1 #ifndef _X86_DESC_H_ 2 #define _X86_DESC_H_ 3 4 /* 5 * selector 32-bit 64-bit 6 * 0x00 NULL descriptor NULL descriptor 7 * 0x08 ring-0 code segment (32-bit) ring-0 code segment (64-bit) 8 * 0x10 ring-0 data segment (32-bit) ring-0 data segment (32/64-bit) 9 * 0x18 ring-0 code segment (P=0) ring-0 code segment (64-bit, P=0) 10 * 0x20 intr_alt_stack TSS ring-0 code segment (32-bit) 11 * 0x28 ring-0 code segment (16-bit) same 12 * 0x30 ring-0 data segment (16-bit) same 13 * 0x38 (0x3b) ring-3 code segment (32-bit) same 14 * 0x40 (0x43) ring-3 data segment (32-bit) ring-3 data segment (32/64-bit) 15 * 0x48 (0x4b) **unused** ring-3 code segment (64-bit) 16 * 0x50-0x78 free to use for test cases same 17 * 0x80-0x870 primary TSS (CPU 0..254) same 18 * 0x878-0x1068 percpu area (CPU 0..254) not used 19 * 20 * Note that the same segment can be used for 32-bit and 64-bit data segments 21 * (the L bit is only defined for code segments) 22 * 23 * Selectors 0x08-0x10 and 0x3b-0x4b are set up for use with the SYSCALL 24 * and SYSRET instructions. 25 */ 26 27 #define KERNEL_CS 0x08 28 #define KERNEL_DS 0x10 29 #define NP_SEL 0x18 30 #ifdef __x86_64__ 31 #define KERNEL_CS32 0x20 32 #else 33 #define TSS_INTR 0x20 34 #endif 35 #define KERNEL_CS16 0x28 36 #define KERNEL_DS16 0x30 37 #define USER_CS32 0x3b 38 #define USER_DS 0x43 39 #ifdef __x86_64__ 40 #define USER_CS64 0x4b 41 #endif 42 43 /* Synonyms */ 44 #define KERNEL_DS32 KERNEL_DS 45 #define USER_DS32 USER_DS 46 47 #ifdef __x86_64__ 48 #define KERNEL_CS64 KERNEL_CS 49 #define USER_CS USER_CS64 50 #define KERNEL_DS64 KERNEL_DS 51 #define USER_DS64 USER_DS 52 #else 53 #define KERNEL_CS32 KERNEL_CS 54 #define USER_CS USER_CS32 55 #endif 56 57 #define FIRST_SPARE_SEL 0x50 58 #define TSS_MAIN 0x80 59 60 #ifdef __ASSEMBLY__ 61 #define __ASM_FORM(x, ...) x,## __VA_ARGS__ 62 #else 63 #define __ASM_FORM(x, ...) " " xstr(x,##__VA_ARGS__) " " 64 #endif 65 66 #ifndef __x86_64__ 67 #define __ASM_SEL(a,b) __ASM_FORM(a) 68 #else 69 #define __ASM_SEL(a,b) __ASM_FORM(b) 70 #endif 71 72 #include <setjmp.h> 73 74 void setup_idt(void); 75 void load_idt(void); 76 void setup_alt_stack(void); 77 78 struct ex_regs { 79 unsigned long rax, rcx, rdx, rbx; 80 unsigned long dummy, rbp, rsi, rdi; 81 #ifdef __x86_64__ 82 unsigned long r8, r9, r10, r11; 83 unsigned long r12, r13, r14, r15; 84 #endif 85 unsigned long vector; 86 unsigned long error_code; 87 unsigned long rip; 88 unsigned long cs; 89 unsigned long rflags; 90 #ifdef __x86_64__ 91 unsigned long rsp; 92 unsigned long ss; 93 #endif 94 }; 95 96 typedef void (*handler)(struct ex_regs *regs); 97 98 typedef struct { 99 u16 prev; 100 u16 res1; 101 u32 esp0; 102 u16 ss0; 103 u16 res2; 104 u32 esp1; 105 u16 ss1; 106 u16 res3; 107 u32 esp2; 108 u16 ss2; 109 u16 res4; 110 u32 cr3; 111 u32 eip; 112 u32 eflags; 113 u32 eax, ecx, edx, ebx, esp, ebp, esi, edi; 114 u16 es; 115 u16 res5; 116 u16 cs; 117 u16 res6; 118 u16 ss; 119 u16 res7; 120 u16 ds; 121 u16 res8; 122 u16 fs; 123 u16 res9; 124 u16 gs; 125 u16 res10; 126 u16 ldt; 127 u16 res11; 128 u16 t:1; 129 u16 res12:15; 130 u16 iomap_base; 131 } tss32_t; 132 133 typedef struct __attribute__((packed)) { 134 u32 res1; 135 u64 rsp0; 136 u64 rsp1; 137 u64 rsp2; 138 u64 res2; 139 u64 ist1; 140 u64 ist2; 141 u64 ist3; 142 u64 ist4; 143 u64 ist5; 144 u64 ist6; 145 u64 ist7; 146 u64 res3; 147 u16 res4; 148 u16 iomap_base; 149 } tss64_t; 150 151 #define __ASM_TRY(prefix, catch) \ 152 "movl $0, %%gs:4\n\t" \ 153 ".pushsection .data.ex\n\t" \ 154 __ASM_SEL(.long, .quad) " 1111f, " catch "\n\t" \ 155 ".popsection \n\t" \ 156 prefix "\n\t" \ 157 "1111:" 158 159 #define ASM_TRY(catch) __ASM_TRY("", catch) 160 161 /* Forced emulation prefix, used to invoke the emulator unconditionally. */ 162 #define KVM_FEP "ud2; .byte 'k', 'v', 'm';" 163 #define ASM_TRY_FEP(catch) __ASM_TRY(KVM_FEP, catch) 164 165 static inline bool is_fep_available(void) 166 { 167 /* 168 * Use the non-FEP ASM_TRY() as KVM will inject a #UD on the prefix 169 * itself if forced emulation is not available. 170 */ 171 asm goto(ASM_TRY("%l[fep_unavailable]") 172 KVM_FEP "nop\n\t" 173 ::: "memory" : fep_unavailable); 174 return true; 175 fep_unavailable: 176 return false; 177 } 178 179 typedef struct { 180 unsigned short offset0; 181 unsigned short selector; 182 unsigned short ist : 3; 183 unsigned short : 5; 184 unsigned short type : 4; 185 unsigned short : 1; 186 unsigned short dpl : 2; 187 unsigned short p : 1; 188 unsigned short offset1; 189 #ifdef __x86_64__ 190 unsigned offset2; 191 unsigned reserved; 192 #endif 193 } idt_entry_t; 194 195 typedef struct { 196 uint16_t limit1; 197 uint16_t base1; 198 uint8_t base2; 199 union { 200 uint16_t type_limit_flags; /* Type and limit flags */ 201 struct { 202 uint16_t type:4; 203 uint16_t s:1; 204 uint16_t dpl:2; 205 uint16_t p:1; 206 uint16_t limit2:4; 207 uint16_t avl:1; 208 uint16_t l:1; 209 uint16_t db:1; 210 uint16_t g:1; 211 } __attribute__((__packed__)); 212 } __attribute__((__packed__)); 213 uint8_t base3; 214 } __attribute__((__packed__)) gdt_entry_t; 215 216 #ifdef __x86_64__ 217 struct system_desc64 { 218 gdt_entry_t common; 219 uint32_t base4; 220 uint32_t zero; 221 } __attribute__((__packed__)); 222 #endif 223 224 #define DESC_BUSY 2 225 226 extern idt_entry_t boot_idt[256]; 227 228 #ifndef __x86_64__ 229 extern tss32_t tss[]; 230 extern tss32_t tss_intr; 231 void set_gdt_task_gate(u16 tss_sel, u16 sel); 232 void set_idt_task_gate(int vec, u16 sel); 233 void set_intr_task_gate(int vec, void *fn); 234 void setup_tss32(void); 235 #else 236 extern tss64_t tss[]; 237 #endif 238 extern gdt_entry_t gdt[]; 239 240 unsigned exception_vector(void); 241 unsigned exception_error_code(void); 242 bool exception_rflags_rf(void); 243 void set_desc_entry(idt_entry_t *e, size_t e_sz, void *addr, 244 u16 sel, u16 type, u16 dpl); 245 void set_idt_entry(int vec, void *addr, int dpl); 246 void set_idt_sel(int vec, u16 sel); 247 void set_idt_dpl(int vec, u16 dpl); 248 void set_gdt_entry(int sel, unsigned long base, u32 limit, u8 access, u8 gran); 249 void set_gdt_entry_base(int sel, unsigned long base); 250 void clear_tss_busy(int sel); 251 void load_gdt_tss(size_t tss_offset); 252 void set_intr_alt_stack(int e, void *fn); 253 void print_current_tss_info(void); 254 handler handle_exception(u8 v, handler fn); 255 void unhandled_exception(struct ex_regs *regs, bool cpu); 256 const char* exception_mnemonic(int vector); 257 258 bool test_for_exception(unsigned int ex, void (*trigger_func)(void *data), 259 void *data); 260 void __set_exception_jmpbuf(jmp_buf *addr); 261 #define set_exception_jmpbuf(jmpbuf) \ 262 (setjmp(jmpbuf) ? : (__set_exception_jmpbuf(&(jmpbuf)), 0)) 263 264 static inline void *get_idt_addr(idt_entry_t *entry) 265 { 266 uintptr_t addr = entry->offset0 | ((u32)entry->offset1 << 16); 267 #ifdef __x86_64__ 268 addr |= (u64)entry->offset2 << 32; 269 #endif 270 return (void *)addr; 271 } 272 273 extern gdt_entry_t *get_gdt_entry(u16 sel); 274 extern gdt_entry_t *get_tss_descr(void); 275 gdt_entry_t *get_ldt_descr(void); 276 277 extern unsigned long get_gdt_entry_base(gdt_entry_t *entry); 278 extern unsigned long get_gdt_entry_limit(gdt_entry_t *entry); 279 280 #define __asm_safe(fep, insn, inputs...) \ 281 ({ \ 282 asm volatile(__ASM_TRY(fep, "1f") \ 283 insn "\n\t" \ 284 "1:\n\t" \ 285 : \ 286 : inputs \ 287 : "memory"); \ 288 exception_vector(); \ 289 }) 290 291 #define asm_safe(insn, inputs...) \ 292 __asm_safe("", insn, inputs) 293 294 #define asm_fep_safe(insn, inputs...) \ 295 __asm_safe_out1(KVM_FEP, insn,, inputs) 296 297 #define __asm_safe_out1(fep, insn, output, inputs...) \ 298 ({ \ 299 asm volatile(__ASM_TRY(fep, "1f") \ 300 insn "\n\t" \ 301 "1:\n\t" \ 302 : output \ 303 : inputs \ 304 : "memory"); \ 305 exception_vector(); \ 306 }) 307 308 #define asm_safe_out1(insn, output, inputs...) \ 309 __asm_safe_out1("", insn, output, inputs) 310 311 #define asm_fep_safe_out1(insn, output, inputs...) \ 312 __asm_safe_out1(KVM_FEP, insn, output, inputs) 313 314 #define __asm_safe_out2(fep, insn, output1, output2, inputs...) \ 315 ({ \ 316 asm volatile(__ASM_TRY(fep, "1f") \ 317 insn "\n\t" \ 318 "1:\n\t" \ 319 : output1, output2 \ 320 : inputs \ 321 : "memory"); \ 322 exception_vector(); \ 323 }) 324 325 #define asm_safe_out2(fep, insn, output1, output2, inputs...) \ 326 __asm_safe_out2("", insn, output1, output2, inputs) 327 328 #define asm_fep_safe_out2(insn, output1, output2, inputs...) \ 329 __asm_safe_out2(KVM_FEP, insn, output1, output2, inputs) 330 331 #define __asm_safe_report(want, insn, inputs...) \ 332 do { \ 333 int vector = asm_safe(insn, inputs); \ 334 \ 335 report(vector == want, "Expected %s on '%s', got %s", \ 336 want ? exception_mnemonic(want) : "SUCCESS", \ 337 insn, \ 338 vector ? exception_mnemonic(vector) : "SUCCESS"); \ 339 } while (0) 340 341 #define asm_safe_report(insn, inputs...) \ 342 __asm_safe_report(0, insn, inputs) 343 344 #define asm_safe_report_ex __asm_safe_report 345 346 #endif 347