arch/arm/oprofile/common.c

   1 /**
   2  * @file common.c
   3  *
   4  * @remark Copyright 2004 Oprofile Authors
   5  * @remark Copyright 2010 ARM Ltd.
   6  * @remark Read the file COPYING
   7  *
   8  * @author Zwane Mwaikambo
   9  * @author Will Deacon [move to perf]
  10  */
  11
  12 #include <linux/cpumask.h>
  13 #include <linux/err.h>
  14 #include <linux/errno.h>
  15 #include <linux/init.h>
  16 #include <linux/mutex.h>
  17 #include <linux/oprofile.h>
  18 #include <linux/perf_event.h>
  19 #include <linux/platform_device.h>
  20 #include <linux/slab.h>
  21 #include <asm/stacktrace.h>
  22 #include <linux/uaccess.h>
  23
  24 #include <asm/perf_event.h>
  25 #include <asm/ptrace.h>
  26
  27 #ifdef CONFIG_HW_PERF_EVENTS
  28 /*
  29  * Per performance monitor configuration as set via oprofilefs.
  30  */
  31 struct op_counter_config {
  32         unsigned long count;
  33         unsigned long enabled;
  34         unsigned long event;
  35         unsigned long unit_mask;
  36         unsigned long kernel;
  37         unsigned long user;
  38         struct perf_event_attr attr;
  39 };
  40
  41 static int oprofile_perf_enabled;
  42 static DEFINE_MUTEX(oprofile_perf_mutex);
  43
  44 static struct op_counter_config *counter_config;
  45 static struct perf_event **perf_events[nr_cpumask_bits];
  46 static int num_counters;
  47
  48 /*
  49  * Overflow callback for oprofile.
  50  */
  51 static void op_overflow_handler(struct perf_event *event, int unused,
  52                         struct perf_sample_data *data, struct pt_regs *regs)
  53 {
  54         int id;
  55         u32 cpu = smp_processor_id();
  56
  57         for (id = 0; id < num_counters; ++id)
  58                 if (perf_events[cpu][id] == event)
  59                         break;
  60
  61         if (id != num_counters)
  62                 oprofile_add_sample(regs, id);
  63         else
  64                 pr_warning("oprofile: ignoring spurious overflow "
  65                                 "on cpu %u\n", cpu);
  66 }
  67
  68 /*
  69  * Called by oprofile_perf_setup to create perf attributes to mirror the oprofile
  70  * settings in counter_config. Attributes are created as `pinned' events and
  71  * so are permanently scheduled on the PMU.
  72  */
  73 static void op_perf_setup(void)
  74 {
  75         int i;
  76         u32 size = sizeof(struct perf_event_attr);
  77         struct perf_event_attr *attr;
  78
  79         for (i = 0; i < num_counters; ++i) {
  80                 attr = &counter_config[i].attr;
  81                 memset(attr, 0, size);
  82                 attr->type              = PERF_TYPE_RAW;
  83                 attr->size              = size;
  84                 attr->config            = counter_config[i].event;
  85                 attr->sample_period     = counter_config[i].count;
  86                 attr->pinned            = 1;
  87         }
  88 }
  89
  90 static int op_create_counter(int cpu, int event)
  91 {
  92         int ret = 0;
  93         struct perf_event *pevent;
  94
  95         if (!counter_config[event].enabled || (perf_events[cpu][event] != NULL))
  96                 return ret;
  97
  98         pevent = perf_event_create_kernel_counter(&counter_config[event].attr,
  99                                                   cpu, -1,
 100                                                   op_overflow_handler);
 101
 102         if (IS_ERR(pevent)) {
 103                 ret = PTR_ERR(pevent);
 104         } else if (pevent->state != PERF_EVENT_STATE_ACTIVE) {
 105                 pr_warning("oprofile: failed to enable event %d "
 106                                 "on CPU %d\n", event, cpu);
 107                 ret = -EBUSY;
 108         } else {
 109                 perf_events[cpu][event] = pevent;
 110         }
 111
 112         return ret;
 113 }
 114
 115 static void op_destroy_counter(int cpu, int event)
 116 {
 117         struct perf_event *pevent = perf_events[cpu][event];
 118
 119         if (pevent) {
 120                 perf_event_release_kernel(pevent);
 121                 perf_events[cpu][event] = NULL;
 122         }
 123 }
 124
 125 /*
 126  * Called by oprofile_perf_start to create active perf events based on the
 127  * perviously configured attributes.
 128  */
 129 static int op_perf_start(void)
 130 {
 131         int cpu, event, ret = 0;
 132
 133         for_each_online_cpu(cpu) {
 134                 for (event = 0; event < num_counters; ++event) {
 135                         ret = op_create_counter(cpu, event);
 136                         if (ret)
 137                                 goto out;
 138                 }
 139         }
 140
 141 out:
 142         return ret;
 143 }
 144
 145 /*
 146  * Called by oprofile_perf_stop at the end of a profiling run.
 147  */
 148 static void op_perf_stop(void)
 149 {
 150         int cpu, event;
 151
 152         for_each_online_cpu(cpu)
 153                 for (event = 0; event < num_counters; ++event)
 154                         op_destroy_counter(cpu, event);
 155 }
 156
 157
 158 char *op_name_from_perf_id(void)
 159 {
 160         enum arm_perf_pmu_ids id = armpmu_get_pmu_id();
 161
 162         switch (id) {
 163         case ARM_PERF_PMU_ID_XSCALE1:
 164                 return "arm/xscale1";
 165         case ARM_PERF_PMU_ID_XSCALE2:
 166                 return "arm/xscale2";
 167         case ARM_PERF_PMU_ID_V6:
 168                 return "arm/armv6";
 169         case ARM_PERF_PMU_ID_V6MP:
 170                 return "arm/mpcore";
 171         case ARM_PERF_PMU_ID_CA8:
 172                 return "arm/armv7";
 173         case ARM_PERF_PMU_ID_CA9:
 174                 return "arm/armv7-ca9";
 175         default:
 176                 return NULL;
 177         }
 178 }
 179
 180 static int oprofile_perf_create_files(struct super_block *sb, struct dentry *root)
 181 {
 182         unsigned int i;
 183
 184         for (i = 0; i < num_counters; i++) {
 185                 struct dentry *dir;
 186                 char buf[4];
 187
 188                 snprintf(buf, sizeof buf, "%d", i);
 189                 dir = oprofilefs_mkdir(sb, root, buf);
 190                 oprofilefs_create_ulong(sb, dir, "enabled", &counter_config[i].enabled);
 191                 oprofilefs_create_ulong(sb, dir, "event", &counter_config[i].event);
 192                 oprofilefs_create_ulong(sb, dir, "count", &counter_config[i].count);
 193                 oprofilefs_create_ulong(sb, dir, "unit_mask", &counter_config[i].unit_mask);
 194                 oprofilefs_create_ulong(sb, dir, "kernel", &counter_config[i].kernel);
 195                 oprofilefs_create_ulong(sb, dir, "user", &counter_config[i].user);
 196         }
 197
 198         return 0;
 199 }
 200
 201 static int oprofile_perf_setup(void)
 202 {
 203         spin_lock(&oprofilefs_lock);
 204         op_perf_setup();
 205         spin_unlock(&oprofilefs_lock);
 206         return 0;
 207 }
 208
 209 static int oprofile_perf_start(void)
 210 {
 211         int ret = -EBUSY;
 212
 213         mutex_lock(&oprofile_perf_mutex);
 214         if (!oprofile_perf_enabled) {
 215                 ret = 0;
 216                 op_perf_start();
 217                 oprofile_perf_enabled = 1;
 218         }
 219         mutex_unlock(&oprofile_perf_mutex);
 220         return ret;
 221 }
 222
 223 static void oprofile_perf_stop(void)
 224 {
 225         mutex_lock(&oprofile_perf_mutex);
 226         if (oprofile_perf_enabled)
 227                 op_perf_stop();
 228         oprofile_perf_enabled = 0;
 229         mutex_unlock(&oprofile_perf_mutex);
 230 }
 231
 232 #ifdef CONFIG_PM
 233 static int oprofile_perf_suspend(struct platform_device *dev, pm_message_t state)
 234 {
 235         mutex_lock(&oprofile_perf_mutex);
 236         if (oprofile_perf_enabled)
 237                 op_perf_stop();
 238         mutex_unlock(&oprofile_perf_mutex);
 239         return 0;
 240 }
 241
 242 static int oprofile_perf_resume(struct platform_device *dev)
 243 {
 244         mutex_lock(&oprofile_perf_mutex);
 245         if (oprofile_perf_enabled && op_perf_start())
 246                 oprofile_perf_enabled = 0;
 247         mutex_unlock(&oprofile_perf_mutex);
 248         return 0;
 249 }
 250
 251 static struct platform_driver oprofile_driver = {
 252         .driver         = {
 253                 .name           = "oprofile-perf",
 254         },
 255         .resume         = oprofile_perf_resume,
 256         .suspend        = oprofile_perf_suspend,
 257 };
 258
 259 static struct platform_device *oprofile_pdev;
 260
 261 static int __init init_driverfs(void)
 262 {
 263         int ret;
 264
 265         ret = platform_driver_register(&oprofile_driver);
 266         if (ret)
 267                 goto out;
 268
 269         oprofile_pdev = platform_device_register_simple(
 270                                 oprofile_driver.driver.name, 0, NULL, 0);
 271         if (IS_ERR(oprofile_pdev)) {
 272                 ret = PTR_ERR(oprofile_pdev);
 273                 platform_driver_unregister(&oprofile_driver);
 274         }
 275
 276 out:
 277         return ret;
 278 }
 279
 280 static void __exit exit_driverfs(void)
 281 {
 282         platform_device_unregister(oprofile_pdev);
 283         platform_driver_unregister(&oprofile_driver);
 284 }
 285 #else
 286 static int __init init_driverfs(void) { return 0; }
 287 #define exit_driverfs() do { } while (0)
 288 #endif /* CONFIG_PM */
 289
 290 static int report_trace(struct stackframe *frame, void *d)
 291 {
 292         unsigned int *depth = d;
 293
 294         if (*depth) {
 295                 oprofile_add_trace(frame->pc);
 296                 (*depth)--;
 297         }
 298
 299         return *depth == 0;
 300 }
 301
 302 /*
 303  * The registers we're interested in are at the end of the variable
 304  * length saved register structure. The fp points at the end of this
 305  * structure so the address of this struct is:
 306  * (struct frame_tail *)(xxx->fp)-1
 307  */
 308 struct frame_tail {
 309         struct frame_tail *fp;
 310         unsigned long sp;
 311         unsigned long lr;
 312 } __attribute__((packed));
 313
 314 static struct frame_tail* user_backtrace(struct frame_tail *tail)
 315 {
 316         struct frame_tail buftail[2];
 317
 318         /* Also check accessibility of one struct frame_tail beyond */
 319         if (!access_ok(VERIFY_READ, tail, sizeof(buftail)))
 320                 return NULL;
 321         if (__copy_from_user_inatomic(buftail, tail, sizeof(buftail)))
 322                 return NULL;
 323
 324         oprofile_add_trace(buftail[0].lr);
 325
 326         /* frame pointers should strictly progress back up the stack
 327          * (towards higher addresses) */
 328         if (tail >= buftail[0].fp)
 329                 return NULL;
 330
 331         return buftail[0].fp-1;
 332 }
 333
 334 static void arm_backtrace(struct pt_regs * const regs, unsigned int depth)
 335 {
 336         struct frame_tail *tail = ((struct frame_tail *) regs->ARM_fp) - 1;
 337
 338         if (!user_mode(regs)) {
 339                 struct stackframe frame;
 340                 frame.fp = regs->ARM_fp;
 341                 frame.sp = regs->ARM_sp;
 342                 frame.lr = regs->ARM_lr;
 343                 frame.pc = regs->ARM_pc;
 344                 walk_stackframe(&frame, report_trace, &depth);
 345                 return;
 346         }
 347
 348         while (depth-- && tail && !((unsigned long) tail & 3))
 349                 tail = user_backtrace(tail);
 350 }
 351
 352 int __init oprofile_perf_init(struct oprofile_operations *ops)
 353 {
 354         int cpu, ret = 0;
 355
 356         memset(&perf_events, 0, sizeof(perf_events));
 357
 358         num_counters = perf_num_counters();
 359         if (num_counters <= 0) {
 360                 pr_info("oprofile: no performance counters\n");
 361                 ret = -ENODEV;
 362                 goto out;
 363         }
 364
 365         counter_config = kcalloc(num_counters,
 366                         sizeof(struct op_counter_config), GFP_KERNEL);
 367
 368         if (!counter_config) {
 369                 pr_info("oprofile: failed to allocate %d "
 370                                 "counters\n", num_counters);
 371                 ret = -ENOMEM;
 372                 goto out;
 373         }
 374
 375         ret = init_driverfs();
 376         if (ret)
 377                 goto out;
 378
 379         for_each_possible_cpu(cpu) {
 380                 perf_events[cpu] = kcalloc(num_counters,
 381                                 sizeof(struct perf_event *), GFP_KERNEL);
 382                 if (!perf_events[cpu]) {
 383                         pr_info("oprofile: failed to allocate %d perf events "
 384                                         "for cpu %d\n", num_counters, cpu);
 385                         ret = -ENOMEM;
 386                         goto out;
 387                 }
 388         }
 389
 390         ops->create_files       = oprofile_perf_create_files;
 391         ops->setup              = oprofile_perf_setup;
 392         ops->start              = oprofile_perf_start;
 393         ops->stop               = oprofile_perf_stop;
 394         ops->shutdown           = oprofile_perf_stop;
 395         ops->cpu_type           = op_name_from_perf_id();
 396
 397         if (!ops->cpu_type)
 398                 ret = -ENODEV;
 399         else
 400                 pr_info("oprofile: using %s\n", ops->cpu_type);
 401
 402 out:
 403         if (ret) {
 404                 for_each_possible_cpu(cpu)
 405                         kfree(perf_events[cpu]);
 406                 kfree(counter_config);
 407         }
 408
 409         return ret;
 410 }
 411
 412 int __init oprofile_arch_init(struct oprofile_operations *ops)
 413 {
 414         ops->backtrace          = arm_backtrace;
 415
 416         return oprofile_perf_init(ops);
 417 }
 418
 419 void __exit oprofile_perf_exit(void)
 420 {
 421         int cpu, id;
 422         struct perf_event *event;
 423
 424         for_each_possible_cpu(cpu) {
 425                 for (id = 0; id < num_counters; ++id) {
 426                         event = perf_events[cpu][id];
 427                         if (event)
 428                                 perf_event_release_kernel(event);
 429                 }
 430
 431                 kfree(perf_events[cpu]);
 432         }
 433
 434         kfree(counter_config);
 435         exit_driverfs();
 436 }
 437
 438 void __exit oprofile_arch_exit(void)
 439 {
 440         oprofile_perf_exit();
 441 }
 442 #else
 443 int __init oprofile_arch_init(struct oprofile_operations *ops)
 444 {
 445         pr_info("oprofile: hardware counters not available\n");
 446         return -ENODEV;
 447 }
 448 void __exit oprofile_arch_exit(void) {}
 449 #endif /* CONFIG_HW_PERF_EVENTS */