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); 108 109 #if 0 110 extern inthand_t IDTVEC(syscall); 111 #endif 112 113 #define MAX_TRAP_MSG 30 114 static char *trap_msg[] = { 115 "", /* 0 unused */ 116 "privileged instruction fault", /* 1 T_PRIVINFLT */ 117 "", /* 2 unused */ 118 "breakpoint instruction fault", /* 3 T_BPTFLT */ 119 "", /* 4 unused */ 120 "", /* 5 unused */ 121 "arithmetic trap", /* 6 T_ARITHTRAP */ 122 "system forced exception", /* 7 T_ASTFLT */ 123 "", /* 8 unused */ 124 "general protection fault", /* 9 T_PROTFLT */ 125 "trace trap", /* 10 T_TRCTRAP */ 126 "", /* 11 unused */ 127 "page fault", /* 12 T_PAGEFLT */ 128 "", /* 13 unused */ 129 "alignment fault", /* 14 T_ALIGNFLT */ 130 "", /* 15 unused */ 131 "", /* 16 unused */ 132 "", /* 17 unused */ 133 "integer divide fault", /* 18 T_DIVIDE */ 134 "non-maskable interrupt trap", /* 19 T_NMI */ 135 "overflow trap", /* 20 T_OFLOW */ 136 "FPU bounds check fault", /* 21 T_BOUND */ 137 "FPU device not available", /* 22 T_DNA */ 138 "double fault", /* 23 T_DOUBLEFLT */ 139 "FPU operand fetch fault", /* 24 T_FPOPFLT */ 140 "invalid TSS fault", /* 25 T_TSSFLT */ 141 "segment not present fault", /* 26 T_SEGNPFLT */ 142 "stack fault", /* 27 T_STKFLT */ 143 "machine check trap", /* 28 T_MCHK */ 144 "SIMD floating-point exception", /* 29 T_XMMFLT */ 145 "reserved (unknown) fault", /* 30 T_RESERVED */ 146 }; 147 148 #ifdef DDB 149 static int ddb_on_nmi = 1; 150 SYSCTL_INT(_machdep, OID_AUTO, ddb_on_nmi, CTLFLAG_RW, 151 &ddb_on_nmi, 0, "Go to DDB on NMI"); 152 #endif 153 static int panic_on_nmi = 1; 154 SYSCTL_INT(_machdep, OID_AUTO, panic_on_nmi, CTLFLAG_RW, 155 &panic_on_nmi, 0, "Panic on NMI"); 156 static int fast_release; 157 SYSCTL_INT(_machdep, OID_AUTO, fast_release, CTLFLAG_RW, 158 &fast_release, 0, "Passive Release was optimal"); 159 static int slow_release; 160 SYSCTL_INT(_machdep, OID_AUTO, slow_release, CTLFLAG_RW, 161 &slow_release, 0, "Passive Release was nonoptimal"); 162 163 MALLOC_DEFINE(M_SYSMSG, "sysmsg", "sysmsg structure"); 164 extern int max_sysmsg; 165 166 /* 167 * Passively intercepts the thread switch function to increase 168 * the thread priority from a user priority to a kernel priority, reducing 169 * syscall and trap overhead for the case where no switch occurs. 170 * 171 * Synchronizes td_ucred with p_ucred. This is used by system calls, 172 * signal handling, faults, AST traps, and anything else that enters the 173 * kernel from userland and provides the kernel with a stable read-only 174 * copy of the process ucred. 175 */ 176 static __inline void 177 userenter(struct thread *curtd, struct proc *curp) 178 { 179 struct ucred *ocred; 180 struct ucred *ncred; 181 182 curtd->td_release = lwkt_passive_release; 183 184 if (curtd->td_ucred != curp->p_ucred) { 185 ncred = crhold(curp->p_ucred); 186 ocred = curtd->td_ucred; 187 curtd->td_ucred = ncred; 188 if (ocred) 189 crfree(ocred); 190 } 191 } 192 193 /* 194 * Handle signals, profiling, and other AST's and/or tasks that 195 * must be completed before we can return to or try to return to userland. 196 * 197 * Note that td_sticks is a 64 bit quantity, but there's no point doing 64 198 * arithmatic on the delta calculation so the absolute tick values are 199 * truncated to an integer. 200 */ 201 static void 202 userret(struct lwp *lp, struct trapframe *frame, int sticks) 203 { 204 struct proc *p = lp->lwp_proc; 205 int sig; 206 207 /* 208 * Charge system time if profiling. Note: times are in microseconds. 209 * This may do a copyout and block, so do it first even though it 210 * means some system time will be charged as user time. 211 */ 212 if (p->p_flags & P_PROFIL) { 213 addupc_task(p, frame->tf_rip, 214 (u_int)((int)lp->lwp_thread->td_sticks - sticks)); 215 } 216 217 recheck: 218 /* 219 * Specific on-return-to-usermode checks (LWP_MP_WEXIT, 220 * LWP_MP_VNLRU, etc). 221 */ 222 if (lp->lwp_mpflags & LWP_MP_URETMASK) 223 lwpuserret(lp); 224 225 /* 226 * Block here if we are in a stopped state. 227 */ 228 if (p->p_stat == SSTOP) { 229 lwkt_gettoken(&p->p_token); 230 tstop(); 231 lwkt_reltoken(&p->p_token); 232 goto recheck; 233 } 234 235 /* 236 * Post any pending upcalls. If running a virtual kernel be sure 237 * to restore the virtual kernel's vmspace before posting the upcall. 238 */ 239 if (p->p_flags & (P_SIGVTALRM | P_SIGPROF)) { 240 lwkt_gettoken(&p->p_token); 241 if (p->p_flags & P_SIGVTALRM) { 242 p->p_flags &= ~P_SIGVTALRM; 243 ksignal(p, SIGVTALRM); 244 } 245 if (p->p_flags & P_SIGPROF) { 246 p->p_flags &= ~P_SIGPROF; 247 ksignal(p, SIGPROF); 248 } 249 lwkt_reltoken(&p->p_token); 250 goto recheck; 251 } 252 253 /* 254 * Post any pending signals 255 * 256 * WARNING! postsig() can exit and not return. 257 */ 258 if ((sig = CURSIG_TRACE(lp)) != 0) { 259 lwkt_gettoken(&p->p_token); 260 postsig(sig); 261 lwkt_reltoken(&p->p_token); 262 goto recheck; 263 } 264 265 /* 266 * block here if we are swapped out, but still process signals 267 * (such as SIGKILL). proc0 (the swapin scheduler) is already 268 * aware of our situation, we do not have to wake it up. 269 */ 270 if (p->p_flags & P_SWAPPEDOUT) { 271 lwkt_gettoken(&p->p_token); 272 get_mplock(); 273 p->p_flags |= P_SWAPWAIT; 274 swapin_request(); 275 if (p->p_flags & P_SWAPWAIT) 276 tsleep(p, PCATCH, "SWOUT", 0); 277 p->p_flags &= ~P_SWAPWAIT; 278 rel_mplock(); 279 lwkt_reltoken(&p->p_token); 280 goto recheck; 281 } 282 283 /* 284 * In a multi-threaded program it is possible for a thread to change 285 * signal state during a system call which temporarily changes the 286 * signal mask. In this case postsig() might not be run and we 287 * have to restore the mask ourselves. 288 */ 289 if (lp->lwp_flags & LWP_OLDMASK) { 290 lp->lwp_flags &= ~LWP_OLDMASK; 291 lp->lwp_sigmask = lp->lwp_oldsigmask; 292 goto recheck; 293 } 294 } 295 296 /* 297 * Cleanup from userenter and any passive release that might have occured. 298 * We must reclaim the current-process designation before we can return 299 * to usermode. We also handle both LWKT and USER reschedule requests. 300 */ 301 static __inline void 302 userexit(struct lwp *lp) 303 { 304 struct thread *td = lp->lwp_thread; 305 /* globaldata_t gd = td->td_gd; */ 306 307 /* 308 * Handle stop requests at kernel priority. Any requests queued 309 * after this loop will generate another AST. 310 */ 311 while (lp->lwp_proc->p_stat == SSTOP) { 312 lwkt_gettoken(&lp->lwp_proc->p_token); 313 tstop(); 314 lwkt_reltoken(&lp->lwp_proc->p_token); 315 } 316 317 /* 318 * Reduce our priority in preparation for a return to userland. If 319 * our passive release function was still in place, our priority was 320 * never raised and does not need to be reduced. 321 */ 322 lwkt_passive_recover(td); 323 324 /* 325 * Become the current user scheduled process if we aren't already, 326 * and deal with reschedule requests and other factors. 327 */ 328 lp->lwp_proc->p_usched->acquire_curproc(lp); 329 /* WARNING: we may have migrated cpu's */ 330 /* gd = td->td_gd; */ 331 } 332 333 #if !defined(KTR_KERNENTRY) 334 #define KTR_KERNENTRY KTR_ALL 335 #endif 336 KTR_INFO_MASTER(kernentry); 337 KTR_INFO(KTR_KERNENTRY, kernentry, trap, 0, 338 "TRAP(pid %hd, tid %hd, trapno %ld, eva %lu)", 339 pid_t pid, lwpid_t tid, register_t trapno, vm_offset_t eva); 340 KTR_INFO(KTR_KERNENTRY, kernentry, trap_ret, 0, "TRAP_RET(pid %hd, tid %hd)", 341 pid_t pid, lwpid_t tid); 342 KTR_INFO(KTR_KERNENTRY, kernentry, syscall, 0, "SYSC(pid %hd, tid %hd, nr %ld)", 343 pid_t pid, lwpid_t tid, register_t trapno); 344 KTR_INFO(KTR_KERNENTRY, kernentry, syscall_ret, 0, "SYSRET(pid %hd, tid %hd, err %d)", 345 pid_t pid, lwpid_t tid, int err); 346 KTR_INFO(KTR_KERNENTRY, kernentry, fork_ret, 0, "FORKRET(pid %hd, tid %hd)", 347 pid_t pid, lwpid_t tid); 348 349 /* 350 * Exception, fault, and trap interface to the kernel. 351 * This common code is called from assembly language IDT gate entry 352 * routines that prepare a suitable stack frame, and restore this 353 * frame after the exception has been processed. 354 * 355 * This function is also called from doreti in an interlock to handle ASTs. 356 * For example: hardwareint->INTROUTINE->(set ast)->doreti->trap 357 * 358 * NOTE! We have to retrieve the fault address prior to obtaining the 359 * MP lock because get_mplock() may switch out. YYY cr2 really ought 360 * to be retrieved by the assembly code, not here. 361 * 362 * XXX gd_trap_nesting_level currently prevents lwkt_switch() from panicing 363 * if an attempt is made to switch from a fast interrupt or IPI. This is 364 * necessary to properly take fatal kernel traps on SMP machines if 365 * get_mplock() has to block. 366 */ 367 368 void 369 user_trap(struct trapframe *frame) 370 { 371 struct globaldata *gd = mycpu; 372 struct thread *td = gd->gd_curthread; 373 struct lwp *lp = td->td_lwp; 374 struct proc *p; 375 int sticks = 0; 376 int i = 0, ucode = 0, type, code; 377 int have_mplock = 0; 378 #ifdef INVARIANTS 379 int crit_count = td->td_critcount; 380 lwkt_tokref_t curstop = td->td_toks_stop; 381 #endif 382 vm_offset_t eva; 383 384 p = td->td_proc; 385 386 if (frame->tf_trapno == T_PAGEFLT) 387 eva = frame->tf_addr; 388 else 389 eva = 0; 390 #if 0 391 kprintf("USER_TRAP AT %08lx xflags %ld trapno %ld eva %08lx\n", 392 frame->tf_rip, frame->tf_xflags, frame->tf_trapno, eva); 393 #endif 394 395 /* 396 * Everything coming from user mode runs through user_trap, 397 * including system calls. 398 */ 399 if (frame->tf_trapno == T_FAST_SYSCALL) { 400 syscall2(frame); 401 return; 402 } 403 404 KTR_LOG(kernentry_trap, lp->lwp_proc->p_pid, lp->lwp_tid, 405 frame->tf_trapno, eva); 406 407 #ifdef DDB 408 if (db_active) { 409 eva = (frame->tf_trapno == T_PAGEFLT ? rcr2() : 0); 410 ++gd->gd_trap_nesting_level; 411 MAKEMPSAFE(have_mplock); 412 trap_fatal(frame, TRUE, eva); 413 --gd->gd_trap_nesting_level; 414 goto out2; 415 } 416 #endif 417 418 type = frame->tf_trapno; 419 code = frame->tf_err; 420 421 userenter(td, p); 422 423 sticks = (int)td->td_sticks; 424 lp->lwp_md.md_regs = frame; 425 426 switch (type) { 427 case T_PRIVINFLT: /* privileged instruction fault */ 428 i = SIGILL; 429 ucode = ILL_PRVOPC; 430 break; 431 432 case T_BPTFLT: /* bpt instruction fault */ 433 case T_TRCTRAP: /* trace trap */ 434 frame->tf_rflags &= ~PSL_T; 435 i = SIGTRAP; 436 ucode = (type == T_TRCTRAP ? TRAP_TRACE : TRAP_BRKPT); 437 break; 438 439 case T_ARITHTRAP: /* arithmetic trap */ 440 ucode = code; 441 i = SIGFPE; 442 break; 443 444 case T_ASTFLT: /* Allow process switch */ 445 mycpu->gd_cnt.v_soft++; 446 if (mycpu->gd_reqflags & RQF_AST_OWEUPC) { 447 atomic_clear_int(&mycpu->gd_reqflags, RQF_AST_OWEUPC); 448 addupc_task(p, p->p_prof.pr_addr, p->p_prof.pr_ticks); 449 } 450 goto out; 451 452 /* 453 * The following two traps can happen in 454 * vm86 mode, and, if so, we want to handle 455 * them specially. 456 */ 457 case T_PROTFLT: /* general protection fault */ 458 case T_STKFLT: /* stack fault */ 459 #if 0 460 if (frame->tf_eflags & PSL_VM) { 461 i = vm86_emulate((struct vm86frame *)frame); 462 if (i == 0) 463 goto out; 464 break; 465 } 466 #endif 467 /* FALL THROUGH */ 468 469 case T_SEGNPFLT: /* segment not present fault */ 470 case T_TSSFLT: /* invalid TSS fault */ 471 case T_DOUBLEFLT: /* double fault */ 472 default: 473 i = SIGBUS; 474 ucode = code + BUS_SEGM_FAULT ; 475 break; 476 477 case T_PAGEFLT: /* page fault */ 478 MAKEMPSAFE(have_mplock); 479 i = trap_pfault(frame, TRUE, eva); 480 if (i == -1 || i == 0) 481 goto out; 482 483 484 if (i == SIGSEGV) 485 ucode = SEGV_MAPERR; 486 else { 487 i = SIGSEGV; 488 ucode = SEGV_ACCERR; 489 } 490 break; 491 492 case T_DIVIDE: /* integer divide fault */ 493 ucode = FPE_INTDIV; 494 i = SIGFPE; 495 break; 496 497 #if NISA > 0 498 case T_NMI: 499 MAKEMPSAFE(have_mplock); 500 /* machine/parity/power fail/"kitchen sink" faults */ 501 if (isa_nmi(code) == 0) { 502 #ifdef DDB 503 /* 504 * NMI can be hooked up to a pushbutton 505 * for debugging. 506 */ 507 if (ddb_on_nmi) { 508 kprintf ("NMI ... going to debugger\n"); 509 kdb_trap(type, 0, frame); 510 } 511 #endif /* DDB */ 512 goto out2; 513 } else if (panic_on_nmi) 514 panic("NMI indicates hardware failure"); 515 break; 516 #endif /* NISA > 0 */ 517 518 case T_OFLOW: /* integer overflow fault */ 519 ucode = FPE_INTOVF; 520 i = SIGFPE; 521 break; 522 523 case T_BOUND: /* bounds check fault */ 524 ucode = FPE_FLTSUB; 525 i = SIGFPE; 526 break; 527 528 case T_DNA: 529 /* 530 * Virtual kernel intercept - pass the DNA exception 531 * to the (emulated) virtual kernel if it asked to handle 532 * it. This occurs when the virtual kernel is holding 533 * onto the FP context for a different emulated 534 * process then the one currently running. 535 * 536 * We must still call npxdna() since we may have 537 * saved FP state that the (emulated) virtual kernel 538 * needs to hand over to a different emulated process. 539 */ 540 if (lp->lwp_vkernel && lp->lwp_vkernel->ve && 541 (td->td_pcb->pcb_flags & FP_VIRTFP) 542 ) { 543 npxdna(frame); 544 break; 545 } 546 547 /* 548 * The kernel may have switched out the FP unit's 549 * state, causing the user process to take a fault 550 * when it tries to use the FP unit. Restore the 551 * state here 552 */ 553 if (npxdna(frame)) 554 goto out; 555 if (!pmath_emulate) { 556 i = SIGFPE; 557 ucode = FPE_FPU_NP_TRAP; 558 break; 559 } 560 i = (*pmath_emulate)(frame); 561 if (i == 0) { 562 if (!(frame->tf_rflags & PSL_T)) 563 goto out2; 564 frame->tf_rflags &= ~PSL_T; 565 i = SIGTRAP; 566 } 567 /* else ucode = emulator_only_knows() XXX */ 568 break; 569 570 case T_FPOPFLT: /* FPU operand fetch fault */ 571 ucode = T_FPOPFLT; 572 i = SIGILL; 573 break; 574 575 case T_XMMFLT: /* SIMD floating-point exception */ 576 ucode = 0; /* XXX */ 577 i = SIGFPE; 578 break; 579 } 580 581 /* 582 * Virtual kernel intercept - if the fault is directly related to a 583 * VM context managed by a virtual kernel then let the virtual kernel 584 * handle it. 585 */ 586 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) { 587 vkernel_trap(lp, frame); 588 goto out; 589 } 590 591 /* 592 * Translate fault for emulators (e.g. Linux) 593 */ 594 if (*p->p_sysent->sv_transtrap) 595 i = (*p->p_sysent->sv_transtrap)(i, type); 596 597 MAKEMPSAFE(have_mplock); 598 trapsignal(lp, i, ucode); 599 600 #ifdef DEBUG 601 if (type <= MAX_TRAP_MSG) { 602 uprintf("fatal process exception: %s", 603 trap_msg[type]); 604 if ((type == T_PAGEFLT) || (type == T_PROTFLT)) 605 uprintf(", fault VA = 0x%lx", (u_long)eva); 606 uprintf("\n"); 607 } 608 #endif 609 610 out: 611 userret(lp, frame, sticks); 612 userexit(lp); 613 out2: ; 614 if (have_mplock) 615 rel_mplock(); 616 KTR_LOG(kernentry_trap_ret, lp->lwp_proc->p_pid, lp->lwp_tid); 617 #ifdef INVARIANTS 618 KASSERT(crit_count == td->td_critcount, 619 ("trap: critical section count mismatch! %d/%d", 620 crit_count, td->td_pri)); 621 KASSERT(curstop == td->td_toks_stop, 622 ("trap: extra tokens held after trap! %ld/%ld", 623 curstop - &td->td_toks_base, 624 td->td_toks_stop - &td->td_toks_base)); 625 #endif 626 } 627 628 void 629 kern_trap(struct trapframe *frame) 630 { 631 struct globaldata *gd = mycpu; 632 struct thread *td = gd->gd_curthread; 633 struct lwp *lp; 634 struct proc *p; 635 int i = 0, ucode = 0, type, code; 636 int have_mplock = 0; 637 #ifdef INVARIANTS 638 int crit_count = td->td_critcount; 639 lwkt_tokref_t curstop = td->td_toks_stop; 640 #endif 641 vm_offset_t eva; 642 643 lp = td->td_lwp; 644 p = td->td_proc; 645 646 if (frame->tf_trapno == T_PAGEFLT) 647 eva = frame->tf_addr; 648 else 649 eva = 0; 650 651 #ifdef DDB 652 if (db_active) { 653 ++gd->gd_trap_nesting_level; 654 MAKEMPSAFE(have_mplock); 655 trap_fatal(frame, FALSE, eva); 656 --gd->gd_trap_nesting_level; 657 goto out2; 658 } 659 #endif 660 661 type = frame->tf_trapno; 662 code = frame->tf_err; 663 664 #if 0 665 kernel_trap: 666 #endif 667 /* kernel trap */ 668 669 switch (type) { 670 case T_PAGEFLT: /* page fault */ 671 MAKEMPSAFE(have_mplock); 672 trap_pfault(frame, FALSE, eva); 673 goto out2; 674 675 case T_DNA: 676 /* 677 * The kernel may be using npx for copying or other 678 * purposes. 679 */ 680 panic("kernel NPX should not happen"); 681 if (npxdna(frame)) 682 goto out2; 683 break; 684 685 case T_PROTFLT: /* general protection fault */ 686 case T_SEGNPFLT: /* segment not present fault */ 687 /* 688 * Invalid segment selectors and out of bounds 689 * %eip's and %esp's can be set up in user mode. 690 * This causes a fault in kernel mode when the 691 * kernel tries to return to user mode. We want 692 * to get this fault so that we can fix the 693 * problem here and not have to check all the 694 * selectors and pointers when the user changes 695 * them. 696 */ 697 if (mycpu->gd_intr_nesting_level == 0) { 698 if (td->td_pcb->pcb_onfault) { 699 frame->tf_rip = 700 (register_t)td->td_pcb->pcb_onfault; 701 goto out2; 702 } 703 } 704 break; 705 706 case T_TSSFLT: 707 /* 708 * PSL_NT can be set in user mode and isn't cleared 709 * automatically when the kernel is entered. This 710 * causes a TSS fault when the kernel attempts to 711 * `iret' because the TSS link is uninitialized. We 712 * want to get this fault so that we can fix the 713 * problem here and not every time the kernel is 714 * entered. 715 */ 716 if (frame->tf_rflags & PSL_NT) { 717 frame->tf_rflags &= ~PSL_NT; 718 goto out2; 719 } 720 break; 721 722 case T_TRCTRAP: /* trace trap */ 723 #if 0 724 if (frame->tf_eip == (int)IDTVEC(syscall)) { 725 /* 726 * We've just entered system mode via the 727 * syscall lcall. Continue single stepping 728 * silently until the syscall handler has 729 * saved the flags. 730 */ 731 goto out2; 732 } 733 if (frame->tf_eip == (int)IDTVEC(syscall) + 1) { 734 /* 735 * The syscall handler has now saved the 736 * flags. Stop single stepping it. 737 */ 738 frame->tf_eflags &= ~PSL_T; 739 goto out2; 740 } 741 #endif 742 #if 0 743 /* 744 * Ignore debug register trace traps due to 745 * accesses in the user's address space, which 746 * can happen under several conditions such as 747 * if a user sets a watchpoint on a buffer and 748 * then passes that buffer to a system call. 749 * We still want to get TRCTRAPS for addresses 750 * in kernel space because that is useful when 751 * debugging the kernel. 752 */ 753 if (user_dbreg_trap()) { 754 /* 755 * Reset breakpoint bits because the 756 * processor doesn't 757 */ 758 load_dr6(rdr6() & 0xfffffff0); 759 goto out2; 760 } 761 #endif 762 /* 763 * Fall through (TRCTRAP kernel mode, kernel address) 764 */ 765 case T_BPTFLT: 766 /* 767 * If DDB is enabled, let it handle the debugger trap. 768 * Otherwise, debugger traps "can't happen". 769 */ 770 #ifdef DDB 771 MAKEMPSAFE(have_mplock); 772 if (kdb_trap (type, 0, frame)) 773 goto out2; 774 #endif 775 break; 776 case T_DIVIDE: 777 MAKEMPSAFE(have_mplock); 778 trap_fatal(frame, FALSE, eva); 779 goto out2; 780 case T_NMI: 781 MAKEMPSAFE(have_mplock); 782 trap_fatal(frame, FALSE, eva); 783 goto out2; 784 case T_SYSCALL80: 785 case T_FAST_SYSCALL: 786 /* 787 * Ignore this trap generated from a spurious SIGTRAP. 788 * 789 * single stepping in / syscalls leads to spurious / SIGTRAP 790 * so ignore 791 * 792 * Haiku (c) 2007 Simon 'corecode' Schubert 793 */ 794 goto out2; 795 } 796 797 /* 798 * Translate fault for emulators (e.g. Linux) 799 */ 800 if (*p->p_sysent->sv_transtrap) 801 i = (*p->p_sysent->sv_transtrap)(i, type); 802 803 MAKEMPSAFE(have_mplock); 804 trapsignal(lp, i, ucode); 805 806 #ifdef DEBUG 807 if (type <= MAX_TRAP_MSG) { 808 uprintf("fatal process exception: %s", 809 trap_msg[type]); 810 if ((type == T_PAGEFLT) || (type == T_PROTFLT)) 811 uprintf(", fault VA = 0x%lx", (u_long)eva); 812 uprintf("\n"); 813 } 814 #endif 815 816 out2: 817 ; 818 if (have_mplock) 819 rel_mplock(); 820 #ifdef INVARIANTS 821 KASSERT(crit_count == td->td_critcount, 822 ("trap: critical section count mismatch! %d/%d", 823 crit_count, td->td_pri)); 824 KASSERT(curstop == td->td_toks_stop, 825 ("trap: extra tokens held after trap! %ld/%ld", 826 curstop - &td->td_toks_base, 827 td->td_toks_stop - &td->td_toks_base)); 828 #endif 829 } 830 831 int 832 trap_pfault(struct trapframe *frame, int usermode, vm_offset_t eva) 833 { 834 vm_offset_t va; 835 struct vmspace *vm = NULL; 836 vm_map_t map = 0; 837 int rv = 0; 838 vm_prot_t ftype; 839 thread_t td = curthread; 840 struct lwp *lp = td->td_lwp; 841 int fault_flags; 842 843 va = trunc_page(eva); 844 if (usermode == FALSE) { 845 /* 846 * This is a fault on kernel virtual memory. 847 */ 848 map = &kernel_map; 849 } else { 850 /* 851 * This is a fault on non-kernel virtual memory. 852 * vm is initialized above to NULL. If curproc is NULL 853 * or curproc->p_vmspace is NULL the fault is fatal. 854 */ 855 if (lp != NULL) 856 vm = lp->lwp_vmspace; 857 858 if (vm == NULL) 859 goto nogo; 860 861 map = &vm->vm_map; 862 } 863 864 if (frame->tf_err & PGEX_W) 865 ftype = VM_PROT_READ | VM_PROT_WRITE; 866 else 867 ftype = VM_PROT_READ; 868 869 if (map != &kernel_map) { 870 /* 871 * Keep swapout from messing with us during this 872 * critical time. 873 */ 874 PHOLD(lp->lwp_proc); 875 876 /* 877 * Grow the stack if necessary 878 */ 879 /* grow_stack returns false only if va falls into 880 * a growable stack region and the stack growth 881 * fails. It returns true if va was not within 882 * a growable stack region, or if the stack 883 * growth succeeded. 884 */ 885 if (!grow_stack (lp->lwp_proc, va)) { 886 rv = KERN_FAILURE; 887 PRELE(lp->lwp_proc); 888 goto nogo; 889 } 890 891 fault_flags = 0; 892 if (usermode) 893 fault_flags |= VM_FAULT_BURST; 894 if (ftype & VM_PROT_WRITE) 895 fault_flags |= VM_FAULT_DIRTY; 896 else 897 fault_flags |= VM_FAULT_NORMAL; 898 rv = vm_fault(map, va, ftype, fault_flags); 899 900 PRELE(lp->lwp_proc); 901 } else { 902 /* 903 * Don't have to worry about process locking or stacks in the kernel. 904 */ 905 rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL); 906 } 907 908 if (rv == KERN_SUCCESS) 909 return (0); 910 nogo: 911 if (!usermode) { 912 if (td->td_gd->gd_intr_nesting_level == 0 && 913 td->td_pcb->pcb_onfault) { 914 frame->tf_rip = (register_t)td->td_pcb->pcb_onfault; 915 return (0); 916 } 917 trap_fatal(frame, usermode, eva); 918 return (-1); 919 } 920 921 /* 922 * NOTE: on x86_64 we have a tf_addr field in the trapframe, no 923 * kludge is needed to pass the fault address to signal handlers. 924 */ 925 struct proc *p = td->td_proc; 926 kprintf("seg-fault accessing address %p rip=%p pid=%d p_comm=%s\n", 927 (void *)va, (void *)frame->tf_rip, p->p_pid, p->p_comm); 928 /* Debugger("seg-fault"); */ 929 930 return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV); 931 } 932 933 static void 934 trap_fatal(struct trapframe *frame, int usermode, vm_offset_t eva) 935 { 936 int code, type, ss; 937 long rsp; 938 939 code = frame->tf_xflags; 940 type = frame->tf_trapno; 941 942 if (type <= MAX_TRAP_MSG) { 943 kprintf("\n\nFatal trap %d: %s while in %s mode\n", 944 type, trap_msg[type], 945 (usermode ? "user" : "kernel")); 946 } 947 /* two separate prints in case of a trap on an unmapped page */ 948 kprintf("cpuid = %d\n", mycpu->gd_cpuid); 949 if (type == T_PAGEFLT) { 950 kprintf("fault virtual address = %p\n", (void *)eva); 951 kprintf("fault code = %s %s, %s\n", 952 usermode ? "user" : "supervisor", 953 code & PGEX_W ? "write" : "read", 954 code & PGEX_P ? "protection violation" : "page not present"); 955 } 956 kprintf("instruction pointer = 0x%lx:0x%lx\n", 957 frame->tf_cs & 0xffff, frame->tf_rip); 958 if (usermode) { 959 ss = frame->tf_ss & 0xffff; 960 rsp = frame->tf_rsp; 961 } else { 962 ss = GSEL(GDATA_SEL, SEL_KPL); 963 rsp = (long)&frame->tf_rsp; 964 } 965 kprintf("stack pointer = 0x%x:0x%lx\n", ss, rsp); 966 kprintf("frame pointer = 0x%x:0x%lx\n", ss, frame->tf_rbp); 967 kprintf("processor eflags = "); 968 if (frame->tf_rflags & PSL_T) 969 kprintf("trace trap, "); 970 if (frame->tf_rflags & PSL_I) 971 kprintf("interrupt enabled, "); 972 if (frame->tf_rflags & PSL_NT) 973 kprintf("nested task, "); 974 if (frame->tf_rflags & PSL_RF) 975 kprintf("resume, "); 976 #if 0 977 if (frame->tf_eflags & PSL_VM) 978 kprintf("vm86, "); 979 #endif 980 kprintf("IOPL = %jd\n", (intmax_t)((frame->tf_rflags & PSL_IOPL) >> 12)); 981 kprintf("current process = "); 982 if (curproc) { 983 kprintf("%lu (%s)\n", 984 (u_long)curproc->p_pid, curproc->p_comm ? 985 curproc->p_comm : ""); 986 } else { 987 kprintf("Idle\n"); 988 } 989 kprintf("current thread = pri %d ", curthread->td_pri); 990 if (curthread->td_critcount) 991 kprintf("(CRIT)"); 992 kprintf("\n"); 993 /** 994 * XXX FIXME: 995 * we probably SHOULD have stopped the other CPUs before now! 996 * another CPU COULD have been touching cpl at this moment... 997 */ 998 kprintf(" <- SMP: XXX"); 999 kprintf("\n"); 1000 1001 #ifdef KDB 1002 if (kdb_trap(&psl)) 1003 return; 1004 #endif 1005 #ifdef DDB 1006 if ((debugger_on_panic || db_active) && kdb_trap(type, code, frame)) 1007 return; 1008 #endif 1009 kprintf("trap number = %d\n", type); 1010 if (type <= MAX_TRAP_MSG) 1011 panic("%s", trap_msg[type]); 1012 else 1013 panic("unknown/reserved trap"); 1014 } 1015 1016 /* 1017 * Double fault handler. Called when a fault occurs while writing 1018 * a frame for a trap/exception onto the stack. This usually occurs 1019 * when the stack overflows (such is the case with infinite recursion, 1020 * for example). 1021 * 1022 * XXX Note that the current PTD gets replaced by IdlePTD when the 1023 * task switch occurs. This means that the stack that was active at 1024 * the time of the double fault is not available at <kstack> unless 1025 * the machine was idle when the double fault occurred. The downside 1026 * of this is that "trace <ebp>" in ddb won't work. 1027 */ 1028 void 1029 dblfault_handler(void) 1030 { 1031 #if JG 1032 struct mdglobaldata *gd = mdcpu; 1033 #endif 1034 1035 kprintf("\nFatal double fault:\n"); 1036 #if JG 1037 kprintf("rip = 0x%lx\n", gd->gd_common_tss.tss_rip); 1038 kprintf("rsp = 0x%lx\n", gd->gd_common_tss.tss_rsp); 1039 kprintf("rbp = 0x%lx\n", gd->gd_common_tss.tss_rbp); 1040 #endif 1041 /* two separate prints in case of a trap on an unmapped page */ 1042 kprintf("cpuid = %d\n", mycpu->gd_cpuid); 1043 panic("double fault"); 1044 } 1045 1046 /* 1047 * Compensate for 386 brain damage (missing URKR). 1048 * This is a little simpler than the pagefault handler in trap() because 1049 * it the page tables have already been faulted in and high addresses 1050 * are thrown out early for other reasons. 1051 */ 1052 int 1053 trapwrite(unsigned addr) 1054 { 1055 struct lwp *lp; 1056 vm_offset_t va; 1057 struct vmspace *vm; 1058 int rv; 1059 1060 va = trunc_page((vm_offset_t)addr); 1061 /* 1062 * XXX - MAX is END. Changed > to >= for temp. fix. 1063 */ 1064 if (va >= VM_MAX_USER_ADDRESS) 1065 return (1); 1066 1067 lp = curthread->td_lwp; 1068 vm = lp->lwp_vmspace; 1069 1070 PHOLD(lp->lwp_proc); 1071 1072 if (!grow_stack (lp->lwp_proc, va)) { 1073 PRELE(lp->lwp_proc); 1074 return (1); 1075 } 1076 1077 /* 1078 * fault the data page 1079 */ 1080 rv = vm_fault(&vm->vm_map, va, VM_PROT_WRITE, VM_FAULT_DIRTY); 1081 1082 PRELE(lp->lwp_proc); 1083 1084 if (rv != KERN_SUCCESS) 1085 return 1; 1086 1087 return (0); 1088 } 1089 1090 /* 1091 * syscall2 - MP aware system call request C handler 1092 * 1093 * A system call is essentially treated as a trap except that the 1094 * MP lock is not held on entry or return. We are responsible for 1095 * obtaining the MP lock if necessary and for handling ASTs 1096 * (e.g. a task switch) prior to return. 1097 * 1098 * In general, only simple access and manipulation of curproc and 1099 * the current stack is allowed without having to hold MP lock. 1100 * 1101 * MPSAFE - note that large sections of this routine are run without 1102 * the MP lock. 1103 */ 1104 void 1105 syscall2(struct trapframe *frame) 1106 { 1107 struct thread *td = curthread; 1108 struct proc *p = td->td_proc; 1109 struct lwp *lp = td->td_lwp; 1110 caddr_t params; 1111 struct sysent *callp; 1112 register_t orig_tf_rflags; 1113 int sticks; 1114 int error; 1115 int narg; 1116 #ifdef INVARIANTS 1117 int crit_count = td->td_critcount; 1118 lwkt_tokref_t curstop = td->td_toks_stop; 1119 #endif 1120 int have_mplock = 0; 1121 register_t *argp; 1122 u_int code; 1123 int reg, regcnt; 1124 union sysunion args; 1125 register_t *argsdst; 1126 1127 mycpu->gd_cnt.v_syscall++; 1128 1129 KTR_LOG(kernentry_syscall, lp->lwp_proc->p_pid, lp->lwp_tid, 1130 frame->tf_rax); 1131 1132 userenter(td, p); /* lazy raise our priority */ 1133 1134 reg = 0; 1135 regcnt = 6; 1136 /* 1137 * Misc 1138 */ 1139 sticks = (int)td->td_sticks; 1140 orig_tf_rflags = frame->tf_rflags; 1141 1142 /* 1143 * Virtual kernel intercept - if a VM context managed by a virtual 1144 * kernel issues a system call the virtual kernel handles it, not us. 1145 * Restore the virtual kernel context and return from its system 1146 * call. The current frame is copied out to the virtual kernel. 1147 */ 1148 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) { 1149 vkernel_trap(lp, frame); 1150 error = EJUSTRETURN; 1151 goto out; 1152 } 1153 1154 /* 1155 * Get the system call parameters and account for time 1156 */ 1157 lp->lwp_md.md_regs = frame; 1158 params = (caddr_t)frame->tf_rsp + sizeof(register_t); 1159 code = frame->tf_rax; 1160 1161 if (p->p_sysent->sv_prepsyscall) { 1162 (*p->p_sysent->sv_prepsyscall)( 1163 frame, (int *)(&args.nosys.sysmsg + 1), 1164 &code, ¶ms); 1165 } else { 1166 if (code == SYS_syscall || code == SYS___syscall) { 1167 code = frame->tf_rdi; 1168 reg++; 1169 regcnt--; 1170 } 1171 } 1172 1173 if (p->p_sysent->sv_mask) 1174 code &= p->p_sysent->sv_mask; 1175 1176 if (code >= p->p_sysent->sv_size) 1177 callp = &p->p_sysent->sv_table[0]; 1178 else 1179 callp = &p->p_sysent->sv_table[code]; 1180 1181 narg = callp->sy_narg & SYF_ARGMASK; 1182 1183 /* 1184 * On x86_64 we get up to six arguments in registers. The rest are 1185 * on the stack. The first six members of 'struct trapframe' happen 1186 * to be the registers used to pass arguments, in exactly the right 1187 * order. 1188 */ 1189 argp = &frame->tf_rdi; 1190 argp += reg; 1191 argsdst = (register_t *)(&args.nosys.sysmsg + 1); 1192 /* 1193 * JG can we overflow the space pointed to by 'argsdst' 1194 * either with 'bcopy' or with 'copyin'? 1195 */ 1196 bcopy(argp, argsdst, sizeof(register_t) * regcnt); 1197 /* 1198 * copyin is MP aware, but the tracing code is not 1199 */ 1200 if (narg > regcnt) { 1201 KASSERT(params != NULL, ("copyin args with no params!")); 1202 error = copyin(params, &argsdst[regcnt], 1203 (narg - regcnt) * sizeof(register_t)); 1204 if (error) { 1205 #ifdef KTRACE 1206 if (KTRPOINT(td, KTR_SYSCALL)) { 1207 MAKEMPSAFE(have_mplock); 1208 1209 ktrsyscall(lp, code, narg, 1210 (void *)(&args.nosys.sysmsg + 1)); 1211 } 1212 #endif 1213 goto bad; 1214 } 1215 } 1216 1217 #ifdef KTRACE 1218 if (KTRPOINT(td, KTR_SYSCALL)) { 1219 MAKEMPSAFE(have_mplock); 1220 ktrsyscall(lp, code, narg, (void *)(&args.nosys.sysmsg + 1)); 1221 } 1222 #endif 1223 1224 /* 1225 * Default return value is 0 (will be copied to %rax). Double-value 1226 * returns use %rax and %rdx. %rdx is left unchanged for system 1227 * calls which return only one result. 1228 */ 1229 args.sysmsg_fds[0] = 0; 1230 args.sysmsg_fds[1] = frame->tf_rdx; 1231 1232 /* 1233 * The syscall might manipulate the trap frame. If it does it 1234 * will probably return EJUSTRETURN. 1235 */ 1236 args.sysmsg_frame = frame; 1237 1238 STOPEVENT(p, S_SCE, narg); /* MP aware */ 1239 1240 /* 1241 * NOTE: All system calls run MPSAFE now. The system call itself 1242 * is responsible for getting the MP lock. 1243 */ 1244 error = (*callp->sy_call)(&args); 1245 1246 #if 0 1247 kprintf("system call %d returned %d\n", code, error); 1248 #endif 1249 1250 out: 1251 /* 1252 * MP SAFE (we may or may not have the MP lock at this point) 1253 */ 1254 switch (error) { 1255 case 0: 1256 /* 1257 * Reinitialize proc pointer `p' as it may be different 1258 * if this is a child returning from fork syscall. 1259 */ 1260 p = curproc; 1261 lp = curthread->td_lwp; 1262 frame->tf_rax = args.sysmsg_fds[0]; 1263 frame->tf_rdx = args.sysmsg_fds[1]; 1264 frame->tf_rflags &= ~PSL_C; 1265 break; 1266 case ERESTART: 1267 /* 1268 * Reconstruct pc, we know that 'syscall' is 2 bytes. 1269 * We have to do a full context restore so that %r10 1270 * (which was holding the value of %rcx) is restored for 1271 * the next iteration. 1272 */ 1273 frame->tf_rip -= frame->tf_err; 1274 frame->tf_r10 = frame->tf_rcx; 1275 break; 1276 case EJUSTRETURN: 1277 break; 1278 case EASYNC: 1279 panic("Unexpected EASYNC return value (for now)"); 1280 default: 1281 bad: 1282 if (p->p_sysent->sv_errsize) { 1283 if (error >= p->p_sysent->sv_errsize) 1284 error = -1; /* XXX */ 1285 else 1286 error = p->p_sysent->sv_errtbl[error]; 1287 } 1288 frame->tf_rax = error; 1289 frame->tf_rflags |= PSL_C; 1290 break; 1291 } 1292 1293 /* 1294 * Traced syscall. trapsignal() is not MP aware. 1295 */ 1296 if (orig_tf_rflags & PSL_T) { 1297 MAKEMPSAFE(have_mplock); 1298 frame->tf_rflags &= ~PSL_T; 1299 trapsignal(lp, SIGTRAP, 0); 1300 } 1301 1302 /* 1303 * Handle reschedule and other end-of-syscall issues 1304 */ 1305 userret(lp, frame, sticks); 1306 1307 #ifdef KTRACE 1308 if (KTRPOINT(td, KTR_SYSRET)) { 1309 MAKEMPSAFE(have_mplock); 1310 ktrsysret(lp, code, error, args.sysmsg_result); 1311 } 1312 #endif 1313 1314 /* 1315 * This works because errno is findable through the 1316 * register set. If we ever support an emulation where this 1317 * is not the case, this code will need to be revisited. 1318 */ 1319 STOPEVENT(p, S_SCX, code); 1320 1321 userexit(lp); 1322 /* 1323 * Release the MP lock if we had to get it 1324 */ 1325 if (have_mplock) 1326 rel_mplock(); 1327 KTR_LOG(kernentry_syscall_ret, lp->lwp_proc->p_pid, lp->lwp_tid, error); 1328 #ifdef INVARIANTS 1329 KASSERT(&td->td_toks_base == td->td_toks_stop, 1330 ("syscall: critical section count mismatch! %d/%d", 1331 crit_count, td->td_pri)); 1332 KASSERT(curstop == td->td_toks_stop, 1333 ("syscall: extra tokens held after trap! %ld", 1334 td->td_toks_stop - &td->td_toks_base)); 1335 #endif 1336 } 1337 1338 /* 1339 * NOTE: mplock not held at any point 1340 */ 1341 void 1342 fork_return(struct lwp *lp, struct trapframe *frame) 1343 { 1344 frame->tf_rax = 0; /* Child returns zero */ 1345 frame->tf_rflags &= ~PSL_C; /* success */ 1346 frame->tf_rdx = 1; 1347 1348 generic_lwp_return(lp, frame); 1349 KTR_LOG(kernentry_fork_ret, lp->lwp_proc->p_pid, lp->lwp_tid); 1350 } 1351 1352 /* 1353 * Simplified back end of syscall(), used when returning from fork() 1354 * directly into user mode. 1355 * 1356 * This code will return back into the fork trampoline code which then 1357 * runs doreti. 1358 * 1359 * NOTE: The mplock is not held at any point. 1360 */ 1361 void 1362 generic_lwp_return(struct lwp *lp, struct trapframe *frame) 1363 { 1364 struct proc *p = lp->lwp_proc; 1365 1366 /* 1367 * Newly forked processes are given a kernel priority. We have to 1368 * adjust the priority to a normal user priority and fake entry 1369 * into the kernel (call userenter()) to install a passive release 1370 * function just in case userret() decides to stop the process. This 1371 * can occur when ^Z races a fork. If we do not install the passive 1372 * release function the current process designation will not be 1373 * released when the thread goes to sleep. 1374 */ 1375 lwkt_setpri_self(TDPRI_USER_NORM); 1376 userenter(lp->lwp_thread, p); 1377 userret(lp, frame, 0); 1378 #ifdef KTRACE 1379 if (KTRPOINT(lp->lwp_thread, KTR_SYSRET)) 1380 ktrsysret(lp, SYS_fork, 0, 0); 1381 #endif 1382 lp->lwp_flags |= LWP_PASSIVE_ACQ; 1383 userexit(lp); 1384 lp->lwp_flags &= ~LWP_PASSIVE_ACQ; 1385 } 1386 1387 /* 1388 * doreti has turned into this. The frame is directly on the stack. We 1389 * pull everything else we need (fpu and tls context) from the current 1390 * thread. 1391 * 1392 * Note on fpu interactions: In a virtual kernel, the fpu context for 1393 * an emulated user mode process is not shared with the virtual kernel's 1394 * fpu context, so we only have to 'stack' fpu contexts within the virtual 1395 * kernel itself, and not even then since the signal() contexts that we care 1396 * about save and restore the FPU state (I think anyhow). 1397 * 1398 * vmspace_ctl() returns an error only if it had problems instaling the 1399 * context we supplied or problems copying data to/from our VM space. 1400 */ 1401 void 1402 go_user(struct intrframe *frame) 1403 { 1404 struct trapframe *tf = (void *)&frame->if_rdi; 1405 int r; 1406 1407 /* 1408 * Interrupts may be disabled on entry, make sure all signals 1409 * can be received before beginning our loop. 1410 */ 1411 sigsetmask(0); 1412 1413 /* 1414 * Switch to the current simulated user process, then call 1415 * user_trap() when we break out of it (usually due to a signal). 1416 */ 1417 for (;;) { 1418 /* 1419 * Tell the real kernel whether it is ok to use the FP 1420 * unit or not. 1421 */ 1422 if (mdcpu->gd_npxthread == curthread) { 1423 tf->tf_xflags &= ~PGEX_FPFAULT; 1424 } else { 1425 tf->tf_xflags |= PGEX_FPFAULT; 1426 } 1427 1428 /* 1429 * Run emulated user process context. This call interlocks 1430 * with new mailbox signals. 1431 * 1432 * Set PGEX_U unconditionally, indicating a user frame (the 1433 * bit is normally set only by T_PAGEFLT). 1434 */ 1435 r = vmspace_ctl(&curproc->p_vmspace->vm_pmap, VMSPACE_CTL_RUN, 1436 tf, &curthread->td_savevext); 1437 frame->if_xflags |= PGEX_U; 1438 #if 0 1439 kprintf("GO USER %d trap %ld EVA %08lx RIP %08lx RSP %08lx XFLAGS %02lx/%02lx\n", 1440 r, tf->tf_trapno, tf->tf_addr, tf->tf_rip, tf->tf_rsp, 1441 tf->tf_xflags, frame->if_xflags); 1442 #endif 1443 if (r < 0) { 1444 if (errno != EINTR) 1445 panic("vmspace_ctl failed error %d", errno); 1446 } else { 1447 if (tf->tf_trapno) { 1448 user_trap(tf); 1449 } 1450 } 1451 if (mycpu->gd_reqflags & RQF_AST_MASK) { 1452 tf->tf_trapno = T_ASTFLT; 1453 user_trap(tf); 1454 } 1455 tf->tf_trapno = 0; 1456 } 1457 } 1458 1459 /* 1460 * If PGEX_FPFAULT is set then set FP_VIRTFP in the PCB to force a T_DNA 1461 * fault (which is then passed back to the virtual kernel) if an attempt is 1462 * made to use the FP unit. 1463 * 1464 * XXX this is a fairly big hack. 1465 */ 1466 void 1467 set_vkernel_fp(struct trapframe *frame) 1468 { 1469 struct thread *td = curthread; 1470 1471 if (frame->tf_xflags & PGEX_FPFAULT) { 1472 td->td_pcb->pcb_flags |= FP_VIRTFP; 1473 if (mdcpu->gd_npxthread == td) 1474 npxexit(); 1475 } else { 1476 td->td_pcb->pcb_flags &= ~FP_VIRTFP; 1477 } 1478 } 1479 1480 /* 1481 * Called from vkernel_trap() to fixup the vkernel's syscall 1482 * frame for vmspace_ctl() return. 1483 */ 1484 void 1485 cpu_vkernel_trap(struct trapframe *frame, int error) 1486 { 1487 frame->tf_rax = error; 1488 if (error) 1489 frame->tf_rflags |= PSL_C; 1490 else 1491 frame->tf_rflags &= ~PSL_C; 1492 } 1493