1 #include "libcflat.h" 2 #include "desc.h" 3 #include "processor.h" 4 #include "smp.h" 5 #include <setjmp.h> 6 #include "apic-defs.h" 7 8 /* Boot-related data structures */ 9 10 /* IDT and IDT descriptor */ 11 idt_entry_t boot_idt[256] = {0}; 12 13 struct descriptor_table_ptr idt_descr = { 14 .limit = sizeof(boot_idt) - 1, 15 .base = (unsigned long)boot_idt, 16 }; 17 18 #ifndef __x86_64__ 19 /* GDT, TSS and descriptors */ 20 gdt_entry_t gdt[TSS_MAIN / 8 + MAX_TEST_CPUS * 2] = { 21 { 0, 0, 0, .type_limit_flags = 0x0000}, /* 0x00 null */ 22 {0xffff, 0, 0, .type_limit_flags = 0xcf9b}, /* flat 32-bit code segment */ 23 {0xffff, 0, 0, .type_limit_flags = 0xcf93}, /* flat 32-bit data segment */ 24 {0xffff, 0, 0, .type_limit_flags = 0xcf1b}, /* flat 32-bit code segment, not present */ 25 { 0, 0, 0, .type_limit_flags = 0x0000}, /* TSS for task gates */ 26 {0xffff, 0, 0, .type_limit_flags = 0x8f9b}, /* 16-bit code segment */ 27 {0xffff, 0, 0, .type_limit_flags = 0x8f93}, /* 16-bit data segment */ 28 {0xffff, 0, 0, .type_limit_flags = 0xcffb}, /* 32-bit code segment (user) */ 29 {0xffff, 0, 0, .type_limit_flags = 0xcff3}, /* 32-bit data segment (user) */ 30 }; 31 32 tss32_t tss[MAX_TEST_CPUS] = {0}; 33 #else 34 gdt_entry_t gdt[TSS_MAIN / 8 + MAX_TEST_CPUS * 2] = { 35 { 0, 0, 0, .type_limit_flags = 0x0000}, /* 0x00 null */ 36 {0xffff, 0, 0, .type_limit_flags = 0xaf9b}, /* 0x08 64-bit code segment */ 37 {0xffff, 0, 0, .type_limit_flags = 0xcf93}, /* 0x10 32/64-bit data segment */ 38 {0xffff, 0, 0, .type_limit_flags = 0xaf1b}, /* 0x18 64-bit code segment, not present */ 39 {0xffff, 0, 0, .type_limit_flags = 0xcf9b}, /* 0x20 32-bit code segment */ 40 {0xffff, 0, 0, .type_limit_flags = 0x8f9b}, /* 0x28 16-bit code segment */ 41 {0xffff, 0, 0, .type_limit_flags = 0x8f93}, /* 0x30 16-bit data segment */ 42 {0xffff, 0, 0, .type_limit_flags = 0xcffb}, /* 0x38 32-bit code segment (user) */ 43 {0xffff, 0, 0, .type_limit_flags = 0xcff3}, /* 0x40 32/64-bit data segment (user) */ 44 {0xffff, 0, 0, .type_limit_flags = 0xaffb}, /* 0x48 64-bit code segment (user) */ 45 }; 46 47 tss64_t tss[MAX_TEST_CPUS] = {0}; 48 #endif 49 50 struct descriptor_table_ptr gdt_descr = { 51 .limit = sizeof(gdt) - 1, 52 .base = (unsigned long)gdt, 53 }; 54 55 #ifndef __x86_64__ 56 __attribute__((regparm(1))) 57 #endif 58 void do_handle_exception(struct ex_regs *regs); 59 60 /* 61 * Fill an idt_entry_t or call gate entry, clearing e_sz bytes first. 62 * 63 * This can be used for both IDT entries and call gate entries, since the gate 64 * descriptor layout is identical to idt_entry_t, except for the absence of 65 * .offset2 and .reserved fields. To do so, pass in e_sz according to the gate 66 * descriptor size. 67 */ 68 void set_desc_entry(idt_entry_t *e, size_t e_sz, void *addr, 69 u16 sel, u16 type, u16 dpl) 70 { 71 memset(e, 0, e_sz); 72 e->offset0 = (unsigned long)addr; 73 e->selector = sel; 74 e->ist = 0; 75 e->type = type; 76 e->dpl = dpl; 77 e->p = 1; 78 e->offset1 = (unsigned long)addr >> 16; 79 #ifdef __x86_64__ 80 if (e_sz == sizeof(*e)) 81 e->offset2 = (unsigned long)addr >> 32; 82 #endif 83 } 84 85 void set_idt_entry(int vec, void *addr, int dpl) 86 { 87 idt_entry_t *e = &boot_idt[vec]; 88 set_desc_entry(e, sizeof *e, addr, read_cs(), 14, dpl); 89 } 90 91 void set_idt_dpl(int vec, u16 dpl) 92 { 93 idt_entry_t *e = &boot_idt[vec]; 94 e->dpl = dpl; 95 } 96 97 void set_idt_sel(int vec, u16 sel) 98 { 99 idt_entry_t *e = &boot_idt[vec]; 100 e->selector = sel; 101 } 102 103 struct ex_record { 104 unsigned long rip; 105 unsigned long handler; 106 }; 107 108 extern struct ex_record exception_table_start, exception_table_end; 109 110 const char* exception_mnemonic(int vector) 111 { 112 switch(vector) { 113 #define VEC(v) case v##_VECTOR: return "#" #v 114 VEC(DE); 115 VEC(DB); 116 VEC(NMI); 117 VEC(BP); 118 VEC(OF); 119 VEC(BR); 120 VEC(UD); 121 VEC(NM); 122 VEC(DF); 123 VEC(TS); 124 VEC(NP); 125 VEC(SS); 126 VEC(GP); 127 VEC(PF); 128 VEC(MF); 129 VEC(AC); 130 VEC(MC); 131 VEC(XM); 132 VEC(CP); 133 default: return "#??"; 134 #undef VEC 135 } 136 } 137 138 void unhandled_exception(struct ex_regs *regs, bool cpu) 139 { 140 printf("Unhandled %sexception %ld %s at ip %016lx\n", 141 cpu ? "cpu " : "", regs->vector, 142 exception_mnemonic(regs->vector), regs->rip); 143 if (regs->vector == 14) 144 printf("PF at %#lx addr %#lx\n", regs->rip, read_cr2()); 145 146 printf("error_code=%04lx rflags=%08lx cs=%08lx\n" 147 "rax=%016lx rcx=%016lx rdx=%016lx rbx=%016lx\n" 148 "rbp=%016lx rsi=%016lx rdi=%016lx\n" 149 #ifdef __x86_64__ 150 " r8=%016lx r9=%016lx r10=%016lx r11=%016lx\n" 151 "r12=%016lx r13=%016lx r14=%016lx r15=%016lx\n" 152 #endif 153 "cr0=%016lx cr2=%016lx cr3=%016lx cr4=%016lx\n" 154 #ifdef __x86_64__ 155 "cr8=%016lx\n" 156 #endif 157 , 158 regs->error_code, regs->rflags, regs->cs, 159 regs->rax, regs->rcx, regs->rdx, regs->rbx, 160 regs->rbp, regs->rsi, regs->rdi, 161 #ifdef __x86_64__ 162 regs->r8, regs->r9, regs->r10, regs->r11, 163 regs->r12, regs->r13, regs->r14, regs->r15, 164 #endif 165 read_cr0(), read_cr2(), read_cr3(), read_cr4() 166 #ifdef __x86_64__ 167 , read_cr8() 168 #endif 169 ); 170 dump_frame_stack((void*) regs->rip, (void*) regs->rbp); 171 abort(); 172 } 173 174 static void check_exception_table(struct ex_regs *regs) 175 { 176 struct ex_record *ex; 177 178 this_cpu_write_exception_vector(regs->vector); 179 this_cpu_write_exception_rflags_rf((regs->rflags >> 16) & 1); 180 this_cpu_write_exception_error_code(regs->error_code); 181 182 for (ex = &exception_table_start; ex != &exception_table_end; ++ex) { 183 if (ex->rip == regs->rip) { 184 regs->rip = ex->handler; 185 return; 186 } 187 } 188 unhandled_exception(regs, false); 189 } 190 191 static handler exception_handlers[32]; 192 193 handler handle_exception(u8 v, handler fn) 194 { 195 handler old; 196 197 old = exception_handlers[v]; 198 if (v < 32) 199 exception_handlers[v] = fn; 200 return old; 201 } 202 203 #ifndef __x86_64__ 204 __attribute__((regparm(1))) 205 #endif 206 void do_handle_exception(struct ex_regs *regs) 207 { 208 if (regs->vector < 32 && exception_handlers[regs->vector]) { 209 exception_handlers[regs->vector](regs); 210 return; 211 } 212 unhandled_exception(regs, true); 213 } 214 215 #define EX(NAME, N) extern char NAME##_fault; \ 216 asm (".pushsection .text \n\t" \ 217 #NAME"_fault: \n\t" \ 218 "push"W" $0 \n\t" \ 219 "push"W" $"#N" \n\t" \ 220 "jmp __handle_exception \n\t" \ 221 ".popsection") 222 223 #define EX_E(NAME, N) extern char NAME##_fault; \ 224 asm (".pushsection .text \n\t" \ 225 #NAME"_fault: \n\t" \ 226 "push"W" $"#N" \n\t" \ 227 "jmp __handle_exception \n\t" \ 228 ".popsection") 229 230 EX(de, 0); 231 EX(db, 1); 232 EX(nmi, 2); 233 EX(bp, 3); 234 EX(of, 4); 235 EX(br, 5); 236 EX(ud, 6); 237 EX(nm, 7); 238 EX_E(df, 8); 239 EX_E(ts, 10); 240 EX_E(np, 11); 241 EX_E(ss, 12); 242 EX_E(gp, 13); 243 EX_E(pf, 14); 244 EX(mf, 16); 245 EX_E(ac, 17); 246 EX(mc, 18); 247 EX(xm, 19); 248 EX_E(cp, 21); 249 250 asm (".pushsection .text \n\t" 251 "__handle_exception: \n\t" 252 #ifdef __x86_64__ 253 "push %r15; push %r14; push %r13; push %r12 \n\t" 254 "push %r11; push %r10; push %r9; push %r8 \n\t" 255 #endif 256 "push %"R "di; push %"R "si; push %"R "bp; sub $"S", %"R "sp \n\t" 257 "push %"R "bx; push %"R "dx; push %"R "cx; push %"R "ax \n\t" 258 #ifdef __x86_64__ 259 "mov %"R "sp, %"R "di \n\t" 260 #else 261 "mov %"R "sp, %"R "ax \n\t" 262 #endif 263 "call do_handle_exception \n\t" 264 "pop %"R "ax; pop %"R "cx; pop %"R "dx; pop %"R "bx \n\t" 265 "add $"S", %"R "sp; pop %"R "bp; pop %"R "si; pop %"R "di \n\t" 266 #ifdef __x86_64__ 267 "pop %r8; pop %r9; pop %r10; pop %r11 \n\t" 268 "pop %r12; pop %r13; pop %r14; pop %r15 \n\t" 269 #endif 270 "add $"S", %"R "sp \n\t" 271 "add $"S", %"R "sp \n\t" 272 "iret"W" \n\t" 273 ".popsection"); 274 275 static void *idt_handlers[32] = { 276 [0] = &de_fault, 277 [1] = &db_fault, 278 [2] = &nmi_fault, 279 [3] = &bp_fault, 280 [4] = &of_fault, 281 [5] = &br_fault, 282 [6] = &ud_fault, 283 [7] = &nm_fault, 284 [8] = &df_fault, 285 [10] = &ts_fault, 286 [11] = &np_fault, 287 [12] = &ss_fault, 288 [13] = &gp_fault, 289 [14] = &pf_fault, 290 [16] = &mf_fault, 291 [17] = &ac_fault, 292 [18] = &mc_fault, 293 [19] = &xm_fault, 294 [21] = &cp_fault, 295 }; 296 297 void setup_idt(void) 298 { 299 int i; 300 static bool idt_initialized = false; 301 302 if (idt_initialized) 303 return; 304 305 idt_initialized = true; 306 for (i = 0; i < 32; i++) { 307 if (!idt_handlers[i]) 308 continue; 309 310 set_idt_entry(i, idt_handlers[i], 0); 311 handle_exception(i, check_exception_table); 312 } 313 } 314 315 void load_idt(void) 316 { 317 lidt(&idt_descr); 318 } 319 320 unsigned exception_vector(void) 321 { 322 return this_cpu_read_exception_vector(); 323 } 324 325 unsigned exception_error_code(void) 326 { 327 return this_cpu_read_exception_error_code(); 328 } 329 330 bool exception_rflags_rf(void) 331 { 332 return this_cpu_read_exception_rflags_rf() & 1; 333 } 334 335 static char intr_alt_stack[4096]; 336 337 void set_gdt_entry(int sel, unsigned long base, u32 limit, u8 type, u8 flags) 338 { 339 gdt_entry_t *entry = &gdt[sel >> 3]; 340 341 /* Setup the descriptor base address */ 342 entry->base1 = (base & 0xFFFF); 343 entry->base2 = (base >> 16) & 0xFF; 344 entry->base3 = (base >> 24) & 0xFF; 345 346 /* Setup the descriptor limits, type and flags */ 347 entry->limit1 = (limit & 0xFFFF); 348 entry->type_limit_flags = ((limit & 0xF0000) >> 8) | ((flags & 0xF0) << 8) | type; 349 350 #ifdef __x86_64__ 351 if (!entry->s) { 352 struct system_desc64 *entry16 = (struct system_desc64 *)entry; 353 entry16->zero = 0; 354 entry16->base4 = base >> 32; 355 } 356 #endif 357 } 358 359 void load_gdt_tss(size_t tss_offset) 360 { 361 lgdt(&gdt_descr); 362 ltr(tss_offset); 363 } 364 365 #ifndef __x86_64__ 366 void set_gdt_task_gate(u16 sel, u16 tss_sel) 367 { 368 set_gdt_entry(sel, tss_sel, 0, 0x85, 0); // task, present 369 } 370 371 void set_idt_task_gate(int vec, u16 sel) 372 { 373 idt_entry_t *e = &boot_idt[vec]; 374 375 memset(e, 0, sizeof *e); 376 377 e->selector = sel; 378 e->ist = 0; 379 e->type = 5; 380 e->dpl = 0; 381 e->p = 1; 382 } 383 384 /* 385 * 0 - main task 386 * 1 - interrupt task 387 */ 388 389 tss32_t tss_intr; 390 391 void setup_tss32(void) 392 { 393 u16 desc_size = sizeof(tss32_t); 394 395 tss[0].cr3 = read_cr3(); 396 tss_intr.cr3 = read_cr3(); 397 tss_intr.ss0 = tss_intr.ss1 = tss_intr.ss2 = 0x10; 398 tss_intr.esp = tss_intr.esp0 = tss_intr.esp1 = tss_intr.esp2 = 399 (u32)intr_alt_stack + 4096; 400 tss_intr.cs = 0x08; 401 tss_intr.ds = tss_intr.es = tss_intr.fs = tss_intr.ss = 0x10; 402 tss_intr.gs = read_gs(); 403 tss_intr.iomap_base = (u16)desc_size; 404 set_gdt_entry(TSS_INTR, (u32)&tss_intr, desc_size - 1, 0x89, 0); 405 } 406 407 void set_intr_task_gate(int e, void *fn) 408 { 409 tss_intr.eip = (u32)fn; 410 set_idt_task_gate(e, TSS_INTR); 411 } 412 413 void setup_alt_stack(void) 414 { 415 setup_tss32(); 416 } 417 418 void set_intr_alt_stack(int e, void *fn) 419 { 420 set_intr_task_gate(e, fn); 421 } 422 423 void print_current_tss_info(void) 424 { 425 u16 tr = str(); 426 427 if (tr != TSS_MAIN && tr != TSS_INTR) 428 printf("Unknown TSS %x\n", tr); 429 else 430 printf("TR=%x (%s) Main TSS back link %x. Intr TSS back link %x\n", 431 tr, tr ? "interrupt" : "main", tss[0].prev, tss_intr.prev); 432 } 433 #else 434 void set_intr_alt_stack(int e, void *addr) 435 { 436 set_idt_entry(e, addr, 0); 437 boot_idt[e].ist = 1; 438 } 439 440 void setup_alt_stack(void) 441 { 442 tss[0].ist1 = (u64)intr_alt_stack + 4096; 443 } 444 #endif 445 446 static bool exception; 447 static jmp_buf *exception_jmpbuf; 448 449 static void exception_handler_longjmp(void) 450 { 451 longjmp(*exception_jmpbuf, 1); 452 } 453 454 static void exception_handler(struct ex_regs *regs) 455 { 456 /* longjmp must happen after iret, so do not do it now. */ 457 exception = true; 458 regs->rip = (unsigned long)&exception_handler_longjmp; 459 regs->cs = read_cs(); 460 } 461 462 bool test_for_exception(unsigned int ex, void (*trigger_func)(void *data), 463 void *data) 464 { 465 handler old; 466 jmp_buf jmpbuf; 467 int ret; 468 469 old = handle_exception(ex, exception_handler); 470 ret = set_exception_jmpbuf(jmpbuf); 471 if (ret == 0) 472 trigger_func(data); 473 handle_exception(ex, old); 474 return ret; 475 } 476 477 void __set_exception_jmpbuf(jmp_buf *addr) 478 { 479 exception_jmpbuf = addr; 480 } 481 482 gdt_entry_t *get_tss_descr(void) 483 { 484 struct descriptor_table_ptr gdt_ptr; 485 gdt_entry_t *gdt; 486 487 sgdt(&gdt_ptr); 488 gdt = (gdt_entry_t *)gdt_ptr.base; 489 return &gdt[str() / 8]; 490 } 491 492 unsigned long get_gdt_entry_base(gdt_entry_t *entry) 493 { 494 unsigned long base; 495 base = entry->base1 | ((u32)entry->base2 << 16) | ((u32)entry->base3 << 24); 496 #ifdef __x86_64__ 497 if (!entry->s) { 498 base |= (u64)((struct system_desc64 *)entry)->base4 << 32; 499 } 500 #endif 501 return base; 502 } 503 504 unsigned long get_gdt_entry_limit(gdt_entry_t *entry) 505 { 506 unsigned long limit; 507 limit = entry->limit1 | ((u32)entry->limit2 << 16); 508 if (entry->g) { 509 limit = (limit << 12) | 0xFFF; 510 } 511 return limit; 512 } 513