[S390] add breaking event address for user space

Copy the last breaking event address from the lowcore to a new
field in the thread_struct on each system entry. Add a new
ptrace request PTRACE_GET_LAST_BREAK and a new utrace regset
REGSET_LAST_BREAK to query the last breaking event.

This is useful for debugging wild branches in user space code.

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

1 files changed, 2 insertions, 1 deletions

diff --git a/arch/s390/include/asm/ptrace.h b/arch/s390/include/asm/ptrace.h
index fef9b33cdd59..e2c218dc68a6 100644
--- a/arch/s390/include/asm/ptrace.h
+++ b/arch/s390/include/asm/ptrace.h
@@ -328,8 +328,8 @@ struct pt_regs
         psw_t psw;
         unsigned long gprs[NUM_GPRS];
         unsigned long orig_gpr2;
-        unsigned short svcnr;
         unsigned short ilc;
+        unsigned short svcnr;
 };
 #endif
 
@@ -436,6 +436,7 @@ typedef struct
 #define PTRACE_PEEKDATA_AREA          0x5003
 #define PTRACE_POKETEXT_AREA          0x5004
 #define PTRACE_POKEDATA_AREA          0x5005
+#define PTRACE_GET_LAST_BREAK         0x5006
 
 /*
  * PT_PROT definition is loosely based on hppa bsd definition in