1 #ifndef _ASM_X86_SEGMENT_H 2 #define _ASM_X86_SEGMENT_H 3 4 #include <linux/const.h> 5 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) \ 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)))) 14 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 23 #define GDT_ENTRY_BOOT_TSS (GDT_ENTRY_BOOT_CS + 2) 24 #define __BOOT_TSS (GDT_ENTRY_BOOT_TSS * 8) 25 26 #ifdef CONFIG_X86_32 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 ] 66 * 28 - stack_canary-20 [ for stack protector ] 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 75 76 #define GDT_ENTRY_DEFAULT_USER_DS 15 77 78 #define GDT_ENTRY_KERNEL_BASE (12) 79 80 #define GDT_ENTRY_KERNEL_CS (GDT_ENTRY_KERNEL_BASE+0) 81 82 #define GDT_ENTRY_KERNEL_DS (GDT_ENTRY_KERNEL_BASE+1) 83 84 #define GDT_ENTRY_TSS (GDT_ENTRY_KERNEL_BASE+4) 85 #define GDT_ENTRY_LDT (GDT_ENTRY_KERNEL_BASE+5) 86 87 #define GDT_ENTRY_PNPBIOS_BASE (GDT_ENTRY_KERNEL_BASE+6) 88 #define GDT_ENTRY_APMBIOS_BASE (GDT_ENTRY_KERNEL_BASE+11) 89 90 #define GDT_ENTRY_ESPFIX_SS (GDT_ENTRY_KERNEL_BASE+14) 91 #define __ESPFIX_SS (GDT_ENTRY_ESPFIX_SS*8) 92 93 #define GDT_ENTRY_PERCPU (GDT_ENTRY_KERNEL_BASE+15) 94 #ifdef CONFIG_SMP 95 #define __KERNEL_PERCPU (GDT_ENTRY_PERCPU * 8) 96 #else 97 #define __KERNEL_PERCPU 0 98 #endif 99 100 #define GDT_ENTRY_STACK_CANARY (GDT_ENTRY_KERNEL_BASE+16) 101 #ifdef CONFIG_CC_STACKPROTECTOR 102 #define __KERNEL_STACK_CANARY (GDT_ENTRY_STACK_CANARY*8) 103 #else 104 #define __KERNEL_STACK_CANARY 0 105 #endif 106 107 #define GDT_ENTRY_DOUBLEFAULT_TSS 31 108 109 /* 110 * The GDT has 32 entries 111 */ 112 #define GDT_ENTRIES 32 113 114 /* 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 */ 142 143 /* Matches PNP_CS32 and PNP_CS16 (they must be consecutive) */ 144 #define SEGMENT_IS_PNP_CODE(x) (((x) & 0xf4) == GDT_ENTRY_PNPBIOS_BASE * 8) 145 146 147 #else 148 #include <asm/cache.h> 149 150 #define GDT_ENTRY_KERNEL32_CS 1 151 #define GDT_ENTRY_KERNEL_CS 2 152 #define GDT_ENTRY_KERNEL_DS 3 153 154 #define __KERNEL32_CS (GDT_ENTRY_KERNEL32_CS * 8) 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 */ 162 #define GDT_ENTRY_DEFAULT_USER32_CS 4 163 #define GDT_ENTRY_DEFAULT_USER_DS 5 164 #define GDT_ENTRY_DEFAULT_USER_CS 6 165 #define __USER32_CS (GDT_ENTRY_DEFAULT_USER32_CS*8+3) 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 16 184 185 #endif 186 187 #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) 191 #ifndef CONFIG_PARAVIRT 192 #define get_kernel_rpl() 0 193 #endif 194 195 /* 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 256 207 #define NUM_EXCEPTION_VECTORS 32 208 /* Bitmask of exception vectors which push an error code on the stack */ 209 #define EXCEPTION_ERRCODE_MASK 0x00027d00 210 #define GDT_SIZE (GDT_ENTRIES * 8) 211 #define GDT_ENTRY_TLS_ENTRIES 3 212 #define TLS_SIZE (GDT_ENTRY_TLS_ENTRIES * 8) 213 214 #ifdef __KERNEL__ 215 #ifndef __ASSEMBLY__ 216 extern const char early_idt_handlers[NUM_EXCEPTION_VECTORS][2+2+5]; 217 #ifdef CONFIG_TRACING 218 #define trace_early_idt_handlers early_idt_handlers 219 #endif 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__ */ 276 277 #endif /* _ASM_X86_SEGMENT_H */ 278