1 /*- 2 * Copyright (c) 2014 Andrew Turner 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 * 26 */ 27 28 #include "opt_ddb.h" 29 30 #include <sys/cdefs.h> 31 __FBSDID("$FreeBSD$"); 32 33 #include <sys/param.h> 34 #include <sys/systm.h> 35 #include <sys/kernel.h> 36 #include <sys/ktr.h> 37 #include <sys/lock.h> 38 #include <sys/mutex.h> 39 #include <sys/proc.h> 40 #include <sys/ptrace.h> 41 #include <sys/syscall.h> 42 #include <sys/sysent.h> 43 #ifdef KDB 44 #include <sys/kdb.h> 45 #endif 46 47 #include <vm/vm.h> 48 #include <vm/pmap.h> 49 #include <vm/vm_kern.h> 50 #include <vm/vm_map.h> 51 #include <vm/vm_param.h> 52 #include <vm/vm_extern.h> 53 54 #include <machine/frame.h> 55 #include <machine/md_var.h> 56 #include <machine/pcb.h> 57 #include <machine/pcpu.h> 58 #include <machine/undefined.h> 59 60 #ifdef KDTRACE_HOOKS 61 #include <sys/dtrace_bsd.h> 62 #endif 63 64 #ifdef VFP 65 #include <machine/vfp.h> 66 #endif 67 68 #ifdef KDB 69 #include <machine/db_machdep.h> 70 #endif 71 72 #ifdef DDB 73 #include <ddb/ddb.h> 74 #include <ddb/db_sym.h> 75 #endif 76 77 /* Called from exception.S */ 78 void do_el1h_sync(struct thread *, struct trapframe *); 79 void do_el0_sync(struct thread *, struct trapframe *); 80 void do_el0_error(struct trapframe *); 81 void do_serror(struct trapframe *); 82 void unhandled_exception(struct trapframe *); 83 84 static void print_gp_register(const char *name, uint64_t value); 85 static void print_registers(struct trapframe *frame); 86 87 int (*dtrace_invop_jump_addr)(struct trapframe *); 88 89 typedef void (abort_handler)(struct thread *, struct trapframe *, uint64_t, 90 uint64_t, int); 91 92 static abort_handler align_abort; 93 static abort_handler data_abort; 94 static abort_handler external_abort; 95 96 static abort_handler *abort_handlers[] = { 97 [ISS_DATA_DFSC_TF_L0] = data_abort, 98 [ISS_DATA_DFSC_TF_L1] = data_abort, 99 [ISS_DATA_DFSC_TF_L2] = data_abort, 100 [ISS_DATA_DFSC_TF_L3] = data_abort, 101 [ISS_DATA_DFSC_AFF_L1] = data_abort, 102 [ISS_DATA_DFSC_AFF_L2] = data_abort, 103 [ISS_DATA_DFSC_AFF_L3] = data_abort, 104 [ISS_DATA_DFSC_PF_L1] = data_abort, 105 [ISS_DATA_DFSC_PF_L2] = data_abort, 106 [ISS_DATA_DFSC_PF_L3] = data_abort, 107 [ISS_DATA_DFSC_ALIGN] = align_abort, 108 [ISS_DATA_DFSC_EXT] = external_abort, 109 [ISS_DATA_DFSC_EXT_L0] = external_abort, 110 [ISS_DATA_DFSC_EXT_L1] = external_abort, 111 [ISS_DATA_DFSC_EXT_L2] = external_abort, 112 [ISS_DATA_DFSC_EXT_L3] = external_abort, 113 [ISS_DATA_DFSC_ECC] = external_abort, 114 [ISS_DATA_DFSC_ECC_L0] = external_abort, 115 [ISS_DATA_DFSC_ECC_L1] = external_abort, 116 [ISS_DATA_DFSC_ECC_L2] = external_abort, 117 [ISS_DATA_DFSC_ECC_L3] = external_abort, 118 }; 119 120 static __inline void 121 call_trapsignal(struct thread *td, int sig, int code, void *addr, int trapno) 122 { 123 ksiginfo_t ksi; 124 125 ksiginfo_init_trap(&ksi); 126 ksi.ksi_signo = sig; 127 ksi.ksi_code = code; 128 ksi.ksi_addr = addr; 129 ksi.ksi_trapno = trapno; 130 trapsignal(td, &ksi); 131 } 132 133 int 134 cpu_fetch_syscall_args(struct thread *td) 135 { 136 struct proc *p; 137 register_t *ap, *dst_ap; 138 struct syscall_args *sa; 139 140 p = td->td_proc; 141 sa = &td->td_sa; 142 ap = td->td_frame->tf_x; 143 dst_ap = &sa->args[0]; 144 145 sa->code = td->td_frame->tf_x[8]; 146 sa->original_code = sa->code; 147 148 if (__predict_false(sa->code == SYS_syscall || sa->code == SYS___syscall)) { 149 sa->code = *ap++; 150 } else { 151 *dst_ap++ = *ap++; 152 } 153 154 if (__predict_false(sa->code >= p->p_sysent->sv_size)) 155 sa->callp = &p->p_sysent->sv_table[0]; 156 else 157 sa->callp = &p->p_sysent->sv_table[sa->code]; 158 159 KASSERT(sa->callp->sy_narg <= nitems(sa->args), 160 ("Syscall %d takes too many arguments", sa->code)); 161 162 memcpy(dst_ap, ap, (MAXARGS - 1) * sizeof(register_t)); 163 164 td->td_retval[0] = 0; 165 td->td_retval[1] = 0; 166 167 return (0); 168 } 169 170 #include "../../kern/subr_syscall.c" 171 172 /* 173 * Test for fault generated by given access instruction in 174 * bus_peek_<foo> or bus_poke_<foo> bus function. 175 */ 176 extern uint32_t generic_bs_peek_1f, generic_bs_peek_2f; 177 extern uint32_t generic_bs_peek_4f, generic_bs_peek_8f; 178 extern uint32_t generic_bs_poke_1f, generic_bs_poke_2f; 179 extern uint32_t generic_bs_poke_4f, generic_bs_poke_8f; 180 181 static bool 182 test_bs_fault(void *addr) 183 { 184 return (addr == &generic_bs_peek_1f || 185 addr == &generic_bs_peek_2f || 186 addr == &generic_bs_peek_4f || 187 addr == &generic_bs_peek_8f || 188 addr == &generic_bs_poke_1f || 189 addr == &generic_bs_poke_2f || 190 addr == &generic_bs_poke_4f || 191 addr == &generic_bs_poke_8f); 192 } 193 194 static void 195 svc_handler(struct thread *td, struct trapframe *frame) 196 { 197 198 if ((frame->tf_esr & ESR_ELx_ISS_MASK) == 0) { 199 syscallenter(td); 200 syscallret(td); 201 } else { 202 call_trapsignal(td, SIGILL, ILL_ILLOPN, (void *)frame->tf_elr, 203 ESR_ELx_EXCEPTION(frame->tf_esr)); 204 userret(td, frame); 205 } 206 } 207 208 static void 209 align_abort(struct thread *td, struct trapframe *frame, uint64_t esr, 210 uint64_t far, int lower) 211 { 212 if (!lower) { 213 print_registers(frame); 214 print_gp_register("far", far); 215 printf(" esr: %.8lx\n", esr); 216 panic("Misaligned access from kernel space!"); 217 } 218 219 call_trapsignal(td, SIGBUS, BUS_ADRALN, (void *)frame->tf_elr, 220 ESR_ELx_EXCEPTION(frame->tf_esr)); 221 userret(td, frame); 222 } 223 224 225 static void 226 external_abort(struct thread *td, struct trapframe *frame, uint64_t esr, 227 uint64_t far, int lower) 228 { 229 230 /* 231 * Try to handle synchronous external aborts caused by 232 * bus_space_peek() and/or bus_space_poke() functions. 233 */ 234 if (!lower && test_bs_fault((void *)frame->tf_elr)) { 235 frame->tf_elr = (uint64_t)generic_bs_fault; 236 return; 237 } 238 239 print_registers(frame); 240 print_gp_register("far", far); 241 panic("Unhandled EL%d external data abort", lower ? 0: 1); 242 } 243 244 static void 245 data_abort(struct thread *td, struct trapframe *frame, uint64_t esr, 246 uint64_t far, int lower) 247 { 248 struct vm_map *map; 249 struct proc *p; 250 struct pcb *pcb; 251 vm_prot_t ftype; 252 int error, sig, ucode; 253 #ifdef KDB 254 bool handled; 255 #endif 256 257 /* 258 * According to the ARMv8-A rev. A.g, B2.10.5 "Load-Exclusive 259 * and Store-Exclusive instruction usage restrictions", state 260 * of the exclusive monitors after data abort exception is unknown. 261 */ 262 clrex(); 263 264 #ifdef KDB 265 if (kdb_active) { 266 kdb_reenter(); 267 return; 268 } 269 #endif 270 271 pcb = td->td_pcb; 272 p = td->td_proc; 273 if (lower) 274 map = &p->p_vmspace->vm_map; 275 else { 276 intr_enable(); 277 278 /* We received a TBI/PAC/etc. fault from the kernel */ 279 if (!ADDR_IS_CANONICAL(far)) { 280 error = KERN_INVALID_ADDRESS; 281 goto bad_far; 282 } 283 284 /* The top bit tells us which range to use */ 285 if (ADDR_IS_KERNEL(far)) { 286 map = kernel_map; 287 } else { 288 map = &p->p_vmspace->vm_map; 289 if (map == NULL) 290 map = kernel_map; 291 } 292 } 293 294 /* 295 * Try to handle translation, access flag, and permission faults. 296 * Translation faults may occur as a result of the required 297 * break-before-make sequence used when promoting or demoting 298 * superpages. Such faults must not occur while holding the pmap lock, 299 * or pmap_fault() will recurse on that lock. 300 */ 301 if ((lower || map == kernel_map || pcb->pcb_onfault != 0) && 302 pmap_fault(map->pmap, esr, far) == KERN_SUCCESS) 303 return; 304 305 KASSERT(td->td_md.md_spinlock_count == 0, 306 ("data abort with spinlock held")); 307 if (td->td_critnest != 0 || WITNESS_CHECK(WARN_SLEEPOK | 308 WARN_GIANTOK, NULL, "Kernel page fault") != 0) { 309 print_registers(frame); 310 print_gp_register("far", far); 311 printf(" esr: %.8lx\n", esr); 312 panic("data abort in critical section or under mutex"); 313 } 314 315 switch (ESR_ELx_EXCEPTION(esr)) { 316 case EXCP_INSN_ABORT: 317 case EXCP_INSN_ABORT_L: 318 ftype = VM_PROT_EXECUTE; 319 break; 320 default: 321 ftype = (esr & ISS_DATA_WnR) == 0 ? VM_PROT_READ : 322 VM_PROT_WRITE; 323 break; 324 } 325 326 /* Fault in the page. */ 327 error = vm_fault_trap(map, far, ftype, VM_FAULT_NORMAL, &sig, &ucode); 328 if (error != KERN_SUCCESS) { 329 bad_far: 330 if (lower) { 331 call_trapsignal(td, sig, ucode, (void *)far, 332 ESR_ELx_EXCEPTION(esr)); 333 } else { 334 if (td->td_intr_nesting_level == 0 && 335 pcb->pcb_onfault != 0) { 336 frame->tf_x[0] = error; 337 frame->tf_elr = pcb->pcb_onfault; 338 return; 339 } 340 341 printf("Fatal data abort:\n"); 342 print_registers(frame); 343 print_gp_register("far", far); 344 printf(" esr: %.8lx\n", esr); 345 346 #ifdef KDB 347 if (debugger_on_trap) { 348 kdb_why = KDB_WHY_TRAP; 349 handled = kdb_trap(ESR_ELx_EXCEPTION(esr), 0, 350 frame); 351 kdb_why = KDB_WHY_UNSET; 352 if (handled) 353 return; 354 } 355 #endif 356 panic("vm_fault failed: %lx error %d", 357 frame->tf_elr, error); 358 } 359 } 360 361 if (lower) 362 userret(td, frame); 363 } 364 365 static void 366 print_gp_register(const char *name, uint64_t value) 367 { 368 #if defined(DDB) 369 c_db_sym_t sym; 370 const char *sym_name; 371 db_expr_t sym_value; 372 db_expr_t offset; 373 #endif 374 375 printf(" %s: %16lx", name, value); 376 #if defined(DDB) 377 /* If this looks like a kernel address try to find the symbol */ 378 if (value >= VM_MIN_KERNEL_ADDRESS) { 379 sym = db_search_symbol(value, DB_STGY_ANY, &offset); 380 if (sym != C_DB_SYM_NULL) { 381 db_symbol_values(sym, &sym_name, &sym_value); 382 printf(" (%s + %lx)", sym_name, offset); 383 } 384 } 385 #endif 386 printf("\n"); 387 } 388 389 static void 390 print_registers(struct trapframe *frame) 391 { 392 char name[4]; 393 u_int reg; 394 395 for (reg = 0; reg < nitems(frame->tf_x); reg++) { 396 snprintf(name, sizeof(name), "%sx%d", (reg < 10) ? " " : "", 397 reg); 398 print_gp_register(name, frame->tf_x[reg]); 399 } 400 printf(" sp: %16lx\n", frame->tf_sp); 401 print_gp_register(" lr", frame->tf_lr); 402 print_gp_register("elr", frame->tf_elr); 403 printf("spsr: %8x\n", frame->tf_spsr); 404 } 405 406 void 407 do_el1h_sync(struct thread *td, struct trapframe *frame) 408 { 409 uint32_t exception; 410 uint64_t esr, far; 411 int dfsc; 412 413 /* Read the esr register to get the exception details */ 414 esr = frame->tf_esr; 415 exception = ESR_ELx_EXCEPTION(esr); 416 417 #ifdef KDTRACE_HOOKS 418 if (dtrace_trap_func != NULL && (*dtrace_trap_func)(frame, exception)) 419 return; 420 #endif 421 422 CTR4(KTR_TRAP, 423 "do_el1_sync: curthread: %p, esr %lx, elr: %lx, frame: %p", td, 424 esr, frame->tf_elr, frame); 425 426 /* 427 * Enable debug exceptions if we aren't already handling one. They will 428 * be masked again in the exception handler's epilogue. 429 */ 430 if (exception != EXCP_BRK && exception != EXCP_WATCHPT_EL1 && 431 exception != EXCP_SOFTSTP_EL1) 432 dbg_enable(); 433 434 switch (exception) { 435 case EXCP_FP_SIMD: 436 case EXCP_TRAP_FP: 437 #ifdef VFP 438 if ((td->td_pcb->pcb_fpflags & PCB_FP_KERN) != 0) { 439 vfp_restore_state(); 440 } else 441 #endif 442 { 443 print_registers(frame); 444 printf(" esr: %.8lx\n", esr); 445 panic("VFP exception in the kernel"); 446 } 447 break; 448 case EXCP_INSN_ABORT: 449 case EXCP_DATA_ABORT: 450 far = READ_SPECIALREG(far_el1); 451 dfsc = esr & ISS_DATA_DFSC_MASK; 452 if (dfsc < nitems(abort_handlers) && 453 abort_handlers[dfsc] != NULL) { 454 abort_handlers[dfsc](td, frame, esr, far, 0); 455 } else { 456 print_registers(frame); 457 print_gp_register("far", far); 458 printf(" esr: %.8lx\n", esr); 459 panic("Unhandled EL1 %s abort: %x", 460 exception == EXCP_INSN_ABORT ? "instruction" : 461 "data", dfsc); 462 } 463 break; 464 case EXCP_BRK: 465 #ifdef KDTRACE_HOOKS 466 if ((esr & ESR_ELx_ISS_MASK) == 0x40d && \ 467 dtrace_invop_jump_addr != 0) { 468 dtrace_invop_jump_addr(frame); 469 break; 470 } 471 #endif 472 #ifdef KDB 473 kdb_trap(exception, 0, frame); 474 #else 475 panic("No debugger in kernel."); 476 #endif 477 break; 478 case EXCP_WATCHPT_EL1: 479 case EXCP_SOFTSTP_EL1: 480 #ifdef KDB 481 kdb_trap(exception, 0, frame); 482 #else 483 panic("No debugger in kernel."); 484 #endif 485 break; 486 case EXCP_UNKNOWN: 487 if (undef_insn(1, frame)) 488 break; 489 /* FALLTHROUGH */ 490 default: 491 print_registers(frame); 492 print_gp_register("far", READ_SPECIALREG(far_el1)); 493 panic("Unknown kernel exception %x esr_el1 %lx", exception, 494 esr); 495 } 496 } 497 498 void 499 do_el0_sync(struct thread *td, struct trapframe *frame) 500 { 501 pcpu_bp_harden bp_harden; 502 uint32_t exception; 503 uint64_t esr, far; 504 int dfsc; 505 506 /* Check we have a sane environment when entering from userland */ 507 KASSERT((uintptr_t)get_pcpu() >= VM_MIN_KERNEL_ADDRESS, 508 ("Invalid pcpu address from userland: %p (tpidr %lx)", 509 get_pcpu(), READ_SPECIALREG(tpidr_el1))); 510 511 esr = frame->tf_esr; 512 exception = ESR_ELx_EXCEPTION(esr); 513 switch (exception) { 514 case EXCP_INSN_ABORT_L: 515 far = READ_SPECIALREG(far_el1); 516 517 /* 518 * Userspace may be trying to train the branch predictor to 519 * attack the kernel. If we are on a CPU affected by this 520 * call the handler to clear the branch predictor state. 521 */ 522 if (far > VM_MAXUSER_ADDRESS) { 523 bp_harden = PCPU_GET(bp_harden); 524 if (bp_harden != NULL) 525 bp_harden(); 526 } 527 break; 528 case EXCP_UNKNOWN: 529 case EXCP_DATA_ABORT_L: 530 case EXCP_DATA_ABORT: 531 case EXCP_WATCHPT_EL0: 532 far = READ_SPECIALREG(far_el1); 533 break; 534 } 535 intr_enable(); 536 537 CTR4(KTR_TRAP, 538 "do_el0_sync: curthread: %p, esr %lx, elr: %lx, frame: %p", td, esr, 539 frame->tf_elr, frame); 540 541 switch (exception) { 542 case EXCP_FP_SIMD: 543 case EXCP_TRAP_FP: 544 #ifdef VFP 545 vfp_restore_state(); 546 #else 547 panic("VFP exception in userland"); 548 #endif 549 break; 550 case EXCP_SVC32: 551 case EXCP_SVC64: 552 svc_handler(td, frame); 553 break; 554 case EXCP_INSN_ABORT_L: 555 case EXCP_DATA_ABORT_L: 556 case EXCP_DATA_ABORT: 557 dfsc = esr & ISS_DATA_DFSC_MASK; 558 if (dfsc < nitems(abort_handlers) && 559 abort_handlers[dfsc] != NULL) 560 abort_handlers[dfsc](td, frame, esr, far, 1); 561 else { 562 print_registers(frame); 563 print_gp_register("far", far); 564 printf(" esr: %.8lx\n", esr); 565 panic("Unhandled EL0 %s abort: %x", 566 exception == EXCP_INSN_ABORT_L ? "instruction" : 567 "data", dfsc); 568 } 569 break; 570 case EXCP_UNKNOWN: 571 if (!undef_insn(0, frame)) 572 call_trapsignal(td, SIGILL, ILL_ILLTRP, (void *)far, 573 exception); 574 userret(td, frame); 575 break; 576 case EXCP_SP_ALIGN: 577 call_trapsignal(td, SIGBUS, BUS_ADRALN, (void *)frame->tf_sp, 578 exception); 579 userret(td, frame); 580 break; 581 case EXCP_PC_ALIGN: 582 call_trapsignal(td, SIGBUS, BUS_ADRALN, (void *)frame->tf_elr, 583 exception); 584 userret(td, frame); 585 break; 586 case EXCP_BRKPT_EL0: 587 case EXCP_BRK: 588 #ifdef COMPAT_FREEBSD32 589 case EXCP_BRKPT_32: 590 #endif /* COMPAT_FREEBSD32 */ 591 call_trapsignal(td, SIGTRAP, TRAP_BRKPT, (void *)frame->tf_elr, 592 exception); 593 userret(td, frame); 594 break; 595 case EXCP_WATCHPT_EL0: 596 call_trapsignal(td, SIGTRAP, TRAP_TRACE, (void *)far, 597 exception); 598 userret(td, frame); 599 break; 600 case EXCP_MSR: 601 /* 602 * The CPU can raise EXCP_MSR when userspace executes an mrs 603 * instruction to access a special register userspace doesn't 604 * have access to. 605 */ 606 if (!undef_insn(0, frame)) 607 call_trapsignal(td, SIGILL, ILL_PRVOPC, 608 (void *)frame->tf_elr, exception); 609 userret(td, frame); 610 break; 611 case EXCP_SOFTSTP_EL0: 612 td->td_frame->tf_spsr &= ~PSR_SS; 613 td->td_pcb->pcb_flags &= ~PCB_SINGLE_STEP; 614 WRITE_SPECIALREG(mdscr_el1, 615 READ_SPECIALREG(mdscr_el1) & ~DBG_MDSCR_SS); 616 call_trapsignal(td, SIGTRAP, TRAP_TRACE, 617 (void *)frame->tf_elr, exception); 618 userret(td, frame); 619 break; 620 default: 621 call_trapsignal(td, SIGBUS, BUS_OBJERR, (void *)frame->tf_elr, 622 exception); 623 userret(td, frame); 624 break; 625 } 626 627 KASSERT((td->td_pcb->pcb_fpflags & ~PCB_FP_USERMASK) == 0, 628 ("Kernel VFP flags set while entering userspace")); 629 KASSERT( 630 td->td_pcb->pcb_fpusaved == &td->td_pcb->pcb_fpustate, 631 ("Kernel VFP state in use when entering userspace")); 632 } 633 634 /* 635 * TODO: We will need to handle these later when we support ARMv8.2 RAS. 636 */ 637 void 638 do_serror(struct trapframe *frame) 639 { 640 uint64_t esr, far; 641 642 far = READ_SPECIALREG(far_el1); 643 esr = frame->tf_esr; 644 645 print_registers(frame); 646 print_gp_register("far", far); 647 printf(" esr: %.8lx\n", esr); 648 panic("Unhandled System Error"); 649 } 650 651 void 652 unhandled_exception(struct trapframe *frame) 653 { 654 uint64_t esr, far; 655 656 far = READ_SPECIALREG(far_el1); 657 esr = frame->tf_esr; 658 659 print_registers(frame); 660 print_gp_register("far", far); 661 printf(" esr: %.8lx\n", esr); 662 panic("Unhandled exception"); 663 } 664