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
40 #include <sys/cdefs.h>
41 __FBSDID("$FreeBSD$");
44 * 386 Trap and System call handling
47 #include "opt_clock.h"
49 #include "opt_hwpmc_hooks.h"
53 #include "opt_stack.h"
56 #include <sys/param.h>
58 #include <sys/systm.h>
60 #include <sys/pioctl.h>
61 #include <sys/ptrace.h>
63 #include <sys/kernel.h>
66 #include <sys/mutex.h>
67 #include <sys/resourcevar.h>
68 #include <sys/signalvar.h>
69 #include <sys/syscall.h>
70 #include <sys/sysctl.h>
71 #include <sys/sysent.h>
73 #include <sys/vmmeter.h>
75 #include <sys/pmckern.h>
76 PMC_SOFT_DEFINE( , , page_fault, all);
77 PMC_SOFT_DEFINE( , , page_fault, read);
78 PMC_SOFT_DEFINE( , , page_fault, write);
80 #include <security/audit/audit.h>
83 #include <vm/vm_param.h>
85 #include <vm/vm_kern.h>
86 #include <vm/vm_map.h>
87 #include <vm/vm_page.h>
88 #include <vm/vm_extern.h>
90 #include <machine/cpu.h>
91 #include <machine/intr_machdep.h>
93 #include <machine/md_var.h>
94 #include <machine/pcb.h>
96 #include <machine/smp.h>
98 #include <machine/stack.h>
99 #include <machine/tss.h>
100 #include <machine/vm86.h>
103 #include <sys/syslog.h>
104 #include <machine/clock.h>
108 #include <sys/dtrace_bsd.h>
111 extern void trap(struct trapframe *frame);
112 extern void syscall(struct trapframe *frame);
114 static int trap_pfault(struct trapframe *, int, vm_offset_t);
115 static void trap_fatal(struct trapframe *, vm_offset_t);
116 void dblfault_handler(void);
118 extern inthand_t IDTVEC(lcall_syscall);
120 #define MAX_TRAP_MSG 32
121 static char *trap_msg[] = {
123 "privileged instruction fault", /* 1 T_PRIVINFLT */
125 "breakpoint instruction fault", /* 3 T_BPTFLT */
128 "arithmetic trap", /* 6 T_ARITHTRAP */
131 "general protection fault", /* 9 T_PROTFLT */
132 "trace trap", /* 10 T_TRCTRAP */
134 "page fault", /* 12 T_PAGEFLT */
136 "alignment fault", /* 14 T_ALIGNFLT */
140 "integer divide fault", /* 18 T_DIVIDE */
141 "non-maskable interrupt trap", /* 19 T_NMI */
142 "overflow trap", /* 20 T_OFLOW */
143 "FPU bounds check fault", /* 21 T_BOUND */
144 "FPU device not available", /* 22 T_DNA */
145 "double fault", /* 23 T_DOUBLEFLT */
146 "FPU operand fetch fault", /* 24 T_FPOPFLT */
147 "invalid TSS fault", /* 25 T_TSSFLT */
148 "segment not present fault", /* 26 T_SEGNPFLT */
149 "stack fault", /* 27 T_STKFLT */
150 "machine check trap", /* 28 T_MCHK */
151 "SIMD floating-point exception", /* 29 T_XMMFLT */
152 "reserved (unknown) fault", /* 30 T_RESERVED */
153 "", /* 31 unused (reserved) */
154 "DTrace pid return trap", /* 32 T_DTRACE_RET */
157 #if defined(I586_CPU) && !defined(NO_F00F_HACK)
158 int has_f00f_bug = 0; /* Initialized so that it can be patched. */
161 static int prot_fault_translation = 0;
162 SYSCTL_INT(_machdep, OID_AUTO, prot_fault_translation, CTLFLAG_RW,
163 &prot_fault_translation, 0, "Select signal to deliver on protection fault");
164 static int uprintf_signal;
165 SYSCTL_INT(_machdep, OID_AUTO, uprintf_signal, CTLFLAG_RW,
167 "Print debugging information on trap signal to ctty");
170 * Exception, fault, and trap interface to the FreeBSD kernel.
171 * This common code is called from assembly language IDT gate entry
172 * routines that prepare a suitable stack frame, and restore this
173 * frame after the exception has been processed.
177 trap(struct trapframe *frame)
182 struct thread *td = curthread;
183 struct proc *p = td->td_proc;
187 int i = 0, ucode = 0;
193 static int lastalert = 0;
196 PCPU_INC(cnt.v_trap);
197 type = frame->tf_trapno;
200 /* Handler for NMI IPIs used for stopping CPUs. */
202 if (ipi_nmi_handler() == 0)
214 if (type == T_RESERVED) {
215 trap_fatal(frame, 0);
222 * CPU PMCs interrupt using an NMI so we check for that first.
223 * If the HWPMC module is active, 'pmc_hook' will point to
224 * the function to be called. A non-zero return value from the
225 * hook means that the NMI was consumed by it and that we can
226 * return immediately.
228 if (pmc_intr != NULL &&
229 (*pmc_intr)(PCPU_GET(cpuid), frame) != 0)
234 if (stack_nmi_handler(frame) != 0)
239 if (type == T_MCHK) {
246 * A trap can occur while DTrace executes a probe. Before
247 * executing the probe, DTrace blocks re-scheduling and sets
248 * a flag in its per-cpu flags to indicate that it doesn't
249 * want to fault. On returning from the probe, the no-fault
250 * flag is cleared and finally re-scheduling is enabled.
252 if ((type == T_PROTFLT || type == T_PAGEFLT) &&
253 dtrace_trap_func != NULL && (*dtrace_trap_func)(frame, type))
257 if ((frame->tf_eflags & PSL_I) == 0) {
259 * Buggy application or kernel code has disabled
260 * interrupts and then trapped. Enabling interrupts
261 * now is wrong, but it is better than running with
262 * interrupts disabled until they are accidentally
265 if (TRAPF_USERMODE(frame) &&
266 (curpcb->pcb_flags & PCB_VM86CALL) == 0)
268 "pid %ld (%s): trap %d with interrupts disabled\n",
269 (long)curproc->p_pid, curthread->td_name, type);
270 else if (type != T_NMI && type != T_BPTFLT &&
272 frame->tf_eip != (int)cpu_switch_load_gs) {
274 * XXX not quite right, since this may be for a
275 * multiple fault in user mode.
277 printf("kernel trap %d with interrupts disabled\n",
280 * Page faults need interrupts disabled until later,
281 * and we shouldn't enable interrupts while holding
284 if (type != T_PAGEFLT &&
285 td->td_md.md_spinlock_count == 0)
290 if (type == T_PAGEFLT) {
292 * For some Cyrix CPUs, %cr2 is clobbered by
293 * interrupts. This problem is worked around by using
294 * an interrupt gate for the pagefault handler. We
295 * are finally ready to read %cr2 and conditionally
296 * reenable interrupts. If we hold a spin lock, then
297 * we must not reenable interrupts. This might be a
298 * spurious page fault.
301 if (td->td_md.md_spinlock_count == 0)
305 if (TRAPF_USERMODE(frame) && (curpcb->pcb_flags & PCB_VM86CALL) == 0) {
309 td->td_frame = frame;
310 addr = frame->tf_eip;
311 if (td->td_cowgen != p->p_cowgen)
312 thread_cow_update(td);
315 case T_PRIVINFLT: /* privileged instruction fault */
320 case T_BPTFLT: /* bpt instruction fault */
321 case T_TRCTRAP: /* trace trap */
324 if (type == T_BPTFLT) {
325 fill_frame_regs(frame, ®s);
326 if (dtrace_pid_probe_ptr != NULL &&
327 dtrace_pid_probe_ptr(®s) == 0)
332 frame->tf_eflags &= ~PSL_T;
334 ucode = (type == T_TRCTRAP ? TRAP_TRACE : TRAP_BRKPT);
337 case T_ARITHTRAP: /* arithmetic trap */
339 ucode = npxtrap_x87();
349 * The following two traps can happen in
350 * vm86 mode, and, if so, we want to handle
353 case T_PROTFLT: /* general protection fault */
354 case T_STKFLT: /* stack fault */
355 if (frame->tf_eflags & PSL_VM) {
356 i = vm86_emulate((struct vm86frame *)frame);
359 load_dr6(rdr6() | 0x4000);
360 goto user_trctrap_out;
367 ucode = (type == T_PROTFLT) ? BUS_OBJERR : BUS_ADRERR;
369 case T_SEGNPFLT: /* segment not present fault */
373 case T_TSSFLT: /* invalid TSS fault */
381 case T_DOUBLEFLT: /* double fault */
387 case T_PAGEFLT: /* page fault */
389 i = trap_pfault(frame, TRUE, eva);
390 #if defined(I586_CPU) && !defined(NO_F00F_HACK)
393 * The f00f hack workaround has triggered, so
394 * treat the fault as an illegal instruction
395 * (T_PRIVINFLT) instead of a page fault.
397 type = frame->tf_trapno = T_PRIVINFLT;
399 /* Proceed as in that case. */
413 if (prot_fault_translation == 0) {
416 * This check also covers the images
417 * without the ABI-tag ELF note.
419 if (SV_CURPROC_ABI() == SV_ABI_FREEBSD
420 && p->p_osrel >= P_OSREL_SIGSEGV) {
425 ucode = BUS_PAGE_FAULT;
427 } else if (prot_fault_translation == 1) {
429 * Always compat mode.
432 ucode = BUS_PAGE_FAULT;
435 * Always SIGSEGV mode.
444 case T_DIVIDE: /* integer divide fault */
453 # define TIMER_FREQ 1193182
455 if (time_second - lastalert > 10) {
456 log(LOG_WARNING, "NMI: power fail\n");
458 lastalert = time_second;
461 #else /* !POWERFAIL_NMI */
462 nmi_handle_intr(type, frame);
464 #endif /* POWERFAIL_NMI */
467 case T_OFLOW: /* integer overflow fault */
472 case T_BOUND: /* bounds check fault */
479 KASSERT(PCB_USER_FPU(td->td_pcb),
480 ("kernel FPU ctx has leaked"));
481 /* transparent fault (due to context switch "late") */
485 uprintf("pid %d killed due to lack of floating point\n",
491 case T_FPOPFLT: /* FPU operand fetch fault */
496 case T_XMMFLT: /* SIMD floating-point exception */
497 #if defined(DEV_NPX) && !defined(CPU_DISABLE_SSE) && defined(I686_CPU)
498 ucode = npxtrap_sse();
509 fill_frame_regs(frame, ®s);
510 if (dtrace_return_probe_ptr != NULL &&
511 dtrace_return_probe_ptr(®s) == 0)
519 KASSERT(cold || td->td_ucred != NULL,
520 ("kernel trap doesn't have ucred"));
522 case T_PAGEFLT: /* page fault */
523 (void) trap_pfault(frame, FALSE, eva);
528 if (PCB_USER_FPU(td->td_pcb))
529 panic("Unregistered use of FPU in kernel");
535 case T_ARITHTRAP: /* arithmetic trap */
536 case T_XMMFLT: /* SIMD floating-point exception */
537 case T_FPOPFLT: /* FPU operand fetch fault */
539 * XXXKIB for now disable any FPU traps in kernel
540 * handler registration seems to be overkill
542 trap_fatal(frame, 0);
546 * The following two traps can happen in
547 * vm86 mode, and, if so, we want to handle
550 case T_PROTFLT: /* general protection fault */
551 case T_STKFLT: /* stack fault */
552 if (frame->tf_eflags & PSL_VM) {
553 i = vm86_emulate((struct vm86frame *)frame);
556 load_dr6(rdr6() | 0x4000);
561 * returns to original process
563 vm86_trap((struct vm86frame *)frame);
566 if (type == T_STKFLT)
571 case T_SEGNPFLT: /* segment not present fault */
572 if (curpcb->pcb_flags & PCB_VM86CALL)
576 * Invalid %fs's and %gs's can be created using
577 * procfs or PT_SETREGS or by invalidating the
578 * underlying LDT entry. This causes a fault
579 * in kernel mode when the kernel attempts to
580 * switch contexts. Lose the bad context
581 * (XXX) so that we can continue, and generate
584 if (frame->tf_eip == (int)cpu_switch_load_gs) {
588 kern_psignal(p, SIGBUS);
594 if (td->td_intr_nesting_level != 0)
598 * Invalid segment selectors and out of bounds
599 * %eip's and %esp's can be set up in user mode.
600 * This causes a fault in kernel mode when the
601 * kernel tries to return to user mode. We want
602 * to get this fault so that we can fix the
603 * problem here and not have to check all the
604 * selectors and pointers when the user changes
607 if (frame->tf_eip == (int)doreti_iret) {
608 frame->tf_eip = (int)doreti_iret_fault;
611 if (frame->tf_eip == (int)doreti_popl_ds) {
612 frame->tf_eip = (int)doreti_popl_ds_fault;
615 if (frame->tf_eip == (int)doreti_popl_es) {
616 frame->tf_eip = (int)doreti_popl_es_fault;
619 if (frame->tf_eip == (int)doreti_popl_fs) {
620 frame->tf_eip = (int)doreti_popl_fs_fault;
623 if (curpcb->pcb_onfault != NULL) {
625 (int)curpcb->pcb_onfault;
632 * PSL_NT can be set in user mode and isn't cleared
633 * automatically when the kernel is entered. This
634 * causes a TSS fault when the kernel attempts to
635 * `iret' because the TSS link is uninitialized. We
636 * want to get this fault so that we can fix the
637 * problem here and not every time the kernel is
640 if (frame->tf_eflags & PSL_NT) {
641 frame->tf_eflags &= ~PSL_NT;
646 case T_TRCTRAP: /* trace trap */
648 if (frame->tf_eip == (int)IDTVEC(lcall_syscall)) {
650 * We've just entered system mode via the
651 * syscall lcall. Continue single stepping
652 * silently until the syscall handler has
657 if (frame->tf_eip == (int)IDTVEC(lcall_syscall) + 1) {
659 * The syscall handler has now saved the
660 * flags. Stop single stepping it.
662 frame->tf_eflags &= ~PSL_T;
666 * Ignore debug register trace traps due to
667 * accesses in the user's address space, which
668 * can happen under several conditions such as
669 * if a user sets a watchpoint on a buffer and
670 * then passes that buffer to a system call.
671 * We still want to get TRCTRAPS for addresses
672 * in kernel space because that is useful when
673 * debugging the kernel.
675 if (user_dbreg_trap() &&
676 !(curpcb->pcb_flags & PCB_VM86CALL)) {
678 * Reset breakpoint bits because the
681 load_dr6(rdr6() & ~0xf);
685 * FALLTHROUGH (TRCTRAP kernel mode, kernel address)
689 * If KDB is enabled, let it handle the debugger trap.
690 * Otherwise, debugger traps "can't happen".
693 /* XXX %dr6 is not quite reentrant. */
695 load_dr6(dr6 & ~0x4000);
696 if (kdb_trap(type, dr6, frame))
704 if (time_second - lastalert > 10) {
705 log(LOG_WARNING, "NMI: power fail\n");
707 lastalert = time_second;
710 #else /* !POWERFAIL_NMI */
711 nmi_handle_intr(type, frame);
713 #endif /* POWERFAIL_NMI */
717 trap_fatal(frame, eva);
721 /* Translate fault for emulators (e.g. Linux) */
722 if (*p->p_sysent->sv_transtrap)
723 i = (*p->p_sysent->sv_transtrap)(i, type);
725 ksiginfo_init_trap(&ksi);
727 ksi.ksi_code = ucode;
728 ksi.ksi_addr = (void *)addr;
729 ksi.ksi_trapno = type;
730 if (uprintf_signal) {
731 uprintf("pid %d comm %s: signal %d err %x code %d type %d "
732 "addr 0x%x esp 0x%08x eip 0x%08x "
733 "<%02x %02x %02x %02x %02x %02x %02x %02x>\n",
734 p->p_pid, p->p_comm, i, frame->tf_err, ucode, type, addr,
735 frame->tf_esp, frame->tf_eip,
736 fubyte((void *)(frame->tf_eip + 0)),
737 fubyte((void *)(frame->tf_eip + 1)),
738 fubyte((void *)(frame->tf_eip + 2)),
739 fubyte((void *)(frame->tf_eip + 3)),
740 fubyte((void *)(frame->tf_eip + 4)),
741 fubyte((void *)(frame->tf_eip + 5)),
742 fubyte((void *)(frame->tf_eip + 6)),
743 fubyte((void *)(frame->tf_eip + 7)));
745 KASSERT((read_eflags() & PSL_I) != 0, ("interrupts disabled"));
746 trapsignal(td, &ksi);
749 if (type <= MAX_TRAP_MSG) {
750 uprintf("fatal process exception: %s",
752 if ((type == T_PAGEFLT) || (type == T_PROTFLT))
753 uprintf(", fault VA = 0x%lx", (u_long)eva);
760 KASSERT(PCB_USER_FPU(td->td_pcb),
761 ("Return from trap with kernel FPU ctx leaked"));
768 trap_pfault(frame, usermode, eva)
769 struct trapframe *frame;
777 struct thread *td = curthread;
778 struct proc *p = td->td_proc;
780 if (__predict_false((td->td_pflags & TDP_NOFAULTING) != 0)) {
782 * Due to both processor errata and lazy TLB invalidation when
783 * access restrictions are removed from virtual pages, memory
784 * accesses that are allowed by the physical mapping layer may
785 * nonetheless cause one spurious page fault per virtual page.
786 * When the thread is executing a "no faulting" section that
787 * is bracketed by vm_fault_{disable,enable}_pagefaults(),
788 * every page fault is treated as a spurious page fault,
789 * unless it accesses the same virtual address as the most
790 * recent page fault within the same "no faulting" section.
792 if (td->td_md.md_spurflt_addr != eva ||
793 (td->td_pflags & TDP_RESETSPUR) != 0) {
795 * Do nothing to the TLB. A stale TLB entry is
796 * flushed automatically by a page fault.
798 td->td_md.md_spurflt_addr = eva;
799 td->td_pflags &= ~TDP_RESETSPUR;
804 * If we get a page fault while in a critical section, then
805 * it is most likely a fatal kernel page fault. The kernel
806 * is already going to panic trying to get a sleep lock to
807 * do the VM lookup, so just consider it a fatal trap so the
808 * kernel can print out a useful trap message and even get
811 * If we get a page fault while holding a non-sleepable
812 * lock, then it is most likely a fatal kernel page fault.
813 * If WITNESS is enabled, then it's going to whine about
814 * bogus LORs with various VM locks, so just skip to the
815 * fatal trap handling directly.
817 if (td->td_critnest != 0 ||
818 WITNESS_CHECK(WARN_SLEEPOK | WARN_GIANTOK, NULL,
819 "Kernel page fault") != 0) {
820 trap_fatal(frame, eva);
824 va = trunc_page(eva);
825 if (va >= KERNBASE) {
827 * Don't allow user-mode faults in kernel address space.
828 * An exception: if the faulting address is the invalid
829 * instruction entry in the IDT, then the Intel Pentium
830 * F00F bug workaround was triggered, and we need to
831 * treat it is as an illegal instruction, and not a page
834 #if defined(I586_CPU) && !defined(NO_F00F_HACK)
835 if ((eva == (unsigned int)&idt[6]) && has_f00f_bug)
843 map = &p->p_vmspace->vm_map;
846 * When accessing a user-space address, kernel must be
847 * ready to accept the page fault, and provide a
848 * handling routine. Since accessing the address
849 * without the handler is a bug, do not try to handle
850 * it normally, and panic immediately.
852 if (!usermode && (td->td_intr_nesting_level != 0 ||
853 curpcb->pcb_onfault == NULL)) {
854 trap_fatal(frame, eva);
860 * If the trap was caused by errant bits in the PTE then panic.
862 if (frame->tf_err & PGEX_RSV) {
863 trap_fatal(frame, eva);
868 * PGEX_I is defined only if the execute disable bit capability is
869 * supported and enabled.
871 if (frame->tf_err & PGEX_W)
872 ftype = VM_PROT_WRITE;
873 #if defined(PAE) || defined(PAE_TABLES)
874 else if ((frame->tf_err & PGEX_I) && pg_nx != 0)
875 ftype = VM_PROT_EXECUTE;
878 ftype = VM_PROT_READ;
880 /* Fault in the page. */
881 rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL);
882 if (rv == KERN_SUCCESS) {
884 if (ftype == VM_PROT_READ || ftype == VM_PROT_WRITE) {
885 PMC_SOFT_CALL_TF( , , page_fault, all, frame);
886 if (ftype == VM_PROT_READ)
887 PMC_SOFT_CALL_TF( , , page_fault, read,
890 PMC_SOFT_CALL_TF( , , page_fault, write,
898 if (td->td_intr_nesting_level == 0 &&
899 curpcb->pcb_onfault != NULL) {
900 frame->tf_eip = (int)curpcb->pcb_onfault;
903 trap_fatal(frame, eva);
906 return ((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV);
910 trap_fatal(frame, eva)
911 struct trapframe *frame;
916 struct soft_segment_descriptor softseg;
919 code = frame->tf_err;
920 type = frame->tf_trapno;
921 sdtossd(&gdt[IDXSEL(frame->tf_cs & 0xffff)].sd, &softseg);
923 if (type <= MAX_TRAP_MSG)
924 msg = trap_msg[type];
927 printf("\n\nFatal trap %d: %s while in %s mode\n", type, msg,
928 frame->tf_eflags & PSL_VM ? "vm86" :
929 ISPL(frame->tf_cs) == SEL_UPL ? "user" : "kernel");
931 /* two separate prints in case of a trap on an unmapped page */
932 printf("cpuid = %d; ", PCPU_GET(cpuid));
933 printf("apic id = %02x\n", PCPU_GET(apic_id));
935 if (type == T_PAGEFLT) {
936 printf("fault virtual address = 0x%x\n", eva);
937 printf("fault code = %s %s%s, %s\n",
938 code & PGEX_U ? "user" : "supervisor",
939 code & PGEX_W ? "write" : "read",
940 #if defined(PAE) || defined(PAE_TABLES)
942 (code & PGEX_I ? " instruction" : " data") :
945 code & PGEX_RSV ? "reserved bits in PTE" :
946 code & PGEX_P ? "protection violation" : "page not present");
948 printf("instruction pointer = 0x%x:0x%x\n",
949 frame->tf_cs & 0xffff, frame->tf_eip);
950 if (TF_HAS_STACKREGS(frame)) {
951 ss = frame->tf_ss & 0xffff;
954 ss = GSEL(GDATA_SEL, SEL_KPL);
955 esp = (int)&frame->tf_esp;
957 printf("stack pointer = 0x%x:0x%x\n", ss, esp);
958 printf("frame pointer = 0x%x:0x%x\n", ss, frame->tf_ebp);
959 printf("code segment = base 0x%x, limit 0x%x, type 0x%x\n",
960 softseg.ssd_base, softseg.ssd_limit, softseg.ssd_type);
961 printf(" = DPL %d, pres %d, def32 %d, gran %d\n",
962 softseg.ssd_dpl, softseg.ssd_p, softseg.ssd_def32,
964 printf("processor eflags = ");
965 if (frame->tf_eflags & PSL_T)
966 printf("trace trap, ");
967 if (frame->tf_eflags & PSL_I)
968 printf("interrupt enabled, ");
969 if (frame->tf_eflags & PSL_NT)
970 printf("nested task, ");
971 if (frame->tf_eflags & PSL_RF)
973 if (frame->tf_eflags & PSL_VM)
975 printf("IOPL = %d\n", (frame->tf_eflags & PSL_IOPL) >> 12);
976 printf("current process = %d (%s)\n",
977 curproc->p_pid, curthread->td_name);
980 if (debugger_on_panic || kdb_active) {
981 frame->tf_err = eva; /* smuggle fault address to ddb */
982 if (kdb_trap(type, 0, frame)) {
983 frame->tf_err = code; /* restore error code */
986 frame->tf_err = code; /* restore error code */
989 printf("trap number = %d\n", type);
990 if (type <= MAX_TRAP_MSG)
991 panic("%s", trap_msg[type]);
993 panic("unknown/reserved trap");
997 * Double fault handler. Called when a fault occurs while writing
998 * a frame for a trap/exception onto the stack. This usually occurs
999 * when the stack overflows (such is the case with infinite recursion,
1002 * XXX Note that the current PTD gets replaced by IdlePTD when the
1003 * task switch occurs. This means that the stack that was active at
1004 * the time of the double fault is not available at <kstack> unless
1005 * the machine was idle when the double fault occurred. The downside
1006 * of this is that "trace <ebp>" in ddb won't work.
1011 #ifdef KDTRACE_HOOKS
1012 if (dtrace_doubletrap_func != NULL)
1013 (*dtrace_doubletrap_func)();
1015 printf("\nFatal double fault:\n");
1016 printf("eip = 0x%x\n", PCPU_GET(common_tss.tss_eip));
1017 printf("esp = 0x%x\n", PCPU_GET(common_tss.tss_esp));
1018 printf("ebp = 0x%x\n", PCPU_GET(common_tss.tss_ebp));
1020 /* two separate prints in case of a trap on an unmapped page */
1021 printf("cpuid = %d; ", PCPU_GET(cpuid));
1022 printf("apic id = %02x\n", PCPU_GET(apic_id));
1024 panic("double fault");
1028 cpu_fetch_syscall_args(struct thread *td, struct syscall_args *sa)
1031 struct trapframe *frame;
1037 frame = td->td_frame;
1039 params = (caddr_t)frame->tf_esp + sizeof(int);
1040 sa->code = frame->tf_eax;
1043 * Need to check if this is a 32 bit or 64 bit syscall.
1045 if (sa->code == SYS_syscall) {
1047 * Code is first argument, followed by actual args.
1049 error = fueword(params, &tmp);
1053 params += sizeof(int);
1054 } else if (sa->code == SYS___syscall) {
1056 * Like syscall, but code is a quad, so as to maintain
1057 * quad alignment for the rest of the arguments.
1059 error = fueword(params, &tmp);
1063 params += sizeof(quad_t);
1066 if (p->p_sysent->sv_mask)
1067 sa->code &= p->p_sysent->sv_mask;
1068 if (sa->code >= p->p_sysent->sv_size)
1069 sa->callp = &p->p_sysent->sv_table[0];
1071 sa->callp = &p->p_sysent->sv_table[sa->code];
1072 sa->narg = sa->callp->sy_narg;
1074 if (params != NULL && sa->narg != 0)
1075 error = copyin(params, (caddr_t)sa->args,
1076 (u_int)(sa->narg * sizeof(int)));
1081 td->td_retval[0] = 0;
1082 td->td_retval[1] = frame->tf_edx;
1088 #include "../../kern/subr_syscall.c"
1091 * syscall - system call request C handler. A system call is
1092 * essentially treated as a trap by reusing the frame layout.
1095 syscall(struct trapframe *frame)
1098 struct syscall_args sa;
1099 register_t orig_tf_eflags;
1104 if (!(TRAPF_USERMODE(frame) &&
1105 (curpcb->pcb_flags & PCB_VM86CALL) == 0)) {
1110 orig_tf_eflags = frame->tf_eflags;
1113 td->td_frame = frame;
1115 error = syscallenter(td, &sa);
1120 if ((orig_tf_eflags & PSL_T) && !(orig_tf_eflags & PSL_VM)) {
1121 frame->tf_eflags &= ~PSL_T;
1122 ksiginfo_init_trap(&ksi);
1123 ksi.ksi_signo = SIGTRAP;
1124 ksi.ksi_code = TRAP_TRACE;
1125 ksi.ksi_addr = (void *)frame->tf_eip;
1126 trapsignal(td, &ksi);
1129 KASSERT(PCB_USER_FPU(td->td_pcb),
1130 ("System call %s returning with kernel FPU ctx leaked",
1131 syscallname(td->td_proc, sa.code)));
1132 KASSERT(td->td_pcb->pcb_save == get_pcb_user_save_td(td),
1133 ("System call %s returning with mangled pcb_save",
1134 syscallname(td->td_proc, sa.code)));
1136 syscallret(td, error, &sa);