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H. Peter Anvin1965aae2008-10-22 22:26:29 -07001#ifndef _ASM_X86_SEGMENT_H
2#define _ASM_X86_SEGMENT_H
Glauber de Oliveira Costacef18952008-01-30 13:31:09 +01003
H. Peter Anvin014eea52011-02-14 18:33:55 -08004#include <linux/const.h>
5
Ingo Molnar72d64cc2015-03-24 20:45:42 +01006/*
7 * Constructor for a conventional segment GDT (or LDT) entry.
8 * This is a macro so it can be used in initializers.
9 */
H. Peter Anvin4fdf08b2008-07-17 11:29:24 -070010#define GDT_ENTRY(flags, base, limit) \
H. Peter Anvin014eea52011-02-14 18:33:55 -080011 ((((base) & _AC(0xff000000,ULL)) << (56-24)) | \
12 (((flags) & _AC(0x0000f0ff,ULL)) << 40) | \
13 (((limit) & _AC(0x000f0000,ULL)) << (48-16)) | \
14 (((base) & _AC(0x00ffffff,ULL)) << 16) | \
15 (((limit) & _AC(0x0000ffff,ULL))))
H. Peter Anvin4fdf08b2008-07-17 11:29:24 -070016
Ingo Molnar72d64cc2015-03-24 20:45:42 +010017/* Simple and small GDT entries for booting only: */
H. Peter Anvin2a6648e2008-01-30 13:33:01 +010018
19#define GDT_ENTRY_BOOT_CS 2
Denys Vlasenko84f53782015-03-22 22:01:12 +010020#define GDT_ENTRY_BOOT_DS 3
21#define GDT_ENTRY_BOOT_TSS 4
Ingo Molnar72d64cc2015-03-24 20:45:42 +010022#define __BOOT_CS (GDT_ENTRY_BOOT_CS*8)
23#define __BOOT_DS (GDT_ENTRY_BOOT_DS*8)
24#define __BOOT_TSS (GDT_ENTRY_BOOT_TSS*8)
H. Peter Anvin88089512008-01-30 13:33:02 +010025
Ingo Molnar72d64cc2015-03-24 20:45:42 +010026/*
27 * Bottom two bits of selector give the ring
28 * privilege level
29 */
30#define SEGMENT_RPL_MASK 0x3
31
32/* User mode is privilege level 3: */
33#define USER_RPL 0x3
34
35/* Bit 2 is Table Indicator (TI): selects between LDT or GDT */
36#define SEGMENT_TI_MASK 0x4
37/* LDT segment has TI set ... */
38#define SEGMENT_LDT 0x4
39/* ... GDT has it cleared */
40#define SEGMENT_GDT 0x0
Borislav Petkovbe9d1732014-12-09 13:25:59 +010041
Thomas Gleixner96a388d2007-10-11 11:20:03 +020042#ifdef CONFIG_X86_32
Glauber de Oliveira Costab23be392008-01-30 13:31:09 +010043/*
44 * The layout of the per-CPU GDT under Linux:
45 *
Ingo Molnar72d64cc2015-03-24 20:45:42 +010046 * 0 - null <=== cacheline #1
Glauber de Oliveira Costab23be392008-01-30 13:31:09 +010047 * 1 - reserved
48 * 2 - reserved
49 * 3 - reserved
50 *
Ingo Molnar72d64cc2015-03-24 20:45:42 +010051 * 4 - unused <=== cacheline #2
Glauber de Oliveira Costab23be392008-01-30 13:31:09 +010052 * 5 - unused
53 *
54 * ------- start of TLS (Thread-Local Storage) segments:
55 *
56 * 6 - TLS segment #1 [ glibc's TLS segment ]
57 * 7 - TLS segment #2 [ Wine's %fs Win32 segment ]
Ingo Molnar72d64cc2015-03-24 20:45:42 +010058 * 8 - TLS segment #3 <=== cacheline #3
Glauber de Oliveira Costab23be392008-01-30 13:31:09 +010059 * 9 - reserved
60 * 10 - reserved
61 * 11 - reserved
62 *
63 * ------- start of kernel segments:
64 *
Ingo Molnar72d64cc2015-03-24 20:45:42 +010065 * 12 - kernel code segment <=== cacheline #4
Glauber de Oliveira Costab23be392008-01-30 13:31:09 +010066 * 13 - kernel data segment
67 * 14 - default user CS
68 * 15 - default user DS
Ingo Molnar72d64cc2015-03-24 20:45:42 +010069 * 16 - TSS <=== cacheline #5
Glauber de Oliveira Costab23be392008-01-30 13:31:09 +010070 * 17 - LDT
71 * 18 - PNPBIOS support (16->32 gate)
72 * 19 - PNPBIOS support
Ingo Molnar72d64cc2015-03-24 20:45:42 +010073 * 20 - PNPBIOS support <=== cacheline #6
Glauber de Oliveira Costab23be392008-01-30 13:31:09 +010074 * 21 - PNPBIOS support
75 * 22 - PNPBIOS support
76 * 23 - APM BIOS support
Ingo Molnar72d64cc2015-03-24 20:45:42 +010077 * 24 - APM BIOS support <=== cacheline #7
Glauber de Oliveira Costab23be392008-01-30 13:31:09 +010078 * 25 - APM BIOS support
79 *
80 * 26 - ESPFIX small SS
81 * 27 - per-cpu [ offset to per-cpu data area ]
Ingo Molnar72d64cc2015-03-24 20:45:42 +010082 * 28 - stack_canary-20 [ for stack protector ] <=== cacheline #8
Glauber de Oliveira Costab23be392008-01-30 13:31:09 +010083 * 29 - unused
84 * 30 - unused
85 * 31 - TSS for double fault handler
86 */
Ingo Molnar72d64cc2015-03-24 20:45:42 +010087#define GDT_ENTRY_TLS_MIN 6
88#define GDT_ENTRY_TLS_MAX (GDT_ENTRY_TLS_MIN + GDT_ENTRY_TLS_ENTRIES - 1)
Glauber de Oliveira Costab23be392008-01-30 13:31:09 +010089
Denys Vlasenko84f53782015-03-22 22:01:12 +010090#define GDT_ENTRY_KERNEL_CS 12
91#define GDT_ENTRY_KERNEL_DS 13
Glauber de Oliveira Costab23be392008-01-30 13:31:09 +010092#define GDT_ENTRY_DEFAULT_USER_CS 14
Glauber de Oliveira Costab23be392008-01-30 13:31:09 +010093#define GDT_ENTRY_DEFAULT_USER_DS 15
Denys Vlasenko84f53782015-03-22 22:01:12 +010094#define GDT_ENTRY_TSS 16
95#define GDT_ENTRY_LDT 17
96#define GDT_ENTRY_PNPBIOS_CS32 18
97#define GDT_ENTRY_PNPBIOS_CS16 19
98#define GDT_ENTRY_PNPBIOS_DS 20
99#define GDT_ENTRY_PNPBIOS_TS1 21
100#define GDT_ENTRY_PNPBIOS_TS2 22
101#define GDT_ENTRY_APMBIOS_BASE 23
Glauber de Oliveira Costab23be392008-01-30 13:31:09 +0100102
Denys Vlasenko84f53782015-03-22 22:01:12 +0100103#define GDT_ENTRY_ESPFIX_SS 26
104#define GDT_ENTRY_PERCPU 27
105#define GDT_ENTRY_STACK_CANARY 28
Glauber de Oliveira Costab23be392008-01-30 13:31:09 +0100106
Denys Vlasenko84f53782015-03-22 22:01:12 +0100107#define GDT_ENTRY_DOUBLEFAULT_TSS 31
Glauber de Oliveira Costab23be392008-01-30 13:31:09 +0100108
Ingo Molnar72d64cc2015-03-24 20:45:42 +0100109/*
110 * Number of entries in the GDT table:
111 */
112#define GDT_ENTRIES 32
113
114/*
115 * Segment selector values corresponding to the above entries:
116 */
117
Denys Vlasenko84f53782015-03-22 22:01:12 +0100118#define __KERNEL_CS (GDT_ENTRY_KERNEL_CS*8)
119#define __KERNEL_DS (GDT_ENTRY_KERNEL_DS*8)
Ingo Molnar72d64cc2015-03-24 20:45:42 +0100120#define __USER_DS (GDT_ENTRY_DEFAULT_USER_DS*8 + 3)
121#define __USER_CS (GDT_ENTRY_DEFAULT_USER_CS*8 + 3)
Jan Beulich32342822010-10-19 14:52:26 +0100122#define __ESPFIX_SS (GDT_ENTRY_ESPFIX_SS*8)
Ingo Molnar72d64cc2015-03-24 20:45:42 +0100123
124/* segment for calling fn: */
125#define PNP_CS32 (GDT_ENTRY_PNPBIOS_CS32*8)
126/* code segment for BIOS: */
127#define PNP_CS16 (GDT_ENTRY_PNPBIOS_CS16*8)
128
Denys Vlasenko84f53782015-03-22 22:01:12 +0100129/* "Is this PNP code selector (PNP_CS32 or PNP_CS16)?" */
Ingo Molnar72d64cc2015-03-24 20:45:42 +0100130#define SEGMENT_IS_PNP_CODE(x) (((x) & 0xf4) == PNP_CS32)
131
132/* data segment for BIOS: */
133#define PNP_DS (GDT_ENTRY_PNPBIOS_DS*8)
134/* transfer data segment: */
135#define PNP_TS1 (GDT_ENTRY_PNPBIOS_TS1*8)
136/* another data segment: */
137#define PNP_TS2 (GDT_ENTRY_PNPBIOS_TS2*8)
138
Glauber de Oliveira Costab23be392008-01-30 13:31:09 +0100139#ifdef CONFIG_SMP
Ingo Molnar72d64cc2015-03-24 20:45:42 +0100140# define __KERNEL_PERCPU (GDT_ENTRY_PERCPU*8)
Thomas Gleixner96a388d2007-10-11 11:20:03 +0200141#else
Ingo Molnar72d64cc2015-03-24 20:45:42 +0100142# define __KERNEL_PERCPU 0
Tejun Heo60a53172009-02-09 22:17:40 +0900143#endif
144
Ingo Molnar72d64cc2015-03-24 20:45:42 +0100145#ifdef CONFIG_CC_STACKPROTECTOR
146# define __KERNEL_STACK_CANARY (GDT_ENTRY_STACK_CANARY*8)
147#else
148# define __KERNEL_STACK_CANARY 0
149#endif
Glauber de Oliveira Costab23be392008-01-30 13:31:09 +0100150
Denys Vlasenko84f53782015-03-22 22:01:12 +0100151#else /* 64-bit: */
Glauber de Oliveira Costab23be392008-01-30 13:31:09 +0100152
Glauber de Oliveira Costab23be392008-01-30 13:31:09 +0100153#include <asm/cache.h>
154
Ingo Molnar72d64cc2015-03-24 20:45:42 +0100155#define GDT_ENTRY_KERNEL32_CS 1
156#define GDT_ENTRY_KERNEL_CS 2
157#define GDT_ENTRY_KERNEL_DS 3
158
Glauber de Oliveira Costab23be392008-01-30 13:31:09 +0100159/*
Ingo Molnar72d64cc2015-03-24 20:45:42 +0100160 * We cannot use the same code segment descriptor for user and kernel mode,
161 * not even in long flat mode, because of different DPL.
162 *
163 * GDT layout to get 64-bit SYSCALL/SYSRET support right. SYSRET hardcodes
164 * selectors:
165 *
166 * if returning to 32-bit userspace: cs = STAR.SYSRET_CS,
167 * if returning to 64-bit userspace: cs = STAR.SYSRET_CS+16,
168 *
Denys Vlasenko84f53782015-03-22 22:01:12 +0100169 * ss = STAR.SYSRET_CS+8 (in either case)
Ingo Molnar72d64cc2015-03-24 20:45:42 +0100170 *
Denys Vlasenko84f53782015-03-22 22:01:12 +0100171 * thus USER_DS should be between 32-bit and 64-bit code selectors:
Glauber de Oliveira Costab23be392008-01-30 13:31:09 +0100172 */
Ingo Molnar72d64cc2015-03-24 20:45:42 +0100173#define GDT_ENTRY_DEFAULT_USER32_CS 4
174#define GDT_ENTRY_DEFAULT_USER_DS 5
175#define GDT_ENTRY_DEFAULT_USER_CS 6
Denys Vlasenko84f53782015-03-22 22:01:12 +0100176
Ingo Molnar72d64cc2015-03-24 20:45:42 +0100177/* Needs two entries */
178#define GDT_ENTRY_TSS 8
179/* Needs two entries */
180#define GDT_ENTRY_LDT 10
Denys Vlasenko84f53782015-03-22 22:01:12 +0100181
Ingo Molnar72d64cc2015-03-24 20:45:42 +0100182#define GDT_ENTRY_TLS_MIN 12
183#define GDT_ENTRY_TLS_MAX 14
Denys Vlasenko84f53782015-03-22 22:01:12 +0100184
Ingo Molnar72d64cc2015-03-24 20:45:42 +0100185/* Abused to load per CPU data from limit */
186#define GDT_ENTRY_PER_CPU 15
Glauber de Oliveira Costab23be392008-01-30 13:31:09 +0100187
Ingo Molnar72d64cc2015-03-24 20:45:42 +0100188/*
189 * Number of entries in the GDT table:
190 */
191#define GDT_ENTRIES 16
Glauber de Oliveira Costab23be392008-01-30 13:31:09 +0100192
Ingo Molnar72d64cc2015-03-24 20:45:42 +0100193/*
194 * Segment selector values corresponding to the above entries:
195 *
196 * Note, selectors also need to have a correct RPL,
197 * expressed with the +3 value for user-space selectors:
198 */
199#define __KERNEL32_CS (GDT_ENTRY_KERNEL32_CS*8)
200#define __KERNEL_CS (GDT_ENTRY_KERNEL_CS*8)
201#define __KERNEL_DS (GDT_ENTRY_KERNEL_DS*8)
202#define __USER32_CS (GDT_ENTRY_DEFAULT_USER32_CS*8 + 3)
203#define __USER_DS (GDT_ENTRY_DEFAULT_USER_DS*8 + 3)
204#define __USER32_DS __USER_DS
205#define __USER_CS (GDT_ENTRY_DEFAULT_USER_CS*8 + 3)
206#define __PER_CPU_SEG (GDT_ENTRY_PER_CPU*8 + 3)
Glauber de Oliveira Costab23be392008-01-30 13:31:09 +0100207
Ingo Molnar72d64cc2015-03-24 20:45:42 +0100208/* TLS indexes for 64-bit - hardcoded in arch_prctl(): */
209#define FS_TLS 0
210#define GS_TLS 1
211
212#define GS_TLS_SEL ((GDT_ENTRY_TLS_MIN+GS_TLS)*8 + 3)
213#define FS_TLS_SEL ((GDT_ENTRY_TLS_MIN+FS_TLS)*8 + 3)
Glauber de Oliveira Costab23be392008-01-30 13:31:09 +0100214
Thomas Gleixner96a388d2007-10-11 11:20:03 +0200215#endif
Glauber de Oliveira Costacef18952008-01-30 13:31:09 +0100216
217#ifndef CONFIG_PARAVIRT
Ingo Molnar72d64cc2015-03-24 20:45:42 +0100218# define get_kernel_rpl() 0
Glauber de Oliveira Costacef18952008-01-30 13:31:09 +0100219#endif
220
Ingo Molnar72d64cc2015-03-24 20:45:42 +0100221#define IDT_ENTRIES 256
222#define NUM_EXCEPTION_VECTORS 32
223
224/* Bitmask of exception vectors which push an error code on the stack: */
225#define EXCEPTION_ERRCODE_MASK 0x00027d00
226
227#define GDT_SIZE (GDT_ENTRIES*8)
228#define GDT_ENTRY_TLS_ENTRIES 3
229#define TLS_SIZE (GDT_ENTRY_TLS_ENTRIES* 8)
Glauber de Oliveira Costa15ee09b2008-01-30 13:31:09 +0100230
Roland McGrath8866cd92008-01-30 13:33:06 +0100231#ifdef __KERNEL__
232#ifndef __ASSEMBLY__
Ingo Molnar72d64cc2015-03-24 20:45:42 +0100233
H. Peter Anvin9900aa22012-04-18 17:16:49 -0700234extern const char early_idt_handlers[NUM_EXCEPTION_VECTORS][2+2+5];
Seiji Aguchi25c74b12013-10-30 16:37:00 -0400235#ifdef CONFIG_TRACING
Ingo Molnar72d64cc2015-03-24 20:45:42 +0100236# define trace_early_idt_handlers early_idt_handlers
Seiji Aguchi25c74b12013-10-30 16:37:00 -0400237#endif
David Howellsf05e7982012-03-28 18:11:12 +0100238
239/*
240 * Load a segment. Fall back on loading the zero
241 * segment if something goes wrong..
242 */
243#define loadsegment(seg, value) \
244do { \
245 unsigned short __val = (value); \
246 \
247 asm volatile(" \n" \
248 "1: movl %k0,%%" #seg " \n" \
249 \
250 ".section .fixup,\"ax\" \n" \
251 "2: xorl %k0,%k0 \n" \
252 " jmp 1b \n" \
253 ".previous \n" \
254 \
255 _ASM_EXTABLE(1b, 2b) \
256 \
257 : "+r" (__val) : : "memory"); \
258} while (0)
259
260/*
Ingo Molnar72d64cc2015-03-24 20:45:42 +0100261 * Save a segment register away:
David Howellsf05e7982012-03-28 18:11:12 +0100262 */
263#define savesegment(seg, value) \
264 asm("mov %%" #seg ",%0":"=r" (value) : : "memory")
265
266/*
Ingo Molnar72d64cc2015-03-24 20:45:42 +0100267 * x86-32 user GS accessors:
David Howellsf05e7982012-03-28 18:11:12 +0100268 */
269#ifdef CONFIG_X86_32
Ingo Molnar72d64cc2015-03-24 20:45:42 +0100270# ifdef CONFIG_X86_32_LAZY_GS
271# define get_user_gs(regs) (u16)({ unsigned long v; savesegment(gs, v); v; })
272# define set_user_gs(regs, v) loadsegment(gs, (unsigned long)(v))
273# define task_user_gs(tsk) ((tsk)->thread.gs)
274# define lazy_save_gs(v) savesegment(gs, (v))
275# define lazy_load_gs(v) loadsegment(gs, (v))
276# else /* X86_32_LAZY_GS */
277# define get_user_gs(regs) (u16)((regs)->gs)
278# define set_user_gs(regs, v) do { (regs)->gs = (v); } while (0)
279# define task_user_gs(tsk) (task_pt_regs(tsk)->gs)
280# define lazy_save_gs(v) do { } while (0)
281# define lazy_load_gs(v) do { } while (0)
282# endif /* X86_32_LAZY_GS */
David Howellsf05e7982012-03-28 18:11:12 +0100283#endif /* X86_32 */
284
David Howellsf05e7982012-03-28 18:11:12 +0100285#endif /* !__ASSEMBLY__ */
286#endif /* __KERNEL__ */
Roland McGrath8866cd92008-01-30 13:33:06 +0100287
H. Peter Anvin1965aae2008-10-22 22:26:29 -0700288#endif /* _ASM_X86_SEGMENT_H */