ptrace: powerpc: implement user_single_step_siginfo()

Suggested by Roland.

Implement user_single_step_siginfo() for powerpc.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Roland McGrath <roland@redhat.com>
Cc: <linux-arch@vger.kernel.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/powerpc/include/asm/ptrace.h b/arch/powerpc/include/asm/ptrace.h
index 8c34149..cbd759e 100644
--- a/arch/powerpc/include/asm/ptrace.h
+++ b/arch/powerpc/include/asm/ptrace.h
@@ -140,6 +140,8 @@
 extern void user_enable_block_step(struct task_struct *);
 extern void user_disable_single_step(struct task_struct *);
 
+#define ARCH_HAS_USER_SINGLE_STEP_INFO
+
 #endif /* __ASSEMBLY__ */
 
 #endif /* __KERNEL__ */
diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index 804f0f3..d069ff8 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -174,6 +174,15 @@
 	return 0;
 }
 
+void user_single_step_siginfo(struct task_struct *tsk,
+				struct pt_regs *regs, siginfo_t *info)
+{
+	memset(info, 0, sizeof(*info));
+	info->si_signo = SIGTRAP;
+	info->si_code = TRAP_TRACE;
+	info->si_addr = (void __user *)regs->nip;
+}
+
 void _exception(int signr, struct pt_regs *regs, int code, unsigned long addr)
 {
 	siginfo_t info;