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b66f868494
Using write_support=1 with the ec_sys module changes the mode of the "io" debugfs file to 0600. This will cause any attempts to access it under a kernel in lockdown mode to return -EPERM, which makes the entire ec_sys module unusable. Use the special module_param_hw() macro for module parameters which may not be used while in lockdown mode, to avoid this. Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
144 lines
3.2 KiB
C
144 lines
3.2 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* ec_sys.c
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*
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* Copyright (C) 2010 SUSE Products GmbH/Novell
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* Author:
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* Thomas Renninger <trenn@suse.de>
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*/
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#include <linux/kernel.h>
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#include <linux/acpi.h>
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#include <linux/debugfs.h>
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#include <linux/module.h>
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#include <linux/uaccess.h>
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#include "internal.h"
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MODULE_AUTHOR("Thomas Renninger <trenn@suse.de>");
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MODULE_DESCRIPTION("ACPI EC sysfs access driver");
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MODULE_LICENSE("GPL");
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static bool write_support;
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module_param_hw(write_support, bool, other, 0644);
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MODULE_PARM_DESC(write_support, "Dangerous, reboot and removal of battery may "
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"be needed.");
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#define EC_SPACE_SIZE 256
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static struct dentry *acpi_ec_debugfs_dir;
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static ssize_t acpi_ec_read_io(struct file *f, char __user *buf,
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size_t count, loff_t *off)
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{
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/* Use this if support reading/writing multiple ECs exists in ec.c:
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* struct acpi_ec *ec = ((struct seq_file *)f->private_data)->private;
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*/
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unsigned int size = EC_SPACE_SIZE;
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loff_t init_off = *off;
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int err = 0;
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if (*off >= size)
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return 0;
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if (*off + count >= size) {
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size -= *off;
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count = size;
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} else
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size = count;
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while (size) {
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u8 byte_read;
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err = ec_read(*off, &byte_read);
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if (err)
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return err;
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if (put_user(byte_read, buf + *off - init_off)) {
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if (*off - init_off)
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return *off - init_off; /* partial read */
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return -EFAULT;
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}
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*off += 1;
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size--;
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}
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return count;
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}
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static ssize_t acpi_ec_write_io(struct file *f, const char __user *buf,
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size_t count, loff_t *off)
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{
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/* Use this if support reading/writing multiple ECs exists in ec.c:
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* struct acpi_ec *ec = ((struct seq_file *)f->private_data)->private;
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*/
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unsigned int size = count;
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loff_t init_off = *off;
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int err = 0;
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if (!write_support)
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return -EINVAL;
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if (*off >= EC_SPACE_SIZE)
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return 0;
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if (*off + count >= EC_SPACE_SIZE) {
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size = EC_SPACE_SIZE - *off;
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count = size;
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}
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while (size) {
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u8 byte_write;
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if (get_user(byte_write, buf + *off - init_off)) {
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if (*off - init_off)
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return *off - init_off; /* partial write */
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return -EFAULT;
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}
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err = ec_write(*off, byte_write);
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if (err)
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return err;
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*off += 1;
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size--;
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}
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return count;
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}
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static const struct file_operations acpi_ec_io_ops = {
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.owner = THIS_MODULE,
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.open = simple_open,
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.read = acpi_ec_read_io,
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.write = acpi_ec_write_io,
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.llseek = default_llseek,
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};
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static void acpi_ec_add_debugfs(struct acpi_ec *ec, unsigned int ec_device_count)
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{
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struct dentry *dev_dir;
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char name[64];
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umode_t mode = 0400;
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if (ec_device_count == 0)
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acpi_ec_debugfs_dir = debugfs_create_dir("ec", NULL);
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sprintf(name, "ec%u", ec_device_count);
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dev_dir = debugfs_create_dir(name, acpi_ec_debugfs_dir);
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debugfs_create_x32("gpe", 0444, dev_dir, &first_ec->gpe);
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debugfs_create_bool("use_global_lock", 0444, dev_dir,
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&first_ec->global_lock);
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if (write_support)
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mode = 0600;
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debugfs_create_file("io", mode, dev_dir, ec, &acpi_ec_io_ops);
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}
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static int __init acpi_ec_sys_init(void)
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{
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if (first_ec)
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acpi_ec_add_debugfs(first_ec, 0);
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return 0;
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}
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static void __exit acpi_ec_sys_exit(void)
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{
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debugfs_remove_recursive(acpi_ec_debugfs_dir);
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}
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module_init(acpi_ec_sys_init);
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module_exit(acpi_ec_sys_exit);
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