linux/arch/cris/kernel/profile.c
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   1#include <linux/init.h>
   2#include <linux/errno.h>
   3#include <linux/kernel.h>
   4#include <linux/proc_fs.h>
   5#include <linux/types.h>
   6#include <asm/ptrace.h>
   7#include <asm/uaccess.h>
   8
   9#define SAMPLE_BUFFER_SIZE 8192
  10
  11static char* sample_buffer;
  12static char* sample_buffer_pos;
  13static int prof_running = 0;
  14
  15void
  16cris_profile_sample(struct pt_regs* regs)
  17{
  18        if (!prof_running)
  19                return;
  20
  21        if (user_mode(regs))
  22                *(unsigned int*)sample_buffer_pos = current->pid;
  23        else
  24                *(unsigned int*)sample_buffer_pos = 0;
  25
  26        *(unsigned int*)(sample_buffer_pos + 4) = instruction_pointer(regs);
  27        sample_buffer_pos += 8;
  28
  29        if (sample_buffer_pos == sample_buffer + SAMPLE_BUFFER_SIZE)
  30                sample_buffer_pos = sample_buffer;
  31}
  32
  33static ssize_t
  34read_cris_profile(struct file *file, char __user *buf,
  35                  size_t count, loff_t *ppos)
  36{
  37        unsigned long p = *ppos;
  38        ssize_t ret;
  39
  40        ret = simple_read_from_buffer(buf, count, ppos, sample_buffer,
  41                                                SAMPLE_BUFFER_SIZE);
  42        if (ret < 0)
  43                return ret;
  44
  45        memset(sample_buffer + p, 0, ret);
  46
  47        return ret;
  48}
  49
  50static ssize_t
  51write_cris_profile(struct file *file, const char __user *buf,
  52                   size_t count, loff_t *ppos)
  53{
  54        sample_buffer_pos = sample_buffer;
  55        memset(sample_buffer, 0, SAMPLE_BUFFER_SIZE);
  56}
  57
  58static const struct file_operations cris_proc_profile_operations = {
  59        .read           = read_cris_profile,
  60        .write          = write_cris_profile,
  61};
  62
  63static int
  64__init init_cris_profile(void)
  65{
  66        struct proc_dir_entry *entry;
  67
  68        sample_buffer = kmalloc(SAMPLE_BUFFER_SIZE, GFP_KERNEL);
  69        if (!sample_buffer) {
  70                return -ENOMEM;
  71        }
  72
  73        sample_buffer_pos = sample_buffer;
  74
  75        entry = proc_create("system_profile", S_IWUSR | S_IRUGO, NULL,
  76                            &cris_proc_profile_operations);
  77        if (entry) {
  78                entry->size = SAMPLE_BUFFER_SIZE;
  79        }
  80        prof_running = 1;
  81
  82        return 0;
  83}
  84
  85__initcall(init_cris_profile);
  86