[S390] get rid of kprobes notifier call chain.

And here's a port of the powerpc patch to get rid of the notifier
chain completely to s390.  It's ontop of Martins patch as that one
is in mainline already.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

diff --git a/arch/s390/kernel/kprobes.c b/arch/s390/kernel/kprobes.c
index 993f353..23c61f6 100644 (file)
--- a/arch/s390/kernel/kprobes.c
+++ b/arch/s390/kernel/kprobes.c
@@ -516,7 +516,7 @@ out:
        return 1;
 }
 
-static int __kprobes 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();
@@ -603,7 +603,6 @@ int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
                        ret = NOTIFY_STOP;
                break;
        case DIE_TRAP:
-       case DIE_PAGE_FAULT:
                /* kprobe_running() needs smp_processor_id() */
                preempt_disable();
                if (kprobe_running() &&

diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c
index 2b76a87..91f705a 100644 (file)
--- a/arch/s390/mm/fault.c
+++ b/arch/s390/mm/fault.c
@@ -52,38 +52,24 @@ extern int sysctl_userprocess_debug;
 extern void die(const char *,struct pt_regs *,long);
 
 #ifdef CONFIG_KPROBES
-static ATOMIC_NOTIFIER_HEAD(notify_page_fault_chain);
-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 int __kprobes __notify_page_fault(struct pt_regs *regs, long err)
-{
-       struct die_args args = { .str = "page fault",
-                                .trapnr = 14,
-                                .signr = SIGSEGV };
-       args.regs = regs;
-       args.err = err;
-       return atomic_notifier_call_chain(&notify_page_fault_chain,
-                                         DIE_PAGE_FAULT, &args);
-}
-
 static inline int notify_page_fault(struct pt_regs *regs, long err)
 {
-       if (unlikely(kprobe_running()))
-               return __notify_page_fault(regs, err);
-       return NOTIFY_DONE;
+       int ret = 0;
+
+       /* kprobe_running() needs smp_processor_id() */
+       if (!user_mode(regs)) {
+               preempt_disable();
+               if (kprobe_running() && kprobe_fault_handler(regs, 14))
+                       ret = 1;
+               preempt_enable();
+       }
+
+       return ret;
 }
 #else
 static inline int notify_page_fault(struct pt_regs *regs, long err)
 {
-       return NOTIFY_DONE;
+       return 0;
 }
 #endif
 
@@ -319,7 +305,7 @@ do_exception(struct pt_regs *regs, unsigned long error_code, int write)
        int space;
        int si_code;
 
-       if (notify_page_fault(regs, error_code) == NOTIFY_STOP)
+       if (notify_page_fault(regs, error_code))
                return;
 
        tsk = current;

diff --git a/include/asm-s390/kdebug.h b/include/asm-s390/kdebug.h
index 1b50f89..d2d7ad2 100644 (file)
--- a/include/asm-s390/kdebug.h
+++ b/include/asm-s390/kdebug.h
@@ -22,8 +22,21 @@ struct die_args {
  */
 extern int register_die_notifier(struct notifier_block *);
 extern int unregister_die_notifier(struct notifier_block *);
-extern int register_page_fault_notifier(struct notifier_block *);
-extern int unregister_page_fault_notifier(struct notifier_block *);
+
+/*
+ * These are only here because kprobes.c wants them to implement a
+ * blatant layering violation. Will hopefully go away soon once all
+ * architectures are updated.
+ */
+static inline int register_page_fault_notifier(struct notifier_block *nb)
+{
+       return 0;
+}
+static inline int unregister_page_fault_notifier(struct notifier_block *nb)
+{
+       return 0;
+}
+
 extern struct atomic_notifier_head s390die_chain;
 
 enum die_val {
@@ -39,7 +52,6 @@ enum die_val {
        DIE_GPF,
        DIE_CALL,
        DIE_NMI_IPI,
-       DIE_PAGE_FAULT,
 };
 
 static inline int notify_die(enum die_val val, const char *str,

diff --git a/include/asm-s390/kprobes.h b/include/asm-s390/kprobes.h
index b847ff0..830fe4c 100644 (file)
--- a/include/asm-s390/kprobes.h
+++ b/include/asm-s390/kprobes.h
@@ -97,18 +97,10 @@ void kretprobe_trampoline(void);
 int  is_prohibited_opcode(kprobe_opcode_t *instruction);
 void get_instruction_type(struct arch_specific_insn *ainsn);
 
+int kprobe_fault_handler(struct pt_regs *regs, int trapnr);
+int kprobe_exceptions_notify(struct notifier_block *self,
+       unsigned long val, void *data);
+
 #define flush_insn_slot(p)     do { } while (0)
 
 #endif /* _ASM_S390_KPROBES_H */
-
-#ifdef CONFIG_KPROBES
-
-extern int kprobe_exceptions_notify(struct notifier_block *self,
-                                       unsigned long val, void *data);
-#else  /* !CONFIG_KPROBES */
-static inline int kprobe_exceptions_notify(struct notifier_block *self,
-                                               unsigned long val, void *data)
-{
-       return 0;
-}
-#endif