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 #define SEGMENT_RPL_MASK 0x3 /* 27 * Bottom two bits of selector give the ring 28 * privilege level 29 */ 30 #define SEGMENT_TI_MASK 0x4 /* Bit 2 is table indicator (LDT/GDT) */ 31 #define USER_RPL 0x3 /* User mode is privilege level 3 */ 32 #define SEGMENT_LDT 0x4 /* LDT segment has TI set... */ 33 #define SEGMENT_GDT 0x0 /* ... GDT has it cleared */ 34 35 #ifdef CONFIG_X86_32 36 /* 37 * The layout of the per-CPU GDT under Linux: 38 * 39 * 0 - null 40 * 1 - reserved 41 * 2 - reserved 42 * 3 - reserved 43 * 44 * 4 - unused <==== new cacheline 45 * 5 - unused 46 * 47 * ------- start of TLS (Thread-Local Storage) segments: 48 * 49 * 6 - TLS segment #1 [ glibc's TLS segment ] 50 * 7 - TLS segment #2 [ Wine's %fs Win32 segment ] 51 * 8 - TLS segment #3 52 * 9 - reserved 53 * 10 - reserved 54 * 11 - reserved 55 * 56 * ------- start of kernel segments: 57 * 58 * 12 - kernel code segment <==== new cacheline 59 * 13 - kernel data segment 60 * 14 - default user CS 61 * 15 - default user DS 62 * 16 - TSS 63 * 17 - LDT 64 * 18 - PNPBIOS support (16->32 gate) 65 * 19 - PNPBIOS support 66 * 20 - PNPBIOS support 67 * 21 - PNPBIOS support 68 * 22 - PNPBIOS support 69 * 23 - APM BIOS support 70 * 24 - APM BIOS support 71 * 25 - APM BIOS support 72 * 73 * 26 - ESPFIX small SS 74 * 27 - per-cpu [ offset to per-cpu data area ] 75 * 28 - stack_canary-20 [ for stack protector ] 76 * 29 - unused 77 * 30 - unused 78 * 31 - TSS for double fault handler 79 */ 80 #define GDT_ENTRY_TLS_MIN 6 81 #define GDT_ENTRY_TLS_MAX (GDT_ENTRY_TLS_MIN + GDT_ENTRY_TLS_ENTRIES - 1) 82 83 #define GDT_ENTRY_DEFAULT_USER_CS 14 84 85 #define GDT_ENTRY_DEFAULT_USER_DS 15 86 87 #define GDT_ENTRY_KERNEL_BASE (12) 88 89 #define GDT_ENTRY_KERNEL_CS (GDT_ENTRY_KERNEL_BASE+0) 90 91 #define GDT_ENTRY_KERNEL_DS (GDT_ENTRY_KERNEL_BASE+1) 92 93 #define GDT_ENTRY_TSS (GDT_ENTRY_KERNEL_BASE+4) 94 #define GDT_ENTRY_LDT (GDT_ENTRY_KERNEL_BASE+5) 95 96 #define GDT_ENTRY_PNPBIOS_BASE (GDT_ENTRY_KERNEL_BASE+6) 97 #define GDT_ENTRY_APMBIOS_BASE (GDT_ENTRY_KERNEL_BASE+11) 98 99 #define GDT_ENTRY_ESPFIX_SS (GDT_ENTRY_KERNEL_BASE+14) 100 #define __ESPFIX_SS (GDT_ENTRY_ESPFIX_SS*8) 101 102 #define GDT_ENTRY_PERCPU (GDT_ENTRY_KERNEL_BASE+15) 103 #ifdef CONFIG_SMP 104 #define __KERNEL_PERCPU (GDT_ENTRY_PERCPU * 8) 105 #else 106 #define __KERNEL_PERCPU 0 107 #endif 108 109 #define GDT_ENTRY_STACK_CANARY (GDT_ENTRY_KERNEL_BASE+16) 110 #ifdef CONFIG_CC_STACKPROTECTOR 111 #define __KERNEL_STACK_CANARY (GDT_ENTRY_STACK_CANARY*8) 112 #else 113 #define __KERNEL_STACK_CANARY 0 114 #endif 115 116 #define GDT_ENTRY_DOUBLEFAULT_TSS 31 117 118 /* 119 * The GDT has 32 entries 120 */ 121 #define GDT_ENTRIES 32 122 123 /* The PnP BIOS entries in the GDT */ 124 #define GDT_ENTRY_PNPBIOS_CS32 (GDT_ENTRY_PNPBIOS_BASE + 0) 125 #define GDT_ENTRY_PNPBIOS_CS16 (GDT_ENTRY_PNPBIOS_BASE + 1) 126 #define GDT_ENTRY_PNPBIOS_DS (GDT_ENTRY_PNPBIOS_BASE + 2) 127 #define GDT_ENTRY_PNPBIOS_TS1 (GDT_ENTRY_PNPBIOS_BASE + 3) 128 #define GDT_ENTRY_PNPBIOS_TS2 (GDT_ENTRY_PNPBIOS_BASE + 4) 129 130 /* The PnP BIOS selectors */ 131 #define PNP_CS32 (GDT_ENTRY_PNPBIOS_CS32 * 8) /* segment for calling fn */ 132 #define PNP_CS16 (GDT_ENTRY_PNPBIOS_CS16 * 8) /* code segment for BIOS */ 133 #define PNP_DS (GDT_ENTRY_PNPBIOS_DS * 8) /* data segment for BIOS */ 134 #define PNP_TS1 (GDT_ENTRY_PNPBIOS_TS1 * 8) /* transfer data segment */ 135 #define PNP_TS2 (GDT_ENTRY_PNPBIOS_TS2 * 8) /* another data segment */ 136 137 138 /* 139 * Matching rules for certain types of segments. 140 */ 141 142 /* Matches PNP_CS32 and PNP_CS16 (they must be consecutive) */ 143 #define SEGMENT_IS_PNP_CODE(x) (((x) & 0xf4) == GDT_ENTRY_PNPBIOS_BASE * 8) 144 145 146 #else 147 #include <asm/cache.h> 148 149 #define GDT_ENTRY_KERNEL32_CS 1 150 #define GDT_ENTRY_KERNEL_CS 2 151 #define GDT_ENTRY_KERNEL_DS 3 152 153 #define __KERNEL32_CS (GDT_ENTRY_KERNEL32_CS * 8) 154 155 /* 156 * we cannot use the same code segment descriptor for user and kernel 157 * -- not even in the long flat mode, because of different DPL /kkeil 158 * The segment offset needs to contain a RPL. Grr. -AK 159 * GDT layout to get 64bit syscall right (sysret hardcodes gdt offsets) 160 */ 161 #define GDT_ENTRY_DEFAULT_USER32_CS 4 162 #define GDT_ENTRY_DEFAULT_USER_DS 5 163 #define GDT_ENTRY_DEFAULT_USER_CS 6 164 #define __USER32_CS (GDT_ENTRY_DEFAULT_USER32_CS*8+3) 165 #define __USER32_DS __USER_DS 166 167 #define GDT_ENTRY_TSS 8 /* needs two entries */ 168 #define GDT_ENTRY_LDT 10 /* needs two entries */ 169 #define GDT_ENTRY_TLS_MIN 12 170 #define GDT_ENTRY_TLS_MAX 14 171 172 #define GDT_ENTRY_PER_CPU 15 /* Abused to load per CPU data from limit */ 173 #define __PER_CPU_SEG (GDT_ENTRY_PER_CPU * 8 + 3) 174 175 /* TLS indexes for 64bit - hardcoded in arch_prctl */ 176 #define FS_TLS 0 177 #define GS_TLS 1 178 179 #define GS_TLS_SEL ((GDT_ENTRY_TLS_MIN+GS_TLS)*8 + 3) 180 #define FS_TLS_SEL ((GDT_ENTRY_TLS_MIN+FS_TLS)*8 + 3) 181 182 #define GDT_ENTRIES 16 183 184 #endif 185 186 #define __KERNEL_CS (GDT_ENTRY_KERNEL_CS*8) 187 #define __KERNEL_DS (GDT_ENTRY_KERNEL_DS*8) 188 #define __USER_DS (GDT_ENTRY_DEFAULT_USER_DS*8+3) 189 #define __USER_CS (GDT_ENTRY_DEFAULT_USER_CS*8+3) 190 #ifndef CONFIG_PARAVIRT 191 #define get_kernel_rpl() 0 192 #endif 193 194 #define IDT_ENTRIES 256 195 #define NUM_EXCEPTION_VECTORS 32 196 /* Bitmask of exception vectors which push an error code on the stack */ 197 #define EXCEPTION_ERRCODE_MASK 0x00027d00 198 #define GDT_SIZE (GDT_ENTRIES * 8) 199 #define GDT_ENTRY_TLS_ENTRIES 3 200 #define TLS_SIZE (GDT_ENTRY_TLS_ENTRIES * 8) 201 202 #ifdef __KERNEL__ 203 #ifndef __ASSEMBLY__ 204 extern const char early_idt_handlers[NUM_EXCEPTION_VECTORS][2+2+5]; 205 #ifdef CONFIG_TRACING 206 #define trace_early_idt_handlers early_idt_handlers 207 #endif 208 209 /* 210 * Load a segment. Fall back on loading the zero 211 * segment if something goes wrong.. 212 */ 213 #define loadsegment(seg, value) \ 214 do { \ 215 unsigned short __val = (value); \ 216 \ 217 asm volatile(" \n" \ 218 "1: movl %k0,%%" #seg " \n" \ 219 \ 220 ".section .fixup,\"ax\" \n" \ 221 "2: xorl %k0,%k0 \n" \ 222 " jmp 1b \n" \ 223 ".previous \n" \ 224 \ 225 _ASM_EXTABLE(1b, 2b) \ 226 \ 227 : "+r" (__val) : : "memory"); \ 228 } while (0) 229 230 /* 231 * Save a segment register away 232 */ 233 #define savesegment(seg, value) \ 234 asm("mov %%" #seg ",%0":"=r" (value) : : "memory") 235 236 /* 237 * x86_32 user gs accessors. 238 */ 239 #ifdef CONFIG_X86_32 240 #ifdef CONFIG_X86_32_LAZY_GS 241 #define get_user_gs(regs) (u16)({unsigned long v; savesegment(gs, v); v;}) 242 #define set_user_gs(regs, v) loadsegment(gs, (unsigned long)(v)) 243 #define task_user_gs(tsk) ((tsk)->thread.gs) 244 #define lazy_save_gs(v) savesegment(gs, (v)) 245 #define lazy_load_gs(v) loadsegment(gs, (v)) 246 #else /* X86_32_LAZY_GS */ 247 #define get_user_gs(regs) (u16)((regs)->gs) 248 #define set_user_gs(regs, v) do { (regs)->gs = (v); } while (0) 249 #define task_user_gs(tsk) (task_pt_regs(tsk)->gs) 250 #define lazy_save_gs(v) do { } while (0) 251 #define lazy_load_gs(v) do { } while (0) 252 #endif /* X86_32_LAZY_GS */ 253 #endif /* X86_32 */ 254 255 static inline unsigned long get_limit(unsigned long segment) 256 { 257 unsigned long __limit; 258 asm("lsll %1,%0" : "=r" (__limit) : "r" (segment)); 259 return __limit + 1; 260 } 261 262 #endif /* !__ASSEMBLY__ */ 263 #endif /* __KERNEL__ */ 264 265 #endif /* _ASM_X86_SEGMENT_H */ 266