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("$FreeBSD$"); 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 30 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 "SIMD floating-point exception", /* 29 T_XMMFLT */ 130 "reserved (unknown) fault", /* 30 T_RESERVED */ 131 }; 132 133 #ifdef KDB 134 static int kdb_on_nmi = 1; 135 SYSCTL_INT(_machdep, OID_AUTO, kdb_on_nmi, CTLFLAG_RW, 136 &kdb_on_nmi, 0, "Go to KDB 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 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 if ((frame.tf_rflags & PSL_I) == 0) { 186 /* 187 * Buggy application or kernel code has disabled 188 * interrupts and then trapped. Enabling interrupts 189 * now is wrong, but it is better than running with 190 * interrupts disabled until they are accidentally 191 * enabled later. 192 */ 193 if (ISPL(frame.tf_cs) == SEL_UPL) 194 printf( 195 "pid %ld (%s): trap %d with interrupts disabled\n", 196 (long)curproc->p_pid, curproc->p_comm, type); 197 else if (type != T_BPTFLT && type != T_TRCTRAP) { 198 /* 199 * XXX not quite right, since this may be for a 200 * multiple fault in user mode. 201 */ 202 printf("kernel trap %d with interrupts disabled\n", 203 type); 204 /* 205 * We shouldn't enable interrupts while in a critical 206 * section. 207 */ 208 if (td->td_critnest == 0) 209 enable_intr(); 210 } 211 } 212 213 code = frame.tf_err; 214 if (type == T_PAGEFLT) { 215 /* 216 * If we get a page fault while in a critical section, then 217 * it is most likely a fatal kernel page fault. The kernel 218 * is already going to panic trying to get a sleep lock to 219 * do the VM lookup, so just consider it a fatal trap so the 220 * kernel can print out a useful trap message and even get 221 * to the debugger. 222 */ 223 if (td->td_critnest != 0) 224 trap_fatal(&frame, frame.tf_addr); 225 } 226 227 #ifdef DEVICE_POLLING 228 if (poll_in_trap) 229 ether_poll(poll_in_trap); 230 #endif /* DEVICE_POLLING */ 231 232 if (ISPL(frame.tf_cs) == SEL_UPL) { 233 /* user trap */ 234 235 sticks = td->td_sticks; 236 td->td_frame = &frame; 237 if (td->td_ucred != p->p_ucred) 238 cred_update_thread(td); 239 240 switch (type) { 241 case T_PRIVINFLT: /* privileged instruction fault */ 242 ucode = type; 243 i = SIGILL; 244 break; 245 246 case T_BPTFLT: /* bpt instruction fault */ 247 case T_TRCTRAP: /* trace trap */ 248 enable_intr(); 249 frame.tf_rflags &= ~PSL_T; 250 i = SIGTRAP; 251 break; 252 253 case T_ARITHTRAP: /* arithmetic trap */ 254 ucode = fputrap(); 255 if (ucode == -1) 256 goto userout; 257 i = SIGFPE; 258 break; 259 260 case T_PROTFLT: /* general protection fault */ 261 case T_STKFLT: /* stack fault */ 262 case T_SEGNPFLT: /* segment not present fault */ 263 case T_TSSFLT: /* invalid TSS fault */ 264 case T_DOUBLEFLT: /* double fault */ 265 default: 266 ucode = code + BUS_SEGM_FAULT ; 267 i = SIGBUS; 268 break; 269 270 case T_PAGEFLT: /* page fault */ 271 if (td->td_pflags & TDP_SA) 272 thread_user_enter(td); 273 i = trap_pfault(&frame, TRUE); 274 if (i == -1) 275 goto userout; 276 if (i == 0) 277 goto user; 278 279 ucode = T_PAGEFLT; 280 break; 281 282 case T_DIVIDE: /* integer divide fault */ 283 ucode = FPE_INTDIV; 284 i = SIGFPE; 285 break; 286 287 #ifdef DEV_ISA 288 case T_NMI: 289 /* machine/parity/power fail/"kitchen sink" faults */ 290 /* XXX Giant */ 291 if (isa_nmi(code) == 0) { 292 #ifdef KDB 293 /* 294 * NMI can be hooked up to a pushbutton 295 * for debugging. 296 */ 297 if (kdb_on_nmi) { 298 printf ("NMI ... going to debugger\n"); 299 kdb_trap(type, 0, &frame); 300 } 301 #endif /* KDB */ 302 goto userout; 303 } else if (panic_on_nmi) 304 panic("NMI indicates hardware failure"); 305 break; 306 #endif /* DEV_ISA */ 307 308 case T_OFLOW: /* integer overflow fault */ 309 ucode = FPE_INTOVF; 310 i = SIGFPE; 311 break; 312 313 case T_BOUND: /* bounds check fault */ 314 ucode = FPE_FLTSUB; 315 i = SIGFPE; 316 break; 317 318 case T_DNA: 319 /* transparent fault (due to context switch "late") */ 320 if (fpudna()) 321 goto userout; 322 i = SIGFPE; 323 ucode = FPE_FPU_NP_TRAP; 324 break; 325 326 case T_FPOPFLT: /* FPU operand fetch fault */ 327 ucode = T_FPOPFLT; 328 i = SIGILL; 329 break; 330 331 case T_XMMFLT: /* SIMD floating-point exception */ 332 ucode = 0; /* XXX */ 333 i = SIGFPE; 334 break; 335 } 336 } else { 337 /* kernel trap */ 338 339 KASSERT(cold || td->td_ucred != NULL, 340 ("kernel trap doesn't have ucred")); 341 switch (type) { 342 case T_PAGEFLT: /* page fault */ 343 (void) trap_pfault(&frame, FALSE); 344 goto out; 345 346 case T_DNA: 347 /* 348 * The kernel is apparently using fpu for copying. 349 * XXX this should be fatal unless the kernel has 350 * registered such use. 351 */ 352 if (fpudna()) { 353 printf("fpudna in kernel mode!\n"); 354 goto out; 355 } 356 break; 357 358 case T_STKFLT: /* stack fault */ 359 break; 360 361 case T_PROTFLT: /* general protection fault */ 362 case T_SEGNPFLT: /* segment not present fault */ 363 if (td->td_intr_nesting_level != 0) 364 break; 365 366 /* 367 * Invalid segment selectors and out of bounds 368 * %eip's and %esp's can be set up in user mode. 369 * This causes a fault in kernel mode when the 370 * kernel tries to return to user mode. We want 371 * to get this fault so that we can fix the 372 * problem here and not have to check all the 373 * selectors and pointers when the user changes 374 * them. 375 */ 376 if (frame.tf_rip == (long)doreti_iret) { 377 frame.tf_rip = (long)doreti_iret_fault; 378 goto out; 379 } 380 if (PCPU_GET(curpcb)->pcb_onfault != NULL) { 381 frame.tf_rip = 382 (long)PCPU_GET(curpcb)->pcb_onfault; 383 goto out; 384 } 385 break; 386 387 case T_TSSFLT: 388 /* 389 * PSL_NT can be set in user mode and isn't cleared 390 * automatically when the kernel is entered. This 391 * causes a TSS fault when the kernel attempts to 392 * `iret' because the TSS link is uninitialized. We 393 * want to get this fault so that we can fix the 394 * problem here and not every time the kernel is 395 * entered. 396 */ 397 if (frame.tf_rflags & PSL_NT) { 398 frame.tf_rflags &= ~PSL_NT; 399 goto out; 400 } 401 break; 402 403 case T_TRCTRAP: /* trace trap */ 404 /* 405 * Ignore debug register trace traps due to 406 * accesses in the user's address space, which 407 * can happen under several conditions such as 408 * if a user sets a watchpoint on a buffer and 409 * then passes that buffer to a system call. 410 * We still want to get TRCTRAPS for addresses 411 * in kernel space because that is useful when 412 * debugging the kernel. 413 */ 414 if (user_dbreg_trap()) { 415 /* 416 * Reset breakpoint bits because the 417 * processor doesn't 418 */ 419 /* XXX check upper bits here */ 420 load_dr6(rdr6() & 0xfffffff0); 421 goto out; 422 } 423 /* 424 * FALLTHROUGH (TRCTRAP kernel mode, kernel address) 425 */ 426 case T_BPTFLT: 427 /* 428 * If KDB is enabled, let it handle the debugger trap. 429 * Otherwise, debugger traps "can't happen". 430 */ 431 #ifdef KDB 432 /* XXX Giant */ 433 if (kdb_trap(type, 0, &frame)) 434 goto out; 435 #endif 436 break; 437 438 #ifdef DEV_ISA 439 case T_NMI: 440 /* XXX Giant */ 441 /* machine/parity/power fail/"kitchen sink" faults */ 442 if (isa_nmi(code) == 0) { 443 #ifdef KDB 444 /* 445 * NMI can be hooked up to a pushbutton 446 * for debugging. 447 */ 448 if (kdb_on_nmi) { 449 printf ("NMI ... going to debugger\n"); 450 kdb_trap(type, 0, &frame); 451 } 452 #endif /* KDB */ 453 goto out; 454 } else if (panic_on_nmi == 0) 455 goto out; 456 /* FALLTHROUGH */ 457 #endif /* DEV_ISA */ 458 } 459 460 trap_fatal(&frame, 0); 461 goto out; 462 } 463 464 /* Translate fault for emulators (e.g. Linux) */ 465 if (*p->p_sysent->sv_transtrap) 466 i = (*p->p_sysent->sv_transtrap)(i, type); 467 468 trapsignal(td, i, ucode); 469 470 #ifdef DEBUG 471 if (type <= MAX_TRAP_MSG) { 472 uprintf("fatal process exception: %s", 473 trap_msg[type]); 474 if ((type == T_PAGEFLT) || (type == T_PROTFLT)) 475 uprintf(", fault VA = 0x%lx", frame.tf_addr); 476 uprintf("\n"); 477 } 478 #endif 479 480 user: 481 userret(td, &frame, sticks); 482 mtx_assert(&Giant, MA_NOTOWNED); 483 userout: 484 out: 485 return; 486 } 487 488 static int 489 trap_pfault(frame, usermode) 490 struct trapframe *frame; 491 int usermode; 492 { 493 vm_offset_t va; 494 struct vmspace *vm = NULL; 495 vm_map_t map = 0; 496 int rv = 0; 497 vm_prot_t ftype; 498 struct thread *td = curthread; 499 struct proc *p = td->td_proc; 500 vm_offset_t eva = frame->tf_addr; 501 502 va = trunc_page(eva); 503 if (va >= KERNBASE) { 504 /* 505 * Don't allow user-mode faults in kernel address space. 506 */ 507 if (usermode) 508 goto nogo; 509 510 map = kernel_map; 511 } else { 512 /* 513 * This is a fault on non-kernel virtual memory. 514 * vm is initialized above to NULL. If curproc is NULL 515 * or curproc->p_vmspace is NULL the fault is fatal. 516 */ 517 if (p != NULL) 518 vm = p->p_vmspace; 519 520 if (vm == NULL) 521 goto nogo; 522 523 map = &vm->vm_map; 524 } 525 526 if (frame->tf_err & PGEX_W) 527 ftype = VM_PROT_WRITE; 528 else 529 ftype = VM_PROT_READ; 530 531 if (map != kernel_map) { 532 /* 533 * Keep swapout from messing with us during this 534 * critical time. 535 */ 536 PROC_LOCK(p); 537 ++p->p_lock; 538 PROC_UNLOCK(p); 539 540 /* Fault in the user page: */ 541 rv = vm_fault(map, va, ftype, 542 (ftype & VM_PROT_WRITE) ? VM_FAULT_DIRTY 543 : VM_FAULT_NORMAL); 544 545 PROC_LOCK(p); 546 --p->p_lock; 547 PROC_UNLOCK(p); 548 } else { 549 /* 550 * Don't have to worry about process locking or stacks in the 551 * kernel. 552 */ 553 rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL); 554 } 555 if (rv == KERN_SUCCESS) 556 return (0); 557 nogo: 558 if (!usermode) { 559 if (td->td_intr_nesting_level == 0 && 560 PCPU_GET(curpcb)->pcb_onfault != NULL) { 561 frame->tf_rip = (long)PCPU_GET(curpcb)->pcb_onfault; 562 return (0); 563 } 564 trap_fatal(frame, eva); 565 return (-1); 566 } 567 568 return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV); 569 } 570 571 static void 572 trap_fatal(frame, eva) 573 struct trapframe *frame; 574 vm_offset_t eva; 575 { 576 int code, type, ss; 577 long esp; 578 struct soft_segment_descriptor softseg; 579 char *msg; 580 581 code = frame->tf_err; 582 type = frame->tf_trapno; 583 sdtossd(&gdt[IDXSEL(frame->tf_cs & 0xffff)], &softseg); 584 585 if (type <= MAX_TRAP_MSG) 586 msg = trap_msg[type]; 587 else 588 msg = "UNKNOWN"; 589 printf("\n\nFatal trap %d: %s while in %s mode\n", type, msg, 590 ISPL(frame->tf_cs) == SEL_UPL ? "user" : "kernel"); 591 #ifdef SMP 592 /* two separate prints in case of a trap on an unmapped page */ 593 printf("cpuid = %d; ", PCPU_GET(cpuid)); 594 printf("apic id = %02x\n", PCPU_GET(apic_id)); 595 #endif 596 if (type == T_PAGEFLT) { 597 printf("fault virtual address = 0x%lx\n", eva); 598 printf("fault code = %s %s, %s\n", 599 code & PGEX_U ? "user" : "supervisor", 600 code & PGEX_W ? "write" : "read", 601 code & PGEX_P ? "protection violation" : "page not present"); 602 } 603 printf("instruction pointer = 0x%lx:0x%lx\n", 604 frame->tf_cs & 0xffff, frame->tf_rip); 605 if (ISPL(frame->tf_cs) == SEL_UPL) { 606 ss = frame->tf_ss & 0xffff; 607 esp = frame->tf_rsp; 608 } else { 609 ss = GSEL(GDATA_SEL, SEL_KPL); 610 esp = (long)&frame->tf_rsp; 611 } 612 printf("stack pointer = 0x%x:0x%lx\n", ss, esp); 613 printf("frame pointer = 0x%x:0x%lx\n", ss, frame->tf_rbp); 614 printf("code segment = base 0x%lx, limit 0x%lx, type 0x%x\n", 615 softseg.ssd_base, softseg.ssd_limit, softseg.ssd_type); 616 printf(" = DPL %d, pres %d, long %d, def32 %d, gran %d\n", 617 softseg.ssd_dpl, softseg.ssd_p, softseg.ssd_long, softseg.ssd_def32, 618 softseg.ssd_gran); 619 printf("processor eflags = "); 620 if (frame->tf_rflags & PSL_T) 621 printf("trace trap, "); 622 if (frame->tf_rflags & PSL_I) 623 printf("interrupt enabled, "); 624 if (frame->tf_rflags & PSL_NT) 625 printf("nested task, "); 626 if (frame->tf_rflags & PSL_RF) 627 printf("resume, "); 628 printf("IOPL = %ld\n", (frame->tf_rflags & PSL_IOPL) >> 12); 629 printf("current process = "); 630 if (curproc) { 631 printf("%lu (%s)\n", 632 (u_long)curproc->p_pid, curproc->p_comm ? 633 curproc->p_comm : ""); 634 } else { 635 printf("Idle\n"); 636 } 637 638 #ifdef KDB 639 if (kdb_trap(type, 0, frame)) 640 return; 641 #endif 642 printf("trap number = %d\n", type); 643 if (type <= MAX_TRAP_MSG) 644 panic("%s", trap_msg[type]); 645 else 646 panic("unknown/reserved trap"); 647 } 648 649 /* 650 * Double fault handler. Called when a fault occurs while writing 651 * a frame for a trap/exception onto the stack. This usually occurs 652 * when the stack overflows (such is the case with infinite recursion, 653 * for example). 654 */ 655 void 656 dblfault_handler() 657 { 658 printf("\nFatal double fault\n"); 659 #ifdef SMP 660 /* two separate prints in case of a trap on an unmapped page */ 661 printf("cpuid = %d; ", PCPU_GET(cpuid)); 662 printf("apic id = %02x\n", PCPU_GET(apic_id)); 663 #endif 664 panic("double fault"); 665 } 666 667 /* 668 * syscall - system call request C handler 669 * 670 * A system call is essentially treated as a trap. 671 */ 672 void 673 syscall(frame) 674 struct trapframe frame; 675 { 676 caddr_t params; 677 struct sysent *callp; 678 struct thread *td = curthread; 679 struct proc *p = td->td_proc; 680 register_t orig_tf_rflags; 681 u_int sticks; 682 int error; 683 int narg; 684 register_t args[8]; 685 register_t *argp; 686 u_int code; 687 int reg, regcnt; 688 689 /* 690 * note: PCPU_LAZY_INC() can only be used if we can afford 691 * occassional inaccuracy in the count. 692 */ 693 PCPU_LAZY_INC(cnt.v_syscall); 694 695 #ifdef DIAGNOSTIC 696 if (ISPL(frame.tf_cs) != SEL_UPL) { 697 mtx_lock(&Giant); /* try to stabilize the system XXX */ 698 panic("syscall"); 699 /* NOT REACHED */ 700 mtx_unlock(&Giant); 701 } 702 #endif 703 704 reg = 0; 705 regcnt = 6; 706 sticks = td->td_sticks; 707 td->td_frame = &frame; 708 if (td->td_ucred != p->p_ucred) 709 cred_update_thread(td); 710 if (p->p_flag & P_SA) 711 thread_user_enter(td); 712 params = (caddr_t)frame.tf_rsp + sizeof(register_t); 713 code = frame.tf_rax; 714 orig_tf_rflags = frame.tf_rflags; 715 716 if (p->p_sysent->sv_prepsyscall) { 717 /* 718 * The prep code is MP aware. 719 */ 720 (*p->p_sysent->sv_prepsyscall)(&frame, (int *)args, &code, ¶ms); 721 } else { 722 if (code == SYS_syscall || code == SYS___syscall) { 723 code = frame.tf_rdi; 724 reg++; 725 regcnt--; 726 } 727 } 728 729 if (p->p_sysent->sv_mask) 730 code &= p->p_sysent->sv_mask; 731 732 if (code >= p->p_sysent->sv_size) 733 callp = &p->p_sysent->sv_table[0]; 734 else 735 callp = &p->p_sysent->sv_table[code]; 736 737 narg = callp->sy_narg & SYF_ARGMASK; 738 739 /* 740 * copyin and the ktrsyscall()/ktrsysret() code is MP-aware 741 */ 742 KASSERT(narg <= sizeof(args) / sizeof(args[0]), 743 ("Too many syscall arguments!")); 744 error = 0; 745 argp = &frame.tf_rdi; 746 argp += reg; 747 bcopy(argp, args, sizeof(args[0]) * regcnt); 748 if (narg > regcnt) { 749 KASSERT(params != NULL, ("copyin args with no params!")); 750 error = copyin(params, &args[regcnt], 751 (narg - regcnt) * sizeof(args[0])); 752 } 753 argp = &args[0]; 754 755 #ifdef KTRACE 756 if (KTRPOINT(td, KTR_SYSCALL)) 757 ktrsyscall(code, narg, argp); 758 #endif 759 760 CTR4(KTR_SYSC, "syscall enter thread %p pid %d proc %s code %d", td, 761 td->td_proc->p_pid, td->td_proc->p_comm, code); 762 763 if (error == 0) { 764 td->td_retval[0] = 0; 765 td->td_retval[1] = frame.tf_rdx; 766 767 STOPEVENT(p, S_SCE, narg); 768 769 PTRACESTOP_SC(p, td, S_PT_SCE); 770 771 if ((callp->sy_narg & SYF_MPSAFE) == 0) { 772 mtx_lock(&Giant); 773 error = (*callp->sy_call)(td, argp); 774 mtx_unlock(&Giant); 775 } else 776 error = (*callp->sy_call)(td, argp); 777 } 778 779 switch (error) { 780 case 0: 781 frame.tf_rax = td->td_retval[0]; 782 frame.tf_rdx = td->td_retval[1]; 783 frame.tf_rflags &= ~PSL_C; 784 break; 785 786 case ERESTART: 787 /* 788 * Reconstruct pc, we know that 'syscall' is 2 bytes. 789 * We have to do a full context restore so that %r10 790 * (which was holding the value of %rcx) is restored for 791 * the next iteration. 792 */ 793 frame.tf_rip -= frame.tf_err; 794 frame.tf_r10 = frame.tf_rcx; 795 td->td_pcb->pcb_flags |= PCB_FULLCTX; 796 break; 797 798 case EJUSTRETURN: 799 break; 800 801 default: 802 if (p->p_sysent->sv_errsize) { 803 if (error >= p->p_sysent->sv_errsize) 804 error = -1; /* XXX */ 805 else 806 error = p->p_sysent->sv_errtbl[error]; 807 } 808 frame.tf_rax = error; 809 frame.tf_rflags |= PSL_C; 810 break; 811 } 812 813 /* 814 * Traced syscall. 815 */ 816 if (orig_tf_rflags & PSL_T) { 817 frame.tf_rflags &= ~PSL_T; 818 trapsignal(td, SIGTRAP, 0); 819 } 820 821 /* 822 * Handle reschedule and other end-of-syscall issues 823 */ 824 userret(td, &frame, sticks); 825 826 CTR4(KTR_SYSC, "syscall exit thread %p pid %d proc %s code %d", td, 827 td->td_proc->p_pid, td->td_proc->p_comm, code); 828 829 #ifdef KTRACE 830 if (KTRPOINT(td, KTR_SYSRET)) 831 ktrsysret(code, error, td->td_retval[0]); 832 #endif 833 834 /* 835 * This works because errno is findable through the 836 * register set. If we ever support an emulation where this 837 * is not the case, this code will need to be revisited. 838 */ 839 STOPEVENT(p, S_SCX, code); 840 841 PTRACESTOP_SC(p, td, S_PT_SCX); 842 843 WITNESS_WARN(WARN_PANIC, NULL, "System call %s returning", 844 (code >= 0 && code < SYS_MAXSYSCALL) ? syscallnames[code] : "???"); 845 mtx_assert(&sched_lock, MA_NOTOWNED); 846 mtx_assert(&Giant, MA_NOTOWNED); 847 }
Cache object: 8eff4f1116982cfd711ed8352e9cca7c
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