kernel/arch/s390/oprofile/init.c

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