s390/gs: add regset for the guarded storage broadcast control block

The guarded storage interface allows to register a control block for
each thread that is activated with the guarded storage broadcast event.
To retrieve the complete state of a process from the kernel a register
set for the stored broadcast control block is required.

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

1 files changed, 46 insertions, 0 deletions

diff --git a/arch/s390/kernel/ptrace.c b/arch/s390/kernel/ptrace.c
index c933e255b5d5..488c5bb8dc77 100644
--- a/arch/s390/kernel/ptrace.c
+++ b/arch/s390/kernel/ptrace.c
@@ -1173,8 +1173,46 @@ static int s390_gs_cb_set(struct task_struct *target,
 
 	if (!MACHINE_HAS_GS)
 		return -ENODEV;
+	if (!data) {
+		data = kzalloc(sizeof(*data), GFP_KERNEL);
+		if (!data)
+			return -ENOMEM;
+		target->thread.gs_cb = data;
+	}
+	return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
+				  data, 0, sizeof(struct gs_cb));
+}
+
+static int s390_gs_bc_get(struct task_struct *target,
+			  const struct user_regset *regset,
+			  unsigned int pos, unsigned int count,
+			  void *kbuf, void __user *ubuf)
+{
+	struct gs_cb *data = target->thread.gs_bc_cb;
+
+	if (!MACHINE_HAS_GS)
+		return -ENODEV;
 	if (!data)
 		return -ENODATA;
+	return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
+				   data, 0, sizeof(struct gs_cb));
+}
+
+static int s390_gs_bc_set(struct task_struct *target,
+			  const struct user_regset *regset,
+			  unsigned int pos, unsigned int count,
+			  const void *kbuf, const void __user *ubuf)
+{
+	struct gs_cb *data = target->thread.gs_bc_cb;
+
+	if (!MACHINE_HAS_GS)
+		return -ENODEV;
+	if (!data) {
+		data = kzalloc(sizeof(*data), GFP_KERNEL);
+		if (!data)
+			return -ENOMEM;
+		target->thread.gs_bc_cb = data;
+	}
 	return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 				  data, 0, sizeof(struct gs_cb));
 }
@@ -1244,6 +1282,14 @@ static const struct user_regset s390_regsets[] = {
 		.get = s390_gs_cb_get,
 		.set = s390_gs_cb_set,
 	},
+	{
+		.core_note_type = NT_S390_GS_BC,
+		.n = sizeof(struct gs_cb) / sizeof(__u64),
+		.size = sizeof(__u64),
+		.align = sizeof(__u64),
+		.get = s390_gs_bc_get,
+		.set = s390_gs_bc_set,
+	},
 };
 
 static const struct user_regset_view user_s390_view = {