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
48 #include "opt_ktrace.h"
50 #include <machine/frame.h>
51 #include <sys/param.h>
52 #include <sys/systm.h>
53 #include <sys/kernel.h>
55 #include <sys/pioctl.h>
56 #include <sys/types.h>
57 #include <sys/signal2.h>
58 #include <sys/syscall.h>
59 #include <sys/sysctl.h>
60 #include <sys/sysent.h>
61 #include <sys/systm.h>
63 #include <sys/ktrace.h>
66 #include <sys/sysmsg.h>
67 #include <sys/sysproto.h>
68 #include <sys/sysunion.h>
72 #include <vm/vm_extern.h>
73 #include <vm/vm_kern.h>
74 #include <vm/vm_param.h>
75 #include <machine/cpu.h>
76 #include <machine/pcb.h>
77 #include <machine/smp.h>
78 #include <machine/thread.h>
79 #include <machine/vmparam.h>
80 #include <machine/md_var.h>
81 #include <machine_base/isa/intr_machdep.h>
85 #include <sys/thread2.h>
86 #include <sys/mplock2.h>
90 #define MAKEMPSAFE(have_mplock) \
91 if (have_mplock == 0) { \
98 #define MAKEMPSAFE(have_mplock)
102 extern void trap(struct trapframe
*frame
);
104 static int trap_pfault(struct trapframe
*, int);
105 static void trap_fatal(struct trapframe
*, vm_offset_t
);
106 void dblfault_handler(struct trapframe
*frame
);
108 #define MAX_TRAP_MSG 30
109 static char *trap_msg
[] = {
111 "privileged instruction fault", /* 1 T_PRIVINFLT */
113 "breakpoint instruction fault", /* 3 T_BPTFLT */
116 "arithmetic trap", /* 6 T_ARITHTRAP */
117 "system forced exception", /* 7 T_ASTFLT */
119 "general protection fault", /* 9 T_PROTFLT */
120 "trace trap", /* 10 T_TRCTRAP */
122 "page fault", /* 12 T_PAGEFLT */
124 "alignment fault", /* 14 T_ALIGNFLT */
128 "integer divide fault", /* 18 T_DIVIDE */
129 "non-maskable interrupt trap", /* 19 T_NMI */
130 "overflow trap", /* 20 T_OFLOW */
131 "FPU bounds check fault", /* 21 T_BOUND */
132 "FPU device not available", /* 22 T_DNA */
133 "double fault", /* 23 T_DOUBLEFLT */
134 "FPU operand fetch fault", /* 24 T_FPOPFLT */
135 "invalid TSS fault", /* 25 T_TSSFLT */
136 "segment not present fault", /* 26 T_SEGNPFLT */
137 "stack fault", /* 27 T_STKFLT */
138 "machine check trap", /* 28 T_MCHK */
139 "SIMD floating-point exception", /* 29 T_XMMFLT */
140 "reserved (unknown) fault", /* 30 T_RESERVED */
144 static int ddb_on_nmi
= 1;
145 SYSCTL_INT(_machdep
, OID_AUTO
, ddb_on_nmi
, CTLFLAG_RW
,
146 &ddb_on_nmi
, 0, "Go to DDB on NMI");
148 static int panic_on_nmi
= 1;
149 SYSCTL_INT(_machdep
, OID_AUTO
, panic_on_nmi
, CTLFLAG_RW
,
150 &panic_on_nmi
, 0, "Panic on NMI");
151 static int fast_release
;
152 SYSCTL_INT(_machdep
, OID_AUTO
, fast_release
, CTLFLAG_RW
,
153 &fast_release
, 0, "Passive Release was optimal");
154 static int slow_release
;
155 SYSCTL_INT(_machdep
, OID_AUTO
, slow_release
, CTLFLAG_RW
,
156 &slow_release
, 0, "Passive Release was nonoptimal");
158 static int syscall_mpsafe
= 1;
159 SYSCTL_INT(_kern
, OID_AUTO
, syscall_mpsafe
, CTLFLAG_RW
,
160 &syscall_mpsafe
, 0, "Allow MPSAFE marked syscalls to run without BGL");
161 TUNABLE_INT("kern.syscall_mpsafe", &syscall_mpsafe
);
162 static int trap_mpsafe
= 1;
163 SYSCTL_INT(_kern
, OID_AUTO
, trap_mpsafe
, CTLFLAG_RW
,
164 &trap_mpsafe
, 0, "Allow traps to mostly run without the BGL");
165 TUNABLE_INT("kern.trap_mpsafe", &trap_mpsafe
);
169 * Passively intercepts the thread switch function to increase
170 * the thread priority from a user priority to a kernel priority, reducing
171 * syscall and trap overhead for the case where no switch occurs.
173 * Synchronizes td_ucred with p_ucred. This is used by system calls,
174 * signal handling, faults, AST traps, and anything else that enters the
175 * kernel from userland and provides the kernel with a stable read-only
176 * copy of the process ucred.
179 userenter(struct thread
*curtd
, struct proc
*curp
)
184 curtd
->td_release
= lwkt_passive_release
;
186 if (curtd
->td_ucred
!= curp
->p_ucred
) {
187 ncred
= crhold(curp
->p_ucred
);
188 ocred
= curtd
->td_ucred
;
189 curtd
->td_ucred
= ncred
;
196 * Handle signals, upcalls, profiling, and other AST's and/or tasks that
197 * must be completed before we can return to or try to return to userland.
199 * Note that td_sticks is a 64 bit quantity, but there's no point doing 64
200 * arithmatic on the delta calculation so the absolute tick values are
201 * truncated to an integer.
204 userret(struct lwp
*lp
, struct trapframe
*frame
, int sticks
)
206 struct proc
*p
= lp
->lwp_proc
;
210 * Charge system time if profiling. Note: times are in microseconds.
211 * This may do a copyout and block, so do it first even though it
212 * means some system time will be charged as user time.
214 if (p
->p_flag
& P_PROFIL
) {
215 addupc_task(p
, frame
->tf_rip
,
216 (u_int
)((int)lp
->lwp_thread
->td_sticks
- sticks
));
221 * If the jungle wants us dead, so be it.
223 if (lp
->lwp_flag
& LWP_WEXIT
) {
226 rel_mplock(); /* NOT REACHED */
230 * Block here if we are in a stopped state.
232 if (p
->p_stat
== SSTOP
) {
240 * Post any pending upcalls. If running a virtual kernel be sure
241 * to restore the virtual kernel's vmspace before posting the upcall.
243 if (p
->p_flag
& P_UPCALLPEND
) {
244 p
->p_flag
&= ~P_UPCALLPEND
;
252 * Post any pending signals. If running a virtual kernel be sure
253 * to restore the virtual kernel's vmspace before posting the signal.
255 if ((sig
= CURSIG_TRACE(lp
)) != 0) {
263 * block here if we are swapped out, but still process signals
264 * (such as SIGKILL). proc0 (the swapin scheduler) is already
265 * aware of our situation, we do not have to wake it up.
267 if (p
->p_flag
& P_SWAPPEDOUT
) {
269 p
->p_flag
|= P_SWAPWAIT
;
271 if (p
->p_flag
& P_SWAPWAIT
)
272 tsleep(p
, PCATCH
, "SWOUT", 0);
273 p
->p_flag
&= ~P_SWAPWAIT
;
279 * Make sure postsig() handled request to restore old signal mask after
280 * running signal handler.
282 KKASSERT((lp
->lwp_flag
& LWP_OLDMASK
) == 0);
286 * Cleanup from userenter and any passive release that might have occured.
287 * We must reclaim the current-process designation before we can return
288 * to usermode. We also handle both LWKT and USER reschedule requests.
291 userexit(struct lwp
*lp
)
293 struct thread
*td
= lp
->lwp_thread
;
294 /* globaldata_t gd = td->td_gd;*/
297 * Handle stop requests at kernel priority. Any requests queued
298 * after this loop will generate another AST.
300 while (lp
->lwp_proc
->p_stat
== SSTOP
) {
307 * Reduce our priority in preparation for a return to userland. If
308 * our passive release function was still in place, our priority was
309 * never raised and does not need to be reduced.
311 lwkt_passive_recover(td
);
314 * Become the current user scheduled process if we aren't already,
315 * and deal with reschedule requests and other factors.
317 lp
->lwp_proc
->p_usched
->acquire_curproc(lp
);
318 /* WARNING: we may have migrated cpu's */
319 /* gd = td->td_gd; */
322 #if !defined(KTR_KERNENTRY)
323 #define KTR_KERNENTRY KTR_ALL
325 KTR_INFO_MASTER(kernentry
);
326 KTR_INFO(KTR_KERNENTRY
, kernentry
, trap
, 0, "STR",
327 sizeof(long) + sizeof(long) + sizeof(long) + sizeof(vm_offset_t
));
328 KTR_INFO(KTR_KERNENTRY
, kernentry
, trap_ret
, 0, "STR",
329 sizeof(long) + sizeof(long));
330 KTR_INFO(KTR_KERNENTRY
, kernentry
, syscall
, 0, "STR",
331 sizeof(long) + sizeof(long) + sizeof(long));
332 KTR_INFO(KTR_KERNENTRY
, kernentry
, syscall_ret
, 0, "STR",
333 sizeof(long) + sizeof(long) + sizeof(long));
334 KTR_INFO(KTR_KERNENTRY
, kernentry
, fork_ret
, 0, "STR",
335 sizeof(long) + sizeof(long));
338 * Exception, fault, and trap interface to the kernel.
339 * This common code is called from assembly language IDT gate entry
340 * routines that prepare a suitable stack frame, and restore this
341 * frame after the exception has been processed.
343 * This function is also called from doreti in an interlock to handle ASTs.
344 * For example: hardwareint->INTROUTINE->(set ast)->doreti->trap
346 * NOTE! We have to retrieve the fault address prior to obtaining the
347 * MP lock because get_mplock() may switch out. YYY cr2 really ought
348 * to be retrieved by the assembly code, not here.
350 * XXX gd_trap_nesting_level currently prevents lwkt_switch() from panicing
351 * if an attempt is made to switch from a fast interrupt or IPI. This is
352 * necessary to properly take fatal kernel traps on SMP machines if
353 * get_mplock() has to block.
357 trap(struct trapframe
*frame
)
359 struct globaldata
*gd
= mycpu
;
360 struct thread
*td
= gd
->gd_curthread
;
361 struct lwp
*lp
= td
->td_lwp
;
364 int i
= 0, ucode
= 0, type
, code
;
369 int crit_count
= td
->td_pri
& ~TDPRI_MASK
;
377 kprintf0("\"%s\" type=%ld\n",
378 trap_msg
[frame
->tf_trapno
], frame
->tf_trapno
);
379 kprintf0(" rip=%lx rsp=%lx\n", frame
->tf_rip
, frame
->tf_rsp
);
380 kprintf0(" err=%lx addr=%lx\n", frame
->tf_err
, frame
->tf_addr
);
381 kprintf0(" cs=%lx ss=%lx rflags=%lx\n", (unsigned long)frame
->tf_cs
, (unsigned long)frame
->tf_ss
, frame
->tf_rflags
);
386 ++gd
->gd_trap_nesting_level
;
387 MAKEMPSAFE(have_mplock
);
388 trap_fatal(frame
, frame
->tf_addr
);
389 --gd
->gd_trap_nesting_level
;
395 eva
= (frame
->tf_trapno
== T_PAGEFLT
? frame
->tf_addr
: 0);
396 ++gd
->gd_trap_nesting_level
;
397 MAKEMPSAFE(have_mplock
);
398 trap_fatal(frame
, eva
);
399 --gd
->gd_trap_nesting_level
;
407 if (trap_mpsafe
== 0) {
408 ++gd
->gd_trap_nesting_level
;
409 MAKEMPSAFE(have_mplock
);
410 --gd
->gd_trap_nesting_level
;
414 if ((frame
->tf_rflags
& PSL_I
) == 0) {
416 * Buggy application or kernel code has disabled interrupts
417 * and then trapped. Enabling interrupts now is wrong, but
418 * it is better than running with interrupts disabled until
419 * they are accidentally enabled later.
421 type
= frame
->tf_trapno
;
422 if (ISPL(frame
->tf_cs
) == SEL_UPL
) {
423 MAKEMPSAFE(have_mplock
);
424 /* JG curproc can be NULL */
426 "pid %ld (%s): trap %d with interrupts disabled\n",
427 (long)curproc
->p_pid
, curproc
->p_comm
, type
);
428 } else if (type
!= T_NMI
&& type
!= T_BPTFLT
&&
431 * XXX not quite right, since this may be for a
432 * multiple fault in user mode.
434 MAKEMPSAFE(have_mplock
);
435 kprintf("kernel trap %d with interrupts disabled\n",
441 type
= frame
->tf_trapno
;
442 code
= frame
->tf_err
;
444 if (ISPL(frame
->tf_cs
) == SEL_UPL
) {
447 KTR_LOG(kernentry_trap
, p
->p_pid
, lp
->lwp_tid
,
448 frame
->tf_trapno
, eva
);
452 sticks
= (int)td
->td_sticks
;
453 lp
->lwp_md
.md_regs
= frame
;
456 case T_PRIVINFLT
: /* privileged instruction fault */
461 case T_BPTFLT
: /* bpt instruction fault */
462 case T_TRCTRAP
: /* trace trap */
463 frame
->tf_rflags
&= ~PSL_T
;
468 case T_ARITHTRAP
: /* arithmetic trap */
481 case T_ASTFLT
: /* Allow process switch */
482 mycpu
->gd_cnt
.v_soft
++;
483 if (mycpu
->gd_reqflags
& RQF_AST_OWEUPC
) {
484 atomic_clear_int_nonlocked(&mycpu
->gd_reqflags
,
486 addupc_task(p
, p
->p_prof
.pr_addr
,
491 case T_PROTFLT
: /* general protection fault */
495 case T_SEGNPFLT
: /* segment not present fault */
499 case T_TSSFLT
: /* invalid TSS fault */
500 case T_DOUBLEFLT
: /* double fault */
505 ucode
= code
+ BUS_SEGM_FAULT
; /* XXX: ???*/
511 case T_PAGEFLT
: /* page fault */
512 MAKEMPSAFE(have_mplock
);
513 i
= trap_pfault(frame
, TRUE
);
514 if (frame
->tf_rip
== 0)
515 kprintf("T_PAGEFLT: Warning %%rip == 0!\n");
530 case T_DIVIDE
: /* integer divide fault */
536 MAKEMPSAFE(have_mplock
);
537 /* machine/parity/power fail/"kitchen sink" faults */
538 if (isa_nmi(code
) == 0) {
541 * NMI can be hooked up to a pushbutton
545 kprintf ("NMI ... going to debugger\n");
546 kdb_trap(type
, 0, frame
);
550 } else if (panic_on_nmi
)
551 panic("NMI indicates hardware failure");
554 case T_OFLOW
: /* integer overflow fault */
559 case T_BOUND
: /* bounds check fault */
566 * Virtual kernel intercept - pass the DNA exception
567 * to the virtual kernel if it asked to handle it.
568 * This occurs when the virtual kernel is holding
569 * onto the FP context for a different emulated
570 * process then the one currently running.
572 * We must still call npxdna() since we may have
573 * saved FP state that the virtual kernel needs
574 * to hand over to a different emulated process.
576 if (lp
->lwp_vkernel
&& lp
->lwp_vkernel
->ve
&&
577 (td
->td_pcb
->pcb_flags
& FP_VIRTFP
)
584 * The kernel may have switched out the FP unit's
585 * state, causing the user process to take a fault
586 * when it tries to use the FP unit. Restore the
592 ucode
= FPE_FPU_NP_TRAP
;
595 case T_FPOPFLT
: /* FPU operand fetch fault */
600 case T_XMMFLT
: /* SIMD floating-point exception */
609 case T_PAGEFLT
: /* page fault */
610 MAKEMPSAFE(have_mplock
);
611 trap_pfault(frame
, FALSE
);
616 * The kernel is apparently using fpu for copying.
617 * XXX this should be fatal unless the kernel has
618 * registered such use.
624 case T_STKFLT
: /* stack fault */
627 case T_PROTFLT
: /* general protection fault */
628 case T_SEGNPFLT
: /* segment not present fault */
630 * Invalid segment selectors and out of bounds
631 * %rip's and %rsp's can be set up in user mode.
632 * This causes a fault in kernel mode when the
633 * kernel tries to return to user mode. We want
634 * to get this fault so that we can fix the
635 * problem here and not have to check all the
636 * selectors and pointers when the user changes
639 kprintf("trap.c line %d\n", __LINE__
);
640 if (mycpu
->gd_intr_nesting_level
== 0) {
641 if (td
->td_pcb
->pcb_onfault
) {
642 frame
->tf_rip
= (register_t
)
643 td
->td_pcb
->pcb_onfault
;
646 if (frame
->tf_rip
== (long)doreti_iret
) {
647 frame
->tf_rip
= (long)doreti_iret_fault
;
655 * PSL_NT can be set in user mode and isn't cleared
656 * automatically when the kernel is entered. This
657 * causes a TSS fault when the kernel attempts to
658 * `iret' because the TSS link is uninitialized. We
659 * want to get this fault so that we can fix the
660 * problem here and not every time the kernel is
663 if (frame
->tf_rflags
& PSL_NT
) {
664 frame
->tf_rflags
&= ~PSL_NT
;
669 case T_TRCTRAP
: /* trace trap */
671 if (frame
->tf_rip
== (int)IDTVEC(syscall
)) {
673 * We've just entered system mode via the
674 * syscall lcall. Continue single stepping
675 * silently until the syscall handler has
680 if (frame
->tf_rip
== (int)IDTVEC(syscall
) + 1) {
682 * The syscall handler has now saved the
683 * flags. Stop single stepping it.
685 frame
->tf_rflags
&= ~PSL_T
;
691 * Ignore debug register trace traps due to
692 * accesses in the user's address space, which
693 * can happen under several conditions such as
694 * if a user sets a watchpoint on a buffer and
695 * then passes that buffer to a system call.
696 * We still want to get TRCTRAPS for addresses
697 * in kernel space because that is useful when
698 * debugging the kernel.
701 if (user_dbreg_trap()) {
703 * Reset breakpoint bits because the
706 /* XXX check upper bits here */
707 load_dr6(rdr6() & 0xfffffff0);
712 * FALLTHROUGH (TRCTRAP kernel mode, kernel address)
716 * If DDB is enabled, let it handle the debugger trap.
717 * Otherwise, debugger traps "can't happen".
721 MAKEMPSAFE(have_mplock
);
722 if (kdb_trap(type
, 0, frame
))
728 MAKEMPSAFE(have_mplock
);
729 /* machine/parity/power fail/"kitchen sink" faults */
731 if (isa_nmi(code
) == 0) {
734 * NMI can be hooked up to a pushbutton
738 kprintf ("NMI ... going to debugger\n");
739 kdb_trap(type
, 0, frame
);
743 } else if (panic_on_nmi
== 0)
746 #endif /* NISA > 0 */
748 MAKEMPSAFE(have_mplock
);
749 trap_fatal(frame
, 0);
754 * Virtual kernel intercept - if the fault is directly related to a
755 * VM context managed by a virtual kernel then let the virtual kernel
758 if (lp
->lwp_vkernel
&& lp
->lwp_vkernel
->ve
) {
759 vkernel_trap(lp
, frame
);
764 * Virtual kernel intercept - if the fault is directly related to a
765 * VM context managed by a virtual kernel then let the virtual kernel
768 if (lp
->lwp_vkernel
&& lp
->lwp_vkernel
->ve
) {
769 vkernel_trap(lp
, frame
);
774 * Translate fault for emulators (e.g. Linux)
776 if (*p
->p_sysent
->sv_transtrap
)
777 i
= (*p
->p_sysent
->sv_transtrap
)(i
, type
);
779 MAKEMPSAFE(have_mplock
);
780 trapsignal(lp
, i
, ucode
);
783 if (type
<= MAX_TRAP_MSG
) {
784 uprintf("fatal process exception: %s",
786 if ((type
== T_PAGEFLT
) || (type
== T_PROTFLT
))
787 uprintf(", fault VA = 0x%lx", frame
->tf_addr
);
794 if (ISPL(frame
->tf_cs
) == SEL_UPL
)
795 KASSERT(td
->td_mpcount
== have_mplock
, ("badmpcount trap/end from %p", (void *)frame
->tf_rip
));
797 userret(lp
, frame
, sticks
);
804 if (p
!= NULL
&& lp
!= NULL
)
805 KTR_LOG(kernentry_trap_ret
, p
->p_pid
, lp
->lwp_tid
);
807 KASSERT(crit_count
== (td
->td_pri
& ~TDPRI_MASK
),
808 ("syscall: critical section count mismatch! %d/%d",
809 crit_count
/ TDPRI_CRIT
, td
->td_pri
/ TDPRI_CRIT
));
814 trap_pfault(struct trapframe
*frame
, int usermode
)
817 struct vmspace
*vm
= NULL
;
822 thread_t td
= curthread
;
823 struct lwp
*lp
= td
->td_lwp
;
825 va
= trunc_page(frame
->tf_addr
);
826 if (va
>= VM_MIN_KERNEL_ADDRESS
) {
828 * Don't allow user-mode faults in kernel address space.
836 * This is a fault on non-kernel virtual memory.
837 * vm is initialized above to NULL. If curproc is NULL
838 * or curproc->p_vmspace is NULL the fault is fatal.
841 vm
= lp
->lwp_vmspace
;
850 * PGEX_I is defined only if the execute disable bit capability is
851 * supported and enabled.
853 if (frame
->tf_err
& PGEX_W
)
854 ftype
= VM_PROT_WRITE
;
856 else if ((frame
->tf_err
& PGEX_I
) && pg_nx
!= 0)
857 ftype
= VM_PROT_EXECUTE
;
860 ftype
= VM_PROT_READ
;
862 if (map
!= &kernel_map
) {
864 * Keep swapout from messing with us during this
870 * Grow the stack if necessary
872 /* grow_stack returns false only if va falls into
873 * a growable stack region and the stack growth
874 * fails. It returns true if va was not within
875 * a growable stack region, or if the stack
878 if (!grow_stack(lp
->lwp_proc
, va
)) {
889 fault_flags
|= VM_FAULT_BURST
;
890 if (ftype
& VM_PROT_WRITE
)
891 fault_flags
|= VM_FAULT_DIRTY
;
893 fault_flags
|= VM_FAULT_NORMAL
;
894 rv
= vm_fault(map
, va
, ftype
, fault_flags
);
899 * Don't have to worry about process locking or stacks
902 rv
= vm_fault(map
, va
, ftype
, VM_FAULT_NORMAL
);
905 if (rv
== KERN_SUCCESS
)
909 if (td
->td_gd
->gd_intr_nesting_level
== 0 &&
910 td
->td_pcb
->pcb_onfault
) {
911 frame
->tf_rip
= (register_t
)td
->td_pcb
->pcb_onfault
;
914 trap_fatal(frame
, frame
->tf_addr
);
919 * NOTE: on x86_64 we have a tf_addr field in the trapframe, no
920 * kludge is needed to pass the fault address to signal handlers.
922 struct proc
*p
= td
->td_proc
;
923 kprintf("seg-fault accessing address %p rip=%p pid=%d p_comm=%s\n",
924 (void *)va
, (void *)frame
->tf_rip
, p
->p_pid
, p
->p_comm
);
925 /* Debugger("seg-fault"); */
927 return((rv
== KERN_PROTECTION_FAILURE
) ? SIGBUS
: SIGSEGV
);
931 trap_fatal(struct trapframe
*frame
, vm_offset_t eva
)
936 struct soft_segment_descriptor softseg
;
939 code
= frame
->tf_err
;
940 type
= frame
->tf_trapno
;
941 sdtossd(&gdt
[IDXSEL(frame
->tf_cs
& 0xffff)], &softseg
);
943 if (type
<= MAX_TRAP_MSG
)
944 msg
= trap_msg
[type
];
947 kprintf("\n\nFatal trap %d: %s while in %s mode\n", type
, msg
,
948 ISPL(frame
->tf_cs
) == SEL_UPL
? "user" : "kernel");
950 /* three separate prints in case of a trap on an unmapped page */
951 kprintf("mp_lock = %08x; ", mp_lock
);
952 kprintf("cpuid = %d; ", mycpu
->gd_cpuid
);
953 kprintf("lapic->id = %08x\n", lapic
->id
);
955 if (type
== T_PAGEFLT
) {
956 kprintf("fault virtual address = 0x%lx\n", eva
);
957 kprintf("fault code = %s %s %s, %s\n",
958 code
& PGEX_U
? "user" : "supervisor",
959 code
& PGEX_W
? "write" : "read",
960 code
& PGEX_I
? "instruction" : "data",
961 code
& PGEX_P
? "protection violation" : "page not present");
963 kprintf("instruction pointer = 0x%lx:0x%lx\n",
964 frame
->tf_cs
& 0xffff, frame
->tf_rip
);
965 if (ISPL(frame
->tf_cs
) == SEL_UPL
) {
966 ss
= frame
->tf_ss
& 0xffff;
969 ss
= GSEL(GDATA_SEL
, SEL_KPL
);
970 rsp
= (long)&frame
->tf_rsp
;
972 kprintf("stack pointer = 0x%x:0x%lx\n", ss
, rsp
);
973 kprintf("frame pointer = 0x%x:0x%lx\n", ss
, frame
->tf_rbp
);
974 kprintf("code segment = base 0x%lx, limit 0x%lx, type 0x%x\n",
975 softseg
.ssd_base
, softseg
.ssd_limit
, softseg
.ssd_type
);
976 kprintf(" = DPL %d, pres %d, long %d, def32 %d, gran %d\n",
977 softseg
.ssd_dpl
, softseg
.ssd_p
, softseg
.ssd_long
, softseg
.ssd_def32
,
979 kprintf("processor eflags = ");
980 if (frame
->tf_rflags
& PSL_T
)
981 kprintf("trace trap, ");
982 if (frame
->tf_rflags
& PSL_I
)
983 kprintf("interrupt enabled, ");
984 if (frame
->tf_rflags
& PSL_NT
)
985 kprintf("nested task, ");
986 if (frame
->tf_rflags
& PSL_RF
)
988 kprintf("IOPL = %ld\n", (frame
->tf_rflags
& PSL_IOPL
) >> 12);
989 kprintf("current process = ");
992 (u_long
)curproc
->p_pid
);
996 kprintf("current thread = pri %d ", curthread
->td_pri
);
997 if (curthread
->td_pri
>= TDPRI_CRIT
)
1002 if ((debugger_on_panic
|| db_active
) && kdb_trap(type
, code
, frame
))
1005 kprintf("trap number = %d\n", type
);
1006 if (type
<= MAX_TRAP_MSG
)
1007 panic("%s", trap_msg
[type
]);
1009 panic("unknown/reserved trap");
1013 * Double fault handler. Called when a fault occurs while writing
1014 * a frame for a trap/exception onto the stack. This usually occurs
1015 * when the stack overflows (such is the case with infinite recursion,
1019 dblfault_handler(struct trapframe
*frame
)
1021 kprintf0("DOUBLE FAULT\n");
1022 kprintf("\nFatal double fault\n");
1023 kprintf("rip = 0x%lx\n", frame
->tf_rip
);
1024 kprintf("rsp = 0x%lx\n", frame
->tf_rsp
);
1025 kprintf("rbp = 0x%lx\n", frame
->tf_rbp
);
1027 /* three separate prints in case of a trap on an unmapped page */
1028 kprintf("mp_lock = %08x; ", mp_lock
);
1029 kprintf("cpuid = %d; ", mycpu
->gd_cpuid
);
1030 kprintf("lapic->id = %08x\n", lapic
->id
);
1032 panic("double fault");
1036 * syscall2 - MP aware system call request C handler
1038 * A system call is essentially treated as a trap except that the
1039 * MP lock is not held on entry or return. We are responsible for
1040 * obtaining the MP lock if necessary and for handling ASTs
1041 * (e.g. a task switch) prior to return.
1046 syscall2(struct trapframe
*frame
)
1048 struct thread
*td
= curthread
;
1049 struct proc
*p
= td
->td_proc
;
1050 struct lwp
*lp
= td
->td_lwp
;
1052 struct sysent
*callp
;
1053 register_t orig_tf_rflags
;
1058 int crit_count
= td
->td_pri
& ~TDPRI_MASK
;
1061 int have_mplock
= 0;
1066 union sysunion args
;
1067 register_t
*argsdst
;
1069 mycpu
->gd_cnt
.v_syscall
++;
1072 if (ISPL(frame
->tf_cs
) != SEL_UPL
) {
1079 KTR_LOG(kernentry_syscall
, p
->p_pid
, lp
->lwp_tid
,
1083 KASSERT(td
->td_mpcount
== 0, ("badmpcount syscall2 from %p", (void *)frame
->tf_rip
));
1084 if (syscall_mpsafe
== 0)
1085 MAKEMPSAFE(have_mplock
);
1087 userenter(td
, p
); /* lazy raise our priority */
1094 sticks
= (int)td
->td_sticks
;
1095 orig_tf_rflags
= frame
->tf_rflags
;
1098 * Virtual kernel intercept - if a VM context managed by a virtual
1099 * kernel issues a system call the virtual kernel handles it, not us.
1100 * Restore the virtual kernel context and return from its system
1101 * call. The current frame is copied out to the virtual kernel.
1103 if (lp
->lwp_vkernel
&& lp
->lwp_vkernel
->ve
) {
1104 error
= vkernel_trap(lp
, frame
);
1105 frame
->tf_rax
= error
;
1107 frame
->tf_rflags
|= PSL_C
;
1108 error
= EJUSTRETURN
;
1113 * Get the system call parameters and account for time
1115 lp
->lwp_md
.md_regs
= frame
;
1116 params
= (caddr_t
)frame
->tf_rsp
+ sizeof(register_t
);
1117 code
= frame
->tf_rax
;
1119 if (p
->p_sysent
->sv_prepsyscall
) {
1120 (*p
->p_sysent
->sv_prepsyscall
)(
1121 frame
, (int *)(&args
.nosys
.sysmsg
+ 1),
1124 if (code
== SYS_syscall
|| code
== SYS___syscall
) {
1125 code
= frame
->tf_rdi
;
1131 if (p
->p_sysent
->sv_mask
)
1132 code
&= p
->p_sysent
->sv_mask
;
1134 if (code
>= p
->p_sysent
->sv_size
)
1135 callp
= &p
->p_sysent
->sv_table
[0];
1137 callp
= &p
->p_sysent
->sv_table
[code
];
1139 narg
= callp
->sy_narg
& SYF_ARGMASK
;
1142 * On x86_64 we get up to six arguments in registers. The rest are
1143 * on the stack. The first six members of 'struct trapframe' happen
1144 * to be the registers used to pass arguments, in exactly the right
1147 argp
= &frame
->tf_rdi
;
1149 argsdst
= (register_t
*)(&args
.nosys
.sysmsg
+ 1);
1151 * JG can we overflow the space pointed to by 'argsdst'
1152 * either with 'bcopy' or with 'copyin'?
1154 bcopy(argp
, argsdst
, sizeof(register_t
) * regcnt
);
1156 * copyin is MP aware, but the tracing code is not
1158 if (narg
> regcnt
) {
1159 KASSERT(params
!= NULL
, ("copyin args with no params!"));
1160 error
= copyin(params
, &argsdst
[regcnt
],
1161 (narg
- regcnt
) * sizeof(register_t
));
1164 if (KTRPOINT(td
, KTR_SYSCALL
)) {
1165 MAKEMPSAFE(have_mplock
);
1167 ktrsyscall(lp
, code
, narg
,
1168 (void *)(&args
.nosys
.sysmsg
+ 1));
1176 if (KTRPOINT(td
, KTR_SYSCALL
)) {
1177 MAKEMPSAFE(have_mplock
);
1178 ktrsyscall(lp
, code
, narg
, (void *)(&args
.nosys
.sysmsg
+ 1));
1183 * Default return value is 0 (will be copied to %rax). Double-value
1184 * returns use %rax and %rdx. %rdx is left unchanged for system
1185 * calls which return only one result.
1187 args
.sysmsg_fds
[0] = 0;
1188 args
.sysmsg_fds
[1] = frame
->tf_rdx
;
1191 * The syscall might manipulate the trap frame. If it does it
1192 * will probably return EJUSTRETURN.
1194 args
.sysmsg_frame
= frame
;
1196 STOPEVENT(p
, S_SCE
, narg
); /* MP aware */
1199 * NOTE: All system calls run MPSAFE now. The system call itself
1200 * is responsible for getting the MP lock.
1202 error
= (*callp
->sy_call
)(&args
);
1206 * MP SAFE (we may or may not have the MP lock at this point)
1208 //kprintf("SYSMSG %d ", error);
1212 * Reinitialize proc pointer `p' as it may be different
1213 * if this is a child returning from fork syscall.
1216 lp
= curthread
->td_lwp
;
1217 frame
->tf_rax
= args
.sysmsg_fds
[0];
1218 frame
->tf_rdx
= args
.sysmsg_fds
[1];
1219 frame
->tf_rflags
&= ~PSL_C
;
1223 * Reconstruct pc, we know that 'syscall' is 2 bytes.
1224 * We have to do a full context restore so that %r10
1225 * (which was holding the value of %rcx) is restored for
1226 * the next iteration.
1228 frame
->tf_rip
-= frame
->tf_err
;
1229 frame
->tf_r10
= frame
->tf_rcx
;
1234 panic("Unexpected EASYNC return value (for now)");
1237 if (p
->p_sysent
->sv_errsize
) {
1238 if (error
>= p
->p_sysent
->sv_errsize
)
1239 error
= -1; /* XXX */
1241 error
= p
->p_sysent
->sv_errtbl
[error
];
1243 frame
->tf_rax
= error
;
1244 frame
->tf_rflags
|= PSL_C
;
1249 * Traced syscall. trapsignal() is not MP aware.
1251 if (orig_tf_rflags
& PSL_T
) {
1252 MAKEMPSAFE(have_mplock
);
1253 frame
->tf_rflags
&= ~PSL_T
;
1254 trapsignal(lp
, SIGTRAP
, TRAP_TRACE
);
1258 * Handle reschedule and other end-of-syscall issues
1260 userret(lp
, frame
, sticks
);
1263 if (KTRPOINT(td
, KTR_SYSRET
)) {
1264 MAKEMPSAFE(have_mplock
);
1265 ktrsysret(lp
, code
, error
, args
.sysmsg_result
);
1270 * This works because errno is findable through the
1271 * register set. If we ever support an emulation where this
1272 * is not the case, this code will need to be revisited.
1274 STOPEVENT(p
, S_SCX
, code
);
1279 * Release the MP lock if we had to get it
1281 KASSERT(td
->td_mpcount
== have_mplock
,
1282 ("badmpcount syscall2/end from %p", (void *)frame
->tf_rip
));
1286 KTR_LOG(kernentry_syscall_ret
, p
->p_pid
, lp
->lwp_tid
, error
);
1288 KASSERT(crit_count
== (td
->td_pri
& ~TDPRI_MASK
),
1289 ("syscall: critical section count mismatch! %d/%d",
1290 crit_count
/ TDPRI_CRIT
, td
->td_pri
/ TDPRI_CRIT
));
1295 fork_return(struct lwp
*lp
, struct trapframe
*frame
)
1297 frame
->tf_rax
= 0; /* Child returns zero */
1298 frame
->tf_rflags
&= ~PSL_C
; /* success */
1301 generic_lwp_return(lp
, frame
);
1302 KTR_LOG(kernentry_fork_ret
, lp
->lwp_proc
->p_pid
, lp
->lwp_tid
);
1306 * Simplified back end of syscall(), used when returning from fork()
1307 * directly into user mode. MP lock is held on entry and should be
1308 * released on return. This code will return back into the fork
1309 * trampoline code which then runs doreti.
1312 generic_lwp_return(struct lwp
*lp
, struct trapframe
*frame
)
1314 struct proc
*p
= lp
->lwp_proc
;
1317 * Newly forked processes are given a kernel priority. We have to
1318 * adjust the priority to a normal user priority and fake entry
1319 * into the kernel (call userenter()) to install a passive release
1320 * function just in case userret() decides to stop the process. This
1321 * can occur when ^Z races a fork. If we do not install the passive
1322 * release function the current process designation will not be
1323 * released when the thread goes to sleep.
1325 lwkt_setpri_self(TDPRI_USER_NORM
);
1326 userenter(lp
->lwp_thread
, p
);
1327 userret(lp
, frame
, 0);
1329 if (KTRPOINT(lp
->lwp_thread
, KTR_SYSRET
))
1330 ktrsysret(lp
, SYS_fork
, 0, 0);
1332 p
->p_flag
|= P_PASSIVE_ACQ
;
1334 p
->p_flag
&= ~P_PASSIVE_ACQ
;
1336 KKASSERT(lp
->lwp_thread
->td_mpcount
== 1);
1342 * If PGEX_FPFAULT is set then set FP_VIRTFP in the PCB to force a T_DNA
1343 * fault (which is then passed back to the virtual kernel) if an attempt is
1344 * made to use the FP unit.
1346 * XXX this is a fairly big hack.
1349 set_vkernel_fp(struct trapframe
*frame
)