Merge ../linus

[linux-drm-fsl-dcu.git] / arch / ia64 / mm / fault.c

diff --git a/arch/ia64/mm/fault.c b/arch/ia64/mm/fault.c
index af7eb087dca7af7df598e8c81c475e9b365f042c..59f3ab937615fb0fbe40ae08061b3aa47a32a775 100644 (file)
--- a/arch/ia64/mm/fault.c
+++ b/arch/ia64/mm/fault.c
@@ -19,6 +19,40 @@
 
 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)
+{
+       return atomic_notifier_chain_register(&notify_page_fault_chain, nb);
+}
+
+int unregister_page_fault_notifier(struct notifier_block *nb)
+{
+       return atomic_notifier_chain_unregister(&notify_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(&notify_page_fault_chain, val, &args);
+}
+#else
+static inline int notify_page_fault(enum die_val val, const char *str,
+                       struct pt_regs *regs, long err, int trap, int sig)
+{
+       return NOTIFY_DONE;
+}
+#endif
+
 /*
  * Return TRUE if ADDRESS points at a page in the kernel's mapped segment
  * (inside region 5, on ia64) and that page is present.
@@ -60,6 +94,9 @@ ia64_do_page_fault (unsigned long address, unsigned long isr, struct pt_regs *re
        struct siginfo si;
        unsigned long mask;
 
+       /* mmap_sem is performance critical.... */
+       prefetchw(&mm->mmap_sem);
+
        /*
         * If we're in an interrupt or have no user context, we must not take the fault..
         */
@@ -81,7 +118,7 @@ ia64_do_page_fault (unsigned long address, unsigned long isr, struct pt_regs *re
        /*
         * This is to handle the kprobes on user space access instructions
         */
-       if (notify_die(DIE_PAGE_FAULT, "page fault", regs, code, TRAP_BRKPT,
+       if (notify_page_fault(DIE_PAGE_FAULT, "page fault", regs, code, TRAP_BRKPT,
                                        SIGSEGV) == NOTIFY_STOP)
                return;
 
@@ -109,9 +146,11 @@ ia64_do_page_fault (unsigned long address, unsigned long isr, struct pt_regs *re
 #              error File is out of sync with <linux/mm.h>.  Please update.
 #      endif
 
+       if (((isr >> IA64_ISR_R_BIT) & 1UL) && (!(vma->vm_flags & (VM_READ | VM_WRITE))))
+               goto bad_area;
+
        mask = (  (((isr >> IA64_ISR_X_BIT) & 1UL) << VM_EXEC_BIT)
-               | (((isr >> IA64_ISR_W_BIT) & 1UL) << VM_WRITE_BIT)
-               | (((isr >> IA64_ISR_R_BIT) & 1UL) << VM_READ_BIT));
+               | (((isr >> IA64_ISR_W_BIT) & 1UL) << VM_WRITE_BIT));
 
        if ((vma->vm_flags & mask) != mask)
                goto bad_area;
@@ -241,7 +280,7 @@ ia64_do_page_fault (unsigned long address, unsigned long isr, struct pt_regs *re
 
   out_of_memory:
        up_read(&mm->mmap_sem);
-       if (current->pid == 1) {
+       if (is_init(current)) {
                yield();
                down_read(&mm->mmap_sem);
                goto survive;