sh: kprobes: Hook up kprobe_fault_handler() in the page fault path.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

arch/sh/include/asm/kprobes.h

@@ -6,8 +6,6 @@
 #include <linux/types.h>
 #include <linux/ptrace.h>
 
-struct pt_regs;
-
 typedef u16 kprobe_opcode_t;
 #define BREAKPOINT_INSTRUCTION	0xc3ff
 
@@ -48,6 +46,7 @@ struct kprobe_ctlblk {
 	struct prev_kprobe prev_kprobe;
 };
 
+extern int kprobe_fault_handler(struct pt_regs *regs, int trapnr);
 extern int kprobe_exceptions_notify(struct notifier_block *self,
 				    unsigned long val, void *data);
 extern int kprobe_handle_illslot(unsigned long pc);

arch/sh/kernel/kprobes.c

@@ -393,7 +393,7 @@ static inline int post_kprobe_handler(struct pt_regs *regs)
 	return 1;
 }
 
-static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
+int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
 {
 	struct kprobe *cur = kprobe_running();
 	struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();

arch/sh/mm/fault_32.c

@@ -2,7 +2,7 @@
  * Page fault handler for SH with an MMU.
  *
  *  Copyright (C) 1999  Niibe Yutaka
- *  Copyright (C) 2003 - 2007  Paul Mundt
+ *  Copyright (C) 2003 - 2008  Paul Mundt
  *
  *  Based on linux/arch/i386/mm/fault.c:
  *   Copyright (C) 1995  Linus Torvalds
@@ -21,6 +21,27 @@
 #include <asm/tlbflush.h>
 #include <asm/kgdb.h>
 
+#ifdef CONFIG_KPROBES
+static inline int notify_page_fault(struct pt_regs *regs, int trap)
+{
+	int ret = 0;
+
+	if (!user_mode(regs)) {
+		preempt_disable();
+		if (kprobe_running() && kprobe_fault_handler(regs, trap))
+			ret = 1;
+		preempt_enable();
+	}
+
+	return ret;
+}
+#else
+static inline int notify_page_fault(struct pt_regs *regs, int trap)
+{
+	return 0;
+}
+#endif
+
 /*
  * This routine handles page faults.  It determines the address,
  * and the problem, and then passes it off to one of the appropriate
@@ -37,6 +58,9 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
 	int fault;
 	siginfo_t info;
 
+	if (notify_page_fault(regs, writeaccess))
+		return;
+
 #ifdef CONFIG_SH_KGDB
 	if (kgdb_nofault && kgdb_bus_err_hook)
 		kgdb_bus_err_hook();
@@ -269,6 +293,9 @@ asmlinkage int __kprobes __do_page_fault(struct pt_regs *regs,
 	pte_t *pte;
 	pte_t entry;
 
+	if (notify_page_fault(regs, writeaccess))
+		return 0;
+
 #ifdef CONFIG_SH_KGDB
 	if (kgdb_nofault && kgdb_bus_err_hook)
 		kgdb_bus_err_hook();