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)
17 kfree(current->thread.gs_cb);
18 kfree(current->thread.gs_bc_cb);
19 current->thread.gs_cb = current->thread.gs_bc_cb = NULL;
22 static int gs_enable(void)
26 if (!current->thread.gs_cb) {
27 gs_cb = kzalloc(sizeof(*gs_cb), GFP_KERNEL);
34 current->thread.gs_cb = gs_cb;
40 static int gs_disable(void)
42 if (current->thread.gs_cb) {
44 kfree(current->thread.gs_cb);
45 current->thread.gs_cb = NULL;
46 __ctl_clear_bit(2, 4);
52 static int gs_set_bc_cb(struct gs_cb __user *u_gs_cb)
56 gs_cb = current->thread.gs_bc_cb;
58 gs_cb = kzalloc(sizeof(*gs_cb), GFP_KERNEL);
61 current->thread.gs_bc_cb = gs_cb;
63 if (copy_from_user(gs_cb, u_gs_cb, sizeof(*gs_cb)))
68 static int gs_clear_bc_cb(void)
72 gs_cb = current->thread.gs_bc_cb;
73 current->thread.gs_bc_cb = NULL;
78 void gs_load_bc_cb(struct pt_regs *regs)
83 clear_thread_flag(TIF_GUARDED_STORAGE);
84 gs_cb = current->thread.gs_bc_cb;
86 kfree(current->thread.gs_cb);
87 current->thread.gs_bc_cb = NULL;
90 current->thread.gs_cb = gs_cb;
95 static int gs_broadcast(void)
97 struct task_struct *sibling;
99 read_lock(&tasklist_lock);
100 for_each_thread(current, sibling) {
101 if (!sibling->thread.gs_bc_cb)
103 if (test_and_set_tsk_thread_flag(sibling, TIF_GUARDED_STORAGE))
104 kick_process(sibling);
106 read_unlock(&tasklist_lock);
110 SYSCALL_DEFINE2(s390_guarded_storage, int, command,
111 struct gs_cb __user *, gs_cb)
121 return gs_set_bc_cb(gs_cb);
123 return gs_clear_bc_cb();
125 return gs_broadcast();