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freebsd-skq/sys/i386/i386/trap.c
jhb 370298a108 Implement simple machine check support for amd64 and i386. 
- For CPUs that only support MCE (the machine check exception) but not MCA
  (i.e. Pentium), all this does is print out the value of the machine check
  registers and then panic when a machine check exception occurs.
- For CPUs that support MCA (the machine check architecture), the support is
  a bit more involved.
  - First, there is limited support for decoding the CPU-independent MCA
    error codes in the kernel, and the kernel uses this to output a short
    description of any machine check events that occur.
  - When a machine check exception occurs, all of the MCx banks on the
    current CPU are scanned and any events are reported to the console
    before panic'ing.
  - To catch events for correctable errors, a periodic timer kicks off a
    task which scans the MCx banks on all CPUs.  The frequency of these
    checks is controlled via the "hw.mca.interval" sysctl.
  - Userland can request an immediate scan of the MCx banks by writing
    a non-zero value to "hw.mca.force_scan".
  - If any correctable events are encountered, the appropriate details
    are stored in a 'struct mca_record' (defined in <machine/mca.h>).
    The "hw.mca.count" is a count of such records and each record may
    be queried via the "hw.mca.records" tree by specifying the record
    index (0 .. count - 1) as the next name in the MIB similar to using
    PIDs with the kern.proc.* sysctls.  The idea is to export machine
    check events to userland for more detailed processing.
  - The periodic timer and hw.mca sysctls are only present if the CPU
    supports MCA.

Discussed with:	emaste (briefly)
MFC after:	1 month
2009-05-13 17:53:04 +00:00

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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("$FreeBSD$");
/*
* 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_ktrace.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 KTRACE
#include <sys/ktrace.h>
#endif
#ifdef HWPMC_HOOKS
#include <sys/pmckern.h>
#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 <machine/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;
#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 30
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 */
};
#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");
#endif
static int panic_on_nmi = 1;
SYSCTL_INT(_machdep, OID_AUTO, panic_on_nmi, CTLFLAG_RW,
&panic_on_nmi, 0, "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");
extern char *syscallnames[];
/*
* 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
#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 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 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;
#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))
printf(
"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 (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;
}
}
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
/* transparent fault (due to context switch "late") */
if (npxdna())
goto userout;
#endif
printf("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
/*
* The kernel is apparently using npx for copying.
* XXX this should be fatal unless the kernel has
* registered such use.
*/
if (npxdna())
goto out;
#endif
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)
/*
* 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);
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);
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;
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;
}
/*
* 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,
(ftype & VM_PROT_WRITE) ? VM_FAULT_DIRTY
: 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)
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");
}
/*
* syscall - system call request C handler
*
* A system call is essentially treated as a trap.
*/
void
syscall(struct trapframe *frame)
{
caddr_t params;
struct sysent *callp;
struct thread *td = curthread;
struct proc *p = td->td_proc;
register_t orig_tf_eflags;
int error;
int narg;
int args[8];
u_int code;
ksiginfo_t ksi;
PCPU_INC(cnt.v_syscall);
#ifdef DIAGNOSTIC
if (ISPL(frame->tf_cs) != SEL_UPL) {
panic("syscall");
/* NOT REACHED */
}
#endif
td->td_pticks = 0;
td->td_frame = frame;
if (td->td_ucred != p->p_ucred)
cred_update_thread(td);
params = (caddr_t)frame->tf_esp + sizeof(int);
code = frame->tf_eax;
orig_tf_eflags = frame->tf_eflags;
if (p->p_sysent->sv_prepsyscall) {
(*p->p_sysent->sv_prepsyscall)(frame, args, &code, &params);
} else {
/*
* Need to check if this is a 32 bit or 64 bit syscall.
*/
if (code == SYS_syscall) {
/*
* Code is first argument, followed by actual args.
*/
code = fuword(params);
params += sizeof(int);
} else if (code == SYS___syscall) {
/*
* Like syscall, but code is a quad, so as to maintain
* quad alignment for the rest of the arguments.
*/
code = fuword(params);
params += sizeof(quad_t);
}
}
if (p->p_sysent->sv_mask)
code &= p->p_sysent->sv_mask;
if (code >= p->p_sysent->sv_size)
callp = &p->p_sysent->sv_table[0];
else
callp = &p->p_sysent->sv_table[code];
narg = callp->sy_narg;
if (params != NULL && narg != 0)
error = copyin(params, (caddr_t)args,
(u_int)(narg * sizeof(int)));
else
error = 0;
#ifdef KTRACE
if (KTRPOINT(td, KTR_SYSCALL))
ktrsyscall(code, narg, args);
#endif
CTR4(KTR_SYSC, "syscall enter thread %p pid %d proc %s code %d", td,
td->td_proc->p_pid, td->td_name, code);
td->td_syscalls++;
if (error == 0) {
td->td_retval[0] = 0;
td->td_retval[1] = frame->tf_edx;
STOPEVENT(p, S_SCE, narg);
PTRACESTOP_SC(p, td, S_PT_SCE);
#ifdef KDTRACE_HOOKS
/*
* If the systrace module has registered it's probe
* callback and if there is a probe active for the
* syscall 'entry', process the probe.
*/
if (systrace_probe_func != NULL && callp->sy_entry != 0)
(*systrace_probe_func)(callp->sy_entry, code, callp,
args);
#endif
AUDIT_SYSCALL_ENTER(code, td);
error = (*callp->sy_call)(td, args);
AUDIT_SYSCALL_EXIT(error, td);
/* Save the latest error return value. */
td->td_errno = error;
#ifdef KDTRACE_HOOKS
/*
* If the systrace module has registered it's probe
* callback and if there is a probe active for the
* syscall 'return', process the probe.
*/
if (systrace_probe_func != NULL && callp->sy_return != 0)
(*systrace_probe_func)(callp->sy_return, code, callp,
args);
#endif
}
switch (error) {
case 0:
frame->tf_eax = td->td_retval[0];
frame->tf_edx = td->td_retval[1];
frame->tf_eflags &= ~PSL_C;
break;
case ERESTART:
/*
* Reconstruct pc, assuming lcall $X,y is 7 bytes,
* int 0x80 is 2 bytes. We saved this in tf_err.
*/
frame->tf_eip -= frame->tf_err;
break;
case EJUSTRETURN:
break;
default:
if (p->p_sysent->sv_errsize) {
if (error >= p->p_sysent->sv_errsize)
error = -1; /* XXX */
else
error = p->p_sysent->sv_errtbl[error];
}
frame->tf_eax = error;
frame->tf_eflags |= PSL_C;
break;
}
/*
* 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);
}
/*
* Check for misbehavior.
*/
WITNESS_WARN(WARN_PANIC, NULL, "System call %s returning",
(code >= 0 && code < SYS_MAXSYSCALL) ? syscallnames[code] : "???");
KASSERT(td->td_critnest == 0,
("System call %s returning in a critical section",
(code >= 0 && code < SYS_MAXSYSCALL) ? syscallnames[code] : "???"));
KASSERT(td->td_locks == 0,
("System call %s returning with %d locks held",
(code >= 0 && code < SYS_MAXSYSCALL) ? syscallnames[code] : "???",
td->td_locks));
/*
* Handle reschedule and other end-of-syscall issues
*/
userret(td, frame);
CTR4(KTR_SYSC, "syscall exit thread %p pid %d proc %s code %d", td,
td->td_proc->p_pid, td->td_name, code);
#ifdef KTRACE
if (KTRPOINT(td, KTR_SYSRET))
ktrsysret(code, error, td->td_retval[0]);
#endif
/*
* This works because errno is findable through the
* register set. If we ever support an emulation where this
* is not the case, this code will need to be revisited.
*/
STOPEVENT(p, S_SCX, code);
PTRACESTOP_SC(p, td, S_PT_SCX);
}
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