Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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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/6.0/sys/amd64/amd64/trap.c 151061 2005-10-07 14:00:06Z glebius $"); 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 28 104 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 }; 135 136 #ifdef KDB 137 static int kdb_on_nmi = 1; 138 SYSCTL_INT(_machdep, OID_AUTO, kdb_on_nmi, CTLFLAG_RW, 139 &kdb_on_nmi, 0, "Go to KDB on NMI"); 140 #endif 141 static int panic_on_nmi = 1; 142 SYSCTL_INT(_machdep, OID_AUTO, panic_on_nmi, CTLFLAG_RW, 143 &panic_on_nmi, 0, "Panic on NMI"); 144 145 #ifdef WITNESS 146 extern char *syscallnames[]; 147 #endif 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 PCPU_LAZY_INC(cnt.v_trap); 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 #ifdef HWPMC_HOOKS 184 /* 185 * CPU PMCs interrupt using an NMI. If the PMC module is 186 * active, pass the 'rip' value to the PMC module's interrupt 187 * handler. A return value of '1' from the handler means that 188 * the NMI was handled by it and we can return immediately. 189 */ 190 if (type == T_NMI && pmc_intr && 191 (*pmc_intr)(PCPU_GET(cpuid), (uintptr_t) frame.tf_rip, 192 TRAPF_USERMODE(&frame))) 193 goto out; 194 #endif 195 196 if ((frame.tf_rflags & PSL_I) == 0) { 197 /* 198 * Buggy application or kernel code has disabled 199 * interrupts and then trapped. Enabling interrupts 200 * now is wrong, but it is better than running with 201 * interrupts disabled until they are accidentally 202 * enabled later. 203 */ 204 if (ISPL(frame.tf_cs) == SEL_UPL) 205 printf( 206 "pid %ld (%s): trap %d with interrupts disabled\n", 207 (long)curproc->p_pid, curproc->p_comm, type); 208 else if (type != T_NMI && type != T_BPTFLT && 209 type != T_TRCTRAP) { 210 /* 211 * XXX not quite right, since this may be for a 212 * multiple fault in user mode. 213 */ 214 printf("kernel trap %d with interrupts disabled\n", 215 type); 216 /* 217 * We shouldn't enable interrupts while in a critical 218 * section. 219 */ 220 if (td->td_critnest == 0) 221 enable_intr(); 222 } 223 } 224 225 code = frame.tf_err; 226 if (type == T_PAGEFLT) { 227 /* 228 * If we get a page fault while in a critical section, then 229 * it is most likely a fatal kernel page fault. The kernel 230 * is already going to panic trying to get a sleep lock to 231 * do the VM lookup, so just consider it a fatal trap so the 232 * kernel can print out a useful trap message and even get 233 * to the debugger. 234 */ 235 if (td->td_critnest != 0) 236 trap_fatal(&frame, frame.tf_addr); 237 } 238 239 if (ISPL(frame.tf_cs) == SEL_UPL) { 240 /* user trap */ 241 242 sticks = td->td_sticks; 243 td->td_frame = &frame; 244 if (td->td_ucred != p->p_ucred) 245 cred_update_thread(td); 246 247 switch (type) { 248 case T_PRIVINFLT: /* privileged instruction fault */ 249 ucode = type; 250 i = SIGILL; 251 break; 252 253 case T_BPTFLT: /* bpt instruction fault */ 254 case T_TRCTRAP: /* trace trap */ 255 enable_intr(); 256 frame.tf_rflags &= ~PSL_T; 257 i = SIGTRAP; 258 break; 259 260 case T_ARITHTRAP: /* arithmetic trap */ 261 ucode = fputrap(); 262 if (ucode == -1) 263 goto userout; 264 i = SIGFPE; 265 break; 266 267 case T_PROTFLT: /* general protection fault */ 268 case T_STKFLT: /* stack fault */ 269 case T_SEGNPFLT: /* segment not present fault */ 270 case T_TSSFLT: /* invalid TSS fault */ 271 case T_DOUBLEFLT: /* double fault */ 272 default: 273 ucode = code + BUS_SEGM_FAULT ; 274 i = SIGBUS; 275 break; 276 277 case T_PAGEFLT: /* page fault */ 278 if (td->td_pflags & TDP_SA) 279 thread_user_enter(td); 280 i = trap_pfault(&frame, TRUE); 281 if (i == -1) 282 goto userout; 283 if (i == 0) 284 goto user; 285 286 ucode = T_PAGEFLT; 287 break; 288 289 case T_DIVIDE: /* integer divide fault */ 290 ucode = FPE_INTDIV; 291 i = SIGFPE; 292 break; 293 294 #ifdef DEV_ISA 295 case T_NMI: 296 /* machine/parity/power fail/"kitchen sink" faults */ 297 /* XXX Giant */ 298 if (isa_nmi(code) == 0) { 299 #ifdef KDB 300 /* 301 * NMI can be hooked up to a pushbutton 302 * for debugging. 303 */ 304 if (kdb_on_nmi) { 305 printf ("NMI ... going to debugger\n"); 306 kdb_trap(type, 0, &frame); 307 } 308 #endif /* KDB */ 309 goto userout; 310 } else if (panic_on_nmi) 311 panic("NMI indicates hardware failure"); 312 break; 313 #endif /* DEV_ISA */ 314 315 case T_OFLOW: /* integer overflow fault */ 316 ucode = FPE_INTOVF; 317 i = SIGFPE; 318 break; 319 320 case T_BOUND: /* bounds check fault */ 321 ucode = FPE_FLTSUB; 322 i = SIGFPE; 323 break; 324 325 case T_DNA: 326 /* transparent fault (due to context switch "late") */ 327 if (fpudna()) 328 goto userout; 329 i = SIGFPE; 330 ucode = FPE_FPU_NP_TRAP; 331 break; 332 333 case T_FPOPFLT: /* FPU operand fetch fault */ 334 ucode = T_FPOPFLT; 335 i = SIGILL; 336 break; 337 338 case T_XMMFLT: /* SIMD floating-point exception */ 339 ucode = 0; /* XXX */ 340 i = SIGFPE; 341 break; 342 } 343 } else { 344 /* kernel trap */ 345 346 KASSERT(cold || td->td_ucred != NULL, 347 ("kernel trap doesn't have ucred")); 348 switch (type) { 349 case T_PAGEFLT: /* page fault */ 350 (void) trap_pfault(&frame, FALSE); 351 goto out; 352 353 case T_DNA: 354 /* 355 * The kernel is apparently using fpu for copying. 356 * XXX this should be fatal unless the kernel has 357 * registered such use. 358 */ 359 if (fpudna()) { 360 printf("fpudna in kernel mode!\n"); 361 goto out; 362 } 363 break; 364 365 case T_STKFLT: /* stack fault */ 366 break; 367 368 case T_PROTFLT: /* general protection fault */ 369 case T_SEGNPFLT: /* segment not present fault */ 370 if (td->td_intr_nesting_level != 0) 371 break; 372 373 /* 374 * Invalid segment selectors and out of bounds 375 * %rip's and %rsp's can be set up in user mode. 376 * This causes a fault in kernel mode when the 377 * kernel tries to return to user mode. We want 378 * to get this fault so that we can fix the 379 * problem here and not have to check all the 380 * selectors and pointers when the user changes 381 * them. 382 */ 383 if (frame.tf_rip == (long)doreti_iret) { 384 frame.tf_rip = (long)doreti_iret_fault; 385 goto out; 386 } 387 if (PCPU_GET(curpcb)->pcb_onfault != NULL) { 388 frame.tf_rip = 389 (long)PCPU_GET(curpcb)->pcb_onfault; 390 goto out; 391 } 392 break; 393 394 case T_TSSFLT: 395 /* 396 * PSL_NT can be set in user mode and isn't cleared 397 * automatically when the kernel is entered. This 398 * causes a TSS fault when the kernel attempts to 399 * `iret' because the TSS link is uninitialized. We 400 * want to get this fault so that we can fix the 401 * problem here and not every time the kernel is 402 * entered. 403 */ 404 if (frame.tf_rflags & PSL_NT) { 405 frame.tf_rflags &= ~PSL_NT; 406 goto out; 407 } 408 break; 409 410 case T_TRCTRAP: /* trace trap */ 411 /* 412 * Ignore debug register trace traps due to 413 * accesses in the user's address space, which 414 * can happen under several conditions such as 415 * if a user sets a watchpoint on a buffer and 416 * then passes that buffer to a system call. 417 * We still want to get TRCTRAPS for addresses 418 * in kernel space because that is useful when 419 * debugging the kernel. 420 */ 421 if (user_dbreg_trap()) { 422 /* 423 * Reset breakpoint bits because the 424 * processor doesn't 425 */ 426 /* XXX check upper bits here */ 427 load_dr6(rdr6() & 0xfffffff0); 428 goto out; 429 } 430 /* 431 * FALLTHROUGH (TRCTRAP kernel mode, kernel address) 432 */ 433 case T_BPTFLT: 434 /* 435 * If KDB is enabled, let it handle the debugger trap. 436 * Otherwise, debugger traps "can't happen". 437 */ 438 #ifdef KDB 439 /* XXX Giant */ 440 if (kdb_trap(type, 0, &frame)) 441 goto out; 442 #endif 443 break; 444 445 #ifdef DEV_ISA 446 case T_NMI: 447 /* XXX Giant */ 448 /* machine/parity/power fail/"kitchen sink" faults */ 449 if (isa_nmi(code) == 0) { 450 #ifdef KDB 451 /* 452 * NMI can be hooked up to a pushbutton 453 * for debugging. 454 */ 455 if (kdb_on_nmi) { 456 printf ("NMI ... going to debugger\n"); 457 kdb_trap(type, 0, &frame); 458 } 459 #endif /* KDB */ 460 goto out; 461 } else if (panic_on_nmi == 0) 462 goto out; 463 /* FALLTHROUGH */ 464 #endif /* DEV_ISA */ 465 } 466 467 trap_fatal(&frame, 0); 468 goto out; 469 } 470 471 /* Translate fault for emulators (e.g. Linux) */ 472 if (*p->p_sysent->sv_transtrap) 473 i = (*p->p_sysent->sv_transtrap)(i, type); 474 475 trapsignal(td, i, ucode); 476 477 #ifdef DEBUG 478 if (type <= MAX_TRAP_MSG) { 479 uprintf("fatal process exception: %s", 480 trap_msg[type]); 481 if ((type == T_PAGEFLT) || (type == T_PROTFLT)) 482 uprintf(", fault VA = 0x%lx", frame.tf_addr); 483 uprintf("\n"); 484 } 485 #endif 486 487 user: 488 userret(td, &frame, sticks); 489 mtx_assert(&Giant, MA_NOTOWNED); 490 userout: 491 out: 492 return; 493 } 494 495 static int 496 trap_pfault(frame, usermode) 497 struct trapframe *frame; 498 int usermode; 499 { 500 vm_offset_t va; 501 struct vmspace *vm = NULL; 502 vm_map_t map = 0; 503 int rv = 0; 504 vm_prot_t ftype; 505 struct thread *td = curthread; 506 struct proc *p = td->td_proc; 507 vm_offset_t eva = frame->tf_addr; 508 509 va = trunc_page(eva); 510 if (va >= KERNBASE) { 511 /* 512 * Don't allow user-mode faults in kernel address space. 513 */ 514 if (usermode) 515 goto nogo; 516 517 map = kernel_map; 518 } else { 519 /* 520 * This is a fault on non-kernel virtual memory. 521 * vm is initialized above to NULL. If curproc is NULL 522 * or curproc->p_vmspace is NULL the fault is fatal. 523 */ 524 if (p != NULL) 525 vm = p->p_vmspace; 526 527 if (vm == NULL) 528 goto nogo; 529 530 map = &vm->vm_map; 531 } 532 533 if (frame->tf_err & PGEX_W) 534 ftype = VM_PROT_WRITE; 535 else 536 ftype = VM_PROT_READ; 537 538 if (map != kernel_map) { 539 /* 540 * Keep swapout from messing with us during this 541 * critical time. 542 */ 543 PROC_LOCK(p); 544 ++p->p_lock; 545 PROC_UNLOCK(p); 546 547 /* Fault in the user page: */ 548 rv = vm_fault(map, va, ftype, 549 (ftype & VM_PROT_WRITE) ? VM_FAULT_DIRTY 550 : VM_FAULT_NORMAL); 551 552 PROC_LOCK(p); 553 --p->p_lock; 554 PROC_UNLOCK(p); 555 } else { 556 /* 557 * Don't have to worry about process locking or stacks in the 558 * kernel. 559 */ 560 rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL); 561 } 562 if (rv == KERN_SUCCESS) 563 return (0); 564 nogo: 565 if (!usermode) { 566 if (td->td_intr_nesting_level == 0 && 567 PCPU_GET(curpcb)->pcb_onfault != NULL) { 568 frame->tf_rip = (long)PCPU_GET(curpcb)->pcb_onfault; 569 return (0); 570 } 571 trap_fatal(frame, eva); 572 return (-1); 573 } 574 575 return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV); 576 } 577 578 static void 579 trap_fatal(frame, eva) 580 struct trapframe *frame; 581 vm_offset_t eva; 582 { 583 int code, type, ss; 584 long esp; 585 struct soft_segment_descriptor softseg; 586 587 code = frame->tf_err; 588 type = frame->tf_trapno; 589 sdtossd(&gdt[IDXSEL(frame->tf_cs & 0xffff)], &softseg); 590 591 if (type <= MAX_TRAP_MSG) 592 printf("\n\nFatal trap %d: %s while in %s mode\n", 593 type, trap_msg[type], 594 ISPL(frame->tf_cs) == SEL_UPL ? "user" : "kernel"); 595 #ifdef SMP 596 /* two separate prints in case of a trap on an unmapped page */ 597 printf("cpuid = %d; ", PCPU_GET(cpuid)); 598 printf("apic id = %02x\n", PCPU_GET(apic_id)); 599 #endif 600 if (type == T_PAGEFLT) { 601 printf("fault virtual address = 0x%lx\n", eva); 602 printf("fault code = %s %s, %s\n", 603 code & PGEX_U ? "user" : "supervisor", 604 code & PGEX_W ? "write" : "read", 605 code & PGEX_P ? "protection violation" : "page not present"); 606 } 607 printf("instruction pointer = 0x%lx:0x%lx\n", 608 frame->tf_cs & 0xffff, frame->tf_rip); 609 if (ISPL(frame->tf_cs) == SEL_UPL) { 610 ss = frame->tf_ss & 0xffff; 611 esp = frame->tf_rsp; 612 } else { 613 ss = GSEL(GDATA_SEL, SEL_KPL); 614 esp = (long)&frame->tf_rsp; 615 } 616 printf("stack pointer = 0x%x:0x%lx\n", ss, esp); 617 printf("frame pointer = 0x%x:0x%lx\n", ss, frame->tf_rbp); 618 printf("code segment = base 0x%lx, limit 0x%lx, type 0x%x\n", 619 softseg.ssd_base, softseg.ssd_limit, softseg.ssd_type); 620 printf(" = DPL %d, pres %d, long %d, def32 %d, gran %d\n", 621 softseg.ssd_dpl, softseg.ssd_p, softseg.ssd_long, softseg.ssd_def32, 622 softseg.ssd_gran); 623 printf("processor eflags = "); 624 if (frame->tf_rflags & PSL_T) 625 printf("trace trap, "); 626 if (frame->tf_rflags & PSL_I) 627 printf("interrupt enabled, "); 628 if (frame->tf_rflags & PSL_NT) 629 printf("nested task, "); 630 if (frame->tf_rflags & PSL_RF) 631 printf("resume, "); 632 printf("IOPL = %ld\n", (frame->tf_rflags & PSL_IOPL) >> 12); 633 printf("current process = "); 634 if (curproc) { 635 printf("%lu (%s)\n", 636 (u_long)curproc->p_pid, curproc->p_comm ? 637 curproc->p_comm : ""); 638 } else { 639 printf("Idle\n"); 640 } 641 642 #ifdef KDB 643 if (debugger_on_panic || kdb_active) { 644 register_t rflags; 645 rflags = intr_disable(); 646 if (kdb_trap(type, 0, frame)) { 647 intr_restore(rflags); 648 return; 649 } 650 intr_restore(rflags); 651 } 652 #endif 653 printf("trap number = %d\n", type); 654 if (type <= MAX_TRAP_MSG) 655 panic("%s", trap_msg[type]); 656 else 657 panic("unknown/reserved trap"); 658 } 659 660 /* 661 * Double fault handler. Called when a fault occurs while writing 662 * a frame for a trap/exception onto the stack. This usually occurs 663 * when the stack overflows (such is the case with infinite recursion, 664 * for example). 665 */ 666 void 667 dblfault_handler() 668 { 669 printf("\nFatal double fault\n"); 670 #ifdef SMP 671 /* two separate prints in case of a trap on an unmapped page */ 672 printf("cpuid = %d; ", PCPU_GET(cpuid)); 673 printf("apic id = %02x\n", PCPU_GET(apic_id)); 674 #endif 675 panic("double fault"); 676 } 677 678 /* 679 * syscall - system call request C handler 680 * 681 * A system call is essentially treated as a trap. 682 */ 683 void 684 syscall(frame) 685 struct trapframe frame; 686 { 687 caddr_t params; 688 struct sysent *callp; 689 struct thread *td = curthread; 690 struct proc *p = td->td_proc; 691 register_t orig_tf_rflags; 692 u_int sticks; 693 int error; 694 int narg; 695 register_t args[8]; 696 register_t *argp; 697 u_int code; 698 int reg, regcnt; 699 700 /* 701 * note: PCPU_LAZY_INC() can only be used if we can afford 702 * occassional inaccuracy in the count. 703 */ 704 PCPU_LAZY_INC(cnt.v_syscall); 705 706 #ifdef DIAGNOSTIC 707 if (ISPL(frame.tf_cs) != SEL_UPL) { 708 mtx_lock(&Giant); /* try to stabilize the system XXX */ 709 panic("syscall"); 710 /* NOT REACHED */ 711 mtx_unlock(&Giant); 712 } 713 #endif 714 715 reg = 0; 716 regcnt = 6; 717 sticks = td->td_sticks; 718 td->td_frame = &frame; 719 if (td->td_ucred != p->p_ucred) 720 cred_update_thread(td); 721 if (p->p_flag & P_SA) 722 thread_user_enter(td); 723 params = (caddr_t)frame.tf_rsp + sizeof(register_t); 724 code = frame.tf_rax; 725 orig_tf_rflags = frame.tf_rflags; 726 727 if (p->p_sysent->sv_prepsyscall) { 728 /* 729 * The prep code is MP aware. 730 */ 731 (*p->p_sysent->sv_prepsyscall)(&frame, (int *)args, &code, ¶ms); 732 } else { 733 if (code == SYS_syscall || code == SYS___syscall) { 734 code = frame.tf_rdi; 735 reg++; 736 regcnt--; 737 } 738 } 739 740 if (p->p_sysent->sv_mask) 741 code &= p->p_sysent->sv_mask; 742 743 if (code >= p->p_sysent->sv_size) 744 callp = &p->p_sysent->sv_table[0]; 745 else 746 callp = &p->p_sysent->sv_table[code]; 747 748 narg = callp->sy_narg & SYF_ARGMASK; 749 750 /* 751 * copyin and the ktrsyscall()/ktrsysret() code is MP-aware 752 */ 753 KASSERT(narg <= sizeof(args) / sizeof(args[0]), 754 ("Too many syscall arguments!")); 755 error = 0; 756 argp = &frame.tf_rdi; 757 argp += reg; 758 bcopy(argp, args, sizeof(args[0]) * regcnt); 759 if (narg > regcnt) { 760 KASSERT(params != NULL, ("copyin args with no params!")); 761 error = copyin(params, &args[regcnt], 762 (narg - regcnt) * sizeof(args[0])); 763 } 764 argp = &args[0]; 765 766 #ifdef KTRACE 767 if (KTRPOINT(td, KTR_SYSCALL)) 768 ktrsyscall(code, narg, argp); 769 #endif 770 771 CTR4(KTR_SYSC, "syscall enter thread %p pid %d proc %s code %d", td, 772 td->td_proc->p_pid, td->td_proc->p_comm, code); 773 774 if (error == 0) { 775 td->td_retval[0] = 0; 776 td->td_retval[1] = frame.tf_rdx; 777 778 STOPEVENT(p, S_SCE, narg); 779 780 PTRACESTOP_SC(p, td, S_PT_SCE); 781 782 if ((callp->sy_narg & SYF_MPSAFE) == 0) { 783 mtx_lock(&Giant); 784 error = (*callp->sy_call)(td, argp); 785 mtx_unlock(&Giant); 786 } else 787 error = (*callp->sy_call)(td, argp); 788 } 789 790 switch (error) { 791 case 0: 792 frame.tf_rax = td->td_retval[0]; 793 frame.tf_rdx = td->td_retval[1]; 794 frame.tf_rflags &= ~PSL_C; 795 break; 796 797 case ERESTART: 798 /* 799 * Reconstruct pc, we know that 'syscall' is 2 bytes. 800 * We have to do a full context restore so that %r10 801 * (which was holding the value of %rcx) is restored for 802 * the next iteration. 803 */ 804 frame.tf_rip -= frame.tf_err; 805 frame.tf_r10 = frame.tf_rcx; 806 td->td_pcb->pcb_flags |= PCB_FULLCTX; 807 break; 808 809 case EJUSTRETURN: 810 break; 811 812 default: 813 if (p->p_sysent->sv_errsize) { 814 if (error >= p->p_sysent->sv_errsize) 815 error = -1; /* XXX */ 816 else 817 error = p->p_sysent->sv_errtbl[error]; 818 } 819 frame.tf_rax = error; 820 frame.tf_rflags |= PSL_C; 821 break; 822 } 823 824 /* 825 * Traced syscall. 826 */ 827 if (orig_tf_rflags & PSL_T) { 828 frame.tf_rflags &= ~PSL_T; 829 trapsignal(td, SIGTRAP, 0); 830 } 831 832 /* 833 * Handle reschedule and other end-of-syscall issues 834 */ 835 userret(td, &frame, sticks); 836 837 CTR4(KTR_SYSC, "syscall exit thread %p pid %d proc %s code %d", td, 838 td->td_proc->p_pid, td->td_proc->p_comm, code); 839 840 #ifdef KTRACE 841 if (KTRPOINT(td, KTR_SYSRET)) 842 ktrsysret(code, error, td->td_retval[0]); 843 #endif 844 845 /* 846 * This works because errno is findable through the 847 * register set. If we ever support an emulation where this 848 * is not the case, this code will need to be revisited. 849 */ 850 STOPEVENT(p, S_SCX, code); 851 852 PTRACESTOP_SC(p, td, S_PT_SCX); 853 854 WITNESS_WARN(WARN_PANIC, NULL, "System call %s returning", 855 (code >= 0 && code < SYS_MAXSYSCALL) ? syscallnames[code] : "???"); 856 mtx_assert(&sched_lock, MA_NOTOWNED); 857 mtx_assert(&Giant, MA_NOTOWNED); 858 }
Cache object: 5318723c16ed31e76bb4477da49c293e
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