY_BOOT_DS*8)
#define __BOOT_TSS		(GDT_ENTRY_BOOT_TSS*8)

/*
 * Bottom two bits of selector give the ring
 * privilege level
 */
#define SEGMENT_RPL_MASK	0x3

/* User mode is privilege level 3: */
#define USER_RPL		0x3

/* Bit 2 is Table Indicator (TI): selects between LDT or GDT */
#define SEGMENT_TI_MASK		0x4
/* LDT segment has TI set ... */
#define SEGMENT_LDT		0x4
/* ... GDT has it cleared */
#define SEGMENT_GDT		0x0

#define GDT_ENTRY_INVALID_SEG	0

#ifdef CONFIG_X86_32
/*
 * The layout of the per-CPU GDT under Linux:
 *
 *   0 - null								<=== cacheline #1
 *   1 - reserved
 *   2 - reserved
 *   3 - reserved
 *
 *   4 - unused								<=== cacheline #2
 *   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							<=== cacheline #3
 *   9 - reserved
 *  10 - reserved
 *  11 - reserved
 *
 *  ------- start of kernel segments:
 *
 *  12 - kernel code segment						<=== cacheline #4
 *  13 - kernel data segment
 *  14 - default user CS
 *  15 - default user DS
 *  16 - TSS								<=== cacheline #5
 *  17 - LDT
 *  18 - PNPBIOS support (16->32 gate)
 *  19 - PNPBIOS support
 *  20 - PNPBIOS support						<=== cacheline #6
 *  21 - PNPBIOS support
 *  22 - PNPBIOS support
 *  23 - APM BIOS support
 *  24 - APM BIOS support						<=== cacheline #7
 *  25 - APM BIOS support
 *
 *  26 - ESPFIX small SS
 *  27 - per-cpu			[ offset to per-cpu data area ]
 *  28 - stack_canary-20		[ for stack protector ]		<=== cacheline #8
 *  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_KERNEL_CS		12
#define GDT_ENTRY_KERNEL_DS		13
#define GDT_ENTRY_DEFAULT_USER_CS	14
#define GDT_ENTRY_DEFAULT_USER_DS	15
#define GDT_ENTRY_TSS			16
#define GDT_ENTRY_LDT			17
#define GDT_ENTRY_PNPBIOS_CS32		18
#define GDT_ENTRY_PNPBIOS_CS16		19
#define GDT_ENTRY_PNPBIOS_DS		20
#define GDT_ENTRY_PNPBIOS_TS1		21
#define GDT_ENTRY_PNPBIOS_TS2		22
#define GDT_ENTRY_APMBIOS_BASE		23

#define GDT_ENTRY_ESPFIX_SS		26
#define GDT_ENTRY_PERCPU		27
#define GDT_ENTRY_STACK_CANARY		28

#define GDT_ENTRY_DOUBLEFAULT_TSS	31

/*
 * Number of entries in the GDT table:
 */
#define GDT_ENTRIES			32

/*
 * Segment selector values corresponding to the above entries:
 */

#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)
#define __ESPFIX_SS			(GDT_ENTRY_ESPFIX_SS*8)

/* segment for calling fn: */
#define PNP_CS32			(GDT_ENTRY_PNPBIOS_CS32*8)
/* code segment for BIOS: */
#define PNP_CS16			(GDT_ENTRY_PNPBIOS_CS16*8)

/* "Is this PNP code selector (PNP_CS32 or PNP_CS16)?" */
#define SEGMENT_IS_PNP_CODE(x)		(((x) & 0xf4) == PNP_CS32)

/* data segment for BIOS: */
#define PNP_DS				(GDT_ENTRY_PNPBIOS_DS*8)
/* transfer data segment: */
#define PNP_TS1				(GDT_ENTRY_PNPBIOS_TS1*8)
/* another data segment: */
#define PNP_TS2				(GDT_ENTRY_PNPBIOS_TS2*8)

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

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

#else /* 64-bit: */

#include <asm/cache.h>

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

/*
 * We cannot use the same code segment descriptor for user and kernel mode,
 * not even in long flat mode, because of different DPL.
 *
 * GDT layout to get 64-bit SYSCALL/SYSRET support right. SYSRET hardcodes
 * selectors:
 *
 *   if returning to 32-bit userspace: cs = STAR.SYSRET_CS,
 *   if returning to 64-bit userspace: cs = STAR.SYSRET_CS+16,
 *
 * ss = STAR.SYSRET_CS+8 (in either case)
 *
 * thus USER_DS should be between 32-bit and 64-bit code selectors:
 */
#define GDT_ENTRY_DEFAULT_USER32_CS	4
#define GDT_ENTRY_DEFAULT_USER_DS	5
#define GDT_ENTRY_DEFAULT_USER_CS	6

/* Needs two entries */
#define GDT_ENTRY_TSS			8
/* Needs two entries */
#define GDT_ENTRY_LDT			10

#define GDT_ENTRY_TLS_MIN		12
#define GDT_ENTRY_TLS_MAX		14

/* Abused to load per CPU data from limit */
#define GDT_ENTRY_PER_CPU		15

/*
 * Number of entries in the GDT table:
 */
#define GDT_ENTRIES			16

/*
 * Segment selector values corresponding to the above entries:
 *
 * Note, selectors also need to have a correct RPL,
 * expressed with the +3 value for user-space selectors:
 */
#define __KERNEL32_CS			(GDT_ENTRY_KERNEL32_CS*8)
#define __KERNEL_CS			(GDT_ENTRY_KERNEL_CS*8)
#define __KERNEL_DS			(GDT_ENTRY_KERNEL_DS*8)
#define __USER32_CS			(GDT_ENTRY_DEFAULT_USER32_CS*8 + 3)
#define __USER_DS			(GDT_ENTRY_DEFAULT_USER_DS*8 + 3)
#define __USER32_DS			__USER_DS
#define __USER_CS			(GDT_ENTRY_DEFAULT_USER_CS*8 + 3)
#define __PER_CPU_SEG			(GDT_ENTRY_PER_CPU*8 + 3)

#endif

#ifndef CONFIG_PARAVIRT
# define get_kernel_rpl()		0
#endif

#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__

/*
 * early_idt_handler_array is an array of entry points referenced in the
 * early IDT.  For simplicity, it's a real array with one entry point
 * every nine bytes.  That leaves room for an optional 'push $0' if the
 * vector has no error code (two bytes), a 'push $vector_number' (two
 * bytes), and a jump to the common entry code (up to five bytes).
 */
#define EARLY_IDT_HANDLER_SIZE 9

#ifndef __ASSEMBLY__

extern const char early_idt_handler_array[NUM_EXCEPTION_VECTORS][EARLY_IDT_HANDLER_SIZE];
#ifdef CONFIG_TRACING
# define trace_early_idt_handler_array early_idt_handler_array
#endif

/*
 * Load a segment. Fall back on loading the zero segment if something goes
 * wrong.  This variant assumes that loading zero fully clears the segment.
 * This is always the case on Intel CPUs and, even on 64-bit AMD CPUs, any
 * failure to fully clear the cached descriptor is only observable for
 * FS and GS.
 */
#define __loadsegment_simple(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)

#define __loadsegment_ss(value) __loadsegment_simple(ss, (value))
#define __loadsegment_ds(value) __loadsegment_simple(ds, (value))
#define __loadsegment_es(value) __loadsegment_simple(es, (value))

#ifdef CONFIG_X86_32

/*
 * On 32-bit systems, the hidden parts of FS and GS are unobservable if
 * the selector is NULL, so there's no funny business here.
 */
#define __loadsegment_fs(value) __loadsegment_simple(fs, (value))
#define __loadsegment_gs(value) __loadsegment_simple(gs, (value))

#else

static inline void __loadsegment_fs(unsigned short value)
{
	asm volatile("						\n"
		     "1:	movw %0, %%fs			\n"
		     "2:					\n"

		     _ASM_EXTABLE_HANDLE(1b, 2b, ex_handler_clear_fs)

		     : : "rm" (value) : "memory");
}

/* __loadsegment_gs is intentionally undefined.  Use load_gs_index instead. */

#endif

#define loadsegment(seg, value) __loadsegment_ ## seg (value)

/*
 * 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 */

#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	4	#include <linux/const.h>
45e876f7	5	#include <asm/alternative.h>
014eea51	6
72d64cc7 IM	7	/*
	8	* Constructor for a conventional segment GDT (or LDT) entry.
	9	* This is a macro so it can be used in initializers.
	10	*/
4fdf08b5	11	#define GDT_ENTRY(flags, base, limit) \
014eea51 PA	12	((((base) & _AC(0xff000000,ULL)) << (56-24)) \| \
	13	(((flags) & _AC(0x0000f0ff,ULL)) << 40) \| \
	14	(((limit) & _AC(0x000f0000,ULL)) << (48-16)) \| \
	15	(((base) & _AC(0x00ffffff,ULL)) << 16) \| \
	16	(((limit) & _AC(0x0000ffff,ULL))))
4fdf08b5	17
72d64cc7	18	/* Simple and small GDT entries for booting only: */
2a6648e6 PA	19
2a6648e6 PA	20	#define GDT_ENTRY_BOOT_CS 2
84f53788 DV	21	#define GDT_ENTRY_BOOT_DS 3
84f53788 DV	22	#define GDT_ENTRY_BOOT_TSS 4
72d64cc7 IM	23	#define __BOOT_CS (GDT_ENTRY_BOOT_CS*8)
	24	#define __BOOT_DS (GDT_ENTRY_BOOT_DS*8)
	25	#define __BOOT_TSS (GDT_ENTRY_BOOT_TSS*8)
	26
	27	/*
	28	* Bottom two bits of selector give the ring
	29	* privilege level
	30	*/
	31	#define SEGMENT_RPL_MASK 0x3
	32
	33	/* User mode is privilege level 3: */
	34	#define USER_RPL 0x3
	35
	36	/* Bit 2 is Table Indicator (TI): selects between LDT or GDT */
	37	#define SEGMENT_TI_MASK 0x4
	38	/* LDT segment has TI set ... */
	39	#define SEGMENT_LDT 0x4
	40	/* ... GDT has it cleared */
	41	#define SEGMENT_GDT 0x0
be9d1738	42
6b51311c BP	43	#define GDT_ENTRY_INVALID_SEG 0
6b51311c BP	44
96a388de	45	#ifdef CONFIG_X86_32
b23be399 GOC	46	/*
	47	* The layout of the per-CPU GDT under Linux:
	48	*
72d64cc7	49	* 0 - null <=== cacheline #1
b23be399 GOC	50	* 1 - reserved
	51	* 2 - reserved
	52	* 3 - reserved
	53	*
72d64cc7	54	* 4 - unused <=== cacheline #2
b23be399 GOC	55	* 5 - unused
	56	*
	57	* ------- start of TLS (Thread-Local Storage) segments:
	58	*
	59	* 6 - TLS segment #1 [ glibc's TLS segment ]
	60	* 7 - TLS segment #2 [ Wine's %fs Win32 segment ]
72d64cc7	61	* 8 - TLS segment #3 <=== cacheline #3
b23be399 GOC	62	* 9 - reserved
	63	* 10 - reserved
	64	* 11 - reserved
	65	*
	66	* ------- start of kernel segments:
	67	*
72d64cc7	68	* 12 - kernel code segment <=== cacheline #4
b23be399 GOC	69	* 13 - kernel data segment
	70	* 14 - default user CS
	71	* 15 - default user DS
72d64cc7	72	* 16 - TSS <=== cacheline #5
b23be399 GOC	73	* 17 - LDT
	74	* 18 - PNPBIOS support (16->32 gate)
	75	* 19 - PNPBIOS support
72d64cc7	76	* 20 - PNPBIOS support <=== cacheline #6
b23be399 GOC	77	* 21 - PNPBIOS support
	78	* 22 - PNPBIOS support
	79	* 23 - APM BIOS support
72d64cc7	80	* 24 - APM BIOS support <=== cacheline #7
b23be399 GOC	81	* 25 - APM BIOS support
	82	*
	83	* 26 - ESPFIX small SS
	84	* 27 - per-cpu [ offset to per-cpu data area ]
72d64cc7	85	* 28 - stack_canary-20 [ for stack protector ] <=== cacheline #8
b23be399 GOC	86	* 29 - unused
	87	* 30 - unused
	88	* 31 - TSS for double fault handler
	89	*/
72d64cc7 IM	90	#define GDT_ENTRY_TLS_MIN 6
72d64cc7 IM	91	#define GDT_ENTRY_TLS_MAX (GDT_ENTRY_TLS_MIN + GDT_ENTRY_TLS_ENTRIES - 1)
b23be399	92
84f53788 DV	93	#define GDT_ENTRY_KERNEL_CS 12
84f53788 DV	94	#define GDT_ENTRY_KERNEL_DS 13
b23be399	95	#define GDT_ENTRY_DEFAULT_USER_CS 14
b23be399	96	#define GDT_ENTRY_DEFAULT_USER_DS 15
84f53788 DV	97	#define GDT_ENTRY_TSS 16
	98	#define GDT_ENTRY_LDT 17
	99	#define GDT_ENTRY_PNPBIOS_CS32 18
	100	#define GDT_ENTRY_PNPBIOS_CS16 19
	101	#define GDT_ENTRY_PNPBIOS_DS 20
	102	#define GDT_ENTRY_PNPBIOS_TS1 21
	103	#define GDT_ENTRY_PNPBIOS_TS2 22
	104	#define GDT_ENTRY_APMBIOS_BASE 23
	105
	106	#define GDT_ENTRY_ESPFIX_SS 26
	107	#define GDT_ENTRY_PERCPU 27
	108	#define GDT_ENTRY_STACK_CANARY 28
b23be399	109
84f53788	110	#define GDT_ENTRY_DOUBLEFAULT_TSS 31
b23be399	111
72d64cc7 IM	112	/*
	113	* Number of entries in the GDT table:
	114	*/
	115	#define GDT_ENTRIES 32
	116
	117	/*
	118	* Segment selector values corresponding to the above entries:
	119	*/
	120
84f53788 DV	121	#define __KERNEL_CS (GDT_ENTRY_KERNEL_CS*8)
84f53788 DV	122	#define __KERNEL_DS (GDT_ENTRY_KERNEL_DS*8)
72d64cc7 IM	123	#define __USER_DS (GDT_ENTRY_DEFAULT_USER_DS*8 + 3)
72d64cc7 IM	124	#define __USER_CS (GDT_ENTRY_DEFAULT_USER_CS*8 + 3)
3234282f	125	#define __ESPFIX_SS (GDT_ENTRY_ESPFIX_SS*8)
72d64cc7 IM	126
	127	/* segment for calling fn: */
	128	#define PNP_CS32 (GDT_ENTRY_PNPBIOS_CS32*8)
	129	/* code segment for BIOS: */
	130	#define PNP_CS16 (GDT_ENTRY_PNPBIOS_CS16*8)
	131
84f53788	132	/* "Is this PNP code selector (PNP_CS32 or PNP_CS16)?" */
72d64cc7 IM	133	#define SEGMENT_IS_PNP_CODE(x) (((x) & 0xf4) == PNP_CS32)
	134
	135	/* data segment for BIOS: */
	136	#define PNP_DS (GDT_ENTRY_PNPBIOS_DS*8)
	137	/* transfer data segment: */
	138	#define PNP_TS1 (GDT_ENTRY_PNPBIOS_TS1*8)
	139	/* another data segment: */
	140	#define PNP_TS2 (GDT_ENTRY_PNPBIOS_TS2*8)
	141
b23be399	142	#ifdef CONFIG_SMP
72d64cc7	143	# define __KERNEL_PERCPU (GDT_ENTRY_PERCPU*8)
b23be399	144	#else
72d64cc7	145	# define __KERNEL_PERCPU 0
b23be399	146	#endif
72d64cc7	147
60a5317f	148	#ifdef CONFIG_CC_STACKPROTECTOR
72d64cc7	149	# define __KERNEL_STACK_CANARY (GDT_ENTRY_STACK_CANARY*8)
60a5317f	150	#else
72d64cc7	151	# define __KERNEL_STACK_CANARY 0
60a5317f TH	152	#endif
60a5317f TH	153
84f53788	154	#else /* 64-bit: */
b23be399	155
b23be399 GOC	156	#include <asm/cache.h>
b23be399 GOC	157
72d64cc7 IM	158	#define GDT_ENTRY_KERNEL32_CS 1
	159	#define GDT_ENTRY_KERNEL_CS 2
	160	#define GDT_ENTRY_KERNEL_DS 3
	161
b23be399	162	/*
72d64cc7 IM	163	* We cannot use the same code segment descriptor for user and kernel mode,
	164	* not even in long flat mode, because of different DPL.
	165	*
	166	* GDT layout to get 64-bit SYSCALL/SYSRET support right. SYSRET hardcodes
	167	* selectors:
	168	*
	169	* if returning to 32-bit userspace: cs = STAR.SYSRET_CS,
	170	* if returning to 64-bit userspace: cs = STAR.SYSRET_CS+16,
	171	*
84f53788	172	* ss = STAR.SYSRET_CS+8 (in either case)
72d64cc7	173	*
84f53788	174	* thus USER_DS should be between 32-bit and 64-bit code selectors:
b23be399	175	*/
72d64cc7 IM	176	#define GDT_ENTRY_DEFAULT_USER32_CS 4
	177	#define GDT_ENTRY_DEFAULT_USER_DS 5
	178	#define GDT_ENTRY_DEFAULT_USER_CS 6
	179
	180	/* Needs two entries */
	181	#define GDT_ENTRY_TSS 8
	182	/* Needs two entries */
	183	#define GDT_ENTRY_LDT 10
b23be399	184
72d64cc7 IM	185	#define GDT_ENTRY_TLS_MIN 12
72d64cc7 IM	186	#define GDT_ENTRY_TLS_MAX 14
b23be399	187
72d64cc7 IM	188	/* Abused to load per CPU data from limit */
72d64cc7 IM	189	#define GDT_ENTRY_PER_CPU 15
84f53788	190
72d64cc7 IM	191	/*
	192	* Number of entries in the GDT table:
	193	*/
	194	#define GDT_ENTRIES 16
b23be399	195
72d64cc7 IM	196	/*
	197	* Segment selector values corresponding to the above entries:
	198	*
	199	* Note, selectors also need to have a correct RPL,
	200	* expressed with the +3 value for user-space selectors:
	201	*/
	202	#define __KERNEL32_CS (GDT_ENTRY_KERNEL32_CS*8)
	203	#define __KERNEL_CS (GDT_ENTRY_KERNEL_CS*8)
	204	#define __KERNEL_DS (GDT_ENTRY_KERNEL_DS*8)
	205	#define __USER32_CS (GDT_ENTRY_DEFAULT_USER32_CS*8 + 3)
	206	#define __USER_DS (GDT_ENTRY_DEFAULT_USER_DS*8 + 3)
	207	#define __USER32_DS __USER_DS
	208	#define __USER_CS (GDT_ENTRY_DEFAULT_USER_CS*8 + 3)
	209	#define __PER_CPU_SEG (GDT_ENTRY_PER_CPU*8 + 3)
b23be399	210
96a388de	211	#endif
cef18950 GOC	212
cef18950 GOC	213	#ifndef CONFIG_PARAVIRT
72d64cc7	214	# define get_kernel_rpl() 0
cef18950 GOC	215	#endif
cef18950 GOC	216
72d64cc7 IM	217	#define IDT_ENTRIES 256
	218	#define NUM_EXCEPTION_VECTORS 32
	219
	220	/* Bitmask of exception vectors which push an error code on the stack: */
	221	#define EXCEPTION_ERRCODE_MASK 0x00027d00
	222
	223	#define GDT_SIZE (GDT_ENTRIES*8)
	224	#define GDT_ENTRY_TLS_ENTRIES 3
	225	#define TLS_SIZE (GDT_ENTRY_TLS_ENTRIES* 8)
15ee09b4	226
8866cd9d	227	#ifdef __KERNEL__
425be567 AL	228
	229	/*
	230	* early_idt_handler_array is an array of entry points referenced in the
	231	* early IDT. For simplicity, it's a real array with one entry point
	232	* every nine bytes. That leaves room for an optional 'push $0' if the
	233	* vector has no error code (two bytes), a 'push $vector_number' (two
	234	* bytes), and a jump to the common entry code (up to five bytes).
	235	*/
	236	#define EARLY_IDT_HANDLER_SIZE 9
	237
8866cd9d	238	#ifndef __ASSEMBLY__
72d64cc7	239
425be567	240	extern const char early_idt_handler_array[NUM_EXCEPTION_VECTORS][EARLY_IDT_HANDLER_SIZE];
25c74b10	241	#ifdef CONFIG_TRACING
425be567	242	# define trace_early_idt_handler_array early_idt_handler_array
25c74b10	243	#endif
f05e798a DH	244
f05e798a DH	245	/*
45e876f7 AL	246	* Load a segment. Fall back on loading the zero segment if something goes
	247	* wrong. This variant assumes that loading zero fully clears the segment.
	248	* This is always the case on Intel CPUs and, even on 64-bit AMD CPUs, any
	249	* failure to fully clear the cached descriptor is only observable for
	250	* FS and GS.
f05e798a	251	*/
45e876f7	252	#define __loadsegment_simple(seg, value) \
f05e798a DH	253	do { \
	254	unsigned short __val = (value); \
	255	\
	256	asm volatile(" \n" \
	257	"1: movl %k0,%%" #seg " \n" \
	258	\
	259	".section .fixup,\"ax\" \n" \
	260	"2: xorl %k0,%k0 \n" \
	261	" jmp 1b \n" \
	262	".previous \n" \
	263	\
	264	_ASM_EXTABLE(1b, 2b) \
	265	\
	266	: "+r" (__val) : : "memory"); \
	267	} while (0)
	268
45e876f7 AL	269	#define __loadsegment_ss(value) __loadsegment_simple(ss, (value))
	270	#define __loadsegment_ds(value) __loadsegment_simple(ds, (value))
	271	#define __loadsegment_es(value) __loadsegment_simple(es, (value))
	272
	273	#ifdef CONFIG_X86_32
	274
	275	/*
	276	* On 32-bit systems, the hidden parts of FS and GS are unobservable if
	277	* the selector is NULL, so there's no funny business here.
	278	*/
	279	#define __loadsegment_fs(value) __loadsegment_simple(fs, (value))
	280	#define __loadsegment_gs(value) __loadsegment_simple(gs, (value))
	281
	282	#else
	283
	284	static inline void __loadsegment_fs(unsigned short value)
	285	{
	286	asm volatile(" \n"
	287	"1: movw %0, %%fs \n"
	288	"2: \n"
	289
	290	_ASM_EXTABLE_HANDLE(1b, 2b, ex_handler_clear_fs)
	291
	292	: : "rm" (value) : "memory");
	293	}
	294
	295	/* __loadsegment_gs is intentionally undefined. Use load_gs_index instead. */
	296
	297	#endif
	298
	299	#define loadsegment(seg, value) __loadsegment_ ## seg (value)
	300
f05e798a	301	/*
72d64cc7	302	* Save a segment register away:
f05e798a DH	303	*/
	304	#define savesegment(seg, value) \
	305	asm("mov %%" #seg ",%0":"=r" (value) : : "memory")
	306
	307	/*
72d64cc7	308	* x86-32 user GS accessors:
f05e798a DH	309	*/
f05e798a DH	310	#ifdef CONFIG_X86_32
72d64cc7 IM	311	# ifdef CONFIG_X86_32_LAZY_GS
	312	# define get_user_gs(regs) (u16)({ unsigned long v; savesegment(gs, v); v; })
	313	# define set_user_gs(regs, v) loadsegment(gs, (unsigned long)(v))
	314	# define task_user_gs(tsk) ((tsk)->thread.gs)
	315	# define lazy_save_gs(v) savesegment(gs, (v))
	316	# define lazy_load_gs(v) loadsegment(gs, (v))
	317	# else /* X86_32_LAZY_GS */
	318	# define get_user_gs(regs) (u16)((regs)->gs)
	319	# define set_user_gs(regs, v) do { (regs)->gs = (v); } while (0)
	320	# define task_user_gs(tsk) (task_pt_regs(tsk)->gs)
	321	# define lazy_save_gs(v) do { } while (0)
	322	# define lazy_load_gs(v) do { } while (0)
	323	# endif /* X86_32_LAZY_GS */
f05e798a DH	324	#endif /* X86_32 */
f05e798a DH	325
f05e798a DH	326	#endif /* !__ASSEMBLY__ */
f05e798a DH	327	#endif /* __KERNEL__ */
8866cd9d	328
1965aae3	329	#endif /* _ASM_X86_SEGMENT_H */