| 1 | /*- |
| 2 | * Copyright (c) 1990, 1993 |
| 3 | * The Regents of the University of California. All rights reserved. |
| 4 | * Copyright (C) 1994, David Greenman |
| 5 | * Copyright (c) 2008 The DragonFly Project. |
| 6 | * Copyright (c) 2008 Jordan Gordeev. |
| 7 | * |
| 8 | * This code is derived from software contributed to Berkeley by |
| 9 | * the University of Utah, and William Jolitz. |
| 10 | * |
| 11 | * Redistribution and use in source and binary forms, with or without |
| 12 | * modification, are permitted provided that the following conditions |
| 13 | * are met: |
| 14 | * 1. Redistributions of source code must retain the above copyright |
| 15 | * notice, this list of conditions and the following disclaimer. |
| 16 | * 2. Redistributions in binary form must reproduce the above copyright |
| 17 | * notice, this list of conditions and the following disclaimer in the |
| 18 | * documentation and/or other materials provided with the distribution. |
| 19 | * 3. All advertising materials mentioning features or use of this software |
| 20 | * must display the following acknowledgement: |
| 21 | * This product includes software developed by the University of |
| 22 | * California, Berkeley and its contributors. |
| 23 | * 4. Neither the name of the University nor the names of its contributors |
| 24 | * may be used to endorse or promote products derived from this software |
| 25 | * without specific prior written permission. |
| 26 | * |
| 27 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
| 28 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| 29 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| 30 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
| 31 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| 32 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| 33 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| 34 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| 35 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| 36 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| 37 | * SUCH DAMAGE. |
| 38 | * |
| 39 | * from: @(#)trap.c 7.4 (Berkeley) 5/13/91 |
| 40 | * $FreeBSD: src/sys/i386/i386/trap.c,v 1.147.2.11 2003/02/27 19:09:59 luoqi Exp $ |
| 41 | */ |
| 42 | |
| 43 | /* |
| 44 | * x86_64 Trap and System call handling |
| 45 | */ |
| 46 | |
| 47 | #include "use_isa.h" |
| 48 | |
| 49 | #include "opt_ddb.h" |
| 50 | #include "opt_ktrace.h" |
| 51 | |
| 52 | #include <machine/frame.h> |
| 53 | #include <sys/param.h> |
| 54 | #include <sys/systm.h> |
| 55 | #include <sys/kernel.h> |
| 56 | #include <sys/kerneldump.h> |
| 57 | #include <sys/proc.h> |
| 58 | #include <sys/pioctl.h> |
| 59 | #include <sys/types.h> |
| 60 | #include <sys/signal2.h> |
| 61 | #include <sys/syscall.h> |
| 62 | #include <sys/sysctl.h> |
| 63 | #include <sys/sysent.h> |
| 64 | #include <sys/systm.h> |
| 65 | #ifdef KTRACE |
| 66 | #include <sys/ktrace.h> |
| 67 | #endif |
| 68 | #include <sys/ktr.h> |
| 69 | #include <sys/sysmsg.h> |
| 70 | #include <sys/sysproto.h> |
| 71 | #include <sys/sysunion.h> |
| 72 | |
| 73 | #include <vm/pmap.h> |
| 74 | #include <vm/vm.h> |
| 75 | #include <vm/vm_extern.h> |
| 76 | #include <vm/vm_kern.h> |
| 77 | #include <vm/vm_param.h> |
| 78 | #include <machine/cpu.h> |
| 79 | #include <machine/pcb.h> |
| 80 | #include <machine/smp.h> |
| 81 | #include <machine/thread.h> |
| 82 | #include <machine/clock.h> |
| 83 | #include <machine/vmparam.h> |
| 84 | #include <machine/md_var.h> |
| 85 | #include <machine_base/isa/isa_intr.h> |
| 86 | #include <machine_base/apic/lapic.h> |
| 87 | |
| 88 | #include <ddb/ddb.h> |
| 89 | |
| 90 | #include <sys/thread2.h> |
| 91 | #include <sys/mplock2.h> |
| 92 | |
| 93 | #define MAKEMPSAFE(have_mplock) \ |
| 94 | if (have_mplock == 0) { \ |
| 95 | get_mplock(); \ |
| 96 | have_mplock = 1; \ |
| 97 | } |
| 98 | |
| 99 | extern void trap(struct trapframe *frame); |
| 100 | |
| 101 | static int trap_pfault(struct trapframe *, int); |
| 102 | static void trap_fatal(struct trapframe *, vm_offset_t); |
| 103 | void dblfault_handler(struct trapframe *frame); |
| 104 | |
| 105 | #define MAX_TRAP_MSG 30 |
| 106 | static char *trap_msg[] = { |
| 107 | "", /* 0 unused */ |
| 108 | "privileged instruction fault", /* 1 T_PRIVINFLT */ |
| 109 | "", /* 2 unused */ |
| 110 | "breakpoint instruction fault", /* 3 T_BPTFLT */ |
| 111 | "", /* 4 unused */ |
| 112 | "", /* 5 unused */ |
| 113 | "arithmetic trap", /* 6 T_ARITHTRAP */ |
| 114 | "system forced exception", /* 7 T_ASTFLT */ |
| 115 | "", /* 8 unused */ |
| 116 | "general protection fault", /* 9 T_PROTFLT */ |
| 117 | "trace trap", /* 10 T_TRCTRAP */ |
| 118 | "", /* 11 unused */ |
| 119 | "page fault", /* 12 T_PAGEFLT */ |
| 120 | "", /* 13 unused */ |
| 121 | "alignment fault", /* 14 T_ALIGNFLT */ |
| 122 | "", /* 15 unused */ |
| 123 | "", /* 16 unused */ |
| 124 | "", /* 17 unused */ |
| 125 | "integer divide fault", /* 18 T_DIVIDE */ |
| 126 | "non-maskable interrupt trap", /* 19 T_NMI */ |
| 127 | "overflow trap", /* 20 T_OFLOW */ |
| 128 | "FPU bounds check fault", /* 21 T_BOUND */ |
| 129 | "FPU device not available", /* 22 T_DNA */ |
| 130 | "double fault", /* 23 T_DOUBLEFLT */ |
| 131 | "FPU operand fetch fault", /* 24 T_FPOPFLT */ |
| 132 | "invalid TSS fault", /* 25 T_TSSFLT */ |
| 133 | "segment not present fault", /* 26 T_SEGNPFLT */ |
| 134 | "stack fault", /* 27 T_STKFLT */ |
| 135 | "machine check trap", /* 28 T_MCHK */ |
| 136 | "SIMD floating-point exception", /* 29 T_XMMFLT */ |
| 137 | "reserved (unknown) fault", /* 30 T_RESERVED */ |
| 138 | }; |
| 139 | |
| 140 | #ifdef DDB |
| 141 | static int ddb_on_nmi = 1; |
| 142 | SYSCTL_INT(_machdep, OID_AUTO, ddb_on_nmi, CTLFLAG_RW, |
| 143 | &ddb_on_nmi, 0, "Go to DDB on NMI"); |
| 144 | static int ddb_on_seg_fault = 0; |
| 145 | SYSCTL_INT(_machdep, OID_AUTO, ddb_on_seg_fault, CTLFLAG_RW, |
| 146 | &ddb_on_seg_fault, 0, "Go to DDB on user seg-fault"); |
| 147 | static int freeze_on_seg_fault = 0; |
| 148 | SYSCTL_INT(_machdep, OID_AUTO, freeze_on_seg_fault, CTLFLAG_RW, |
| 149 | &freeze_on_seg_fault, 0, "Go to DDB on user seg-fault"); |
| 150 | #endif |
| 151 | static int panic_on_nmi = 1; |
| 152 | SYSCTL_INT(_machdep, OID_AUTO, panic_on_nmi, CTLFLAG_RW, |
| 153 | &panic_on_nmi, 0, "Panic on NMI"); |
| 154 | static int fast_release; |
| 155 | SYSCTL_INT(_machdep, OID_AUTO, fast_release, CTLFLAG_RW, |
| 156 | &fast_release, 0, "Passive Release was optimal"); |
| 157 | static int slow_release; |
| 158 | SYSCTL_INT(_machdep, OID_AUTO, slow_release, CTLFLAG_RW, |
| 159 | &slow_release, 0, "Passive Release was nonoptimal"); |
| 160 | |
| 161 | /* |
| 162 | * System call debugging records the worst-case system call |
| 163 | * overhead (inclusive of blocking), but may be inaccurate. |
| 164 | */ |
| 165 | /*#define SYSCALL_DEBUG*/ |
| 166 | #ifdef SYSCALL_DEBUG |
| 167 | uint64_t SysCallsWorstCase[SYS_MAXSYSCALL]; |
| 168 | #endif |
| 169 | |
| 170 | /* |
| 171 | * Passively intercepts the thread switch function to increase |
| 172 | * the thread priority from a user priority to a kernel priority, reducing |
| 173 | * syscall and trap overhead for the case where no switch occurs. |
| 174 | * |
| 175 | * Synchronizes td_ucred with p_ucred. This is used by system calls, |
| 176 | * signal handling, faults, AST traps, and anything else that enters the |
| 177 | * kernel from userland and provides the kernel with a stable read-only |
| 178 | * copy of the process ucred. |
| 179 | */ |
| 180 | static __inline void |
| 181 | userenter(struct thread *curtd, struct proc *curp) |
| 182 | { |
| 183 | struct ucred *ocred; |
| 184 | struct ucred *ncred; |
| 185 | |
| 186 | curtd->td_release = lwkt_passive_release; |
| 187 | |
| 188 | if (curtd->td_ucred != curp->p_ucred) { |
| 189 | ncred = crhold(curp->p_ucred); |
| 190 | ocred = curtd->td_ucred; |
| 191 | curtd->td_ucred = ncred; |
| 192 | if (ocred) |
| 193 | crfree(ocred); |
| 194 | } |
| 195 | |
| 196 | #ifdef DDB |
| 197 | /* |
| 198 | * Debugging, remove top two user stack pages to catch kernel faults |
| 199 | */ |
| 200 | if (freeze_on_seg_fault > 1 && curtd->td_lwp) { |
| 201 | pmap_remove(vmspace_pmap(curtd->td_lwp->lwp_vmspace), |
| 202 | 0x00007FFFFFFFD000LU, |
| 203 | 0x0000800000000000LU); |
| 204 | } |
| 205 | #endif |
| 206 | } |
| 207 | |
| 208 | /* |
| 209 | * Handle signals, upcalls, profiling, and other AST's and/or tasks that |
| 210 | * must be completed before we can return to or try to return to userland. |
| 211 | * |
| 212 | * Note that td_sticks is a 64 bit quantity, but there's no point doing 64 |
| 213 | * arithmatic on the delta calculation so the absolute tick values are |
| 214 | * truncated to an integer. |
| 215 | */ |
| 216 | static void |
| 217 | userret(struct lwp *lp, struct trapframe *frame, int sticks) |
| 218 | { |
| 219 | struct proc *p = lp->lwp_proc; |
| 220 | int sig; |
| 221 | |
| 222 | /* |
| 223 | * Charge system time if profiling. Note: times are in microseconds. |
| 224 | * This may do a copyout and block, so do it first even though it |
| 225 | * means some system time will be charged as user time. |
| 226 | */ |
| 227 | if (p->p_flags & P_PROFIL) { |
| 228 | addupc_task(p, frame->tf_rip, |
| 229 | (u_int)((int)lp->lwp_thread->td_sticks - sticks)); |
| 230 | } |
| 231 | |
| 232 | recheck: |
| 233 | /* |
| 234 | * If the jungle wants us dead, so be it. |
| 235 | */ |
| 236 | if (lp->lwp_mpflags & LWP_MP_WEXIT) { |
| 237 | lwkt_gettoken(&p->p_token); |
| 238 | lwp_exit(0); |
| 239 | lwkt_reltoken(&p->p_token); /* NOT REACHED */ |
| 240 | } |
| 241 | |
| 242 | /* |
| 243 | * Block here if we are in a stopped state. |
| 244 | */ |
| 245 | if (p->p_stat == SSTOP || dump_stop_usertds) { |
| 246 | lwkt_gettoken(&p->p_token); |
| 247 | tstop(); |
| 248 | lwkt_reltoken(&p->p_token); |
| 249 | goto recheck; |
| 250 | } |
| 251 | |
| 252 | /* |
| 253 | * Post any pending upcalls. If running a virtual kernel be sure |
| 254 | * to restore the virtual kernel's vmspace before posting the upcall. |
| 255 | */ |
| 256 | if (p->p_flags & (P_SIGVTALRM | P_SIGPROF | P_UPCALLPEND)) { |
| 257 | lwkt_gettoken(&p->p_token); |
| 258 | if (p->p_flags & P_SIGVTALRM) { |
| 259 | p->p_flags &= ~P_SIGVTALRM; |
| 260 | ksignal(p, SIGVTALRM); |
| 261 | } |
| 262 | if (p->p_flags & P_SIGPROF) { |
| 263 | p->p_flags &= ~P_SIGPROF; |
| 264 | ksignal(p, SIGPROF); |
| 265 | } |
| 266 | if (p->p_flags & P_UPCALLPEND) { |
| 267 | p->p_flags &= ~P_UPCALLPEND; |
| 268 | postupcall(lp); |
| 269 | } |
| 270 | lwkt_reltoken(&p->p_token); |
| 271 | goto recheck; |
| 272 | } |
| 273 | |
| 274 | /* |
| 275 | * Post any pending signals. If running a virtual kernel be sure |
| 276 | * to restore the virtual kernel's vmspace before posting the signal. |
| 277 | * |
| 278 | * WARNING! postsig() can exit and not return. |
| 279 | */ |
| 280 | if ((sig = CURSIG_TRACE(lp)) != 0) { |
| 281 | lwkt_gettoken(&p->p_token); |
| 282 | postsig(sig); |
| 283 | lwkt_reltoken(&p->p_token); |
| 284 | goto recheck; |
| 285 | } |
| 286 | |
| 287 | /* |
| 288 | * block here if we are swapped out, but still process signals |
| 289 | * (such as SIGKILL). proc0 (the swapin scheduler) is already |
| 290 | * aware of our situation, we do not have to wake it up. |
| 291 | */ |
| 292 | if (p->p_flags & P_SWAPPEDOUT) { |
| 293 | lwkt_gettoken(&p->p_token); |
| 294 | get_mplock(); |
| 295 | p->p_flags |= P_SWAPWAIT; |
| 296 | swapin_request(); |
| 297 | if (p->p_flags & P_SWAPWAIT) |
| 298 | tsleep(p, PCATCH, "SWOUT", 0); |
| 299 | p->p_flags &= ~P_SWAPWAIT; |
| 300 | rel_mplock(); |
| 301 | lwkt_reltoken(&p->p_token); |
| 302 | goto recheck; |
| 303 | } |
| 304 | |
| 305 | /* |
| 306 | * In a multi-threaded program it is possible for a thread to change |
| 307 | * signal state during a system call which temporarily changes the |
| 308 | * signal mask. In this case postsig() might not be run and we |
| 309 | * have to restore the mask ourselves. |
| 310 | */ |
| 311 | if (lp->lwp_flags & LWP_OLDMASK) { |
| 312 | lp->lwp_flags &= ~LWP_OLDMASK; |
| 313 | lp->lwp_sigmask = lp->lwp_oldsigmask; |
| 314 | goto recheck; |
| 315 | } |
| 316 | } |
| 317 | |
| 318 | /* |
| 319 | * Cleanup from userenter and any passive release that might have occured. |
| 320 | * We must reclaim the current-process designation before we can return |
| 321 | * to usermode. We also handle both LWKT and USER reschedule requests. |
| 322 | */ |
| 323 | static __inline void |
| 324 | userexit(struct lwp *lp) |
| 325 | { |
| 326 | struct thread *td = lp->lwp_thread; |
| 327 | /* globaldata_t gd = td->td_gd; */ |
| 328 | |
| 329 | /* |
| 330 | * Handle stop requests at kernel priority. Any requests queued |
| 331 | * after this loop will generate another AST. |
| 332 | */ |
| 333 | while (lp->lwp_proc->p_stat == SSTOP) { |
| 334 | lwkt_gettoken(&lp->lwp_proc->p_token); |
| 335 | tstop(); |
| 336 | lwkt_reltoken(&lp->lwp_proc->p_token); |
| 337 | } |
| 338 | |
| 339 | /* |
| 340 | * Reduce our priority in preparation for a return to userland. If |
| 341 | * our passive release function was still in place, our priority was |
| 342 | * never raised and does not need to be reduced. |
| 343 | */ |
| 344 | lwkt_passive_recover(td); |
| 345 | |
| 346 | /* WARNING: we may have migrated cpu's */ |
| 347 | /* gd = td->td_gd; */ |
| 348 | |
| 349 | /* |
| 350 | * Become the current user scheduled process if we aren't already, |
| 351 | * and deal with reschedule requests and other factors. |
| 352 | */ |
| 353 | lp->lwp_proc->p_usched->acquire_curproc(lp); |
| 354 | } |
| 355 | |
| 356 | #if !defined(KTR_KERNENTRY) |
| 357 | #define KTR_KERNENTRY KTR_ALL |
| 358 | #endif |
| 359 | KTR_INFO_MASTER(kernentry); |
| 360 | KTR_INFO(KTR_KERNENTRY, kernentry, trap, 0, |
| 361 | "TRAP(pid %d, tid %d, trapno %ld, eva %lu)", |
| 362 | pid_t pid, lwpid_t tid, register_t trapno, vm_offset_t eva); |
| 363 | KTR_INFO(KTR_KERNENTRY, kernentry, trap_ret, 0, "TRAP_RET(pid %d, tid %d)", |
| 364 | pid_t pid, lwpid_t tid); |
| 365 | KTR_INFO(KTR_KERNENTRY, kernentry, syscall, 0, "SYSC(pid %d, tid %d, nr %ld)", |
| 366 | pid_t pid, lwpid_t tid, register_t trapno); |
| 367 | KTR_INFO(KTR_KERNENTRY, kernentry, syscall_ret, 0, "SYSRET(pid %d, tid %d, err %d)", |
| 368 | pid_t pid, lwpid_t tid, int err); |
| 369 | KTR_INFO(KTR_KERNENTRY, kernentry, fork_ret, 0, "FORKRET(pid %d, tid %d)", |
| 370 | pid_t pid, lwpid_t tid); |
| 371 | |
| 372 | /* |
| 373 | * Exception, fault, and trap interface to the kernel. |
| 374 | * This common code is called from assembly language IDT gate entry |
| 375 | * routines that prepare a suitable stack frame, and restore this |
| 376 | * frame after the exception has been processed. |
| 377 | * |
| 378 | * This function is also called from doreti in an interlock to handle ASTs. |
| 379 | * For example: hardwareint->INTROUTINE->(set ast)->doreti->trap |
| 380 | * |
| 381 | * NOTE! We have to retrieve the fault address prior to obtaining the |
| 382 | * MP lock because get_mplock() may switch out. YYY cr2 really ought |
| 383 | * to be retrieved by the assembly code, not here. |
| 384 | * |
| 385 | * XXX gd_trap_nesting_level currently prevents lwkt_switch() from panicing |
| 386 | * if an attempt is made to switch from a fast interrupt or IPI. This is |
| 387 | * necessary to properly take fatal kernel traps on SMP machines if |
| 388 | * get_mplock() has to block. |
| 389 | */ |
| 390 | |
| 391 | void |
| 392 | trap(struct trapframe *frame) |
| 393 | { |
| 394 | struct globaldata *gd = mycpu; |
| 395 | struct thread *td = gd->gd_curthread; |
| 396 | struct lwp *lp = td->td_lwp; |
| 397 | struct proc *p; |
| 398 | int sticks = 0; |
| 399 | int i = 0, ucode = 0, type, code; |
| 400 | int have_mplock = 0; |
| 401 | #ifdef INVARIANTS |
| 402 | int crit_count = td->td_critcount; |
| 403 | lwkt_tokref_t curstop = td->td_toks_stop; |
| 404 | #endif |
| 405 | vm_offset_t eva; |
| 406 | |
| 407 | p = td->td_proc; |
| 408 | clear_quickret(); |
| 409 | |
| 410 | #ifdef DDB |
| 411 | /* |
| 412 | * We need to allow T_DNA faults when the debugger is active since |
| 413 | * some dumping paths do large bcopy() which use the floating |
| 414 | * point registers for faster copying. |
| 415 | */ |
| 416 | if (db_active && frame->tf_trapno != T_DNA) { |
| 417 | eva = (frame->tf_trapno == T_PAGEFLT ? frame->tf_addr : 0); |
| 418 | ++gd->gd_trap_nesting_level; |
| 419 | MAKEMPSAFE(have_mplock); |
| 420 | trap_fatal(frame, eva); |
| 421 | --gd->gd_trap_nesting_level; |
| 422 | goto out2; |
| 423 | } |
| 424 | #endif |
| 425 | |
| 426 | eva = 0; |
| 427 | |
| 428 | if ((frame->tf_rflags & PSL_I) == 0) { |
| 429 | /* |
| 430 | * Buggy application or kernel code has disabled interrupts |
| 431 | * and then trapped. Enabling interrupts now is wrong, but |
| 432 | * it is better than running with interrupts disabled until |
| 433 | * they are accidentally enabled later. |
| 434 | */ |
| 435 | type = frame->tf_trapno; |
| 436 | if (ISPL(frame->tf_cs) == SEL_UPL) { |
| 437 | MAKEMPSAFE(have_mplock); |
| 438 | /* JG curproc can be NULL */ |
| 439 | kprintf( |
| 440 | "pid %ld (%s): trap %d with interrupts disabled\n", |
| 441 | (long)curproc->p_pid, curproc->p_comm, type); |
| 442 | } else if (type != T_NMI && type != T_BPTFLT && |
| 443 | type != T_TRCTRAP) { |
| 444 | /* |
| 445 | * XXX not quite right, since this may be for a |
| 446 | * multiple fault in user mode. |
| 447 | */ |
| 448 | MAKEMPSAFE(have_mplock); |
| 449 | kprintf("kernel trap %d with interrupts disabled\n", |
| 450 | type); |
| 451 | } |
| 452 | cpu_enable_intr(); |
| 453 | } |
| 454 | |
| 455 | type = frame->tf_trapno; |
| 456 | code = frame->tf_err; |
| 457 | |
| 458 | if (ISPL(frame->tf_cs) == SEL_UPL) { |
| 459 | /* user trap */ |
| 460 | |
| 461 | KTR_LOG(kernentry_trap, p->p_pid, lp->lwp_tid, |
| 462 | frame->tf_trapno, eva); |
| 463 | |
| 464 | userenter(td, p); |
| 465 | |
| 466 | sticks = (int)td->td_sticks; |
| 467 | KASSERT(lp->lwp_md.md_regs == frame, |
| 468 | ("Frame mismatch %p %p", lp->lwp_md.md_regs, frame)); |
| 469 | |
| 470 | switch (type) { |
| 471 | case T_PRIVINFLT: /* privileged instruction fault */ |
| 472 | i = SIGILL; |
| 473 | ucode = ILL_PRVOPC; |
| 474 | break; |
| 475 | |
| 476 | case T_BPTFLT: /* bpt instruction fault */ |
| 477 | case T_TRCTRAP: /* trace trap */ |
| 478 | frame->tf_rflags &= ~PSL_T; |
| 479 | i = SIGTRAP; |
| 480 | ucode = (type == T_TRCTRAP ? TRAP_TRACE : TRAP_BRKPT); |
| 481 | break; |
| 482 | |
| 483 | case T_ARITHTRAP: /* arithmetic trap */ |
| 484 | ucode = code; |
| 485 | i = SIGFPE; |
| 486 | break; |
| 487 | |
| 488 | case T_ASTFLT: /* Allow process switch */ |
| 489 | mycpu->gd_cnt.v_soft++; |
| 490 | if (mycpu->gd_reqflags & RQF_AST_OWEUPC) { |
| 491 | atomic_clear_int(&mycpu->gd_reqflags, |
| 492 | RQF_AST_OWEUPC); |
| 493 | addupc_task(p, p->p_prof.pr_addr, |
| 494 | p->p_prof.pr_ticks); |
| 495 | } |
| 496 | goto out; |
| 497 | |
| 498 | case T_PROTFLT: /* general protection fault */ |
| 499 | i = SIGBUS; |
| 500 | ucode = BUS_OBJERR; |
| 501 | break; |
| 502 | case T_STKFLT: /* stack fault */ |
| 503 | case T_SEGNPFLT: /* segment not present fault */ |
| 504 | i = SIGBUS; |
| 505 | ucode = BUS_ADRERR; |
| 506 | break; |
| 507 | case T_TSSFLT: /* invalid TSS fault */ |
| 508 | case T_DOUBLEFLT: /* double fault */ |
| 509 | default: |
| 510 | i = SIGBUS; |
| 511 | ucode = BUS_OBJERR; |
| 512 | break; |
| 513 | |
| 514 | case T_PAGEFLT: /* page fault */ |
| 515 | i = trap_pfault(frame, TRUE); |
| 516 | if (frame->tf_rip == 0) { |
| 517 | kprintf("T_PAGEFLT: Warning %%rip == 0!\n"); |
| 518 | #ifdef DDB |
| 519 | while (freeze_on_seg_fault) |
| 520 | tsleep(p, 0, "freeze", hz * 20); |
| 521 | #endif |
| 522 | } |
| 523 | if (i == -1 || i == 0) |
| 524 | goto out; |
| 525 | |
| 526 | |
| 527 | if (i == SIGSEGV) |
| 528 | ucode = SEGV_MAPERR; |
| 529 | else { |
| 530 | i = SIGSEGV; |
| 531 | ucode = SEGV_ACCERR; |
| 532 | } |
| 533 | break; |
| 534 | |
| 535 | case T_DIVIDE: /* integer divide fault */ |
| 536 | ucode = FPE_INTDIV; |
| 537 | i = SIGFPE; |
| 538 | break; |
| 539 | |
| 540 | #if NISA > 0 |
| 541 | case T_NMI: |
| 542 | MAKEMPSAFE(have_mplock); |
| 543 | /* machine/parity/power fail/"kitchen sink" faults */ |
| 544 | if (isa_nmi(code) == 0) { |
| 545 | #ifdef DDB |
| 546 | /* |
| 547 | * NMI can be hooked up to a pushbutton |
| 548 | * for debugging. |
| 549 | */ |
| 550 | if (ddb_on_nmi) { |
| 551 | kprintf ("NMI ... going to debugger\n"); |
| 552 | kdb_trap(type, 0, frame); |
| 553 | } |
| 554 | #endif /* DDB */ |
| 555 | goto out2; |
| 556 | } else if (panic_on_nmi) |
| 557 | panic("NMI indicates hardware failure"); |
| 558 | break; |
| 559 | #endif /* NISA > 0 */ |
| 560 | |
| 561 | case T_OFLOW: /* integer overflow fault */ |
| 562 | ucode = FPE_INTOVF; |
| 563 | i = SIGFPE; |
| 564 | break; |
| 565 | |
| 566 | case T_BOUND: /* bounds check fault */ |
| 567 | ucode = FPE_FLTSUB; |
| 568 | i = SIGFPE; |
| 569 | break; |
| 570 | |
| 571 | case T_DNA: |
| 572 | /* |
| 573 | * Virtual kernel intercept - pass the DNA exception |
| 574 | * to the virtual kernel if it asked to handle it. |
| 575 | * This occurs when the virtual kernel is holding |
| 576 | * onto the FP context for a different emulated |
| 577 | * process then the one currently running. |
| 578 | * |
| 579 | * We must still call npxdna() since we may have |
| 580 | * saved FP state that the virtual kernel needs |
| 581 | * to hand over to a different emulated process. |
| 582 | */ |
| 583 | if (lp->lwp_vkernel && lp->lwp_vkernel->ve && |
| 584 | (td->td_pcb->pcb_flags & FP_VIRTFP) |
| 585 | ) { |
| 586 | npxdna(); |
| 587 | break; |
| 588 | } |
| 589 | |
| 590 | /* |
| 591 | * The kernel may have switched out the FP unit's |
| 592 | * state, causing the user process to take a fault |
| 593 | * when it tries to use the FP unit. Restore the |
| 594 | * state here |
| 595 | */ |
| 596 | if (npxdna()) |
| 597 | goto out; |
| 598 | i = SIGFPE; |
| 599 | ucode = FPE_FPU_NP_TRAP; |
| 600 | break; |
| 601 | |
| 602 | case T_FPOPFLT: /* FPU operand fetch fault */ |
| 603 | ucode = ILL_COPROC; |
| 604 | i = SIGILL; |
| 605 | break; |
| 606 | |
| 607 | case T_XMMFLT: /* SIMD floating-point exception */ |
| 608 | ucode = 0; /* XXX */ |
| 609 | i = SIGFPE; |
| 610 | break; |
| 611 | } |
| 612 | } else { |
| 613 | /* kernel trap */ |
| 614 | |
| 615 | switch (type) { |
| 616 | case T_PAGEFLT: /* page fault */ |
| 617 | trap_pfault(frame, FALSE); |
| 618 | goto out2; |
| 619 | |
| 620 | case T_DNA: |
| 621 | /* |
| 622 | * The kernel is apparently using fpu for copying. |
| 623 | * XXX this should be fatal unless the kernel has |
| 624 | * registered such use. |
| 625 | */ |
| 626 | if (npxdna()) |
| 627 | goto out2; |
| 628 | break; |
| 629 | |
| 630 | case T_STKFLT: /* stack fault */ |
| 631 | break; |
| 632 | |
| 633 | case T_PROTFLT: /* general protection fault */ |
| 634 | case T_SEGNPFLT: /* segment not present fault */ |
| 635 | /* |
| 636 | * Invalid segment selectors and out of bounds |
| 637 | * %rip's and %rsp's can be set up in user mode. |
| 638 | * This causes a fault in kernel mode when the |
| 639 | * kernel tries to return to user mode. We want |
| 640 | * to get this fault so that we can fix the |
| 641 | * problem here and not have to check all the |
| 642 | * selectors and pointers when the user changes |
| 643 | * them. |
| 644 | */ |
| 645 | if (mycpu->gd_intr_nesting_level == 0) { |
| 646 | /* |
| 647 | * NOTE: in 64-bit mode traps push rsp/ss |
| 648 | * even if no ring change occurs. |
| 649 | */ |
| 650 | if (td->td_pcb->pcb_onfault && |
| 651 | td->td_pcb->pcb_onfault_sp == |
| 652 | frame->tf_rsp) { |
| 653 | frame->tf_rip = (register_t) |
| 654 | td->td_pcb->pcb_onfault; |
| 655 | goto out2; |
| 656 | } |
| 657 | if (frame->tf_rip == (long)doreti_iret) { |
| 658 | frame->tf_rip = (long)doreti_iret_fault; |
| 659 | goto out2; |
| 660 | } |
| 661 | } |
| 662 | break; |
| 663 | |
| 664 | case T_TSSFLT: |
| 665 | /* |
| 666 | * PSL_NT can be set in user mode and isn't cleared |
| 667 | * automatically when the kernel is entered. This |
| 668 | * causes a TSS fault when the kernel attempts to |
| 669 | * `iret' because the TSS link is uninitialized. We |
| 670 | * want to get this fault so that we can fix the |
| 671 | * problem here and not every time the kernel is |
| 672 | * entered. |
| 673 | */ |
| 674 | if (frame->tf_rflags & PSL_NT) { |
| 675 | frame->tf_rflags &= ~PSL_NT; |
| 676 | goto out2; |
| 677 | } |
| 678 | break; |
| 679 | |
| 680 | case T_TRCTRAP: /* trace trap */ |
| 681 | #if 0 |
| 682 | if (frame->tf_rip == (int)IDTVEC(syscall)) { |
| 683 | /* |
| 684 | * We've just entered system mode via the |
| 685 | * syscall lcall. Continue single stepping |
| 686 | * silently until the syscall handler has |
| 687 | * saved the flags. |
| 688 | */ |
| 689 | goto out2; |
| 690 | } |
| 691 | if (frame->tf_rip == (int)IDTVEC(syscall) + 1) { |
| 692 | /* |
| 693 | * The syscall handler has now saved the |
| 694 | * flags. Stop single stepping it. |
| 695 | */ |
| 696 | frame->tf_rflags &= ~PSL_T; |
| 697 | goto out2; |
| 698 | } |
| 699 | #endif |
| 700 | |
| 701 | /* |
| 702 | * Ignore debug register trace traps due to |
| 703 | * accesses in the user's address space, which |
| 704 | * can happen under several conditions such as |
| 705 | * if a user sets a watchpoint on a buffer and |
| 706 | * then passes that buffer to a system call. |
| 707 | * We still want to get TRCTRAPS for addresses |
| 708 | * in kernel space because that is useful when |
| 709 | * debugging the kernel. |
| 710 | */ |
| 711 | #if JG |
| 712 | if (user_dbreg_trap()) { |
| 713 | /* |
| 714 | * Reset breakpoint bits because the |
| 715 | * processor doesn't |
| 716 | */ |
| 717 | /* XXX check upper bits here */ |
| 718 | load_dr6(rdr6() & 0xfffffff0); |
| 719 | goto out2; |
| 720 | } |
| 721 | #endif |
| 722 | /* |
| 723 | * FALLTHROUGH (TRCTRAP kernel mode, kernel address) |
| 724 | */ |
| 725 | case T_BPTFLT: |
| 726 | /* |
| 727 | * If DDB is enabled, let it handle the debugger trap. |
| 728 | * Otherwise, debugger traps "can't happen". |
| 729 | */ |
| 730 | ucode = TRAP_BRKPT; |
| 731 | #ifdef DDB |
| 732 | MAKEMPSAFE(have_mplock); |
| 733 | if (kdb_trap(type, 0, frame)) |
| 734 | goto out2; |
| 735 | #endif |
| 736 | break; |
| 737 | |
| 738 | #if NISA > 0 |
| 739 | case T_NMI: |
| 740 | MAKEMPSAFE(have_mplock); |
| 741 | /* machine/parity/power fail/"kitchen sink" faults */ |
| 742 | if (isa_nmi(code) == 0) { |
| 743 | #ifdef DDB |
| 744 | /* |
| 745 | * NMI can be hooked up to a pushbutton |
| 746 | * for debugging. |
| 747 | */ |
| 748 | if (ddb_on_nmi) { |
| 749 | kprintf ("NMI ... going to debugger\n"); |
| 750 | kdb_trap(type, 0, frame); |
| 751 | } |
| 752 | #endif /* DDB */ |
| 753 | goto out2; |
| 754 | } else if (panic_on_nmi == 0) |
| 755 | goto out2; |
| 756 | /* FALL THROUGH */ |
| 757 | #endif /* NISA > 0 */ |
| 758 | } |
| 759 | MAKEMPSAFE(have_mplock); |
| 760 | trap_fatal(frame, 0); |
| 761 | goto out2; |
| 762 | } |
| 763 | |
| 764 | /* |
| 765 | * Virtual kernel intercept - if the fault is directly related to a |
| 766 | * VM context managed by a virtual kernel then let the virtual kernel |
| 767 | * handle it. |
| 768 | */ |
| 769 | if (lp->lwp_vkernel && lp->lwp_vkernel->ve) { |
| 770 | vkernel_trap(lp, frame); |
| 771 | goto out; |
| 772 | } |
| 773 | |
| 774 | /* Translate fault for emulators (e.g. Linux) */ |
| 775 | if (*p->p_sysent->sv_transtrap) |
| 776 | i = (*p->p_sysent->sv_transtrap)(i, type); |
| 777 | |
| 778 | MAKEMPSAFE(have_mplock); |
| 779 | trapsignal(lp, i, ucode); |
| 780 | |
| 781 | #ifdef DEBUG |
| 782 | if (type <= MAX_TRAP_MSG) { |
| 783 | uprintf("fatal process exception: %s", |
| 784 | trap_msg[type]); |
| 785 | if ((type == T_PAGEFLT) || (type == T_PROTFLT)) |
| 786 | uprintf(", fault VA = 0x%lx", frame->tf_addr); |
| 787 | uprintf("\n"); |
| 788 | } |
| 789 | #endif |
| 790 | |
| 791 | out: |
| 792 | userret(lp, frame, sticks); |
| 793 | userexit(lp); |
| 794 | out2: ; |
| 795 | if (have_mplock) |
| 796 | rel_mplock(); |
| 797 | if (p != NULL && lp != NULL) |
| 798 | KTR_LOG(kernentry_trap_ret, p->p_pid, lp->lwp_tid); |
| 799 | #ifdef INVARIANTS |
| 800 | KASSERT(crit_count == td->td_critcount, |
| 801 | ("trap: critical section count mismatch! %d/%d", |
| 802 | crit_count, td->td_pri)); |
| 803 | KASSERT(curstop == td->td_toks_stop, |
| 804 | ("trap: extra tokens held after trap! %ld/%ld", |
| 805 | curstop - &td->td_toks_base, |
| 806 | td->td_toks_stop - &td->td_toks_base)); |
| 807 | #endif |
| 808 | } |
| 809 | |
| 810 | static int |
| 811 | trap_pfault(struct trapframe *frame, int usermode) |
| 812 | { |
| 813 | vm_offset_t va; |
| 814 | struct vmspace *vm = NULL; |
| 815 | vm_map_t map; |
| 816 | int rv = 0; |
| 817 | int fault_flags; |
| 818 | vm_prot_t ftype; |
| 819 | thread_t td = curthread; |
| 820 | struct lwp *lp = td->td_lwp; |
| 821 | struct proc *p; |
| 822 | |
| 823 | va = trunc_page(frame->tf_addr); |
| 824 | if (va >= VM_MIN_KERNEL_ADDRESS) { |
| 825 | /* |
| 826 | * Don't allow user-mode faults in kernel address space. |
| 827 | */ |
| 828 | if (usermode) { |
| 829 | fault_flags = -1; |
| 830 | ftype = -1; |
| 831 | goto nogo; |
| 832 | } |
| 833 | |
| 834 | map = &kernel_map; |
| 835 | } else { |
| 836 | /* |
| 837 | * This is a fault on non-kernel virtual memory. |
| 838 | * vm is initialized above to NULL. If curproc is NULL |
| 839 | * or curproc->p_vmspace is NULL the fault is fatal. |
| 840 | */ |
| 841 | if (lp != NULL) |
| 842 | vm = lp->lwp_vmspace; |
| 843 | |
| 844 | if (vm == NULL) { |
| 845 | fault_flags = -1; |
| 846 | ftype = -1; |
| 847 | goto nogo; |
| 848 | } |
| 849 | |
| 850 | /* |
| 851 | * Debugging, try to catch kernel faults on the user address space when not inside |
| 852 | * on onfault (e.g. copyin/copyout) routine. |
| 853 | */ |
| 854 | if (usermode == 0 && (td->td_pcb == NULL || |
| 855 | td->td_pcb->pcb_onfault == NULL)) { |
| 856 | #ifdef DDB |
| 857 | if (freeze_on_seg_fault) { |
| 858 | kprintf("trap_pfault: user address fault from kernel mode " |
| 859 | "%016lx\n", (long)frame->tf_addr); |
| 860 | while (freeze_on_seg_fault) |
| 861 | tsleep(&freeze_on_seg_fault, 0, "frzseg", hz * 20); |
| 862 | } |
| 863 | #endif |
| 864 | } |
| 865 | map = &vm->vm_map; |
| 866 | } |
| 867 | |
| 868 | /* |
| 869 | * PGEX_I is defined only if the execute disable bit capability is |
| 870 | * supported and enabled. |
| 871 | */ |
| 872 | if (frame->tf_err & PGEX_W) |
| 873 | ftype = VM_PROT_WRITE; |
| 874 | #if JG |
| 875 | else if ((frame->tf_err & PGEX_I) && pg_nx != 0) |
| 876 | ftype = VM_PROT_EXECUTE; |
| 877 | #endif |
| 878 | else |
| 879 | ftype = VM_PROT_READ; |
| 880 | |
| 881 | if (map != &kernel_map) { |
| 882 | /* |
| 883 | * Keep swapout from messing with us during this |
| 884 | * critical time. |
| 885 | */ |
| 886 | PHOLD(lp->lwp_proc); |
| 887 | |
| 888 | /* |
| 889 | * Issue fault |
| 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 |
| 904 | * kernel. |
| 905 | */ |
| 906 | fault_flags = VM_FAULT_NORMAL; |
| 907 | rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL); |
| 908 | } |
| 909 | if (rv == KERN_SUCCESS) |
| 910 | return (0); |
| 911 | nogo: |
| 912 | if (!usermode) { |
| 913 | /* |
| 914 | * NOTE: in 64-bit mode traps push rsp/ss |
| 915 | * even if no ring change occurs. |
| 916 | */ |
| 917 | if (td->td_pcb->pcb_onfault && |
| 918 | td->td_pcb->pcb_onfault_sp == frame->tf_rsp && |
| 919 | td->td_gd->gd_intr_nesting_level == 0) { |
| 920 | frame->tf_rip = (register_t)td->td_pcb->pcb_onfault; |
| 921 | return (0); |
| 922 | } |
| 923 | trap_fatal(frame, frame->tf_addr); |
| 924 | return (-1); |
| 925 | } |
| 926 | |
| 927 | /* |
| 928 | * NOTE: on x86_64 we have a tf_addr field in the trapframe, no |
| 929 | * kludge is needed to pass the fault address to signal handlers. |
| 930 | */ |
| 931 | p = td->td_proc; |
| 932 | if (td->td_lwp->lwp_vkernel == NULL) { |
| 933 | #ifdef DDB |
| 934 | if (bootverbose || freeze_on_seg_fault || ddb_on_seg_fault) { |
| 935 | #else |
| 936 | if (bootverbose) { |
| 937 | #endif |
| 938 | kprintf("seg-fault ft=%04x ff=%04x addr=%p rip=%p " |
| 939 | "pid=%d cpu=%d p_comm=%s\n", |
| 940 | ftype, fault_flags, |
| 941 | (void *)frame->tf_addr, |
| 942 | (void *)frame->tf_rip, |
| 943 | p->p_pid, mycpu->gd_cpuid, p->p_comm); |
| 944 | } |
| 945 | #ifdef DDB |
| 946 | while (freeze_on_seg_fault) { |
| 947 | tsleep(p, 0, "freeze", hz * 20); |
| 948 | } |
| 949 | if (ddb_on_seg_fault) |
| 950 | Debugger("ddb_on_seg_fault"); |
| 951 | #endif |
| 952 | } |
| 953 | |
| 954 | return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV); |
| 955 | } |
| 956 | |
| 957 | static void |
| 958 | trap_fatal(struct trapframe *frame, vm_offset_t eva) |
| 959 | { |
| 960 | int code, ss; |
| 961 | u_int type; |
| 962 | long rsp; |
| 963 | struct soft_segment_descriptor softseg; |
| 964 | char *msg; |
| 965 | |
| 966 | code = frame->tf_err; |
| 967 | type = frame->tf_trapno; |
| 968 | sdtossd(&gdt[IDXSEL(frame->tf_cs & 0xffff)], &softseg); |
| 969 | |
| 970 | if (type <= MAX_TRAP_MSG) |
| 971 | msg = trap_msg[type]; |
| 972 | else |
| 973 | msg = "UNKNOWN"; |
| 974 | kprintf("\n\nFatal trap %d: %s while in %s mode\n", type, msg, |
| 975 | ISPL(frame->tf_cs) == SEL_UPL ? "user" : "kernel"); |
| 976 | /* three separate prints in case of a trap on an unmapped page */ |
| 977 | kprintf("cpuid = %d; ", mycpu->gd_cpuid); |
| 978 | kprintf("lapic->id = %08x\n", lapic->id); |
| 979 | if (type == T_PAGEFLT) { |
| 980 | kprintf("fault virtual address = 0x%lx\n", eva); |
| 981 | kprintf("fault code = %s %s %s, %s\n", |
| 982 | code & PGEX_U ? "user" : "supervisor", |
| 983 | code & PGEX_W ? "write" : "read", |
| 984 | code & PGEX_I ? "instruction" : "data", |
| 985 | code & PGEX_P ? "protection violation" : "page not present"); |
| 986 | } |
| 987 | kprintf("instruction pointer = 0x%lx:0x%lx\n", |
| 988 | frame->tf_cs & 0xffff, frame->tf_rip); |
| 989 | if (ISPL(frame->tf_cs) == SEL_UPL) { |
| 990 | ss = frame->tf_ss & 0xffff; |
| 991 | rsp = frame->tf_rsp; |
| 992 | } else { |
| 993 | /* |
| 994 | * NOTE: in 64-bit mode traps push rsp/ss even if no ring |
| 995 | * change occurs. |
| 996 | */ |
| 997 | ss = GSEL(GDATA_SEL, SEL_KPL); |
| 998 | rsp = frame->tf_rsp; |
| 999 | } |
| 1000 | kprintf("stack pointer = 0x%x:0x%lx\n", ss, rsp); |
| 1001 | kprintf("frame pointer = 0x%x:0x%lx\n", ss, frame->tf_rbp); |
| 1002 | kprintf("code segment = base 0x%lx, limit 0x%lx, type 0x%x\n", |
| 1003 | softseg.ssd_base, softseg.ssd_limit, softseg.ssd_type); |
| 1004 | kprintf(" = DPL %d, pres %d, long %d, def32 %d, gran %d\n", |
| 1005 | softseg.ssd_dpl, softseg.ssd_p, softseg.ssd_long, softseg.ssd_def32, |
| 1006 | softseg.ssd_gran); |
| 1007 | kprintf("processor eflags = "); |
| 1008 | if (frame->tf_rflags & PSL_T) |
| 1009 | kprintf("trace trap, "); |
| 1010 | if (frame->tf_rflags & PSL_I) |
| 1011 | kprintf("interrupt enabled, "); |
| 1012 | if (frame->tf_rflags & PSL_NT) |
| 1013 | kprintf("nested task, "); |
| 1014 | if (frame->tf_rflags & PSL_RF) |
| 1015 | kprintf("resume, "); |
| 1016 | kprintf("IOPL = %ld\n", (frame->tf_rflags & PSL_IOPL) >> 12); |
| 1017 | kprintf("current process = "); |
| 1018 | if (curproc) { |
| 1019 | kprintf("%lu\n", |
| 1020 | (u_long)curproc->p_pid); |
| 1021 | } else { |
| 1022 | kprintf("Idle\n"); |
| 1023 | } |
| 1024 | kprintf("current thread = pri %d ", curthread->td_pri); |
| 1025 | if (curthread->td_critcount) |
| 1026 | kprintf("(CRIT)"); |
| 1027 | kprintf("\n"); |
| 1028 | |
| 1029 | #ifdef DDB |
| 1030 | if ((debugger_on_panic || db_active) && kdb_trap(type, code, frame)) |
| 1031 | return; |
| 1032 | #endif |
| 1033 | kprintf("trap number = %d\n", type); |
| 1034 | if (type <= MAX_TRAP_MSG) |
| 1035 | panic("%s", trap_msg[type]); |
| 1036 | else |
| 1037 | panic("unknown/reserved trap"); |
| 1038 | } |
| 1039 | |
| 1040 | /* |
| 1041 | * Double fault handler. Called when a fault occurs while writing |
| 1042 | * a frame for a trap/exception onto the stack. This usually occurs |
| 1043 | * when the stack overflows (such is the case with infinite recursion, |
| 1044 | * for example). |
| 1045 | */ |
| 1046 | static __inline |
| 1047 | int |
| 1048 | in_kstack_guard(register_t rptr) |
| 1049 | { |
| 1050 | thread_t td = curthread; |
| 1051 | |
| 1052 | if ((char *)rptr >= td->td_kstack && |
| 1053 | (char *)rptr < td->td_kstack + PAGE_SIZE) { |
| 1054 | return 1; |
| 1055 | } |
| 1056 | return 0; |
| 1057 | } |
| 1058 | |
| 1059 | void |
| 1060 | dblfault_handler(struct trapframe *frame) |
| 1061 | { |
| 1062 | thread_t td = curthread; |
| 1063 | |
| 1064 | if (in_kstack_guard(frame->tf_rsp) || in_kstack_guard(frame->tf_rbp)) { |
| 1065 | kprintf("DOUBLE FAULT - KERNEL STACK GUARD HIT!\n"); |
| 1066 | if (in_kstack_guard(frame->tf_rsp)) |
| 1067 | frame->tf_rsp = (register_t)(td->td_kstack + PAGE_SIZE); |
| 1068 | if (in_kstack_guard(frame->tf_rbp)) |
| 1069 | frame->tf_rbp = (register_t)(td->td_kstack + PAGE_SIZE); |
| 1070 | } else { |
| 1071 | kprintf("DOUBLE FAULT\n"); |
| 1072 | } |
| 1073 | kprintf("\nFatal double fault\n"); |
| 1074 | kprintf("rip = 0x%lx\n", frame->tf_rip); |
| 1075 | kprintf("rsp = 0x%lx\n", frame->tf_rsp); |
| 1076 | kprintf("rbp = 0x%lx\n", frame->tf_rbp); |
| 1077 | /* three separate prints in case of a trap on an unmapped page */ |
| 1078 | kprintf("cpuid = %d; ", mycpu->gd_cpuid); |
| 1079 | kprintf("lapic->id = %08x\n", lapic->id); |
| 1080 | panic("double fault"); |
| 1081 | } |
| 1082 | |
| 1083 | /* |
| 1084 | * syscall2 - MP aware system call request C handler |
| 1085 | * |
| 1086 | * A system call is essentially treated as a trap except that the |
| 1087 | * MP lock is not held on entry or return. We are responsible for |
| 1088 | * obtaining the MP lock if necessary and for handling ASTs |
| 1089 | * (e.g. a task switch) prior to return. |
| 1090 | * |
| 1091 | * MPSAFE |
| 1092 | */ |
| 1093 | void |
| 1094 | syscall2(struct trapframe *frame) |
| 1095 | { |
| 1096 | struct thread *td = curthread; |
| 1097 | struct proc *p = td->td_proc; |
| 1098 | struct lwp *lp = td->td_lwp; |
| 1099 | caddr_t params; |
| 1100 | struct sysent *callp; |
| 1101 | register_t orig_tf_rflags; |
| 1102 | int sticks; |
| 1103 | int error; |
| 1104 | int narg; |
| 1105 | #ifdef INVARIANTS |
| 1106 | int crit_count = td->td_critcount; |
| 1107 | #endif |
| 1108 | int have_mplock = 0; |
| 1109 | register_t *argp; |
| 1110 | u_int code; |
| 1111 | int reg, regcnt; |
| 1112 | union sysunion args; |
| 1113 | register_t *argsdst; |
| 1114 | |
| 1115 | mycpu->gd_cnt.v_syscall++; |
| 1116 | |
| 1117 | #ifdef DIAGNOSTIC |
| 1118 | if (ISPL(frame->tf_cs) != SEL_UPL) { |
| 1119 | get_mplock(); |
| 1120 | panic("syscall"); |
| 1121 | /* NOT REACHED */ |
| 1122 | } |
| 1123 | #endif |
| 1124 | |
| 1125 | KTR_LOG(kernentry_syscall, p->p_pid, lp->lwp_tid, |
| 1126 | frame->tf_rax); |
| 1127 | |
| 1128 | userenter(td, p); /* lazy raise our priority */ |
| 1129 | |
| 1130 | reg = 0; |
| 1131 | regcnt = 6; |
| 1132 | /* |
| 1133 | * Misc |
| 1134 | */ |
| 1135 | sticks = (int)td->td_sticks; |
| 1136 | orig_tf_rflags = frame->tf_rflags; |
| 1137 | |
| 1138 | /* |
| 1139 | * Virtual kernel intercept - if a VM context managed by a virtual |
| 1140 | * kernel issues a system call the virtual kernel handles it, not us. |
| 1141 | * Restore the virtual kernel context and return from its system |
| 1142 | * call. The current frame is copied out to the virtual kernel. |
| 1143 | */ |
| 1144 | if (lp->lwp_vkernel && lp->lwp_vkernel->ve) { |
| 1145 | vkernel_trap(lp, frame); |
| 1146 | error = EJUSTRETURN; |
| 1147 | goto out; |
| 1148 | } |
| 1149 | |
| 1150 | /* |
| 1151 | * Get the system call parameters and account for time |
| 1152 | */ |
| 1153 | KASSERT(lp->lwp_md.md_regs == frame, |
| 1154 | ("Frame mismatch %p %p", lp->lwp_md.md_regs, frame)); |
| 1155 | params = (caddr_t)frame->tf_rsp + sizeof(register_t); |
| 1156 | code = frame->tf_rax; |
| 1157 | |
| 1158 | if (p->p_sysent->sv_prepsyscall) { |
| 1159 | (*p->p_sysent->sv_prepsyscall)( |
| 1160 | frame, (int *)(&args.nosys.sysmsg + 1), |
| 1161 | &code, ¶ms); |
| 1162 | } else { |
| 1163 | if (code == SYS_syscall || code == SYS___syscall) { |
| 1164 | code = frame->tf_rdi; |
| 1165 | reg++; |
| 1166 | regcnt--; |
| 1167 | } |
| 1168 | } |
| 1169 | |
| 1170 | if (p->p_sysent->sv_mask) |
| 1171 | code &= p->p_sysent->sv_mask; |
| 1172 | |
| 1173 | if (code >= p->p_sysent->sv_size) |
| 1174 | callp = &p->p_sysent->sv_table[0]; |
| 1175 | else |
| 1176 | callp = &p->p_sysent->sv_table[code]; |
| 1177 | |
| 1178 | narg = callp->sy_narg & SYF_ARGMASK; |
| 1179 | |
| 1180 | /* |
| 1181 | * On x86_64 we get up to six arguments in registers. The rest are |
| 1182 | * on the stack. The first six members of 'struct trapframe' happen |
| 1183 | * to be the registers used to pass arguments, in exactly the right |
| 1184 | * order. |
| 1185 | */ |
| 1186 | argp = &frame->tf_rdi; |
| 1187 | argp += reg; |
| 1188 | argsdst = (register_t *)(&args.nosys.sysmsg + 1); |
| 1189 | /* |
| 1190 | * JG can we overflow the space pointed to by 'argsdst' |
| 1191 | * either with 'bcopy' or with 'copyin'? |
| 1192 | */ |
| 1193 | bcopy(argp, argsdst, sizeof(register_t) * regcnt); |
| 1194 | /* |
| 1195 | * copyin is MP aware, but the tracing code is not |
| 1196 | */ |
| 1197 | if (narg > regcnt) { |
| 1198 | KASSERT(params != NULL, ("copyin args with no params!")); |
| 1199 | error = copyin(params, &argsdst[regcnt], |
| 1200 | (narg - regcnt) * sizeof(register_t)); |
| 1201 | if (error) { |
| 1202 | #ifdef KTRACE |
| 1203 | if (KTRPOINT(td, KTR_SYSCALL)) { |
| 1204 | MAKEMPSAFE(have_mplock); |
| 1205 | |
| 1206 | ktrsyscall(lp, code, narg, |
| 1207 | (void *)(&args.nosys.sysmsg + 1)); |
| 1208 | } |
| 1209 | #endif |
| 1210 | goto bad; |
| 1211 | } |
| 1212 | } |
| 1213 | |
| 1214 | #ifdef KTRACE |
| 1215 | if (KTRPOINT(td, KTR_SYSCALL)) { |
| 1216 | MAKEMPSAFE(have_mplock); |
| 1217 | ktrsyscall(lp, code, narg, (void *)(&args.nosys.sysmsg + 1)); |
| 1218 | } |
| 1219 | #endif |
| 1220 | |
| 1221 | /* |
| 1222 | * Default return value is 0 (will be copied to %rax). Double-value |
| 1223 | * returns use %rax and %rdx. %rdx is left unchanged for system |
| 1224 | * calls which return only one result. |
| 1225 | */ |
| 1226 | args.sysmsg_fds[0] = 0; |
| 1227 | args.sysmsg_fds[1] = frame->tf_rdx; |
| 1228 | |
| 1229 | /* |
| 1230 | * The syscall might manipulate the trap frame. If it does it |
| 1231 | * will probably return EJUSTRETURN. |
| 1232 | */ |
| 1233 | args.sysmsg_frame = frame; |
| 1234 | |
| 1235 | STOPEVENT(p, S_SCE, narg); /* MP aware */ |
| 1236 | |
| 1237 | /* |
| 1238 | * NOTE: All system calls run MPSAFE now. The system call itself |
| 1239 | * is responsible for getting the MP lock. |
| 1240 | */ |
| 1241 | #ifdef SYSCALL_DEBUG |
| 1242 | uint64_t tscval = rdtsc(); |
| 1243 | #endif |
| 1244 | error = (*callp->sy_call)(&args); |
| 1245 | #ifdef SYSCALL_DEBUG |
| 1246 | tscval = rdtsc() - tscval; |
| 1247 | tscval = tscval * 1000000 / tsc_frequency; |
| 1248 | if (SysCallsWorstCase[code] < tscval) |
| 1249 | SysCallsWorstCase[code] = tscval; |
| 1250 | #endif |
| 1251 | |
| 1252 | out: |
| 1253 | /* |
| 1254 | * MP SAFE (we may or may not have the MP lock at this point) |
| 1255 | */ |
| 1256 | //kprintf("SYSMSG %d ", error); |
| 1257 | switch (error) { |
| 1258 | case 0: |
| 1259 | /* |
| 1260 | * Reinitialize proc pointer `p' as it may be different |
| 1261 | * if this is a child returning from fork syscall. |
| 1262 | */ |
| 1263 | p = curproc; |
| 1264 | lp = curthread->td_lwp; |
| 1265 | frame->tf_rax = args.sysmsg_fds[0]; |
| 1266 | frame->tf_rdx = args.sysmsg_fds[1]; |
| 1267 | frame->tf_rflags &= ~PSL_C; |
| 1268 | break; |
| 1269 | case ERESTART: |
| 1270 | /* |
| 1271 | * Reconstruct pc, we know that 'syscall' is 2 bytes. |
| 1272 | * We have to do a full context restore so that %r10 |
| 1273 | * (which was holding the value of %rcx) is restored for |
| 1274 | * the next iteration. |
| 1275 | */ |
| 1276 | if (frame->tf_err != 0 && frame->tf_err != 2) |
| 1277 | kprintf("lp %s:%d frame->tf_err is weird %ld\n", |
| 1278 | td->td_comm, lp->lwp_proc->p_pid, frame->tf_err); |
| 1279 | frame->tf_rip -= frame->tf_err; |
| 1280 | frame->tf_r10 = frame->tf_rcx; |
| 1281 | break; |
| 1282 | case EJUSTRETURN: |
| 1283 | break; |
| 1284 | case EASYNC: |
| 1285 | panic("Unexpected EASYNC return value (for now)"); |
| 1286 | default: |
| 1287 | bad: |
| 1288 | if (p->p_sysent->sv_errsize) { |
| 1289 | if (error >= p->p_sysent->sv_errsize) |
| 1290 | error = -1; /* XXX */ |
| 1291 | else |
| 1292 | error = p->p_sysent->sv_errtbl[error]; |
| 1293 | } |
| 1294 | frame->tf_rax = error; |
| 1295 | frame->tf_rflags |= PSL_C; |
| 1296 | break; |
| 1297 | } |
| 1298 | |
| 1299 | /* |
| 1300 | * Traced syscall. trapsignal() is not MP aware. |
| 1301 | */ |
| 1302 | if (orig_tf_rflags & PSL_T) { |
| 1303 | MAKEMPSAFE(have_mplock); |
| 1304 | frame->tf_rflags &= ~PSL_T; |
| 1305 | trapsignal(lp, SIGTRAP, TRAP_TRACE); |
| 1306 | } |
| 1307 | |
| 1308 | /* |
| 1309 | * Handle reschedule and other end-of-syscall issues |
| 1310 | */ |
| 1311 | userret(lp, frame, sticks); |
| 1312 | |
| 1313 | #ifdef KTRACE |
| 1314 | if (KTRPOINT(td, KTR_SYSRET)) { |
| 1315 | MAKEMPSAFE(have_mplock); |
| 1316 | ktrsysret(lp, code, error, args.sysmsg_result); |
| 1317 | } |
| 1318 | #endif |
| 1319 | |
| 1320 | /* |
| 1321 | * This works because errno is findable through the |
| 1322 | * register set. If we ever support an emulation where this |
| 1323 | * is not the case, this code will need to be revisited. |
| 1324 | */ |
| 1325 | STOPEVENT(p, S_SCX, code); |
| 1326 | |
| 1327 | userexit(lp); |
| 1328 | /* |
| 1329 | * Release the MP lock if we had to get it |
| 1330 | */ |
| 1331 | if (have_mplock) |
| 1332 | rel_mplock(); |
| 1333 | KTR_LOG(kernentry_syscall_ret, p->p_pid, lp->lwp_tid, error); |
| 1334 | #ifdef INVARIANTS |
| 1335 | KASSERT(crit_count == td->td_critcount, |
| 1336 | ("syscall: critical section count mismatch! %d/%d", |
| 1337 | crit_count, td->td_pri)); |
| 1338 | KASSERT(&td->td_toks_base == td->td_toks_stop, |
| 1339 | ("syscall: extra tokens held after trap! %ld", |
| 1340 | td->td_toks_stop - &td->td_toks_base)); |
| 1341 | #endif |
| 1342 | } |
| 1343 | |
| 1344 | /* |
| 1345 | * NOTE: mplock not held at any point |
| 1346 | */ |
| 1347 | void |
| 1348 | fork_return(struct lwp *lp, struct trapframe *frame) |
| 1349 | { |
| 1350 | frame->tf_rax = 0; /* Child returns zero */ |
| 1351 | frame->tf_rflags &= ~PSL_C; /* success */ |
| 1352 | frame->tf_rdx = 1; |
| 1353 | |
| 1354 | generic_lwp_return(lp, frame); |
| 1355 | KTR_LOG(kernentry_fork_ret, lp->lwp_proc->p_pid, lp->lwp_tid); |
| 1356 | } |
| 1357 | |
| 1358 | /* |
| 1359 | * Simplified back end of syscall(), used when returning from fork() |
| 1360 | * directly into user mode. |
| 1361 | * |
| 1362 | * This code will return back into the fork trampoline code which then |
| 1363 | * runs doreti. |
| 1364 | * |
| 1365 | * NOTE: The mplock is not held at any point. |
| 1366 | */ |
| 1367 | void |
| 1368 | generic_lwp_return(struct lwp *lp, struct trapframe *frame) |
| 1369 | { |
| 1370 | struct proc *p = lp->lwp_proc; |
| 1371 | |
| 1372 | /* |
| 1373 | * Newly forked processes are given a kernel priority. We have to |
| 1374 | * adjust the priority to a normal user priority and fake entry |
| 1375 | * into the kernel (call userenter()) to install a passive release |
| 1376 | * function just in case userret() decides to stop the process. This |
| 1377 | * can occur when ^Z races a fork. If we do not install the passive |
| 1378 | * release function the current process designation will not be |
| 1379 | * released when the thread goes to sleep. |
| 1380 | */ |
| 1381 | lwkt_setpri_self(TDPRI_USER_NORM); |
| 1382 | userenter(lp->lwp_thread, p); |
| 1383 | userret(lp, frame, 0); |
| 1384 | #ifdef KTRACE |
| 1385 | if (KTRPOINT(lp->lwp_thread, KTR_SYSRET)) |
| 1386 | ktrsysret(lp, SYS_fork, 0, 0); |
| 1387 | #endif |
| 1388 | lp->lwp_flags |= LWP_PASSIVE_ACQ; |
| 1389 | userexit(lp); |
| 1390 | lp->lwp_flags &= ~LWP_PASSIVE_ACQ; |
| 1391 | } |
| 1392 | |
| 1393 | /* |
| 1394 | * If PGEX_FPFAULT is set then set FP_VIRTFP in the PCB to force a T_DNA |
| 1395 | * fault (which is then passed back to the virtual kernel) if an attempt is |
| 1396 | * made to use the FP unit. |
| 1397 | * |
| 1398 | * XXX this is a fairly big hack. |
| 1399 | */ |
| 1400 | void |
| 1401 | set_vkernel_fp(struct trapframe *frame) |
| 1402 | { |
| 1403 | struct thread *td = curthread; |
| 1404 | |
| 1405 | if (frame->tf_xflags & PGEX_FPFAULT) { |
| 1406 | td->td_pcb->pcb_flags |= FP_VIRTFP; |
| 1407 | if (mdcpu->gd_npxthread == td) |
| 1408 | npxexit(); |
| 1409 | } else { |
| 1410 | td->td_pcb->pcb_flags &= ~FP_VIRTFP; |
| 1411 | } |
| 1412 | } |
| 1413 | |
| 1414 | /* |
| 1415 | * Called from vkernel_trap() to fixup the vkernel's syscall |
| 1416 | * frame for vmspace_ctl() return. |
| 1417 | */ |
| 1418 | void |
| 1419 | cpu_vkernel_trap(struct trapframe *frame, int error) |
| 1420 | { |
| 1421 | frame->tf_rax = error; |
| 1422 | if (error) |
| 1423 | frame->tf_rflags |= PSL_C; |
| 1424 | else |
| 1425 | frame->tf_rflags &= ~PSL_C; |
| 1426 | } |