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_nonlocked(&mycpu->gd_reqflags, 447 RQF_AST_OWEUPC); 448 addupc_task(p, p->p_prof.pr_addr, 449 p->p_prof.pr_ticks); 450 } 451 goto out; 452 453 /* 454 * The following two traps can happen in 455 * vm86 mode, and, if so, we want to handle 456 * them specially. 457 */ 458 case T_PROTFLT: /* general protection fault */ 459 case T_STKFLT: /* stack fault */ 460 #if 0 461 if (frame->tf_eflags & PSL_VM) { 462 i = vm86_emulate((struct vm86frame *)frame); 463 if (i == 0) 464 goto out; 465 break; 466 } 467 #endif 468 /* FALL THROUGH */ 469 470 case T_SEGNPFLT: /* segment not present fault */ 471 case T_TSSFLT: /* invalid TSS fault */ 472 case T_DOUBLEFLT: /* double fault */ 473 default: 474 ucode = code + BUS_SEGM_FAULT ; 475 i = SIGBUS; 476 break; 477 478 case T_PAGEFLT: /* page fault */ 479 MAKEMPSAFE(have_mplock); 480 i = trap_pfault(frame, TRUE, eva); 481 if (i == -1) 482 goto out; 483 #if defined(I586_CPU) && !defined(NO_F00F_HACK) 484 if (i == -2) 485 goto restart; 486 #endif 487 if (i == 0) 488 goto out; 489 490 ucode = T_PAGEFLT; 491 break; 492 493 case T_DIVIDE: /* integer divide fault */ 494 ucode = FPE_INTDIV; 495 i = SIGFPE; 496 break; 497 498 #if NISA > 0 499 case T_NMI: 500 MAKEMPSAFE(have_mplock); 501 /* machine/parity/power fail/"kitchen sink" faults */ 502 if (isa_nmi(code) == 0) { 503 #ifdef DDB 504 /* 505 * NMI can be hooked up to a pushbutton 506 * for debugging. 507 */ 508 if (ddb_on_nmi) { 509 kprintf ("NMI ... going to debugger\n"); 510 kdb_trap (type, 0, frame); 511 } 512 #endif /* DDB */ 513 goto out2; 514 } else if (panic_on_nmi) 515 panic("NMI indicates hardware failure"); 516 break; 517 #endif /* NISA > 0 */ 518 519 case T_OFLOW: /* integer overflow fault */ 520 ucode = FPE_INTOVF; 521 i = SIGFPE; 522 break; 523 524 case T_BOUND: /* bounds check fault */ 525 ucode = FPE_FLTSUB; 526 i = SIGFPE; 527 break; 528 529 case T_DNA: 530 /* 531 * Virtual kernel intercept - pass the DNA exception 532 * to the (emulated) virtual kernel if it asked to handle 533 * it. This occurs when the virtual kernel is holding 534 * onto the FP context for a different emulated 535 * process then the one currently running. 536 * 537 * We must still call npxdna() since we may have 538 * saved FP state that the (emulated) virtual kernel 539 * needs to hand over to a different emulated process. 540 */ 541 if (lp->lwp_vkernel && lp->lwp_vkernel->ve && 542 (td->td_pcb->pcb_flags & FP_VIRTFP) 543 ) { 544 npxdna(frame); 545 break; 546 } 547 /* 548 * The kernel may have switched out the FP unit's 549 * state, causing the user process to take a fault 550 * when it tries to use the FP unit. Restore the 551 * state here 552 */ 553 if (npxdna(frame)) 554 goto out; 555 if (!pmath_emulate) { 556 i = SIGFPE; 557 ucode = FPE_FPU_NP_TRAP; 558 break; 559 } 560 i = (*pmath_emulate)(frame); 561 if (i == 0) { 562 if (!(frame->tf_rflags & PSL_T)) 563 goto out2; 564 frame->tf_rflags &= ~PSL_T; 565 i = SIGTRAP; 566 } 567 /* else ucode = emulator_only_knows() XXX */ 568 break; 569 570 case T_FPOPFLT: /* FPU operand fetch fault */ 571 ucode = T_FPOPFLT; 572 i = SIGILL; 573 break; 574 575 case T_XMMFLT: /* SIMD floating-point exception */ 576 ucode = 0; /* XXX */ 577 i = SIGFPE; 578 break; 579 } 580 581 /* 582 * Virtual kernel intercept - if the fault is directly related to a 583 * VM context managed by a virtual kernel then let the virtual kernel 584 * handle it. 585 */ 586 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) { 587 vkernel_trap(lp, frame); 588 goto out; 589 } 590 591 /* 592 * Translate fault for emulators (e.g. Linux) 593 */ 594 if (*p->p_sysent->sv_transtrap) 595 i = (*p->p_sysent->sv_transtrap)(i, type); 596 597 MAKEMPSAFE(have_mplock); 598 trapsignal(lp, i, ucode); 599 600 #ifdef DEBUG 601 if (type <= MAX_TRAP_MSG) { 602 uprintf("fatal process exception: %s", 603 trap_msg[type]); 604 if ((type == T_PAGEFLT) || (type == T_PROTFLT)) 605 uprintf(", fault VA = 0x%lx", (u_long)eva); 606 uprintf("\n"); 607 } 608 #endif 609 610 out: 611 #ifdef SMP 612 KASSERT(td->td_mpcount == have_mplock, 613 ("badmpcount trap/end from %p", (void *)frame->tf_rip)); 614 #endif 615 userret(lp, frame, sticks); 616 userexit(lp); 617 out2: ; 618 #ifdef SMP 619 if (have_mplock) 620 rel_mplock(); 621 #endif 622 KTR_LOG(kernentry_trap_ret, lp->lwp_proc->p_pid, lp->lwp_tid); 623 #ifdef INVARIANTS 624 KASSERT(crit_count == td->td_critcount, 625 ("trap: critical section count mismatch! %d/%d", 626 crit_count, td->td_pri)); 627 KASSERT(curstop == td->td_toks_stop, 628 ("trap: extra tokens held after trap! %ld/%ld", 629 curstop - &td->td_toks_base, 630 td->td_toks_stop - &td->td_toks_base)); 631 #endif 632 } 633 634 void 635 kern_trap(struct trapframe *frame) 636 { 637 struct globaldata *gd = mycpu; 638 struct thread *td = gd->gd_curthread; 639 struct lwp *lp; 640 struct proc *p; 641 int i = 0, ucode = 0, type, code; 642 #ifdef SMP 643 int have_mplock = 0; 644 #endif 645 #ifdef INVARIANTS 646 int crit_count = td->td_critcount; 647 lwkt_tokref_t curstop = td->td_toks_stop; 648 #endif 649 vm_offset_t eva; 650 651 lp = td->td_lwp; 652 p = td->td_proc; 653 654 if (frame->tf_trapno == T_PAGEFLT) 655 eva = frame->tf_addr; 656 else 657 eva = 0; 658 659 #ifdef DDB 660 if (db_active) { 661 ++gd->gd_trap_nesting_level; 662 MAKEMPSAFE(have_mplock); 663 trap_fatal(frame, FALSE, eva); 664 --gd->gd_trap_nesting_level; 665 goto out2; 666 } 667 #endif 668 669 type = frame->tf_trapno; 670 code = frame->tf_err; 671 672 #if 0 673 kernel_trap: 674 #endif 675 /* kernel trap */ 676 677 switch (type) { 678 case T_PAGEFLT: /* page fault */ 679 MAKEMPSAFE(have_mplock); 680 trap_pfault(frame, FALSE, eva); 681 goto out2; 682 683 case T_DNA: 684 /* 685 * The kernel may be using npx for copying or other 686 * purposes. 687 */ 688 panic("kernel NPX should not happen"); 689 if (npxdna(frame)) 690 goto out2; 691 break; 692 693 case T_PROTFLT: /* general protection fault */ 694 case T_SEGNPFLT: /* segment not present fault */ 695 /* 696 * Invalid segment selectors and out of bounds 697 * %eip's and %esp's can be set up in user mode. 698 * This causes a fault in kernel mode when the 699 * kernel tries to return to user mode. We want 700 * to get this fault so that we can fix the 701 * problem here and not have to check all the 702 * selectors and pointers when the user changes 703 * them. 704 */ 705 if (mycpu->gd_intr_nesting_level == 0) { 706 if (td->td_pcb->pcb_onfault) { 707 frame->tf_rip = 708 (register_t)td->td_pcb->pcb_onfault; 709 goto out2; 710 } 711 } 712 break; 713 714 case T_TSSFLT: 715 /* 716 * PSL_NT can be set in user mode and isn't cleared 717 * automatically when the kernel is entered. This 718 * causes a TSS fault when the kernel attempts to 719 * `iret' because the TSS link is uninitialized. We 720 * want to get this fault so that we can fix the 721 * problem here and not every time the kernel is 722 * entered. 723 */ 724 if (frame->tf_rflags & PSL_NT) { 725 frame->tf_rflags &= ~PSL_NT; 726 goto out2; 727 } 728 break; 729 730 case T_TRCTRAP: /* trace trap */ 731 #if 0 732 if (frame->tf_eip == (int)IDTVEC(syscall)) { 733 /* 734 * We've just entered system mode via the 735 * syscall lcall. Continue single stepping 736 * silently until the syscall handler has 737 * saved the flags. 738 */ 739 goto out2; 740 } 741 if (frame->tf_eip == (int)IDTVEC(syscall) + 1) { 742 /* 743 * The syscall handler has now saved the 744 * flags. Stop single stepping it. 745 */ 746 frame->tf_eflags &= ~PSL_T; 747 goto out2; 748 } 749 #endif 750 #if 0 751 /* 752 * Ignore debug register trace traps due to 753 * accesses in the user's address space, which 754 * can happen under several conditions such as 755 * if a user sets a watchpoint on a buffer and 756 * then passes that buffer to a system call. 757 * We still want to get TRCTRAPS for addresses 758 * in kernel space because that is useful when 759 * debugging the kernel. 760 */ 761 if (user_dbreg_trap()) { 762 /* 763 * Reset breakpoint bits because the 764 * processor doesn't 765 */ 766 load_dr6(rdr6() & 0xfffffff0); 767 goto out2; 768 } 769 #endif 770 /* 771 * Fall through (TRCTRAP kernel mode, kernel address) 772 */ 773 case T_BPTFLT: 774 /* 775 * If DDB is enabled, let it handle the debugger trap. 776 * Otherwise, debugger traps "can't happen". 777 */ 778 #ifdef DDB 779 MAKEMPSAFE(have_mplock); 780 if (kdb_trap (type, 0, frame)) 781 goto out2; 782 #endif 783 break; 784 case T_DIVIDE: 785 MAKEMPSAFE(have_mplock); 786 trap_fatal(frame, FALSE, eva); 787 goto out2; 788 case T_NMI: 789 MAKEMPSAFE(have_mplock); 790 trap_fatal(frame, FALSE, eva); 791 goto out2; 792 case T_SYSCALL80: 793 case T_FAST_SYSCALL: 794 /* 795 * Ignore this trap generated from a spurious SIGTRAP. 796 * 797 * single stepping in / syscalls leads to spurious / SIGTRAP 798 * so ignore 799 * 800 * Haiku (c) 2007 Simon 'corecode' Schubert 801 */ 802 goto out2; 803 } 804 805 /* 806 * Translate fault for emulators (e.g. Linux) 807 */ 808 if (*p->p_sysent->sv_transtrap) 809 i = (*p->p_sysent->sv_transtrap)(i, type); 810 811 MAKEMPSAFE(have_mplock); 812 trapsignal(lp, i, ucode); 813 814 #ifdef DEBUG 815 if (type <= MAX_TRAP_MSG) { 816 uprintf("fatal process exception: %s", 817 trap_msg[type]); 818 if ((type == T_PAGEFLT) || (type == T_PROTFLT)) 819 uprintf(", fault VA = 0x%lx", (u_long)eva); 820 uprintf("\n"); 821 } 822 #endif 823 824 out2: 825 ; 826 #ifdef SMP 827 if (have_mplock) 828 rel_mplock(); 829 #endif 830 #ifdef INVARIANTS 831 KASSERT(crit_count == td->td_critcount, 832 ("trap: critical section count mismatch! %d/%d", 833 crit_count, td->td_pri)); 834 KASSERT(curstop == td->td_toks_stop, 835 ("trap: extra tokens held after trap! %ld/%ld", 836 curstop - &td->td_toks_base, 837 td->td_toks_stop - &td->td_toks_base)); 838 #endif 839 } 840 841 int 842 trap_pfault(struct trapframe *frame, int usermode, vm_offset_t eva) 843 { 844 vm_offset_t va; 845 struct vmspace *vm = NULL; 846 vm_map_t map = 0; 847 int rv = 0; 848 vm_prot_t ftype; 849 thread_t td = curthread; 850 struct lwp *lp = td->td_lwp; 851 852 va = trunc_page(eva); 853 if (usermode == FALSE) { 854 /* 855 * This is a fault on kernel virtual memory. 856 */ 857 map = &kernel_map; 858 } else { 859 /* 860 * This is a fault on non-kernel virtual memory. 861 * vm is initialized above to NULL. If curproc is NULL 862 * or curproc->p_vmspace is NULL the fault is fatal. 863 */ 864 if (lp != NULL) 865 vm = lp->lwp_vmspace; 866 867 if (vm == NULL) 868 goto nogo; 869 870 map = &vm->vm_map; 871 } 872 873 if (frame->tf_err & PGEX_W) 874 ftype = VM_PROT_READ | VM_PROT_WRITE; 875 else 876 ftype = VM_PROT_READ; 877 878 if (map != &kernel_map) { 879 /* 880 * Keep swapout from messing with us during this 881 * critical time. 882 */ 883 PHOLD(lp->lwp_proc); 884 885 /* 886 * Grow the stack if necessary 887 */ 888 /* grow_stack returns false only if va falls into 889 * a growable stack region and the stack growth 890 * fails. It returns true if va was not within 891 * a growable stack region, or if the stack 892 * growth succeeded. 893 */ 894 if (!grow_stack (lp->lwp_proc, va)) { 895 rv = KERN_FAILURE; 896 PRELE(lp->lwp_proc); 897 goto nogo; 898 } 899 900 /* Fault in the user page: */ 901 rv = vm_fault(map, va, ftype, 902 (ftype & VM_PROT_WRITE) ? VM_FAULT_DIRTY 903 : VM_FAULT_NORMAL); 904 905 PRELE(lp->lwp_proc); 906 } else { 907 /* 908 * Don't have to worry about process locking or stacks in the kernel. 909 */ 910 rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL); 911 } 912 913 if (rv == KERN_SUCCESS) 914 return (0); 915 nogo: 916 if (!usermode) { 917 if (td->td_gd->gd_intr_nesting_level == 0 && 918 td->td_pcb->pcb_onfault) { 919 frame->tf_rip = (register_t)td->td_pcb->pcb_onfault; 920 return (0); 921 } 922 trap_fatal(frame, usermode, eva); 923 return (-1); 924 } 925 926 /* 927 * NOTE: on x86_64 we have a tf_addr field in the trapframe, no 928 * kludge is needed to pass the fault address to signal handlers. 929 */ 930 struct proc *p = td->td_proc; 931 kprintf("seg-fault accessing address %p rip=%p pid=%d p_comm=%s\n", 932 (void *)va, (void *)frame->tf_rip, p->p_pid, p->p_comm); 933 /* Debugger("seg-fault"); */ 934 935 return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV); 936 } 937 938 static void 939 trap_fatal(struct trapframe *frame, int usermode, vm_offset_t eva) 940 { 941 int code, type, ss; 942 long rsp; 943 944 code = frame->tf_xflags; 945 type = frame->tf_trapno; 946 947 if (type <= MAX_TRAP_MSG) { 948 kprintf("\n\nFatal trap %d: %s while in %s mode\n", 949 type, trap_msg[type], 950 (usermode ? "user" : "kernel")); 951 } 952 #ifdef SMP 953 /* two separate prints in case of a trap on an unmapped page */ 954 kprintf("mp_lock = %08x; ", mp_lock); 955 kprintf("cpuid = %d\n", mycpu->gd_cpuid); 956 #endif 957 if (type == T_PAGEFLT) { 958 kprintf("fault virtual address = %p\n", (void *)eva); 959 kprintf("fault code = %s %s, %s\n", 960 usermode ? "user" : "supervisor", 961 code & PGEX_W ? "write" : "read", 962 code & PGEX_P ? "protection violation" : "page not present"); 963 } 964 kprintf("instruction pointer = 0x%lx:0x%lx\n", 965 frame->tf_cs & 0xffff, frame->tf_rip); 966 if (usermode) { 967 ss = frame->tf_ss & 0xffff; 968 rsp = frame->tf_rsp; 969 } else { 970 ss = GSEL(GDATA_SEL, SEL_KPL); 971 rsp = (long)&frame->tf_rsp; 972 } 973 kprintf("stack pointer = 0x%x:0x%lx\n", ss, rsp); 974 kprintf("frame pointer = 0x%x:0x%lx\n", ss, frame->tf_rbp); 975 kprintf("processor eflags = "); 976 if (frame->tf_rflags & PSL_T) 977 kprintf("trace trap, "); 978 if (frame->tf_rflags & PSL_I) 979 kprintf("interrupt enabled, "); 980 if (frame->tf_rflags & PSL_NT) 981 kprintf("nested task, "); 982 if (frame->tf_rflags & PSL_RF) 983 kprintf("resume, "); 984 #if 0 985 if (frame->tf_eflags & PSL_VM) 986 kprintf("vm86, "); 987 #endif 988 kprintf("IOPL = %jd\n", (intmax_t)((frame->tf_rflags & PSL_IOPL) >> 12)); 989 kprintf("current process = "); 990 if (curproc) { 991 kprintf("%lu (%s)\n", 992 (u_long)curproc->p_pid, curproc->p_comm ? 993 curproc->p_comm : ""); 994 } else { 995 kprintf("Idle\n"); 996 } 997 kprintf("current thread = pri %d ", curthread->td_pri); 998 if (curthread->td_critcount) 999 kprintf("(CRIT)"); 1000 kprintf("\n"); 1001 #ifdef SMP 1002 /** 1003 * XXX FIXME: 1004 * we probably SHOULD have stopped the other CPUs before now! 1005 * another CPU COULD have been touching cpl at this moment... 1006 */ 1007 kprintf(" <- SMP: XXX"); 1008 #endif 1009 kprintf("\n"); 1010 1011 #ifdef KDB 1012 if (kdb_trap(&psl)) 1013 return; 1014 #endif 1015 #ifdef DDB 1016 if ((debugger_on_panic || db_active) && kdb_trap(type, code, frame)) 1017 return; 1018 #endif 1019 kprintf("trap number = %d\n", type); 1020 if (type <= MAX_TRAP_MSG) 1021 panic("%s", trap_msg[type]); 1022 else 1023 panic("unknown/reserved trap"); 1024 } 1025 1026 /* 1027 * Double fault handler. Called when a fault occurs while writing 1028 * a frame for a trap/exception onto the stack. This usually occurs 1029 * when the stack overflows (such is the case with infinite recursion, 1030 * for example). 1031 * 1032 * XXX Note that the current PTD gets replaced by IdlePTD when the 1033 * task switch occurs. This means that the stack that was active at 1034 * the time of the double fault is not available at <kstack> unless 1035 * the machine was idle when the double fault occurred. The downside 1036 * of this is that "trace <ebp>" in ddb won't work. 1037 */ 1038 void 1039 dblfault_handler(void) 1040 { 1041 #if JG 1042 struct mdglobaldata *gd = mdcpu; 1043 #endif 1044 1045 kprintf("\nFatal double fault:\n"); 1046 #if JG 1047 kprintf("rip = 0x%lx\n", gd->gd_common_tss.tss_rip); 1048 kprintf("rsp = 0x%lx\n", gd->gd_common_tss.tss_rsp); 1049 kprintf("rbp = 0x%lx\n", gd->gd_common_tss.tss_rbp); 1050 #endif 1051 #ifdef SMP 1052 /* two separate prints in case of a trap on an unmapped page */ 1053 kprintf("mp_lock = %08x; ", mp_lock); 1054 kprintf("cpuid = %d\n", mycpu->gd_cpuid); 1055 #endif 1056 panic("double fault"); 1057 } 1058 1059 /* 1060 * Compensate for 386 brain damage (missing URKR). 1061 * This is a little simpler than the pagefault handler in trap() because 1062 * it the page tables have already been faulted in and high addresses 1063 * are thrown out early for other reasons. 1064 */ 1065 int 1066 trapwrite(unsigned addr) 1067 { 1068 struct lwp *lp; 1069 vm_offset_t va; 1070 struct vmspace *vm; 1071 int rv; 1072 1073 va = trunc_page((vm_offset_t)addr); 1074 /* 1075 * XXX - MAX is END. Changed > to >= for temp. fix. 1076 */ 1077 if (va >= VM_MAX_USER_ADDRESS) 1078 return (1); 1079 1080 lp = curthread->td_lwp; 1081 vm = lp->lwp_vmspace; 1082 1083 PHOLD(lp->lwp_proc); 1084 1085 if (!grow_stack (lp->lwp_proc, va)) { 1086 PRELE(lp->lwp_proc); 1087 return (1); 1088 } 1089 1090 /* 1091 * fault the data page 1092 */ 1093 rv = vm_fault(&vm->vm_map, va, VM_PROT_WRITE, VM_FAULT_DIRTY); 1094 1095 PRELE(lp->lwp_proc); 1096 1097 if (rv != KERN_SUCCESS) 1098 return 1; 1099 1100 return (0); 1101 } 1102 1103 /* 1104 * syscall2 - MP aware system call request C handler 1105 * 1106 * A system call is essentially treated as a trap except that the 1107 * MP lock is not held on entry or return. We are responsible for 1108 * obtaining the MP lock if necessary and for handling ASTs 1109 * (e.g. a task switch) prior to return. 1110 * 1111 * In general, only simple access and manipulation of curproc and 1112 * the current stack is allowed without having to hold MP lock. 1113 * 1114 * MPSAFE - note that large sections of this routine are run without 1115 * the MP lock. 1116 */ 1117 void 1118 syscall2(struct trapframe *frame) 1119 { 1120 struct thread *td = curthread; 1121 struct proc *p = td->td_proc; 1122 struct lwp *lp = td->td_lwp; 1123 caddr_t params; 1124 struct sysent *callp; 1125 register_t orig_tf_rflags; 1126 int sticks; 1127 int error; 1128 int narg; 1129 #ifdef INVARIANTS 1130 int crit_count = td->td_critcount; 1131 lwkt_tokref_t curstop = td->td_toks_stop; 1132 #endif 1133 #ifdef SMP 1134 int have_mplock = 0; 1135 #endif 1136 register_t *argp; 1137 u_int code; 1138 int reg, regcnt; 1139 union sysunion args; 1140 register_t *argsdst; 1141 1142 mycpu->gd_cnt.v_syscall++; 1143 1144 KTR_LOG(kernentry_syscall, lp->lwp_proc->p_pid, lp->lwp_tid, 1145 frame->tf_eax); 1146 1147 #ifdef SMP 1148 KASSERT(td->td_mpcount == 0, 1149 ("badmpcount syscall2 from %p", (void *)frame->tf_rip)); 1150 #endif 1151 userenter(td, p); /* lazy raise our priority */ 1152 1153 reg = 0; 1154 regcnt = 6; 1155 /* 1156 * Misc 1157 */ 1158 sticks = (int)td->td_sticks; 1159 orig_tf_rflags = frame->tf_rflags; 1160 1161 /* 1162 * Virtual kernel intercept - if a VM context managed by a virtual 1163 * kernel issues a system call the virtual kernel handles it, not us. 1164 * Restore the virtual kernel context and return from its system 1165 * call. The current frame is copied out to the virtual kernel. 1166 */ 1167 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) { 1168 vkernel_trap(lp, frame); 1169 error = EJUSTRETURN; 1170 goto out; 1171 } 1172 1173 /* 1174 * Get the system call parameters and account for time 1175 */ 1176 lp->lwp_md.md_regs = frame; 1177 params = (caddr_t)frame->tf_rsp + sizeof(register_t); 1178 code = frame->tf_rax; 1179 1180 if (p->p_sysent->sv_prepsyscall) { 1181 (*p->p_sysent->sv_prepsyscall)( 1182 frame, (int *)(&args.nosys.sysmsg + 1), 1183 &code, ¶ms); 1184 } else { 1185 if (code == SYS_syscall || code == SYS___syscall) { 1186 code = frame->tf_rdi; 1187 reg++; 1188 regcnt--; 1189 } 1190 } 1191 1192 if (p->p_sysent->sv_mask) 1193 code &= p->p_sysent->sv_mask; 1194 1195 if (code >= p->p_sysent->sv_size) 1196 callp = &p->p_sysent->sv_table[0]; 1197 else 1198 callp = &p->p_sysent->sv_table[code]; 1199 1200 narg = callp->sy_narg & SYF_ARGMASK; 1201 1202 /* 1203 * On x86_64 we get up to six arguments in registers. The rest are 1204 * on the stack. The first six members of 'struct trapframe' happen 1205 * to be the registers used to pass arguments, in exactly the right 1206 * order. 1207 */ 1208 argp = &frame->tf_rdi; 1209 argp += reg; 1210 argsdst = (register_t *)(&args.nosys.sysmsg + 1); 1211 /* 1212 * JG can we overflow the space pointed to by 'argsdst' 1213 * either with 'bcopy' or with 'copyin'? 1214 */ 1215 bcopy(argp, argsdst, sizeof(register_t) * regcnt); 1216 /* 1217 * copyin is MP aware, but the tracing code is not 1218 */ 1219 if (narg > regcnt) { 1220 KASSERT(params != NULL, ("copyin args with no params!")); 1221 error = copyin(params, &argsdst[regcnt], 1222 (narg - regcnt) * sizeof(register_t)); 1223 if (error) { 1224 #ifdef KTRACE 1225 if (KTRPOINT(td, KTR_SYSCALL)) { 1226 MAKEMPSAFE(have_mplock); 1227 1228 ktrsyscall(lp, code, narg, 1229 (void *)(&args.nosys.sysmsg + 1)); 1230 } 1231 #endif 1232 goto bad; 1233 } 1234 } 1235 1236 #ifdef KTRACE 1237 if (KTRPOINT(td, KTR_SYSCALL)) { 1238 MAKEMPSAFE(have_mplock); 1239 ktrsyscall(lp, code, narg, (void *)(&args.nosys.sysmsg + 1)); 1240 } 1241 #endif 1242 1243 /* 1244 * Default return value is 0 (will be copied to %rax). Double-value 1245 * returns use %rax and %rdx. %rdx is left unchanged for system 1246 * calls which return only one result. 1247 */ 1248 args.sysmsg_fds[0] = 0; 1249 args.sysmsg_fds[1] = frame->tf_rdx; 1250 1251 /* 1252 * The syscall might manipulate the trap frame. If it does it 1253 * will probably return EJUSTRETURN. 1254 */ 1255 args.sysmsg_frame = frame; 1256 1257 STOPEVENT(p, S_SCE, narg); /* MP aware */ 1258 1259 /* 1260 * NOTE: All system calls run MPSAFE now. The system call itself 1261 * is responsible for getting the MP lock. 1262 */ 1263 error = (*callp->sy_call)(&args); 1264 1265 #if 0 1266 kprintf("system call %d returned %d\n", code, error); 1267 #endif 1268 1269 out: 1270 /* 1271 * MP SAFE (we may or may not have the MP lock at this point) 1272 */ 1273 switch (error) { 1274 case 0: 1275 /* 1276 * Reinitialize proc pointer `p' as it may be different 1277 * if this is a child returning from fork syscall. 1278 */ 1279 p = curproc; 1280 lp = curthread->td_lwp; 1281 frame->tf_rax = args.sysmsg_fds[0]; 1282 frame->tf_rdx = args.sysmsg_fds[1]; 1283 frame->tf_rflags &= ~PSL_C; 1284 break; 1285 case ERESTART: 1286 /* 1287 * Reconstruct pc, we know that 'syscall' is 2 bytes. 1288 * We have to do a full context restore so that %r10 1289 * (which was holding the value of %rcx) is restored for 1290 * the next iteration. 1291 */ 1292 frame->tf_rip -= frame->tf_err; 1293 frame->tf_r10 = frame->tf_rcx; 1294 break; 1295 case EJUSTRETURN: 1296 break; 1297 case EASYNC: 1298 panic("Unexpected EASYNC return value (for now)"); 1299 default: 1300 bad: 1301 if (p->p_sysent->sv_errsize) { 1302 if (error >= p->p_sysent->sv_errsize) 1303 error = -1; /* XXX */ 1304 else 1305 error = p->p_sysent->sv_errtbl[error]; 1306 } 1307 frame->tf_rax = error; 1308 frame->tf_rflags |= PSL_C; 1309 break; 1310 } 1311 1312 /* 1313 * Traced syscall. trapsignal() is not MP aware. 1314 */ 1315 if (orig_tf_rflags & PSL_T) { 1316 MAKEMPSAFE(have_mplock); 1317 frame->tf_rflags &= ~PSL_T; 1318 trapsignal(lp, SIGTRAP, 0); 1319 } 1320 1321 /* 1322 * Handle reschedule and other end-of-syscall issues 1323 */ 1324 userret(lp, frame, sticks); 1325 1326 #ifdef KTRACE 1327 if (KTRPOINT(td, KTR_SYSRET)) { 1328 MAKEMPSAFE(have_mplock); 1329 ktrsysret(lp, code, error, args.sysmsg_result); 1330 } 1331 #endif 1332 1333 /* 1334 * This works because errno is findable through the 1335 * register set. If we ever support an emulation where this 1336 * is not the case, this code will need to be revisited. 1337 */ 1338 STOPEVENT(p, S_SCX, code); 1339 1340 userexit(lp); 1341 #ifdef SMP 1342 /* 1343 * Release the MP lock if we had to get it 1344 */ 1345 KASSERT(td->td_mpcount == have_mplock, 1346 ("badmpcount syscall2/end from %p", (void *)frame->tf_rip)); 1347 if (have_mplock) 1348 rel_mplock(); 1349 #endif 1350 KTR_LOG(kernentry_syscall_ret, lp->lwp_proc->p_pid, lp->lwp_tid, error); 1351 #ifdef INVARIANTS 1352 KASSERT(&td->td_toks_base == td->td_toks_stop, 1353 ("syscall: critical section count mismatch! %d/%d", 1354 crit_count, td->td_pri)); 1355 KASSERT(curstop == td->td_toks_stop, 1356 ("syscall: extra tokens held after trap! %ld", 1357 td->td_toks_stop - &td->td_toks_base)); 1358 #endif 1359 } 1360 1361 /* 1362 * NOTE: mplock not held at any point 1363 */ 1364 void 1365 fork_return(struct lwp *lp, struct trapframe *frame) 1366 { 1367 frame->tf_rax = 0; /* Child returns zero */ 1368 frame->tf_rflags &= ~PSL_C; /* success */ 1369 frame->tf_rdx = 1; 1370 1371 generic_lwp_return(lp, frame); 1372 KTR_LOG(kernentry_fork_ret, lp->lwp_proc->p_pid, lp->lwp_tid); 1373 } 1374 1375 /* 1376 * Simplified back end of syscall(), used when returning from fork() 1377 * directly into user mode. 1378 * 1379 * This code will return back into the fork trampoline code which then 1380 * runs doreti. 1381 * 1382 * NOTE: The mplock is not held at any point. 1383 */ 1384 void 1385 generic_lwp_return(struct lwp *lp, struct trapframe *frame) 1386 { 1387 struct proc *p = lp->lwp_proc; 1388 1389 /* 1390 * Newly forked processes are given a kernel priority. We have to 1391 * adjust the priority to a normal user priority and fake entry 1392 * into the kernel (call userenter()) to install a passive release 1393 * function just in case userret() decides to stop the process. This 1394 * can occur when ^Z races a fork. If we do not install the passive 1395 * release function the current process designation will not be 1396 * released when the thread goes to sleep. 1397 */ 1398 lwkt_setpri_self(TDPRI_USER_NORM); 1399 userenter(lp->lwp_thread, p); 1400 userret(lp, frame, 0); 1401 #ifdef KTRACE 1402 if (KTRPOINT(lp->lwp_thread, KTR_SYSRET)) 1403 ktrsysret(lp, SYS_fork, 0, 0); 1404 #endif 1405 p->p_flag |= P_PASSIVE_ACQ; 1406 userexit(lp); 1407 p->p_flag &= ~P_PASSIVE_ACQ; 1408 } 1409 1410 /* 1411 * doreti has turned into this. The frame is directly on the stack. We 1412 * pull everything else we need (fpu and tls context) from the current 1413 * thread. 1414 * 1415 * Note on fpu interactions: In a virtual kernel, the fpu context for 1416 * an emulated user mode process is not shared with the virtual kernel's 1417 * fpu context, so we only have to 'stack' fpu contexts within the virtual 1418 * kernel itself, and not even then since the signal() contexts that we care 1419 * about save and restore the FPU state (I think anyhow). 1420 * 1421 * vmspace_ctl() returns an error only if it had problems instaling the 1422 * context we supplied or problems copying data to/from our VM space. 1423 */ 1424 void 1425 go_user(struct intrframe *frame) 1426 { 1427 struct trapframe *tf = (void *)&frame->if_rdi; 1428 int r; 1429 1430 /* 1431 * Interrupts may be disabled on entry, make sure all signals 1432 * can be received before beginning our loop. 1433 */ 1434 sigsetmask(0); 1435 1436 /* 1437 * Switch to the current simulated user process, then call 1438 * user_trap() when we break out of it (usually due to a signal). 1439 */ 1440 for (;;) { 1441 /* 1442 * Tell the real kernel whether it is ok to use the FP 1443 * unit or not. 1444 */ 1445 if (mdcpu->gd_npxthread == curthread) { 1446 tf->tf_xflags &= ~PGEX_FPFAULT; 1447 } else { 1448 tf->tf_xflags |= PGEX_FPFAULT; 1449 } 1450 1451 /* 1452 * Run emulated user process context. This call interlocks 1453 * with new mailbox signals. 1454 * 1455 * Set PGEX_U unconditionally, indicating a user frame (the 1456 * bit is normally set only by T_PAGEFLT). 1457 */ 1458 r = vmspace_ctl(&curproc->p_vmspace->vm_pmap, VMSPACE_CTL_RUN, 1459 tf, &curthread->td_savevext); 1460 frame->if_xflags |= PGEX_U; 1461 #if 0 1462 kprintf("GO USER %d trap %ld EVA %08lx RIP %08lx RSP %08lx XFLAGS %02lx/%02lx\n", 1463 r, tf->tf_trapno, tf->tf_addr, tf->tf_rip, tf->tf_rsp, 1464 tf->tf_xflags, frame->if_xflags); 1465 #endif 1466 if (r < 0) { 1467 if (errno != EINTR) 1468 panic("vmspace_ctl failed error %d", errno); 1469 } else { 1470 if (tf->tf_trapno) { 1471 user_trap(tf); 1472 } 1473 } 1474 if (mycpu->gd_reqflags & RQF_AST_MASK) { 1475 tf->tf_trapno = T_ASTFLT; 1476 user_trap(tf); 1477 } 1478 tf->tf_trapno = 0; 1479 } 1480 } 1481 1482 /* 1483 * If PGEX_FPFAULT is set then set FP_VIRTFP in the PCB to force a T_DNA 1484 * fault (which is then passed back to the virtual kernel) if an attempt is 1485 * made to use the FP unit. 1486 * 1487 * XXX this is a fairly big hack. 1488 */ 1489 void 1490 set_vkernel_fp(struct trapframe *frame) 1491 { 1492 struct thread *td = curthread; 1493 1494 if (frame->tf_xflags & PGEX_FPFAULT) { 1495 td->td_pcb->pcb_flags |= FP_VIRTFP; 1496 if (mdcpu->gd_npxthread == td) 1497 npxexit(); 1498 } else { 1499 td->td_pcb->pcb_flags &= ~FP_VIRTFP; 1500 } 1501 } 1502 1503 /* 1504 * Called from vkernel_trap() to fixup the vkernel's syscall 1505 * frame for vmspace_ctl() return. 1506 */ 1507 void 1508 cpu_vkernel_trap(struct trapframe *frame, int error) 1509 { 1510 frame->tf_rax = error; 1511 if (error) 1512 frame->tf_rflags |= PSL_C; 1513 else 1514 frame->tf_rflags &= ~PSL_C; 1515 } 1516