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 177 * the thread 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 i = SIGILL; 440 ucode = ILL_PRVOPC; 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 ucode = (type == T_TRCTRAP ? TRAP_TRACE : TRAP_BRKPT); 448 break; 449 450 case T_ARITHTRAP: /* arithmetic trap */ 451 ucode = code; 452 i = SIGFPE; 453 break; 454 455 case T_ASTFLT: /* Allow process switch */ 456 mycpu->gd_cnt.v_soft++; 457 if (mycpu->gd_reqflags & RQF_AST_OWEUPC) { 458 atomic_clear_int(&mycpu->gd_reqflags, RQF_AST_OWEUPC); 459 addupc_task(p, p->p_prof.pr_addr, p->p_prof.pr_ticks); 460 } 461 goto out; 462 463 /* 464 * The following two traps can happen in 465 * vm86 mode, and, if so, we want to handle 466 * them specially. 467 */ 468 case T_PROTFLT: /* general protection fault */ 469 case T_STKFLT: /* stack fault */ 470 #if 0 471 if (frame->tf_eflags & PSL_VM) { 472 i = vm86_emulate((struct vm86frame *)frame); 473 if (i == 0) 474 goto out; 475 break; 476 } 477 #endif 478 /* FALL THROUGH */ 479 480 case T_SEGNPFLT: /* segment not present fault */ 481 case T_TSSFLT: /* invalid TSS fault */ 482 case T_DOUBLEFLT: /* double fault */ 483 default: 484 i = SIGBUS; 485 ucode = code + BUS_SEGM_FAULT ; 486 break; 487 488 case T_PAGEFLT: /* page fault */ 489 MAKEMPSAFE(have_mplock); 490 i = trap_pfault(frame, TRUE, eva); 491 if (i == -1 || i == 0) 492 goto out; 493 494 495 if (i == SIGSEGV) 496 ucode = SEGV_MAPERR; 497 else { 498 i = SIGSEGV; 499 ucode = SEGV_ACCERR; 500 } 501 break; 502 503 case T_DIVIDE: /* integer divide fault */ 504 ucode = FPE_INTDIV; 505 i = SIGFPE; 506 break; 507 508 #if NISA > 0 509 case T_NMI: 510 MAKEMPSAFE(have_mplock); 511 /* machine/parity/power fail/"kitchen sink" faults */ 512 if (isa_nmi(code) == 0) { 513 #ifdef DDB 514 /* 515 * NMI can be hooked up to a pushbutton 516 * for debugging. 517 */ 518 if (ddb_on_nmi) { 519 kprintf ("NMI ... going to debugger\n"); 520 kdb_trap(type, 0, frame); 521 } 522 #endif /* DDB */ 523 goto out2; 524 } else if (panic_on_nmi) 525 panic("NMI indicates hardware failure"); 526 break; 527 #endif /* NISA > 0 */ 528 529 case T_OFLOW: /* integer overflow fault */ 530 ucode = FPE_INTOVF; 531 i = SIGFPE; 532 break; 533 534 case T_BOUND: /* bounds check fault */ 535 ucode = FPE_FLTSUB; 536 i = SIGFPE; 537 break; 538 539 case T_DNA: 540 /* 541 * Virtual kernel intercept - pass the DNA exception 542 * to the (emulated) virtual kernel if it asked to handle 543 * it. This occurs when the virtual kernel is holding 544 * onto the FP context for a different emulated 545 * process then the one currently running. 546 * 547 * We must still call npxdna() since we may have 548 * saved FP state that the (emulated) virtual kernel 549 * needs to hand over to a different emulated process. 550 */ 551 if (lp->lwp_vkernel && lp->lwp_vkernel->ve && 552 (td->td_pcb->pcb_flags & FP_VIRTFP) 553 ) { 554 npxdna(frame); 555 break; 556 } 557 558 /* 559 * The kernel may have switched out the FP unit's 560 * state, causing the user process to take a fault 561 * when it tries to use the FP unit. Restore the 562 * state here 563 */ 564 if (npxdna(frame)) 565 goto out; 566 if (!pmath_emulate) { 567 i = SIGFPE; 568 ucode = FPE_FPU_NP_TRAP; 569 break; 570 } 571 i = (*pmath_emulate)(frame); 572 if (i == 0) { 573 if (!(frame->tf_rflags & PSL_T)) 574 goto out2; 575 frame->tf_rflags &= ~PSL_T; 576 i = SIGTRAP; 577 } 578 /* else ucode = emulator_only_knows() XXX */ 579 break; 580 581 case T_FPOPFLT: /* FPU operand fetch fault */ 582 ucode = T_FPOPFLT; 583 i = SIGILL; 584 break; 585 586 case T_XMMFLT: /* SIMD floating-point exception */ 587 ucode = 0; /* XXX */ 588 i = SIGFPE; 589 break; 590 } 591 592 /* 593 * Virtual kernel intercept - if the fault is directly related to a 594 * VM context managed by a virtual kernel then let the virtual kernel 595 * handle it. 596 */ 597 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) { 598 vkernel_trap(lp, frame); 599 goto out; 600 } 601 602 /* 603 * Translate fault for emulators (e.g. Linux) 604 */ 605 if (*p->p_sysent->sv_transtrap) 606 i = (*p->p_sysent->sv_transtrap)(i, type); 607 608 MAKEMPSAFE(have_mplock); 609 trapsignal(lp, i, ucode); 610 611 #ifdef DEBUG 612 if (type <= MAX_TRAP_MSG) { 613 uprintf("fatal process exception: %s", 614 trap_msg[type]); 615 if ((type == T_PAGEFLT) || (type == T_PROTFLT)) 616 uprintf(", fault VA = 0x%lx", (u_long)eva); 617 uprintf("\n"); 618 } 619 #endif 620 621 out: 622 userret(lp, frame, sticks); 623 userexit(lp); 624 out2: ; 625 #ifdef SMP 626 if (have_mplock) 627 rel_mplock(); 628 #endif 629 KTR_LOG(kernentry_trap_ret, lp->lwp_proc->p_pid, lp->lwp_tid); 630 #ifdef INVARIANTS 631 KASSERT(crit_count == td->td_critcount, 632 ("trap: critical section count mismatch! %d/%d", 633 crit_count, td->td_pri)); 634 KASSERT(curstop == td->td_toks_stop, 635 ("trap: extra tokens held after trap! %ld/%ld", 636 curstop - &td->td_toks_base, 637 td->td_toks_stop - &td->td_toks_base)); 638 #endif 639 } 640 641 void 642 kern_trap(struct trapframe *frame) 643 { 644 struct globaldata *gd = mycpu; 645 struct thread *td = gd->gd_curthread; 646 struct lwp *lp; 647 struct proc *p; 648 int i = 0, ucode = 0, type, code; 649 #ifdef SMP 650 int have_mplock = 0; 651 #endif 652 #ifdef INVARIANTS 653 int crit_count = td->td_critcount; 654 lwkt_tokref_t curstop = td->td_toks_stop; 655 #endif 656 vm_offset_t eva; 657 658 lp = td->td_lwp; 659 p = td->td_proc; 660 661 if (frame->tf_trapno == T_PAGEFLT) 662 eva = frame->tf_addr; 663 else 664 eva = 0; 665 666 #ifdef DDB 667 if (db_active) { 668 ++gd->gd_trap_nesting_level; 669 MAKEMPSAFE(have_mplock); 670 trap_fatal(frame, FALSE, eva); 671 --gd->gd_trap_nesting_level; 672 goto out2; 673 } 674 #endif 675 676 type = frame->tf_trapno; 677 code = frame->tf_err; 678 679 #if 0 680 kernel_trap: 681 #endif 682 /* kernel trap */ 683 684 switch (type) { 685 case T_PAGEFLT: /* page fault */ 686 MAKEMPSAFE(have_mplock); 687 trap_pfault(frame, FALSE, eva); 688 goto out2; 689 690 case T_DNA: 691 /* 692 * The kernel may be using npx for copying or other 693 * purposes. 694 */ 695 panic("kernel NPX should not happen"); 696 if (npxdna(frame)) 697 goto out2; 698 break; 699 700 case T_PROTFLT: /* general protection fault */ 701 case T_SEGNPFLT: /* segment not present fault */ 702 /* 703 * Invalid segment selectors and out of bounds 704 * %eip's and %esp's can be set up in user mode. 705 * This causes a fault in kernel mode when the 706 * kernel tries to return to user mode. We want 707 * to get this fault so that we can fix the 708 * problem here and not have to check all the 709 * selectors and pointers when the user changes 710 * them. 711 */ 712 if (mycpu->gd_intr_nesting_level == 0) { 713 if (td->td_pcb->pcb_onfault) { 714 frame->tf_rip = 715 (register_t)td->td_pcb->pcb_onfault; 716 goto out2; 717 } 718 } 719 break; 720 721 case T_TSSFLT: 722 /* 723 * PSL_NT can be set in user mode and isn't cleared 724 * automatically when the kernel is entered. This 725 * causes a TSS fault when the kernel attempts to 726 * `iret' because the TSS link is uninitialized. We 727 * want to get this fault so that we can fix the 728 * problem here and not every time the kernel is 729 * entered. 730 */ 731 if (frame->tf_rflags & PSL_NT) { 732 frame->tf_rflags &= ~PSL_NT; 733 goto out2; 734 } 735 break; 736 737 case T_TRCTRAP: /* trace trap */ 738 #if 0 739 if (frame->tf_eip == (int)IDTVEC(syscall)) { 740 /* 741 * We've just entered system mode via the 742 * syscall lcall. Continue single stepping 743 * silently until the syscall handler has 744 * saved the flags. 745 */ 746 goto out2; 747 } 748 if (frame->tf_eip == (int)IDTVEC(syscall) + 1) { 749 /* 750 * The syscall handler has now saved the 751 * flags. Stop single stepping it. 752 */ 753 frame->tf_eflags &= ~PSL_T; 754 goto out2; 755 } 756 #endif 757 #if 0 758 /* 759 * Ignore debug register trace traps due to 760 * accesses in the user's address space, which 761 * can happen under several conditions such as 762 * if a user sets a watchpoint on a buffer and 763 * then passes that buffer to a system call. 764 * We still want to get TRCTRAPS for addresses 765 * in kernel space because that is useful when 766 * debugging the kernel. 767 */ 768 if (user_dbreg_trap()) { 769 /* 770 * Reset breakpoint bits because the 771 * processor doesn't 772 */ 773 load_dr6(rdr6() & 0xfffffff0); 774 goto out2; 775 } 776 #endif 777 /* 778 * Fall through (TRCTRAP kernel mode, kernel address) 779 */ 780 case T_BPTFLT: 781 /* 782 * If DDB is enabled, let it handle the debugger trap. 783 * Otherwise, debugger traps "can't happen". 784 */ 785 #ifdef DDB 786 MAKEMPSAFE(have_mplock); 787 if (kdb_trap (type, 0, frame)) 788 goto out2; 789 #endif 790 break; 791 case T_DIVIDE: 792 MAKEMPSAFE(have_mplock); 793 trap_fatal(frame, FALSE, eva); 794 goto out2; 795 case T_NMI: 796 MAKEMPSAFE(have_mplock); 797 trap_fatal(frame, FALSE, eva); 798 goto out2; 799 case T_SYSCALL80: 800 case T_FAST_SYSCALL: 801 /* 802 * Ignore this trap generated from a spurious SIGTRAP. 803 * 804 * single stepping in / syscalls leads to spurious / SIGTRAP 805 * so ignore 806 * 807 * Haiku (c) 2007 Simon 'corecode' Schubert 808 */ 809 goto out2; 810 } 811 812 /* 813 * Translate fault for emulators (e.g. Linux) 814 */ 815 if (*p->p_sysent->sv_transtrap) 816 i = (*p->p_sysent->sv_transtrap)(i, type); 817 818 MAKEMPSAFE(have_mplock); 819 trapsignal(lp, i, ucode); 820 821 #ifdef DEBUG 822 if (type <= MAX_TRAP_MSG) { 823 uprintf("fatal process exception: %s", 824 trap_msg[type]); 825 if ((type == T_PAGEFLT) || (type == T_PROTFLT)) 826 uprintf(", fault VA = 0x%lx", (u_long)eva); 827 uprintf("\n"); 828 } 829 #endif 830 831 out2: 832 ; 833 #ifdef SMP 834 if (have_mplock) 835 rel_mplock(); 836 #endif 837 #ifdef INVARIANTS 838 KASSERT(crit_count == td->td_critcount, 839 ("trap: critical section count mismatch! %d/%d", 840 crit_count, td->td_pri)); 841 KASSERT(curstop == td->td_toks_stop, 842 ("trap: extra tokens held after trap! %ld/%ld", 843 curstop - &td->td_toks_base, 844 td->td_toks_stop - &td->td_toks_base)); 845 #endif 846 } 847 848 int 849 trap_pfault(struct trapframe *frame, int usermode, vm_offset_t eva) 850 { 851 vm_offset_t va; 852 struct vmspace *vm = NULL; 853 vm_map_t map = 0; 854 int rv = 0; 855 vm_prot_t ftype; 856 thread_t td = curthread; 857 struct lwp *lp = td->td_lwp; 858 int fault_flags; 859 860 va = trunc_page(eva); 861 if (usermode == FALSE) { 862 /* 863 * This is a fault on kernel virtual memory. 864 */ 865 map = &kernel_map; 866 } else { 867 /* 868 * This is a fault on non-kernel virtual memory. 869 * vm is initialized above to NULL. If curproc is NULL 870 * or curproc->p_vmspace is NULL the fault is fatal. 871 */ 872 if (lp != NULL) 873 vm = lp->lwp_vmspace; 874 875 if (vm == NULL) 876 goto nogo; 877 878 map = &vm->vm_map; 879 } 880 881 if (frame->tf_err & PGEX_W) 882 ftype = VM_PROT_READ | VM_PROT_WRITE; 883 else 884 ftype = VM_PROT_READ; 885 886 if (map != &kernel_map) { 887 /* 888 * Keep swapout from messing with us during this 889 * critical time. 890 */ 891 PHOLD(lp->lwp_proc); 892 893 /* 894 * Grow the stack if necessary 895 */ 896 /* grow_stack returns false only if va falls into 897 * a growable stack region and the stack growth 898 * fails. It returns true if va was not within 899 * a growable stack region, or if the stack 900 * growth succeeded. 901 */ 902 if (!grow_stack (lp->lwp_proc, va)) { 903 rv = KERN_FAILURE; 904 PRELE(lp->lwp_proc); 905 goto nogo; 906 } 907 908 fault_flags = 0; 909 if (usermode) 910 fault_flags |= VM_FAULT_BURST; 911 if (ftype & VM_PROT_WRITE) 912 fault_flags |= VM_FAULT_DIRTY; 913 else 914 fault_flags |= VM_FAULT_NORMAL; 915 rv = vm_fault(map, va, ftype, fault_flags); 916 917 PRELE(lp->lwp_proc); 918 } else { 919 /* 920 * Don't have to worry about process locking or stacks in the kernel. 921 */ 922 rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL); 923 } 924 925 if (rv == KERN_SUCCESS) 926 return (0); 927 nogo: 928 if (!usermode) { 929 if (td->td_gd->gd_intr_nesting_level == 0 && 930 td->td_pcb->pcb_onfault) { 931 frame->tf_rip = (register_t)td->td_pcb->pcb_onfault; 932 return (0); 933 } 934 trap_fatal(frame, usermode, eva); 935 return (-1); 936 } 937 938 /* 939 * NOTE: on x86_64 we have a tf_addr field in the trapframe, no 940 * kludge is needed to pass the fault address to signal handlers. 941 */ 942 struct proc *p = td->td_proc; 943 kprintf("seg-fault accessing address %p rip=%p pid=%d p_comm=%s\n", 944 (void *)va, (void *)frame->tf_rip, p->p_pid, p->p_comm); 945 /* Debugger("seg-fault"); */ 946 947 return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV); 948 } 949 950 static void 951 trap_fatal(struct trapframe *frame, int usermode, vm_offset_t eva) 952 { 953 int code, type, ss; 954 long rsp; 955 956 code = frame->tf_xflags; 957 type = frame->tf_trapno; 958 959 if (type <= MAX_TRAP_MSG) { 960 kprintf("\n\nFatal trap %d: %s while in %s mode\n", 961 type, trap_msg[type], 962 (usermode ? "user" : "kernel")); 963 } 964 #ifdef SMP 965 /* two separate prints in case of a trap on an unmapped page */ 966 kprintf("cpuid = %d\n", mycpu->gd_cpuid); 967 #endif 968 if (type == T_PAGEFLT) { 969 kprintf("fault virtual address = %p\n", (void *)eva); 970 kprintf("fault code = %s %s, %s\n", 971 usermode ? "user" : "supervisor", 972 code & PGEX_W ? "write" : "read", 973 code & PGEX_P ? "protection violation" : "page not present"); 974 } 975 kprintf("instruction pointer = 0x%lx:0x%lx\n", 976 frame->tf_cs & 0xffff, frame->tf_rip); 977 if (usermode) { 978 ss = frame->tf_ss & 0xffff; 979 rsp = frame->tf_rsp; 980 } else { 981 ss = GSEL(GDATA_SEL, SEL_KPL); 982 rsp = (long)&frame->tf_rsp; 983 } 984 kprintf("stack pointer = 0x%x:0x%lx\n", ss, rsp); 985 kprintf("frame pointer = 0x%x:0x%lx\n", ss, frame->tf_rbp); 986 kprintf("processor eflags = "); 987 if (frame->tf_rflags & PSL_T) 988 kprintf("trace trap, "); 989 if (frame->tf_rflags & PSL_I) 990 kprintf("interrupt enabled, "); 991 if (frame->tf_rflags & PSL_NT) 992 kprintf("nested task, "); 993 if (frame->tf_rflags & PSL_RF) 994 kprintf("resume, "); 995 #if 0 996 if (frame->tf_eflags & PSL_VM) 997 kprintf("vm86, "); 998 #endif 999 kprintf("IOPL = %jd\n", (intmax_t)((frame->tf_rflags & PSL_IOPL) >> 12)); 1000 kprintf("current process = "); 1001 if (curproc) { 1002 kprintf("%lu (%s)\n", 1003 (u_long)curproc->p_pid, curproc->p_comm ? 1004 curproc->p_comm : ""); 1005 } else { 1006 kprintf("Idle\n"); 1007 } 1008 kprintf("current thread = pri %d ", curthread->td_pri); 1009 if (curthread->td_critcount) 1010 kprintf("(CRIT)"); 1011 kprintf("\n"); 1012 #ifdef SMP 1013 /** 1014 * XXX FIXME: 1015 * we probably SHOULD have stopped the other CPUs before now! 1016 * another CPU COULD have been touching cpl at this moment... 1017 */ 1018 kprintf(" <- SMP: XXX"); 1019 #endif 1020 kprintf("\n"); 1021 1022 #ifdef KDB 1023 if (kdb_trap(&psl)) 1024 return; 1025 #endif 1026 #ifdef DDB 1027 if ((debugger_on_panic || db_active) && kdb_trap(type, code, frame)) 1028 return; 1029 #endif 1030 kprintf("trap number = %d\n", type); 1031 if (type <= MAX_TRAP_MSG) 1032 panic("%s", trap_msg[type]); 1033 else 1034 panic("unknown/reserved trap"); 1035 } 1036 1037 /* 1038 * Double fault handler. Called when a fault occurs while writing 1039 * a frame for a trap/exception onto the stack. This usually occurs 1040 * when the stack overflows (such is the case with infinite recursion, 1041 * for example). 1042 * 1043 * XXX Note that the current PTD gets replaced by IdlePTD when the 1044 * task switch occurs. This means that the stack that was active at 1045 * the time of the double fault is not available at <kstack> unless 1046 * the machine was idle when the double fault occurred. The downside 1047 * of this is that "trace <ebp>" in ddb won't work. 1048 */ 1049 void 1050 dblfault_handler(void) 1051 { 1052 #if JG 1053 struct mdglobaldata *gd = mdcpu; 1054 #endif 1055 1056 kprintf("\nFatal double fault:\n"); 1057 #if JG 1058 kprintf("rip = 0x%lx\n", gd->gd_common_tss.tss_rip); 1059 kprintf("rsp = 0x%lx\n", gd->gd_common_tss.tss_rsp); 1060 kprintf("rbp = 0x%lx\n", gd->gd_common_tss.tss_rbp); 1061 #endif 1062 #ifdef SMP 1063 /* two separate prints in case of a trap on an unmapped page */ 1064 kprintf("cpuid = %d\n", mycpu->gd_cpuid); 1065 #endif 1066 panic("double fault"); 1067 } 1068 1069 /* 1070 * Compensate for 386 brain damage (missing URKR). 1071 * This is a little simpler than the pagefault handler in trap() because 1072 * it the page tables have already been faulted in and high addresses 1073 * are thrown out early for other reasons. 1074 */ 1075 int 1076 trapwrite(unsigned addr) 1077 { 1078 struct lwp *lp; 1079 vm_offset_t va; 1080 struct vmspace *vm; 1081 int rv; 1082 1083 va = trunc_page((vm_offset_t)addr); 1084 /* 1085 * XXX - MAX is END. Changed > to >= for temp. fix. 1086 */ 1087 if (va >= VM_MAX_USER_ADDRESS) 1088 return (1); 1089 1090 lp = curthread->td_lwp; 1091 vm = lp->lwp_vmspace; 1092 1093 PHOLD(lp->lwp_proc); 1094 1095 if (!grow_stack (lp->lwp_proc, va)) { 1096 PRELE(lp->lwp_proc); 1097 return (1); 1098 } 1099 1100 /* 1101 * fault the data page 1102 */ 1103 rv = vm_fault(&vm->vm_map, va, VM_PROT_WRITE, VM_FAULT_DIRTY); 1104 1105 PRELE(lp->lwp_proc); 1106 1107 if (rv != KERN_SUCCESS) 1108 return 1; 1109 1110 return (0); 1111 } 1112 1113 /* 1114 * syscall2 - MP aware system call request C handler 1115 * 1116 * A system call is essentially treated as a trap except that the 1117 * MP lock is not held on entry or return. We are responsible for 1118 * obtaining the MP lock if necessary and for handling ASTs 1119 * (e.g. a task switch) prior to return. 1120 * 1121 * In general, only simple access and manipulation of curproc and 1122 * the current stack is allowed without having to hold MP lock. 1123 * 1124 * MPSAFE - note that large sections of this routine are run without 1125 * the MP lock. 1126 */ 1127 void 1128 syscall2(struct trapframe *frame) 1129 { 1130 struct thread *td = curthread; 1131 struct proc *p = td->td_proc; 1132 struct lwp *lp = td->td_lwp; 1133 caddr_t params; 1134 struct sysent *callp; 1135 register_t orig_tf_rflags; 1136 int sticks; 1137 int error; 1138 int narg; 1139 #ifdef INVARIANTS 1140 int crit_count = td->td_critcount; 1141 lwkt_tokref_t curstop = td->td_toks_stop; 1142 #endif 1143 #ifdef SMP 1144 int have_mplock = 0; 1145 #endif 1146 register_t *argp; 1147 u_int code; 1148 int reg, regcnt; 1149 union sysunion args; 1150 register_t *argsdst; 1151 1152 mycpu->gd_cnt.v_syscall++; 1153 1154 KTR_LOG(kernentry_syscall, lp->lwp_proc->p_pid, lp->lwp_tid, 1155 frame->tf_rax); 1156 1157 userenter(td, p); /* lazy raise our priority */ 1158 1159 reg = 0; 1160 regcnt = 6; 1161 /* 1162 * Misc 1163 */ 1164 sticks = (int)td->td_sticks; 1165 orig_tf_rflags = frame->tf_rflags; 1166 1167 /* 1168 * Virtual kernel intercept - if a VM context managed by a virtual 1169 * kernel issues a system call the virtual kernel handles it, not us. 1170 * Restore the virtual kernel context and return from its system 1171 * call. The current frame is copied out to the virtual kernel. 1172 */ 1173 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) { 1174 vkernel_trap(lp, frame); 1175 error = EJUSTRETURN; 1176 goto out; 1177 } 1178 1179 /* 1180 * Get the system call parameters and account for time 1181 */ 1182 lp->lwp_md.md_regs = frame; 1183 params = (caddr_t)frame->tf_rsp + sizeof(register_t); 1184 code = frame->tf_rax; 1185 1186 if (p->p_sysent->sv_prepsyscall) { 1187 (*p->p_sysent->sv_prepsyscall)( 1188 frame, (int *)(&args.nosys.sysmsg + 1), 1189 &code, ¶ms); 1190 } else { 1191 if (code == SYS_syscall || code == SYS___syscall) { 1192 code = frame->tf_rdi; 1193 reg++; 1194 regcnt--; 1195 } 1196 } 1197 1198 if (p->p_sysent->sv_mask) 1199 code &= p->p_sysent->sv_mask; 1200 1201 if (code >= p->p_sysent->sv_size) 1202 callp = &p->p_sysent->sv_table[0]; 1203 else 1204 callp = &p->p_sysent->sv_table[code]; 1205 1206 narg = callp->sy_narg & SYF_ARGMASK; 1207 1208 /* 1209 * On x86_64 we get up to six arguments in registers. The rest are 1210 * on the stack. The first six members of 'struct trapframe' happen 1211 * to be the registers used to pass arguments, in exactly the right 1212 * order. 1213 */ 1214 argp = &frame->tf_rdi; 1215 argp += reg; 1216 argsdst = (register_t *)(&args.nosys.sysmsg + 1); 1217 /* 1218 * JG can we overflow the space pointed to by 'argsdst' 1219 * either with 'bcopy' or with 'copyin'? 1220 */ 1221 bcopy(argp, argsdst, sizeof(register_t) * regcnt); 1222 /* 1223 * copyin is MP aware, but the tracing code is not 1224 */ 1225 if (narg > regcnt) { 1226 KASSERT(params != NULL, ("copyin args with no params!")); 1227 error = copyin(params, &argsdst[regcnt], 1228 (narg - regcnt) * sizeof(register_t)); 1229 if (error) { 1230 #ifdef KTRACE 1231 if (KTRPOINT(td, KTR_SYSCALL)) { 1232 MAKEMPSAFE(have_mplock); 1233 1234 ktrsyscall(lp, code, narg, 1235 (void *)(&args.nosys.sysmsg + 1)); 1236 } 1237 #endif 1238 goto bad; 1239 } 1240 } 1241 1242 #ifdef KTRACE 1243 if (KTRPOINT(td, KTR_SYSCALL)) { 1244 MAKEMPSAFE(have_mplock); 1245 ktrsyscall(lp, code, narg, (void *)(&args.nosys.sysmsg + 1)); 1246 } 1247 #endif 1248 1249 /* 1250 * Default return value is 0 (will be copied to %rax). Double-value 1251 * returns use %rax and %rdx. %rdx is left unchanged for system 1252 * calls which return only one result. 1253 */ 1254 args.sysmsg_fds[0] = 0; 1255 args.sysmsg_fds[1] = frame->tf_rdx; 1256 1257 /* 1258 * The syscall might manipulate the trap frame. If it does it 1259 * will probably return EJUSTRETURN. 1260 */ 1261 args.sysmsg_frame = frame; 1262 1263 STOPEVENT(p, S_SCE, narg); /* MP aware */ 1264 1265 /* 1266 * NOTE: All system calls run MPSAFE now. The system call itself 1267 * is responsible for getting the MP lock. 1268 */ 1269 error = (*callp->sy_call)(&args); 1270 1271 #if 0 1272 kprintf("system call %d returned %d\n", code, error); 1273 #endif 1274 1275 out: 1276 /* 1277 * MP SAFE (we may or may not have the MP lock at this point) 1278 */ 1279 switch (error) { 1280 case 0: 1281 /* 1282 * Reinitialize proc pointer `p' as it may be different 1283 * if this is a child returning from fork syscall. 1284 */ 1285 p = curproc; 1286 lp = curthread->td_lwp; 1287 frame->tf_rax = args.sysmsg_fds[0]; 1288 frame->tf_rdx = args.sysmsg_fds[1]; 1289 frame->tf_rflags &= ~PSL_C; 1290 break; 1291 case ERESTART: 1292 /* 1293 * Reconstruct pc, we know that 'syscall' is 2 bytes. 1294 * We have to do a full context restore so that %r10 1295 * (which was holding the value of %rcx) is restored for 1296 * the next iteration. 1297 */ 1298 frame->tf_rip -= frame->tf_err; 1299 frame->tf_r10 = frame->tf_rcx; 1300 break; 1301 case EJUSTRETURN: 1302 break; 1303 case EASYNC: 1304 panic("Unexpected EASYNC return value (for now)"); 1305 default: 1306 bad: 1307 if (p->p_sysent->sv_errsize) { 1308 if (error >= p->p_sysent->sv_errsize) 1309 error = -1; /* XXX */ 1310 else 1311 error = p->p_sysent->sv_errtbl[error]; 1312 } 1313 frame->tf_rax = error; 1314 frame->tf_rflags |= PSL_C; 1315 break; 1316 } 1317 1318 /* 1319 * Traced syscall. trapsignal() is not MP aware. 1320 */ 1321 if (orig_tf_rflags & PSL_T) { 1322 MAKEMPSAFE(have_mplock); 1323 frame->tf_rflags &= ~PSL_T; 1324 trapsignal(lp, SIGTRAP, 0); 1325 } 1326 1327 /* 1328 * Handle reschedule and other end-of-syscall issues 1329 */ 1330 userret(lp, frame, sticks); 1331 1332 #ifdef KTRACE 1333 if (KTRPOINT(td, KTR_SYSRET)) { 1334 MAKEMPSAFE(have_mplock); 1335 ktrsysret(lp, code, error, args.sysmsg_result); 1336 } 1337 #endif 1338 1339 /* 1340 * This works because errno is findable through the 1341 * register set. If we ever support an emulation where this 1342 * is not the case, this code will need to be revisited. 1343 */ 1344 STOPEVENT(p, S_SCX, code); 1345 1346 userexit(lp); 1347 #ifdef SMP 1348 /* 1349 * Release the MP lock if we had to get it 1350 */ 1351 if (have_mplock) 1352 rel_mplock(); 1353 #endif 1354 KTR_LOG(kernentry_syscall_ret, lp->lwp_proc->p_pid, lp->lwp_tid, error); 1355 #ifdef INVARIANTS 1356 KASSERT(&td->td_toks_base == td->td_toks_stop, 1357 ("syscall: critical section count mismatch! %d/%d", 1358 crit_count, td->td_pri)); 1359 KASSERT(curstop == td->td_toks_stop, 1360 ("syscall: extra tokens held after trap! %ld", 1361 td->td_toks_stop - &td->td_toks_base)); 1362 #endif 1363 } 1364 1365 /* 1366 * NOTE: mplock not held at any point 1367 */ 1368 void 1369 fork_return(struct lwp *lp, struct trapframe *frame) 1370 { 1371 frame->tf_rax = 0; /* Child returns zero */ 1372 frame->tf_rflags &= ~PSL_C; /* success */ 1373 frame->tf_rdx = 1; 1374 1375 generic_lwp_return(lp, frame); 1376 KTR_LOG(kernentry_fork_ret, lp->lwp_proc->p_pid, lp->lwp_tid); 1377 } 1378 1379 /* 1380 * Simplified back end of syscall(), used when returning from fork() 1381 * directly into user mode. 1382 * 1383 * This code will return back into the fork trampoline code which then 1384 * runs doreti. 1385 * 1386 * NOTE: The mplock is not held at any point. 1387 */ 1388 void 1389 generic_lwp_return(struct lwp *lp, struct trapframe *frame) 1390 { 1391 struct proc *p = lp->lwp_proc; 1392 1393 /* 1394 * Newly forked processes are given a kernel priority. We have to 1395 * adjust the priority to a normal user priority and fake entry 1396 * into the kernel (call userenter()) to install a passive release 1397 * function just in case userret() decides to stop the process. This 1398 * can occur when ^Z races a fork. If we do not install the passive 1399 * release function the current process designation will not be 1400 * released when the thread goes to sleep. 1401 */ 1402 lwkt_setpri_self(TDPRI_USER_NORM); 1403 userenter(lp->lwp_thread, p); 1404 userret(lp, frame, 0); 1405 #ifdef KTRACE 1406 if (KTRPOINT(lp->lwp_thread, KTR_SYSRET)) 1407 ktrsysret(lp, SYS_fork, 0, 0); 1408 #endif 1409 lp->lwp_flags |= LWP_PASSIVE_ACQ; 1410 userexit(lp); 1411 lp->lwp_flags &= ~LWP_PASSIVE_ACQ; 1412 } 1413 1414 /* 1415 * doreti has turned into this. The frame is directly on the stack. We 1416 * pull everything else we need (fpu and tls context) from the current 1417 * thread. 1418 * 1419 * Note on fpu interactions: In a virtual kernel, the fpu context for 1420 * an emulated user mode process is not shared with the virtual kernel's 1421 * fpu context, so we only have to 'stack' fpu contexts within the virtual 1422 * kernel itself, and not even then since the signal() contexts that we care 1423 * about save and restore the FPU state (I think anyhow). 1424 * 1425 * vmspace_ctl() returns an error only if it had problems instaling the 1426 * context we supplied or problems copying data to/from our VM space. 1427 */ 1428 void 1429 go_user(struct intrframe *frame) 1430 { 1431 struct trapframe *tf = (void *)&frame->if_rdi; 1432 int r; 1433 1434 /* 1435 * Interrupts may be disabled on entry, make sure all signals 1436 * can be received before beginning our loop. 1437 */ 1438 sigsetmask(0); 1439 1440 /* 1441 * Switch to the current simulated user process, then call 1442 * user_trap() when we break out of it (usually due to a signal). 1443 */ 1444 for (;;) { 1445 /* 1446 * Tell the real kernel whether it is ok to use the FP 1447 * unit or not. 1448 */ 1449 if (mdcpu->gd_npxthread == curthread) { 1450 tf->tf_xflags &= ~PGEX_FPFAULT; 1451 } else { 1452 tf->tf_xflags |= PGEX_FPFAULT; 1453 } 1454 1455 /* 1456 * Run emulated user process context. This call interlocks 1457 * with new mailbox signals. 1458 * 1459 * Set PGEX_U unconditionally, indicating a user frame (the 1460 * bit is normally set only by T_PAGEFLT). 1461 */ 1462 r = vmspace_ctl(&curproc->p_vmspace->vm_pmap, VMSPACE_CTL_RUN, 1463 tf, &curthread->td_savevext); 1464 frame->if_xflags |= PGEX_U; 1465 #if 0 1466 kprintf("GO USER %d trap %ld EVA %08lx RIP %08lx RSP %08lx XFLAGS %02lx/%02lx\n", 1467 r, tf->tf_trapno, tf->tf_addr, tf->tf_rip, tf->tf_rsp, 1468 tf->tf_xflags, frame->if_xflags); 1469 #endif 1470 if (r < 0) { 1471 if (errno != EINTR) 1472 panic("vmspace_ctl failed error %d", errno); 1473 } else { 1474 if (tf->tf_trapno) { 1475 user_trap(tf); 1476 } 1477 } 1478 if (mycpu->gd_reqflags & RQF_AST_MASK) { 1479 tf->tf_trapno = T_ASTFLT; 1480 user_trap(tf); 1481 } 1482 tf->tf_trapno = 0; 1483 } 1484 } 1485 1486 /* 1487 * If PGEX_FPFAULT is set then set FP_VIRTFP in the PCB to force a T_DNA 1488 * fault (which is then passed back to the virtual kernel) if an attempt is 1489 * made to use the FP unit. 1490 * 1491 * XXX this is a fairly big hack. 1492 */ 1493 void 1494 set_vkernel_fp(struct trapframe *frame) 1495 { 1496 struct thread *td = curthread; 1497 1498 if (frame->tf_xflags & PGEX_FPFAULT) { 1499 td->td_pcb->pcb_flags |= FP_VIRTFP; 1500 if (mdcpu->gd_npxthread == td) 1501 npxexit(); 1502 } else { 1503 td->td_pcb->pcb_flags &= ~FP_VIRTFP; 1504 } 1505 } 1506 1507 /* 1508 * Called from vkernel_trap() to fixup the vkernel's syscall 1509 * frame for vmspace_ctl() return. 1510 */ 1511 void 1512 cpu_vkernel_trap(struct trapframe *frame, int error) 1513 { 1514 frame->tf_rax = error; 1515 if (error) 1516 frame->tf_rflags |= PSL_C; 1517 else 1518 frame->tf_rflags &= ~PSL_C; 1519 } 1520