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1965aae3 PA |
1 | #ifndef _ASM_X86_SEGMENT_H |
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 | |
20 | #define GDT_ENTRY_BOOT_CS 2 | |
84f53788 DV |
21 | #define GDT_ENTRY_BOOT_DS 3 |
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 |
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 |
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 |
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) |
122 | #define __KERNEL_DS (GDT_ENTRY_KERNEL_DS*8) | |
72d64cc7 IM |
123 | #define __USER_DS (GDT_ENTRY_DEFAULT_USER_DS*8 + 3) |
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 |
153 | ||
84f53788 | 154 | #else /* 64-bit: */ |
b23be399 | 155 | |
b23be399 GOC |
156 | #include <asm/cache.h> |
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 |
186 | #define GDT_ENTRY_TLS_MAX 14 | |
b23be399 | 187 | |
72d64cc7 IM |
188 | /* Abused to load per CPU data from limit */ |
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 | |
213 | #ifndef CONFIG_PARAVIRT | |
72d64cc7 | 214 | # define get_kernel_rpl() 0 |
cef18950 GOC |
215 | #endif |
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 | |
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 | */ |
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 */ |
325 | ||
f05e798a DH |
326 | #endif /* !__ASSEMBLY__ */ |
327 | #endif /* __KERNEL__ */ | |
8866cd9d | 328 | |
1965aae3 | 329 | #endif /* _ASM_X86_SEGMENT_H */ |