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_flags & 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_mpflags & LWP_MP_WEXIT) { 231 lwkt_gettoken(&p->p_token); 232 lwp_exit(0); 233 lwkt_reltoken(&p->p_token); /* NOT REACHED */ 234 } 235 236 /* 237 * Block here if we are in a stopped state. 238 */ 239 if (p->p_stat == SSTOP) { 240 lwkt_gettoken(&p->p_token); 241 tstop(); 242 lwkt_reltoken(&p->p_token); 243 goto recheck; 244 } 245 246 /* 247 * Post any pending upcalls. If running a virtual kernel be sure 248 * to restore the virtual kernel's vmspace before posting the upcall. 249 */ 250 if (p->p_flags & (P_SIGVTALRM | P_SIGPROF | P_UPCALLPEND)) { 251 lwkt_gettoken(&p->p_token); 252 if (p->p_flags & P_SIGVTALRM) { 253 p->p_flags &= ~P_SIGVTALRM; 254 ksignal(p, SIGVTALRM); 255 } 256 if (p->p_flags & P_SIGPROF) { 257 p->p_flags &= ~P_SIGPROF; 258 ksignal(p, SIGPROF); 259 } 260 if (p->p_flags & P_UPCALLPEND) { 261 p->p_flags &= ~P_UPCALLPEND; 262 postupcall(lp); 263 } 264 lwkt_reltoken(&p->p_token); 265 goto recheck; 266 } 267 268 /* 269 * Post any pending signals 270 * 271 * WARNING! postsig() can exit and not return. 272 */ 273 if ((sig = CURSIG_TRACE(lp)) != 0) { 274 lwkt_gettoken(&p->p_token); 275 postsig(sig); 276 lwkt_reltoken(&p->p_token); 277 goto recheck; 278 } 279 280 /* 281 * block here if we are swapped out, but still process signals 282 * (such as SIGKILL). proc0 (the swapin scheduler) is already 283 * aware of our situation, we do not have to wake it up. 284 */ 285 if (p->p_flags & P_SWAPPEDOUT) { 286 lwkt_gettoken(&p->p_token); 287 get_mplock(); 288 p->p_flags |= P_SWAPWAIT; 289 swapin_request(); 290 if (p->p_flags & P_SWAPWAIT) 291 tsleep(p, PCATCH, "SWOUT", 0); 292 p->p_flags &= ~P_SWAPWAIT; 293 rel_mplock(); 294 lwkt_reltoken(&p->p_token); 295 goto recheck; 296 } 297 298 /* 299 * Make sure postsig() handled request to restore old signal mask after 300 * running signal handler. 301 */ 302 KKASSERT((lp->lwp_flags & LWP_OLDMASK) == 0); 303 } 304 305 /* 306 * Cleanup from userenter and any passive release that might have occured. 307 * We must reclaim the current-process designation before we can return 308 * to usermode. We also handle both LWKT and USER reschedule requests. 309 */ 310 static __inline void 311 userexit(struct lwp *lp) 312 { 313 struct thread *td = lp->lwp_thread; 314 /* globaldata_t gd = td->td_gd; */ 315 316 /* 317 * Handle stop requests at kernel priority. Any requests queued 318 * after this loop will generate another AST. 319 */ 320 while (lp->lwp_proc->p_stat == SSTOP) { 321 lwkt_gettoken(&lp->lwp_proc->p_token); 322 tstop(); 323 lwkt_reltoken(&lp->lwp_proc->p_token); 324 } 325 326 /* 327 * Reduce our priority in preparation for a return to userland. If 328 * our passive release function was still in place, our priority was 329 * never raised and does not need to be reduced. 330 */ 331 lwkt_passive_recover(td); 332 333 /* 334 * Become the current user scheduled process if we aren't already, 335 * and deal with reschedule requests and other factors. 336 */ 337 lp->lwp_proc->p_usched->acquire_curproc(lp); 338 /* WARNING: we may have migrated cpu's */ 339 /* gd = td->td_gd; */ 340 } 341 342 #if !defined(KTR_KERNENTRY) 343 #define KTR_KERNENTRY KTR_ALL 344 #endif 345 KTR_INFO_MASTER(kernentry); 346 KTR_INFO(KTR_KERNENTRY, kernentry, trap, 0, 347 "TRAP(pid %hd, tid %hd, trapno %ld, eva %lu)", 348 pid_t pid, lwpid_t tid, register_t trapno, vm_offset_t eva); 349 KTR_INFO(KTR_KERNENTRY, kernentry, trap_ret, 0, "TRAP_RET(pid %hd, tid %hd)", 350 pid_t pid, lwpid_t tid); 351 KTR_INFO(KTR_KERNENTRY, kernentry, syscall, 0, "SYSC(pid %hd, tid %hd, nr %ld)", 352 pid_t pid, lwpid_t tid, register_t trapno); 353 KTR_INFO(KTR_KERNENTRY, kernentry, syscall_ret, 0, "SYSRET(pid %hd, tid %hd, err %d)", 354 pid_t pid, lwpid_t tid, int err); 355 KTR_INFO(KTR_KERNENTRY, kernentry, fork_ret, 0, "FORKRET(pid %hd, tid %hd)", 356 pid_t pid, lwpid_t tid); 357 358 /* 359 * Exception, fault, and trap interface to the kernel. 360 * This common code is called from assembly language IDT gate entry 361 * routines that prepare a suitable stack frame, and restore this 362 * frame after the exception has been processed. 363 * 364 * This function is also called from doreti in an interlock to handle ASTs. 365 * For example: hardwareint->INTROUTINE->(set ast)->doreti->trap 366 * 367 * NOTE! We have to retrieve the fault address prior to obtaining the 368 * MP lock because get_mplock() may switch out. YYY cr2 really ought 369 * to be retrieved by the assembly code, not here. 370 * 371 * XXX gd_trap_nesting_level currently prevents lwkt_switch() from panicing 372 * if an attempt is made to switch from a fast interrupt or IPI. This is 373 * necessary to properly take fatal kernel traps on SMP machines if 374 * get_mplock() has to block. 375 */ 376 377 void 378 user_trap(struct trapframe *frame) 379 { 380 struct globaldata *gd = mycpu; 381 struct thread *td = gd->gd_curthread; 382 struct lwp *lp = td->td_lwp; 383 struct proc *p; 384 int sticks = 0; 385 int i = 0, ucode = 0, type, code; 386 #ifdef SMP 387 int have_mplock = 0; 388 #endif 389 #ifdef INVARIANTS 390 int crit_count = td->td_critcount; 391 lwkt_tokref_t curstop = td->td_toks_stop; 392 #endif 393 vm_offset_t eva; 394 395 p = td->td_proc; 396 397 if (frame->tf_trapno == T_PAGEFLT) 398 eva = frame->tf_addr; 399 else 400 eva = 0; 401 #if 0 402 kprintf("USER_TRAP AT %08lx xflags %ld trapno %ld eva %08lx\n", 403 frame->tf_rip, frame->tf_xflags, frame->tf_trapno, eva); 404 #endif 405 406 /* 407 * Everything coming from user mode runs through user_trap, 408 * including system calls. 409 */ 410 if (frame->tf_trapno == T_FAST_SYSCALL) { 411 syscall2(frame); 412 return; 413 } 414 415 KTR_LOG(kernentry_trap, lp->lwp_proc->p_pid, lp->lwp_tid, 416 frame->tf_trapno, eva); 417 418 #ifdef DDB 419 if (db_active) { 420 eva = (frame->tf_trapno == T_PAGEFLT ? rcr2() : 0); 421 ++gd->gd_trap_nesting_level; 422 MAKEMPSAFE(have_mplock); 423 trap_fatal(frame, TRUE, eva); 424 --gd->gd_trap_nesting_level; 425 goto out2; 426 } 427 #endif 428 429 type = frame->tf_trapno; 430 code = frame->tf_err; 431 432 userenter(td, p); 433 434 sticks = (int)td->td_sticks; 435 lp->lwp_md.md_regs = frame; 436 437 switch (type) { 438 case T_PRIVINFLT: /* privileged instruction fault */ 439 ucode = type; 440 i = SIGILL; 441 break; 442 443 case T_BPTFLT: /* bpt instruction fault */ 444 case T_TRCTRAP: /* trace trap */ 445 frame->tf_rflags &= ~PSL_T; 446 i = SIGTRAP; 447 break; 448 449 case T_ARITHTRAP: /* arithmetic trap */ 450 ucode = code; 451 i = SIGFPE; 452 break; 453 454 case T_ASTFLT: /* Allow process switch */ 455 mycpu->gd_cnt.v_soft++; 456 if (mycpu->gd_reqflags & RQF_AST_OWEUPC) { 457 atomic_clear_int(&mycpu->gd_reqflags, RQF_AST_OWEUPC); 458 addupc_task(p, p->p_prof.pr_addr, p->p_prof.pr_ticks); 459 } 460 goto out; 461 462 /* 463 * The following two traps can happen in 464 * vm86 mode, and, if so, we want to handle 465 * them specially. 466 */ 467 case T_PROTFLT: /* general protection fault */ 468 case T_STKFLT: /* stack fault */ 469 #if 0 470 if (frame->tf_eflags & PSL_VM) { 471 i = vm86_emulate((struct vm86frame *)frame); 472 if (i == 0) 473 goto out; 474 break; 475 } 476 #endif 477 /* FALL THROUGH */ 478 479 case T_SEGNPFLT: /* segment not present fault */ 480 case T_TSSFLT: /* invalid TSS fault */ 481 case T_DOUBLEFLT: /* double fault */ 482 default: 483 ucode = code + BUS_SEGM_FAULT ; 484 i = SIGBUS; 485 break; 486 487 case T_PAGEFLT: /* page fault */ 488 MAKEMPSAFE(have_mplock); 489 i = trap_pfault(frame, TRUE, eva); 490 if (i == -1 || i == 0) 491 goto out; 492 493 ucode = T_PAGEFLT; 494 break; 495 496 case T_DIVIDE: /* integer divide fault */ 497 ucode = FPE_INTDIV; 498 i = SIGFPE; 499 break; 500 501 #if NISA > 0 502 case T_NMI: 503 MAKEMPSAFE(have_mplock); 504 /* machine/parity/power fail/"kitchen sink" faults */ 505 if (isa_nmi(code) == 0) { 506 #ifdef DDB 507 /* 508 * NMI can be hooked up to a pushbutton 509 * for debugging. 510 */ 511 if (ddb_on_nmi) { 512 kprintf ("NMI ... going to debugger\n"); 513 kdb_trap (type, 0, frame); 514 } 515 #endif /* DDB */ 516 goto out2; 517 } else if (panic_on_nmi) 518 panic("NMI indicates hardware failure"); 519 break; 520 #endif /* NISA > 0 */ 521 522 case T_OFLOW: /* integer overflow fault */ 523 ucode = FPE_INTOVF; 524 i = SIGFPE; 525 break; 526 527 case T_BOUND: /* bounds check fault */ 528 ucode = FPE_FLTSUB; 529 i = SIGFPE; 530 break; 531 532 case T_DNA: 533 /* 534 * Virtual kernel intercept - pass the DNA exception 535 * to the (emulated) virtual kernel if it asked to handle 536 * it. This occurs when the virtual kernel is holding 537 * onto the FP context for a different emulated 538 * process then the one currently running. 539 * 540 * We must still call npxdna() since we may have 541 * saved FP state that the (emulated) virtual kernel 542 * needs to hand over to a different emulated process. 543 */ 544 if (lp->lwp_vkernel && lp->lwp_vkernel->ve && 545 (td->td_pcb->pcb_flags & FP_VIRTFP) 546 ) { 547 npxdna(frame); 548 break; 549 } 550 /* 551 * The kernel may have switched out the FP unit's 552 * state, causing the user process to take a fault 553 * when it tries to use the FP unit. Restore the 554 * state here 555 */ 556 if (npxdna(frame)) 557 goto out; 558 if (!pmath_emulate) { 559 i = SIGFPE; 560 ucode = FPE_FPU_NP_TRAP; 561 break; 562 } 563 i = (*pmath_emulate)(frame); 564 if (i == 0) { 565 if (!(frame->tf_rflags & PSL_T)) 566 goto out2; 567 frame->tf_rflags &= ~PSL_T; 568 i = SIGTRAP; 569 } 570 /* else ucode = emulator_only_knows() XXX */ 571 break; 572 573 case T_FPOPFLT: /* FPU operand fetch fault */ 574 ucode = T_FPOPFLT; 575 i = SIGILL; 576 break; 577 578 case T_XMMFLT: /* SIMD floating-point exception */ 579 ucode = 0; /* XXX */ 580 i = SIGFPE; 581 break; 582 } 583 584 /* 585 * Virtual kernel intercept - if the fault is directly related to a 586 * VM context managed by a virtual kernel then let the virtual kernel 587 * handle it. 588 */ 589 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) { 590 vkernel_trap(lp, frame); 591 goto out; 592 } 593 594 /* 595 * Translate fault for emulators (e.g. Linux) 596 */ 597 if (*p->p_sysent->sv_transtrap) 598 i = (*p->p_sysent->sv_transtrap)(i, type); 599 600 MAKEMPSAFE(have_mplock); 601 trapsignal(lp, i, ucode); 602 603 #ifdef DEBUG 604 if (type <= MAX_TRAP_MSG) { 605 uprintf("fatal process exception: %s", 606 trap_msg[type]); 607 if ((type == T_PAGEFLT) || (type == T_PROTFLT)) 608 uprintf(", fault VA = 0x%lx", (u_long)eva); 609 uprintf("\n"); 610 } 611 #endif 612 613 out: 614 userret(lp, frame, sticks); 615 userexit(lp); 616 out2: ; 617 #ifdef SMP 618 if (have_mplock) 619 rel_mplock(); 620 #endif 621 KTR_LOG(kernentry_trap_ret, lp->lwp_proc->p_pid, lp->lwp_tid); 622 #ifdef INVARIANTS 623 KASSERT(crit_count == td->td_critcount, 624 ("trap: critical section count mismatch! %d/%d", 625 crit_count, td->td_pri)); 626 KASSERT(curstop == td->td_toks_stop, 627 ("trap: extra tokens held after trap! %ld/%ld", 628 curstop - &td->td_toks_base, 629 td->td_toks_stop - &td->td_toks_base)); 630 #endif 631 } 632 633 void 634 kern_trap(struct trapframe *frame) 635 { 636 struct globaldata *gd = mycpu; 637 struct thread *td = gd->gd_curthread; 638 struct lwp *lp; 639 struct proc *p; 640 int i = 0, ucode = 0, type, code; 641 #ifdef SMP 642 int have_mplock = 0; 643 #endif 644 #ifdef INVARIANTS 645 int crit_count = td->td_critcount; 646 lwkt_tokref_t curstop = td->td_toks_stop; 647 #endif 648 vm_offset_t eva; 649 650 lp = td->td_lwp; 651 p = td->td_proc; 652 653 if (frame->tf_trapno == T_PAGEFLT) 654 eva = frame->tf_addr; 655 else 656 eva = 0; 657 658 #ifdef DDB 659 if (db_active) { 660 ++gd->gd_trap_nesting_level; 661 MAKEMPSAFE(have_mplock); 662 trap_fatal(frame, FALSE, eva); 663 --gd->gd_trap_nesting_level; 664 goto out2; 665 } 666 #endif 667 668 type = frame->tf_trapno; 669 code = frame->tf_err; 670 671 #if 0 672 kernel_trap: 673 #endif 674 /* kernel trap */ 675 676 switch (type) { 677 case T_PAGEFLT: /* page fault */ 678 MAKEMPSAFE(have_mplock); 679 trap_pfault(frame, FALSE, eva); 680 goto out2; 681 682 case T_DNA: 683 /* 684 * The kernel may be using npx for copying or other 685 * purposes. 686 */ 687 panic("kernel NPX should not happen"); 688 if (npxdna(frame)) 689 goto out2; 690 break; 691 692 case T_PROTFLT: /* general protection fault */ 693 case T_SEGNPFLT: /* segment not present fault */ 694 /* 695 * Invalid segment selectors and out of bounds 696 * %eip's and %esp's can be set up in user mode. 697 * This causes a fault in kernel mode when the 698 * kernel tries to return to user mode. We want 699 * to get this fault so that we can fix the 700 * problem here and not have to check all the 701 * selectors and pointers when the user changes 702 * them. 703 */ 704 if (mycpu->gd_intr_nesting_level == 0) { 705 if (td->td_pcb->pcb_onfault) { 706 frame->tf_rip = 707 (register_t)td->td_pcb->pcb_onfault; 708 goto out2; 709 } 710 } 711 break; 712 713 case T_TSSFLT: 714 /* 715 * PSL_NT can be set in user mode and isn't cleared 716 * automatically when the kernel is entered. This 717 * causes a TSS fault when the kernel attempts to 718 * `iret' because the TSS link is uninitialized. We 719 * want to get this fault so that we can fix the 720 * problem here and not every time the kernel is 721 * entered. 722 */ 723 if (frame->tf_rflags & PSL_NT) { 724 frame->tf_rflags &= ~PSL_NT; 725 goto out2; 726 } 727 break; 728 729 case T_TRCTRAP: /* trace trap */ 730 #if 0 731 if (frame->tf_eip == (int)IDTVEC(syscall)) { 732 /* 733 * We've just entered system mode via the 734 * syscall lcall. Continue single stepping 735 * silently until the syscall handler has 736 * saved the flags. 737 */ 738 goto out2; 739 } 740 if (frame->tf_eip == (int)IDTVEC(syscall) + 1) { 741 /* 742 * The syscall handler has now saved the 743 * flags. Stop single stepping it. 744 */ 745 frame->tf_eflags &= ~PSL_T; 746 goto out2; 747 } 748 #endif 749 #if 0 750 /* 751 * Ignore debug register trace traps due to 752 * accesses in the user's address space, which 753 * can happen under several conditions such as 754 * if a user sets a watchpoint on a buffer and 755 * then passes that buffer to a system call. 756 * We still want to get TRCTRAPS for addresses 757 * in kernel space because that is useful when 758 * debugging the kernel. 759 */ 760 if (user_dbreg_trap()) { 761 /* 762 * Reset breakpoint bits because the 763 * processor doesn't 764 */ 765 load_dr6(rdr6() & 0xfffffff0); 766 goto out2; 767 } 768 #endif 769 /* 770 * Fall through (TRCTRAP kernel mode, kernel address) 771 */ 772 case T_BPTFLT: 773 /* 774 * If DDB is enabled, let it handle the debugger trap. 775 * Otherwise, debugger traps "can't happen". 776 */ 777 #ifdef DDB 778 MAKEMPSAFE(have_mplock); 779 if (kdb_trap (type, 0, frame)) 780 goto out2; 781 #endif 782 break; 783 case T_DIVIDE: 784 MAKEMPSAFE(have_mplock); 785 trap_fatal(frame, FALSE, eva); 786 goto out2; 787 case T_NMI: 788 MAKEMPSAFE(have_mplock); 789 trap_fatal(frame, FALSE, eva); 790 goto out2; 791 case T_SYSCALL80: 792 case T_FAST_SYSCALL: 793 /* 794 * Ignore this trap generated from a spurious SIGTRAP. 795 * 796 * single stepping in / syscalls leads to spurious / SIGTRAP 797 * so ignore 798 * 799 * Haiku (c) 2007 Simon 'corecode' Schubert 800 */ 801 goto out2; 802 } 803 804 /* 805 * Translate fault for emulators (e.g. Linux) 806 */ 807 if (*p->p_sysent->sv_transtrap) 808 i = (*p->p_sysent->sv_transtrap)(i, type); 809 810 MAKEMPSAFE(have_mplock); 811 trapsignal(lp, i, ucode); 812 813 #ifdef DEBUG 814 if (type <= MAX_TRAP_MSG) { 815 uprintf("fatal process exception: %s", 816 trap_msg[type]); 817 if ((type == T_PAGEFLT) || (type == T_PROTFLT)) 818 uprintf(", fault VA = 0x%lx", (u_long)eva); 819 uprintf("\n"); 820 } 821 #endif 822 823 out2: 824 ; 825 #ifdef SMP 826 if (have_mplock) 827 rel_mplock(); 828 #endif 829 #ifdef INVARIANTS 830 KASSERT(crit_count == td->td_critcount, 831 ("trap: critical section count mismatch! %d/%d", 832 crit_count, td->td_pri)); 833 KASSERT(curstop == td->td_toks_stop, 834 ("trap: extra tokens held after trap! %ld/%ld", 835 curstop - &td->td_toks_base, 836 td->td_toks_stop - &td->td_toks_base)); 837 #endif 838 } 839 840 int 841 trap_pfault(struct trapframe *frame, int usermode, vm_offset_t eva) 842 { 843 vm_offset_t va; 844 struct vmspace *vm = NULL; 845 vm_map_t map = 0; 846 int rv = 0; 847 vm_prot_t ftype; 848 thread_t td = curthread; 849 struct lwp *lp = td->td_lwp; 850 int fault_flags; 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_flags = 0; 901 if (usermode) 902 fault_flags |= VM_FAULT_BURST; 903 if (ftype & VM_PROT_WRITE) 904 fault_flags |= VM_FAULT_DIRTY; 905 else 906 fault_flags |= VM_FAULT_NORMAL; 907 908 rv = vm_fault(map, va, ftype, fault_flags); 909 PRELE(lp->lwp_proc); 910 } else { 911 /* 912 * Don't have to worry about process locking or stacks in the kernel. 913 */ 914 rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL); 915 } 916 917 if (rv == KERN_SUCCESS) 918 return (0); 919 nogo: 920 if (!usermode) { 921 if (td->td_gd->gd_intr_nesting_level == 0 && 922 td->td_pcb->pcb_onfault) { 923 frame->tf_rip = (register_t)td->td_pcb->pcb_onfault; 924 return (0); 925 } 926 trap_fatal(frame, usermode, eva); 927 return (-1); 928 } 929 930 /* 931 * NOTE: on x86_64 we have a tf_addr field in the trapframe, no 932 * kludge is needed to pass the fault address to signal handlers. 933 */ 934 struct proc *p = td->td_proc; 935 kprintf("seg-fault accessing address %p rip=%p pid=%d p_comm=%s\n", 936 (void *)va, (void *)frame->tf_rip, p->p_pid, p->p_comm); 937 /* Debugger("seg-fault"); */ 938 939 return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV); 940 } 941 942 static void 943 trap_fatal(struct trapframe *frame, int usermode, vm_offset_t eva) 944 { 945 int code, type, ss; 946 long rsp; 947 948 code = frame->tf_xflags; 949 type = frame->tf_trapno; 950 951 if (type <= MAX_TRAP_MSG) { 952 kprintf("\n\nFatal trap %d: %s while in %s mode\n", 953 type, trap_msg[type], 954 (usermode ? "user" : "kernel")); 955 } 956 #ifdef SMP 957 /* two separate prints in case of a trap on an unmapped page */ 958 kprintf("cpuid = %d\n", mycpu->gd_cpuid); 959 #endif 960 if (type == T_PAGEFLT) { 961 kprintf("fault virtual address = %p\n", (void *)eva); 962 kprintf("fault code = %s %s, %s\n", 963 usermode ? "user" : "supervisor", 964 code & PGEX_W ? "write" : "read", 965 code & PGEX_P ? "protection violation" : "page not present"); 966 } 967 kprintf("instruction pointer = 0x%lx:0x%lx\n", 968 frame->tf_cs & 0xffff, frame->tf_rip); 969 if (usermode) { 970 ss = frame->tf_ss & 0xffff; 971 rsp = frame->tf_rsp; 972 } else { 973 ss = GSEL(GDATA_SEL, SEL_KPL); 974 rsp = (long)&frame->tf_rsp; 975 } 976 kprintf("stack pointer = 0x%x:0x%lx\n", ss, rsp); 977 kprintf("frame pointer = 0x%x:0x%lx\n", ss, frame->tf_rbp); 978 kprintf("processor eflags = "); 979 if (frame->tf_rflags & PSL_T) 980 kprintf("trace trap, "); 981 if (frame->tf_rflags & PSL_I) 982 kprintf("interrupt enabled, "); 983 if (frame->tf_rflags & PSL_NT) 984 kprintf("nested task, "); 985 if (frame->tf_rflags & PSL_RF) 986 kprintf("resume, "); 987 #if 0 988 if (frame->tf_eflags & PSL_VM) 989 kprintf("vm86, "); 990 #endif 991 kprintf("IOPL = %jd\n", (intmax_t)((frame->tf_rflags & PSL_IOPL) >> 12)); 992 kprintf("current process = "); 993 if (curproc) { 994 kprintf("%lu (%s)\n", 995 (u_long)curproc->p_pid, curproc->p_comm ? 996 curproc->p_comm : ""); 997 } else { 998 kprintf("Idle\n"); 999 } 1000 kprintf("current thread = pri %d ", curthread->td_pri); 1001 if (curthread->td_critcount) 1002 kprintf("(CRIT)"); 1003 kprintf("\n"); 1004 #ifdef SMP 1005 /** 1006 * XXX FIXME: 1007 * we probably SHOULD have stopped the other CPUs before now! 1008 * another CPU COULD have been touching cpl at this moment... 1009 */ 1010 kprintf(" <- SMP: XXX"); 1011 #endif 1012 kprintf("\n"); 1013 1014 #ifdef KDB 1015 if (kdb_trap(&psl)) 1016 return; 1017 #endif 1018 #ifdef DDB 1019 if ((debugger_on_panic || db_active) && kdb_trap(type, code, frame)) 1020 return; 1021 #endif 1022 kprintf("trap number = %d\n", type); 1023 if (type <= MAX_TRAP_MSG) 1024 panic("%s", trap_msg[type]); 1025 else 1026 panic("unknown/reserved trap"); 1027 } 1028 1029 /* 1030 * Double fault handler. Called when a fault occurs while writing 1031 * a frame for a trap/exception onto the stack. This usually occurs 1032 * when the stack overflows (such is the case with infinite recursion, 1033 * for example). 1034 * 1035 * XXX Note that the current PTD gets replaced by IdlePTD when the 1036 * task switch occurs. This means that the stack that was active at 1037 * the time of the double fault is not available at <kstack> unless 1038 * the machine was idle when the double fault occurred. The downside 1039 * of this is that "trace <ebp>" in ddb won't work. 1040 */ 1041 void 1042 dblfault_handler(void) 1043 { 1044 #if JG 1045 struct mdglobaldata *gd = mdcpu; 1046 #endif 1047 1048 kprintf("\nFatal double fault:\n"); 1049 #if JG 1050 kprintf("rip = 0x%lx\n", gd->gd_common_tss.tss_rip); 1051 kprintf("rsp = 0x%lx\n", gd->gd_common_tss.tss_rsp); 1052 kprintf("rbp = 0x%lx\n", gd->gd_common_tss.tss_rbp); 1053 #endif 1054 #ifdef SMP 1055 /* two separate prints in case of a trap on an unmapped page */ 1056 kprintf("cpuid = %d\n", mycpu->gd_cpuid); 1057 #endif 1058 panic("double fault"); 1059 } 1060 1061 /* 1062 * Compensate for 386 brain damage (missing URKR). 1063 * This is a little simpler than the pagefault handler in trap() because 1064 * it the page tables have already been faulted in and high addresses 1065 * are thrown out early for other reasons. 1066 */ 1067 int 1068 trapwrite(unsigned addr) 1069 { 1070 struct lwp *lp; 1071 vm_offset_t va; 1072 struct vmspace *vm; 1073 int rv; 1074 1075 va = trunc_page((vm_offset_t)addr); 1076 /* 1077 * XXX - MAX is END. Changed > to >= for temp. fix. 1078 */ 1079 if (va >= VM_MAX_USER_ADDRESS) 1080 return (1); 1081 1082 lp = curthread->td_lwp; 1083 vm = lp->lwp_vmspace; 1084 1085 PHOLD(lp->lwp_proc); 1086 1087 if (!grow_stack (lp->lwp_proc, va)) { 1088 PRELE(lp->lwp_proc); 1089 return (1); 1090 } 1091 1092 /* 1093 * fault the data page 1094 */ 1095 rv = vm_fault(&vm->vm_map, va, VM_PROT_WRITE, VM_FAULT_DIRTY); 1096 1097 PRELE(lp->lwp_proc); 1098 1099 if (rv != KERN_SUCCESS) 1100 return 1; 1101 1102 return (0); 1103 } 1104 1105 /* 1106 * syscall2 - MP aware system call request C handler 1107 * 1108 * A system call is essentially treated as a trap except that the 1109 * MP lock is not held on entry or return. We are responsible for 1110 * obtaining the MP lock if necessary and for handling ASTs 1111 * (e.g. a task switch) prior to return. 1112 * 1113 * In general, only simple access and manipulation of curproc and 1114 * the current stack is allowed without having to hold MP lock. 1115 * 1116 * MPSAFE - note that large sections of this routine are run without 1117 * the MP lock. 1118 */ 1119 void 1120 syscall2(struct trapframe *frame) 1121 { 1122 struct thread *td = curthread; 1123 struct proc *p = td->td_proc; 1124 struct lwp *lp = td->td_lwp; 1125 caddr_t params; 1126 struct sysent *callp; 1127 register_t orig_tf_rflags; 1128 int sticks; 1129 int error; 1130 int narg; 1131 #ifdef INVARIANTS 1132 int crit_count = td->td_critcount; 1133 lwkt_tokref_t curstop = td->td_toks_stop; 1134 #endif 1135 #ifdef SMP 1136 int have_mplock = 0; 1137 #endif 1138 register_t *argp; 1139 u_int code; 1140 int reg, regcnt; 1141 union sysunion args; 1142 register_t *argsdst; 1143 1144 mycpu->gd_cnt.v_syscall++; 1145 1146 KTR_LOG(kernentry_syscall, lp->lwp_proc->p_pid, lp->lwp_tid, 1147 frame->tf_rax); 1148 1149 userenter(td, p); /* lazy raise our priority */ 1150 1151 reg = 0; 1152 regcnt = 6; 1153 /* 1154 * Misc 1155 */ 1156 sticks = (int)td->td_sticks; 1157 orig_tf_rflags = frame->tf_rflags; 1158 1159 /* 1160 * Virtual kernel intercept - if a VM context managed by a virtual 1161 * kernel issues a system call the virtual kernel handles it, not us. 1162 * Restore the virtual kernel context and return from its system 1163 * call. The current frame is copied out to the virtual kernel. 1164 */ 1165 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) { 1166 vkernel_trap(lp, frame); 1167 error = EJUSTRETURN; 1168 goto out; 1169 } 1170 1171 /* 1172 * Get the system call parameters and account for time 1173 */ 1174 lp->lwp_md.md_regs = frame; 1175 params = (caddr_t)frame->tf_rsp + sizeof(register_t); 1176 code = frame->tf_rax; 1177 1178 if (p->p_sysent->sv_prepsyscall) { 1179 (*p->p_sysent->sv_prepsyscall)( 1180 frame, (int *)(&args.nosys.sysmsg + 1), 1181 &code, ¶ms); 1182 } else { 1183 if (code == SYS_syscall || code == SYS___syscall) { 1184 code = frame->tf_rdi; 1185 reg++; 1186 regcnt--; 1187 } 1188 } 1189 1190 if (p->p_sysent->sv_mask) 1191 code &= p->p_sysent->sv_mask; 1192 1193 if (code >= p->p_sysent->sv_size) 1194 callp = &p->p_sysent->sv_table[0]; 1195 else 1196 callp = &p->p_sysent->sv_table[code]; 1197 1198 narg = callp->sy_narg & SYF_ARGMASK; 1199 1200 /* 1201 * On x86_64 we get up to six arguments in registers. The rest are 1202 * on the stack. The first six members of 'struct trapframe' happen 1203 * to be the registers used to pass arguments, in exactly the right 1204 * order. 1205 */ 1206 argp = &frame->tf_rdi; 1207 argp += reg; 1208 argsdst = (register_t *)(&args.nosys.sysmsg + 1); 1209 /* 1210 * JG can we overflow the space pointed to by 'argsdst' 1211 * either with 'bcopy' or with 'copyin'? 1212 */ 1213 bcopy(argp, argsdst, sizeof(register_t) * regcnt); 1214 /* 1215 * copyin is MP aware, but the tracing code is not 1216 */ 1217 if (narg > regcnt) { 1218 KASSERT(params != NULL, ("copyin args with no params!")); 1219 error = copyin(params, &argsdst[regcnt], 1220 (narg - regcnt) * sizeof(register_t)); 1221 if (error) { 1222 #ifdef KTRACE 1223 if (KTRPOINT(td, KTR_SYSCALL)) { 1224 MAKEMPSAFE(have_mplock); 1225 1226 ktrsyscall(lp, code, narg, 1227 (void *)(&args.nosys.sysmsg + 1)); 1228 } 1229 #endif 1230 goto bad; 1231 } 1232 } 1233 1234 #ifdef KTRACE 1235 if (KTRPOINT(td, KTR_SYSCALL)) { 1236 MAKEMPSAFE(have_mplock); 1237 ktrsyscall(lp, code, narg, (void *)(&args.nosys.sysmsg + 1)); 1238 } 1239 #endif 1240 1241 /* 1242 * Default return value is 0 (will be copied to %rax). Double-value 1243 * returns use %rax and %rdx. %rdx is left unchanged for system 1244 * calls which return only one result. 1245 */ 1246 args.sysmsg_fds[0] = 0; 1247 args.sysmsg_fds[1] = frame->tf_rdx; 1248 1249 /* 1250 * The syscall might manipulate the trap frame. If it does it 1251 * will probably return EJUSTRETURN. 1252 */ 1253 args.sysmsg_frame = frame; 1254 1255 STOPEVENT(p, S_SCE, narg); /* MP aware */ 1256 1257 /* 1258 * NOTE: All system calls run MPSAFE now. The system call itself 1259 * is responsible for getting the MP lock. 1260 */ 1261 error = (*callp->sy_call)(&args); 1262 1263 #if 0 1264 kprintf("system call %d returned %d\n", code, error); 1265 #endif 1266 1267 out: 1268 /* 1269 * MP SAFE (we may or may not have the MP lock at this point) 1270 */ 1271 switch (error) { 1272 case 0: 1273 /* 1274 * Reinitialize proc pointer `p' as it may be different 1275 * if this is a child returning from fork syscall. 1276 */ 1277 p = curproc; 1278 lp = curthread->td_lwp; 1279 frame->tf_rax = args.sysmsg_fds[0]; 1280 frame->tf_rdx = args.sysmsg_fds[1]; 1281 frame->tf_rflags &= ~PSL_C; 1282 break; 1283 case ERESTART: 1284 /* 1285 * Reconstruct pc, we know that 'syscall' is 2 bytes. 1286 * We have to do a full context restore so that %r10 1287 * (which was holding the value of %rcx) is restored for 1288 * the next iteration. 1289 */ 1290 frame->tf_rip -= frame->tf_err; 1291 frame->tf_r10 = frame->tf_rcx; 1292 break; 1293 case EJUSTRETURN: 1294 break; 1295 case EASYNC: 1296 panic("Unexpected EASYNC return value (for now)"); 1297 default: 1298 bad: 1299 if (p->p_sysent->sv_errsize) { 1300 if (error >= p->p_sysent->sv_errsize) 1301 error = -1; /* XXX */ 1302 else 1303 error = p->p_sysent->sv_errtbl[error]; 1304 } 1305 frame->tf_rax = error; 1306 frame->tf_rflags |= PSL_C; 1307 break; 1308 } 1309 1310 /* 1311 * Traced syscall. trapsignal() is not MP aware. 1312 */ 1313 if (orig_tf_rflags & PSL_T) { 1314 MAKEMPSAFE(have_mplock); 1315 frame->tf_rflags &= ~PSL_T; 1316 trapsignal(lp, SIGTRAP, 0); 1317 } 1318 1319 /* 1320 * Handle reschedule and other end-of-syscall issues 1321 */ 1322 userret(lp, frame, sticks); 1323 1324 #ifdef KTRACE 1325 if (KTRPOINT(td, KTR_SYSRET)) { 1326 MAKEMPSAFE(have_mplock); 1327 ktrsysret(lp, code, error, args.sysmsg_result); 1328 } 1329 #endif 1330 1331 /* 1332 * This works because errno is findable through the 1333 * register set. If we ever support an emulation where this 1334 * is not the case, this code will need to be revisited. 1335 */ 1336 STOPEVENT(p, S_SCX, code); 1337 1338 userexit(lp); 1339 #ifdef SMP 1340 /* 1341 * Release the MP lock if we had to get it 1342 */ 1343 if (have_mplock) 1344 rel_mplock(); 1345 #endif 1346 KTR_LOG(kernentry_syscall_ret, lp->lwp_proc->p_pid, lp->lwp_tid, error); 1347 #ifdef INVARIANTS 1348 KASSERT(&td->td_toks_base == td->td_toks_stop, 1349 ("syscall: critical section count mismatch! %d/%d", 1350 crit_count, td->td_pri)); 1351 KASSERT(curstop == td->td_toks_stop, 1352 ("syscall: extra tokens held after trap! %ld", 1353 td->td_toks_stop - &td->td_toks_base)); 1354 #endif 1355 } 1356 1357 /* 1358 * NOTE: mplock not held at any point 1359 */ 1360 void 1361 fork_return(struct lwp *lp, struct trapframe *frame) 1362 { 1363 frame->tf_rax = 0; /* Child returns zero */ 1364 frame->tf_rflags &= ~PSL_C; /* success */ 1365 frame->tf_rdx = 1; 1366 1367 generic_lwp_return(lp, frame); 1368 KTR_LOG(kernentry_fork_ret, lp->lwp_proc->p_pid, lp->lwp_tid); 1369 } 1370 1371 /* 1372 * Simplified back end of syscall(), used when returning from fork() 1373 * directly into user mode. 1374 * 1375 * This code will return back into the fork trampoline code which then 1376 * runs doreti. 1377 * 1378 * NOTE: The mplock is not held at any point. 1379 */ 1380 void 1381 generic_lwp_return(struct lwp *lp, struct trapframe *frame) 1382 { 1383 struct proc *p = lp->lwp_proc; 1384 1385 /* 1386 * Newly forked processes are given a kernel priority. We have to 1387 * adjust the priority to a normal user priority and fake entry 1388 * into the kernel (call userenter()) to install a passive release 1389 * function just in case userret() decides to stop the process. This 1390 * can occur when ^Z races a fork. If we do not install the passive 1391 * release function the current process designation will not be 1392 * released when the thread goes to sleep. 1393 */ 1394 lwkt_setpri_self(TDPRI_USER_NORM); 1395 userenter(lp->lwp_thread, p); 1396 userret(lp, frame, 0); 1397 #ifdef KTRACE 1398 if (KTRPOINT(lp->lwp_thread, KTR_SYSRET)) 1399 ktrsysret(lp, SYS_fork, 0, 0); 1400 #endif 1401 lp->lwp_flags |= LWP_PASSIVE_ACQ; 1402 userexit(lp); 1403 lp->lwp_flags &= ~LWP_PASSIVE_ACQ; 1404 } 1405 1406 /* 1407 * doreti has turned into this. The frame is directly on the stack. We 1408 * pull everything else we need (fpu and tls context) from the current 1409 * thread. 1410 * 1411 * Note on fpu interactions: In a virtual kernel, the fpu context for 1412 * an emulated user mode process is not shared with the virtual kernel's 1413 * fpu context, so we only have to 'stack' fpu contexts within the virtual 1414 * kernel itself, and not even then since the signal() contexts that we care 1415 * about save and restore the FPU state (I think anyhow). 1416 * 1417 * vmspace_ctl() returns an error only if it had problems instaling the 1418 * context we supplied or problems copying data to/from our VM space. 1419 */ 1420 void 1421 go_user(struct intrframe *frame) 1422 { 1423 struct trapframe *tf = (void *)&frame->if_rdi; 1424 int r; 1425 1426 /* 1427 * Interrupts may be disabled on entry, make sure all signals 1428 * can be received before beginning our loop. 1429 */ 1430 sigsetmask(0); 1431 1432 /* 1433 * Switch to the current simulated user process, then call 1434 * user_trap() when we break out of it (usually due to a signal). 1435 */ 1436 for (;;) { 1437 /* 1438 * Tell the real kernel whether it is ok to use the FP 1439 * unit or not. 1440 */ 1441 if (mdcpu->gd_npxthread == curthread) { 1442 tf->tf_xflags &= ~PGEX_FPFAULT; 1443 } else { 1444 tf->tf_xflags |= PGEX_FPFAULT; 1445 } 1446 1447 /* 1448 * Run emulated user process context. This call interlocks 1449 * with new mailbox signals. 1450 * 1451 * Set PGEX_U unconditionally, indicating a user frame (the 1452 * bit is normally set only by T_PAGEFLT). 1453 */ 1454 r = vmspace_ctl(&curproc->p_vmspace->vm_pmap, VMSPACE_CTL_RUN, 1455 tf, &curthread->td_savevext); 1456 frame->if_xflags |= PGEX_U; 1457 #if 0 1458 kprintf("GO USER %d trap %ld EVA %08lx RIP %08lx RSP %08lx XFLAGS %02lx/%02lx\n", 1459 r, tf->tf_trapno, tf->tf_addr, tf->tf_rip, tf->tf_rsp, 1460 tf->tf_xflags, frame->if_xflags); 1461 #endif 1462 if (r < 0) { 1463 if (errno != EINTR) 1464 panic("vmspace_ctl failed error %d", errno); 1465 } else { 1466 if (tf->tf_trapno) { 1467 user_trap(tf); 1468 } 1469 } 1470 if (mycpu->gd_reqflags & RQF_AST_MASK) { 1471 tf->tf_trapno = T_ASTFLT; 1472 user_trap(tf); 1473 } 1474 tf->tf_trapno = 0; 1475 } 1476 } 1477 1478 /* 1479 * If PGEX_FPFAULT is set then set FP_VIRTFP in the PCB to force a T_DNA 1480 * fault (which is then passed back to the virtual kernel) if an attempt is 1481 * made to use the FP unit. 1482 * 1483 * XXX this is a fairly big hack. 1484 */ 1485 void 1486 set_vkernel_fp(struct trapframe *frame) 1487 { 1488 struct thread *td = curthread; 1489 1490 if (frame->tf_xflags & PGEX_FPFAULT) { 1491 td->td_pcb->pcb_flags |= FP_VIRTFP; 1492 if (mdcpu->gd_npxthread == td) 1493 npxexit(); 1494 } else { 1495 td->td_pcb->pcb_flags &= ~FP_VIRTFP; 1496 } 1497 } 1498 1499 /* 1500 * Called from vkernel_trap() to fixup the vkernel's syscall 1501 * frame for vmspace_ctl() return. 1502 */ 1503 void 1504 cpu_vkernel_trap(struct trapframe *frame, int error) 1505 { 1506 frame->tf_rax = error; 1507 if (error) 1508 frame->tf_rflags |= PSL_C; 1509 else 1510 frame->tf_rflags &= ~PSL_C; 1511 } 1512