Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/amd64/amd64/trap.c
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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/5.2/sys/amd64/amd64/trap.c 122940 2003-11-21 03:02:00Z peter $"); 42 43 /* 44 * AMD64 Trap and System call handling 45 */ 46 47 #include "opt_clock.h" 48 #include "opt_cpu.h" 49 #include "opt_ddb.h" 50 #include "opt_isa.h" 51 #include "opt_ktrace.h" 52 53 #include <sys/param.h> 54 #include <sys/bus.h> 55 #include <sys/systm.h> 56 #include <sys/proc.h> 57 #include <sys/pioctl.h> 58 #include <sys/ptrace.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 #include <ddb/ddb.h> 92 93 extern void trap(struct trapframe frame); 94 extern void syscall(struct trapframe frame); 95 96 static int trap_pfault(struct trapframe *, int); 97 static void trap_fatal(struct trapframe *, vm_offset_t); 98 void dblfault_handler(void); 99 100 #define MAX_TRAP_MSG 28 101 static char *trap_msg[] = { 102 "", /* 0 unused */ 103 "privileged instruction fault", /* 1 T_PRIVINFLT */ 104 "", /* 2 unused */ 105 "breakpoint instruction fault", /* 3 T_BPTFLT */ 106 "", /* 4 unused */ 107 "", /* 5 unused */ 108 "arithmetic trap", /* 6 T_ARITHTRAP */ 109 "", /* 7 unused */ 110 "", /* 8 unused */ 111 "general protection fault", /* 9 T_PROTFLT */ 112 "trace trap", /* 10 T_TRCTRAP */ 113 "", /* 11 unused */ 114 "page fault", /* 12 T_PAGEFLT */ 115 "", /* 13 unused */ 116 "alignment fault", /* 14 T_ALIGNFLT */ 117 "", /* 15 unused */ 118 "", /* 16 unused */ 119 "", /* 17 unused */ 120 "integer divide fault", /* 18 T_DIVIDE */ 121 "non-maskable interrupt trap", /* 19 T_NMI */ 122 "overflow trap", /* 20 T_OFLOW */ 123 "FPU bounds check fault", /* 21 T_BOUND */ 124 "FPU device not available", /* 22 T_DNA */ 125 "double fault", /* 23 T_DOUBLEFLT */ 126 "FPU operand fetch fault", /* 24 T_FPOPFLT */ 127 "invalid TSS fault", /* 25 T_TSSFLT */ 128 "segment not present fault", /* 26 T_SEGNPFLT */ 129 "stack fault", /* 27 T_STKFLT */ 130 "machine check trap", /* 28 T_MCHK */ 131 }; 132 133 #ifdef DDB 134 static int ddb_on_nmi = 1; 135 SYSCTL_INT(_machdep, OID_AUTO, ddb_on_nmi, CTLFLAG_RW, 136 &ddb_on_nmi, 0, "Go to DDB on NMI"); 137 #endif 138 static int panic_on_nmi = 1; 139 SYSCTL_INT(_machdep, OID_AUTO, panic_on_nmi, CTLFLAG_RW, 140 &panic_on_nmi, 0, "Panic on NMI"); 141 142 #ifdef WITNESS 143 extern char *syscallnames[]; 144 #endif 145 146 #ifdef DEVICE_POLLING 147 extern u_int32_t poll_in_trap; 148 extern int ether_poll(int count); 149 #endif /* DEVICE_POLLING */ 150 151 /* 152 * Exception, fault, and trap interface to the FreeBSD kernel. 153 * This common code is called from assembly language IDT gate entry 154 * routines that prepare a suitable stack frame, and restore this 155 * frame after the exception has been processed. 156 */ 157 158 void 159 trap(frame) 160 struct trapframe frame; 161 { 162 struct thread *td = curthread; 163 struct proc *p = td->td_proc; 164 u_int sticks = 0; 165 int i = 0, ucode = 0, type, code; 166 167 atomic_add_int(&cnt.v_trap, 1); 168 type = frame.tf_trapno; 169 170 #ifdef DDB 171 if (db_active) { 172 vm_offset_t eva; 173 eva = (type == T_PAGEFLT ? frame.tf_addr : 0); 174 trap_fatal(&frame, eva); 175 goto out; 176 } 177 #endif 178 179 if ((frame.tf_rflags & PSL_I) == 0) { 180 /* 181 * Buggy application or kernel code has disabled 182 * interrupts and then trapped. Enabling interrupts 183 * now is wrong, but it is better than running with 184 * interrupts disabled until they are accidentally 185 * enabled later. 186 */ 187 if (ISPL(frame.tf_cs) == SEL_UPL) 188 printf( 189 "pid %ld (%s): trap %d with interrupts disabled\n", 190 (long)curproc->p_pid, curproc->p_comm, type); 191 else if (type != T_BPTFLT && type != T_TRCTRAP) { 192 /* 193 * XXX not quite right, since this may be for a 194 * multiple fault in user mode. 195 */ 196 printf("kernel trap %d with interrupts disabled\n", 197 type); 198 /* 199 * We shouldn't enable interrupts while in a critical 200 * section. 201 */ 202 if (td->td_critnest == 0) 203 enable_intr(); 204 } 205 } 206 207 code = frame.tf_err; 208 if (type == T_PAGEFLT) { 209 /* 210 * If we get a page fault while in a critical section, then 211 * it is most likely a fatal kernel page fault. The kernel 212 * is already going to panic trying to get a sleep lock to 213 * do the VM lookup, so just consider it a fatal trap so the 214 * kernel can print out a useful trap message and even get 215 * to the debugger. 216 */ 217 if (td->td_critnest != 0) 218 trap_fatal(&frame, frame.tf_addr); 219 } 220 221 #ifdef DEVICE_POLLING 222 if (poll_in_trap) 223 ether_poll(poll_in_trap); 224 #endif /* DEVICE_POLLING */ 225 226 if (ISPL(frame.tf_cs) == SEL_UPL) { 227 /* user trap */ 228 229 sticks = td->td_sticks; 230 td->td_frame = &frame; 231 if (td->td_ucred != p->p_ucred) 232 cred_update_thread(td); 233 234 switch (type) { 235 case T_PRIVINFLT: /* privileged instruction fault */ 236 ucode = type; 237 i = SIGILL; 238 break; 239 240 case T_BPTFLT: /* bpt instruction fault */ 241 case T_TRCTRAP: /* trace trap */ 242 enable_intr(); 243 frame.tf_rflags &= ~PSL_T; 244 i = SIGTRAP; 245 break; 246 247 case T_ARITHTRAP: /* arithmetic trap */ 248 ucode = fputrap(); 249 if (ucode == -1) 250 goto userout; 251 i = SIGFPE; 252 break; 253 254 case T_PROTFLT: /* general protection fault */ 255 case T_STKFLT: /* stack fault */ 256 case T_SEGNPFLT: /* segment not present fault */ 257 case T_TSSFLT: /* invalid TSS fault */ 258 case T_DOUBLEFLT: /* double fault */ 259 default: 260 ucode = code + BUS_SEGM_FAULT ; 261 i = SIGBUS; 262 break; 263 264 case T_PAGEFLT: /* page fault */ 265 if (td->td_flags & TDF_SA) 266 thread_user_enter(p, td); 267 i = trap_pfault(&frame, TRUE); 268 if (i == -1) 269 goto userout; 270 if (i == 0) 271 goto user; 272 273 ucode = T_PAGEFLT; 274 break; 275 276 case T_DIVIDE: /* integer divide fault */ 277 ucode = FPE_INTDIV; 278 i = SIGFPE; 279 break; 280 281 #ifdef DEV_ISA 282 case T_NMI: 283 /* machine/parity/power fail/"kitchen sink" faults */ 284 /* XXX Giant */ 285 if (isa_nmi(code) == 0) { 286 #ifdef DDB 287 /* 288 * NMI can be hooked up to a pushbutton 289 * for debugging. 290 */ 291 if (ddb_on_nmi) { 292 printf ("NMI ... going to debugger\n"); 293 kdb_trap (type, 0, &frame); 294 } 295 #endif /* DDB */ 296 goto userout; 297 } else if (panic_on_nmi) 298 panic("NMI indicates hardware failure"); 299 break; 300 #endif /* DEV_ISA */ 301 302 case T_OFLOW: /* integer overflow fault */ 303 ucode = FPE_INTOVF; 304 i = SIGFPE; 305 break; 306 307 case T_BOUND: /* bounds check fault */ 308 ucode = FPE_FLTSUB; 309 i = SIGFPE; 310 break; 311 312 case T_DNA: 313 /* transparent fault (due to context switch "late") */ 314 if (fpudna()) 315 goto userout; 316 i = SIGFPE; 317 ucode = FPE_FPU_NP_TRAP; 318 break; 319 320 case T_FPOPFLT: /* FPU operand fetch fault */ 321 ucode = T_FPOPFLT; 322 i = SIGILL; 323 break; 324 325 case T_XMMFLT: /* SIMD floating-point exception */ 326 ucode = 0; /* XXX */ 327 i = SIGFPE; 328 break; 329 } 330 } else { 331 /* kernel trap */ 332 333 KASSERT(cold || td->td_ucred != NULL, 334 ("kernel trap doesn't have ucred")); 335 switch (type) { 336 case T_PAGEFLT: /* page fault */ 337 (void) trap_pfault(&frame, FALSE); 338 goto out; 339 340 case T_DNA: 341 /* 342 * The kernel is apparently using fpu for copying. 343 * XXX this should be fatal unless the kernel has 344 * registered such use. 345 */ 346 if (fpudna()) { 347 printf("fpudna in kernel mode!\n"); 348 goto out; 349 } 350 break; 351 352 case T_STKFLT: /* stack fault */ 353 break; 354 355 case T_PROTFLT: /* general protection fault */ 356 case T_SEGNPFLT: /* segment not present fault */ 357 if (td->td_intr_nesting_level != 0) 358 break; 359 360 /* 361 * Invalid segment selectors and out of bounds 362 * %eip's and %esp's can be set up in user mode. 363 * This causes a fault in kernel mode when the 364 * kernel tries to return to user mode. We want 365 * to get this fault so that we can fix the 366 * problem here and not have to check all the 367 * selectors and pointers when the user changes 368 * them. 369 */ 370 if (frame.tf_rip == (long)doreti_iret) { 371 frame.tf_rip = (long)doreti_iret_fault; 372 goto out; 373 } 374 if (PCPU_GET(curpcb) != NULL && 375 PCPU_GET(curpcb)->pcb_onfault != NULL) { 376 frame.tf_rip = 377 (long)PCPU_GET(curpcb)->pcb_onfault; 378 goto out; 379 } 380 break; 381 382 case T_TSSFLT: 383 /* 384 * PSL_NT can be set in user mode and isn't cleared 385 * automatically when the kernel is entered. This 386 * causes a TSS fault when the kernel attempts to 387 * `iret' because the TSS link is uninitialized. We 388 * want to get this fault so that we can fix the 389 * problem here and not every time the kernel is 390 * entered. 391 */ 392 if (frame.tf_rflags & PSL_NT) { 393 frame.tf_rflags &= ~PSL_NT; 394 goto out; 395 } 396 break; 397 398 case T_TRCTRAP: /* trace trap */ 399 /* 400 * FALLTHROUGH (TRCTRAP kernel mode, kernel address) 401 */ 402 case T_BPTFLT: 403 /* 404 * If DDB is enabled, let it handle the debugger trap. 405 * Otherwise, debugger traps "can't happen". 406 */ 407 #ifdef DDB 408 /* XXX Giant */ 409 if (kdb_trap (type, 0, &frame)) 410 goto out; 411 #endif 412 break; 413 414 #ifdef DEV_ISA 415 case T_NMI: 416 /* XXX Giant */ 417 /* machine/parity/power fail/"kitchen sink" faults */ 418 if (isa_nmi(code) == 0) { 419 #ifdef DDB 420 /* 421 * NMI can be hooked up to a pushbutton 422 * for debugging. 423 */ 424 if (ddb_on_nmi) { 425 printf ("NMI ... going to debugger\n"); 426 kdb_trap (type, 0, &frame); 427 } 428 #endif /* DDB */ 429 goto out; 430 } else if (panic_on_nmi == 0) 431 goto out; 432 /* FALLTHROUGH */ 433 #endif /* DEV_ISA */ 434 } 435 436 trap_fatal(&frame, 0); 437 goto out; 438 } 439 440 /* Translate fault for emulators (e.g. Linux) */ 441 if (*p->p_sysent->sv_transtrap) 442 i = (*p->p_sysent->sv_transtrap)(i, type); 443 444 trapsignal(td, i, ucode); 445 446 #ifdef DEBUG 447 if (type <= MAX_TRAP_MSG) { 448 uprintf("fatal process exception: %s", 449 trap_msg[type]); 450 if ((type == T_PAGEFLT) || (type == T_PROTFLT)) 451 uprintf(", fault VA = 0x%lx", frame.tf_addr); 452 uprintf("\n"); 453 } 454 #endif 455 456 user: 457 userret(td, &frame, sticks); 458 mtx_assert(&Giant, MA_NOTOWNED); 459 userout: 460 #ifdef DIAGNOSTIC 461 cred_free_thread(td); 462 #endif 463 out: 464 return; 465 } 466 467 static int 468 trap_pfault(frame, usermode) 469 struct trapframe *frame; 470 int usermode; 471 { 472 vm_offset_t va; 473 struct vmspace *vm = NULL; 474 vm_map_t map = 0; 475 int rv = 0; 476 vm_prot_t ftype; 477 struct thread *td = curthread; 478 struct proc *p = td->td_proc; 479 vm_offset_t eva = frame->tf_addr; 480 481 va = trunc_page(eva); 482 if (va >= KERNBASE) { 483 /* 484 * Don't allow user-mode faults in kernel address space. 485 */ 486 if (usermode) 487 goto nogo; 488 489 map = kernel_map; 490 } else { 491 /* 492 * This is a fault on non-kernel virtual memory. 493 * vm is initialized above to NULL. If curproc is NULL 494 * or curproc->p_vmspace is NULL the fault is fatal. 495 */ 496 if (p != NULL) 497 vm = p->p_vmspace; 498 499 if (vm == NULL) 500 goto nogo; 501 502 map = &vm->vm_map; 503 } 504 505 if (frame->tf_err & PGEX_W) 506 ftype = VM_PROT_WRITE; 507 else 508 ftype = VM_PROT_READ; 509 510 if (map != kernel_map) { 511 /* 512 * Keep swapout from messing with us during this 513 * critical time. 514 */ 515 PROC_LOCK(p); 516 ++p->p_lock; 517 PROC_UNLOCK(p); 518 519 /* Fault in the user page: */ 520 rv = vm_fault(map, va, ftype, 521 (ftype & VM_PROT_WRITE) ? VM_FAULT_DIRTY 522 : VM_FAULT_NORMAL); 523 524 PROC_LOCK(p); 525 --p->p_lock; 526 PROC_UNLOCK(p); 527 } else { 528 /* 529 * Don't have to worry about process locking or stacks in the 530 * kernel. 531 */ 532 rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL); 533 } 534 if (rv == KERN_SUCCESS) 535 return (0); 536 nogo: 537 if (!usermode) { 538 if (td->td_intr_nesting_level == 0 && 539 PCPU_GET(curpcb) != NULL && 540 PCPU_GET(curpcb)->pcb_onfault != NULL) { 541 frame->tf_rip = (long)PCPU_GET(curpcb)->pcb_onfault; 542 return (0); 543 } 544 trap_fatal(frame, eva); 545 return (-1); 546 } 547 548 return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV); 549 } 550 551 static void 552 trap_fatal(frame, eva) 553 struct trapframe *frame; 554 vm_offset_t eva; 555 { 556 int code, type, ss; 557 long esp; 558 struct soft_segment_descriptor softseg; 559 560 code = frame->tf_err; 561 type = frame->tf_trapno; 562 sdtossd(&gdt[IDXSEL(frame->tf_cs & 0xffff)], &softseg); 563 564 if (type <= MAX_TRAP_MSG) 565 printf("\n\nFatal trap %d: %s while in %s mode\n", 566 type, trap_msg[type], 567 ISPL(frame->tf_cs) == SEL_UPL ? "user" : "kernel"); 568 #ifdef SMP 569 /* two separate prints in case of a trap on an unmapped page */ 570 printf("cpuid = %d; ", PCPU_GET(cpuid)); 571 printf("apic id = %02x\n", PCPU_GET(apic_id)); 572 #endif 573 if (type == T_PAGEFLT) { 574 printf("fault virtual address = 0x%lx\n", eva); 575 printf("fault code = %s %s, %s\n", 576 code & PGEX_U ? "user" : "supervisor", 577 code & PGEX_W ? "write" : "read", 578 code & PGEX_P ? "protection violation" : "page not present"); 579 } 580 printf("instruction pointer = 0x%lx:0x%lx\n", 581 frame->tf_cs & 0xffff, frame->tf_rip); 582 if (ISPL(frame->tf_cs) == SEL_UPL) { 583 ss = frame->tf_ss & 0xffff; 584 esp = frame->tf_rsp; 585 } else { 586 ss = GSEL(GDATA_SEL, SEL_KPL); 587 esp = (long)&frame->tf_rsp; 588 } 589 printf("stack pointer = 0x%x:0x%lx\n", ss, esp); 590 printf("frame pointer = 0x%x:0x%lx\n", ss, frame->tf_rbp); 591 printf("code segment = base 0x%lx, limit 0x%lx, type 0x%x\n", 592 softseg.ssd_base, softseg.ssd_limit, softseg.ssd_type); 593 printf(" = DPL %d, pres %d, long %d, def32 %d, gran %d\n", 594 softseg.ssd_dpl, softseg.ssd_p, softseg.ssd_long, softseg.ssd_def32, 595 softseg.ssd_gran); 596 printf("processor eflags = "); 597 if (frame->tf_rflags & PSL_T) 598 printf("trace trap, "); 599 if (frame->tf_rflags & PSL_I) 600 printf("interrupt enabled, "); 601 if (frame->tf_rflags & PSL_NT) 602 printf("nested task, "); 603 if (frame->tf_rflags & PSL_RF) 604 printf("resume, "); 605 printf("IOPL = %ld\n", (frame->tf_rflags & PSL_IOPL) >> 12); 606 printf("current process = "); 607 if (curproc) { 608 printf("%lu (%s)\n", 609 (u_long)curproc->p_pid, curproc->p_comm ? 610 curproc->p_comm : ""); 611 } else { 612 printf("Idle\n"); 613 } 614 615 #ifdef KDB 616 if (kdb_trap(&psl)) 617 return; 618 #endif 619 #ifdef DDB 620 if ((debugger_on_panic || db_active) && kdb_trap(type, 0, frame)) 621 return; 622 #endif 623 printf("trap number = %d\n", type); 624 if (type <= MAX_TRAP_MSG) 625 panic("%s", trap_msg[type]); 626 else 627 panic("unknown/reserved trap"); 628 } 629 630 /* 631 * Double fault handler. Called when a fault occurs while writing 632 * a frame for a trap/exception onto the stack. This usually occurs 633 * when the stack overflows (such is the case with infinite recursion, 634 * for example). 635 */ 636 void 637 dblfault_handler() 638 { 639 printf("\nFatal double fault\n"); 640 #ifdef SMP 641 /* two separate prints in case of a trap on an unmapped page */ 642 printf("cpuid = %d; ", PCPU_GET(cpuid)); 643 printf("apic id = %02x\n", PCPU_GET(apic_id)); 644 #endif 645 panic("double fault"); 646 } 647 648 /* 649 * syscall - system call request C handler 650 * 651 * A system call is essentially treated as a trap. 652 */ 653 void 654 syscall(frame) 655 struct trapframe frame; 656 { 657 caddr_t params; 658 struct sysent *callp; 659 struct thread *td = curthread; 660 struct proc *p = td->td_proc; 661 register_t orig_tf_rflags; 662 u_int sticks; 663 int error; 664 int narg; 665 register_t args[8]; 666 register_t *argp; 667 u_int code; 668 int reg, regcnt; 669 670 /* 671 * note: PCPU_LAZY_INC() can only be used if we can afford 672 * occassional inaccuracy in the count. 673 */ 674 PCPU_LAZY_INC(cnt.v_syscall); 675 676 #ifdef DIAGNOSTIC 677 if (ISPL(frame.tf_cs) != SEL_UPL) { 678 mtx_lock(&Giant); /* try to stabilize the system XXX */ 679 panic("syscall"); 680 /* NOT REACHED */ 681 mtx_unlock(&Giant); 682 } 683 #endif 684 685 reg = 0; 686 regcnt = 6; 687 sticks = td->td_sticks; 688 td->td_frame = &frame; 689 if (td->td_ucred != p->p_ucred) 690 cred_update_thread(td); 691 if (p->p_flag & P_SA) 692 thread_user_enter(p, td); 693 params = (caddr_t)frame.tf_rsp + sizeof(register_t); 694 code = frame.tf_rax; 695 orig_tf_rflags = frame.tf_rflags; 696 697 if (p->p_sysent->sv_prepsyscall) { 698 /* 699 * The prep code is MP aware. 700 */ 701 (*p->p_sysent->sv_prepsyscall)(&frame, (int *)args, &code, ¶ms); 702 } else { 703 if (code == SYS_syscall || code == SYS___syscall) { 704 code = frame.tf_rdi; 705 reg++; 706 regcnt--; 707 } 708 } 709 710 if (p->p_sysent->sv_mask) 711 code &= p->p_sysent->sv_mask; 712 713 if (code >= p->p_sysent->sv_size) 714 callp = &p->p_sysent->sv_table[0]; 715 else 716 callp = &p->p_sysent->sv_table[code]; 717 718 narg = callp->sy_narg & SYF_ARGMASK; 719 720 /* 721 * copyin and the ktrsyscall()/ktrsysret() code is MP-aware 722 */ 723 if (narg <= regcnt) { 724 argp = &frame.tf_rdi; 725 argp += reg; 726 error = 0; 727 } else { 728 KASSERT(narg <= sizeof(args) / sizeof(args[0]), 729 ("Too many syscall arguments!")); 730 KASSERT(params != NULL, ("copyin args with no params!")); 731 argp = &frame.tf_rdi; 732 argp += reg; 733 bcopy(argp, args, sizeof(args[0]) * regcnt); 734 error = copyin(params, &args[regcnt], 735 (narg - regcnt) * sizeof(args[0])); 736 argp = &args[0]; 737 } 738 739 #ifdef KTRACE 740 if (KTRPOINT(td, KTR_SYSCALL)) 741 ktrsyscall(code, narg, argp); 742 #endif 743 744 /* 745 * Try to run the syscall without Giant if the syscall 746 * is MP safe. 747 */ 748 if ((callp->sy_narg & SYF_MPSAFE) == 0) 749 mtx_lock(&Giant); 750 751 if (error == 0) { 752 td->td_retval[0] = 0; 753 td->td_retval[1] = frame.tf_rdx; 754 755 STOPEVENT(p, S_SCE, narg); 756 757 PTRACESTOP_SC(p, td, S_PT_SCE); 758 759 error = (*callp->sy_call)(td, argp); 760 } 761 762 switch (error) { 763 case 0: 764 frame.tf_rax = td->td_retval[0]; 765 frame.tf_rdx = td->td_retval[1]; 766 frame.tf_rflags &= ~PSL_C; 767 break; 768 769 case ERESTART: 770 /* 771 * Reconstruct pc, we know that 'syscall' is 2 bytes. 772 * We have to do a full context restore so that %r10 773 * (which was holding the value of %rcx) is restored for 774 * the next iteration. 775 */ 776 frame.tf_rip -= frame.tf_err; 777 frame.tf_r10 = frame.tf_rcx; 778 td->td_pcb->pcb_flags |= PCB_FULLCTX; 779 break; 780 781 case EJUSTRETURN: 782 break; 783 784 default: 785 if (p->p_sysent->sv_errsize) { 786 if (error >= p->p_sysent->sv_errsize) 787 error = -1; /* XXX */ 788 else 789 error = p->p_sysent->sv_errtbl[error]; 790 } 791 frame.tf_rax = error; 792 frame.tf_rflags |= PSL_C; 793 break; 794 } 795 796 /* 797 * Release Giant if we previously set it. 798 */ 799 if ((callp->sy_narg & SYF_MPSAFE) == 0) 800 mtx_unlock(&Giant); 801 802 /* 803 * Traced syscall. 804 */ 805 if (orig_tf_rflags & PSL_T) { 806 frame.tf_rflags &= ~PSL_T; 807 trapsignal(td, SIGTRAP, 0); 808 } 809 810 /* 811 * Handle reschedule and other end-of-syscall issues 812 */ 813 userret(td, &frame, sticks); 814 815 #ifdef KTRACE 816 if (KTRPOINT(td, KTR_SYSRET)) 817 ktrsysret(code, error, td->td_retval[0]); 818 #endif 819 820 /* 821 * This works because errno is findable through the 822 * register set. If we ever support an emulation where this 823 * is not the case, this code will need to be revisited. 824 */ 825 STOPEVENT(p, S_SCX, code); 826 827 PTRACESTOP_SC(p, td, S_PT_SCX); 828 829 #ifdef DIAGNOSTIC 830 cred_free_thread(td); 831 #endif 832 WITNESS_WARN(WARN_PANIC, NULL, "System call %s returning", 833 (code >= 0 && code < SYS_MAXSYSCALL) ? syscallnames[code] : "???"); 834 mtx_assert(&sched_lock, MA_NOTOWNED); 835 mtx_assert(&Giant, MA_NOTOWNED); 836 }
Cache object: 1d7f76662bfcdb8d6af29c72c7591c37
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