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/5.3/sys/amd64/amd64/trap.c 134685 2004-09-03 06:40:26Z julian $"); 42 43 /* 44 * AMD64 Trap and System call handling 45 */ 46 47 #include "opt_clock.h" 48 #include "opt_cpu.h" 49 #include "opt_isa.h" 50 #include "opt_ktrace.h" 51 52 #include <sys/param.h> 53 #include <sys/bus.h> 54 #include <sys/systm.h> 55 #include <sys/proc.h> 56 #include <sys/pioctl.h> 57 #include <sys/ptrace.h> 58 #include <sys/kdb.h> 59 #include <sys/kernel.h> 60 #include <sys/ktr.h> 61 #include <sys/lock.h> 62 #include <sys/mutex.h> 63 #include <sys/resourcevar.h> 64 #include <sys/signalvar.h> 65 #include <sys/syscall.h> 66 #include <sys/sysctl.h> 67 #include <sys/sysent.h> 68 #include <sys/uio.h> 69 #include <sys/vmmeter.h> 70 #ifdef KTRACE 71 #include <sys/ktrace.h> 72 #endif 73 74 #include <vm/vm.h> 75 #include <vm/vm_param.h> 76 #include <vm/pmap.h> 77 #include <vm/vm_kern.h> 78 #include <vm/vm_map.h> 79 #include <vm/vm_page.h> 80 #include <vm/vm_extern.h> 81 82 #include <machine/cpu.h> 83 #include <machine/intr_machdep.h> 84 #include <machine/md_var.h> 85 #include <machine/pcb.h> 86 #ifdef SMP 87 #include <machine/smp.h> 88 #endif 89 #include <machine/tss.h> 90 91 extern void trap(struct trapframe frame); 92 extern void syscall(struct trapframe frame); 93 94 static int trap_pfault(struct trapframe *, int); 95 static void trap_fatal(struct trapframe *, vm_offset_t); 96 void dblfault_handler(void); 97 98 #define MAX_TRAP_MSG 28 99 static char *trap_msg[] = { 100 "", /* 0 unused */ 101 "privileged instruction fault", /* 1 T_PRIVINFLT */ 102 "", /* 2 unused */ 103 "breakpoint instruction fault", /* 3 T_BPTFLT */ 104 "", /* 4 unused */ 105 "", /* 5 unused */ 106 "arithmetic trap", /* 6 T_ARITHTRAP */ 107 "", /* 7 unused */ 108 "", /* 8 unused */ 109 "general protection fault", /* 9 T_PROTFLT */ 110 "trace trap", /* 10 T_TRCTRAP */ 111 "", /* 11 unused */ 112 "page fault", /* 12 T_PAGEFLT */ 113 "", /* 13 unused */ 114 "alignment fault", /* 14 T_ALIGNFLT */ 115 "", /* 15 unused */ 116 "", /* 16 unused */ 117 "", /* 17 unused */ 118 "integer divide fault", /* 18 T_DIVIDE */ 119 "non-maskable interrupt trap", /* 19 T_NMI */ 120 "overflow trap", /* 20 T_OFLOW */ 121 "FPU bounds check fault", /* 21 T_BOUND */ 122 "FPU device not available", /* 22 T_DNA */ 123 "double fault", /* 23 T_DOUBLEFLT */ 124 "FPU operand fetch fault", /* 24 T_FPOPFLT */ 125 "invalid TSS fault", /* 25 T_TSSFLT */ 126 "segment not present fault", /* 26 T_SEGNPFLT */ 127 "stack fault", /* 27 T_STKFLT */ 128 "machine check trap", /* 28 T_MCHK */ 129 }; 130 131 #ifdef KDB 132 static int kdb_on_nmi = 1; 133 SYSCTL_INT(_machdep, OID_AUTO, kdb_on_nmi, CTLFLAG_RW, 134 &kdb_on_nmi, 0, "Go to KDB on NMI"); 135 #endif 136 static int panic_on_nmi = 1; 137 SYSCTL_INT(_machdep, OID_AUTO, panic_on_nmi, CTLFLAG_RW, 138 &panic_on_nmi, 0, "Panic on NMI"); 139 140 #ifdef WITNESS 141 extern char *syscallnames[]; 142 #endif 143 144 #ifdef DEVICE_POLLING 145 extern u_int32_t poll_in_trap; 146 extern int ether_poll(int count); 147 #endif /* DEVICE_POLLING */ 148 149 /* 150 * Exception, fault, and trap interface to the FreeBSD kernel. 151 * This common code is called from assembly language IDT gate entry 152 * routines that prepare a suitable stack frame, and restore this 153 * frame after the exception has been processed. 154 */ 155 156 void 157 trap(frame) 158 struct trapframe frame; 159 { 160 struct thread *td = curthread; 161 struct proc *p = td->td_proc; 162 u_int sticks = 0; 163 int i = 0, ucode = 0, type, code; 164 165 atomic_add_int(&cnt.v_trap, 1); 166 type = frame.tf_trapno; 167 168 #ifdef KDB 169 if (kdb_active) { 170 kdb_reenter(); 171 goto out; 172 } 173 #endif 174 175 if ((frame.tf_rflags & PSL_I) == 0) { 176 /* 177 * Buggy application or kernel code has disabled 178 * interrupts and then trapped. Enabling interrupts 179 * now is wrong, but it is better than running with 180 * interrupts disabled until they are accidentally 181 * enabled later. 182 */ 183 if (ISPL(frame.tf_cs) == SEL_UPL) 184 printf( 185 "pid %ld (%s): trap %d with interrupts disabled\n", 186 (long)curproc->p_pid, curproc->p_comm, type); 187 else if (type != T_BPTFLT && type != T_TRCTRAP) { 188 /* 189 * XXX not quite right, since this may be for a 190 * multiple fault in user mode. 191 */ 192 printf("kernel trap %d with interrupts disabled\n", 193 type); 194 /* 195 * We shouldn't enable interrupts while in a critical 196 * section. 197 */ 198 if (td->td_critnest == 0) 199 enable_intr(); 200 } 201 } 202 203 code = frame.tf_err; 204 if (type == T_PAGEFLT) { 205 /* 206 * If we get a page fault while in a critical section, then 207 * it is most likely a fatal kernel page fault. The kernel 208 * is already going to panic trying to get a sleep lock to 209 * do the VM lookup, so just consider it a fatal trap so the 210 * kernel can print out a useful trap message and even get 211 * to the debugger. 212 */ 213 if (td->td_critnest != 0) 214 trap_fatal(&frame, frame.tf_addr); 215 } 216 217 #ifdef DEVICE_POLLING 218 if (poll_in_trap) 219 ether_poll(poll_in_trap); 220 #endif /* DEVICE_POLLING */ 221 222 if (ISPL(frame.tf_cs) == SEL_UPL) { 223 /* user trap */ 224 225 sticks = td->td_sticks; 226 td->td_frame = &frame; 227 if (td->td_ucred != p->p_ucred) 228 cred_update_thread(td); 229 230 switch (type) { 231 case T_PRIVINFLT: /* privileged instruction fault */ 232 ucode = type; 233 i = SIGILL; 234 break; 235 236 case T_BPTFLT: /* bpt instruction fault */ 237 case T_TRCTRAP: /* trace trap */ 238 enable_intr(); 239 frame.tf_rflags &= ~PSL_T; 240 i = SIGTRAP; 241 break; 242 243 case T_ARITHTRAP: /* arithmetic trap */ 244 ucode = fputrap(); 245 if (ucode == -1) 246 goto userout; 247 i = SIGFPE; 248 break; 249 250 case T_PROTFLT: /* general protection fault */ 251 case T_STKFLT: /* stack fault */ 252 case T_SEGNPFLT: /* segment not present fault */ 253 case T_TSSFLT: /* invalid TSS fault */ 254 case T_DOUBLEFLT: /* double fault */ 255 default: 256 ucode = code + BUS_SEGM_FAULT ; 257 i = SIGBUS; 258 break; 259 260 case T_PAGEFLT: /* page fault */ 261 if (td->td_pflags & TDP_SA) 262 thread_user_enter(td); 263 i = trap_pfault(&frame, TRUE); 264 if (i == -1) 265 goto userout; 266 if (i == 0) 267 goto user; 268 269 ucode = T_PAGEFLT; 270 break; 271 272 case T_DIVIDE: /* integer divide fault */ 273 ucode = FPE_INTDIV; 274 i = SIGFPE; 275 break; 276 277 #ifdef DEV_ISA 278 case T_NMI: 279 /* machine/parity/power fail/"kitchen sink" faults */ 280 /* XXX Giant */ 281 if (isa_nmi(code) == 0) { 282 #ifdef KDB 283 /* 284 * NMI can be hooked up to a pushbutton 285 * for debugging. 286 */ 287 if (kdb_on_nmi) { 288 printf ("NMI ... going to debugger\n"); 289 kdb_trap(type, 0, &frame); 290 } 291 #endif /* KDB */ 292 goto userout; 293 } else if (panic_on_nmi) 294 panic("NMI indicates hardware failure"); 295 break; 296 #endif /* DEV_ISA */ 297 298 case T_OFLOW: /* integer overflow fault */ 299 ucode = FPE_INTOVF; 300 i = SIGFPE; 301 break; 302 303 case T_BOUND: /* bounds check fault */ 304 ucode = FPE_FLTSUB; 305 i = SIGFPE; 306 break; 307 308 case T_DNA: 309 /* transparent fault (due to context switch "late") */ 310 if (fpudna()) 311 goto userout; 312 i = SIGFPE; 313 ucode = FPE_FPU_NP_TRAP; 314 break; 315 316 case T_FPOPFLT: /* FPU operand fetch fault */ 317 ucode = T_FPOPFLT; 318 i = SIGILL; 319 break; 320 321 case T_XMMFLT: /* SIMD floating-point exception */ 322 ucode = 0; /* XXX */ 323 i = SIGFPE; 324 break; 325 } 326 } else { 327 /* kernel trap */ 328 329 KASSERT(cold || td->td_ucred != NULL, 330 ("kernel trap doesn't have ucred")); 331 switch (type) { 332 case T_PAGEFLT: /* page fault */ 333 (void) trap_pfault(&frame, FALSE); 334 goto out; 335 336 case T_DNA: 337 /* 338 * The kernel is apparently using fpu for copying. 339 * XXX this should be fatal unless the kernel has 340 * registered such use. 341 */ 342 if (fpudna()) { 343 printf("fpudna in kernel mode!\n"); 344 goto out; 345 } 346 break; 347 348 case T_STKFLT: /* stack fault */ 349 break; 350 351 case T_PROTFLT: /* general protection fault */ 352 case T_SEGNPFLT: /* segment not present fault */ 353 if (td->td_intr_nesting_level != 0) 354 break; 355 356 /* 357 * Invalid segment selectors and out of bounds 358 * %eip's and %esp's can be set up in user mode. 359 * This causes a fault in kernel mode when the 360 * kernel tries to return to user mode. We want 361 * to get this fault so that we can fix the 362 * problem here and not have to check all the 363 * selectors and pointers when the user changes 364 * them. 365 */ 366 if (frame.tf_rip == (long)doreti_iret) { 367 frame.tf_rip = (long)doreti_iret_fault; 368 goto out; 369 } 370 if (PCPU_GET(curpcb)->pcb_onfault != NULL) { 371 frame.tf_rip = 372 (long)PCPU_GET(curpcb)->pcb_onfault; 373 goto out; 374 } 375 break; 376 377 case T_TSSFLT: 378 /* 379 * PSL_NT can be set in user mode and isn't cleared 380 * automatically when the kernel is entered. This 381 * causes a TSS fault when the kernel attempts to 382 * `iret' because the TSS link is uninitialized. We 383 * want to get this fault so that we can fix the 384 * problem here and not every time the kernel is 385 * entered. 386 */ 387 if (frame.tf_rflags & PSL_NT) { 388 frame.tf_rflags &= ~PSL_NT; 389 goto out; 390 } 391 break; 392 393 case T_TRCTRAP: /* trace trap */ 394 /* 395 * Ignore debug register trace traps due to 396 * accesses in the user's address space, which 397 * can happen under several conditions such as 398 * if a user sets a watchpoint on a buffer and 399 * then passes that buffer to a system call. 400 * We still want to get TRCTRAPS for addresses 401 * in kernel space because that is useful when 402 * debugging the kernel. 403 */ 404 if (user_dbreg_trap()) { 405 /* 406 * Reset breakpoint bits because the 407 * processor doesn't 408 */ 409 /* XXX check upper bits here */ 410 load_dr6(rdr6() & 0xfffffff0); 411 goto out; 412 } 413 /* 414 * FALLTHROUGH (TRCTRAP kernel mode, kernel address) 415 */ 416 case T_BPTFLT: 417 /* 418 * If KDB is enabled, let it handle the debugger trap. 419 * Otherwise, debugger traps "can't happen". 420 */ 421 #ifdef KDB 422 /* XXX Giant */ 423 if (kdb_trap(type, 0, &frame)) 424 goto out; 425 #endif 426 break; 427 428 #ifdef DEV_ISA 429 case T_NMI: 430 /* XXX Giant */ 431 /* machine/parity/power fail/"kitchen sink" faults */ 432 if (isa_nmi(code) == 0) { 433 #ifdef KDB 434 /* 435 * NMI can be hooked up to a pushbutton 436 * for debugging. 437 */ 438 if (kdb_on_nmi) { 439 printf ("NMI ... going to debugger\n"); 440 kdb_trap(type, 0, &frame); 441 } 442 #endif /* KDB */ 443 goto out; 444 } else if (panic_on_nmi == 0) 445 goto out; 446 /* FALLTHROUGH */ 447 #endif /* DEV_ISA */ 448 } 449 450 trap_fatal(&frame, 0); 451 goto out; 452 } 453 454 /* Translate fault for emulators (e.g. Linux) */ 455 if (*p->p_sysent->sv_transtrap) 456 i = (*p->p_sysent->sv_transtrap)(i, type); 457 458 trapsignal(td, i, ucode); 459 460 #ifdef DEBUG 461 if (type <= MAX_TRAP_MSG) { 462 uprintf("fatal process exception: %s", 463 trap_msg[type]); 464 if ((type == T_PAGEFLT) || (type == T_PROTFLT)) 465 uprintf(", fault VA = 0x%lx", frame.tf_addr); 466 uprintf("\n"); 467 } 468 #endif 469 470 user: 471 userret(td, &frame, sticks); 472 mtx_assert(&Giant, MA_NOTOWNED); 473 userout: 474 out: 475 return; 476 } 477 478 static int 479 trap_pfault(frame, usermode) 480 struct trapframe *frame; 481 int usermode; 482 { 483 vm_offset_t va; 484 struct vmspace *vm = NULL; 485 vm_map_t map = 0; 486 int rv = 0; 487 vm_prot_t ftype; 488 struct thread *td = curthread; 489 struct proc *p = td->td_proc; 490 vm_offset_t eva = frame->tf_addr; 491 492 va = trunc_page(eva); 493 if (va >= KERNBASE) { 494 /* 495 * Don't allow user-mode faults in kernel address space. 496 */ 497 if (usermode) 498 goto nogo; 499 500 map = kernel_map; 501 } else { 502 /* 503 * This is a fault on non-kernel virtual memory. 504 * vm is initialized above to NULL. If curproc is NULL 505 * or curproc->p_vmspace is NULL the fault is fatal. 506 */ 507 if (p != NULL) 508 vm = p->p_vmspace; 509 510 if (vm == NULL) 511 goto nogo; 512 513 map = &vm->vm_map; 514 } 515 516 if (frame->tf_err & PGEX_W) 517 ftype = VM_PROT_WRITE; 518 else 519 ftype = VM_PROT_READ; 520 521 if (map != kernel_map) { 522 /* 523 * Keep swapout from messing with us during this 524 * critical time. 525 */ 526 PROC_LOCK(p); 527 ++p->p_lock; 528 PROC_UNLOCK(p); 529 530 /* Fault in the user page: */ 531 rv = vm_fault(map, va, ftype, 532 (ftype & VM_PROT_WRITE) ? VM_FAULT_DIRTY 533 : VM_FAULT_NORMAL); 534 535 PROC_LOCK(p); 536 --p->p_lock; 537 PROC_UNLOCK(p); 538 } else { 539 /* 540 * Don't have to worry about process locking or stacks in the 541 * kernel. 542 */ 543 rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL); 544 } 545 if (rv == KERN_SUCCESS) 546 return (0); 547 nogo: 548 if (!usermode) { 549 if (td->td_intr_nesting_level == 0 && 550 PCPU_GET(curpcb)->pcb_onfault != NULL) { 551 frame->tf_rip = (long)PCPU_GET(curpcb)->pcb_onfault; 552 return (0); 553 } 554 trap_fatal(frame, eva); 555 return (-1); 556 } 557 558 return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV); 559 } 560 561 static void 562 trap_fatal(frame, eva) 563 struct trapframe *frame; 564 vm_offset_t eva; 565 { 566 int code, type, ss; 567 long esp; 568 struct soft_segment_descriptor softseg; 569 570 code = frame->tf_err; 571 type = frame->tf_trapno; 572 sdtossd(&gdt[IDXSEL(frame->tf_cs & 0xffff)], &softseg); 573 574 if (type <= MAX_TRAP_MSG) 575 printf("\n\nFatal trap %d: %s while in %s mode\n", 576 type, trap_msg[type], 577 ISPL(frame->tf_cs) == SEL_UPL ? "user" : "kernel"); 578 #ifdef SMP 579 /* two separate prints in case of a trap on an unmapped page */ 580 printf("cpuid = %d; ", PCPU_GET(cpuid)); 581 printf("apic id = %02x\n", PCPU_GET(apic_id)); 582 #endif 583 if (type == T_PAGEFLT) { 584 printf("fault virtual address = 0x%lx\n", eva); 585 printf("fault code = %s %s, %s\n", 586 code & PGEX_U ? "user" : "supervisor", 587 code & PGEX_W ? "write" : "read", 588 code & PGEX_P ? "protection violation" : "page not present"); 589 } 590 printf("instruction pointer = 0x%lx:0x%lx\n", 591 frame->tf_cs & 0xffff, frame->tf_rip); 592 if (ISPL(frame->tf_cs) == SEL_UPL) { 593 ss = frame->tf_ss & 0xffff; 594 esp = frame->tf_rsp; 595 } else { 596 ss = GSEL(GDATA_SEL, SEL_KPL); 597 esp = (long)&frame->tf_rsp; 598 } 599 printf("stack pointer = 0x%x:0x%lx\n", ss, esp); 600 printf("frame pointer = 0x%x:0x%lx\n", ss, frame->tf_rbp); 601 printf("code segment = base 0x%lx, limit 0x%lx, type 0x%x\n", 602 softseg.ssd_base, softseg.ssd_limit, softseg.ssd_type); 603 printf(" = DPL %d, pres %d, long %d, def32 %d, gran %d\n", 604 softseg.ssd_dpl, softseg.ssd_p, softseg.ssd_long, softseg.ssd_def32, 605 softseg.ssd_gran); 606 printf("processor eflags = "); 607 if (frame->tf_rflags & PSL_T) 608 printf("trace trap, "); 609 if (frame->tf_rflags & PSL_I) 610 printf("interrupt enabled, "); 611 if (frame->tf_rflags & PSL_NT) 612 printf("nested task, "); 613 if (frame->tf_rflags & PSL_RF) 614 printf("resume, "); 615 printf("IOPL = %ld\n", (frame->tf_rflags & PSL_IOPL) >> 12); 616 printf("current process = "); 617 if (curproc) { 618 printf("%lu (%s)\n", 619 (u_long)curproc->p_pid, curproc->p_comm ? 620 curproc->p_comm : ""); 621 } else { 622 printf("Idle\n"); 623 } 624 625 #ifdef KDB 626 if (kdb_trap(type, 0, frame)) 627 return; 628 #endif 629 printf("trap number = %d\n", type); 630 if (type <= MAX_TRAP_MSG) 631 panic("%s", trap_msg[type]); 632 else 633 panic("unknown/reserved trap"); 634 } 635 636 /* 637 * Double fault handler. Called when a fault occurs while writing 638 * a frame for a trap/exception onto the stack. This usually occurs 639 * when the stack overflows (such is the case with infinite recursion, 640 * for example). 641 */ 642 void 643 dblfault_handler() 644 { 645 printf("\nFatal double fault\n"); 646 #ifdef SMP 647 /* two separate prints in case of a trap on an unmapped page */ 648 printf("cpuid = %d; ", PCPU_GET(cpuid)); 649 printf("apic id = %02x\n", PCPU_GET(apic_id)); 650 #endif 651 panic("double fault"); 652 } 653 654 /* 655 * syscall - system call request C handler 656 * 657 * A system call is essentially treated as a trap. 658 */ 659 void 660 syscall(frame) 661 struct trapframe frame; 662 { 663 caddr_t params; 664 struct sysent *callp; 665 struct thread *td = curthread; 666 struct proc *p = td->td_proc; 667 register_t orig_tf_rflags; 668 u_int sticks; 669 int error; 670 int narg; 671 register_t args[8]; 672 register_t *argp; 673 u_int code; 674 int reg, regcnt; 675 676 /* 677 * note: PCPU_LAZY_INC() can only be used if we can afford 678 * occassional inaccuracy in the count. 679 */ 680 PCPU_LAZY_INC(cnt.v_syscall); 681 682 #ifdef DIAGNOSTIC 683 if (ISPL(frame.tf_cs) != SEL_UPL) { 684 mtx_lock(&Giant); /* try to stabilize the system XXX */ 685 panic("syscall"); 686 /* NOT REACHED */ 687 mtx_unlock(&Giant); 688 } 689 #endif 690 691 reg = 0; 692 regcnt = 6; 693 sticks = td->td_sticks; 694 td->td_frame = &frame; 695 if (td->td_ucred != p->p_ucred) 696 cred_update_thread(td); 697 if (p->p_flag & P_SA) 698 thread_user_enter(td); 699 params = (caddr_t)frame.tf_rsp + sizeof(register_t); 700 code = frame.tf_rax; 701 orig_tf_rflags = frame.tf_rflags; 702 703 if (p->p_sysent->sv_prepsyscall) { 704 /* 705 * The prep code is MP aware. 706 */ 707 (*p->p_sysent->sv_prepsyscall)(&frame, (int *)args, &code, ¶ms); 708 } else { 709 if (code == SYS_syscall || code == SYS___syscall) { 710 code = frame.tf_rdi; 711 reg++; 712 regcnt--; 713 } 714 } 715 716 if (p->p_sysent->sv_mask) 717 code &= p->p_sysent->sv_mask; 718 719 if (code >= p->p_sysent->sv_size) 720 callp = &p->p_sysent->sv_table[0]; 721 else 722 callp = &p->p_sysent->sv_table[code]; 723 724 narg = callp->sy_narg & SYF_ARGMASK; 725 726 /* 727 * copyin and the ktrsyscall()/ktrsysret() code is MP-aware 728 */ 729 KASSERT(narg <= sizeof(args) / sizeof(args[0]), 730 ("Too many syscall arguments!")); 731 error = 0; 732 argp = &frame.tf_rdi; 733 argp += reg; 734 bcopy(argp, args, sizeof(args[0]) * regcnt); 735 if (narg > regcnt) { 736 KASSERT(params != NULL, ("copyin args with no params!")); 737 error = copyin(params, &args[regcnt], 738 (narg - regcnt) * sizeof(args[0])); 739 } 740 argp = &args[0]; 741 742 #ifdef KTRACE 743 if (KTRPOINT(td, KTR_SYSCALL)) 744 ktrsyscall(code, narg, argp); 745 #endif 746 747 CTR4(KTR_SYSC, "syscall enter thread %p pid %d proc %s code %d", td, 748 td->td_proc->p_pid, td->td_proc->p_comm, code); 749 750 if (error == 0) { 751 td->td_retval[0] = 0; 752 td->td_retval[1] = frame.tf_rdx; 753 754 STOPEVENT(p, S_SCE, narg); 755 756 PTRACESTOP_SC(p, td, S_PT_SCE); 757 758 if ((callp->sy_narg & SYF_MPSAFE) == 0) { 759 mtx_lock(&Giant); 760 error = (*callp->sy_call)(td, argp); 761 mtx_unlock(&Giant); 762 } else 763 error = (*callp->sy_call)(td, argp); 764 } 765 766 switch (error) { 767 case 0: 768 frame.tf_rax = td->td_retval[0]; 769 frame.tf_rdx = td->td_retval[1]; 770 frame.tf_rflags &= ~PSL_C; 771 break; 772 773 case ERESTART: 774 /* 775 * Reconstruct pc, we know that 'syscall' is 2 bytes. 776 * We have to do a full context restore so that %r10 777 * (which was holding the value of %rcx) is restored for 778 * the next iteration. 779 */ 780 frame.tf_rip -= frame.tf_err; 781 frame.tf_r10 = frame.tf_rcx; 782 td->td_pcb->pcb_flags |= PCB_FULLCTX; 783 break; 784 785 case EJUSTRETURN: 786 break; 787 788 default: 789 if (p->p_sysent->sv_errsize) { 790 if (error >= p->p_sysent->sv_errsize) 791 error = -1; /* XXX */ 792 else 793 error = p->p_sysent->sv_errtbl[error]; 794 } 795 frame.tf_rax = error; 796 frame.tf_rflags |= PSL_C; 797 break; 798 } 799 800 /* 801 * Traced syscall. 802 */ 803 if (orig_tf_rflags & PSL_T) { 804 frame.tf_rflags &= ~PSL_T; 805 trapsignal(td, SIGTRAP, 0); 806 } 807 808 /* 809 * Handle reschedule and other end-of-syscall issues 810 */ 811 userret(td, &frame, sticks); 812 813 CTR4(KTR_SYSC, "syscall exit thread %p pid %d proc %s code %d", td, 814 td->td_proc->p_pid, td->td_proc->p_comm, code); 815 816 #ifdef KTRACE 817 if (KTRPOINT(td, KTR_SYSRET)) 818 ktrsysret(code, error, td->td_retval[0]); 819 #endif 820 821 /* 822 * This works because errno is findable through the 823 * register set. If we ever support an emulation where this 824 * is not the case, this code will need to be revisited. 825 */ 826 STOPEVENT(p, S_SCX, code); 827 828 PTRACESTOP_SC(p, td, S_PT_SCX); 829 830 WITNESS_WARN(WARN_PANIC, NULL, "System call %s returning", 831 (code >= 0 && code < SYS_MAXSYSCALL) ? syscallnames[code] : "???"); 832 mtx_assert(&sched_lock, MA_NOTOWNED); 833 mtx_assert(&Giant, MA_NOTOWNED); 834 }
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