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1/*
2 * S390 Version
3 * Copyright IBM Corp. 2002, 2011
4 * Author(s): Thomas Spatzier (tspat@de.ibm.com)
5 * Author(s): Mahesh Salgaonkar (mahesh@linux.vnet.ibm.com)
6 * Author(s): Heinz Graalfs (graalfs@linux.vnet.ibm.com)
7 * Author(s): Andreas Krebbel (krebbel@linux.vnet.ibm.com)
8 *
9 * @remark Copyright 2002-2011 OProfile authors
10 */
11
12#include <linux/oprofile.h>
13#include <linux/perf_event.h>
14#include <linux/init.h>
15#include <linux/errno.h>
16#include <linux/fs.h>
17#include <linux/module.h>
18#include <asm/processor.h>
19#include <asm/perf_event.h>
20
21#include "../../../drivers/oprofile/oprof.h"
22
23#include "hwsampler.h"
24#include "op_counter.h"
25
26#define DEFAULT_INTERVAL 4127518
27
28#define DEFAULT_SDBT_BLOCKS 1
29#define DEFAULT_SDB_BLOCKS 511
30
31static unsigned long oprofile_hw_interval = DEFAULT_INTERVAL;
32static unsigned long oprofile_min_interval;
33static unsigned long oprofile_max_interval;
34
35static unsigned long oprofile_sdbt_blocks = DEFAULT_SDBT_BLOCKS;
36static unsigned long oprofile_sdb_blocks = DEFAULT_SDB_BLOCKS;
37
38static int hwsampler_enabled;
39static int hwsampler_running; /* start_mutex must be held to change */
40static int hwsampler_available;
41
42static struct oprofile_operations timer_ops;
43
44struct op_counter_config counter_config;
45
46enum __force_cpu_type {
47 reserved = 0, /* do not force */
48 timer,
49};
50static int force_cpu_type;
51
52static int set_cpu_type(const char *str, struct kernel_param *kp)
53{
54 if (!strcmp(str, "timer")) {
55 force_cpu_type = timer;
56 printk(KERN_INFO "oprofile: forcing timer to be returned "
57 "as cpu type\n");
58 } else {
59 force_cpu_type = 0;
60 }
61
62 return 0;
63}
64module_param_call(cpu_type, set_cpu_type, NULL, NULL, 0);
65MODULE_PARM_DESC(cpu_type, "Force legacy basic mode sampling"
66 "(report cpu_type \"timer\"");
67
68static int __oprofile_hwsampler_start(void)
69{
70 int retval;
71
72 retval = hwsampler_allocate(oprofile_sdbt_blocks, oprofile_sdb_blocks);
73 if (retval)
74 return retval;
75
76 retval = hwsampler_start_all(oprofile_hw_interval);
77 if (retval)
78 hwsampler_deallocate();
79
80 return retval;
81}
82
83static int oprofile_hwsampler_start(void)
84{
85 int retval;
86
87 hwsampler_running = hwsampler_enabled;
88
89 if (!hwsampler_running)
90 return timer_ops.start();
91
92 retval = perf_reserve_sampling();
93 if (retval)
94 return retval;
95
96 retval = __oprofile_hwsampler_start();
97 if (retval)
98 perf_release_sampling();
99
100 return retval;
101}
102
103static void oprofile_hwsampler_stop(void)
104{
105 if (!hwsampler_running) {
106 timer_ops.stop();
107 return;
108 }
109
110 hwsampler_stop_all();
111 hwsampler_deallocate();
112 perf_release_sampling();
113 return;
114}
115
116/*
117 * File ops used for:
118 * /dev/oprofile/0/enabled
119 * /dev/oprofile/hwsampling/hwsampler (cpu_type = timer)
120 */
121
122static ssize_t hwsampler_read(struct file *file, char __user *buf,
123 size_t count, loff_t *offset)
124{
125 return oprofilefs_ulong_to_user(hwsampler_enabled, buf, count, offset);
126}
127
128static ssize_t hwsampler_write(struct file *file, char const __user *buf,
129 size_t count, loff_t *offset)
130{
131 unsigned long val;
132 int retval;
133
134 if (*offset)
135 return -EINVAL;
136
137 retval = oprofilefs_ulong_from_user(&val, buf, count);
138 if (retval <= 0)
139 return retval;
140
141 if (val != 0 && val != 1)
142 return -EINVAL;
143
144 if (oprofile_started)
145 /*
146 * save to do without locking as we set
147 * hwsampler_running in start() when start_mutex is
148 * held
149 */
150 return -EBUSY;
151
152 hwsampler_enabled = val;
153
154 return count;
155}
156
157static const struct file_operations hwsampler_fops = {
158 .read = hwsampler_read,
159 .write = hwsampler_write,
160};
161
162/*
163 * File ops used for:
164 * /dev/oprofile/0/count
165 * /dev/oprofile/hwsampling/hw_interval (cpu_type = timer)
166 *
167 * Make sure that the value is within the hardware range.
168 */
169
170static ssize_t hw_interval_read(struct file *file, char __user *buf,
171 size_t count, loff_t *offset)
172{
173 return oprofilefs_ulong_to_user(oprofile_hw_interval, buf,
174 count, offset);
175}
176
177static ssize_t hw_interval_write(struct file *file, char const __user *buf,
178 size_t count, loff_t *offset)
179{
180 unsigned long val;
181 int retval;
182
183 if (*offset)
184 return -EINVAL;
185 retval = oprofilefs_ulong_from_user(&val, buf, count);
186 if (retval <= 0)
187 return retval;
188 if (val < oprofile_min_interval)
189 oprofile_hw_interval = oprofile_min_interval;
190 else if (val > oprofile_max_interval)
191 oprofile_hw_interval = oprofile_max_interval;
192 else
193 oprofile_hw_interval = val;
194
195 return count;
196}
197
198static const struct file_operations hw_interval_fops = {
199 .read = hw_interval_read,
200 .write = hw_interval_write,
201};
202
203/*
204 * File ops used for:
205 * /dev/oprofile/0/event
206 * Only a single event with number 0 is supported with this counter.
207 *
208 * /dev/oprofile/0/unit_mask
209 * This is a dummy file needed by the user space tools.
210 * No value other than 0 is accepted or returned.
211 */
212
213static ssize_t hwsampler_zero_read(struct file *file, char __user *buf,
214 size_t count, loff_t *offset)
215{
216 return oprofilefs_ulong_to_user(0, buf, count, offset);
217}
218
219static ssize_t hwsampler_zero_write(struct file *file, char const __user *buf,
220 size_t count, loff_t *offset)
221{
222 unsigned long val;
223 int retval;
224
225 if (*offset)
226 return -EINVAL;
227
228 retval = oprofilefs_ulong_from_user(&val, buf, count);
229 if (retval <= 0)
230 return retval;
231 if (val != 0)
232 return -EINVAL;
233 return count;
234}
235
236static const struct file_operations zero_fops = {
237 .read = hwsampler_zero_read,
238 .write = hwsampler_zero_write,
239};
240
241/* /dev/oprofile/0/kernel file ops. */
242
243static ssize_t hwsampler_kernel_read(struct file *file, char __user *buf,
244 size_t count, loff_t *offset)
245{
246 return oprofilefs_ulong_to_user(counter_config.kernel,
247 buf, count, offset);
248}
249
250static ssize_t hwsampler_kernel_write(struct file *file, char const __user *buf,
251 size_t count, loff_t *offset)
252{
253 unsigned long val;
254 int retval;
255
256 if (*offset)
257 return -EINVAL;
258
259 retval = oprofilefs_ulong_from_user(&val, buf, count);
260 if (retval <= 0)
261 return retval;
262
263 if (val != 0 && val != 1)
264 return -EINVAL;
265
266 counter_config.kernel = val;
267
268 return count;
269}
270
271static const struct file_operations kernel_fops = {
272 .read = hwsampler_kernel_read,
273 .write = hwsampler_kernel_write,
274};
275
276/* /dev/oprofile/0/user file ops. */
277
278static ssize_t hwsampler_user_read(struct file *file, char __user *buf,
279 size_t count, loff_t *offset)
280{
281 return oprofilefs_ulong_to_user(counter_config.user,
282 buf, count, offset);
283}
284
285static ssize_t hwsampler_user_write(struct file *file, char const __user *buf,
286 size_t count, loff_t *offset)
287{
288 unsigned long val;
289 int retval;
290
291 if (*offset)
292 return -EINVAL;
293
294 retval = oprofilefs_ulong_from_user(&val, buf, count);
295 if (retval <= 0)
296 return retval;
297
298 if (val != 0 && val != 1)
299 return -EINVAL;
300
301 counter_config.user = val;
302
303 return count;
304}
305
306static const struct file_operations user_fops = {
307 .read = hwsampler_user_read,
308 .write = hwsampler_user_write,
309};
310
311
312/*
313 * File ops used for: /dev/oprofile/timer/enabled
314 * The value always has to be the inverted value of hwsampler_enabled. So
315 * no separate variable is created. That way we do not need locking.
316 */
317
318static ssize_t timer_enabled_read(struct file *file, char __user *buf,
319 size_t count, loff_t *offset)
320{
321 return oprofilefs_ulong_to_user(!hwsampler_enabled, buf, count, offset);
322}
323
324static ssize_t timer_enabled_write(struct file *file, char const __user *buf,
325 size_t count, loff_t *offset)
326{
327 unsigned long val;
328 int retval;
329
330 if (*offset)
331 return -EINVAL;
332
333 retval = oprofilefs_ulong_from_user(&val, buf, count);
334 if (retval <= 0)
335 return retval;
336
337 if (val != 0 && val != 1)
338 return -EINVAL;
339
340 /* Timer cannot be disabled without having hardware sampling. */
341 if (val == 0 && !hwsampler_available)
342 return -EINVAL;
343
344 if (oprofile_started)
345 /*
346 * save to do without locking as we set
347 * hwsampler_running in start() when start_mutex is
348 * held
349 */
350 return -EBUSY;
351
352 hwsampler_enabled = !val;
353
354 return count;
355}
356
357static const struct file_operations timer_enabled_fops = {
358 .read = timer_enabled_read,
359 .write = timer_enabled_write,
360};
361
362
363static int oprofile_create_hwsampling_files(struct dentry *root)
364{
365 struct dentry *dir;
366
367 dir = oprofilefs_mkdir(root, "timer");
368 if (!dir)
369 return -EINVAL;
370
371 oprofilefs_create_file(dir, "enabled", &timer_enabled_fops);
372
373 if (!hwsampler_available)
374 return 0;
375
376 /* reinitialize default values */
377 hwsampler_enabled = 1;
378 counter_config.kernel = 1;
379 counter_config.user = 1;
380
381 if (!force_cpu_type) {
382 /*
383 * Create the counter file system. A single virtual
384 * counter is created which can be used to
385 * enable/disable hardware sampling dynamically from
386 * user space. The user space will configure a single
387 * counter with a single event. The value of 'event'
388 * and 'unit_mask' are not evaluated by the kernel code
389 * and can only be set to 0.
390 */
391
392 dir = oprofilefs_mkdir(root, "0");
393 if (!dir)
394 return -EINVAL;
395
396 oprofilefs_create_file(dir, "enabled", &hwsampler_fops);
397 oprofilefs_create_file(dir, "event", &zero_fops);
398 oprofilefs_create_file(dir, "count", &hw_interval_fops);
399 oprofilefs_create_file(dir, "unit_mask", &zero_fops);
400 oprofilefs_create_file(dir, "kernel", &kernel_fops);
401 oprofilefs_create_file(dir, "user", &user_fops);
402 oprofilefs_create_ulong(dir, "hw_sdbt_blocks",
403 &oprofile_sdbt_blocks);
404
405 } else {
406 /*
407 * Hardware sampling can be used but the cpu_type is
408 * forced to timer in order to deal with legacy user
409 * space tools. The /dev/oprofile/hwsampling fs is
410 * provided in that case.
411 */
412 dir = oprofilefs_mkdir(root, "hwsampling");
413 if (!dir)
414 return -EINVAL;
415
416 oprofilefs_create_file(dir, "hwsampler",
417 &hwsampler_fops);
418 oprofilefs_create_file(dir, "hw_interval",
419 &hw_interval_fops);
420 oprofilefs_create_ro_ulong(dir, "hw_min_interval",
421 &oprofile_min_interval);
422 oprofilefs_create_ro_ulong(dir, "hw_max_interval",
423 &oprofile_max_interval);
424 oprofilefs_create_ulong(dir, "hw_sdbt_blocks",
425 &oprofile_sdbt_blocks);
426 }
427 return 0;
428}
429
430static int oprofile_hwsampler_init(struct oprofile_operations *ops)
431{
432 /*
433 * Initialize the timer mode infrastructure as well in order
434 * to be able to switch back dynamically. oprofile_timer_init
435 * is not supposed to fail.
436 */
437 if (oprofile_timer_init(ops))
438 BUG();
439
440 memcpy(&timer_ops, ops, sizeof(timer_ops));
441 ops->create_files = oprofile_create_hwsampling_files;
442
443 /*
444 * If the user space tools do not support newer cpu types,
445 * the force_cpu_type module parameter
446 * can be used to always return \"timer\" as cpu type.
447 */
448 if (force_cpu_type != timer) {
449 struct cpuid id;
450
451 get_cpu_id (&id);
452
453 switch (id.machine) {
454 case 0x2097: case 0x2098: ops->cpu_type = "s390/z10"; break;
455 case 0x2817: case 0x2818: ops->cpu_type = "s390/z196"; break;
456 case 0x2827: case 0x2828: ops->cpu_type = "s390/zEC12"; break;
457 case 0x2964: case 0x2965: ops->cpu_type = "s390/z13"; break;
458 default: return -ENODEV;
459 }
460 }
461
462 if (hwsampler_setup())
463 return -ENODEV;
464
465 /*
466 * Query the range for the sampling interval from the
467 * hardware.
468 */
469 oprofile_min_interval = hwsampler_query_min_interval();
470 if (oprofile_min_interval == 0)
471 return -ENODEV;
472 oprofile_max_interval = hwsampler_query_max_interval();
473 if (oprofile_max_interval == 0)
474 return -ENODEV;
475
476 /* The initial value should be sane */
477 if (oprofile_hw_interval < oprofile_min_interval)
478 oprofile_hw_interval = oprofile_min_interval;
479 if (oprofile_hw_interval > oprofile_max_interval)
480 oprofile_hw_interval = oprofile_max_interval;
481
482 printk(KERN_INFO "oprofile: System z hardware sampling "
483 "facility found.\n");
484
485 ops->start = oprofile_hwsampler_start;
486 ops->stop = oprofile_hwsampler_stop;
487
488 return 0;
489}
490
491static void oprofile_hwsampler_exit(void)
492{
493 hwsampler_shutdown();
494}
495
496static int __s390_backtrace(void *data, unsigned long address)
497{
498 unsigned int *depth = data;
499
500 if (*depth == 0)
501 return 1;
502 (*depth)--;
503 oprofile_add_trace(address);
504 return 0;
505}
506
507static void s390_backtrace(struct pt_regs *regs, unsigned int depth)
508{
509 if (user_mode(regs))
510 return;
511 dump_trace(__s390_backtrace, &depth, NULL, regs->gprs[15]);
512}
513
514int __init oprofile_arch_init(struct oprofile_operations *ops)
515{
516 ops->backtrace = s390_backtrace;
517
518 /*
519 * -ENODEV is not reported to the caller. The module itself
520 * will use the timer mode sampling as fallback and this is
521 * always available.
522 */
523 hwsampler_available = oprofile_hwsampler_init(ops) == 0;
524
525 return 0;
526}
527
528void oprofile_arch_exit(void)
529{
530 oprofile_hwsampler_exit();
531}