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 op_arm_enabled;
  42 static DEFINE_MUTEX(op_arm_mutex);
  43
  44 static struct op_counter_config *counter_config;
  45 static struct perf_event **perf_events[nr_cpumask_bits];
  46 static int perf_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 < perf_num_counters; ++id)
  58                 if (perf_events[cpu][id] == event)
  59                         break;
  60
  61         if (id != perf_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 op_arm_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 < perf_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 op_arm_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 < perf_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 op_arm_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 < perf_num_counters; ++event)
 154                         op_destroy_counter(cpu, event);
 155 }
 156
 157
 158 static char *op_name_from_perf_id(enum arm_perf_pmu_ids id)
 159 {
 160         switch (id) {
 161         case ARM_PERF_PMU_ID_XSCALE1:
 162                 return "arm/xscale1";
 163         case ARM_PERF_PMU_ID_XSCALE2:
 164                 return "arm/xscale2";
 165         case ARM_PERF_PMU_ID_V6:
 166                 return "arm/armv6";
 167         case ARM_PERF_PMU_ID_V6MP:
 168                 return "arm/mpcore";
 169         case ARM_PERF_PMU_ID_CA8:
 170                 return "arm/armv7";
 171         case ARM_PERF_PMU_ID_CA9:
 172                 return "arm/armv7-ca9";
 173         default:
 174                 return NULL;
 175         }
 176 }
 177
 178 static int op_arm_create_files(struct super_block *sb, struct dentry *root)
 179 {
 180         unsigned int i;
 181
 182         for (i = 0; i < perf_num_counters; i++) {
 183                 struct dentry *dir;
 184                 char buf[4];
 185
 186                 snprintf(buf, sizeof buf, "%d", i);
 187                 dir = oprofilefs_mkdir(sb, root, buf);
 188                 oprofilefs_create_ulong(sb, dir, "enabled", &counter_config[i].enabled);
 189                 oprofilefs_create_ulong(sb, dir, "event", &counter_config[i].event);
 190                 oprofilefs_create_ulong(sb, dir, "count", &counter_config[i].count);
 191                 oprofilefs_create_ulong(sb, dir, "unit_mask", &counter_config[i].unit_mask);
 192                 oprofilefs_create_ulong(sb, dir, "kernel", &counter_config[i].kernel);
 193                 oprofilefs_create_ulong(sb, dir, "user", &counter_config[i].user);
 194         }
 195
 196         return 0;
 197 }
 198
 199 static int op_arm_setup(void)
 200 {
 201         spin_lock(&oprofilefs_lock);
 202         op_perf_setup();
 203         spin_unlock(&oprofilefs_lock);
 204         return 0;
 205 }
 206
 207 static int op_arm_start(void)
 208 {
 209         int ret = -EBUSY;
 210
 211         mutex_lock(&op_arm_mutex);
 212         if (!op_arm_enabled) {
 213                 ret = 0;
 214                 op_perf_start();
 215                 op_arm_enabled = 1;
 216         }
 217         mutex_unlock(&op_arm_mutex);
 218         return ret;
 219 }
 220
 221 static void op_arm_stop(void)
 222 {
 223         mutex_lock(&op_arm_mutex);
 224         if (op_arm_enabled)
 225                 op_perf_stop();
 226         op_arm_enabled = 0;
 227         mutex_unlock(&op_arm_mutex);
 228 }
 229
 230 #ifdef CONFIG_PM
 231 static int op_arm_suspend(struct platform_device *dev, pm_message_t state)
 232 {
 233         mutex_lock(&op_arm_mutex);
 234         if (op_arm_enabled)
 235                 op_perf_stop();
 236         mutex_unlock(&op_arm_mutex);
 237         return 0;
 238 }
 239
 240 static int op_arm_resume(struct platform_device *dev)
 241 {
 242         mutex_lock(&op_arm_mutex);
 243         if (op_arm_enabled && op_perf_start())
 244                 op_arm_enabled = 0;
 245         mutex_unlock(&op_arm_mutex);
 246         return 0;
 247 }
 248
 249 static struct platform_driver oprofile_driver = {
 250         .driver         = {
 251                 .name           = "arm-oprofile",
 252         },
 253         .resume         = op_arm_resume,
 254         .suspend        = op_arm_suspend,
 255 };
 256
 257 static struct platform_device *oprofile_pdev;
 258
 259 static int __init init_driverfs(void)
 260 {
 261         int ret;
 262
 263         ret = platform_driver_register(&oprofile_driver);
 264         if (ret)
 265                 goto out;
 266
 267         oprofile_pdev = platform_device_register_simple(
 268                                 oprofile_driver.driver.name, 0, NULL, 0);
 269         if (IS_ERR(oprofile_pdev)) {
 270                 ret = PTR_ERR(oprofile_pdev);
 271                 platform_driver_unregister(&oprofile_driver);
 272         }
 273
 274 out:
 275         return ret;
 276 }
 277
 278 static void __exit exit_driverfs(void)
 279 {
 280         platform_device_unregister(oprofile_pdev);
 281         platform_driver_unregister(&oprofile_driver);
 282 }
 283 #else
 284 static int __init init_driverfs(void) { return 0; }
 285 #define exit_driverfs() do { } while (0)
 286 #endif /* CONFIG_PM */
 287
 288 static int report_trace(struct stackframe *frame, void *d)
 289 {
 290         unsigned int *depth = d;
 291
 292         if (*depth) {
 293                 oprofile_add_trace(frame->pc);
 294                 (*depth)--;
 295         }
 296
 297         return *depth == 0;
 298 }
 299
 300 /*
 301  * The registers we're interested in are at the end of the variable
 302  * length saved register structure. The fp points at the end of this
 303  * structure so the address of this struct is:
 304  * (struct frame_tail *)(xxx->fp)-1
 305  */
 306 struct frame_tail {
 307         struct frame_tail *fp;
 308         unsigned long sp;
 309         unsigned long lr;
 310 } __attribute__((packed));
 311
 312 static struct frame_tail* user_backtrace(struct frame_tail *tail)
 313 {
 314         struct frame_tail buftail[2];
 315
 316         /* Also check accessibility of one struct frame_tail beyond */
 317         if (!access_ok(VERIFY_READ, tail, sizeof(buftail)))
 318                 return NULL;
 319         if (__copy_from_user_inatomic(buftail, tail, sizeof(buftail)))
 320                 return NULL;
 321
 322         oprofile_add_trace(buftail[0].lr);
 323
 324         /* frame pointers should strictly progress back up the stack
 325          * (towards higher addresses) */
 326         if (tail >= buftail[0].fp)
 327                 return NULL;
 328
 329         return buftail[0].fp-1;
 330 }
 331
 332 static void arm_backtrace(struct pt_regs * const regs, unsigned int depth)
 333 {
 334         struct frame_tail *tail = ((struct frame_tail *) regs->ARM_fp) - 1;
 335
 336         if (!user_mode(regs)) {
 337                 struct stackframe frame;
 338                 frame.fp = regs->ARM_fp;
 339                 frame.sp = regs->ARM_sp;
 340                 frame.lr = regs->ARM_lr;
 341                 frame.pc = regs->ARM_pc;
 342                 walk_stackframe(&frame, report_trace, &depth);
 343                 return;
 344         }
 345
 346         while (depth-- && tail && !((unsigned long) tail & 3))
 347                 tail = user_backtrace(tail);
 348 }
 349
 350 int __init oprofile_arch_init(struct oprofile_operations *ops)
 351 {
 352         int cpu, ret = 0;
 353
 354         perf_num_counters = armpmu_get_max_events();
 355
 356         counter_config = kcalloc(perf_num_counters,
 357                         sizeof(struct op_counter_config), GFP_KERNEL);
 358
 359         if (!counter_config) {
 360                 pr_info("oprofile: failed to allocate %d "
 361                                 "counters\n", perf_num_counters);
 362                 ret = -ENOMEM;
 363                 goto out;
 364         }
 365
 366         ret = init_driverfs();
 367         if (ret)
 368                 goto out;
 369
 370         for_each_possible_cpu(cpu) {
 371                 perf_events[cpu] = kcalloc(perf_num_counters,
 372                                 sizeof(struct perf_event *), GFP_KERNEL);
 373                 if (!perf_events[cpu]) {
 374                         pr_info("oprofile: failed to allocate %d perf events "
 375                                         "for cpu %d\n", perf_num_counters, cpu);
 376                         ret = -ENOMEM;
 377                         goto out;
 378                 }
 379         }
 380
 381         ops->backtrace          = arm_backtrace;
 382         ops->create_files       = op_arm_create_files;
 383         ops->setup              = op_arm_setup;
 384         ops->start              = op_arm_start;
 385         ops->stop               = op_arm_stop;
 386         ops->shutdown           = op_arm_stop;
 387         ops->cpu_type           = op_name_from_perf_id(armpmu_get_pmu_id());
 388
 389         if (!ops->cpu_type)
 390                 ret = -ENODEV;
 391         else
 392                 pr_info("oprofile: using %s\n", ops->cpu_type);
 393
 394 out:
 395         if (ret) {
 396                 for_each_possible_cpu(cpu)
 397                         kfree(perf_events[cpu]);
 398                 kfree(counter_config);
 399         }
 400
 401         return ret;
 402 }
 403
 404 void __exit oprofile_arch_exit(void)
 405 {
 406         int cpu, id;
 407         struct perf_event *event;
 408
 409         for_each_possible_cpu(cpu) {
 410                 for (id = 0; id < perf_num_counters; ++id) {
 411                         event = perf_events[cpu][id];
 412                         if (event)
 413                                 perf_event_release_kernel(event);
 414                 }
 415
 416                 kfree(perf_events[cpu]);
 417         }
 418
 419         kfree(counter_config);
 420         exit_driverfs();
 421 }
 422 #else
 423 int __init oprofile_arch_init(struct oprofile_operations *ops)
 424 {
 425         pr_info("oprofile: hardware counters not available\n");
 426         return -ENODEV;
 427 }
 428 void __exit oprofile_arch_exit(void) {}
 429 #endif /* CONFIG_HW_PERF_EVENTS */