2 * Copyright (c) 1990, 1993
3 * The Regents of the University of California. All rights reserved.
4 * Copyright (C) 1994, David Greenman
5 * Copyright (c) 2008 The DragonFly Project.
6 * Copyright (c) 2008 Jordan Gordeev.
8 * This code is derived from software contributed to Berkeley by
9 * the University of Utah, and William Jolitz.
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 * 3. All advertising materials mentioning features or use of this software
20 * must display the following acknowledgement:
21 * This product includes software developed by the University of
22 * California, Berkeley and its contributors.
23 * 4. Neither the name of the University nor the names of its contributors
24 * may be used to endorse or promote products derived from this software
25 * without specific prior written permission.
27 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
28 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
29 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
30 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
31 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
32 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
33 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
34 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
35 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
36 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
39 * from: @(#)trap.c 7.4 (Berkeley) 5/13/91
40 * $FreeBSD: src/sys/i386/i386/trap.c,v 1.147.2.11 2003/02/27 19:09:59 luoqi Exp $
44 * x86_64 Trap and System call handling
50 #include "opt_ktrace.h"
52 #include <machine/frame.h>
53 #include <sys/param.h>
54 #include <sys/systm.h>
55 #include <sys/kernel.h>
56 #include <sys/kerneldump.h>
58 #include <sys/pioctl.h>
59 #include <sys/types.h>
60 #include <sys/signal2.h>
61 #include <sys/syscall.h>
62 #include <sys/sysctl.h>
63 #include <sys/sysent.h>
64 #include <sys/systm.h>
66 #include <sys/ktrace.h>
69 #include <sys/sysmsg.h>
70 #include <sys/sysproto.h>
71 #include <sys/sysunion.h>
75 #include <vm/vm_extern.h>
76 #include <vm/vm_kern.h>
77 #include <vm/vm_param.h>
78 #include <machine/cpu.h>
79 #include <machine/pcb.h>
80 #include <machine/smp.h>
81 #include <machine/thread.h>
82 #include <machine/clock.h>
83 #include <machine/vmparam.h>
84 #include <machine/md_var.h>
85 #include <machine_base/isa/isa_intr.h>
86 #include <machine_base/apic/lapic.h>
90 #include <sys/thread2.h>
91 #include <sys/mplock2.h>
95 #define MAKEMPSAFE(have_mplock) \
96 if (have_mplock == 0) { \
103 #define MAKEMPSAFE(have_mplock)
107 extern void trap(struct trapframe *frame);
109 static int trap_pfault(struct trapframe *, int);
110 static void trap_fatal(struct trapframe *, vm_offset_t);
111 void dblfault_handler(struct trapframe *frame);
113 #define MAX_TRAP_MSG 30
114 static char *trap_msg[] = {
116 "privileged instruction fault", /* 1 T_PRIVINFLT */
118 "breakpoint instruction fault", /* 3 T_BPTFLT */
121 "arithmetic trap", /* 6 T_ARITHTRAP */
122 "system forced exception", /* 7 T_ASTFLT */
124 "general protection fault", /* 9 T_PROTFLT */
125 "trace trap", /* 10 T_TRCTRAP */
127 "page fault", /* 12 T_PAGEFLT */
129 "alignment fault", /* 14 T_ALIGNFLT */
133 "integer divide fault", /* 18 T_DIVIDE */
134 "non-maskable interrupt trap", /* 19 T_NMI */
135 "overflow trap", /* 20 T_OFLOW */
136 "FPU bounds check fault", /* 21 T_BOUND */
137 "FPU device not available", /* 22 T_DNA */
138 "double fault", /* 23 T_DOUBLEFLT */
139 "FPU operand fetch fault", /* 24 T_FPOPFLT */
140 "invalid TSS fault", /* 25 T_TSSFLT */
141 "segment not present fault", /* 26 T_SEGNPFLT */
142 "stack fault", /* 27 T_STKFLT */
143 "machine check trap", /* 28 T_MCHK */
144 "SIMD floating-point exception", /* 29 T_XMMFLT */
145 "reserved (unknown) fault", /* 30 T_RESERVED */
149 static int ddb_on_nmi = 1;
150 SYSCTL_INT(_machdep, OID_AUTO, ddb_on_nmi, CTLFLAG_RW,
151 &ddb_on_nmi, 0, "Go to DDB on NMI");
152 static int ddb_on_seg_fault = 0;
153 SYSCTL_INT(_machdep, OID_AUTO, ddb_on_seg_fault, CTLFLAG_RW,
154 &ddb_on_seg_fault, 0, "Go to DDB on user seg-fault");
155 static int freeze_on_seg_fault = 0;
156 SYSCTL_INT(_machdep, OID_AUTO, freeze_on_seg_fault, CTLFLAG_RW,
157 &freeze_on_seg_fault, 0, "Go to DDB on user seg-fault");
159 static int panic_on_nmi = 1;
160 SYSCTL_INT(_machdep, OID_AUTO, panic_on_nmi, CTLFLAG_RW,
161 &panic_on_nmi, 0, "Panic on NMI");
162 static int fast_release;
163 SYSCTL_INT(_machdep, OID_AUTO, fast_release, CTLFLAG_RW,
164 &fast_release, 0, "Passive Release was optimal");
165 static int slow_release;
166 SYSCTL_INT(_machdep, OID_AUTO, slow_release, CTLFLAG_RW,
167 &slow_release, 0, "Passive Release was nonoptimal");
170 * System call debugging records the worst-case system call
171 * overhead (inclusive of blocking), but may be inaccurate.
173 /*#define SYSCALL_DEBUG*/
175 uint64_t SysCallsWorstCase[SYS_MAXSYSCALL];
179 * Passively intercepts the thread switch function to increase
180 * the thread priority from a user priority to a kernel priority, reducing
181 * syscall and trap overhead for the case where no switch occurs.
183 * Synchronizes td_ucred with p_ucred. This is used by system calls,
184 * signal handling, faults, AST traps, and anything else that enters the
185 * kernel from userland and provides the kernel with a stable read-only
186 * copy of the process ucred.
189 userenter(struct thread *curtd, struct proc *curp)
194 curtd->td_release = lwkt_passive_release;
196 if (curtd->td_ucred != curp->p_ucred) {
197 ncred = crhold(curp->p_ucred);
198 ocred = curtd->td_ucred;
199 curtd->td_ucred = ncred;
206 * Debugging, remove top two user stack pages to catch kernel faults
208 if (freeze_on_seg_fault > 1 && curtd->td_lwp) {
209 pmap_remove(vmspace_pmap(curtd->td_lwp->lwp_vmspace),
210 0x00007FFFFFFFD000LU,
211 0x0000800000000000LU);
217 * Handle signals, upcalls, profiling, and other AST's and/or tasks that
218 * must be completed before we can return to or try to return to userland.
220 * Note that td_sticks is a 64 bit quantity, but there's no point doing 64
221 * arithmatic on the delta calculation so the absolute tick values are
222 * truncated to an integer.
225 userret(struct lwp *lp, struct trapframe *frame, int sticks)
227 struct proc *p = lp->lwp_proc;
231 * Charge system time if profiling. Note: times are in microseconds.
232 * This may do a copyout and block, so do it first even though it
233 * means some system time will be charged as user time.
235 if (p->p_flags & P_PROFIL) {
236 addupc_task(p, frame->tf_rip,
237 (u_int)((int)lp->lwp_thread->td_sticks - sticks));
242 * If the jungle wants us dead, so be it.
244 if (lp->lwp_mpflags & LWP_MP_WEXIT) {
245 lwkt_gettoken(&p->p_token);
247 lwkt_reltoken(&p->p_token); /* NOT REACHED */
251 * Block here if we are in a stopped state.
253 if (p->p_stat == SSTOP || dump_stop_usertds) {
254 lwkt_gettoken(&p->p_token);
256 lwkt_reltoken(&p->p_token);
261 * Post any pending upcalls. If running a virtual kernel be sure
262 * to restore the virtual kernel's vmspace before posting the upcall.
264 if (p->p_flags & (P_SIGVTALRM | P_SIGPROF | P_UPCALLPEND)) {
265 lwkt_gettoken(&p->p_token);
266 if (p->p_flags & P_SIGVTALRM) {
267 p->p_flags &= ~P_SIGVTALRM;
268 ksignal(p, SIGVTALRM);
270 if (p->p_flags & P_SIGPROF) {
271 p->p_flags &= ~P_SIGPROF;
274 if (p->p_flags & P_UPCALLPEND) {
275 p->p_flags &= ~P_UPCALLPEND;
278 lwkt_reltoken(&p->p_token);
283 * Post any pending signals. If running a virtual kernel be sure
284 * to restore the virtual kernel's vmspace before posting the signal.
286 * WARNING! postsig() can exit and not return.
288 if ((sig = CURSIG_TRACE(lp)) != 0) {
289 lwkt_gettoken(&p->p_token);
291 lwkt_reltoken(&p->p_token);
296 * block here if we are swapped out, but still process signals
297 * (such as SIGKILL). proc0 (the swapin scheduler) is already
298 * aware of our situation, we do not have to wake it up.
300 if (p->p_flags & P_SWAPPEDOUT) {
301 lwkt_gettoken(&p->p_token);
303 p->p_flags |= P_SWAPWAIT;
305 if (p->p_flags & P_SWAPWAIT)
306 tsleep(p, PCATCH, "SWOUT", 0);
307 p->p_flags &= ~P_SWAPWAIT;
309 lwkt_reltoken(&p->p_token);
314 * In a multi-threaded program it is possible for a thread to change
315 * signal state during a system call which temporarily changes the
316 * signal mask. In this case postsig() might not be run and we
317 * have to restore the mask ourselves.
319 if (lp->lwp_flags & LWP_OLDMASK) {
320 lp->lwp_flags &= ~LWP_OLDMASK;
321 lp->lwp_sigmask = lp->lwp_oldsigmask;
327 * Cleanup from userenter and any passive release that might have occured.
328 * We must reclaim the current-process designation before we can return
329 * to usermode. We also handle both LWKT and USER reschedule requests.
332 userexit(struct lwp *lp)
334 struct thread *td = lp->lwp_thread;
335 /* globaldata_t gd = td->td_gd; */
338 * Handle stop requests at kernel priority. Any requests queued
339 * after this loop will generate another AST.
341 while (lp->lwp_proc->p_stat == SSTOP) {
342 lwkt_gettoken(&lp->lwp_proc->p_token);
344 lwkt_reltoken(&lp->lwp_proc->p_token);
348 * Reduce our priority in preparation for a return to userland. If
349 * our passive release function was still in place, our priority was
350 * never raised and does not need to be reduced.
352 lwkt_passive_recover(td);
354 /* WARNING: we may have migrated cpu's */
355 /* gd = td->td_gd; */
358 * Become the current user scheduled process if we aren't already,
359 * and deal with reschedule requests and other factors.
361 lp->lwp_proc->p_usched->acquire_curproc(lp);
364 #if !defined(KTR_KERNENTRY)
365 #define KTR_KERNENTRY KTR_ALL
367 KTR_INFO_MASTER(kernentry);
368 KTR_INFO(KTR_KERNENTRY, kernentry, trap, 0,
369 "TRAP(pid %d, tid %d, trapno %ld, eva %lu)",
370 pid_t pid, lwpid_t tid, register_t trapno, vm_offset_t eva);
371 KTR_INFO(KTR_KERNENTRY, kernentry, trap_ret, 0, "TRAP_RET(pid %d, tid %d)",
372 pid_t pid, lwpid_t tid);
373 KTR_INFO(KTR_KERNENTRY, kernentry, syscall, 0, "SYSC(pid %d, tid %d, nr %ld)",
374 pid_t pid, lwpid_t tid, register_t trapno);
375 KTR_INFO(KTR_KERNENTRY, kernentry, syscall_ret, 0, "SYSRET(pid %d, tid %d, err %d)",
376 pid_t pid, lwpid_t tid, int err);
377 KTR_INFO(KTR_KERNENTRY, kernentry, fork_ret, 0, "FORKRET(pid %d, tid %d)",
378 pid_t pid, lwpid_t tid);
381 * Exception, fault, and trap interface to the kernel.
382 * This common code is called from assembly language IDT gate entry
383 * routines that prepare a suitable stack frame, and restore this
384 * frame after the exception has been processed.
386 * This function is also called from doreti in an interlock to handle ASTs.
387 * For example: hardwareint->INTROUTINE->(set ast)->doreti->trap
389 * NOTE! We have to retrieve the fault address prior to obtaining the
390 * MP lock because get_mplock() may switch out. YYY cr2 really ought
391 * to be retrieved by the assembly code, not here.
393 * XXX gd_trap_nesting_level currently prevents lwkt_switch() from panicing
394 * if an attempt is made to switch from a fast interrupt or IPI. This is
395 * necessary to properly take fatal kernel traps on SMP machines if
396 * get_mplock() has to block.
400 trap(struct trapframe *frame)
402 struct globaldata *gd = mycpu;
403 struct thread *td = gd->gd_curthread;
404 struct lwp *lp = td->td_lwp;
407 int i = 0, ucode = 0, type, code;
412 int crit_count = td->td_critcount;
413 lwkt_tokref_t curstop = td->td_toks_stop;
422 * We need to allow T_DNA faults when the debugger is active since
423 * some dumping paths do large bcopy() which use the floating
424 * point registers for faster copying.
426 if (db_active && frame->tf_trapno != T_DNA) {
427 eva = (frame->tf_trapno == T_PAGEFLT ? frame->tf_addr : 0);
428 ++gd->gd_trap_nesting_level;
429 MAKEMPSAFE(have_mplock);
430 trap_fatal(frame, eva);
431 --gd->gd_trap_nesting_level;
438 if ((frame->tf_rflags & PSL_I) == 0) {
440 * Buggy application or kernel code has disabled interrupts
441 * and then trapped. Enabling interrupts now is wrong, but
442 * it is better than running with interrupts disabled until
443 * they are accidentally enabled later.
445 type = frame->tf_trapno;
446 if (ISPL(frame->tf_cs) == SEL_UPL) {
447 MAKEMPSAFE(have_mplock);
448 /* JG curproc can be NULL */
450 "pid %ld (%s): trap %d with interrupts disabled\n",
451 (long)curproc->p_pid, curproc->p_comm, type);
452 } else if (type != T_NMI && type != T_BPTFLT &&
455 * XXX not quite right, since this may be for a
456 * multiple fault in user mode.
458 MAKEMPSAFE(have_mplock);
459 kprintf("kernel trap %d with interrupts disabled\n",
465 type = frame->tf_trapno;
466 code = frame->tf_err;
468 if (ISPL(frame->tf_cs) == SEL_UPL) {
471 KTR_LOG(kernentry_trap, p->p_pid, lp->lwp_tid,
472 frame->tf_trapno, eva);
476 sticks = (int)td->td_sticks;
477 KASSERT(lp->lwp_md.md_regs == frame,
478 ("Frame mismatch %p %p", lp->lwp_md.md_regs, frame));
481 case T_PRIVINFLT: /* privileged instruction fault */
486 case T_BPTFLT: /* bpt instruction fault */
487 case T_TRCTRAP: /* trace trap */
488 frame->tf_rflags &= ~PSL_T;
490 ucode = (type == T_TRCTRAP ? TRAP_TRACE : TRAP_BRKPT);
493 case T_ARITHTRAP: /* arithmetic trap */
498 case T_ASTFLT: /* Allow process switch */
499 mycpu->gd_cnt.v_soft++;
500 if (mycpu->gd_reqflags & RQF_AST_OWEUPC) {
501 atomic_clear_int(&mycpu->gd_reqflags,
503 addupc_task(p, p->p_prof.pr_addr,
508 case T_PROTFLT: /* general protection fault */
512 case T_STKFLT: /* stack fault */
513 case T_SEGNPFLT: /* segment not present fault */
517 case T_TSSFLT: /* invalid TSS fault */
518 case T_DOUBLEFLT: /* double fault */
524 case T_PAGEFLT: /* page fault */
525 i = trap_pfault(frame, TRUE);
526 if (frame->tf_rip == 0) {
527 kprintf("T_PAGEFLT: Warning %%rip == 0!\n");
529 while (freeze_on_seg_fault)
530 tsleep(p, 0, "freeze", hz * 20);
533 if (i == -1 || i == 0)
545 case T_DIVIDE: /* integer divide fault */
552 MAKEMPSAFE(have_mplock);
553 /* machine/parity/power fail/"kitchen sink" faults */
554 if (isa_nmi(code) == 0) {
557 * NMI can be hooked up to a pushbutton
561 kprintf ("NMI ... going to debugger\n");
562 kdb_trap(type, 0, frame);
566 } else if (panic_on_nmi)
567 panic("NMI indicates hardware failure");
569 #endif /* NISA > 0 */
571 case T_OFLOW: /* integer overflow fault */
576 case T_BOUND: /* bounds check fault */
583 * Virtual kernel intercept - pass the DNA exception
584 * to the virtual kernel if it asked to handle it.
585 * This occurs when the virtual kernel is holding
586 * onto the FP context for a different emulated
587 * process then the one currently running.
589 * We must still call npxdna() since we may have
590 * saved FP state that the virtual kernel needs
591 * to hand over to a different emulated process.
593 if (lp->lwp_vkernel && lp->lwp_vkernel->ve &&
594 (td->td_pcb->pcb_flags & FP_VIRTFP)
601 * The kernel may have switched out the FP unit's
602 * state, causing the user process to take a fault
603 * when it tries to use the FP unit. Restore the
609 ucode = FPE_FPU_NP_TRAP;
612 case T_FPOPFLT: /* FPU operand fetch fault */
617 case T_XMMFLT: /* SIMD floating-point exception */
626 case T_PAGEFLT: /* page fault */
627 trap_pfault(frame, FALSE);
632 * The kernel is apparently using fpu for copying.
633 * XXX this should be fatal unless the kernel has
634 * registered such use.
640 case T_STKFLT: /* stack fault */
643 case T_PROTFLT: /* general protection fault */
644 case T_SEGNPFLT: /* segment not present fault */
646 * Invalid segment selectors and out of bounds
647 * %rip's and %rsp's can be set up in user mode.
648 * This causes a fault in kernel mode when the
649 * kernel tries to return to user mode. We want
650 * to get this fault so that we can fix the
651 * problem here and not have to check all the
652 * selectors and pointers when the user changes
655 if (mycpu->gd_intr_nesting_level == 0) {
656 if (td->td_pcb->pcb_onfault) {
657 frame->tf_rip = (register_t)
658 td->td_pcb->pcb_onfault;
661 if (frame->tf_rip == (long)doreti_iret) {
662 frame->tf_rip = (long)doreti_iret_fault;
670 * PSL_NT can be set in user mode and isn't cleared
671 * automatically when the kernel is entered. This
672 * causes a TSS fault when the kernel attempts to
673 * `iret' because the TSS link is uninitialized. We
674 * want to get this fault so that we can fix the
675 * problem here and not every time the kernel is
678 if (frame->tf_rflags & PSL_NT) {
679 frame->tf_rflags &= ~PSL_NT;
684 case T_TRCTRAP: /* trace trap */
686 if (frame->tf_rip == (int)IDTVEC(syscall)) {
688 * We've just entered system mode via the
689 * syscall lcall. Continue single stepping
690 * silently until the syscall handler has
695 if (frame->tf_rip == (int)IDTVEC(syscall) + 1) {
697 * The syscall handler has now saved the
698 * flags. Stop single stepping it.
700 frame->tf_rflags &= ~PSL_T;
706 * Ignore debug register trace traps due to
707 * accesses in the user's address space, which
708 * can happen under several conditions such as
709 * if a user sets a watchpoint on a buffer and
710 * then passes that buffer to a system call.
711 * We still want to get TRCTRAPS for addresses
712 * in kernel space because that is useful when
713 * debugging the kernel.
716 if (user_dbreg_trap()) {
718 * Reset breakpoint bits because the
721 /* XXX check upper bits here */
722 load_dr6(rdr6() & 0xfffffff0);
727 * FALLTHROUGH (TRCTRAP kernel mode, kernel address)
731 * If DDB is enabled, let it handle the debugger trap.
732 * Otherwise, debugger traps "can't happen".
736 MAKEMPSAFE(have_mplock);
737 if (kdb_trap(type, 0, frame))
744 MAKEMPSAFE(have_mplock);
745 /* machine/parity/power fail/"kitchen sink" faults */
746 if (isa_nmi(code) == 0) {
749 * NMI can be hooked up to a pushbutton
753 kprintf ("NMI ... going to debugger\n");
754 kdb_trap(type, 0, frame);
758 } else if (panic_on_nmi == 0)
761 #endif /* NISA > 0 */
763 MAKEMPSAFE(have_mplock);
764 trap_fatal(frame, 0);
769 * Virtual kernel intercept - if the fault is directly related to a
770 * VM context managed by a virtual kernel then let the virtual kernel
773 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) {
774 vkernel_trap(lp, frame);
778 /* Translate fault for emulators (e.g. Linux) */
779 if (*p->p_sysent->sv_transtrap)
780 i = (*p->p_sysent->sv_transtrap)(i, type);
782 MAKEMPSAFE(have_mplock);
783 trapsignal(lp, i, ucode);
786 if (type <= MAX_TRAP_MSG) {
787 uprintf("fatal process exception: %s",
789 if ((type == T_PAGEFLT) || (type == T_PROTFLT))
790 uprintf(", fault VA = 0x%lx", frame->tf_addr);
796 userret(lp, frame, sticks);
803 if (p != NULL && lp != NULL)
804 KTR_LOG(kernentry_trap_ret, p->p_pid, lp->lwp_tid);
806 KASSERT(crit_count == td->td_critcount,
807 ("trap: critical section count mismatch! %d/%d",
808 crit_count, td->td_pri));
809 KASSERT(curstop == td->td_toks_stop,
810 ("trap: extra tokens held after trap! %ld/%ld",
811 curstop - &td->td_toks_base,
812 td->td_toks_stop - &td->td_toks_base));
817 trap_pfault(struct trapframe *frame, int usermode)
820 struct vmspace *vm = NULL;
825 thread_t td = curthread;
826 struct lwp *lp = td->td_lwp;
829 va = trunc_page(frame->tf_addr);
830 if (va >= VM_MIN_KERNEL_ADDRESS) {
832 * Don't allow user-mode faults in kernel address space.
843 * This is a fault on non-kernel virtual memory.
844 * vm is initialized above to NULL. If curproc is NULL
845 * or curproc->p_vmspace is NULL the fault is fatal.
848 vm = lp->lwp_vmspace;
857 * Debugging, try to catch kernel faults on the user address space when not inside
858 * on onfault (e.g. copyin/copyout) routine.
860 if (usermode == 0 && (td->td_pcb == NULL || td->td_pcb->pcb_onfault == NULL)) {
862 if (freeze_on_seg_fault) {
863 kprintf("trap_pfault: user address fault from kernel mode "
864 "%016lx\n", (long)frame->tf_addr);
865 while (freeze_on_seg_fault)
866 tsleep(&freeze_on_seg_fault, 0, "frzseg", hz * 20);
874 * PGEX_I is defined only if the execute disable bit capability is
875 * supported and enabled.
877 if (frame->tf_err & PGEX_W)
878 ftype = VM_PROT_WRITE;
880 else if ((frame->tf_err & PGEX_I) && pg_nx != 0)
881 ftype = VM_PROT_EXECUTE;
884 ftype = VM_PROT_READ;
886 if (map != &kernel_map) {
888 * Keep swapout from messing with us during this
898 fault_flags |= VM_FAULT_BURST;
899 if (ftype & VM_PROT_WRITE)
900 fault_flags |= VM_FAULT_DIRTY;
902 fault_flags |= VM_FAULT_NORMAL;
903 rv = vm_fault(map, va, ftype, fault_flags);
908 * Don't have to worry about process locking or stacks in the
911 fault_flags = VM_FAULT_NORMAL;
912 rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL);
914 if (rv == KERN_SUCCESS)
918 if (td->td_gd->gd_intr_nesting_level == 0 &&
919 td->td_pcb->pcb_onfault) {
920 frame->tf_rip = (register_t)td->td_pcb->pcb_onfault;
923 trap_fatal(frame, frame->tf_addr);
928 * NOTE: on x86_64 we have a tf_addr field in the trapframe, no
929 * kludge is needed to pass the fault address to signal handlers.
932 if (td->td_lwp->lwp_vkernel == NULL) {
934 if (bootverbose || freeze_on_seg_fault || ddb_on_seg_fault) {
938 kprintf("seg-fault ft=%04x ff=%04x addr=%p rip=%p "
939 "pid=%d cpu=%d p_comm=%s\n",
941 (void *)frame->tf_addr,
942 (void *)frame->tf_rip,
943 p->p_pid, mycpu->gd_cpuid, p->p_comm);
946 while (freeze_on_seg_fault) {
947 tsleep(p, 0, "freeze", hz * 20);
949 if (ddb_on_seg_fault)
950 Debugger("ddb_on_seg_fault");
954 return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV);
958 trap_fatal(struct trapframe *frame, vm_offset_t eva)
963 struct soft_segment_descriptor softseg;
966 code = frame->tf_err;
967 type = frame->tf_trapno;
968 sdtossd(&gdt[IDXSEL(frame->tf_cs & 0xffff)], &softseg);
970 if (type <= MAX_TRAP_MSG)
971 msg = trap_msg[type];
974 kprintf("\n\nFatal trap %d: %s while in %s mode\n", type, msg,
975 ISPL(frame->tf_cs) == SEL_UPL ? "user" : "kernel");
977 /* three separate prints in case of a trap on an unmapped page */
978 kprintf("cpuid = %d; ", mycpu->gd_cpuid);
979 kprintf("lapic->id = %08x\n", lapic->id);
981 if (type == T_PAGEFLT) {
982 kprintf("fault virtual address = 0x%lx\n", eva);
983 kprintf("fault code = %s %s %s, %s\n",
984 code & PGEX_U ? "user" : "supervisor",
985 code & PGEX_W ? "write" : "read",
986 code & PGEX_I ? "instruction" : "data",
987 code & PGEX_P ? "protection violation" : "page not present");
989 kprintf("instruction pointer = 0x%lx:0x%lx\n",
990 frame->tf_cs & 0xffff, frame->tf_rip);
991 if (ISPL(frame->tf_cs) == SEL_UPL) {
992 ss = frame->tf_ss & 0xffff;
995 ss = GSEL(GDATA_SEL, SEL_KPL);
996 rsp = (long)&frame->tf_rsp;
998 kprintf("stack pointer = 0x%x:0x%lx\n", ss, rsp);
999 kprintf("frame pointer = 0x%x:0x%lx\n", ss, frame->tf_rbp);
1000 kprintf("code segment = base 0x%lx, limit 0x%lx, type 0x%x\n",
1001 softseg.ssd_base, softseg.ssd_limit, softseg.ssd_type);
1002 kprintf(" = DPL %d, pres %d, long %d, def32 %d, gran %d\n",
1003 softseg.ssd_dpl, softseg.ssd_p, softseg.ssd_long, softseg.ssd_def32,
1005 kprintf("processor eflags = ");
1006 if (frame->tf_rflags & PSL_T)
1007 kprintf("trace trap, ");
1008 if (frame->tf_rflags & PSL_I)
1009 kprintf("interrupt enabled, ");
1010 if (frame->tf_rflags & PSL_NT)
1011 kprintf("nested task, ");
1012 if (frame->tf_rflags & PSL_RF)
1013 kprintf("resume, ");
1014 kprintf("IOPL = %ld\n", (frame->tf_rflags & PSL_IOPL) >> 12);
1015 kprintf("current process = ");
1018 (u_long)curproc->p_pid);
1022 kprintf("current thread = pri %d ", curthread->td_pri);
1023 if (curthread->td_critcount)
1028 if ((debugger_on_panic || db_active) && kdb_trap(type, code, frame))
1031 kprintf("trap number = %d\n", type);
1032 if (type <= MAX_TRAP_MSG)
1033 panic("%s", trap_msg[type]);
1035 panic("unknown/reserved trap");
1039 * Double fault handler. Called when a fault occurs while writing
1040 * a frame for a trap/exception onto the stack. This usually occurs
1041 * when the stack overflows (such is the case with infinite recursion,
1046 in_kstack_guard(register_t rptr)
1048 thread_t td = curthread;
1050 if ((char *)rptr >= td->td_kstack &&
1051 (char *)rptr < td->td_kstack + PAGE_SIZE) {
1058 dblfault_handler(struct trapframe *frame)
1060 thread_t td = curthread;
1062 if (in_kstack_guard(frame->tf_rsp) || in_kstack_guard(frame->tf_rbp)) {
1063 kprintf("DOUBLE FAULT - KERNEL STACK GUARD HIT!\n");
1064 if (in_kstack_guard(frame->tf_rsp))
1065 frame->tf_rsp = (register_t)(td->td_kstack + PAGE_SIZE);
1066 if (in_kstack_guard(frame->tf_rbp))
1067 frame->tf_rbp = (register_t)(td->td_kstack + PAGE_SIZE);
1069 kprintf("DOUBLE FAULT\n");
1071 kprintf("\nFatal double fault\n");
1072 kprintf("rip = 0x%lx\n", frame->tf_rip);
1073 kprintf("rsp = 0x%lx\n", frame->tf_rsp);
1074 kprintf("rbp = 0x%lx\n", frame->tf_rbp);
1076 /* three separate prints in case of a trap on an unmapped page */
1077 kprintf("cpuid = %d; ", mycpu->gd_cpuid);
1078 kprintf("lapic->id = %08x\n", lapic->id);
1080 panic("double fault");
1084 * syscall2 - MP aware system call request C handler
1086 * A system call is essentially treated as a trap except that the
1087 * MP lock is not held on entry or return. We are responsible for
1088 * obtaining the MP lock if necessary and for handling ASTs
1089 * (e.g. a task switch) prior to return.
1094 syscall2(struct trapframe *frame)
1096 struct thread *td = curthread;
1097 struct proc *p = td->td_proc;
1098 struct lwp *lp = td->td_lwp;
1100 struct sysent *callp;
1101 register_t orig_tf_rflags;
1106 int crit_count = td->td_critcount;
1109 int have_mplock = 0;
1114 union sysunion args;
1115 register_t *argsdst;
1117 mycpu->gd_cnt.v_syscall++;
1120 if (ISPL(frame->tf_cs) != SEL_UPL) {
1127 KTR_LOG(kernentry_syscall, p->p_pid, lp->lwp_tid,
1130 userenter(td, p); /* lazy raise our priority */
1137 sticks = (int)td->td_sticks;
1138 orig_tf_rflags = frame->tf_rflags;
1141 * Virtual kernel intercept - if a VM context managed by a virtual
1142 * kernel issues a system call the virtual kernel handles it, not us.
1143 * Restore the virtual kernel context and return from its system
1144 * call. The current frame is copied out to the virtual kernel.
1146 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) {
1147 vkernel_trap(lp, frame);
1148 error = EJUSTRETURN;
1153 * Get the system call parameters and account for time
1155 KASSERT(lp->lwp_md.md_regs == frame,
1156 ("Frame mismatch %p %p", lp->lwp_md.md_regs, frame));
1157 params = (caddr_t)frame->tf_rsp + sizeof(register_t);
1158 code = frame->tf_rax;
1160 if (p->p_sysent->sv_prepsyscall) {
1161 (*p->p_sysent->sv_prepsyscall)(
1162 frame, (int *)(&args.nosys.sysmsg + 1),
1165 if (code == SYS_syscall || code == SYS___syscall) {
1166 code = frame->tf_rdi;
1172 if (p->p_sysent->sv_mask)
1173 code &= p->p_sysent->sv_mask;
1175 if (code >= p->p_sysent->sv_size)
1176 callp = &p->p_sysent->sv_table[0];
1178 callp = &p->p_sysent->sv_table[code];
1180 narg = callp->sy_narg & SYF_ARGMASK;
1183 * On x86_64 we get up to six arguments in registers. The rest are
1184 * on the stack. The first six members of 'struct trapframe' happen
1185 * to be the registers used to pass arguments, in exactly the right
1188 argp = &frame->tf_rdi;
1190 argsdst = (register_t *)(&args.nosys.sysmsg + 1);
1192 * JG can we overflow the space pointed to by 'argsdst'
1193 * either with 'bcopy' or with 'copyin'?
1195 bcopy(argp, argsdst, sizeof(register_t) * regcnt);
1197 * copyin is MP aware, but the tracing code is not
1199 if (narg > regcnt) {
1200 KASSERT(params != NULL, ("copyin args with no params!"));
1201 error = copyin(params, &argsdst[regcnt],
1202 (narg - regcnt) * sizeof(register_t));
1205 if (KTRPOINT(td, KTR_SYSCALL)) {
1206 MAKEMPSAFE(have_mplock);
1208 ktrsyscall(lp, code, narg,
1209 (void *)(&args.nosys.sysmsg + 1));
1217 if (KTRPOINT(td, KTR_SYSCALL)) {
1218 MAKEMPSAFE(have_mplock);
1219 ktrsyscall(lp, code, narg, (void *)(&args.nosys.sysmsg + 1));
1224 * Default return value is 0 (will be copied to %rax). Double-value
1225 * returns use %rax and %rdx. %rdx is left unchanged for system
1226 * calls which return only one result.
1228 args.sysmsg_fds[0] = 0;
1229 args.sysmsg_fds[1] = frame->tf_rdx;
1232 * The syscall might manipulate the trap frame. If it does it
1233 * will probably return EJUSTRETURN.
1235 args.sysmsg_frame = frame;
1237 STOPEVENT(p, S_SCE, narg); /* MP aware */
1240 * NOTE: All system calls run MPSAFE now. The system call itself
1241 * is responsible for getting the MP lock.
1243 #ifdef SYSCALL_DEBUG
1244 uint64_t tscval = rdtsc();
1246 error = (*callp->sy_call)(&args);
1247 #ifdef SYSCALL_DEBUG
1248 tscval = rdtsc() - tscval;
1249 tscval = tscval * 1000000 / tsc_frequency;
1250 if (SysCallsWorstCase[code] < tscval)
1251 SysCallsWorstCase[code] = tscval;
1256 * MP SAFE (we may or may not have the MP lock at this point)
1258 //kprintf("SYSMSG %d ", error);
1262 * Reinitialize proc pointer `p' as it may be different
1263 * if this is a child returning from fork syscall.
1266 lp = curthread->td_lwp;
1267 frame->tf_rax = args.sysmsg_fds[0];
1268 frame->tf_rdx = args.sysmsg_fds[1];
1269 frame->tf_rflags &= ~PSL_C;
1273 * Reconstruct pc, we know that 'syscall' is 2 bytes.
1274 * We have to do a full context restore so that %r10
1275 * (which was holding the value of %rcx) is restored for
1276 * the next iteration.
1278 if (frame->tf_err != 0 && frame->tf_err != 2)
1279 kprintf("lp %s:%d frame->tf_err is weird %ld\n",
1280 td->td_comm, lp->lwp_proc->p_pid, frame->tf_err);
1281 frame->tf_rip -= frame->tf_err;
1282 frame->tf_r10 = frame->tf_rcx;
1287 panic("Unexpected EASYNC return value (for now)");
1290 if (p->p_sysent->sv_errsize) {
1291 if (error >= p->p_sysent->sv_errsize)
1292 error = -1; /* XXX */
1294 error = p->p_sysent->sv_errtbl[error];
1296 frame->tf_rax = error;
1297 frame->tf_rflags |= PSL_C;
1302 * Traced syscall. trapsignal() is not MP aware.
1304 if (orig_tf_rflags & PSL_T) {
1305 MAKEMPSAFE(have_mplock);
1306 frame->tf_rflags &= ~PSL_T;
1307 trapsignal(lp, SIGTRAP, TRAP_TRACE);
1311 * Handle reschedule and other end-of-syscall issues
1313 userret(lp, frame, sticks);
1316 if (KTRPOINT(td, KTR_SYSRET)) {
1317 MAKEMPSAFE(have_mplock);
1318 ktrsysret(lp, code, error, args.sysmsg_result);
1323 * This works because errno is findable through the
1324 * register set. If we ever support an emulation where this
1325 * is not the case, this code will need to be revisited.
1327 STOPEVENT(p, S_SCX, code);
1332 * Release the MP lock if we had to get it
1337 KTR_LOG(kernentry_syscall_ret, p->p_pid, lp->lwp_tid, error);
1339 KASSERT(crit_count == td->td_critcount,
1340 ("syscall: critical section count mismatch! %d/%d",
1341 crit_count, td->td_pri));
1342 KASSERT(&td->td_toks_base == td->td_toks_stop,
1343 ("syscall: extra tokens held after trap! %ld",
1344 td->td_toks_stop - &td->td_toks_base));
1349 * NOTE: mplock not held at any point
1352 fork_return(struct lwp *lp, struct trapframe *frame)
1354 frame->tf_rax = 0; /* Child returns zero */
1355 frame->tf_rflags &= ~PSL_C; /* success */
1358 generic_lwp_return(lp, frame);
1359 KTR_LOG(kernentry_fork_ret, lp->lwp_proc->p_pid, lp->lwp_tid);
1363 * Simplified back end of syscall(), used when returning from fork()
1364 * directly into user mode.
1366 * This code will return back into the fork trampoline code which then
1369 * NOTE: The mplock is not held at any point.
1372 generic_lwp_return(struct lwp *lp, struct trapframe *frame)
1374 struct proc *p = lp->lwp_proc;
1377 * Newly forked processes are given a kernel priority. We have to
1378 * adjust the priority to a normal user priority and fake entry
1379 * into the kernel (call userenter()) to install a passive release
1380 * function just in case userret() decides to stop the process. This
1381 * can occur when ^Z races a fork. If we do not install the passive
1382 * release function the current process designation will not be
1383 * released when the thread goes to sleep.
1385 lwkt_setpri_self(TDPRI_USER_NORM);
1386 userenter(lp->lwp_thread, p);
1387 userret(lp, frame, 0);
1389 if (KTRPOINT(lp->lwp_thread, KTR_SYSRET))
1390 ktrsysret(lp, SYS_fork, 0, 0);
1392 lp->lwp_flags |= LWP_PASSIVE_ACQ;
1394 lp->lwp_flags &= ~LWP_PASSIVE_ACQ;
1398 * If PGEX_FPFAULT is set then set FP_VIRTFP in the PCB to force a T_DNA
1399 * fault (which is then passed back to the virtual kernel) if an attempt is
1400 * made to use the FP unit.
1402 * XXX this is a fairly big hack.
1405 set_vkernel_fp(struct trapframe *frame)
1407 struct thread *td = curthread;
1409 if (frame->tf_xflags & PGEX_FPFAULT) {
1410 td->td_pcb->pcb_flags |= FP_VIRTFP;
1411 if (mdcpu->gd_npxthread == td)
1414 td->td_pcb->pcb_flags &= ~FP_VIRTFP;
1419 * Called from vkernel_trap() to fixup the vkernel's syscall
1420 * frame for vmspace_ctl() return.
1423 cpu_vkernel_trap(struct trapframe *frame, int error)
1425 frame->tf_rax = error;
1427 frame->tf_rflags |= PSL_C;
1429 frame->tf_rflags &= ~PSL_C;