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freebsd-dev/sys/kern/subr_trap.c
Bruce Evans 1c1771cb5b Convert npx interrupts into traps instead of vice versa. This is much 
simpler for npx exceptions that start as traps (no assembly required...)
and works better for npx exceptions that start as interrupts (there is
no longer a problem for nested interrupts).

Submitted by:	original (pre-SMPng) version by luoqi
2001-05-22 21:20:49 +00:00

1329 lines
32 KiB
C
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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
* $FreeBSD$
*/
/*
* 386 Trap and System call handling
*/
#include "opt_clock.h"
#include "opt_cpu.h"
#include "opt_ddb.h"
#include "opt_isa.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/kernel.h>
#include <sys/ktr.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
#include <vm/vm.h>
#include <vm/vm_param.h>
#include <sys/lock.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/md_var.h>
#include <machine/pcb.h>
#ifdef SMP
#include <machine/smp.h>
#endif
#include <machine/tss.h>
#include <i386/isa/icu.h>
#include <i386/isa/intr_machdep.h>
#ifdef POWERFAIL_NMI
#include <sys/syslog.h>
#include <machine/clock.h>
#endif
#include <machine/vm86.h>
#include <ddb/ddb.h>
#include <sys/sysctl.h>
int (*pmath_emulate) __P((struct trapframe *));
extern void trap __P((struct trapframe frame));
extern int trapwrite __P((unsigned addr));
extern void syscall __P((struct trapframe frame));
extern void ast __P((struct trapframe *framep));
static int trap_pfault __P((struct trapframe *, int, vm_offset_t));
static void trap_fatal __P((struct trapframe *, vm_offset_t));
void dblfault_handler __P((void));
extern inthand_t IDTVEC(lcall_syscall);
#define MAX_TRAP_MSG 28
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 */
};
#if defined(I586_CPU) && !defined(NO_F00F_HACK)
extern int has_f00f_bug;
#endif
#ifdef DDB
static int ddb_on_nmi = 1;
SYSCTL_INT(_machdep, OID_AUTO, ddb_on_nmi, CTLFLAG_RW,
&ddb_on_nmi, 0, "Go to DDB 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");
#ifdef WITNESS
extern char *syscallnames[];
#endif
void
userret(p, frame, oticks)
struct proc *p;
struct trapframe *frame;
u_quad_t oticks;
{
int sig;
while ((sig = CURSIG(p)) != 0)
postsig(sig);
mtx_lock_spin(&sched_lock);
p->p_pri.pri_level = p->p_pri.pri_user;
if (resched_wanted(p)) {
/*
* Since we are curproc, clock will normally just change
* our priority without moving us from one queue to another
* (since the running process is not on a queue.)
* If that happened after we setrunqueue ourselves but before we
* mi_switch()'ed, we might not be on the queue indicated by
* our priority.
*/
DROP_GIANT_NOSWITCH();
setrunqueue(p);
p->p_stats->p_ru.ru_nivcsw++;
mi_switch();
mtx_unlock_spin(&sched_lock);
PICKUP_GIANT();
while ((sig = CURSIG(p)) != 0)
postsig(sig);
mtx_lock_spin(&sched_lock);
}
/*
* Charge system time if profiling.
*/
if (p->p_sflag & PS_PROFIL) {
mtx_unlock_spin(&sched_lock);
/* XXX - do we need Giant? */
if (!mtx_owned(&Giant))
mtx_lock(&Giant);
addupc_task(p, TRAPF_PC(frame),
(u_int)(p->p_sticks - oticks) * psratio);
} else
mtx_unlock_spin(&sched_lock);
}
/*
* 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(frame)
struct trapframe frame;
{
struct proc *p = curproc;
u_quad_t sticks = 0;
int i = 0, ucode = 0, type, code;
vm_offset_t eva;
#ifdef POWERFAIL_NMI
static int lastalert = 0;
#endif
atomic_add_int(&cnt.v_trap, 1);
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. XXX This is really bad if we trap
* while holding a spin lock.
*/
type = frame.tf_trapno;
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, 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.
*/
printf("kernel trap %d with interrupts disabled\n",
type);
/*
* We should walk p_heldmtx here and see if any are
* spin mutexes, and not do this if so.
*/
enable_intr();
}
}
eva = 0;
#if defined(I586_CPU) && !defined(NO_F00F_HACK)
restart:
#endif
type = frame.tf_trapno;
code = frame.tf_err;
if ((ISPL(frame.tf_cs) == SEL_UPL) ||
((frame.tf_eflags & PSL_VM) && !in_vm86call)) {
/* user trap */
mtx_lock_spin(&sched_lock);
sticks = p->p_sticks;
mtx_unlock_spin(&sched_lock);
p->p_md.md_regs = &frame;
switch (type) {
case T_PRIVINFLT: /* privileged instruction fault */
ucode = type;
i = SIGILL;
break;
case T_BPTFLT: /* bpt instruction fault */
case T_TRCTRAP: /* trace trap */
frame.tf_eflags &= ~PSL_T;
i = SIGTRAP;
break;
case T_ARITHTRAP: /* arithmetic trap */
#ifdef DEV_NPX
ucode = npxtrap();
if (ucode == -1)
return;
#else
ucode = code;
#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) {
mtx_lock(&Giant);
i = vm86_emulate((struct vm86frame *)&frame);
mtx_unlock(&Giant);
if (i == 0)
goto user;
break;
}
/* FALL THROUGH */
case T_SEGNPFLT: /* segment not present fault */
case T_TSSFLT: /* invalid TSS fault */
case T_DOUBLEFLT: /* double fault */
default:
ucode = code + BUS_SEGM_FAULT ;
i = SIGBUS;
break;
case T_PAGEFLT: /* page fault */
/*
* 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.
*/
eva = rcr2();
enable_intr();
i = trap_pfault(&frame, TRUE, eva);
#if defined(I586_CPU) && !defined(NO_F00F_HACK)
if (i == -2) {
/*
* f00f hack workaround has triggered, treat
* as illegal instruction not page fault.
*/
frame.tf_trapno = T_PRIVINFLT;
goto restart;
}
#endif
if (i == -1)
goto out;
if (i == 0)
goto user;
ucode = T_PAGEFLT;
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
mtx_lock(&Giant);
if (time_second - lastalert > 10) {
log(LOG_WARNING, "NMI: power fail\n");
sysbeep(TIMER_FREQ/880, hz);
lastalert = time_second;
}
mtx_unlock(&Giant);
goto out;
#else /* !POWERFAIL_NMI */
/* machine/parity/power fail/"kitchen sink" faults */
/* XXX Giant */
if (isa_nmi(code) == 0) {
#ifdef DDB
/*
* NMI can be hooked up to a pushbutton
* for debugging.
*/
if (ddb_on_nmi) {
printf ("NMI ... going to debugger\n");
kdb_trap (type, 0, &frame);
}
#endif /* DDB */
goto out;
} 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 out;
#endif
if (!pmath_emulate) {
i = SIGFPE;
ucode = FPE_FPU_NP_TRAP;
break;
}
mtx_lock(&Giant);
i = (*pmath_emulate)(&frame);
mtx_unlock(&Giant);
if (i == 0) {
if (!(frame.tf_eflags & PSL_T))
goto out;
frame.tf_eflags &= ~PSL_T;
i = SIGTRAP;
}
/* else ucode = emulator_only_knows() XXX */
break;
case T_FPOPFLT: /* FPU operand fetch fault */
ucode = T_FPOPFLT;
i = SIGILL;
break;
}
} else {
/* kernel trap */
switch (type) {
case T_PAGEFLT: /* page fault */
/*
* 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.
*/
eva = rcr2();
enable_intr();
(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) {
mtx_lock(&Giant);
i = vm86_emulate((struct vm86frame *)&frame);
mtx_unlock(&Giant);
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 (in_vm86call)
break;
if (p->p_intr_nesting_level != 0)
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;
PROC_LOCK(p);
psignal(p, SIGBUS);
PROC_UNLOCK(p);
goto out;
}
/*
* 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) != NULL &&
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.
*/
/* XXX Giant */
if (user_dbreg_trap() && !in_vm86call) {
/*
* Reset breakpoint bits because the
* processor doesn't
*/
load_dr6(rdr6() & 0xfffffff0);
goto out;
}
/*
* Fall through (TRCTRAP kernel mode, kernel address)
*/
case T_BPTFLT:
/*
* If DDB is enabled, let it handle the debugger trap.
* Otherwise, debugger traps "can't happen".
*/
#ifdef DDB
/* XXX Giant */
if (kdb_trap (type, 0, &frame))
goto out;
#endif
break;
#ifdef DEV_ISA
case T_NMI:
#ifdef POWERFAIL_NMI
mtx_lock(&Giant);
if (time_second - lastalert > 10) {
log(LOG_WARNING, "NMI: power fail\n");
sysbeep(TIMER_FREQ/880, hz);
lastalert = time_second;
}
mtx_unlock(&Giant);
goto out;
#else /* !POWERFAIL_NMI */
/* XXX Giant */
/* 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) {
printf ("NMI ... going to debugger\n");
kdb_trap (type, 0, &frame);
}
#endif /* DDB */
goto out;
} else if (panic_on_nmi == 0)
goto out;
/* FALL THROUGH */
#endif /* POWERFAIL_NMI */
#endif /* DEV_ISA */
}
mtx_lock(&Giant);
trap_fatal(&frame, eva);
mtx_unlock(&Giant);
goto out;
}
mtx_lock(&Giant);
/* Translate fault for emulators (e.g. Linux) */
if (*p->p_sysent->sv_transtrap)
i = (*p->p_sysent->sv_transtrap)(i, type);
trapsignal(p, 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
mtx_unlock(&Giant);
user:
userret(p, &frame, sticks);
if (mtx_owned(&Giant))
mtx_unlock(&Giant);
out:
return;
}
#ifdef notyet
/*
* This version doesn't allow a page fault to user space while
* in the kernel. The rest of the kernel needs to be made "safe"
* before this can be used. I think the only things remaining
* to be made safe are the iBCS2 code and the process tracing/
* debugging code.
*/
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 = 0;
int rv = 0;
vm_prot_t ftype;
struct proc *p = curproc;
if (frame->tf_err & PGEX_W)
ftype = VM_PROT_WRITE;
else
ftype = VM_PROT_READ;
va = trunc_page(eva);
if (va < VM_MIN_KERNEL_ADDRESS) {
vm_offset_t v;
vm_page_t mpte;
if (p == NULL ||
(!usermode && va < VM_MAXUSER_ADDRESS &&
(p->p_intr_nesting_level != 0 ||
PCPU_GET(curpcb) == NULL ||
PCPU_GET(curpcb)->pcb_onfault == NULL))) {
trap_fatal(frame, eva);
return (-1);
}
/*
* 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.
*/
vm = p->p_vmspace;
if (vm == NULL)
goto nogo;
map = &vm->vm_map;
/*
* Keep swapout from messing with us during this
* critical time.
*/
PROC_LOCK(p);
++p->p_lock;
PROC_UNLOCK(p);
/*
* Grow the stack if necessary
*/
/* grow_stack returns false only if va falls into
* a growable stack region and the stack growth
* fails. It returns true if va was not within
* a growable stack region, or if the stack
* growth succeeded.
*/
if (!grow_stack (p, va))
rv = KERN_FAILURE;
else
/* 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 allow user-mode faults in kernel address space.
*/
if (usermode)
goto nogo;
/*
* Since we know that kernel virtual address addresses
* always have pte pages mapped, we just have to fault
* the page.
*/
rv = vm_fault(kernel_map, va, ftype, VM_FAULT_NORMAL);
}
if (rv == KERN_SUCCESS)
return (0);
nogo:
if (!usermode) {
if (p->p_intr_nesting_level == 0 &&
PCPU_GET(curpcb) != NULL &&
PCPU_GET(curpcb)->pcb_onfault != NULL) {
frame->tf_eip = (int)PCPU_GET(curpcb)->pcb_onfault;
return (0);
}
trap_fatal(frame, eva);
return (-1);
}
/* kludge to pass faulting virtual address to sendsig */
frame->tf_err = eva;
return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV);
}
#endif
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 = 0;
int rv = 0;
vm_prot_t ftype;
struct proc *p = curproc;
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 (frame->tf_err & PGEX_W)
ftype = VM_PROT_WRITE;
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);
/*
* Grow the stack if necessary
*/
/* grow_stack returns false only if va falls into
* a growable stack region and the stack growth
* fails. It returns true if va was not within
* a growable stack region, or if the stack
* growth succeeded.
*/
if (!grow_stack (p, va))
rv = KERN_FAILURE;
else
/* 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 (p->p_intr_nesting_level == 0 &&
PCPU_GET(curpcb) != NULL &&
PCPU_GET(curpcb)->pcb_onfault != NULL) {
frame->tf_eip = (int)PCPU_GET(curpcb)->pcb_onfault;
return (0);
}
mtx_lock(&Giant);
trap_fatal(frame, eva);
mtx_unlock(&Giant);
return (-1);
}
/* kludge to pass faulting virtual address to sendsig */
frame->tf_err = eva;
return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV);
}
static void
trap_fatal(frame, eva)
struct trapframe *frame;
vm_offset_t eva;
{
int code, type, ss, esp;
struct soft_segment_descriptor softseg;
code = frame->tf_err;
type = frame->tf_trapno;
sdtossd(&gdt[IDXSEL(frame->tf_cs & 0xffff)].sd, &softseg);
if (type <= MAX_TRAP_MSG)
printf("\n\nFatal trap %d: %s while in %s mode\n",
type, trap_msg[type],
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("lapic.id = %08x\n", lapic.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, curproc->p_comm ?
curproc->p_comm : "");
} else {
printf("Idle\n");
}
#ifdef KDB
if (kdb_trap(&psl))
return;
#endif
#ifdef DDB
if ((debugger_on_panic || db_active) && kdb_trap(type, 0, frame))
return;
#endif
printf("trap number = %d\n", type);
if (type <= MAX_TRAP_MSG)
panic(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()
{
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("lapic.id = %08x\n", lapic.id);
#endif
panic("double fault");
}
/*
* Compensate for 386 brain damage (missing URKR).
* This is a little simpler than the pagefault handler in trap() because
* it the page tables have already been faulted in and high addresses
* are thrown out early for other reasons.
*/
int trapwrite(addr)
unsigned addr;
{
struct proc *p;
vm_offset_t va;
struct vmspace *vm;
int rv;
va = trunc_page((vm_offset_t)addr);
/*
* XXX - MAX is END. Changed > to >= for temp. fix.
*/
if (va >= VM_MAXUSER_ADDRESS)
return (1);
p = curproc;
vm = p->p_vmspace;
PROC_LOCK(p);
++p->p_lock;
PROC_UNLOCK(p);
if (!grow_stack (p, va))
rv = KERN_FAILURE;
else
/*
* fault the data page
*/
rv = vm_fault(&vm->vm_map, va, VM_PROT_WRITE, VM_FAULT_DIRTY);
PROC_LOCK(p);
--p->p_lock;
PROC_UNLOCK(p);
if (rv != KERN_SUCCESS)
return 1;
return (0);
}
/*
* syscall - MP aware system call request C handler
*
* A system call is essentially treated as a trap except that the
* MP lock is not held on entry or return. We are responsible for
* obtaining the MP lock if necessary and for handling ASTs
* (e.g. a task switch) prior to return.
*
* In general, only simple access and manipulation of curproc and
* the current stack is allowed without having to hold MP lock.
*/
void
syscall(frame)
struct trapframe frame;
{
caddr_t params;
int i;
struct sysent *callp;
struct proc *p = curproc;
u_quad_t sticks;
int error;
int narg;
int args[8];
u_int code;
atomic_add_int(&cnt.v_syscall, 1);
#ifdef DIAGNOSTIC
if (ISPL(frame.tf_cs) != SEL_UPL) {
mtx_lock(&Giant);
panic("syscall");
/* NOT REACHED */
}
#endif
mtx_lock_spin(&sched_lock);
sticks = p->p_sticks;
mtx_unlock_spin(&sched_lock);
p->p_md.md_regs = &frame;
params = (caddr_t)frame.tf_esp + sizeof(int);
code = frame.tf_eax;
if (p->p_sysent->sv_prepsyscall) {
/*
* The prep code is not MP aware.
*/
mtx_lock(&Giant);
(*p->p_sysent->sv_prepsyscall)(&frame, args, &code, &params);
mtx_unlock(&Giant);
} else {
/*
* Need to check if this is a 32 bit or 64 bit syscall.
* fuword is MP aware.
*/
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 & SYF_ARGMASK;
/*
* copyin is MP aware, but the tracing code is not
*/
if (params && (i = narg * sizeof(int)) &&
(error = copyin(params, (caddr_t)args, (u_int)i))) {
mtx_lock(&Giant);
#ifdef KTRACE
if (KTRPOINT(p, KTR_SYSCALL))
ktrsyscall(p->p_tracep, code, narg, args);
#endif
goto bad;
}
/*
* Try to run the syscall without the MP lock if the syscall
* is MP safe.
*/
if ((callp->sy_narg & SYF_MPSAFE) == 0) {
mtx_lock(&Giant);
}
#ifdef KTRACE
/*
* We have to obtain the MP lock no matter what if
* we are ktracing
*/
if (KTRPOINT(p, KTR_SYSCALL)) {
if (!mtx_owned(&Giant))
mtx_lock(&Giant);
ktrsyscall(p->p_tracep, code, narg, args);
}
#endif
p->p_retval[0] = 0;
p->p_retval[1] = frame.tf_edx;
STOPEVENT(p, S_SCE, narg); /* MP aware */
error = (*callp->sy_call)(p, args);
/*
* MP SAFE (we may or may not have the MP lock at this point)
*/
switch (error) {
case 0:
frame.tf_eax = p->p_retval[0];
frame.tf_edx = p->p_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:
bad:
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. trapsignal() is not MP aware.
*/
if ((frame.tf_eflags & PSL_T) && !(frame.tf_eflags & PSL_VM)) {
if (!mtx_owned(&Giant))
mtx_lock(&Giant);
frame.tf_eflags &= ~PSL_T;
trapsignal(p, SIGTRAP, 0);
}
/*
* Handle reschedule and other end-of-syscall issues
*/
userret(p, &frame, sticks);
#ifdef KTRACE
if (KTRPOINT(p, KTR_SYSRET)) {
if (!mtx_owned(&Giant))
mtx_lock(&Giant);
ktrsysret(p->p_tracep, code, error, p->p_retval[0]);
}
#endif
/*
* Release Giant if we had to get it
*/
if (mtx_owned(&Giant))
mtx_unlock(&Giant);
/*
* 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);
#ifdef WITNESS
if (witness_list(p)) {
panic("system call %s returning with mutex(s) held\n",
syscallnames[code]);
}
#endif
mtx_assert(&sched_lock, MA_NOTOWNED);
mtx_assert(&Giant, MA_NOTOWNED);
}
void
ast(framep)
struct trapframe *framep;
{
struct proc *p = CURPROC;
u_quad_t sticks;
#if defined(DEV_NPX) && !defined(SMP)
int ucode;
#endif
KASSERT(TRAPF_USERMODE(framep), ("ast in kernel mode"));
/*
* We check for a pending AST here rather than in the assembly as
* acquiring and releasing mutexes in assembly is not fun.
*/
mtx_lock_spin(&sched_lock);
if (!(astpending(p) || resched_wanted(p))) {
mtx_unlock_spin(&sched_lock);
return;
}
sticks = p->p_sticks;
p->p_md.md_regs = framep;
astoff(p);
cnt.v_soft++;
mtx_intr_enable(&sched_lock);
if (p->p_sflag & PS_OWEUPC) {
p->p_sflag &= ~PS_OWEUPC;
mtx_unlock_spin(&sched_lock);
mtx_lock(&Giant);
mtx_lock_spin(&sched_lock);
addupc_task(p, p->p_stats->p_prof.pr_addr,
p->p_stats->p_prof.pr_ticks);
}
if (p->p_sflag & PS_ALRMPEND) {
p->p_sflag &= ~PS_ALRMPEND;
mtx_unlock_spin(&sched_lock);
PROC_LOCK(p);
psignal(p, SIGVTALRM);
PROC_UNLOCK(p);
mtx_lock_spin(&sched_lock);
}
#if defined(DEV_NPX) && !defined(SMP)
if (PCPU_GET(curpcb)->pcb_flags & PCB_NPXTRAP) {
PCPU_GET(curpcb)->pcb_flags &= ~PCB_NPXTRAP;
mtx_unlock_spin(&sched_lock);
ucode = npxtrap();
if (ucode != -1) {
if (!mtx_owned(&Giant))
mtx_lock(&Giant);
trapsignal(p, SIGFPE, ucode);
}
mtx_lock_spin(&sched_lock);
}
#endif
if (p->p_sflag & PS_PROFPEND) {
p->p_sflag &= ~PS_PROFPEND;
mtx_unlock_spin(&sched_lock);
PROC_LOCK(p);
psignal(p, SIGPROF);
PROC_UNLOCK(p);
} else
mtx_unlock_spin(&sched_lock);
userret(p, framep, sticks);
if (mtx_owned(&Giant))
mtx_unlock(&Giant);
}
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