extern void die (char *, struct pt_regs *, long);
#ifdef CONFIG_KPROBES
-ATOMIC_NOTIFIER_HEAD(notify_page_fault_chain);
-
-/* Hook to register for page fault notifications */
-int register_page_fault_notifier(struct notifier_block *nb)
+static inline int notify_page_fault(struct pt_regs *regs, int trap)
{
- return atomic_notifier_chain_register(¬ify_page_fault_chain, nb);
-}
+ int ret = 0;
+
+ if (!user_mode(regs)) {
+ /* kprobe_running() needs smp_processor_id() */
+ preempt_disable();
+ if (kprobe_running() && kprobes_fault_handler(regs, trap))
+ ret = 1;
+ preempt_enable();
+ }
-int unregister_page_fault_notifier(struct notifier_block *nb)
-{
- return atomic_notifier_chain_unregister(¬ify_page_fault_chain, nb);
-}
-
-static inline int notify_page_fault(enum die_val val, const char *str,
- struct pt_regs *regs, long err, int trap, int sig)
-{
- struct die_args args = {
- .regs = regs,
- .str = str,
- .err = err,
- .trapnr = trap,
- .signr = sig
- };
- return atomic_notifier_call_chain(¬ify_page_fault_chain, val, &args);
+ return ret;
}
#else
-static inline int notify_page_fault(enum die_val val, const char *str,
- struct pt_regs *regs, long err, int trap, int sig)
+static inline int notify_page_fault(struct pt_regs *regs, int trap)
{
- return NOTIFY_DONE;
+ return 0;
}
#endif
struct mm_struct *mm = current->mm;
struct siginfo si;
unsigned long mask;
+ int fault;
/* mmap_sem is performance critical.... */
prefetchw(&mm->mmap_sem);
/*
* This is to handle the kprobes on user space access instructions
*/
- if (notify_page_fault(DIE_PAGE_FAULT, "page fault", regs, code, TRAP_BRKPT,
- SIGSEGV) == NOTIFY_STOP)
+ if (notify_page_fault(regs, TRAP_BRKPT))
return;
down_read(&mm->mmap_sem);
vma = find_vma_prev(mm, address, &prev_vma);
- if (!vma)
+ if (!vma && !prev_vma )
goto bad_area;
- /* find_vma_prev() returns vma such that address < vma->vm_end or NULL */
- if (address < vma->vm_start)
+ /*
+ * find_vma_prev() returns vma such that address < vma->vm_end or NULL
+ *
+ * May find no vma, but could be that the last vm area is the
+ * register backing store that needs to expand upwards, in
+ * this case vma will be null, but prev_vma will ne non-null
+ */
+ if (( !vma && prev_vma ) || (address < vma->vm_start) )
goto check_expansion;
good_area:
* sure we exit gracefully rather than endlessly redo the
* fault.
*/
- switch (handle_mm_fault(mm, vma, address, (mask & VM_WRITE) != 0)) {
- case VM_FAULT_MINOR:
- ++current->min_flt;
- break;
- case VM_FAULT_MAJOR:
- ++current->maj_flt;
- break;
- case VM_FAULT_SIGBUS:
+ fault = handle_mm_fault(mm, vma, address, (mask & VM_WRITE) != 0);
+ if (unlikely(fault & VM_FAULT_ERROR)) {
/*
* We ran out of memory, or some other thing happened
* to us that made us unable to handle the page fault
* gracefully.
*/
- signal = SIGBUS;
- goto bad_area;
- case VM_FAULT_OOM:
- goto out_of_memory;
- default:
+ if (fault & VM_FAULT_OOM) {
+ goto out_of_memory;
+ } else if (fault & VM_FAULT_SIGBUS) {
+ signal = SIGBUS;
+ goto bad_area;
+ }
BUG();
}
+ if (fault & VM_FAULT_MAJOR)
+ current->maj_flt++;
+ else
+ current->min_flt++;
up_read(&mm->mmap_sem);
return;
check_expansion:
if (!(prev_vma && (prev_vma->vm_flags & VM_GROWSUP) && (address == prev_vma->vm_end))) {
+ if (!vma)
+ goto bad_area;
if (!(vma->vm_flags & VM_GROWSDOWN))
goto bad_area;
if (REGION_NUMBER(address) != REGION_NUMBER(vma->vm_start)
}
printk(KERN_CRIT "VM: killing process %s\n", current->comm);
if (user_mode(regs))
- do_exit(SIGKILL);
+ do_group_exit(SIGKILL);
goto no_context;
}