kernel: Make SMP support default (and non-optional).
[dragonfly.git] / sys / platform / pc64 / x86_64 / trap.c
CommitLineData
d7f50089 1/*-
d7f50089
YY
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
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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 92
c8fe38ae
MD
93#define MAKEMPSAFE(have_mplock) \
94 if (have_mplock == 0) { \
95 get_mplock(); \
96 have_mplock = 1; \
97 }
98
c8fe38ae 99extern void trap(struct trapframe *frame);
c8fe38ae
MD
100
101static int trap_pfault(struct trapframe *, int);
102static void trap_fatal(struct trapframe *, vm_offset_t);
103void dblfault_handler(struct trapframe *frame);
104
c8fe38ae
MD
105#define MAX_TRAP_MSG 30
106static 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
141static int ddb_on_nmi = 1;
142SYSCTL_INT(_machdep, OID_AUTO, ddb_on_nmi, CTLFLAG_RW,
143 &ddb_on_nmi, 0, "Go to DDB on NMI");
2883d2d8
MD
144static int ddb_on_seg_fault = 0;
145SYSCTL_INT(_machdep, OID_AUTO, ddb_on_seg_fault, CTLFLAG_RW,
146 &ddb_on_seg_fault, 0, "Go to DDB on user seg-fault");
d2d8515b
MD
147static int freeze_on_seg_fault = 0;
148SYSCTL_INT(_machdep, OID_AUTO, freeze_on_seg_fault, CTLFLAG_RW,
149 &freeze_on_seg_fault, 0, "Go to DDB on user seg-fault");
c8fe38ae
MD
150#endif
151static int panic_on_nmi = 1;
152SYSCTL_INT(_machdep, OID_AUTO, panic_on_nmi, CTLFLAG_RW,
153 &panic_on_nmi, 0, "Panic on NMI");
154static int fast_release;
155SYSCTL_INT(_machdep, OID_AUTO, fast_release, CTLFLAG_RW,
156 &fast_release, 0, "Passive Release was optimal");
157static int slow_release;
158SYSCTL_INT(_machdep, OID_AUTO, slow_release, CTLFLAG_RW,
159 &slow_release, 0, "Passive Release was nonoptimal");
c8fe38ae 160
d2d8515b
MD
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
167uint64_t SysCallsWorstCase[SYS_MAXSYSCALL];
168#endif
169
c8fe38ae 170/*
7bd858e5 171 * Passively intercepts the thread switch function to increase
c8fe38ae
MD
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.
7bd858e5 174 *
d86a23e0 175 * Synchronizes td_ucred with p_ucred. This is used by system calls,
7bd858e5
MD
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.
c8fe38ae 179 */
c8fe38ae 180static __inline void
d86a23e0 181userenter(struct thread *curtd, struct proc *curp)
c8fe38ae 182{
7bd858e5
MD
183 struct ucred *ocred;
184 struct ucred *ncred;
185
3824f392 186 curtd->td_release = lwkt_passive_release;
7bd858e5 187
d86a23e0
MD
188 if (curtd->td_ucred != curp->p_ucred) {
189 ncred = crhold(curp->p_ucred);
190 ocred = curtd->td_ucred;
191 curtd->td_ucred = ncred;
7bd858e5
MD
192 if (ocred)
193 crfree(ocred);
194 }
4643740a 195
1fdd109e 196#ifdef DDB
4643740a
MD
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 }
1fdd109e 205#endif
c8fe38ae
MD
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 */
216static void
217userret(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 */
4643740a 227 if (p->p_flags & P_PROFIL) {
bab69519 228 addupc_task(p, frame->tf_rip,
c8fe38ae
MD
229 (u_int)((int)lp->lwp_thread->td_sticks - sticks));
230 }
231
232recheck:
233 /*
234 * If the jungle wants us dead, so be it.
235 */
4643740a 236 if (lp->lwp_mpflags & LWP_MP_WEXIT) {
b5c4d81f 237 lwkt_gettoken(&p->p_token);
c8fe38ae 238 lwp_exit(0);
b5c4d81f 239 lwkt_reltoken(&p->p_token); /* NOT REACHED */
c8fe38ae
MD
240 }
241
242 /*
243 * Block here if we are in a stopped state.
244 */
5ea440eb 245 if (p->p_stat == SSTOP || dump_stop_usertds) {
4643740a 246 lwkt_gettoken(&p->p_token);
c8fe38ae 247 tstop();
4643740a 248 lwkt_reltoken(&p->p_token);
c8fe38ae
MD
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 */
4643740a 256 if (p->p_flags & (P_SIGVTALRM | P_SIGPROF | P_UPCALLPEND)) {
fc509460 257 lwkt_gettoken(&p->p_token);
4643740a
MD
258 if (p->p_flags & P_SIGVTALRM) {
259 p->p_flags &= ~P_SIGVTALRM;
898e34b3
MD
260 ksignal(p, SIGVTALRM);
261 }
4643740a
MD
262 if (p->p_flags & P_SIGPROF) {
263 p->p_flags &= ~P_SIGPROF;
898e34b3
MD
264 ksignal(p, SIGPROF);
265 }
4643740a
MD
266 if (p->p_flags & P_UPCALLPEND) {
267 p->p_flags &= ~P_UPCALLPEND;
898e34b3
MD
268 postupcall(lp);
269 }
fc509460 270 lwkt_reltoken(&p->p_token);
c8fe38ae
MD
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.
2883d2d8
MD
277 *
278 * WARNING! postsig() can exit and not return.
c8fe38ae 279 */
e473f776 280 if ((sig = CURSIG_TRACE(lp)) != 0) {
fc509460 281 lwkt_gettoken(&p->p_token);
c8fe38ae 282 postsig(sig);
fc509460 283 lwkt_reltoken(&p->p_token);
c8fe38ae
MD
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 */
4643740a 292 if (p->p_flags & P_SWAPPEDOUT) {
616516c8 293 lwkt_gettoken(&p->p_token);
c8fe38ae 294 get_mplock();
4643740a 295 p->p_flags |= P_SWAPWAIT;
c8fe38ae 296 swapin_request();
4643740a 297 if (p->p_flags & P_SWAPWAIT)
c8fe38ae 298 tsleep(p, PCATCH, "SWOUT", 0);
4643740a 299 p->p_flags &= ~P_SWAPWAIT;
c8fe38ae 300 rel_mplock();
616516c8 301 lwkt_reltoken(&p->p_token);
c8fe38ae
MD
302 goto recheck;
303 }
304
305 /*
6562e2d8
MD
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.
c8fe38ae 310 */
6562e2d8
MD
311 if (lp->lwp_flags & LWP_OLDMASK) {
312 lp->lwp_flags &= ~LWP_OLDMASK;
313 lp->lwp_sigmask = lp->lwp_oldsigmask;
314 goto recheck;
315 }
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;
bab69519 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
c8fe38ae
MD
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 */
3824f392 344 lwkt_passive_recover(td);
89ffa1cf 345
e3e6be1f
MD
346 /* WARNING: we may have migrated cpu's */
347 /* gd = td->td_gd; */
348
89ffa1cf
SS
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);
c8fe38ae
MD
354}
355
0855a2af
JG
356#if !defined(KTR_KERNENTRY)
357#define KTR_KERNENTRY KTR_ALL
358#endif
359KTR_INFO_MASTER(kernentry);
5bf48697 360KTR_INFO(KTR_KERNENTRY, kernentry, trap, 0,
0cccd3b7 361 "TRAP(pid %d, tid %d, trapno %ld, eva %lu)",
5bf48697 362 pid_t pid, lwpid_t tid, register_t trapno, vm_offset_t eva);
0cccd3b7 363KTR_INFO(KTR_KERNENTRY, kernentry, trap_ret, 0, "TRAP_RET(pid %d, tid %d)",
5bf48697 364 pid_t pid, lwpid_t tid);
0cccd3b7 365KTR_INFO(KTR_KERNENTRY, kernentry, syscall, 0, "SYSC(pid %d, tid %d, nr %ld)",
5bf48697 366 pid_t pid, lwpid_t tid, register_t trapno);
0cccd3b7 367KTR_INFO(KTR_KERNENTRY, kernentry, syscall_ret, 0, "SYSRET(pid %d, tid %d, err %d)",
5bf48697 368 pid_t pid, lwpid_t tid, int err);
0cccd3b7 369KTR_INFO(KTR_KERNENTRY, kernentry, fork_ret, 0, "FORKRET(pid %d, tid %d)",
5bf48697 370 pid_t pid, lwpid_t tid);
0855a2af 371
c8fe38ae
MD
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
bab69519 387 * necessary to properly take fatal kernel traps on SMP machines if
c8fe38ae
MD
388 * get_mplock() has to block.
389 */
390
391void
392trap(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;
c8fe38ae 400 int have_mplock = 0;
c8fe38ae 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 */
c8fe38ae 472 i = SIGILL;
bab69519 473 ucode = ILL_PRVOPC;
c8fe38ae
MD
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;
bab69519 480 ucode = (type == T_TRCTRAP ? TRAP_TRACE : TRAP_BRKPT);
c8fe38ae
MD
481 break;
482
483 case T_ARITHTRAP: /* arithmetic trap */
484 ucode = code;
485 i = SIGFPE;
c8fe38ae
MD
486 break;
487
488 case T_ASTFLT: /* Allow process switch */
489 mycpu->gd_cnt.v_soft++;
490 if (mycpu->gd_reqflags & RQF_AST_OWEUPC) {
2a418930
MD
491 atomic_clear_int(&mycpu->gd_reqflags,
492 RQF_AST_OWEUPC);
c8fe38ae
MD
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 */
f2642d5a
AH
499 i = SIGBUS;
500 ucode = BUS_OBJERR;
501 break;
bab69519 502 case T_STKFLT: /* stack fault */
c8fe38ae 503 case T_SEGNPFLT: /* segment not present fault */
f2642d5a
AH
504 i = SIGBUS;
505 ucode = BUS_ADRERR;
506 break;
c8fe38ae
MD
507 case T_TSSFLT: /* invalid TSS fault */
508 case T_DOUBLEFLT: /* double fault */
509 default:
c8fe38ae 510 i = SIGBUS;
bab69519 511 ucode = BUS_OBJERR;
c8fe38ae
MD
512 break;
513
514 case T_PAGEFLT: /* page fault */
c8fe38ae 515 i = trap_pfault(frame, TRUE);
d2d8515b 516 if (frame->tf_rip == 0) {
973c11b9 517 kprintf("T_PAGEFLT: Warning %%rip == 0!\n");
1fdd109e
SW
518#ifdef DDB
519 while (freeze_on_seg_fault)
d2d8515b 520 tsleep(p, 0, "freeze", hz * 20);
1fdd109e 521#endif
d2d8515b 522 }
bab69519 523 if (i == -1 || i == 0)
c8fe38ae
MD
524 goto out;
525
bab69519 526
f2642d5a
AH
527 if (i == SIGSEGV)
528 ucode = SEGV_MAPERR;
bab69519
JM
529 else {
530 i = SIGSEGV;
531 ucode = SEGV_ACCERR;
532 }
c8fe38ae
MD
533 break;
534
535 case T_DIVIDE: /* integer divide fault */
536 ucode = FPE_INTDIV;
537 i = SIGFPE;
538 break;
539
775ce2da 540#if NISA > 0
c8fe38ae
MD
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;
775ce2da 559#endif /* NISA > 0 */
c8fe38ae
MD
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 */
f2642d5a 603 ucode = ILL_COPROC;
c8fe38ae
MD
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 */
c8fe38ae
MD
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 */
c8fe38ae 645 if (mycpu->gd_intr_nesting_level == 0) {
93ad6da2
MD
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) {
c8fe38ae
MD
653 frame->tf_rip = (register_t)
654 td->td_pcb->pcb_onfault;
655 goto out2;
656 }
89ffa1cf
SS
657 if (frame->tf_rip == (long)doreti_iret) {
658 frame->tf_rip = (long)doreti_iret_fault;
659 goto out2;
660 }
c8fe38ae
MD
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 */
f2642d5a 730 ucode = TRAP_BRKPT;
c8fe38ae
MD
731#ifdef DDB
732 MAKEMPSAFE(have_mplock);
733 if (kdb_trap(type, 0, frame))
734 goto out2;
735#endif
736 break;
737
775ce2da 738#if NISA > 0
c8fe38ae
MD
739 case T_NMI:
740 MAKEMPSAFE(have_mplock);
741 /* machine/parity/power fail/"kitchen sink" faults */
c8fe38ae
MD
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);
73e24181
MD
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);
c8fe38ae
MD
771 goto out;
772 }
773
bab69519 774 /* Translate fault for emulators (e.g. Linux) */
c8fe38ae
MD
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
791out:
c8fe38ae
MD
792 userret(lp, frame, sticks);
793 userexit(lp);
794out2: ;
c8fe38ae
MD
795 if (have_mplock)
796 rel_mplock();
c8fe38ae
MD
797 if (p != NULL && lp != NULL)
798 KTR_LOG(kernentry_trap_ret, p->p_pid, lp->lwp_tid);
799#ifdef INVARIANTS
f9235b6d 800 KASSERT(crit_count == td->td_critcount,
3933a3ab 801 ("trap: critical section count mismatch! %d/%d",
f9235b6d 802 crit_count, td->td_pri));
3933a3ab
MD
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));
c8fe38ae
MD
807#endif
808}
809
810static int
811trap_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;
1b9d3514 817 int fault_flags;
c8fe38ae
MD
818 vm_prot_t ftype;
819 thread_t td = curthread;
820 struct lwp *lp = td->td_lwp;
2883d2d8 821 struct proc *p;
c8fe38ae
MD
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 */
2883d2d8
MD
828 if (usermode) {
829 fault_flags = -1;
830 ftype = -1;
c8fe38ae 831 goto nogo;
2883d2d8 832 }
c8fe38ae
MD
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
2883d2d8
MD
844 if (vm == NULL) {
845 fault_flags = -1;
846 ftype = -1;
c8fe38ae 847 goto nogo;
2883d2d8 848 }
c8fe38ae 849
4643740a
MD
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 */
93ad6da2
MD
854 if (usermode == 0 && (td->td_pcb == NULL ||
855 td->td_pcb->pcb_onfault == NULL)) {
1fdd109e 856#ifdef DDB
4643740a
MD
857 if (freeze_on_seg_fault) {
858 kprintf("trap_pfault: user address fault from kernel mode "
859 "%016lx\n", (long)frame->tf_addr);
1fdd109e 860 while (freeze_on_seg_fault)
4643740a 861 tsleep(&freeze_on_seg_fault, 0, "frzseg", hz * 20);
4643740a 862 }
1fdd109e 863#endif
4643740a 864 }
c8fe38ae
MD
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
1b9d3514
MD
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);
c8fe38ae
MD
899
900 PRELE(lp->lwp_proc);
901 } else {
902 /*
bab69519
JM
903 * Don't have to worry about process locking or stacks in the
904 * kernel.
c8fe38ae 905 */
2883d2d8 906 fault_flags = VM_FAULT_NORMAL;
c8fe38ae
MD
907 rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL);
908 }
c8fe38ae
MD
909 if (rv == KERN_SUCCESS)
910 return (0);
911nogo:
912 if (!usermode) {
93ad6da2
MD
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) {
c8fe38ae
MD
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 /*
b2b3ffcd 928 * NOTE: on x86_64 we have a tf_addr field in the trapframe, no
c8fe38ae
MD
929 * kludge is needed to pass the fault address to signal handlers.
930 */
2883d2d8 931 p = td->td_proc;
2deef24c 932 if (td->td_lwp->lwp_vkernel == NULL) {
1fdd109e 933#ifdef DDB
d2d8515b 934 if (bootverbose || freeze_on_seg_fault || ddb_on_seg_fault) {
1fdd109e
SW
935#else
936 if (bootverbose) {
937#endif
c98f2169 938 kprintf("seg-fault ft=%04x ff=%04x addr=%p rip=%p "
3338cc67 939 "pid=%d cpu=%d p_comm=%s\n",
c98f2169
SW
940 ftype, fault_flags,
941 (void *)frame->tf_addr,
942 (void *)frame->tf_rip,
3338cc67 943 p->p_pid, mycpu->gd_cpuid, p->p_comm);
d2d8515b 944 }
3f6724a9 945#ifdef DDB
d2d8515b
MD
946 while (freeze_on_seg_fault) {
947 tsleep(p, 0, "freeze", hz * 20);
948 }
2883d2d8
MD
949 if (ddb_on_seg_fault)
950 Debugger("ddb_on_seg_fault");
3f6724a9 951#endif
2deef24c 952 }
c8fe38ae
MD
953
954 return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV);
955}
956
957static void
958trap_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");
46d4e165 976 /* three separate prints in case of a trap on an unmapped page */
46d4e165
JG
977 kprintf("cpuid = %d; ", mycpu->gd_cpuid);
978 kprintf("lapic->id = %08x\n", lapic->id);
c8fe38ae
MD
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 {
93ad6da2
MD
993 /*
994 * NOTE: in 64-bit mode traps push rsp/ss even if no ring
995 * change occurs.
996 */
c8fe38ae 997 ss = GSEL(GDATA_SEL, SEL_KPL);
93ad6da2 998 rsp = frame->tf_rsp;
c8fe38ae
MD
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);
f9235b6d 1025 if (curthread->td_critcount)
c8fe38ae
MD
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 */
093565f2
MD
1046static __inline
1047int
1048in_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
c8fe38ae
MD
1059void
1060dblfault_handler(struct trapframe *frame)
1061{
093565f2
MD
1062 thread_t td = curthread;
1063
1064 if (in_kstack_guard(frame->tf_rsp) || in_kstack_guard(frame->tf_rbp)) {
0174149e 1065 kprintf("DOUBLE FAULT - KERNEL STACK GUARD HIT!\n");
093565f2
MD
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 {
0174149e 1071 kprintf("DOUBLE FAULT\n");
093565f2 1072 }
c8fe38ae
MD
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);
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 panic("double fault");
1081}
1082
1083/*
7bd858e5 1084 * syscall2 - MP aware system call request C handler
c8fe38ae 1085 *
7bd858e5
MD
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.
c8fe38ae 1090 *
7bd858e5 1091 * MPSAFE
c8fe38ae
MD
1092 */
1093void
1094syscall2(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
f9235b6d 1106 int crit_count = td->td_critcount;
c8fe38ae 1107#endif
c8fe38ae 1108 int have_mplock = 0;
c8fe38ae
MD
1109 register_t *argp;
1110 u_int code;
1111 int reg, regcnt;
1112 union sysunion args;
1113 register_t *argsdst;
c8fe38ae 1114
46d4e165 1115 mycpu->gd_cnt.v_syscall++;
c8fe38ae 1116
c8fe38ae
MD
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,
4afe74da 1126 frame->tf_rax);
c8fe38ae 1127
d86a23e0 1128 userenter(td, p); /* lazy raise our priority */
c8fe38ae
MD
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) {
bb47c072 1145 vkernel_trap(lp, frame);
c8fe38ae
MD
1146 error = EJUSTRETURN;
1147 goto out;
1148 }
1149
1150 /*
1151 * Get the system call parameters and account for time
1152 */
d1368d1a
MD
1153 KASSERT(lp->lwp_md.md_regs == frame,
1154 ("Frame mismatch %p %p", lp->lwp_md.md_regs, frame));
c8fe38ae
MD
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, &params);
1162 } else {
1163 if (code == SYS_syscall || code == SYS___syscall) {
1164 code = frame->tf_rdi;
1165 reg++;
1166 regcnt--;
1167 }
1168 }
1169
bab69519
JM
1170 if (p->p_sysent->sv_mask)
1171 code &= p->p_sysent->sv_mask;
c8fe38ae
MD
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 /*
b2b3ffcd 1181 * On x86_64 we get up to six arguments in registers. The rest are
a6a09809 1182 * on the stack. The first six members of 'struct trapframe' happen
c8fe38ae
MD
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],
bab69519 1200 (narg - regcnt) * sizeof(register_t));
c8fe38ae
MD
1201 if (error) {
1202#ifdef KTRACE
1203 if (KTRPOINT(td, KTR_SYSCALL)) {
1204 MAKEMPSAFE(have_mplock);
bab69519 1205
c8fe38ae
MD
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
c8fe38ae 1237 /*
3919ced0
MD
1238 * NOTE: All system calls run MPSAFE now. The system call itself
1239 * is responsible for getting the MP lock.
c8fe38ae 1240 */
d2d8515b
MD
1241#ifdef SYSCALL_DEBUG
1242 uint64_t tscval = rdtsc();
1243#endif
c8fe38ae 1244 error = (*callp->sy_call)(&args);
d2d8515b
MD
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
c8fe38ae
MD
1251
1252out:
1253 /*
1254 * MP SAFE (we may or may not have the MP lock at this point)
1255 */
0855a2af 1256 //kprintf("SYSMSG %d ", error);
c8fe38ae
MD
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];
c8fe38ae
MD
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 */
3338cc67
MD
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);
c8fe38ae
MD
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);
c8fe38ae
MD
1328 /*
1329 * Release the MP lock if we had to get it
1330 */
c8fe38ae
MD
1331 if (have_mplock)
1332 rel_mplock();
c8fe38ae
MD
1333 KTR_LOG(kernentry_syscall_ret, p->p_pid, lp->lwp_tid, error);
1334#ifdef INVARIANTS
f9235b6d 1335 KASSERT(crit_count == td->td_critcount,
c8fe38ae 1336 ("syscall: critical section count mismatch! %d/%d",
f9235b6d 1337 crit_count, td->td_pri));
3933a3ab
MD
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));
c8fe38ae
MD
1341#endif
1342}
d7f50089 1343
2b0bd8aa
MD
1344/*
1345 * NOTE: mplock not held at any point
1346 */
d7f50089
YY
1347void
1348fork_return(struct lwp *lp, struct trapframe *frame)
1349{
c8fe38ae
MD
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);
d7f50089
YY
1356}
1357
1358/*
1359 * Simplified back end of syscall(), used when returning from fork()
2b0bd8aa
MD
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.
d7f50089
YY
1366 */
1367void
1368generic_lwp_return(struct lwp *lp, struct trapframe *frame)
1369{
c8fe38ae
MD
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);
d86a23e0 1382 userenter(lp->lwp_thread, p);
c8fe38ae
MD
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
4643740a 1388 lp->lwp_flags |= LWP_PASSIVE_ACQ;
c8fe38ae 1389 userexit(lp);
4643740a 1390 lp->lwp_flags &= ~LWP_PASSIVE_ACQ;
d7f50089
YY
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.
c8fe38ae 1397 *
d7f50089
YY
1398 * XXX this is a fairly big hack.
1399 */
1400void
1401set_vkernel_fp(struct trapframe *frame)
1402{
2deef24c
JG
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 }
d7f50089 1412}
bb47c072
MD
1413
1414/*
1415 * Called from vkernel_trap() to fixup the vkernel's syscall
1416 * frame for vmspace_ctl() return.
1417 */
1418void
1419cpu_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}