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/6.2/sys/amd64/amd64/trap.c 152905 2005-11-28 20:03:15Z jhb $"); 42 43 /* 44 * AMD64 Trap and System call handling 45 */ 46 47 #include "opt_clock.h" 48 #include "opt_cpu.h" 49 #include "opt_hwpmc_hooks.h" 50 #include "opt_isa.h" 51 #include "opt_kdb.h" 52 #include "opt_ktrace.h" 53 54 #include <sys/param.h> 55 #include <sys/bus.h> 56 #include <sys/systm.h> 57 #include <sys/proc.h> 58 #include <sys/pioctl.h> 59 #include <sys/ptrace.h> 60 #include <sys/kdb.h> 61 #include <sys/kernel.h> 62 #include <sys/ktr.h> 63 #include <sys/lock.h> 64 #include <sys/mutex.h> 65 #include <sys/resourcevar.h> 66 #include <sys/signalvar.h> 67 #include <sys/syscall.h> 68 #include <sys/sysctl.h> 69 #include <sys/sysent.h> 70 #include <sys/uio.h> 71 #include <sys/vmmeter.h> 72 #ifdef KTRACE 73 #include <sys/ktrace.h> 74 #endif 75 #ifdef HWPMC_HOOKS 76 #include <sys/pmckern.h> 77 #endif 78 79 #include <vm/vm.h> 80 #include <vm/vm_param.h> 81 #include <vm/pmap.h> 82 #include <vm/vm_kern.h> 83 #include <vm/vm_map.h> 84 #include <vm/vm_page.h> 85 #include <vm/vm_extern.h> 86 87 #include <machine/cpu.h> 88 #include <machine/intr_machdep.h> 89 #include <machine/md_var.h> 90 #include <machine/pcb.h> 91 #ifdef SMP 92 #include <machine/smp.h> 93 #endif 94 #include <machine/tss.h> 95 96 extern void trap(struct trapframe frame); 97 extern void syscall(struct trapframe frame); 98 99 static int trap_pfault(struct trapframe *, int); 100 static void trap_fatal(struct trapframe *, vm_offset_t); 101 void dblfault_handler(void); 102 103 #define MAX_TRAP_MSG 30 104 static char *trap_msg[] = { 105 "", /* 0 unused */ 106 "privileged instruction fault", /* 1 T_PRIVINFLT */ 107 "", /* 2 unused */ 108 "breakpoint instruction fault", /* 3 T_BPTFLT */ 109 "", /* 4 unused */ 110 "", /* 5 unused */ 111 "arithmetic trap", /* 6 T_ARITHTRAP */ 112 "", /* 7 unused */ 113 "", /* 8 unused */ 114 "general protection fault", /* 9 T_PROTFLT */ 115 "trace trap", /* 10 T_TRCTRAP */ 116 "", /* 11 unused */ 117 "page fault", /* 12 T_PAGEFLT */ 118 "", /* 13 unused */ 119 "alignment fault", /* 14 T_ALIGNFLT */ 120 "", /* 15 unused */ 121 "", /* 16 unused */ 122 "", /* 17 unused */ 123 "integer divide fault", /* 18 T_DIVIDE */ 124 "non-maskable interrupt trap", /* 19 T_NMI */ 125 "overflow trap", /* 20 T_OFLOW */ 126 "FPU bounds check fault", /* 21 T_BOUND */ 127 "FPU device not available", /* 22 T_DNA */ 128 "double fault", /* 23 T_DOUBLEFLT */ 129 "FPU operand fetch fault", /* 24 T_FPOPFLT */ 130 "invalid TSS fault", /* 25 T_TSSFLT */ 131 "segment not present fault", /* 26 T_SEGNPFLT */ 132 "stack fault", /* 27 T_STKFLT */ 133 "machine check trap", /* 28 T_MCHK */ 134 "SIMD floating-point exception", /* 29 T_XMMFLT */ 135 "reserved (unknown) fault", /* 30 T_RESERVED */ 136 }; 137 138 #ifdef KDB 139 static int kdb_on_nmi = 1; 140 SYSCTL_INT(_machdep, OID_AUTO, kdb_on_nmi, CTLFLAG_RW, 141 &kdb_on_nmi, 0, "Go to KDB on NMI"); 142 #endif 143 static int panic_on_nmi = 1; 144 SYSCTL_INT(_machdep, OID_AUTO, panic_on_nmi, CTLFLAG_RW, 145 &panic_on_nmi, 0, "Panic on NMI"); 146 147 #ifdef WITNESS 148 extern char *syscallnames[]; 149 #endif 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 PCPU_LAZY_INC(cnt.v_trap); 168 type = frame.tf_trapno; 169 170 #ifdef KDB_STOP_NMI 171 /* Handler for NMI IPIs used for debugging */ 172 if (type == T_NMI) { 173 if (ipi_nmi_handler() == 0) 174 goto out; 175 } 176 #endif /* KDB_STOP_NMI */ 177 178 #ifdef KDB 179 if (kdb_active) { 180 kdb_reenter(); 181 goto out; 182 } 183 #endif 184 185 #ifdef HWPMC_HOOKS 186 /* 187 * CPU PMCs interrupt using an NMI. If the PMC module is 188 * active, pass the 'rip' value to the PMC module's interrupt 189 * handler. A return value of '1' from the handler means that 190 * the NMI was handled by it and we can return immediately. 191 */ 192 if (type == T_NMI && pmc_intr && 193 (*pmc_intr)(PCPU_GET(cpuid), (uintptr_t) frame.tf_rip, 194 TRAPF_USERMODE(&frame))) 195 goto out; 196 #endif 197 198 if ((frame.tf_rflags & PSL_I) == 0) { 199 /* 200 * Buggy application or kernel code has disabled 201 * interrupts and then trapped. Enabling interrupts 202 * now is wrong, but it is better than running with 203 * interrupts disabled until they are accidentally 204 * enabled later. 205 */ 206 if (ISPL(frame.tf_cs) == SEL_UPL) 207 printf( 208 "pid %ld (%s): trap %d with interrupts disabled\n", 209 (long)curproc->p_pid, curproc->p_comm, type); 210 else if (type != T_NMI && type != T_BPTFLT && 211 type != T_TRCTRAP) { 212 /* 213 * XXX not quite right, since this may be for a 214 * multiple fault in user mode. 215 */ 216 printf("kernel trap %d with interrupts disabled\n", 217 type); 218 /* 219 * We shouldn't enable interrupts while in a critical 220 * section. 221 */ 222 if (td->td_critnest == 0) 223 enable_intr(); 224 } 225 } 226 227 code = frame.tf_err; 228 if (type == T_PAGEFLT) { 229 /* 230 * If we get a page fault while in a critical section, then 231 * it is most likely a fatal kernel page fault. The kernel 232 * is already going to panic trying to get a sleep lock to 233 * do the VM lookup, so just consider it a fatal trap so the 234 * kernel can print out a useful trap message and even get 235 * to the debugger. 236 */ 237 if (td->td_critnest != 0) 238 trap_fatal(&frame, frame.tf_addr); 239 } 240 241 if (ISPL(frame.tf_cs) == SEL_UPL) { 242 /* user trap */ 243 244 sticks = td->td_sticks; 245 td->td_frame = &frame; 246 if (td->td_ucred != p->p_ucred) 247 cred_update_thread(td); 248 249 switch (type) { 250 case T_PRIVINFLT: /* privileged instruction fault */ 251 ucode = type; 252 i = SIGILL; 253 break; 254 255 case T_BPTFLT: /* bpt instruction fault */ 256 case T_TRCTRAP: /* trace trap */ 257 enable_intr(); 258 frame.tf_rflags &= ~PSL_T; 259 i = SIGTRAP; 260 break; 261 262 case T_ARITHTRAP: /* arithmetic trap */ 263 ucode = fputrap(); 264 if (ucode == -1) 265 goto userout; 266 i = SIGFPE; 267 break; 268 269 case T_PROTFLT: /* general protection fault */ 270 case T_STKFLT: /* stack fault */ 271 case T_SEGNPFLT: /* segment not present fault */ 272 case T_TSSFLT: /* invalid TSS fault */ 273 case T_DOUBLEFLT: /* double fault */ 274 default: 275 ucode = code + BUS_SEGM_FAULT ; 276 i = SIGBUS; 277 break; 278 279 case T_PAGEFLT: /* page fault */ 280 if (td->td_pflags & TDP_SA) 281 thread_user_enter(td); 282 i = trap_pfault(&frame, TRUE); 283 if (i == -1) 284 goto userout; 285 if (i == 0) 286 goto user; 287 288 ucode = T_PAGEFLT; 289 break; 290 291 case T_DIVIDE: /* integer divide fault */ 292 ucode = FPE_INTDIV; 293 i = SIGFPE; 294 break; 295 296 #ifdef DEV_ISA 297 case T_NMI: 298 /* machine/parity/power fail/"kitchen sink" faults */ 299 /* XXX Giant */ 300 if (isa_nmi(code) == 0) { 301 #ifdef KDB 302 /* 303 * NMI can be hooked up to a pushbutton 304 * for debugging. 305 */ 306 if (kdb_on_nmi) { 307 printf ("NMI ... going to debugger\n"); 308 kdb_trap(type, 0, &frame); 309 } 310 #endif /* KDB */ 311 goto userout; 312 } else if (panic_on_nmi) 313 panic("NMI indicates hardware failure"); 314 break; 315 #endif /* DEV_ISA */ 316 317 case T_OFLOW: /* integer overflow fault */ 318 ucode = FPE_INTOVF; 319 i = SIGFPE; 320 break; 321 322 case T_BOUND: /* bounds check fault */ 323 ucode = FPE_FLTSUB; 324 i = SIGFPE; 325 break; 326 327 case T_DNA: 328 /* transparent fault (due to context switch "late") */ 329 if (fpudna()) 330 goto userout; 331 i = SIGFPE; 332 ucode = FPE_FPU_NP_TRAP; 333 break; 334 335 case T_FPOPFLT: /* FPU operand fetch fault */ 336 ucode = T_FPOPFLT; 337 i = SIGILL; 338 break; 339 340 case T_XMMFLT: /* SIMD floating-point exception */ 341 ucode = 0; /* XXX */ 342 i = SIGFPE; 343 break; 344 } 345 } else { 346 /* kernel trap */ 347 348 KASSERT(cold || td->td_ucred != NULL, 349 ("kernel trap doesn't have ucred")); 350 switch (type) { 351 case T_PAGEFLT: /* page fault */ 352 (void) trap_pfault(&frame, FALSE); 353 goto out; 354 355 case T_DNA: 356 /* 357 * The kernel is apparently using fpu for copying. 358 * XXX this should be fatal unless the kernel has 359 * registered such use. 360 */ 361 if (fpudna()) { 362 printf("fpudna in kernel mode!\n"); 363 goto out; 364 } 365 break; 366 367 case T_STKFLT: /* stack fault */ 368 break; 369 370 case T_PROTFLT: /* general protection fault */ 371 case T_SEGNPFLT: /* segment not present fault */ 372 if (td->td_intr_nesting_level != 0) 373 break; 374 375 /* 376 * Invalid segment selectors and out of bounds 377 * %rip's and %rsp's can be set up in user mode. 378 * This causes a fault in kernel mode when the 379 * kernel tries to return to user mode. We want 380 * to get this fault so that we can fix the 381 * problem here and not have to check all the 382 * selectors and pointers when the user changes 383 * them. 384 */ 385 if (frame.tf_rip == (long)doreti_iret) { 386 frame.tf_rip = (long)doreti_iret_fault; 387 goto out; 388 } 389 if (PCPU_GET(curpcb)->pcb_onfault != NULL) { 390 frame.tf_rip = 391 (long)PCPU_GET(curpcb)->pcb_onfault; 392 goto out; 393 } 394 break; 395 396 case T_TSSFLT: 397 /* 398 * PSL_NT can be set in user mode and isn't cleared 399 * automatically when the kernel is entered. This 400 * causes a TSS fault when the kernel attempts to 401 * `iret' because the TSS link is uninitialized. We 402 * want to get this fault so that we can fix the 403 * problem here and not every time the kernel is 404 * entered. 405 */ 406 if (frame.tf_rflags & PSL_NT) { 407 frame.tf_rflags &= ~PSL_NT; 408 goto out; 409 } 410 break; 411 412 case T_TRCTRAP: /* trace trap */ 413 /* 414 * Ignore debug register trace traps due to 415 * accesses in the user's address space, which 416 * can happen under several conditions such as 417 * if a user sets a watchpoint on a buffer and 418 * then passes that buffer to a system call. 419 * We still want to get TRCTRAPS for addresses 420 * in kernel space because that is useful when 421 * debugging the kernel. 422 */ 423 if (user_dbreg_trap()) { 424 /* 425 * Reset breakpoint bits because the 426 * processor doesn't 427 */ 428 /* XXX check upper bits here */ 429 load_dr6(rdr6() & 0xfffffff0); 430 goto out; 431 } 432 /* 433 * FALLTHROUGH (TRCTRAP kernel mode, kernel address) 434 */ 435 case T_BPTFLT: 436 /* 437 * If KDB is enabled, let it handle the debugger trap. 438 * Otherwise, debugger traps "can't happen". 439 */ 440 #ifdef KDB 441 /* XXX Giant */ 442 if (kdb_trap(type, 0, &frame)) 443 goto out; 444 #endif 445 break; 446 447 #ifdef DEV_ISA 448 case T_NMI: 449 /* XXX Giant */ 450 /* machine/parity/power fail/"kitchen sink" faults */ 451 if (isa_nmi(code) == 0) { 452 #ifdef KDB 453 /* 454 * NMI can be hooked up to a pushbutton 455 * for debugging. 456 */ 457 if (kdb_on_nmi) { 458 printf ("NMI ... going to debugger\n"); 459 kdb_trap(type, 0, &frame); 460 } 461 #endif /* KDB */ 462 goto out; 463 } else if (panic_on_nmi == 0) 464 goto out; 465 /* FALLTHROUGH */ 466 #endif /* DEV_ISA */ 467 } 468 469 trap_fatal(&frame, 0); 470 goto out; 471 } 472 473 /* Translate fault for emulators (e.g. Linux) */ 474 if (*p->p_sysent->sv_transtrap) 475 i = (*p->p_sysent->sv_transtrap)(i, type); 476 477 trapsignal(td, i, ucode); 478 479 #ifdef DEBUG 480 if (type <= MAX_TRAP_MSG) { 481 uprintf("fatal process exception: %s", 482 trap_msg[type]); 483 if ((type == T_PAGEFLT) || (type == T_PROTFLT)) 484 uprintf(", fault VA = 0x%lx", frame.tf_addr); 485 uprintf("\n"); 486 } 487 #endif 488 489 user: 490 userret(td, &frame, sticks); 491 mtx_assert(&Giant, MA_NOTOWNED); 492 userout: 493 out: 494 return; 495 } 496 497 static int 498 trap_pfault(frame, usermode) 499 struct trapframe *frame; 500 int usermode; 501 { 502 vm_offset_t va; 503 struct vmspace *vm = NULL; 504 vm_map_t map = 0; 505 int rv = 0; 506 vm_prot_t ftype; 507 struct thread *td = curthread; 508 struct proc *p = td->td_proc; 509 vm_offset_t eva = frame->tf_addr; 510 511 va = trunc_page(eva); 512 if (va >= KERNBASE) { 513 /* 514 * Don't allow user-mode faults in kernel address space. 515 */ 516 if (usermode) 517 goto nogo; 518 519 map = kernel_map; 520 } else { 521 /* 522 * This is a fault on non-kernel virtual memory. 523 * vm is initialized above to NULL. If curproc is NULL 524 * or curproc->p_vmspace is NULL the fault is fatal. 525 */ 526 if (p != NULL) 527 vm = p->p_vmspace; 528 529 if (vm == NULL) 530 goto nogo; 531 532 map = &vm->vm_map; 533 } 534 535 if (frame->tf_err & PGEX_W) 536 ftype = VM_PROT_WRITE; 537 else 538 ftype = VM_PROT_READ; 539 540 if (map != kernel_map) { 541 /* 542 * Keep swapout from messing with us during this 543 * critical time. 544 */ 545 PROC_LOCK(p); 546 ++p->p_lock; 547 PROC_UNLOCK(p); 548 549 /* Fault in the user page: */ 550 rv = vm_fault(map, va, ftype, 551 (ftype & VM_PROT_WRITE) ? VM_FAULT_DIRTY 552 : VM_FAULT_NORMAL); 553 554 PROC_LOCK(p); 555 --p->p_lock; 556 PROC_UNLOCK(p); 557 } else { 558 /* 559 * Don't have to worry about process locking or stacks in the 560 * kernel. 561 */ 562 rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL); 563 } 564 if (rv == KERN_SUCCESS) 565 return (0); 566 nogo: 567 if (!usermode) { 568 if (td->td_intr_nesting_level == 0 && 569 PCPU_GET(curpcb)->pcb_onfault != NULL) { 570 frame->tf_rip = (long)PCPU_GET(curpcb)->pcb_onfault; 571 return (0); 572 } 573 trap_fatal(frame, eva); 574 return (-1); 575 } 576 577 return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV); 578 } 579 580 static void 581 trap_fatal(frame, eva) 582 struct trapframe *frame; 583 vm_offset_t eva; 584 { 585 int code, type, ss; 586 long esp; 587 struct soft_segment_descriptor softseg; 588 char *msg; 589 590 code = frame->tf_err; 591 type = frame->tf_trapno; 592 sdtossd(&gdt[IDXSEL(frame->tf_cs & 0xffff)], &softseg); 593 594 if (type <= MAX_TRAP_MSG) 595 msg = trap_msg[type]; 596 else 597 msg = "UNKNOWN"; 598 printf("\n\nFatal trap %d: %s while in %s mode\n", type, msg, 599 ISPL(frame->tf_cs) == SEL_UPL ? "user" : "kernel"); 600 #ifdef SMP 601 /* two separate prints in case of a trap on an unmapped page */ 602 printf("cpuid = %d; ", PCPU_GET(cpuid)); 603 printf("apic id = %02x\n", PCPU_GET(apic_id)); 604 #endif 605 if (type == T_PAGEFLT) { 606 printf("fault virtual address = 0x%lx\n", eva); 607 printf("fault code = %s %s, %s\n", 608 code & PGEX_U ? "user" : "supervisor", 609 code & PGEX_W ? "write" : "read", 610 code & PGEX_P ? "protection violation" : "page not present"); 611 } 612 printf("instruction pointer = 0x%lx:0x%lx\n", 613 frame->tf_cs & 0xffff, frame->tf_rip); 614 if (ISPL(frame->tf_cs) == SEL_UPL) { 615 ss = frame->tf_ss & 0xffff; 616 esp = frame->tf_rsp; 617 } else { 618 ss = GSEL(GDATA_SEL, SEL_KPL); 619 esp = (long)&frame->tf_rsp; 620 } 621 printf("stack pointer = 0x%x:0x%lx\n", ss, esp); 622 printf("frame pointer = 0x%x:0x%lx\n", ss, frame->tf_rbp); 623 printf("code segment = base 0x%lx, limit 0x%lx, type 0x%x\n", 624 softseg.ssd_base, softseg.ssd_limit, softseg.ssd_type); 625 printf(" = DPL %d, pres %d, long %d, def32 %d, gran %d\n", 626 softseg.ssd_dpl, softseg.ssd_p, softseg.ssd_long, softseg.ssd_def32, 627 softseg.ssd_gran); 628 printf("processor eflags = "); 629 if (frame->tf_rflags & PSL_T) 630 printf("trace trap, "); 631 if (frame->tf_rflags & PSL_I) 632 printf("interrupt enabled, "); 633 if (frame->tf_rflags & PSL_NT) 634 printf("nested task, "); 635 if (frame->tf_rflags & PSL_RF) 636 printf("resume, "); 637 printf("IOPL = %ld\n", (frame->tf_rflags & PSL_IOPL) >> 12); 638 printf("current process = "); 639 if (curproc) { 640 printf("%lu (%s)\n", 641 (u_long)curproc->p_pid, curproc->p_comm ? 642 curproc->p_comm : ""); 643 } else { 644 printf("Idle\n"); 645 } 646 647 #ifdef KDB 648 if (debugger_on_panic || kdb_active) { 649 register_t rflags; 650 rflags = intr_disable(); 651 if (kdb_trap(type, 0, frame)) { 652 intr_restore(rflags); 653 return; 654 } 655 intr_restore(rflags); 656 } 657 #endif 658 printf("trap number = %d\n", type); 659 if (type <= MAX_TRAP_MSG) 660 panic("%s", trap_msg[type]); 661 else 662 panic("unknown/reserved trap"); 663 } 664 665 /* 666 * Double fault handler. Called when a fault occurs while writing 667 * a frame for a trap/exception onto the stack. This usually occurs 668 * when the stack overflows (such is the case with infinite recursion, 669 * for example). 670 */ 671 void 672 dblfault_handler() 673 { 674 printf("\nFatal double fault\n"); 675 #ifdef SMP 676 /* two separate prints in case of a trap on an unmapped page */ 677 printf("cpuid = %d; ", PCPU_GET(cpuid)); 678 printf("apic id = %02x\n", PCPU_GET(apic_id)); 679 #endif 680 panic("double fault"); 681 } 682 683 /* 684 * syscall - system call request C handler 685 * 686 * A system call is essentially treated as a trap. 687 */ 688 void 689 syscall(frame) 690 struct trapframe frame; 691 { 692 caddr_t params; 693 struct sysent *callp; 694 struct thread *td = curthread; 695 struct proc *p = td->td_proc; 696 register_t orig_tf_rflags; 697 u_int sticks; 698 int error; 699 int narg; 700 register_t args[8]; 701 register_t *argp; 702 u_int code; 703 int reg, regcnt; 704 705 /* 706 * note: PCPU_LAZY_INC() can only be used if we can afford 707 * occassional inaccuracy in the count. 708 */ 709 PCPU_LAZY_INC(cnt.v_syscall); 710 711 #ifdef DIAGNOSTIC 712 if (ISPL(frame.tf_cs) != SEL_UPL) { 713 mtx_lock(&Giant); /* try to stabilize the system XXX */ 714 panic("syscall"); 715 /* NOT REACHED */ 716 mtx_unlock(&Giant); 717 } 718 #endif 719 720 reg = 0; 721 regcnt = 6; 722 sticks = td->td_sticks; 723 td->td_frame = &frame; 724 if (td->td_ucred != p->p_ucred) 725 cred_update_thread(td); 726 if (p->p_flag & P_SA) 727 thread_user_enter(td); 728 params = (caddr_t)frame.tf_rsp + sizeof(register_t); 729 code = frame.tf_rax; 730 orig_tf_rflags = frame.tf_rflags; 731 732 if (p->p_sysent->sv_prepsyscall) { 733 /* 734 * The prep code is MP aware. 735 */ 736 (*p->p_sysent->sv_prepsyscall)(&frame, (int *)args, &code, ¶ms); 737 } else { 738 if (code == SYS_syscall || code == SYS___syscall) { 739 code = frame.tf_rdi; 740 reg++; 741 regcnt--; 742 } 743 } 744 745 if (p->p_sysent->sv_mask) 746 code &= p->p_sysent->sv_mask; 747 748 if (code >= p->p_sysent->sv_size) 749 callp = &p->p_sysent->sv_table[0]; 750 else 751 callp = &p->p_sysent->sv_table[code]; 752 753 narg = callp->sy_narg & SYF_ARGMASK; 754 755 /* 756 * copyin and the ktrsyscall()/ktrsysret() code is MP-aware 757 */ 758 KASSERT(narg <= sizeof(args) / sizeof(args[0]), 759 ("Too many syscall arguments!")); 760 error = 0; 761 argp = &frame.tf_rdi; 762 argp += reg; 763 bcopy(argp, args, sizeof(args[0]) * regcnt); 764 if (narg > regcnt) { 765 KASSERT(params != NULL, ("copyin args with no params!")); 766 error = copyin(params, &args[regcnt], 767 (narg - regcnt) * sizeof(args[0])); 768 } 769 argp = &args[0]; 770 771 #ifdef KTRACE 772 if (KTRPOINT(td, KTR_SYSCALL)) 773 ktrsyscall(code, narg, argp); 774 #endif 775 776 CTR4(KTR_SYSC, "syscall enter thread %p pid %d proc %s code %d", td, 777 td->td_proc->p_pid, td->td_proc->p_comm, code); 778 779 if (error == 0) { 780 td->td_retval[0] = 0; 781 td->td_retval[1] = frame.tf_rdx; 782 783 STOPEVENT(p, S_SCE, narg); 784 785 PTRACESTOP_SC(p, td, S_PT_SCE); 786 787 if ((callp->sy_narg & SYF_MPSAFE) == 0) { 788 mtx_lock(&Giant); 789 error = (*callp->sy_call)(td, argp); 790 mtx_unlock(&Giant); 791 } else 792 error = (*callp->sy_call)(td, argp); 793 } 794 795 switch (error) { 796 case 0: 797 frame.tf_rax = td->td_retval[0]; 798 frame.tf_rdx = td->td_retval[1]; 799 frame.tf_rflags &= ~PSL_C; 800 break; 801 802 case ERESTART: 803 /* 804 * Reconstruct pc, we know that 'syscall' is 2 bytes. 805 * We have to do a full context restore so that %r10 806 * (which was holding the value of %rcx) is restored for 807 * the next iteration. 808 */ 809 frame.tf_rip -= frame.tf_err; 810 frame.tf_r10 = frame.tf_rcx; 811 td->td_pcb->pcb_flags |= PCB_FULLCTX; 812 break; 813 814 case EJUSTRETURN: 815 break; 816 817 default: 818 if (p->p_sysent->sv_errsize) { 819 if (error >= p->p_sysent->sv_errsize) 820 error = -1; /* XXX */ 821 else 822 error = p->p_sysent->sv_errtbl[error]; 823 } 824 frame.tf_rax = error; 825 frame.tf_rflags |= PSL_C; 826 break; 827 } 828 829 /* 830 * Traced syscall. 831 */ 832 if (orig_tf_rflags & PSL_T) { 833 frame.tf_rflags &= ~PSL_T; 834 trapsignal(td, SIGTRAP, 0); 835 } 836 837 /* 838 * Handle reschedule and other end-of-syscall issues 839 */ 840 userret(td, &frame, sticks); 841 842 CTR4(KTR_SYSC, "syscall exit thread %p pid %d proc %s code %d", td, 843 td->td_proc->p_pid, td->td_proc->p_comm, code); 844 845 #ifdef KTRACE 846 if (KTRPOINT(td, KTR_SYSRET)) 847 ktrsysret(code, error, td->td_retval[0]); 848 #endif 849 850 /* 851 * This works because errno is findable through the 852 * register set. If we ever support an emulation where this 853 * is not the case, this code will need to be revisited. 854 */ 855 STOPEVENT(p, S_SCX, code); 856 857 PTRACESTOP_SC(p, td, S_PT_SCX); 858 859 WITNESS_WARN(WARN_PANIC, NULL, "System call %s returning", 860 (code >= 0 && code < SYS_MAXSYSCALL) ? syscallnames[code] : "???"); 861 mtx_assert(&sched_lock, MA_NOTOWNED); 862 mtx_assert(&Giant, MA_NOTOWNED); 863 }
Cache object: 449eba4511a8bfcca18fca3fcb749a1f
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