arch/cris/kernel/profile.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <linux/init.h>
   3 #include <linux/errno.h>
   4 #include <linux/kernel.h>
   5 #include <linux/proc_fs.h>
   6 #include <linux/slab.h>
   7 #include <linux/types.h>
   8 #include <asm/ptrace.h>
   9 #include <linux/uaccess.h>
  10
  11 #define SAMPLE_BUFFER_SIZE 8192
  12
  13 static char *sample_buffer;
  14 static char *sample_buffer_pos;
  15 static int prof_running = 0;
  16
  17 void cris_profile_sample(struct pt_regs *regs)
  18 {
  19         if (!prof_running)
  20                 return;
  21
  22         if (user_mode(regs))
  23                 *(unsigned int*)sample_buffer_pos = current->pid;
  24         else
  25                 *(unsigned int*)sample_buffer_pos = 0;
  26
  27         *(unsigned int *)(sample_buffer_pos + 4) = instruction_pointer(regs);
  28         sample_buffer_pos += 8;
  29
  30         if (sample_buffer_pos == sample_buffer + SAMPLE_BUFFER_SIZE)
  31                 sample_buffer_pos = sample_buffer;
  32 }
  33
  34 static ssize_t
  35 read_cris_profile(struct file *file, char __user *buf,
  36                   size_t count, loff_t *ppos)
  37 {
  38         unsigned long p = *ppos;
  39         ssize_t ret;
  40
  41         ret = simple_read_from_buffer(buf, count, ppos, sample_buffer,
  42                                                 SAMPLE_BUFFER_SIZE);
  43         if (ret < 0)
  44                 return ret;
  45
  46         memset(sample_buffer + p, 0, ret);
  47
  48         return ret;
  49 }
  50
  51 static ssize_t
  52 write_cris_profile(struct file *file, const char __user *buf,
  53                    size_t count, loff_t *ppos)
  54 {
  55         sample_buffer_pos = sample_buffer;
  56         memset(sample_buffer, 0, SAMPLE_BUFFER_SIZE);
  57         return count < SAMPLE_BUFFER_SIZE ? count : SAMPLE_BUFFER_SIZE;
  58 }
  59
  60 static const struct file_operations cris_proc_profile_operations = {
  61         .read           = read_cris_profile,
  62         .write          = write_cris_profile,
  63         .llseek         = default_llseek,
  64 };
  65
  66 static int __init init_cris_profile(void)
  67 {
  68         struct proc_dir_entry *entry;
  69
  70         sample_buffer = kmalloc(SAMPLE_BUFFER_SIZE, GFP_KERNEL);
  71         if (!sample_buffer) {
  72                 return -ENOMEM;
  73         }
  74
  75         sample_buffer_pos = sample_buffer;
  76
  77         entry = proc_create("system_profile", S_IWUSR | S_IRUGO, NULL,
  78                             &cris_proc_profile_operations);
  79         if (entry) {
  80                 proc_set_size(entry, SAMPLE_BUFFER_SIZE);
  81         }
  82         prof_running = 1;
  83
  84         return 0;
  85 }
  86 __initcall(init_cris_profile);
  87