[PATCH] kprobes: fix single-step out of line - take2

Now that PPC64 has no-execute support, here is a second try to fix the
single step out of line during kprobe execution.  Kprobes on x86_64 already
solved this problem by allocating an executable page and using it as the
scratch area for stepping out of line.  Reuse that.

Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

3 files changed, 4 insertions, 1 deletions

diff --git a/include/asm-ia64/kprobes.h b/include/asm-ia64/kprobes.h
index 7b700035e36d..25d8b1edfcba 100644
--- a/include/asm-ia64/kprobes.h
+++ b/include/asm-ia64/kprobes.h
@@ -28,6 +28,7 @@
 #include <linux/ptrace.h>
 #include <asm/break.h>
 
+#define MAX_INSN_SIZE   16
 #define BREAK_INST      (long)(__IA64_BREAK_KPROBE << 6)
 
 typedef union cmp_inst {
diff --git a/include/asm-ppc64/kprobes.h b/include/asm-ppc64/kprobes.h
index 19b468bed059..790cf7c52774 100644
--- a/include/asm-ppc64/kprobes.h
+++ b/include/asm-ppc64/kprobes.h
@@ -45,7 +45,7 @@ typedef unsigned int kprobe_opcode_t;
 /* Architecture specific copy of original instruction */
 struct arch_specific_insn {
         /* copy of original instruction */
-        kprobe_opcode_t insn[MAX_INSN_SIZE];
+        kprobe_opcode_t *insn;
 };
 
 #ifdef CONFIG_KPROBES
diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h
index 5e1a7b0d7b3f..d304d4579856 100644
--- a/include/linux/kprobes.h
+++ b/include/linux/kprobes.h
@@ -177,6 +177,8 @@ extern void arch_arm_kprobe(struct kprobe *p);
 extern void arch_disarm_kprobe(struct kprobe *p);
 extern void arch_remove_kprobe(struct kprobe *p);
 extern void show_registers(struct pt_regs *regs);
+extern kprobe_opcode_t *get_insn_slot(void);
+extern void free_insn_slot(kprobe_opcode_t *slot);
 
 /* Get the kprobe at this addr (if any).  Must have called lock_kprobes */
 struct kprobe *get_kprobe(void *addr);