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 extern int trapwrite (unsigned addr);
118 static int trap_pfault (struct trapframe *, int, vm_offset_t);
119 static void trap_fatal (struct trapframe *, int, vm_offset_t);
120 void dblfault_handler (void);
123 extern inthand_t IDTVEC(syscall);
126 #define MAX_TRAP_MSG 28
127 static char *trap_msg[] = {
129 "privileged instruction fault", /* 1 T_PRIVINFLT */
131 "breakpoint instruction fault", /* 3 T_BPTFLT */
134 "arithmetic trap", /* 6 T_ARITHTRAP */
135 "system forced exception", /* 7 T_ASTFLT */
137 "general protection fault", /* 9 T_PROTFLT */
138 "trace trap", /* 10 T_TRCTRAP */
140 "page fault", /* 12 T_PAGEFLT */
142 "alignment fault", /* 14 T_ALIGNFLT */
146 "integer divide fault", /* 18 T_DIVIDE */
147 "non-maskable interrupt trap", /* 19 T_NMI */
148 "overflow trap", /* 20 T_OFLOW */
149 "FPU bounds check fault", /* 21 T_BOUND */
150 "FPU device not available", /* 22 T_DNA */
151 "double fault", /* 23 T_DOUBLEFLT */
152 "FPU operand fetch fault", /* 24 T_FPOPFLT */
153 "invalid TSS fault", /* 25 T_TSSFLT */
154 "segment not present fault", /* 26 T_SEGNPFLT */
155 "stack fault", /* 27 T_STKFLT */
156 "machine check trap", /* 28 T_MCHK */
160 static int ddb_on_nmi = 1;
161 SYSCTL_INT(_machdep, OID_AUTO, ddb_on_nmi, CTLFLAG_RW,
162 &ddb_on_nmi, 0, "Go to DDB on NMI");
164 static int panic_on_nmi = 1;
165 SYSCTL_INT(_machdep, OID_AUTO, panic_on_nmi, CTLFLAG_RW,
166 &panic_on_nmi, 0, "Panic on NMI");
167 static int fast_release;
168 SYSCTL_INT(_machdep, OID_AUTO, fast_release, CTLFLAG_RW,
169 &fast_release, 0, "Passive Release was optimal");
170 static int slow_release;
171 SYSCTL_INT(_machdep, OID_AUTO, slow_release, CTLFLAG_RW,
172 &slow_release, 0, "Passive Release was nonoptimal");
174 static int syscall_mpsafe = 1;
175 SYSCTL_INT(_kern, OID_AUTO, syscall_mpsafe, CTLFLAG_RW,
176 &syscall_mpsafe, 0, "Allow MPSAFE marked syscalls to run without BGL");
177 TUNABLE_INT("kern.syscall_mpsafe", &syscall_mpsafe);
178 static int trap_mpsafe = 1;
179 SYSCTL_INT(_kern, OID_AUTO, trap_mpsafe, CTLFLAG_RW,
180 &trap_mpsafe, 0, "Allow traps to mostly run without the BGL");
181 TUNABLE_INT("kern.trap_mpsafe", &trap_mpsafe);
184 MALLOC_DEFINE(M_SYSMSG, "sysmsg", "sysmsg structure");
185 extern int max_sysmsg;
188 * Passively intercepts the thread switch function to increase
189 * the thread priority from a user priority to a kernel priority, reducing
190 * syscall and trap overhead for the case where no switch occurs.
192 * Synchronizes td_ucred with p_ucred. This is used by system calls,
193 * signal handling, faults, AST traps, and anything else that enters the
194 * kernel from userland and provides the kernel with a stable read-only
195 * copy of the process ucred.
198 userenter(struct thread *curtd, struct proc *curp)
203 curtd->td_release = lwkt_passive_release;
205 if (curtd->td_ucred != curp->p_ucred) {
206 ncred = crhold(curp->p_ucred);
207 ocred = curtd->td_ucred;
208 curtd->td_ucred = ncred;
215 * Handle signals, upcalls, profiling, and other AST's and/or tasks that
216 * must be completed before we can return to or try to return to userland.
218 * Note that td_sticks is a 64 bit quantity, but there's no point doing 64
219 * arithmatic on the delta calculation so the absolute tick values are
220 * truncated to an integer.
223 userret(struct lwp *lp, struct trapframe *frame, int sticks)
225 struct proc *p = lp->lwp_proc;
229 * Charge system time if profiling. Note: times are in microseconds.
230 * This may do a copyout and block, so do it first even though it
231 * means some system time will be charged as user time.
233 if (p->p_flag & P_PROFIL) {
234 addupc_task(p, frame->tf_eip,
235 (u_int)((int)lp->lwp_thread->td_sticks - sticks));
240 * If the jungle wants us dead, so be it.
242 if (lp->lwp_flag & LWP_WEXIT) {
245 rel_mplock(); /* NOT REACHED */
249 * Block here if we are in a stopped state.
251 if (p->p_stat == SSTOP) {
259 * Post any pending upcalls
261 if (p->p_flag & P_UPCALLPEND) {
263 p->p_flag &= ~P_UPCALLPEND;
270 * Post any pending signals
272 if ((sig = CURSIG_TRACE(lp)) != 0) {
280 * block here if we are swapped out, but still process signals
281 * (such as SIGKILL). proc0 (the swapin scheduler) is already
282 * aware of our situation, we do not have to wake it up.
284 if (p->p_flag & P_SWAPPEDOUT) {
286 p->p_flag |= P_SWAPWAIT;
288 if (p->p_flag & P_SWAPWAIT)
289 tsleep(p, PCATCH, "SWOUT", 0);
290 p->p_flag &= ~P_SWAPWAIT;
296 * Make sure postsig() handled request to restore old signal mask after
297 * running signal handler.
299 KKASSERT((lp->lwp_flag & LWP_OLDMASK) == 0);
303 * Cleanup from userenter and any passive release that might have occured.
304 * We must reclaim the current-process designation before we can return
305 * to usermode. We also handle both LWKT and USER reschedule requests.
308 userexit(struct lwp *lp)
310 struct thread *td = lp->lwp_thread;
311 /* globaldata_t gd = td->td_gd; */
314 * Handle stop requests at kernel priority. Any requests queued
315 * after this loop will generate another AST.
317 while (lp->lwp_proc->p_stat == SSTOP) {
324 * Reduce our priority in preparation for a return to userland. If
325 * our passive release function was still in place, our priority was
326 * never raised and does not need to be reduced.
328 lwkt_passive_recover(td);
331 * Become the current user scheduled process if we aren't already,
332 * and deal with reschedule requests and other factors.
334 lp->lwp_proc->p_usched->acquire_curproc(lp);
335 /* WARNING: we may have migrated cpu's */
336 /* gd = td->td_gd; */
339 #if !defined(KTR_KERNENTRY)
340 #define KTR_KERNENTRY KTR_ALL
342 KTR_INFO_MASTER(kernentry);
343 KTR_INFO(KTR_KERNENTRY, kernentry, trap, 0, "pid=%d, tid=%d, trapno=%d, eva=%p",
344 sizeof(int) + sizeof(int) + sizeof(int) + sizeof(vm_offset_t));
345 KTR_INFO(KTR_KERNENTRY, kernentry, trap_ret, 0, "pid=%d, tid=%d",
346 sizeof(int) + sizeof(int));
347 KTR_INFO(KTR_KERNENTRY, kernentry, syscall, 0, "pid=%d, tid=%d, call=%d",
348 sizeof(int) + sizeof(int) + sizeof(int));
349 KTR_INFO(KTR_KERNENTRY, kernentry, syscall_ret, 0, "pid=%d, tid=%d, err=%d",
350 sizeof(int) + sizeof(int) + sizeof(int));
351 KTR_INFO(KTR_KERNENTRY, kernentry, fork_ret, 0, "pid=%d, tid=%d",
352 sizeof(int) + sizeof(int));
355 * Exception, fault, and trap interface to the kernel.
356 * This common code is called from assembly language IDT gate entry
357 * routines that prepare a suitable stack frame, and restore this
358 * frame after the exception has been processed.
360 * This function is also called from doreti in an interlock to handle ASTs.
361 * For example: hardwareint->INTROUTINE->(set ast)->doreti->trap
363 * NOTE! We have to retrieve the fault address prior to obtaining the
364 * MP lock because get_mplock() may switch out. YYY cr2 really ought
365 * to be retrieved by the assembly code, not here.
367 * XXX gd_trap_nesting_level currently prevents lwkt_switch() from panicing
368 * if an attempt is made to switch from a fast interrupt or IPI. This is
369 * necessary to properly take fatal kernel traps on SMP machines if
370 * get_mplock() has to block.
374 user_trap(struct trapframe *frame)
376 struct globaldata *gd = mycpu;
377 struct thread *td = gd->gd_curthread;
378 struct lwp *lp = td->td_lwp;
381 int i = 0, ucode = 0, type, code;
386 int crit_count = td->td_pri & ~TDPRI_MASK;
393 * This is a bad kludge to avoid changing the various trapframe
394 * structures. Because we are enabled as a virtual kernel,
395 * the original tf_err field will be passed to us shifted 16
396 * over in the tf_trapno field for T_PAGEFLT.
398 if (frame->tf_trapno == T_PAGEFLT)
403 kprintf("USER_TRAP AT %08x xflags %d trapno %d eva %08x\n",
404 frame->tf_eip, frame->tf_xflags, frame->tf_trapno, eva);
408 * Everything coming from user mode runs through user_trap,
409 * including system calls.
411 if (frame->tf_trapno == T_SYSCALL80) {
416 KTR_LOG(kernentry_trap, lp->lwp_proc->p_pid, lp->lwp_tid,
417 frame->tf_trapno, eva);
421 eva = (frame->tf_trapno == T_PAGEFLT ? rcr2() : 0);
422 ++gd->gd_trap_nesting_level;
423 MAKEMPSAFE(have_mplock);
424 trap_fatal(frame, TRUE, eva);
425 --gd->gd_trap_nesting_level;
430 ++gd->gd_trap_nesting_level;
432 if (trap_mpsafe == 0)
433 MAKEMPSAFE(have_mplock);
436 --gd->gd_trap_nesting_level;
438 #if defined(I586_CPU) && !defined(NO_F00F_HACK)
441 type = frame->tf_trapno;
442 code = frame->tf_err;
446 sticks = (int)td->td_sticks;
447 lp->lwp_md.md_regs = frame;
450 case T_PRIVINFLT: /* privileged instruction fault */
455 case T_BPTFLT: /* bpt instruction fault */
456 case T_TRCTRAP: /* trace trap */
457 frame->tf_eflags &= ~PSL_T;
462 case T_ARITHTRAP: /* arithmetic trap */
467 case T_ASTFLT: /* Allow process switch */
468 mycpu->gd_cnt.v_soft++;
469 if (mycpu->gd_reqflags & RQF_AST_OWEUPC) {
470 atomic_clear_int_nonlocked(&mycpu->gd_reqflags,
472 addupc_task(p, p->p_prof.pr_addr,
478 * The following two traps can happen in
479 * vm86 mode, and, if so, we want to handle
482 case T_PROTFLT: /* general protection fault */
483 case T_STKFLT: /* stack fault */
485 if (frame->tf_eflags & PSL_VM) {
486 i = vm86_emulate((struct vm86frame *)frame);
493 ucode = (type == T_PROTFLT) ? BUS_OBJERR : BUS_ADRERR;
495 case T_SEGNPFLT: /* segment not present fault */
499 case T_TSSFLT: /* invalid TSS fault */
500 case T_DOUBLEFLT: /* double fault */
505 ucode = code + BUS_SEGM_FAULT ; /* XXX: ???*/
511 case T_PAGEFLT: /* page fault */
512 MAKEMPSAFE(have_mplock);
513 i = trap_pfault(frame, TRUE, eva);
516 #if defined(I586_CPU) && !defined(NO_F00F_HACK)
532 case T_DIVIDE: /* integer divide fault */
539 MAKEMPSAFE(have_mplock);
540 /* machine/parity/power fail/"kitchen sink" faults */
541 if (isa_nmi(code) == 0) {
544 * NMI can be hooked up to a pushbutton
548 kprintf ("NMI ... going to debugger\n");
549 kdb_trap (type, 0, frame);
553 } else if (panic_on_nmi)
554 panic("NMI indicates hardware failure");
556 #endif /* NISA > 0 */
558 case T_OFLOW: /* integer overflow fault */
563 case T_BOUND: /* bounds check fault */
570 * Virtual kernel intercept - pass the DNA exception
571 * to the (emulated) virtual kernel if it asked to handle
572 * it. This occurs when the virtual kernel is holding
573 * onto the FP context for a different emulated
574 * process then the one currently running.
576 * We must still call npxdna() since we may have
577 * saved FP state that the (emulated) virtual kernel
578 * needs to hand over to a different emulated process.
580 if (lp->lwp_vkernel && lp->lwp_vkernel->ve &&
581 (td->td_pcb->pcb_flags & FP_VIRTFP)
588 * The kernel may have switched out the FP unit's
589 * state, causing the user process to take a fault
590 * when it tries to use the FP unit. Restore the
596 if (!pmath_emulate) {
598 ucode = FPE_FPU_NP_TRAP;
601 i = (*pmath_emulate)(frame);
603 if (!(frame->tf_eflags & PSL_T))
605 frame->tf_eflags &= ~PSL_T;
608 /* else ucode = emulator_only_knows() XXX */
611 case T_FPOPFLT: /* FPU operand fetch fault */
616 case T_XMMFLT: /* SIMD floating-point exception */
623 * Virtual kernel intercept - if the fault is directly related to a
624 * VM context managed by a virtual kernel then let the virtual kernel
627 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) {
628 vkernel_trap(lp, frame);
633 * Translate fault for emulators (e.g. Linux)
635 if (*p->p_sysent->sv_transtrap)
636 i = (*p->p_sysent->sv_transtrap)(i, type);
638 MAKEMPSAFE(have_mplock);
639 trapsignal(lp, i, ucode);
642 if (type <= MAX_TRAP_MSG) {
643 uprintf("fatal process exception: %s",
645 if ((type == T_PAGEFLT) || (type == T_PROTFLT))
646 uprintf(", fault VA = 0x%lx", (u_long)eva);
653 KASSERT(td->td_mpcount == have_mplock, ("badmpcount trap/end from %p", (void *)frame->tf_eip));
655 userret(lp, frame, sticks);
662 KTR_LOG(kernentry_trap_ret, lp->lwp_proc->p_pid, lp->lwp_tid);
664 KASSERT(crit_count == (td->td_pri & ~TDPRI_MASK),
665 ("syscall: critical section count mismatch! %d/%d",
666 crit_count / TDPRI_CRIT, td->td_pri / TDPRI_CRIT));
671 kern_trap(struct trapframe *frame)
673 struct globaldata *gd = mycpu;
674 struct thread *td = gd->gd_curthread;
677 int i = 0, ucode = 0, type, code;
682 int crit_count = td->td_pri & ~TDPRI_MASK;
689 if (frame->tf_trapno == T_PAGEFLT)
696 ++gd->gd_trap_nesting_level;
697 MAKEMPSAFE(have_mplock);
698 trap_fatal(frame, FALSE, eva);
699 --gd->gd_trap_nesting_level;
704 ++gd->gd_trap_nesting_level;
707 if (trap_mpsafe == 0)
708 MAKEMPSAFE(have_mplock);
711 --gd->gd_trap_nesting_level;
713 type = frame->tf_trapno;
714 code = frame->tf_err;
722 case T_PAGEFLT: /* page fault */
723 MAKEMPSAFE(have_mplock);
724 trap_pfault(frame, FALSE, eva);
730 * The kernel may be using npx for copying or other
733 panic("kernel NPX should not happen");
739 case T_PROTFLT: /* general protection fault */
740 case T_SEGNPFLT: /* segment not present fault */
742 * Invalid segment selectors and out of bounds
743 * %eip's and %esp's can be set up in user mode.
744 * This causes a fault in kernel mode when the
745 * kernel tries to return to user mode. We want
746 * to get this fault so that we can fix the
747 * problem here and not have to check all the
748 * selectors and pointers when the user changes
751 if (mycpu->gd_intr_nesting_level == 0) {
752 if (td->td_pcb->pcb_onfault) {
754 (register_t)td->td_pcb->pcb_onfault;
762 * PSL_NT can be set in user mode and isn't cleared
763 * automatically when the kernel is entered. This
764 * causes a TSS fault when the kernel attempts to
765 * `iret' because the TSS link is uninitialized. We
766 * want to get this fault so that we can fix the
767 * problem here and not every time the kernel is
770 if (frame->tf_eflags & PSL_NT) {
771 frame->tf_eflags &= ~PSL_NT;
776 case T_TRCTRAP: /* trace trap */
778 if (frame->tf_eip == (int)IDTVEC(syscall)) {
780 * We've just entered system mode via the
781 * syscall lcall. Continue single stepping
782 * silently until the syscall handler has
787 if (frame->tf_eip == (int)IDTVEC(syscall) + 1) {
789 * The syscall handler has now saved the
790 * flags. Stop single stepping it.
792 frame->tf_eflags &= ~PSL_T;
798 * Ignore debug register trace traps due to
799 * accesses in the user's address space, which
800 * can happen under several conditions such as
801 * if a user sets a watchpoint on a buffer and
802 * then passes that buffer to a system call.
803 * We still want to get TRCTRAPS for addresses
804 * in kernel space because that is useful when
805 * debugging the kernel.
807 if (user_dbreg_trap()) {
809 * Reset breakpoint bits because the
812 load_dr6(rdr6() & 0xfffffff0);
817 * Fall through (TRCTRAP kernel mode, kernel address)
821 * If DDB is enabled, let it handle the debugger trap.
822 * Otherwise, debugger traps "can't happen".
825 MAKEMPSAFE(have_mplock);
826 if (kdb_trap (type, 0, frame))
831 MAKEMPSAFE(have_mplock);
832 trap_fatal(frame, FALSE, eva);
835 MAKEMPSAFE(have_mplock);
836 trap_fatal(frame, FALSE, eva);
840 * Ignore this trap generated from a spurious SIGTRAP.
842 * single stepping in / syscalls leads to spurious / SIGTRAP
845 * Haiku (c) 2007 Simon 'corecode' Schubert
851 * Translate fault for emulators (e.g. Linux)
853 if (*p->p_sysent->sv_transtrap)
854 i = (*p->p_sysent->sv_transtrap)(i, type);
856 MAKEMPSAFE(have_mplock);
857 trapsignal(lp, i, ucode);
860 if (type <= MAX_TRAP_MSG) {
861 uprintf("fatal process exception: %s",
863 if ((type == T_PAGEFLT) || (type == T_PROTFLT))
864 uprintf(", fault VA = 0x%lx", (u_long)eva);
876 KASSERT(crit_count == (td->td_pri & ~TDPRI_MASK),
877 ("syscall: critical section count mismatch! %d/%d",
878 crit_count / TDPRI_CRIT, td->td_pri / TDPRI_CRIT));
883 trap_pfault(struct trapframe *frame, int usermode, vm_offset_t eva)
886 struct vmspace *vm = NULL;
890 thread_t td = curthread;
891 struct lwp *lp = td->td_lwp;
893 va = trunc_page(eva);
894 if (usermode == FALSE) {
896 * This is a fault on kernel virtual memory.
901 * This is a fault on non-kernel virtual memory.
902 * vm is initialized above to NULL. If curproc is NULL
903 * or curproc->p_vmspace is NULL the fault is fatal.
906 vm = lp->lwp_vmspace;
914 if (frame->tf_xflags & PGEX_W)
915 ftype = VM_PROT_READ | VM_PROT_WRITE;
917 ftype = VM_PROT_READ;
919 if (map != &kernel_map) {
921 * Keep swapout from messing with us during this
927 * Grow the stack if necessary
929 /* grow_stack returns false only if va falls into
930 * a growable stack region and the stack growth
931 * fails. It returns true if va was not within
932 * a growable stack region, or if the stack
935 if (!grow_stack (lp->lwp_proc, va)) {
941 /* Fault in the user page: */
942 rv = vm_fault(map, va, ftype,
943 (ftype & VM_PROT_WRITE) ? VM_FAULT_DIRTY
949 * Don't have to worry about process locking or stacks in the kernel.
951 rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL);
954 if (rv == KERN_SUCCESS)
958 if (td->td_gd->gd_intr_nesting_level == 0 &&
959 td->td_pcb->pcb_onfault) {
960 frame->tf_eip = (register_t)td->td_pcb->pcb_onfault;
963 trap_fatal(frame, usermode, eva);
966 return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV);
970 trap_fatal(struct trapframe *frame, int usermode, vm_offset_t eva)
972 int code, type, ss, esp;
974 code = frame->tf_xflags;
975 type = frame->tf_trapno;
977 if (type <= MAX_TRAP_MSG) {
978 kprintf("\n\nFatal trap %d: %s while in %s mode\n",
979 type, trap_msg[type],
980 (usermode ? "user" : "kernel"));
983 /* two separate prints in case of a trap on an unmapped page */
984 kprintf("mp_lock = %08x; ", mp_lock);
985 kprintf("cpuid = %d\n", mycpu->gd_cpuid);
987 if (type == T_PAGEFLT) {
988 kprintf("fault virtual address = %p\n", (void *)eva);
989 kprintf("fault code = %s %s, %s\n",
990 usermode ? "user" : "supervisor",
991 code & PGEX_W ? "write" : "read",
992 code & PGEX_P ? "protection violation" : "page not present");
994 kprintf("instruction pointer = 0x%x:0x%x\n",
995 frame->tf_cs & 0xffff, frame->tf_eip);
997 ss = frame->tf_ss & 0xffff;
1000 ss = GSEL(GDATA_SEL, SEL_KPL);
1001 esp = (int)&frame->tf_esp;
1003 kprintf("stack pointer = 0x%x:0x%x\n", ss, esp);
1004 kprintf("frame pointer = 0x%x:0x%x\n", ss, frame->tf_ebp);
1005 kprintf("processor eflags = ");
1006 if (frame->tf_eflags & PSL_T)
1007 kprintf("trace trap, ");
1008 if (frame->tf_eflags & PSL_I)
1009 kprintf("interrupt enabled, ");
1010 if (frame->tf_eflags & PSL_NT)
1011 kprintf("nested task, ");
1012 if (frame->tf_eflags & PSL_RF)
1013 kprintf("resume, ");
1015 if (frame->tf_eflags & PSL_VM)
1018 kprintf("IOPL = %d\n", (frame->tf_eflags & PSL_IOPL) >> 12);
1019 kprintf("current process = ");
1021 kprintf("%lu (%s)\n",
1022 (u_long)curproc->p_pid, curproc->p_comm ?
1023 curproc->p_comm : "");
1027 kprintf("current thread = pri %d ", curthread->td_pri);
1028 if (curthread->td_pri >= TDPRI_CRIT)
1034 * we probably SHOULD have stopped the other CPUs before now!
1035 * another CPU COULD have been touching cpl at this moment...
1037 kprintf(" <- SMP: XXX");
1046 if ((debugger_on_panic || db_active) && kdb_trap(type, code, frame))
1049 kprintf("trap number = %d\n", type);
1050 if (type <= MAX_TRAP_MSG)
1051 panic("%s", trap_msg[type]);
1053 panic("unknown/reserved trap");
1057 * Double fault handler. Called when a fault occurs while writing
1058 * a frame for a trap/exception onto the stack. This usually occurs
1059 * when the stack overflows (such is the case with infinite recursion,
1062 * XXX Note that the current PTD gets replaced by IdlePTD when the
1063 * task switch occurs. This means that the stack that was active at
1064 * the time of the double fault is not available at <kstack> unless
1065 * the machine was idle when the double fault occurred. The downside
1066 * of this is that "trace <ebp>" in ddb won't work.
1069 dblfault_handler(void)
1071 struct mdglobaldata *gd = mdcpu;
1073 kprintf("\nFatal double fault:\n");
1074 kprintf("eip = 0x%x\n", gd->gd_common_tss.tss_eip);
1075 kprintf("esp = 0x%x\n", gd->gd_common_tss.tss_esp);
1076 kprintf("ebp = 0x%x\n", gd->gd_common_tss.tss_ebp);
1078 /* two separate prints in case of a trap on an unmapped page */
1079 kprintf("mp_lock = %08x; ", mp_lock);
1080 kprintf("cpuid = %d\n", mycpu->gd_cpuid);
1082 panic("double fault");
1086 * Compensate for 386 brain damage (missing URKR).
1087 * This is a little simpler than the pagefault handler in trap() because
1088 * it the page tables have already been faulted in and high addresses
1089 * are thrown out early for other reasons.
1092 trapwrite(unsigned addr)
1099 va = trunc_page((vm_offset_t)addr);
1101 * XXX - MAX is END. Changed > to >= for temp. fix.
1103 if (va >= VM_MAX_USER_ADDRESS)
1106 lp = curthread->td_lwp;
1107 vm = lp->lwp_vmspace;
1109 PHOLD(lp->lwp_proc);
1111 if (!grow_stack (lp->lwp_proc, va)) {
1112 PRELE(lp->lwp_proc);
1117 * fault the data page
1119 rv = vm_fault(&vm->vm_map, va, VM_PROT_WRITE, VM_FAULT_DIRTY);
1121 PRELE(lp->lwp_proc);
1123 if (rv != KERN_SUCCESS)
1130 * syscall2 - MP aware system call request C handler
1132 * A system call is essentially treated as a trap except that the
1133 * MP lock is not held on entry or return. We are responsible for
1134 * obtaining the MP lock if necessary and for handling ASTs
1135 * (e.g. a task switch) prior to return.
1140 syscall2(struct trapframe *frame)
1142 struct thread *td = curthread;
1143 struct proc *p = td->td_proc;
1144 struct lwp *lp = td->td_lwp;
1146 struct sysent *callp;
1147 register_t orig_tf_eflags;
1152 int crit_count = td->td_pri & ~TDPRI_MASK;
1155 int have_mplock = 0;
1158 union sysunion args;
1160 KTR_LOG(kernentry_syscall, lp->lwp_proc->p_pid, lp->lwp_tid,
1164 KASSERT(td->td_mpcount == 0, ("badmpcount syscall2 from %p", (void *)frame->tf_eip));
1165 if (syscall_mpsafe == 0)
1166 MAKEMPSAFE(have_mplock);
1168 userenter(td, p); /* lazy raise our priority */
1173 sticks = (int)td->td_sticks;
1174 orig_tf_eflags = frame->tf_eflags;
1177 * Virtual kernel intercept - if a VM context managed by a virtual
1178 * kernel issues a system call the virtual kernel handles it, not us.
1179 * Restore the virtual kernel context and return from its system
1180 * call. The current frame is copied out to the virtual kernel.
1182 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) {
1183 error = vkernel_trap(lp, frame);
1184 frame->tf_eax = error;
1186 frame->tf_eflags |= PSL_C;
1187 error = EJUSTRETURN;
1192 * Get the system call parameters and account for time
1194 lp->lwp_md.md_regs = frame;
1195 params = (caddr_t)frame->tf_esp + sizeof(int);
1196 code = frame->tf_eax;
1198 if (p->p_sysent->sv_prepsyscall) {
1199 (*p->p_sysent->sv_prepsyscall)(
1200 frame, (int *)(&args.nosys.sysmsg + 1),
1204 * Need to check if this is a 32 bit or 64 bit syscall.
1205 * fuword is MP aware.
1207 if (code == SYS_syscall) {
1209 * Code is first argument, followed by actual args.
1211 code = fuword(params);
1212 params += sizeof(int);
1213 } else if (code == SYS___syscall) {
1215 * Like syscall, but code is a quad, so as to maintain
1216 * quad alignment for the rest of the arguments.
1218 code = fuword(params);
1219 params += sizeof(quad_t);
1223 code &= p->p_sysent->sv_mask;
1224 if (code >= p->p_sysent->sv_size)
1225 callp = &p->p_sysent->sv_table[0];
1227 callp = &p->p_sysent->sv_table[code];
1229 narg = callp->sy_narg & SYF_ARGMASK;
1232 * copyin is MP aware, but the tracing code is not
1234 if (narg && params) {
1235 error = copyin(params, (caddr_t)(&args.nosys.sysmsg + 1),
1236 narg * sizeof(register_t));
1239 if (KTRPOINT(td, KTR_SYSCALL)) {
1240 MAKEMPSAFE(have_mplock);
1242 ktrsyscall(lp, code, narg,
1243 (void *)(&args.nosys.sysmsg + 1));
1251 if (KTRPOINT(td, KTR_SYSCALL)) {
1252 MAKEMPSAFE(have_mplock);
1253 ktrsyscall(lp, code, narg, (void *)(&args.nosys.sysmsg + 1));
1258 * For traditional syscall code edx is left untouched when 32 bit
1259 * results are returned. Since edx is loaded from fds[1] when the
1260 * system call returns we pre-set it here.
1262 args.sysmsg_fds[0] = 0;
1263 args.sysmsg_fds[1] = frame->tf_edx;
1266 * The syscall might manipulate the trap frame. If it does it
1267 * will probably return EJUSTRETURN.
1269 args.sysmsg_frame = frame;
1271 STOPEVENT(p, S_SCE, narg); /* MP aware */
1274 * NOTE: All system calls run MPSAFE now. The system call itself
1275 * is responsible for getting the MP lock.
1277 error = (*callp->sy_call)(&args);
1280 kprintf("system call %d returned %d\n", code, error);
1285 * MP SAFE (we may or may not have the MP lock at this point)
1290 * Reinitialize proc pointer `p' as it may be different
1291 * if this is a child returning from fork syscall.
1294 lp = curthread->td_lwp;
1295 frame->tf_eax = args.sysmsg_fds[0];
1296 frame->tf_edx = args.sysmsg_fds[1];
1297 frame->tf_eflags &= ~PSL_C;
1301 * Reconstruct pc, assuming lcall $X,y is 7 bytes,
1302 * int 0x80 is 2 bytes. We saved this in tf_err.
1304 frame->tf_eip -= frame->tf_err;
1309 panic("Unexpected EASYNC return value (for now)");
1312 if (p->p_sysent->sv_errsize) {
1313 if (error >= p->p_sysent->sv_errsize)
1314 error = -1; /* XXX */
1316 error = p->p_sysent->sv_errtbl[error];
1318 frame->tf_eax = error;
1319 frame->tf_eflags |= PSL_C;
1324 * Traced syscall. trapsignal() is not MP aware.
1326 if ((orig_tf_eflags & PSL_T) /*&& !(orig_tf_eflags & PSL_VM)*/) {
1327 MAKEMPSAFE(have_mplock);
1328 frame->tf_eflags &= ~PSL_T;
1329 trapsignal(lp, SIGTRAP, TRAP_TRACE);
1333 * Handle reschedule and other end-of-syscall issues
1335 userret(lp, frame, sticks);
1338 if (KTRPOINT(td, KTR_SYSRET)) {
1339 MAKEMPSAFE(have_mplock);
1340 ktrsysret(lp, code, error, args.sysmsg_result);
1345 * This works because errno is findable through the
1346 * register set. If we ever support an emulation where this
1347 * is not the case, this code will need to be revisited.
1349 STOPEVENT(p, S_SCX, code);
1354 * Release the MP lock if we had to get it
1356 KASSERT(td->td_mpcount == have_mplock,
1357 ("badmpcount syscall2/end from %p", (void *)frame->tf_eip));
1361 KTR_LOG(kernentry_syscall_ret, lp->lwp_proc->p_pid, lp->lwp_tid, error);
1363 KASSERT(crit_count == (td->td_pri & ~TDPRI_MASK),
1364 ("syscall: critical section count mismatch! %d/%d",
1365 crit_count / TDPRI_CRIT, td->td_pri / TDPRI_CRIT));
1370 fork_return(struct lwp *lp, struct trapframe *frame)
1372 frame->tf_eax = 0; /* Child returns zero */
1373 frame->tf_eflags &= ~PSL_C; /* success */
1376 generic_lwp_return(lp, frame);
1377 KTR_LOG(kernentry_fork_ret, lp->lwp_proc->p_pid, lp->lwp_tid);
1381 * Simplified back end of syscall(), used when returning from fork()
1382 * or lwp_create() directly into user mode. MP lock is held on entry and
1383 * should be released on return. This code will return back into the fork
1384 * trampoline code which then runs doreti.
1387 generic_lwp_return(struct lwp *lp, struct trapframe *frame)
1389 struct proc *p = lp->lwp_proc;
1392 * Newly forked processes are given a kernel priority. We have to
1393 * adjust the priority to a normal user priority and fake entry
1394 * into the kernel (call userenter()) to install a passive release
1395 * function just in case userret() decides to stop the process. This
1396 * can occur when ^Z races a fork. If we do not install the passive
1397 * release function the current process designation will not be
1398 * released when the thread goes to sleep.
1400 lwkt_setpri_self(TDPRI_USER_NORM);
1401 userenter(lp->lwp_thread, p);
1402 userret(lp, frame, 0);
1404 if (KTRPOINT(lp->lwp_thread, KTR_SYSRET))
1405 ktrsysret(lp, SYS_fork, 0, 0);
1407 p->p_flag |= P_PASSIVE_ACQ;
1409 p->p_flag &= ~P_PASSIVE_ACQ;
1411 KKASSERT(lp->lwp_thread->td_mpcount == 1);
1417 * doreti has turned into this. The frame is directly on the stack. We
1418 * pull everything else we need (fpu and tls context) from the current
1421 * Note on fpu interactions: In a virtual kernel, the fpu context for
1422 * an emulated user mode process is not shared with the virtual kernel's
1423 * fpu context, so we only have to 'stack' fpu contexts within the virtual
1424 * kernel itself, and not even then since the signal() contexts that we care
1425 * about save and restore the FPU state (I think anyhow).
1427 * vmspace_ctl() returns an error only if it had problems instaling the
1428 * context we supplied or problems copying data to/from our VM space.
1431 go_user(struct intrframe *frame)
1433 struct trapframe *tf = (void *)&frame->if_gs;
1437 * Interrupts may be disabled on entry, make sure all signals
1438 * can be received before beginning our loop.
1443 * Switch to the current simulated user process, then call
1444 * user_trap() when we break out of it (usually due to a signal).
1448 * Tell the real kernel whether it is ok to use the FP
1451 * The critical section is required to prevent an interrupt
1452 * from causing a preemptive task switch and changing
1456 if (mdcpu->gd_npxthread == curthread) {
1457 tf->tf_xflags &= ~PGEX_FPFAULT;
1459 tf->tf_xflags |= PGEX_FPFAULT;
1463 * Run emulated user process context. This call interlocks
1464 * with new mailbox signals.
1466 * Set PGEX_U unconditionally, indicating a user frame (the
1467 * bit is normally set only by T_PAGEFLT).
1469 r = vmspace_ctl(&curproc->p_vmspace->vm_pmap, VMSPACE_CTL_RUN,
1470 tf, &curthread->td_savevext);
1472 frame->if_xflags |= PGEX_U;
1474 kprintf("GO USER %d trap %d EVA %08x EIP %08x ESP %08x XFLAGS %02x/%02x\n",
1475 r, tf->tf_trapno, tf->tf_err, tf->tf_eip, tf->tf_esp,
1476 tf->tf_xflags, frame->if_xflags);
1480 panic("vmspace_ctl failed");
1482 if (tf->tf_trapno) {
1486 if (mycpu->gd_reqflags & RQF_AST_MASK) {
1487 tf->tf_trapno = T_ASTFLT;
1495 * If PGEX_FPFAULT is set then set FP_VIRTFP in the PCB to force a T_DNA
1496 * fault (which is then passed back to the virtual kernel) if an attempt is
1497 * made to use the FP unit.
1499 * XXX this is a fairly big hack.
1502 set_vkernel_fp(struct trapframe *frame)
1504 struct thread *td = curthread;
1506 if (frame->tf_xflags & PGEX_FPFAULT) {
1507 td->td_pcb->pcb_flags |= FP_VIRTFP;
1508 if (mdcpu->gd_npxthread == td)
1511 td->td_pcb->pcb_flags &= ~FP_VIRTFP;