kernel/profile.c

   1 /*
   2  *  linux/kernel/profile.c
   3  */
   4
   5 #include <linux/config.h>
   6 #include <linux/module.h>
   7 #include <linux/profile.h>
   8 #include <linux/bootmem.h>
   9 #include <linux/notifier.h>
  10 #include <linux/mm.h>
  11 #include <linux/cpumask.h>
  12 #include <linux/profile.h>
  13 #include <asm/sections.h>
  14
  15 static atomic_t *prof_buffer;
  16 static unsigned long prof_len, prof_shift;
  17 static int prof_on;
  18 static cpumask_t prof_cpu_mask = CPU_MASK_ALL;
  19
  20 static int __init profile_setup(char * str)
  21 {
  22         int par;
  23
  24         if (!strncmp(str, "schedule", 8)) {
  25                 prof_on = 2;
  26                 printk(KERN_INFO "kernel schedule profiling enabled\n");
  27                 if (str[7] == ',')
  28                         str += 8;
  29         }
  30         if (get_option(&str,&par)) {
  31                 prof_shift = par;
  32                 prof_on = 1;
  33                 printk(KERN_INFO "kernel profiling enabled (shift: %ld)\n",
  34                         prof_shift);
  35         }
  36         return 1;
  37 }
  38 __setup("profile=", profile_setup);
  39
  40
  41 void __init profile_init(void)
  42 {
  43         if (!prof_on)
  44                 return;
  45
  46         /* only text is profiled */
  47         prof_len = (_etext - _stext) >> prof_shift;
  48         prof_buffer = alloc_bootmem(prof_len*sizeof(atomic_t));
  49 }
  50
  51 /* Profile event notifications */
  52
  53 #ifdef CONFIG_PROFILING
  54
  55 static DECLARE_RWSEM(profile_rwsem);
  56 static rwlock_t handoff_lock = RW_LOCK_UNLOCKED;
  57 static struct notifier_block * task_exit_notifier;
  58 static struct notifier_block * task_free_notifier;
  59 static struct notifier_block * munmap_notifier;
  60
  61 void profile_task_exit(struct task_struct * task)
  62 {
  63         down_read(&profile_rwsem);
  64         notifier_call_chain(&task_exit_notifier, 0, task);
  65         up_read(&profile_rwsem);
  66 }
  67
  68 int profile_handoff_task(struct task_struct * task)
  69 {
  70         int ret;
  71         read_lock(&handoff_lock);
  72         ret = notifier_call_chain(&task_free_notifier, 0, task);
  73         read_unlock(&handoff_lock);
  74         return (ret == NOTIFY_OK) ? 1 : 0;
  75 }
  76
  77 void profile_munmap(unsigned long addr)
  78 {
  79         down_read(&profile_rwsem);
  80         notifier_call_chain(&munmap_notifier, 0, (void *)addr);
  81         up_read(&profile_rwsem);
  82 }
  83
  84 int task_handoff_register(struct notifier_block * n)
  85 {
  86         int err = -EINVAL;
  87
  88         write_lock(&handoff_lock);
  89         err = notifier_chain_register(&task_free_notifier, n);
  90         write_unlock(&handoff_lock);
  91         return err;
  92 }
  93
  94 int task_handoff_unregister(struct notifier_block * n)
  95 {
  96         int err = -EINVAL;
  97
  98         write_lock(&handoff_lock);
  99         err = notifier_chain_unregister(&task_free_notifier, n);
 100         write_unlock(&handoff_lock);
 101         return err;
 102 }
 103
 104 int profile_event_register(enum profile_type type, struct notifier_block * n)
 105 {
 106         int err = -EINVAL;
 107
 108         down_write(&profile_rwsem);
 109
 110         switch (type) {
 111                 case PROFILE_TASK_EXIT:
 112                         err = notifier_chain_register(&task_exit_notifier, n);
 113                         break;
 114                 case PROFILE_MUNMAP:
 115                         err = notifier_chain_register(&munmap_notifier, n);
 116                         break;
 117         }
 118
 119         up_write(&profile_rwsem);
 120
 121         return err;
 122 }
 123
 124
 125 int profile_event_unregister(enum profile_type type, struct notifier_block * n)
 126 {
 127         int err = -EINVAL;
 128
 129         down_write(&profile_rwsem);
 130
 131         switch (type) {
 132                 case PROFILE_TASK_EXIT:
 133                         err = notifier_chain_unregister(&task_exit_notifier, n);
 134                         break;
 135                 case PROFILE_MUNMAP:
 136                         err = notifier_chain_unregister(&munmap_notifier, n);
 137                         break;
 138         }
 139
 140         up_write(&profile_rwsem);
 141         return err;
 142 }
 143
 144 static struct notifier_block * profile_listeners;
 145 static rwlock_t profile_lock = RW_LOCK_UNLOCKED;
 146
 147 int register_profile_notifier(struct notifier_block * nb)
 148 {
 149         int err;
 150         write_lock_irq(&profile_lock);
 151         err = notifier_chain_register(&profile_listeners, nb);
 152         write_unlock_irq(&profile_lock);
 153         return err;
 154 }
 155
 156
 157 int unregister_profile_notifier(struct notifier_block * nb)
 158 {
 159         int err;
 160         write_lock_irq(&profile_lock);
 161         err = notifier_chain_unregister(&profile_listeners, nb);
 162         write_unlock_irq(&profile_lock);
 163         return err;
 164 }
 165
 166
 167 void profile_hook(struct pt_regs * regs)
 168 {
 169         read_lock(&profile_lock);
 170         notifier_call_chain(&profile_listeners, 0, regs);
 171         read_unlock(&profile_lock);
 172 }
 173
 174 EXPORT_SYMBOL_GPL(register_profile_notifier);
 175 EXPORT_SYMBOL_GPL(unregister_profile_notifier);
 176 EXPORT_SYMBOL_GPL(task_handoff_register);
 177 EXPORT_SYMBOL_GPL(task_handoff_unregister);
 178
 179 #endif /* CONFIG_PROFILING */
 180
 181 EXPORT_SYMBOL_GPL(profile_event_register);
 182 EXPORT_SYMBOL_GPL(profile_event_unregister);
 183
 184 void profile_hit(int type, void *__pc)
 185 {
 186         unsigned long pc;
 187
 188         if (prof_on != type || !prof_buffer)
 189                 return;
 190         pc = ((unsigned long)__pc - (unsigned long)_stext) >> prof_shift;
 191         atomic_inc(&prof_buffer[min(pc, prof_len - 1)]);
 192 }
 193
 194 void profile_tick(int type, struct pt_regs *regs)
 195 {
 196         if (type == CPU_PROFILING)
 197                 profile_hook(regs);
 198         if (!user_mode(regs) && cpu_isset(smp_processor_id(), prof_cpu_mask))
 199                 profile_hit(type, (void *)profile_pc(regs));
 200 }
 201
 202 #ifdef CONFIG_PROC_FS
 203 #include <linux/proc_fs.h>
 204 #include <asm/uaccess.h>
 205 #include <asm/ptrace.h>
 206
 207 static int prof_cpu_mask_read_proc (char *page, char **start, off_t off,
 208                         int count, int *eof, void *data)
 209 {
 210         int len = cpumask_scnprintf(page, count, *(cpumask_t *)data);
 211         if (count - len < 2)
 212                 return -EINVAL;
 213         len += sprintf(page + len, "\n");
 214         return len;
 215 }
 216
 217 static int prof_cpu_mask_write_proc (struct file *file, const char __user *buffer,
 218                                         unsigned long count, void *data)
 219 {
 220         cpumask_t *mask = (cpumask_t *)data;
 221         unsigned long full_count = count, err;
 222         cpumask_t new_value;
 223
 224         err = cpumask_parse(buffer, count, new_value);
 225         if (err)
 226                 return err;
 227
 228         *mask = new_value;
 229         return full_count;
 230 }
 231
 232 void create_prof_cpu_mask(struct proc_dir_entry *root_irq_dir)
 233 {
 234         struct proc_dir_entry *entry;
 235
 236         /* create /proc/irq/prof_cpu_mask */
 237         if (!(entry = create_proc_entry("prof_cpu_mask", 0600, root_irq_dir)))
 238                 return;
 239         entry->nlink = 1;
 240         entry->data = (void *)&prof_cpu_mask;
 241         entry->read_proc = prof_cpu_mask_read_proc;
 242         entry->write_proc = prof_cpu_mask_write_proc;
 243 }
 244
 245 /*
 246  * This function accesses profiling information. The returned data is
 247  * binary: the sampling step and the actual contents of the profile
 248  * buffer. Use of the program readprofile is recommended in order to
 249  * get meaningful info out of these data.
 250  */
 251 static ssize_t
 252 read_profile(struct file *file, char __user *buf, size_t count, loff_t *ppos)
 253 {
 254         unsigned long p = *ppos;
 255         ssize_t read;
 256         char * pnt;
 257         unsigned int sample_step = 1 << prof_shift;
 258
 259         if (p >= (prof_len+1)*sizeof(unsigned int))
 260                 return 0;
 261         if (count > (prof_len+1)*sizeof(unsigned int) - p)
 262                 count = (prof_len+1)*sizeof(unsigned int) - p;
 263         read = 0;
 264
 265         while (p < sizeof(unsigned int) && count > 0) {
 266                 put_user(*((char *)(&sample_step)+p),buf);
 267                 buf++; p++; count--; read++;
 268         }
 269         pnt = (char *)prof_buffer + p - sizeof(atomic_t);
 270         if (copy_to_user(buf,(void *)pnt,count))
 271                 return -EFAULT;
 272         read += count;
 273         *ppos += read;
 274         return read;
 275 }
 276
 277 /*
 278  * Writing to /proc/profile resets the counters
 279  *
 280  * Writing a 'profiling multiplier' value into it also re-sets the profiling
 281  * interrupt frequency, on architectures that support this.
 282  */
 283 static ssize_t write_profile(struct file *file, const char __user *buf,
 284                              size_t count, loff_t *ppos)
 285 {
 286 #ifdef CONFIG_SMP
 287         extern int setup_profiling_timer (unsigned int multiplier);
 288
 289         if (count == sizeof(int)) {
 290                 unsigned int multiplier;
 291
 292                 if (copy_from_user(&multiplier, buf, sizeof(int)))
 293                         return -EFAULT;
 294
 295                 if (setup_profiling_timer(multiplier))
 296                         return -EINVAL;
 297         }
 298 #endif
 299
 300         memset(prof_buffer, 0, prof_len * sizeof(atomic_t));
 301         return count;
 302 }
 303
 304 static struct file_operations proc_profile_operations = {
 305         .read           = read_profile,
 306         .write          = write_profile,
 307 };
 308
 309 static int __init create_proc_profile(void)
 310 {
 311         struct proc_dir_entry *entry;
 312
 313         if (!prof_on)
 314                 return 0;
 315         if (!(entry = create_proc_entry("profile", S_IWUSR | S_IRUGO, NULL)))
 316                 return 0;
 317         entry->proc_fops = &proc_profile_operations;
 318         entry->size = (1+prof_len) * sizeof(atomic_t);
 319         return 0;
 320 }
 321 module_init(create_proc_profile);
 322 #endif /* CONFIG_PROC_FS */