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 * $FreeBSD: src/sys/i386/i386/trap.c,v 1.147.2.11 2003/02/27 19:09:59 luoqi Exp $ 39 */ 40 41 /* 42 * x86_64 Trap and System call handling 43 */ 44 45 #include "use_isa.h" 46 47 #include "opt_ddb.h" 48 #include "opt_ktrace.h" 49 50 #include <sys/param.h> 51 #include <sys/systm.h> 52 #include <sys/proc.h> 53 #include <sys/pioctl.h> 54 #include <sys/kernel.h> 55 #include <sys/resourcevar.h> 56 #include <sys/signalvar.h> 57 #include <sys/signal2.h> 58 #include <sys/syscall.h> 59 #include <sys/sysctl.h> 60 #include <sys/sysent.h> 61 #include <sys/uio.h> 62 #include <sys/vmmeter.h> 63 #include <sys/malloc.h> 64 #ifdef KTRACE 65 #include <sys/ktrace.h> 66 #endif 67 #include <sys/ktr.h> 68 #include <sys/upcall.h> 69 #include <sys/vkernel.h> 70 #include <sys/sysproto.h> 71 #include <sys/sysunion.h> 72 #include <sys/vmspace.h> 73 74 #include <vm/vm.h> 75 #include <vm/vm_param.h> 76 #include <sys/lock.h> 77 #include <vm/pmap.h> 78 #include <vm/vm_kern.h> 79 #include <vm/vm_map.h> 80 #include <vm/vm_page.h> 81 #include <vm/vm_extern.h> 82 83 #include <machine/cpu.h> 84 #include <machine/md_var.h> 85 #include <machine/pcb.h> 86 #include <machine/smp.h> 87 #include <machine/tss.h> 88 #include <machine/globaldata.h> 89 90 #include <ddb/ddb.h> 91 92 #include <sys/msgport2.h> 93 #include <sys/thread2.h> 94 #include <sys/mplock2.h> 95 96 #ifdef SMP 97 98 #define MAKEMPSAFE(have_mplock) \ 99 if (have_mplock == 0) { \ 100 get_mplock(); \ 101 have_mplock = 1; \ 102 } 103 104 #else 105 106 #define MAKEMPSAFE(have_mplock) 107 108 #endif 109 110 int (*pmath_emulate) (struct trapframe *); 111 112 extern int trapwrite (unsigned addr); 113 114 static int trap_pfault (struct trapframe *, int, vm_offset_t); 115 static void trap_fatal (struct trapframe *, int, vm_offset_t); 116 void dblfault_handler (void); 117 118 #if 0 119 extern inthand_t IDTVEC(syscall); 120 #endif 121 122 #define MAX_TRAP_MSG 30 123 static char *trap_msg[] = { 124 "", /* 0 unused */ 125 "privileged instruction fault", /* 1 T_PRIVINFLT */ 126 "", /* 2 unused */ 127 "breakpoint instruction fault", /* 3 T_BPTFLT */ 128 "", /* 4 unused */ 129 "", /* 5 unused */ 130 "arithmetic trap", /* 6 T_ARITHTRAP */ 131 "system forced exception", /* 7 T_ASTFLT */ 132 "", /* 8 unused */ 133 "general protection fault", /* 9 T_PROTFLT */ 134 "trace trap", /* 10 T_TRCTRAP */ 135 "", /* 11 unused */ 136 "page fault", /* 12 T_PAGEFLT */ 137 "", /* 13 unused */ 138 "alignment fault", /* 14 T_ALIGNFLT */ 139 "", /* 15 unused */ 140 "", /* 16 unused */ 141 "", /* 17 unused */ 142 "integer divide fault", /* 18 T_DIVIDE */ 143 "non-maskable interrupt trap", /* 19 T_NMI */ 144 "overflow trap", /* 20 T_OFLOW */ 145 "FPU bounds check fault", /* 21 T_BOUND */ 146 "FPU device not available", /* 22 T_DNA */ 147 "double fault", /* 23 T_DOUBLEFLT */ 148 "FPU operand fetch fault", /* 24 T_FPOPFLT */ 149 "invalid TSS fault", /* 25 T_TSSFLT */ 150 "segment not present fault", /* 26 T_SEGNPFLT */ 151 "stack fault", /* 27 T_STKFLT */ 152 "machine check trap", /* 28 T_MCHK */ 153 "SIMD floating-point exception", /* 29 T_XMMFLT */ 154 "reserved (unknown) fault", /* 30 T_RESERVED */ 155 }; 156 157 #ifdef DDB 158 static int ddb_on_nmi = 1; 159 SYSCTL_INT(_machdep, OID_AUTO, ddb_on_nmi, CTLFLAG_RW, 160 &ddb_on_nmi, 0, "Go to DDB on NMI"); 161 #endif 162 static int panic_on_nmi = 1; 163 SYSCTL_INT(_machdep, OID_AUTO, panic_on_nmi, CTLFLAG_RW, 164 &panic_on_nmi, 0, "Panic on NMI"); 165 static int fast_release; 166 SYSCTL_INT(_machdep, OID_AUTO, fast_release, CTLFLAG_RW, 167 &fast_release, 0, "Passive Release was optimal"); 168 static int slow_release; 169 SYSCTL_INT(_machdep, OID_AUTO, slow_release, CTLFLAG_RW, 170 &slow_release, 0, "Passive Release was nonoptimal"); 171 172 MALLOC_DEFINE(M_SYSMSG, "sysmsg", "sysmsg structure"); 173 extern int max_sysmsg; 174 175 /* 176 * Passively intercepts the thread switch function to increase the thread 177 * priority from a user priority to a kernel priority, reducing 178 * syscall and trap overhead for the case where no switch occurs. 179 * 180 * Synchronizes td_ucred with p_ucred. This is used by system calls, 181 * signal handling, faults, AST traps, and anything else that enters the 182 * kernel from userland and provides the kernel with a stable read-only 183 * copy of the process ucred. 184 */ 185 static __inline void 186 userenter(struct thread *curtd, struct proc *curp) 187 { 188 struct ucred *ocred; 189 struct ucred *ncred; 190 191 curtd->td_release = lwkt_passive_release; 192 193 if (curtd->td_ucred != curp->p_ucred) { 194 ncred = crhold(curp->p_ucred); 195 ocred = curtd->td_ucred; 196 curtd->td_ucred = ncred; 197 if (ocred) 198 crfree(ocred); 199 } 200 } 201 202 /* 203 * Handle signals, upcalls, profiling, and other AST's and/or tasks that 204 * must be completed before we can return to or try to return to userland. 205 * 206 * Note that td_sticks is a 64 bit quantity, but there's no point doing 64 207 * arithmatic on the delta calculation so the absolute tick values are 208 * truncated to an integer. 209 */ 210 static void 211 userret(struct lwp *lp, struct trapframe *frame, int sticks) 212 { 213 struct proc *p = lp->lwp_proc; 214 int sig; 215 216 /* 217 * Charge system time if profiling. Note: times are in microseconds. 218 * This may do a copyout and block, so do it first even though it 219 * means some system time will be charged as user time. 220 */ 221 if (p->p_flag & P_PROFIL) { 222 addupc_task(p, frame->tf_rip, 223 (u_int)((int)lp->lwp_thread->td_sticks - sticks)); 224 } 225 226 recheck: 227 /* 228 * If the jungle wants us dead, so be it. 229 */ 230 if (lp->lwp_flag & LWP_WEXIT) { 231 get_mplock(); 232 lwp_exit(0); 233 rel_mplock(); /* NOT REACHED */ 234 } 235 236 /* 237 * Block here if we are in a stopped state. 238 */ 239 if (p->p_stat == SSTOP) { 240 get_mplock(); 241 tstop(); 242 rel_mplock(); 243 goto recheck; 244 } 245 246 /* 247 * Post any pending upcalls 248 */ 249 if (p->p_flag & P_UPCALLPEND) { 250 get_mplock(); 251 p->p_flag &= ~P_UPCALLPEND; 252 postupcall(lp); 253 rel_mplock(); 254 goto recheck; 255 } 256 257 /* 258 * Post any pending signals 259 * 260 * WARNING! postsig() can exit and not return. 261 */ 262 if ((sig = CURSIG_TRACE(lp)) != 0) { 263 get_mplock(); 264 postsig(sig); 265 rel_mplock(); 266 goto recheck; 267 } 268 269 /* 270 * block here if we are swapped out, but still process signals 271 * (such as SIGKILL). proc0 (the swapin scheduler) is already 272 * aware of our situation, we do not have to wake it up. 273 */ 274 if (p->p_flag & P_SWAPPEDOUT) { 275 get_mplock(); 276 p->p_flag |= P_SWAPWAIT; 277 swapin_request(); 278 if (p->p_flag & P_SWAPWAIT) 279 tsleep(p, PCATCH, "SWOUT", 0); 280 p->p_flag &= ~P_SWAPWAIT; 281 rel_mplock(); 282 goto recheck; 283 } 284 285 /* 286 * Make sure postsig() handled request to restore old signal mask after 287 * running signal handler. 288 */ 289 KKASSERT((lp->lwp_flag & LWP_OLDMASK) == 0); 290 } 291 292 /* 293 * Cleanup from userenter and any passive release that might have occured. 294 * We must reclaim the current-process designation before we can return 295 * to usermode. We also handle both LWKT and USER reschedule requests. 296 */ 297 static __inline void 298 userexit(struct lwp *lp) 299 { 300 struct thread *td = lp->lwp_thread; 301 /* globaldata_t gd = td->td_gd; */ 302 303 /* 304 * Handle stop requests at kernel priority. Any requests queued 305 * after this loop will generate another AST. 306 */ 307 while (lp->lwp_proc->p_stat == SSTOP) { 308 get_mplock(); 309 tstop(); 310 rel_mplock(); 311 } 312 313 /* 314 * Reduce our priority in preparation for a return to userland. If 315 * our passive release function was still in place, our priority was 316 * never raised and does not need to be reduced. 317 */ 318 lwkt_passive_recover(td); 319 320 /* 321 * Become the current user scheduled process if we aren't already, 322 * and deal with reschedule requests and other factors. 323 */ 324 lp->lwp_proc->p_usched->acquire_curproc(lp); 325 /* WARNING: we may have migrated cpu's */ 326 /* gd = td->td_gd; */ 327 } 328 329 #if !defined(KTR_KERNENTRY) 330 #define KTR_KERNENTRY KTR_ALL 331 #endif 332 KTR_INFO_MASTER(kernentry); 333 KTR_INFO(KTR_KERNENTRY, kernentry, trap, 0, "pid=%d, tid=%d, trapno=%d, eva=%p", 334 sizeof(int) + sizeof(int) + sizeof(int) + sizeof(vm_offset_t)); 335 KTR_INFO(KTR_KERNENTRY, kernentry, trap_ret, 0, "pid=%d, tid=%d", 336 sizeof(int) + sizeof(int)); 337 KTR_INFO(KTR_KERNENTRY, kernentry, syscall, 0, "pid=%d, tid=%d, call=%d", 338 sizeof(int) + sizeof(int) + sizeof(int)); 339 KTR_INFO(KTR_KERNENTRY, kernentry, syscall_ret, 0, "pid=%d, tid=%d, err=%d", 340 sizeof(int) + sizeof(int) + sizeof(int)); 341 KTR_INFO(KTR_KERNENTRY, kernentry, fork_ret, 0, "pid=%d, tid=%d", 342 sizeof(int) + sizeof(int)); 343 344 /* 345 * Exception, fault, and trap interface to the kernel. 346 * This common code is called from assembly language IDT gate entry 347 * routines that prepare a suitable stack frame, and restore this 348 * frame after the exception has been processed. 349 * 350 * This function is also called from doreti in an interlock to handle ASTs. 351 * For example: hardwareint->INTROUTINE->(set ast)->doreti->trap 352 * 353 * NOTE! We have to retrieve the fault address prior to obtaining the 354 * MP lock because get_mplock() may switch out. YYY cr2 really ought 355 * to be retrieved by the assembly code, not here. 356 * 357 * XXX gd_trap_nesting_level currently prevents lwkt_switch() from panicing 358 * if an attempt is made to switch from a fast interrupt or IPI. This is 359 * necessary to properly take fatal kernel traps on SMP machines if 360 * get_mplock() has to block. 361 */ 362 363 void 364 user_trap(struct trapframe *frame) 365 { 366 struct globaldata *gd = mycpu; 367 struct thread *td = gd->gd_curthread; 368 struct lwp *lp = td->td_lwp; 369 struct proc *p; 370 int sticks = 0; 371 int i = 0, ucode = 0, type, code; 372 #ifdef SMP 373 int have_mplock = 0; 374 #endif 375 #ifdef INVARIANTS 376 int crit_count = td->td_critcount; 377 lwkt_tokref_t curstop = td->td_toks_stop; 378 #endif 379 vm_offset_t eva; 380 381 p = td->td_proc; 382 383 if (frame->tf_trapno == T_PAGEFLT) 384 eva = frame->tf_addr; 385 else 386 eva = 0; 387 #if 0 388 kprintf("USER_TRAP AT %08lx xflags %ld trapno %ld eva %08lx\n", 389 frame->tf_rip, frame->tf_xflags, frame->tf_trapno, eva); 390 #endif 391 392 /* 393 * Everything coming from user mode runs through user_trap, 394 * including system calls. 395 */ 396 if (frame->tf_trapno == T_FAST_SYSCALL) { 397 syscall2(frame); 398 return; 399 } 400 401 KTR_LOG(kernentry_trap, lp->lwp_proc->p_pid, lp->lwp_tid, 402 frame->tf_trapno, eva); 403 404 #ifdef DDB 405 if (db_active) { 406 eva = (frame->tf_trapno == T_PAGEFLT ? rcr2() : 0); 407 ++gd->gd_trap_nesting_level; 408 MAKEMPSAFE(have_mplock); 409 trap_fatal(frame, TRUE, eva); 410 --gd->gd_trap_nesting_level; 411 goto out2; 412 } 413 #endif 414 415 #if defined(I586_CPU) && !defined(NO_F00F_HACK) 416 restart: 417 #endif 418 type = frame->tf_trapno; 419 code = frame->tf_err; 420 421 userenter(td, p); 422 423 sticks = (int)td->td_sticks; 424 lp->lwp_md.md_regs = frame; 425 426 switch (type) { 427 case T_PRIVINFLT: /* privileged instruction fault */ 428 ucode = type; 429 i = SIGILL; 430 break; 431 432 case T_BPTFLT: /* bpt instruction fault */ 433 case T_TRCTRAP: /* trace trap */ 434 frame->tf_rflags &= ~PSL_T; 435 i = SIGTRAP; 436 break; 437 438 case T_ARITHTRAP: /* arithmetic trap */ 439 ucode = code; 440 i = SIGFPE; 441 break; 442 443 case T_ASTFLT: /* Allow process switch */ 444 mycpu->gd_cnt.v_soft++; 445 if (mycpu->gd_reqflags & RQF_AST_OWEUPC) { 446 atomic_clear_int(&mycpu->gd_reqflags, RQF_AST_OWEUPC); 447 addupc_task(p, p->p_prof.pr_addr, p->p_prof.pr_ticks); 448 } 449 goto out; 450 451 /* 452 * The following two traps can happen in 453 * vm86 mode, and, if so, we want to handle 454 * them specially. 455 */ 456 case T_PROTFLT: /* general protection fault */ 457 case T_STKFLT: /* stack fault */ 458 #if 0 459 if (frame->tf_eflags & PSL_VM) { 460 i = vm86_emulate((struct vm86frame *)frame); 461 if (i == 0) 462 goto out; 463 break; 464 } 465 #endif 466 /* FALL THROUGH */ 467 468 case T_SEGNPFLT: /* segment not present fault */ 469 case T_TSSFLT: /* invalid TSS fault */ 470 case T_DOUBLEFLT: /* double fault */ 471 default: 472 ucode = code + BUS_SEGM_FAULT ; 473 i = SIGBUS; 474 break; 475 476 case T_PAGEFLT: /* page fault */ 477 MAKEMPSAFE(have_mplock); 478 i = trap_pfault(frame, TRUE, eva); 479 if (i == -1) 480 goto out; 481 #if defined(I586_CPU) && !defined(NO_F00F_HACK) 482 if (i == -2) 483 goto restart; 484 #endif 485 if (i == 0) 486 goto out; 487 488 ucode = T_PAGEFLT; 489 break; 490 491 case T_DIVIDE: /* integer divide fault */ 492 ucode = FPE_INTDIV; 493 i = SIGFPE; 494 break; 495 496 #if NISA > 0 497 case T_NMI: 498 MAKEMPSAFE(have_mplock); 499 /* machine/parity/power fail/"kitchen sink" faults */ 500 if (isa_nmi(code) == 0) { 501 #ifdef DDB 502 /* 503 * NMI can be hooked up to a pushbutton 504 * for debugging. 505 */ 506 if (ddb_on_nmi) { 507 kprintf ("NMI ... going to debugger\n"); 508 kdb_trap (type, 0, frame); 509 } 510 #endif /* DDB */ 511 goto out2; 512 } else if (panic_on_nmi) 513 panic("NMI indicates hardware failure"); 514 break; 515 #endif /* NISA > 0 */ 516 517 case T_OFLOW: /* integer overflow fault */ 518 ucode = FPE_INTOVF; 519 i = SIGFPE; 520 break; 521 522 case T_BOUND: /* bounds check fault */ 523 ucode = FPE_FLTSUB; 524 i = SIGFPE; 525 break; 526 527 case T_DNA: 528 /* 529 * Virtual kernel intercept - pass the DNA exception 530 * to the (emulated) virtual kernel if it asked to handle 531 * it. This occurs when the virtual kernel is holding 532 * onto the FP context for a different emulated 533 * process then the one currently running. 534 * 535 * We must still call npxdna() since we may have 536 * saved FP state that the (emulated) virtual kernel 537 * needs to hand over to a different emulated process. 538 */ 539 if (lp->lwp_vkernel && lp->lwp_vkernel->ve && 540 (td->td_pcb->pcb_flags & FP_VIRTFP) 541 ) { 542 npxdna(frame); 543 break; 544 } 545 /* 546 * The kernel may have switched out the FP unit's 547 * state, causing the user process to take a fault 548 * when it tries to use the FP unit. Restore the 549 * state here 550 */ 551 if (npxdna(frame)) 552 goto out; 553 if (!pmath_emulate) { 554 i = SIGFPE; 555 ucode = FPE_FPU_NP_TRAP; 556 break; 557 } 558 i = (*pmath_emulate)(frame); 559 if (i == 0) { 560 if (!(frame->tf_rflags & PSL_T)) 561 goto out2; 562 frame->tf_rflags &= ~PSL_T; 563 i = SIGTRAP; 564 } 565 /* else ucode = emulator_only_knows() XXX */ 566 break; 567 568 case T_FPOPFLT: /* FPU operand fetch fault */ 569 ucode = T_FPOPFLT; 570 i = SIGILL; 571 break; 572 573 case T_XMMFLT: /* SIMD floating-point exception */ 574 ucode = 0; /* XXX */ 575 i = SIGFPE; 576 break; 577 } 578 579 /* 580 * Virtual kernel intercept - if the fault is directly related to a 581 * VM context managed by a virtual kernel then let the virtual kernel 582 * handle it. 583 */ 584 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) { 585 vkernel_trap(lp, frame); 586 goto out; 587 } 588 589 /* 590 * Translate fault for emulators (e.g. Linux) 591 */ 592 if (*p->p_sysent->sv_transtrap) 593 i = (*p->p_sysent->sv_transtrap)(i, type); 594 595 MAKEMPSAFE(have_mplock); 596 trapsignal(lp, i, ucode); 597 598 #ifdef DEBUG 599 if (type <= MAX_TRAP_MSG) { 600 uprintf("fatal process exception: %s", 601 trap_msg[type]); 602 if ((type == T_PAGEFLT) || (type == T_PROTFLT)) 603 uprintf(", fault VA = 0x%lx", (u_long)eva); 604 uprintf("\n"); 605 } 606 #endif 607 608 out: 609 userret(lp, frame, sticks); 610 userexit(lp); 611 out2: ; 612 #ifdef SMP 613 if (have_mplock) 614 rel_mplock(); 615 #endif 616 KTR_LOG(kernentry_trap_ret, lp->lwp_proc->p_pid, lp->lwp_tid); 617 #ifdef INVARIANTS 618 KASSERT(crit_count == td->td_critcount, 619 ("trap: critical section count mismatch! %d/%d", 620 crit_count, td->td_pri)); 621 KASSERT(curstop == td->td_toks_stop, 622 ("trap: extra tokens held after trap! %ld/%ld", 623 curstop - &td->td_toks_base, 624 td->td_toks_stop - &td->td_toks_base)); 625 #endif 626 } 627 628 void 629 kern_trap(struct trapframe *frame) 630 { 631 struct globaldata *gd = mycpu; 632 struct thread *td = gd->gd_curthread; 633 struct lwp *lp; 634 struct proc *p; 635 int i = 0, ucode = 0, type, code; 636 #ifdef SMP 637 int have_mplock = 0; 638 #endif 639 #ifdef INVARIANTS 640 int crit_count = td->td_critcount; 641 lwkt_tokref_t curstop = td->td_toks_stop; 642 #endif 643 vm_offset_t eva; 644 645 lp = td->td_lwp; 646 p = td->td_proc; 647 648 if (frame->tf_trapno == T_PAGEFLT) 649 eva = frame->tf_addr; 650 else 651 eva = 0; 652 653 #ifdef DDB 654 if (db_active) { 655 ++gd->gd_trap_nesting_level; 656 MAKEMPSAFE(have_mplock); 657 trap_fatal(frame, FALSE, eva); 658 --gd->gd_trap_nesting_level; 659 goto out2; 660 } 661 #endif 662 663 type = frame->tf_trapno; 664 code = frame->tf_err; 665 666 #if 0 667 kernel_trap: 668 #endif 669 /* kernel trap */ 670 671 switch (type) { 672 case T_PAGEFLT: /* page fault */ 673 MAKEMPSAFE(have_mplock); 674 trap_pfault(frame, FALSE, eva); 675 goto out2; 676 677 case T_DNA: 678 /* 679 * The kernel may be using npx for copying or other 680 * purposes. 681 */ 682 panic("kernel NPX should not happen"); 683 if (npxdna(frame)) 684 goto out2; 685 break; 686 687 case T_PROTFLT: /* general protection fault */ 688 case T_SEGNPFLT: /* segment not present fault */ 689 /* 690 * Invalid segment selectors and out of bounds 691 * %eip's and %esp's can be set up in user mode. 692 * This causes a fault in kernel mode when the 693 * kernel tries to return to user mode. We want 694 * to get this fault so that we can fix the 695 * problem here and not have to check all the 696 * selectors and pointers when the user changes 697 * them. 698 */ 699 if (mycpu->gd_intr_nesting_level == 0) { 700 if (td->td_pcb->pcb_onfault) { 701 frame->tf_rip = 702 (register_t)td->td_pcb->pcb_onfault; 703 goto out2; 704 } 705 } 706 break; 707 708 case T_TSSFLT: 709 /* 710 * PSL_NT can be set in user mode and isn't cleared 711 * automatically when the kernel is entered. This 712 * causes a TSS fault when the kernel attempts to 713 * `iret' because the TSS link is uninitialized. We 714 * want to get this fault so that we can fix the 715 * problem here and not every time the kernel is 716 * entered. 717 */ 718 if (frame->tf_rflags & PSL_NT) { 719 frame->tf_rflags &= ~PSL_NT; 720 goto out2; 721 } 722 break; 723 724 case T_TRCTRAP: /* trace trap */ 725 #if 0 726 if (frame->tf_eip == (int)IDTVEC(syscall)) { 727 /* 728 * We've just entered system mode via the 729 * syscall lcall. Continue single stepping 730 * silently until the syscall handler has 731 * saved the flags. 732 */ 733 goto out2; 734 } 735 if (frame->tf_eip == (int)IDTVEC(syscall) + 1) { 736 /* 737 * The syscall handler has now saved the 738 * flags. Stop single stepping it. 739 */ 740 frame->tf_eflags &= ~PSL_T; 741 goto out2; 742 } 743 #endif 744 #if 0 745 /* 746 * Ignore debug register trace traps due to 747 * accesses in the user's address space, which 748 * can happen under several conditions such as 749 * if a user sets a watchpoint on a buffer and 750 * then passes that buffer to a system call. 751 * We still want to get TRCTRAPS for addresses 752 * in kernel space because that is useful when 753 * debugging the kernel. 754 */ 755 if (user_dbreg_trap()) { 756 /* 757 * Reset breakpoint bits because the 758 * processor doesn't 759 */ 760 load_dr6(rdr6() & 0xfffffff0); 761 goto out2; 762 } 763 #endif 764 /* 765 * Fall through (TRCTRAP kernel mode, kernel address) 766 */ 767 case T_BPTFLT: 768 /* 769 * If DDB is enabled, let it handle the debugger trap. 770 * Otherwise, debugger traps "can't happen". 771 */ 772 #ifdef DDB 773 MAKEMPSAFE(have_mplock); 774 if (kdb_trap (type, 0, frame)) 775 goto out2; 776 #endif 777 break; 778 case T_DIVIDE: 779 MAKEMPSAFE(have_mplock); 780 trap_fatal(frame, FALSE, eva); 781 goto out2; 782 case T_NMI: 783 MAKEMPSAFE(have_mplock); 784 trap_fatal(frame, FALSE, eva); 785 goto out2; 786 case T_SYSCALL80: 787 case T_FAST_SYSCALL: 788 /* 789 * Ignore this trap generated from a spurious SIGTRAP. 790 * 791 * single stepping in / syscalls leads to spurious / SIGTRAP 792 * so ignore 793 * 794 * Haiku (c) 2007 Simon 'corecode' Schubert 795 */ 796 goto out2; 797 } 798 799 /* 800 * Translate fault for emulators (e.g. Linux) 801 */ 802 if (*p->p_sysent->sv_transtrap) 803 i = (*p->p_sysent->sv_transtrap)(i, type); 804 805 MAKEMPSAFE(have_mplock); 806 trapsignal(lp, i, ucode); 807 808 #ifdef DEBUG 809 if (type <= MAX_TRAP_MSG) { 810 uprintf("fatal process exception: %s", 811 trap_msg[type]); 812 if ((type == T_PAGEFLT) || (type == T_PROTFLT)) 813 uprintf(", fault VA = 0x%lx", (u_long)eva); 814 uprintf("\n"); 815 } 816 #endif 817 818 out2: 819 ; 820 #ifdef SMP 821 if (have_mplock) 822 rel_mplock(); 823 #endif 824 #ifdef INVARIANTS 825 KASSERT(crit_count == td->td_critcount, 826 ("trap: critical section count mismatch! %d/%d", 827 crit_count, td->td_pri)); 828 KASSERT(curstop == td->td_toks_stop, 829 ("trap: extra tokens held after trap! %ld/%ld", 830 curstop - &td->td_toks_base, 831 td->td_toks_stop - &td->td_toks_base)); 832 #endif 833 } 834 835 int 836 trap_pfault(struct trapframe *frame, int usermode, vm_offset_t eva) 837 { 838 vm_offset_t va; 839 struct vmspace *vm = NULL; 840 vm_map_t map = 0; 841 int rv = 0; 842 vm_prot_t ftype; 843 thread_t td = curthread; 844 struct lwp *lp = td->td_lwp; 845 846 va = trunc_page(eva); 847 if (usermode == FALSE) { 848 /* 849 * This is a fault on kernel virtual memory. 850 */ 851 map = &kernel_map; 852 } else { 853 /* 854 * This is a fault on non-kernel virtual memory. 855 * vm is initialized above to NULL. If curproc is NULL 856 * or curproc->p_vmspace is NULL the fault is fatal. 857 */ 858 if (lp != NULL) 859 vm = lp->lwp_vmspace; 860 861 if (vm == NULL) 862 goto nogo; 863 864 map = &vm->vm_map; 865 } 866 867 if (frame->tf_err & PGEX_W) 868 ftype = VM_PROT_READ | VM_PROT_WRITE; 869 else 870 ftype = VM_PROT_READ; 871 872 if (map != &kernel_map) { 873 /* 874 * Keep swapout from messing with us during this 875 * critical time. 876 */ 877 PHOLD(lp->lwp_proc); 878 879 /* 880 * Grow the stack if necessary 881 */ 882 /* grow_stack returns false only if va falls into 883 * a growable stack region and the stack growth 884 * fails. It returns true if va was not within 885 * a growable stack region, or if the stack 886 * growth succeeded. 887 */ 888 if (!grow_stack (lp->lwp_proc, va)) { 889 rv = KERN_FAILURE; 890 PRELE(lp->lwp_proc); 891 goto nogo; 892 } 893 894 /* Fault in the user page: */ 895 rv = vm_fault(map, va, ftype, 896 (ftype & VM_PROT_WRITE) ? VM_FAULT_DIRTY 897 : VM_FAULT_NORMAL); 898 899 PRELE(lp->lwp_proc); 900 } else { 901 /* 902 * Don't have to worry about process locking or stacks in the kernel. 903 */ 904 rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL); 905 } 906 907 if (rv == KERN_SUCCESS) 908 return (0); 909 nogo: 910 if (!usermode) { 911 if (td->td_gd->gd_intr_nesting_level == 0 && 912 td->td_pcb->pcb_onfault) { 913 frame->tf_rip = (register_t)td->td_pcb->pcb_onfault; 914 return (0); 915 } 916 trap_fatal(frame, usermode, eva); 917 return (-1); 918 } 919 920 /* 921 * NOTE: on x86_64 we have a tf_addr field in the trapframe, no 922 * kludge is needed to pass the fault address to signal handlers. 923 */ 924 struct proc *p = td->td_proc; 925 kprintf("seg-fault accessing address %p rip=%p pid=%d p_comm=%s\n", 926 (void *)va, (void *)frame->tf_rip, p->p_pid, p->p_comm); 927 /* Debugger("seg-fault"); */ 928 929 return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV); 930 } 931 932 static void 933 trap_fatal(struct trapframe *frame, int usermode, vm_offset_t eva) 934 { 935 int code, type, ss; 936 long rsp; 937 938 code = frame->tf_xflags; 939 type = frame->tf_trapno; 940 941 if (type <= MAX_TRAP_MSG) { 942 kprintf("\n\nFatal trap %d: %s while in %s mode\n", 943 type, trap_msg[type], 944 (usermode ? "user" : "kernel")); 945 } 946 #ifdef SMP 947 /* two separate prints in case of a trap on an unmapped page */ 948 kprintf("cpuid = %d\n", mycpu->gd_cpuid); 949 #endif 950 if (type == T_PAGEFLT) { 951 kprintf("fault virtual address = %p\n", (void *)eva); 952 kprintf("fault code = %s %s, %s\n", 953 usermode ? "user" : "supervisor", 954 code & PGEX_W ? "write" : "read", 955 code & PGEX_P ? "protection violation" : "page not present"); 956 } 957 kprintf("instruction pointer = 0x%lx:0x%lx\n", 958 frame->tf_cs & 0xffff, frame->tf_rip); 959 if (usermode) { 960 ss = frame->tf_ss & 0xffff; 961 rsp = frame->tf_rsp; 962 } else { 963 ss = GSEL(GDATA_SEL, SEL_KPL); 964 rsp = (long)&frame->tf_rsp; 965 } 966 kprintf("stack pointer = 0x%x:0x%lx\n", ss, rsp); 967 kprintf("frame pointer = 0x%x:0x%lx\n", ss, frame->tf_rbp); 968 kprintf("processor eflags = "); 969 if (frame->tf_rflags & PSL_T) 970 kprintf("trace trap, "); 971 if (frame->tf_rflags & PSL_I) 972 kprintf("interrupt enabled, "); 973 if (frame->tf_rflags & PSL_NT) 974 kprintf("nested task, "); 975 if (frame->tf_rflags & PSL_RF) 976 kprintf("resume, "); 977 #if 0 978 if (frame->tf_eflags & PSL_VM) 979 kprintf("vm86, "); 980 #endif 981 kprintf("IOPL = %jd\n", (intmax_t)((frame->tf_rflags & PSL_IOPL) >> 12)); 982 kprintf("current process = "); 983 if (curproc) { 984 kprintf("%lu (%s)\n", 985 (u_long)curproc->p_pid, curproc->p_comm ? 986 curproc->p_comm : ""); 987 } else { 988 kprintf("Idle\n"); 989 } 990 kprintf("current thread = pri %d ", curthread->td_pri); 991 if (curthread->td_critcount) 992 kprintf("(CRIT)"); 993 kprintf("\n"); 994 #ifdef SMP 995 /** 996 * XXX FIXME: 997 * we probably SHOULD have stopped the other CPUs before now! 998 * another CPU COULD have been touching cpl at this moment... 999 */ 1000 kprintf(" <- SMP: XXX"); 1001 #endif 1002 kprintf("\n"); 1003 1004 #ifdef KDB 1005 if (kdb_trap(&psl)) 1006 return; 1007 #endif 1008 #ifdef DDB 1009 if ((debugger_on_panic || db_active) && kdb_trap(type, code, frame)) 1010 return; 1011 #endif 1012 kprintf("trap number = %d\n", type); 1013 if (type <= MAX_TRAP_MSG) 1014 panic("%s", trap_msg[type]); 1015 else 1016 panic("unknown/reserved trap"); 1017 } 1018 1019 /* 1020 * Double fault handler. Called when a fault occurs while writing 1021 * a frame for a trap/exception onto the stack. This usually occurs 1022 * when the stack overflows (such is the case with infinite recursion, 1023 * for example). 1024 * 1025 * XXX Note that the current PTD gets replaced by IdlePTD when the 1026 * task switch occurs. This means that the stack that was active at 1027 * the time of the double fault is not available at <kstack> unless 1028 * the machine was idle when the double fault occurred. The downside 1029 * of this is that "trace <ebp>" in ddb won't work. 1030 */ 1031 void 1032 dblfault_handler(void) 1033 { 1034 #if JG 1035 struct mdglobaldata *gd = mdcpu; 1036 #endif 1037 1038 kprintf("\nFatal double fault:\n"); 1039 #if JG 1040 kprintf("rip = 0x%lx\n", gd->gd_common_tss.tss_rip); 1041 kprintf("rsp = 0x%lx\n", gd->gd_common_tss.tss_rsp); 1042 kprintf("rbp = 0x%lx\n", gd->gd_common_tss.tss_rbp); 1043 #endif 1044 #ifdef SMP 1045 /* two separate prints in case of a trap on an unmapped page */ 1046 kprintf("cpuid = %d\n", mycpu->gd_cpuid); 1047 #endif 1048 panic("double fault"); 1049 } 1050 1051 /* 1052 * Compensate for 386 brain damage (missing URKR). 1053 * This is a little simpler than the pagefault handler in trap() because 1054 * it the page tables have already been faulted in and high addresses 1055 * are thrown out early for other reasons. 1056 */ 1057 int 1058 trapwrite(unsigned addr) 1059 { 1060 struct lwp *lp; 1061 vm_offset_t va; 1062 struct vmspace *vm; 1063 int rv; 1064 1065 va = trunc_page((vm_offset_t)addr); 1066 /* 1067 * XXX - MAX is END. Changed > to >= for temp. fix. 1068 */ 1069 if (va >= VM_MAX_USER_ADDRESS) 1070 return (1); 1071 1072 lp = curthread->td_lwp; 1073 vm = lp->lwp_vmspace; 1074 1075 PHOLD(lp->lwp_proc); 1076 1077 if (!grow_stack (lp->lwp_proc, va)) { 1078 PRELE(lp->lwp_proc); 1079 return (1); 1080 } 1081 1082 /* 1083 * fault the data page 1084 */ 1085 rv = vm_fault(&vm->vm_map, va, VM_PROT_WRITE, VM_FAULT_DIRTY); 1086 1087 PRELE(lp->lwp_proc); 1088 1089 if (rv != KERN_SUCCESS) 1090 return 1; 1091 1092 return (0); 1093 } 1094 1095 /* 1096 * syscall2 - MP aware system call request C handler 1097 * 1098 * A system call is essentially treated as a trap except that the 1099 * MP lock is not held on entry or return. We are responsible for 1100 * obtaining the MP lock if necessary and for handling ASTs 1101 * (e.g. a task switch) prior to return. 1102 * 1103 * In general, only simple access and manipulation of curproc and 1104 * the current stack is allowed without having to hold MP lock. 1105 * 1106 * MPSAFE - note that large sections of this routine are run without 1107 * the MP lock. 1108 */ 1109 void 1110 syscall2(struct trapframe *frame) 1111 { 1112 struct thread *td = curthread; 1113 struct proc *p = td->td_proc; 1114 struct lwp *lp = td->td_lwp; 1115 caddr_t params; 1116 struct sysent *callp; 1117 register_t orig_tf_rflags; 1118 int sticks; 1119 int error; 1120 int narg; 1121 #ifdef INVARIANTS 1122 int crit_count = td->td_critcount; 1123 lwkt_tokref_t curstop = td->td_toks_stop; 1124 #endif 1125 #ifdef SMP 1126 int have_mplock = 0; 1127 #endif 1128 register_t *argp; 1129 u_int code; 1130 int reg, regcnt; 1131 union sysunion args; 1132 register_t *argsdst; 1133 1134 mycpu->gd_cnt.v_syscall++; 1135 1136 KTR_LOG(kernentry_syscall, lp->lwp_proc->p_pid, lp->lwp_tid, 1137 frame->tf_eax); 1138 1139 userenter(td, p); /* lazy raise our priority */ 1140 1141 reg = 0; 1142 regcnt = 6; 1143 /* 1144 * Misc 1145 */ 1146 sticks = (int)td->td_sticks; 1147 orig_tf_rflags = frame->tf_rflags; 1148 1149 /* 1150 * Virtual kernel intercept - if a VM context managed by a virtual 1151 * kernel issues a system call the virtual kernel handles it, not us. 1152 * Restore the virtual kernel context and return from its system 1153 * call. The current frame is copied out to the virtual kernel. 1154 */ 1155 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) { 1156 vkernel_trap(lp, frame); 1157 error = EJUSTRETURN; 1158 goto out; 1159 } 1160 1161 /* 1162 * Get the system call parameters and account for time 1163 */ 1164 lp->lwp_md.md_regs = frame; 1165 params = (caddr_t)frame->tf_rsp + sizeof(register_t); 1166 code = frame->tf_rax; 1167 1168 if (p->p_sysent->sv_prepsyscall) { 1169 (*p->p_sysent->sv_prepsyscall)( 1170 frame, (int *)(&args.nosys.sysmsg + 1), 1171 &code, ¶ms); 1172 } else { 1173 if (code == SYS_syscall || code == SYS___syscall) { 1174 code = frame->tf_rdi; 1175 reg++; 1176 regcnt--; 1177 } 1178 } 1179 1180 if (p->p_sysent->sv_mask) 1181 code &= p->p_sysent->sv_mask; 1182 1183 if (code >= p->p_sysent->sv_size) 1184 callp = &p->p_sysent->sv_table[0]; 1185 else 1186 callp = &p->p_sysent->sv_table[code]; 1187 1188 narg = callp->sy_narg & SYF_ARGMASK; 1189 1190 /* 1191 * On x86_64 we get up to six arguments in registers. The rest are 1192 * on the stack. The first six members of 'struct trapframe' happen 1193 * to be the registers used to pass arguments, in exactly the right 1194 * order. 1195 */ 1196 argp = &frame->tf_rdi; 1197 argp += reg; 1198 argsdst = (register_t *)(&args.nosys.sysmsg + 1); 1199 /* 1200 * JG can we overflow the space pointed to by 'argsdst' 1201 * either with 'bcopy' or with 'copyin'? 1202 */ 1203 bcopy(argp, argsdst, sizeof(register_t) * regcnt); 1204 /* 1205 * copyin is MP aware, but the tracing code is not 1206 */ 1207 if (narg > regcnt) { 1208 KASSERT(params != NULL, ("copyin args with no params!")); 1209 error = copyin(params, &argsdst[regcnt], 1210 (narg - regcnt) * sizeof(register_t)); 1211 if (error) { 1212 #ifdef KTRACE 1213 if (KTRPOINT(td, KTR_SYSCALL)) { 1214 MAKEMPSAFE(have_mplock); 1215 1216 ktrsyscall(lp, code, narg, 1217 (void *)(&args.nosys.sysmsg + 1)); 1218 } 1219 #endif 1220 goto bad; 1221 } 1222 } 1223 1224 #ifdef KTRACE 1225 if (KTRPOINT(td, KTR_SYSCALL)) { 1226 MAKEMPSAFE(have_mplock); 1227 ktrsyscall(lp, code, narg, (void *)(&args.nosys.sysmsg + 1)); 1228 } 1229 #endif 1230 1231 /* 1232 * Default return value is 0 (will be copied to %rax). Double-value 1233 * returns use %rax and %rdx. %rdx is left unchanged for system 1234 * calls which return only one result. 1235 */ 1236 args.sysmsg_fds[0] = 0; 1237 args.sysmsg_fds[1] = frame->tf_rdx; 1238 1239 /* 1240 * The syscall might manipulate the trap frame. If it does it 1241 * will probably return EJUSTRETURN. 1242 */ 1243 args.sysmsg_frame = frame; 1244 1245 STOPEVENT(p, S_SCE, narg); /* MP aware */ 1246 1247 /* 1248 * NOTE: All system calls run MPSAFE now. The system call itself 1249 * is responsible for getting the MP lock. 1250 */ 1251 error = (*callp->sy_call)(&args); 1252 1253 #if 0 1254 kprintf("system call %d returned %d\n", code, error); 1255 #endif 1256 1257 out: 1258 /* 1259 * MP SAFE (we may or may not have the MP lock at this point) 1260 */ 1261 switch (error) { 1262 case 0: 1263 /* 1264 * Reinitialize proc pointer `p' as it may be different 1265 * if this is a child returning from fork syscall. 1266 */ 1267 p = curproc; 1268 lp = curthread->td_lwp; 1269 frame->tf_rax = args.sysmsg_fds[0]; 1270 frame->tf_rdx = args.sysmsg_fds[1]; 1271 frame->tf_rflags &= ~PSL_C; 1272 break; 1273 case ERESTART: 1274 /* 1275 * Reconstruct pc, we know that 'syscall' is 2 bytes. 1276 * We have to do a full context restore so that %r10 1277 * (which was holding the value of %rcx) is restored for 1278 * the next iteration. 1279 */ 1280 frame->tf_rip -= frame->tf_err; 1281 frame->tf_r10 = frame->tf_rcx; 1282 break; 1283 case EJUSTRETURN: 1284 break; 1285 case EASYNC: 1286 panic("Unexpected EASYNC return value (for now)"); 1287 default: 1288 bad: 1289 if (p->p_sysent->sv_errsize) { 1290 if (error >= p->p_sysent->sv_errsize) 1291 error = -1; /* XXX */ 1292 else 1293 error = p->p_sysent->sv_errtbl[error]; 1294 } 1295 frame->tf_rax = error; 1296 frame->tf_rflags |= PSL_C; 1297 break; 1298 } 1299 1300 /* 1301 * Traced syscall. trapsignal() is not MP aware. 1302 */ 1303 if (orig_tf_rflags & PSL_T) { 1304 MAKEMPSAFE(have_mplock); 1305 frame->tf_rflags &= ~PSL_T; 1306 trapsignal(lp, SIGTRAP, 0); 1307 } 1308 1309 /* 1310 * Handle reschedule and other end-of-syscall issues 1311 */ 1312 userret(lp, frame, sticks); 1313 1314 #ifdef KTRACE 1315 if (KTRPOINT(td, KTR_SYSRET)) { 1316 MAKEMPSAFE(have_mplock); 1317 ktrsysret(lp, code, error, args.sysmsg_result); 1318 } 1319 #endif 1320 1321 /* 1322 * This works because errno is findable through the 1323 * register set. If we ever support an emulation where this 1324 * is not the case, this code will need to be revisited. 1325 */ 1326 STOPEVENT(p, S_SCX, code); 1327 1328 userexit(lp); 1329 #ifdef SMP 1330 /* 1331 * Release the MP lock if we had to get it 1332 */ 1333 if (have_mplock) 1334 rel_mplock(); 1335 #endif 1336 KTR_LOG(kernentry_syscall_ret, lp->lwp_proc->p_pid, lp->lwp_tid, error); 1337 #ifdef INVARIANTS 1338 KASSERT(&td->td_toks_base == td->td_toks_stop, 1339 ("syscall: critical section count mismatch! %d/%d", 1340 crit_count, td->td_pri)); 1341 KASSERT(curstop == td->td_toks_stop, 1342 ("syscall: extra tokens held after trap! %ld", 1343 td->td_toks_stop - &td->td_toks_base)); 1344 #endif 1345 } 1346 1347 /* 1348 * NOTE: mplock not held at any point 1349 */ 1350 void 1351 fork_return(struct lwp *lp, struct trapframe *frame) 1352 { 1353 frame->tf_rax = 0; /* Child returns zero */ 1354 frame->tf_rflags &= ~PSL_C; /* success */ 1355 frame->tf_rdx = 1; 1356 1357 generic_lwp_return(lp, frame); 1358 KTR_LOG(kernentry_fork_ret, lp->lwp_proc->p_pid, lp->lwp_tid); 1359 } 1360 1361 /* 1362 * Simplified back end of syscall(), used when returning from fork() 1363 * directly into user mode. 1364 * 1365 * This code will return back into the fork trampoline code which then 1366 * runs doreti. 1367 * 1368 * NOTE: The mplock is not held at any point. 1369 */ 1370 void 1371 generic_lwp_return(struct lwp *lp, struct trapframe *frame) 1372 { 1373 struct proc *p = lp->lwp_proc; 1374 1375 /* 1376 * Newly forked processes are given a kernel priority. We have to 1377 * adjust the priority to a normal user priority and fake entry 1378 * into the kernel (call userenter()) to install a passive release 1379 * function just in case userret() decides to stop the process. This 1380 * can occur when ^Z races a fork. If we do not install the passive 1381 * release function the current process designation will not be 1382 * released when the thread goes to sleep. 1383 */ 1384 lwkt_setpri_self(TDPRI_USER_NORM); 1385 userenter(lp->lwp_thread, p); 1386 userret(lp, frame, 0); 1387 #ifdef KTRACE 1388 if (KTRPOINT(lp->lwp_thread, KTR_SYSRET)) 1389 ktrsysret(lp, SYS_fork, 0, 0); 1390 #endif 1391 p->p_flag |= P_PASSIVE_ACQ; 1392 userexit(lp); 1393 p->p_flag &= ~P_PASSIVE_ACQ; 1394 } 1395 1396 /* 1397 * doreti has turned into this. The frame is directly on the stack. We 1398 * pull everything else we need (fpu and tls context) from the current 1399 * thread. 1400 * 1401 * Note on fpu interactions: In a virtual kernel, the fpu context for 1402 * an emulated user mode process is not shared with the virtual kernel's 1403 * fpu context, so we only have to 'stack' fpu contexts within the virtual 1404 * kernel itself, and not even then since the signal() contexts that we care 1405 * about save and restore the FPU state (I think anyhow). 1406 * 1407 * vmspace_ctl() returns an error only if it had problems instaling the 1408 * context we supplied or problems copying data to/from our VM space. 1409 */ 1410 void 1411 go_user(struct intrframe *frame) 1412 { 1413 struct trapframe *tf = (void *)&frame->if_rdi; 1414 int r; 1415 1416 /* 1417 * Interrupts may be disabled on entry, make sure all signals 1418 * can be received before beginning our loop. 1419 */ 1420 sigsetmask(0); 1421 1422 /* 1423 * Switch to the current simulated user process, then call 1424 * user_trap() when we break out of it (usually due to a signal). 1425 */ 1426 for (;;) { 1427 /* 1428 * Tell the real kernel whether it is ok to use the FP 1429 * unit or not. 1430 */ 1431 if (mdcpu->gd_npxthread == curthread) { 1432 tf->tf_xflags &= ~PGEX_FPFAULT; 1433 } else { 1434 tf->tf_xflags |= PGEX_FPFAULT; 1435 } 1436 1437 /* 1438 * Run emulated user process context. This call interlocks 1439 * with new mailbox signals. 1440 * 1441 * Set PGEX_U unconditionally, indicating a user frame (the 1442 * bit is normally set only by T_PAGEFLT). 1443 */ 1444 r = vmspace_ctl(&curproc->p_vmspace->vm_pmap, VMSPACE_CTL_RUN, 1445 tf, &curthread->td_savevext); 1446 frame->if_xflags |= PGEX_U; 1447 #if 0 1448 kprintf("GO USER %d trap %ld EVA %08lx RIP %08lx RSP %08lx XFLAGS %02lx/%02lx\n", 1449 r, tf->tf_trapno, tf->tf_addr, tf->tf_rip, tf->tf_rsp, 1450 tf->tf_xflags, frame->if_xflags); 1451 #endif 1452 if (r < 0) { 1453 if (errno != EINTR) 1454 panic("vmspace_ctl failed error %d", errno); 1455 } else { 1456 if (tf->tf_trapno) { 1457 user_trap(tf); 1458 } 1459 } 1460 if (mycpu->gd_reqflags & RQF_AST_MASK) { 1461 tf->tf_trapno = T_ASTFLT; 1462 user_trap(tf); 1463 } 1464 tf->tf_trapno = 0; 1465 } 1466 } 1467 1468 /* 1469 * If PGEX_FPFAULT is set then set FP_VIRTFP in the PCB to force a T_DNA 1470 * fault (which is then passed back to the virtual kernel) if an attempt is 1471 * made to use the FP unit. 1472 * 1473 * XXX this is a fairly big hack. 1474 */ 1475 void 1476 set_vkernel_fp(struct trapframe *frame) 1477 { 1478 struct thread *td = curthread; 1479 1480 if (frame->tf_xflags & PGEX_FPFAULT) { 1481 td->td_pcb->pcb_flags |= FP_VIRTFP; 1482 if (mdcpu->gd_npxthread == td) 1483 npxexit(); 1484 } else { 1485 td->td_pcb->pcb_flags &= ~FP_VIRTFP; 1486 } 1487 } 1488 1489 /* 1490 * Called from vkernel_trap() to fixup the vkernel's syscall 1491 * frame for vmspace_ctl() return. 1492 */ 1493 void 1494 cpu_vkernel_trap(struct trapframe *frame, int error) 1495 { 1496 frame->tf_rax = error; 1497 if (error) 1498 frame->tf_rflags |= PSL_C; 1499 else 1500 frame->tf_rflags &= ~PSL_C; 1501 } 1502