Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]
FreeBSD/Linux Kernel Cross Reference
sys/amd64/amd64/trap.c
Version:
- FREEBSD - FREEBSD-13-STABLE - FREEBSD-13-0 - FREEBSD-12-STABLE - FREEBSD-12-0 - FREEBSD-11-STABLE - FREEBSD-11-0 - FREEBSD-10-STABLE - FREEBSD-10-0 - FREEBSD-9-STABLE - FREEBSD-9-0 - FREEBSD-8-STABLE - FREEBSD-8-0 - FREEBSD-7-STABLE - FREEBSD-7-0 - FREEBSD-6-STABLE - FREEBSD-6-0 - FREEBSD-5-STABLE - FREEBSD-5-0 - FREEBSD-4-STABLE - FREEBSD-3-STABLE - FREEBSD22 - l41 - OPENBSD - linux-2.6 - MK84 - PLAN9 - xnu-8792
SearchContext: - none - 3 - 10
SearchContext: - none - 3 - 10
1 /*- 2 * Copyright (C) 1994, David Greenman 3 * Copyright (c) 1990, 1993 4 * The Regents of the University of California. All rights reserved. 5 * 6 * This code is derived from software contributed to Berkeley by 7 * the University of Utah, and William Jolitz. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. All advertising materials mentioning features or use of this software 18 * must display the following acknowledgement: 19 * This product includes software developed by the University of 20 * California, Berkeley and its contributors. 21 * 4. Neither the name of the University nor the names of its contributors 22 * may be used to endorse or promote products derived from this software 23 * without specific prior written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 28 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 35 * SUCH DAMAGE. 36 * 37 * from: @(#)trap.c 7.4 (Berkeley) 5/13/91 38 */ 39 40 #include <sys/cdefs.h> 41 __FBSDID("$FreeBSD: releng/5.4/sys/amd64/amd64/trap.c 145750 2005-05-01 05:38:14Z dwhite $"); 42 43 /* 44 * AMD64 Trap and System call handling 45 */ 46 47 #include "opt_clock.h" 48 #include "opt_cpu.h" 49 #include "opt_isa.h" 50 #include "opt_ktrace.h" 51 52 #include <sys/param.h> 53 #include <sys/bus.h> 54 #include <sys/systm.h> 55 #include <sys/proc.h> 56 #include <sys/pioctl.h> 57 #include <sys/ptrace.h> 58 #include <sys/kdb.h> 59 #include <sys/kernel.h> 60 #include <sys/ktr.h> 61 #include <sys/lock.h> 62 #include <sys/mutex.h> 63 #include <sys/resourcevar.h> 64 #include <sys/signalvar.h> 65 #include <sys/syscall.h> 66 #include <sys/sysctl.h> 67 #include <sys/sysent.h> 68 #include <sys/uio.h> 69 #include <sys/vmmeter.h> 70 #ifdef KTRACE 71 #include <sys/ktrace.h> 72 #endif 73 74 #include <vm/vm.h> 75 #include <vm/vm_param.h> 76 #include <vm/pmap.h> 77 #include <vm/vm_kern.h> 78 #include <vm/vm_map.h> 79 #include <vm/vm_page.h> 80 #include <vm/vm_extern.h> 81 82 #include <machine/cpu.h> 83 #include <machine/intr_machdep.h> 84 #include <machine/md_var.h> 85 #include <machine/pcb.h> 86 #ifdef SMP 87 #include <machine/smp.h> 88 #endif 89 #include <machine/tss.h> 90 91 extern void trap(struct trapframe frame); 92 extern void syscall(struct trapframe frame); 93 94 static int trap_pfault(struct trapframe *, int); 95 static void trap_fatal(struct trapframe *, vm_offset_t); 96 void dblfault_handler(void); 97 98 #define MAX_TRAP_MSG 28 99 static char *trap_msg[] = { 100 "", /* 0 unused */ 101 "privileged instruction fault", /* 1 T_PRIVINFLT */ 102 "", /* 2 unused */ 103 "breakpoint instruction fault", /* 3 T_BPTFLT */ 104 "", /* 4 unused */ 105 "", /* 5 unused */ 106 "arithmetic trap", /* 6 T_ARITHTRAP */ 107 "", /* 7 unused */ 108 "", /* 8 unused */ 109 "general protection fault", /* 9 T_PROTFLT */ 110 "trace trap", /* 10 T_TRCTRAP */ 111 "", /* 11 unused */ 112 "page fault", /* 12 T_PAGEFLT */ 113 "", /* 13 unused */ 114 "alignment fault", /* 14 T_ALIGNFLT */ 115 "", /* 15 unused */ 116 "", /* 16 unused */ 117 "", /* 17 unused */ 118 "integer divide fault", /* 18 T_DIVIDE */ 119 "non-maskable interrupt trap", /* 19 T_NMI */ 120 "overflow trap", /* 20 T_OFLOW */ 121 "FPU bounds check fault", /* 21 T_BOUND */ 122 "FPU device not available", /* 22 T_DNA */ 123 "double fault", /* 23 T_DOUBLEFLT */ 124 "FPU operand fetch fault", /* 24 T_FPOPFLT */ 125 "invalid TSS fault", /* 25 T_TSSFLT */ 126 "segment not present fault", /* 26 T_SEGNPFLT */ 127 "stack fault", /* 27 T_STKFLT */ 128 "machine check trap", /* 28 T_MCHK */ 129 }; 130 131 #ifdef KDB 132 static int kdb_on_nmi = 1; 133 SYSCTL_INT(_machdep, OID_AUTO, kdb_on_nmi, CTLFLAG_RW, 134 &kdb_on_nmi, 0, "Go to KDB on NMI"); 135 #endif 136 static int panic_on_nmi = 1; 137 SYSCTL_INT(_machdep, OID_AUTO, panic_on_nmi, CTLFLAG_RW, 138 &panic_on_nmi, 0, "Panic on NMI"); 139 140 #ifdef WITNESS 141 extern char *syscallnames[]; 142 #endif 143 144 #ifdef DEVICE_POLLING 145 extern u_int32_t poll_in_trap; 146 extern int ether_poll(int count); 147 #endif /* DEVICE_POLLING */ 148 149 /* 150 * Exception, fault, and trap interface to the FreeBSD kernel. 151 * This common code is called from assembly language IDT gate entry 152 * routines that prepare a suitable stack frame, and restore this 153 * frame after the exception has been processed. 154 */ 155 156 void 157 trap(frame) 158 struct trapframe frame; 159 { 160 struct thread *td = curthread; 161 struct proc *p = td->td_proc; 162 u_int sticks = 0; 163 int i = 0, ucode = 0, type, code; 164 165 atomic_add_int(&cnt.v_trap, 1); 166 type = frame.tf_trapno; 167 168 #ifdef KDB_STOP_NMI 169 /* Handler for NMI IPIs used for debugging */ 170 if (type == T_NMI) { 171 if (ipi_nmi_handler() == 0) 172 goto out; 173 } 174 #endif /* KDB_STOP_NMI */ 175 176 #ifdef KDB 177 if (kdb_active) { 178 kdb_reenter(); 179 goto out; 180 } 181 #endif 182 183 if ((frame.tf_rflags & PSL_I) == 0) { 184 /* 185 * Buggy application or kernel code has disabled 186 * interrupts and then trapped. Enabling interrupts 187 * now is wrong, but it is better than running with 188 * interrupts disabled until they are accidentally 189 * enabled later. 190 */ 191 if (ISPL(frame.tf_cs) == SEL_UPL) 192 printf( 193 "pid %ld (%s): trap %d with interrupts disabled\n", 194 (long)curproc->p_pid, curproc->p_comm, type); 195 else if (type != T_BPTFLT && type != T_TRCTRAP) { 196 /* 197 * XXX not quite right, since this may be for a 198 * multiple fault in user mode. 199 */ 200 printf("kernel trap %d with interrupts disabled\n", 201 type); 202 /* 203 * We shouldn't enable interrupts while in a critical 204 * section. 205 */ 206 if (td->td_critnest == 0) 207 enable_intr(); 208 } 209 } 210 211 code = frame.tf_err; 212 if (type == T_PAGEFLT) { 213 /* 214 * If we get a page fault while in a critical section, then 215 * it is most likely a fatal kernel page fault. The kernel 216 * is already going to panic trying to get a sleep lock to 217 * do the VM lookup, so just consider it a fatal trap so the 218 * kernel can print out a useful trap message and even get 219 * to the debugger. 220 */ 221 if (td->td_critnest != 0) 222 trap_fatal(&frame, frame.tf_addr); 223 } 224 225 #ifdef DEVICE_POLLING 226 if (poll_in_trap) 227 ether_poll(poll_in_trap); 228 #endif /* DEVICE_POLLING */ 229 230 if (ISPL(frame.tf_cs) == SEL_UPL) { 231 /* user trap */ 232 233 sticks = td->td_sticks; 234 td->td_frame = &frame; 235 if (td->td_ucred != p->p_ucred) 236 cred_update_thread(td); 237 238 switch (type) { 239 case T_PRIVINFLT: /* privileged instruction fault */ 240 ucode = type; 241 i = SIGILL; 242 break; 243 244 case T_BPTFLT: /* bpt instruction fault */ 245 case T_TRCTRAP: /* trace trap */ 246 enable_intr(); 247 frame.tf_rflags &= ~PSL_T; 248 i = SIGTRAP; 249 break; 250 251 case T_ARITHTRAP: /* arithmetic trap */ 252 ucode = fputrap(); 253 if (ucode == -1) 254 goto userout; 255 i = SIGFPE; 256 break; 257 258 case T_PROTFLT: /* general protection fault */ 259 case T_STKFLT: /* stack fault */ 260 case T_SEGNPFLT: /* segment not present fault */ 261 case T_TSSFLT: /* invalid TSS fault */ 262 case T_DOUBLEFLT: /* double fault */ 263 default: 264 ucode = code + BUS_SEGM_FAULT ; 265 i = SIGBUS; 266 break; 267 268 case T_PAGEFLT: /* page fault */ 269 if (td->td_pflags & TDP_SA) 270 thread_user_enter(td); 271 i = trap_pfault(&frame, TRUE); 272 if (i == -1) 273 goto userout; 274 if (i == 0) 275 goto user; 276 277 ucode = T_PAGEFLT; 278 break; 279 280 case T_DIVIDE: /* integer divide fault */ 281 ucode = FPE_INTDIV; 282 i = SIGFPE; 283 break; 284 285 #ifdef DEV_ISA 286 case T_NMI: 287 /* machine/parity/power fail/"kitchen sink" faults */ 288 /* XXX Giant */ 289 if (isa_nmi(code) == 0) { 290 #ifdef KDB 291 /* 292 * NMI can be hooked up to a pushbutton 293 * for debugging. 294 */ 295 if (kdb_on_nmi) { 296 printf ("NMI ... going to debugger\n"); 297 kdb_trap(type, 0, &frame); 298 } 299 #endif /* KDB */ 300 goto userout; 301 } else if (panic_on_nmi) 302 panic("NMI indicates hardware failure"); 303 break; 304 #endif /* DEV_ISA */ 305 306 case T_OFLOW: /* integer overflow fault */ 307 ucode = FPE_INTOVF; 308 i = SIGFPE; 309 break; 310 311 case T_BOUND: /* bounds check fault */ 312 ucode = FPE_FLTSUB; 313 i = SIGFPE; 314 break; 315 316 case T_DNA: 317 /* transparent fault (due to context switch "late") */ 318 if (fpudna()) 319 goto userout; 320 i = SIGFPE; 321 ucode = FPE_FPU_NP_TRAP; 322 break; 323 324 case T_FPOPFLT: /* FPU operand fetch fault */ 325 ucode = T_FPOPFLT; 326 i = SIGILL; 327 break; 328 329 case T_XMMFLT: /* SIMD floating-point exception */ 330 ucode = 0; /* XXX */ 331 i = SIGFPE; 332 break; 333 } 334 } else { 335 /* kernel trap */ 336 337 KASSERT(cold || td->td_ucred != NULL, 338 ("kernel trap doesn't have ucred")); 339 switch (type) { 340 case T_PAGEFLT: /* page fault */ 341 (void) trap_pfault(&frame, FALSE); 342 goto out; 343 344 case T_DNA: 345 /* 346 * The kernel is apparently using fpu for copying. 347 * XXX this should be fatal unless the kernel has 348 * registered such use. 349 */ 350 if (fpudna()) { 351 printf("fpudna in kernel mode!\n"); 352 goto out; 353 } 354 break; 355 356 case T_STKFLT: /* stack fault */ 357 break; 358 359 case T_PROTFLT: /* general protection fault */ 360 case T_SEGNPFLT: /* segment not present fault */ 361 if (td->td_intr_nesting_level != 0) 362 break; 363 364 /* 365 * Invalid segment selectors and out of bounds 366 * %eip's and %esp's can be set up in user mode. 367 * This causes a fault in kernel mode when the 368 * kernel tries to return to user mode. We want 369 * to get this fault so that we can fix the 370 * problem here and not have to check all the 371 * selectors and pointers when the user changes 372 * them. 373 */ 374 if (frame.tf_rip == (long)doreti_iret) { 375 frame.tf_rip = (long)doreti_iret_fault; 376 goto out; 377 } 378 if (PCPU_GET(curpcb)->pcb_onfault != NULL) { 379 frame.tf_rip = 380 (long)PCPU_GET(curpcb)->pcb_onfault; 381 goto out; 382 } 383 break; 384 385 case T_TSSFLT: 386 /* 387 * PSL_NT can be set in user mode and isn't cleared 388 * automatically when the kernel is entered. This 389 * causes a TSS fault when the kernel attempts to 390 * `iret' because the TSS link is uninitialized. We 391 * want to get this fault so that we can fix the 392 * problem here and not every time the kernel is 393 * entered. 394 */ 395 if (frame.tf_rflags & PSL_NT) { 396 frame.tf_rflags &= ~PSL_NT; 397 goto out; 398 } 399 break; 400 401 case T_TRCTRAP: /* trace trap */ 402 /* 403 * Ignore debug register trace traps due to 404 * accesses in the user's address space, which 405 * can happen under several conditions such as 406 * if a user sets a watchpoint on a buffer and 407 * then passes that buffer to a system call. 408 * We still want to get TRCTRAPS for addresses 409 * in kernel space because that is useful when 410 * debugging the kernel. 411 */ 412 if (user_dbreg_trap()) { 413 /* 414 * Reset breakpoint bits because the 415 * processor doesn't 416 */ 417 /* XXX check upper bits here */ 418 load_dr6(rdr6() & 0xfffffff0); 419 goto out; 420 } 421 /* 422 * FALLTHROUGH (TRCTRAP kernel mode, kernel address) 423 */ 424 case T_BPTFLT: 425 /* 426 * If KDB is enabled, let it handle the debugger trap. 427 * Otherwise, debugger traps "can't happen". 428 */ 429 #ifdef KDB 430 /* XXX Giant */ 431 if (kdb_trap(type, 0, &frame)) 432 goto out; 433 #endif 434 break; 435 436 #ifdef DEV_ISA 437 case T_NMI: 438 /* XXX Giant */ 439 /* machine/parity/power fail/"kitchen sink" faults */ 440 if (isa_nmi(code) == 0) { 441 #ifdef KDB 442 /* 443 * NMI can be hooked up to a pushbutton 444 * for debugging. 445 */ 446 if (kdb_on_nmi) { 447 printf ("NMI ... going to debugger\n"); 448 kdb_trap(type, 0, &frame); 449 } 450 #endif /* KDB */ 451 goto out; 452 } else if (panic_on_nmi == 0) 453 goto out; 454 /* FALLTHROUGH */ 455 #endif /* DEV_ISA */ 456 } 457 458 trap_fatal(&frame, 0); 459 goto out; 460 } 461 462 /* Translate fault for emulators (e.g. Linux) */ 463 if (*p->p_sysent->sv_transtrap) 464 i = (*p->p_sysent->sv_transtrap)(i, type); 465 466 trapsignal(td, i, ucode); 467 468 #ifdef DEBUG 469 if (type <= MAX_TRAP_MSG) { 470 uprintf("fatal process exception: %s", 471 trap_msg[type]); 472 if ((type == T_PAGEFLT) || (type == T_PROTFLT)) 473 uprintf(", fault VA = 0x%lx", frame.tf_addr); 474 uprintf("\n"); 475 } 476 #endif 477 478 user: 479 userret(td, &frame, sticks); 480 mtx_assert(&Giant, MA_NOTOWNED); 481 userout: 482 out: 483 return; 484 } 485 486 static int 487 trap_pfault(frame, usermode) 488 struct trapframe *frame; 489 int usermode; 490 { 491 vm_offset_t va; 492 struct vmspace *vm = NULL; 493 vm_map_t map = 0; 494 int rv = 0; 495 vm_prot_t ftype; 496 struct thread *td = curthread; 497 struct proc *p = td->td_proc; 498 vm_offset_t eva = frame->tf_addr; 499 500 va = trunc_page(eva); 501 if (va >= KERNBASE) { 502 /* 503 * Don't allow user-mode faults in kernel address space. 504 */ 505 if (usermode) 506 goto nogo; 507 508 map = kernel_map; 509 } else { 510 /* 511 * This is a fault on non-kernel virtual memory. 512 * vm is initialized above to NULL. If curproc is NULL 513 * or curproc->p_vmspace is NULL the fault is fatal. 514 */ 515 if (p != NULL) 516 vm = p->p_vmspace; 517 518 if (vm == NULL) 519 goto nogo; 520 521 map = &vm->vm_map; 522 } 523 524 if (frame->tf_err & PGEX_W) 525 ftype = VM_PROT_WRITE; 526 else 527 ftype = VM_PROT_READ; 528 529 if (map != kernel_map) { 530 /* 531 * Keep swapout from messing with us during this 532 * critical time. 533 */ 534 PROC_LOCK(p); 535 ++p->p_lock; 536 PROC_UNLOCK(p); 537 538 /* Fault in the user page: */ 539 rv = vm_fault(map, va, ftype, 540 (ftype & VM_PROT_WRITE) ? VM_FAULT_DIRTY 541 : VM_FAULT_NORMAL); 542 543 PROC_LOCK(p); 544 --p->p_lock; 545 PROC_UNLOCK(p); 546 } else { 547 /* 548 * Don't have to worry about process locking or stacks in the 549 * kernel. 550 */ 551 rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL); 552 } 553 if (rv == KERN_SUCCESS) 554 return (0); 555 nogo: 556 if (!usermode) { 557 if (td->td_intr_nesting_level == 0 && 558 PCPU_GET(curpcb)->pcb_onfault != NULL) { 559 frame->tf_rip = (long)PCPU_GET(curpcb)->pcb_onfault; 560 return (0); 561 } 562 trap_fatal(frame, eva); 563 return (-1); 564 } 565 566 return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV); 567 } 568 569 static void 570 trap_fatal(frame, eva) 571 struct trapframe *frame; 572 vm_offset_t eva; 573 { 574 int code, type, ss; 575 long esp; 576 struct soft_segment_descriptor softseg; 577 578 code = frame->tf_err; 579 type = frame->tf_trapno; 580 sdtossd(&gdt[IDXSEL(frame->tf_cs & 0xffff)], &softseg); 581 582 if (type <= MAX_TRAP_MSG) 583 printf("\n\nFatal trap %d: %s while in %s mode\n", 584 type, trap_msg[type], 585 ISPL(frame->tf_cs) == SEL_UPL ? "user" : "kernel"); 586 #ifdef SMP 587 /* two separate prints in case of a trap on an unmapped page */ 588 printf("cpuid = %d; ", PCPU_GET(cpuid)); 589 printf("apic id = %02x\n", PCPU_GET(apic_id)); 590 #endif 591 if (type == T_PAGEFLT) { 592 printf("fault virtual address = 0x%lx\n", eva); 593 printf("fault code = %s %s, %s\n", 594 code & PGEX_U ? "user" : "supervisor", 595 code & PGEX_W ? "write" : "read", 596 code & PGEX_P ? "protection violation" : "page not present"); 597 } 598 printf("instruction pointer = 0x%lx:0x%lx\n", 599 frame->tf_cs & 0xffff, frame->tf_rip); 600 if (ISPL(frame->tf_cs) == SEL_UPL) { 601 ss = frame->tf_ss & 0xffff; 602 esp = frame->tf_rsp; 603 } else { 604 ss = GSEL(GDATA_SEL, SEL_KPL); 605 esp = (long)&frame->tf_rsp; 606 } 607 printf("stack pointer = 0x%x:0x%lx\n", ss, esp); 608 printf("frame pointer = 0x%x:0x%lx\n", ss, frame->tf_rbp); 609 printf("code segment = base 0x%lx, limit 0x%lx, type 0x%x\n", 610 softseg.ssd_base, softseg.ssd_limit, softseg.ssd_type); 611 printf(" = DPL %d, pres %d, long %d, def32 %d, gran %d\n", 612 softseg.ssd_dpl, softseg.ssd_p, softseg.ssd_long, softseg.ssd_def32, 613 softseg.ssd_gran); 614 printf("processor eflags = "); 615 if (frame->tf_rflags & PSL_T) 616 printf("trace trap, "); 617 if (frame->tf_rflags & PSL_I) 618 printf("interrupt enabled, "); 619 if (frame->tf_rflags & PSL_NT) 620 printf("nested task, "); 621 if (frame->tf_rflags & PSL_RF) 622 printf("resume, "); 623 printf("IOPL = %ld\n", (frame->tf_rflags & PSL_IOPL) >> 12); 624 printf("current process = "); 625 if (curproc) { 626 printf("%lu (%s)\n", 627 (u_long)curproc->p_pid, curproc->p_comm ? 628 curproc->p_comm : ""); 629 } else { 630 printf("Idle\n"); 631 } 632 633 #ifdef KDB 634 if (kdb_trap(type, 0, frame)) 635 return; 636 #endif 637 printf("trap number = %d\n", type); 638 if (type <= MAX_TRAP_MSG) 639 panic("%s", trap_msg[type]); 640 else 641 panic("unknown/reserved trap"); 642 } 643 644 /* 645 * Double fault handler. Called when a fault occurs while writing 646 * a frame for a trap/exception onto the stack. This usually occurs 647 * when the stack overflows (such is the case with infinite recursion, 648 * for example). 649 */ 650 void 651 dblfault_handler() 652 { 653 printf("\nFatal double fault\n"); 654 #ifdef SMP 655 /* two separate prints in case of a trap on an unmapped page */ 656 printf("cpuid = %d; ", PCPU_GET(cpuid)); 657 printf("apic id = %02x\n", PCPU_GET(apic_id)); 658 #endif 659 panic("double fault"); 660 } 661 662 /* 663 * syscall - system call request C handler 664 * 665 * A system call is essentially treated as a trap. 666 */ 667 void 668 syscall(frame) 669 struct trapframe frame; 670 { 671 caddr_t params; 672 struct sysent *callp; 673 struct thread *td = curthread; 674 struct proc *p = td->td_proc; 675 register_t orig_tf_rflags; 676 u_int sticks; 677 int error; 678 int narg; 679 register_t args[8]; 680 register_t *argp; 681 u_int code; 682 int reg, regcnt; 683 684 /* 685 * note: PCPU_LAZY_INC() can only be used if we can afford 686 * occassional inaccuracy in the count. 687 */ 688 PCPU_LAZY_INC(cnt.v_syscall); 689 690 #ifdef DIAGNOSTIC 691 if (ISPL(frame.tf_cs) != SEL_UPL) { 692 mtx_lock(&Giant); /* try to stabilize the system XXX */ 693 panic("syscall"); 694 /* NOT REACHED */ 695 mtx_unlock(&Giant); 696 } 697 #endif 698 699 reg = 0; 700 regcnt = 6; 701 sticks = td->td_sticks; 702 td->td_frame = &frame; 703 if (td->td_ucred != p->p_ucred) 704 cred_update_thread(td); 705 if (p->p_flag & P_SA) 706 thread_user_enter(td); 707 params = (caddr_t)frame.tf_rsp + sizeof(register_t); 708 code = frame.tf_rax; 709 orig_tf_rflags = frame.tf_rflags; 710 711 if (p->p_sysent->sv_prepsyscall) { 712 /* 713 * The prep code is MP aware. 714 */ 715 (*p->p_sysent->sv_prepsyscall)(&frame, (int *)args, &code, ¶ms); 716 } else { 717 if (code == SYS_syscall || code == SYS___syscall) { 718 code = frame.tf_rdi; 719 reg++; 720 regcnt--; 721 } 722 } 723 724 if (p->p_sysent->sv_mask) 725 code &= p->p_sysent->sv_mask; 726 727 if (code >= p->p_sysent->sv_size) 728 callp = &p->p_sysent->sv_table[0]; 729 else 730 callp = &p->p_sysent->sv_table[code]; 731 732 narg = callp->sy_narg & SYF_ARGMASK; 733 734 /* 735 * copyin and the ktrsyscall()/ktrsysret() code is MP-aware 736 */ 737 KASSERT(narg <= sizeof(args) / sizeof(args[0]), 738 ("Too many syscall arguments!")); 739 error = 0; 740 argp = &frame.tf_rdi; 741 argp += reg; 742 bcopy(argp, args, sizeof(args[0]) * regcnt); 743 if (narg > regcnt) { 744 KASSERT(params != NULL, ("copyin args with no params!")); 745 error = copyin(params, &args[regcnt], 746 (narg - regcnt) * sizeof(args[0])); 747 } 748 argp = &args[0]; 749 750 #ifdef KTRACE 751 if (KTRPOINT(td, KTR_SYSCALL)) 752 ktrsyscall(code, narg, argp); 753 #endif 754 755 CTR4(KTR_SYSC, "syscall enter thread %p pid %d proc %s code %d", td, 756 td->td_proc->p_pid, td->td_proc->p_comm, code); 757 758 if (error == 0) { 759 td->td_retval[0] = 0; 760 td->td_retval[1] = frame.tf_rdx; 761 762 STOPEVENT(p, S_SCE, narg); 763 764 PTRACESTOP_SC(p, td, S_PT_SCE); 765 766 if ((callp->sy_narg & SYF_MPSAFE) == 0) { 767 mtx_lock(&Giant); 768 error = (*callp->sy_call)(td, argp); 769 mtx_unlock(&Giant); 770 } else 771 error = (*callp->sy_call)(td, argp); 772 } 773 774 switch (error) { 775 case 0: 776 frame.tf_rax = td->td_retval[0]; 777 frame.tf_rdx = td->td_retval[1]; 778 frame.tf_rflags &= ~PSL_C; 779 break; 780 781 case ERESTART: 782 /* 783 * Reconstruct pc, we know that 'syscall' is 2 bytes. 784 * We have to do a full context restore so that %r10 785 * (which was holding the value of %rcx) is restored for 786 * the next iteration. 787 */ 788 frame.tf_rip -= frame.tf_err; 789 frame.tf_r10 = frame.tf_rcx; 790 td->td_pcb->pcb_flags |= PCB_FULLCTX; 791 break; 792 793 case EJUSTRETURN: 794 break; 795 796 default: 797 if (p->p_sysent->sv_errsize) { 798 if (error >= p->p_sysent->sv_errsize) 799 error = -1; /* XXX */ 800 else 801 error = p->p_sysent->sv_errtbl[error]; 802 } 803 frame.tf_rax = error; 804 frame.tf_rflags |= PSL_C; 805 break; 806 } 807 808 /* 809 * Traced syscall. 810 */ 811 if (orig_tf_rflags & PSL_T) { 812 frame.tf_rflags &= ~PSL_T; 813 trapsignal(td, SIGTRAP, 0); 814 } 815 816 /* 817 * Handle reschedule and other end-of-syscall issues 818 */ 819 userret(td, &frame, sticks); 820 821 CTR4(KTR_SYSC, "syscall exit thread %p pid %d proc %s code %d", td, 822 td->td_proc->p_pid, td->td_proc->p_comm, code); 823 824 #ifdef KTRACE 825 if (KTRPOINT(td, KTR_SYSRET)) 826 ktrsysret(code, error, td->td_retval[0]); 827 #endif 828 829 /* 830 * This works because errno is findable through the 831 * register set. If we ever support an emulation where this 832 * is not the case, this code will need to be revisited. 833 */ 834 STOPEVENT(p, S_SCX, code); 835 836 PTRACESTOP_SC(p, td, S_PT_SCX); 837 838 WITNESS_WARN(WARN_PANIC, NULL, "System call %s returning", 839 (code >= 0 && code < SYS_MAXSYSCALL) ? syscallnames[code] : "???"); 840 mtx_assert(&sched_lock, MA_NOTOWNED); 841 mtx_assert(&Giant, MA_NOTOWNED); 842 }
Cache object: d497314dcb228b84fc92abe59ba61a39
[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]