Merge tag 'sh-for-linus' of git://github.com/pmundt/linux-sh
[linux-2.6.git] / arch / s390 / kernel / perf_event.c
1 /*
2  * Performance event support for s390x
3  *
4  *  Copyright IBM Corp. 2012
5  *  Author(s): Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License (version 2 only)
9  * as published by the Free Software Foundation.
10  */
11 #define KMSG_COMPONENT  "perf"
12 #define pr_fmt(fmt)     KMSG_COMPONENT ": " fmt
13
14 #include <linux/kernel.h>
15 #include <linux/perf_event.h>
16 #include <linux/percpu.h>
17 #include <linux/export.h>
18 #include <asm/system.h>
19 #include <asm/irq.h>
20 #include <asm/cpu_mf.h>
21 #include <asm/lowcore.h>
22 #include <asm/processor.h>
23
24 const char *perf_pmu_name(void)
25 {
26         if (cpum_cf_avail() || cpum_sf_avail())
27                 return "CPU-measurement facilities (CPUMF)";
28         return "pmu";
29 }
30 EXPORT_SYMBOL(perf_pmu_name);
31
32 int perf_num_counters(void)
33 {
34         int num = 0;
35
36         if (cpum_cf_avail())
37                 num += PERF_CPUM_CF_MAX_CTR;
38
39         return num;
40 }
41 EXPORT_SYMBOL(perf_num_counters);
42
43 void perf_event_print_debug(void)
44 {
45         struct cpumf_ctr_info cf_info;
46         unsigned long flags;
47         int cpu;
48
49         if (!cpum_cf_avail())
50                 return;
51
52         local_irq_save(flags);
53
54         cpu = smp_processor_id();
55         memset(&cf_info, 0, sizeof(cf_info));
56         if (!qctri(&cf_info)) {
57                 pr_info("CPU[%i] CPUM_CF: ver=%u.%u A=%04x E=%04x C=%04x\n",
58                         cpu, cf_info.cfvn, cf_info.csvn,
59                         cf_info.auth_ctl, cf_info.enable_ctl, cf_info.act_ctl);
60                 print_hex_dump_bytes("CPUMF Query: ", DUMP_PREFIX_OFFSET,
61                                      &cf_info, sizeof(cf_info));
62         }
63
64         local_irq_restore(flags);
65 }
66
67 /* See also arch/s390/kernel/traps.c */
68 static unsigned long __store_trace(struct perf_callchain_entry *entry,
69                                    unsigned long sp,
70                                    unsigned long low, unsigned long high)
71 {
72         struct stack_frame *sf;
73         struct pt_regs *regs;
74
75         while (1) {
76                 sp = sp & PSW_ADDR_INSN;
77                 if (sp < low || sp > high - sizeof(*sf))
78                         return sp;
79                 sf = (struct stack_frame *) sp;
80                 perf_callchain_store(entry, sf->gprs[8] & PSW_ADDR_INSN);
81                 /* Follow the backchain. */
82                 while (1) {
83                         low = sp;
84                         sp = sf->back_chain & PSW_ADDR_INSN;
85                         if (!sp)
86                                 break;
87                         if (sp <= low || sp > high - sizeof(*sf))
88                                 return sp;
89                         sf = (struct stack_frame *) sp;
90                         perf_callchain_store(entry,
91                                              sf->gprs[8] & PSW_ADDR_INSN);
92                 }
93                 /* Zero backchain detected, check for interrupt frame. */
94                 sp = (unsigned long) (sf + 1);
95                 if (sp <= low || sp > high - sizeof(*regs))
96                         return sp;
97                 regs = (struct pt_regs *) sp;
98                 perf_callchain_store(entry, sf->gprs[8] & PSW_ADDR_INSN);
99                 low = sp;
100                 sp = regs->gprs[15];
101         }
102 }
103
104 void perf_callchain_kernel(struct perf_callchain_entry *entry,
105                            struct pt_regs *regs)
106 {
107         unsigned long head;
108         struct stack_frame *head_sf;
109
110         if (user_mode(regs))
111                 return;
112
113         head = regs->gprs[15];
114         head_sf = (struct stack_frame *) head;
115
116         if (!head_sf || !head_sf->back_chain)
117                 return;
118
119         head = head_sf->back_chain;
120         head = __store_trace(entry, head, S390_lowcore.async_stack - ASYNC_SIZE,
121                              S390_lowcore.async_stack);
122
123         __store_trace(entry, head, S390_lowcore.thread_info,
124                       S390_lowcore.thread_info + THREAD_SIZE);
125 }