| 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 | * 386 Trap and System call handling |
| 43 | */ |
| 44 | |
| 45 | #include "use_isa.h" |
| 46 | #include "use_npx.h" |
| 47 | |
| 48 | #include "opt_cpu.h" |
| 49 | #include "opt_ddb.h" |
| 50 | #include "opt_ktrace.h" |
| 51 | #include "opt_clock.h" |
| 52 | #include "opt_trap.h" |
| 53 | |
| 54 | #include <sys/param.h> |
| 55 | #include <sys/systm.h> |
| 56 | #include <sys/proc.h> |
| 57 | #include <sys/pioctl.h> |
| 58 | #include <sys/kernel.h> |
| 59 | #include <sys/kerneldump.h> |
| 60 | #include <sys/resourcevar.h> |
| 61 | #include <sys/signalvar.h> |
| 62 | #include <sys/signal2.h> |
| 63 | #include <sys/syscall.h> |
| 64 | #include <sys/sysctl.h> |
| 65 | #include <sys/sysent.h> |
| 66 | #include <sys/uio.h> |
| 67 | #include <sys/vmmeter.h> |
| 68 | #include <sys/malloc.h> |
| 69 | #ifdef KTRACE |
| 70 | #include <sys/ktrace.h> |
| 71 | #endif |
| 72 | #include <sys/ktr.h> |
| 73 | #include <sys/upcall.h> |
| 74 | #include <sys/vkernel.h> |
| 75 | #include <sys/sysproto.h> |
| 76 | #include <sys/sysunion.h> |
| 77 | |
| 78 | #include <vm/vm.h> |
| 79 | #include <vm/vm_param.h> |
| 80 | #include <sys/lock.h> |
| 81 | #include <vm/pmap.h> |
| 82 | #include <vm/vm_kern.h> |
| 83 | #include <vm/vm_map.h> |
| 84 | #include <vm/vm_page.h> |
| 85 | #include <vm/vm_extern.h> |
| 86 | |
| 87 | #include <machine/cpu.h> |
| 88 | #include <machine/md_var.h> |
| 89 | #include <machine/pcb.h> |
| 90 | #include <machine/smp.h> |
| 91 | #include <machine/tss.h> |
| 92 | #include <machine/specialreg.h> |
| 93 | #include <machine/globaldata.h> |
| 94 | #include <machine/intr_machdep.h> |
| 95 | |
| 96 | #include <machine_base/isa/isa_intr.h> |
| 97 | #include <machine_base/apic/lapic.h> |
| 98 | |
| 99 | #ifdef POWERFAIL_NMI |
| 100 | #include <sys/syslog.h> |
| 101 | #include <machine/clock.h> |
| 102 | #endif |
| 103 | |
| 104 | #include <machine/vm86.h> |
| 105 | |
| 106 | #include <ddb/ddb.h> |
| 107 | |
| 108 | #include <sys/msgport2.h> |
| 109 | #include <sys/thread2.h> |
| 110 | #include <sys/mplock2.h> |
| 111 | |
| 112 | #define MAKEMPSAFE(have_mplock) \ |
| 113 | if (have_mplock == 0) { \ |
| 114 | get_mplock(); \ |
| 115 | have_mplock = 1; \ |
| 116 | } |
| 117 | |
| 118 | int (*pmath_emulate) (struct trapframe *); |
| 119 | |
| 120 | extern void trap (struct trapframe *frame); |
| 121 | extern void syscall2 (struct trapframe *frame); |
| 122 | |
| 123 | static int trap_pfault (struct trapframe *, int, vm_offset_t); |
| 124 | static void trap_fatal (struct trapframe *, vm_offset_t); |
| 125 | void dblfault_handler (void); |
| 126 | |
| 127 | extern inthand_t IDTVEC(syscall); |
| 128 | |
| 129 | #define MAX_TRAP_MSG 28 |
| 130 | static char *trap_msg[] = { |
| 131 | "", /* 0 unused */ |
| 132 | "privileged instruction fault", /* 1 T_PRIVINFLT */ |
| 133 | "", /* 2 unused */ |
| 134 | "breakpoint instruction fault", /* 3 T_BPTFLT */ |
| 135 | "", /* 4 unused */ |
| 136 | "", /* 5 unused */ |
| 137 | "arithmetic trap", /* 6 T_ARITHTRAP */ |
| 138 | "system forced exception", /* 7 T_ASTFLT */ |
| 139 | "", /* 8 unused */ |
| 140 | "general protection fault", /* 9 T_PROTFLT */ |
| 141 | "trace trap", /* 10 T_TRCTRAP */ |
| 142 | "", /* 11 unused */ |
| 143 | "page fault", /* 12 T_PAGEFLT */ |
| 144 | "", /* 13 unused */ |
| 145 | "alignment fault", /* 14 T_ALIGNFLT */ |
| 146 | "", /* 15 unused */ |
| 147 | "", /* 16 unused */ |
| 148 | "", /* 17 unused */ |
| 149 | "integer divide fault", /* 18 T_DIVIDE */ |
| 150 | "non-maskable interrupt trap", /* 19 T_NMI */ |
| 151 | "overflow trap", /* 20 T_OFLOW */ |
| 152 | "FPU bounds check fault", /* 21 T_BOUND */ |
| 153 | "FPU device not available", /* 22 T_DNA */ |
| 154 | "double fault", /* 23 T_DOUBLEFLT */ |
| 155 | "FPU operand fetch fault", /* 24 T_FPOPFLT */ |
| 156 | "invalid TSS fault", /* 25 T_TSSFLT */ |
| 157 | "segment not present fault", /* 26 T_SEGNPFLT */ |
| 158 | "stack fault", /* 27 T_STKFLT */ |
| 159 | "machine check trap", /* 28 T_MCHK */ |
| 160 | }; |
| 161 | |
| 162 | #if defined(I586_CPU) && !defined(NO_F00F_HACK) |
| 163 | extern int has_f00f_bug; |
| 164 | #endif |
| 165 | |
| 166 | #ifdef DDB |
| 167 | static int ddb_on_nmi = 1; |
| 168 | SYSCTL_INT(_machdep, OID_AUTO, ddb_on_nmi, CTLFLAG_RW, |
| 169 | &ddb_on_nmi, 0, "Go to DDB on NMI"); |
| 170 | #endif |
| 171 | static int panic_on_nmi = 1; |
| 172 | SYSCTL_INT(_machdep, OID_AUTO, panic_on_nmi, CTLFLAG_RW, |
| 173 | &panic_on_nmi, 0, "Panic on NMI"); |
| 174 | static int fast_release; |
| 175 | SYSCTL_INT(_machdep, OID_AUTO, fast_release, CTLFLAG_RW, |
| 176 | &fast_release, 0, "Passive Release was optimal"); |
| 177 | static int slow_release; |
| 178 | SYSCTL_INT(_machdep, OID_AUTO, slow_release, CTLFLAG_RW, |
| 179 | &slow_release, 0, "Passive Release was nonoptimal"); |
| 180 | |
| 181 | MALLOC_DEFINE(M_SYSMSG, "sysmsg", "sysmsg structure"); |
| 182 | extern int max_sysmsg; |
| 183 | |
| 184 | /* |
| 185 | * Passively intercepts the thread switch function to increase the thread |
| 186 | * priority from a user priority to a kernel priority, reducing |
| 187 | * syscall and trap overhead for the case where no switch occurs. |
| 188 | * |
| 189 | * Synchronizes td_ucred with p_ucred. This is used by system calls, |
| 190 | * signal handling, faults, AST traps, and anything else that enters the |
| 191 | * kernel from userland and provides the kernel with a stable read-only |
| 192 | * copy of the process ucred. |
| 193 | */ |
| 194 | static __inline void |
| 195 | userenter(struct thread *curtd, struct proc *curp) |
| 196 | { |
| 197 | struct ucred *ocred; |
| 198 | struct ucred *ncred; |
| 199 | |
| 200 | curtd->td_release = lwkt_passive_release; |
| 201 | |
| 202 | if (curtd->td_ucred != curp->p_ucred) { |
| 203 | ncred = crhold(curp->p_ucred); |
| 204 | ocred = curtd->td_ucred; |
| 205 | curtd->td_ucred = ncred; |
| 206 | if (ocred) |
| 207 | crfree(ocred); |
| 208 | } |
| 209 | |
| 210 | } |
| 211 | |
| 212 | /* |
| 213 | * Handle signals, upcalls, profiling, and other AST's and/or tasks that |
| 214 | * must be completed before we can return to or try to return to userland. |
| 215 | * |
| 216 | * Note that td_sticks is a 64 bit quantity, but there's no point doing 64 |
| 217 | * arithmatic on the delta calculation so the absolute tick values are |
| 218 | * truncated to an integer. |
| 219 | */ |
| 220 | static void |
| 221 | userret(struct lwp *lp, struct trapframe *frame, int sticks) |
| 222 | { |
| 223 | struct proc *p = lp->lwp_proc; |
| 224 | void (*hook)(void); |
| 225 | int sig; |
| 226 | |
| 227 | if (p->p_userret != NULL) { |
| 228 | hook = p->p_userret; |
| 229 | p->p_userret = NULL; |
| 230 | (*hook)(); |
| 231 | } |
| 232 | |
| 233 | /* |
| 234 | * Charge system time if profiling. Note: times are in microseconds. |
| 235 | * This may do a copyout and block, so do it first even though it |
| 236 | * means some system time will be charged as user time. |
| 237 | */ |
| 238 | if (p->p_flags & P_PROFIL) { |
| 239 | addupc_task(p, frame->tf_eip, |
| 240 | (u_int)((int)lp->lwp_thread->td_sticks - sticks)); |
| 241 | } |
| 242 | |
| 243 | recheck: |
| 244 | /* |
| 245 | * If the jungle wants us dead, so be it. |
| 246 | */ |
| 247 | if (lp->lwp_mpflags & LWP_MP_WEXIT) { |
| 248 | lwkt_gettoken(&p->p_token); |
| 249 | lwp_exit(0); |
| 250 | lwkt_reltoken(&p->p_token); /* NOT REACHED */ |
| 251 | } |
| 252 | |
| 253 | /* |
| 254 | * Block here if we are in a stopped state. |
| 255 | */ |
| 256 | if (p->p_stat == SSTOP || dump_stop_usertds) { |
| 257 | lwkt_gettoken(&p->p_token); |
| 258 | tstop(); |
| 259 | lwkt_reltoken(&p->p_token); |
| 260 | goto recheck; |
| 261 | } |
| 262 | |
| 263 | /* |
| 264 | * Post any pending upcalls. If running a virtual kernel be sure |
| 265 | * to restore the virtual kernel's vmspace before posting the upcall. |
| 266 | */ |
| 267 | if (p->p_flags & (P_SIGVTALRM | P_SIGPROF | P_UPCALLPEND)) { |
| 268 | lwkt_gettoken(&p->p_token); |
| 269 | if (p->p_flags & P_SIGVTALRM) { |
| 270 | p->p_flags &= ~P_SIGVTALRM; |
| 271 | ksignal(p, SIGVTALRM); |
| 272 | } |
| 273 | if (p->p_flags & P_SIGPROF) { |
| 274 | p->p_flags &= ~P_SIGPROF; |
| 275 | ksignal(p, SIGPROF); |
| 276 | } |
| 277 | if (p->p_flags & P_UPCALLPEND) { |
| 278 | p->p_flags &= ~P_UPCALLPEND; |
| 279 | postupcall(lp); |
| 280 | } |
| 281 | lwkt_reltoken(&p->p_token); |
| 282 | goto recheck; |
| 283 | } |
| 284 | |
| 285 | /* |
| 286 | * Post any pending signals. If running a virtual kernel be sure |
| 287 | * to restore the virtual kernel's vmspace before posting the signal. |
| 288 | * |
| 289 | * WARNING! postsig() can exit and not return. |
| 290 | */ |
| 291 | if ((sig = CURSIG_TRACE(lp)) != 0) { |
| 292 | lwkt_gettoken(&p->p_token); |
| 293 | postsig(sig); |
| 294 | lwkt_reltoken(&p->p_token); |
| 295 | goto recheck; |
| 296 | } |
| 297 | |
| 298 | /* |
| 299 | * block here if we are swapped out, but still process signals |
| 300 | * (such as SIGKILL). proc0 (the swapin scheduler) is already |
| 301 | * aware of our situation, we do not have to wake it up. |
| 302 | */ |
| 303 | if (p->p_flags & P_SWAPPEDOUT) { |
| 304 | lwkt_gettoken(&p->p_token); |
| 305 | get_mplock(); |
| 306 | p->p_flags |= P_SWAPWAIT; |
| 307 | swapin_request(); |
| 308 | if (p->p_flags & P_SWAPWAIT) |
| 309 | tsleep(p, PCATCH, "SWOUT", 0); |
| 310 | p->p_flags &= ~P_SWAPWAIT; |
| 311 | rel_mplock(); |
| 312 | lwkt_reltoken(&p->p_token); |
| 313 | goto recheck; |
| 314 | } |
| 315 | |
| 316 | /* |
| 317 | * In a multi-threaded program it is possible for a thread to change |
| 318 | * signal state during a system call which temporarily changes the |
| 319 | * signal mask. In this case postsig() might not be run and we |
| 320 | * have to restore the mask ourselves. |
| 321 | */ |
| 322 | if (lp->lwp_flags & LWP_OLDMASK) { |
| 323 | lp->lwp_flags &= ~LWP_OLDMASK; |
| 324 | lp->lwp_sigmask = lp->lwp_oldsigmask; |
| 325 | goto recheck; |
| 326 | } |
| 327 | } |
| 328 | |
| 329 | /* |
| 330 | * Cleanup from userenter and any passive release that might have occured. |
| 331 | * We must reclaim the current-process designation before we can return |
| 332 | * to usermode. We also handle both LWKT and USER reschedule requests. |
| 333 | */ |
| 334 | static __inline void |
| 335 | userexit(struct lwp *lp) |
| 336 | { |
| 337 | struct thread *td = lp->lwp_thread; |
| 338 | /* globaldata_t gd = td->td_gd; */ |
| 339 | |
| 340 | /* |
| 341 | * Handle stop requests at kernel priority. Any requests queued |
| 342 | * after this loop will generate another AST. |
| 343 | */ |
| 344 | while (lp->lwp_proc->p_stat == SSTOP) { |
| 345 | lwkt_gettoken(&lp->lwp_proc->p_token); |
| 346 | tstop(); |
| 347 | lwkt_reltoken(&lp->lwp_proc->p_token); |
| 348 | } |
| 349 | |
| 350 | /* |
| 351 | * Become the current user scheduled process if we aren't already, |
| 352 | * and deal with reschedule requests and other factors. |
| 353 | */ |
| 354 | lp->lwp_proc->p_usched->acquire_curproc(lp); |
| 355 | /* WARNING: we may have migrated cpu's */ |
| 356 | /* gd = td->td_gd; */ |
| 357 | |
| 358 | /* |
| 359 | * Reduce our priority in preparation for a return to userland. If |
| 360 | * our passive release function was still in place, our priority was |
| 361 | * never raised and does not need to be reduced. |
| 362 | */ |
| 363 | lwkt_passive_recover(td); |
| 364 | } |
| 365 | |
| 366 | #if !defined(KTR_KERNENTRY) |
| 367 | #define KTR_KERNENTRY KTR_ALL |
| 368 | #endif |
| 369 | KTR_INFO_MASTER(kernentry); |
| 370 | KTR_INFO(KTR_KERNENTRY, kernentry, trap, 0, |
| 371 | "TRAP(pid %d, tid %d, trapno %d, eva %lu)", |
| 372 | pid_t pid, lwpid_t tid, register_t trapno, vm_offset_t eva); |
| 373 | KTR_INFO(KTR_KERNENTRY, kernentry, trap_ret, 0, "TRAP_RET(pid %d, tid %d)", |
| 374 | pid_t pid, lwpid_t tid); |
| 375 | KTR_INFO(KTR_KERNENTRY, kernentry, syscall, 0, "SYSC(pid %d, tid %d, nr %d)", |
| 376 | pid_t pid, lwpid_t tid, register_t trapno); |
| 377 | KTR_INFO(KTR_KERNENTRY, kernentry, syscall_ret, 0, "SYSRET(pid %d, tid %d, err %d)", |
| 378 | pid_t pid, lwpid_t tid, int err); |
| 379 | KTR_INFO(KTR_KERNENTRY, kernentry, fork_ret, 0, "FORKRET(pid %d, tid %d)", |
| 380 | pid_t pid, lwpid_t tid); |
| 381 | |
| 382 | /* |
| 383 | * Exception, fault, and trap interface to the kernel. |
| 384 | * This common code is called from assembly language IDT gate entry |
| 385 | * routines that prepare a suitable stack frame, and restore this |
| 386 | * frame after the exception has been processed. |
| 387 | * |
| 388 | * This function is also called from doreti in an interlock to handle ASTs. |
| 389 | * For example: hardwareint->INTROUTINE->(set ast)->doreti->trap |
| 390 | * |
| 391 | * NOTE! We have to retrieve the fault address prior to obtaining the |
| 392 | * MP lock because get_mplock() may switch out. YYY cr2 really ought |
| 393 | * to be retrieved by the assembly code, not here. |
| 394 | * |
| 395 | * XXX gd_trap_nesting_level currently prevents lwkt_switch() from panicing |
| 396 | * if an attempt is made to switch from a fast interrupt or IPI. This is |
| 397 | * necessary to properly take fatal kernel traps on SMP machines if |
| 398 | * get_mplock() has to block. |
| 399 | */ |
| 400 | |
| 401 | void |
| 402 | trap(struct trapframe *frame) |
| 403 | { |
| 404 | struct globaldata *gd = mycpu; |
| 405 | struct thread *td = gd->gd_curthread; |
| 406 | struct lwp *lp = td->td_lwp; |
| 407 | struct proc *p; |
| 408 | int sticks = 0; |
| 409 | int i = 0, ucode = 0, type, code; |
| 410 | int have_mplock = 0; |
| 411 | #ifdef INVARIANTS |
| 412 | int crit_count = td->td_critcount; |
| 413 | lwkt_tokref_t curstop = td->td_toks_stop; |
| 414 | #endif |
| 415 | vm_offset_t eva; |
| 416 | |
| 417 | p = td->td_proc; |
| 418 | #ifdef DDB |
| 419 | /* |
| 420 | * We need to allow T_DNA faults when the debugger is active since |
| 421 | * some dumping paths do large bcopy() which use the floating |
| 422 | * point registers for faster copying. |
| 423 | */ |
| 424 | if (db_active && frame->tf_trapno != T_DNA) { |
| 425 | eva = (frame->tf_trapno == T_PAGEFLT ? rcr2() : 0); |
| 426 | ++gd->gd_trap_nesting_level; |
| 427 | MAKEMPSAFE(have_mplock); |
| 428 | trap_fatal(frame, eva); |
| 429 | --gd->gd_trap_nesting_level; |
| 430 | goto out2; |
| 431 | } |
| 432 | #endif |
| 433 | |
| 434 | eva = 0; |
| 435 | ++gd->gd_trap_nesting_level; |
| 436 | if (frame->tf_trapno == T_PAGEFLT) { |
| 437 | /* |
| 438 | * For some Cyrix CPUs, %cr2 is clobbered by interrupts. |
| 439 | * This problem is worked around by using an interrupt |
| 440 | * gate for the pagefault handler. We are finally ready |
| 441 | * to read %cr2 and then must reenable interrupts. |
| 442 | * |
| 443 | * XXX this should be in the switch statement, but the |
| 444 | * NO_FOOF_HACK and VM86 goto and ifdefs obfuscate the |
| 445 | * flow of control too much for this to be obviously |
| 446 | * correct. |
| 447 | */ |
| 448 | eva = rcr2(); |
| 449 | cpu_enable_intr(); |
| 450 | } |
| 451 | |
| 452 | --gd->gd_trap_nesting_level; |
| 453 | |
| 454 | if (!(frame->tf_eflags & PSL_I)) { |
| 455 | /* |
| 456 | * Buggy application or kernel code has disabled interrupts |
| 457 | * and then trapped. Enabling interrupts now is wrong, but |
| 458 | * it is better than running with interrupts disabled until |
| 459 | * they are accidentally enabled later. |
| 460 | */ |
| 461 | type = frame->tf_trapno; |
| 462 | if (ISPL(frame->tf_cs)==SEL_UPL || (frame->tf_eflags & PSL_VM)) { |
| 463 | MAKEMPSAFE(have_mplock); |
| 464 | kprintf( |
| 465 | "pid %ld (%s): trap %d with interrupts disabled\n", |
| 466 | (long)curproc->p_pid, curproc->p_comm, type); |
| 467 | } else if (type != T_BPTFLT && type != T_TRCTRAP) { |
| 468 | /* |
| 469 | * XXX not quite right, since this may be for a |
| 470 | * multiple fault in user mode. |
| 471 | */ |
| 472 | MAKEMPSAFE(have_mplock); |
| 473 | kprintf("kernel trap %d with interrupts disabled\n", |
| 474 | type); |
| 475 | } |
| 476 | cpu_enable_intr(); |
| 477 | } |
| 478 | |
| 479 | #if defined(I586_CPU) && !defined(NO_F00F_HACK) |
| 480 | restart: |
| 481 | #endif |
| 482 | type = frame->tf_trapno; |
| 483 | code = frame->tf_err; |
| 484 | |
| 485 | if (in_vm86call) { |
| 486 | if (frame->tf_eflags & PSL_VM && |
| 487 | (type == T_PROTFLT || type == T_STKFLT)) { |
| 488 | KKASSERT(get_mplock_count(curthread) > 0); |
| 489 | i = vm86_emulate((struct vm86frame *)frame); |
| 490 | KKASSERT(get_mplock_count(curthread) > 0); |
| 491 | if (i != 0) { |
| 492 | /* |
| 493 | * returns to original process |
| 494 | */ |
| 495 | vm86_trap((struct vm86frame *)frame, |
| 496 | have_mplock); |
| 497 | KKASSERT(0); /* NOT REACHED */ |
| 498 | } |
| 499 | goto out2; |
| 500 | } |
| 501 | switch (type) { |
| 502 | /* |
| 503 | * these traps want either a process context, or |
| 504 | * assume a normal userspace trap. |
| 505 | */ |
| 506 | case T_PROTFLT: |
| 507 | case T_SEGNPFLT: |
| 508 | trap_fatal(frame, eva); |
| 509 | goto out2; |
| 510 | case T_TRCTRAP: |
| 511 | type = T_BPTFLT; /* kernel breakpoint */ |
| 512 | /* FALL THROUGH */ |
| 513 | } |
| 514 | goto kernel_trap; /* normal kernel trap handling */ |
| 515 | } |
| 516 | |
| 517 | if ((ISPL(frame->tf_cs) == SEL_UPL) || (frame->tf_eflags & PSL_VM)) { |
| 518 | /* user trap */ |
| 519 | |
| 520 | KTR_LOG(kernentry_trap, p->p_pid, lp->lwp_tid, |
| 521 | frame->tf_trapno, eva); |
| 522 | |
| 523 | userenter(td, p); |
| 524 | |
| 525 | sticks = (int)td->td_sticks; |
| 526 | lp->lwp_md.md_regs = frame; |
| 527 | |
| 528 | switch (type) { |
| 529 | case T_PRIVINFLT: /* privileged instruction fault */ |
| 530 | i = SIGILL; |
| 531 | ucode = ILL_PRVOPC; |
| 532 | break; |
| 533 | |
| 534 | case T_BPTFLT: /* bpt instruction fault */ |
| 535 | case T_TRCTRAP: /* trace trap */ |
| 536 | frame->tf_eflags &= ~PSL_T; |
| 537 | i = SIGTRAP; |
| 538 | ucode = (type == T_TRCTRAP ? TRAP_TRACE : TRAP_BRKPT); |
| 539 | break; |
| 540 | |
| 541 | case T_ARITHTRAP: /* arithmetic trap */ |
| 542 | ucode = code; |
| 543 | i = SIGFPE; |
| 544 | break; |
| 545 | |
| 546 | case T_ASTFLT: /* Allow process switch */ |
| 547 | mycpu->gd_cnt.v_soft++; |
| 548 | if (mycpu->gd_reqflags & RQF_AST_OWEUPC) { |
| 549 | atomic_clear_int(&mycpu->gd_reqflags, |
| 550 | RQF_AST_OWEUPC); |
| 551 | addupc_task(p, p->p_prof.pr_addr, |
| 552 | p->p_prof.pr_ticks); |
| 553 | } |
| 554 | goto out; |
| 555 | |
| 556 | /* |
| 557 | * The following two traps can happen in |
| 558 | * vm86 mode, and, if so, we want to handle |
| 559 | * them specially. |
| 560 | */ |
| 561 | case T_PROTFLT: /* general protection fault */ |
| 562 | case T_STKFLT: /* stack fault */ |
| 563 | if (frame->tf_eflags & PSL_VM) { |
| 564 | i = vm86_emulate((struct vm86frame *)frame); |
| 565 | if (i == 0) |
| 566 | goto out; |
| 567 | break; |
| 568 | } |
| 569 | i = SIGBUS; |
| 570 | ucode = (type == T_PROTFLT) ? BUS_OBJERR : BUS_ADRERR; |
| 571 | break; |
| 572 | case T_SEGNPFLT: /* segment not present fault */ |
| 573 | i = SIGBUS; |
| 574 | ucode = BUS_ADRERR; |
| 575 | break; |
| 576 | case T_TSSFLT: /* invalid TSS fault */ |
| 577 | case T_DOUBLEFLT: /* double fault */ |
| 578 | default: |
| 579 | i = SIGBUS; |
| 580 | ucode = BUS_OBJERR; |
| 581 | break; |
| 582 | |
| 583 | case T_PAGEFLT: /* page fault */ |
| 584 | i = trap_pfault(frame, TRUE, eva); |
| 585 | if (i == -1) |
| 586 | goto out; |
| 587 | #if defined(I586_CPU) && !defined(NO_F00F_HACK) |
| 588 | if (i == -2) |
| 589 | goto restart; |
| 590 | #endif |
| 591 | if (i == 0) |
| 592 | goto out; |
| 593 | |
| 594 | if (i == SIGSEGV) |
| 595 | ucode = SEGV_MAPERR; |
| 596 | else { |
| 597 | i = SIGSEGV; |
| 598 | ucode = SEGV_ACCERR; |
| 599 | } |
| 600 | break; |
| 601 | |
| 602 | case T_DIVIDE: /* integer divide fault */ |
| 603 | ucode = FPE_INTDIV; |
| 604 | i = SIGFPE; |
| 605 | break; |
| 606 | |
| 607 | #if NISA > 0 |
| 608 | case T_NMI: |
| 609 | MAKEMPSAFE(have_mplock); |
| 610 | #ifdef POWERFAIL_NMI |
| 611 | goto handle_powerfail; |
| 612 | #else /* !POWERFAIL_NMI */ |
| 613 | /* machine/parity/power fail/"kitchen sink" faults */ |
| 614 | if (isa_nmi(code) == 0) { |
| 615 | #ifdef DDB |
| 616 | /* |
| 617 | * NMI can be hooked up to a pushbutton |
| 618 | * for debugging. |
| 619 | */ |
| 620 | if (ddb_on_nmi) { |
| 621 | kprintf ("NMI ... going to debugger\n"); |
| 622 | kdb_trap (type, 0, frame); |
| 623 | } |
| 624 | #endif /* DDB */ |
| 625 | goto out2; |
| 626 | } else if (panic_on_nmi) |
| 627 | panic("NMI indicates hardware failure"); |
| 628 | break; |
| 629 | #endif /* POWERFAIL_NMI */ |
| 630 | #endif /* NISA > 0 */ |
| 631 | |
| 632 | case T_OFLOW: /* integer overflow fault */ |
| 633 | ucode = FPE_INTOVF; |
| 634 | i = SIGFPE; |
| 635 | break; |
| 636 | |
| 637 | case T_BOUND: /* bounds check fault */ |
| 638 | ucode = FPE_FLTSUB; |
| 639 | i = SIGFPE; |
| 640 | break; |
| 641 | |
| 642 | case T_DNA: |
| 643 | /* |
| 644 | * Virtual kernel intercept - pass the DNA exception |
| 645 | * to the virtual kernel if it asked to handle it. |
| 646 | * This occurs when the virtual kernel is holding |
| 647 | * onto the FP context for a different emulated |
| 648 | * process then the one currently running. |
| 649 | * |
| 650 | * We must still call npxdna() since we may have |
| 651 | * saved FP state that the virtual kernel needs |
| 652 | * to hand over to a different emulated process. |
| 653 | */ |
| 654 | if (lp->lwp_vkernel && lp->lwp_vkernel->ve && |
| 655 | (td->td_pcb->pcb_flags & FP_VIRTFP) |
| 656 | ) { |
| 657 | npxdna(); |
| 658 | break; |
| 659 | } |
| 660 | |
| 661 | #if NNPX > 0 |
| 662 | /* |
| 663 | * The kernel may have switched out the FP unit's |
| 664 | * state, causing the user process to take a fault |
| 665 | * when it tries to use the FP unit. Restore the |
| 666 | * state here |
| 667 | */ |
| 668 | if (npxdna()) |
| 669 | goto out; |
| 670 | #endif |
| 671 | if (!pmath_emulate) { |
| 672 | i = SIGFPE; |
| 673 | ucode = FPE_FPU_NP_TRAP; |
| 674 | break; |
| 675 | } |
| 676 | i = (*pmath_emulate)(frame); |
| 677 | if (i == 0) { |
| 678 | if (!(frame->tf_eflags & PSL_T)) |
| 679 | goto out2; |
| 680 | frame->tf_eflags &= ~PSL_T; |
| 681 | i = SIGTRAP; |
| 682 | } |
| 683 | /* else ucode = emulator_only_knows() XXX */ |
| 684 | break; |
| 685 | |
| 686 | case T_FPOPFLT: /* FPU operand fetch fault */ |
| 687 | ucode = ILL_COPROC; |
| 688 | i = SIGILL; |
| 689 | break; |
| 690 | |
| 691 | case T_XMMFLT: /* SIMD floating-point exception */ |
| 692 | ucode = 0; /* XXX */ |
| 693 | i = SIGFPE; |
| 694 | break; |
| 695 | } |
| 696 | } else { |
| 697 | kernel_trap: |
| 698 | /* kernel trap */ |
| 699 | |
| 700 | switch (type) { |
| 701 | case T_PAGEFLT: /* page fault */ |
| 702 | trap_pfault(frame, FALSE, eva); |
| 703 | goto out2; |
| 704 | |
| 705 | case T_DNA: |
| 706 | #if NNPX > 0 |
| 707 | /* |
| 708 | * The kernel may be using npx for copying or other |
| 709 | * purposes. |
| 710 | */ |
| 711 | if (npxdna()) |
| 712 | goto out2; |
| 713 | #endif |
| 714 | break; |
| 715 | |
| 716 | case T_PROTFLT: /* general protection fault */ |
| 717 | case T_SEGNPFLT: /* segment not present fault */ |
| 718 | /* |
| 719 | * Invalid segment selectors and out of bounds |
| 720 | * %eip's and %esp's can be set up in user mode. |
| 721 | * This causes a fault in kernel mode when the |
| 722 | * kernel tries to return to user mode. We want |
| 723 | * to get this fault so that we can fix the |
| 724 | * problem here and not have to check all the |
| 725 | * selectors and pointers when the user changes |
| 726 | * them. |
| 727 | */ |
| 728 | #define MAYBE_DORETI_FAULT(where, whereto) \ |
| 729 | do { \ |
| 730 | if (frame->tf_eip == (int)where) { \ |
| 731 | frame->tf_eip = (int)whereto; \ |
| 732 | goto out2; \ |
| 733 | } \ |
| 734 | } while (0) |
| 735 | if (mycpu->gd_intr_nesting_level == 0) { |
| 736 | /* |
| 737 | * Invalid %fs's and %gs's can be created using |
| 738 | * procfs or PT_SETREGS or by invalidating the |
| 739 | * underlying LDT entry. This causes a fault |
| 740 | * in kernel mode when the kernel attempts to |
| 741 | * switch contexts. Lose the bad context |
| 742 | * (XXX) so that we can continue, and generate |
| 743 | * a signal. |
| 744 | */ |
| 745 | MAYBE_DORETI_FAULT(doreti_iret, |
| 746 | doreti_iret_fault); |
| 747 | MAYBE_DORETI_FAULT(doreti_popl_ds, |
| 748 | doreti_popl_ds_fault); |
| 749 | MAYBE_DORETI_FAULT(doreti_popl_es, |
| 750 | doreti_popl_es_fault); |
| 751 | MAYBE_DORETI_FAULT(doreti_popl_fs, |
| 752 | doreti_popl_fs_fault); |
| 753 | MAYBE_DORETI_FAULT(doreti_popl_gs, |
| 754 | doreti_popl_gs_fault); |
| 755 | |
| 756 | /* |
| 757 | * NOTE: cpu doesn't push esp on kernel trap |
| 758 | */ |
| 759 | if (td->td_pcb->pcb_onfault && |
| 760 | td->td_pcb->pcb_onfault_sp == |
| 761 | (int)&frame->tf_esp) { |
| 762 | frame->tf_eip = |
| 763 | (register_t)td->td_pcb->pcb_onfault; |
| 764 | goto out2; |
| 765 | } |
| 766 | } |
| 767 | break; |
| 768 | |
| 769 | case T_TSSFLT: |
| 770 | /* |
| 771 | * PSL_NT can be set in user mode and isn't cleared |
| 772 | * automatically when the kernel is entered. This |
| 773 | * causes a TSS fault when the kernel attempts to |
| 774 | * `iret' because the TSS link is uninitialized. We |
| 775 | * want to get this fault so that we can fix the |
| 776 | * problem here and not every time the kernel is |
| 777 | * entered. |
| 778 | */ |
| 779 | if (frame->tf_eflags & PSL_NT) { |
| 780 | frame->tf_eflags &= ~PSL_NT; |
| 781 | goto out2; |
| 782 | } |
| 783 | break; |
| 784 | |
| 785 | case T_TRCTRAP: /* trace trap */ |
| 786 | if (frame->tf_eip == (int)IDTVEC(syscall)) { |
| 787 | /* |
| 788 | * We've just entered system mode via the |
| 789 | * syscall lcall. Continue single stepping |
| 790 | * silently until the syscall handler has |
| 791 | * saved the flags. |
| 792 | */ |
| 793 | goto out2; |
| 794 | } |
| 795 | if (frame->tf_eip == (int)IDTVEC(syscall) + 1) { |
| 796 | /* |
| 797 | * The syscall handler has now saved the |
| 798 | * flags. Stop single stepping it. |
| 799 | */ |
| 800 | frame->tf_eflags &= ~PSL_T; |
| 801 | goto out2; |
| 802 | } |
| 803 | /* |
| 804 | * Ignore debug register trace traps due to |
| 805 | * accesses in the user's address space, which |
| 806 | * can happen under several conditions such as |
| 807 | * if a user sets a watchpoint on a buffer and |
| 808 | * then passes that buffer to a system call. |
| 809 | * We still want to get TRCTRAPS for addresses |
| 810 | * in kernel space because that is useful when |
| 811 | * debugging the kernel. |
| 812 | */ |
| 813 | if (user_dbreg_trap()) { |
| 814 | /* |
| 815 | * Reset breakpoint bits because the |
| 816 | * processor doesn't |
| 817 | */ |
| 818 | load_dr6(rdr6() & 0xfffffff0); |
| 819 | goto out2; |
| 820 | } |
| 821 | /* |
| 822 | * FALLTHROUGH (TRCTRAP kernel mode, kernel address) |
| 823 | */ |
| 824 | case T_BPTFLT: |
| 825 | /* |
| 826 | * If DDB is enabled, let it handle the debugger trap. |
| 827 | * Otherwise, debugger traps "can't happen". |
| 828 | */ |
| 829 | ucode = TRAP_BRKPT; |
| 830 | #ifdef DDB |
| 831 | MAKEMPSAFE(have_mplock); |
| 832 | if (kdb_trap (type, 0, frame)) |
| 833 | goto out2; |
| 834 | #endif |
| 835 | break; |
| 836 | |
| 837 | #if NISA > 0 |
| 838 | case T_NMI: |
| 839 | MAKEMPSAFE(have_mplock); |
| 840 | #ifdef POWERFAIL_NMI |
| 841 | #ifndef TIMER_FREQ |
| 842 | # define TIMER_FREQ 1193182 |
| 843 | #endif |
| 844 | handle_powerfail: |
| 845 | { |
| 846 | static unsigned lastalert = 0; |
| 847 | |
| 848 | if(time_second - lastalert > 10) |
| 849 | { |
| 850 | log(LOG_WARNING, "NMI: power fail\n"); |
| 851 | sysbeep(TIMER_FREQ/880, hz); |
| 852 | lastalert = time_second; |
| 853 | } |
| 854 | /* YYY mp count */ |
| 855 | goto out2; |
| 856 | } |
| 857 | #else /* !POWERFAIL_NMI */ |
| 858 | /* machine/parity/power fail/"kitchen sink" faults */ |
| 859 | if (isa_nmi(code) == 0) { |
| 860 | #ifdef DDB |
| 861 | /* |
| 862 | * NMI can be hooked up to a pushbutton |
| 863 | * for debugging. |
| 864 | */ |
| 865 | if (ddb_on_nmi) { |
| 866 | kprintf ("NMI ... going to debugger\n"); |
| 867 | kdb_trap (type, 0, frame); |
| 868 | } |
| 869 | #endif /* DDB */ |
| 870 | goto out2; |
| 871 | } else if (panic_on_nmi == 0) |
| 872 | goto out2; |
| 873 | /* FALL THROUGH */ |
| 874 | #endif /* POWERFAIL_NMI */ |
| 875 | #endif /* NISA > 0 */ |
| 876 | } |
| 877 | |
| 878 | MAKEMPSAFE(have_mplock); |
| 879 | trap_fatal(frame, eva); |
| 880 | goto out2; |
| 881 | } |
| 882 | |
| 883 | /* |
| 884 | * Virtual kernel intercept - if the fault is directly related to a |
| 885 | * VM context managed by a virtual kernel then let the virtual kernel |
| 886 | * handle it. |
| 887 | */ |
| 888 | if (lp->lwp_vkernel && lp->lwp_vkernel->ve) { |
| 889 | vkernel_trap(lp, frame); |
| 890 | goto out; |
| 891 | } |
| 892 | |
| 893 | /* Translate fault for emulators (e.g. Linux) */ |
| 894 | if (*p->p_sysent->sv_transtrap) |
| 895 | i = (*p->p_sysent->sv_transtrap)(i, type); |
| 896 | |
| 897 | MAKEMPSAFE(have_mplock); |
| 898 | trapsignal(lp, i, ucode); |
| 899 | |
| 900 | #ifdef DEBUG |
| 901 | if (type <= MAX_TRAP_MSG) { |
| 902 | uprintf("fatal process exception: %s", |
| 903 | trap_msg[type]); |
| 904 | if ((type == T_PAGEFLT) || (type == T_PROTFLT)) |
| 905 | uprintf(", fault VA = 0x%lx", (u_long)eva); |
| 906 | uprintf("\n"); |
| 907 | } |
| 908 | #endif |
| 909 | |
| 910 | out: |
| 911 | userret(lp, frame, sticks); |
| 912 | userexit(lp); |
| 913 | out2: ; |
| 914 | if (have_mplock) |
| 915 | rel_mplock(); |
| 916 | if (p != NULL && lp != NULL) |
| 917 | KTR_LOG(kernentry_trap_ret, p->p_pid, lp->lwp_tid); |
| 918 | #ifdef INVARIANTS |
| 919 | KASSERT(crit_count == td->td_critcount, |
| 920 | ("trap: critical section count mismatch! %d/%d", |
| 921 | crit_count, td->td_pri)); |
| 922 | KASSERT(curstop == td->td_toks_stop, |
| 923 | ("trap: extra tokens held after trap! %zd/%zd", |
| 924 | curstop - &td->td_toks_base, |
| 925 | td->td_toks_stop - &td->td_toks_base)); |
| 926 | #endif |
| 927 | } |
| 928 | |
| 929 | int |
| 930 | trap_pfault(struct trapframe *frame, int usermode, vm_offset_t eva) |
| 931 | { |
| 932 | vm_offset_t va; |
| 933 | struct vmspace *vm = NULL; |
| 934 | vm_map_t map = 0; |
| 935 | int rv = 0; |
| 936 | int fault_flags; |
| 937 | vm_prot_t ftype; |
| 938 | thread_t td = curthread; |
| 939 | struct lwp *lp = td->td_lwp; |
| 940 | |
| 941 | va = trunc_page(eva); |
| 942 | if (va >= KERNBASE) { |
| 943 | /* |
| 944 | * Don't allow user-mode faults in kernel address space. |
| 945 | * An exception: if the faulting address is the invalid |
| 946 | * instruction entry in the IDT, then the Intel Pentium |
| 947 | * F00F bug workaround was triggered, and we need to |
| 948 | * treat it is as an illegal instruction, and not a page |
| 949 | * fault. |
| 950 | */ |
| 951 | #if defined(I586_CPU) && !defined(NO_F00F_HACK) |
| 952 | if ((eva == (unsigned int)&idt[6]) && has_f00f_bug) { |
| 953 | frame->tf_trapno = T_PRIVINFLT; |
| 954 | return -2; |
| 955 | } |
| 956 | #endif |
| 957 | if (usermode) |
| 958 | goto nogo; |
| 959 | |
| 960 | map = &kernel_map; |
| 961 | } else { |
| 962 | /* |
| 963 | * This is a fault on non-kernel virtual memory. |
| 964 | * vm is initialized above to NULL. If curproc is NULL |
| 965 | * or curproc->p_vmspace is NULL the fault is fatal. |
| 966 | */ |
| 967 | if (lp != NULL) |
| 968 | vm = lp->lwp_vmspace; |
| 969 | |
| 970 | if (vm == NULL) |
| 971 | goto nogo; |
| 972 | |
| 973 | map = &vm->vm_map; |
| 974 | } |
| 975 | |
| 976 | if (frame->tf_err & PGEX_W) |
| 977 | ftype = VM_PROT_WRITE; |
| 978 | else |
| 979 | ftype = VM_PROT_READ; |
| 980 | |
| 981 | if (map != &kernel_map) { |
| 982 | /* |
| 983 | * Keep swapout from messing with us during this |
| 984 | * critical time. |
| 985 | */ |
| 986 | PHOLD(lp->lwp_proc); |
| 987 | |
| 988 | /* |
| 989 | * Issue fault |
| 990 | */ |
| 991 | fault_flags = 0; |
| 992 | if (usermode) |
| 993 | fault_flags |= VM_FAULT_BURST; |
| 994 | if (ftype & VM_PROT_WRITE) |
| 995 | fault_flags |= VM_FAULT_DIRTY; |
| 996 | else |
| 997 | fault_flags |= VM_FAULT_NORMAL; |
| 998 | rv = vm_fault(map, va, ftype, fault_flags); |
| 999 | PRELE(lp->lwp_proc); |
| 1000 | } else { |
| 1001 | /* |
| 1002 | * Don't have to worry about process locking or stacks in the |
| 1003 | * kernel. |
| 1004 | */ |
| 1005 | rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL); |
| 1006 | } |
| 1007 | if (rv == KERN_SUCCESS) |
| 1008 | return (0); |
| 1009 | nogo: |
| 1010 | if (!usermode) { |
| 1011 | /* |
| 1012 | * NOTE: cpu doesn't push esp on kernel trap |
| 1013 | */ |
| 1014 | if (td->td_gd->gd_intr_nesting_level == 0 && |
| 1015 | td->td_pcb->pcb_onfault && |
| 1016 | td->td_pcb->pcb_onfault_sp == (int)&frame->tf_esp) { |
| 1017 | frame->tf_eip = (register_t)td->td_pcb->pcb_onfault; |
| 1018 | return (0); |
| 1019 | } |
| 1020 | if (td->td_gd->gd_intr_nesting_level == 0 && |
| 1021 | td->td_pcb->pcb_onfault) { |
| 1022 | kprintf("ESP mismatch %p %08x\n", |
| 1023 | &frame->tf_esp, td->td_pcb->pcb_onfault_sp); |
| 1024 | } |
| 1025 | trap_fatal(frame, eva); |
| 1026 | return (-1); |
| 1027 | } |
| 1028 | |
| 1029 | /* kludge to pass faulting virtual address to sendsig */ |
| 1030 | frame->tf_xflags = frame->tf_err; |
| 1031 | frame->tf_err = eva; |
| 1032 | |
| 1033 | return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV); |
| 1034 | } |
| 1035 | |
| 1036 | static void |
| 1037 | trap_fatal(struct trapframe *frame, vm_offset_t eva) |
| 1038 | { |
| 1039 | int code, type, ss, esp; |
| 1040 | struct soft_segment_descriptor softseg; |
| 1041 | |
| 1042 | code = frame->tf_err; |
| 1043 | type = frame->tf_trapno; |
| 1044 | sdtossd(&gdt[mycpu->gd_cpuid * NGDT + IDXSEL(frame->tf_cs & 0xffff)].sd, &softseg); |
| 1045 | |
| 1046 | if (type <= MAX_TRAP_MSG) |
| 1047 | kprintf("\n\nFatal trap %d: %s while in %s mode\n", |
| 1048 | type, trap_msg[type], |
| 1049 | frame->tf_eflags & PSL_VM ? "vm86" : |
| 1050 | ISPL(frame->tf_cs) == SEL_UPL ? "user" : "kernel"); |
| 1051 | /* three separate prints in case of a trap on an unmapped page */ |
| 1052 | kprintf("cpuid = %d; ", mycpu->gd_cpuid); |
| 1053 | kprintf("lapic.id = %08x\n", lapic->id); |
| 1054 | if (type == T_PAGEFLT) { |
| 1055 | kprintf("fault virtual address = %p\n", (void *)eva); |
| 1056 | kprintf("fault code = %s %s, %s\n", |
| 1057 | code & PGEX_U ? "user" : "supervisor", |
| 1058 | code & PGEX_W ? "write" : "read", |
| 1059 | code & PGEX_P ? "protection violation" : "page not present"); |
| 1060 | } |
| 1061 | kprintf("instruction pointer = 0x%x:0x%x\n", |
| 1062 | frame->tf_cs & 0xffff, frame->tf_eip); |
| 1063 | if ((ISPL(frame->tf_cs) == SEL_UPL) || (frame->tf_eflags & PSL_VM)) { |
| 1064 | ss = frame->tf_ss & 0xffff; |
| 1065 | esp = frame->tf_esp; |
| 1066 | } else { |
| 1067 | ss = GSEL(GDATA_SEL, SEL_KPL); |
| 1068 | esp = (int)&frame->tf_esp; |
| 1069 | } |
| 1070 | kprintf("stack pointer = 0x%x:0x%x\n", ss, esp); |
| 1071 | kprintf("frame pointer = 0x%x:0x%x\n", ss, frame->tf_ebp); |
| 1072 | kprintf("code segment = base 0x%x, limit 0x%x, type 0x%x\n", |
| 1073 | softseg.ssd_base, softseg.ssd_limit, softseg.ssd_type); |
| 1074 | kprintf(" = DPL %d, pres %d, def32 %d, gran %d\n", |
| 1075 | softseg.ssd_dpl, softseg.ssd_p, softseg.ssd_def32, |
| 1076 | softseg.ssd_gran); |
| 1077 | kprintf("processor eflags = "); |
| 1078 | if (frame->tf_eflags & PSL_T) |
| 1079 | kprintf("trace trap, "); |
| 1080 | if (frame->tf_eflags & PSL_I) |
| 1081 | kprintf("interrupt enabled, "); |
| 1082 | if (frame->tf_eflags & PSL_NT) |
| 1083 | kprintf("nested task, "); |
| 1084 | if (frame->tf_eflags & PSL_RF) |
| 1085 | kprintf("resume, "); |
| 1086 | if (frame->tf_eflags & PSL_VM) |
| 1087 | kprintf("vm86, "); |
| 1088 | kprintf("IOPL = %d\n", (frame->tf_eflags & PSL_IOPL) >> 12); |
| 1089 | kprintf("current process = "); |
| 1090 | if (curproc) { |
| 1091 | kprintf("%lu (%s)\n", |
| 1092 | (u_long)curproc->p_pid, curproc->p_comm ? |
| 1093 | curproc->p_comm : ""); |
| 1094 | } else { |
| 1095 | kprintf("Idle\n"); |
| 1096 | } |
| 1097 | kprintf("current thread = pri %d ", curthread->td_pri); |
| 1098 | if (curthread->td_critcount) |
| 1099 | kprintf("(CRIT)"); |
| 1100 | kprintf("\n"); |
| 1101 | /** |
| 1102 | * XXX FIXME: |
| 1103 | * we probably SHOULD have stopped the other CPUs before now! |
| 1104 | * another CPU COULD have been touching cpl at this moment... |
| 1105 | */ |
| 1106 | kprintf(" <- SMP: XXX"); |
| 1107 | kprintf("\n"); |
| 1108 | |
| 1109 | #ifdef KDB |
| 1110 | if (kdb_trap(&psl)) |
| 1111 | return; |
| 1112 | #endif |
| 1113 | #ifdef DDB |
| 1114 | if ((debugger_on_panic || db_active) && kdb_trap(type, code, frame)) |
| 1115 | return; |
| 1116 | #endif |
| 1117 | kprintf("trap number = %d\n", type); |
| 1118 | if (type <= MAX_TRAP_MSG) |
| 1119 | panic("%s", trap_msg[type]); |
| 1120 | else |
| 1121 | panic("unknown/reserved trap"); |
| 1122 | } |
| 1123 | |
| 1124 | /* |
| 1125 | * Double fault handler. Called when a fault occurs while writing |
| 1126 | * a frame for a trap/exception onto the stack. This usually occurs |
| 1127 | * when the stack overflows (such is the case with infinite recursion, |
| 1128 | * for example). |
| 1129 | * |
| 1130 | * XXX Note that the current PTD gets replaced by IdlePTD when the |
| 1131 | * task switch occurs. This means that the stack that was active at |
| 1132 | * the time of the double fault is not available at <kstack> unless |
| 1133 | * the machine was idle when the double fault occurred. The downside |
| 1134 | * of this is that "trace <ebp>" in ddb won't work. |
| 1135 | */ |
| 1136 | static __inline |
| 1137 | int |
| 1138 | in_kstack_guard(register_t rptr) |
| 1139 | { |
| 1140 | thread_t td = curthread; |
| 1141 | |
| 1142 | if ((char *)rptr >= td->td_kstack && |
| 1143 | (char *)rptr < td->td_kstack + PAGE_SIZE) { |
| 1144 | return 1; |
| 1145 | } |
| 1146 | return 0; |
| 1147 | } |
| 1148 | |
| 1149 | void |
| 1150 | dblfault_handler(void) |
| 1151 | { |
| 1152 | struct mdglobaldata *gd = mdcpu; |
| 1153 | |
| 1154 | if (in_kstack_guard(gd->gd_common_tss.tss_esp) || |
| 1155 | in_kstack_guard(gd->gd_common_tss.tss_ebp)) { |
| 1156 | kprintf("DOUBLE FAULT - KERNEL STACK GUARD HIT!\n"); |
| 1157 | } else { |
| 1158 | kprintf("DOUBLE FAULT:\n"); |
| 1159 | } |
| 1160 | kprintf("eip = 0x%x\n", gd->gd_common_tss.tss_eip); |
| 1161 | kprintf("esp = 0x%x\n", gd->gd_common_tss.tss_esp); |
| 1162 | kprintf("ebp = 0x%x\n", gd->gd_common_tss.tss_ebp); |
| 1163 | /* three separate prints in case of a trap on an unmapped page */ |
| 1164 | kprintf("cpuid = %d; ", gd->mi.gd_cpuid); |
| 1165 | kprintf("lapic.id = %08x\n", lapic->id); |
| 1166 | panic("double fault"); |
| 1167 | } |
| 1168 | |
| 1169 | /* |
| 1170 | * syscall2 - MP aware system call request C handler |
| 1171 | * |
| 1172 | * A system call is essentially treated as a trap. The MP lock is not |
| 1173 | * held on entry or return. We are responsible for handling ASTs |
| 1174 | * (e.g. a task switch) prior to return. |
| 1175 | * |
| 1176 | * MPSAFE |
| 1177 | */ |
| 1178 | void |
| 1179 | syscall2(struct trapframe *frame) |
| 1180 | { |
| 1181 | struct thread *td = curthread; |
| 1182 | struct proc *p = td->td_proc; |
| 1183 | struct lwp *lp = td->td_lwp; |
| 1184 | caddr_t params; |
| 1185 | struct sysent *callp; |
| 1186 | register_t orig_tf_eflags; |
| 1187 | int sticks; |
| 1188 | int error; |
| 1189 | int narg; |
| 1190 | #ifdef INVARIANTS |
| 1191 | int crit_count = td->td_critcount; |
| 1192 | #endif |
| 1193 | int have_mplock = 0; |
| 1194 | u_int code; |
| 1195 | union sysunion args; |
| 1196 | |
| 1197 | #ifdef DIAGNOSTIC |
| 1198 | if (ISPL(frame->tf_cs) != SEL_UPL) { |
| 1199 | get_mplock(); |
| 1200 | panic("syscall"); |
| 1201 | /* NOT REACHED */ |
| 1202 | } |
| 1203 | #endif |
| 1204 | |
| 1205 | KTR_LOG(kernentry_syscall, p->p_pid, lp->lwp_tid, |
| 1206 | frame->tf_eax); |
| 1207 | |
| 1208 | userenter(td, p); /* lazy raise our priority */ |
| 1209 | |
| 1210 | /* |
| 1211 | * Misc |
| 1212 | */ |
| 1213 | sticks = (int)td->td_sticks; |
| 1214 | orig_tf_eflags = frame->tf_eflags; |
| 1215 | |
| 1216 | /* |
| 1217 | * Virtual kernel intercept - if a VM context managed by a virtual |
| 1218 | * kernel issues a system call the virtual kernel handles it, not us. |
| 1219 | * Restore the virtual kernel context and return from its system |
| 1220 | * call. The current frame is copied out to the virtual kernel. |
| 1221 | */ |
| 1222 | if (lp->lwp_vkernel && lp->lwp_vkernel->ve) { |
| 1223 | vkernel_trap(lp, frame); |
| 1224 | error = EJUSTRETURN; |
| 1225 | callp = NULL; |
| 1226 | goto out; |
| 1227 | } |
| 1228 | |
| 1229 | /* |
| 1230 | * Get the system call parameters and account for time |
| 1231 | */ |
| 1232 | lp->lwp_md.md_regs = frame; |
| 1233 | params = (caddr_t)frame->tf_esp + sizeof(int); |
| 1234 | code = frame->tf_eax; |
| 1235 | |
| 1236 | if (p->p_sysent->sv_prepsyscall) { |
| 1237 | (*p->p_sysent->sv_prepsyscall)( |
| 1238 | frame, (int *)(&args.nosys.sysmsg + 1), |
| 1239 | &code, ¶ms); |
| 1240 | } else { |
| 1241 | /* |
| 1242 | * Need to check if this is a 32 bit or 64 bit syscall. |
| 1243 | * fuword is MP aware. |
| 1244 | */ |
| 1245 | if (code == SYS_syscall) { |
| 1246 | /* |
| 1247 | * Code is first argument, followed by actual args. |
| 1248 | */ |
| 1249 | code = fuword(params); |
| 1250 | params += sizeof(int); |
| 1251 | } else if (code == SYS___syscall) { |
| 1252 | /* |
| 1253 | * Like syscall, but code is a quad, so as to maintain |
| 1254 | * quad alignment for the rest of the arguments. |
| 1255 | */ |
| 1256 | code = fuword(params); |
| 1257 | params += sizeof(quad_t); |
| 1258 | } |
| 1259 | } |
| 1260 | |
| 1261 | code &= p->p_sysent->sv_mask; |
| 1262 | |
| 1263 | if (code >= p->p_sysent->sv_size) |
| 1264 | callp = &p->p_sysent->sv_table[0]; |
| 1265 | else |
| 1266 | callp = &p->p_sysent->sv_table[code]; |
| 1267 | |
| 1268 | narg = callp->sy_narg & SYF_ARGMASK; |
| 1269 | |
| 1270 | #if 0 |
| 1271 | if (p->p_sysent->sv_name[0] == 'L') |
| 1272 | kprintf("Linux syscall, code = %d\n", code); |
| 1273 | #endif |
| 1274 | |
| 1275 | /* |
| 1276 | * copyin is MP aware, but the tracing code is not |
| 1277 | */ |
| 1278 | if (narg && params) { |
| 1279 | error = copyin(params, (caddr_t)(&args.nosys.sysmsg + 1), |
| 1280 | narg * sizeof(register_t)); |
| 1281 | if (error) { |
| 1282 | #ifdef KTRACE |
| 1283 | if (KTRPOINT(td, KTR_SYSCALL)) { |
| 1284 | MAKEMPSAFE(have_mplock); |
| 1285 | |
| 1286 | ktrsyscall(lp, code, narg, |
| 1287 | (void *)(&args.nosys.sysmsg + 1)); |
| 1288 | } |
| 1289 | #endif |
| 1290 | goto bad; |
| 1291 | } |
| 1292 | } |
| 1293 | |
| 1294 | #ifdef KTRACE |
| 1295 | if (KTRPOINT(td, KTR_SYSCALL)) { |
| 1296 | MAKEMPSAFE(have_mplock); |
| 1297 | ktrsyscall(lp, code, narg, (void *)(&args.nosys.sysmsg + 1)); |
| 1298 | } |
| 1299 | #endif |
| 1300 | |
| 1301 | /* |
| 1302 | * For traditional syscall code edx is left untouched when 32 bit |
| 1303 | * results are returned. Since edx is loaded from fds[1] when the |
| 1304 | * system call returns we pre-set it here. |
| 1305 | */ |
| 1306 | args.sysmsg_fds[0] = 0; |
| 1307 | args.sysmsg_fds[1] = frame->tf_edx; |
| 1308 | |
| 1309 | /* |
| 1310 | * The syscall might manipulate the trap frame. If it does it |
| 1311 | * will probably return EJUSTRETURN. |
| 1312 | */ |
| 1313 | args.sysmsg_frame = frame; |
| 1314 | |
| 1315 | STOPEVENT(p, S_SCE, narg); /* MP aware */ |
| 1316 | |
| 1317 | /* |
| 1318 | * NOTE: All system calls run MPSAFE now. The system call itself |
| 1319 | * is responsible for getting the MP lock. |
| 1320 | */ |
| 1321 | error = (*callp->sy_call)(&args); |
| 1322 | |
| 1323 | out: |
| 1324 | /* |
| 1325 | * MP SAFE (we may or may not have the MP lock at this point) |
| 1326 | */ |
| 1327 | switch (error) { |
| 1328 | case 0: |
| 1329 | /* |
| 1330 | * Reinitialize proc pointer `p' as it may be different |
| 1331 | * if this is a child returning from fork syscall. |
| 1332 | */ |
| 1333 | p = curproc; |
| 1334 | lp = curthread->td_lwp; |
| 1335 | frame->tf_eax = args.sysmsg_fds[0]; |
| 1336 | frame->tf_edx = args.sysmsg_fds[1]; |
| 1337 | frame->tf_eflags &= ~PSL_C; |
| 1338 | break; |
| 1339 | case ERESTART: |
| 1340 | /* |
| 1341 | * Reconstruct pc, assuming lcall $X,y is 7 bytes, |
| 1342 | * int 0x80 is 2 bytes. We saved this in tf_err. |
| 1343 | */ |
| 1344 | frame->tf_eip -= frame->tf_err; |
| 1345 | break; |
| 1346 | case EJUSTRETURN: |
| 1347 | break; |
| 1348 | case EASYNC: |
| 1349 | panic("Unexpected EASYNC return value (for now)"); |
| 1350 | default: |
| 1351 | bad: |
| 1352 | if (p->p_sysent->sv_errsize) { |
| 1353 | if (error >= p->p_sysent->sv_errsize) |
| 1354 | error = -1; /* XXX */ |
| 1355 | else |
| 1356 | error = p->p_sysent->sv_errtbl[error]; |
| 1357 | } |
| 1358 | frame->tf_eax = error; |
| 1359 | frame->tf_eflags |= PSL_C; |
| 1360 | break; |
| 1361 | } |
| 1362 | |
| 1363 | /* |
| 1364 | * Traced syscall. trapsignal() is not MP aware. |
| 1365 | */ |
| 1366 | if ((orig_tf_eflags & PSL_T) && !(orig_tf_eflags & PSL_VM)) { |
| 1367 | MAKEMPSAFE(have_mplock); |
| 1368 | frame->tf_eflags &= ~PSL_T; |
| 1369 | trapsignal(lp, SIGTRAP, TRAP_TRACE); |
| 1370 | } |
| 1371 | |
| 1372 | /* |
| 1373 | * Handle reschedule and other end-of-syscall issues |
| 1374 | */ |
| 1375 | userret(lp, frame, sticks); |
| 1376 | |
| 1377 | #ifdef KTRACE |
| 1378 | if (KTRPOINT(td, KTR_SYSRET)) { |
| 1379 | MAKEMPSAFE(have_mplock); |
| 1380 | ktrsysret(lp, code, error, args.sysmsg_result); |
| 1381 | } |
| 1382 | #endif |
| 1383 | |
| 1384 | /* |
| 1385 | * This works because errno is findable through the |
| 1386 | * register set. If we ever support an emulation where this |
| 1387 | * is not the case, this code will need to be revisited. |
| 1388 | */ |
| 1389 | STOPEVENT(p, S_SCX, code); |
| 1390 | |
| 1391 | userexit(lp); |
| 1392 | /* |
| 1393 | * Release the MP lock if we had to get it |
| 1394 | */ |
| 1395 | if (have_mplock) |
| 1396 | rel_mplock(); |
| 1397 | KTR_LOG(kernentry_syscall_ret, p->p_pid, lp->lwp_tid, error); |
| 1398 | #ifdef INVARIANTS |
| 1399 | KASSERT(crit_count == td->td_critcount, |
| 1400 | ("syscall: critical section count mismatch! %d/%d", |
| 1401 | crit_count, td->td_pri)); |
| 1402 | KASSERT(&td->td_toks_base == td->td_toks_stop, |
| 1403 | ("syscall: extra tokens held after trap! %zd", |
| 1404 | td->td_toks_stop - &td->td_toks_base)); |
| 1405 | #endif |
| 1406 | } |
| 1407 | |
| 1408 | /* |
| 1409 | * NOTE: MP lock not held at any point. |
| 1410 | */ |
| 1411 | void |
| 1412 | fork_return(struct lwp *lp, struct trapframe *frame) |
| 1413 | { |
| 1414 | frame->tf_eax = 0; /* Child returns zero */ |
| 1415 | frame->tf_eflags &= ~PSL_C; /* success */ |
| 1416 | frame->tf_edx = 1; |
| 1417 | |
| 1418 | generic_lwp_return(lp, frame); |
| 1419 | KTR_LOG(kernentry_fork_ret, lp->lwp_proc->p_pid, lp->lwp_tid); |
| 1420 | } |
| 1421 | |
| 1422 | /* |
| 1423 | * Simplified back end of syscall(), used when returning from fork() |
| 1424 | * directly into user mode. |
| 1425 | * |
| 1426 | * This code will return back into the fork trampoline code which then |
| 1427 | * runs doreti. |
| 1428 | * |
| 1429 | * NOTE: The mplock is not held at any point. |
| 1430 | */ |
| 1431 | void |
| 1432 | generic_lwp_return(struct lwp *lp, struct trapframe *frame) |
| 1433 | { |
| 1434 | struct proc *p = lp->lwp_proc; |
| 1435 | |
| 1436 | /* |
| 1437 | * Newly forked processes are given a kernel priority. We have to |
| 1438 | * adjust the priority to a normal user priority and fake entry |
| 1439 | * into the kernel (call userenter()) to install a passive release |
| 1440 | * function just in case userret() decides to stop the process. This |
| 1441 | * can occur when ^Z races a fork. If we do not install the passive |
| 1442 | * release function the current process designation will not be |
| 1443 | * released when the thread goes to sleep. |
| 1444 | */ |
| 1445 | lwkt_setpri_self(TDPRI_USER_NORM); |
| 1446 | userenter(lp->lwp_thread, p); |
| 1447 | userret(lp, frame, 0); |
| 1448 | #ifdef KTRACE |
| 1449 | if (KTRPOINT(lp->lwp_thread, KTR_SYSRET)) |
| 1450 | ktrsysret(lp, SYS_fork, 0, 0); |
| 1451 | #endif |
| 1452 | lp->lwp_flags |= LWP_PASSIVE_ACQ; |
| 1453 | userexit(lp); |
| 1454 | lp->lwp_flags &= ~LWP_PASSIVE_ACQ; |
| 1455 | } |
| 1456 | |
| 1457 | /* |
| 1458 | * If PGEX_FPFAULT is set then set FP_VIRTFP in the PCB to force a T_DNA |
| 1459 | * fault (which is then passed back to the virtual kernel) if an attempt is |
| 1460 | * made to use the FP unit. |
| 1461 | * |
| 1462 | * XXX this is a fairly big hack. |
| 1463 | */ |
| 1464 | void |
| 1465 | set_vkernel_fp(struct trapframe *frame) |
| 1466 | { |
| 1467 | struct thread *td = curthread; |
| 1468 | |
| 1469 | if (frame->tf_xflags & PGEX_FPFAULT) { |
| 1470 | td->td_pcb->pcb_flags |= FP_VIRTFP; |
| 1471 | if (mdcpu->gd_npxthread == td) |
| 1472 | npxexit(); |
| 1473 | } else { |
| 1474 | td->td_pcb->pcb_flags &= ~FP_VIRTFP; |
| 1475 | } |
| 1476 | } |
| 1477 | |
| 1478 | /* |
| 1479 | * Called from vkernel_trap() to fixup the vkernel's syscall |
| 1480 | * frame for vmspace_ctl() return. |
| 1481 | */ |
| 1482 | void |
| 1483 | cpu_vkernel_trap(struct trapframe *frame, int error) |
| 1484 | { |
| 1485 | frame->tf_eax = error; |
| 1486 | if (error) |
| 1487 | frame->tf_eflags |= PSL_C; |
| 1488 | else |
| 1489 | frame->tf_eflags &= ~PSL_C; |
| 1490 | } |