2 * Copyright (C) 1994, David Greenman
3 * Copyright (c) 1990, 1993
4 * The Regents of the University of California. All rights reserved.
6 * This code is derived from software contributed to Berkeley by
7 * the University of Utah, and William Jolitz.
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 * 3. All advertising materials mentioning features or use of this software
18 * must display the following acknowledgement:
19 * This product includes software developed by the University of
20 * California, Berkeley and its contributors.
21 * 4. Neither the name of the University nor the names of its contributors
22 * may be used to endorse or promote products derived from this software
23 * without specific prior written permission.
25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
28 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
37 * from: @(#)trap.c 7.4 (Berkeley) 5/13/91
38 * $FreeBSD: src/sys/i386/i386/trap.c,v 1.147.2.11 2003/02/27 19:09:59 luoqi Exp $
42 * x86_64 Trap and System call handling
48 #include "opt_ktrace.h"
50 #include <sys/param.h>
51 #include <sys/systm.h>
53 #include <sys/pioctl.h>
54 #include <sys/kernel.h>
55 #include <sys/resourcevar.h>
56 #include <sys/signalvar.h>
57 #include <sys/signal2.h>
58 #include <sys/syscall.h>
59 #include <sys/sysctl.h>
60 #include <sys/sysent.h>
62 #include <sys/vmmeter.h>
63 #include <sys/malloc.h>
65 #include <sys/ktrace.h>
68 #include <sys/upcall.h>
69 #include <sys/vkernel.h>
70 #include <sys/sysproto.h>
71 #include <sys/sysunion.h>
72 #include <sys/vmspace.h>
75 #include <vm/vm_param.h>
78 #include <vm/vm_kern.h>
79 #include <vm/vm_map.h>
80 #include <vm/vm_page.h>
81 #include <vm/vm_extern.h>
83 #include <machine/cpu.h>
84 #include <machine/md_var.h>
85 #include <machine/pcb.h>
86 #include <machine/smp.h>
87 #include <machine/tss.h>
88 #include <machine/globaldata.h>
92 #include <sys/msgport2.h>
93 #include <sys/thread2.h>
94 #include <sys/mplock2.h>
98 #define MAKEMPSAFE(have_mplock) \
99 if (have_mplock == 0) { \
106 #define MAKEMPSAFE(have_mplock)
110 int (*pmath_emulate) (struct trapframe *);
112 extern int trapwrite (unsigned addr);
114 static int trap_pfault (struct trapframe *, int, vm_offset_t);
115 static void trap_fatal (struct trapframe *, int, vm_offset_t);
116 void dblfault_handler (void);
119 extern inthand_t IDTVEC(syscall);
122 #define MAX_TRAP_MSG 30
123 static char *trap_msg[] = {
125 "privileged instruction fault", /* 1 T_PRIVINFLT */
127 "breakpoint instruction fault", /* 3 T_BPTFLT */
130 "arithmetic trap", /* 6 T_ARITHTRAP */
131 "system forced exception", /* 7 T_ASTFLT */
133 "general protection fault", /* 9 T_PROTFLT */
134 "trace trap", /* 10 T_TRCTRAP */
136 "page fault", /* 12 T_PAGEFLT */
138 "alignment fault", /* 14 T_ALIGNFLT */
142 "integer divide fault", /* 18 T_DIVIDE */
143 "non-maskable interrupt trap", /* 19 T_NMI */
144 "overflow trap", /* 20 T_OFLOW */
145 "FPU bounds check fault", /* 21 T_BOUND */
146 "FPU device not available", /* 22 T_DNA */
147 "double fault", /* 23 T_DOUBLEFLT */
148 "FPU operand fetch fault", /* 24 T_FPOPFLT */
149 "invalid TSS fault", /* 25 T_TSSFLT */
150 "segment not present fault", /* 26 T_SEGNPFLT */
151 "stack fault", /* 27 T_STKFLT */
152 "machine check trap", /* 28 T_MCHK */
153 "SIMD floating-point exception", /* 29 T_XMMFLT */
154 "reserved (unknown) fault", /* 30 T_RESERVED */
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 MALLOC_DEFINE(M_SYSMSG, "sysmsg", "sysmsg structure");
173 extern int max_sysmsg;
176 * Passively intercepts the thread switch function to increase the thread
177 * priority from a user priority to a kernel priority, reducing
178 * syscall and trap overhead for the case where no switch occurs.
180 * Synchronizes td_ucred with p_ucred. This is used by system calls,
181 * signal handling, faults, AST traps, and anything else that enters the
182 * kernel from userland and provides the kernel with a stable read-only
183 * copy of the process ucred.
186 userenter(struct thread *curtd, struct proc *curp)
191 curtd->td_release = lwkt_passive_release;
193 if (curtd->td_ucred != curp->p_ucred) {
194 ncred = crhold(curp->p_ucred);
195 ocred = curtd->td_ucred;
196 curtd->td_ucred = ncred;
203 * Handle signals, upcalls, profiling, and other AST's and/or tasks that
204 * must be completed before we can return to or try to return to userland.
206 * Note that td_sticks is a 64 bit quantity, but there's no point doing 64
207 * arithmatic on the delta calculation so the absolute tick values are
208 * truncated to an integer.
211 userret(struct lwp *lp, struct trapframe *frame, int sticks)
213 struct proc *p = lp->lwp_proc;
217 * Charge system time if profiling. Note: times are in microseconds.
218 * This may do a copyout and block, so do it first even though it
219 * means some system time will be charged as user time.
221 if (p->p_flags & P_PROFIL) {
222 addupc_task(p, frame->tf_rip,
223 (u_int)((int)lp->lwp_thread->td_sticks - sticks));
228 * If the jungle wants us dead, so be it.
230 if (lp->lwp_mpflags & LWP_MP_WEXIT) {
231 lwkt_gettoken(&p->p_token);
233 lwkt_reltoken(&p->p_token); /* NOT REACHED */
237 * Block here if we are in a stopped state.
239 if (p->p_stat == SSTOP) {
240 lwkt_gettoken(&p->p_token);
242 lwkt_reltoken(&p->p_token);
247 * Post any pending upcalls. If running a virtual kernel be sure
248 * to restore the virtual kernel's vmspace before posting the upcall.
250 if (p->p_flags & (P_SIGVTALRM | P_SIGPROF | P_UPCALLPEND)) {
251 lwkt_gettoken(&p->p_token);
252 if (p->p_flags & P_SIGVTALRM) {
253 p->p_flags &= ~P_SIGVTALRM;
254 ksignal(p, SIGVTALRM);
256 if (p->p_flags & P_SIGPROF) {
257 p->p_flags &= ~P_SIGPROF;
260 if (p->p_flags & P_UPCALLPEND) {
261 p->p_flags &= ~P_UPCALLPEND;
264 lwkt_reltoken(&p->p_token);
269 * Post any pending signals
271 * WARNING! postsig() can exit and not return.
273 if ((sig = CURSIG_TRACE(lp)) != 0) {
274 lwkt_gettoken(&p->p_token);
276 lwkt_reltoken(&p->p_token);
281 * block here if we are swapped out, but still process signals
282 * (such as SIGKILL). proc0 (the swapin scheduler) is already
283 * aware of our situation, we do not have to wake it up.
285 if (p->p_flags & P_SWAPPEDOUT) {
286 lwkt_gettoken(&p->p_token);
288 p->p_flags |= P_SWAPWAIT;
290 if (p->p_flags & P_SWAPWAIT)
291 tsleep(p, PCATCH, "SWOUT", 0);
292 p->p_flags &= ~P_SWAPWAIT;
294 lwkt_reltoken(&p->p_token);
299 * Make sure postsig() handled request to restore old signal mask after
300 * running signal handler.
302 KKASSERT((lp->lwp_flags & LWP_OLDMASK) == 0);
306 * Cleanup from userenter and any passive release that might have occured.
307 * We must reclaim the current-process designation before we can return
308 * to usermode. We also handle both LWKT and USER reschedule requests.
311 userexit(struct lwp *lp)
313 struct thread *td = lp->lwp_thread;
314 /* globaldata_t gd = td->td_gd; */
317 * Handle stop requests at kernel priority. Any requests queued
318 * after this loop will generate another AST.
320 while (lp->lwp_proc->p_stat == SSTOP) {
321 lwkt_gettoken(&lp->lwp_proc->p_token);
323 lwkt_reltoken(&lp->lwp_proc->p_token);
327 * Reduce our priority in preparation for a return to userland. If
328 * our passive release function was still in place, our priority was
329 * never raised and does not need to be reduced.
331 lwkt_passive_recover(td);
334 * Become the current user scheduled process if we aren't already,
335 * and deal with reschedule requests and other factors.
337 lp->lwp_proc->p_usched->acquire_curproc(lp);
338 /* WARNING: we may have migrated cpu's */
339 /* gd = td->td_gd; */
342 #if !defined(KTR_KERNENTRY)
343 #define KTR_KERNENTRY KTR_ALL
345 KTR_INFO_MASTER(kernentry);
346 KTR_INFO(KTR_KERNENTRY, kernentry, trap, 0,
347 "TRAP(pid %hd, tid %hd, trapno %ld, eva %lu)",
348 pid_t pid, lwpid_t tid, register_t trapno, vm_offset_t eva);
349 KTR_INFO(KTR_KERNENTRY, kernentry, trap_ret, 0, "TRAP_RET(pid %hd, tid %hd)",
350 pid_t pid, lwpid_t tid);
351 KTR_INFO(KTR_KERNENTRY, kernentry, syscall, 0, "SYSC(pid %hd, tid %hd, nr %ld)",
352 pid_t pid, lwpid_t tid, register_t trapno);
353 KTR_INFO(KTR_KERNENTRY, kernentry, syscall_ret, 0, "SYSRET(pid %hd, tid %hd, err %d)",
354 pid_t pid, lwpid_t tid, int err);
355 KTR_INFO(KTR_KERNENTRY, kernentry, fork_ret, 0, "FORKRET(pid %hd, tid %hd)",
356 pid_t pid, lwpid_t tid);
359 * Exception, fault, and trap interface to the kernel.
360 * This common code is called from assembly language IDT gate entry
361 * routines that prepare a suitable stack frame, and restore this
362 * frame after the exception has been processed.
364 * This function is also called from doreti in an interlock to handle ASTs.
365 * For example: hardwareint->INTROUTINE->(set ast)->doreti->trap
367 * NOTE! We have to retrieve the fault address prior to obtaining the
368 * MP lock because get_mplock() may switch out. YYY cr2 really ought
369 * to be retrieved by the assembly code, not here.
371 * XXX gd_trap_nesting_level currently prevents lwkt_switch() from panicing
372 * if an attempt is made to switch from a fast interrupt or IPI. This is
373 * necessary to properly take fatal kernel traps on SMP machines if
374 * get_mplock() has to block.
378 user_trap(struct trapframe *frame)
380 struct globaldata *gd = mycpu;
381 struct thread *td = gd->gd_curthread;
382 struct lwp *lp = td->td_lwp;
385 int i = 0, ucode = 0, type, code;
390 int crit_count = td->td_critcount;
391 lwkt_tokref_t curstop = td->td_toks_stop;
397 if (frame->tf_trapno == T_PAGEFLT)
398 eva = frame->tf_addr;
402 kprintf("USER_TRAP AT %08lx xflags %ld trapno %ld eva %08lx\n",
403 frame->tf_rip, frame->tf_xflags, frame->tf_trapno, eva);
407 * Everything coming from user mode runs through user_trap,
408 * including system calls.
410 if (frame->tf_trapno == T_FAST_SYSCALL) {
415 KTR_LOG(kernentry_trap, lp->lwp_proc->p_pid, lp->lwp_tid,
416 frame->tf_trapno, eva);
420 eva = (frame->tf_trapno == T_PAGEFLT ? rcr2() : 0);
421 ++gd->gd_trap_nesting_level;
422 MAKEMPSAFE(have_mplock);
423 trap_fatal(frame, TRUE, eva);
424 --gd->gd_trap_nesting_level;
429 type = frame->tf_trapno;
430 code = frame->tf_err;
434 sticks = (int)td->td_sticks;
435 lp->lwp_md.md_regs = frame;
438 case T_PRIVINFLT: /* privileged instruction fault */
443 case T_BPTFLT: /* bpt instruction fault */
444 case T_TRCTRAP: /* trace trap */
445 frame->tf_rflags &= ~PSL_T;
449 case T_ARITHTRAP: /* arithmetic trap */
454 case T_ASTFLT: /* Allow process switch */
455 mycpu->gd_cnt.v_soft++;
456 if (mycpu->gd_reqflags & RQF_AST_OWEUPC) {
457 atomic_clear_int(&mycpu->gd_reqflags, RQF_AST_OWEUPC);
458 addupc_task(p, p->p_prof.pr_addr, p->p_prof.pr_ticks);
463 * The following two traps can happen in
464 * vm86 mode, and, if so, we want to handle
467 case T_PROTFLT: /* general protection fault */
468 case T_STKFLT: /* stack fault */
470 if (frame->tf_eflags & PSL_VM) {
471 i = vm86_emulate((struct vm86frame *)frame);
479 case T_SEGNPFLT: /* segment not present fault */
480 case T_TSSFLT: /* invalid TSS fault */
481 case T_DOUBLEFLT: /* double fault */
483 ucode = code + BUS_SEGM_FAULT ;
487 case T_PAGEFLT: /* page fault */
488 MAKEMPSAFE(have_mplock);
489 i = trap_pfault(frame, TRUE, eva);
490 if (i == -1 || i == 0)
496 case T_DIVIDE: /* integer divide fault */
503 MAKEMPSAFE(have_mplock);
504 /* machine/parity/power fail/"kitchen sink" faults */
505 if (isa_nmi(code) == 0) {
508 * NMI can be hooked up to a pushbutton
512 kprintf ("NMI ... going to debugger\n");
513 kdb_trap (type, 0, frame);
517 } else if (panic_on_nmi)
518 panic("NMI indicates hardware failure");
520 #endif /* NISA > 0 */
522 case T_OFLOW: /* integer overflow fault */
527 case T_BOUND: /* bounds check fault */
534 * Virtual kernel intercept - pass the DNA exception
535 * to the (emulated) virtual kernel if it asked to handle
536 * it. This occurs when the virtual kernel is holding
537 * onto the FP context for a different emulated
538 * process then the one currently running.
540 * We must still call npxdna() since we may have
541 * saved FP state that the (emulated) virtual kernel
542 * needs to hand over to a different emulated process.
544 if (lp->lwp_vkernel && lp->lwp_vkernel->ve &&
545 (td->td_pcb->pcb_flags & FP_VIRTFP)
551 * The kernel may have switched out the FP unit's
552 * state, causing the user process to take a fault
553 * when it tries to use the FP unit. Restore the
558 if (!pmath_emulate) {
560 ucode = FPE_FPU_NP_TRAP;
563 i = (*pmath_emulate)(frame);
565 if (!(frame->tf_rflags & PSL_T))
567 frame->tf_rflags &= ~PSL_T;
570 /* else ucode = emulator_only_knows() XXX */
573 case T_FPOPFLT: /* FPU operand fetch fault */
578 case T_XMMFLT: /* SIMD floating-point exception */
585 * Virtual kernel intercept - if the fault is directly related to a
586 * VM context managed by a virtual kernel then let the virtual kernel
589 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) {
590 vkernel_trap(lp, frame);
595 * Translate fault for emulators (e.g. Linux)
597 if (*p->p_sysent->sv_transtrap)
598 i = (*p->p_sysent->sv_transtrap)(i, type);
600 MAKEMPSAFE(have_mplock);
601 trapsignal(lp, i, ucode);
604 if (type <= MAX_TRAP_MSG) {
605 uprintf("fatal process exception: %s",
607 if ((type == T_PAGEFLT) || (type == T_PROTFLT))
608 uprintf(", fault VA = 0x%lx", (u_long)eva);
614 userret(lp, frame, sticks);
621 KTR_LOG(kernentry_trap_ret, lp->lwp_proc->p_pid, lp->lwp_tid);
623 KASSERT(crit_count == td->td_critcount,
624 ("trap: critical section count mismatch! %d/%d",
625 crit_count, td->td_pri));
626 KASSERT(curstop == td->td_toks_stop,
627 ("trap: extra tokens held after trap! %ld/%ld",
628 curstop - &td->td_toks_base,
629 td->td_toks_stop - &td->td_toks_base));
634 kern_trap(struct trapframe *frame)
636 struct globaldata *gd = mycpu;
637 struct thread *td = gd->gd_curthread;
640 int i = 0, ucode = 0, type, code;
645 int crit_count = td->td_critcount;
646 lwkt_tokref_t curstop = td->td_toks_stop;
653 if (frame->tf_trapno == T_PAGEFLT)
654 eva = frame->tf_addr;
660 ++gd->gd_trap_nesting_level;
661 MAKEMPSAFE(have_mplock);
662 trap_fatal(frame, FALSE, eva);
663 --gd->gd_trap_nesting_level;
668 type = frame->tf_trapno;
669 code = frame->tf_err;
677 case T_PAGEFLT: /* page fault */
678 MAKEMPSAFE(have_mplock);
679 trap_pfault(frame, FALSE, eva);
684 * The kernel may be using npx for copying or other
687 panic("kernel NPX should not happen");
692 case T_PROTFLT: /* general protection fault */
693 case T_SEGNPFLT: /* segment not present fault */
695 * Invalid segment selectors and out of bounds
696 * %eip's and %esp's can be set up in user mode.
697 * This causes a fault in kernel mode when the
698 * kernel tries to return to user mode. We want
699 * to get this fault so that we can fix the
700 * problem here and not have to check all the
701 * selectors and pointers when the user changes
704 if (mycpu->gd_intr_nesting_level == 0) {
705 if (td->td_pcb->pcb_onfault) {
707 (register_t)td->td_pcb->pcb_onfault;
715 * PSL_NT can be set in user mode and isn't cleared
716 * automatically when the kernel is entered. This
717 * causes a TSS fault when the kernel attempts to
718 * `iret' because the TSS link is uninitialized. We
719 * want to get this fault so that we can fix the
720 * problem here and not every time the kernel is
723 if (frame->tf_rflags & PSL_NT) {
724 frame->tf_rflags &= ~PSL_NT;
729 case T_TRCTRAP: /* trace trap */
731 if (frame->tf_eip == (int)IDTVEC(syscall)) {
733 * We've just entered system mode via the
734 * syscall lcall. Continue single stepping
735 * silently until the syscall handler has
740 if (frame->tf_eip == (int)IDTVEC(syscall) + 1) {
742 * The syscall handler has now saved the
743 * flags. Stop single stepping it.
745 frame->tf_eflags &= ~PSL_T;
751 * Ignore debug register trace traps due to
752 * accesses in the user's address space, which
753 * can happen under several conditions such as
754 * if a user sets a watchpoint on a buffer and
755 * then passes that buffer to a system call.
756 * We still want to get TRCTRAPS for addresses
757 * in kernel space because that is useful when
758 * debugging the kernel.
760 if (user_dbreg_trap()) {
762 * Reset breakpoint bits because the
765 load_dr6(rdr6() & 0xfffffff0);
770 * Fall through (TRCTRAP kernel mode, kernel address)
774 * If DDB is enabled, let it handle the debugger trap.
775 * Otherwise, debugger traps "can't happen".
778 MAKEMPSAFE(have_mplock);
779 if (kdb_trap (type, 0, frame))
784 MAKEMPSAFE(have_mplock);
785 trap_fatal(frame, FALSE, eva);
788 MAKEMPSAFE(have_mplock);
789 trap_fatal(frame, FALSE, eva);
794 * Ignore this trap generated from a spurious SIGTRAP.
796 * single stepping in / syscalls leads to spurious / SIGTRAP
799 * Haiku (c) 2007 Simon 'corecode' Schubert
805 * Translate fault for emulators (e.g. Linux)
807 if (*p->p_sysent->sv_transtrap)
808 i = (*p->p_sysent->sv_transtrap)(i, type);
810 MAKEMPSAFE(have_mplock);
811 trapsignal(lp, i, ucode);
814 if (type <= MAX_TRAP_MSG) {
815 uprintf("fatal process exception: %s",
817 if ((type == T_PAGEFLT) || (type == T_PROTFLT))
818 uprintf(", fault VA = 0x%lx", (u_long)eva);
830 KASSERT(crit_count == td->td_critcount,
831 ("trap: critical section count mismatch! %d/%d",
832 crit_count, td->td_pri));
833 KASSERT(curstop == td->td_toks_stop,
834 ("trap: extra tokens held after trap! %ld/%ld",
835 curstop - &td->td_toks_base,
836 td->td_toks_stop - &td->td_toks_base));
841 trap_pfault(struct trapframe *frame, int usermode, vm_offset_t eva)
844 struct vmspace *vm = NULL;
848 thread_t td = curthread;
849 struct lwp *lp = td->td_lwp;
852 va = trunc_page(eva);
853 if (usermode == FALSE) {
855 * This is a fault on kernel virtual memory.
860 * This is a fault on non-kernel virtual memory.
861 * vm is initialized above to NULL. If curproc is NULL
862 * or curproc->p_vmspace is NULL the fault is fatal.
865 vm = lp->lwp_vmspace;
873 if (frame->tf_err & PGEX_W)
874 ftype = VM_PROT_READ | VM_PROT_WRITE;
876 ftype = VM_PROT_READ;
878 if (map != &kernel_map) {
880 * Keep swapout from messing with us during this
886 * Grow the stack if necessary
888 /* grow_stack returns false only if va falls into
889 * a growable stack region and the stack growth
890 * fails. It returns true if va was not within
891 * a growable stack region, or if the stack
894 if (!grow_stack (lp->lwp_proc, va)) {
902 fault_flags |= VM_FAULT_BURST;
903 if (ftype & VM_PROT_WRITE)
904 fault_flags |= VM_FAULT_DIRTY;
906 fault_flags |= VM_FAULT_NORMAL;
908 rv = vm_fault(map, va, ftype, fault_flags);
912 * Don't have to worry about process locking or stacks in the kernel.
914 rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL);
917 if (rv == KERN_SUCCESS)
921 if (td->td_gd->gd_intr_nesting_level == 0 &&
922 td->td_pcb->pcb_onfault) {
923 frame->tf_rip = (register_t)td->td_pcb->pcb_onfault;
926 trap_fatal(frame, usermode, eva);
931 * NOTE: on x86_64 we have a tf_addr field in the trapframe, no
932 * kludge is needed to pass the fault address to signal handlers.
934 struct proc *p = td->td_proc;
935 kprintf("seg-fault accessing address %p rip=%p pid=%d p_comm=%s\n",
936 (void *)va, (void *)frame->tf_rip, p->p_pid, p->p_comm);
937 /* Debugger("seg-fault"); */
939 return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV);
943 trap_fatal(struct trapframe *frame, int usermode, vm_offset_t eva)
948 code = frame->tf_xflags;
949 type = frame->tf_trapno;
951 if (type <= MAX_TRAP_MSG) {
952 kprintf("\n\nFatal trap %d: %s while in %s mode\n",
953 type, trap_msg[type],
954 (usermode ? "user" : "kernel"));
957 /* two separate prints in case of a trap on an unmapped page */
958 kprintf("cpuid = %d\n", mycpu->gd_cpuid);
960 if (type == T_PAGEFLT) {
961 kprintf("fault virtual address = %p\n", (void *)eva);
962 kprintf("fault code = %s %s, %s\n",
963 usermode ? "user" : "supervisor",
964 code & PGEX_W ? "write" : "read",
965 code & PGEX_P ? "protection violation" : "page not present");
967 kprintf("instruction pointer = 0x%lx:0x%lx\n",
968 frame->tf_cs & 0xffff, frame->tf_rip);
970 ss = frame->tf_ss & 0xffff;
973 ss = GSEL(GDATA_SEL, SEL_KPL);
974 rsp = (long)&frame->tf_rsp;
976 kprintf("stack pointer = 0x%x:0x%lx\n", ss, rsp);
977 kprintf("frame pointer = 0x%x:0x%lx\n", ss, frame->tf_rbp);
978 kprintf("processor eflags = ");
979 if (frame->tf_rflags & PSL_T)
980 kprintf("trace trap, ");
981 if (frame->tf_rflags & PSL_I)
982 kprintf("interrupt enabled, ");
983 if (frame->tf_rflags & PSL_NT)
984 kprintf("nested task, ");
985 if (frame->tf_rflags & PSL_RF)
988 if (frame->tf_eflags & PSL_VM)
991 kprintf("IOPL = %jd\n", (intmax_t)((frame->tf_rflags & PSL_IOPL) >> 12));
992 kprintf("current process = ");
994 kprintf("%lu (%s)\n",
995 (u_long)curproc->p_pid, curproc->p_comm ?
996 curproc->p_comm : "");
1000 kprintf("current thread = pri %d ", curthread->td_pri);
1001 if (curthread->td_critcount)
1007 * we probably SHOULD have stopped the other CPUs before now!
1008 * another CPU COULD have been touching cpl at this moment...
1010 kprintf(" <- SMP: XXX");
1019 if ((debugger_on_panic || db_active) && kdb_trap(type, code, frame))
1022 kprintf("trap number = %d\n", type);
1023 if (type <= MAX_TRAP_MSG)
1024 panic("%s", trap_msg[type]);
1026 panic("unknown/reserved trap");
1030 * Double fault handler. Called when a fault occurs while writing
1031 * a frame for a trap/exception onto the stack. This usually occurs
1032 * when the stack overflows (such is the case with infinite recursion,
1035 * XXX Note that the current PTD gets replaced by IdlePTD when the
1036 * task switch occurs. This means that the stack that was active at
1037 * the time of the double fault is not available at <kstack> unless
1038 * the machine was idle when the double fault occurred. The downside
1039 * of this is that "trace <ebp>" in ddb won't work.
1042 dblfault_handler(void)
1045 struct mdglobaldata *gd = mdcpu;
1048 kprintf("\nFatal double fault:\n");
1050 kprintf("rip = 0x%lx\n", gd->gd_common_tss.tss_rip);
1051 kprintf("rsp = 0x%lx\n", gd->gd_common_tss.tss_rsp);
1052 kprintf("rbp = 0x%lx\n", gd->gd_common_tss.tss_rbp);
1055 /* two separate prints in case of a trap on an unmapped page */
1056 kprintf("cpuid = %d\n", mycpu->gd_cpuid);
1058 panic("double fault");
1062 * Compensate for 386 brain damage (missing URKR).
1063 * This is a little simpler than the pagefault handler in trap() because
1064 * it the page tables have already been faulted in and high addresses
1065 * are thrown out early for other reasons.
1068 trapwrite(unsigned addr)
1075 va = trunc_page((vm_offset_t)addr);
1077 * XXX - MAX is END. Changed > to >= for temp. fix.
1079 if (va >= VM_MAX_USER_ADDRESS)
1082 lp = curthread->td_lwp;
1083 vm = lp->lwp_vmspace;
1085 PHOLD(lp->lwp_proc);
1087 if (!grow_stack (lp->lwp_proc, va)) {
1088 PRELE(lp->lwp_proc);
1093 * fault the data page
1095 rv = vm_fault(&vm->vm_map, va, VM_PROT_WRITE, VM_FAULT_DIRTY);
1097 PRELE(lp->lwp_proc);
1099 if (rv != KERN_SUCCESS)
1106 * syscall2 - MP aware system call request C handler
1108 * A system call is essentially treated as a trap except that the
1109 * MP lock is not held on entry or return. We are responsible for
1110 * obtaining the MP lock if necessary and for handling ASTs
1111 * (e.g. a task switch) prior to return.
1113 * In general, only simple access and manipulation of curproc and
1114 * the current stack is allowed without having to hold MP lock.
1116 * MPSAFE - note that large sections of this routine are run without
1120 syscall2(struct trapframe *frame)
1122 struct thread *td = curthread;
1123 struct proc *p = td->td_proc;
1124 struct lwp *lp = td->td_lwp;
1126 struct sysent *callp;
1127 register_t orig_tf_rflags;
1132 int crit_count = td->td_critcount;
1133 lwkt_tokref_t curstop = td->td_toks_stop;
1136 int have_mplock = 0;
1141 union sysunion args;
1142 register_t *argsdst;
1144 mycpu->gd_cnt.v_syscall++;
1146 KTR_LOG(kernentry_syscall, lp->lwp_proc->p_pid, lp->lwp_tid,
1149 userenter(td, p); /* lazy raise our priority */
1156 sticks = (int)td->td_sticks;
1157 orig_tf_rflags = frame->tf_rflags;
1160 * Virtual kernel intercept - if a VM context managed by a virtual
1161 * kernel issues a system call the virtual kernel handles it, not us.
1162 * Restore the virtual kernel context and return from its system
1163 * call. The current frame is copied out to the virtual kernel.
1165 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) {
1166 vkernel_trap(lp, frame);
1167 error = EJUSTRETURN;
1172 * Get the system call parameters and account for time
1174 lp->lwp_md.md_regs = frame;
1175 params = (caddr_t)frame->tf_rsp + sizeof(register_t);
1176 code = frame->tf_rax;
1178 if (p->p_sysent->sv_prepsyscall) {
1179 (*p->p_sysent->sv_prepsyscall)(
1180 frame, (int *)(&args.nosys.sysmsg + 1),
1183 if (code == SYS_syscall || code == SYS___syscall) {
1184 code = frame->tf_rdi;
1190 if (p->p_sysent->sv_mask)
1191 code &= p->p_sysent->sv_mask;
1193 if (code >= p->p_sysent->sv_size)
1194 callp = &p->p_sysent->sv_table[0];
1196 callp = &p->p_sysent->sv_table[code];
1198 narg = callp->sy_narg & SYF_ARGMASK;
1201 * On x86_64 we get up to six arguments in registers. The rest are
1202 * on the stack. The first six members of 'struct trapframe' happen
1203 * to be the registers used to pass arguments, in exactly the right
1206 argp = &frame->tf_rdi;
1208 argsdst = (register_t *)(&args.nosys.sysmsg + 1);
1210 * JG can we overflow the space pointed to by 'argsdst'
1211 * either with 'bcopy' or with 'copyin'?
1213 bcopy(argp, argsdst, sizeof(register_t) * regcnt);
1215 * copyin is MP aware, but the tracing code is not
1217 if (narg > regcnt) {
1218 KASSERT(params != NULL, ("copyin args with no params!"));
1219 error = copyin(params, &argsdst[regcnt],
1220 (narg - regcnt) * sizeof(register_t));
1223 if (KTRPOINT(td, KTR_SYSCALL)) {
1224 MAKEMPSAFE(have_mplock);
1226 ktrsyscall(lp, code, narg,
1227 (void *)(&args.nosys.sysmsg + 1));
1235 if (KTRPOINT(td, KTR_SYSCALL)) {
1236 MAKEMPSAFE(have_mplock);
1237 ktrsyscall(lp, code, narg, (void *)(&args.nosys.sysmsg + 1));
1242 * Default return value is 0 (will be copied to %rax). Double-value
1243 * returns use %rax and %rdx. %rdx is left unchanged for system
1244 * calls which return only one result.
1246 args.sysmsg_fds[0] = 0;
1247 args.sysmsg_fds[1] = frame->tf_rdx;
1250 * The syscall might manipulate the trap frame. If it does it
1251 * will probably return EJUSTRETURN.
1253 args.sysmsg_frame = frame;
1255 STOPEVENT(p, S_SCE, narg); /* MP aware */
1258 * NOTE: All system calls run MPSAFE now. The system call itself
1259 * is responsible for getting the MP lock.
1261 error = (*callp->sy_call)(&args);
1264 kprintf("system call %d returned %d\n", code, error);
1269 * MP SAFE (we may or may not have the MP lock at this point)
1274 * Reinitialize proc pointer `p' as it may be different
1275 * if this is a child returning from fork syscall.
1278 lp = curthread->td_lwp;
1279 frame->tf_rax = args.sysmsg_fds[0];
1280 frame->tf_rdx = args.sysmsg_fds[1];
1281 frame->tf_rflags &= ~PSL_C;
1285 * Reconstruct pc, we know that 'syscall' is 2 bytes.
1286 * We have to do a full context restore so that %r10
1287 * (which was holding the value of %rcx) is restored for
1288 * the next iteration.
1290 frame->tf_rip -= frame->tf_err;
1291 frame->tf_r10 = frame->tf_rcx;
1296 panic("Unexpected EASYNC return value (for now)");
1299 if (p->p_sysent->sv_errsize) {
1300 if (error >= p->p_sysent->sv_errsize)
1301 error = -1; /* XXX */
1303 error = p->p_sysent->sv_errtbl[error];
1305 frame->tf_rax = error;
1306 frame->tf_rflags |= PSL_C;
1311 * Traced syscall. trapsignal() is not MP aware.
1313 if (orig_tf_rflags & PSL_T) {
1314 MAKEMPSAFE(have_mplock);
1315 frame->tf_rflags &= ~PSL_T;
1316 trapsignal(lp, SIGTRAP, 0);
1320 * Handle reschedule and other end-of-syscall issues
1322 userret(lp, frame, sticks);
1325 if (KTRPOINT(td, KTR_SYSRET)) {
1326 MAKEMPSAFE(have_mplock);
1327 ktrsysret(lp, code, error, args.sysmsg_result);
1332 * This works because errno is findable through the
1333 * register set. If we ever support an emulation where this
1334 * is not the case, this code will need to be revisited.
1336 STOPEVENT(p, S_SCX, code);
1341 * Release the MP lock if we had to get it
1346 KTR_LOG(kernentry_syscall_ret, lp->lwp_proc->p_pid, lp->lwp_tid, error);
1348 KASSERT(&td->td_toks_base == td->td_toks_stop,
1349 ("syscall: critical section count mismatch! %d/%d",
1350 crit_count, td->td_pri));
1351 KASSERT(curstop == td->td_toks_stop,
1352 ("syscall: extra tokens held after trap! %ld",
1353 td->td_toks_stop - &td->td_toks_base));
1358 * NOTE: mplock not held at any point
1361 fork_return(struct lwp *lp, struct trapframe *frame)
1363 frame->tf_rax = 0; /* Child returns zero */
1364 frame->tf_rflags &= ~PSL_C; /* success */
1367 generic_lwp_return(lp, frame);
1368 KTR_LOG(kernentry_fork_ret, lp->lwp_proc->p_pid, lp->lwp_tid);
1372 * Simplified back end of syscall(), used when returning from fork()
1373 * directly into user mode.
1375 * This code will return back into the fork trampoline code which then
1378 * NOTE: The mplock is not held at any point.
1381 generic_lwp_return(struct lwp *lp, struct trapframe *frame)
1383 struct proc *p = lp->lwp_proc;
1386 * Newly forked processes are given a kernel priority. We have to
1387 * adjust the priority to a normal user priority and fake entry
1388 * into the kernel (call userenter()) to install a passive release
1389 * function just in case userret() decides to stop the process. This
1390 * can occur when ^Z races a fork. If we do not install the passive
1391 * release function the current process designation will not be
1392 * released when the thread goes to sleep.
1394 lwkt_setpri_self(TDPRI_USER_NORM);
1395 userenter(lp->lwp_thread, p);
1396 userret(lp, frame, 0);
1398 if (KTRPOINT(lp->lwp_thread, KTR_SYSRET))
1399 ktrsysret(lp, SYS_fork, 0, 0);
1401 lp->lwp_flags |= LWP_PASSIVE_ACQ;
1403 lp->lwp_flags &= ~LWP_PASSIVE_ACQ;
1407 * doreti has turned into this. The frame is directly on the stack. We
1408 * pull everything else we need (fpu and tls context) from the current
1411 * Note on fpu interactions: In a virtual kernel, the fpu context for
1412 * an emulated user mode process is not shared with the virtual kernel's
1413 * fpu context, so we only have to 'stack' fpu contexts within the virtual
1414 * kernel itself, and not even then since the signal() contexts that we care
1415 * about save and restore the FPU state (I think anyhow).
1417 * vmspace_ctl() returns an error only if it had problems instaling the
1418 * context we supplied or problems copying data to/from our VM space.
1421 go_user(struct intrframe *frame)
1423 struct trapframe *tf = (void *)&frame->if_rdi;
1427 * Interrupts may be disabled on entry, make sure all signals
1428 * can be received before beginning our loop.
1433 * Switch to the current simulated user process, then call
1434 * user_trap() when we break out of it (usually due to a signal).
1438 * Tell the real kernel whether it is ok to use the FP
1441 if (mdcpu->gd_npxthread == curthread) {
1442 tf->tf_xflags &= ~PGEX_FPFAULT;
1444 tf->tf_xflags |= PGEX_FPFAULT;
1448 * Run emulated user process context. This call interlocks
1449 * with new mailbox signals.
1451 * Set PGEX_U unconditionally, indicating a user frame (the
1452 * bit is normally set only by T_PAGEFLT).
1454 r = vmspace_ctl(&curproc->p_vmspace->vm_pmap, VMSPACE_CTL_RUN,
1455 tf, &curthread->td_savevext);
1456 frame->if_xflags |= PGEX_U;
1458 kprintf("GO USER %d trap %ld EVA %08lx RIP %08lx RSP %08lx XFLAGS %02lx/%02lx\n",
1459 r, tf->tf_trapno, tf->tf_addr, tf->tf_rip, tf->tf_rsp,
1460 tf->tf_xflags, frame->if_xflags);
1464 panic("vmspace_ctl failed error %d", errno);
1466 if (tf->tf_trapno) {
1470 if (mycpu->gd_reqflags & RQF_AST_MASK) {
1471 tf->tf_trapno = T_ASTFLT;
1479 * If PGEX_FPFAULT is set then set FP_VIRTFP in the PCB to force a T_DNA
1480 * fault (which is then passed back to the virtual kernel) if an attempt is
1481 * made to use the FP unit.
1483 * XXX this is a fairly big hack.
1486 set_vkernel_fp(struct trapframe *frame)
1488 struct thread *td = curthread;
1490 if (frame->tf_xflags & PGEX_FPFAULT) {
1491 td->td_pcb->pcb_flags |= FP_VIRTFP;
1492 if (mdcpu->gd_npxthread == td)
1495 td->td_pcb->pcb_flags &= ~FP_VIRTFP;
1500 * Called from vkernel_trap() to fixup the vkernel's syscall
1501 * frame for vmspace_ctl() return.
1504 cpu_vkernel_trap(struct trapframe *frame, int error)
1506 frame->tf_rax = error;
1508 frame->tf_rflags |= PSL_C;
1510 frame->tf_rflags &= ~PSL_C;