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 #define MAKEMPSAFE(have_mplock) \ 97 if (have_mplock == 0) { \ 98 get_mplock(); \ 99 have_mplock = 1; \ 100 } 101 102 int (*pmath_emulate) (struct trapframe *); 103 104 extern int trapwrite (unsigned addr); 105 106 static int trap_pfault (struct trapframe *, int, vm_offset_t); 107 static void trap_fatal (struct trapframe *, int, vm_offset_t); 108 void dblfault_handler (void); 109 110 #if 0 111 extern inthand_t IDTVEC(syscall); 112 #endif 113 114 #define MAX_TRAP_MSG 30 115 static char *trap_msg[] = { 116 "", /* 0 unused */ 117 "privileged instruction fault", /* 1 T_PRIVINFLT */ 118 "", /* 2 unused */ 119 "breakpoint instruction fault", /* 3 T_BPTFLT */ 120 "", /* 4 unused */ 121 "", /* 5 unused */ 122 "arithmetic trap", /* 6 T_ARITHTRAP */ 123 "system forced exception", /* 7 T_ASTFLT */ 124 "", /* 8 unused */ 125 "general protection fault", /* 9 T_PROTFLT */ 126 "trace trap", /* 10 T_TRCTRAP */ 127 "", /* 11 unused */ 128 "page fault", /* 12 T_PAGEFLT */ 129 "", /* 13 unused */ 130 "alignment fault", /* 14 T_ALIGNFLT */ 131 "", /* 15 unused */ 132 "", /* 16 unused */ 133 "", /* 17 unused */ 134 "integer divide fault", /* 18 T_DIVIDE */ 135 "non-maskable interrupt trap", /* 19 T_NMI */ 136 "overflow trap", /* 20 T_OFLOW */ 137 "FPU bounds check fault", /* 21 T_BOUND */ 138 "FPU device not available", /* 22 T_DNA */ 139 "double fault", /* 23 T_DOUBLEFLT */ 140 "FPU operand fetch fault", /* 24 T_FPOPFLT */ 141 "invalid TSS fault", /* 25 T_TSSFLT */ 142 "segment not present fault", /* 26 T_SEGNPFLT */ 143 "stack fault", /* 27 T_STKFLT */ 144 "machine check trap", /* 28 T_MCHK */ 145 "SIMD floating-point exception", /* 29 T_XMMFLT */ 146 "reserved (unknown) fault", /* 30 T_RESERVED */ 147 }; 148 149 #ifdef DDB 150 static int ddb_on_nmi = 1; 151 SYSCTL_INT(_machdep, OID_AUTO, ddb_on_nmi, CTLFLAG_RW, 152 &ddb_on_nmi, 0, "Go to DDB on NMI"); 153 #endif 154 static int panic_on_nmi = 1; 155 SYSCTL_INT(_machdep, OID_AUTO, panic_on_nmi, CTLFLAG_RW, 156 &panic_on_nmi, 0, "Panic on NMI"); 157 static int fast_release; 158 SYSCTL_INT(_machdep, OID_AUTO, fast_release, CTLFLAG_RW, 159 &fast_release, 0, "Passive Release was optimal"); 160 static int slow_release; 161 SYSCTL_INT(_machdep, OID_AUTO, slow_release, CTLFLAG_RW, 162 &slow_release, 0, "Passive Release was nonoptimal"); 163 164 MALLOC_DEFINE(M_SYSMSG, "sysmsg", "sysmsg structure"); 165 extern int max_sysmsg; 166 167 /* 168 * Passively intercepts the thread switch function to increase 169 * the thread priority from a user priority to a kernel priority, reducing 170 * syscall and trap overhead for the case where no switch occurs. 171 * 172 * Synchronizes td_ucred with p_ucred. This is used by system calls, 173 * signal handling, faults, AST traps, and anything else that enters the 174 * kernel from userland and provides the kernel with a stable read-only 175 * copy of the process ucred. 176 */ 177 static __inline void 178 userenter(struct thread *curtd, struct proc *curp) 179 { 180 struct ucred *ocred; 181 struct ucred *ncred; 182 183 curtd->td_release = lwkt_passive_release; 184 185 if (curtd->td_ucred != curp->p_ucred) { 186 ncred = crhold(curp->p_ucred); 187 ocred = curtd->td_ucred; 188 curtd->td_ucred = ncred; 189 if (ocred) 190 crfree(ocred); 191 } 192 } 193 194 /* 195 * Handle signals, upcalls, profiling, and other AST's and/or tasks that 196 * must be completed before we can return to or try to return to userland. 197 * 198 * Note that td_sticks is a 64 bit quantity, but there's no point doing 64 199 * arithmatic on the delta calculation so the absolute tick values are 200 * truncated to an integer. 201 */ 202 static void 203 userret(struct lwp *lp, struct trapframe *frame, int sticks) 204 { 205 struct proc *p = lp->lwp_proc; 206 int sig; 207 208 /* 209 * Charge system time if profiling. Note: times are in microseconds. 210 * This may do a copyout and block, so do it first even though it 211 * means some system time will be charged as user time. 212 */ 213 if (p->p_flags & P_PROFIL) { 214 addupc_task(p, frame->tf_rip, 215 (u_int)((int)lp->lwp_thread->td_sticks - sticks)); 216 } 217 218 recheck: 219 /* 220 * If the jungle wants us dead, so be it. 221 */ 222 if (lp->lwp_mpflags & LWP_MP_WEXIT) { 223 lwkt_gettoken(&p->p_token); 224 lwp_exit(0); 225 lwkt_reltoken(&p->p_token); /* NOT REACHED */ 226 } 227 228 /* 229 * Block here if we are in a stopped state. 230 */ 231 if (p->p_stat == SSTOP) { 232 lwkt_gettoken(&p->p_token); 233 tstop(); 234 lwkt_reltoken(&p->p_token); 235 goto recheck; 236 } 237 238 /* 239 * Post any pending upcalls. If running a virtual kernel be sure 240 * to restore the virtual kernel's vmspace before posting the upcall. 241 */ 242 if (p->p_flags & (P_SIGVTALRM | P_SIGPROF | P_UPCALLPEND)) { 243 lwkt_gettoken(&p->p_token); 244 if (p->p_flags & P_SIGVTALRM) { 245 p->p_flags &= ~P_SIGVTALRM; 246 ksignal(p, SIGVTALRM); 247 } 248 if (p->p_flags & P_SIGPROF) { 249 p->p_flags &= ~P_SIGPROF; 250 ksignal(p, SIGPROF); 251 } 252 if (p->p_flags & P_UPCALLPEND) { 253 p->p_flags &= ~P_UPCALLPEND; 254 postupcall(lp); 255 } 256 lwkt_reltoken(&p->p_token); 257 goto recheck; 258 } 259 260 /* 261 * Post any pending signals 262 * 263 * WARNING! postsig() can exit and not return. 264 */ 265 if ((sig = CURSIG_TRACE(lp)) != 0) { 266 lwkt_gettoken(&p->p_token); 267 postsig(sig); 268 lwkt_reltoken(&p->p_token); 269 goto recheck; 270 } 271 272 /* 273 * block here if we are swapped out, but still process signals 274 * (such as SIGKILL). proc0 (the swapin scheduler) is already 275 * aware of our situation, we do not have to wake it up. 276 */ 277 if (p->p_flags & P_SWAPPEDOUT) { 278 lwkt_gettoken(&p->p_token); 279 get_mplock(); 280 p->p_flags |= P_SWAPWAIT; 281 swapin_request(); 282 if (p->p_flags & P_SWAPWAIT) 283 tsleep(p, PCATCH, "SWOUT", 0); 284 p->p_flags &= ~P_SWAPWAIT; 285 rel_mplock(); 286 lwkt_reltoken(&p->p_token); 287 goto recheck; 288 } 289 290 /* 291 * In a multi-threaded program it is possible for a thread to change 292 * signal state during a system call which temporarily changes the 293 * signal mask. In this case postsig() might not be run and we 294 * have to restore the mask ourselves. 295 */ 296 if (lp->lwp_flags & LWP_OLDMASK) { 297 lp->lwp_flags &= ~LWP_OLDMASK; 298 lp->lwp_sigmask = lp->lwp_oldsigmask; 299 goto recheck; 300 } 301 } 302 303 /* 304 * Cleanup from userenter and any passive release that might have occured. 305 * We must reclaim the current-process designation before we can return 306 * to usermode. We also handle both LWKT and USER reschedule requests. 307 */ 308 static __inline void 309 userexit(struct lwp *lp) 310 { 311 struct thread *td = lp->lwp_thread; 312 /* globaldata_t gd = td->td_gd; */ 313 314 /* 315 * Handle stop requests at kernel priority. Any requests queued 316 * after this loop will generate another AST. 317 */ 318 while (lp->lwp_proc->p_stat == SSTOP) { 319 lwkt_gettoken(&lp->lwp_proc->p_token); 320 tstop(); 321 lwkt_reltoken(&lp->lwp_proc->p_token); 322 } 323 324 /* 325 * Reduce our priority in preparation for a return to userland. If 326 * our passive release function was still in place, our priority was 327 * never raised and does not need to be reduced. 328 */ 329 lwkt_passive_recover(td); 330 331 /* 332 * Become the current user scheduled process if we aren't already, 333 * and deal with reschedule requests and other factors. 334 */ 335 lp->lwp_proc->p_usched->acquire_curproc(lp); 336 /* WARNING: we may have migrated cpu's */ 337 /* gd = td->td_gd; */ 338 } 339 340 #if !defined(KTR_KERNENTRY) 341 #define KTR_KERNENTRY KTR_ALL 342 #endif 343 KTR_INFO_MASTER(kernentry); 344 KTR_INFO(KTR_KERNENTRY, kernentry, trap, 0, 345 "TRAP(pid %hd, tid %hd, trapno %ld, eva %lu)", 346 pid_t pid, lwpid_t tid, register_t trapno, vm_offset_t eva); 347 KTR_INFO(KTR_KERNENTRY, kernentry, trap_ret, 0, "TRAP_RET(pid %hd, tid %hd)", 348 pid_t pid, lwpid_t tid); 349 KTR_INFO(KTR_KERNENTRY, kernentry, syscall, 0, "SYSC(pid %hd, tid %hd, nr %ld)", 350 pid_t pid, lwpid_t tid, register_t trapno); 351 KTR_INFO(KTR_KERNENTRY, kernentry, syscall_ret, 0, "SYSRET(pid %hd, tid %hd, err %d)", 352 pid_t pid, lwpid_t tid, int err); 353 KTR_INFO(KTR_KERNENTRY, kernentry, fork_ret, 0, "FORKRET(pid %hd, tid %hd)", 354 pid_t pid, lwpid_t tid); 355 356 /* 357 * Exception, fault, and trap interface to the kernel. 358 * This common code is called from assembly language IDT gate entry 359 * routines that prepare a suitable stack frame, and restore this 360 * frame after the exception has been processed. 361 * 362 * This function is also called from doreti in an interlock to handle ASTs. 363 * For example: hardwareint->INTROUTINE->(set ast)->doreti->trap 364 * 365 * NOTE! We have to retrieve the fault address prior to obtaining the 366 * MP lock because get_mplock() may switch out. YYY cr2 really ought 367 * to be retrieved by the assembly code, not here. 368 * 369 * XXX gd_trap_nesting_level currently prevents lwkt_switch() from panicing 370 * if an attempt is made to switch from a fast interrupt or IPI. This is 371 * necessary to properly take fatal kernel traps on SMP machines if 372 * get_mplock() has to block. 373 */ 374 375 void 376 user_trap(struct trapframe *frame) 377 { 378 struct globaldata *gd = mycpu; 379 struct thread *td = gd->gd_curthread; 380 struct lwp *lp = td->td_lwp; 381 struct proc *p; 382 int sticks = 0; 383 int i = 0, ucode = 0, type, code; 384 int have_mplock = 0; 385 #ifdef INVARIANTS 386 int crit_count = td->td_critcount; 387 lwkt_tokref_t curstop = td->td_toks_stop; 388 #endif 389 vm_offset_t eva; 390 391 p = td->td_proc; 392 393 if (frame->tf_trapno == T_PAGEFLT) 394 eva = frame->tf_addr; 395 else 396 eva = 0; 397 #if 0 398 kprintf("USER_TRAP AT %08lx xflags %ld trapno %ld eva %08lx\n", 399 frame->tf_rip, frame->tf_xflags, frame->tf_trapno, eva); 400 #endif 401 402 /* 403 * Everything coming from user mode runs through user_trap, 404 * including system calls. 405 */ 406 if (frame->tf_trapno == T_FAST_SYSCALL) { 407 syscall2(frame); 408 return; 409 } 410 411 KTR_LOG(kernentry_trap, lp->lwp_proc->p_pid, lp->lwp_tid, 412 frame->tf_trapno, eva); 413 414 #ifdef DDB 415 if (db_active) { 416 eva = (frame->tf_trapno == T_PAGEFLT ? rcr2() : 0); 417 ++gd->gd_trap_nesting_level; 418 MAKEMPSAFE(have_mplock); 419 trap_fatal(frame, TRUE, eva); 420 --gd->gd_trap_nesting_level; 421 goto out2; 422 } 423 #endif 424 425 type = frame->tf_trapno; 426 code = frame->tf_err; 427 428 userenter(td, p); 429 430 sticks = (int)td->td_sticks; 431 lp->lwp_md.md_regs = frame; 432 433 switch (type) { 434 case T_PRIVINFLT: /* privileged instruction fault */ 435 i = SIGILL; 436 ucode = ILL_PRVOPC; 437 break; 438 439 case T_BPTFLT: /* bpt instruction fault */ 440 case T_TRCTRAP: /* trace trap */ 441 frame->tf_rflags &= ~PSL_T; 442 i = SIGTRAP; 443 ucode = (type == T_TRCTRAP ? TRAP_TRACE : TRAP_BRKPT); 444 break; 445 446 case T_ARITHTRAP: /* arithmetic trap */ 447 ucode = code; 448 i = SIGFPE; 449 break; 450 451 case T_ASTFLT: /* Allow process switch */ 452 mycpu->gd_cnt.v_soft++; 453 if (mycpu->gd_reqflags & RQF_AST_OWEUPC) { 454 atomic_clear_int(&mycpu->gd_reqflags, RQF_AST_OWEUPC); 455 addupc_task(p, p->p_prof.pr_addr, p->p_prof.pr_ticks); 456 } 457 goto out; 458 459 /* 460 * The following two traps can happen in 461 * vm86 mode, and, if so, we want to handle 462 * them specially. 463 */ 464 case T_PROTFLT: /* general protection fault */ 465 case T_STKFLT: /* stack fault */ 466 #if 0 467 if (frame->tf_eflags & PSL_VM) { 468 i = vm86_emulate((struct vm86frame *)frame); 469 if (i == 0) 470 goto out; 471 break; 472 } 473 #endif 474 /* FALL THROUGH */ 475 476 case T_SEGNPFLT: /* segment not present fault */ 477 case T_TSSFLT: /* invalid TSS fault */ 478 case T_DOUBLEFLT: /* double fault */ 479 default: 480 i = SIGBUS; 481 ucode = code + BUS_SEGM_FAULT ; 482 break; 483 484 case T_PAGEFLT: /* page fault */ 485 MAKEMPSAFE(have_mplock); 486 i = trap_pfault(frame, TRUE, eva); 487 if (i == -1 || i == 0) 488 goto out; 489 490 491 if (i == SIGSEGV) 492 ucode = SEGV_MAPERR; 493 else { 494 i = SIGSEGV; 495 ucode = SEGV_ACCERR; 496 } 497 break; 498 499 case T_DIVIDE: /* integer divide fault */ 500 ucode = FPE_INTDIV; 501 i = SIGFPE; 502 break; 503 504 #if NISA > 0 505 case T_NMI: 506 MAKEMPSAFE(have_mplock); 507 /* machine/parity/power fail/"kitchen sink" faults */ 508 if (isa_nmi(code) == 0) { 509 #ifdef DDB 510 /* 511 * NMI can be hooked up to a pushbutton 512 * for debugging. 513 */ 514 if (ddb_on_nmi) { 515 kprintf ("NMI ... going to debugger\n"); 516 kdb_trap(type, 0, frame); 517 } 518 #endif /* DDB */ 519 goto out2; 520 } else if (panic_on_nmi) 521 panic("NMI indicates hardware failure"); 522 break; 523 #endif /* NISA > 0 */ 524 525 case T_OFLOW: /* integer overflow fault */ 526 ucode = FPE_INTOVF; 527 i = SIGFPE; 528 break; 529 530 case T_BOUND: /* bounds check fault */ 531 ucode = FPE_FLTSUB; 532 i = SIGFPE; 533 break; 534 535 case T_DNA: 536 /* 537 * Virtual kernel intercept - pass the DNA exception 538 * to the (emulated) virtual kernel if it asked to handle 539 * it. This occurs when the virtual kernel is holding 540 * onto the FP context for a different emulated 541 * process then the one currently running. 542 * 543 * We must still call npxdna() since we may have 544 * saved FP state that the (emulated) virtual kernel 545 * needs to hand over to a different emulated process. 546 */ 547 if (lp->lwp_vkernel && lp->lwp_vkernel->ve && 548 (td->td_pcb->pcb_flags & FP_VIRTFP) 549 ) { 550 npxdna(frame); 551 break; 552 } 553 554 /* 555 * The kernel may have switched out the FP unit's 556 * state, causing the user process to take a fault 557 * when it tries to use the FP unit. Restore the 558 * state here 559 */ 560 if (npxdna(frame)) 561 goto out; 562 if (!pmath_emulate) { 563 i = SIGFPE; 564 ucode = FPE_FPU_NP_TRAP; 565 break; 566 } 567 i = (*pmath_emulate)(frame); 568 if (i == 0) { 569 if (!(frame->tf_rflags & PSL_T)) 570 goto out2; 571 frame->tf_rflags &= ~PSL_T; 572 i = SIGTRAP; 573 } 574 /* else ucode = emulator_only_knows() XXX */ 575 break; 576 577 case T_FPOPFLT: /* FPU operand fetch fault */ 578 ucode = T_FPOPFLT; 579 i = SIGILL; 580 break; 581 582 case T_XMMFLT: /* SIMD floating-point exception */ 583 ucode = 0; /* XXX */ 584 i = SIGFPE; 585 break; 586 } 587 588 /* 589 * Virtual kernel intercept - if the fault is directly related to a 590 * VM context managed by a virtual kernel then let the virtual kernel 591 * handle it. 592 */ 593 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) { 594 vkernel_trap(lp, frame); 595 goto out; 596 } 597 598 /* 599 * Translate fault for emulators (e.g. Linux) 600 */ 601 if (*p->p_sysent->sv_transtrap) 602 i = (*p->p_sysent->sv_transtrap)(i, type); 603 604 MAKEMPSAFE(have_mplock); 605 trapsignal(lp, i, ucode); 606 607 #ifdef DEBUG 608 if (type <= MAX_TRAP_MSG) { 609 uprintf("fatal process exception: %s", 610 trap_msg[type]); 611 if ((type == T_PAGEFLT) || (type == T_PROTFLT)) 612 uprintf(", fault VA = 0x%lx", (u_long)eva); 613 uprintf("\n"); 614 } 615 #endif 616 617 out: 618 userret(lp, frame, sticks); 619 userexit(lp); 620 out2: ; 621 if (have_mplock) 622 rel_mplock(); 623 KTR_LOG(kernentry_trap_ret, lp->lwp_proc->p_pid, lp->lwp_tid); 624 #ifdef INVARIANTS 625 KASSERT(crit_count == td->td_critcount, 626 ("trap: critical section count mismatch! %d/%d", 627 crit_count, td->td_pri)); 628 KASSERT(curstop == td->td_toks_stop, 629 ("trap: extra tokens held after trap! %ld/%ld", 630 curstop - &td->td_toks_base, 631 td->td_toks_stop - &td->td_toks_base)); 632 #endif 633 } 634 635 void 636 kern_trap(struct trapframe *frame) 637 { 638 struct globaldata *gd = mycpu; 639 struct thread *td = gd->gd_curthread; 640 struct lwp *lp; 641 struct proc *p; 642 int i = 0, ucode = 0, type, code; 643 int have_mplock = 0; 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 if (have_mplock) 826 rel_mplock(); 827 #ifdef INVARIANTS 828 KASSERT(crit_count == td->td_critcount, 829 ("trap: critical section count mismatch! %d/%d", 830 crit_count, td->td_pri)); 831 KASSERT(curstop == td->td_toks_stop, 832 ("trap: extra tokens held after trap! %ld/%ld", 833 curstop - &td->td_toks_base, 834 td->td_toks_stop - &td->td_toks_base)); 835 #endif 836 } 837 838 int 839 trap_pfault(struct trapframe *frame, int usermode, vm_offset_t eva) 840 { 841 vm_offset_t va; 842 struct vmspace *vm = NULL; 843 vm_map_t map = 0; 844 int rv = 0; 845 vm_prot_t ftype; 846 thread_t td = curthread; 847 struct lwp *lp = td->td_lwp; 848 int fault_flags; 849 850 va = trunc_page(eva); 851 if (usermode == FALSE) { 852 /* 853 * This is a fault on kernel virtual memory. 854 */ 855 map = &kernel_map; 856 } else { 857 /* 858 * This is a fault on non-kernel virtual memory. 859 * vm is initialized above to NULL. If curproc is NULL 860 * or curproc->p_vmspace is NULL the fault is fatal. 861 */ 862 if (lp != NULL) 863 vm = lp->lwp_vmspace; 864 865 if (vm == NULL) 866 goto nogo; 867 868 map = &vm->vm_map; 869 } 870 871 if (frame->tf_err & PGEX_W) 872 ftype = VM_PROT_READ | VM_PROT_WRITE; 873 else 874 ftype = VM_PROT_READ; 875 876 if (map != &kernel_map) { 877 /* 878 * Keep swapout from messing with us during this 879 * critical time. 880 */ 881 PHOLD(lp->lwp_proc); 882 883 /* 884 * Grow the stack if necessary 885 */ 886 /* grow_stack returns false only if va falls into 887 * a growable stack region and the stack growth 888 * fails. It returns true if va was not within 889 * a growable stack region, or if the stack 890 * growth succeeded. 891 */ 892 if (!grow_stack (lp->lwp_proc, va)) { 893 rv = KERN_FAILURE; 894 PRELE(lp->lwp_proc); 895 goto nogo; 896 } 897 898 fault_flags = 0; 899 if (usermode) 900 fault_flags |= VM_FAULT_BURST; 901 if (ftype & VM_PROT_WRITE) 902 fault_flags |= VM_FAULT_DIRTY; 903 else 904 fault_flags |= VM_FAULT_NORMAL; 905 rv = vm_fault(map, va, ftype, fault_flags); 906 907 PRELE(lp->lwp_proc); 908 } else { 909 /* 910 * Don't have to worry about process locking or stacks in the kernel. 911 */ 912 rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL); 913 } 914 915 if (rv == KERN_SUCCESS) 916 return (0); 917 nogo: 918 if (!usermode) { 919 if (td->td_gd->gd_intr_nesting_level == 0 && 920 td->td_pcb->pcb_onfault) { 921 frame->tf_rip = (register_t)td->td_pcb->pcb_onfault; 922 return (0); 923 } 924 trap_fatal(frame, usermode, eva); 925 return (-1); 926 } 927 928 /* 929 * NOTE: on x86_64 we have a tf_addr field in the trapframe, no 930 * kludge is needed to pass the fault address to signal handlers. 931 */ 932 struct proc *p = td->td_proc; 933 kprintf("seg-fault accessing address %p rip=%p pid=%d p_comm=%s\n", 934 (void *)va, (void *)frame->tf_rip, p->p_pid, p->p_comm); 935 /* Debugger("seg-fault"); */ 936 937 return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV); 938 } 939 940 static void 941 trap_fatal(struct trapframe *frame, int usermode, vm_offset_t eva) 942 { 943 int code, type, ss; 944 long rsp; 945 946 code = frame->tf_xflags; 947 type = frame->tf_trapno; 948 949 if (type <= MAX_TRAP_MSG) { 950 kprintf("\n\nFatal trap %d: %s while in %s mode\n", 951 type, trap_msg[type], 952 (usermode ? "user" : "kernel")); 953 } 954 /* two separate prints in case of a trap on an unmapped page */ 955 kprintf("cpuid = %d\n", mycpu->gd_cpuid); 956 if (type == T_PAGEFLT) { 957 kprintf("fault virtual address = %p\n", (void *)eva); 958 kprintf("fault code = %s %s, %s\n", 959 usermode ? "user" : "supervisor", 960 code & PGEX_W ? "write" : "read", 961 code & PGEX_P ? "protection violation" : "page not present"); 962 } 963 kprintf("instruction pointer = 0x%lx:0x%lx\n", 964 frame->tf_cs & 0xffff, frame->tf_rip); 965 if (usermode) { 966 ss = frame->tf_ss & 0xffff; 967 rsp = frame->tf_rsp; 968 } else { 969 ss = GSEL(GDATA_SEL, SEL_KPL); 970 rsp = (long)&frame->tf_rsp; 971 } 972 kprintf("stack pointer = 0x%x:0x%lx\n", ss, rsp); 973 kprintf("frame pointer = 0x%x:0x%lx\n", ss, frame->tf_rbp); 974 kprintf("processor eflags = "); 975 if (frame->tf_rflags & PSL_T) 976 kprintf("trace trap, "); 977 if (frame->tf_rflags & PSL_I) 978 kprintf("interrupt enabled, "); 979 if (frame->tf_rflags & PSL_NT) 980 kprintf("nested task, "); 981 if (frame->tf_rflags & PSL_RF) 982 kprintf("resume, "); 983 #if 0 984 if (frame->tf_eflags & PSL_VM) 985 kprintf("vm86, "); 986 #endif 987 kprintf("IOPL = %jd\n", (intmax_t)((frame->tf_rflags & PSL_IOPL) >> 12)); 988 kprintf("current process = "); 989 if (curproc) { 990 kprintf("%lu (%s)\n", 991 (u_long)curproc->p_pid, curproc->p_comm ? 992 curproc->p_comm : ""); 993 } else { 994 kprintf("Idle\n"); 995 } 996 kprintf("current thread = pri %d ", curthread->td_pri); 997 if (curthread->td_critcount) 998 kprintf("(CRIT)"); 999 kprintf("\n"); 1000 /** 1001 * XXX FIXME: 1002 * we probably SHOULD have stopped the other CPUs before now! 1003 * another CPU COULD have been touching cpl at this moment... 1004 */ 1005 kprintf(" <- SMP: XXX"); 1006 kprintf("\n"); 1007 1008 #ifdef KDB 1009 if (kdb_trap(&psl)) 1010 return; 1011 #endif 1012 #ifdef DDB 1013 if ((debugger_on_panic || db_active) && kdb_trap(type, code, frame)) 1014 return; 1015 #endif 1016 kprintf("trap number = %d\n", type); 1017 if (type <= MAX_TRAP_MSG) 1018 panic("%s", trap_msg[type]); 1019 else 1020 panic("unknown/reserved trap"); 1021 } 1022 1023 /* 1024 * Double fault handler. Called when a fault occurs while writing 1025 * a frame for a trap/exception onto the stack. This usually occurs 1026 * when the stack overflows (such is the case with infinite recursion, 1027 * for example). 1028 * 1029 * XXX Note that the current PTD gets replaced by IdlePTD when the 1030 * task switch occurs. This means that the stack that was active at 1031 * the time of the double fault is not available at <kstack> unless 1032 * the machine was idle when the double fault occurred. The downside 1033 * of this is that "trace <ebp>" in ddb won't work. 1034 */ 1035 void 1036 dblfault_handler(void) 1037 { 1038 #if JG 1039 struct mdglobaldata *gd = mdcpu; 1040 #endif 1041 1042 kprintf("\nFatal double fault:\n"); 1043 #if JG 1044 kprintf("rip = 0x%lx\n", gd->gd_common_tss.tss_rip); 1045 kprintf("rsp = 0x%lx\n", gd->gd_common_tss.tss_rsp); 1046 kprintf("rbp = 0x%lx\n", gd->gd_common_tss.tss_rbp); 1047 #endif 1048 /* two separate prints in case of a trap on an unmapped page */ 1049 kprintf("cpuid = %d\n", mycpu->gd_cpuid); 1050 panic("double fault"); 1051 } 1052 1053 /* 1054 * Compensate for 386 brain damage (missing URKR). 1055 * This is a little simpler than the pagefault handler in trap() because 1056 * it the page tables have already been faulted in and high addresses 1057 * are thrown out early for other reasons. 1058 */ 1059 int 1060 trapwrite(unsigned addr) 1061 { 1062 struct lwp *lp; 1063 vm_offset_t va; 1064 struct vmspace *vm; 1065 int rv; 1066 1067 va = trunc_page((vm_offset_t)addr); 1068 /* 1069 * XXX - MAX is END. Changed > to >= for temp. fix. 1070 */ 1071 if (va >= VM_MAX_USER_ADDRESS) 1072 return (1); 1073 1074 lp = curthread->td_lwp; 1075 vm = lp->lwp_vmspace; 1076 1077 PHOLD(lp->lwp_proc); 1078 1079 if (!grow_stack (lp->lwp_proc, va)) { 1080 PRELE(lp->lwp_proc); 1081 return (1); 1082 } 1083 1084 /* 1085 * fault the data page 1086 */ 1087 rv = vm_fault(&vm->vm_map, va, VM_PROT_WRITE, VM_FAULT_DIRTY); 1088 1089 PRELE(lp->lwp_proc); 1090 1091 if (rv != KERN_SUCCESS) 1092 return 1; 1093 1094 return (0); 1095 } 1096 1097 /* 1098 * syscall2 - MP aware system call request C handler 1099 * 1100 * A system call is essentially treated as a trap except that the 1101 * MP lock is not held on entry or return. We are responsible for 1102 * obtaining the MP lock if necessary and for handling ASTs 1103 * (e.g. a task switch) prior to return. 1104 * 1105 * In general, only simple access and manipulation of curproc and 1106 * the current stack is allowed without having to hold MP lock. 1107 * 1108 * MPSAFE - note that large sections of this routine are run without 1109 * the MP lock. 1110 */ 1111 void 1112 syscall2(struct trapframe *frame) 1113 { 1114 struct thread *td = curthread; 1115 struct proc *p = td->td_proc; 1116 struct lwp *lp = td->td_lwp; 1117 caddr_t params; 1118 struct sysent *callp; 1119 register_t orig_tf_rflags; 1120 int sticks; 1121 int error; 1122 int narg; 1123 #ifdef INVARIANTS 1124 int crit_count = td->td_critcount; 1125 lwkt_tokref_t curstop = td->td_toks_stop; 1126 #endif 1127 int have_mplock = 0; 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_rax); 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 /* 1330 * Release the MP lock if we had to get it 1331 */ 1332 if (have_mplock) 1333 rel_mplock(); 1334 KTR_LOG(kernentry_syscall_ret, lp->lwp_proc->p_pid, lp->lwp_tid, error); 1335 #ifdef INVARIANTS 1336 KASSERT(&td->td_toks_base == td->td_toks_stop, 1337 ("syscall: critical section count mismatch! %d/%d", 1338 crit_count, td->td_pri)); 1339 KASSERT(curstop == td->td_toks_stop, 1340 ("syscall: extra tokens held after trap! %ld", 1341 td->td_toks_stop - &td->td_toks_base)); 1342 #endif 1343 } 1344 1345 /* 1346 * NOTE: mplock not held at any point 1347 */ 1348 void 1349 fork_return(struct lwp *lp, struct trapframe *frame) 1350 { 1351 frame->tf_rax = 0; /* Child returns zero */ 1352 frame->tf_rflags &= ~PSL_C; /* success */ 1353 frame->tf_rdx = 1; 1354 1355 generic_lwp_return(lp, frame); 1356 KTR_LOG(kernentry_fork_ret, lp->lwp_proc->p_pid, lp->lwp_tid); 1357 } 1358 1359 /* 1360 * Simplified back end of syscall(), used when returning from fork() 1361 * directly into user mode. 1362 * 1363 * This code will return back into the fork trampoline code which then 1364 * runs doreti. 1365 * 1366 * NOTE: The mplock is not held at any point. 1367 */ 1368 void 1369 generic_lwp_return(struct lwp *lp, struct trapframe *frame) 1370 { 1371 struct proc *p = lp->lwp_proc; 1372 1373 /* 1374 * Newly forked processes are given a kernel priority. We have to 1375 * adjust the priority to a normal user priority and fake entry 1376 * into the kernel (call userenter()) to install a passive release 1377 * function just in case userret() decides to stop the process. This 1378 * can occur when ^Z races a fork. If we do not install the passive 1379 * release function the current process designation will not be 1380 * released when the thread goes to sleep. 1381 */ 1382 lwkt_setpri_self(TDPRI_USER_NORM); 1383 userenter(lp->lwp_thread, p); 1384 userret(lp, frame, 0); 1385 #ifdef KTRACE 1386 if (KTRPOINT(lp->lwp_thread, KTR_SYSRET)) 1387 ktrsysret(lp, SYS_fork, 0, 0); 1388 #endif 1389 lp->lwp_flags |= LWP_PASSIVE_ACQ; 1390 userexit(lp); 1391 lp->lwp_flags &= ~LWP_PASSIVE_ACQ; 1392 } 1393 1394 /* 1395 * doreti has turned into this. The frame is directly on the stack. We 1396 * pull everything else we need (fpu and tls context) from the current 1397 * thread. 1398 * 1399 * Note on fpu interactions: In a virtual kernel, the fpu context for 1400 * an emulated user mode process is not shared with the virtual kernel's 1401 * fpu context, so we only have to 'stack' fpu contexts within the virtual 1402 * kernel itself, and not even then since the signal() contexts that we care 1403 * about save and restore the FPU state (I think anyhow). 1404 * 1405 * vmspace_ctl() returns an error only if it had problems instaling the 1406 * context we supplied or problems copying data to/from our VM space. 1407 */ 1408 void 1409 go_user(struct intrframe *frame) 1410 { 1411 struct trapframe *tf = (void *)&frame->if_rdi; 1412 int r; 1413 1414 /* 1415 * Interrupts may be disabled on entry, make sure all signals 1416 * can be received before beginning our loop. 1417 */ 1418 sigsetmask(0); 1419 1420 /* 1421 * Switch to the current simulated user process, then call 1422 * user_trap() when we break out of it (usually due to a signal). 1423 */ 1424 for (;;) { 1425 /* 1426 * Tell the real kernel whether it is ok to use the FP 1427 * unit or not. 1428 */ 1429 if (mdcpu->gd_npxthread == curthread) { 1430 tf->tf_xflags &= ~PGEX_FPFAULT; 1431 } else { 1432 tf->tf_xflags |= PGEX_FPFAULT; 1433 } 1434 1435 /* 1436 * Run emulated user process context. This call interlocks 1437 * with new mailbox signals. 1438 * 1439 * Set PGEX_U unconditionally, indicating a user frame (the 1440 * bit is normally set only by T_PAGEFLT). 1441 */ 1442 r = vmspace_ctl(&curproc->p_vmspace->vm_pmap, VMSPACE_CTL_RUN, 1443 tf, &curthread->td_savevext); 1444 frame->if_xflags |= PGEX_U; 1445 #if 0 1446 kprintf("GO USER %d trap %ld EVA %08lx RIP %08lx RSP %08lx XFLAGS %02lx/%02lx\n", 1447 r, tf->tf_trapno, tf->tf_addr, tf->tf_rip, tf->tf_rsp, 1448 tf->tf_xflags, frame->if_xflags); 1449 #endif 1450 if (r < 0) { 1451 if (errno != EINTR) 1452 panic("vmspace_ctl failed error %d", errno); 1453 } else { 1454 if (tf->tf_trapno) { 1455 user_trap(tf); 1456 } 1457 } 1458 if (mycpu->gd_reqflags & RQF_AST_MASK) { 1459 tf->tf_trapno = T_ASTFLT; 1460 user_trap(tf); 1461 } 1462 tf->tf_trapno = 0; 1463 } 1464 } 1465 1466 /* 1467 * If PGEX_FPFAULT is set then set FP_VIRTFP in the PCB to force a T_DNA 1468 * fault (which is then passed back to the virtual kernel) if an attempt is 1469 * made to use the FP unit. 1470 * 1471 * XXX this is a fairly big hack. 1472 */ 1473 void 1474 set_vkernel_fp(struct trapframe *frame) 1475 { 1476 struct thread *td = curthread; 1477 1478 if (frame->tf_xflags & PGEX_FPFAULT) { 1479 td->td_pcb->pcb_flags |= FP_VIRTFP; 1480 if (mdcpu->gd_npxthread == td) 1481 npxexit(); 1482 } else { 1483 td->td_pcb->pcb_flags &= ~FP_VIRTFP; 1484 } 1485 } 1486 1487 /* 1488 * Called from vkernel_trap() to fixup the vkernel's syscall 1489 * frame for vmspace_ctl() return. 1490 */ 1491 void 1492 cpu_vkernel_trap(struct trapframe *frame, int error) 1493 { 1494 frame->tf_rax = error; 1495 if (error) 1496 frame->tf_rflags |= PSL_C; 1497 else 1498 frame->tf_rflags &= ~PSL_C; 1499 } 1500