[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/arch/s390/kernel/asm-offsets.c b/arch/s390/kernel/asm-offsets.c
index 44a4336d9a33..d9b490a2716e 100644
--- a/arch/s390/kernel/asm-offsets.c
+++ b/arch/s390/kernel/asm-offsets.c
@@ -39,6 +39,7 @@ int main(void)
         DEFINE(__TI_precount, offsetof(struct thread_info, preempt_count));
         DEFINE(__TI_user_timer, offsetof(struct thread_info, user_timer));
         DEFINE(__TI_system_timer, offsetof(struct thread_info, system_timer));
+        DEFINE(__TI_last_break, offsetof(struct thread_info, last_break));
         BLANK();
         DEFINE(__PT_ARGS, offsetof(struct pt_regs, args));
         DEFINE(__PT_PSW, offsetof(struct pt_regs, psw));