kernel - Major signal path adjustments to fix races, tsleep race fixes, +more
[dragonfly.git] / sys / platform / pc64 / x86_64 / trap.c
CommitLineData
d7f50089 1/*-
d7f50089
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2 * Copyright (c) 1990, 1993
3 * The Regents of the University of California. All rights reserved.
c8fe38ae
MD
4 * Copyright (C) 1994, David Greenman
5 * Copyright (c) 2008 The DragonFly Project.
6 * Copyright (c) 2008 Jordan Gordeev.
d7f50089
YY
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 *
c8fe38ae 39 * from: @(#)trap.c 7.4 (Berkeley) 5/13/91
d7f50089 40 * $FreeBSD: src/sys/i386/i386/trap.c,v 1.147.2.11 2003/02/27 19:09:59 luoqi Exp $
d7f50089
YY
41 */
42
c8fe38ae 43/*
b2b3ffcd 44 * x86_64 Trap and System call handling
c8fe38ae
MD
45 */
46
775ce2da
SW
47#include "use_isa.h"
48
c8fe38ae
MD
49#include "opt_ddb.h"
50#include "opt_ktrace.h"
d7f50089
YY
51
52#include <machine/frame.h>
c8fe38ae
MD
53#include <sys/param.h>
54#include <sys/systm.h>
55#include <sys/kernel.h>
5ea440eb 56#include <sys/kerneldump.h>
c8fe38ae
MD
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>
46d4e165 80#include <machine/smp.h>
c8fe38ae 81#include <machine/thread.h>
d2d8515b 82#include <machine/clock.h>
c8fe38ae
MD
83#include <machine/vmparam.h>
84#include <machine/md_var.h>
57a9c56b 85#include <machine_base/isa/isa_intr.h>
83c8d73e 86#include <machine_base/apic/lapic.h>
c8fe38ae
MD
87
88#include <ddb/ddb.h>
684a93c4 89
46d4e165 90#include <sys/thread2.h>
684a93c4 91#include <sys/mplock2.h>
c8fe38ae
MD
92
93#ifdef SMP
94
95#define MAKEMPSAFE(have_mplock) \
96 if (have_mplock == 0) { \
97 get_mplock(); \
98 have_mplock = 1; \
99 }
100
101#else
102
103#define MAKEMPSAFE(have_mplock)
104
105#endif
106
107extern void trap(struct trapframe *frame);
c8fe38ae
MD
108
109static int trap_pfault(struct trapframe *, int);
110static void trap_fatal(struct trapframe *, vm_offset_t);
111void dblfault_handler(struct trapframe *frame);
112
c8fe38ae
MD
113#define MAX_TRAP_MSG 30
114static 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
149static int ddb_on_nmi = 1;
150SYSCTL_INT(_machdep, OID_AUTO, ddb_on_nmi, CTLFLAG_RW,
151 &ddb_on_nmi, 0, "Go to DDB on NMI");
2883d2d8
MD
152static int ddb_on_seg_fault = 0;
153SYSCTL_INT(_machdep, OID_AUTO, ddb_on_seg_fault, CTLFLAG_RW,
154 &ddb_on_seg_fault, 0, "Go to DDB on user seg-fault");
d2d8515b
MD
155static int freeze_on_seg_fault = 0;
156SYSCTL_INT(_machdep, OID_AUTO, freeze_on_seg_fault, CTLFLAG_RW,
157 &freeze_on_seg_fault, 0, "Go to DDB on user seg-fault");
c8fe38ae
MD
158#endif
159static int panic_on_nmi = 1;
160SYSCTL_INT(_machdep, OID_AUTO, panic_on_nmi, CTLFLAG_RW,
161 &panic_on_nmi, 0, "Panic on NMI");
162static int fast_release;
163SYSCTL_INT(_machdep, OID_AUTO, fast_release, CTLFLAG_RW,
164 &fast_release, 0, "Passive Release was optimal");
165static int slow_release;
166SYSCTL_INT(_machdep, OID_AUTO, slow_release, CTLFLAG_RW,
167 &slow_release, 0, "Passive Release was nonoptimal");
c8fe38ae 168
c8fe38ae 169/*
d2d8515b
MD
170 * System call debugging records the worst-case system call
171 * overhead (inclusive of blocking), but may be inaccurate.
172 */
173/*#define SYSCALL_DEBUG*/
174#ifdef SYSCALL_DEBUG
175uint64_t SysCallsWorstCase[SYS_MAXSYSCALL];
176#endif
177
178/*
7bd858e5 179 * Passively intercepts the thread switch function to increase
c8fe38ae
MD
180 * the thread priority from a user priority to a kernel priority, reducing
181 * syscall and trap overhead for the case where no switch occurs.
7bd858e5 182 *
d86a23e0 183 * Synchronizes td_ucred with p_ucred. This is used by system calls,
7bd858e5
MD
184 * signal handling, faults, AST traps, and anything else that enters the
185 * kernel from userland and provides the kernel with a stable read-only
186 * copy of the process ucred.
c8fe38ae 187 */
c8fe38ae 188static __inline void
d86a23e0 189userenter(struct thread *curtd, struct proc *curp)
c8fe38ae 190{
7bd858e5
MD
191 struct ucred *ocred;
192 struct ucred *ncred;
193
3824f392 194 curtd->td_release = lwkt_passive_release;
7bd858e5 195
d86a23e0
MD
196 if (curtd->td_ucred != curp->p_ucred) {
197 ncred = crhold(curp->p_ucred);
198 ocred = curtd->td_ucred;
199 curtd->td_ucred = ncred;
7bd858e5
MD
200 if (ocred)
201 crfree(ocred);
202 }
4643740a
MD
203
204 /*
205 * Debugging, remove top two user stack pages to catch kernel faults
206 */
207 if (freeze_on_seg_fault > 1 && curtd->td_lwp) {
208 pmap_remove(vmspace_pmap(curtd->td_lwp->lwp_vmspace),
209 0x00007FFFFFFFD000LU,
210 0x0000800000000000LU);
211 }
c8fe38ae
MD
212}
213
214/*
215 * Handle signals, upcalls, profiling, and other AST's and/or tasks that
216 * must be completed before we can return to or try to return to userland.
217 *
218 * Note that td_sticks is a 64 bit quantity, but there's no point doing 64
219 * arithmatic on the delta calculation so the absolute tick values are
220 * truncated to an integer.
221 */
222static void
223userret(struct lwp *lp, struct trapframe *frame, int sticks)
224{
225 struct proc *p = lp->lwp_proc;
226 int sig;
227
228 /*
229 * Charge system time if profiling. Note: times are in microseconds.
230 * This may do a copyout and block, so do it first even though it
231 * means some system time will be charged as user time.
232 */
4643740a 233 if (p->p_flags & P_PROFIL) {
c8fe38ae
MD
234 addupc_task(p, frame->tf_rip,
235 (u_int)((int)lp->lwp_thread->td_sticks - sticks));
236 }
237
238recheck:
239 /*
240 * If the jungle wants us dead, so be it.
241 */
4643740a 242 if (lp->lwp_mpflags & LWP_MP_WEXIT) {
b5c4d81f 243 lwkt_gettoken(&p->p_token);
c8fe38ae 244 lwp_exit(0);
b5c4d81f 245 lwkt_reltoken(&p->p_token); /* NOT REACHED */
c8fe38ae
MD
246 }
247
248 /*
249 * Block here if we are in a stopped state.
250 */
5ea440eb 251 if (p->p_stat == SSTOP || dump_stop_usertds) {
4643740a 252 lwkt_gettoken(&p->p_token);
c8fe38ae 253 tstop();
4643740a 254 lwkt_reltoken(&p->p_token);
c8fe38ae
MD
255 goto recheck;
256 }
257
258 /*
259 * Post any pending upcalls. If running a virtual kernel be sure
260 * to restore the virtual kernel's vmspace before posting the upcall.
261 */
4643740a 262 if (p->p_flags & (P_SIGVTALRM | P_SIGPROF | P_UPCALLPEND)) {
fc509460 263 lwkt_gettoken(&p->p_token);
4643740a
MD
264 if (p->p_flags & P_SIGVTALRM) {
265 p->p_flags &= ~P_SIGVTALRM;
898e34b3
MD
266 ksignal(p, SIGVTALRM);
267 }
4643740a
MD
268 if (p->p_flags & P_SIGPROF) {
269 p->p_flags &= ~P_SIGPROF;
898e34b3
MD
270 ksignal(p, SIGPROF);
271 }
4643740a
MD
272 if (p->p_flags & P_UPCALLPEND) {
273 p->p_flags &= ~P_UPCALLPEND;
898e34b3
MD
274 postupcall(lp);
275 }
fc509460 276 lwkt_reltoken(&p->p_token);
c8fe38ae
MD
277 goto recheck;
278 }
279
280 /*
281 * Post any pending signals. If running a virtual kernel be sure
282 * to restore the virtual kernel's vmspace before posting the signal.
2883d2d8
MD
283 *
284 * WARNING! postsig() can exit and not return.
c8fe38ae 285 */
e473f776 286 if ((sig = CURSIG_TRACE(lp)) != 0) {
fc509460 287 lwkt_gettoken(&p->p_token);
c8fe38ae 288 postsig(sig);
fc509460 289 lwkt_reltoken(&p->p_token);
c8fe38ae
MD
290 goto recheck;
291 }
292
293 /*
294 * block here if we are swapped out, but still process signals
295 * (such as SIGKILL). proc0 (the swapin scheduler) is already
296 * aware of our situation, we do not have to wake it up.
297 */
4643740a 298 if (p->p_flags & P_SWAPPEDOUT) {
616516c8 299 lwkt_gettoken(&p->p_token);
c8fe38ae 300 get_mplock();
4643740a 301 p->p_flags |= P_SWAPWAIT;
c8fe38ae 302 swapin_request();
4643740a 303 if (p->p_flags & P_SWAPWAIT)
c8fe38ae 304 tsleep(p, PCATCH, "SWOUT", 0);
4643740a 305 p->p_flags &= ~P_SWAPWAIT;
c8fe38ae 306 rel_mplock();
616516c8 307 lwkt_reltoken(&p->p_token);
c8fe38ae
MD
308 goto recheck;
309 }
310
311 /*
312 * Make sure postsig() handled request to restore old signal mask after
313 * running signal handler.
314 */
4643740a 315 KKASSERT((lp->lwp_flags & LWP_OLDMASK) == 0);
c8fe38ae
MD
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 */
323static __inline void
324userexit(struct lwp *lp)
325{
326 struct thread *td = lp->lwp_thread;
973c11b9 327/* globaldata_t gd = td->td_gd;*/
c8fe38ae 328
c8fe38ae 329 /*
89ffa1cf
SS
330 * Handle stop requests at kernel priority. Any requests queued
331 * after this loop will generate another AST.
c8fe38ae 332 */
89ffa1cf 333 while (lp->lwp_proc->p_stat == SSTOP) {
4643740a 334 lwkt_gettoken(&lp->lwp_proc->p_token);
89ffa1cf 335 tstop();
4643740a 336 lwkt_reltoken(&lp->lwp_proc->p_token);
c8fe38ae
MD
337 }
338
339 /*
c8fe38ae
MD
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 */
3824f392 344 lwkt_passive_recover(td);
89ffa1cf
SS
345
346 /*
347 * Become the current user scheduled process if we aren't already,
348 * and deal with reschedule requests and other factors.
349 */
350 lp->lwp_proc->p_usched->acquire_curproc(lp);
351 /* WARNING: we may have migrated cpu's */
352 /* gd = td->td_gd; */
c8fe38ae
MD
353}
354
0855a2af
JG
355#if !defined(KTR_KERNENTRY)
356#define KTR_KERNENTRY KTR_ALL
357#endif
358KTR_INFO_MASTER(kernentry);
359KTR_INFO(KTR_KERNENTRY, kernentry, trap, 0, "STR",
360 sizeof(long) + sizeof(long) + sizeof(long) + sizeof(vm_offset_t));
361KTR_INFO(KTR_KERNENTRY, kernentry, trap_ret, 0, "STR",
362 sizeof(long) + sizeof(long));
363KTR_INFO(KTR_KERNENTRY, kernentry, syscall, 0, "STR",
364 sizeof(long) + sizeof(long) + sizeof(long));
365KTR_INFO(KTR_KERNENTRY, kernentry, syscall_ret, 0, "STR",
366 sizeof(long) + sizeof(long) + sizeof(long));
367KTR_INFO(KTR_KERNENTRY, kernentry, fork_ret, 0, "STR",
368 sizeof(long) + sizeof(long));
369
c8fe38ae
MD
370/*
371 * Exception, fault, and trap interface to the kernel.
372 * This common code is called from assembly language IDT gate entry
373 * routines that prepare a suitable stack frame, and restore this
374 * frame after the exception has been processed.
375 *
376 * This function is also called from doreti in an interlock to handle ASTs.
377 * For example: hardwareint->INTROUTINE->(set ast)->doreti->trap
378 *
379 * NOTE! We have to retrieve the fault address prior to obtaining the
380 * MP lock because get_mplock() may switch out. YYY cr2 really ought
381 * to be retrieved by the assembly code, not here.
382 *
383 * XXX gd_trap_nesting_level currently prevents lwkt_switch() from panicing
384 * if an attempt is made to switch from a fast interrupt or IPI. This is
385 * necessary to properly take fatal kernel traps on SMP machines if
386 * get_mplock() has to block.
387 */
388
389void
390trap(struct trapframe *frame)
391{
392 struct globaldata *gd = mycpu;
393 struct thread *td = gd->gd_curthread;
394 struct lwp *lp = td->td_lwp;
395 struct proc *p;
396 int sticks = 0;
397 int i = 0, ucode = 0, type, code;
398#ifdef SMP
399 int have_mplock = 0;
400#endif
401#ifdef INVARIANTS
f9235b6d 402 int crit_count = td->td_critcount;
3933a3ab 403 lwkt_tokref_t curstop = td->td_toks_stop;
c8fe38ae
MD
404#endif
405 vm_offset_t eva;
406
407 p = td->td_proc;
f2081646 408 clear_quickret();
c8fe38ae 409
c8fe38ae 410#ifdef DDB
bfb6d329
AH
411 /*
412 * We need to allow T_DNA faults when the debugger is active since
2921c824 413 * some dumping paths do large bcopy() which use the floating
bfb6d329
AH
414 * point registers for faster copying.
415 */
5ea440eb 416 if (db_active && frame->tf_trapno != T_DNA) {
c8fe38ae
MD
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
c8fe38ae
MD
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
d86a23e0 464 userenter(td, p);
c8fe38ae
MD
465
466 sticks = (int)td->td_sticks;
d1368d1a
MD
467 KASSERT(lp->lwp_md.md_regs == frame,
468 ("Frame mismatch %p %p", lp->lwp_md.md_regs, frame));
c8fe38ae
MD
469
470 switch (type) {
471 case T_PRIVINFLT: /* privileged instruction fault */
472 ucode = ILL_PRVOPC;
473 i = SIGILL;
474 break;
475
476 case T_BPTFLT: /* bpt instruction fault */
477 case T_TRCTRAP: /* trace trap */
478 frame->tf_rflags &= ~PSL_T;
f2642d5a 479 ucode = TRAP_TRACE;
c8fe38ae
MD
480 i = SIGTRAP;
481 break;
482
483 case T_ARITHTRAP: /* arithmetic trap */
484 ucode = code;
485 i = SIGFPE;
486#if 0
487#if JG
488 ucode = fputrap();
489#else
490 ucode = code;
491#endif
492 i = SIGFPE;
493#endif
494 break;
495
496 case T_ASTFLT: /* Allow process switch */
497 mycpu->gd_cnt.v_soft++;
498 if (mycpu->gd_reqflags & RQF_AST_OWEUPC) {
2a418930
MD
499 atomic_clear_int(&mycpu->gd_reqflags,
500 RQF_AST_OWEUPC);
c8fe38ae
MD
501 addupc_task(p, p->p_prof.pr_addr,
502 p->p_prof.pr_ticks);
503 }
504 goto out;
505
506 case T_PROTFLT: /* general protection fault */
f2642d5a
AH
507 i = SIGBUS;
508 ucode = BUS_OBJERR;
509 break;
c8fe38ae 510 case T_SEGNPFLT: /* segment not present fault */
f2642d5a
AH
511 i = SIGBUS;
512 ucode = BUS_ADRERR;
513 break;
c8fe38ae
MD
514 case T_TSSFLT: /* invalid TSS fault */
515 case T_DOUBLEFLT: /* double fault */
f2642d5a
AH
516 i = SIGBUS;
517 ucode = BUS_OBJERR;
c8fe38ae 518 default:
f2642d5a
AH
519#if 0
520 ucode = code + BUS_SEGM_FAULT ; /* XXX: ???*/
521#endif
522 ucode = BUS_OBJERR;
c8fe38ae
MD
523 i = SIGBUS;
524 break;
525
526 case T_PAGEFLT: /* page fault */
c8fe38ae 527 i = trap_pfault(frame, TRUE);
d2d8515b 528 if (frame->tf_rip == 0) {
973c11b9 529 kprintf("T_PAGEFLT: Warning %%rip == 0!\n");
d2d8515b
MD
530 while (freeze_on_seg_fault) {
531 tsleep(p, 0, "freeze", hz * 20);
532 }
533 }
c8fe38ae
MD
534 if (i == -1)
535 goto out;
536 if (i == 0)
537 goto out;
538
f2642d5a 539#if 0
c8fe38ae 540 ucode = T_PAGEFLT;
f2642d5a
AH
541#endif
542 if (i == SIGSEGV)
543 ucode = SEGV_MAPERR;
544 else
545 ucode = BUS_ADRERR;
c8fe38ae
MD
546 break;
547
548 case T_DIVIDE: /* integer divide fault */
549 ucode = FPE_INTDIV;
550 i = SIGFPE;
551 break;
552
775ce2da 553#if NISA > 0
c8fe38ae
MD
554 case T_NMI:
555 MAKEMPSAFE(have_mplock);
556 /* machine/parity/power fail/"kitchen sink" faults */
557 if (isa_nmi(code) == 0) {
558#ifdef DDB
559 /*
560 * NMI can be hooked up to a pushbutton
561 * for debugging.
562 */
563 if (ddb_on_nmi) {
564 kprintf ("NMI ... going to debugger\n");
565 kdb_trap(type, 0, frame);
566 }
567#endif /* DDB */
568 goto out2;
569 } else if (panic_on_nmi)
570 panic("NMI indicates hardware failure");
571 break;
775ce2da 572#endif /* NISA > 0 */
c8fe38ae
MD
573
574 case T_OFLOW: /* integer overflow fault */
575 ucode = FPE_INTOVF;
576 i = SIGFPE;
577 break;
578
579 case T_BOUND: /* bounds check fault */
580 ucode = FPE_FLTSUB;
581 i = SIGFPE;
582 break;
583
584 case T_DNA:
585 /*
586 * Virtual kernel intercept - pass the DNA exception
587 * to the virtual kernel if it asked to handle it.
588 * This occurs when the virtual kernel is holding
589 * onto the FP context for a different emulated
590 * process then the one currently running.
591 *
592 * We must still call npxdna() since we may have
593 * saved FP state that the virtual kernel needs
594 * to hand over to a different emulated process.
595 */
596 if (lp->lwp_vkernel && lp->lwp_vkernel->ve &&
597 (td->td_pcb->pcb_flags & FP_VIRTFP)
598 ) {
599 npxdna();
600 break;
601 }
602
603 /*
604 * The kernel may have switched out the FP unit's
605 * state, causing the user process to take a fault
606 * when it tries to use the FP unit. Restore the
607 * state here
608 */
609 if (npxdna())
610 goto out;
611 i = SIGFPE;
612 ucode = FPE_FPU_NP_TRAP;
613 break;
614
615 case T_FPOPFLT: /* FPU operand fetch fault */
f2642d5a 616 ucode = ILL_COPROC;
c8fe38ae
MD
617 i = SIGILL;
618 break;
619
620 case T_XMMFLT: /* SIMD floating-point exception */
621 ucode = 0; /* XXX */
622 i = SIGFPE;
623 break;
624 }
625 } else {
626 /* kernel trap */
627
628 switch (type) {
629 case T_PAGEFLT: /* page fault */
c8fe38ae
MD
630 trap_pfault(frame, FALSE);
631 goto out2;
632
633 case T_DNA:
634 /*
635 * The kernel is apparently using fpu for copying.
636 * XXX this should be fatal unless the kernel has
637 * registered such use.
638 */
639 if (npxdna())
640 goto out2;
641 break;
642
643 case T_STKFLT: /* stack fault */
644 break;
645
646 case T_PROTFLT: /* general protection fault */
647 case T_SEGNPFLT: /* segment not present fault */
648 /*
649 * Invalid segment selectors and out of bounds
650 * %rip's and %rsp's can be set up in user mode.
651 * This causes a fault in kernel mode when the
652 * kernel tries to return to user mode. We want
653 * to get this fault so that we can fix the
654 * problem here and not have to check all the
655 * selectors and pointers when the user changes
656 * them.
657 */
c8fe38ae
MD
658 if (mycpu->gd_intr_nesting_level == 0) {
659 if (td->td_pcb->pcb_onfault) {
660 frame->tf_rip = (register_t)
661 td->td_pcb->pcb_onfault;
662 goto out2;
663 }
89ffa1cf
SS
664 if (frame->tf_rip == (long)doreti_iret) {
665 frame->tf_rip = (long)doreti_iret_fault;
666 goto out2;
667 }
c8fe38ae
MD
668 }
669 break;
670
671 case T_TSSFLT:
672 /*
673 * PSL_NT can be set in user mode and isn't cleared
674 * automatically when the kernel is entered. This
675 * causes a TSS fault when the kernel attempts to
676 * `iret' because the TSS link is uninitialized. We
677 * want to get this fault so that we can fix the
678 * problem here and not every time the kernel is
679 * entered.
680 */
681 if (frame->tf_rflags & PSL_NT) {
682 frame->tf_rflags &= ~PSL_NT;
683 goto out2;
684 }
685 break;
686
687 case T_TRCTRAP: /* trace trap */
688#if 0
689 if (frame->tf_rip == (int)IDTVEC(syscall)) {
690 /*
691 * We've just entered system mode via the
692 * syscall lcall. Continue single stepping
693 * silently until the syscall handler has
694 * saved the flags.
695 */
696 goto out2;
697 }
698 if (frame->tf_rip == (int)IDTVEC(syscall) + 1) {
699 /*
700 * The syscall handler has now saved the
701 * flags. Stop single stepping it.
702 */
703 frame->tf_rflags &= ~PSL_T;
704 goto out2;
705 }
706#endif
707
708 /*
709 * Ignore debug register trace traps due to
710 * accesses in the user's address space, which
711 * can happen under several conditions such as
712 * if a user sets a watchpoint on a buffer and
713 * then passes that buffer to a system call.
714 * We still want to get TRCTRAPS for addresses
715 * in kernel space because that is useful when
716 * debugging the kernel.
717 */
718#if JG
719 if (user_dbreg_trap()) {
720 /*
721 * Reset breakpoint bits because the
722 * processor doesn't
723 */
724 /* XXX check upper bits here */
725 load_dr6(rdr6() & 0xfffffff0);
726 goto out2;
727 }
728#endif
729 /*
730 * FALLTHROUGH (TRCTRAP kernel mode, kernel address)
731 */
732 case T_BPTFLT:
733 /*
734 * If DDB is enabled, let it handle the debugger trap.
735 * Otherwise, debugger traps "can't happen".
736 */
f2642d5a 737 ucode = TRAP_BRKPT;
c8fe38ae
MD
738#ifdef DDB
739 MAKEMPSAFE(have_mplock);
740 if (kdb_trap(type, 0, frame))
741 goto out2;
742#endif
743 break;
744
775ce2da 745#if NISA > 0
c8fe38ae
MD
746 case T_NMI:
747 MAKEMPSAFE(have_mplock);
748 /* machine/parity/power fail/"kitchen sink" faults */
c8fe38ae
MD
749 if (isa_nmi(code) == 0) {
750#ifdef DDB
751 /*
752 * NMI can be hooked up to a pushbutton
753 * for debugging.
754 */
755 if (ddb_on_nmi) {
756 kprintf ("NMI ... going to debugger\n");
757 kdb_trap(type, 0, frame);
758 }
759#endif /* DDB */
760 goto out2;
761 } else if (panic_on_nmi == 0)
762 goto out2;
763 /* FALL THROUGH */
764#endif /* NISA > 0 */
765 }
766 MAKEMPSAFE(have_mplock);
767 trap_fatal(frame, 0);
73e24181
MD
768 goto out2;
769 }
770
771 /*
772 * Virtual kernel intercept - if the fault is directly related to a
773 * VM context managed by a virtual kernel then let the virtual kernel
774 * handle it.
775 */
776 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) {
777 vkernel_trap(lp, frame);
c8fe38ae
MD
778 goto out;
779 }
780
781 /*
782 * Translate fault for emulators (e.g. Linux)
783 */
784 if (*p->p_sysent->sv_transtrap)
785 i = (*p->p_sysent->sv_transtrap)(i, type);
786
787 MAKEMPSAFE(have_mplock);
788 trapsignal(lp, i, ucode);
789
790#ifdef DEBUG
791 if (type <= MAX_TRAP_MSG) {
792 uprintf("fatal process exception: %s",
793 trap_msg[type]);
794 if ((type == T_PAGEFLT) || (type == T_PROTFLT))
795 uprintf(", fault VA = 0x%lx", frame->tf_addr);
796 uprintf("\n");
797 }
798#endif
799
800out:
c8fe38ae
MD
801 userret(lp, frame, sticks);
802 userexit(lp);
803out2: ;
804#ifdef SMP
805 if (have_mplock)
806 rel_mplock();
807#endif
808 if (p != NULL && lp != NULL)
809 KTR_LOG(kernentry_trap_ret, p->p_pid, lp->lwp_tid);
810#ifdef INVARIANTS
f9235b6d 811 KASSERT(crit_count == td->td_critcount,
3933a3ab 812 ("trap: critical section count mismatch! %d/%d",
f9235b6d 813 crit_count, td->td_pri));
3933a3ab
MD
814 KASSERT(curstop == td->td_toks_stop,
815 ("trap: extra tokens held after trap! %ld/%ld",
816 curstop - &td->td_toks_base,
817 td->td_toks_stop - &td->td_toks_base));
c8fe38ae
MD
818#endif
819}
820
821static int
822trap_pfault(struct trapframe *frame, int usermode)
823{
824 vm_offset_t va;
825 struct vmspace *vm = NULL;
826 vm_map_t map;
827 int rv = 0;
1b9d3514 828 int fault_flags;
c8fe38ae
MD
829 vm_prot_t ftype;
830 thread_t td = curthread;
831 struct lwp *lp = td->td_lwp;
2883d2d8 832 struct proc *p;
c8fe38ae
MD
833
834 va = trunc_page(frame->tf_addr);
835 if (va >= VM_MIN_KERNEL_ADDRESS) {
836 /*
837 * Don't allow user-mode faults in kernel address space.
838 */
2883d2d8
MD
839 if (usermode) {
840 fault_flags = -1;
841 ftype = -1;
c8fe38ae 842 goto nogo;
2883d2d8 843 }
c8fe38ae
MD
844
845 map = &kernel_map;
846 } else {
847 /*
848 * This is a fault on non-kernel virtual memory.
849 * vm is initialized above to NULL. If curproc is NULL
850 * or curproc->p_vmspace is NULL the fault is fatal.
851 */
852 if (lp != NULL)
853 vm = lp->lwp_vmspace;
854
2883d2d8
MD
855 if (vm == NULL) {
856 fault_flags = -1;
857 ftype = -1;
c8fe38ae 858 goto nogo;
2883d2d8 859 }
c8fe38ae 860
4643740a
MD
861 /*
862 * Debugging, try to catch kernel faults on the user address space when not inside
863 * on onfault (e.g. copyin/copyout) routine.
864 */
865 if (usermode == 0 && (td->td_pcb == NULL || td->td_pcb->pcb_onfault == NULL)) {
866 if (freeze_on_seg_fault) {
867 kprintf("trap_pfault: user address fault from kernel mode "
868 "%016lx\n", (long)frame->tf_addr);
869 while (freeze_on_seg_fault) {
870 tsleep(&freeze_on_seg_fault, 0, "frzseg", hz * 20);
871 }
872 }
873 }
c8fe38ae
MD
874 map = &vm->vm_map;
875 }
876
877 /*
878 * PGEX_I is defined only if the execute disable bit capability is
879 * supported and enabled.
880 */
881 if (frame->tf_err & PGEX_W)
882 ftype = VM_PROT_WRITE;
883#if JG
884 else if ((frame->tf_err & PGEX_I) && pg_nx != 0)
885 ftype = VM_PROT_EXECUTE;
886#endif
887 else
888 ftype = VM_PROT_READ;
889
890 if (map != &kernel_map) {
891 /*
892 * Keep swapout from messing with us during this
893 * critical time.
894 */
895 PHOLD(lp->lwp_proc);
896
897 /*
1b9d3514
MD
898 * Issue fault
899 */
900 fault_flags = 0;
901 if (usermode)
902 fault_flags |= VM_FAULT_BURST;
903 if (ftype & VM_PROT_WRITE)
904 fault_flags |= VM_FAULT_DIRTY;
905 else
906 fault_flags |= VM_FAULT_NORMAL;
907 rv = vm_fault(map, va, ftype, fault_flags);
c8fe38ae
MD
908
909 PRELE(lp->lwp_proc);
910 } else {
911 /*
912 * Don't have to worry about process locking or stacks
913 * in the kernel.
914 */
2883d2d8 915 fault_flags = VM_FAULT_NORMAL;
c8fe38ae
MD
916 rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL);
917 }
918
919 if (rv == KERN_SUCCESS)
920 return (0);
921nogo:
922 if (!usermode) {
923 if (td->td_gd->gd_intr_nesting_level == 0 &&
924 td->td_pcb->pcb_onfault) {
925 frame->tf_rip = (register_t)td->td_pcb->pcb_onfault;
926 return (0);
927 }
928 trap_fatal(frame, frame->tf_addr);
929 return (-1);
930 }
931
932 /*
b2b3ffcd 933 * NOTE: on x86_64 we have a tf_addr field in the trapframe, no
c8fe38ae
MD
934 * kludge is needed to pass the fault address to signal handlers.
935 */
2883d2d8 936 p = td->td_proc;
2deef24c 937 if (td->td_lwp->lwp_vkernel == NULL) {
d2d8515b 938 if (bootverbose || freeze_on_seg_fault || ddb_on_seg_fault) {
c98f2169
SW
939 kprintf("seg-fault ft=%04x ff=%04x addr=%p rip=%p "
940 "pid=%d p_comm=%s\n",
941 ftype, fault_flags,
942 (void *)frame->tf_addr,
943 (void *)frame->tf_rip,
944 p->p_pid, p->p_comm);
d2d8515b 945 }
3f6724a9 946#ifdef DDB
d2d8515b
MD
947 while (freeze_on_seg_fault) {
948 tsleep(p, 0, "freeze", hz * 20);
949 }
2883d2d8
MD
950 if (ddb_on_seg_fault)
951 Debugger("ddb_on_seg_fault");
3f6724a9 952#endif
2deef24c 953 }
c8fe38ae
MD
954
955 return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV);
956}
957
958static void
959trap_fatal(struct trapframe *frame, vm_offset_t eva)
960{
961 int code, ss;
962 u_int type;
963 long rsp;
964 struct soft_segment_descriptor softseg;
965 char *msg;
966
967 code = frame->tf_err;
968 type = frame->tf_trapno;
969 sdtossd(&gdt[IDXSEL(frame->tf_cs & 0xffff)], &softseg);
970
971 if (type <= MAX_TRAP_MSG)
972 msg = trap_msg[type];
973 else
974 msg = "UNKNOWN";
975 kprintf("\n\nFatal trap %d: %s while in %s mode\n", type, msg,
976 ISPL(frame->tf_cs) == SEL_UPL ? "user" : "kernel");
977#ifdef SMP
46d4e165 978 /* three separate prints in case of a trap on an unmapped page */
46d4e165
JG
979 kprintf("cpuid = %d; ", mycpu->gd_cpuid);
980 kprintf("lapic->id = %08x\n", lapic->id);
c8fe38ae
MD
981#endif
982 if (type == T_PAGEFLT) {
983 kprintf("fault virtual address = 0x%lx\n", eva);
984 kprintf("fault code = %s %s %s, %s\n",
985 code & PGEX_U ? "user" : "supervisor",
986 code & PGEX_W ? "write" : "read",
987 code & PGEX_I ? "instruction" : "data",
988 code & PGEX_P ? "protection violation" : "page not present");
989 }
990 kprintf("instruction pointer = 0x%lx:0x%lx\n",
991 frame->tf_cs & 0xffff, frame->tf_rip);
992 if (ISPL(frame->tf_cs) == SEL_UPL) {
993 ss = frame->tf_ss & 0xffff;
994 rsp = frame->tf_rsp;
995 } else {
996 ss = GSEL(GDATA_SEL, SEL_KPL);
997 rsp = (long)&frame->tf_rsp;
998 }
999 kprintf("stack pointer = 0x%x:0x%lx\n", ss, rsp);
1000 kprintf("frame pointer = 0x%x:0x%lx\n", ss, frame->tf_rbp);
1001 kprintf("code segment = base 0x%lx, limit 0x%lx, type 0x%x\n",
1002 softseg.ssd_base, softseg.ssd_limit, softseg.ssd_type);
1003 kprintf(" = DPL %d, pres %d, long %d, def32 %d, gran %d\n",
1004 softseg.ssd_dpl, softseg.ssd_p, softseg.ssd_long, softseg.ssd_def32,
1005 softseg.ssd_gran);
1006 kprintf("processor eflags = ");
1007 if (frame->tf_rflags & PSL_T)
1008 kprintf("trace trap, ");
1009 if (frame->tf_rflags & PSL_I)
1010 kprintf("interrupt enabled, ");
1011 if (frame->tf_rflags & PSL_NT)
1012 kprintf("nested task, ");
1013 if (frame->tf_rflags & PSL_RF)
1014 kprintf("resume, ");
1015 kprintf("IOPL = %ld\n", (frame->tf_rflags & PSL_IOPL) >> 12);
1016 kprintf("current process = ");
1017 if (curproc) {
1018 kprintf("%lu\n",
1019 (u_long)curproc->p_pid);
1020 } else {
1021 kprintf("Idle\n");
1022 }
1023 kprintf("current thread = pri %d ", curthread->td_pri);
f9235b6d 1024 if (curthread->td_critcount)
c8fe38ae
MD
1025 kprintf("(CRIT)");
1026 kprintf("\n");
1027
1028#ifdef DDB
1029 if ((debugger_on_panic || db_active) && kdb_trap(type, code, frame))
1030 return;
1031#endif
1032 kprintf("trap number = %d\n", type);
1033 if (type <= MAX_TRAP_MSG)
1034 panic("%s", trap_msg[type]);
1035 else
1036 panic("unknown/reserved trap");
1037}
1038
1039/*
1040 * Double fault handler. Called when a fault occurs while writing
1041 * a frame for a trap/exception onto the stack. This usually occurs
1042 * when the stack overflows (such is the case with infinite recursion,
1043 * for example).
1044 */
093565f2
MD
1045static __inline
1046int
1047in_kstack_guard(register_t rptr)
1048{
1049 thread_t td = curthread;
1050
1051 if ((char *)rptr >= td->td_kstack &&
1052 (char *)rptr < td->td_kstack + PAGE_SIZE) {
1053 return 1;
1054 }
1055 return 0;
1056}
1057
c8fe38ae
MD
1058void
1059dblfault_handler(struct trapframe *frame)
1060{
093565f2
MD
1061 thread_t td = curthread;
1062
1063 if (in_kstack_guard(frame->tf_rsp) || in_kstack_guard(frame->tf_rbp)) {
0174149e 1064 kprintf("DOUBLE FAULT - KERNEL STACK GUARD HIT!\n");
093565f2
MD
1065 if (in_kstack_guard(frame->tf_rsp))
1066 frame->tf_rsp = (register_t)(td->td_kstack + PAGE_SIZE);
1067 if (in_kstack_guard(frame->tf_rbp))
1068 frame->tf_rbp = (register_t)(td->td_kstack + PAGE_SIZE);
1069 } else {
0174149e 1070 kprintf("DOUBLE FAULT\n");
093565f2 1071 }
c8fe38ae
MD
1072 kprintf("\nFatal double fault\n");
1073 kprintf("rip = 0x%lx\n", frame->tf_rip);
1074 kprintf("rsp = 0x%lx\n", frame->tf_rsp);
1075 kprintf("rbp = 0x%lx\n", frame->tf_rbp);
1076#ifdef SMP
46d4e165 1077 /* three separate prints in case of a trap on an unmapped page */
46d4e165
JG
1078 kprintf("cpuid = %d; ", mycpu->gd_cpuid);
1079 kprintf("lapic->id = %08x\n", lapic->id);
c8fe38ae
MD
1080#endif
1081 panic("double fault");
1082}
1083
1084/*
7bd858e5 1085 * syscall2 - MP aware system call request C handler
c8fe38ae 1086 *
7bd858e5
MD
1087 * A system call is essentially treated as a trap except that the
1088 * MP lock is not held on entry or return. We are responsible for
1089 * obtaining the MP lock if necessary and for handling ASTs
1090 * (e.g. a task switch) prior to return.
c8fe38ae 1091 *
7bd858e5 1092 * MPSAFE
c8fe38ae
MD
1093 */
1094void
1095syscall2(struct trapframe *frame)
1096{
1097 struct thread *td = curthread;
1098 struct proc *p = td->td_proc;
1099 struct lwp *lp = td->td_lwp;
1100 caddr_t params;
1101 struct sysent *callp;
1102 register_t orig_tf_rflags;
1103 int sticks;
1104 int error;
1105 int narg;
1106#ifdef INVARIANTS
f9235b6d 1107 int crit_count = td->td_critcount;
c8fe38ae
MD
1108#endif
1109#ifdef SMP
1110 int have_mplock = 0;
1111#endif
1112 register_t *argp;
1113 u_int code;
1114 int reg, regcnt;
1115 union sysunion args;
1116 register_t *argsdst;
c8fe38ae 1117
46d4e165 1118 mycpu->gd_cnt.v_syscall++;
c8fe38ae 1119
c8fe38ae
MD
1120#ifdef DIAGNOSTIC
1121 if (ISPL(frame->tf_cs) != SEL_UPL) {
1122 get_mplock();
1123 panic("syscall");
1124 /* NOT REACHED */
1125 }
1126#endif
1127
1128 KTR_LOG(kernentry_syscall, p->p_pid, lp->lwp_tid,
4afe74da 1129 frame->tf_rax);
c8fe38ae 1130
d86a23e0 1131 userenter(td, p); /* lazy raise our priority */
c8fe38ae
MD
1132
1133 reg = 0;
1134 regcnt = 6;
1135 /*
1136 * Misc
1137 */
1138 sticks = (int)td->td_sticks;
1139 orig_tf_rflags = frame->tf_rflags;
1140
1141 /*
1142 * Virtual kernel intercept - if a VM context managed by a virtual
1143 * kernel issues a system call the virtual kernel handles it, not us.
1144 * Restore the virtual kernel context and return from its system
1145 * call. The current frame is copied out to the virtual kernel.
1146 */
1147 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) {
bb47c072 1148 vkernel_trap(lp, frame);
c8fe38ae
MD
1149 error = EJUSTRETURN;
1150 goto out;
1151 }
1152
1153 /*
1154 * Get the system call parameters and account for time
1155 */
d1368d1a
MD
1156 KASSERT(lp->lwp_md.md_regs == frame,
1157 ("Frame mismatch %p %p", lp->lwp_md.md_regs, frame));
c8fe38ae
MD
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, &params);
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 /*
b2b3ffcd 1184 * On x86_64 we get up to six arguments in registers. The rest are
a6a09809 1185 * on the stack. The first six members of 'struct trapframe' happen
c8fe38ae
MD
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
c8fe38ae 1240 /*
3919ced0
MD
1241 * NOTE: All system calls run MPSAFE now. The system call itself
1242 * is responsible for getting the MP lock.
c8fe38ae 1243 */
d2d8515b
MD
1244#ifdef SYSCALL_DEBUG
1245 uint64_t tscval = rdtsc();
1246#endif
c8fe38ae 1247 error = (*callp->sy_call)(&args);
d2d8515b
MD
1248#ifdef SYSCALL_DEBUG
1249 tscval = rdtsc() - tscval;
1250 tscval = tscval * 1000000 / tsc_frequency;
1251 if (SysCallsWorstCase[code] < tscval)
1252 SysCallsWorstCase[code] = tscval;
1253#endif
c8fe38ae
MD
1254
1255out:
1256 /*
1257 * MP SAFE (we may or may not have the MP lock at this point)
1258 */
0855a2af 1259 //kprintf("SYSMSG %d ", error);
c8fe38ae
MD
1260 switch (error) {
1261 case 0:
1262 /*
1263 * Reinitialize proc pointer `p' as it may be different
1264 * if this is a child returning from fork syscall.
1265 */
1266 p = curproc;
1267 lp = curthread->td_lwp;
1268 frame->tf_rax = args.sysmsg_fds[0];
1269 frame->tf_rdx = args.sysmsg_fds[1];
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MD
1270 frame->tf_rflags &= ~PSL_C;
1271 break;
1272 case ERESTART:
1273 /*
1274 * Reconstruct pc, we know that 'syscall' is 2 bytes.
1275 * We have to do a full context restore so that %r10
1276 * (which was holding the value of %rcx) is restored for
1277 * the next iteration.
1278 */
1279 frame->tf_rip -= frame->tf_err;
1280 frame->tf_r10 = frame->tf_rcx;
c8fe38ae
MD
1281 break;
1282 case EJUSTRETURN:
1283 break;
1284 case EASYNC:
1285 panic("Unexpected EASYNC return value (for now)");
1286 default:
1287bad:
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 }
c8fe38ae
MD
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;
f2642d5a 1305 trapsignal(lp, SIGTRAP, TRAP_TRACE);
c8fe38ae
MD
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#ifdef SMP
1329 /*
1330 * Release the MP lock if we had to get it
1331 */
c8fe38ae
MD
1332 if (have_mplock)
1333 rel_mplock();
1334#endif
1335 KTR_LOG(kernentry_syscall_ret, p->p_pid, lp->lwp_tid, error);
1336#ifdef INVARIANTS
f9235b6d 1337 KASSERT(crit_count == td->td_critcount,
c8fe38ae 1338 ("syscall: critical section count mismatch! %d/%d",
f9235b6d 1339 crit_count, td->td_pri));
3933a3ab
MD
1340 KASSERT(&td->td_toks_base == td->td_toks_stop,
1341 ("syscall: extra tokens held after trap! %ld",
1342 td->td_toks_stop - &td->td_toks_base));
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MD
1343#endif
1344}
d7f50089 1345
2b0bd8aa
MD
1346/*
1347 * NOTE: mplock not held at any point
1348 */
d7f50089
YY
1349void
1350fork_return(struct lwp *lp, struct trapframe *frame)
1351{
c8fe38ae
MD
1352 frame->tf_rax = 0; /* Child returns zero */
1353 frame->tf_rflags &= ~PSL_C; /* success */
1354 frame->tf_rdx = 1;
1355
1356 generic_lwp_return(lp, frame);
1357 KTR_LOG(kernentry_fork_ret, lp->lwp_proc->p_pid, lp->lwp_tid);
d7f50089
YY
1358}
1359
1360/*
1361 * Simplified back end of syscall(), used when returning from fork()
2b0bd8aa
MD
1362 * directly into user mode.
1363 *
1364 * This code will return back into the fork trampoline code which then
1365 * runs doreti.
1366 *
1367 * NOTE: The mplock is not held at any point.
d7f50089
YY
1368 */
1369void
1370generic_lwp_return(struct lwp *lp, struct trapframe *frame)
1371{
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MD
1372 struct proc *p = lp->lwp_proc;
1373
1374 /*
1375 * Newly forked processes are given a kernel priority. We have to
1376 * adjust the priority to a normal user priority and fake entry
1377 * into the kernel (call userenter()) to install a passive release
1378 * function just in case userret() decides to stop the process. This
1379 * can occur when ^Z races a fork. If we do not install the passive
1380 * release function the current process designation will not be
1381 * released when the thread goes to sleep.
1382 */
1383 lwkt_setpri_self(TDPRI_USER_NORM);
d86a23e0 1384 userenter(lp->lwp_thread, p);
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MD
1385 userret(lp, frame, 0);
1386#ifdef KTRACE
1387 if (KTRPOINT(lp->lwp_thread, KTR_SYSRET))
1388 ktrsysret(lp, SYS_fork, 0, 0);
1389#endif
4643740a 1390 lp->lwp_flags |= LWP_PASSIVE_ACQ;
c8fe38ae 1391 userexit(lp);
4643740a 1392 lp->lwp_flags &= ~LWP_PASSIVE_ACQ;
d7f50089
YY
1393}
1394
1395/*
1396 * If PGEX_FPFAULT is set then set FP_VIRTFP in the PCB to force a T_DNA
1397 * fault (which is then passed back to the virtual kernel) if an attempt is
1398 * made to use the FP unit.
c8fe38ae 1399 *
d7f50089
YY
1400 * XXX this is a fairly big hack.
1401 */
1402void
1403set_vkernel_fp(struct trapframe *frame)
1404{
2deef24c
JG
1405 struct thread *td = curthread;
1406
1407 if (frame->tf_xflags & PGEX_FPFAULT) {
1408 td->td_pcb->pcb_flags |= FP_VIRTFP;
1409 if (mdcpu->gd_npxthread == td)
1410 npxexit();
1411 } else {
1412 td->td_pcb->pcb_flags &= ~FP_VIRTFP;
1413 }
d7f50089 1414}
bb47c072
MD
1415
1416/*
1417 * Called from vkernel_trap() to fixup the vkernel's syscall
1418 * frame for vmspace_ctl() return.
1419 */
1420void
1421cpu_vkernel_trap(struct trapframe *frame, int error)
1422{
1423 frame->tf_rax = error;
1424 if (error)
1425 frame->tf_rflags |= PSL_C;
1426 else
1427 frame->tf_rflags &= ~PSL_C;
1428}