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 $
42 * x86_64 Trap and System call handling
48 #include "opt_ktrace.h"
50 #include <sys/param.h>
51 #include <sys/systm.h>
53 #include <sys/pioctl.h>
54 #include <sys/kernel.h>
55 #include <sys/resourcevar.h>
56 #include <sys/signalvar.h>
57 #include <sys/signal2.h>
58 #include <sys/syscall.h>
59 #include <sys/sysctl.h>
60 #include <sys/sysent.h>
62 #include <sys/vmmeter.h>
63 #include <sys/malloc.h>
65 #include <sys/ktrace.h>
68 #include <sys/vkernel.h>
69 #include <sys/sysproto.h>
70 #include <sys/sysunion.h>
71 #include <sys/vmspace.h>
74 #include <vm/vm_param.h>
77 #include <vm/vm_kern.h>
78 #include <vm/vm_map.h>
79 #include <vm/vm_page.h>
80 #include <vm/vm_extern.h>
82 #include <machine/cpu.h>
83 #include <machine/md_var.h>
84 #include <machine/pcb.h>
85 #include <machine/smp.h>
86 #include <machine/tss.h>
87 #include <machine/globaldata.h>
91 #include <sys/msgport2.h>
92 #include <sys/thread2.h>
93 #include <sys/mplock2.h>
95 int (*pmath_emulate
) (struct trapframe
*);
97 static int trap_pfault (struct trapframe
*, int, vm_offset_t
);
98 static void trap_fatal (struct trapframe
*, int, vm_offset_t
);
99 void dblfault_handler (void);
100 extern int vmm_enabled
;
103 extern inthand_t
IDTVEC(syscall
);
106 #define MAX_TRAP_MSG 30
107 static char *trap_msg
[] = {
109 "privileged instruction fault", /* 1 T_PRIVINFLT */
111 "breakpoint instruction fault", /* 3 T_BPTFLT */
114 "arithmetic trap", /* 6 T_ARITHTRAP */
115 "system forced exception", /* 7 T_ASTFLT */
117 "general protection fault", /* 9 T_PROTFLT */
118 "trace trap", /* 10 T_TRCTRAP */
120 "page fault", /* 12 T_PAGEFLT */
122 "alignment fault", /* 14 T_ALIGNFLT */
126 "integer divide fault", /* 18 T_DIVIDE */
127 "non-maskable interrupt trap", /* 19 T_NMI */
128 "overflow trap", /* 20 T_OFLOW */
129 "FPU bounds check fault", /* 21 T_BOUND */
130 "FPU device not available", /* 22 T_DNA */
131 "double fault", /* 23 T_DOUBLEFLT */
132 "FPU operand fetch fault", /* 24 T_FPOPFLT */
133 "invalid TSS fault", /* 25 T_TSSFLT */
134 "segment not present fault", /* 26 T_SEGNPFLT */
135 "stack fault", /* 27 T_STKFLT */
136 "machine check trap", /* 28 T_MCHK */
137 "SIMD floating-point exception", /* 29 T_XMMFLT */
138 "reserved (unknown) fault", /* 30 T_RESERVED */
142 static int ddb_on_nmi
= 1;
143 SYSCTL_INT(_machdep
, OID_AUTO
, ddb_on_nmi
, CTLFLAG_RW
,
144 &ddb_on_nmi
, 0, "Go to DDB on NMI");
146 static int panic_on_nmi
= 1;
147 SYSCTL_INT(_machdep
, OID_AUTO
, panic_on_nmi
, CTLFLAG_RW
,
148 &panic_on_nmi
, 0, "Panic on NMI");
149 static int fast_release
;
150 SYSCTL_INT(_machdep
, OID_AUTO
, fast_release
, CTLFLAG_RW
,
151 &fast_release
, 0, "Passive Release was optimal");
152 static int slow_release
;
153 SYSCTL_INT(_machdep
, OID_AUTO
, slow_release
, CTLFLAG_RW
,
154 &slow_release
, 0, "Passive Release was nonoptimal");
157 * Passively intercepts the thread switch function to increase
158 * the thread priority from a user priority to a kernel priority, reducing
159 * syscall and trap overhead for the case where no switch occurs.
161 * Synchronizes td_ucred with p_ucred. This is used by system calls,
162 * signal handling, faults, AST traps, and anything else that enters the
163 * kernel from userland and provides the kernel with a stable read-only
164 * copy of the process ucred.
167 userenter(struct thread
*curtd
, struct proc
*curp
)
172 curtd
->td_release
= lwkt_passive_release
;
174 if (curtd
->td_ucred
!= curp
->p_ucred
) {
175 ncred
= crhold(curp
->p_ucred
);
176 ocred
= curtd
->td_ucred
;
177 curtd
->td_ucred
= ncred
;
184 * Handle signals, profiling, and other AST's and/or tasks that
185 * must be completed before we can return to or try to return to userland.
187 * Note that td_sticks is a 64 bit quantity, but there's no point doing 64
188 * arithmatic on the delta calculation so the absolute tick values are
189 * truncated to an integer.
192 userret(struct lwp
*lp
, struct trapframe
*frame
, int sticks
)
194 struct proc
*p
= lp
->lwp_proc
;
199 * Charge system time if profiling. Note: times are in microseconds.
200 * This may do a copyout and block, so do it first even though it
201 * means some system time will be charged as user time.
203 if (p
->p_flags
& P_PROFIL
) {
204 addupc_task(p
, frame
->tf_rip
,
205 (u_int
)((int)lp
->lwp_thread
->td_sticks
- sticks
));
210 * Specific on-return-to-usermode checks (LWP_MP_WEXIT,
211 * LWP_MP_VNLRU, etc).
213 if (lp
->lwp_mpflags
& LWP_MP_URETMASK
)
217 * Block here if we are in a stopped state.
219 if (STOPLWP(p
, lp
)) {
220 lwkt_gettoken(&p
->p_token
);
222 lwkt_reltoken(&p
->p_token
);
227 * Post any pending upcalls. If running a virtual kernel be sure
228 * to restore the virtual kernel's vmspace before posting the upcall.
230 if (p
->p_flags
& (P_SIGVTALRM
| P_SIGPROF
)) {
231 lwkt_gettoken(&p
->p_token
);
232 if (p
->p_flags
& P_SIGVTALRM
) {
233 p
->p_flags
&= ~P_SIGVTALRM
;
234 ksignal(p
, SIGVTALRM
);
236 if (p
->p_flags
& P_SIGPROF
) {
237 p
->p_flags
&= ~P_SIGPROF
;
240 lwkt_reltoken(&p
->p_token
);
245 * Post any pending signals
247 * WARNING! postsig() can exit and not return.
249 if ((sig
= CURSIG_LCK_TRACE(lp
, &ptok
)) != 0) {
255 * block here if we are swapped out, but still process signals
256 * (such as SIGKILL). proc0 (the swapin scheduler) is already
257 * aware of our situation, we do not have to wake it up.
259 if (p
->p_flags
& P_SWAPPEDOUT
) {
260 lwkt_gettoken(&p
->p_token
);
262 p
->p_flags
|= P_SWAPWAIT
;
264 if (p
->p_flags
& P_SWAPWAIT
)
265 tsleep(p
, PCATCH
, "SWOUT", 0);
266 p
->p_flags
&= ~P_SWAPWAIT
;
268 lwkt_reltoken(&p
->p_token
);
273 * In a multi-threaded program it is possible for a thread to change
274 * signal state during a system call which temporarily changes the
275 * signal mask. In this case postsig() might not be run and we
276 * have to restore the mask ourselves.
278 if (lp
->lwp_flags
& LWP_OLDMASK
) {
279 lp
->lwp_flags
&= ~LWP_OLDMASK
;
280 lp
->lwp_sigmask
= lp
->lwp_oldsigmask
;
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 (STOPLWP(lp
->lwp_proc
, lp
)) {
301 lwkt_gettoken(&lp
->lwp_proc
->p_token
);
303 lwkt_reltoken(&lp
->lwp_proc
->p_token
);
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,
327 "TRAP(pid %hd, tid %hd, trapno %ld, eva %lu)",
328 pid_t pid
, lwpid_t tid
, register_t trapno
, vm_offset_t eva
);
329 KTR_INFO(KTR_KERNENTRY
, kernentry
, trap_ret
, 0, "TRAP_RET(pid %hd, tid %hd)",
330 pid_t pid
, lwpid_t tid
);
331 KTR_INFO(KTR_KERNENTRY
, kernentry
, syscall
, 0, "SYSC(pid %hd, tid %hd, nr %ld)",
332 pid_t pid
, lwpid_t tid
, register_t trapno
);
333 KTR_INFO(KTR_KERNENTRY
, kernentry
, syscall_ret
, 0, "SYSRET(pid %hd, tid %hd, err %d)",
334 pid_t pid
, lwpid_t tid
, int err
);
335 KTR_INFO(KTR_KERNENTRY
, kernentry
, fork_ret
, 0, "FORKRET(pid %hd, tid %hd)",
336 pid_t pid
, lwpid_t tid
);
339 * Exception, fault, and trap interface to the kernel.
340 * This common code is called from assembly language IDT gate entry
341 * routines that prepare a suitable stack frame, and restore this
342 * frame after the exception has been processed.
344 * This function is also called from doreti in an interlock to handle ASTs.
345 * For example: hardwareint->INTROUTINE->(set ast)->doreti->trap
347 * NOTE! We have to retrieve the fault address prior to obtaining the
348 * MP lock because get_mplock() may switch out. YYY cr2 really ought
349 * to be retrieved by the assembly code, not here.
351 * XXX gd_trap_nesting_level currently prevents lwkt_switch() from panicing
352 * if an attempt is made to switch from a fast interrupt or IPI. This is
353 * necessary to properly take fatal kernel traps on SMP machines if
354 * get_mplock() has to block.
358 user_trap(struct trapframe
*frame
)
360 struct globaldata
*gd
= mycpu
;
361 struct thread
*td
= gd
->gd_curthread
;
362 struct lwp
*lp
= td
->td_lwp
;
365 int i
= 0, ucode
= 0, type
, code
;
367 int crit_count
= td
->td_critcount
;
368 lwkt_tokref_t curstop
= td
->td_toks_stop
;
374 if (frame
->tf_trapno
== T_PAGEFLT
)
375 eva
= frame
->tf_addr
;
379 kprintf("USER_TRAP AT %08lx xflags %ld trapno %ld eva %08lx\n",
380 frame
->tf_rip
, frame
->tf_xflags
, frame
->tf_trapno
, eva
);
384 * Everything coming from user mode runs through user_trap,
385 * including system calls.
387 if (frame
->tf_trapno
== T_FAST_SYSCALL
) {
392 KTR_LOG(kernentry_trap
, lp
->lwp_proc
->p_pid
, lp
->lwp_tid
,
393 frame
->tf_trapno
, eva
);
397 eva
= (frame
->tf_trapno
== T_PAGEFLT
? rcr2() : 0);
398 ++gd
->gd_trap_nesting_level
;
399 trap_fatal(frame
, TRUE
, eva
);
400 --gd
->gd_trap_nesting_level
;
405 type
= frame
->tf_trapno
;
406 code
= frame
->tf_err
;
410 sticks
= (int)td
->td_sticks
;
411 lp
->lwp_md
.md_regs
= frame
;
414 case T_PRIVINFLT
: /* privileged instruction fault */
419 case T_BPTFLT
: /* bpt instruction fault */
420 case T_TRCTRAP
: /* trace trap */
421 frame
->tf_rflags
&= ~PSL_T
;
423 ucode
= (type
== T_TRCTRAP
? TRAP_TRACE
: TRAP_BRKPT
);
426 case T_ARITHTRAP
: /* arithmetic trap */
431 case T_ASTFLT
: /* Allow process switch */
432 mycpu
->gd_cnt
.v_soft
++;
433 if (mycpu
->gd_reqflags
& RQF_AST_OWEUPC
) {
434 atomic_clear_int(&mycpu
->gd_reqflags
, RQF_AST_OWEUPC
);
435 addupc_task(p
, p
->p_prof
.pr_addr
, p
->p_prof
.pr_ticks
);
440 * The following two traps can happen in
441 * vm86 mode, and, if so, we want to handle
444 case T_PROTFLT
: /* general protection fault */
445 case T_STKFLT
: /* stack fault */
447 if (frame
->tf_eflags
& PSL_VM
) {
448 i
= vm86_emulate((struct vm86frame
*)frame
);
456 case T_SEGNPFLT
: /* segment not present fault */
457 case T_TSSFLT
: /* invalid TSS fault */
458 case T_DOUBLEFLT
: /* double fault */
461 ucode
= code
+ BUS_SEGM_FAULT
;
464 case T_PAGEFLT
: /* page fault */
465 i
= trap_pfault(frame
, TRUE
, eva
);
466 if (i
== -1 || i
== 0)
478 case T_DIVIDE
: /* integer divide fault */
485 /* machine/parity/power fail/"kitchen sink" faults */
486 if (isa_nmi(code
) == 0) {
489 * NMI can be hooked up to a pushbutton
493 kprintf ("NMI ... going to debugger\n");
494 kdb_trap(type
, 0, frame
);
498 } else if (panic_on_nmi
)
499 panic("NMI indicates hardware failure");
501 #endif /* NISA > 0 */
503 case T_OFLOW
: /* integer overflow fault */
508 case T_BOUND
: /* bounds check fault */
515 * Virtual kernel intercept - pass the DNA exception
516 * to the (emulated) virtual kernel if it asked to handle
517 * it. This occurs when the virtual kernel is holding
518 * onto the FP context for a different emulated
519 * process then the one currently running.
521 * We must still call npxdna() since we may have
522 * saved FP state that the (emulated) virtual kernel
523 * needs to hand over to a different emulated process.
525 if (lp
->lwp_vkernel
&& lp
->lwp_vkernel
->ve
&&
526 (td
->td_pcb
->pcb_flags
& FP_VIRTFP
)
533 * The kernel may have switched out the FP unit's
534 * state, causing the user process to take a fault
535 * when it tries to use the FP unit. Restore the
540 if (!pmath_emulate
) {
542 ucode
= FPE_FPU_NP_TRAP
;
545 i
= (*pmath_emulate
)(frame
);
547 if (!(frame
->tf_rflags
& PSL_T
))
549 frame
->tf_rflags
&= ~PSL_T
;
552 /* else ucode = emulator_only_knows() XXX */
555 case T_FPOPFLT
: /* FPU operand fetch fault */
560 case T_XMMFLT
: /* SIMD floating-point exception */
567 * Virtual kernel intercept - if the fault is directly related to a
568 * VM context managed by a virtual kernel then let the virtual kernel
571 if (lp
->lwp_vkernel
&& lp
->lwp_vkernel
->ve
) {
572 vkernel_trap(lp
, frame
);
577 * Translate fault for emulators (e.g. Linux)
579 if (*p
->p_sysent
->sv_transtrap
)
580 i
= (*p
->p_sysent
->sv_transtrap
)(i
, type
);
582 trapsignal(lp
, i
, ucode
);
585 if (type
<= MAX_TRAP_MSG
) {
586 uprintf("fatal process exception: %s",
588 if ((type
== T_PAGEFLT
) || (type
== T_PROTFLT
))
589 uprintf(", fault VA = 0x%lx", (u_long
)eva
);
595 userret(lp
, frame
, sticks
);
598 KTR_LOG(kernentry_trap_ret
, lp
->lwp_proc
->p_pid
, lp
->lwp_tid
);
600 KASSERT(crit_count
== td
->td_critcount
,
601 ("trap: critical section count mismatch! %d/%d",
602 crit_count
, td
->td_pri
));
603 KASSERT(curstop
== td
->td_toks_stop
,
604 ("trap: extra tokens held after trap! %ld/%ld",
605 curstop
- &td
->td_toks_base
,
606 td
->td_toks_stop
- &td
->td_toks_base
));
611 kern_trap(struct trapframe
*frame
)
613 struct globaldata
*gd
= mycpu
;
614 struct thread
*td
= gd
->gd_curthread
;
617 int i
= 0, ucode
= 0, type
, code
;
619 int crit_count
= td
->td_critcount
;
620 lwkt_tokref_t curstop
= td
->td_toks_stop
;
627 if (frame
->tf_trapno
== T_PAGEFLT
)
628 eva
= frame
->tf_addr
;
634 ++gd
->gd_trap_nesting_level
;
635 trap_fatal(frame
, FALSE
, eva
);
636 --gd
->gd_trap_nesting_level
;
641 type
= frame
->tf_trapno
;
642 code
= frame
->tf_err
;
650 case T_PAGEFLT
: /* page fault */
651 trap_pfault(frame
, FALSE
, eva
);
656 * The kernel may be using npx for copying or other
659 panic("kernel NPX should not happen");
664 case T_PROTFLT
: /* general protection fault */
665 case T_SEGNPFLT
: /* segment not present fault */
667 * Invalid segment selectors and out of bounds
668 * %eip's and %esp's can be set up in user mode.
669 * This causes a fault in kernel mode when the
670 * kernel tries to return to user mode. We want
671 * to get this fault so that we can fix the
672 * problem here and not have to check all the
673 * selectors and pointers when the user changes
676 if (mycpu
->gd_intr_nesting_level
== 0) {
677 if (td
->td_pcb
->pcb_onfault
) {
679 (register_t
)td
->td_pcb
->pcb_onfault
;
687 * PSL_NT can be set in user mode and isn't cleared
688 * automatically when the kernel is entered. This
689 * causes a TSS fault when the kernel attempts to
690 * `iret' because the TSS link is uninitialized. We
691 * want to get this fault so that we can fix the
692 * problem here and not every time the kernel is
695 if (frame
->tf_rflags
& PSL_NT
) {
696 frame
->tf_rflags
&= ~PSL_NT
;
701 case T_TRCTRAP
: /* trace trap */
703 if (frame
->tf_eip
== (int)IDTVEC(syscall
)) {
705 * We've just entered system mode via the
706 * syscall lcall. Continue single stepping
707 * silently until the syscall handler has
712 if (frame
->tf_eip
== (int)IDTVEC(syscall
) + 1) {
714 * The syscall handler has now saved the
715 * flags. Stop single stepping it.
717 frame
->tf_eflags
&= ~PSL_T
;
723 * Ignore debug register trace traps due to
724 * accesses in the user's address space, which
725 * can happen under several conditions such as
726 * if a user sets a watchpoint on a buffer and
727 * then passes that buffer to a system call.
728 * We still want to get TRCTRAPS for addresses
729 * in kernel space because that is useful when
730 * debugging the kernel.
732 if (user_dbreg_trap()) {
734 * Reset breakpoint bits because the
737 load_dr6(rdr6() & 0xfffffff0);
742 * Fall through (TRCTRAP kernel mode, kernel address)
746 * If DDB is enabled, let it handle the debugger trap.
747 * Otherwise, debugger traps "can't happen".
750 if (kdb_trap (type
, 0, frame
))
755 trap_fatal(frame
, FALSE
, eva
);
758 trap_fatal(frame
, FALSE
, eva
);
763 * Ignore this trap generated from a spurious SIGTRAP.
765 * single stepping in / syscalls leads to spurious / SIGTRAP
768 * Haiku (c) 2007 Simon 'corecode' Schubert
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 trapsignal(lp
, i
, ucode
);
782 if (type
<= MAX_TRAP_MSG
) {
783 uprintf("fatal process exception: %s",
785 if ((type
== T_PAGEFLT
) || (type
== T_PROTFLT
))
786 uprintf(", fault VA = 0x%lx", (u_long
)eva
);
794 KASSERT(crit_count
== td
->td_critcount
,
795 ("trap: critical section count mismatch! %d/%d",
796 crit_count
, td
->td_pri
));
797 KASSERT(curstop
== td
->td_toks_stop
,
798 ("trap: extra tokens held after trap! %ld/%ld",
799 curstop
- &td
->td_toks_base
,
800 td
->td_toks_stop
- &td
->td_toks_base
));
805 trap_pfault(struct trapframe
*frame
, int usermode
, vm_offset_t eva
)
808 struct vmspace
*vm
= NULL
;
812 thread_t td
= curthread
;
813 struct lwp
*lp
= td
->td_lwp
;
816 va
= trunc_page(eva
);
817 if (usermode
== FALSE
) {
819 * This is a fault on kernel virtual memory.
824 * This is a fault on non-kernel virtual memory.
825 * vm is initialized above to NULL. If curproc is NULL
826 * or curproc->p_vmspace is NULL the fault is fatal.
829 vm
= lp
->lwp_vmspace
;
837 if (frame
->tf_err
& PGEX_W
)
838 ftype
= VM_PROT_READ
| VM_PROT_WRITE
;
840 ftype
= VM_PROT_READ
;
842 if (map
!= &kernel_map
) {
844 * Keep swapout from messing with us during this
851 * Grow the stack if necessary
853 /* grow_stack returns false only if va falls into
854 * a growable stack region and the stack growth
855 * fails. It returns true if va was not within
856 * a growable stack region, or if the stack
859 if (!grow_stack (map
, va
)) {
868 fault_flags
|= VM_FAULT_BURST
| VM_FAULT_USERMODE
;
869 if (ftype
& VM_PROT_WRITE
)
870 fault_flags
|= VM_FAULT_DIRTY
;
872 fault_flags
|= VM_FAULT_NORMAL
;
873 rv
= vm_fault(map
, va
, ftype
, fault_flags
);
878 * Don't have to worry about process locking or stacks in the kernel.
880 rv
= vm_fault(map
, va
, ftype
, VM_FAULT_NORMAL
);
883 if (rv
== KERN_SUCCESS
)
887 if (td
->td_gd
->gd_intr_nesting_level
== 0 &&
888 td
->td_pcb
->pcb_onfault
) {
889 frame
->tf_rip
= (register_t
)td
->td_pcb
->pcb_onfault
;
892 trap_fatal(frame
, usermode
, eva
);
897 * NOTE: on x86_64 we have a tf_addr field in the trapframe, no
898 * kludge is needed to pass the fault address to signal handlers.
900 struct proc
*p
= td
->td_proc
;
901 kprintf("seg-fault accessing address %p rip=%p pid=%d p_comm=%s\n",
902 (void *)va
, (void *)frame
->tf_rip
, p
->p_pid
, p
->p_comm
);
903 /* Debugger("seg-fault"); */
905 return((rv
== KERN_PROTECTION_FAILURE
) ? SIGBUS
: SIGSEGV
);
909 trap_fatal(struct trapframe
*frame
, int usermode
, vm_offset_t eva
)
914 code
= frame
->tf_xflags
;
915 type
= frame
->tf_trapno
;
917 if (type
<= MAX_TRAP_MSG
) {
918 kprintf("\n\nFatal trap %d: %s while in %s mode\n",
919 type
, trap_msg
[type
],
920 (usermode
? "user" : "kernel"));
922 /* two separate prints in case of a trap on an unmapped page */
923 kprintf("cpuid = %d\n", mycpu
->gd_cpuid
);
924 if (type
== T_PAGEFLT
) {
925 kprintf("fault virtual address = %p\n", (void *)eva
);
926 kprintf("fault code = %s %s, %s\n",
927 usermode
? "user" : "supervisor",
928 code
& PGEX_W
? "write" : "read",
929 code
& PGEX_P
? "protection violation" : "page not present");
931 kprintf("instruction pointer = 0x%lx:0x%lx\n",
932 frame
->tf_cs
& 0xffff, frame
->tf_rip
);
934 ss
= frame
->tf_ss
& 0xffff;
937 ss
= GSEL(GDATA_SEL
, SEL_KPL
);
938 rsp
= (long)&frame
->tf_rsp
;
940 kprintf("stack pointer = 0x%x:0x%lx\n", ss
, rsp
);
941 kprintf("frame pointer = 0x%x:0x%lx\n", ss
, frame
->tf_rbp
);
942 kprintf("processor eflags = ");
943 if (frame
->tf_rflags
& PSL_T
)
944 kprintf("trace trap, ");
945 if (frame
->tf_rflags
& PSL_I
)
946 kprintf("interrupt enabled, ");
947 if (frame
->tf_rflags
& PSL_NT
)
948 kprintf("nested task, ");
949 if (frame
->tf_rflags
& PSL_RF
)
952 if (frame
->tf_eflags
& PSL_VM
)
955 kprintf("IOPL = %jd\n", (intmax_t)((frame
->tf_rflags
& PSL_IOPL
) >> 12));
956 kprintf("current process = ");
958 kprintf("%lu (%s)\n",
959 (u_long
)curproc
->p_pid
, curproc
->p_comm
?
960 curproc
->p_comm
: "");
964 kprintf("current thread = pri %d ", curthread
->td_pri
);
965 if (curthread
->td_critcount
)
970 * we probably SHOULD have stopped the other CPUs before now!
971 * another CPU COULD have been touching cpl at this moment...
973 kprintf(" <- SMP: XXX");
981 if ((debugger_on_panic
|| db_active
) && kdb_trap(type
, code
, frame
))
984 kprintf("trap number = %d\n", type
);
985 if (type
<= MAX_TRAP_MSG
)
986 panic("%s", trap_msg
[type
]);
988 panic("unknown/reserved trap");
992 * Double fault handler. Called when a fault occurs while writing
993 * a frame for a trap/exception onto the stack. This usually occurs
994 * when the stack overflows (such is the case with infinite recursion,
997 * XXX Note that the current PTD gets replaced by IdlePTD when the
998 * task switch occurs. This means that the stack that was active at
999 * the time of the double fault is not available at <kstack> unless
1000 * the machine was idle when the double fault occurred. The downside
1001 * of this is that "trace <ebp>" in ddb won't work.
1004 dblfault_handler(void)
1007 struct mdglobaldata
*gd
= mdcpu
;
1010 kprintf("\nFatal double fault:\n");
1012 kprintf("rip = 0x%lx\n", gd
->gd_common_tss
.tss_rip
);
1013 kprintf("rsp = 0x%lx\n", gd
->gd_common_tss
.tss_rsp
);
1014 kprintf("rbp = 0x%lx\n", gd
->gd_common_tss
.tss_rbp
);
1016 /* two separate prints in case of a trap on an unmapped page */
1017 kprintf("cpuid = %d\n", mycpu
->gd_cpuid
);
1018 panic("double fault");
1022 * syscall2 - MP aware system call request C handler
1024 * A system call is essentially treated as a trap except that the
1025 * MP lock is not held on entry or return. We are responsible for
1026 * obtaining the MP lock if necessary and for handling ASTs
1027 * (e.g. a task switch) prior to return.
1029 * In general, only simple access and manipulation of curproc and
1030 * the current stack is allowed without having to hold MP lock.
1032 * MPSAFE - note that large sections of this routine are run without
1036 syscall2(struct trapframe
*frame
)
1038 struct thread
*td
= curthread
;
1039 struct proc
*p
= td
->td_proc
;
1040 struct lwp
*lp
= td
->td_lwp
;
1042 struct sysent
*callp
;
1043 register_t orig_tf_rflags
;
1048 int crit_count
= td
->td_critcount
;
1049 lwkt_tokref_t curstop
= td
->td_toks_stop
;
1054 union sysunion args
;
1055 register_t
*argsdst
;
1057 mycpu
->gd_cnt
.v_syscall
++;
1059 KTR_LOG(kernentry_syscall
, lp
->lwp_proc
->p_pid
, lp
->lwp_tid
,
1062 userenter(td
, p
); /* lazy raise our priority */
1069 sticks
= (int)td
->td_sticks
;
1070 orig_tf_rflags
= frame
->tf_rflags
;
1073 * Virtual kernel intercept - if a VM context managed by a virtual
1074 * kernel issues a system call the virtual kernel handles it, not us.
1075 * Restore the virtual kernel context and return from its system
1076 * call. The current frame is copied out to the virtual kernel.
1078 if (lp
->lwp_vkernel
&& lp
->lwp_vkernel
->ve
) {
1079 vkernel_trap(lp
, frame
);
1080 error
= EJUSTRETURN
;
1085 * Get the system call parameters and account for time
1087 lp
->lwp_md
.md_regs
= frame
;
1088 params
= (caddr_t
)frame
->tf_rsp
+ sizeof(register_t
);
1089 code
= frame
->tf_rax
;
1091 if (p
->p_sysent
->sv_prepsyscall
) {
1092 (*p
->p_sysent
->sv_prepsyscall
)(
1093 frame
, (int *)(&args
.nosys
.sysmsg
+ 1),
1096 if (code
== SYS_syscall
|| code
== SYS___syscall
) {
1097 code
= frame
->tf_rdi
;
1103 if (p
->p_sysent
->sv_mask
)
1104 code
&= p
->p_sysent
->sv_mask
;
1106 if (code
>= p
->p_sysent
->sv_size
)
1107 callp
= &p
->p_sysent
->sv_table
[0];
1109 callp
= &p
->p_sysent
->sv_table
[code
];
1111 narg
= callp
->sy_narg
& SYF_ARGMASK
;
1114 * On x86_64 we get up to six arguments in registers. The rest are
1115 * on the stack. The first six members of 'struct trapframe' happen
1116 * to be the registers used to pass arguments, in exactly the right
1119 argp
= &frame
->tf_rdi
;
1121 argsdst
= (register_t
*)(&args
.nosys
.sysmsg
+ 1);
1123 * JG can we overflow the space pointed to by 'argsdst'
1124 * either with 'bcopy' or with 'copyin'?
1126 bcopy(argp
, argsdst
, sizeof(register_t
) * regcnt
);
1128 * copyin is MP aware, but the tracing code is not
1130 if (narg
> regcnt
) {
1131 KASSERT(params
!= NULL
, ("copyin args with no params!"));
1132 error
= copyin(params
, &argsdst
[regcnt
],
1133 (narg
- regcnt
) * sizeof(register_t
));
1136 if (KTRPOINT(td
, KTR_SYSCALL
)) {
1137 ktrsyscall(lp
, code
, narg
,
1138 (void *)(&args
.nosys
.sysmsg
+ 1));
1146 if (KTRPOINT(td
, KTR_SYSCALL
)) {
1147 ktrsyscall(lp
, code
, narg
, (void *)(&args
.nosys
.sysmsg
+ 1));
1152 * Default return value is 0 (will be copied to %rax). Double-value
1153 * returns use %rax and %rdx. %rdx is left unchanged for system
1154 * calls which return only one result.
1156 args
.sysmsg_fds
[0] = 0;
1157 args
.sysmsg_fds
[1] = frame
->tf_rdx
;
1160 * The syscall might manipulate the trap frame. If it does it
1161 * will probably return EJUSTRETURN.
1163 args
.sysmsg_frame
= frame
;
1165 STOPEVENT(p
, S_SCE
, narg
); /* MP aware */
1168 * NOTE: All system calls run MPSAFE now. The system call itself
1169 * is responsible for getting the MP lock.
1171 error
= (*callp
->sy_call
)(&args
);
1174 kprintf("system call %d returned %d\n", code
, error
);
1179 * MP SAFE (we may or may not have the MP lock at this point)
1184 * Reinitialize proc pointer `p' as it may be different
1185 * if this is a child returning from fork syscall.
1188 lp
= curthread
->td_lwp
;
1189 frame
->tf_rax
= args
.sysmsg_fds
[0];
1190 frame
->tf_rdx
= args
.sysmsg_fds
[1];
1191 frame
->tf_rflags
&= ~PSL_C
;
1195 * Reconstruct pc, we know that 'syscall' is 2 bytes.
1196 * We have to do a full context restore so that %r10
1197 * (which was holding the value of %rcx) is restored for
1198 * the next iteration.
1200 frame
->tf_rip
-= frame
->tf_err
;
1201 frame
->tf_r10
= frame
->tf_rcx
;
1206 panic("Unexpected EASYNC return value (for now)");
1209 if (p
->p_sysent
->sv_errsize
) {
1210 if (error
>= p
->p_sysent
->sv_errsize
)
1211 error
= -1; /* XXX */
1213 error
= p
->p_sysent
->sv_errtbl
[error
];
1215 frame
->tf_rax
= error
;
1216 frame
->tf_rflags
|= PSL_C
;
1221 * Traced syscall. trapsignal() is not MP aware.
1223 if (orig_tf_rflags
& PSL_T
) {
1224 frame
->tf_rflags
&= ~PSL_T
;
1225 trapsignal(lp
, SIGTRAP
, 0);
1229 * Handle reschedule and other end-of-syscall issues
1231 userret(lp
, frame
, sticks
);
1234 if (KTRPOINT(td
, KTR_SYSRET
)) {
1235 ktrsysret(lp
, code
, error
, args
.sysmsg_result
);
1240 * This works because errno is findable through the
1241 * register set. If we ever support an emulation where this
1242 * is not the case, this code will need to be revisited.
1244 STOPEVENT(p
, S_SCX
, code
);
1247 KTR_LOG(kernentry_syscall_ret
, lp
->lwp_proc
->p_pid
, lp
->lwp_tid
, error
);
1249 KASSERT(&td
->td_toks_base
== td
->td_toks_stop
,
1250 ("syscall: critical section count mismatch! %d/%d",
1251 crit_count
, td
->td_pri
));
1252 KASSERT(curstop
== td
->td_toks_stop
,
1253 ("syscall: extra tokens held after trap! %ld",
1254 td
->td_toks_stop
- &td
->td_toks_base
));
1259 * NOTE: mplock not held at any point
1262 fork_return(struct lwp
*lp
, struct trapframe
*frame
)
1264 frame
->tf_rax
= 0; /* Child returns zero */
1265 frame
->tf_rflags
&= ~PSL_C
; /* success */
1268 generic_lwp_return(lp
, frame
);
1269 KTR_LOG(kernentry_fork_ret
, lp
->lwp_proc
->p_pid
, lp
->lwp_tid
);
1273 * Simplified back end of syscall(), used when returning from fork()
1274 * directly into user mode.
1276 * This code will return back into the fork trampoline code which then
1279 * NOTE: The mplock is not held at any point.
1282 generic_lwp_return(struct lwp
*lp
, struct trapframe
*frame
)
1284 struct proc
*p
= lp
->lwp_proc
;
1287 * Check for exit-race. If one lwp exits the process concurrent with
1288 * another lwp creating a new thread, the two operations may cross
1289 * each other resulting in the newly-created lwp not receiving a
1292 if (p
->p_flags
& P_WEXIT
) {
1293 lwpsignal(p
, lp
, SIGKILL
);
1297 * Newly forked processes are given a kernel priority. We have to
1298 * adjust the priority to a normal user priority and fake entry
1299 * into the kernel (call userenter()) to install a passive release
1300 * function just in case userret() decides to stop the process. This
1301 * can occur when ^Z races a fork. If we do not install the passive
1302 * release function the current process designation will not be
1303 * released when the thread goes to sleep.
1305 lwkt_setpri_self(TDPRI_USER_NORM
);
1306 userenter(lp
->lwp_thread
, p
);
1307 userret(lp
, frame
, 0);
1309 if (KTRPOINT(lp
->lwp_thread
, KTR_SYSRET
))
1310 ktrsysret(lp
, SYS_fork
, 0, 0);
1312 lp
->lwp_flags
|= LWP_PASSIVE_ACQ
;
1314 lp
->lwp_flags
&= ~LWP_PASSIVE_ACQ
;
1318 * doreti has turned into this. The frame is directly on the stack. We
1319 * pull everything else we need (fpu and tls context) from the current
1322 * Note on fpu interactions: In a virtual kernel, the fpu context for
1323 * an emulated user mode process is not shared with the virtual kernel's
1324 * fpu context, so we only have to 'stack' fpu contexts within the virtual
1325 * kernel itself, and not even then since the signal() contexts that we care
1326 * about save and restore the FPU state (I think anyhow).
1328 * vmspace_ctl() returns an error only if it had problems instaling the
1329 * context we supplied or problems copying data to/from our VM space.
1332 go_user(struct intrframe
*frame
)
1334 struct trapframe
*tf
= (void *)&frame
->if_rdi
;
1340 * Interrupts may be disabled on entry, make sure all signals
1341 * can be received before beginning our loop.
1346 * Switch to the current simulated user process, then call
1347 * user_trap() when we break out of it (usually due to a signal).
1352 * Always make the FPU state correct. This should generally
1353 * be faster because the cost of taking a #NM fault through
1354 * the vkernel to the real kernel is astronomical.
1357 tf
->tf_xflags
&= ~PGEX_FPFAULT
;
1358 if (mdcpu
->gd_npxthread
!= curthread
) {
1359 if (mdcpu
->gd_npxthread
)
1360 npxsave(mdcpu
->gd_npxthread
->td_savefpu
);
1365 * Tell the real kernel whether it is ok to use the FP
1366 * unit or not, allowing us to take a T_DNA exception
1367 * if the context tries to use the FP.
1369 if (mdcpu
->gd_npxthread
== curthread
) {
1370 tf
->tf_xflags
&= ~PGEX_FPFAULT
;
1372 tf
->tf_xflags
|= PGEX_FPFAULT
;
1377 * Run emulated user process context. This call interlocks
1378 * with new mailbox signals.
1380 * Set PGEX_U unconditionally, indicating a user frame (the
1381 * bit is normally set only by T_PAGEFLT).
1384 id
= (void *)vtophys(curproc
->p_vmspace
->vm_pmap
.pm_pml4
);
1386 id
= &curproc
->p_vmspace
->vm_pmap
;
1389 * The GDF_VIRTUSER hack helps statclock() figure out who
1390 * the tick belongs to.
1393 gd
->gd_flags
|= GDF_VIRTUSER
;
1394 r
= vmspace_ctl(id
, VMSPACE_CTL_RUN
, tf
,
1395 &curthread
->td_savevext
);
1396 gd
->gd_flags
&= ~GDF_VIRTUSER
;
1398 frame
->if_xflags
|= PGEX_U
;
1401 * Immediately save the user FPU state. The vkernel is a
1402 * user program and libraries like libc will use the FP
1405 if (mdcpu
->gd_npxthread
== curthread
) {
1406 npxsave(mdcpu
->gd_npxthread
->td_savefpu
);
1410 kprintf("GO USER %d trap %ld EVA %08lx RIP %08lx RSP %08lx XFLAGS %02lx/%02lx\n",
1411 r
, tf
->tf_trapno
, tf
->tf_addr
, tf
->tf_rip
, tf
->tf_rsp
,
1412 tf
->tf_xflags
, frame
->if_xflags
);
1416 panic("vmspace_ctl failed error %d", errno
);
1418 if (tf
->tf_trapno
) {
1422 if (mycpu
->gd_reqflags
& RQF_AST_MASK
) {
1423 tf
->tf_trapno
= T_ASTFLT
;
1431 * If PGEX_FPFAULT is set then set FP_VIRTFP in the PCB to force a T_DNA
1432 * fault (which is then passed back to the virtual kernel) if an attempt is
1433 * made to use the FP unit.
1435 * XXX this is a fairly big hack.
1438 set_vkernel_fp(struct trapframe
*frame
)
1440 struct thread
*td
= curthread
;
1442 if (frame
->tf_xflags
& PGEX_FPFAULT
) {
1443 td
->td_pcb
->pcb_flags
|= FP_VIRTFP
;
1444 if (mdcpu
->gd_npxthread
== td
)
1447 td
->td_pcb
->pcb_flags
&= ~FP_VIRTFP
;
1452 * Called from vkernel_trap() to fixup the vkernel's syscall
1453 * frame for vmspace_ctl() return.
1456 cpu_vkernel_trap(struct trapframe
*frame
, int error
)
1458 frame
->tf_rax
= error
;
1460 frame
->tf_rflags
|= PSL_C
;
1462 frame
->tf_rflags
&= ~PSL_C
;