oprofile_files.c

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#include <linux/fs.h>
#include <linux/oprofile.h>
#include <linux/jiffies.h>

#include "event_buffer.h"
#include "oprofile_stats.h"
#include "oprof.h"

#define BUFFER_SIZE_DEFAULT     131072
#define CPU_BUFFER_SIZE_DEFAULT     8192
#define BUFFER_WATERSHED_DEFAULT    32768   /* FIXME: tune */
#define TIME_SLICE_DEFAULT      1

unsigned long oprofile_buffer_size;
unsigned long oprofile_cpu_buffer_size;
unsigned long oprofile_buffer_watershed;
unsigned long oprofile_time_slice;

#ifdef CONFIG_OPROFILE_EVENT_MULTIPLEX

static ssize_t timeout_read(struct file *file, char __user *buf,
        size_t count, loff_t *offset)
{
    return oprofilefs_ulong_to_user(jiffies_to_msecs(oprofile_time_slice),
                    buf, count, offset);
}


static ssize_t timeout_write(struct file *file, char const __user *buf,
        size_t count, loff_t *offset)
{
    unsigned long val;
    int retval;

    if (*offset)
        return -EINVAL;

    retval = oprofilefs_ulong_from_user(&val, buf, count);
    if (retval <= 0)
        return retval;

    retval = oprofile_set_timeout(val);

    if (retval)
        return retval;
    return count;
}


static const struct file_operations timeout_fops = {
    .read       = timeout_read,
    .write      = timeout_write,
    .llseek     = default_llseek,
};

#endif


static ssize_t depth_read(struct file *file, char __user *buf, size_t count, loff_t *offset)
{
    return oprofilefs_ulong_to_user(oprofile_backtrace_depth, buf, count,
                    offset);
}


static ssize_t depth_write(struct file *file, char const __user *buf, size_t count, loff_t *offset)
{
    unsigned long val;
    int retval;

    if (*offset)
        return -EINVAL;

    if (!oprofile_ops.backtrace)
        return -EINVAL;

    retval = oprofilefs_ulong_from_user(&val, buf, count);
    if (retval <= 0)
        return retval;

    retval = oprofile_set_ulong(&oprofile_backtrace_depth, val);
    if (retval)
        return retval;

    return count;
}


static const struct file_operations depth_fops = {
    .read       = depth_read,
    .write      = depth_write,
    .llseek     = default_llseek,
};


static ssize_t pointer_size_read(struct file *file, char __user *buf, size_t count, loff_t *offset)
{
    return oprofilefs_ulong_to_user(sizeof(void *), buf, count, offset);
}


static const struct file_operations pointer_size_fops = {
    .read       = pointer_size_read,
    .llseek     = default_llseek,
};


static ssize_t cpu_type_read(struct file *file, char __user *buf, size_t count, loff_t *offset)
{
    return oprofilefs_str_to_user(oprofile_ops.cpu_type, buf, count, offset);
}


static const struct file_operations cpu_type_fops = {
    .read       = cpu_type_read,
    .llseek     = default_llseek,
};


static ssize_t enable_read(struct file *file, char __user *buf, size_t count, loff_t *offset)
{
    return oprofilefs_ulong_to_user(oprofile_started, buf, count, offset);
}


static ssize_t enable_write(struct file *file, char const __user *buf, size_t count, loff_t *offset)
{
    unsigned long val;
    int retval;

    if (*offset)
        return -EINVAL;

    retval = oprofilefs_ulong_from_user(&val, buf, count);
    if (retval <= 0)
        return retval;

    retval = 0;
    if (val)
        retval = oprofile_start();
    else
        oprofile_stop();

    if (retval)
        return retval;
    return count;
}


static const struct file_operations enable_fops = {
    .read       = enable_read,
    .write      = enable_write,
    .llseek     = default_llseek,
};


static ssize_t dump_write(struct file *file, char const __user *buf, size_t count, loff_t *offset)
{
    wake_up_buffer_waiter();
    return count;
}


static const struct file_operations dump_fops = {
    .write      = dump_write,
    .llseek     = noop_llseek,
};

void oprofile_create_files(struct super_block *sb, struct dentry *root)
{
    /* reinitialize default values */
    oprofile_buffer_size =      BUFFER_SIZE_DEFAULT;
    oprofile_cpu_buffer_size =  CPU_BUFFER_SIZE_DEFAULT;
    oprofile_buffer_watershed = BUFFER_WATERSHED_DEFAULT;
    oprofile_time_slice =       msecs_to_jiffies(TIME_SLICE_DEFAULT);

    oprofilefs_create_file(sb, root, "enable", &enable_fops);
    oprofilefs_create_file_perm(sb, root, "dump", &dump_fops, 0666);
    oprofilefs_create_file(sb, root, "buffer", &event_buffer_fops);
    oprofilefs_create_ulong(sb, root, "buffer_size", &oprofile_buffer_size);
    oprofilefs_create_ulong(sb, root, "buffer_watershed", &oprofile_buffer_watershed);
    oprofilefs_create_ulong(sb, root, "cpu_buffer_size", &oprofile_cpu_buffer_size);
    oprofilefs_create_file(sb, root, "cpu_type", &cpu_type_fops);
    oprofilefs_create_file(sb, root, "backtrace_depth", &depth_fops);
    oprofilefs_create_file(sb, root, "pointer_size", &pointer_size_fops);
#ifdef CONFIG_OPROFILE_EVENT_MULTIPLEX
    oprofilefs_create_file(sb, root, "time_slice", &timeout_fops);
#endif
    oprofile_create_stats_files(sb, root);
    if (oprofile_ops.create_files)
        oprofile_ops.create_files(sb, root);
}