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>
diff --git a/arch/s390/include/asm/ptrace.h b/arch/s390/include/asm/ptrace.h
index 9c82ceb..f4783c0 100644
--- a/arch/s390/include/asm/ptrace.h
+++ b/arch/s390/include/asm/ptrace.h
@@ -83,6 +83,7 @@
* 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 d2e53d6..3ccd71b 100644
--- a/arch/s390/include/asm/thread_info.h
+++ b/arch/s390/include/asm/thread_info.h
@@ -92,6 +92,7 @@
#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 7e0b498..a150f4f 100644
--- a/arch/s390/include/uapi/asm/ptrace.h
+++ b/arch/s390/include/uapi/asm/ptrace.h
@@ -403,6 +403,12 @@
#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
*/
diff --git a/arch/s390/kernel/ptrace.c b/arch/s390/kernel/ptrace.c
index f6be608..4ac8fafe 100644
--- a/arch/s390/kernel/ptrace.c
+++ b/arch/s390/kernel/ptrace.c
@@ -85,7 +85,10 @@
/* merge TIF_SINGLE_STEP into user specified PER registers. */
if (test_tsk_thread_flag(task, TIF_SINGLE_STEP)) {
- new.control |= PER_EVENT_IFETCH;
+ if (test_tsk_thread_flag(task, TIF_BLOCK_STEP))
+ new.control |= PER_EVENT_BRANCH;
+ else
+ new.control |= PER_EVENT_IFETCH;
#ifdef CONFIG_64BIT
new.control |= PER_CONTROL_SUSPENSION;
new.control |= PER_EVENT_TRANSACTION_END;
@@ -107,14 +110,22 @@
void user_enable_single_step(struct task_struct *task)
{
+ clear_tsk_thread_flag(task, TIF_BLOCK_STEP);
set_tsk_thread_flag(task, TIF_SINGLE_STEP);
}
void user_disable_single_step(struct task_struct *task)
{
+ clear_tsk_thread_flag(task, TIF_BLOCK_STEP);
clear_tsk_thread_flag(task, TIF_SINGLE_STEP);
}
+void user_enable_block_step(struct task_struct *task)
+{
+ set_tsk_thread_flag(task, TIF_SINGLE_STEP);
+ set_tsk_thread_flag(task, TIF_BLOCK_STEP);
+}
+
/*
* Called by kernel/ptrace.c when detaching..
*
