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/*-
* Copyright (C) 1994, David Greenman
* Copyright (c) 1990, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* the University of Utah, and William Jolitz.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* from: @(#)trap.c 7.4 (Berkeley) 5/13/91
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD: release/9.1.0/sys/i386/i386/trap.c 236238 2012-05-29 14:50:21Z fabient $");
/*
* 386 Trap and System call handling
*/
#include "opt_clock.h"
#include "opt_cpu.h"
#include "opt_hwpmc_hooks.h"
#include "opt_isa.h"
#include "opt_kdb.h"
#include "opt_kdtrace.h"
#include "opt_npx.h"
#include "opt_trap.h"
#include <sys/param.h>
#include <sys/bus.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/pioctl.h>
#include <sys/ptrace.h>
#include <sys/kdb.h>
#include <sys/kernel.h>
#include <sys/ktr.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/resourcevar.h>
#include <sys/signalvar.h>
#include <sys/syscall.h>
#include <sys/sysctl.h>
#include <sys/sysent.h>
#include <sys/uio.h>
#include <sys/vmmeter.h>
#ifdef HWPMC_HOOKS
#include <sys/pmckern.h>
PMC_SOFT_DEFINE( , , page_fault, all);
PMC_SOFT_DEFINE( , , page_fault, read);
PMC_SOFT_DEFINE( , , page_fault, write);
#endif
#include <security/audit/audit.h>
#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/pmap.h>
#include <vm/vm_kern.h>
#include <vm/vm_map.h>
#include <vm/vm_page.h>
#include <vm/vm_extern.h>
#include <machine/cpu.h>
#include <machine/intr_machdep.h>
#include <x86/mca.h>
#include <machine/md_var.h>
#include <machine/pcb.h>
#ifdef SMP
#include <machine/smp.h>
#endif
#include <machine/tss.h>
#include <machine/vm86.h>
#ifdef POWERFAIL_NMI
#include <sys/syslog.h>
#include <machine/clock.h>
#endif
#ifdef KDTRACE_HOOKS
#include <sys/dtrace_bsd.h>
/*
* This is a hook which is initialised by the dtrace module
* to handle traps which might occur during DTrace probe
* execution.
*/
dtrace_trap_func_t dtrace_trap_func;
dtrace_doubletrap_func_t dtrace_doubletrap_func;
/*
* This is a hook which is initialised by the systrace module
* when it is loaded. This keeps the DTrace syscall provider
* implementation opaque.
*/
systrace_probe_func_t systrace_probe_func;
/*
* These hooks are necessary for the pid, usdt and fasttrap providers.
*/
dtrace_fasttrap_probe_ptr_t dtrace_fasttrap_probe_ptr;
dtrace_pid_probe_ptr_t dtrace_pid_probe_ptr;
dtrace_return_probe_ptr_t dtrace_return_probe_ptr;
#endif
extern void trap(struct trapframe *frame);
extern void syscall(struct trapframe *frame);
static int trap_pfault(struct trapframe *, int, vm_offset_t);
static void trap_fatal(struct trapframe *, vm_offset_t);
void dblfault_handler(void);
extern inthand_t IDTVEC(lcall_syscall);
#define MAX_TRAP_MSG 33
static char *trap_msg[] = {
"", /* 0 unused */
"privileged instruction fault", /* 1 T_PRIVINFLT */
"", /* 2 unused */
"breakpoint instruction fault", /* 3 T_BPTFLT */
"", /* 4 unused */
"", /* 5 unused */
"arithmetic trap", /* 6 T_ARITHTRAP */
"", /* 7 unused */
"", /* 8 unused */
"general protection fault", /* 9 T_PROTFLT */
"trace trap", /* 10 T_TRCTRAP */
"", /* 11 unused */
"page fault", /* 12 T_PAGEFLT */
"", /* 13 unused */
"alignment fault", /* 14 T_ALIGNFLT */
"", /* 15 unused */
"", /* 16 unused */
"", /* 17 unused */
"integer divide fault", /* 18 T_DIVIDE */
"non-maskable interrupt trap", /* 19 T_NMI */
"overflow trap", /* 20 T_OFLOW */
"FPU bounds check fault", /* 21 T_BOUND */
"FPU device not available", /* 22 T_DNA */
"double fault", /* 23 T_DOUBLEFLT */
"FPU operand fetch fault", /* 24 T_FPOPFLT */
"invalid TSS fault", /* 25 T_TSSFLT */
"segment not present fault", /* 26 T_SEGNPFLT */
"stack fault", /* 27 T_STKFLT */
"machine check trap", /* 28 T_MCHK */
"SIMD floating-point exception", /* 29 T_XMMFLT */
"reserved (unknown) fault", /* 30 T_RESERVED */
"", /* 31 unused (reserved) */
"DTrace pid return trap", /* 32 T_DTRACE_RET */
"DTrace fasttrap probe trap", /* 33 T_DTRACE_PROBE */
};
#if defined(I586_CPU) && !defined(NO_F00F_HACK)
extern int has_f00f_bug;
#endif
#ifdef KDB
static int kdb_on_nmi = 1;
SYSCTL_INT(_machdep, OID_AUTO, kdb_on_nmi, CTLFLAG_RW,
&kdb_on_nmi, 0, "Go to KDB on NMI");
TUNABLE_INT("machdep.kdb_on_nmi", &kdb_on_nmi);
#endif
static int panic_on_nmi = 1;
SYSCTL_INT(_machdep, OID_AUTO, panic_on_nmi, CTLFLAG_RW,
&panic_on_nmi, 0, "Panic on NMI");
TUNABLE_INT("machdep.panic_on_nmi", &panic_on_nmi);
static int prot_fault_translation = 0;
SYSCTL_INT(_machdep, OID_AUTO, prot_fault_translation, CTLFLAG_RW,
&prot_fault_translation, 0, "Select signal to deliver on protection fault");
/*
* Exception, fault, and trap interface to the FreeBSD 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.
*/
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) {
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 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_DTRACE_PROBE || type == T_DTRACE_RET ||
type == T_BPTFLT) {
struct reg regs;
fill_frame_regs(frame, ®s);
if (type == T_DTRACE_PROBE &&
dtrace_fasttrap_probe_ptr != NULL &&
dtrace_fasttrap_probe_ptr(®s) == 0)
goto out;
if (type == T_BPTFLT &&
dtrace_pid_probe_ptr != NULL &&
dtrace_pid_probe_ptr(®s) == 0)
goto out;
if (type == T_DTRACE_RET &&
dtrace_return_probe_ptr != NULL &&
dtrace_return_probe_ptr(®s) == 0)
goto out;
}
if ((type == T_PROTFLT || type == T_PAGEFLT) &&
dtrace_trap_func != NULL && (*dtrace_trap_func)(frame, type))
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 conditionally
* reenable interrupts. If we hold a spin lock, then
* we must not reenable interrupts. This might be a
* spurious page fault.
*/
eva = rcr2();
if (td->td_md.md_spinlock_count == 0)
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;
}
static int
trap_pfault(frame, usermode, eva)
struct trapframe *frame;
int usermode;
vm_offset_t eva;
{
vm_offset_t va;
struct vmspace *vm = NULL;
vm_map_t map;
int rv = 0;
vm_prot_t ftype;
struct thread *td = curthread;
struct proc *p = td->td_proc;
if (__predict_false((td->td_pflags & TDP_NOFAULTING) != 0)) {
/*
* Due to both processor errata and lazy TLB invalidation when
* access restrictions are removed from virtual pages, memory
* accesses that are allowed by the physical mapping layer may
* nonetheless cause one spurious page fault per virtual page.
* When the thread is executing a "no faulting" section that
* is bracketed by vm_fault_{disable,enable}_pagefaults(),
* every page fault is treated as a spurious page fault,
* unless it accesses the same virtual address as the most
* recent page fault within the same "no faulting" section.
*/
if (td->td_md.md_spurflt_addr != eva ||
(td->td_pflags & TDP_RESETSPUR) != 0) {
/*
* Do nothing to the TLB. A stale TLB entry is
* flushed automatically by a page fault.
*/
td->td_md.md_spurflt_addr = eva;
td->td_pflags &= ~TDP_RESETSPUR;
return (0);
}
} else {
/*
* 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, eva);
return (-1);
}
}
va = trunc_page(eva);
if (va >= KERNBASE) {
/*
* Don't allow user-mode faults in kernel address space.
* An exception: if the faulting address is the invalid
* instruction entry in the IDT, then the Intel Pentium
* F00F bug workaround was triggered, and we need to
* treat it is as an illegal instruction, and not a page
* fault.
*/
#if defined(I586_CPU) && !defined(NO_F00F_HACK)
if ((eva == (unsigned int)&idt[6]) && has_f00f_bug)
return -2;
#endif
if (usermode)
goto nogo;
map = kernel_map;
} else {
/*
* This is a fault on non-kernel virtual memory.
* vm is initialized above to NULL. If curproc is NULL
* or curproc->p_vmspace is NULL the fault is fatal.
*/
if (p != NULL)
vm = p->p_vmspace;
if (vm == NULL)
goto nogo;
map = &vm->vm_map;
if (!usermode && (td->td_intr_nesting_level != 0 ||
PCPU_GET(curpcb)->pcb_onfault == NULL)) {
trap_fatal(frame, eva);
return (-1);
}
}
/*
* PGEX_I is defined only if the execute disable bit capability is
* supported and enabled.
*/
if (frame->tf_err & PGEX_W)
ftype = VM_PROT_WRITE;
#ifdef PAE
else if ((frame->tf_err & PGEX_I) && pg_nx != 0)
ftype = VM_PROT_EXECUTE;
#endif
else
ftype = VM_PROT_READ;
if (map != kernel_map) {
/*
* Keep swapout from messing with us during this
* critical time.
*/
PROC_LOCK(p);
++p->p_lock;
PROC_UNLOCK(p);
/* Fault in the user page: */
rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL);
PROC_LOCK(p);
--p->p_lock;
PROC_UNLOCK(p);
} else {
/*
* Don't have to worry about process locking or stacks in the
* kernel.
*/
rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL);
}
if (rv == KERN_SUCCESS) {
#ifdef HWPMC_HOOKS
if (ftype == VM_PROT_READ || ftype == VM_PROT_WRITE) {
PMC_SOFT_CALL_TF( , , page_fault, all, frame);
if (ftype == VM_PROT_READ)
PMC_SOFT_CALL_TF( , , page_fault, read,
frame);
else
PMC_SOFT_CALL_TF( , , page_fault, write,
frame);
}
#endif
return (0);
}
nogo:
if (!usermode) {
if (td->td_intr_nesting_level == 0 &&
PCPU_GET(curpcb)->pcb_onfault != NULL) {
frame->tf_eip = (int)PCPU_GET(curpcb)->pcb_onfault;
return (0);
}
trap_fatal(frame, eva);
return (-1);
}
return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV);
}
static void
trap_fatal(frame, eva)
struct trapframe *frame;
vm_offset_t eva;
{
int code, ss, esp;
u_int type;
struct soft_segment_descriptor softseg;
char *msg;
code = frame->tf_err;
type = frame->tf_trapno;
sdtossd(&gdt[IDXSEL(frame->tf_cs & 0xffff)].sd, &softseg);
if (type <= MAX_TRAP_MSG)
msg = trap_msg[type];
else
msg = "UNKNOWN";
printf("\n\nFatal trap %d: %s while in %s mode\n", type, msg,
frame->tf_eflags & PSL_VM ? "vm86" :
ISPL(frame->tf_cs) == SEL_UPL ? "user" : "kernel");
#ifdef SMP
/* two separate prints in case of a trap on an unmapped page */
printf("cpuid = %d; ", PCPU_GET(cpuid));
printf("apic id = %02x\n", PCPU_GET(apic_id));
#endif
if (type == T_PAGEFLT) {
printf("fault virtual address = 0x%x\n", eva);
printf("fault code = %s %s, %s\n",
code & PGEX_U ? "user" : "supervisor",
code & PGEX_W ? "write" : "read",
code & PGEX_P ? "protection violation" : "page not present");
}
printf("instruction pointer = 0x%x:0x%x\n",
frame->tf_cs & 0xffff, frame->tf_eip);
if ((ISPL(frame->tf_cs) == SEL_UPL) || (frame->tf_eflags & PSL_VM)) {
ss = frame->tf_ss & 0xffff;
esp = frame->tf_esp;
} else {
ss = GSEL(GDATA_SEL, SEL_KPL);
esp = (int)&frame->tf_esp;
}
printf("stack pointer = 0x%x:0x%x\n", ss, esp);
printf("frame pointer = 0x%x:0x%x\n", ss, frame->tf_ebp);
printf("code segment = base 0x%x, limit 0x%x, type 0x%x\n",
softseg.ssd_base, softseg.ssd_limit, softseg.ssd_type);
printf(" = DPL %d, pres %d, def32 %d, gran %d\n",
softseg.ssd_dpl, softseg.ssd_p, softseg.ssd_def32,
softseg.ssd_gran);
printf("processor eflags = ");
if (frame->tf_eflags & PSL_T)
printf("trace trap, ");
if (frame->tf_eflags & PSL_I)
printf("interrupt enabled, ");
if (frame->tf_eflags & PSL_NT)
printf("nested task, ");
if (frame->tf_eflags & PSL_RF)
printf("resume, ");
if (frame->tf_eflags & PSL_VM)
printf("vm86, ");
printf("IOPL = %d\n", (frame->tf_eflags & PSL_IOPL) >> 12);
printf("current process = ");
if (curproc) {
printf("%lu (%s)\n", (u_long)curproc->p_pid, curthread->td_name);
} else {
printf("Idle\n");
}
#ifdef KDB
if (debugger_on_panic || kdb_active) {
frame->tf_err = eva; /* smuggle fault address to ddb */
if (kdb_trap(type, 0, frame)) {
frame->tf_err = code; /* restore error code */
return;
}
frame->tf_err = code; /* restore error code */
}
#endif
printf("trap number = %d\n", type);
if (type <= MAX_TRAP_MSG)
panic("%s", trap_msg[type]);
else
panic("unknown/reserved trap");
}
/*
* Double fault handler. Called when a fault occurs while writing
* a frame for a trap/exception onto the stack. This usually occurs
* when the stack overflows (such is the case with infinite recursion,
* for example).
*
* XXX Note that the current PTD gets replaced by IdlePTD when the
* task switch occurs. This means that the stack that was active at
* the time of the double fault is not available at <kstack> unless
* the machine was idle when the double fault occurred. The downside
* of this is that "trace <ebp>" in ddb won't work.
*/
void
dblfault_handler()
{
#ifdef KDTRACE_HOOKS
if (dtrace_doubletrap_func != NULL)
(*dtrace_doubletrap_func)();
#endif
printf("\nFatal double fault:\n");
printf("eip = 0x%x\n", PCPU_GET(common_tss.tss_eip));
printf("esp = 0x%x\n", PCPU_GET(common_tss.tss_esp));
printf("ebp = 0x%x\n", PCPU_GET(common_tss.tss_ebp));
#ifdef SMP
/* two separate prints in case of a trap on an unmapped page */
printf("cpuid = %d; ", PCPU_GET(cpuid));
printf("apic id = %02x\n", PCPU_GET(apic_id));
#endif
panic("double fault");
}
int
cpu_fetch_syscall_args(struct thread *td, struct syscall_args *sa)
{
struct proc *p;
struct trapframe *frame;
caddr_t params;
int error;
p = td->td_proc;
frame = td->td_frame;
params = (caddr_t)frame->tf_esp + sizeof(int);
sa->code = frame->tf_eax;
/*
* Need to check if this is a 32 bit or 64 bit syscall.
*/
if (sa->code == SYS_syscall) {
/*
* Code is first argument, followed by actual args.
*/
sa->code = fuword(params);
params += sizeof(int);
} else if (sa->code == SYS___syscall) {
/*
* Like syscall, but code is a quad, so as to maintain
* quad alignment for the rest of the arguments.
*/
sa->code = fuword(params);
params += sizeof(quad_t);
}
if (p->p_sysent->sv_mask)
sa->code &= p->p_sysent->sv_mask;
if (sa->code >= p->p_sysent->sv_size)
sa->callp = &p->p_sysent->sv_table[0];
else
sa->callp = &p->p_sysent->sv_table[sa->code];
sa->narg = sa->callp->sy_narg;
if (params != NULL && sa->narg != 0)
error = copyin(params, (caddr_t)sa->args,
(u_int)(sa->narg * sizeof(int)));
else
error = 0;
if (error == 0) {
td->td_retval[0] = 0;
td->td_retval[1] = frame->tf_edx;
}
return (error);
}
#include "../../kern/subr_syscall.c"
/*
* syscall - system call request C handler. A system call is
* essentially treated as a trap by reusing the frame layout.
*/
void
syscall(struct trapframe *frame)
{
struct thread *td;
struct syscall_args sa;
register_t orig_tf_eflags;
int error;
ksiginfo_t ksi;
#ifdef DIAGNOSTIC
if (ISPL(frame->tf_cs) != SEL_UPL) {
panic("syscall");
/* NOT REACHED */
}
#endif
orig_tf_eflags = frame->tf_eflags;
td = curthread;
td->td_frame = frame;
error = syscallenter(td, &sa);
/*
* Traced syscall.
*/
if ((orig_tf_eflags & PSL_T) && !(orig_tf_eflags & PSL_VM)) {
frame->tf_eflags &= ~PSL_T;
ksiginfo_init_trap(&ksi);
ksi.ksi_signo = SIGTRAP;
ksi.ksi_code = TRAP_TRACE;
ksi.ksi_addr = (void *)frame->tf_eip;
trapsignal(td, &ksi);
}
KASSERT(PCB_USER_FPU(td->td_pcb),
("System call %s returning with kernel FPU ctx leaked",
syscallname(td->td_proc, sa.code)));
KASSERT(td->td_pcb->pcb_save == &td->td_pcb->pcb_user_save,
("System call %s returning with mangled pcb_save",
syscallname(td->td_proc, sa.code)));
syscallret(td, error, &sa);
}