2 * Copyright (C) 1994, David Greenman
3 * Copyright (c) 1990, 1993
4 * The Regents of the University of California. All rights reserved.
6 * This code is derived from software contributed to Berkeley by
7 * the University of Utah, and William Jolitz.
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 * 3. All advertising materials mentioning features or use of this software
18 * must display the following acknowledgement:
19 * This product includes software developed by the University of
20 * California, Berkeley and its contributors.
21 * 4. Neither the name of the University nor the names of its contributors
22 * may be used to endorse or promote products derived from this software
23 * without specific prior written permission.
25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
28 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
37 * from: @(#)trap.c 7.4 (Berkeley) 5/13/91
38 * $FreeBSD: src/sys/i386/i386/trap.c,v 1.147.2.11 2003/02/27 19:09:59 luoqi Exp $
39 * $DragonFly: src/sys/platform/vkernel/i386/trap.c,v 1.35 2008/09/09 04:06:19 dillon Exp $
43 * 386 Trap and System call handling
50 #include "opt_ktrace.h"
52 #include <sys/param.h>
53 #include <sys/systm.h>
55 #include <sys/pioctl.h>
56 #include <sys/kernel.h>
57 #include <sys/resourcevar.h>
58 #include <sys/signalvar.h>
59 #include <sys/signal2.h>
60 #include <sys/syscall.h>
61 #include <sys/sysctl.h>
62 #include <sys/sysent.h>
64 #include <sys/vmmeter.h>
65 #include <sys/malloc.h>
67 #include <sys/ktrace.h>
70 #include <sys/upcall.h>
71 #include <sys/vkernel.h>
72 #include <sys/sysproto.h>
73 #include <sys/sysunion.h>
74 #include <sys/vmspace.h>
77 #include <vm/vm_param.h>
80 #include <vm/vm_kern.h>
81 #include <vm/vm_map.h>
82 #include <vm/vm_page.h>
83 #include <vm/vm_extern.h>
85 #include <machine/cpu.h>
86 #include <machine/md_var.h>
87 #include <machine/pcb.h>
88 #include <machine/smp.h>
89 #include <machine/tss.h>
90 #include <machine/globaldata.h>
92 #include <machine/vm86.h>
96 #include <sys/msgport2.h>
97 #include <sys/thread2.h>
98 #include <sys/mplock2.h>
102 #define MAKEMPSAFE(have_mplock) \
103 if (have_mplock == 0) { \
110 #define MAKEMPSAFE(have_mplock)
114 int (*pmath_emulate) (struct trapframe *);
116 static int trap_pfault (struct trapframe *, int, vm_offset_t);
117 static void trap_fatal (struct trapframe *, int, vm_offset_t);
118 void dblfault_handler (void);
121 extern inthand_t IDTVEC(syscall);
124 #define MAX_TRAP_MSG 28
125 static char *trap_msg[] = {
127 "privileged instruction fault", /* 1 T_PRIVINFLT */
129 "breakpoint instruction fault", /* 3 T_BPTFLT */
132 "arithmetic trap", /* 6 T_ARITHTRAP */
133 "system forced exception", /* 7 T_ASTFLT */
135 "general protection fault", /* 9 T_PROTFLT */
136 "trace trap", /* 10 T_TRCTRAP */
138 "page fault", /* 12 T_PAGEFLT */
140 "alignment fault", /* 14 T_ALIGNFLT */
144 "integer divide fault", /* 18 T_DIVIDE */
145 "non-maskable interrupt trap", /* 19 T_NMI */
146 "overflow trap", /* 20 T_OFLOW */
147 "FPU bounds check fault", /* 21 T_BOUND */
148 "FPU device not available", /* 22 T_DNA */
149 "double fault", /* 23 T_DOUBLEFLT */
150 "FPU operand fetch fault", /* 24 T_FPOPFLT */
151 "invalid TSS fault", /* 25 T_TSSFLT */
152 "segment not present fault", /* 26 T_SEGNPFLT */
153 "stack fault", /* 27 T_STKFLT */
154 "machine check trap", /* 28 T_MCHK */
158 static int ddb_on_nmi = 1;
159 SYSCTL_INT(_machdep, OID_AUTO, ddb_on_nmi, CTLFLAG_RW,
160 &ddb_on_nmi, 0, "Go to DDB on NMI");
162 static int panic_on_nmi = 1;
163 SYSCTL_INT(_machdep, OID_AUTO, panic_on_nmi, CTLFLAG_RW,
164 &panic_on_nmi, 0, "Panic on NMI");
165 static int fast_release;
166 SYSCTL_INT(_machdep, OID_AUTO, fast_release, CTLFLAG_RW,
167 &fast_release, 0, "Passive Release was optimal");
168 static int slow_release;
169 SYSCTL_INT(_machdep, OID_AUTO, slow_release, CTLFLAG_RW,
170 &slow_release, 0, "Passive Release was nonoptimal");
172 static int syscall_mpsafe = 1;
173 SYSCTL_INT(_kern, OID_AUTO, syscall_mpsafe, CTLFLAG_RW,
174 &syscall_mpsafe, 0, "Allow MPSAFE marked syscalls to run without BGL");
175 TUNABLE_INT("kern.syscall_mpsafe", &syscall_mpsafe);
176 static int trap_mpsafe = 1;
177 SYSCTL_INT(_kern, OID_AUTO, trap_mpsafe, CTLFLAG_RW,
178 &trap_mpsafe, 0, "Allow traps to mostly run without the BGL");
179 TUNABLE_INT("kern.trap_mpsafe", &trap_mpsafe);
182 MALLOC_DEFINE(M_SYSMSG, "sysmsg", "sysmsg structure");
183 extern int max_sysmsg;
186 * Passively intercepts the thread switch function to increase
187 * the thread priority from a user priority to a kernel priority, reducing
188 * syscall and trap overhead for the case where no switch occurs.
190 * Synchronizes td_ucred with p_ucred. This is used by system calls,
191 * signal handling, faults, AST traps, and anything else that enters the
192 * kernel from userland and provides the kernel with a stable read-only
193 * copy of the process ucred.
196 userenter(struct thread *curtd, struct proc *curp)
201 curtd->td_release = lwkt_passive_release;
203 if (curtd->td_ucred != curp->p_ucred) {
204 ncred = crhold(curp->p_ucred);
205 ocred = curtd->td_ucred;
206 curtd->td_ucred = ncred;
213 * Handle signals, upcalls, profiling, and other AST's and/or tasks that
214 * must be completed before we can return to or try to return to userland.
216 * Note that td_sticks is a 64 bit quantity, but there's no point doing 64
217 * arithmatic on the delta calculation so the absolute tick values are
218 * truncated to an integer.
221 userret(struct lwp *lp, struct trapframe *frame, int sticks)
223 struct proc *p = lp->lwp_proc;
227 * Charge system time if profiling. Note: times are in microseconds.
228 * This may do a copyout and block, so do it first even though it
229 * means some system time will be charged as user time.
231 if (p->p_flag & P_PROFIL) {
232 addupc_task(p, frame->tf_eip,
233 (u_int)((int)lp->lwp_thread->td_sticks - sticks));
238 * If the jungle wants us dead, so be it.
240 if (lp->lwp_flag & LWP_WEXIT) {
243 rel_mplock(); /* NOT REACHED */
247 * Block here if we are in a stopped state.
249 if (p->p_stat == SSTOP) {
257 * Post any pending upcalls
259 if (p->p_flag & P_UPCALLPEND) {
261 p->p_flag &= ~P_UPCALLPEND;
268 * Post any pending signals
270 if ((sig = CURSIG_TRACE(lp)) != 0) {
278 * block here if we are swapped out, but still process signals
279 * (such as SIGKILL). proc0 (the swapin scheduler) is already
280 * aware of our situation, we do not have to wake it up.
282 if (p->p_flag & P_SWAPPEDOUT) {
284 p->p_flag |= P_SWAPWAIT;
286 if (p->p_flag & P_SWAPWAIT)
287 tsleep(p, PCATCH, "SWOUT", 0);
288 p->p_flag &= ~P_SWAPWAIT;
294 * Make sure postsig() handled request to restore old signal mask after
295 * running signal handler.
297 KKASSERT((lp->lwp_flag & LWP_OLDMASK) == 0);
301 * Cleanup from userenter and any passive release that might have occured.
302 * We must reclaim the current-process designation before we can return
303 * to usermode. We also handle both LWKT and USER reschedule requests.
306 userexit(struct lwp *lp)
308 struct thread *td = lp->lwp_thread;
309 /* globaldata_t gd = td->td_gd; */
312 * Handle stop requests at kernel priority. Any requests queued
313 * after this loop will generate another AST.
315 while (lp->lwp_proc->p_stat == SSTOP) {
322 * Reduce our priority in preparation for a return to userland. If
323 * our passive release function was still in place, our priority was
324 * never raised and does not need to be reduced.
326 lwkt_passive_recover(td);
329 * Become the current user scheduled process if we aren't already,
330 * and deal with reschedule requests and other factors.
332 lp->lwp_proc->p_usched->acquire_curproc(lp);
333 /* WARNING: we may have migrated cpu's */
334 /* gd = td->td_gd; */
337 #if !defined(KTR_KERNENTRY)
338 #define KTR_KERNENTRY KTR_ALL
340 KTR_INFO_MASTER(kernentry);
341 KTR_INFO(KTR_KERNENTRY, kernentry, trap, 0, "pid=%d, tid=%d, trapno=%d, eva=%p",
342 sizeof(int) + sizeof(int) + sizeof(int) + sizeof(vm_offset_t));
343 KTR_INFO(KTR_KERNENTRY, kernentry, trap_ret, 0, "pid=%d, tid=%d",
344 sizeof(int) + sizeof(int));
345 KTR_INFO(KTR_KERNENTRY, kernentry, syscall, 0, "pid=%d, tid=%d, call=%d",
346 sizeof(int) + sizeof(int) + sizeof(int));
347 KTR_INFO(KTR_KERNENTRY, kernentry, syscall_ret, 0, "pid=%d, tid=%d, err=%d",
348 sizeof(int) + sizeof(int) + sizeof(int));
349 KTR_INFO(KTR_KERNENTRY, kernentry, fork_ret, 0, "pid=%d, tid=%d",
350 sizeof(int) + sizeof(int));
353 * Exception, fault, and trap interface to the kernel.
354 * This common code is called from assembly language IDT gate entry
355 * routines that prepare a suitable stack frame, and restore this
356 * frame after the exception has been processed.
358 * This function is also called from doreti in an interlock to handle ASTs.
359 * For example: hardwareint->INTROUTINE->(set ast)->doreti->trap
361 * NOTE! We have to retrieve the fault address prior to obtaining the
362 * MP lock because get_mplock() may switch out. YYY cr2 really ought
363 * to be retrieved by the assembly code, not here.
365 * XXX gd_trap_nesting_level currently prevents lwkt_switch() from panicing
366 * if an attempt is made to switch from a fast interrupt or IPI. This is
367 * necessary to properly take fatal kernel traps on SMP machines if
368 * get_mplock() has to block.
372 user_trap(struct trapframe *frame)
374 struct globaldata *gd = mycpu;
375 struct thread *td = gd->gd_curthread;
376 struct lwp *lp = td->td_lwp;
379 int i = 0, ucode = 0, type, code;
384 int crit_count = td->td_critcount;
391 * This is a bad kludge to avoid changing the various trapframe
392 * structures. Because we are enabled as a virtual kernel,
393 * the original tf_err field will be passed to us shifted 16
394 * over in the tf_trapno field for T_PAGEFLT.
396 if (frame->tf_trapno == T_PAGEFLT)
401 kprintf("USER_TRAP AT %08x xflags %d trapno %d eva %08x\n",
402 frame->tf_eip, frame->tf_xflags, frame->tf_trapno, eva);
406 * Everything coming from user mode runs through user_trap,
407 * including system calls.
409 if (frame->tf_trapno == T_SYSCALL80) {
414 KTR_LOG(kernentry_trap, lp->lwp_proc->p_pid, lp->lwp_tid,
415 frame->tf_trapno, eva);
419 eva = (frame->tf_trapno == T_PAGEFLT ? rcr2() : 0);
420 ++gd->gd_trap_nesting_level;
421 MAKEMPSAFE(have_mplock);
422 trap_fatal(frame, TRUE, eva);
423 --gd->gd_trap_nesting_level;
428 ++gd->gd_trap_nesting_level;
430 if (trap_mpsafe == 0)
431 MAKEMPSAFE(have_mplock);
434 --gd->gd_trap_nesting_level;
436 #if defined(I586_CPU) && !defined(NO_F00F_HACK)
439 type = frame->tf_trapno;
440 code = frame->tf_err;
444 sticks = (int)td->td_sticks;
445 lp->lwp_md.md_regs = frame;
448 case T_PRIVINFLT: /* privileged instruction fault */
453 case T_BPTFLT: /* bpt instruction fault */
454 case T_TRCTRAP: /* trace trap */
455 frame->tf_eflags &= ~PSL_T;
460 case T_ARITHTRAP: /* arithmetic trap */
465 case T_ASTFLT: /* Allow process switch */
466 mycpu->gd_cnt.v_soft++;
467 if (mycpu->gd_reqflags & RQF_AST_OWEUPC) {
468 atomic_clear_int_nonlocked(&mycpu->gd_reqflags,
470 addupc_task(p, p->p_prof.pr_addr,
476 * The following two traps can happen in
477 * vm86 mode, and, if so, we want to handle
480 case T_PROTFLT: /* general protection fault */
481 case T_STKFLT: /* stack fault */
483 if (frame->tf_eflags & PSL_VM) {
484 i = vm86_emulate((struct vm86frame *)frame);
491 ucode = (type == T_PROTFLT) ? BUS_OBJERR : BUS_ADRERR;
493 case T_SEGNPFLT: /* segment not present fault */
497 case T_TSSFLT: /* invalid TSS fault */
498 case T_DOUBLEFLT: /* double fault */
503 ucode = code + BUS_SEGM_FAULT ; /* XXX: ???*/
509 case T_PAGEFLT: /* page fault */
510 MAKEMPSAFE(have_mplock);
511 i = trap_pfault(frame, TRUE, eva);
514 #if defined(I586_CPU) && !defined(NO_F00F_HACK)
530 case T_DIVIDE: /* integer divide fault */
537 MAKEMPSAFE(have_mplock);
538 /* machine/parity/power fail/"kitchen sink" faults */
539 if (isa_nmi(code) == 0) {
542 * NMI can be hooked up to a pushbutton
546 kprintf ("NMI ... going to debugger\n");
547 kdb_trap (type, 0, frame);
551 } else if (panic_on_nmi)
552 panic("NMI indicates hardware failure");
554 #endif /* NISA > 0 */
556 case T_OFLOW: /* integer overflow fault */
561 case T_BOUND: /* bounds check fault */
568 * Virtual kernel intercept - pass the DNA exception
569 * to the (emulated) virtual kernel if it asked to handle
570 * it. This occurs when the virtual kernel is holding
571 * onto the FP context for a different emulated
572 * process then the one currently running.
574 * We must still call npxdna() since we may have
575 * saved FP state that the (emulated) virtual kernel
576 * needs to hand over to a different emulated process.
578 if (lp->lwp_vkernel && lp->lwp_vkernel->ve &&
579 (td->td_pcb->pcb_flags & FP_VIRTFP)
586 * The kernel may have switched out the FP unit's
587 * state, causing the user process to take a fault
588 * when it tries to use the FP unit. Restore the
594 if (!pmath_emulate) {
596 ucode = FPE_FPU_NP_TRAP;
599 i = (*pmath_emulate)(frame);
601 if (!(frame->tf_eflags & PSL_T))
603 frame->tf_eflags &= ~PSL_T;
606 /* else ucode = emulator_only_knows() XXX */
609 case T_FPOPFLT: /* FPU operand fetch fault */
614 case T_XMMFLT: /* SIMD floating-point exception */
621 * Virtual kernel intercept - if the fault is directly related to a
622 * VM context managed by a virtual kernel then let the virtual kernel
625 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) {
626 vkernel_trap(lp, frame);
631 * Translate fault for emulators (e.g. Linux)
633 if (*p->p_sysent->sv_transtrap)
634 i = (*p->p_sysent->sv_transtrap)(i, type);
636 MAKEMPSAFE(have_mplock);
637 trapsignal(lp, i, ucode);
640 if (type <= MAX_TRAP_MSG) {
641 uprintf("fatal process exception: %s",
643 if ((type == T_PAGEFLT) || (type == T_PROTFLT))
644 uprintf(", fault VA = 0x%lx", (u_long)eva);
651 KASSERT(td->td_mpcount == have_mplock, ("badmpcount trap/end from %p", (void *)frame->tf_eip));
653 userret(lp, frame, sticks);
660 KTR_LOG(kernentry_trap_ret, lp->lwp_proc->p_pid, lp->lwp_tid);
662 KASSERT(crit_count == td->td_critcount,
663 ("syscall: critical section count mismatch! %d/%d",
664 crit_count, td->td_pri));
669 kern_trap(struct trapframe *frame)
671 struct globaldata *gd = mycpu;
672 struct thread *td = gd->gd_curthread;
675 int i = 0, ucode = 0, type, code;
680 int crit_count = td->td_critcount;
687 if (frame->tf_trapno == T_PAGEFLT)
694 ++gd->gd_trap_nesting_level;
695 MAKEMPSAFE(have_mplock);
696 trap_fatal(frame, FALSE, eva);
697 --gd->gd_trap_nesting_level;
702 ++gd->gd_trap_nesting_level;
705 if (trap_mpsafe == 0)
706 MAKEMPSAFE(have_mplock);
709 --gd->gd_trap_nesting_level;
711 type = frame->tf_trapno;
712 code = frame->tf_err;
720 case T_PAGEFLT: /* page fault */
721 MAKEMPSAFE(have_mplock);
722 trap_pfault(frame, FALSE, eva);
728 * The kernel may be using npx for copying or other
731 panic("kernel NPX should not happen");
737 case T_PROTFLT: /* general protection fault */
738 case T_SEGNPFLT: /* segment not present fault */
740 * Invalid segment selectors and out of bounds
741 * %eip's and %esp's can be set up in user mode.
742 * This causes a fault in kernel mode when the
743 * kernel tries to return to user mode. We want
744 * to get this fault so that we can fix the
745 * problem here and not have to check all the
746 * selectors and pointers when the user changes
749 if (mycpu->gd_intr_nesting_level == 0) {
750 if (td->td_pcb->pcb_onfault) {
752 (register_t)td->td_pcb->pcb_onfault;
760 * PSL_NT can be set in user mode and isn't cleared
761 * automatically when the kernel is entered. This
762 * causes a TSS fault when the kernel attempts to
763 * `iret' because the TSS link is uninitialized. We
764 * want to get this fault so that we can fix the
765 * problem here and not every time the kernel is
768 if (frame->tf_eflags & PSL_NT) {
769 frame->tf_eflags &= ~PSL_NT;
774 case T_TRCTRAP: /* trace trap */
776 if (frame->tf_eip == (int)IDTVEC(syscall)) {
778 * We've just entered system mode via the
779 * syscall lcall. Continue single stepping
780 * silently until the syscall handler has
785 if (frame->tf_eip == (int)IDTVEC(syscall) + 1) {
787 * The syscall handler has now saved the
788 * flags. Stop single stepping it.
790 frame->tf_eflags &= ~PSL_T;
796 * Ignore debug register trace traps due to
797 * accesses in the user's address space, which
798 * can happen under several conditions such as
799 * if a user sets a watchpoint on a buffer and
800 * then passes that buffer to a system call.
801 * We still want to get TRCTRAPS for addresses
802 * in kernel space because that is useful when
803 * debugging the kernel.
805 if (user_dbreg_trap()) {
807 * Reset breakpoint bits because the
810 load_dr6(rdr6() & 0xfffffff0);
815 * Fall through (TRCTRAP kernel mode, kernel address)
819 * If DDB is enabled, let it handle the debugger trap.
820 * Otherwise, debugger traps "can't happen".
823 MAKEMPSAFE(have_mplock);
824 if (kdb_trap (type, 0, frame))
829 MAKEMPSAFE(have_mplock);
830 trap_fatal(frame, FALSE, eva);
833 MAKEMPSAFE(have_mplock);
834 trap_fatal(frame, FALSE, eva);
838 * Ignore this trap generated from a spurious SIGTRAP.
840 * single stepping in / syscalls leads to spurious / SIGTRAP
843 * Haiku (c) 2007 Simon 'corecode' Schubert
849 * Translate fault for emulators (e.g. Linux)
851 if (*p->p_sysent->sv_transtrap)
852 i = (*p->p_sysent->sv_transtrap)(i, type);
854 MAKEMPSAFE(have_mplock);
855 trapsignal(lp, i, ucode);
858 if (type <= MAX_TRAP_MSG) {
859 uprintf("fatal process exception: %s",
861 if ((type == T_PAGEFLT) || (type == T_PROTFLT))
862 uprintf(", fault VA = 0x%lx", (u_long)eva);
874 KASSERT(crit_count == td->td_critcount,
875 ("syscall: critical section count mismatch! %d/%d",
876 crit_count, td->td_pri));
881 trap_pfault(struct trapframe *frame, int usermode, vm_offset_t eva)
884 struct vmspace *vm = NULL;
889 thread_t td = curthread;
890 struct lwp *lp = td->td_lwp;
892 va = trunc_page(eva);
893 if (usermode == FALSE) {
895 * This is a fault on kernel virtual memory.
900 * This is a fault on non-kernel virtual memory.
901 * vm is initialized above to NULL. If curproc is NULL
902 * or curproc->p_vmspace is NULL the fault is fatal.
905 vm = lp->lwp_vmspace;
913 if (frame->tf_xflags & PGEX_W)
914 ftype = VM_PROT_READ | VM_PROT_WRITE;
916 ftype = VM_PROT_READ;
918 if (map != &kernel_map) {
920 * Keep swapout from messing with us during this
930 fault_flags |= VM_FAULT_BURST;
931 if (ftype & VM_PROT_WRITE)
932 fault_flags |= VM_FAULT_DIRTY;
934 fault_flags |= VM_FAULT_NORMAL;
935 rv = vm_fault(map, va, ftype, fault_flags);
940 * Don't have to worry about process locking or stacks in the kernel.
942 rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL);
945 if (rv == KERN_SUCCESS)
949 if (td->td_gd->gd_intr_nesting_level == 0 &&
950 td->td_pcb->pcb_onfault) {
951 frame->tf_eip = (register_t)td->td_pcb->pcb_onfault;
954 trap_fatal(frame, usermode, eva);
957 return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV);
961 trap_fatal(struct trapframe *frame, int usermode, vm_offset_t eva)
963 int code, type, ss, esp;
965 code = frame->tf_xflags;
966 type = frame->tf_trapno;
968 if (type <= MAX_TRAP_MSG) {
969 kprintf("\n\nFatal trap %d: %s while in %s mode\n",
970 type, trap_msg[type],
971 (usermode ? "user" : "kernel"));
974 /* two separate prints in case of a trap on an unmapped page */
975 kprintf("mp_lock = %08x; ", mp_lock);
976 kprintf("cpuid = %d\n", mycpu->gd_cpuid);
978 if (type == T_PAGEFLT) {
979 kprintf("fault virtual address = %p\n", (void *)eva);
980 kprintf("fault code = %s %s, %s\n",
981 usermode ? "user" : "supervisor",
982 code & PGEX_W ? "write" : "read",
983 code & PGEX_P ? "protection violation" : "page not present");
985 kprintf("instruction pointer = 0x%x:0x%x\n",
986 frame->tf_cs & 0xffff, frame->tf_eip);
988 ss = frame->tf_ss & 0xffff;
991 ss = GSEL(GDATA_SEL, SEL_KPL);
992 esp = (int)&frame->tf_esp;
994 kprintf("stack pointer = 0x%x:0x%x\n", ss, esp);
995 kprintf("frame pointer = 0x%x:0x%x\n", ss, frame->tf_ebp);
996 kprintf("processor eflags = ");
997 if (frame->tf_eflags & PSL_T)
998 kprintf("trace trap, ");
999 if (frame->tf_eflags & PSL_I)
1000 kprintf("interrupt enabled, ");
1001 if (frame->tf_eflags & PSL_NT)
1002 kprintf("nested task, ");
1003 if (frame->tf_eflags & PSL_RF)
1004 kprintf("resume, ");
1006 if (frame->tf_eflags & PSL_VM)
1009 kprintf("IOPL = %d\n", (frame->tf_eflags & PSL_IOPL) >> 12);
1010 kprintf("current process = ");
1012 kprintf("%lu (%s)\n",
1013 (u_long)curproc->p_pid, curproc->p_comm ?
1014 curproc->p_comm : "");
1018 kprintf("current thread = pri %d ", curthread->td_pri);
1019 if (curthread->td_critcount)
1025 * we probably SHOULD have stopped the other CPUs before now!
1026 * another CPU COULD have been touching cpl at this moment...
1028 kprintf(" <- SMP: XXX");
1037 if ((debugger_on_panic || db_active) && kdb_trap(type, code, frame))
1040 kprintf("trap number = %d\n", type);
1041 if (type <= MAX_TRAP_MSG)
1042 panic("%s", trap_msg[type]);
1044 panic("unknown/reserved trap");
1048 * Double fault handler. Called when a fault occurs while writing
1049 * a frame for a trap/exception onto the stack. This usually occurs
1050 * when the stack overflows (such is the case with infinite recursion,
1053 * XXX Note that the current PTD gets replaced by IdlePTD when the
1054 * task switch occurs. This means that the stack that was active at
1055 * the time of the double fault is not available at <kstack> unless
1056 * the machine was idle when the double fault occurred. The downside
1057 * of this is that "trace <ebp>" in ddb won't work.
1060 dblfault_handler(void)
1062 struct mdglobaldata *gd = mdcpu;
1064 kprintf("\nFatal double fault:\n");
1065 kprintf("eip = 0x%x\n", gd->gd_common_tss.tss_eip);
1066 kprintf("esp = 0x%x\n", gd->gd_common_tss.tss_esp);
1067 kprintf("ebp = 0x%x\n", gd->gd_common_tss.tss_ebp);
1069 /* two separate prints in case of a trap on an unmapped page */
1070 kprintf("mp_lock = %08x; ", mp_lock);
1071 kprintf("cpuid = %d\n", mycpu->gd_cpuid);
1073 panic("double fault");
1077 * syscall2 - MP aware system call request C handler
1079 * A system call is essentially treated as a trap except that the
1080 * MP lock is not held on entry or return. We are responsible for
1081 * obtaining the MP lock if necessary and for handling ASTs
1082 * (e.g. a task switch) prior to return.
1087 syscall2(struct trapframe *frame)
1089 struct thread *td = curthread;
1090 struct proc *p = td->td_proc;
1091 struct lwp *lp = td->td_lwp;
1093 struct sysent *callp;
1094 register_t orig_tf_eflags;
1099 int crit_count = td->td_critcount;
1102 int have_mplock = 0;
1105 union sysunion args;
1107 KTR_LOG(kernentry_syscall, lp->lwp_proc->p_pid, lp->lwp_tid,
1111 KASSERT(td->td_mpcount == 0, ("badmpcount syscall2 from %p", (void *)frame->tf_eip));
1112 if (syscall_mpsafe == 0)
1113 MAKEMPSAFE(have_mplock);
1115 userenter(td, p); /* lazy raise our priority */
1120 sticks = (int)td->td_sticks;
1121 orig_tf_eflags = frame->tf_eflags;
1124 * Virtual kernel intercept - if a VM context managed by a virtual
1125 * kernel issues a system call the virtual kernel handles it, not us.
1126 * Restore the virtual kernel context and return from its system
1127 * call. The current frame is copied out to the virtual kernel.
1129 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) {
1130 vkernel_trap(lp, frame);
1131 error = EJUSTRETURN;
1136 * Get the system call parameters and account for time
1138 lp->lwp_md.md_regs = frame;
1139 params = (caddr_t)frame->tf_esp + sizeof(int);
1140 code = frame->tf_eax;
1142 if (p->p_sysent->sv_prepsyscall) {
1143 (*p->p_sysent->sv_prepsyscall)(
1144 frame, (int *)(&args.nosys.sysmsg + 1),
1148 * Need to check if this is a 32 bit or 64 bit syscall.
1149 * fuword is MP aware.
1151 if (code == SYS_syscall) {
1153 * Code is first argument, followed by actual args.
1155 code = fuword(params);
1156 params += sizeof(int);
1157 } else if (code == SYS___syscall) {
1159 * Like syscall, but code is a quad, so as to maintain
1160 * quad alignment for the rest of the arguments.
1162 code = fuword(params);
1163 params += sizeof(quad_t);
1167 code &= p->p_sysent->sv_mask;
1168 if (code >= p->p_sysent->sv_size)
1169 callp = &p->p_sysent->sv_table[0];
1171 callp = &p->p_sysent->sv_table[code];
1173 narg = callp->sy_narg & SYF_ARGMASK;
1176 * copyin is MP aware, but the tracing code is not
1178 if (narg && params) {
1179 error = copyin(params, (caddr_t)(&args.nosys.sysmsg + 1),
1180 narg * sizeof(register_t));
1183 if (KTRPOINT(td, KTR_SYSCALL)) {
1184 MAKEMPSAFE(have_mplock);
1186 ktrsyscall(lp, code, narg,
1187 (void *)(&args.nosys.sysmsg + 1));
1195 if (KTRPOINT(td, KTR_SYSCALL)) {
1196 MAKEMPSAFE(have_mplock);
1197 ktrsyscall(lp, code, narg, (void *)(&args.nosys.sysmsg + 1));
1202 * For traditional syscall code edx is left untouched when 32 bit
1203 * results are returned. Since edx is loaded from fds[1] when the
1204 * system call returns we pre-set it here.
1206 args.sysmsg_fds[0] = 0;
1207 args.sysmsg_fds[1] = frame->tf_edx;
1210 * The syscall might manipulate the trap frame. If it does it
1211 * will probably return EJUSTRETURN.
1213 args.sysmsg_frame = frame;
1215 STOPEVENT(p, S_SCE, narg); /* MP aware */
1218 * NOTE: All system calls run MPSAFE now. The system call itself
1219 * is responsible for getting the MP lock.
1221 error = (*callp->sy_call)(&args);
1224 kprintf("system call %d returned %d\n", code, error);
1229 * MP SAFE (we may or may not have the MP lock at this point)
1234 * Reinitialize proc pointer `p' as it may be different
1235 * if this is a child returning from fork syscall.
1238 lp = curthread->td_lwp;
1239 frame->tf_eax = args.sysmsg_fds[0];
1240 frame->tf_edx = args.sysmsg_fds[1];
1241 frame->tf_eflags &= ~PSL_C;
1245 * Reconstruct pc, assuming lcall $X,y is 7 bytes,
1246 * int 0x80 is 2 bytes. We saved this in tf_err.
1248 frame->tf_eip -= frame->tf_err;
1253 panic("Unexpected EASYNC return value (for now)");
1256 if (p->p_sysent->sv_errsize) {
1257 if (error >= p->p_sysent->sv_errsize)
1258 error = -1; /* XXX */
1260 error = p->p_sysent->sv_errtbl[error];
1262 frame->tf_eax = error;
1263 frame->tf_eflags |= PSL_C;
1268 * Traced syscall. trapsignal() is not MP aware.
1270 if ((orig_tf_eflags & PSL_T) /*&& !(orig_tf_eflags & PSL_VM)*/) {
1271 MAKEMPSAFE(have_mplock);
1272 frame->tf_eflags &= ~PSL_T;
1273 trapsignal(lp, SIGTRAP, TRAP_TRACE);
1277 * Handle reschedule and other end-of-syscall issues
1279 userret(lp, frame, sticks);
1282 if (KTRPOINT(td, KTR_SYSRET)) {
1283 MAKEMPSAFE(have_mplock);
1284 ktrsysret(lp, code, error, args.sysmsg_result);
1289 * This works because errno is findable through the
1290 * register set. If we ever support an emulation where this
1291 * is not the case, this code will need to be revisited.
1293 STOPEVENT(p, S_SCX, code);
1298 * Release the MP lock if we had to get it
1300 KASSERT(td->td_mpcount == have_mplock,
1301 ("badmpcount syscall2/end from %p", (void *)frame->tf_eip));
1305 KTR_LOG(kernentry_syscall_ret, lp->lwp_proc->p_pid, lp->lwp_tid, error);
1307 KASSERT(crit_count == td->td_critcount,
1308 ("syscall: critical section count mismatch! %d/%d",
1309 crit_count, td->td_pri));
1314 * NOTE: mplock not held at any point
1317 fork_return(struct lwp *lp, struct trapframe *frame)
1319 frame->tf_eax = 0; /* Child returns zero */
1320 frame->tf_eflags &= ~PSL_C; /* success */
1323 generic_lwp_return(lp, frame);
1324 KTR_LOG(kernentry_fork_ret, lp->lwp_proc->p_pid, lp->lwp_tid);
1328 * Simplified back end of syscall(), used when returning from fork()
1329 * directly into user mode.
1331 * This code will return back into the fork trampoline code which then
1334 * NOTE: The mplock is not held at any point.
1337 generic_lwp_return(struct lwp *lp, struct trapframe *frame)
1339 struct proc *p = lp->lwp_proc;
1342 * Newly forked processes are given a kernel priority. We have to
1343 * adjust the priority to a normal user priority and fake entry
1344 * into the kernel (call userenter()) to install a passive release
1345 * function just in case userret() decides to stop the process. This
1346 * can occur when ^Z races a fork. If we do not install the passive
1347 * release function the current process designation will not be
1348 * released when the thread goes to sleep.
1350 lwkt_setpri_self(TDPRI_USER_NORM);
1351 userenter(lp->lwp_thread, p);
1352 userret(lp, frame, 0);
1354 if (KTRPOINT(lp->lwp_thread, KTR_SYSRET))
1355 ktrsysret(lp, SYS_fork, 0, 0);
1357 p->p_flag |= P_PASSIVE_ACQ;
1359 p->p_flag &= ~P_PASSIVE_ACQ;
1363 * doreti has turned into this. The frame is directly on the stack. We
1364 * pull everything else we need (fpu and tls context) from the current
1367 * Note on fpu interactions: In a virtual kernel, the fpu context for
1368 * an emulated user mode process is not shared with the virtual kernel's
1369 * fpu context, so we only have to 'stack' fpu contexts within the virtual
1370 * kernel itself, and not even then since the signal() contexts that we care
1371 * about save and restore the FPU state (I think anyhow).
1373 * vmspace_ctl() returns an error only if it had problems instaling the
1374 * context we supplied or problems copying data to/from our VM space.
1377 go_user(struct intrframe *frame)
1379 struct trapframe *tf = (void *)&frame->if_gs;
1383 * Interrupts may be disabled on entry, make sure all signals
1384 * can be received before beginning our loop.
1389 * Switch to the current simulated user process, then call
1390 * user_trap() when we break out of it (usually due to a signal).
1394 * Tell the real kernel whether it is ok to use the FP
1397 * The critical section is required to prevent an interrupt
1398 * from causing a preemptive task switch and changing
1402 if (mdcpu->gd_npxthread == curthread) {
1403 tf->tf_xflags &= ~PGEX_FPFAULT;
1405 tf->tf_xflags |= PGEX_FPFAULT;
1409 * Run emulated user process context. This call interlocks
1410 * with new mailbox signals.
1412 * Set PGEX_U unconditionally, indicating a user frame (the
1413 * bit is normally set only by T_PAGEFLT).
1415 r = vmspace_ctl(&curproc->p_vmspace->vm_pmap, VMSPACE_CTL_RUN,
1416 tf, &curthread->td_savevext);
1418 frame->if_xflags |= PGEX_U;
1420 kprintf("GO USER %d trap %d EVA %08x EIP %08x ESP %08x XFLAGS %02x/%02x\n",
1421 r, tf->tf_trapno, tf->tf_err, tf->tf_eip, tf->tf_esp,
1422 tf->tf_xflags, frame->if_xflags);
1426 panic("vmspace_ctl failed error %d", errno);
1428 if (tf->tf_trapno) {
1432 if (mycpu->gd_reqflags & RQF_AST_MASK) {
1433 tf->tf_trapno = T_ASTFLT;
1441 * If PGEX_FPFAULT is set then set FP_VIRTFP in the PCB to force a T_DNA
1442 * fault (which is then passed back to the virtual kernel) if an attempt is
1443 * made to use the FP unit.
1445 * XXX this is a fairly big hack.
1448 set_vkernel_fp(struct trapframe *frame)
1450 struct thread *td = curthread;
1452 if (frame->tf_xflags & PGEX_FPFAULT) {
1453 td->td_pcb->pcb_flags |= FP_VIRTFP;
1454 if (mdcpu->gd_npxthread == td)
1457 td->td_pcb->pcb_flags &= ~FP_VIRTFP;
1462 * Called from vkernel_trap() to fixup the vkernel's syscall
1463 * frame for vmspace_ctl() return.
1466 cpu_vkernel_trap(struct trapframe *frame, int error)
1468 frame->tf_eax = error;
1470 frame->tf_eflags |= PSL_C;
1472 frame->tf_eflags &= ~PSL_C;