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 static void disable_runtime_instr(void)
26 struct pt_regs
*regs
= task_pt_regs(current
);
28 load_runtime_instr_cb(&runtime_instr_empty_cb
);
31 * Make sure the RI bit is deleted from the PSW. If the user did not
32 * switch off RI before the system call the process will get a
33 * specification exception otherwise.
35 regs
->psw
.mask
&= ~PSW_MASK_RI
;
38 static void init_runtime_instr_cb(struct runtime_instr_cb
*cb
)
40 cb
->buf_limit
= 0xfff;
42 cb
->pstate_set_buf
= 1;
43 cb
->pstate_sample
= 1;
44 cb
->pstate_collect
= 1;
45 cb
->key
= PAGE_DEFAULT_KEY
;
49 void exit_thread_runtime_instr(void)
51 struct task_struct
*task
= current
;
53 if (!task
->thread
.ri_cb
)
55 disable_runtime_instr();
56 kfree(task
->thread
.ri_cb
);
57 task
->thread
.ri_cb
= NULL
;
60 SYSCALL_DEFINE1(s390_runtime_instr
, int, command
)
62 struct runtime_instr_cb
*cb
;
64 if (!test_facility(64))
67 if (command
== S390_RUNTIME_INSTR_STOP
) {
69 exit_thread_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
);