1 /*
2 * Copyright IBM Corp. 2012
3 * Author(s): Jan Glauber <jang@linux.vnet.ibm.com>
4 */
5
6 #include <linux/kernel.h>
7 #include <linux/syscalls.h>
8 #include <linux/signal.h>
9 #include <linux/mm.h>
10 #include <linux/slab.h>
11 #include <linux/init.h>
12 #include <linux/errno.h>
13 #include <linux/kernel_stat.h>
14 #include <asm/runtime_instr.h>
15 #include <asm/cpu_mf.h>
16 #include <asm/irq.h>
17
18 /* empty control block to disable RI by loading it */
19 struct runtime_instr_cb runtime_instr_empty_cb;
20
runtime_instr_avail(void)21 static int runtime_instr_avail(void)
22 {
23 return test_facility(64);
24 }
25
disable_runtime_instr(void)26 static void disable_runtime_instr(void)
27 {
28 struct pt_regs *regs = task_pt_regs(current);
29
30 load_runtime_instr_cb(&runtime_instr_empty_cb);
31
32 /*
33 * Make sure the RI bit is deleted from the PSW. If the user did not
34 * switch off RI before the system call the process will get a
35 * specification exception otherwise.
36 */
37 regs->psw.mask &= ~PSW_MASK_RI;
38 }
39
init_runtime_instr_cb(struct runtime_instr_cb * cb)40 static void init_runtime_instr_cb(struct runtime_instr_cb *cb)
41 {
42 cb->buf_limit = 0xfff;
43 cb->int_requested = 1;
44 cb->pstate = 1;
45 cb->pstate_set_buf = 1;
46 cb->pstate_sample = 1;
47 cb->pstate_collect = 1;
48 cb->key = PAGE_DEFAULT_KEY;
49 cb->valid = 1;
50 }
51
exit_thread_runtime_instr(void)52 void exit_thread_runtime_instr(void)
53 {
54 struct task_struct *task = current;
55
56 if (!task->thread.ri_cb)
57 return;
58 disable_runtime_instr();
59 kfree(task->thread.ri_cb);
60 task->thread.ri_signum = 0;
61 task->thread.ri_cb = NULL;
62 }
63
runtime_instr_int_handler(struct ext_code ext_code,unsigned int param32,unsigned long param64)64 static void runtime_instr_int_handler(struct ext_code ext_code,
65 unsigned int param32, unsigned long param64)
66 {
67 struct siginfo info;
68
69 if (!(param32 & CPU_MF_INT_RI_MASK))
70 return;
71
72 inc_irq_stat(IRQEXT_CMR);
73
74 if (!current->thread.ri_cb)
75 return;
76 if (current->thread.ri_signum < SIGRTMIN ||
77 current->thread.ri_signum > SIGRTMAX) {
78 WARN_ON_ONCE(1);
79 return;
80 }
81
82 memset(&info, 0, sizeof(info));
83 info.si_signo = current->thread.ri_signum;
84 info.si_code = SI_QUEUE;
85 if (param32 & CPU_MF_INT_RI_BUF_FULL)
86 info.si_int = ENOBUFS;
87 else if (param32 & CPU_MF_INT_RI_HALTED)
88 info.si_int = ECANCELED;
89 else
90 return; /* unknown reason */
91
92 send_sig_info(current->thread.ri_signum, &info, current);
93 }
94
SYSCALL_DEFINE2(s390_runtime_instr,int,command,int,signum)95 SYSCALL_DEFINE2(s390_runtime_instr, int, command, int, signum)
96 {
97 struct runtime_instr_cb *cb;
98
99 if (!runtime_instr_avail())
100 return -EOPNOTSUPP;
101
102 if (command == S390_RUNTIME_INSTR_STOP) {
103 preempt_disable();
104 exit_thread_runtime_instr();
105 preempt_enable();
106 return 0;
107 }
108
109 if (command != S390_RUNTIME_INSTR_START ||
110 (signum < SIGRTMIN || signum > SIGRTMAX))
111 return -EINVAL;
112
113 if (!current->thread.ri_cb) {
114 cb = kzalloc(sizeof(*cb), GFP_KERNEL);
115 if (!cb)
116 return -ENOMEM;
117 } else {
118 cb = current->thread.ri_cb;
119 memset(cb, 0, sizeof(*cb));
120 }
121
122 init_runtime_instr_cb(cb);
123 current->thread.ri_signum = signum;
124
125 /* now load the control block to make it available */
126 preempt_disable();
127 current->thread.ri_cb = cb;
128 load_runtime_instr_cb(cb);
129 preempt_enable();
130 return 0;
131 }
132
runtime_instr_init(void)133 static int __init runtime_instr_init(void)
134 {
135 int rc;
136
137 if (!runtime_instr_avail())
138 return 0;
139
140 irq_subclass_register(IRQ_SUBCLASS_MEASUREMENT_ALERT);
141 rc = register_external_irq(EXT_IRQ_MEASURE_ALERT,
142 runtime_instr_int_handler);
143 if (rc)
144 irq_subclass_unregister(IRQ_SUBCLASS_MEASUREMENT_ALERT);
145 else
146 pr_info("Runtime instrumentation facility initialized\n");
147 return rc;
148 }
149 device_initcall(runtime_instr_init);
150