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b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
1965aae3 PA |
2 | #ifndef _ASM_X86_SEGMENT_H |
3 | #define _ASM_X86_SEGMENT_H | |
cef18950 | 4 | |
014eea51 | 5 | #include <linux/const.h> |
45e876f7 | 6 | #include <asm/alternative.h> |
014eea51 | 7 | |
72d64cc7 IM |
8 | /* |
9 | * Constructor for a conventional segment GDT (or LDT) entry. | |
10 | * This is a macro so it can be used in initializers. | |
11 | */ | |
4fdf08b5 | 12 | #define GDT_ENTRY(flags, base, limit) \ |
014eea51 PA |
13 | ((((base) & _AC(0xff000000,ULL)) << (56-24)) | \ |
14 | (((flags) & _AC(0x0000f0ff,ULL)) << 40) | \ | |
15 | (((limit) & _AC(0x000f0000,ULL)) << (48-16)) | \ | |
16 | (((base) & _AC(0x00ffffff,ULL)) << 16) | \ | |
17 | (((limit) & _AC(0x0000ffff,ULL)))) | |
4fdf08b5 | 18 | |
72d64cc7 | 19 | /* Simple and small GDT entries for booting only: */ |
2a6648e6 PA |
20 | |
21 | #define GDT_ENTRY_BOOT_CS 2 | |
84f53788 DV |
22 | #define GDT_ENTRY_BOOT_DS 3 |
23 | #define GDT_ENTRY_BOOT_TSS 4 | |
72d64cc7 IM |
24 | #define __BOOT_CS (GDT_ENTRY_BOOT_CS*8) |
25 | #define __BOOT_DS (GDT_ENTRY_BOOT_DS*8) | |
26 | #define __BOOT_TSS (GDT_ENTRY_BOOT_TSS*8) | |
27 | ||
28 | /* | |
29 | * Bottom two bits of selector give the ring | |
30 | * privilege level | |
31 | */ | |
32 | #define SEGMENT_RPL_MASK 0x3 | |
33 | ||
34 | /* User mode is privilege level 3: */ | |
35 | #define USER_RPL 0x3 | |
36 | ||
37 | /* Bit 2 is Table Indicator (TI): selects between LDT or GDT */ | |
38 | #define SEGMENT_TI_MASK 0x4 | |
39 | /* LDT segment has TI set ... */ | |
40 | #define SEGMENT_LDT 0x4 | |
41 | /* ... GDT has it cleared */ | |
42 | #define SEGMENT_GDT 0x0 | |
be9d1738 | 43 | |
6b51311c BP |
44 | #define GDT_ENTRY_INVALID_SEG 0 |
45 | ||
96a388de | 46 | #ifdef CONFIG_X86_32 |
b23be399 GOC |
47 | /* |
48 | * The layout of the per-CPU GDT under Linux: | |
49 | * | |
72d64cc7 | 50 | * 0 - null <=== cacheline #1 |
b23be399 GOC |
51 | * 1 - reserved |
52 | * 2 - reserved | |
53 | * 3 - reserved | |
54 | * | |
72d64cc7 | 55 | * 4 - unused <=== cacheline #2 |
b23be399 GOC |
56 | * 5 - unused |
57 | * | |
58 | * ------- start of TLS (Thread-Local Storage) segments: | |
59 | * | |
60 | * 6 - TLS segment #1 [ glibc's TLS segment ] | |
61 | * 7 - TLS segment #2 [ Wine's %fs Win32 segment ] | |
72d64cc7 | 62 | * 8 - TLS segment #3 <=== cacheline #3 |
b23be399 GOC |
63 | * 9 - reserved |
64 | * 10 - reserved | |
65 | * 11 - reserved | |
66 | * | |
67 | * ------- start of kernel segments: | |
68 | * | |
72d64cc7 | 69 | * 12 - kernel code segment <=== cacheline #4 |
b23be399 GOC |
70 | * 13 - kernel data segment |
71 | * 14 - default user CS | |
72 | * 15 - default user DS | |
72d64cc7 | 73 | * 16 - TSS <=== cacheline #5 |
b23be399 GOC |
74 | * 17 - LDT |
75 | * 18 - PNPBIOS support (16->32 gate) | |
76 | * 19 - PNPBIOS support | |
72d64cc7 | 77 | * 20 - PNPBIOS support <=== cacheline #6 |
b23be399 GOC |
78 | * 21 - PNPBIOS support |
79 | * 22 - PNPBIOS support | |
80 | * 23 - APM BIOS support | |
72d64cc7 | 81 | * 24 - APM BIOS support <=== cacheline #7 |
b23be399 GOC |
82 | * 25 - APM BIOS support |
83 | * | |
84 | * 26 - ESPFIX small SS | |
85 | * 27 - per-cpu [ offset to per-cpu data area ] | |
72d64cc7 | 86 | * 28 - stack_canary-20 [ for stack protector ] <=== cacheline #8 |
b23be399 GOC |
87 | * 29 - unused |
88 | * 30 - unused | |
89 | * 31 - TSS for double fault handler | |
90 | */ | |
72d64cc7 IM |
91 | #define GDT_ENTRY_TLS_MIN 6 |
92 | #define GDT_ENTRY_TLS_MAX (GDT_ENTRY_TLS_MIN + GDT_ENTRY_TLS_ENTRIES - 1) | |
b23be399 | 93 | |
84f53788 DV |
94 | #define GDT_ENTRY_KERNEL_CS 12 |
95 | #define GDT_ENTRY_KERNEL_DS 13 | |
b23be399 | 96 | #define GDT_ENTRY_DEFAULT_USER_CS 14 |
b23be399 | 97 | #define GDT_ENTRY_DEFAULT_USER_DS 15 |
84f53788 DV |
98 | #define GDT_ENTRY_TSS 16 |
99 | #define GDT_ENTRY_LDT 17 | |
100 | #define GDT_ENTRY_PNPBIOS_CS32 18 | |
101 | #define GDT_ENTRY_PNPBIOS_CS16 19 | |
102 | #define GDT_ENTRY_PNPBIOS_DS 20 | |
103 | #define GDT_ENTRY_PNPBIOS_TS1 21 | |
104 | #define GDT_ENTRY_PNPBIOS_TS2 22 | |
105 | #define GDT_ENTRY_APMBIOS_BASE 23 | |
106 | ||
107 | #define GDT_ENTRY_ESPFIX_SS 26 | |
108 | #define GDT_ENTRY_PERCPU 27 | |
109 | #define GDT_ENTRY_STACK_CANARY 28 | |
b23be399 | 110 | |
84f53788 | 111 | #define GDT_ENTRY_DOUBLEFAULT_TSS 31 |
b23be399 | 112 | |
72d64cc7 IM |
113 | /* |
114 | * Number of entries in the GDT table: | |
115 | */ | |
116 | #define GDT_ENTRIES 32 | |
117 | ||
118 | /* | |
119 | * Segment selector values corresponding to the above entries: | |
120 | */ | |
121 | ||
84f53788 DV |
122 | #define __KERNEL_CS (GDT_ENTRY_KERNEL_CS*8) |
123 | #define __KERNEL_DS (GDT_ENTRY_KERNEL_DS*8) | |
72d64cc7 IM |
124 | #define __USER_DS (GDT_ENTRY_DEFAULT_USER_DS*8 + 3) |
125 | #define __USER_CS (GDT_ENTRY_DEFAULT_USER_CS*8 + 3) | |
3234282f | 126 | #define __ESPFIX_SS (GDT_ENTRY_ESPFIX_SS*8) |
72d64cc7 IM |
127 | |
128 | /* segment for calling fn: */ | |
129 | #define PNP_CS32 (GDT_ENTRY_PNPBIOS_CS32*8) | |
130 | /* code segment for BIOS: */ | |
131 | #define PNP_CS16 (GDT_ENTRY_PNPBIOS_CS16*8) | |
132 | ||
84f53788 | 133 | /* "Is this PNP code selector (PNP_CS32 or PNP_CS16)?" */ |
72d64cc7 IM |
134 | #define SEGMENT_IS_PNP_CODE(x) (((x) & 0xf4) == PNP_CS32) |
135 | ||
136 | /* data segment for BIOS: */ | |
137 | #define PNP_DS (GDT_ENTRY_PNPBIOS_DS*8) | |
138 | /* transfer data segment: */ | |
139 | #define PNP_TS1 (GDT_ENTRY_PNPBIOS_TS1*8) | |
140 | /* another data segment: */ | |
141 | #define PNP_TS2 (GDT_ENTRY_PNPBIOS_TS2*8) | |
142 | ||
b23be399 | 143 | #ifdef CONFIG_SMP |
72d64cc7 | 144 | # define __KERNEL_PERCPU (GDT_ENTRY_PERCPU*8) |
b23be399 | 145 | #else |
72d64cc7 | 146 | # define __KERNEL_PERCPU 0 |
b23be399 | 147 | #endif |
72d64cc7 | 148 | |
60a5317f | 149 | #ifdef CONFIG_CC_STACKPROTECTOR |
72d64cc7 | 150 | # define __KERNEL_STACK_CANARY (GDT_ENTRY_STACK_CANARY*8) |
60a5317f | 151 | #else |
72d64cc7 | 152 | # define __KERNEL_STACK_CANARY 0 |
60a5317f TH |
153 | #endif |
154 | ||
84f53788 | 155 | #else /* 64-bit: */ |
b23be399 | 156 | |
b23be399 GOC |
157 | #include <asm/cache.h> |
158 | ||
72d64cc7 IM |
159 | #define GDT_ENTRY_KERNEL32_CS 1 |
160 | #define GDT_ENTRY_KERNEL_CS 2 | |
161 | #define GDT_ENTRY_KERNEL_DS 3 | |
162 | ||
b23be399 | 163 | /* |
72d64cc7 IM |
164 | * We cannot use the same code segment descriptor for user and kernel mode, |
165 | * not even in long flat mode, because of different DPL. | |
166 | * | |
167 | * GDT layout to get 64-bit SYSCALL/SYSRET support right. SYSRET hardcodes | |
168 | * selectors: | |
169 | * | |
170 | * if returning to 32-bit userspace: cs = STAR.SYSRET_CS, | |
171 | * if returning to 64-bit userspace: cs = STAR.SYSRET_CS+16, | |
172 | * | |
84f53788 | 173 | * ss = STAR.SYSRET_CS+8 (in either case) |
72d64cc7 | 174 | * |
84f53788 | 175 | * thus USER_DS should be between 32-bit and 64-bit code selectors: |
b23be399 | 176 | */ |
72d64cc7 IM |
177 | #define GDT_ENTRY_DEFAULT_USER32_CS 4 |
178 | #define GDT_ENTRY_DEFAULT_USER_DS 5 | |
179 | #define GDT_ENTRY_DEFAULT_USER_CS 6 | |
180 | ||
181 | /* Needs two entries */ | |
182 | #define GDT_ENTRY_TSS 8 | |
183 | /* Needs two entries */ | |
184 | #define GDT_ENTRY_LDT 10 | |
b23be399 | 185 | |
72d64cc7 IM |
186 | #define GDT_ENTRY_TLS_MIN 12 |
187 | #define GDT_ENTRY_TLS_MAX 14 | |
b23be399 | 188 | |
72d64cc7 IM |
189 | /* Abused to load per CPU data from limit */ |
190 | #define GDT_ENTRY_PER_CPU 15 | |
84f53788 | 191 | |
72d64cc7 IM |
192 | /* |
193 | * Number of entries in the GDT table: | |
194 | */ | |
195 | #define GDT_ENTRIES 16 | |
b23be399 | 196 | |
72d64cc7 IM |
197 | /* |
198 | * Segment selector values corresponding to the above entries: | |
199 | * | |
200 | * Note, selectors also need to have a correct RPL, | |
201 | * expressed with the +3 value for user-space selectors: | |
202 | */ | |
203 | #define __KERNEL32_CS (GDT_ENTRY_KERNEL32_CS*8) | |
204 | #define __KERNEL_CS (GDT_ENTRY_KERNEL_CS*8) | |
205 | #define __KERNEL_DS (GDT_ENTRY_KERNEL_DS*8) | |
206 | #define __USER32_CS (GDT_ENTRY_DEFAULT_USER32_CS*8 + 3) | |
207 | #define __USER_DS (GDT_ENTRY_DEFAULT_USER_DS*8 + 3) | |
208 | #define __USER32_DS __USER_DS | |
209 | #define __USER_CS (GDT_ENTRY_DEFAULT_USER_CS*8 + 3) | |
210 | #define __PER_CPU_SEG (GDT_ENTRY_PER_CPU*8 + 3) | |
b23be399 | 211 | |
96a388de | 212 | #endif |
cef18950 GOC |
213 | |
214 | #ifndef CONFIG_PARAVIRT | |
72d64cc7 | 215 | # define get_kernel_rpl() 0 |
cef18950 GOC |
216 | #endif |
217 | ||
72d64cc7 IM |
218 | #define IDT_ENTRIES 256 |
219 | #define NUM_EXCEPTION_VECTORS 32 | |
220 | ||
221 | /* Bitmask of exception vectors which push an error code on the stack: */ | |
222 | #define EXCEPTION_ERRCODE_MASK 0x00027d00 | |
223 | ||
224 | #define GDT_SIZE (GDT_ENTRIES*8) | |
225 | #define GDT_ENTRY_TLS_ENTRIES 3 | |
226 | #define TLS_SIZE (GDT_ENTRY_TLS_ENTRIES* 8) | |
15ee09b4 | 227 | |
8866cd9d | 228 | #ifdef __KERNEL__ |
425be567 AL |
229 | |
230 | /* | |
231 | * early_idt_handler_array is an array of entry points referenced in the | |
232 | * early IDT. For simplicity, it's a real array with one entry point | |
233 | * every nine bytes. That leaves room for an optional 'push $0' if the | |
234 | * vector has no error code (two bytes), a 'push $vector_number' (two | |
235 | * bytes), and a jump to the common entry code (up to five bytes). | |
236 | */ | |
237 | #define EARLY_IDT_HANDLER_SIZE 9 | |
238 | ||
8866cd9d | 239 | #ifndef __ASSEMBLY__ |
72d64cc7 | 240 | |
425be567 | 241 | extern const char early_idt_handler_array[NUM_EXCEPTION_VECTORS][EARLY_IDT_HANDLER_SIZE]; |
87e81786 | 242 | extern void early_ignore_irq(void); |
f05e798a DH |
243 | |
244 | /* | |
45e876f7 AL |
245 | * Load a segment. Fall back on loading the zero segment if something goes |
246 | * wrong. This variant assumes that loading zero fully clears the segment. | |
247 | * This is always the case on Intel CPUs and, even on 64-bit AMD CPUs, any | |
248 | * failure to fully clear the cached descriptor is only observable for | |
249 | * FS and GS. | |
f05e798a | 250 | */ |
45e876f7 | 251 | #define __loadsegment_simple(seg, value) \ |
f05e798a DH |
252 | do { \ |
253 | unsigned short __val = (value); \ | |
254 | \ | |
255 | asm volatile(" \n" \ | |
256 | "1: movl %k0,%%" #seg " \n" \ | |
257 | \ | |
258 | ".section .fixup,\"ax\" \n" \ | |
259 | "2: xorl %k0,%k0 \n" \ | |
260 | " jmp 1b \n" \ | |
261 | ".previous \n" \ | |
262 | \ | |
263 | _ASM_EXTABLE(1b, 2b) \ | |
264 | \ | |
265 | : "+r" (__val) : : "memory"); \ | |
266 | } while (0) | |
267 | ||
45e876f7 AL |
268 | #define __loadsegment_ss(value) __loadsegment_simple(ss, (value)) |
269 | #define __loadsegment_ds(value) __loadsegment_simple(ds, (value)) | |
270 | #define __loadsegment_es(value) __loadsegment_simple(es, (value)) | |
271 | ||
272 | #ifdef CONFIG_X86_32 | |
273 | ||
274 | /* | |
275 | * On 32-bit systems, the hidden parts of FS and GS are unobservable if | |
276 | * the selector is NULL, so there's no funny business here. | |
277 | */ | |
278 | #define __loadsegment_fs(value) __loadsegment_simple(fs, (value)) | |
279 | #define __loadsegment_gs(value) __loadsegment_simple(gs, (value)) | |
280 | ||
281 | #else | |
282 | ||
283 | static inline void __loadsegment_fs(unsigned short value) | |
284 | { | |
285 | asm volatile(" \n" | |
286 | "1: movw %0, %%fs \n" | |
287 | "2: \n" | |
288 | ||
289 | _ASM_EXTABLE_HANDLE(1b, 2b, ex_handler_clear_fs) | |
290 | ||
291 | : : "rm" (value) : "memory"); | |
292 | } | |
293 | ||
294 | /* __loadsegment_gs is intentionally undefined. Use load_gs_index instead. */ | |
295 | ||
296 | #endif | |
297 | ||
298 | #define loadsegment(seg, value) __loadsegment_ ## seg (value) | |
299 | ||
f05e798a | 300 | /* |
72d64cc7 | 301 | * Save a segment register away: |
f05e798a DH |
302 | */ |
303 | #define savesegment(seg, value) \ | |
304 | asm("mov %%" #seg ",%0":"=r" (value) : : "memory") | |
305 | ||
306 | /* | |
72d64cc7 | 307 | * x86-32 user GS accessors: |
f05e798a DH |
308 | */ |
309 | #ifdef CONFIG_X86_32 | |
72d64cc7 IM |
310 | # ifdef CONFIG_X86_32_LAZY_GS |
311 | # define get_user_gs(regs) (u16)({ unsigned long v; savesegment(gs, v); v; }) | |
312 | # define set_user_gs(regs, v) loadsegment(gs, (unsigned long)(v)) | |
313 | # define task_user_gs(tsk) ((tsk)->thread.gs) | |
314 | # define lazy_save_gs(v) savesegment(gs, (v)) | |
315 | # define lazy_load_gs(v) loadsegment(gs, (v)) | |
316 | # else /* X86_32_LAZY_GS */ | |
317 | # define get_user_gs(regs) (u16)((regs)->gs) | |
318 | # define set_user_gs(regs, v) do { (regs)->gs = (v); } while (0) | |
319 | # define task_user_gs(tsk) (task_pt_regs(tsk)->gs) | |
320 | # define lazy_save_gs(v) do { } while (0) | |
321 | # define lazy_load_gs(v) do { } while (0) | |
322 | # endif /* X86_32_LAZY_GS */ | |
f05e798a DH |
323 | #endif /* X86_32 */ |
324 | ||
f05e798a DH |
325 | #endif /* !__ASSEMBLY__ */ |
326 | #endif /* __KERNEL__ */ | |
8866cd9d | 327 | |
1965aae3 | 328 | #endif /* _ASM_X86_SEGMENT_H */ |