| 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 | } |