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1 /*
2  * Performance event support for s390x
3  *
4  *  Copyright IBM Corp. 2012, 2013
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/kvm_host.h>
17 #include <linux/percpu.h>
18 #include <linux/export.h>
19 #include <linux/seq_file.h>
20 #include <linux/spinlock.h>
21 #include <linux/sysfs.h>
22 #include <asm/irq.h>
23 #include <asm/cpu_mf.h>
24 #include <asm/lowcore.h>
25 #include <asm/processor.h>
26 #include <asm/sysinfo.h>
27
28 const char *perf_pmu_name(void)
29 {
30         if (cpum_cf_avail() || cpum_sf_avail())
31                 return "CPU-Measurement Facilities (CPU-MF)";
32         return "pmu";
33 }
34 EXPORT_SYMBOL(perf_pmu_name);
35
36 int perf_num_counters(void)
37 {
38         int num = 0;
39
40         if (cpum_cf_avail())
41                 num += PERF_CPUM_CF_MAX_CTR;
42         if (cpum_sf_avail())
43                 num += PERF_CPUM_SF_MAX_CTR;
44
45         return num;
46 }
47 EXPORT_SYMBOL(perf_num_counters);
48
49 static struct kvm_s390_sie_block *sie_block(struct pt_regs *regs)
50 {
51         struct stack_frame *stack = (struct stack_frame *) regs->gprs[15];
52
53         if (!stack)
54                 return NULL;
55
56         return (struct kvm_s390_sie_block *) stack->empty1[0];
57 }
58
59 static bool is_in_guest(struct pt_regs *regs)
60 {
61         if (user_mode(regs))
62                 return false;
63 #if IS_ENABLED(CONFIG_KVM)
64         return instruction_pointer(regs) == (unsigned long) &sie_exit;
65 #else
66         return false;
67 #endif
68 }
69
70 static unsigned long guest_is_user_mode(struct pt_regs *regs)
71 {
72         return sie_block(regs)->gpsw.mask & PSW_MASK_PSTATE;
73 }
74
75 static unsigned long instruction_pointer_guest(struct pt_regs *regs)
76 {
77         return sie_block(regs)->gpsw.addr & PSW_ADDR_INSN;
78 }
79
80 unsigned long perf_instruction_pointer(struct pt_regs *regs)
81 {
82         return is_in_guest(regs) ? instruction_pointer_guest(regs)
83                                  : instruction_pointer(regs);
84 }
85
86 static unsigned long perf_misc_guest_flags(struct pt_regs *regs)
87 {
88         return guest_is_user_mode(regs) ? PERF_RECORD_MISC_GUEST_USER
89                                         : PERF_RECORD_MISC_GUEST_KERNEL;
90 }
91
92 static unsigned long perf_misc_flags_sf(struct pt_regs *regs)
93 {
94         struct perf_sf_sde_regs *sde_regs;
95         unsigned long flags;
96
97         sde_regs = (struct perf_sf_sde_regs *) &regs->int_parm_long;
98         if (sde_regs->in_guest)
99                 flags = user_mode(regs) ? PERF_RECORD_MISC_GUEST_USER
100                                         : PERF_RECORD_MISC_GUEST_KERNEL;
101         else
102                 flags = user_mode(regs) ? PERF_RECORD_MISC_USER
103                                         : PERF_RECORD_MISC_KERNEL;
104         return flags;
105 }
106
107 unsigned long perf_misc_flags(struct pt_regs *regs)
108 {
109         /* Check if the cpum_sf PMU has created the pt_regs structure.
110          * In this case, perf misc flags can be easily extracted.  Otherwise,
111          * do regular checks on the pt_regs content.
112          */
113         if (regs->int_code == 0x1407 && regs->int_parm == CPU_MF_INT_SF_PRA)
114                 if (!regs->gprs[15])
115                         return perf_misc_flags_sf(regs);
116
117         if (is_in_guest(regs))
118                 return perf_misc_guest_flags(regs);
119
120         return user_mode(regs) ? PERF_RECORD_MISC_USER
121                                : PERF_RECORD_MISC_KERNEL;
122 }
123
124 static void print_debug_cf(void)
125 {
126         struct cpumf_ctr_info cf_info;
127         int cpu = smp_processor_id();
128
129         memset(&cf_info, 0, sizeof(cf_info));
130         if (!qctri(&cf_info))
131                 pr_info("CPU[%i] CPUM_CF: ver=%u.%u A=%04x E=%04x C=%04x\n",
132                         cpu, cf_info.cfvn, cf_info.csvn,
133                         cf_info.auth_ctl, cf_info.enable_ctl, cf_info.act_ctl);
134 }
135
136 static void print_debug_sf(void)
137 {
138         struct hws_qsi_info_block si;
139         int cpu = smp_processor_id();
140
141         memset(&si, 0, sizeof(si));
142         if (qsi(&si))
143                 return;
144
145         pr_info("CPU[%i] CPUM_SF: basic=%i diag=%i min=%lu max=%lu cpu_speed=%u\n",
146                 cpu, si.as, si.ad, si.min_sampl_rate, si.max_sampl_rate,
147                 si.cpu_speed);
148
149         if (si.as)
150                 pr_info("CPU[%i] CPUM_SF: Basic-sampling: a=%i e=%i c=%i"
151                         " bsdes=%i tear=%016lx dear=%016lx\n", cpu,
152                         si.as, si.es, si.cs, si.bsdes, si.tear, si.dear);
153         if (si.ad)
154                 pr_info("CPU[%i] CPUM_SF: Diagnostic-sampling: a=%i e=%i c=%i"
155                         " dsdes=%i tear=%016lx dear=%016lx\n", cpu,
156                         si.ad, si.ed, si.cd, si.dsdes, si.tear, si.dear);
157 }
158
159 void perf_event_print_debug(void)
160 {
161         unsigned long flags;
162
163         local_irq_save(flags);
164         if (cpum_cf_avail())
165                 print_debug_cf();
166         if (cpum_sf_avail())
167                 print_debug_sf();
168         local_irq_restore(flags);
169 }
170
171 /* Service level infrastructure */
172 static void sl_print_counter(struct seq_file *m)
173 {
174         struct cpumf_ctr_info ci;
175
176         memset(&ci, 0, sizeof(ci));
177         if (qctri(&ci))
178                 return;
179
180         seq_printf(m, "CPU-MF: Counter facility: version=%u.%u "
181                    "authorization=%04x\n", ci.cfvn, ci.csvn, ci.auth_ctl);
182 }
183
184 static void sl_print_sampling(struct seq_file *m)
185 {
186         struct hws_qsi_info_block si;
187
188         memset(&si, 0, sizeof(si));
189         if (qsi(&si))
190                 return;
191
192         if (!si.as && !si.ad)
193                 return;
194
195         seq_printf(m, "CPU-MF: Sampling facility: min_rate=%lu max_rate=%lu"
196                    " cpu_speed=%u\n", si.min_sampl_rate, si.max_sampl_rate,
197                    si.cpu_speed);
198         if (si.as)
199                 seq_printf(m, "CPU-MF: Sampling facility: mode=basic"
200                            " sample_size=%u\n", si.bsdes);
201         if (si.ad)
202                 seq_printf(m, "CPU-MF: Sampling facility: mode=diagnostic"
203                            " sample_size=%u\n", si.dsdes);
204 }
205
206 static void service_level_perf_print(struct seq_file *m,
207                                      struct service_level *sl)
208 {
209         if (cpum_cf_avail())
210                 sl_print_counter(m);
211         if (cpum_sf_avail())
212                 sl_print_sampling(m);
213 }
214
215 static struct service_level service_level_perf = {
216         .seq_print = service_level_perf_print,
217 };
218
219 static int __init service_level_perf_register(void)
220 {
221         return register_service_level(&service_level_perf);
222 }
223 arch_initcall(service_level_perf_register);
224
225 /* See also arch/s390/kernel/traps.c */
226 static unsigned long __store_trace(struct perf_callchain_entry *entry,
227                                    unsigned long sp,
228                                    unsigned long low, unsigned long high)
229 {
230         struct stack_frame *sf;
231         struct pt_regs *regs;
232
233         while (1) {
234                 sp = sp & PSW_ADDR_INSN;
235                 if (sp < low || sp > high - sizeof(*sf))
236                         return sp;
237                 sf = (struct stack_frame *) sp;
238                 perf_callchain_store(entry, sf->gprs[8] & PSW_ADDR_INSN);
239                 /* Follow the backchain. */
240                 while (1) {
241                         low = sp;
242                         sp = sf->back_chain & PSW_ADDR_INSN;
243                         if (!sp)
244                                 break;
245                         if (sp <= low || sp > high - sizeof(*sf))
246                                 return sp;
247                         sf = (struct stack_frame *) sp;
248                         perf_callchain_store(entry,
249                                              sf->gprs[8] & PSW_ADDR_INSN);
250                 }
251                 /* Zero backchain detected, check for interrupt frame. */
252                 sp = (unsigned long) (sf + 1);
253                 if (sp <= low || sp > high - sizeof(*regs))
254                         return sp;
255                 regs = (struct pt_regs *) sp;
256                 perf_callchain_store(entry, sf->gprs[8] & PSW_ADDR_INSN);
257                 low = sp;
258                 sp = regs->gprs[15];
259         }
260 }
261
262 void perf_callchain_kernel(struct perf_callchain_entry *entry,
263                            struct pt_regs *regs)
264 {
265         unsigned long head;
266         struct stack_frame *head_sf;
267
268         if (user_mode(regs))
269                 return;
270
271         head = regs->gprs[15];
272         head_sf = (struct stack_frame *) head;
273
274         if (!head_sf || !head_sf->back_chain)
275                 return;
276
277         head = head_sf->back_chain;
278         head = __store_trace(entry, head, S390_lowcore.async_stack - ASYNC_SIZE,
279                              S390_lowcore.async_stack);
280
281         __store_trace(entry, head, S390_lowcore.thread_info,
282                       S390_lowcore.thread_info + THREAD_SIZE);
283 }
284
285 /* Perf defintions for PMU event attributes in sysfs */
286 ssize_t cpumf_events_sysfs_show(struct device *dev,
287                                 struct device_attribute *attr, char *page)
288 {
289         struct perf_pmu_events_attr *pmu_attr;
290
291         pmu_attr = container_of(attr, struct perf_pmu_events_attr, attr);
292         return sprintf(page, "event=0x%04llx,name=%s\n",
293                        pmu_attr->id, attr->attr.name);
294 }
295
296 /* Reserve/release functions for sharing perf hardware */
297 static DEFINE_SPINLOCK(perf_hw_owner_lock);
298 static void *perf_sampling_owner;
299
300 int perf_reserve_sampling(void)
301 {
302         int err;
303
304         err = 0;
305         spin_lock(&perf_hw_owner_lock);
306         if (perf_sampling_owner) {
307                 pr_warn("The sampling facility is already reserved by %p\n",
308                         perf_sampling_owner);
309                 err = -EBUSY;
310         } else
311                 perf_sampling_owner = __builtin_return_address(0);
312         spin_unlock(&perf_hw_owner_lock);
313         return err;
314 }
315 EXPORT_SYMBOL(perf_reserve_sampling);
316
317 void perf_release_sampling(void)
318 {
319         spin_lock(&perf_hw_owner_lock);
320         WARN_ON(!perf_sampling_owner);
321         perf_sampling_owner = NULL;
322         spin_unlock(&perf_hw_owner_lock);
323 }
324 EXPORT_SYMBOL(perf_release_sampling);