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/pc32/i386/trap.c,v 1.115 2008/09/09 04:06:17 dillon Exp $
43 * 386 Trap and System call handling
51 #include "opt_ktrace.h"
52 #include "opt_clock.h"
55 #include <sys/param.h>
56 #include <sys/systm.h>
58 #include <sys/pioctl.h>
59 #include <sys/kernel.h>
60 #include <sys/resourcevar.h>
61 #include <sys/signalvar.h>
62 #include <sys/signal2.h>
63 #include <sys/syscall.h>
64 #include <sys/sysctl.h>
65 #include <sys/sysent.h>
67 #include <sys/vmmeter.h>
68 #include <sys/malloc.h>
70 #include <sys/ktrace.h>
73 #include <sys/upcall.h>
74 #include <sys/vkernel.h>
75 #include <sys/sysproto.h>
76 #include <sys/sysunion.h>
79 #include <vm/vm_param.h>
82 #include <vm/vm_kern.h>
83 #include <vm/vm_map.h>
84 #include <vm/vm_page.h>
85 #include <vm/vm_extern.h>
87 #include <machine/cpu.h>
88 #include <machine/md_var.h>
89 #include <machine/pcb.h>
90 #include <machine/smp.h>
91 #include <machine/tss.h>
92 #include <machine/specialreg.h>
93 #include <machine/globaldata.h>
95 #include <machine_base/isa/intr_machdep.h>
98 #include <sys/syslog.h>
99 #include <machine/clock.h>
102 #include <machine/vm86.h>
105 #include <sys/msgport2.h>
106 #include <sys/thread2.h>
110 #define MAKEMPSAFE(have_mplock) \
111 if (have_mplock == 0) { \
118 #define MAKEMPSAFE(have_mplock)
122 int (*pmath_emulate) (struct trapframe *);
124 extern void trap (struct trapframe *frame);
125 extern int trapwrite (unsigned addr);
126 extern void syscall2 (struct trapframe *frame);
128 static int trap_pfault (struct trapframe *, int, vm_offset_t);
129 static void trap_fatal (struct trapframe *, vm_offset_t);
130 void dblfault_handler (void);
132 extern inthand_t IDTVEC(syscall);
134 #define MAX_TRAP_MSG 28
135 static char *trap_msg[] = {
137 "privileged instruction fault", /* 1 T_PRIVINFLT */
139 "breakpoint instruction fault", /* 3 T_BPTFLT */
142 "arithmetic trap", /* 6 T_ARITHTRAP */
143 "system forced exception", /* 7 T_ASTFLT */
145 "general protection fault", /* 9 T_PROTFLT */
146 "trace trap", /* 10 T_TRCTRAP */
148 "page fault", /* 12 T_PAGEFLT */
150 "alignment fault", /* 14 T_ALIGNFLT */
154 "integer divide fault", /* 18 T_DIVIDE */
155 "non-maskable interrupt trap", /* 19 T_NMI */
156 "overflow trap", /* 20 T_OFLOW */
157 "FPU bounds check fault", /* 21 T_BOUND */
158 "FPU device not available", /* 22 T_DNA */
159 "double fault", /* 23 T_DOUBLEFLT */
160 "FPU operand fetch fault", /* 24 T_FPOPFLT */
161 "invalid TSS fault", /* 25 T_TSSFLT */
162 "segment not present fault", /* 26 T_SEGNPFLT */
163 "stack fault", /* 27 T_STKFLT */
164 "machine check trap", /* 28 T_MCHK */
167 #if defined(I586_CPU) && !defined(NO_F00F_HACK)
168 extern int has_f00f_bug;
172 static int ddb_on_nmi = 1;
173 SYSCTL_INT(_machdep, OID_AUTO, ddb_on_nmi, CTLFLAG_RW,
174 &ddb_on_nmi, 0, "Go to DDB on NMI");
176 static int panic_on_nmi = 1;
177 SYSCTL_INT(_machdep, OID_AUTO, panic_on_nmi, CTLFLAG_RW,
178 &panic_on_nmi, 0, "Panic on NMI");
179 static int fast_release;
180 SYSCTL_INT(_machdep, OID_AUTO, fast_release, CTLFLAG_RW,
181 &fast_release, 0, "Passive Release was optimal");
182 static int slow_release;
183 SYSCTL_INT(_machdep, OID_AUTO, slow_release, CTLFLAG_RW,
184 &slow_release, 0, "Passive Release was nonoptimal");
186 static int syscall_mpsafe = 1;
187 SYSCTL_INT(_kern, OID_AUTO, syscall_mpsafe, CTLFLAG_RW,
188 &syscall_mpsafe, 0, "Allow MPSAFE marked syscalls to run without BGL");
189 TUNABLE_INT("kern.syscall_mpsafe", &syscall_mpsafe);
190 static int trap_mpsafe = 1;
191 SYSCTL_INT(_kern, OID_AUTO, trap_mpsafe, CTLFLAG_RW,
192 &trap_mpsafe, 0, "Allow traps to mostly run without the BGL");
193 TUNABLE_INT("kern.trap_mpsafe", &trap_mpsafe);
196 MALLOC_DEFINE(M_SYSMSG, "sysmsg", "sysmsg structure");
197 extern int max_sysmsg;
200 * Passive USER->KERNEL transition. This only occurs if we block in the
201 * kernel while still holding our userland priority. We have to fixup our
202 * priority in order to avoid potential deadlocks before we allow the system
203 * to switch us to another thread.
206 passive_release(struct thread *td)
208 struct lwp *lp = td->td_lwp;
210 td->td_release = NULL;
211 lwkt_setpri_self(TDPRI_KERN_USER);
212 lp->lwp_proc->p_usched->release_curproc(lp);
216 * userenter() passively intercepts the thread switch function to increase
217 * the thread priority from a user priority to a kernel priority, reducing
218 * syscall and trap overhead for the case where no switch occurs.
222 userenter(struct thread *curtd)
224 curtd->td_release = passive_release;
228 * Handle signals, upcalls, profiling, and other AST's and/or tasks that
229 * must be completed before we can return to or try to return to userland.
231 * Note that td_sticks is a 64 bit quantity, but there's no point doing 64
232 * arithmatic on the delta calculation so the absolute tick values are
233 * truncated to an integer.
236 userret(struct lwp *lp, struct trapframe *frame, int sticks)
238 struct proc *p = lp->lwp_proc;
242 * Charge system time if profiling. Note: times are in microseconds.
243 * This may do a copyout and block, so do it first even though it
244 * means some system time will be charged as user time.
246 if (p->p_flag & P_PROFIL) {
247 addupc_task(p, frame->tf_eip,
248 (u_int)((int)lp->lwp_thread->td_sticks - sticks));
253 * If the jungle wants us dead, so be it.
255 if (lp->lwp_flag & LWP_WEXIT) {
258 rel_mplock(); /* NOT REACHED */
262 * Block here if we are in a stopped state.
264 if (p->p_stat == SSTOP) {
272 * Post any pending upcalls. If running a virtual kernel be sure
273 * to restore the virtual kernel's vmspace before posting the upcall.
275 if (p->p_flag & P_UPCALLPEND) {
276 p->p_flag &= ~P_UPCALLPEND;
284 * Post any pending signals. If running a virtual kernel be sure
285 * to restore the virtual kernel's vmspace before posting the signal.
287 if ((sig = CURSIG(lp)) != 0) {
295 * block here if we are swapped out, but still process signals
296 * (such as SIGKILL). proc0 (the swapin scheduler) is already
297 * aware of our situation, we do not have to wake it up.
299 if (p->p_flag & P_SWAPPEDOUT) {
301 p->p_flag |= P_SWAPWAIT;
303 if (p->p_flag & P_SWAPWAIT)
304 tsleep(p, PCATCH, "SWOUT", 0);
305 p->p_flag &= ~P_SWAPWAIT;
311 * Make sure postsig() handled request to restore old signal mask after
312 * running signal handler.
314 KKASSERT((lp->lwp_flag & LWP_OLDMASK) == 0);
318 * Cleanup from userenter and any passive release that might have occured.
319 * We must reclaim the current-process designation before we can return
320 * to usermode. We also handle both LWKT and USER reschedule requests.
323 userexit(struct lwp *lp)
325 struct thread *td = lp->lwp_thread;
326 /* globaldata_t gd = td->td_gd; */
329 * Handle stop requests at kernel priority. Any requests queued
330 * after this loop will generate another AST.
332 while (lp->lwp_proc->p_stat == SSTOP) {
339 * Reduce our priority in preparation for a return to userland. If
340 * our passive release function was still in place, our priority was
341 * never raised and does not need to be reduced.
343 if (td->td_release == NULL)
344 lwkt_setpri_self(TDPRI_USER_NORM);
345 td->td_release = NULL;
348 * Become the current user scheduled process if we aren't already,
349 * and deal with reschedule requests and other factors.
351 lp->lwp_proc->p_usched->acquire_curproc(lp);
352 /* WARNING: we may have migrated cpu's */
353 /* gd = td->td_gd; */
356 #if !defined(KTR_KERNENTRY)
357 #define KTR_KERNENTRY KTR_ALL
359 KTR_INFO_MASTER(kernentry);
360 KTR_INFO(KTR_KERNENTRY, kernentry, trap, 0, "pid=%d, tid=%d, trapno=%d, eva=%p",
361 sizeof(int) + sizeof(int) + sizeof(int) + sizeof(vm_offset_t));
362 KTR_INFO(KTR_KERNENTRY, kernentry, trap_ret, 0, "pid=%d, tid=%d",
363 sizeof(int) + sizeof(int));
364 KTR_INFO(KTR_KERNENTRY, kernentry, syscall, 0, "pid=%d, tid=%d, call=%d",
365 sizeof(int) + sizeof(int) + sizeof(int));
366 KTR_INFO(KTR_KERNENTRY, kernentry, syscall_ret, 0, "pid=%d, tid=%d, err=%d",
367 sizeof(int) + sizeof(int) + sizeof(int));
368 KTR_INFO(KTR_KERNENTRY, kernentry, fork_ret, 0, "pid=%d, tid=%d",
369 sizeof(int) + sizeof(int));
372 * Exception, fault, and trap interface to the kernel.
373 * This common code is called from assembly language IDT gate entry
374 * routines that prepare a suitable stack frame, and restore this
375 * frame after the exception has been processed.
377 * This function is also called from doreti in an interlock to handle ASTs.
378 * For example: hardwareint->INTROUTINE->(set ast)->doreti->trap
380 * NOTE! We have to retrieve the fault address prior to obtaining the
381 * MP lock because get_mplock() may switch out. YYY cr2 really ought
382 * to be retrieved by the assembly code, not here.
384 * XXX gd_trap_nesting_level currently prevents lwkt_switch() from panicing
385 * if an attempt is made to switch from a fast interrupt or IPI. This is
386 * necessary to properly take fatal kernel traps on SMP machines if
387 * get_mplock() has to block.
391 trap(struct trapframe *frame)
393 struct globaldata *gd = mycpu;
394 struct thread *td = gd->gd_curthread;
395 struct lwp *lp = td->td_lwp;
398 int i = 0, ucode = 0, type, code;
403 int crit_count = td->td_pri & ~TDPRI_MASK;
410 eva = (frame->tf_trapno == T_PAGEFLT ? rcr2() : 0);
411 ++gd->gd_trap_nesting_level;
412 MAKEMPSAFE(have_mplock);
413 trap_fatal(frame, eva);
414 --gd->gd_trap_nesting_level;
420 ++gd->gd_trap_nesting_level;
421 if (frame->tf_trapno == T_PAGEFLT) {
423 * For some Cyrix CPUs, %cr2 is clobbered by interrupts.
424 * This problem is worked around by using an interrupt
425 * gate for the pagefault handler. We are finally ready
426 * to read %cr2 and then must reenable interrupts.
428 * XXX this should be in the switch statement, but the
429 * NO_FOOF_HACK and VM86 goto and ifdefs obfuscate the
430 * flow of control too much for this to be obviously
438 if (trap_mpsafe == 0)
439 MAKEMPSAFE(have_mplock);
442 --gd->gd_trap_nesting_level;
444 if (!(frame->tf_eflags & PSL_I)) {
446 * Buggy application or kernel code has disabled interrupts
447 * and then trapped. Enabling interrupts now is wrong, but
448 * it is better than running with interrupts disabled until
449 * they are accidentally enabled later.
451 type = frame->tf_trapno;
452 if (ISPL(frame->tf_cs)==SEL_UPL || (frame->tf_eflags & PSL_VM)) {
453 MAKEMPSAFE(have_mplock);
455 "pid %ld (%s): trap %d with interrupts disabled\n",
456 (long)curproc->p_pid, curproc->p_comm, type);
457 } else if (type != T_BPTFLT && type != T_TRCTRAP) {
459 * XXX not quite right, since this may be for a
460 * multiple fault in user mode.
462 MAKEMPSAFE(have_mplock);
463 kprintf("kernel trap %d with interrupts disabled\n",
469 #if defined(I586_CPU) && !defined(NO_F00F_HACK)
472 type = frame->tf_trapno;
473 code = frame->tf_err;
476 if (frame->tf_eflags & PSL_VM &&
477 (type == T_PROTFLT || type == T_STKFLT)) {
479 KKASSERT(td->td_mpcount > 0);
481 i = vm86_emulate((struct vm86frame *)frame);
483 KKASSERT(td->td_mpcount > 0);
487 * returns to original process
490 vm86_trap((struct vm86frame *)frame,
493 vm86_trap((struct vm86frame *)frame, 0);
495 KKASSERT(0); /* NOT REACHED */
501 * these traps want either a process context, or
502 * assume a normal userspace trap.
506 trap_fatal(frame, eva);
509 type = T_BPTFLT; /* kernel breakpoint */
512 goto kernel_trap; /* normal kernel trap handling */
515 if ((ISPL(frame->tf_cs) == SEL_UPL) || (frame->tf_eflags & PSL_VM)) {
518 KTR_LOG(kernentry_trap, p->p_pid, lp->lwp_tid,
519 frame->tf_trapno, eva);
523 sticks = (int)td->td_sticks;
524 lp->lwp_md.md_regs = frame;
527 case T_PRIVINFLT: /* privileged instruction fault */
532 case T_BPTFLT: /* bpt instruction fault */
533 case T_TRCTRAP: /* trace trap */
534 frame->tf_eflags &= ~PSL_T;
538 case T_ARITHTRAP: /* arithmetic trap */
543 case T_ASTFLT: /* Allow process switch */
544 mycpu->gd_cnt.v_soft++;
545 if (mycpu->gd_reqflags & RQF_AST_OWEUPC) {
546 atomic_clear_int_nonlocked(&mycpu->gd_reqflags,
548 addupc_task(p, p->p_prof.pr_addr,
554 * The following two traps can happen in
555 * vm86 mode, and, if so, we want to handle
558 case T_PROTFLT: /* general protection fault */
559 case T_STKFLT: /* stack fault */
560 if (frame->tf_eflags & PSL_VM) {
561 i = vm86_emulate((struct vm86frame *)frame);
568 case T_SEGNPFLT: /* segment not present fault */
569 case T_TSSFLT: /* invalid TSS fault */
570 case T_DOUBLEFLT: /* double fault */
572 ucode = code + BUS_SEGM_FAULT ;
576 case T_PAGEFLT: /* page fault */
577 MAKEMPSAFE(have_mplock);
578 i = trap_pfault(frame, TRUE, eva);
581 #if defined(I586_CPU) && !defined(NO_F00F_HACK)
591 case T_DIVIDE: /* integer divide fault */
598 MAKEMPSAFE(have_mplock);
600 goto handle_powerfail;
601 #else /* !POWERFAIL_NMI */
602 /* machine/parity/power fail/"kitchen sink" faults */
603 if (isa_nmi(code) == 0) {
606 * NMI can be hooked up to a pushbutton
610 kprintf ("NMI ... going to debugger\n");
611 kdb_trap (type, 0, frame);
615 } else if (panic_on_nmi)
616 panic("NMI indicates hardware failure");
618 #endif /* POWERFAIL_NMI */
619 #endif /* NISA > 0 */
621 case T_OFLOW: /* integer overflow fault */
626 case T_BOUND: /* bounds check fault */
633 * Virtual kernel intercept - pass the DNA exception
634 * to the virtual kernel if it asked to handle it.
635 * This occurs when the virtual kernel is holding
636 * onto the FP context for a different emulated
637 * process then the one currently running.
639 * We must still call npxdna() since we may have
640 * saved FP state that the virtual kernel needs
641 * to hand over to a different emulated process.
643 if (lp->lwp_vkernel && lp->lwp_vkernel->ve &&
644 (td->td_pcb->pcb_flags & FP_VIRTFP)
652 * The kernel may have switched out the FP unit's
653 * state, causing the user process to take a fault
654 * when it tries to use the FP unit. Restore the
660 if (!pmath_emulate) {
662 ucode = FPE_FPU_NP_TRAP;
665 i = (*pmath_emulate)(frame);
667 if (!(frame->tf_eflags & PSL_T))
669 frame->tf_eflags &= ~PSL_T;
672 /* else ucode = emulator_only_knows() XXX */
675 case T_FPOPFLT: /* FPU operand fetch fault */
680 case T_XMMFLT: /* SIMD floating-point exception */
690 case T_PAGEFLT: /* page fault */
691 MAKEMPSAFE(have_mplock);
692 trap_pfault(frame, FALSE, eva);
698 * The kernel may be using npx for copying or other
706 case T_PROTFLT: /* general protection fault */
707 case T_SEGNPFLT: /* segment not present fault */
709 * Invalid segment selectors and out of bounds
710 * %eip's and %esp's can be set up in user mode.
711 * This causes a fault in kernel mode when the
712 * kernel tries to return to user mode. We want
713 * to get this fault so that we can fix the
714 * problem here and not have to check all the
715 * selectors and pointers when the user changes
718 #define MAYBE_DORETI_FAULT(where, whereto) \
720 if (frame->tf_eip == (int)where) { \
721 frame->tf_eip = (int)whereto; \
725 if (mycpu->gd_intr_nesting_level == 0) {
727 * Invalid %fs's and %gs's can be created using
728 * procfs or PT_SETREGS or by invalidating the
729 * underlying LDT entry. This causes a fault
730 * in kernel mode when the kernel attempts to
731 * switch contexts. Lose the bad context
732 * (XXX) so that we can continue, and generate
735 MAYBE_DORETI_FAULT(doreti_iret,
737 MAYBE_DORETI_FAULT(doreti_popl_ds,
738 doreti_popl_ds_fault);
739 MAYBE_DORETI_FAULT(doreti_popl_es,
740 doreti_popl_es_fault);
741 MAYBE_DORETI_FAULT(doreti_popl_fs,
742 doreti_popl_fs_fault);
743 MAYBE_DORETI_FAULT(doreti_popl_gs,
744 doreti_popl_gs_fault);
745 if (td->td_pcb->pcb_onfault) {
747 (register_t)td->td_pcb->pcb_onfault;
755 * PSL_NT can be set in user mode and isn't cleared
756 * automatically when the kernel is entered. This
757 * causes a TSS fault when the kernel attempts to
758 * `iret' because the TSS link is uninitialized. We
759 * want to get this fault so that we can fix the
760 * problem here and not every time the kernel is
763 if (frame->tf_eflags & PSL_NT) {
764 frame->tf_eflags &= ~PSL_NT;
769 case T_TRCTRAP: /* trace trap */
770 if (frame->tf_eip == (int)IDTVEC(syscall)) {
772 * We've just entered system mode via the
773 * syscall lcall. Continue single stepping
774 * silently until the syscall handler has
779 if (frame->tf_eip == (int)IDTVEC(syscall) + 1) {
781 * The syscall handler has now saved the
782 * flags. Stop single stepping it.
784 frame->tf_eflags &= ~PSL_T;
788 * Ignore debug register trace traps due to
789 * accesses in the user's address space, which
790 * can happen under several conditions such as
791 * if a user sets a watchpoint on a buffer and
792 * then passes that buffer to a system call.
793 * We still want to get TRCTRAPS for addresses
794 * in kernel space because that is useful when
795 * debugging the kernel.
797 if (user_dbreg_trap()) {
799 * Reset breakpoint bits because the
802 load_dr6(rdr6() & 0xfffffff0);
806 * Fall through (TRCTRAP kernel mode, kernel address)
810 * If DDB is enabled, let it handle the debugger trap.
811 * Otherwise, debugger traps "can't happen".
814 MAKEMPSAFE(have_mplock);
815 if (kdb_trap (type, 0, frame))
822 MAKEMPSAFE(have_mplock);
825 # define TIMER_FREQ 1193182
829 static unsigned lastalert = 0;
831 if(time_second - lastalert > 10)
833 log(LOG_WARNING, "NMI: power fail\n");
834 sysbeep(TIMER_FREQ/880, hz);
835 lastalert = time_second;
840 #else /* !POWERFAIL_NMI */
841 /* machine/parity/power fail/"kitchen sink" faults */
842 if (isa_nmi(code) == 0) {
845 * NMI can be hooked up to a pushbutton
849 kprintf ("NMI ... going to debugger\n");
850 kdb_trap (type, 0, frame);
854 } else if (panic_on_nmi == 0)
857 #endif /* POWERFAIL_NMI */
858 #endif /* NISA > 0 */
861 MAKEMPSAFE(have_mplock);
862 trap_fatal(frame, eva);
867 * Virtual kernel intercept - if the fault is directly related to a
868 * VM context managed by a virtual kernel then let the virtual kernel
871 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) {
872 vkernel_trap(lp, frame);
877 * Translate fault for emulators (e.g. Linux)
879 if (*p->p_sysent->sv_transtrap)
880 i = (*p->p_sysent->sv_transtrap)(i, type);
882 MAKEMPSAFE(have_mplock);
883 trapsignal(lp, i, ucode);
886 if (type <= MAX_TRAP_MSG) {
887 uprintf("fatal process exception: %s",
889 if ((type == T_PAGEFLT) || (type == T_PROTFLT))
890 uprintf(", fault VA = 0x%lx", (u_long)eva);
897 if (ISPL(frame->tf_cs) == SEL_UPL)
898 KASSERT(td->td_mpcount == have_mplock, ("badmpcount trap/end from %p", (void *)frame->tf_eip));
900 userret(lp, frame, sticks);
907 if (p != NULL && lp != NULL)
908 KTR_LOG(kernentry_trap_ret, p->p_pid, lp->lwp_tid);
910 KASSERT(crit_count == (td->td_pri & ~TDPRI_MASK),
911 ("syscall: critical section count mismatch! %d/%d",
912 crit_count / TDPRI_CRIT, td->td_pri / TDPRI_CRIT));
917 trap_pfault(struct trapframe *frame, int usermode, vm_offset_t eva)
920 struct vmspace *vm = NULL;
924 thread_t td = curthread;
925 struct lwp *lp = td->td_lwp;
927 va = trunc_page(eva);
928 if (va >= KERNBASE) {
930 * Don't allow user-mode faults in kernel address space.
931 * An exception: if the faulting address is the invalid
932 * instruction entry in the IDT, then the Intel Pentium
933 * F00F bug workaround was triggered, and we need to
934 * treat it is as an illegal instruction, and not a page
937 #if defined(I586_CPU) && !defined(NO_F00F_HACK)
938 if ((eva == (unsigned int)&idt[6]) && has_f00f_bug) {
939 frame->tf_trapno = T_PRIVINFLT;
949 * This is a fault on non-kernel virtual memory.
950 * vm is initialized above to NULL. If curproc is NULL
951 * or curproc->p_vmspace is NULL the fault is fatal.
954 vm = lp->lwp_vmspace;
962 if (frame->tf_err & PGEX_W)
963 ftype = VM_PROT_WRITE;
965 ftype = VM_PROT_READ;
967 if (map != &kernel_map) {
969 * Keep swapout from messing with us during this
975 * Grow the stack if necessary
977 /* grow_stack returns false only if va falls into
978 * a growable stack region and the stack growth
979 * fails. It returns true if va was not within
980 * a growable stack region, or if the stack
983 if (!grow_stack(lp->lwp_proc, va)) {
989 /* Fault in the user page: */
990 rv = vm_fault(map, va, ftype,
991 (ftype & VM_PROT_WRITE) ? VM_FAULT_DIRTY
997 * Don't have to worry about process locking or stacks
1000 rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL);
1003 if (rv == KERN_SUCCESS)
1007 if (td->td_gd->gd_intr_nesting_level == 0 &&
1008 td->td_pcb->pcb_onfault) {
1009 frame->tf_eip = (register_t)td->td_pcb->pcb_onfault;
1012 trap_fatal(frame, eva);
1016 /* kludge to pass faulting virtual address to sendsig */
1017 frame->tf_xflags = frame->tf_err;
1018 frame->tf_err = eva;
1020 return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV);
1024 trap_fatal(struct trapframe *frame, vm_offset_t eva)
1026 int code, type, ss, esp;
1027 struct soft_segment_descriptor softseg;
1029 code = frame->tf_err;
1030 type = frame->tf_trapno;
1031 sdtossd(&gdt[mycpu->gd_cpuid * NGDT + IDXSEL(frame->tf_cs & 0xffff)].sd, &softseg);
1033 if (type <= MAX_TRAP_MSG)
1034 kprintf("\n\nFatal trap %d: %s while in %s mode\n",
1035 type, trap_msg[type],
1036 frame->tf_eflags & PSL_VM ? "vm86" :
1037 ISPL(frame->tf_cs) == SEL_UPL ? "user" : "kernel");
1039 /* three separate prints in case of a trap on an unmapped page */
1040 kprintf("mp_lock = %08x; ", mp_lock);
1041 kprintf("cpuid = %d; ", mycpu->gd_cpuid);
1042 kprintf("lapic.id = %08x\n", lapic.id);
1044 if (type == T_PAGEFLT) {
1045 kprintf("fault virtual address = 0x%x\n", eva);
1046 kprintf("fault code = %s %s, %s\n",
1047 code & PGEX_U ? "user" : "supervisor",
1048 code & PGEX_W ? "write" : "read",
1049 code & PGEX_P ? "protection violation" : "page not present");
1051 kprintf("instruction pointer = 0x%x:0x%x\n",
1052 frame->tf_cs & 0xffff, frame->tf_eip);
1053 if ((ISPL(frame->tf_cs) == SEL_UPL) || (frame->tf_eflags & PSL_VM)) {
1054 ss = frame->tf_ss & 0xffff;
1055 esp = frame->tf_esp;
1057 ss = GSEL(GDATA_SEL, SEL_KPL);
1058 esp = (int)&frame->tf_esp;
1060 kprintf("stack pointer = 0x%x:0x%x\n", ss, esp);
1061 kprintf("frame pointer = 0x%x:0x%x\n", ss, frame->tf_ebp);
1062 kprintf("code segment = base 0x%x, limit 0x%x, type 0x%x\n",
1063 softseg.ssd_base, softseg.ssd_limit, softseg.ssd_type);
1064 kprintf(" = DPL %d, pres %d, def32 %d, gran %d\n",
1065 softseg.ssd_dpl, softseg.ssd_p, softseg.ssd_def32,
1067 kprintf("processor eflags = ");
1068 if (frame->tf_eflags & PSL_T)
1069 kprintf("trace trap, ");
1070 if (frame->tf_eflags & PSL_I)
1071 kprintf("interrupt enabled, ");
1072 if (frame->tf_eflags & PSL_NT)
1073 kprintf("nested task, ");
1074 if (frame->tf_eflags & PSL_RF)
1075 kprintf("resume, ");
1076 if (frame->tf_eflags & PSL_VM)
1078 kprintf("IOPL = %d\n", (frame->tf_eflags & PSL_IOPL) >> 12);
1079 kprintf("current process = ");
1081 kprintf("%lu (%s)\n",
1082 (u_long)curproc->p_pid, curproc->p_comm ?
1083 curproc->p_comm : "");
1087 kprintf("current thread = pri %d ", curthread->td_pri);
1088 if (curthread->td_pri >= TDPRI_CRIT)
1094 * we probably SHOULD have stopped the other CPUs before now!
1095 * another CPU COULD have been touching cpl at this moment...
1097 kprintf(" <- SMP: XXX");
1106 if ((debugger_on_panic || db_active) && kdb_trap(type, code, frame))
1109 kprintf("trap number = %d\n", type);
1110 if (type <= MAX_TRAP_MSG)
1111 panic("%s", trap_msg[type]);
1113 panic("unknown/reserved trap");
1117 * Double fault handler. Called when a fault occurs while writing
1118 * a frame for a trap/exception onto the stack. This usually occurs
1119 * when the stack overflows (such is the case with infinite recursion,
1122 * XXX Note that the current PTD gets replaced by IdlePTD when the
1123 * task switch occurs. This means that the stack that was active at
1124 * the time of the double fault is not available at <kstack> unless
1125 * the machine was idle when the double fault occurred. The downside
1126 * of this is that "trace <ebp>" in ddb won't work.
1129 dblfault_handler(void)
1131 struct mdglobaldata *gd = mdcpu;
1133 kprintf("\nFatal double fault:\n");
1134 kprintf("eip = 0x%x\n", gd->gd_common_tss.tss_eip);
1135 kprintf("esp = 0x%x\n", gd->gd_common_tss.tss_esp);
1136 kprintf("ebp = 0x%x\n", gd->gd_common_tss.tss_ebp);
1138 /* three separate prints in case of a trap on an unmapped page */
1139 kprintf("mp_lock = %08x; ", mp_lock);
1140 kprintf("cpuid = %d; ", mycpu->gd_cpuid);
1141 kprintf("lapic.id = %08x\n", lapic.id);
1143 panic("double fault");
1147 * Compensate for 386 brain damage (missing URKR).
1148 * This is a little simpler than the pagefault handler in trap() because
1149 * it the page tables have already been faulted in and high addresses
1150 * are thrown out early for other reasons.
1153 trapwrite(unsigned addr)
1160 va = trunc_page((vm_offset_t)addr);
1162 * XXX - MAX is END. Changed > to >= for temp. fix.
1164 if (va >= VM_MAX_USER_ADDRESS)
1167 lp = curthread->td_lwp;
1168 vm = lp->lwp_vmspace;
1170 PHOLD(lp->lwp_proc);
1172 if (!grow_stack(lp->lwp_proc, va)) {
1173 PRELE(lp->lwp_proc);
1178 * fault the data page
1180 rv = vm_fault(&vm->vm_map, va, VM_PROT_WRITE, VM_FAULT_DIRTY);
1182 PRELE(lp->lwp_proc);
1184 if (rv != KERN_SUCCESS)
1191 * syscall2 - MP aware system call request C handler
1193 * A system call is essentially treated as a trap except that the
1194 * MP lock is not held on entry or return. We are responsible for
1195 * obtaining the MP lock if necessary and for handling ASTs
1196 * (e.g. a task switch) prior to return.
1198 * In general, only simple access and manipulation of curproc and
1199 * the current stack is allowed without having to hold MP lock.
1201 * MPSAFE - note that large sections of this routine are run without
1206 syscall2(struct trapframe *frame)
1208 struct thread *td = curthread;
1209 struct proc *p = td->td_proc;
1210 struct lwp *lp = td->td_lwp;
1212 struct sysent *callp;
1213 register_t orig_tf_eflags;
1218 int crit_count = td->td_pri & ~TDPRI_MASK;
1221 int have_mplock = 0;
1224 union sysunion args;
1227 if (ISPL(frame->tf_cs) != SEL_UPL) {
1234 KTR_LOG(kernentry_syscall, p->p_pid, lp->lwp_tid,
1238 KASSERT(td->td_mpcount == 0, ("badmpcount syscall2 from %p", (void *)frame->tf_eip));
1239 if (syscall_mpsafe == 0)
1240 MAKEMPSAFE(have_mplock);
1242 userenter(td); /* lazy raise our priority */
1247 sticks = (int)td->td_sticks;
1248 orig_tf_eflags = frame->tf_eflags;
1251 * Virtual kernel intercept - if a VM context managed by a virtual
1252 * kernel issues a system call the virtual kernel handles it, not us.
1253 * Restore the virtual kernel context and return from its system
1254 * call. The current frame is copied out to the virtual kernel.
1256 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) {
1257 error = vkernel_trap(lp, frame);
1258 frame->tf_eax = error;
1260 frame->tf_eflags |= PSL_C;
1261 error = EJUSTRETURN;
1266 * Get the system call parameters and account for time
1268 lp->lwp_md.md_regs = frame;
1269 params = (caddr_t)frame->tf_esp + sizeof(int);
1270 code = frame->tf_eax;
1272 if (p->p_sysent->sv_prepsyscall) {
1273 (*p->p_sysent->sv_prepsyscall)(
1274 frame, (int *)(&args.nosys.sysmsg + 1),
1278 * Need to check if this is a 32 bit or 64 bit syscall.
1279 * fuword is MP aware.
1281 if (code == SYS_syscall) {
1283 * Code is first argument, followed by actual args.
1285 code = fuword(params);
1286 params += sizeof(int);
1287 } else if (code == SYS___syscall) {
1289 * Like syscall, but code is a quad, so as to maintain
1290 * quad alignment for the rest of the arguments.
1292 code = fuword(params);
1293 params += sizeof(quad_t);
1297 code &= p->p_sysent->sv_mask;
1298 if (code >= p->p_sysent->sv_size)
1299 callp = &p->p_sysent->sv_table[0];
1301 callp = &p->p_sysent->sv_table[code];
1303 narg = callp->sy_narg & SYF_ARGMASK;
1306 * copyin is MP aware, but the tracing code is not
1308 if (narg && params) {
1309 error = copyin(params, (caddr_t)(&args.nosys.sysmsg + 1),
1310 narg * sizeof(register_t));
1313 if (KTRPOINT(td, KTR_SYSCALL)) {
1314 MAKEMPSAFE(have_mplock);
1316 ktrsyscall(lp, code, narg,
1317 (void *)(&args.nosys.sysmsg + 1));
1325 if (KTRPOINT(td, KTR_SYSCALL)) {
1326 MAKEMPSAFE(have_mplock);
1327 ktrsyscall(lp, code, narg, (void *)(&args.nosys.sysmsg + 1));
1332 * For traditional syscall code edx is left untouched when 32 bit
1333 * results are returned. Since edx is loaded from fds[1] when the
1334 * system call returns we pre-set it here.
1336 args.sysmsg_fds[0] = 0;
1337 args.sysmsg_fds[1] = frame->tf_edx;
1340 * The syscall might manipulate the trap frame. If it does it
1341 * will probably return EJUSTRETURN.
1343 args.sysmsg_frame = frame;
1345 STOPEVENT(p, S_SCE, narg); /* MP aware */
1349 * Try to run the syscall without the MP lock if the syscall
1350 * is MP safe. We have to obtain the MP lock no matter what if
1353 if ((callp->sy_narg & SYF_MPSAFE) == 0)
1354 MAKEMPSAFE(have_mplock);
1357 error = (*callp->sy_call)(&args);
1361 * MP SAFE (we may or may not have the MP lock at this point)
1366 * Reinitialize proc pointer `p' as it may be different
1367 * if this is a child returning from fork syscall.
1370 lp = curthread->td_lwp;
1371 frame->tf_eax = args.sysmsg_fds[0];
1372 frame->tf_edx = args.sysmsg_fds[1];
1373 frame->tf_eflags &= ~PSL_C;
1377 * Reconstruct pc, assuming lcall $X,y is 7 bytes,
1378 * int 0x80 is 2 bytes. We saved this in tf_err.
1380 frame->tf_eip -= frame->tf_err;
1385 panic("Unexpected EASYNC return value (for now)");
1388 if (p->p_sysent->sv_errsize) {
1389 if (error >= p->p_sysent->sv_errsize)
1390 error = -1; /* XXX */
1392 error = p->p_sysent->sv_errtbl[error];
1394 frame->tf_eax = error;
1395 frame->tf_eflags |= PSL_C;
1400 * Traced syscall. trapsignal() is not MP aware.
1402 if ((orig_tf_eflags & PSL_T) && !(orig_tf_eflags & PSL_VM)) {
1403 MAKEMPSAFE(have_mplock);
1404 frame->tf_eflags &= ~PSL_T;
1405 trapsignal(lp, SIGTRAP, 0);
1409 * Handle reschedule and other end-of-syscall issues
1411 userret(lp, frame, sticks);
1414 if (KTRPOINT(td, KTR_SYSRET)) {
1415 MAKEMPSAFE(have_mplock);
1416 ktrsysret(lp, code, error, args.sysmsg_result);
1421 * This works because errno is findable through the
1422 * register set. If we ever support an emulation where this
1423 * is not the case, this code will need to be revisited.
1425 STOPEVENT(p, S_SCX, code);
1430 * Release the MP lock if we had to get it
1432 KASSERT(td->td_mpcount == have_mplock,
1433 ("badmpcount syscall2/end from %p", (void *)frame->tf_eip));
1437 KTR_LOG(kernentry_syscall_ret, p->p_pid, lp->lwp_tid, error);
1439 KASSERT(crit_count == (td->td_pri & ~TDPRI_MASK),
1440 ("syscall: critical section count mismatch! %d/%d",
1441 crit_count / TDPRI_CRIT, td->td_pri / TDPRI_CRIT));
1446 fork_return(struct lwp *lp, struct trapframe *frame)
1448 frame->tf_eax = 0; /* Child returns zero */
1449 frame->tf_eflags &= ~PSL_C; /* success */
1452 generic_lwp_return(lp, frame);
1453 KTR_LOG(kernentry_fork_ret, lp->lwp_proc->p_pid, lp->lwp_tid);
1457 * Simplified back end of syscall(), used when returning from fork()
1458 * directly into user mode. MP lock is held on entry and should be
1459 * released on return. This code will return back into the fork
1460 * trampoline code which then runs doreti.
1463 generic_lwp_return(struct lwp *lp, struct trapframe *frame)
1465 struct proc *p = lp->lwp_proc;
1468 * Newly forked processes are given a kernel priority. We have to
1469 * adjust the priority to a normal user priority and fake entry
1470 * into the kernel (call userenter()) to install a passive release
1471 * function just in case userret() decides to stop the process. This
1472 * can occur when ^Z races a fork. If we do not install the passive
1473 * release function the current process designation will not be
1474 * released when the thread goes to sleep.
1476 lwkt_setpri_self(TDPRI_USER_NORM);
1477 userenter(lp->lwp_thread);
1478 userret(lp, frame, 0);
1480 if (KTRPOINT(lp->lwp_thread, KTR_SYSRET))
1481 ktrsysret(lp, SYS_fork, 0, 0);
1483 p->p_flag |= P_PASSIVE_ACQ;
1485 p->p_flag &= ~P_PASSIVE_ACQ;
1487 KKASSERT(lp->lwp_thread->td_mpcount == 1);
1493 * If PGEX_FPFAULT is set then set FP_VIRTFP in the PCB to force a T_DNA
1494 * fault (which is then passed back to the virtual kernel) if an attempt is
1495 * made to use the FP unit.
1497 * XXX this is a fairly big hack.
1500 set_vkernel_fp(struct trapframe *frame)
1502 struct thread *td = curthread;
1504 if (frame->tf_xflags & PGEX_FPFAULT) {
1505 td->td_pcb->pcb_flags |= FP_VIRTFP;
1506 if (mdcpu->gd_npxthread == td)
1509 td->td_pcb->pcb_flags &= ~FP_VIRTFP;