[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, 1 insertions, 0 deletions

diff --git a/include/linux/elf.h b/include/linux/elf.h
index 597858418051..4d608014753a 100644
--- a/include/linux/elf.h
+++ b/include/linux/elf.h
@@ -394,6 +394,7 @@ typedef struct elf64_shdr {
 #define NT_S390_TODPREG 0x303           /* s390 TOD programmable register */
 #define NT_S390_CTRS    0x304           /* s390 control registers */
 #define NT_S390_PREFIX  0x305           /* s390 prefix register */
+#define NT_S390_LAST_BREAK      0x306   /* s390 breaking event address */
 
 
 /* Note header in a PT_NOTE section */