s390/ptrace: add support for PTRACE_SINGLEBLOCK

The PTRACE_SINGLEBLOCK option is used to get control whenever
the inferior has executed a successful branch. The PER option to
implement block stepping is successful-branching event, bit 32
in the PER-event mask.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

3 files changed, 8 insertions, 0 deletions

diff --git a/arch/s390/include/asm/ptrace.h b/arch/s390/include/asm/ptrace.h
index 9c82cebddabd..f4783c0b7b43 100644
--- a/arch/s390/include/asm/ptrace.h
+++ b/arch/s390/include/asm/ptrace.h
@@ -83,6 +83,7 @@ struct per_struct_kernel {
  * These are defined as per linux/ptrace.h, which see.
  */
 #define arch_has_single_step()  (1)
+#define arch_has_block_step()   (1)
 
 #define user_mode(regs) (((regs)->psw.mask & PSW_MASK_PSTATE) != 0)
 #define instruction_pointer(regs) ((regs)->psw.addr & PSW_ADDR_INSN)
diff --git a/arch/s390/include/asm/thread_info.h b/arch/s390/include/asm/thread_info.h
index d2e53d667a92..3ccd71b90345 100644
--- a/arch/s390/include/asm/thread_info.h
+++ b/arch/s390/include/asm/thread_info.h
@@ -92,6 +92,7 @@ static inline struct thread_info *current_thread_info(void)
 #define TIF_MEMDIE              18      /* is terminating due to OOM killer */
 #define TIF_RESTORE_SIGMASK     19      /* restore signal mask in do_signal() */
 #define TIF_SINGLE_STEP         20      /* This task is single stepped */
+#define TIF_BLOCK_STEP          21      /* This task is block stepped */
 
 #define _TIF_SYSCALL            (1<<TIF_SYSCALL)
 #define _TIF_NOTIFY_RESUME      (1<<TIF_NOTIFY_RESUME)
diff --git a/arch/s390/include/uapi/asm/ptrace.h b/arch/s390/include/uapi/asm/ptrace.h
index 7e0b498a2c2b..a150f4fabe43 100644
--- a/arch/s390/include/uapi/asm/ptrace.h
+++ b/arch/s390/include/uapi/asm/ptrace.h
@@ -403,6 +403,12 @@ typedef struct
 #define PTRACE_TE_ABORT_RAND          0x5011
 
 /*
+ * The numbers chosen here are somewhat arbitrary but absolutely MUST
+ * not overlap with any of the number assigned in <linux/ptrace.h>.
+ */
+#define PTRACE_SINGLEBLOCK      12      /* resume execution until next branch */
+
+/*
  * PT_PROT definition is loosely based on hppa bsd definition in
  * gdb/hppab-nat.c
  */