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/*
* debugfs.c - ACPI debugfs interface to userspace.
*/
#include <linux/init.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/uaccess.h>
#include <linux/debugfs.h>
#include <acpi/acpi_drivers.h>
#define _COMPONENT ACPI_SYSTEM_COMPONENT
ACPI_MODULE_NAME("debugfs");
/* /sys/kernel/debug/acpi/custom_method */
static ssize_t cm_write(struct file *file, const char __user * user_buf,
size_t count, loff_t *ppos)
{
static char *buf;
static int uncopied_bytes;
struct acpi_table_header table;
acpi_status status;
if (!(*ppos)) {
/* parse the table header to get the table length */
if (count <= sizeof(struct acpi_table_header))
return -EINVAL;
if (copy_from_user(&table, user_buf,
sizeof(struct acpi_table_header)))
return -EFAULT;
uncopied_bytes = table.length;
buf = kzalloc(uncopied_bytes, GFP_KERNEL);
if (!buf)
return -ENOMEM;
}
if (uncopied_bytes < count) {
kfree(buf);
return -EINVAL;
}
if (copy_from_user(buf + (*ppos), user_buf, count)) {
kfree(buf);
return -EFAULT;
}
uncopied_bytes -= count;
*ppos += count;
if (!uncopied_bytes) {
status = acpi_install_method(buf);
kfree(buf);
if (ACPI_FAILURE(status))
return -EINVAL;
add_taint(TAINT_OVERRIDDEN_ACPI_TABLE);
}
return count;
}
static const struct file_operations cm_fops = {
.write = cm_write,
};
int __init acpi_debugfs_init(void)
{
struct dentry *acpi_dir, *cm_dentry;
acpi_dir = debugfs_create_dir("acpi", NULL);
if (!acpi_dir)
goto err;
cm_dentry = debugfs_create_file("custom_method", S_IWUGO,
acpi_dir, NULL, &cm_fops);
if (!cm_dentry)
goto err;
return 0;
err:
if (acpi_dir)
debugfs_remove(acpi_dir);
return -EINVAL;
}
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