Exemplo n.º 1
0
void
trap(struct trapframe *frame)
{
#ifdef KDTRACE_HOOKS
	struct reg regs;
#endif
	struct thread *td = curthread;
	struct proc *p = td->td_proc;
	int i = 0, ucode = 0, code;
	u_int type;
	register_t addr = 0;
	ksiginfo_t ksi;

	PCPU_INC(cnt.v_trap);
	type = frame->tf_trapno;

#ifdef SMP
	/* Handler for NMI IPIs used for stopping CPUs. */
	if (type == T_NMI) {
	         if (ipi_nmi_handler() == 0)
	                   goto out;
	}
#endif /* SMP */

#ifdef KDB
	if (kdb_active) {
		kdb_reenter();
		goto out;
	}
#endif

	if (type == T_RESERVED) {
		trap_fatal(frame, 0);
		goto out;
	}

#ifdef	HWPMC_HOOKS
	/*
	 * CPU PMCs interrupt using an NMI.  If the PMC module is
	 * active, pass the 'rip' value to the PMC module's interrupt
	 * handler.  A return value of '1' from the handler means that
	 * the NMI was handled by it and we can return immediately.
	 */
	if (type == T_NMI && pmc_intr &&
	    (*pmc_intr)(PCPU_GET(cpuid), frame))
		goto out;
#endif

	if (type == T_MCHK) {
		mca_intr();
		goto out;
	}

#ifdef KDTRACE_HOOKS
	/*
	 * A trap can occur while DTrace executes a probe. Before
	 * executing the probe, DTrace blocks re-scheduling and sets
	 * a flag in its per-cpu flags to indicate that it doesn't
	 * want to fault. On returning from the probe, the no-fault
	 * flag is cleared and finally re-scheduling is enabled.
	 */
	if (dtrace_trap_func != NULL && (*dtrace_trap_func)(frame, type))
		goto out;
#endif

	if ((frame->tf_rflags & PSL_I) == 0) {
		/*
		 * Buggy application or kernel code has disabled
		 * interrupts and then trapped.  Enabling interrupts
		 * now is wrong, but it is better than running with
		 * interrupts disabled until they are accidentally
		 * enabled later.
		 */
		if (ISPL(frame->tf_cs) == SEL_UPL)
			uprintf(
			    "pid %ld (%s): trap %d with interrupts disabled\n",
			    (long)curproc->p_pid, curthread->td_name, type);
		else if (type != T_NMI && type != T_BPTFLT &&
		    type != T_TRCTRAP) {
			/*
			 * XXX not quite right, since this may be for a
			 * multiple fault in user mode.
			 */
			printf("kernel trap %d with interrupts disabled\n",
			    type);

			/*
			 * We shouldn't enable interrupts while holding a
			 * spin lock.
			 */
			if (td->td_md.md_spinlock_count == 0)
				enable_intr();
		}
	}

	code = frame->tf_err;

        if (ISPL(frame->tf_cs) == SEL_UPL) {
		/* user trap */

		td->td_pticks = 0;
		td->td_frame = frame;
		addr = frame->tf_rip;
		if (td->td_ucred != p->p_ucred) 
			cred_update_thread(td);

		switch (type) {
		case T_PRIVINFLT:	/* privileged instruction fault */
			i = SIGILL;
			ucode = ILL_PRVOPC;
			break;

		case T_BPTFLT:		/* bpt instruction fault */
		case T_TRCTRAP:		/* trace trap */
			enable_intr();
#ifdef KDTRACE_HOOKS
			if (type == T_BPTFLT) {
				fill_frame_regs(frame, &regs);
				if (dtrace_pid_probe_ptr != NULL &&
				    dtrace_pid_probe_ptr(&regs) == 0)
					goto out;
			}
#endif
			frame->tf_rflags &= ~PSL_T;
			i = SIGTRAP;
			ucode = (type == T_TRCTRAP ? TRAP_TRACE : TRAP_BRKPT);
			break;

		case T_ARITHTRAP:	/* arithmetic trap */
			ucode = fputrap_x87();
			if (ucode == -1)
				goto userout;
			i = SIGFPE;
			break;

		case T_PROTFLT:		/* general protection fault */
			i = SIGBUS;
			ucode = BUS_OBJERR;
			break;
		case T_STKFLT:		/* stack fault */
		case T_SEGNPFLT:	/* segment not present fault */
			i = SIGBUS;
			ucode = BUS_ADRERR;
			break;
		case T_TSSFLT:		/* invalid TSS fault */
			i = SIGBUS;
			ucode = BUS_OBJERR;
			break;
		case T_DOUBLEFLT:	/* double fault */
		default:
			i = SIGBUS;
			ucode = BUS_OBJERR;
			break;

		case T_PAGEFLT:		/* page fault */
			addr = frame->tf_addr;
			i = trap_pfault(frame, TRUE);
			if (i == -1)
				goto userout;
			if (i == 0)
				goto user;

			if (i == SIGSEGV)
				ucode = SEGV_MAPERR;
			else {
				if (prot_fault_translation == 0) {
					/*
					 * Autodetect.
					 * This check also covers the images
					 * without the ABI-tag ELF note.
					 */
					if (SV_CURPROC_ABI() == SV_ABI_FREEBSD
					    && p->p_osrel >= P_OSREL_SIGSEGV) {
						i = SIGSEGV;
						ucode = SEGV_ACCERR;
					} else {
						i = SIGBUS;
						ucode = BUS_PAGE_FAULT;
					}
				} else if (prot_fault_translation == 1) {
					/*
					 * Always compat mode.
					 */
					i = SIGBUS;
					ucode = BUS_PAGE_FAULT;
				} else {
					/*
					 * Always SIGSEGV mode.
					 */
					i = SIGSEGV;
					ucode = SEGV_ACCERR;
				}
			}
			break;

		case T_DIVIDE:		/* integer divide fault */
			ucode = FPE_INTDIV;
			i = SIGFPE;
			break;

#ifdef DEV_ISA
		case T_NMI:
			/* machine/parity/power fail/"kitchen sink" faults */
			if (isa_nmi(code) == 0) {
#ifdef KDB
				/*
				 * NMI can be hooked up to a pushbutton
				 * for debugging.
				 */
				if (kdb_on_nmi) {
					printf ("NMI ... going to debugger\n");
					kdb_trap(type, 0, frame);
				}
#endif /* KDB */
				goto userout;
			} else if (panic_on_nmi)
				panic("NMI indicates hardware failure");
			break;
#endif /* DEV_ISA */

		case T_OFLOW:		/* integer overflow fault */
			ucode = FPE_INTOVF;
			i = SIGFPE;
			break;

		case T_BOUND:		/* bounds check fault */
			ucode = FPE_FLTSUB;
			i = SIGFPE;
			break;

		case T_DNA:
			/* transparent fault (due to context switch "late") */
			KASSERT(PCB_USER_FPU(td->td_pcb),
			    ("kernel FPU ctx has leaked"));
			fpudna();
			goto userout;

		case T_FPOPFLT:		/* FPU operand fetch fault */
			ucode = ILL_COPROC;
			i = SIGILL;
			break;

		case T_XMMFLT:		/* SIMD floating-point exception */
			ucode = fputrap_sse();
			if (ucode == -1)
				goto userout;
			i = SIGFPE;
			break;
#ifdef KDTRACE_HOOKS
		case T_DTRACE_RET:
			enable_intr();
			fill_frame_regs(frame, &regs);
			if (dtrace_return_probe_ptr != NULL &&
			    dtrace_return_probe_ptr(&regs) == 0)
				goto out;
			break;
#endif
		}
	} else {
		/* kernel trap */

		KASSERT(cold || td->td_ucred != NULL,
		    ("kernel trap doesn't have ucred"));
		switch (type) {
		case T_PAGEFLT:			/* page fault */
			(void) trap_pfault(frame, FALSE);
			goto out;

		case T_DNA:
			KASSERT(!PCB_USER_FPU(td->td_pcb),
			    ("Unregistered use of FPU in kernel"));
			fpudna();
			goto out;

		case T_ARITHTRAP:	/* arithmetic trap */
		case T_XMMFLT:		/* SIMD floating-point exception */
		case T_FPOPFLT:		/* FPU operand fetch fault */
			/*
			 * XXXKIB for now disable any FPU traps in kernel
			 * handler registration seems to be overkill
			 */
			trap_fatal(frame, 0);
			goto out;

		case T_STKFLT:		/* stack fault */
			break;

		case T_PROTFLT:		/* general protection fault */
		case T_SEGNPFLT:	/* segment not present fault */
			if (td->td_intr_nesting_level != 0)
				break;

			/*
			 * Invalid segment selectors and out of bounds
			 * %rip's and %rsp's can be set up in user mode.
			 * This causes a fault in kernel mode when the
			 * kernel tries to return to user mode.  We want
			 * to get this fault so that we can fix the
			 * problem here and not have to check all the
			 * selectors and pointers when the user changes
			 * them.
			 */
			if (frame->tf_rip == (long)doreti_iret) {
				frame->tf_rip = (long)doreti_iret_fault;
				goto out;
			}
			if (frame->tf_rip == (long)ld_ds) {
				frame->tf_rip = (long)ds_load_fault;
				goto out;
			}
			if (frame->tf_rip == (long)ld_es) {
				frame->tf_rip = (long)es_load_fault;
				goto out;
			}
			if (frame->tf_rip == (long)ld_fs) {
				frame->tf_rip = (long)fs_load_fault;
				goto out;
			}
			if (frame->tf_rip == (long)ld_gs) {
				frame->tf_rip = (long)gs_load_fault;
				goto out;
			}
			if (frame->tf_rip == (long)ld_gsbase) {
				frame->tf_rip = (long)gsbase_load_fault;
				goto out;
			}
			if (frame->tf_rip == (long)ld_fsbase) {
				frame->tf_rip = (long)fsbase_load_fault;
				goto out;
			}
			if (curpcb->pcb_onfault != NULL) {
				frame->tf_rip = (long)curpcb->pcb_onfault;
				goto out;
			}
			break;

		case T_TSSFLT:
			/*
			 * PSL_NT can be set in user mode and isn't cleared
			 * automatically when the kernel is entered.  This
			 * causes a TSS fault when the kernel attempts to
			 * `iret' because the TSS link is uninitialized.  We
			 * want to get this fault so that we can fix the
			 * problem here and not every time the kernel is
			 * entered.
			 */
			if (frame->tf_rflags & PSL_NT) {
				frame->tf_rflags &= ~PSL_NT;
				goto out;
			}
			break;

		case T_TRCTRAP:	 /* trace trap */
			/*
			 * Ignore debug register trace traps due to
			 * accesses in the user's address space, which
			 * can happen under several conditions such as
			 * if a user sets a watchpoint on a buffer and
			 * then passes that buffer to a system call.
			 * We still want to get TRCTRAPS for addresses
			 * in kernel space because that is useful when
			 * debugging the kernel.
			 */
			if (user_dbreg_trap()) {
				/*
				 * Reset breakpoint bits because the
				 * processor doesn't
				 */
				/* XXX check upper bits here */
				load_dr6(rdr6() & 0xfffffff0);
				goto out;
			}
			/*
			 * FALLTHROUGH (TRCTRAP kernel mode, kernel address)
			 */
		case T_BPTFLT:
			/*
			 * If KDB is enabled, let it handle the debugger trap.
			 * Otherwise, debugger traps "can't happen".
			 */
#ifdef KDB
			if (kdb_trap(type, 0, frame))
				goto out;
#endif
			break;

#ifdef DEV_ISA
		case T_NMI:
			/* machine/parity/power fail/"kitchen sink" faults */
			if (isa_nmi(code) == 0) {
#ifdef KDB
				/*
				 * NMI can be hooked up to a pushbutton
				 * for debugging.
				 */
				if (kdb_on_nmi) {
					printf ("NMI ... going to debugger\n");
					kdb_trap(type, 0, frame);
				}
#endif /* KDB */
				goto out;
			} else if (panic_on_nmi == 0)
				goto out;
			/* FALLTHROUGH */
#endif /* DEV_ISA */
		}

		trap_fatal(frame, 0);
		goto out;
	}

	/* Translate fault for emulators (e.g. Linux) */
	if (*p->p_sysent->sv_transtrap)
		i = (*p->p_sysent->sv_transtrap)(i, type);

	ksiginfo_init_trap(&ksi);
	ksi.ksi_signo = i;
	ksi.ksi_code = ucode;
	ksi.ksi_trapno = type;
	ksi.ksi_addr = (void *)addr;
	if (uprintf_signal) {
		uprintf("pid %d comm %s: signal %d err %lx code %d type %d "
		    "addr 0x%lx rsp 0x%lx rip 0x%lx "
		    "<%02x %02x %02x %02x %02x %02x %02x %02x>\n",
		    p->p_pid, p->p_comm, i, frame->tf_err, ucode, type, addr,
		    frame->tf_rsp, frame->tf_rip,
		    fubyte((void *)(frame->tf_rip + 0)),
		    fubyte((void *)(frame->tf_rip + 1)),
		    fubyte((void *)(frame->tf_rip + 2)),
		    fubyte((void *)(frame->tf_rip + 3)),
		    fubyte((void *)(frame->tf_rip + 4)),
		    fubyte((void *)(frame->tf_rip + 5)),
		    fubyte((void *)(frame->tf_rip + 6)),
		    fubyte((void *)(frame->tf_rip + 7)));
	}
	KASSERT((read_rflags() & PSL_I) != 0, ("interrupts disabled"));
	trapsignal(td, &ksi);

user:
	userret(td, frame);
	KASSERT(PCB_USER_FPU(td->td_pcb),
	    ("Return from trap with kernel FPU ctx leaked"));
userout:
out:
	return;
}
Exemplo n.º 2
0
void
trap(struct trapframe *frame)
{
	struct thread *td = curthread;
	struct proc *p = td->td_proc;
	int i = 0, ucode = 0, code;
	u_int type;
	register_t addr = 0;
	vm_offset_t eva;
	ksiginfo_t ksi;
#ifdef POWERFAIL_NMI
	static int lastalert = 0;
#endif

	PCPU_INC(cnt.v_trap);
	type = frame->tf_trapno;

#ifdef SMP
	/* Handler for NMI IPIs used for stopping CPUs. */
	if (type == T_NMI) {
	         if (ipi_nmi_handler() == 0)
	                   goto out;
	}
#endif /* SMP */

#ifdef KDB
	if (kdb_active) {
		kdb_reenter();
		goto out;
	}
#endif

	if (type == T_RESERVED) {
		trap_fatal(frame, 0);
		goto out;
	}

#ifdef	HWPMC_HOOKS
	/*
	 * CPU PMCs interrupt using an NMI so we check for that first.
	 * If the HWPMC module is active, 'pmc_hook' will point to
	 * the function to be called.  A return value of '1' from the
	 * hook means that the NMI was handled by it and that we can
	 * return immediately.
	 */
	if (type == T_NMI && pmc_intr &&
	    (*pmc_intr)(PCPU_GET(cpuid), frame))
	    goto out;
#endif

	if (type == T_MCHK) {
		if (!mca_intr())
			trap_fatal(frame, 0);
		goto out;
	}

#ifdef KDTRACE_HOOKS
	/*
	 * A trap can occur while DTrace executes a probe. Before
	 * executing the probe, DTrace blocks re-scheduling and sets
	 * a flag in it's per-cpu flags to indicate that it doesn't
	 * want to fault. On returning from the probe, the no-fault
	 * flag is cleared and finally re-scheduling is enabled.
	 *
	 * If the DTrace kernel module has registered a trap handler,
	 * call it and if it returns non-zero, assume that it has
	 * handled the trap and modified the trap frame so that this
	 * function can return normally.
	 */
	if ((type == T_PROTFLT || type == T_PAGEFLT) &&
	    dtrace_trap_func != NULL)
		if ((*dtrace_trap_func)(frame, type))
			goto out;
	if (type == T_DTRACE_PROBE || type == T_DTRACE_RET ||
	    type == T_BPTFLT) {
		struct reg regs;

		fill_frame_regs(frame, &regs);
		if (type == T_DTRACE_PROBE &&
		    dtrace_fasttrap_probe_ptr != NULL &&
		    dtrace_fasttrap_probe_ptr(&regs) == 0)
			goto out;
		if (type == T_BPTFLT &&
		    dtrace_pid_probe_ptr != NULL &&
		    dtrace_pid_probe_ptr(&regs) == 0)
			goto out;
		if (type == T_DTRACE_RET &&
		    dtrace_return_probe_ptr != NULL &&
		    dtrace_return_probe_ptr(&regs) == 0)
			goto out;
	}
#endif

	if ((frame->tf_eflags & PSL_I) == 0) {
		/*
		 * Buggy application or kernel code has disabled
		 * interrupts and then trapped.  Enabling interrupts
		 * now is wrong, but it is better than running with
		 * interrupts disabled until they are accidentally
		 * enabled later.
		 */
		if (ISPL(frame->tf_cs) == SEL_UPL || (frame->tf_eflags & PSL_VM))
			uprintf(
			    "pid %ld (%s): trap %d with interrupts disabled\n",
			    (long)curproc->p_pid, curthread->td_name, type);
		else if (type != T_BPTFLT && type != T_TRCTRAP &&
			 frame->tf_eip != (int)cpu_switch_load_gs) {
			/*
			 * XXX not quite right, since this may be for a
			 * multiple fault in user mode.
			 */
			printf("kernel trap %d with interrupts disabled\n",
			    type);
			/*
			 * Page faults need interrupts disabled until later,
			 * and we shouldn't enable interrupts while holding
			 * a spin lock or if servicing an NMI.
			 */
			if (type != T_NMI && type != T_PAGEFLT &&
			    td->td_md.md_spinlock_count == 0)
				enable_intr();
		}
	}
	eva = 0;
	code = frame->tf_err;
	if (type == T_PAGEFLT) {
		/*
		 * For some Cyrix CPUs, %cr2 is clobbered by
		 * interrupts.  This problem is worked around by using
		 * an interrupt gate for the pagefault handler.  We
		 * are finally ready to read %cr2 and then must
		 * reenable interrupts.
		 *
		 * If we get a page fault while in a critical section, then
		 * it is most likely a fatal kernel page fault.  The kernel
		 * is already going to panic trying to get a sleep lock to
		 * do the VM lookup, so just consider it a fatal trap so the
		 * kernel can print out a useful trap message and even get
		 * to the debugger.
		 *
		 * If we get a page fault while holding a non-sleepable
		 * lock, then it is most likely a fatal kernel page fault.
		 * If WITNESS is enabled, then it's going to whine about
		 * bogus LORs with various VM locks, so just skip to the
		 * fatal trap handling directly.
		 */
		eva = rcr2();
		if (td->td_critnest != 0 ||
		    WITNESS_CHECK(WARN_SLEEPOK | WARN_GIANTOK, NULL,
		    "Kernel page fault") != 0)
			trap_fatal(frame, eva);
		else
			enable_intr();
	}

        if ((ISPL(frame->tf_cs) == SEL_UPL) ||
	    ((frame->tf_eflags & PSL_VM) && 
		!(PCPU_GET(curpcb)->pcb_flags & PCB_VM86CALL))) {
		/* user trap */

		td->td_pticks = 0;
		td->td_frame = frame;
		addr = frame->tf_eip;
		if (td->td_ucred != p->p_ucred) 
			cred_update_thread(td);

		switch (type) {
		case T_PRIVINFLT:	/* privileged instruction fault */
			i = SIGILL;
			ucode = ILL_PRVOPC;
			break;

		case T_BPTFLT:		/* bpt instruction fault */
		case T_TRCTRAP:		/* trace trap */
			enable_intr();
			frame->tf_eflags &= ~PSL_T;
			i = SIGTRAP;
			ucode = (type == T_TRCTRAP ? TRAP_TRACE : TRAP_BRKPT);
			break;

		case T_ARITHTRAP:	/* arithmetic trap */
#ifdef DEV_NPX
			ucode = npxtrap();
			if (ucode == -1)
				goto userout;
#else
			ucode = 0;
#endif
			i = SIGFPE;
			break;

			/*
			 * The following two traps can happen in
			 * vm86 mode, and, if so, we want to handle
			 * them specially.
			 */
		case T_PROTFLT:		/* general protection fault */
		case T_STKFLT:		/* stack fault */
			if (frame->tf_eflags & PSL_VM) {
				i = vm86_emulate((struct vm86frame *)frame);
				if (i == 0)
					goto user;
				break;
			}
			i = SIGBUS;
			ucode = (type == T_PROTFLT) ? BUS_OBJERR : BUS_ADRERR;
			break;
		case T_SEGNPFLT:	/* segment not present fault */
			i = SIGBUS;
			ucode = BUS_ADRERR;
			break;
		case T_TSSFLT:		/* invalid TSS fault */
			i = SIGBUS;
			ucode = BUS_OBJERR;
			break;
		case T_DOUBLEFLT:	/* double fault */
		default:
			i = SIGBUS;
			ucode = BUS_OBJERR;
			break;

		case T_PAGEFLT:		/* page fault */

			i = trap_pfault(frame, TRUE, eva);
#if defined(I586_CPU) && !defined(NO_F00F_HACK)
			if (i == -2) {
				/*
				 * The f00f hack workaround has triggered, so
				 * treat the fault as an illegal instruction 
				 * (T_PRIVINFLT) instead of a page fault.
				 */
				type = frame->tf_trapno = T_PRIVINFLT;

				/* Proceed as in that case. */
				ucode = ILL_PRVOPC;
				i = SIGILL;
				break;
			}
#endif
			if (i == -1)
				goto userout;
			if (i == 0)
				goto user;

			if (i == SIGSEGV)
				ucode = SEGV_MAPERR;
			else {
				if (prot_fault_translation == 0) {
					/*
					 * Autodetect.
					 * This check also covers the images
					 * without the ABI-tag ELF note.
					 */
					if (SV_CURPROC_ABI() == SV_ABI_FREEBSD
					    && p->p_osrel >= P_OSREL_SIGSEGV) {
						i = SIGSEGV;
						ucode = SEGV_ACCERR;
					} else {
						i = SIGBUS;
						ucode = BUS_PAGE_FAULT;
					}
				} else if (prot_fault_translation == 1) {
					/*
					 * Always compat mode.
					 */
					i = SIGBUS;
					ucode = BUS_PAGE_FAULT;
				} else {
					/*
					 * Always SIGSEGV mode.
					 */
					i = SIGSEGV;
					ucode = SEGV_ACCERR;
				}
			}
			addr = eva;
			break;

		case T_DIVIDE:		/* integer divide fault */
			ucode = FPE_INTDIV;
			i = SIGFPE;
			break;

#ifdef DEV_ISA
		case T_NMI:
#ifdef POWERFAIL_NMI
#ifndef TIMER_FREQ
#  define TIMER_FREQ 1193182
#endif
			if (time_second - lastalert > 10) {
				log(LOG_WARNING, "NMI: power fail\n");
				sysbeep(880, hz);
				lastalert = time_second;
			}
			goto userout;
#else /* !POWERFAIL_NMI */
			/* machine/parity/power fail/"kitchen sink" faults */
			if (isa_nmi(code) == 0) {
#ifdef KDB
				/*
				 * NMI can be hooked up to a pushbutton
				 * for debugging.
				 */
				if (kdb_on_nmi) {
					printf ("NMI ... going to debugger\n");
					kdb_trap(type, 0, frame);
				}
#endif /* KDB */
				goto userout;
			} else if (panic_on_nmi)
				panic("NMI indicates hardware failure");
			break;
#endif /* POWERFAIL_NMI */
#endif /* DEV_ISA */

		case T_OFLOW:		/* integer overflow fault */
			ucode = FPE_INTOVF;
			i = SIGFPE;
			break;

		case T_BOUND:		/* bounds check fault */
			ucode = FPE_FLTSUB;
			i = SIGFPE;
			break;

		case T_DNA:
#ifdef DEV_NPX
			KASSERT(PCB_USER_FPU(td->td_pcb),
			    ("kernel FPU ctx has leaked"));
			/* transparent fault (due to context switch "late") */
			if (npxdna())
				goto userout;
#endif
			uprintf("pid %d killed due to lack of floating point\n",
				p->p_pid);
			i = SIGKILL;
			ucode = 0;
			break;

		case T_FPOPFLT:		/* FPU operand fetch fault */
			ucode = ILL_COPROC;
			i = SIGILL;
			break;

		case T_XMMFLT:		/* SIMD floating-point exception */
			ucode = 0; /* XXX */
			i = SIGFPE;
			break;
		}
	} else {
		/* kernel trap */

		KASSERT(cold || td->td_ucred != NULL,
		    ("kernel trap doesn't have ucred"));
		switch (type) {
		case T_PAGEFLT:			/* page fault */
			(void) trap_pfault(frame, FALSE, eva);
			goto out;

		case T_DNA:
#ifdef DEV_NPX
			KASSERT(!PCB_USER_FPU(td->td_pcb),
			    ("Unregistered use of FPU in kernel"));
			if (npxdna())
				goto out;
#endif
			break;

		case T_ARITHTRAP:	/* arithmetic trap */
		case T_XMMFLT:		/* SIMD floating-point exception */
		case T_FPOPFLT:		/* FPU operand fetch fault */
			/*
			 * XXXKIB for now disable any FPU traps in kernel
			 * handler registration seems to be overkill
			 */
			trap_fatal(frame, 0);
			goto out;

			/*
			 * The following two traps can happen in
			 * vm86 mode, and, if so, we want to handle
			 * them specially.
			 */
		case T_PROTFLT:		/* general protection fault */
		case T_STKFLT:		/* stack fault */
			if (frame->tf_eflags & PSL_VM) {
				i = vm86_emulate((struct vm86frame *)frame);
				if (i != 0)
					/*
					 * returns to original process
					 */
					vm86_trap((struct vm86frame *)frame);
				goto out;
			}
			if (type == T_STKFLT)
				break;

			/* FALL THROUGH */

		case T_SEGNPFLT:	/* segment not present fault */
			if (PCPU_GET(curpcb)->pcb_flags & PCB_VM86CALL)
				break;

			/*
			 * Invalid %fs's and %gs's can be created using
			 * procfs or PT_SETREGS or by invalidating the
			 * underlying LDT entry.  This causes a fault
			 * in kernel mode when the kernel attempts to
			 * switch contexts.  Lose the bad context
			 * (XXX) so that we can continue, and generate
			 * a signal.
			 */
			if (frame->tf_eip == (int)cpu_switch_load_gs) {
				PCPU_GET(curpcb)->pcb_gs = 0;
#if 0				
				PROC_LOCK(p);
				kern_psignal(p, SIGBUS);
				PROC_UNLOCK(p);
#endif				
				goto out;
			}

			if (td->td_intr_nesting_level != 0)
				break;

			/*
			 * Invalid segment selectors and out of bounds
			 * %eip's and %esp's can be set up in user mode.
			 * This causes a fault in kernel mode when the
			 * kernel tries to return to user mode.  We want
			 * to get this fault so that we can fix the
			 * problem here and not have to check all the
			 * selectors and pointers when the user changes
			 * them.
			 */
			if (frame->tf_eip == (int)doreti_iret) {
				frame->tf_eip = (int)doreti_iret_fault;
				goto out;
			}
			if (frame->tf_eip == (int)doreti_popl_ds) {
				frame->tf_eip = (int)doreti_popl_ds_fault;
				goto out;
			}
			if (frame->tf_eip == (int)doreti_popl_es) {
				frame->tf_eip = (int)doreti_popl_es_fault;
				goto out;
			}
			if (frame->tf_eip == (int)doreti_popl_fs) {
				frame->tf_eip = (int)doreti_popl_fs_fault;
				goto out;
			}
			if (PCPU_GET(curpcb)->pcb_onfault != NULL) {
				frame->tf_eip =
				    (int)PCPU_GET(curpcb)->pcb_onfault;
				goto out;
			}
			break;

		case T_TSSFLT:
			/*
			 * PSL_NT can be set in user mode and isn't cleared
			 * automatically when the kernel is entered.  This
			 * causes a TSS fault when the kernel attempts to
			 * `iret' because the TSS link is uninitialized.  We
			 * want to get this fault so that we can fix the
			 * problem here and not every time the kernel is
			 * entered.
			 */
			if (frame->tf_eflags & PSL_NT) {
				frame->tf_eflags &= ~PSL_NT;
				goto out;
			}
			break;

		case T_TRCTRAP:	 /* trace trap */
			if (frame->tf_eip == (int)IDTVEC(lcall_syscall)) {
				/*
				 * We've just entered system mode via the
				 * syscall lcall.  Continue single stepping
				 * silently until the syscall handler has
				 * saved the flags.
				 */
				goto out;
			}
			if (frame->tf_eip == (int)IDTVEC(lcall_syscall) + 1) {
				/*
				 * The syscall handler has now saved the
				 * flags.  Stop single stepping it.
				 */
				frame->tf_eflags &= ~PSL_T;
				goto out;
			}
			/*
			 * Ignore debug register trace traps due to
			 * accesses in the user's address space, which
			 * can happen under several conditions such as
			 * if a user sets a watchpoint on a buffer and
			 * then passes that buffer to a system call.
			 * We still want to get TRCTRAPS for addresses
			 * in kernel space because that is useful when
			 * debugging the kernel.
			 */
			if (user_dbreg_trap() && 
			   !(PCPU_GET(curpcb)->pcb_flags & PCB_VM86CALL)) {
				/*
				 * Reset breakpoint bits because the
				 * processor doesn't
				 */
				load_dr6(rdr6() & 0xfffffff0);
				goto out;
			}
			/*
			 * FALLTHROUGH (TRCTRAP kernel mode, kernel address)
			 */
		case T_BPTFLT:
			/*
			 * If KDB is enabled, let it handle the debugger trap.
			 * Otherwise, debugger traps "can't happen".
			 */
#ifdef KDB
			if (kdb_trap(type, 0, frame))
				goto out;
#endif
			break;

#ifdef DEV_ISA
		case T_NMI:
#ifdef POWERFAIL_NMI
			if (time_second - lastalert > 10) {
				log(LOG_WARNING, "NMI: power fail\n");
				sysbeep(880, hz);
				lastalert = time_second;
			}
			goto out;
#else /* !POWERFAIL_NMI */
			/* machine/parity/power fail/"kitchen sink" faults */
			if (isa_nmi(code) == 0) {
#ifdef KDB
				/*
				 * NMI can be hooked up to a pushbutton
				 * for debugging.
				 */
				if (kdb_on_nmi) {
					printf ("NMI ... going to debugger\n");
					kdb_trap(type, 0, frame);
				}
#endif /* KDB */
				goto out;
			} else if (panic_on_nmi == 0)
				goto out;
			/* FALLTHROUGH */
#endif /* POWERFAIL_NMI */
#endif /* DEV_ISA */
		}

		trap_fatal(frame, eva);
		goto out;
	}

	/* Translate fault for emulators (e.g. Linux) */
	if (*p->p_sysent->sv_transtrap)
		i = (*p->p_sysent->sv_transtrap)(i, type);

	ksiginfo_init_trap(&ksi);
	ksi.ksi_signo = i;
	ksi.ksi_code = ucode;
	ksi.ksi_addr = (void *)addr;
	ksi.ksi_trapno = type;
	trapsignal(td, &ksi);

#ifdef DEBUG
	if (type <= MAX_TRAP_MSG) {
		uprintf("fatal process exception: %s",
			trap_msg[type]);
		if ((type == T_PAGEFLT) || (type == T_PROTFLT))
			uprintf(", fault VA = 0x%lx", (u_long)eva);
		uprintf("\n");
	}
#endif

user:
	userret(td, frame);
	mtx_assert(&Giant, MA_NOTOWNED);
	KASSERT(PCB_USER_FPU(td->td_pcb),
	    ("Return from trap with kernel FPU ctx leaked"));
userout:
out:
	return;
}
Exemplo n.º 3
0
/*
 * Exception, fault, and trap interface to the kernel.
 * This common code is called from assembly language IDT gate entry
 * routines that prepare a suitable stack frame, and restore this
 * frame after the exception has been processed.
 *
 * This function is also called from doreti in an interlock to handle ASTs.
 * For example:  hardwareint->INTROUTINE->(set ast)->doreti->trap
 *
 * NOTE!  We have to retrieve the fault address prior to potentially
 *	  blocking, including blocking on any token.
 *
 * NOTE!  NMI and kernel DBG traps remain on their respective pcpu IST
 *	  stacks if taken from a kernel RPL. trap() cannot block in this
 *	  situation.  DDB entry or a direct report-and-return is ok.
 *
 * XXX gd_trap_nesting_level currently prevents lwkt_switch() from panicing
 * if an attempt is made to switch from a fast interrupt or IPI.
 */
void
trap(struct trapframe *frame)
{
	static struct krate sscpubugrate = { 1 };
	struct globaldata *gd = mycpu;
	struct thread *td = gd->gd_curthread;
	struct lwp *lp = td->td_lwp;
	struct proc *p;
	int sticks = 0;
	int i = 0, ucode = 0, type, code;
#ifdef INVARIANTS
	int crit_count = td->td_critcount;
	lwkt_tokref_t curstop = td->td_toks_stop;
#endif
	vm_offset_t eva;

	p = td->td_proc;
	clear_quickret();

#ifdef DDB
        /*
	 * We need to allow T_DNA faults when the debugger is active since
	 * some dumping paths do large bcopy() which use the floating
	 * point registers for faster copying.
	 */
	if (db_active && frame->tf_trapno != T_DNA) {
		eva = (frame->tf_trapno == T_PAGEFLT ? frame->tf_addr : 0);
		++gd->gd_trap_nesting_level;
		trap_fatal(frame, eva);
		--gd->gd_trap_nesting_level;
		goto out2;
	}
#endif

	eva = 0;

	if ((frame->tf_rflags & PSL_I) == 0) {
		/*
		 * Buggy application or kernel code has disabled interrupts
		 * and then trapped.  Enabling interrupts now is wrong, but
		 * it is better than running with interrupts disabled until
		 * they are accidentally enabled later.
		 */

		type = frame->tf_trapno;
		if (ISPL(frame->tf_cs) == SEL_UPL) {
			/* JG curproc can be NULL */
			kprintf(
			    "pid %ld (%s): trap %d with interrupts disabled\n",
			    (long)curproc->p_pid, curproc->p_comm, type);
		} else if ((type == T_STKFLT || type == T_PROTFLT ||
			    type == T_SEGNPFLT) &&
			   frame->tf_rip == (long)doreti_iret) {
			/*
			 * iretq fault from kernel mode during return to
			 * userland.
			 *
			 * This situation is expected, don't complain.
			 */
		} else if (type != T_NMI && type != T_BPTFLT &&
			   type != T_TRCTRAP) {
			/*
			 * XXX not quite right, since this may be for a
			 * multiple fault in user mode.
			 */
			kprintf("kernel trap %d (%s @ 0x%016jx) with "
				"interrupts disabled\n",
				type,
				td->td_comm,
				frame->tf_rip);
		}
		cpu_enable_intr();
	}

	type = frame->tf_trapno;
	code = frame->tf_err;

	if (ISPL(frame->tf_cs) == SEL_UPL) {
		/* user trap */

		KTR_LOG(kernentry_trap, p->p_pid, lp->lwp_tid,
			frame->tf_trapno, eva);

		userenter(td, p);

		sticks = (int)td->td_sticks;
		KASSERT(lp->lwp_md.md_regs == frame,
			("Frame mismatch %p %p", lp->lwp_md.md_regs, frame));

		switch (type) {
		case T_PRIVINFLT:	/* privileged instruction fault */
			i = SIGILL;
			ucode = ILL_PRVOPC;
			break;

		case T_BPTFLT:		/* bpt instruction fault */
		case T_TRCTRAP:		/* trace trap */
			frame->tf_rflags &= ~PSL_T;
			i = SIGTRAP;
			ucode = (type == T_TRCTRAP ? TRAP_TRACE : TRAP_BRKPT);
			break;

		case T_ARITHTRAP:	/* arithmetic trap */
			ucode = code;
			i = SIGFPE;
			break;

		case T_ASTFLT:		/* Allow process switch */
			mycpu->gd_cnt.v_soft++;
			if (mycpu->gd_reqflags & RQF_AST_OWEUPC) {
				atomic_clear_int(&mycpu->gd_reqflags,
						 RQF_AST_OWEUPC);
				addupc_task(p, p->p_prof.pr_addr,
					    p->p_prof.pr_ticks);
			}
			goto out;

		case T_PROTFLT:		/* general protection fault */
			i = SIGBUS;
			ucode = BUS_OBJERR;
			break;
		case T_STKFLT:		/* stack fault */
		case T_SEGNPFLT:	/* segment not present fault */
			i = SIGBUS;
			ucode = BUS_ADRERR;
			break;
		case T_TSSFLT:		/* invalid TSS fault */
		case T_DOUBLEFLT:	/* double fault */
		default:
			i = SIGBUS;
			ucode = BUS_OBJERR;
			break;

		case T_PAGEFLT:		/* page fault */
			i = trap_pfault(frame, TRUE);
#ifdef DDB
			if (frame->tf_rip == 0) {
				/* used for kernel debugging only */
				while (freeze_on_seg_fault)
					tsleep(p, 0, "freeze", hz * 20);
			}
#endif
			if (i == -1 || i == 0)
				goto out;
			if (i == SIGSEGV) {
				ucode = SEGV_MAPERR;
			} else {
				i = SIGSEGV;
				ucode = SEGV_ACCERR;
			}
			break;

		case T_DIVIDE:		/* integer divide fault */
			ucode = FPE_INTDIV;
			i = SIGFPE;
			break;

#if NISA > 0
		case T_NMI:
			/* machine/parity/power fail/"kitchen sink" faults */
			if (isa_nmi(code) == 0) {
#ifdef DDB
				/*
				 * NMI can be hooked up to a pushbutton
				 * for debugging.
				 */
				if (ddb_on_nmi) {
					kprintf ("NMI ... going to debugger\n");
					kdb_trap(type, 0, frame);
				}
#endif /* DDB */
				goto out2;
			} else if (panic_on_nmi)
				panic("NMI indicates hardware failure");
			break;
#endif /* NISA > 0 */

		case T_OFLOW:		/* integer overflow fault */
			ucode = FPE_INTOVF;
			i = SIGFPE;
			break;

		case T_BOUND:		/* bounds check fault */
			ucode = FPE_FLTSUB;
			i = SIGFPE;
			break;

		case T_DNA:
			/*
			 * Virtual kernel intercept - pass the DNA exception
			 * to the virtual kernel if it asked to handle it.
			 * This occurs when the virtual kernel is holding
			 * onto the FP context for a different emulated
			 * process then the one currently running.
			 *
			 * We must still call npxdna() since we may have
			 * saved FP state that the virtual kernel needs
			 * to hand over to a different emulated process.
			 */
			if (lp->lwp_vkernel && lp->lwp_vkernel->ve &&
			    (td->td_pcb->pcb_flags & FP_VIRTFP)
			) {
				npxdna();
				break;
			}

			/*
			 * The kernel may have switched out the FP unit's
			 * state, causing the user process to take a fault
			 * when it tries to use the FP unit.  Restore the
			 * state here
			 */
			if (npxdna()) {
				gd->gd_cnt.v_trap++;
				goto out;
			}
			i = SIGFPE;
			ucode = FPE_FPU_NP_TRAP;
			break;

		case T_FPOPFLT:		/* FPU operand fetch fault */
			ucode = ILL_COPROC;
			i = SIGILL;
			break;

		case T_XMMFLT:		/* SIMD floating-point exception */
			ucode = 0; /* XXX */
			i = SIGFPE;
			break;
		}
	} else {
		/* kernel trap */

		switch (type) {
		case T_PAGEFLT:			/* page fault */
			trap_pfault(frame, FALSE);
			goto out2;

		case T_DNA:
			/*
			 * The kernel is apparently using fpu for copying.
			 * XXX this should be fatal unless the kernel has
			 * registered such use.
			 */
			if (npxdna()) {
				gd->gd_cnt.v_trap++;
				goto out2;
			}
			break;

		case T_STKFLT:		/* stack fault */
		case T_PROTFLT:		/* general protection fault */
		case T_SEGNPFLT:	/* segment not present fault */
			/*
			 * Invalid segment selectors and out of bounds
			 * %rip's and %rsp's can be set up in user mode.
			 * This causes a fault in kernel mode when the
			 * kernel tries to return to user mode.  We want
			 * to get this fault so that we can fix the
			 * problem here and not have to check all the
			 * selectors and pointers when the user changes
			 * them.
			 */
			if (mycpu->gd_intr_nesting_level == 0) {
				/*
				 * NOTE: in 64-bit mode traps push rsp/ss
				 *	 even if no ring change occurs.
				 */
				if (td->td_pcb->pcb_onfault &&
				    td->td_pcb->pcb_onfault_sp ==
				    frame->tf_rsp) {
					frame->tf_rip = (register_t)
						td->td_pcb->pcb_onfault;
					goto out2;
				}

				/*
				 * If the iretq in doreti faults during
				 * return to user, it will be special-cased
				 * in IDTVEC(prot) to get here.  We want
				 * to 'return' to doreti_iret_fault in
				 * ipl.s in approximately the same state we
				 * were in at the iretq.
				 */
				if (frame->tf_rip == (long)doreti_iret) {
					frame->tf_rip = (long)doreti_iret_fault;
					goto out2;
				}
			}
			break;

		case T_TSSFLT:
			/*
			 * PSL_NT can be set in user mode and isn't cleared
			 * automatically when the kernel is entered.  This
			 * causes a TSS fault when the kernel attempts to
			 * `iret' because the TSS link is uninitialized.  We
			 * want to get this fault so that we can fix the
			 * problem here and not every time the kernel is
			 * entered.
			 */
			if (frame->tf_rflags & PSL_NT) {
				frame->tf_rflags &= ~PSL_NT;
#if 0
				/* do we need this? */
				if (frame->tf_rip == (long)doreti_iret)
					frame->tf_rip = (long)doreti_iret_fault;
#endif
				goto out2;
			}
			break;

		case T_TRCTRAP:	 /* trace trap */
			/*
			 * Detect historical CPU artifact on syscall or int $3
			 * entry (if not shortcutted in exception.s via
			 * DIRECT_DISALLOW_SS_CPUBUG).
			 */
			gd->gd_cnt.v_trap++;
			if (frame->tf_rip == (register_t)IDTVEC(fast_syscall)) {
				krateprintf(&sscpubugrate,
					"Caught #DB at syscall cpu artifact\n");
				goto out2;
			}
			if (frame->tf_rip == (register_t)IDTVEC(bpt)) {
				krateprintf(&sscpubugrate,
					"Caught #DB at int $N cpu artifact\n");
				goto out2;
			}

			/*
			 * Ignore debug register trace traps due to
			 * accesses in the user's address space, which
			 * can happen under several conditions such as
			 * if a user sets a watchpoint on a buffer and
			 * then passes that buffer to a system call.
			 * We still want to get TRCTRAPS for addresses
			 * in kernel space because that is useful when
			 * debugging the kernel.
			 */
			if (user_dbreg_trap()) {
				/*
				 * Reset breakpoint bits because the
				 * processor doesn't
				 */
				load_dr6(rdr6() & ~0xf);
				goto out2;
			}
			/*
			 * FALLTHROUGH (TRCTRAP kernel mode, kernel address)
			 */
		case T_BPTFLT:
			/*
			 * If DDB is enabled, let it handle the debugger trap.
			 * Otherwise, debugger traps "can't happen".
			 */
			ucode = TRAP_BRKPT;
#ifdef DDB
			if (kdb_trap(type, 0, frame))
				goto out2;
#endif
			break;

#if NISA > 0
		case T_NMI:
			/* machine/parity/power fail/"kitchen sink" faults */
			if (isa_nmi(code) == 0) {
#ifdef DDB
				/*
				 * NMI can be hooked up to a pushbutton
				 * for debugging.
				 */
				if (ddb_on_nmi) {
					kprintf ("NMI ... going to debugger\n");
					kdb_trap(type, 0, frame);
				}
#endif /* DDB */
				goto out2;
			} else if (panic_on_nmi == 0)
				goto out2;
			/* FALL THROUGH */
#endif /* NISA > 0 */
		}
		trap_fatal(frame, 0);
		goto out2;
	}

	/*
	 * Fault from user mode, virtual kernel interecept.
	 *
	 * If the fault is directly related to a VM context managed by a
	 * virtual kernel then let the virtual kernel handle it.
	 */
	if (lp->lwp_vkernel && lp->lwp_vkernel->ve) {
		vkernel_trap(lp, frame);
		goto out;
	}

	/* Translate fault for emulators (e.g. Linux) */
	if (*p->p_sysent->sv_transtrap)
		i = (*p->p_sysent->sv_transtrap)(i, type);

	gd->gd_cnt.v_trap++;
	trapsignal(lp, i, ucode);

#ifdef DEBUG
	if (type <= MAX_TRAP_MSG) {
		uprintf("fatal process exception: %s",
			trap_msg[type]);
		if ((type == T_PAGEFLT) || (type == T_PROTFLT))
			uprintf(", fault VA = 0x%lx", frame->tf_addr);
		uprintf("\n");
	}
#endif

out:
	userret(lp, frame, sticks);
	userexit(lp);
out2:	;
	if (p != NULL && lp != NULL)
		KTR_LOG(kernentry_trap_ret, p->p_pid, lp->lwp_tid);
#ifdef INVARIANTS
	KASSERT(crit_count == td->td_critcount,
		("trap: critical section count mismatch! %d/%d",
		crit_count, td->td_pri));
	KASSERT(curstop == td->td_toks_stop,
		("trap: extra tokens held after trap! %ld/%ld",
		curstop - &td->td_toks_base,
		td->td_toks_stop - &td->td_toks_base));
#endif
}
Exemplo n.º 4
0
void
trap(struct trapframe *frame)
{
	struct globaldata *gd = mycpu;
	struct thread *td = gd->gd_curthread;
	struct lwp *lp = td->td_lwp;
	struct proc *p;
	int sticks = 0;
	int i = 0, ucode = 0, type, code;
	int have_mplock = 0;
#ifdef INVARIANTS
	int crit_count = td->td_critcount;
	lwkt_tokref_t curstop = td->td_toks_stop;
#endif
	vm_offset_t eva;

	p = td->td_proc;
#ifdef DDB
	/*
	 * We need to allow T_DNA faults when the debugger is active since
	 * some dumping paths do large bcopy() which use the floating
	 * point registers for faster copying.
	 */
	if (db_active && frame->tf_trapno != T_DNA) {
		eva = (frame->tf_trapno == T_PAGEFLT ? rcr2() : 0);
		++gd->gd_trap_nesting_level;
		MAKEMPSAFE(have_mplock);
		trap_fatal(frame, eva);
		--gd->gd_trap_nesting_level;
		goto out2;
	}
#endif

	eva = 0;
	++gd->gd_trap_nesting_level;
	if (frame->tf_trapno == T_PAGEFLT) {
		/*
		 * For some Cyrix CPUs, %cr2 is clobbered by interrupts.
		 * This problem is worked around by using an interrupt
		 * gate for the pagefault handler.  We are finally ready
		 * to read %cr2 and then must reenable interrupts.
		 *
		 * XXX this should be in the switch statement, but the
		 * NO_FOOF_HACK and VM86 goto and ifdefs obfuscate the
		 * flow of control too much for this to be obviously
		 * correct.
		 */
		eva = rcr2();
		cpu_enable_intr();
	}

	--gd->gd_trap_nesting_level;

	if (!(frame->tf_eflags & PSL_I)) {
		/*
		 * Buggy application or kernel code has disabled interrupts
		 * and then trapped.  Enabling interrupts now is wrong, but
		 * it is better than running with interrupts disabled until
		 * they are accidentally enabled later.
		 */
		type = frame->tf_trapno;
		if (ISPL(frame->tf_cs)==SEL_UPL || (frame->tf_eflags & PSL_VM)) {
			MAKEMPSAFE(have_mplock);
			kprintf(
			    "pid %ld (%s): trap %d with interrupts disabled\n",
			    (long)curproc->p_pid, curproc->p_comm, type);
		} else if (type != T_BPTFLT && type != T_TRCTRAP) {
			/*
			 * XXX not quite right, since this may be for a
			 * multiple fault in user mode.
			 */
			MAKEMPSAFE(have_mplock);
			kprintf("kernel trap %d with interrupts disabled\n",
			    type);
		}
		cpu_enable_intr();
	}

#if defined(I586_CPU) && !defined(NO_F00F_HACK)
restart:
#endif
	type = frame->tf_trapno;
	code = frame->tf_err;

	if (in_vm86call) {
		if (frame->tf_eflags & PSL_VM &&
		    (type == T_PROTFLT || type == T_STKFLT)) {
			KKASSERT(get_mplock_count(curthread) > 0);
			i = vm86_emulate((struct vm86frame *)frame);
			KKASSERT(get_mplock_count(curthread) > 0);
			if (i != 0) {
				/*
				 * returns to original process
				 */
				vm86_trap((struct vm86frame *)frame,
					  have_mplock);
				KKASSERT(0); /* NOT REACHED */
			}
			goto out2;
		}
		switch (type) {
			/*
			 * these traps want either a process context, or
			 * assume a normal userspace trap.
			 */
		case T_PROTFLT:
		case T_SEGNPFLT:
			trap_fatal(frame, eva);
			goto out2;
		case T_TRCTRAP:
			type = T_BPTFLT;	/* kernel breakpoint */
			/* FALL THROUGH */
		}
		goto kernel_trap;	/* normal kernel trap handling */
	}

        if ((ISPL(frame->tf_cs) == SEL_UPL) || (frame->tf_eflags & PSL_VM)) {
		/* user trap */

		KTR_LOG(kernentry_trap, p->p_pid, lp->lwp_tid,
			frame->tf_trapno, eva);

		userenter(td, p);

		sticks = (int)td->td_sticks;
		lp->lwp_md.md_regs = frame;

		switch (type) {
		case T_PRIVINFLT:	/* privileged instruction fault */
			i = SIGILL;
			ucode = ILL_PRVOPC;
			break;

		case T_BPTFLT:		/* bpt instruction fault */
		case T_TRCTRAP:		/* trace trap */
			frame->tf_eflags &= ~PSL_T;
			i = SIGTRAP;
			ucode = (type == T_TRCTRAP ? TRAP_TRACE : TRAP_BRKPT);
			break;

		case T_ARITHTRAP:	/* arithmetic trap */
			ucode = code;
			i = SIGFPE;
			break;

		case T_ASTFLT:		/* Allow process switch */
			mycpu->gd_cnt.v_soft++;
			if (mycpu->gd_reqflags & RQF_AST_OWEUPC) {
				atomic_clear_int(&mycpu->gd_reqflags,
						 RQF_AST_OWEUPC);
				addupc_task(p, p->p_prof.pr_addr,
					    p->p_prof.pr_ticks);
			}
			goto out;

			/*
			 * The following two traps can happen in
			 * vm86 mode, and, if so, we want to handle
			 * them specially.
			 */
		case T_PROTFLT:		/* general protection fault */
		case T_STKFLT:		/* stack fault */
			if (frame->tf_eflags & PSL_VM) {
				i = vm86_emulate((struct vm86frame *)frame);
				if (i == 0)
					goto out;
				break;
			}
			i = SIGBUS;
			ucode = (type == T_PROTFLT) ? BUS_OBJERR : BUS_ADRERR;
			break;
		case T_SEGNPFLT:	/* segment not present fault */
			i = SIGBUS;
			ucode = BUS_ADRERR;
			break;
		case T_TSSFLT:		/* invalid TSS fault */
		case T_DOUBLEFLT:	/* double fault */
		default:
			i = SIGBUS;
			ucode = BUS_OBJERR;
			break;

		case T_PAGEFLT:		/* page fault */
			i = trap_pfault(frame, TRUE, eva);
			if (i == -1)
				goto out;
#if defined(I586_CPU) && !defined(NO_F00F_HACK)
			if (i == -2)
				goto restart;
#endif
			if (i == 0)
				goto out;

			if (i == SIGSEGV)
				ucode = SEGV_MAPERR;
			else {
				i = SIGSEGV;
				ucode = SEGV_ACCERR;
			}
			break;

		case T_DIVIDE:		/* integer divide fault */
			ucode = FPE_INTDIV;
			i = SIGFPE;
			break;

#if NISA > 0
		case T_NMI:
			MAKEMPSAFE(have_mplock);
#ifdef POWERFAIL_NMI
			goto handle_powerfail;
#else /* !POWERFAIL_NMI */
			/* machine/parity/power fail/"kitchen sink" faults */
			if (isa_nmi(code) == 0) {
#ifdef DDB
				/*
				 * NMI can be hooked up to a pushbutton
				 * for debugging.
				 */
				if (ddb_on_nmi) {
					kprintf ("NMI ... going to debugger\n");
					kdb_trap (type, 0, frame);
				}
#endif /* DDB */
				goto out2;
			} else if (panic_on_nmi)
				panic("NMI indicates hardware failure");
			break;
#endif /* POWERFAIL_NMI */
#endif /* NISA > 0 */

		case T_OFLOW:		/* integer overflow fault */
			ucode = FPE_INTOVF;
			i = SIGFPE;
			break;

		case T_BOUND:		/* bounds check fault */
			ucode = FPE_FLTSUB;
			i = SIGFPE;
			break;

		case T_DNA:
			/*
			 * Virtual kernel intercept - pass the DNA exception
			 * to the virtual kernel if it asked to handle it.
			 * This occurs when the virtual kernel is holding
			 * onto the FP context for a different emulated
			 * process then the one currently running.
			 *
			 * We must still call npxdna() since we may have
			 * saved FP state that the virtual kernel needs
			 * to hand over to a different emulated process.
			 */
			if (lp->lwp_vkernel && lp->lwp_vkernel->ve &&
			    (td->td_pcb->pcb_flags & FP_VIRTFP)
			) {
				npxdna();
				break;
			}

#if NNPX > 0
			/* 
			 * The kernel may have switched out the FP unit's
			 * state, causing the user process to take a fault
			 * when it tries to use the FP unit.  Restore the
			 * state here
			 */
			if (npxdna())
				goto out;
#endif
			if (!pmath_emulate) {
				i = SIGFPE;
				ucode = FPE_FPU_NP_TRAP;
				break;
			}
			i = (*pmath_emulate)(frame);
			if (i == 0) {
				if (!(frame->tf_eflags & PSL_T))
					goto out2;
				frame->tf_eflags &= ~PSL_T;
				i = SIGTRAP;
			}
			/* else ucode = emulator_only_knows() XXX */
			break;

		case T_FPOPFLT:		/* FPU operand fetch fault */
			ucode = ILL_COPROC;
			i = SIGILL;
			break;

		case T_XMMFLT:		/* SIMD floating-point exception */
			ucode = 0; /* XXX */
			i = SIGFPE;
			break;
		}
	} else {
kernel_trap:
		/* kernel trap */

		switch (type) {
		case T_PAGEFLT:			/* page fault */
			trap_pfault(frame, FALSE, eva);
			goto out2;

		case T_DNA:
#if NNPX > 0
			/*
			 * The kernel may be using npx for copying or other
			 * purposes.
			 */
			if (npxdna())
				goto out2;
#endif
			break;

		case T_PROTFLT:		/* general protection fault */
		case T_SEGNPFLT:	/* segment not present fault */
			/*
			 * Invalid segment selectors and out of bounds
			 * %eip's and %esp's can be set up in user mode.
			 * This causes a fault in kernel mode when the
			 * kernel tries to return to user mode.  We want
			 * to get this fault so that we can fix the
			 * problem here and not have to check all the
			 * selectors and pointers when the user changes
			 * them.
			 */
#define	MAYBE_DORETI_FAULT(where, whereto)				\
	do {								\
		if (frame->tf_eip == (int)where) {			\
			frame->tf_eip = (int)whereto;			\
			goto out2;					\
		}							\
	} while (0)
			if (mycpu->gd_intr_nesting_level == 0) {
				/*
				 * Invalid %fs's and %gs's can be created using
				 * procfs or PT_SETREGS or by invalidating the
				 * underlying LDT entry.  This causes a fault
				 * in kernel mode when the kernel attempts to
				 * switch contexts.  Lose the bad context
				 * (XXX) so that we can continue, and generate
				 * a signal.
				 */
				MAYBE_DORETI_FAULT(doreti_iret,
						   doreti_iret_fault);
				MAYBE_DORETI_FAULT(doreti_popl_ds,
						   doreti_popl_ds_fault);
				MAYBE_DORETI_FAULT(doreti_popl_es,
						   doreti_popl_es_fault);
				MAYBE_DORETI_FAULT(doreti_popl_fs,
						   doreti_popl_fs_fault);
				MAYBE_DORETI_FAULT(doreti_popl_gs,
						   doreti_popl_gs_fault);

				/*
				 * NOTE: cpu doesn't push esp on kernel trap
				 */
				if (td->td_pcb->pcb_onfault &&
				    td->td_pcb->pcb_onfault_sp ==
				    (int)&frame->tf_esp) {
					frame->tf_eip = 
					    (register_t)td->td_pcb->pcb_onfault;
					goto out2;
				}
			}
			break;

		case T_TSSFLT:
			/*
			 * PSL_NT can be set in user mode and isn't cleared
			 * automatically when the kernel is entered.  This
			 * causes a TSS fault when the kernel attempts to
			 * `iret' because the TSS link is uninitialized.  We
			 * want to get this fault so that we can fix the
			 * problem here and not every time the kernel is
			 * entered.
			 */
			if (frame->tf_eflags & PSL_NT) {
				frame->tf_eflags &= ~PSL_NT;
				goto out2;
			}
			break;

		case T_TRCTRAP:	 /* trace trap */
			if (frame->tf_eip == (int)IDTVEC(syscall)) {
				/*
				 * We've just entered system mode via the
				 * syscall lcall.  Continue single stepping
				 * silently until the syscall handler has
				 * saved the flags.
				 */
				goto out2;
			}
			if (frame->tf_eip == (int)IDTVEC(syscall) + 1) {
				/*
				 * The syscall handler has now saved the
				 * flags.  Stop single stepping it.
				 */
				frame->tf_eflags &= ~PSL_T;
				goto out2;
			}
                        /*
                         * Ignore debug register trace traps due to
                         * accesses in the user's address space, which
                         * can happen under several conditions such as
                         * if a user sets a watchpoint on a buffer and
                         * then passes that buffer to a system call.
                         * We still want to get TRCTRAPS for addresses
                         * in kernel space because that is useful when
                         * debugging the kernel.
                         */
                        if (user_dbreg_trap()) {
                                /*
                                 * Reset breakpoint bits because the
                                 * processor doesn't
                                 */
                                load_dr6(rdr6() & 0xfffffff0);
                                goto out2;
                        }
			/*
			 * FALLTHROUGH (TRCTRAP kernel mode, kernel address)
			 */
		case T_BPTFLT:
			/*
			 * If DDB is enabled, let it handle the debugger trap.
			 * Otherwise, debugger traps "can't happen".
			 */
			ucode = TRAP_BRKPT;
#ifdef DDB
			MAKEMPSAFE(have_mplock);
			if (kdb_trap (type, 0, frame))
				goto out2;
#endif
			break;

#if NISA > 0
		case T_NMI:
			MAKEMPSAFE(have_mplock);
#ifdef POWERFAIL_NMI
#ifndef TIMER_FREQ
#  define TIMER_FREQ 1193182
#endif
	handle_powerfail:
		{
		  static unsigned lastalert = 0;

		  if (time_uptime - lastalert > 10) {
		      log(LOG_WARNING, "NMI: power fail\n");
		      sysbeep(TIMER_FREQ/880, hz);
		      lastalert = time_uptime;
		  }
		    /* YYY mp count */
		  goto out2;
		}
#else /* !POWERFAIL_NMI */
			/* machine/parity/power fail/"kitchen sink" faults */
			if (isa_nmi(code) == 0) {
#ifdef DDB
				/*
				 * NMI can be hooked up to a pushbutton
				 * for debugging.
				 */
				if (ddb_on_nmi) {
					kprintf ("NMI ... going to debugger\n");
					kdb_trap (type, 0, frame);
				}
#endif /* DDB */
				goto out2;
			} else if (panic_on_nmi == 0)
				goto out2;
			/* FALL THROUGH */
#endif /* POWERFAIL_NMI */
#endif /* NISA > 0 */
		}

		MAKEMPSAFE(have_mplock);
		trap_fatal(frame, eva);
		goto out2;
	}

	/*
	 * Virtual kernel intercept - if the fault is directly related to a
	 * VM context managed by a virtual kernel then let the virtual kernel
	 * handle it.
	 */
	if (lp->lwp_vkernel && lp->lwp_vkernel->ve) {
		vkernel_trap(lp, frame);
		goto out;
	}

	/* Translate fault for emulators (e.g. Linux) */
	if (*p->p_sysent->sv_transtrap)
		i = (*p->p_sysent->sv_transtrap)(i, type);

	MAKEMPSAFE(have_mplock);
	trapsignal(lp, i, ucode);

#ifdef DEBUG
	if (type <= MAX_TRAP_MSG) {
		uprintf("fatal process exception: %s",
			trap_msg[type]);
		if ((type == T_PAGEFLT) || (type == T_PROTFLT))
			uprintf(", fault VA = 0x%lx", (u_long)eva);
		uprintf("\n");
	}
#endif

out:
	userret(lp, frame, sticks);
	userexit(lp);
out2:	;
	if (have_mplock)
		rel_mplock();
	if (p != NULL && lp != NULL)
		KTR_LOG(kernentry_trap_ret, p->p_pid, lp->lwp_tid);
#ifdef INVARIANTS
	KASSERT(crit_count == td->td_critcount,
		("trap: critical section count mismatch! %d/%d",
		crit_count, td->td_pri));
	KASSERT(curstop == td->td_toks_stop,
		("trap: extra tokens held after trap! %zd/%zd",
		curstop - &td->td_toks_base,
		td->td_toks_stop - &td->td_toks_base));
#endif
}
Exemplo n.º 5
0
void
trap(struct trapframe *frame)
{
	struct thread *td = curthread;
	struct proc *p = td->td_proc;
	int i = 0, ucode = 0, code;
	u_int type;
	register_t addr = 0;
	ksiginfo_t ksi;

	PCPU_INC(cnt.v_trap);
	type = frame->tf_trapno;

#ifdef SMP
#ifdef STOP_NMI
	/* Handler for NMI IPIs used for stopping CPUs. */
	if (type == T_NMI) {
	         if (ipi_nmi_handler() == 0)
	                   goto out;
	}
#endif /* STOP_NMI */
#endif /* SMP */

#ifdef KDB
	if (kdb_active) {
		kdb_reenter();
		goto out;
	}
#endif

#ifdef	HWPMC_HOOKS
	/*
	 * CPU PMCs interrupt using an NMI.  If the PMC module is
	 * active, pass the 'rip' value to the PMC module's interrupt
	 * handler.  A return value of '1' from the handler means that
	 * the NMI was handled by it and we can return immediately.
	 */
	if (type == T_NMI && pmc_intr &&
	    (*pmc_intr)(PCPU_GET(cpuid), frame))
		goto out;
#endif

	if (type == T_MCHK) {
		if (!mca_intr())
			trap_fatal(frame, 0);
		goto out;
	}

#ifdef KDTRACE_HOOKS
	/*
	 * A trap can occur while DTrace executes a probe. Before
	 * executing the probe, DTrace blocks re-scheduling and sets
	 * a flag in it's per-cpu flags to indicate that it doesn't
	 * want to fault. On returning from the the probe, the no-fault
	 * flag is cleared and finally re-scheduling is enabled.
	 *
	 * If the DTrace kernel module has registered a trap handler,
	 * call it and if it returns non-zero, assume that it has
	 * handled the trap and modified the trap frame so that this
	 * function can return normally.
	 */
	if (dtrace_trap_func != NULL)
		if ((*dtrace_trap_func)(frame, type))
			goto out;
#endif

	if ((frame->tf_rflags & PSL_I) == 0) {
		/*
		 * Buggy application or kernel code has disabled
		 * interrupts and then trapped.  Enabling interrupts
		 * now is wrong, but it is better than running with
		 * interrupts disabled until they are accidentally
		 * enabled later.
		 */
		if (ISPL(frame->tf_cs) == SEL_UPL)
			printf(
			    "pid %ld (%s): trap %d with interrupts disabled\n",
			    (long)curproc->p_pid, curproc->p_comm, type);
		else if (type != T_NMI && type != T_BPTFLT &&
		    type != T_TRCTRAP) {
			/*
			 * XXX not quite right, since this may be for a
			 * multiple fault in user mode.
			 */
			printf("kernel trap %d with interrupts disabled\n",
			    type);
			/*
			 * We shouldn't enable interrupts while holding a
			 * spin lock or servicing an NMI.
			 */
			if (type != T_NMI && td->td_md.md_spinlock_count == 0)
				enable_intr();
		}
	}

	code = frame->tf_err;
	if (type == T_PAGEFLT) {
		/*
		 * If we get a page fault while in a critical section, then
		 * it is most likely a fatal kernel page fault.  The kernel
		 * is already going to panic trying to get a sleep lock to
		 * do the VM lookup, so just consider it a fatal trap so the
		 * kernel can print out a useful trap message and even get
		 * to the debugger.
		 *
		 * If we get a page fault while holding a non-sleepable
		 * lock, then it is most likely a fatal kernel page fault.
		 * If WITNESS is enabled, then it's going to whine about
		 * bogus LORs with various VM locks, so just skip to the
		 * fatal trap handling directly.
		 */
		if (td->td_critnest != 0 ||
		    WITNESS_CHECK(WARN_SLEEPOK | WARN_GIANTOK, NULL,
		    "Kernel page fault") != 0)
			trap_fatal(frame, frame->tf_addr);
	}

        if (ISPL(frame->tf_cs) == SEL_UPL) {
		/* user trap */

		td->td_pticks = 0;
		td->td_frame = frame;
		addr = frame->tf_rip;
		if (td->td_ucred != p->p_ucred) 
			cred_update_thread(td);

		switch (type) {
		case T_PRIVINFLT:	/* privileged instruction fault */
			i = SIGILL;
			ucode = ILL_PRVOPC;
			break;

		case T_BPTFLT:		/* bpt instruction fault */
		case T_TRCTRAP:		/* trace trap */
			enable_intr();
			frame->tf_rflags &= ~PSL_T;
			i = SIGTRAP;
			ucode = (type == T_TRCTRAP ? TRAP_TRACE : TRAP_BRKPT);
			break;

		case T_ARITHTRAP:	/* arithmetic trap */
			ucode = fputrap();
			if (ucode == -1)
				goto userout;
			i = SIGFPE;
			break;

		case T_PROTFLT:		/* general protection fault */
			i = SIGBUS;
			ucode = BUS_OBJERR;
			break;
		case T_STKFLT:		/* stack fault */
		case T_SEGNPFLT:	/* segment not present fault */
			i = SIGBUS;
			ucode = BUS_ADRERR;
			break;
		case T_TSSFLT:		/* invalid TSS fault */
			i = SIGBUS;
			ucode = BUS_OBJERR;
			break;
		case T_DOUBLEFLT:	/* double fault */
		default:
			i = SIGBUS;
			ucode = BUS_OBJERR;
			break;

		case T_PAGEFLT:		/* page fault */
			addr = frame->tf_addr;
#ifdef KSE
			if (td->td_pflags & TDP_SA)
				thread_user_enter(td);
#endif
			i = trap_pfault(frame, TRUE);
			if (i == -1)
				goto userout;
			if (i == 0)
				goto user;

			if (i == SIGSEGV)
				ucode = SEGV_MAPERR;
			else {
				if (prot_fault_translation == 0) {
					/*
					 * Autodetect.
					 * This check also covers the images
					 * without the ABI-tag ELF note.
					 */
					if ((curproc->p_sysent ==
					    &elf64_freebsd_sysvec
#ifdef COMPAT_IA32
					    || curproc->p_sysent ==
					    &ia32_freebsd_sysvec
#endif
					    ) && p->p_osrel >= 700004) {
						i = SIGSEGV;
						ucode = SEGV_ACCERR;
					} else {
						i = SIGBUS;
						ucode = BUS_PAGE_FAULT;
					}
				} else if (prot_fault_translation == 1) {
					/*
					 * Always compat mode.
					 */
					i = SIGBUS;
					ucode = BUS_PAGE_FAULT;
				} else {
					/*
					 * Always SIGSEGV mode.
					 */
					i = SIGSEGV;
					ucode = SEGV_ACCERR;
				}
			}
			break;

		case T_DIVIDE:		/* integer divide fault */
			ucode = FPE_INTDIV;
			i = SIGFPE;
			break;

#ifdef DEV_ISA
		case T_NMI:
			/* machine/parity/power fail/"kitchen sink" faults */
			/* XXX Giant */
			if (isa_nmi(code) == 0) {
#ifdef KDB
				/*
				 * NMI can be hooked up to a pushbutton
				 * for debugging.
				 */
				if (kdb_on_nmi) {
					printf ("NMI ... going to debugger\n");
					kdb_trap(type, 0, frame);
				}
#endif /* KDB */
				goto userout;
			} else if (panic_on_nmi)
				panic("NMI indicates hardware failure");
			break;
#endif /* DEV_ISA */

		case T_OFLOW:		/* integer overflow fault */
			ucode = FPE_INTOVF;
			i = SIGFPE;
			break;

		case T_BOUND:		/* bounds check fault */
			ucode = FPE_FLTSUB;
			i = SIGFPE;
			break;

		case T_DNA:
			/* transparent fault (due to context switch "late") */
			fpudna();
			goto userout;

		case T_FPOPFLT:		/* FPU operand fetch fault */
			ucode = ILL_COPROC;
			i = SIGILL;
			break;

		case T_XMMFLT:		/* SIMD floating-point exception */
			ucode = 0; /* XXX */
			i = SIGFPE;
			break;
		}
	} else {
		/* kernel trap */

		KASSERT(cold || td->td_ucred != NULL,
		    ("kernel trap doesn't have ucred"));
		switch (type) {
		case T_PAGEFLT:			/* page fault */
			(void) trap_pfault(frame, FALSE);
			goto out;

		case T_DNA:
			/*
			 * The kernel is apparently using fpu for copying.
			 * XXX this should be fatal unless the kernel has
			 * registered such use.
			 */
			fpudna();
			printf("fpudna in kernel mode!\n");
			goto out;

		case T_STKFLT:		/* stack fault */
			break;

		case T_PROTFLT:		/* general protection fault */
		case T_SEGNPFLT:	/* segment not present fault */
			if (td->td_intr_nesting_level != 0)
				break;

			/*
			 * Invalid segment selectors and out of bounds
			 * %rip's and %rsp's can be set up in user mode.
			 * This causes a fault in kernel mode when the
			 * kernel tries to return to user mode.  We want
			 * to get this fault so that we can fix the
			 * problem here and not have to check all the
			 * selectors and pointers when the user changes
			 * them.
			 */
			if (frame->tf_rip == (long)doreti_iret) {
				frame->tf_rip = (long)doreti_iret_fault;
				goto out;
			}
			if (PCPU_GET(curpcb)->pcb_onfault != NULL) {
				frame->tf_rip =
				    (long)PCPU_GET(curpcb)->pcb_onfault;
				goto out;
			}
			break;

		case T_TSSFLT:
			/*
			 * PSL_NT can be set in user mode and isn't cleared
			 * automatically when the kernel is entered.  This
			 * causes a TSS fault when the kernel attempts to
			 * `iret' because the TSS link is uninitialized.  We
			 * want to get this fault so that we can fix the
			 * problem here and not every time the kernel is
			 * entered.
			 */
			if (frame->tf_rflags & PSL_NT) {
				frame->tf_rflags &= ~PSL_NT;
				goto out;
			}
			break;

		case T_TRCTRAP:	 /* trace trap */
			/*
			 * Ignore debug register trace traps due to
			 * accesses in the user's address space, which
			 * can happen under several conditions such as
			 * if a user sets a watchpoint on a buffer and
			 * then passes that buffer to a system call.
			 * We still want to get TRCTRAPS for addresses
			 * in kernel space because that is useful when
			 * debugging the kernel.
			 */
			if (user_dbreg_trap()) {
				/*
				 * Reset breakpoint bits because the
				 * processor doesn't
				 */
				/* XXX check upper bits here */
				load_dr6(rdr6() & 0xfffffff0);
				goto out;
			}
			/*
			 * FALLTHROUGH (TRCTRAP kernel mode, kernel address)
			 */
		case T_BPTFLT:
			/*
			 * If KDB is enabled, let it handle the debugger trap.
			 * Otherwise, debugger traps "can't happen".
			 */
#ifdef KDB
			if (kdb_trap(type, 0, frame))
				goto out;
#endif
			break;

#ifdef DEV_ISA
		case T_NMI:
			/* XXX Giant */
			/* machine/parity/power fail/"kitchen sink" faults */
			if (isa_nmi(code) == 0) {
#ifdef KDB
				/*
				 * NMI can be hooked up to a pushbutton
				 * for debugging.
				 */
				if (kdb_on_nmi) {
					printf ("NMI ... going to debugger\n");
					kdb_trap(type, 0, frame);
				}
#endif /* KDB */
				goto out;
			} else if (panic_on_nmi == 0)
				goto out;
			/* FALLTHROUGH */
#endif /* DEV_ISA */
		}

		trap_fatal(frame, 0);
		goto out;
	}

	/* Translate fault for emulators (e.g. Linux) */
	if (*p->p_sysent->sv_transtrap)
		i = (*p->p_sysent->sv_transtrap)(i, type);

	ksiginfo_init_trap(&ksi);
	ksi.ksi_signo = i;
	ksi.ksi_code = ucode;
	ksi.ksi_trapno = type;
	ksi.ksi_addr = (void *)addr;
	trapsignal(td, &ksi);

#ifdef DEBUG
	if (type <= MAX_TRAP_MSG) {
		uprintf("fatal process exception: %s",
			trap_msg[type]);
		if ((type == T_PAGEFLT) || (type == T_PROTFLT))
			uprintf(", fault VA = 0x%lx", frame->tf_addr);
		uprintf("\n");
	}
#endif

user:
	userret(td, frame);
	mtx_assert(&Giant, MA_NOTOWNED);
userout:
out:
	return;
}
Exemplo n.º 6
0
void
user_trap(struct trapframe *frame)
{
	struct globaldata *gd = mycpu;
	struct thread *td = gd->gd_curthread;
	struct lwp *lp = td->td_lwp;
	struct proc *p;
	int sticks = 0;
	int i = 0, ucode = 0, type, code;
	int have_mplock = 0;
#ifdef INVARIANTS
	int crit_count = td->td_critcount;
	lwkt_tokref_t curstop = td->td_toks_stop;
#endif
	vm_offset_t eva;

	p = td->td_proc;

	/*
	 * This is a bad kludge to avoid changing the various trapframe
	 * structures.  Because we are enabled as a virtual kernel,
	 * the original tf_err field will be passed to us shifted 16
	 * over in the tf_trapno field for T_PAGEFLT.
	 */
	if (frame->tf_trapno == T_PAGEFLT)
		eva = frame->tf_err;
	else
		eva = 0;
#if 0
	kprintf("USER_TRAP AT %08x xflags %d trapno %d eva %08x\n", 
		frame->tf_eip, frame->tf_xflags, frame->tf_trapno, eva);
#endif

	/*
	 * Everything coming from user mode runs through user_trap,
	 * including system calls.
	 */
	if (frame->tf_trapno == T_SYSCALL80) {
		syscall2(frame);
		return;
	}

	KTR_LOG(kernentry_trap, lp->lwp_proc->p_pid, lp->lwp_tid,
		frame->tf_trapno, eva);

#ifdef DDB
	if (db_active) {
		eva = (frame->tf_trapno == T_PAGEFLT ? rcr2() : 0);
		++gd->gd_trap_nesting_level;
		MAKEMPSAFE(have_mplock);
		trap_fatal(frame, TRUE, eva);
		--gd->gd_trap_nesting_level;
		goto out2;
	}
#endif

#if defined(I586_CPU) && !defined(NO_F00F_HACK)
restart:
#endif
	type = frame->tf_trapno;
	code = frame->tf_err;

	userenter(td, p);

	sticks = (int)td->td_sticks;
	lp->lwp_md.md_regs = frame;

	switch (type) {
	case T_PRIVINFLT:	/* privileged instruction fault */
		i = SIGILL;
		ucode = ILL_PRVOPC;
		break;

	case T_BPTFLT:		/* bpt instruction fault */
	case T_TRCTRAP:		/* trace trap */
		frame->tf_eflags &= ~PSL_T;
		i = SIGTRAP;
		ucode = (type == T_TRCTRAP ? TRAP_TRACE : TRAP_BRKPT);
		break;

	case T_ARITHTRAP:	/* arithmetic trap */
		ucode = code;
		i = SIGFPE;
		break;

	case T_ASTFLT:		/* Allow process switch */
		mycpu->gd_cnt.v_soft++;
		if (mycpu->gd_reqflags & RQF_AST_OWEUPC) {
			atomic_clear_int(&mycpu->gd_reqflags,
				    RQF_AST_OWEUPC);
			addupc_task(p, p->p_prof.pr_addr,
				    p->p_prof.pr_ticks);
		}
		goto out;

		/*
		 * The following two traps can happen in
		 * vm86 mode, and, if so, we want to handle
		 * them specially.
		 */
	case T_PROTFLT:		/* general protection fault */
	case T_STKFLT:		/* stack fault */
#if 0
		if (frame->tf_eflags & PSL_VM) {
			i = vm86_emulate((struct vm86frame *)frame);
			if (i == 0)
				goto out;
			break;
		}
#endif
		i = SIGBUS;
		ucode = (type == T_PROTFLT) ? BUS_OBJERR : BUS_ADRERR;
		break;
	case T_SEGNPFLT:	/* segment not present fault */
		i = SIGBUS;
		ucode = BUS_ADRERR;
		break;
	case T_TSSFLT:		/* invalid TSS fault */
	case T_DOUBLEFLT:	/* double fault */
	default:
		i = SIGBUS;
		ucode = BUS_OBJERR;
		break;

	case T_PAGEFLT:		/* page fault */
		MAKEMPSAFE(have_mplock);
		i = trap_pfault(frame, TRUE, eva);
		if (i == -1)
			goto out;
#if defined(I586_CPU) && !defined(NO_F00F_HACK)
		if (i == -2)
			goto restart;
#endif
		if (i == 0)
			goto out;

		if (i == SIGSEGV)
			ucode = SEGV_MAPERR;
		else {
			i = SIGSEGV;
			ucode = SEGV_ACCERR;
		}
		break;

	case T_DIVIDE:		/* integer divide fault */
		ucode = FPE_INTDIV;
		i = SIGFPE;
		break;

#if NISA > 0
	case T_NMI:
		MAKEMPSAFE(have_mplock);
		/* machine/parity/power fail/"kitchen sink" faults */
		if (isa_nmi(code) == 0) {
#ifdef DDB
			/*
			 * NMI can be hooked up to a pushbutton
			 * for debugging.
			 */
			if (ddb_on_nmi) {
				kprintf ("NMI ... going to debugger\n");
				kdb_trap (type, 0, frame);
			}
#endif /* DDB */
			goto out2;
		} else if (panic_on_nmi)
			panic("NMI indicates hardware failure");
		break;
#endif /* NISA > 0 */

	case T_OFLOW:		/* integer overflow fault */
		ucode = FPE_INTOVF;
		i = SIGFPE;
		break;

	case T_BOUND:		/* bounds check fault */
		ucode = FPE_FLTSUB;
		i = SIGFPE;
		break;

	case T_DNA:
		/*
		 * Virtual kernel intercept - pass the DNA exception
		 * to the (emulated) virtual kernel if it asked to handle 
		 * it.  This occurs when the virtual kernel is holding
		 * onto the FP context for a different emulated
		 * process then the one currently running.
		 *
		 * We must still call npxdna() since we may have
		 * saved FP state that the (emulated) virtual kernel
		 * needs to hand over to a different emulated process.
		 */
		if (lp->lwp_vkernel && lp->lwp_vkernel->ve &&
		    (td->td_pcb->pcb_flags & FP_VIRTFP)
		) {
			npxdna(frame);
			break;
		}

#if NNPX > 0
		/* 
		 * The kernel may have switched out the FP unit's
		 * state, causing the user process to take a fault
		 * when it tries to use the FP unit.  Restore the
		 * state here
		 */
		if (npxdna(frame))
			goto out;
#endif
		if (!pmath_emulate) {
			i = SIGFPE;
			ucode = FPE_FPU_NP_TRAP;
			break;
		}
		i = (*pmath_emulate)(frame);
		if (i == 0) {
			if (!(frame->tf_eflags & PSL_T))
				goto out2;
			frame->tf_eflags &= ~PSL_T;
			i = SIGTRAP;
		}
		/* else ucode = emulator_only_knows() XXX */
		break;

	case T_FPOPFLT:		/* FPU operand fetch fault */
		ucode = ILL_COPROC;
		i = SIGILL;
		break;

	case T_XMMFLT:		/* SIMD floating-point exception */
		ucode = 0; /* XXX */
		i = SIGFPE;
		break;
	}

	/*
	 * Virtual kernel intercept - if the fault is directly related to a
	 * VM context managed by a virtual kernel then let the virtual kernel
	 * handle it.
	 */
	if (lp->lwp_vkernel && lp->lwp_vkernel->ve) {
		vkernel_trap(lp, frame);
		goto out;
	}

	/*
	 * Translate fault for emulators (e.g. Linux) 
	 */
	if (*p->p_sysent->sv_transtrap)
		i = (*p->p_sysent->sv_transtrap)(i, type);

	MAKEMPSAFE(have_mplock);
	trapsignal(lp, i, ucode);

#ifdef DEBUG
	if (type <= MAX_TRAP_MSG) {
		uprintf("fatal process exception: %s",
			trap_msg[type]);
		if ((type == T_PAGEFLT) || (type == T_PROTFLT))
			uprintf(", fault VA = 0x%lx", (u_long)eva);
		uprintf("\n");
	}
#endif

out:
	userret(lp, frame, sticks);
	userexit(lp);
out2:	;
	if (have_mplock)
		rel_mplock();
	KTR_LOG(kernentry_trap_ret, lp->lwp_proc->p_pid, lp->lwp_tid);
#ifdef INVARIANTS
	KASSERT(crit_count == td->td_critcount,
		("trap: critical section count mismatch! %d/%d",
		crit_count, td->td_pri));
	KASSERT(curstop == td->td_toks_stop,
		("trap: extra tokens held after trap! %zd/%zd",
		curstop - &td->td_toks_base,
		td->td_toks_stop - &td->td_toks_base));
#endif
}