1 files changed, 43 insertions, 5 deletions

diff --git a/arch/ia64/kernel/kprobes.c b/arch/ia64/kernel/kprobes.c
index 45b8479c9864..789881ca83d4 100644
--- a/arch/ia64/kernel/kprobes.c
+++ b/arch/ia64/kernel/kprobes.c
@@ -34,6 +34,7 @@
 #include <asm/pgtable.h>
 #include <asm/kdebug.h>
 #include <asm/sections.h>
+#include <asm/uaccess.h>
 
 extern void jprobe_inst_return(void);
 
@@ -722,13 +723,50 @@ static int __kprobes kprobes_fault_handler(struct pt_regs *regs, int trapnr)
         struct kprobe *cur = kprobe_running();
         struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
 
-        if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr))
-                return 1;
 
-        if (kcb->kprobe_status & KPROBE_HIT_SS) {
-                resume_execution(cur, regs);
-                reset_current_kprobe();
+        switch(kcb->kprobe_status) {
+        case KPROBE_HIT_SS:
+        case KPROBE_REENTER:
+                /*
+                 * We are here because the instruction being single
+                 * stepped caused a page fault. We reset the current
+                 * kprobe and the instruction pointer points back to
+                 * the probe address and allow the page fault handler
+                 * to continue as a normal page fault.
+                 */
+                regs->cr_iip = ((unsigned long)cur->addr) & ~0xFULL;
+                ia64_psr(regs)->ri = ((unsigned long)cur->addr) & 0xf;
+                if (kcb->kprobe_status == KPROBE_REENTER)
+                        restore_previous_kprobe(kcb);
+                else
+                        reset_current_kprobe();
                 preempt_enable_no_resched();
+                break;
+        case KPROBE_HIT_ACTIVE:
+        case KPROBE_HIT_SSDONE:
+                /*
+                 * We increment the nmissed count for accounting,
+                 * we can also use npre/npostfault count for accouting
+                 * these specific fault cases.
+                 */
+                kprobes_inc_nmissed_count(cur);
+
+                /*
+                 * We come here because instructions in the pre/post
+                 * handler caused the page_fault, this could happen
+                 * if handler tries to access user space by
+                 * copy_from_user(), get_user() etc. Let the
+                 * user-specified handler try to fix it first.
+                 */
+                if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr))
+                        return 1;
+
+                /*
+                 * Let ia64_do_page_fault() fix it.
+                 */
+                break;
+        default:
+                break;
         }
 
         return 0;