2007-05-04 16:52:20

by Martin Schwidefsky

Subject: [patch 1/9] get rid of kprobes notifier call chain.

From: Christoph Hellwig <[email protected]>

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 <[email protected]>
Signed-off-by: Martin Schwidefsky <[email protected]>
---

arch/s390/kernel/kprobes.c | 3 +--
arch/s390/mm/fault.c | 38 ++++++++++++--------------------------
include/asm-s390/kdebug.h | 18 +++++++++++++++---
include/asm-s390/kprobes.h | 16 ++++------------
4 files changed, 32 insertions(+), 43 deletions(-)

Index: quilt-2.6/arch/s390/kernel/kprobes.c
===================================================================
--- quilt-2.6.orig/arch/s390/kernel/kprobes.c 2007-05-04 18:48:36.000000000 +0200
+++ quilt-2.6/arch/s390/kernel/kprobes.c 2007-05-04 18:50:14.000000000 +0200
@@ -516,7 +516,7 @@
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 @@
ret = NOTIFY_STOP;
break;
case DIE_TRAP:
- case DIE_PAGE_FAULT:
/* kprobe_running() needs smp_processor_id() */
preempt_disable();
if (kprobe_running() &&
Index: quilt-2.6/arch/s390/mm/fault.c
===================================================================
--- quilt-2.6.orig/arch/s390/mm/fault.c 2007-05-04 18:48:36.000000000 +0200
+++ quilt-2.6/arch/s390/mm/fault.c 2007-05-04 18:50:14.000000000 +0200
@@ -52,38 +52,24 @@
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)
+static inline int notify_page_fault(struct pt_regs *regs, long err)
{
- return atomic_notifier_chain_unregister(&notify_page_fault_chain, nb);
-}
+ int ret = 0;

-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);
-}
+ /* kprobe_running() needs smp_processor_id() */
+ if (!user_mode(regs)) {
+ preempt_disable();
+ if (kprobe_running() && kprobe_fault_handler(regs, 14))
+ ret = 1;
+ preempt_enable();
+ }

-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;
+ 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 @@
int space;
int si_code;

- if (notify_page_fault(regs, error_code) == NOTIFY_STOP)
+ if (notify_page_fault(regs, error_code))
return;

tsk = current;
Index: quilt-2.6/include/asm-s390/kdebug.h
===================================================================
--- quilt-2.6.orig/include/asm-s390/kdebug.h 2007-05-04 18:48:36.000000000 +0200
+++ quilt-2.6/include/asm-s390/kdebug.h 2007-05-04 18:50:14.000000000 +0200
@@ -22,8 +22,21 @@
*/
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 @@
DIE_GPF,
DIE_CALL,
DIE_NMI_IPI,
- DIE_PAGE_FAULT,
};

static inline int notify_die(enum die_val val, const char *str,
Index: quilt-2.6/include/asm-s390/kprobes.h
===================================================================
--- quilt-2.6.orig/include/asm-s390/kprobes.h 2007-05-04 18:48:36.000000000 +0200
+++ quilt-2.6/include/asm-s390/kprobes.h 2007-05-04 18:50:14.000000000 +0200
@@ -97,18 +97,10 @@
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

--
blue skies,
Martin.

"Reality continues to ruin my life." - Calvin.