1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright IBM Corp. 2012
4 * Author(s): Jan Glauber <jang@linux.vnet.ibm.com>
7 #include <linux/kernel.h>
8 #include <linux/syscalls.h>
9 #include <linux/signal.h>
11 #include <linux/slab.h>
12 #include <linux/init.h>
13 #include <linux/errno.h>
14 #include <linux/kernel_stat.h>
15 #include <linux/sched/task_stack.h>
17 #include <asm/runtime_instr.h>
18 #include <asm/cpu_mf.h>
21 /* empty control block to disable RI by loading it */
22 struct runtime_instr_cb runtime_instr_empty_cb;
24 void runtime_instr_release(struct task_struct *tsk)
26 kfree(tsk->thread.ri_cb);
29 static void disable_runtime_instr(void)
31 struct task_struct *task = current;
34 if (!task->thread.ri_cb)
36 regs = task_pt_regs(task);
38 load_runtime_instr_cb(&runtime_instr_empty_cb);
39 kfree(task->thread.ri_cb);
40 task->thread.ri_cb = NULL;
44 * Make sure the RI bit is deleted from the PSW. If the user did not
45 * switch off RI before the system call the process will get a
46 * specification exception otherwise.
48 regs->psw.mask &= ~PSW_MASK_RI;
51 static void init_runtime_instr_cb(struct runtime_instr_cb *cb)
53 cb->buf_limit = 0xfff;
55 cb->pstate_set_buf = 1;
56 cb->pstate_sample = 1;
57 cb->pstate_collect = 1;
58 cb->key = PAGE_DEFAULT_KEY;
62 SYSCALL_DEFINE1(s390_runtime_instr, int, command)
64 struct runtime_instr_cb *cb;
66 if (!test_facility(64))
69 if (command == S390_RUNTIME_INSTR_STOP) {
70 disable_runtime_instr();
74 if (command != S390_RUNTIME_INSTR_START)
77 if (!current->thread.ri_cb) {
78 cb = kzalloc(sizeof(*cb), GFP_KERNEL);
82 cb = current->thread.ri_cb;
83 memset(cb, 0, sizeof(*cb));
86 init_runtime_instr_cb(cb);
88 /* now load the control block to make it available */
90 current->thread.ri_cb = cb;
91 load_runtime_instr_cb(cb);