2 * Copyright (C) 1994, David Greenman
3 * Copyright (c) 1990, 1993
4 * The Regents of the University of California. All rights reserved.
6 * This code is derived from software contributed to Berkeley by
7 * the University of Utah, and William Jolitz.
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 * 3. All advertising materials mentioning features or use of this software
18 * must display the following acknowledgement:
19 * This product includes software developed by the University of
20 * California, Berkeley and its contributors.
21 * 4. Neither the name of the University nor the names of its contributors
22 * may be used to endorse or promote products derived from this software
23 * without specific prior written permission.
25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
28 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
37 * from: @(#)trap.c 7.4 (Berkeley) 5/13/91
38 * $FreeBSD: src/sys/i386/i386/trap.c,v 1.147.2.11 2003/02/27 19:09:59 luoqi Exp $
39 * $DragonFly: src/sys/platform/vkernel/i386/trap.c,v 1.33 2008/05/19 10:28:06 corecode Exp $
43 * 386 Trap and System call handling
50 #include "opt_ktrace.h"
52 #include <sys/param.h>
53 #include <sys/systm.h>
55 #include <sys/pioctl.h>
56 #include <sys/kernel.h>
57 #include <sys/resourcevar.h>
58 #include <sys/signalvar.h>
59 #include <sys/signal2.h>
60 #include <sys/syscall.h>
61 #include <sys/sysctl.h>
62 #include <sys/sysent.h>
64 #include <sys/vmmeter.h>
65 #include <sys/malloc.h>
67 #include <sys/ktrace.h>
70 #include <sys/upcall.h>
71 #include <sys/vkernel.h>
72 #include <sys/sysproto.h>
73 #include <sys/sysunion.h>
74 #include <sys/vmspace.h>
77 #include <vm/vm_param.h>
80 #include <vm/vm_kern.h>
81 #include <vm/vm_map.h>
82 #include <vm/vm_page.h>
83 #include <vm/vm_extern.h>
85 #include <machine/cpu.h>
86 #include <machine/md_var.h>
87 #include <machine/pcb.h>
88 #include <machine/smp.h>
89 #include <machine/tss.h>
90 #include <machine/globaldata.h>
92 #include <machine/vm86.h>
95 #include <sys/msgport2.h>
96 #include <sys/thread2.h>
100 #define MAKEMPSAFE(have_mplock) \
101 if (have_mplock == 0) { \
108 #define MAKEMPSAFE(have_mplock)
112 int (*pmath_emulate
) (struct trapframe
*);
114 extern int trapwrite (unsigned addr
);
116 static int trap_pfault (struct trapframe
*, int, vm_offset_t
);
117 static void trap_fatal (struct trapframe
*, int, vm_offset_t
);
118 void dblfault_handler (void);
121 extern inthand_t
IDTVEC(syscall
);
124 #define MAX_TRAP_MSG 28
125 static char *trap_msg
[] = {
127 "privileged instruction fault", /* 1 T_PRIVINFLT */
129 "breakpoint instruction fault", /* 3 T_BPTFLT */
132 "arithmetic trap", /* 6 T_ARITHTRAP */
133 "system forced exception", /* 7 T_ASTFLT */
135 "general protection fault", /* 9 T_PROTFLT */
136 "trace trap", /* 10 T_TRCTRAP */
138 "page fault", /* 12 T_PAGEFLT */
140 "alignment fault", /* 14 T_ALIGNFLT */
144 "integer divide fault", /* 18 T_DIVIDE */
145 "non-maskable interrupt trap", /* 19 T_NMI */
146 "overflow trap", /* 20 T_OFLOW */
147 "FPU bounds check fault", /* 21 T_BOUND */
148 "FPU device not available", /* 22 T_DNA */
149 "double fault", /* 23 T_DOUBLEFLT */
150 "FPU operand fetch fault", /* 24 T_FPOPFLT */
151 "invalid TSS fault", /* 25 T_TSSFLT */
152 "segment not present fault", /* 26 T_SEGNPFLT */
153 "stack fault", /* 27 T_STKFLT */
154 "machine check trap", /* 28 T_MCHK */
158 static int ddb_on_nmi
= 1;
159 SYSCTL_INT(_machdep
, OID_AUTO
, ddb_on_nmi
, CTLFLAG_RW
,
160 &ddb_on_nmi
, 0, "Go to DDB on NMI");
162 static int panic_on_nmi
= 1;
163 SYSCTL_INT(_machdep
, OID_AUTO
, panic_on_nmi
, CTLFLAG_RW
,
164 &panic_on_nmi
, 0, "Panic on NMI");
165 static int fast_release
;
166 SYSCTL_INT(_machdep
, OID_AUTO
, fast_release
, CTLFLAG_RW
,
167 &fast_release
, 0, "Passive Release was optimal");
168 static int slow_release
;
169 SYSCTL_INT(_machdep
, OID_AUTO
, slow_release
, CTLFLAG_RW
,
170 &slow_release
, 0, "Passive Release was nonoptimal");
172 static int syscall_mpsafe
= 1;
173 SYSCTL_INT(_kern
, OID_AUTO
, syscall_mpsafe
, CTLFLAG_RW
,
174 &syscall_mpsafe
, 0, "Allow MPSAFE marked syscalls to run without BGL");
175 TUNABLE_INT("kern.syscall_mpsafe", &syscall_mpsafe
);
176 static int trap_mpsafe
= 1;
177 SYSCTL_INT(_kern
, OID_AUTO
, trap_mpsafe
, CTLFLAG_RW
,
178 &trap_mpsafe
, 0, "Allow traps to mostly run without the BGL");
179 TUNABLE_INT("kern.trap_mpsafe", &trap_mpsafe
);
182 MALLOC_DEFINE(M_SYSMSG
, "sysmsg", "sysmsg structure");
183 extern int max_sysmsg
;
186 * Passive USER->KERNEL transition. This only occurs if we block in the
187 * kernel while still holding our userland priority. We have to fixup our
188 * priority in order to avoid potential deadlocks before we allow the system
189 * to switch us to another thread.
192 passive_release(struct thread
*td
)
194 struct lwp
*lp
= td
->td_lwp
;
196 td
->td_release
= NULL
;
197 lwkt_setpri_self(TDPRI_KERN_USER
);
198 lp
->lwp_proc
->p_usched
->release_curproc(lp
);
202 * userenter() passively intercepts the thread switch function to increase
203 * the thread priority from a user priority to a kernel priority, reducing
204 * syscall and trap overhead for the case where no switch occurs.
208 userenter(struct thread
*curtd
)
210 curtd
->td_release
= passive_release
;
214 * Handle signals, upcalls, profiling, and other AST's and/or tasks that
215 * must be completed before we can return to or try to return to userland.
217 * Note that td_sticks is a 64 bit quantity, but there's no point doing 64
218 * arithmatic on the delta calculation so the absolute tick values are
219 * truncated to an integer.
222 userret(struct lwp
*lp
, struct trapframe
*frame
, int sticks
)
224 struct proc
*p
= lp
->lwp_proc
;
228 * Charge system time if profiling. Note: times are in microseconds.
229 * This may do a copyout and block, so do it first even though it
230 * means some system time will be charged as user time.
232 if (p
->p_flag
& P_PROFIL
) {
233 addupc_task(p
, frame
->tf_eip
,
234 (u_int
)((int)lp
->lwp_thread
->td_sticks
- sticks
));
239 * If the jungle wants us dead, so be it.
241 if (lp
->lwp_flag
& LWP_WEXIT
) {
244 rel_mplock(); /* NOT REACHED */
248 * Block here if we are in a stopped state.
250 if (p
->p_stat
== SSTOP
) {
258 * Post any pending upcalls
260 if (p
->p_flag
& P_UPCALLPEND
) {
262 p
->p_flag
&= ~P_UPCALLPEND
;
269 * Post any pending signals
271 if ((sig
= CURSIG(lp
)) != 0) {
279 * block here if we are swapped out, but still process signals
280 * (such as SIGKILL). proc0 (the swapin scheduler) is already
281 * aware of our situation, we do not have to wake it up.
283 if (p
->p_flag
& P_SWAPPEDOUT
) {
285 p
->p_flag
|= P_SWAPWAIT
;
287 if (p
->p_flag
& P_SWAPWAIT
)
288 tsleep(p
, PCATCH
, "SWOUT", 0);
289 p
->p_flag
&= ~P_SWAPWAIT
;
295 * Make sure postsig() handled request to restore old signal mask after
296 * running signal handler.
298 KKASSERT((lp
->lwp_flag
& LWP_OLDMASK
) == 0);
302 * Cleanup from userenter and any passive release that might have occured.
303 * We must reclaim the current-process designation before we can return
304 * to usermode. We also handle both LWKT and USER reschedule requests.
307 userexit(struct lwp
*lp
)
309 struct thread
*td
= lp
->lwp_thread
;
310 globaldata_t gd
= td
->td_gd
;
314 * If a user reschedule is requested force a new process to be
315 * chosen by releasing the current process. Our process will only
316 * be chosen again if it has a considerably better priority.
318 if (user_resched_wanted())
319 lp
->lwp_proc
->p_usched
->release_curproc(lp
);
323 * Handle a LWKT reschedule request first. Since our passive release
324 * is still in place we do not have to do anything special.
326 if (lwkt_resched_wanted())
330 * Acquire the current process designation for this user scheduler
331 * on this cpu. This will also handle any user-reschedule requests.
333 lp
->lwp_proc
->p_usched
->acquire_curproc(lp
);
334 /* We may have switched cpus on acquisition */
338 * Reduce our priority in preparation for a return to userland. If
339 * our passive release function was still in place, our priority was
340 * never raised and does not need to be reduced.
342 if (td
->td_release
== NULL
)
343 lwkt_setpri_self(TDPRI_USER_NORM
);
344 td
->td_release
= NULL
;
347 * After reducing our priority there might be other kernel-level
348 * LWKTs that now have a greater priority. Run them as necessary.
349 * We don't have to worry about losing cpu to userland because
350 * we still control the current-process designation and we no longer
351 * have a passive release function installed.
353 if (lwkt_checkpri_self())
358 #if !defined(KTR_KERNENTRY)
359 #define KTR_KERNENTRY KTR_ALL
361 KTR_INFO_MASTER(kernentry
);
362 KTR_INFO(KTR_KERNENTRY
, kernentry
, trap
, 0, "pid=%d, tid=%d, trapno=%d, eva=%p",
363 sizeof(int) + sizeof(int) + sizeof(int) + sizeof(vm_offset_t
));
364 KTR_INFO(KTR_KERNENTRY
, kernentry
, trap_ret
, 0, "pid=%d, tid=%d",
365 sizeof(int) + sizeof(int));
366 KTR_INFO(KTR_KERNENTRY
, kernentry
, syscall
, 0, "pid=%d, tid=%d, call=%d",
367 sizeof(int) + sizeof(int) + sizeof(int));
368 KTR_INFO(KTR_KERNENTRY
, kernentry
, syscall_ret
, 0, "pid=%d, tid=%d, err=%d",
369 sizeof(int) + sizeof(int) + sizeof(int));
370 KTR_INFO(KTR_KERNENTRY
, kernentry
, fork_ret
, 0, "pid=%d, tid=%d",
371 sizeof(int) + sizeof(int));
374 * Exception, fault, and trap interface to the kernel.
375 * This common code is called from assembly language IDT gate entry
376 * routines that prepare a suitable stack frame, and restore this
377 * frame after the exception has been processed.
379 * This function is also called from doreti in an interlock to handle ASTs.
380 * For example: hardwareint->INTROUTINE->(set ast)->doreti->trap
382 * NOTE! We have to retrieve the fault address prior to obtaining the
383 * MP lock because get_mplock() may switch out. YYY cr2 really ought
384 * to be retrieved by the assembly code, not here.
386 * XXX gd_trap_nesting_level currently prevents lwkt_switch() from panicing
387 * if an attempt is made to switch from a fast interrupt or IPI. This is
388 * necessary to properly take fatal kernel traps on SMP machines if
389 * get_mplock() has to block.
393 user_trap(struct trapframe
*frame
)
395 struct globaldata
*gd
= mycpu
;
396 struct thread
*td
= gd
->gd_curthread
;
397 struct lwp
*lp
= td
->td_lwp
;
400 int i
= 0, ucode
= 0, type
, code
;
405 int crit_count
= td
->td_pri
& ~TDPRI_MASK
;
412 * This is a bad kludge to avoid changing the various trapframe
413 * structures. Because we are enabled as a virtual kernel,
414 * the original tf_err field will be passed to us shifted 16
415 * over in the tf_trapno field for T_PAGEFLT.
417 if (frame
->tf_trapno
== T_PAGEFLT
)
422 kprintf("USER_TRAP AT %08x xflags %d trapno %d eva %08x\n",
423 frame
->tf_eip
, frame
->tf_xflags
, frame
->tf_trapno
, eva
);
427 * Everything coming from user mode runs through user_trap,
428 * including system calls.
430 if (frame
->tf_trapno
== T_SYSCALL80
) {
435 KTR_LOG(kernentry_trap
, lp
->lwp_proc
->p_pid
, lp
->lwp_tid
,
436 frame
->tf_trapno
, eva
);
440 eva
= (frame
->tf_trapno
== T_PAGEFLT
? rcr2() : 0);
441 ++gd
->gd_trap_nesting_level
;
442 MAKEMPSAFE(have_mplock
);
443 trap_fatal(frame
, TRUE
, eva
);
444 --gd
->gd_trap_nesting_level
;
449 ++gd
->gd_trap_nesting_level
;
451 if (trap_mpsafe
== 0)
452 MAKEMPSAFE(have_mplock
);
455 --gd
->gd_trap_nesting_level
;
457 #if defined(I586_CPU) && !defined(NO_F00F_HACK)
460 type
= frame
->tf_trapno
;
461 code
= frame
->tf_err
;
465 sticks
= (int)td
->td_sticks
;
466 lp
->lwp_md
.md_regs
= frame
;
469 case T_PRIVINFLT
: /* privileged instruction fault */
474 case T_BPTFLT
: /* bpt instruction fault */
475 case T_TRCTRAP
: /* trace trap */
476 frame
->tf_eflags
&= ~PSL_T
;
480 case T_ARITHTRAP
: /* arithmetic trap */
485 case T_ASTFLT
: /* Allow process switch */
486 mycpu
->gd_cnt
.v_soft
++;
487 if (mycpu
->gd_reqflags
& RQF_AST_OWEUPC
) {
488 atomic_clear_int_nonlocked(&mycpu
->gd_reqflags
,
490 addupc_task(p
, p
->p_prof
.pr_addr
,
496 * The following two traps can happen in
497 * vm86 mode, and, if so, we want to handle
500 case T_PROTFLT
: /* general protection fault */
501 case T_STKFLT
: /* stack fault */
503 if (frame
->tf_eflags
& PSL_VM
) {
504 i
= vm86_emulate((struct vm86frame
*)frame
);
512 case T_SEGNPFLT
: /* segment not present fault */
513 case T_TSSFLT
: /* invalid TSS fault */
514 case T_DOUBLEFLT
: /* double fault */
516 ucode
= code
+ BUS_SEGM_FAULT
;
520 case T_PAGEFLT
: /* page fault */
521 MAKEMPSAFE(have_mplock
);
522 i
= trap_pfault(frame
, TRUE
, eva
);
525 #if defined(I586_CPU) && !defined(NO_F00F_HACK)
535 case T_DIVIDE
: /* integer divide fault */
542 MAKEMPSAFE(have_mplock
);
543 /* machine/parity/power fail/"kitchen sink" faults */
544 if (isa_nmi(code
) == 0) {
547 * NMI can be hooked up to a pushbutton
551 kprintf ("NMI ... going to debugger\n");
552 kdb_trap (type
, 0, frame
);
556 } else if (panic_on_nmi
)
557 panic("NMI indicates hardware failure");
559 #endif /* NISA > 0 */
561 case T_OFLOW
: /* integer overflow fault */
566 case T_BOUND
: /* bounds check fault */
573 * Virtual kernel intercept - pass the DNA exception
574 * to the (emulated) virtual kernel if it asked to handle
575 * it. This occurs when the virtual kernel is holding
576 * onto the FP context for a different emulated
577 * process then the one currently running.
579 * We must still call npxdna() since we may have
580 * saved FP state that the (emulated) virtual kernel
581 * needs to hand over to a different emulated process.
583 if (lp
->lwp_vkernel
&& lp
->lwp_vkernel
->ve
&&
584 (td
->td_pcb
->pcb_flags
& FP_VIRTFP
)
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
599 if (!pmath_emulate
) {
601 ucode
= FPE_FPU_NP_TRAP
;
604 i
= (*pmath_emulate
)(frame
);
606 if (!(frame
->tf_eflags
& PSL_T
))
608 frame
->tf_eflags
&= ~PSL_T
;
611 /* else ucode = emulator_only_knows() XXX */
614 case T_FPOPFLT
: /* FPU operand fetch fault */
619 case T_XMMFLT
: /* SIMD floating-point exception */
626 * Virtual kernel intercept - if the fault is directly related to a
627 * VM context managed by a virtual kernel then let the virtual kernel
630 if (lp
->lwp_vkernel
&& lp
->lwp_vkernel
->ve
) {
631 vkernel_trap(lp
, frame
);
636 * Translate fault for emulators (e.g. Linux)
638 if (*p
->p_sysent
->sv_transtrap
)
639 i
= (*p
->p_sysent
->sv_transtrap
)(i
, type
);
641 MAKEMPSAFE(have_mplock
);
642 trapsignal(lp
, i
, ucode
);
645 if (type
<= MAX_TRAP_MSG
) {
646 uprintf("fatal process exception: %s",
648 if ((type
== T_PAGEFLT
) || (type
== T_PROTFLT
))
649 uprintf(", fault VA = 0x%lx", (u_long
)eva
);
656 KASSERT(td
->td_mpcount
== have_mplock
, ("badmpcount trap/end from %p", (void *)frame
->tf_eip
));
658 userret(lp
, frame
, sticks
);
665 KTR_LOG(kernentry_trap_ret
, lp
->lwp_proc
->p_pid
, lp
->lwp_tid
);
667 KASSERT(crit_count
== (td
->td_pri
& ~TDPRI_MASK
),
668 ("syscall: critical section count mismatch! %d/%d",
669 crit_count
/ TDPRI_CRIT
, td
->td_pri
/ TDPRI_CRIT
));
674 kern_trap(struct trapframe
*frame
)
676 struct globaldata
*gd
= mycpu
;
677 struct thread
*td
= gd
->gd_curthread
;
680 int i
= 0, ucode
= 0, type
, code
;
685 int crit_count
= td
->td_pri
& ~TDPRI_MASK
;
692 if (frame
->tf_trapno
== T_PAGEFLT
)
699 ++gd
->gd_trap_nesting_level
;
700 MAKEMPSAFE(have_mplock
);
701 trap_fatal(frame
, FALSE
, eva
);
702 --gd
->gd_trap_nesting_level
;
707 ++gd
->gd_trap_nesting_level
;
710 if (trap_mpsafe
== 0)
711 MAKEMPSAFE(have_mplock
);
714 --gd
->gd_trap_nesting_level
;
716 type
= frame
->tf_trapno
;
717 code
= frame
->tf_err
;
725 case T_PAGEFLT
: /* page fault */
726 MAKEMPSAFE(have_mplock
);
727 trap_pfault(frame
, FALSE
, eva
);
733 * The kernel may be using npx for copying or other
736 panic("kernel NPX should not happen");
742 case T_PROTFLT
: /* general protection fault */
743 case T_SEGNPFLT
: /* segment not present fault */
745 * Invalid segment selectors and out of bounds
746 * %eip's and %esp's can be set up in user mode.
747 * This causes a fault in kernel mode when the
748 * kernel tries to return to user mode. We want
749 * to get this fault so that we can fix the
750 * problem here and not have to check all the
751 * selectors and pointers when the user changes
754 if (mycpu
->gd_intr_nesting_level
== 0) {
755 if (td
->td_pcb
->pcb_onfault
) {
757 (register_t
)td
->td_pcb
->pcb_onfault
;
765 * PSL_NT can be set in user mode and isn't cleared
766 * automatically when the kernel is entered. This
767 * causes a TSS fault when the kernel attempts to
768 * `iret' because the TSS link is uninitialized. We
769 * want to get this fault so that we can fix the
770 * problem here and not every time the kernel is
773 if (frame
->tf_eflags
& PSL_NT
) {
774 frame
->tf_eflags
&= ~PSL_NT
;
779 case T_TRCTRAP
: /* trace trap */
781 if (frame
->tf_eip
== (int)IDTVEC(syscall
)) {
783 * We've just entered system mode via the
784 * syscall lcall. Continue single stepping
785 * silently until the syscall handler has
790 if (frame
->tf_eip
== (int)IDTVEC(syscall
) + 1) {
792 * The syscall handler has now saved the
793 * flags. Stop single stepping it.
795 frame
->tf_eflags
&= ~PSL_T
;
801 * Ignore debug register trace traps due to
802 * accesses in the user's address space, which
803 * can happen under several conditions such as
804 * if a user sets a watchpoint on a buffer and
805 * then passes that buffer to a system call.
806 * We still want to get TRCTRAPS for addresses
807 * in kernel space because that is useful when
808 * debugging the kernel.
810 if (user_dbreg_trap()) {
812 * Reset breakpoint bits because the
815 load_dr6(rdr6() & 0xfffffff0);
820 * Fall through (TRCTRAP kernel mode, kernel address)
824 * If DDB is enabled, let it handle the debugger trap.
825 * Otherwise, debugger traps "can't happen".
828 MAKEMPSAFE(have_mplock
);
829 if (kdb_trap (type
, 0, frame
))
834 MAKEMPSAFE(have_mplock
);
835 trap_fatal(frame
, FALSE
, eva
);
838 MAKEMPSAFE(have_mplock
);
839 trap_fatal(frame
, FALSE
, eva
);
843 * Ignore this trap generated from a spurious SIGTRAP.
845 * single stepping in / syscalls leads to spurious / SIGTRAP
848 * Haiku (c) 2007 Simon 'corecode' Schubert
854 * Translate fault for emulators (e.g. Linux)
856 if (*p
->p_sysent
->sv_transtrap
)
857 i
= (*p
->p_sysent
->sv_transtrap
)(i
, type
);
859 MAKEMPSAFE(have_mplock
);
860 trapsignal(lp
, i
, ucode
);
863 if (type
<= MAX_TRAP_MSG
) {
864 uprintf("fatal process exception: %s",
866 if ((type
== T_PAGEFLT
) || (type
== T_PROTFLT
))
867 uprintf(", fault VA = 0x%lx", (u_long
)eva
);
879 KASSERT(crit_count
== (td
->td_pri
& ~TDPRI_MASK
),
880 ("syscall: critical section count mismatch! %d/%d",
881 crit_count
/ TDPRI_CRIT
, td
->td_pri
/ TDPRI_CRIT
));
886 trap_pfault(struct trapframe
*frame
, int usermode
, vm_offset_t eva
)
889 struct vmspace
*vm
= NULL
;
893 thread_t td
= curthread
;
894 struct lwp
*lp
= td
->td_lwp
;
896 va
= trunc_page(eva
);
897 if (usermode
== FALSE
) {
899 * This is a fault on kernel virtual memory.
904 * This is a fault on non-kernel virtual memory.
905 * vm is initialized above to NULL. If curproc is NULL
906 * or curproc->p_vmspace is NULL the fault is fatal.
909 vm
= lp
->lwp_vmspace
;
917 if (frame
->tf_xflags
& PGEX_W
)
918 ftype
= VM_PROT_READ
| VM_PROT_WRITE
;
920 ftype
= VM_PROT_READ
;
922 if (map
!= &kernel_map
) {
924 * Keep swapout from messing with us during this
930 * Grow the stack if necessary
932 /* grow_stack returns false only if va falls into
933 * a growable stack region and the stack growth
934 * fails. It returns true if va was not within
935 * a growable stack region, or if the stack
938 if (!grow_stack (lp
->lwp_proc
, va
)) {
944 /* Fault in the user page: */
945 rv
= vm_fault(map
, va
, ftype
,
946 (ftype
& VM_PROT_WRITE
) ? VM_FAULT_DIRTY
952 * Don't have to worry about process locking or stacks in the kernel.
954 rv
= vm_fault(map
, va
, ftype
, VM_FAULT_NORMAL
);
957 if (rv
== KERN_SUCCESS
)
961 if (td
->td_gd
->gd_intr_nesting_level
== 0 &&
962 td
->td_pcb
->pcb_onfault
) {
963 frame
->tf_eip
= (register_t
)td
->td_pcb
->pcb_onfault
;
966 trap_fatal(frame
, usermode
, eva
);
969 return((rv
== KERN_PROTECTION_FAILURE
) ? SIGBUS
: SIGSEGV
);
973 trap_fatal(struct trapframe
*frame
, int usermode
, vm_offset_t eva
)
975 int code
, type
, ss
, esp
;
977 code
= frame
->tf_xflags
;
978 type
= frame
->tf_trapno
;
980 if (type
<= MAX_TRAP_MSG
) {
981 kprintf("\n\nFatal trap %d: %s while in %s mode\n",
982 type
, trap_msg
[type
],
983 (usermode
? "user" : "kernel"));
986 /* two separate prints in case of a trap on an unmapped page */
987 kprintf("mp_lock = %08x; ", mp_lock
);
988 kprintf("cpuid = %d\n", mycpu
->gd_cpuid
);
990 if (type
== T_PAGEFLT
) {
991 kprintf("fault virtual address = 0x%x\n", eva
);
992 kprintf("fault code = %s %s, %s\n",
993 usermode
? "user" : "supervisor",
994 code
& PGEX_W
? "write" : "read",
995 code
& PGEX_P
? "protection violation" : "page not present");
997 kprintf("instruction pointer = 0x%x:0x%x\n",
998 frame
->tf_cs
& 0xffff, frame
->tf_eip
);
1000 ss
= frame
->tf_ss
& 0xffff;
1001 esp
= frame
->tf_esp
;
1003 ss
= GSEL(GDATA_SEL
, SEL_KPL
);
1004 esp
= (int)&frame
->tf_esp
;
1006 kprintf("stack pointer = 0x%x:0x%x\n", ss
, esp
);
1007 kprintf("frame pointer = 0x%x:0x%x\n", ss
, frame
->tf_ebp
);
1008 kprintf("processor eflags = ");
1009 if (frame
->tf_eflags
& PSL_T
)
1010 kprintf("trace trap, ");
1011 if (frame
->tf_eflags
& PSL_I
)
1012 kprintf("interrupt enabled, ");
1013 if (frame
->tf_eflags
& PSL_NT
)
1014 kprintf("nested task, ");
1015 if (frame
->tf_eflags
& PSL_RF
)
1016 kprintf("resume, ");
1018 if (frame
->tf_eflags
& PSL_VM
)
1021 kprintf("IOPL = %d\n", (frame
->tf_eflags
& PSL_IOPL
) >> 12);
1022 kprintf("current process = ");
1024 kprintf("%lu (%s)\n",
1025 (u_long
)curproc
->p_pid
, curproc
->p_comm
?
1026 curproc
->p_comm
: "");
1030 kprintf("current thread = pri %d ", curthread
->td_pri
);
1031 if (curthread
->td_pri
>= TDPRI_CRIT
)
1037 * we probably SHOULD have stopped the other CPUs before now!
1038 * another CPU COULD have been touching cpl at this moment...
1040 kprintf(" <- SMP: XXX");
1049 if ((debugger_on_panic
|| db_active
) && kdb_trap(type
, code
, frame
))
1052 kprintf("trap number = %d\n", type
);
1053 if (type
<= MAX_TRAP_MSG
)
1054 panic("%s", trap_msg
[type
]);
1056 panic("unknown/reserved trap");
1060 * Double fault handler. Called when a fault occurs while writing
1061 * a frame for a trap/exception onto the stack. This usually occurs
1062 * when the stack overflows (such is the case with infinite recursion,
1065 * XXX Note that the current PTD gets replaced by IdlePTD when the
1066 * task switch occurs. This means that the stack that was active at
1067 * the time of the double fault is not available at <kstack> unless
1068 * the machine was idle when the double fault occurred. The downside
1069 * of this is that "trace <ebp>" in ddb won't work.
1072 dblfault_handler(void)
1074 struct mdglobaldata
*gd
= mdcpu
;
1076 kprintf("\nFatal double fault:\n");
1077 kprintf("eip = 0x%x\n", gd
->gd_common_tss
.tss_eip
);
1078 kprintf("esp = 0x%x\n", gd
->gd_common_tss
.tss_esp
);
1079 kprintf("ebp = 0x%x\n", gd
->gd_common_tss
.tss_ebp
);
1081 /* two separate prints in case of a trap on an unmapped page */
1082 kprintf("mp_lock = %08x; ", mp_lock
);
1083 kprintf("cpuid = %d\n", mycpu
->gd_cpuid
);
1085 panic("double fault");
1089 * Compensate for 386 brain damage (missing URKR).
1090 * This is a little simpler than the pagefault handler in trap() because
1091 * it the page tables have already been faulted in and high addresses
1092 * are thrown out early for other reasons.
1095 trapwrite(unsigned addr
)
1102 va
= trunc_page((vm_offset_t
)addr
);
1104 * XXX - MAX is END. Changed > to >= for temp. fix.
1106 if (va
>= VM_MAX_USER_ADDRESS
)
1109 lp
= curthread
->td_lwp
;
1110 vm
= lp
->lwp_vmspace
;
1112 PHOLD(lp
->lwp_proc
);
1114 if (!grow_stack (lp
->lwp_proc
, va
)) {
1115 PRELE(lp
->lwp_proc
);
1120 * fault the data page
1122 rv
= vm_fault(&vm
->vm_map
, va
, VM_PROT_WRITE
, VM_FAULT_DIRTY
);
1124 PRELE(lp
->lwp_proc
);
1126 if (rv
!= KERN_SUCCESS
)
1133 * syscall2 - MP aware system call request C handler
1135 * A system call is essentially treated as a trap except that the
1136 * MP lock is not held on entry or return. We are responsible for
1137 * obtaining the MP lock if necessary and for handling ASTs
1138 * (e.g. a task switch) prior to return.
1140 * In general, only simple access and manipulation of curproc and
1141 * the current stack is allowed without having to hold MP lock.
1143 * MPSAFE - note that large sections of this routine are run without
1148 syscall2(struct trapframe
*frame
)
1150 struct thread
*td
= curthread
;
1151 struct proc
*p
= td
->td_proc
;
1152 struct lwp
*lp
= td
->td_lwp
;
1154 struct sysent
*callp
;
1155 register_t orig_tf_eflags
;
1160 int crit_count
= td
->td_pri
& ~TDPRI_MASK
;
1163 int have_mplock
= 0;
1166 union sysunion args
;
1168 KTR_LOG(kernentry_syscall
, lp
->lwp_proc
->p_pid
, lp
->lwp_tid
,
1172 KASSERT(td
->td_mpcount
== 0, ("badmpcount syscall2 from %p", (void *)frame
->tf_eip
));
1173 if (syscall_mpsafe
== 0)
1174 MAKEMPSAFE(have_mplock
);
1176 userenter(td
); /* lazy raise our priority */
1181 sticks
= (int)td
->td_sticks
;
1182 orig_tf_eflags
= frame
->tf_eflags
;
1185 * Virtual kernel intercept - if a VM context managed by a virtual
1186 * kernel issues a system call the virtual kernel handles it, not us.
1187 * Restore the virtual kernel context and return from its system
1188 * call. The current frame is copied out to the virtual kernel.
1190 if (lp
->lwp_vkernel
&& lp
->lwp_vkernel
->ve
) {
1191 error
= vkernel_trap(lp
, frame
);
1192 frame
->tf_eax
= error
;
1194 frame
->tf_eflags
|= PSL_C
;
1195 error
= EJUSTRETURN
;
1200 * Get the system call parameters and account for time
1202 lp
->lwp_md
.md_regs
= frame
;
1203 params
= (caddr_t
)frame
->tf_esp
+ sizeof(int);
1204 code
= frame
->tf_eax
;
1206 if (p
->p_sysent
->sv_prepsyscall
) {
1207 (*p
->p_sysent
->sv_prepsyscall
)(
1208 frame
, (int *)(&args
.nosys
.sysmsg
+ 1),
1212 * Need to check if this is a 32 bit or 64 bit syscall.
1213 * fuword is MP aware.
1215 if (code
== SYS_syscall
) {
1217 * Code is first argument, followed by actual args.
1219 code
= fuword(params
);
1220 params
+= sizeof(int);
1221 } else if (code
== SYS___syscall
) {
1223 * Like syscall, but code is a quad, so as to maintain
1224 * quad alignment for the rest of the arguments.
1226 code
= fuword(params
);
1227 params
+= sizeof(quad_t
);
1231 code
&= p
->p_sysent
->sv_mask
;
1232 if (code
>= p
->p_sysent
->sv_size
)
1233 callp
= &p
->p_sysent
->sv_table
[0];
1235 callp
= &p
->p_sysent
->sv_table
[code
];
1237 narg
= callp
->sy_narg
& SYF_ARGMASK
;
1240 * copyin is MP aware, but the tracing code is not
1242 if (narg
&& params
) {
1243 error
= copyin(params
, (caddr_t
)(&args
.nosys
.sysmsg
+ 1),
1244 narg
* sizeof(register_t
));
1247 if (KTRPOINT(td
, KTR_SYSCALL
)) {
1248 MAKEMPSAFE(have_mplock
);
1250 ktrsyscall(lp
, code
, narg
,
1251 (void *)(&args
.nosys
.sysmsg
+ 1));
1259 if (KTRPOINT(td
, KTR_SYSCALL
)) {
1260 MAKEMPSAFE(have_mplock
);
1261 ktrsyscall(lp
, code
, narg
, (void *)(&args
.nosys
.sysmsg
+ 1));
1266 * For traditional syscall code edx is left untouched when 32 bit
1267 * results are returned. Since edx is loaded from fds[1] when the
1268 * system call returns we pre-set it here.
1270 args
.sysmsg_fds
[0] = 0;
1271 args
.sysmsg_fds
[1] = frame
->tf_edx
;
1274 * The syscall might manipulate the trap frame. If it does it
1275 * will probably return EJUSTRETURN.
1277 args
.sysmsg_frame
= frame
;
1279 STOPEVENT(p
, S_SCE
, narg
); /* MP aware */
1283 * Try to run the syscall without the MP lock if the syscall
1284 * is MP safe. We have to obtain the MP lock no matter what if
1287 if ((callp
->sy_narg
& SYF_MPSAFE
) == 0)
1288 MAKEMPSAFE(have_mplock
);
1291 error
= (*callp
->sy_call
)(&args
);
1294 kprintf("system call %d returned %d\n", code
, error
);
1299 * MP SAFE (we may or may not have the MP lock at this point)
1304 * Reinitialize proc pointer `p' as it may be different
1305 * if this is a child returning from fork syscall.
1308 lp
= curthread
->td_lwp
;
1309 frame
->tf_eax
= args
.sysmsg_fds
[0];
1310 frame
->tf_edx
= args
.sysmsg_fds
[1];
1311 frame
->tf_eflags
&= ~PSL_C
;
1315 * Reconstruct pc, assuming lcall $X,y is 7 bytes,
1316 * int 0x80 is 2 bytes. We saved this in tf_err.
1318 frame
->tf_eip
-= frame
->tf_err
;
1323 panic("Unexpected EASYNC return value (for now)");
1326 if (p
->p_sysent
->sv_errsize
) {
1327 if (error
>= p
->p_sysent
->sv_errsize
)
1328 error
= -1; /* XXX */
1330 error
= p
->p_sysent
->sv_errtbl
[error
];
1332 frame
->tf_eax
= error
;
1333 frame
->tf_eflags
|= PSL_C
;
1338 * Traced syscall. trapsignal() is not MP aware.
1340 if ((orig_tf_eflags
& PSL_T
) /*&& !(orig_tf_eflags & PSL_VM)*/) {
1341 MAKEMPSAFE(have_mplock
);
1342 frame
->tf_eflags
&= ~PSL_T
;
1343 trapsignal(lp
, SIGTRAP
, 0);
1347 * Handle reschedule and other end-of-syscall issues
1349 userret(lp
, frame
, sticks
);
1352 if (KTRPOINT(td
, KTR_SYSRET
)) {
1353 MAKEMPSAFE(have_mplock
);
1354 ktrsysret(lp
, code
, error
, args
.sysmsg_result
);
1359 * This works because errno is findable through the
1360 * register set. If we ever support an emulation where this
1361 * is not the case, this code will need to be revisited.
1363 STOPEVENT(p
, S_SCX
, code
);
1368 * Release the MP lock if we had to get it
1370 KASSERT(td
->td_mpcount
== have_mplock
,
1371 ("badmpcount syscall2/end from %p", (void *)frame
->tf_eip
));
1375 KTR_LOG(kernentry_syscall_ret
, lp
->lwp_proc
->p_pid
, lp
->lwp_tid
, error
);
1377 KASSERT(crit_count
== (td
->td_pri
& ~TDPRI_MASK
),
1378 ("syscall: critical section count mismatch! %d/%d",
1379 crit_count
/ TDPRI_CRIT
, td
->td_pri
/ TDPRI_CRIT
));
1384 fork_return(struct lwp
*lp
, struct trapframe
*frame
)
1386 frame
->tf_eax
= 0; /* Child returns zero */
1387 frame
->tf_eflags
&= ~PSL_C
; /* success */
1390 generic_lwp_return(lp
, frame
);
1391 KTR_LOG(kernentry_fork_ret
, lp
->lwp_proc
->p_pid
, lp
->lwp_tid
);
1395 * Simplified back end of syscall(), used when returning from fork()
1396 * or lwp_create() directly into user mode. MP lock is held on entry and
1397 * should be released on return. This code will return back into the fork
1398 * trampoline code which then runs doreti.
1401 generic_lwp_return(struct lwp
*lp
, struct trapframe
*frame
)
1403 struct proc
*p
= lp
->lwp_proc
;
1406 * Newly forked processes are given a kernel priority. We have to
1407 * adjust the priority to a normal user priority and fake entry
1408 * into the kernel (call userenter()) to install a passive release
1409 * function just in case userret() decides to stop the process. This
1410 * can occur when ^Z races a fork. If we do not install the passive
1411 * release function the current process designation will not be
1412 * released when the thread goes to sleep.
1414 lwkt_setpri_self(TDPRI_USER_NORM
);
1415 userenter(lp
->lwp_thread
);
1416 userret(lp
, frame
, 0);
1418 if (KTRPOINT(lp
->lwp_thread
, KTR_SYSRET
))
1419 ktrsysret(lp
, SYS_fork
, 0, 0);
1421 p
->p_flag
|= P_PASSIVE_ACQ
;
1423 p
->p_flag
&= ~P_PASSIVE_ACQ
;
1425 KKASSERT(lp
->lwp_thread
->td_mpcount
== 1);
1431 * doreti has turned into this. The frame is directly on the stack. We
1432 * pull everything else we need (fpu and tls context) from the current
1435 * Note on fpu interactions: In a virtual kernel, the fpu context for
1436 * an emulated user mode process is not shared with the virtual kernel's
1437 * fpu context, so we only have to 'stack' fpu contexts within the virtual
1438 * kernel itself, and not even then since the signal() contexts that we care
1439 * about save and restore the FPU state (I think anyhow).
1441 * vmspace_ctl() returns an error only if it had problems instaling the
1442 * context we supplied or problems copying data to/from our VM space.
1445 go_user(struct intrframe
*frame
)
1447 struct trapframe
*tf
= (void *)&frame
->if_gs
;
1451 * Interrupts may be disabled on entry, make sure all signals
1452 * can be received before beginning our loop.
1457 * Switch to the current simulated user process, then call
1458 * user_trap() when we break out of it (usually due to a signal).
1462 * Tell the real kernel whether it is ok to use the FP
1465 if (mdcpu
->gd_npxthread
== curthread
) {
1466 tf
->tf_xflags
&= ~PGEX_FPFAULT
;
1468 tf
->tf_xflags
|= PGEX_FPFAULT
;
1472 * Run emulated user process context. This call interlocks
1473 * with new mailbox signals.
1475 * Set PGEX_U unconditionally, indicating a user frame (the
1476 * bit is normally set only by T_PAGEFLT).
1478 r
= vmspace_ctl(&curproc
->p_vmspace
->vm_pmap
, VMSPACE_CTL_RUN
,
1479 tf
, &curthread
->td_savevext
);
1480 frame
->if_xflags
|= PGEX_U
;
1482 kprintf("GO USER %d trap %d EVA %08x EIP %08x ESP %08x XFLAGS %02x/%02x\n",
1483 r
, tf
->tf_trapno
, tf
->tf_err
, tf
->tf_eip
, tf
->tf_esp
,
1484 tf
->tf_xflags
, frame
->if_xflags
);
1488 panic("vmspace_ctl failed");
1490 if (tf
->tf_trapno
) {
1492 } else if (mycpu
->gd_reqflags
& RQF_AST_MASK
) {
1493 tf
->tf_trapno
= T_ASTFLT
;
1502 * If PGEX_FPFAULT is set then set FP_VIRTFP in the PCB to force a T_DNA
1503 * fault (which is then passed back to the virtual kernel) if an attempt is
1504 * made to use the FP unit.
1506 * XXX this is a fairly big hack.
1509 set_vkernel_fp(struct trapframe
*frame
)
1511 struct thread
*td
= curthread
;
1513 if (frame
->tf_xflags
& PGEX_FPFAULT
) {
1514 td
->td_pcb
->pcb_flags
|= FP_VIRTFP
;
1515 if (mdcpu
->gd_npxthread
== td
)
1518 td
->td_pcb
->pcb_flags
&= ~FP_VIRTFP
;