linux/drivers/acpi/fan.c
Ingo Molnar 48d3d8263c revert "ACPI: drivers/acpi: elide a non-zero test on a result that is never 0"
Revert commit 1192aeb957 ("ACPI:
drivers/acpi: elide a non-zero test on a result that is never 0")
because it turns out that thermal_cooling_device_register() does
actually return NULL if CONFIG_THERMAL is turned off (then the routine
turns into a dummy inline routine in the header files that returns NULL
unconditionally).

This was found with randconfig testing, causing a crash during bootup:

  initcall 0x78878534 ran for 13 msecs: acpi_button_init+0x0/0x51()
  Calling initcall 0x78878585: acpi_fan_init+0x0/0x2c()
  BUG: unable to handle kernel NULL pointer dereference at 00000000
  IP: [<782b8ad0>] acpi_fan_add+0x7d/0xfd
  *pde = 00000000
  Oops: 0000 [#1]
  Modules linked in:

  Pid: 1, comm: swapper Not tainted (2.6.25-rc7-sched-devel.git-x86-latest.git #14)
  EIP: 0060:[<782b8ad0>] EFLAGS: 00010246 CPU: 0
  EIP is at acpi_fan_add+0x7d/0xfd
  EAX: b787c718 EBX: b787c400 ECX: b782ceb4 EDX: 00000007
  ESI: 00000000 EDI: b787c6f4 EBP: b782cee0 ESP: b782cecc
   DS: 007b ES: 007b FS: 0000 GS: 0000 SS: 0068
  Process swapper (pid: 1, ti=b782c000 task=b7846000 task.ti=b782c000)
  Stack: b787c459 00000000 b787c400 78790888 b787c60c b782cef8 782b6fb8 ffffffda
         b787c60c 00000000 78790958 b782cf0c 783005d7 b787c60c 78790958 78790584
         b782cf1c 783007f6 b782cf28 00000000 b782cf40 782ffc4a 78790958 b794d558
  Call Trace:
   [<782b6fb8>] ? acpi_device_probe+0x3e/0xdb
   [<783005d7>] ? driver_probe_device+0x82/0xfc
   [<783007f6>] ? __driver_attach+0x3a/0x70
   [<782ffc4a>] ? bus_for_each_dev+0x3e/0x60
   [<7830048c>] ? driver_attach+0x14/0x16
   [<783007bc>] ? __driver_attach+0x0/0x70
   [<7830006a>] ? bus_add_driver+0x9d/0x1b0
   [<783008c3>] ? driver_register+0x47/0xa3
   [<7813db00>] ? timespec_to_ktime+0x9/0xc
   [<782b7331>] ? acpi_bus_register_driver+0x3a/0x3c
   [<78878592>] ? acpi_fan_init+0xd/0x2c
   [<78863656>] ? kernel_init+0xac/0x1f9
   [<788635aa>] ? kernel_init+0x0/0x1f9
   [<78114563>] ? kernel_thread_helper+0x7/0x10
   =======================
  Code: 6e 78 e8 57 44 e7 ff 58 e9 93 00 00 00 8b 55 f0 8d bb f4 02 00 00 80 4b 2d 10 8b 03 e8 87 cb ff ff 8d 83 18 03 00 00 80 63 2d ef <ff> 35 00 00 00 00 50 68 e8 9c 6e 78 e8 22 44 e7 ff b9 b6 9c 6e
  EIP: [<782b8ad0>] acpi_fan_add+0x7d/0xfd SS:ESP 0068:b782cecc
  ---[ end trace 778e504de7e3b1e3 ]---
  Kernel panic - not syncing: Attempted to kill init!

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-03-28 10:16:53 -07:00

374 lines
8.9 KiB
C

/*
* acpi_fan.c - ACPI Fan Driver ($Revision: 29 $)
*
* Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
* Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or (at
* your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <asm/uaccess.h>
#include <linux/thermal.h>
#include <acpi/acpi_bus.h>
#include <acpi/acpi_drivers.h>
#define ACPI_FAN_COMPONENT 0x00200000
#define ACPI_FAN_CLASS "fan"
#define ACPI_FAN_FILE_STATE "state"
#define _COMPONENT ACPI_FAN_COMPONENT
ACPI_MODULE_NAME("fan");
MODULE_AUTHOR("Paul Diefenbaugh");
MODULE_DESCRIPTION("ACPI Fan Driver");
MODULE_LICENSE("GPL");
static int acpi_fan_add(struct acpi_device *device);
static int acpi_fan_remove(struct acpi_device *device, int type);
static int acpi_fan_suspend(struct acpi_device *device, pm_message_t state);
static int acpi_fan_resume(struct acpi_device *device);
static const struct acpi_device_id fan_device_ids[] = {
{"PNP0C0B", 0},
{"", 0},
};
MODULE_DEVICE_TABLE(acpi, fan_device_ids);
static struct acpi_driver acpi_fan_driver = {
.name = "fan",
.class = ACPI_FAN_CLASS,
.ids = fan_device_ids,
.ops = {
.add = acpi_fan_add,
.remove = acpi_fan_remove,
.suspend = acpi_fan_suspend,
.resume = acpi_fan_resume,
},
};
/* thermal cooling device callbacks */
static int fan_get_max_state(struct thermal_cooling_device *cdev, char *buf)
{
/* ACPI fan device only support two states: ON/OFF */
return sprintf(buf, "1\n");
}
static int fan_get_cur_state(struct thermal_cooling_device *cdev, char *buf)
{
struct acpi_device *device = cdev->devdata;
int state;
int result;
if (!device)
return -EINVAL;
result = acpi_bus_get_power(device->handle, &state);
if (result)
return result;
return sprintf(buf, "%s\n", state == ACPI_STATE_D3 ? "0" :
(state == ACPI_STATE_D0 ? "1" : "unknown"));
}
static int
fan_set_cur_state(struct thermal_cooling_device *cdev, unsigned int state)
{
struct acpi_device *device = cdev->devdata;
int result;
if (!device || (state != 0 && state != 1))
return -EINVAL;
result = acpi_bus_set_power(device->handle,
state ? ACPI_STATE_D0 : ACPI_STATE_D3);
return result;
}
static struct thermal_cooling_device_ops fan_cooling_ops = {
.get_max_state = fan_get_max_state,
.get_cur_state = fan_get_cur_state,
.set_cur_state = fan_set_cur_state,
};
/* --------------------------------------------------------------------------
FS Interface (/proc)
-------------------------------------------------------------------------- */
#ifdef CONFIG_ACPI_PROCFS
static struct proc_dir_entry *acpi_fan_dir;
static int acpi_fan_read_state(struct seq_file *seq, void *offset)
{
struct acpi_device *device = seq->private;
int state = 0;
if (device) {
if (acpi_bus_get_power(device->handle, &state))
seq_printf(seq, "status: ERROR\n");
else
seq_printf(seq, "status: %s\n",
!state ? "on" : "off");
}
return 0;
}
static int acpi_fan_state_open_fs(struct inode *inode, struct file *file)
{
return single_open(file, acpi_fan_read_state, PDE(inode)->data);
}
static ssize_t
acpi_fan_write_state(struct file *file, const char __user * buffer,
size_t count, loff_t * ppos)
{
int result = 0;
struct seq_file *m = file->private_data;
struct acpi_device *device = m->private;
char state_string[12] = { '\0' };
if (count > sizeof(state_string) - 1)
return -EINVAL;
if (copy_from_user(state_string, buffer, count))
return -EFAULT;
state_string[count] = '\0';
result = acpi_bus_set_power(device->handle,
simple_strtoul(state_string, NULL, 0));
if (result)
return result;
return count;
}
static const struct file_operations acpi_fan_state_ops = {
.open = acpi_fan_state_open_fs,
.read = seq_read,
.write = acpi_fan_write_state,
.llseek = seq_lseek,
.release = single_release,
.owner = THIS_MODULE,
};
static int acpi_fan_add_fs(struct acpi_device *device)
{
struct proc_dir_entry *entry = NULL;
if (!device)
return -EINVAL;
if (!acpi_device_dir(device)) {
acpi_device_dir(device) = proc_mkdir(acpi_device_bid(device),
acpi_fan_dir);
if (!acpi_device_dir(device))
return -ENODEV;
acpi_device_dir(device)->owner = THIS_MODULE;
}
/* 'status' [R/W] */
entry = create_proc_entry(ACPI_FAN_FILE_STATE,
S_IFREG | S_IRUGO | S_IWUSR,
acpi_device_dir(device));
if (!entry)
return -ENODEV;
else {
entry->proc_fops = &acpi_fan_state_ops;
entry->data = device;
entry->owner = THIS_MODULE;
}
return 0;
}
static int acpi_fan_remove_fs(struct acpi_device *device)
{
if (acpi_device_dir(device)) {
remove_proc_entry(ACPI_FAN_FILE_STATE, acpi_device_dir(device));
remove_proc_entry(acpi_device_bid(device), acpi_fan_dir);
acpi_device_dir(device) = NULL;
}
return 0;
}
#else
static int acpi_fan_add_fs(struct acpi_device *device)
{
return 0;
}
static int acpi_fan_remove_fs(struct acpi_device *device)
{
return 0;
}
#endif
/* --------------------------------------------------------------------------
Driver Interface
-------------------------------------------------------------------------- */
static int acpi_fan_add(struct acpi_device *device)
{
int result = 0;
int state = 0;
struct thermal_cooling_device *cdev;
if (!device)
return -EINVAL;
strcpy(acpi_device_name(device), "Fan");
strcpy(acpi_device_class(device), ACPI_FAN_CLASS);
result = acpi_bus_get_power(device->handle, &state);
if (result) {
printk(KERN_ERR PREFIX "Reading power state\n");
goto end;
}
device->flags.force_power_state = 1;
acpi_bus_set_power(device->handle, state);
device->flags.force_power_state = 0;
cdev = thermal_cooling_device_register("Fan", device,
&fan_cooling_ops);
if (IS_ERR(cdev)) {
result = PTR_ERR(cdev);
goto end;
}
if (cdev) {
printk(KERN_INFO PREFIX
"%s is registered as cooling_device%d\n",
device->dev.bus_id, cdev->id);
acpi_driver_data(device) = cdev;
result = sysfs_create_link(&device->dev.kobj,
&cdev->device.kobj,
"thermal_cooling");
if (result)
return result;
result = sysfs_create_link(&cdev->device.kobj,
&device->dev.kobj,
"device");
if (result)
return result;
}
result = acpi_fan_add_fs(device);
if (result)
goto end;
printk(KERN_INFO PREFIX "%s [%s] (%s)\n",
acpi_device_name(device), acpi_device_bid(device),
!device->power.state ? "on" : "off");
end:
return result;
}
static int acpi_fan_remove(struct acpi_device *device, int type)
{
struct thermal_cooling_device *cdev = acpi_driver_data(device);
if (!device || !cdev)
return -EINVAL;
acpi_fan_remove_fs(device);
sysfs_remove_link(&device->dev.kobj, "thermal_cooling");
sysfs_remove_link(&cdev->device.kobj, "device");
thermal_cooling_device_unregister(cdev);
return 0;
}
static int acpi_fan_suspend(struct acpi_device *device, pm_message_t state)
{
if (!device)
return -EINVAL;
acpi_bus_set_power(device->handle, ACPI_STATE_D0);
return AE_OK;
}
static int acpi_fan_resume(struct acpi_device *device)
{
int result = 0;
int power_state = 0;
if (!device)
return -EINVAL;
result = acpi_bus_get_power(device->handle, &power_state);
if (result) {
ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
"Error reading fan power state\n"));
return result;
}
device->flags.force_power_state = 1;
acpi_bus_set_power(device->handle, power_state);
device->flags.force_power_state = 0;
return result;
}
static int __init acpi_fan_init(void)
{
int result = 0;
#ifdef CONFIG_ACPI_PROCFS
acpi_fan_dir = proc_mkdir(ACPI_FAN_CLASS, acpi_root_dir);
if (!acpi_fan_dir)
return -ENODEV;
acpi_fan_dir->owner = THIS_MODULE;
#endif
result = acpi_bus_register_driver(&acpi_fan_driver);
if (result < 0) {
remove_proc_entry(ACPI_FAN_CLASS, acpi_root_dir);
return -ENODEV;
}
return 0;
}
static void __exit acpi_fan_exit(void)
{
acpi_bus_unregister_driver(&acpi_fan_driver);
remove_proc_entry(ACPI_FAN_CLASS, acpi_root_dir);
return;
}
module_init(acpi_fan_init);
module_exit(acpi_fan_exit);