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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
e4b8b3f3 JG |
2 | /* |
3 | * Copyright IBM Corp. 2012 | |
4 | * Author(s): Jan Glauber <jang@linux.vnet.ibm.com> | |
5 | */ | |
6 | ||
7 | #include <linux/kernel.h> | |
8 | #include <linux/syscalls.h> | |
9 | #include <linux/signal.h> | |
10 | #include <linux/mm.h> | |
11 | #include <linux/slab.h> | |
12 | #include <linux/init.h> | |
13 | #include <linux/errno.h> | |
14 | #include <linux/kernel_stat.h> | |
68db0cf1 IM |
15 | #include <linux/sched/task_stack.h> |
16 | ||
e4b8b3f3 JG |
17 | #include <asm/runtime_instr.h> |
18 | #include <asm/cpu_mf.h> | |
19 | #include <asm/irq.h> | |
20 | ||
21 | /* empty control block to disable RI by loading it */ | |
22 | struct runtime_instr_cb runtime_instr_empty_cb; | |
23 | ||
e4b8b3f3 JG |
24 | static void disable_runtime_instr(void) |
25 | { | |
26 | struct pt_regs *regs = task_pt_regs(current); | |
27 | ||
28 | load_runtime_instr_cb(&runtime_instr_empty_cb); | |
29 | ||
30 | /* | |
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. | |
34 | */ | |
35 | regs->psw.mask &= ~PSW_MASK_RI; | |
36 | } | |
37 | ||
38 | static void init_runtime_instr_cb(struct runtime_instr_cb *cb) | |
39 | { | |
40 | cb->buf_limit = 0xfff; | |
e4b8b3f3 JG |
41 | cb->pstate = 1; |
42 | cb->pstate_set_buf = 1; | |
43 | cb->pstate_sample = 1; | |
44 | cb->pstate_collect = 1; | |
45 | cb->key = PAGE_DEFAULT_KEY; | |
46 | cb->valid = 1; | |
47 | } | |
48 | ||
49 | void exit_thread_runtime_instr(void) | |
50 | { | |
51 | struct task_struct *task = current; | |
52 | ||
53 | if (!task->thread.ri_cb) | |
54 | return; | |
55 | disable_runtime_instr(); | |
56 | kfree(task->thread.ri_cb); | |
e4b8b3f3 JG |
57 | task->thread.ri_cb = NULL; |
58 | } | |
59 | ||
b38feccd | 60 | SYSCALL_DEFINE1(s390_runtime_instr, int, command) |
e4b8b3f3 JG |
61 | { |
62 | struct runtime_instr_cb *cb; | |
63 | ||
b38feccd | 64 | if (!test_facility(64)) |
e4b8b3f3 JG |
65 | return -EOPNOTSUPP; |
66 | ||
67 | if (command == S390_RUNTIME_INSTR_STOP) { | |
68 | preempt_disable(); | |
69 | exit_thread_runtime_instr(); | |
70 | preempt_enable(); | |
71 | return 0; | |
72 | } | |
73 | ||
b38feccd | 74 | if (command != S390_RUNTIME_INSTR_START) |
e4b8b3f3 JG |
75 | return -EINVAL; |
76 | ||
77 | if (!current->thread.ri_cb) { | |
78 | cb = kzalloc(sizeof(*cb), GFP_KERNEL); | |
79 | if (!cb) | |
80 | return -ENOMEM; | |
81 | } else { | |
82 | cb = current->thread.ri_cb; | |
83 | memset(cb, 0, sizeof(*cb)); | |
84 | } | |
85 | ||
86 | init_runtime_instr_cb(cb); | |
e4b8b3f3 JG |
87 | |
88 | /* now load the control block to make it available */ | |
89 | preempt_disable(); | |
90 | current->thread.ri_cb = cb; | |
91 | load_runtime_instr_cb(cb); | |
92 | preempt_enable(); | |
93 | return 0; | |
94 | } |