linux/arch/cris/kernel/profile.c
Arjan van de Ven 5dfe4c964a [PATCH] mark struct file_operations const 2
Many struct file_operations in the kernel can be "const".  Marking them const
moves these to the .rodata section, which avoids false sharing with potential
dirty data.  In addition it'll catch accidental writes at compile time to
these shared resources.

[akpm@osdl.org: sparc64 fix]
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-12 09:48:44 -08:00

73 lines
1.8 KiB
C

#include <linux/init.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/proc_fs.h>
#include <linux/types.h>
#include <asm/ptrace.h>
#include <asm/uaccess.h>
#define SAMPLE_BUFFER_SIZE 8192
static char* sample_buffer;
static char* sample_buffer_pos;
static int prof_running = 0;
void
cris_profile_sample(struct pt_regs* regs)
{
if (!prof_running)
return;
if (user_mode(regs))
*(unsigned int*)sample_buffer_pos = current->pid;
else
*(unsigned int*)sample_buffer_pos = 0;
*(unsigned int*)(sample_buffer_pos + 4) = instruction_pointer(regs);
sample_buffer_pos += 8;
if (sample_buffer_pos == sample_buffer + SAMPLE_BUFFER_SIZE)
sample_buffer_pos = sample_buffer;
}
static ssize_t
read_cris_profile(struct file *file, char __user *buf, size_t count, loff_t *ppos)
{
unsigned long p = *ppos;
if (p > SAMPLE_BUFFER_SIZE)
return 0;
if (p + count > SAMPLE_BUFFER_SIZE)
count = SAMPLE_BUFFER_SIZE - p;
if (copy_to_user(buf, sample_buffer + p,count))
return -EFAULT;
memset(sample_buffer + p, 0, count);
*ppos += count;
return count;
}
static ssize_t
write_cris_profile(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
sample_buffer_pos = sample_buffer;
memset(sample_buffer, 0, SAMPLE_BUFFER_SIZE);
}
static const struct file_operations cris_proc_profile_operations = {
.read = read_cris_profile,
.write = write_cris_profile,
};
static int
__init init_cris_profile(void)
{
struct proc_dir_entry *entry;
sample_buffer = kmalloc(SAMPLE_BUFFER_SIZE, GFP_KERNEL);
sample_buffer_pos = sample_buffer;
entry = create_proc_entry("system_profile", S_IWUSR | S_IRUGO, NULL);
if (entry) {
entry->proc_fops = &cris_proc_profile_operations;
entry->size = SAMPLE_BUFFER_SIZE;
}
prof_running = 1;
return 0;
}
__initcall(init_cris_profile);