1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright IBM Corp. 2016
4 * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
7 #include <linux/kernel.h>
8 #include <linux/syscalls.h>
9 #include <linux/signal.h>
11 #include <linux/slab.h>
12 #include <asm/guarded_storage.h>
15 void exit_thread_gs(void)
18 kfree(current->thread.gs_cb);
19 kfree(current->thread.gs_bc_cb);
20 current->thread.gs_cb = current->thread.gs_bc_cb = NULL;
24 static int gs_enable(void)
28 if (!current->thread.gs_cb) {
29 gs_cb = kzalloc(sizeof(*gs_cb), GFP_KERNEL);
36 current->thread.gs_cb = gs_cb;
42 static int gs_disable(void)
44 if (current->thread.gs_cb) {
46 kfree(current->thread.gs_cb);
47 current->thread.gs_cb = NULL;
48 __ctl_clear_bit(2, 4);
54 static int gs_set_bc_cb(struct gs_cb __user *u_gs_cb)
58 gs_cb = current->thread.gs_bc_cb;
60 gs_cb = kzalloc(sizeof(*gs_cb), GFP_KERNEL);
63 current->thread.gs_bc_cb = gs_cb;
65 if (copy_from_user(gs_cb, u_gs_cb, sizeof(*gs_cb)))
70 static int gs_clear_bc_cb(void)
74 gs_cb = current->thread.gs_bc_cb;
75 current->thread.gs_bc_cb = NULL;
80 void gs_load_bc_cb(struct pt_regs *regs)
85 clear_thread_flag(TIF_GUARDED_STORAGE);
86 gs_cb = current->thread.gs_bc_cb;
88 kfree(current->thread.gs_cb);
89 current->thread.gs_bc_cb = NULL;
92 current->thread.gs_cb = gs_cb;
97 static int gs_broadcast(void)
99 struct task_struct *sibling;
101 read_lock(&tasklist_lock);
102 for_each_thread(current, sibling) {
103 if (!sibling->thread.gs_bc_cb)
105 if (test_and_set_tsk_thread_flag(sibling, TIF_GUARDED_STORAGE))
106 kick_process(sibling);
108 read_unlock(&tasklist_lock);
112 SYSCALL_DEFINE2(s390_guarded_storage, int, command,
113 struct gs_cb __user *, gs_cb)
123 return gs_set_bc_cb(gs_cb);
125 return gs_clear_bc_cb();
127 return gs_broadcast();