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.
8 * This code is derived from software contributed to Berkeley by
9 * the University of Utah, and William Jolitz.
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
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.
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
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 $
44 * x86_64 Trap and System call handling
50 #include "opt_ktrace.h"
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>
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>
65 #include <sys/ktrace.h>
68 #include <sys/sysmsg.h>
69 #include <sys/sysproto.h>
70 #include <sys/sysunion.h>
74 #include <vm/vm_extern.h>
75 #include <vm/vm_kern.h>
76 #include <vm/vm_param.h>
77 #include <machine/cpu.h>
78 #include <machine/pcb.h>
79 #include <machine/smp.h>
80 #include <machine/thread.h>
81 #include <machine/clock.h>
82 #include <machine/vmparam.h>
83 #include <machine/md_var.h>
84 #include <machine_base/isa/isa_intr.h>
85 #include <machine_base/apic/lapic.h>
89 #include <sys/thread2.h>
90 #include <sys/mplock2.h>
91 #include <sys/spinlock2.h>
93 #define MAKEMPSAFE(have_mplock) \
94 if (have_mplock == 0) { \
99 extern void trap(struct trapframe
*frame
);
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
);
105 #define MAX_TRAP_MSG 30
106 static char *trap_msg
[] = {
108 "privileged instruction fault", /* 1 T_PRIVINFLT */
110 "breakpoint instruction fault", /* 3 T_BPTFLT */
113 "arithmetic trap", /* 6 T_ARITHTRAP */
114 "system forced exception", /* 7 T_ASTFLT */
116 "general protection fault", /* 9 T_PROTFLT */
117 "trace trap", /* 10 T_TRCTRAP */
119 "page fault", /* 12 T_PAGEFLT */
121 "alignment fault", /* 14 T_ALIGNFLT */
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 */
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");
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");
162 * System call debugging records the worst-case system call
163 * overhead (inclusive of blocking), but may be inaccurate.
165 /*#define SYSCALL_DEBUG*/
167 uint64_t SysCallsWorstCase
[SYS_MAXSYSCALL
];
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.
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.
180 * To avoid races with another thread updating p_ucred we obtain p_spin.
181 * The other thread doing the update will obtain both p_token and p_spin.
182 * In the case where the cached cred pointer matches, we will already have
183 * the ref and we don't have to do one blessed thing.
186 userenter(struct thread
*curtd
, struct proc
*curp
)
191 curtd
->td_release
= lwkt_passive_release
;
193 if (curtd
->td_ucred
!= curp
->p_ucred
) {
194 spin_lock(&curp
->p_spin
);
195 ncred
= crhold(curp
->p_ucred
);
196 spin_unlock(&curp
->p_spin
);
197 ocred
= curtd
->td_ucred
;
198 curtd
->td_ucred
= ncred
;
205 * Debugging, remove top two user stack pages to catch kernel faults
207 if (freeze_on_seg_fault
> 1 && curtd
->td_lwp
) {
208 pmap_remove(vmspace_pmap(curtd
->td_lwp
->lwp_vmspace
),
209 0x00007FFFFFFFD000LU
,
210 0x0000800000000000LU
);
216 * Handle signals, upcalls, profiling, and other AST's and/or tasks that
217 * must be completed before we can return to or try to return to userland.
219 * Note that td_sticks is a 64 bit quantity, but there's no point doing 64
220 * arithmatic on the delta calculation so the absolute tick values are
221 * truncated to an integer.
224 userret(struct lwp
*lp
, struct trapframe
*frame
, int sticks
)
226 struct proc
*p
= lp
->lwp_proc
;
230 * Charge system time if profiling. Note: times are in microseconds.
231 * This may do a copyout and block, so do it first even though it
232 * means some system time will be charged as user time.
234 if (p
->p_flags
& P_PROFIL
) {
235 addupc_task(p
, frame
->tf_rip
,
236 (u_int
)((int)lp
->lwp_thread
->td_sticks
- sticks
));
241 * Specific on-return-to-usermode checks (LWP_MP_WEXIT,
242 * LWP_MP_VNLRU, etc).
244 if (lp
->lwp_mpflags
& LWP_MP_URETMASK
)
248 * Block here if we are in a stopped state.
250 if (STOPLWP(p
, lp
)) {
251 lwkt_gettoken(&p
->p_token
);
253 lwkt_reltoken(&p
->p_token
);
256 while (dump_stop_usertds
) {
257 tsleep(&dump_stop_usertds
, 0, "dumpstp", 0);
261 * Post any pending upcalls. If running a virtual kernel be sure
262 * to restore the virtual kernel's vmspace before posting the upcall.
264 if (p
->p_flags
& (P_SIGVTALRM
| P_SIGPROF
)) {
265 lwkt_gettoken(&p
->p_token
);
266 if (p
->p_flags
& P_SIGVTALRM
) {
267 p
->p_flags
&= ~P_SIGVTALRM
;
268 ksignal(p
, SIGVTALRM
);
270 if (p
->p_flags
& P_SIGPROF
) {
271 p
->p_flags
&= ~P_SIGPROF
;
274 lwkt_reltoken(&p
->p_token
);
279 * Post any pending signals. If running a virtual kernel be sure
280 * to restore the virtual kernel's vmspace before posting the signal.
282 * WARNING! postsig() can exit and not return.
284 if ((sig
= CURSIG_TRACE(lp
)) != 0) {
285 lwkt_gettoken(&p
->p_token
);
287 lwkt_reltoken(&p
->p_token
);
292 * block here if we are swapped out, but still process signals
293 * (such as SIGKILL). proc0 (the swapin scheduler) is already
294 * aware of our situation, we do not have to wake it up.
296 if (p
->p_flags
& P_SWAPPEDOUT
) {
297 lwkt_gettoken(&p
->p_token
);
299 p
->p_flags
|= P_SWAPWAIT
;
301 if (p
->p_flags
& P_SWAPWAIT
)
302 tsleep(p
, PCATCH
, "SWOUT", 0);
303 p
->p_flags
&= ~P_SWAPWAIT
;
305 lwkt_reltoken(&p
->p_token
);
310 * In a multi-threaded program it is possible for a thread to change
311 * signal state during a system call which temporarily changes the
312 * signal mask. In this case postsig() might not be run and we
313 * have to restore the mask ourselves.
315 if (lp
->lwp_flags
& LWP_OLDMASK
) {
316 lp
->lwp_flags
&= ~LWP_OLDMASK
;
317 lp
->lwp_sigmask
= lp
->lwp_oldsigmask
;
323 * Cleanup from userenter and any passive release that might have occured.
324 * We must reclaim the current-process designation before we can return
325 * to usermode. We also handle both LWKT and USER reschedule requests.
328 userexit(struct lwp
*lp
)
330 struct thread
*td
= lp
->lwp_thread
;
331 /* globaldata_t gd = td->td_gd; */
334 * Handle stop requests at kernel priority. Any requests queued
335 * after this loop will generate another AST.
337 while (STOPLWP(lp
->lwp_proc
, lp
)) {
338 lwkt_gettoken(&lp
->lwp_proc
->p_token
);
340 lwkt_reltoken(&lp
->lwp_proc
->p_token
);
344 * Reduce our priority in preparation for a return to userland. If
345 * our passive release function was still in place, our priority was
346 * never raised and does not need to be reduced.
348 lwkt_passive_recover(td
);
350 /* WARNING: we may have migrated cpu's */
351 /* gd = td->td_gd; */
354 * Become the current user scheduled process if we aren't already,
355 * and deal with reschedule requests and other factors.
357 lp
->lwp_proc
->p_usched
->acquire_curproc(lp
);
360 #if !defined(KTR_KERNENTRY)
361 #define KTR_KERNENTRY KTR_ALL
363 KTR_INFO_MASTER(kernentry
);
364 KTR_INFO(KTR_KERNENTRY
, kernentry
, trap
, 0,
365 "TRAP(pid %d, tid %d, trapno %ld, eva %lu)",
366 pid_t pid
, lwpid_t tid
, register_t trapno
, vm_offset_t eva
);
367 KTR_INFO(KTR_KERNENTRY
, kernentry
, trap_ret
, 0, "TRAP_RET(pid %d, tid %d)",
368 pid_t pid
, lwpid_t tid
);
369 KTR_INFO(KTR_KERNENTRY
, kernentry
, syscall
, 0, "SYSC(pid %d, tid %d, nr %ld)",
370 pid_t pid
, lwpid_t tid
, register_t trapno
);
371 KTR_INFO(KTR_KERNENTRY
, kernentry
, syscall_ret
, 0, "SYSRET(pid %d, tid %d, err %d)",
372 pid_t pid
, lwpid_t tid
, int err
);
373 KTR_INFO(KTR_KERNENTRY
, kernentry
, fork_ret
, 0, "FORKRET(pid %d, tid %d)",
374 pid_t pid
, lwpid_t tid
);
377 * Exception, fault, and trap interface to the kernel.
378 * This common code is called from assembly language IDT gate entry
379 * routines that prepare a suitable stack frame, and restore this
380 * frame after the exception has been processed.
382 * This function is also called from doreti in an interlock to handle ASTs.
383 * For example: hardwareint->INTROUTINE->(set ast)->doreti->trap
385 * NOTE! We have to retrieve the fault address prior to obtaining the
386 * MP lock because get_mplock() may switch out. YYY cr2 really ought
387 * to be retrieved by the assembly code, not here.
389 * XXX gd_trap_nesting_level currently prevents lwkt_switch() from panicing
390 * if an attempt is made to switch from a fast interrupt or IPI. This is
391 * necessary to properly take fatal kernel traps on SMP machines if
392 * get_mplock() has to block.
396 trap(struct trapframe
*frame
)
398 struct globaldata
*gd
= mycpu
;
399 struct thread
*td
= gd
->gd_curthread
;
400 struct lwp
*lp
= td
->td_lwp
;
403 int i
= 0, ucode
= 0, type
, code
;
406 int crit_count
= td
->td_critcount
;
407 lwkt_tokref_t curstop
= td
->td_toks_stop
;
416 * We need to allow T_DNA faults when the debugger is active since
417 * some dumping paths do large bcopy() which use the floating
418 * point registers for faster copying.
420 if (db_active
&& frame
->tf_trapno
!= T_DNA
) {
421 eva
= (frame
->tf_trapno
== T_PAGEFLT
? frame
->tf_addr
: 0);
422 ++gd
->gd_trap_nesting_level
;
423 MAKEMPSAFE(have_mplock
);
424 trap_fatal(frame
, eva
);
425 --gd
->gd_trap_nesting_level
;
432 if ((frame
->tf_rflags
& PSL_I
) == 0) {
434 * Buggy application or kernel code has disabled interrupts
435 * and then trapped. Enabling interrupts now is wrong, but
436 * it is better than running with interrupts disabled until
437 * they are accidentally enabled later.
439 type
= frame
->tf_trapno
;
440 if (ISPL(frame
->tf_cs
) == SEL_UPL
) {
441 MAKEMPSAFE(have_mplock
);
442 /* JG curproc can be NULL */
444 "pid %ld (%s): trap %d with interrupts disabled\n",
445 (long)curproc
->p_pid
, curproc
->p_comm
, type
);
446 } else if (type
!= T_NMI
&& type
!= T_BPTFLT
&&
449 * XXX not quite right, since this may be for a
450 * multiple fault in user mode.
452 MAKEMPSAFE(have_mplock
);
453 kprintf("kernel trap %d (%s @ 0x%016jx) with "
454 "interrupts disabled\n",
462 type
= frame
->tf_trapno
;
463 code
= frame
->tf_err
;
465 if (ISPL(frame
->tf_cs
) == SEL_UPL
) {
468 KTR_LOG(kernentry_trap
, p
->p_pid
, lp
->lwp_tid
,
469 frame
->tf_trapno
, eva
);
473 sticks
= (int)td
->td_sticks
;
474 KASSERT(lp
->lwp_md
.md_regs
== frame
,
475 ("Frame mismatch %p %p", lp
->lwp_md
.md_regs
, frame
));
478 case T_PRIVINFLT
: /* privileged instruction fault */
483 case T_BPTFLT
: /* bpt instruction fault */
484 case T_TRCTRAP
: /* trace trap */
485 frame
->tf_rflags
&= ~PSL_T
;
487 ucode
= (type
== T_TRCTRAP
? TRAP_TRACE
: TRAP_BRKPT
);
490 case T_ARITHTRAP
: /* arithmetic trap */
495 case T_ASTFLT
: /* Allow process switch */
496 mycpu
->gd_cnt
.v_soft
++;
497 if (mycpu
->gd_reqflags
& RQF_AST_OWEUPC
) {
498 atomic_clear_int(&mycpu
->gd_reqflags
,
500 addupc_task(p
, p
->p_prof
.pr_addr
,
505 case T_PROTFLT
: /* general protection fault */
509 case T_STKFLT
: /* stack fault */
510 case T_SEGNPFLT
: /* segment not present fault */
514 case T_TSSFLT
: /* invalid TSS fault */
515 case T_DOUBLEFLT
: /* double fault */
521 case T_PAGEFLT
: /* page fault */
522 i
= trap_pfault(frame
, TRUE
);
523 if (frame
->tf_rip
== 0) {
525 /* used for kernel debugging only */
526 while (freeze_on_seg_fault
)
527 tsleep(p
, 0, "freeze", hz
* 20);
530 if (i
== -1 || i
== 0)
542 case T_DIVIDE
: /* integer divide fault */
549 MAKEMPSAFE(have_mplock
);
550 /* machine/parity/power fail/"kitchen sink" faults */
551 if (isa_nmi(code
) == 0) {
554 * NMI can be hooked up to a pushbutton
558 kprintf ("NMI ... going to debugger\n");
559 kdb_trap(type
, 0, frame
);
563 } else if (panic_on_nmi
)
564 panic("NMI indicates hardware failure");
566 #endif /* NISA > 0 */
568 case T_OFLOW
: /* integer overflow fault */
573 case T_BOUND
: /* bounds check fault */
580 * Virtual kernel intercept - pass the DNA exception
581 * to the virtual kernel if it asked to handle it.
582 * This occurs when the virtual kernel is holding
583 * onto the FP context for a different emulated
584 * process then the one currently running.
586 * We must still call npxdna() since we may have
587 * saved FP state that the virtual kernel needs
588 * to hand over to a different emulated process.
590 if (lp
->lwp_vkernel
&& lp
->lwp_vkernel
->ve
&&
591 (td
->td_pcb
->pcb_flags
& FP_VIRTFP
)
598 * The kernel may have switched out the FP unit's
599 * state, causing the user process to take a fault
600 * when it tries to use the FP unit. Restore the
606 ucode
= FPE_FPU_NP_TRAP
;
609 case T_FPOPFLT
: /* FPU operand fetch fault */
614 case T_XMMFLT
: /* SIMD floating-point exception */
623 case T_PAGEFLT
: /* page fault */
624 trap_pfault(frame
, FALSE
);
629 * The kernel is apparently using fpu for copying.
630 * XXX this should be fatal unless the kernel has
631 * registered such use.
637 case T_STKFLT
: /* stack fault */
638 case T_PROTFLT
: /* general protection fault */
639 case T_SEGNPFLT
: /* segment not present fault */
641 * Invalid segment selectors and out of bounds
642 * %rip's and %rsp's can be set up in user mode.
643 * This causes a fault in kernel mode when the
644 * kernel tries to return to user mode. We want
645 * to get this fault so that we can fix the
646 * problem here and not have to check all the
647 * selectors and pointers when the user changes
650 if (mycpu
->gd_intr_nesting_level
== 0) {
652 * NOTE: in 64-bit mode traps push rsp/ss
653 * even if no ring change occurs.
655 if (td
->td_pcb
->pcb_onfault
&&
656 td
->td_pcb
->pcb_onfault_sp
==
658 frame
->tf_rip
= (register_t
)
659 td
->td_pcb
->pcb_onfault
;
662 if (frame
->tf_rip
== (long)doreti_iret
) {
663 frame
->tf_rip
= (long)doreti_iret_fault
;
671 * PSL_NT can be set in user mode and isn't cleared
672 * automatically when the kernel is entered. This
673 * causes a TSS fault when the kernel attempts to
674 * `iret' because the TSS link is uninitialized. We
675 * want to get this fault so that we can fix the
676 * problem here and not every time the kernel is
679 if (frame
->tf_rflags
& PSL_NT
) {
680 frame
->tf_rflags
&= ~PSL_NT
;
685 case T_TRCTRAP
: /* trace trap */
687 if (frame
->tf_rip
== (int)IDTVEC(syscall
)) {
689 * We've just entered system mode via the
690 * syscall lcall. Continue single stepping
691 * silently until the syscall handler has
696 if (frame
->tf_rip
== (int)IDTVEC(syscall
) + 1) {
698 * The syscall handler has now saved the
699 * flags. Stop single stepping it.
701 frame
->tf_rflags
&= ~PSL_T
;
707 * Ignore debug register trace traps due to
708 * accesses in the user's address space, which
709 * can happen under several conditions such as
710 * if a user sets a watchpoint on a buffer and
711 * then passes that buffer to a system call.
712 * We still want to get TRCTRAPS for addresses
713 * in kernel space because that is useful when
714 * debugging the kernel.
717 if (user_dbreg_trap()) {
719 * Reset breakpoint bits because the
722 /* XXX check upper bits here */
723 load_dr6(rdr6() & 0xfffffff0);
728 * FALLTHROUGH (TRCTRAP kernel mode, kernel address)
732 * If DDB is enabled, let it handle the debugger trap.
733 * Otherwise, debugger traps "can't happen".
737 MAKEMPSAFE(have_mplock
);
738 if (kdb_trap(type
, 0, frame
))
745 MAKEMPSAFE(have_mplock
);
746 /* machine/parity/power fail/"kitchen sink" faults */
747 if (isa_nmi(code
) == 0) {
750 * NMI can be hooked up to a pushbutton
754 kprintf ("NMI ... going to debugger\n");
755 kdb_trap(type
, 0, frame
);
759 } else if (panic_on_nmi
== 0)
762 #endif /* NISA > 0 */
764 MAKEMPSAFE(have_mplock
);
765 trap_fatal(frame
, 0);
770 * Virtual kernel intercept - if the fault is directly related to a
771 * VM context managed by a virtual kernel then let the virtual kernel
774 if (lp
->lwp_vkernel
&& lp
->lwp_vkernel
->ve
) {
775 vkernel_trap(lp
, frame
);
779 /* Translate fault for emulators (e.g. Linux) */
780 if (*p
->p_sysent
->sv_transtrap
)
781 i
= (*p
->p_sysent
->sv_transtrap
)(i
, type
);
783 MAKEMPSAFE(have_mplock
);
784 trapsignal(lp
, i
, ucode
);
787 if (type
<= MAX_TRAP_MSG
) {
788 uprintf("fatal process exception: %s",
790 if ((type
== T_PAGEFLT
) || (type
== T_PROTFLT
))
791 uprintf(", fault VA = 0x%lx", frame
->tf_addr
);
797 userret(lp
, frame
, sticks
);
802 if (p
!= NULL
&& lp
!= NULL
)
803 KTR_LOG(kernentry_trap_ret
, p
->p_pid
, lp
->lwp_tid
);
805 KASSERT(crit_count
== td
->td_critcount
,
806 ("trap: critical section count mismatch! %d/%d",
807 crit_count
, td
->td_pri
));
808 KASSERT(curstop
== td
->td_toks_stop
,
809 ("trap: extra tokens held after trap! %ld/%ld",
810 curstop
- &td
->td_toks_base
,
811 td
->td_toks_stop
- &td
->td_toks_base
));
816 trap_handle_userenter(struct thread
*td
)
818 userenter(td
, td
->td_proc
);
822 trap_handle_userexit(struct trapframe
*frame
, int sticks
)
824 struct lwp
*lp
= curthread
->td_lwp
;
827 userret(lp
, frame
, sticks
);
833 trap_pfault(struct trapframe
*frame
, int usermode
)
836 struct vmspace
*vm
= NULL
;
841 thread_t td
= curthread
;
842 struct lwp
*lp
= td
->td_lwp
;
845 va
= trunc_page(frame
->tf_addr
);
846 if (va
>= VM_MIN_KERNEL_ADDRESS
) {
848 * Don't allow user-mode faults in kernel address space.
859 * This is a fault on non-kernel virtual memory.
860 * vm is initialized above to NULL. If curproc is NULL
861 * or curproc->p_vmspace is NULL the fault is fatal.
864 vm
= lp
->lwp_vmspace
;
873 * Debugging, try to catch kernel faults on the user address
874 * space when not inside on onfault (e.g. copyin/copyout)
877 if (usermode
== 0 && (td
->td_pcb
== NULL
||
878 td
->td_pcb
->pcb_onfault
== NULL
)) {
880 if (freeze_on_seg_fault
) {
881 kprintf("trap_pfault: user address fault from kernel mode "
882 "%016lx\n", (long)frame
->tf_addr
);
883 while (freeze_on_seg_fault
)
884 tsleep(&freeze_on_seg_fault
, 0, "frzseg", hz
* 20);
892 * PGEX_I is defined only if the execute disable bit capability is
893 * supported and enabled.
895 if (frame
->tf_err
& PGEX_W
)
896 ftype
= VM_PROT_WRITE
;
898 else if ((frame
->tf_err
& PGEX_I
) && pg_nx
!= 0)
899 ftype
= VM_PROT_EXECUTE
;
902 ftype
= VM_PROT_READ
;
904 if (map
!= &kernel_map
) {
906 * Keep swapout from messing with us during this
916 fault_flags
|= VM_FAULT_BURST
;
917 if (ftype
& VM_PROT_WRITE
)
918 fault_flags
|= VM_FAULT_DIRTY
;
920 fault_flags
|= VM_FAULT_NORMAL
;
921 rv
= vm_fault(map
, va
, ftype
, fault_flags
);
926 * Don't have to worry about process locking or stacks in the
929 fault_flags
= VM_FAULT_NORMAL
;
930 rv
= vm_fault(map
, va
, ftype
, VM_FAULT_NORMAL
);
932 if (rv
== KERN_SUCCESS
)
937 * NOTE: in 64-bit mode traps push rsp/ss
938 * even if no ring change occurs.
940 if (td
->td_pcb
->pcb_onfault
&&
941 td
->td_pcb
->pcb_onfault_sp
== frame
->tf_rsp
&&
942 td
->td_gd
->gd_intr_nesting_level
== 0) {
943 frame
->tf_rip
= (register_t
)td
->td_pcb
->pcb_onfault
;
946 trap_fatal(frame
, frame
->tf_addr
);
951 * NOTE: on x86_64 we have a tf_addr field in the trapframe, no
952 * kludge is needed to pass the fault address to signal handlers.
956 if (td
->td_lwp
->lwp_vkernel
== NULL
) {
957 while (freeze_on_seg_fault
) {
958 tsleep(p
, 0, "freeze", hz
* 20);
960 if (ddb_on_seg_fault
)
961 Debugger("ddb_on_seg_fault");
965 return((rv
== KERN_PROTECTION_FAILURE
) ? SIGBUS
: SIGSEGV
);
969 trap_fatal(struct trapframe
*frame
, vm_offset_t eva
)
974 struct soft_segment_descriptor softseg
;
977 code
= frame
->tf_err
;
978 type
= frame
->tf_trapno
;
979 sdtossd(&gdt
[IDXSEL(frame
->tf_cs
& 0xffff)], &softseg
);
981 if (type
<= MAX_TRAP_MSG
)
982 msg
= trap_msg
[type
];
985 kprintf("\n\nFatal trap %d: %s while in %s mode\n", type
, msg
,
986 ISPL(frame
->tf_cs
) == SEL_UPL
? "user" : "kernel");
987 /* three separate prints in case of a trap on an unmapped page */
988 kprintf("cpuid = %d; ", mycpu
->gd_cpuid
);
989 kprintf("lapic->id = %08x\n", lapic
->id
);
990 if (type
== T_PAGEFLT
) {
991 kprintf("fault virtual address = 0x%lx\n", eva
);
992 kprintf("fault code = %s %s %s, %s\n",
993 code
& PGEX_U
? "user" : "supervisor",
994 code
& PGEX_W
? "write" : "read",
995 code
& PGEX_I
? "instruction" : "data",
996 code
& PGEX_P
? "protection violation" : "page not present");
998 kprintf("instruction pointer = 0x%lx:0x%lx\n",
999 frame
->tf_cs
& 0xffff, frame
->tf_rip
);
1000 if (ISPL(frame
->tf_cs
) == SEL_UPL
) {
1001 ss
= frame
->tf_ss
& 0xffff;
1002 rsp
= frame
->tf_rsp
;
1005 * NOTE: in 64-bit mode traps push rsp/ss even if no ring
1008 ss
= GSEL(GDATA_SEL
, SEL_KPL
);
1009 rsp
= frame
->tf_rsp
;
1011 kprintf("stack pointer = 0x%x:0x%lx\n", ss
, rsp
);
1012 kprintf("frame pointer = 0x%x:0x%lx\n", ss
, frame
->tf_rbp
);
1013 kprintf("code segment = base 0x%lx, limit 0x%lx, type 0x%x\n",
1014 softseg
.ssd_base
, softseg
.ssd_limit
, softseg
.ssd_type
);
1015 kprintf(" = DPL %d, pres %d, long %d, def32 %d, gran %d\n",
1016 softseg
.ssd_dpl
, softseg
.ssd_p
, softseg
.ssd_long
, softseg
.ssd_def32
,
1018 kprintf("processor eflags = ");
1019 if (frame
->tf_rflags
& PSL_T
)
1020 kprintf("trace trap, ");
1021 if (frame
->tf_rflags
& PSL_I
)
1022 kprintf("interrupt enabled, ");
1023 if (frame
->tf_rflags
& PSL_NT
)
1024 kprintf("nested task, ");
1025 if (frame
->tf_rflags
& PSL_RF
)
1026 kprintf("resume, ");
1027 kprintf("IOPL = %ld\n", (frame
->tf_rflags
& PSL_IOPL
) >> 12);
1028 kprintf("current process = ");
1031 (u_long
)curproc
->p_pid
);
1035 kprintf("current thread = pri %d ", curthread
->td_pri
);
1036 if (curthread
->td_critcount
)
1041 if ((debugger_on_panic
|| db_active
) && kdb_trap(type
, code
, frame
))
1044 kprintf("trap number = %d\n", type
);
1045 if (type
<= MAX_TRAP_MSG
)
1046 panic("%s", trap_msg
[type
]);
1048 panic("unknown/reserved trap");
1052 * Double fault handler. Called when a fault occurs while writing
1053 * a frame for a trap/exception onto the stack. This usually occurs
1054 * when the stack overflows (such is the case with infinite recursion,
1059 in_kstack_guard(register_t rptr
)
1061 thread_t td
= curthread
;
1063 if ((char *)rptr
>= td
->td_kstack
&&
1064 (char *)rptr
< td
->td_kstack
+ PAGE_SIZE
) {
1071 dblfault_handler(struct trapframe
*frame
)
1073 thread_t td
= curthread
;
1075 if (in_kstack_guard(frame
->tf_rsp
) || in_kstack_guard(frame
->tf_rbp
)) {
1076 kprintf("DOUBLE FAULT - KERNEL STACK GUARD HIT!\n");
1077 if (in_kstack_guard(frame
->tf_rsp
))
1078 frame
->tf_rsp
= (register_t
)(td
->td_kstack
+ PAGE_SIZE
);
1079 if (in_kstack_guard(frame
->tf_rbp
))
1080 frame
->tf_rbp
= (register_t
)(td
->td_kstack
+ PAGE_SIZE
);
1082 kprintf("DOUBLE FAULT\n");
1084 kprintf("\nFatal double fault\n");
1085 kprintf("rip = 0x%lx\n", frame
->tf_rip
);
1086 kprintf("rsp = 0x%lx\n", frame
->tf_rsp
);
1087 kprintf("rbp = 0x%lx\n", frame
->tf_rbp
);
1088 /* three separate prints in case of a trap on an unmapped page */
1089 kprintf("cpuid = %d; ", mycpu
->gd_cpuid
);
1090 kprintf("lapic->id = %08x\n", lapic
->id
);
1091 panic("double fault");
1095 * syscall2 - MP aware system call request C handler
1097 * A system call is essentially treated as a trap except that the
1098 * MP lock is not held on entry or return. We are responsible for
1099 * obtaining the MP lock if necessary and for handling ASTs
1100 * (e.g. a task switch) prior to return.
1105 syscall2(struct trapframe
*frame
)
1107 struct thread
*td
= curthread
;
1108 struct proc
*p
= td
->td_proc
;
1109 struct lwp
*lp
= td
->td_lwp
;
1111 struct sysent
*callp
;
1112 register_t orig_tf_rflags
;
1117 int crit_count
= td
->td_critcount
;
1119 int have_mplock
= 0;
1123 union sysunion args
;
1124 register_t
*argsdst
;
1126 mycpu
->gd_cnt
.v_syscall
++;
1129 if (ISPL(frame
->tf_cs
) != SEL_UPL
) {
1136 KTR_LOG(kernentry_syscall
, p
->p_pid
, lp
->lwp_tid
,
1139 userenter(td
, p
); /* lazy raise our priority */
1146 sticks
= (int)td
->td_sticks
;
1147 orig_tf_rflags
= frame
->tf_rflags
;
1150 * Virtual kernel intercept - if a VM context managed by a virtual
1151 * kernel issues a system call the virtual kernel handles it, not us.
1152 * Restore the virtual kernel context and return from its system
1153 * call. The current frame is copied out to the virtual kernel.
1155 if (lp
->lwp_vkernel
&& lp
->lwp_vkernel
->ve
) {
1156 vkernel_trap(lp
, frame
);
1157 error
= EJUSTRETURN
;
1163 * Get the system call parameters and account for time
1165 KASSERT(lp
->lwp_md
.md_regs
== frame
,
1166 ("Frame mismatch %p %p", lp
->lwp_md
.md_regs
, frame
));
1167 params
= (caddr_t
)frame
->tf_rsp
+ sizeof(register_t
);
1168 code
= frame
->tf_rax
;
1170 if (p
->p_sysent
->sv_prepsyscall
) {
1171 (*p
->p_sysent
->sv_prepsyscall
)(
1172 frame
, (int *)(&args
.nosys
.sysmsg
+ 1),
1175 if (code
== SYS_syscall
|| code
== SYS___syscall
) {
1176 code
= frame
->tf_rdi
;
1182 if (p
->p_sysent
->sv_mask
)
1183 code
&= p
->p_sysent
->sv_mask
;
1185 if (code
>= p
->p_sysent
->sv_size
)
1186 callp
= &p
->p_sysent
->sv_table
[0];
1188 callp
= &p
->p_sysent
->sv_table
[code
];
1190 narg
= callp
->sy_narg
& SYF_ARGMASK
;
1193 * On x86_64 we get up to six arguments in registers. The rest are
1194 * on the stack. The first six members of 'struct trapframe' happen
1195 * to be the registers used to pass arguments, in exactly the right
1198 argp
= &frame
->tf_rdi
;
1200 argsdst
= (register_t
*)(&args
.nosys
.sysmsg
+ 1);
1202 * JG can we overflow the space pointed to by 'argsdst'
1203 * either with 'bcopy' or with 'copyin'?
1205 bcopy(argp
, argsdst
, sizeof(register_t
) * regcnt
);
1207 * copyin is MP aware, but the tracing code is not
1209 if (narg
> regcnt
) {
1210 KASSERT(params
!= NULL
, ("copyin args with no params!"));
1211 error
= copyin(params
, &argsdst
[regcnt
],
1212 (narg
- regcnt
) * sizeof(register_t
));
1215 if (KTRPOINT(td
, KTR_SYSCALL
)) {
1216 ktrsyscall(lp
, code
, narg
,
1217 (void *)(&args
.nosys
.sysmsg
+ 1));
1225 if (KTRPOINT(td
, KTR_SYSCALL
)) {
1226 ktrsyscall(lp
, code
, narg
, (void *)(&args
.nosys
.sysmsg
+ 1));
1231 * Default return value is 0 (will be copied to %rax). Double-value
1232 * returns use %rax and %rdx. %rdx is left unchanged for system
1233 * calls which return only one result.
1235 args
.sysmsg_fds
[0] = 0;
1236 args
.sysmsg_fds
[1] = frame
->tf_rdx
;
1239 * The syscall might manipulate the trap frame. If it does it
1240 * will probably return EJUSTRETURN.
1242 args
.sysmsg_frame
= frame
;
1244 STOPEVENT(p
, S_SCE
, narg
); /* MP aware */
1247 * NOTE: All system calls run MPSAFE now. The system call itself
1248 * is responsible for getting the MP lock.
1250 #ifdef SYSCALL_DEBUG
1251 uint64_t tscval
= rdtsc();
1253 error
= (*callp
->sy_call
)(&args
);
1254 #ifdef SYSCALL_DEBUG
1255 tscval
= rdtsc() - tscval
;
1256 tscval
= tscval
* 1000000 / tsc_frequency
;
1257 if (SysCallsWorstCase
[code
] < tscval
)
1258 SysCallsWorstCase
[code
] = tscval
;
1263 * MP SAFE (we may or may not have the MP lock at this point)
1265 //kprintf("SYSMSG %d ", error);
1269 * Reinitialize proc pointer `p' as it may be different
1270 * if this is a child returning from fork syscall.
1273 lp
= curthread
->td_lwp
;
1274 frame
->tf_rax
= args
.sysmsg_fds
[0];
1275 frame
->tf_rdx
= args
.sysmsg_fds
[1];
1276 frame
->tf_rflags
&= ~PSL_C
;
1280 * Reconstruct pc, we know that 'syscall' is 2 bytes.
1281 * We have to do a full context restore so that %r10
1282 * (which was holding the value of %rcx) is restored for
1283 * the next iteration.
1285 if (frame
->tf_err
!= 0 && frame
->tf_err
!= 2)
1286 kprintf("lp %s:%d frame->tf_err is weird %ld\n",
1287 td
->td_comm
, lp
->lwp_proc
->p_pid
, frame
->tf_err
);
1288 frame
->tf_rip
-= frame
->tf_err
;
1289 frame
->tf_r10
= frame
->tf_rcx
;
1294 panic("Unexpected EASYNC return value (for now)");
1297 if (p
->p_sysent
->sv_errsize
) {
1298 if (error
>= p
->p_sysent
->sv_errsize
)
1299 error
= -1; /* XXX */
1301 error
= p
->p_sysent
->sv_errtbl
[error
];
1303 frame
->tf_rax
= error
;
1304 frame
->tf_rflags
|= PSL_C
;
1309 * Traced syscall. trapsignal() should now be MP aware
1311 if (orig_tf_rflags
& PSL_T
) {
1312 frame
->tf_rflags
&= ~PSL_T
;
1313 trapsignal(lp
, SIGTRAP
, TRAP_TRACE
);
1317 * Handle reschedule and other end-of-syscall issues
1319 userret(lp
, frame
, sticks
);
1322 if (KTRPOINT(td
, KTR_SYSRET
)) {
1323 ktrsysret(lp
, code
, error
, args
.sysmsg_result
);
1328 * This works because errno is findable through the
1329 * register set. If we ever support an emulation where this
1330 * is not the case, this code will need to be revisited.
1332 STOPEVENT(p
, S_SCX
, code
);
1336 * Release the MP lock if we had to get it
1340 KTR_LOG(kernentry_syscall_ret
, p
->p_pid
, lp
->lwp_tid
, error
);
1342 KASSERT(crit_count
== td
->td_critcount
,
1343 ("syscall: critical section count mismatch! %d/%d",
1344 crit_count
, td
->td_pri
));
1345 KASSERT(&td
->td_toks_base
== td
->td_toks_stop
,
1346 ("syscall: %ld extra tokens held after trap! syscall %p",
1347 td
->td_toks_stop
- &td
->td_toks_base
,
1353 * NOTE: mplock not held at any point
1356 fork_return(struct lwp
*lp
, struct trapframe
*frame
)
1358 frame
->tf_rax
= 0; /* Child returns zero */
1359 frame
->tf_rflags
&= ~PSL_C
; /* success */
1362 generic_lwp_return(lp
, frame
);
1363 KTR_LOG(kernentry_fork_ret
, lp
->lwp_proc
->p_pid
, lp
->lwp_tid
);
1367 * Simplified back end of syscall(), used when returning from fork()
1368 * directly into user mode.
1370 * This code will return back into the fork trampoline code which then
1373 * NOTE: The mplock is not held at any point.
1376 generic_lwp_return(struct lwp
*lp
, struct trapframe
*frame
)
1378 struct proc
*p
= lp
->lwp_proc
;
1381 * Check for exit-race. If one lwp exits the process concurrent with
1382 * another lwp creating a new thread, the two operations may cross
1383 * each other resulting in the newly-created lwp not receiving a
1386 if (p
->p_flags
& P_WEXIT
) {
1387 kprintf("pid %d (%s) exit race handled\n",
1388 p
->p_pid
, p
->p_comm
);
1389 lwpsignal(p
, lp
, SIGKILL
);
1393 * Newly forked processes are given a kernel priority. We have to
1394 * adjust the priority to a normal user priority and fake entry
1395 * into the kernel (call userenter()) to install a passive release
1396 * function just in case userret() decides to stop the process. This
1397 * can occur when ^Z races a fork. If we do not install the passive
1398 * release function the current process designation will not be
1399 * released when the thread goes to sleep.
1401 lwkt_setpri_self(TDPRI_USER_NORM
);
1402 userenter(lp
->lwp_thread
, p
);
1403 userret(lp
, frame
, 0);
1405 if (KTRPOINT(lp
->lwp_thread
, KTR_SYSRET
))
1406 ktrsysret(lp
, SYS_fork
, 0, 0);
1408 lp
->lwp_flags
|= LWP_PASSIVE_ACQ
;
1410 lp
->lwp_flags
&= ~LWP_PASSIVE_ACQ
;
1414 * If PGEX_FPFAULT is set then set FP_VIRTFP in the PCB to force a T_DNA
1415 * fault (which is then passed back to the virtual kernel) if an attempt is
1416 * made to use the FP unit.
1418 * XXX this is a fairly big hack.
1421 set_vkernel_fp(struct trapframe
*frame
)
1423 struct thread
*td
= curthread
;
1425 if (frame
->tf_xflags
& PGEX_FPFAULT
) {
1426 td
->td_pcb
->pcb_flags
|= FP_VIRTFP
;
1427 if (mdcpu
->gd_npxthread
== td
)
1430 td
->td_pcb
->pcb_flags
&= ~FP_VIRTFP
;
1435 * Called from vkernel_trap() to fixup the vkernel's syscall
1436 * frame for vmspace_ctl() return.
1439 cpu_vkernel_trap(struct trapframe
*frame
, int error
)
1441 frame
->tf_rax
= error
;
1443 frame
->tf_rflags
|= PSL_C
;
1445 frame
->tf_rflags
&= ~PSL_C
;