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-rw-r--r--arch/s390/kernel/guarded_storage.c128
1 files changed, 128 insertions, 0 deletions
diff --git a/arch/s390/kernel/guarded_storage.c b/arch/s390/kernel/guarded_storage.c
new file mode 100644
index 000000000..d14dd1c2e
--- /dev/null
+++ b/arch/s390/kernel/guarded_storage.c
@@ -0,0 +1,128 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright IBM Corp. 2016
+ * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
+ */
+
+#include <linux/kernel.h>
+#include <linux/syscalls.h>
+#include <linux/signal.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <asm/guarded_storage.h>
+#include "entry.h"
+
+void guarded_storage_release(struct task_struct *tsk)
+{
+ kfree(tsk->thread.gs_cb);
+ kfree(tsk->thread.gs_bc_cb);
+}
+
+static int gs_enable(void)
+{
+ struct gs_cb *gs_cb;
+
+ if (!current->thread.gs_cb) {
+ gs_cb = kzalloc(sizeof(*gs_cb), GFP_KERNEL);
+ if (!gs_cb)
+ return -ENOMEM;
+ gs_cb->gsd = 25;
+ preempt_disable();
+ __ctl_set_bit(2, 4);
+ load_gs_cb(gs_cb);
+ current->thread.gs_cb = gs_cb;
+ preempt_enable();
+ }
+ return 0;
+}
+
+static int gs_disable(void)
+{
+ if (current->thread.gs_cb) {
+ preempt_disable();
+ kfree(current->thread.gs_cb);
+ current->thread.gs_cb = NULL;
+ __ctl_clear_bit(2, 4);
+ preempt_enable();
+ }
+ return 0;
+}
+
+static int gs_set_bc_cb(struct gs_cb __user *u_gs_cb)
+{
+ struct gs_cb *gs_cb;
+
+ gs_cb = current->thread.gs_bc_cb;
+ if (!gs_cb) {
+ gs_cb = kzalloc(sizeof(*gs_cb), GFP_KERNEL);
+ if (!gs_cb)
+ return -ENOMEM;
+ current->thread.gs_bc_cb = gs_cb;
+ }
+ if (copy_from_user(gs_cb, u_gs_cb, sizeof(*gs_cb)))
+ return -EFAULT;
+ return 0;
+}
+
+static int gs_clear_bc_cb(void)
+{
+ struct gs_cb *gs_cb;
+
+ gs_cb = current->thread.gs_bc_cb;
+ current->thread.gs_bc_cb = NULL;
+ kfree(gs_cb);
+ return 0;
+}
+
+void gs_load_bc_cb(struct pt_regs *regs)
+{
+ struct gs_cb *gs_cb;
+
+ preempt_disable();
+ clear_thread_flag(TIF_GUARDED_STORAGE);
+ gs_cb = current->thread.gs_bc_cb;
+ if (gs_cb) {
+ kfree(current->thread.gs_cb);
+ current->thread.gs_bc_cb = NULL;
+ __ctl_set_bit(2, 4);
+ load_gs_cb(gs_cb);
+ current->thread.gs_cb = gs_cb;
+ }
+ preempt_enable();
+}
+
+static int gs_broadcast(void)
+{
+ struct task_struct *sibling;
+
+ read_lock(&tasklist_lock);
+ for_each_thread(current, sibling) {
+ if (!sibling->thread.gs_bc_cb)
+ continue;
+ if (test_and_set_tsk_thread_flag(sibling, TIF_GUARDED_STORAGE))
+ kick_process(sibling);
+ }
+ read_unlock(&tasklist_lock);
+ return 0;
+}
+
+SYSCALL_DEFINE2(s390_guarded_storage, int, command,
+ struct gs_cb __user *, gs_cb)
+{
+ if (!MACHINE_HAS_GS)
+ return -EOPNOTSUPP;
+ switch (command) {
+ case GS_ENABLE:
+ return gs_enable();
+ case GS_DISABLE:
+ return gs_disable();
+ case GS_SET_BC_CB:
+ return gs_set_bc_cb(gs_cb);
+ case GS_CLEAR_BC_CB:
+ return gs_clear_bc_cb();
+ case GS_BROADCAST:
+ return gs_broadcast();
+ default:
+ return -EINVAL;
+ }
+}