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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
20#include "../../../drivers/oprofile/oprof.h"
21
22extern void s390_backtrace(struct pt_regs * const regs, unsigned int depth);
23
24#ifdef CONFIG_64BIT
25
26#include "hwsampler.h"
27#include "op_counter.h"
28
29#define DEFAULT_INTERVAL 4127518
30
31#define DEFAULT_SDBT_BLOCKS 1
32#define DEFAULT_SDB_BLOCKS 511
33
34static unsigned long oprofile_hw_interval = DEFAULT_INTERVAL;
35static unsigned long oprofile_min_interval;
36static unsigned long oprofile_max_interval;
37
38static unsigned long oprofile_sdbt_blocks = DEFAULT_SDBT_BLOCKS;
39static unsigned long oprofile_sdb_blocks = DEFAULT_SDB_BLOCKS;
40
41static int hwsampler_enabled;
42static int hwsampler_running; /* start_mutex must be held to change */
43static int hwsampler_available;
44
45static struct oprofile_operations timer_ops;
46
47struct op_counter_config counter_config;
48
49enum __force_cpu_type {
50 reserved = 0, /* do not force */
51 timer,
52};
53static int force_cpu_type;
54
55static int set_cpu_type(const char *str, struct kernel_param *kp)
56{
57 if (!strcmp(str, "timer")) {
58 force_cpu_type = timer;
59 printk(KERN_INFO "oprofile: forcing timer to be returned "
60 "as cpu type\n");
61 } else {
62 force_cpu_type = 0;
63 }
64
65 return 0;
66}
67module_param_call(cpu_type, set_cpu_type, NULL, NULL, 0);
68MODULE_PARM_DESC(cpu_type, "Force legacy basic mode sampling"
69 "(report cpu_type \"timer\"");
70
71static int __oprofile_hwsampler_start(void)
72{
73 int retval;
74
75 retval = hwsampler_allocate(oprofile_sdbt_blocks, oprofile_sdb_blocks);
76 if (retval)
77 return retval;
78
79 retval = hwsampler_start_all(oprofile_hw_interval);
80 if (retval)
81 hwsampler_deallocate();
82
83 return retval;
84}
85
86static int oprofile_hwsampler_start(void)
87{
88 int retval;
89
90 hwsampler_running = hwsampler_enabled;
91
92 if (!hwsampler_running)
93 return timer_ops.start();
94
95 retval = perf_reserve_sampling();
96 if (retval)
97 return retval;
98
99 retval = __oprofile_hwsampler_start();
100 if (retval)
101 perf_release_sampling();
102
103 return retval;
104}
105
106static void oprofile_hwsampler_stop(void)
107{
108 if (!hwsampler_running) {
109 timer_ops.stop();
110 return;
111 }
112
113 hwsampler_stop_all();
114 hwsampler_deallocate();
115 perf_release_sampling();
116 return;
117}
118
119/*
120 * File ops used for:
121 * /dev/oprofile/0/enabled
122 * /dev/oprofile/hwsampling/hwsampler (cpu_type = timer)
123 */
124
125static ssize_t hwsampler_read(struct file *file, char __user *buf,
126 size_t count, loff_t *offset)
127{
128 return oprofilefs_ulong_to_user(hwsampler_enabled, buf, count, offset);
129}
130
131static ssize_t hwsampler_write(struct file *file, char const __user *buf,
132 size_t count, loff_t *offset)
133{
134 unsigned long val;
135 int retval;
136
137 if (*offset)
138 return -EINVAL;
139
140 retval = oprofilefs_ulong_from_user(&val, buf, count);
141 if (retval <= 0)
142 return retval;
143
144 if (val != 0 && val != 1)
145 return -EINVAL;
146
147 if (oprofile_started)
148 /*
149 * save to do without locking as we set
150 * hwsampler_running in start() when start_mutex is
151 * held
152 */
153 return -EBUSY;
154
155 hwsampler_enabled = val;
156
157 return count;
158}
159
160static const struct file_operations hwsampler_fops = {
161 .read = hwsampler_read,
162 .write = hwsampler_write,
163};
164
165/*
166 * File ops used for:
167 * /dev/oprofile/0/count
168 * /dev/oprofile/hwsampling/hw_interval (cpu_type = timer)
169 *
170 * Make sure that the value is within the hardware range.
171 */
172
173static ssize_t hw_interval_read(struct file *file, char __user *buf,
174 size_t count, loff_t *offset)
175{
176 return oprofilefs_ulong_to_user(oprofile_hw_interval, buf,
177 count, offset);
178}
179
180static ssize_t hw_interval_write(struct file *file, char const __user *buf,
181 size_t count, loff_t *offset)
182{
183 unsigned long val;
184 int retval;
185
186 if (*offset)
187 return -EINVAL;
188 retval = oprofilefs_ulong_from_user(&val, buf, count);
189 if (retval <= 0)
190 return retval;
191 if (val < oprofile_min_interval)
192 oprofile_hw_interval = oprofile_min_interval;
193 else if (val > oprofile_max_interval)
194 oprofile_hw_interval = oprofile_max_interval;
195 else
196 oprofile_hw_interval = val;
197
198 return count;
199}
200
201static const struct file_operations hw_interval_fops = {
202 .read = hw_interval_read,
203 .write = hw_interval_write,
204};
205
206/*
207 * File ops used for:
208 * /dev/oprofile/0/event
209 * Only a single event with number 0 is supported with this counter.
210 *
211 * /dev/oprofile/0/unit_mask
212 * This is a dummy file needed by the user space tools.
213 * No value other than 0 is accepted or returned.
214 */
215
216static ssize_t hwsampler_zero_read(struct file *file, char __user *buf,
217 size_t count, loff_t *offset)
218{
219 return oprofilefs_ulong_to_user(0, buf, count, offset);
220}
221
222static ssize_t hwsampler_zero_write(struct file *file, char const __user *buf,
223 size_t count, loff_t *offset)
224{
225 unsigned long val;
226 int retval;
227
228 if (*offset)
229 return -EINVAL;
230
231 retval = oprofilefs_ulong_from_user(&val, buf, count);
232 if (retval <= 0)
233 return retval;
234 if (val != 0)
235 return -EINVAL;
236 return count;
237}
238
239static const struct file_operations zero_fops = {
240 .read = hwsampler_zero_read,
241 .write = hwsampler_zero_write,
242};
243
244/* /dev/oprofile/0/kernel file ops. */
245
246static ssize_t hwsampler_kernel_read(struct file *file, char __user *buf,
247 size_t count, loff_t *offset)
248{
249 return oprofilefs_ulong_to_user(counter_config.kernel,
250 buf, count, offset);
251}
252
253static ssize_t hwsampler_kernel_write(struct file *file, char const __user *buf,
254 size_t count, loff_t *offset)
255{
256 unsigned long val;
257 int retval;
258
259 if (*offset)
260 return -EINVAL;
261
262 retval = oprofilefs_ulong_from_user(&val, buf, count);
263 if (retval <= 0)
264 return retval;
265
266 if (val != 0 && val != 1)
267 return -EINVAL;
268
269 counter_config.kernel = val;
270
271 return count;
272}
273
274static const struct file_operations kernel_fops = {
275 .read = hwsampler_kernel_read,
276 .write = hwsampler_kernel_write,
277};
278
279/* /dev/oprofile/0/user file ops. */
280
281static ssize_t hwsampler_user_read(struct file *file, char __user *buf,
282 size_t count, loff_t *offset)
283{
284 return oprofilefs_ulong_to_user(counter_config.user,
285 buf, count, offset);
286}
287
288static ssize_t hwsampler_user_write(struct file *file, char const __user *buf,
289 size_t count, loff_t *offset)
290{
291 unsigned long val;
292 int retval;
293
294 if (*offset)
295 return -EINVAL;
296
297 retval = oprofilefs_ulong_from_user(&val, buf, count);
298 if (retval <= 0)
299 return retval;
300
301 if (val != 0 && val != 1)
302 return -EINVAL;
303
304 counter_config.user = val;
305
306 return count;
307}
308
309static const struct file_operations user_fops = {
310 .read = hwsampler_user_read,
311 .write = hwsampler_user_write,
312};
313
314
315/*
316 * File ops used for: /dev/oprofile/timer/enabled
317 * The value always has to be the inverted value of hwsampler_enabled. So
318 * no separate variable is created. That way we do not need locking.
319 */
320
321static ssize_t timer_enabled_read(struct file *file, char __user *buf,
322 size_t count, loff_t *offset)
323{
324 return oprofilefs_ulong_to_user(!hwsampler_enabled, buf, count, offset);
325}
326
327static ssize_t timer_enabled_write(struct file *file, char const __user *buf,
328 size_t count, loff_t *offset)
329{
330 unsigned long val;
331 int retval;
332
333 if (*offset)
334 return -EINVAL;
335
336 retval = oprofilefs_ulong_from_user(&val, buf, count);
337 if (retval <= 0)
338 return retval;
339
340 if (val != 0 && val != 1)
341 return -EINVAL;
342
343 /* Timer cannot be disabled without having hardware sampling. */
344 if (val == 0 && !hwsampler_available)
345 return -EINVAL;
346
347 if (oprofile_started)
348 /*
349 * save to do without locking as we set
350 * hwsampler_running in start() when start_mutex is
351 * held
352 */
353 return -EBUSY;
354
355 hwsampler_enabled = !val;
356
357 return count;
358}
359
360static const struct file_operations timer_enabled_fops = {
361 .read = timer_enabled_read,
362 .write = timer_enabled_write,
363};
364
365
366static int oprofile_create_hwsampling_files(struct dentry *root)
367{
368 struct dentry *dir;
369
370 dir = oprofilefs_mkdir(root, "timer");
371 if (!dir)
372 return -EINVAL;
373
374 oprofilefs_create_file(dir, "enabled", &timer_enabled_fops);
375
376 if (!hwsampler_available)
377 return 0;
378
379 /* reinitialize default values */
380 hwsampler_enabled = 1;
381 counter_config.kernel = 1;
382 counter_config.user = 1;
383
384 if (!force_cpu_type) {
385 /*
386 * Create the counter file system. A single virtual
387 * counter is created which can be used to
388 * enable/disable hardware sampling dynamically from
389 * user space. The user space will configure a single
390 * counter with a single event. The value of 'event'
391 * and 'unit_mask' are not evaluated by the kernel code
392 * and can only be set to 0.
393 */
394
395 dir = oprofilefs_mkdir(root, "0");
396 if (!dir)
397 return -EINVAL;
398
399 oprofilefs_create_file(dir, "enabled", &hwsampler_fops);
400 oprofilefs_create_file(dir, "event", &zero_fops);
401 oprofilefs_create_file(dir, "count", &hw_interval_fops);
402 oprofilefs_create_file(dir, "unit_mask", &zero_fops);
403 oprofilefs_create_file(dir, "kernel", &kernel_fops);
404 oprofilefs_create_file(dir, "user", &user_fops);
405 oprofilefs_create_ulong(dir, "hw_sdbt_blocks",
406 &oprofile_sdbt_blocks);
407
408 } else {
409 /*
410 * Hardware sampling can be used but the cpu_type is
411 * forced to timer in order to deal with legacy user
412 * space tools. The /dev/oprofile/hwsampling fs is
413 * provided in that case.
414 */
415 dir = oprofilefs_mkdir(root, "hwsampling");
416 if (!dir)
417 return -EINVAL;
418
419 oprofilefs_create_file(dir, "hwsampler",
420 &hwsampler_fops);
421 oprofilefs_create_file(dir, "hw_interval",
422 &hw_interval_fops);
423 oprofilefs_create_ro_ulong(dir, "hw_min_interval",
424 &oprofile_min_interval);
425 oprofilefs_create_ro_ulong(dir, "hw_max_interval",
426 &oprofile_max_interval);
427 oprofilefs_create_ulong(dir, "hw_sdbt_blocks",
428 &oprofile_sdbt_blocks);
429 }
430 return 0;
431}
432
433static int oprofile_hwsampler_init(struct oprofile_operations *ops)
434{
435 /*
436 * Initialize the timer mode infrastructure as well in order
437 * to be able to switch back dynamically. oprofile_timer_init
438 * is not supposed to fail.
439 */
440 if (oprofile_timer_init(ops))
441 BUG();
442
443 memcpy(&timer_ops, ops, sizeof(timer_ops));
444 ops->create_files = oprofile_create_hwsampling_files;
445
446 /*
447 * If the user space tools do not support newer cpu types,
448 * the force_cpu_type module parameter
449 * can be used to always return \"timer\" as cpu type.
450 */
451 if (force_cpu_type != timer) {
452 struct cpuid id;
453
454 get_cpu_id (&id);
455
456 switch (id.machine) {
457 case 0x2097: case 0x2098: ops->cpu_type = "s390/z10"; break;
458 case 0x2817: case 0x2818: ops->cpu_type = "s390/z196"; break;
459 case 0x2827: case 0x2828: ops->cpu_type = "s390/zEC12"; break;
460 default: return -ENODEV;
461 }
462 }
463
464 if (hwsampler_setup())
465 return -ENODEV;
466
467 /*
468 * Query the range for the sampling interval from the
469 * hardware.
470 */
471 oprofile_min_interval = hwsampler_query_min_interval();
472 if (oprofile_min_interval == 0)
473 return -ENODEV;
474 oprofile_max_interval = hwsampler_query_max_interval();
475 if (oprofile_max_interval == 0)
476 return -ENODEV;
477
478 /* The initial value should be sane */
479 if (oprofile_hw_interval < oprofile_min_interval)
480 oprofile_hw_interval = oprofile_min_interval;
481 if (oprofile_hw_interval > oprofile_max_interval)
482 oprofile_hw_interval = oprofile_max_interval;
483
484 printk(KERN_INFO "oprofile: System z hardware sampling "
485 "facility found.\n");
486
487 ops->start = oprofile_hwsampler_start;
488 ops->stop = oprofile_hwsampler_stop;
489
490 return 0;
491}
492
493static void oprofile_hwsampler_exit(void)
494{
495 hwsampler_shutdown();
496}
497
498#endif /* CONFIG_64BIT */
499
500int __init oprofile_arch_init(struct oprofile_operations *ops)
501{
502 ops->backtrace = s390_backtrace;
503
504#ifdef CONFIG_64BIT
505
506 /*
507 * -ENODEV is not reported to the caller. The module itself
508 * will use the timer mode sampling as fallback and this is
509 * always available.
510 */
511 hwsampler_available = oprofile_hwsampler_init(ops) == 0;
512
513 return 0;
514#else
515 return -ENODEV;
516#endif
517}
518
519void oprofile_arch_exit(void)
520{
521#ifdef CONFIG_64BIT
522 oprofile_hwsampler_exit();
523#endif
524}