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/vkernel.h> 69 #include <sys/sysproto.h> 70 #include <sys/sysunion.h> 71 #include <sys/vmspace.h> 72 73 #include <vm/vm.h> 74 #include <vm/vm_param.h> 75 #include <sys/lock.h> 76 #include <vm/pmap.h> 77 #include <vm/vm_kern.h> 78 #include <vm/vm_map.h> 79 #include <vm/vm_page.h> 80 #include <vm/vm_extern.h> 81 82 #include <machine/cpu.h> 83 #include <machine/md_var.h> 84 #include <machine/pcb.h> 85 #include <machine/smp.h> 86 #include <machine/tss.h> 87 #include <machine/globaldata.h> 88 89 #include <ddb/ddb.h> 90 91 #include <sys/msgport2.h> 92 #include <sys/thread2.h> 93 #include <sys/mplock2.h> 94 95 #define MAKEMPSAFE(have_mplock) \ 96 if (have_mplock == 0) { \ 97 get_mplock(); \ 98 have_mplock = 1; \ 99 } 100 101 int (*pmath_emulate) (struct trapframe *); 102 103 extern int trapwrite (unsigned addr); 104 105 static int trap_pfault (struct trapframe *, int, vm_offset_t); 106 static void trap_fatal (struct trapframe *, int, vm_offset_t); 107 void dblfault_handler (void); 108 extern int vmm_enabled; 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 /* 165 * Passively intercepts the thread switch function to increase 166 * the thread priority from a user priority to a kernel priority, reducing 167 * syscall and trap overhead for the case where no switch occurs. 168 * 169 * Synchronizes td_ucred with p_ucred. This is used by system calls, 170 * signal handling, faults, AST traps, and anything else that enters the 171 * kernel from userland and provides the kernel with a stable read-only 172 * copy of the process ucred. 173 */ 174 static __inline void 175 userenter(struct thread *curtd, struct proc *curp) 176 { 177 struct ucred *ocred; 178 struct ucred *ncred; 179 180 curtd->td_release = lwkt_passive_release; 181 182 if (curtd->td_ucred != curp->p_ucred) { 183 ncred = crhold(curp->p_ucred); 184 ocred = curtd->td_ucred; 185 curtd->td_ucred = ncred; 186 if (ocred) 187 crfree(ocred); 188 } 189 } 190 191 /* 192 * Handle signals, profiling, and other AST's and/or tasks that 193 * must be completed before we can return to or try to return to userland. 194 * 195 * Note that td_sticks is a 64 bit quantity, but there's no point doing 64 196 * arithmatic on the delta calculation so the absolute tick values are 197 * truncated to an integer. 198 */ 199 static void 200 userret(struct lwp *lp, struct trapframe *frame, int sticks) 201 { 202 struct proc *p = lp->lwp_proc; 203 int sig; 204 205 /* 206 * Charge system time if profiling. Note: times are in microseconds. 207 * This may do a copyout and block, so do it first even though it 208 * means some system time will be charged as user time. 209 */ 210 if (p->p_flags & P_PROFIL) { 211 addupc_task(p, frame->tf_rip, 212 (u_int)((int)lp->lwp_thread->td_sticks - sticks)); 213 } 214 215 recheck: 216 /* 217 * Specific on-return-to-usermode checks (LWP_MP_WEXIT, 218 * LWP_MP_VNLRU, etc). 219 */ 220 if (lp->lwp_mpflags & LWP_MP_URETMASK) 221 lwpuserret(lp); 222 223 /* 224 * Block here if we are in a stopped state. 225 */ 226 if (p->p_stat == SSTOP) { 227 lwkt_gettoken(&p->p_token); 228 tstop(); 229 lwkt_reltoken(&p->p_token); 230 goto recheck; 231 } 232 233 /* 234 * Post any pending upcalls. If running a virtual kernel be sure 235 * to restore the virtual kernel's vmspace before posting the upcall. 236 */ 237 if (p->p_flags & (P_SIGVTALRM | P_SIGPROF)) { 238 lwkt_gettoken(&p->p_token); 239 if (p->p_flags & P_SIGVTALRM) { 240 p->p_flags &= ~P_SIGVTALRM; 241 ksignal(p, SIGVTALRM); 242 } 243 if (p->p_flags & P_SIGPROF) { 244 p->p_flags &= ~P_SIGPROF; 245 ksignal(p, SIGPROF); 246 } 247 lwkt_reltoken(&p->p_token); 248 goto recheck; 249 } 250 251 /* 252 * Post any pending signals 253 * 254 * WARNING! postsig() can exit and not return. 255 */ 256 if ((sig = CURSIG_TRACE(lp)) != 0) { 257 lwkt_gettoken(&p->p_token); 258 postsig(sig); 259 lwkt_reltoken(&p->p_token); 260 goto recheck; 261 } 262 263 /* 264 * block here if we are swapped out, but still process signals 265 * (such as SIGKILL). proc0 (the swapin scheduler) is already 266 * aware of our situation, we do not have to wake it up. 267 */ 268 if (p->p_flags & P_SWAPPEDOUT) { 269 lwkt_gettoken(&p->p_token); 270 get_mplock(); 271 p->p_flags |= P_SWAPWAIT; 272 swapin_request(); 273 if (p->p_flags & P_SWAPWAIT) 274 tsleep(p, PCATCH, "SWOUT", 0); 275 p->p_flags &= ~P_SWAPWAIT; 276 rel_mplock(); 277 lwkt_reltoken(&p->p_token); 278 goto recheck; 279 } 280 281 /* 282 * In a multi-threaded program it is possible for a thread to change 283 * signal state during a system call which temporarily changes the 284 * signal mask. In this case postsig() might not be run and we 285 * have to restore the mask ourselves. 286 */ 287 if (lp->lwp_flags & LWP_OLDMASK) { 288 lp->lwp_flags &= ~LWP_OLDMASK; 289 lp->lwp_sigmask = lp->lwp_oldsigmask; 290 goto recheck; 291 } 292 } 293 294 /* 295 * Cleanup from userenter and any passive release that might have occured. 296 * We must reclaim the current-process designation before we can return 297 * to usermode. We also handle both LWKT and USER reschedule requests. 298 */ 299 static __inline void 300 userexit(struct lwp *lp) 301 { 302 struct thread *td = lp->lwp_thread; 303 /* globaldata_t gd = td->td_gd; */ 304 305 /* 306 * Handle stop requests at kernel priority. Any requests queued 307 * after this loop will generate another AST. 308 */ 309 while (lp->lwp_proc->p_stat == SSTOP) { 310 lwkt_gettoken(&lp->lwp_proc->p_token); 311 tstop(); 312 lwkt_reltoken(&lp->lwp_proc->p_token); 313 } 314 315 /* 316 * Reduce our priority in preparation for a return to userland. If 317 * our passive release function was still in place, our priority was 318 * never raised and does not need to be reduced. 319 */ 320 lwkt_passive_recover(td); 321 322 /* 323 * Become the current user scheduled process if we aren't already, 324 * and deal with reschedule requests and other factors. 325 */ 326 lp->lwp_proc->p_usched->acquire_curproc(lp); 327 /* WARNING: we may have migrated cpu's */ 328 /* gd = td->td_gd; */ 329 } 330 331 #if !defined(KTR_KERNENTRY) 332 #define KTR_KERNENTRY KTR_ALL 333 #endif 334 KTR_INFO_MASTER(kernentry); 335 KTR_INFO(KTR_KERNENTRY, kernentry, trap, 0, 336 "TRAP(pid %hd, tid %hd, trapno %ld, eva %lu)", 337 pid_t pid, lwpid_t tid, register_t trapno, vm_offset_t eva); 338 KTR_INFO(KTR_KERNENTRY, kernentry, trap_ret, 0, "TRAP_RET(pid %hd, tid %hd)", 339 pid_t pid, lwpid_t tid); 340 KTR_INFO(KTR_KERNENTRY, kernentry, syscall, 0, "SYSC(pid %hd, tid %hd, nr %ld)", 341 pid_t pid, lwpid_t tid, register_t trapno); 342 KTR_INFO(KTR_KERNENTRY, kernentry, syscall_ret, 0, "SYSRET(pid %hd, tid %hd, err %d)", 343 pid_t pid, lwpid_t tid, int err); 344 KTR_INFO(KTR_KERNENTRY, kernentry, fork_ret, 0, "FORKRET(pid %hd, tid %hd)", 345 pid_t pid, lwpid_t tid); 346 347 /* 348 * Exception, fault, and trap interface to the kernel. 349 * This common code is called from assembly language IDT gate entry 350 * routines that prepare a suitable stack frame, and restore this 351 * frame after the exception has been processed. 352 * 353 * This function is also called from doreti in an interlock to handle ASTs. 354 * For example: hardwareint->INTROUTINE->(set ast)->doreti->trap 355 * 356 * NOTE! We have to retrieve the fault address prior to obtaining the 357 * MP lock because get_mplock() may switch out. YYY cr2 really ought 358 * to be retrieved by the assembly code, not here. 359 * 360 * XXX gd_trap_nesting_level currently prevents lwkt_switch() from panicing 361 * if an attempt is made to switch from a fast interrupt or IPI. This is 362 * necessary to properly take fatal kernel traps on SMP machines if 363 * get_mplock() has to block. 364 */ 365 366 void 367 user_trap(struct trapframe *frame) 368 { 369 struct globaldata *gd = mycpu; 370 struct thread *td = gd->gd_curthread; 371 struct lwp *lp = td->td_lwp; 372 struct proc *p; 373 int sticks = 0; 374 int i = 0, ucode = 0, type, code; 375 int have_mplock = 0; 376 #ifdef INVARIANTS 377 int crit_count = td->td_critcount; 378 lwkt_tokref_t curstop = td->td_toks_stop; 379 #endif 380 vm_offset_t eva; 381 382 p = td->td_proc; 383 384 if (frame->tf_trapno == T_PAGEFLT) 385 eva = frame->tf_addr; 386 else 387 eva = 0; 388 #if 0 389 kprintf("USER_TRAP AT %08lx xflags %ld trapno %ld eva %08lx\n", 390 frame->tf_rip, frame->tf_xflags, frame->tf_trapno, eva); 391 #endif 392 393 /* 394 * Everything coming from user mode runs through user_trap, 395 * including system calls. 396 */ 397 if (frame->tf_trapno == T_FAST_SYSCALL) { 398 syscall2(frame); 399 return; 400 } 401 402 KTR_LOG(kernentry_trap, lp->lwp_proc->p_pid, lp->lwp_tid, 403 frame->tf_trapno, eva); 404 405 #ifdef DDB 406 if (db_active) { 407 eva = (frame->tf_trapno == T_PAGEFLT ? rcr2() : 0); 408 ++gd->gd_trap_nesting_level; 409 MAKEMPSAFE(have_mplock); 410 trap_fatal(frame, TRUE, eva); 411 --gd->gd_trap_nesting_level; 412 goto out2; 413 } 414 #endif 415 416 type = frame->tf_trapno; 417 code = frame->tf_err; 418 419 userenter(td, p); 420 421 sticks = (int)td->td_sticks; 422 lp->lwp_md.md_regs = frame; 423 424 switch (type) { 425 case T_PRIVINFLT: /* privileged instruction fault */ 426 i = SIGILL; 427 ucode = ILL_PRVOPC; 428 break; 429 430 case T_BPTFLT: /* bpt instruction fault */ 431 case T_TRCTRAP: /* trace trap */ 432 frame->tf_rflags &= ~PSL_T; 433 i = SIGTRAP; 434 ucode = (type == T_TRCTRAP ? TRAP_TRACE : TRAP_BRKPT); 435 break; 436 437 case T_ARITHTRAP: /* arithmetic trap */ 438 ucode = code; 439 i = SIGFPE; 440 break; 441 442 case T_ASTFLT: /* Allow process switch */ 443 mycpu->gd_cnt.v_soft++; 444 if (mycpu->gd_reqflags & RQF_AST_OWEUPC) { 445 atomic_clear_int(&mycpu->gd_reqflags, RQF_AST_OWEUPC); 446 addupc_task(p, p->p_prof.pr_addr, p->p_prof.pr_ticks); 447 } 448 goto out; 449 450 /* 451 * The following two traps can happen in 452 * vm86 mode, and, if so, we want to handle 453 * them specially. 454 */ 455 case T_PROTFLT: /* general protection fault */ 456 case T_STKFLT: /* stack fault */ 457 #if 0 458 if (frame->tf_eflags & PSL_VM) { 459 i = vm86_emulate((struct vm86frame *)frame); 460 if (i == 0) 461 goto out; 462 break; 463 } 464 #endif 465 /* FALL THROUGH */ 466 467 case T_SEGNPFLT: /* segment not present fault */ 468 case T_TSSFLT: /* invalid TSS fault */ 469 case T_DOUBLEFLT: /* double fault */ 470 default: 471 i = SIGBUS; 472 ucode = code + BUS_SEGM_FAULT ; 473 break; 474 475 case T_PAGEFLT: /* page fault */ 476 i = trap_pfault(frame, TRUE, eva); 477 if (i == -1 || i == 0) 478 goto out; 479 480 481 if (i == SIGSEGV) 482 ucode = SEGV_MAPERR; 483 else { 484 i = SIGSEGV; 485 ucode = SEGV_ACCERR; 486 } 487 break; 488 489 case T_DIVIDE: /* integer divide fault */ 490 ucode = FPE_INTDIV; 491 i = SIGFPE; 492 break; 493 494 #if NISA > 0 495 case T_NMI: 496 MAKEMPSAFE(have_mplock); 497 /* machine/parity/power fail/"kitchen sink" faults */ 498 if (isa_nmi(code) == 0) { 499 #ifdef DDB 500 /* 501 * NMI can be hooked up to a pushbutton 502 * for debugging. 503 */ 504 if (ddb_on_nmi) { 505 kprintf ("NMI ... going to debugger\n"); 506 kdb_trap(type, 0, frame); 507 } 508 #endif /* DDB */ 509 goto out2; 510 } else if (panic_on_nmi) 511 panic("NMI indicates hardware failure"); 512 break; 513 #endif /* NISA > 0 */ 514 515 case T_OFLOW: /* integer overflow fault */ 516 ucode = FPE_INTOVF; 517 i = SIGFPE; 518 break; 519 520 case T_BOUND: /* bounds check fault */ 521 ucode = FPE_FLTSUB; 522 i = SIGFPE; 523 break; 524 525 case T_DNA: 526 /* 527 * Virtual kernel intercept - pass the DNA exception 528 * to the (emulated) virtual kernel if it asked to handle 529 * it. This occurs when the virtual kernel is holding 530 * onto the FP context for a different emulated 531 * process then the one currently running. 532 * 533 * We must still call npxdna() since we may have 534 * saved FP state that the (emulated) virtual kernel 535 * needs to hand over to a different emulated process. 536 */ 537 if (lp->lwp_vkernel && lp->lwp_vkernel->ve && 538 (td->td_pcb->pcb_flags & FP_VIRTFP) 539 ) { 540 npxdna(frame); 541 break; 542 } 543 544 /* 545 * The kernel may have switched out the FP unit's 546 * state, causing the user process to take a fault 547 * when it tries to use the FP unit. Restore the 548 * state here 549 */ 550 if (npxdna(frame)) 551 goto out; 552 if (!pmath_emulate) { 553 i = SIGFPE; 554 ucode = FPE_FPU_NP_TRAP; 555 break; 556 } 557 i = (*pmath_emulate)(frame); 558 if (i == 0) { 559 if (!(frame->tf_rflags & PSL_T)) 560 goto out2; 561 frame->tf_rflags &= ~PSL_T; 562 i = SIGTRAP; 563 } 564 /* else ucode = emulator_only_knows() XXX */ 565 break; 566 567 case T_FPOPFLT: /* FPU operand fetch fault */ 568 ucode = T_FPOPFLT; 569 i = SIGILL; 570 break; 571 572 case T_XMMFLT: /* SIMD floating-point exception */ 573 ucode = 0; /* XXX */ 574 i = SIGFPE; 575 break; 576 } 577 578 /* 579 * Virtual kernel intercept - if the fault is directly related to a 580 * VM context managed by a virtual kernel then let the virtual kernel 581 * handle it. 582 */ 583 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) { 584 vkernel_trap(lp, frame); 585 goto out; 586 } 587 588 /* 589 * Translate fault for emulators (e.g. Linux) 590 */ 591 if (*p->p_sysent->sv_transtrap) 592 i = (*p->p_sysent->sv_transtrap)(i, type); 593 594 MAKEMPSAFE(have_mplock); 595 trapsignal(lp, i, ucode); 596 597 #ifdef DEBUG 598 if (type <= MAX_TRAP_MSG) { 599 uprintf("fatal process exception: %s", 600 trap_msg[type]); 601 if ((type == T_PAGEFLT) || (type == T_PROTFLT)) 602 uprintf(", fault VA = 0x%lx", (u_long)eva); 603 uprintf("\n"); 604 } 605 #endif 606 607 out: 608 userret(lp, frame, sticks); 609 userexit(lp); 610 out2: ; 611 if (have_mplock) 612 rel_mplock(); 613 KTR_LOG(kernentry_trap_ret, lp->lwp_proc->p_pid, lp->lwp_tid); 614 #ifdef INVARIANTS 615 KASSERT(crit_count == td->td_critcount, 616 ("trap: critical section count mismatch! %d/%d", 617 crit_count, td->td_pri)); 618 KASSERT(curstop == td->td_toks_stop, 619 ("trap: extra tokens held after trap! %ld/%ld", 620 curstop - &td->td_toks_base, 621 td->td_toks_stop - &td->td_toks_base)); 622 #endif 623 } 624 625 void 626 kern_trap(struct trapframe *frame) 627 { 628 struct globaldata *gd = mycpu; 629 struct thread *td = gd->gd_curthread; 630 struct lwp *lp; 631 struct proc *p; 632 int i = 0, ucode = 0, type, code; 633 int have_mplock = 0; 634 #ifdef INVARIANTS 635 int crit_count = td->td_critcount; 636 lwkt_tokref_t curstop = td->td_toks_stop; 637 #endif 638 vm_offset_t eva; 639 640 lp = td->td_lwp; 641 p = td->td_proc; 642 643 if (frame->tf_trapno == T_PAGEFLT) 644 eva = frame->tf_addr; 645 else 646 eva = 0; 647 648 #ifdef DDB 649 if (db_active) { 650 ++gd->gd_trap_nesting_level; 651 MAKEMPSAFE(have_mplock); 652 trap_fatal(frame, FALSE, eva); 653 --gd->gd_trap_nesting_level; 654 goto out2; 655 } 656 #endif 657 658 type = frame->tf_trapno; 659 code = frame->tf_err; 660 661 #if 0 662 kernel_trap: 663 #endif 664 /* kernel trap */ 665 666 switch (type) { 667 case T_PAGEFLT: /* page fault */ 668 trap_pfault(frame, FALSE, eva); 669 goto out2; 670 671 case T_DNA: 672 /* 673 * The kernel may be using npx for copying or other 674 * purposes. 675 */ 676 panic("kernel NPX should not happen"); 677 if (npxdna(frame)) 678 goto out2; 679 break; 680 681 case T_PROTFLT: /* general protection fault */ 682 case T_SEGNPFLT: /* segment not present fault */ 683 /* 684 * Invalid segment selectors and out of bounds 685 * %eip's and %esp's can be set up in user mode. 686 * This causes a fault in kernel mode when the 687 * kernel tries to return to user mode. We want 688 * to get this fault so that we can fix the 689 * problem here and not have to check all the 690 * selectors and pointers when the user changes 691 * them. 692 */ 693 if (mycpu->gd_intr_nesting_level == 0) { 694 if (td->td_pcb->pcb_onfault) { 695 frame->tf_rip = 696 (register_t)td->td_pcb->pcb_onfault; 697 goto out2; 698 } 699 } 700 break; 701 702 case T_TSSFLT: 703 /* 704 * PSL_NT can be set in user mode and isn't cleared 705 * automatically when the kernel is entered. This 706 * causes a TSS fault when the kernel attempts to 707 * `iret' because the TSS link is uninitialized. We 708 * want to get this fault so that we can fix the 709 * problem here and not every time the kernel is 710 * entered. 711 */ 712 if (frame->tf_rflags & PSL_NT) { 713 frame->tf_rflags &= ~PSL_NT; 714 goto out2; 715 } 716 break; 717 718 case T_TRCTRAP: /* trace trap */ 719 #if 0 720 if (frame->tf_eip == (int)IDTVEC(syscall)) { 721 /* 722 * We've just entered system mode via the 723 * syscall lcall. Continue single stepping 724 * silently until the syscall handler has 725 * saved the flags. 726 */ 727 goto out2; 728 } 729 if (frame->tf_eip == (int)IDTVEC(syscall) + 1) { 730 /* 731 * The syscall handler has now saved the 732 * flags. Stop single stepping it. 733 */ 734 frame->tf_eflags &= ~PSL_T; 735 goto out2; 736 } 737 #endif 738 #if 0 739 /* 740 * Ignore debug register trace traps due to 741 * accesses in the user's address space, which 742 * can happen under several conditions such as 743 * if a user sets a watchpoint on a buffer and 744 * then passes that buffer to a system call. 745 * We still want to get TRCTRAPS for addresses 746 * in kernel space because that is useful when 747 * debugging the kernel. 748 */ 749 if (user_dbreg_trap()) { 750 /* 751 * Reset breakpoint bits because the 752 * processor doesn't 753 */ 754 load_dr6(rdr6() & 0xfffffff0); 755 goto out2; 756 } 757 #endif 758 /* 759 * Fall through (TRCTRAP kernel mode, kernel address) 760 */ 761 case T_BPTFLT: 762 /* 763 * If DDB is enabled, let it handle the debugger trap. 764 * Otherwise, debugger traps "can't happen". 765 */ 766 #ifdef DDB 767 MAKEMPSAFE(have_mplock); 768 if (kdb_trap (type, 0, frame)) 769 goto out2; 770 #endif 771 break; 772 case T_DIVIDE: 773 MAKEMPSAFE(have_mplock); 774 trap_fatal(frame, FALSE, eva); 775 goto out2; 776 case T_NMI: 777 MAKEMPSAFE(have_mplock); 778 trap_fatal(frame, FALSE, eva); 779 goto out2; 780 case T_SYSCALL80: 781 case T_FAST_SYSCALL: 782 /* 783 * Ignore this trap generated from a spurious SIGTRAP. 784 * 785 * single stepping in / syscalls leads to spurious / SIGTRAP 786 * so ignore 787 * 788 * Haiku (c) 2007 Simon 'corecode' Schubert 789 */ 790 goto out2; 791 } 792 793 /* 794 * Translate fault for emulators (e.g. Linux) 795 */ 796 if (*p->p_sysent->sv_transtrap) 797 i = (*p->p_sysent->sv_transtrap)(i, type); 798 799 MAKEMPSAFE(have_mplock); 800 trapsignal(lp, i, ucode); 801 802 #ifdef DEBUG 803 if (type <= MAX_TRAP_MSG) { 804 uprintf("fatal process exception: %s", 805 trap_msg[type]); 806 if ((type == T_PAGEFLT) || (type == T_PROTFLT)) 807 uprintf(", fault VA = 0x%lx", (u_long)eva); 808 uprintf("\n"); 809 } 810 #endif 811 812 out2: 813 ; 814 if (have_mplock) 815 rel_mplock(); 816 #ifdef INVARIANTS 817 KASSERT(crit_count == td->td_critcount, 818 ("trap: critical section count mismatch! %d/%d", 819 crit_count, td->td_pri)); 820 KASSERT(curstop == td->td_toks_stop, 821 ("trap: extra tokens held after trap! %ld/%ld", 822 curstop - &td->td_toks_base, 823 td->td_toks_stop - &td->td_toks_base)); 824 #endif 825 } 826 827 int 828 trap_pfault(struct trapframe *frame, int usermode, vm_offset_t eva) 829 { 830 vm_offset_t va; 831 struct vmspace *vm = NULL; 832 vm_map_t map = 0; 833 int rv = 0; 834 vm_prot_t ftype; 835 thread_t td = curthread; 836 struct lwp *lp = td->td_lwp; 837 int fault_flags; 838 839 va = trunc_page(eva); 840 if (usermode == FALSE) { 841 /* 842 * This is a fault on kernel virtual memory. 843 */ 844 map = &kernel_map; 845 } else { 846 /* 847 * This is a fault on non-kernel virtual memory. 848 * vm is initialized above to NULL. If curproc is NULL 849 * or curproc->p_vmspace is NULL the fault is fatal. 850 */ 851 if (lp != NULL) 852 vm = lp->lwp_vmspace; 853 854 if (vm == NULL) 855 goto nogo; 856 857 map = &vm->vm_map; 858 } 859 860 if (frame->tf_err & PGEX_W) 861 ftype = VM_PROT_READ | VM_PROT_WRITE; 862 else 863 ftype = VM_PROT_READ; 864 865 if (map != &kernel_map) { 866 /* 867 * Keep swapout from messing with us during this 868 * critical time. 869 */ 870 PHOLD(lp->lwp_proc); 871 872 /* 873 * Grow the stack if necessary 874 */ 875 /* grow_stack returns false only if va falls into 876 * a growable stack region and the stack growth 877 * fails. It returns true if va was not within 878 * a growable stack region, or if the stack 879 * growth succeeded. 880 */ 881 if (!grow_stack (lp->lwp_proc, va)) { 882 rv = KERN_FAILURE; 883 PRELE(lp->lwp_proc); 884 goto nogo; 885 } 886 887 fault_flags = 0; 888 if (usermode) 889 fault_flags |= VM_FAULT_BURST; 890 if (ftype & VM_PROT_WRITE) 891 fault_flags |= VM_FAULT_DIRTY; 892 else 893 fault_flags |= VM_FAULT_NORMAL; 894 rv = vm_fault(map, va, ftype, fault_flags); 895 896 PRELE(lp->lwp_proc); 897 } else { 898 /* 899 * Don't have to worry about process locking or stacks in the kernel. 900 */ 901 rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL); 902 } 903 904 if (rv == KERN_SUCCESS) 905 return (0); 906 nogo: 907 if (!usermode) { 908 if (td->td_gd->gd_intr_nesting_level == 0 && 909 td->td_pcb->pcb_onfault) { 910 frame->tf_rip = (register_t)td->td_pcb->pcb_onfault; 911 return (0); 912 } 913 trap_fatal(frame, usermode, eva); 914 return (-1); 915 } 916 917 /* 918 * NOTE: on x86_64 we have a tf_addr field in the trapframe, no 919 * kludge is needed to pass the fault address to signal handlers. 920 */ 921 struct proc *p = td->td_proc; 922 kprintf("seg-fault accessing address %p rip=%p pid=%d p_comm=%s\n", 923 (void *)va, (void *)frame->tf_rip, p->p_pid, p->p_comm); 924 /* Debugger("seg-fault"); */ 925 926 return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV); 927 } 928 929 static void 930 trap_fatal(struct trapframe *frame, int usermode, vm_offset_t eva) 931 { 932 int code, type, ss; 933 long rsp; 934 935 code = frame->tf_xflags; 936 type = frame->tf_trapno; 937 938 if (type <= MAX_TRAP_MSG) { 939 kprintf("\n\nFatal trap %d: %s while in %s mode\n", 940 type, trap_msg[type], 941 (usermode ? "user" : "kernel")); 942 } 943 /* two separate prints in case of a trap on an unmapped page */ 944 kprintf("cpuid = %d\n", mycpu->gd_cpuid); 945 if (type == T_PAGEFLT) { 946 kprintf("fault virtual address = %p\n", (void *)eva); 947 kprintf("fault code = %s %s, %s\n", 948 usermode ? "user" : "supervisor", 949 code & PGEX_W ? "write" : "read", 950 code & PGEX_P ? "protection violation" : "page not present"); 951 } 952 kprintf("instruction pointer = 0x%lx:0x%lx\n", 953 frame->tf_cs & 0xffff, frame->tf_rip); 954 if (usermode) { 955 ss = frame->tf_ss & 0xffff; 956 rsp = frame->tf_rsp; 957 } else { 958 ss = GSEL(GDATA_SEL, SEL_KPL); 959 rsp = (long)&frame->tf_rsp; 960 } 961 kprintf("stack pointer = 0x%x:0x%lx\n", ss, rsp); 962 kprintf("frame pointer = 0x%x:0x%lx\n", ss, frame->tf_rbp); 963 kprintf("processor eflags = "); 964 if (frame->tf_rflags & PSL_T) 965 kprintf("trace trap, "); 966 if (frame->tf_rflags & PSL_I) 967 kprintf("interrupt enabled, "); 968 if (frame->tf_rflags & PSL_NT) 969 kprintf("nested task, "); 970 if (frame->tf_rflags & PSL_RF) 971 kprintf("resume, "); 972 #if 0 973 if (frame->tf_eflags & PSL_VM) 974 kprintf("vm86, "); 975 #endif 976 kprintf("IOPL = %jd\n", (intmax_t)((frame->tf_rflags & PSL_IOPL) >> 12)); 977 kprintf("current process = "); 978 if (curproc) { 979 kprintf("%lu (%s)\n", 980 (u_long)curproc->p_pid, curproc->p_comm ? 981 curproc->p_comm : ""); 982 } else { 983 kprintf("Idle\n"); 984 } 985 kprintf("current thread = pri %d ", curthread->td_pri); 986 if (curthread->td_critcount) 987 kprintf("(CRIT)"); 988 kprintf("\n"); 989 /** 990 * XXX FIXME: 991 * we probably SHOULD have stopped the other CPUs before now! 992 * another CPU COULD have been touching cpl at this moment... 993 */ 994 kprintf(" <- SMP: XXX"); 995 kprintf("\n"); 996 997 #ifdef KDB 998 if (kdb_trap(&psl)) 999 return; 1000 #endif 1001 #ifdef DDB 1002 if ((debugger_on_panic || db_active) && kdb_trap(type, code, frame)) 1003 return; 1004 #endif 1005 kprintf("trap number = %d\n", type); 1006 if (type <= MAX_TRAP_MSG) 1007 panic("%s", trap_msg[type]); 1008 else 1009 panic("unknown/reserved trap"); 1010 } 1011 1012 /* 1013 * Double fault handler. Called when a fault occurs while writing 1014 * a frame for a trap/exception onto the stack. This usually occurs 1015 * when the stack overflows (such is the case with infinite recursion, 1016 * for example). 1017 * 1018 * XXX Note that the current PTD gets replaced by IdlePTD when the 1019 * task switch occurs. This means that the stack that was active at 1020 * the time of the double fault is not available at <kstack> unless 1021 * the machine was idle when the double fault occurred. The downside 1022 * of this is that "trace <ebp>" in ddb won't work. 1023 */ 1024 void 1025 dblfault_handler(void) 1026 { 1027 #if JG 1028 struct mdglobaldata *gd = mdcpu; 1029 #endif 1030 1031 kprintf("\nFatal double fault:\n"); 1032 #if JG 1033 kprintf("rip = 0x%lx\n", gd->gd_common_tss.tss_rip); 1034 kprintf("rsp = 0x%lx\n", gd->gd_common_tss.tss_rsp); 1035 kprintf("rbp = 0x%lx\n", gd->gd_common_tss.tss_rbp); 1036 #endif 1037 /* two separate prints in case of a trap on an unmapped page */ 1038 kprintf("cpuid = %d\n", mycpu->gd_cpuid); 1039 panic("double fault"); 1040 } 1041 1042 /* 1043 * Compensate for 386 brain damage (missing URKR). 1044 * This is a little simpler than the pagefault handler in trap() because 1045 * it the page tables have already been faulted in and high addresses 1046 * are thrown out early for other reasons. 1047 */ 1048 int 1049 trapwrite(unsigned addr) 1050 { 1051 struct lwp *lp; 1052 vm_offset_t va; 1053 struct vmspace *vm; 1054 int rv; 1055 1056 va = trunc_page((vm_offset_t)addr); 1057 /* 1058 * XXX - MAX is END. Changed > to >= for temp. fix. 1059 */ 1060 if (va >= VM_MAX_USER_ADDRESS) 1061 return (1); 1062 1063 lp = curthread->td_lwp; 1064 vm = lp->lwp_vmspace; 1065 1066 PHOLD(lp->lwp_proc); 1067 1068 if (!grow_stack (lp->lwp_proc, va)) { 1069 PRELE(lp->lwp_proc); 1070 return (1); 1071 } 1072 1073 /* 1074 * fault the data page 1075 */ 1076 rv = vm_fault(&vm->vm_map, va, VM_PROT_WRITE, VM_FAULT_DIRTY); 1077 1078 PRELE(lp->lwp_proc); 1079 1080 if (rv != KERN_SUCCESS) 1081 return 1; 1082 1083 return (0); 1084 } 1085 1086 /* 1087 * syscall2 - MP aware system call request C handler 1088 * 1089 * A system call is essentially treated as a trap except that the 1090 * MP lock is not held on entry or return. We are responsible for 1091 * obtaining the MP lock if necessary and for handling ASTs 1092 * (e.g. a task switch) prior to return. 1093 * 1094 * In general, only simple access and manipulation of curproc and 1095 * the current stack is allowed without having to hold MP lock. 1096 * 1097 * MPSAFE - note that large sections of this routine are run without 1098 * the MP lock. 1099 */ 1100 void 1101 syscall2(struct trapframe *frame) 1102 { 1103 struct thread *td = curthread; 1104 struct proc *p = td->td_proc; 1105 struct lwp *lp = td->td_lwp; 1106 caddr_t params; 1107 struct sysent *callp; 1108 register_t orig_tf_rflags; 1109 int sticks; 1110 int error; 1111 int narg; 1112 #ifdef INVARIANTS 1113 int crit_count = td->td_critcount; 1114 lwkt_tokref_t curstop = td->td_toks_stop; 1115 #endif 1116 int have_mplock = 0; 1117 register_t *argp; 1118 u_int code; 1119 int reg, regcnt; 1120 union sysunion args; 1121 register_t *argsdst; 1122 1123 mycpu->gd_cnt.v_syscall++; 1124 1125 KTR_LOG(kernentry_syscall, lp->lwp_proc->p_pid, lp->lwp_tid, 1126 frame->tf_rax); 1127 1128 userenter(td, p); /* lazy raise our priority */ 1129 1130 reg = 0; 1131 regcnt = 6; 1132 /* 1133 * Misc 1134 */ 1135 sticks = (int)td->td_sticks; 1136 orig_tf_rflags = frame->tf_rflags; 1137 1138 /* 1139 * Virtual kernel intercept - if a VM context managed by a virtual 1140 * kernel issues a system call the virtual kernel handles it, not us. 1141 * Restore the virtual kernel context and return from its system 1142 * call. The current frame is copied out to the virtual kernel. 1143 */ 1144 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) { 1145 vkernel_trap(lp, frame); 1146 error = EJUSTRETURN; 1147 goto out; 1148 } 1149 1150 /* 1151 * Get the system call parameters and account for time 1152 */ 1153 lp->lwp_md.md_regs = frame; 1154 params = (caddr_t)frame->tf_rsp + sizeof(register_t); 1155 code = frame->tf_rax; 1156 1157 if (p->p_sysent->sv_prepsyscall) { 1158 (*p->p_sysent->sv_prepsyscall)( 1159 frame, (int *)(&args.nosys.sysmsg + 1), 1160 &code, ¶ms); 1161 } else { 1162 if (code == SYS_syscall || code == SYS___syscall) { 1163 code = frame->tf_rdi; 1164 reg++; 1165 regcnt--; 1166 } 1167 } 1168 1169 if (p->p_sysent->sv_mask) 1170 code &= p->p_sysent->sv_mask; 1171 1172 if (code >= p->p_sysent->sv_size) 1173 callp = &p->p_sysent->sv_table[0]; 1174 else 1175 callp = &p->p_sysent->sv_table[code]; 1176 1177 narg = callp->sy_narg & SYF_ARGMASK; 1178 1179 /* 1180 * On x86_64 we get up to six arguments in registers. The rest are 1181 * on the stack. The first six members of 'struct trapframe' happen 1182 * to be the registers used to pass arguments, in exactly the right 1183 * order. 1184 */ 1185 argp = &frame->tf_rdi; 1186 argp += reg; 1187 argsdst = (register_t *)(&args.nosys.sysmsg + 1); 1188 /* 1189 * JG can we overflow the space pointed to by 'argsdst' 1190 * either with 'bcopy' or with 'copyin'? 1191 */ 1192 bcopy(argp, argsdst, sizeof(register_t) * regcnt); 1193 /* 1194 * copyin is MP aware, but the tracing code is not 1195 */ 1196 if (narg > regcnt) { 1197 KASSERT(params != NULL, ("copyin args with no params!")); 1198 error = copyin(params, &argsdst[regcnt], 1199 (narg - regcnt) * sizeof(register_t)); 1200 if (error) { 1201 #ifdef KTRACE 1202 if (KTRPOINT(td, KTR_SYSCALL)) { 1203 MAKEMPSAFE(have_mplock); 1204 1205 ktrsyscall(lp, code, narg, 1206 (void *)(&args.nosys.sysmsg + 1)); 1207 } 1208 #endif 1209 goto bad; 1210 } 1211 } 1212 1213 #ifdef KTRACE 1214 if (KTRPOINT(td, KTR_SYSCALL)) { 1215 MAKEMPSAFE(have_mplock); 1216 ktrsyscall(lp, code, narg, (void *)(&args.nosys.sysmsg + 1)); 1217 } 1218 #endif 1219 1220 /* 1221 * Default return value is 0 (will be copied to %rax). Double-value 1222 * returns use %rax and %rdx. %rdx is left unchanged for system 1223 * calls which return only one result. 1224 */ 1225 args.sysmsg_fds[0] = 0; 1226 args.sysmsg_fds[1] = frame->tf_rdx; 1227 1228 /* 1229 * The syscall might manipulate the trap frame. If it does it 1230 * will probably return EJUSTRETURN. 1231 */ 1232 args.sysmsg_frame = frame; 1233 1234 STOPEVENT(p, S_SCE, narg); /* MP aware */ 1235 1236 /* 1237 * NOTE: All system calls run MPSAFE now. The system call itself 1238 * is responsible for getting the MP lock. 1239 */ 1240 error = (*callp->sy_call)(&args); 1241 1242 #if 0 1243 kprintf("system call %d returned %d\n", code, error); 1244 #endif 1245 1246 out: 1247 /* 1248 * MP SAFE (we may or may not have the MP lock at this point) 1249 */ 1250 switch (error) { 1251 case 0: 1252 /* 1253 * Reinitialize proc pointer `p' as it may be different 1254 * if this is a child returning from fork syscall. 1255 */ 1256 p = curproc; 1257 lp = curthread->td_lwp; 1258 frame->tf_rax = args.sysmsg_fds[0]; 1259 frame->tf_rdx = args.sysmsg_fds[1]; 1260 frame->tf_rflags &= ~PSL_C; 1261 break; 1262 case ERESTART: 1263 /* 1264 * Reconstruct pc, we know that 'syscall' is 2 bytes. 1265 * We have to do a full context restore so that %r10 1266 * (which was holding the value of %rcx) is restored for 1267 * the next iteration. 1268 */ 1269 frame->tf_rip -= frame->tf_err; 1270 frame->tf_r10 = frame->tf_rcx; 1271 break; 1272 case EJUSTRETURN: 1273 break; 1274 case EASYNC: 1275 panic("Unexpected EASYNC return value (for now)"); 1276 default: 1277 bad: 1278 if (p->p_sysent->sv_errsize) { 1279 if (error >= p->p_sysent->sv_errsize) 1280 error = -1; /* XXX */ 1281 else 1282 error = p->p_sysent->sv_errtbl[error]; 1283 } 1284 frame->tf_rax = error; 1285 frame->tf_rflags |= PSL_C; 1286 break; 1287 } 1288 1289 /* 1290 * Traced syscall. trapsignal() is not MP aware. 1291 */ 1292 if (orig_tf_rflags & PSL_T) { 1293 MAKEMPSAFE(have_mplock); 1294 frame->tf_rflags &= ~PSL_T; 1295 trapsignal(lp, SIGTRAP, 0); 1296 } 1297 1298 /* 1299 * Handle reschedule and other end-of-syscall issues 1300 */ 1301 userret(lp, frame, sticks); 1302 1303 #ifdef KTRACE 1304 if (KTRPOINT(td, KTR_SYSRET)) { 1305 MAKEMPSAFE(have_mplock); 1306 ktrsysret(lp, code, error, args.sysmsg_result); 1307 } 1308 #endif 1309 1310 /* 1311 * This works because errno is findable through the 1312 * register set. If we ever support an emulation where this 1313 * is not the case, this code will need to be revisited. 1314 */ 1315 STOPEVENT(p, S_SCX, code); 1316 1317 userexit(lp); 1318 /* 1319 * Release the MP lock if we had to get it 1320 */ 1321 if (have_mplock) 1322 rel_mplock(); 1323 KTR_LOG(kernentry_syscall_ret, lp->lwp_proc->p_pid, lp->lwp_tid, error); 1324 #ifdef INVARIANTS 1325 KASSERT(&td->td_toks_base == td->td_toks_stop, 1326 ("syscall: critical section count mismatch! %d/%d", 1327 crit_count, td->td_pri)); 1328 KASSERT(curstop == td->td_toks_stop, 1329 ("syscall: extra tokens held after trap! %ld", 1330 td->td_toks_stop - &td->td_toks_base)); 1331 #endif 1332 } 1333 1334 /* 1335 * NOTE: mplock not held at any point 1336 */ 1337 void 1338 fork_return(struct lwp *lp, struct trapframe *frame) 1339 { 1340 frame->tf_rax = 0; /* Child returns zero */ 1341 frame->tf_rflags &= ~PSL_C; /* success */ 1342 frame->tf_rdx = 1; 1343 1344 generic_lwp_return(lp, frame); 1345 KTR_LOG(kernentry_fork_ret, lp->lwp_proc->p_pid, lp->lwp_tid); 1346 } 1347 1348 /* 1349 * Simplified back end of syscall(), used when returning from fork() 1350 * directly into user mode. 1351 * 1352 * This code will return back into the fork trampoline code which then 1353 * runs doreti. 1354 * 1355 * NOTE: The mplock is not held at any point. 1356 */ 1357 void 1358 generic_lwp_return(struct lwp *lp, struct trapframe *frame) 1359 { 1360 struct proc *p = lp->lwp_proc; 1361 1362 /* 1363 * Newly forked processes are given a kernel priority. We have to 1364 * adjust the priority to a normal user priority and fake entry 1365 * into the kernel (call userenter()) to install a passive release 1366 * function just in case userret() decides to stop the process. This 1367 * can occur when ^Z races a fork. If we do not install the passive 1368 * release function the current process designation will not be 1369 * released when the thread goes to sleep. 1370 */ 1371 lwkt_setpri_self(TDPRI_USER_NORM); 1372 userenter(lp->lwp_thread, p); 1373 userret(lp, frame, 0); 1374 #ifdef KTRACE 1375 if (KTRPOINT(lp->lwp_thread, KTR_SYSRET)) 1376 ktrsysret(lp, SYS_fork, 0, 0); 1377 #endif 1378 lp->lwp_flags |= LWP_PASSIVE_ACQ; 1379 userexit(lp); 1380 lp->lwp_flags &= ~LWP_PASSIVE_ACQ; 1381 } 1382 1383 /* 1384 * doreti has turned into this. The frame is directly on the stack. We 1385 * pull everything else we need (fpu and tls context) from the current 1386 * thread. 1387 * 1388 * Note on fpu interactions: In a virtual kernel, the fpu context for 1389 * an emulated user mode process is not shared with the virtual kernel's 1390 * fpu context, so we only have to 'stack' fpu contexts within the virtual 1391 * kernel itself, and not even then since the signal() contexts that we care 1392 * about save and restore the FPU state (I think anyhow). 1393 * 1394 * vmspace_ctl() returns an error only if it had problems instaling the 1395 * context we supplied or problems copying data to/from our VM space. 1396 */ 1397 void 1398 go_user(struct intrframe *frame) 1399 { 1400 struct trapframe *tf = (void *)&frame->if_rdi; 1401 int r; 1402 void *id; 1403 1404 /* 1405 * Interrupts may be disabled on entry, make sure all signals 1406 * can be received before beginning our loop. 1407 */ 1408 sigsetmask(0); 1409 1410 /* 1411 * Switch to the current simulated user process, then call 1412 * user_trap() when we break out of it (usually due to a signal). 1413 */ 1414 for (;;) { 1415 /* 1416 * Tell the real kernel whether it is ok to use the FP 1417 * unit or not. 1418 */ 1419 if (mdcpu->gd_npxthread == curthread) { 1420 tf->tf_xflags &= ~PGEX_FPFAULT; 1421 } else { 1422 tf->tf_xflags |= PGEX_FPFAULT; 1423 } 1424 1425 /* 1426 * Run emulated user process context. This call interlocks 1427 * with new mailbox signals. 1428 * 1429 * Set PGEX_U unconditionally, indicating a user frame (the 1430 * bit is normally set only by T_PAGEFLT). 1431 */ 1432 if (vmm_enabled) 1433 id = (void *)vtophys(curproc->p_vmspace->vm_pmap.pm_pml4); 1434 else 1435 id = &curproc->p_vmspace->vm_pmap; 1436 1437 r = vmspace_ctl(id, VMSPACE_CTL_RUN, tf, &curthread->td_savevext); 1438 1439 frame->if_xflags |= PGEX_U; 1440 #if 0 1441 kprintf("GO USER %d trap %ld EVA %08lx RIP %08lx RSP %08lx XFLAGS %02lx/%02lx\n", 1442 r, tf->tf_trapno, tf->tf_addr, tf->tf_rip, tf->tf_rsp, 1443 tf->tf_xflags, frame->if_xflags); 1444 #endif 1445 if (r < 0) { 1446 if (errno != EINTR) 1447 panic("vmspace_ctl failed error %d", errno); 1448 } else { 1449 if (tf->tf_trapno) { 1450 user_trap(tf); 1451 } 1452 } 1453 if (mycpu->gd_reqflags & RQF_AST_MASK) { 1454 tf->tf_trapno = T_ASTFLT; 1455 user_trap(tf); 1456 } 1457 tf->tf_trapno = 0; 1458 } 1459 } 1460 1461 /* 1462 * If PGEX_FPFAULT is set then set FP_VIRTFP in the PCB to force a T_DNA 1463 * fault (which is then passed back to the virtual kernel) if an attempt is 1464 * made to use the FP unit. 1465 * 1466 * XXX this is a fairly big hack. 1467 */ 1468 void 1469 set_vkernel_fp(struct trapframe *frame) 1470 { 1471 struct thread *td = curthread; 1472 1473 if (frame->tf_xflags & PGEX_FPFAULT) { 1474 td->td_pcb->pcb_flags |= FP_VIRTFP; 1475 if (mdcpu->gd_npxthread == td) 1476 npxexit(); 1477 } else { 1478 td->td_pcb->pcb_flags &= ~FP_VIRTFP; 1479 } 1480 } 1481 1482 /* 1483 * Called from vkernel_trap() to fixup the vkernel's syscall 1484 * frame for vmspace_ctl() return. 1485 */ 1486 void 1487 cpu_vkernel_trap(struct trapframe *frame, int error) 1488 { 1489 frame->tf_rax = error; 1490 if (error) 1491 frame->tf_rflags |= PSL_C; 1492 else 1493 frame->tf_rflags &= ~PSL_C; 1494 } 1495