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/*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 1995 - 2000 by Ralf Baechle
* Copyright (C) 1999, 2000 by Silicon Graphics, Inc.
*/
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/ptrace.h>
#include <linux/mman.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/smp_lock.h>
#include <linux/version.h>
#include <asm/hardirq.h>
#include <asm/pgalloc.h>
#include <asm/mmu_context.h>
#include <asm/softirq.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/ptrace.h>
#define development_version (LINUX_VERSION_CODE & 0x100)
extern void die(char *, struct pt_regs *, unsigned long write);
/*
* Macro for exception fixup code to access integer registers.
*/
#define dpf_reg(r) (regs->regs[r])
asmlinkage void
dodebug(abi64_no_regargs, struct pt_regs regs)
{
printk("Got syscall %ld, cpu %d proc %s:%d epc 0x%lx\n", regs.regs[2],
smp_processor_id(), current->comm, current->pid, regs.cp0_epc);
}
asmlinkage void
dodebug2(abi64_no_regargs, struct pt_regs regs)
{
unsigned long retaddr;
__asm__ __volatile__(
".set noreorder\n\t"
"add %0,$0,$31\n\t"
".set reorder"
: "=r" (retaddr));
printk("Got exception 0x%lx at 0x%lx\n", retaddr, regs.cp0_epc);
}
extern spinlock_t console_lock, timerlist_lock;
/*
* Unlock any spinlocks which will prevent us from getting the
* message out (timerlist_lock is aquired through the
* console unblank code)
*/
void bust_spinlocks(void)
{
spin_lock_init(&console_lock);
spin_lock_init(&timerlist_lock);
}
/*
* This routine handles page faults. It determines the address,
* and the problem, and then passes it off to one of the appropriate
* routines.
*/
asmlinkage void
do_page_fault(struct pt_regs *regs, unsigned long write, unsigned long address)
{
struct vm_area_struct * vma;
struct task_struct *tsk = current;
struct mm_struct *mm = tsk->mm;
unsigned long fixup;
siginfo_t info;
info.si_code = SEGV_MAPERR;
/*
* If we're in an interrupt or have no user
* context, we must not take the fault..
*/
if (in_interrupt() || mm == &init_mm)
goto no_context;
#if DEBUG_MIPS64
printk("Cpu%d[%s:%d:%08lx:%ld:%08lx]\n", smp_processor_id(), current->comm,
current->pid, address, write, regs->cp0_epc);
#endif
down(&mm->mmap_sem);
vma = find_vma(mm, address);
if (!vma)
goto bad_area;
if (vma->vm_start <= address)
goto good_area;
if (!(vma->vm_flags & VM_GROWSDOWN))
goto bad_area;
if (expand_stack(vma, address))
goto bad_area;
/*
* Ok, we have a good vm_area for this memory access, so
* we can handle it..
*/
good_area:
info.si_code = SEGV_ACCERR;
if (write) {
if (!(vma->vm_flags & VM_WRITE))
goto bad_area;
} else {
if (!(vma->vm_flags & (VM_READ | VM_EXEC)))
goto bad_area;
}
/*
* If for any reason at all we couldn't handle the fault,
* make sure we exit gracefully rather than endlessly redo
* the fault.
*/
switch (handle_mm_fault(mm, vma, address, write)) {
case 1:
tsk->min_flt++;
break;
case 2:
tsk->maj_flt++;
break;
case 0:
goto do_sigbus;
default:
goto out_of_memory;
}
up(&mm->mmap_sem);
return;
/*
* Something tried to access memory that isn't in our memory map..
* Fix it, but check if it's kernel or user first..
*/
bad_area:
up(&mm->mmap_sem);
/*
* Quickly check for vmalloc range faults.
*/
if ((!vma) && (address >= VMALLOC_START) && (address < VMALLOC_END)) {
printk("Fix vmalloc invalidate fault\n");
while(1);
}
if (user_mode(regs)) {
tsk->thread.cp0_badvaddr = address;
tsk->thread.error_code = write;
#if 0
printk("do_page_fault() #2: sending SIGSEGV to %s for illegal %s\n"
"%08lx (epc == %08lx, ra == %08lx)\n",
tsk->comm,
write ? "write access to" : "read access from",
address,
(unsigned long) regs->cp0_epc,
(unsigned long) regs->regs[31]);
#endif
info.si_signo = SIGSEGV;
info.si_errno = 0;
/* info.si_code has been set above */
info.si_addr = (void *) address;
force_sig_info(SIGSEGV, &info, tsk);
return;
}
no_context:
/* Are we prepared to handle this kernel fault? */
fixup = search_exception_table(regs->cp0_epc);
if (fixup) {
long new_epc;
tsk->thread.cp0_baduaddr = address;
new_epc = fixup_exception(dpf_reg, fixup, regs->cp0_epc);
if (development_version)
printk(KERN_DEBUG "%s: Exception at [<%lx>] (%lx)\n",
tsk->comm, regs->cp0_epc, new_epc);
regs->cp0_epc = new_epc;
return;
}
/*
* Oops. The kernel tried to access some bad page. We'll have to
* terminate things with extreme prejudice.
*/
bust_spinlocks();
printk(KERN_ALERT "Cpu %d Unable to handle kernel paging request at "
"address %08lx, epc == %08x, ra == %08x\n",
smp_processor_id(), address, (unsigned int) regs->cp0_epc,
(unsigned int) regs->regs[31]);
die("Oops", regs, write);
do_exit(SIGKILL);
/*
* We ran out of memory, or some other thing happened to us that made
* us unable to handle the page fault gracefully.
*/
out_of_memory:
up(&mm->mmap_sem);
printk("VM: killing process %s\n", tsk->comm);
if (user_mode(regs))
do_exit(SIGKILL);
goto no_context;
do_sigbus:
up(&mm->mmap_sem);
/*
* Send a sigbus, regardless of whether we were in kernel
* or user mode.
*/
tsk->thread.cp0_badvaddr = address;
info.si_code = SIGBUS;
info.si_errno = 0;
info.si_code = BUS_ADRERR;
info.si_addr = (void *) address;
force_sig_info(SIGBUS, &info, tsk);
/* Kernel mode? Handle exceptions or die */
if (!user_mode(regs))
goto no_context;
}
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