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 <sys/cdefs.h> 29 __FBSDID("$FreeBSD$"); 30 31 #include <sys/param.h> 32 #include <sys/systm.h> 33 #include <sys/kernel.h> 34 #include <sys/ktr.h> 35 #include <sys/lock.h> 36 #include <sys/mutex.h> 37 #include <sys/proc.h> 38 #include <sys/ptrace.h> 39 #include <sys/syscall.h> 40 #include <sys/sysent.h> 41 #ifdef KDB 42 #include <sys/kdb.h> 43 #endif 44 45 #include <vm/vm.h> 46 #include <vm/pmap.h> 47 #include <vm/vm_kern.h> 48 #include <vm/vm_map.h> 49 #include <vm/vm_param.h> 50 #include <vm/vm_extern.h> 51 52 #include <machine/frame.h> 53 #include <machine/pcb.h> 54 #include <machine/pcpu.h> 55 #include <machine/undefined.h> 56 57 #ifdef KDTRACE_HOOKS 58 #include <sys/dtrace_bsd.h> 59 #endif 60 61 #ifdef VFP 62 #include <machine/vfp.h> 63 #endif 64 65 #ifdef KDB 66 #include <machine/db_machdep.h> 67 #endif 68 69 #ifdef DDB 70 #include <ddb/db_output.h> 71 #endif 72 73 extern register_t fsu_intr_fault; 74 75 /* Called from exception.S */ 76 void do_el1h_sync(struct thread *, struct trapframe *); 77 void do_el0_sync(struct thread *, struct trapframe *); 78 void do_el0_error(struct trapframe *); 79 void do_serror(struct trapframe *); 80 void unhandled_exception(struct trapframe *); 81 82 static void print_registers(struct trapframe *frame); 83 84 int (*dtrace_invop_jump_addr)(struct trapframe *); 85 86 typedef void (abort_handler)(struct thread *, struct trapframe *, uint64_t, 87 uint64_t, int); 88 89 static abort_handler align_abort; 90 static abort_handler data_abort; 91 92 static abort_handler *abort_handlers[] = { 93 [ISS_DATA_DFSC_TF_L0] = data_abort, 94 [ISS_DATA_DFSC_TF_L1] = data_abort, 95 [ISS_DATA_DFSC_TF_L2] = data_abort, 96 [ISS_DATA_DFSC_TF_L3] = data_abort, 97 [ISS_DATA_DFSC_AFF_L1] = data_abort, 98 [ISS_DATA_DFSC_AFF_L2] = data_abort, 99 [ISS_DATA_DFSC_AFF_L3] = data_abort, 100 [ISS_DATA_DFSC_PF_L1] = data_abort, 101 [ISS_DATA_DFSC_PF_L2] = data_abort, 102 [ISS_DATA_DFSC_PF_L3] = data_abort, 103 [ISS_DATA_DFSC_ALIGN] = align_abort, 104 }; 105 106 static __inline void 107 call_trapsignal(struct thread *td, int sig, int code, void *addr) 108 { 109 ksiginfo_t ksi; 110 111 ksiginfo_init_trap(&ksi); 112 ksi.ksi_signo = sig; 113 ksi.ksi_code = code; 114 ksi.ksi_addr = addr; 115 trapsignal(td, &ksi); 116 } 117 118 int 119 cpu_fetch_syscall_args(struct thread *td) 120 { 121 struct proc *p; 122 register_t *ap; 123 struct syscall_args *sa; 124 int nap; 125 126 nap = 8; 127 p = td->td_proc; 128 ap = td->td_frame->tf_x; 129 sa = &td->td_sa; 130 131 sa->code = td->td_frame->tf_x[8]; 132 133 if (sa->code == SYS_syscall || sa->code == SYS___syscall) { 134 sa->code = *ap++; 135 nap--; 136 } 137 138 if (sa->code >= p->p_sysent->sv_size) 139 sa->callp = &p->p_sysent->sv_table[0]; 140 else 141 sa->callp = &p->p_sysent->sv_table[sa->code]; 142 143 sa->narg = sa->callp->sy_narg; 144 memcpy(sa->args, ap, nap * sizeof(register_t)); 145 if (sa->narg > nap) 146 panic("ARM64TODO: Could we have more than 8 args?"); 147 148 td->td_retval[0] = 0; 149 td->td_retval[1] = 0; 150 151 return (0); 152 } 153 154 #include "../../kern/subr_syscall.c" 155 156 static void 157 svc_handler(struct thread *td, struct trapframe *frame) 158 { 159 160 if ((frame->tf_esr & ESR_ELx_ISS_MASK) == 0) { 161 syscallenter(td); 162 syscallret(td); 163 } else { 164 call_trapsignal(td, SIGILL, ILL_ILLOPN, (void *)frame->tf_elr); 165 userret(td, frame); 166 } 167 } 168 169 static void 170 align_abort(struct thread *td, struct trapframe *frame, uint64_t esr, 171 uint64_t far, int lower) 172 { 173 if (!lower) { 174 print_registers(frame); 175 printf(" far: %16lx\n", far); 176 printf(" esr: %.8lx\n", esr); 177 panic("Misaligned access from kernel space!"); 178 } 179 180 call_trapsignal(td, SIGBUS, BUS_ADRALN, (void *)frame->tf_elr); 181 userret(td, frame); 182 } 183 184 static void 185 data_abort(struct thread *td, struct trapframe *frame, uint64_t esr, 186 uint64_t far, int lower) 187 { 188 struct vm_map *map; 189 struct proc *p; 190 struct pcb *pcb; 191 vm_prot_t ftype; 192 int error, sig, ucode; 193 #ifdef KDB 194 bool handled; 195 #endif 196 197 /* 198 * According to the ARMv8-A rev. A.g, B2.10.5 "Load-Exclusive 199 * and Store-Exclusive instruction usage restrictions", state 200 * of the exclusive monitors after data abort exception is unknown. 201 */ 202 clrex(); 203 204 #ifdef KDB 205 if (kdb_active) { 206 kdb_reenter(); 207 return; 208 } 209 #endif 210 211 pcb = td->td_pcb; 212 p = td->td_proc; 213 if (lower) 214 map = &p->p_vmspace->vm_map; 215 else { 216 intr_enable(); 217 218 /* The top bit tells us which range to use */ 219 if (far >= VM_MAXUSER_ADDRESS) { 220 map = kernel_map; 221 } else { 222 map = &p->p_vmspace->vm_map; 223 if (map == NULL) 224 map = kernel_map; 225 } 226 } 227 228 /* 229 * Try to handle translation, access flag, and permission faults. 230 * Translation faults may occur as a result of the required 231 * break-before-make sequence used when promoting or demoting 232 * superpages. Such faults must not occur while holding the pmap lock, 233 * or pmap_fault() will recurse on that lock. 234 */ 235 if ((lower || map == kernel_map || pcb->pcb_onfault != 0) && 236 pmap_fault(map->pmap, esr, far) == KERN_SUCCESS) 237 return; 238 239 KASSERT(td->td_md.md_spinlock_count == 0, 240 ("data abort with spinlock held")); 241 if (td->td_critnest != 0 || WITNESS_CHECK(WARN_SLEEPOK | 242 WARN_GIANTOK, NULL, "Kernel page fault") != 0) { 243 print_registers(frame); 244 printf(" far: %16lx\n", far); 245 printf(" esr: %.8lx\n", esr); 246 panic("data abort in critical section or under mutex"); 247 } 248 249 switch (ESR_ELx_EXCEPTION(esr)) { 250 case EXCP_INSN_ABORT: 251 case EXCP_INSN_ABORT_L: 252 ftype = VM_PROT_EXECUTE; 253 break; 254 default: 255 ftype = (esr & ISS_DATA_WnR) == 0 ? VM_PROT_READ : 256 VM_PROT_READ | VM_PROT_WRITE; 257 break; 258 } 259 260 /* Fault in the page. */ 261 error = vm_fault_trap(map, far, ftype, VM_FAULT_NORMAL, &sig, &ucode); 262 if (error != KERN_SUCCESS) { 263 if (lower) { 264 call_trapsignal(td, sig, ucode, (void *)far); 265 } else { 266 if (td->td_intr_nesting_level == 0 && 267 pcb->pcb_onfault != 0) { 268 frame->tf_x[0] = error; 269 frame->tf_elr = pcb->pcb_onfault; 270 return; 271 } 272 273 printf("Fatal data abort:\n"); 274 print_registers(frame); 275 printf(" far: %16lx\n", far); 276 printf(" esr: %.8lx\n", esr); 277 278 #ifdef KDB 279 if (debugger_on_trap) { 280 kdb_why = KDB_WHY_TRAP; 281 handled = kdb_trap(ESR_ELx_EXCEPTION(esr), 0, 282 frame); 283 kdb_why = KDB_WHY_UNSET; 284 if (handled) 285 return; 286 } 287 #endif 288 panic("vm_fault failed: %lx", frame->tf_elr); 289 } 290 } 291 292 if (lower) 293 userret(td, frame); 294 } 295 296 static void 297 print_registers(struct trapframe *frame) 298 { 299 u_int reg; 300 301 for (reg = 0; reg < nitems(frame->tf_x); reg++) { 302 printf(" %sx%d: %16lx\n", (reg < 10) ? " " : "", reg, 303 frame->tf_x[reg]); 304 } 305 printf(" sp: %16lx\n", frame->tf_sp); 306 printf(" lr: %16lx\n", frame->tf_lr); 307 printf(" elr: %16lx\n", frame->tf_elr); 308 printf("spsr: %8x\n", frame->tf_spsr); 309 } 310 311 void 312 do_el1h_sync(struct thread *td, struct trapframe *frame) 313 { 314 struct trapframe *oframe; 315 uint32_t exception; 316 uint64_t esr, far; 317 int dfsc; 318 319 /* Read the esr register to get the exception details */ 320 esr = frame->tf_esr; 321 exception = ESR_ELx_EXCEPTION(esr); 322 323 #ifdef KDTRACE_HOOKS 324 if (dtrace_trap_func != NULL && (*dtrace_trap_func)(frame, exception)) 325 return; 326 #endif 327 328 CTR4(KTR_TRAP, 329 "do_el1_sync: curthread: %p, esr %lx, elr: %lx, frame: %p", td, 330 esr, frame->tf_elr, frame); 331 332 oframe = td->td_frame; 333 334 switch (exception) { 335 case EXCP_BRK: 336 case EXCP_WATCHPT_EL1: 337 case EXCP_SOFTSTP_EL1: 338 break; 339 default: 340 td->td_frame = frame; 341 break; 342 } 343 344 switch(exception) { 345 case EXCP_FP_SIMD: 346 case EXCP_TRAP_FP: 347 #ifdef VFP 348 if ((td->td_pcb->pcb_fpflags & PCB_FP_KERN) != 0) { 349 vfp_restore_state(); 350 } else 351 #endif 352 { 353 print_registers(frame); 354 printf(" esr: %.8lx\n", esr); 355 panic("VFP exception in the kernel"); 356 } 357 break; 358 case EXCP_INSN_ABORT: 359 case EXCP_DATA_ABORT: 360 far = READ_SPECIALREG(far_el1); 361 dfsc = esr & ISS_DATA_DFSC_MASK; 362 if (dfsc < nitems(abort_handlers) && 363 abort_handlers[dfsc] != NULL) { 364 abort_handlers[dfsc](td, frame, esr, far, 0); 365 } else { 366 print_registers(frame); 367 printf(" far: %16lx\n", far); 368 printf(" esr: %.8lx\n", esr); 369 panic("Unhandled EL1 %s abort: %x", 370 exception == EXCP_INSN_ABORT ? "instruction" : 371 "data", dfsc); 372 } 373 break; 374 case EXCP_BRK: 375 #ifdef KDTRACE_HOOKS 376 if ((esr & ESR_ELx_ISS_MASK) == 0x40d && \ 377 dtrace_invop_jump_addr != 0) { 378 dtrace_invop_jump_addr(frame); 379 break; 380 } 381 #endif 382 #ifdef KDB 383 kdb_trap(exception, 0, 384 (td->td_frame != NULL) ? td->td_frame : frame); 385 #else 386 panic("No debugger in kernel.\n"); 387 #endif 388 frame->tf_elr += 4; 389 break; 390 case EXCP_WATCHPT_EL1: 391 case EXCP_SOFTSTP_EL1: 392 #ifdef KDB 393 kdb_trap(exception, 0, 394 (td->td_frame != NULL) ? td->td_frame : frame); 395 #else 396 panic("No debugger in kernel.\n"); 397 #endif 398 break; 399 case EXCP_UNKNOWN: 400 if (undef_insn(1, frame)) 401 break; 402 /* FALLTHROUGH */ 403 default: 404 print_registers(frame); 405 printf(" far: %16lx\n", READ_SPECIALREG(far_el1)); 406 panic("Unknown kernel exception %x esr_el1 %lx\n", exception, 407 esr); 408 } 409 410 td->td_frame = oframe; 411 } 412 413 void 414 do_el0_sync(struct thread *td, struct trapframe *frame) 415 { 416 pcpu_bp_harden bp_harden; 417 uint32_t exception; 418 uint64_t esr, far; 419 int dfsc; 420 421 /* Check we have a sane environment when entering from userland */ 422 KASSERT((uintptr_t)get_pcpu() >= VM_MIN_KERNEL_ADDRESS, 423 ("Invalid pcpu address from userland: %p (tpidr %lx)", 424 get_pcpu(), READ_SPECIALREG(tpidr_el1))); 425 426 esr = frame->tf_esr; 427 exception = ESR_ELx_EXCEPTION(esr); 428 switch (exception) { 429 case EXCP_INSN_ABORT_L: 430 far = READ_SPECIALREG(far_el1); 431 432 /* 433 * Userspace may be trying to train the branch predictor to 434 * attack the kernel. If we are on a CPU affected by this 435 * call the handler to clear the branch predictor state. 436 */ 437 if (far > VM_MAXUSER_ADDRESS) { 438 bp_harden = PCPU_GET(bp_harden); 439 if (bp_harden != NULL) 440 bp_harden(); 441 } 442 break; 443 case EXCP_UNKNOWN: 444 case EXCP_DATA_ABORT_L: 445 case EXCP_DATA_ABORT: 446 far = READ_SPECIALREG(far_el1); 447 break; 448 } 449 intr_enable(); 450 451 CTR4(KTR_TRAP, 452 "do_el0_sync: curthread: %p, esr %lx, elr: %lx, frame: %p", td, esr, 453 frame->tf_elr, frame); 454 455 switch(exception) { 456 case EXCP_FP_SIMD: 457 case EXCP_TRAP_FP: 458 #ifdef VFP 459 vfp_restore_state(); 460 #else 461 panic("VFP exception in userland"); 462 #endif 463 break; 464 case EXCP_SVC32: 465 case EXCP_SVC64: 466 svc_handler(td, frame); 467 break; 468 case EXCP_INSN_ABORT_L: 469 case EXCP_DATA_ABORT_L: 470 case EXCP_DATA_ABORT: 471 dfsc = esr & ISS_DATA_DFSC_MASK; 472 if (dfsc < nitems(abort_handlers) && 473 abort_handlers[dfsc] != NULL) 474 abort_handlers[dfsc](td, frame, esr, far, 1); 475 else { 476 print_registers(frame); 477 printf(" far: %16lx\n", far); 478 printf(" esr: %.8lx\n", esr); 479 panic("Unhandled EL0 %s abort: %x", 480 exception == EXCP_INSN_ABORT_L ? "instruction" : 481 "data", dfsc); 482 } 483 break; 484 case EXCP_UNKNOWN: 485 if (!undef_insn(0, frame)) 486 call_trapsignal(td, SIGILL, ILL_ILLTRP, (void *)far); 487 userret(td, frame); 488 break; 489 case EXCP_SP_ALIGN: 490 call_trapsignal(td, SIGBUS, BUS_ADRALN, (void *)frame->tf_sp); 491 userret(td, frame); 492 break; 493 case EXCP_PC_ALIGN: 494 call_trapsignal(td, SIGBUS, BUS_ADRALN, (void *)frame->tf_elr); 495 userret(td, frame); 496 break; 497 case EXCP_BRKPT_EL0: 498 case EXCP_BRK: 499 call_trapsignal(td, SIGTRAP, TRAP_BRKPT, (void *)frame->tf_elr); 500 userret(td, frame); 501 break; 502 case EXCP_MSR: 503 call_trapsignal(td, SIGILL, ILL_PRVOPC, (void *)frame->tf_elr); 504 userret(td, frame); 505 break; 506 case EXCP_SOFTSTP_EL0: 507 td->td_frame->tf_spsr &= ~PSR_SS; 508 td->td_pcb->pcb_flags &= ~PCB_SINGLE_STEP; 509 WRITE_SPECIALREG(mdscr_el1, 510 READ_SPECIALREG(mdscr_el1) & ~DBG_MDSCR_SS); 511 call_trapsignal(td, SIGTRAP, TRAP_TRACE, 512 (void *)frame->tf_elr); 513 userret(td, frame); 514 break; 515 default: 516 call_trapsignal(td, SIGBUS, BUS_OBJERR, (void *)frame->tf_elr); 517 userret(td, frame); 518 break; 519 } 520 521 KASSERT((td->td_pcb->pcb_fpflags & ~PCB_FP_USERMASK) == 0, 522 ("Kernel VFP flags set while entering userspace")); 523 KASSERT( 524 td->td_pcb->pcb_fpusaved == &td->td_pcb->pcb_fpustate, 525 ("Kernel VFP state in use when entering userspace")); 526 } 527 528 /* 529 * TODO: We will need to handle these later when we support ARMv8.2 RAS. 530 */ 531 void 532 do_serror(struct trapframe *frame) 533 { 534 uint64_t esr, far; 535 536 far = READ_SPECIALREG(far_el1); 537 esr = frame->tf_esr; 538 539 print_registers(frame); 540 printf(" far: %16lx\n", far); 541 printf(" esr: %.8lx\n", esr); 542 panic("Unhandled System Error"); 543 } 544 545 void 546 unhandled_exception(struct trapframe *frame) 547 { 548 uint64_t esr, far; 549 550 far = READ_SPECIALREG(far_el1); 551 esr = frame->tf_esr; 552 553 print_registers(frame); 554 printf(" far: %16lx\n", far); 555 printf(" esr: %.8lx\n", esr); 556 panic("Unhandled exception"); 557 } 558