ARM kprobes: add the kprobes hook to the page fault handler

Signed-off-by: Nicolas Pitre <nico@marvell.com>

arch/arm/mm/fault.c

@@ -12,6 +12,7 @@
 #include <linux/signal.h>
 #include <linux/mm.h>
 #include <linux/init.h>
+#include <linux/kprobes.h>
 
 #include <asm/system.h>
 #include <asm/pgtable.h>
@@ -20,6 +21,29 @@
 
 #include "fault.h"
 
+
+#ifdef CONFIG_KPROBES
+static inline int notify_page_fault(struct pt_regs *regs, unsigned int fsr)
+{
+	int ret = 0;
+
+	if (!user_mode(regs)) {
+		/* kprobe_running() needs smp_processor_id() */
+		preempt_disable();
+		if (kprobe_running() && kprobe_fault_handler(regs, fsr))
+			ret = 1;
+		preempt_enable();
+	}
+
+	return ret;
+}
+#else
+static inline int notify_page_fault(struct pt_regs *regs, unsigned int fsr)
+{
+	return 0;
+}
+#endif
+
 /*
  * This is useful to dump out the page tables associated with
  * 'addr' in mm 'mm'.
@@ -222,6 +246,9 @@ do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
 	struct mm_struct *mm;
 	int fault, sig, code;
 
+	if (notify_page_fault(regs, fsr))
+		return 0;
+
 	tsk = current;
 	mm  = tsk->mm;