linux/drivers/acpi/ac.c
Krzysztof Kozlowski 297d716f62 power_supply: Change ownership from driver to core
Change the ownership of power_supply structure from each driver
implementing the class to the power supply core.

The patch changes power_supply_register() function thus all drivers
implementing power supply class are adjusted.

Each driver provides the implementation of power supply. However it
should not be the owner of power supply class instance because it is
exposed by core to other subsystems with power_supply_get_by_name().
These other subsystems have no knowledge when the driver will unregister
the power supply. This leads to several issues when driver is unbound -
mostly because user of power supply accesses freed memory.

Instead let the core own the instance of struct 'power_supply'.  Other
users of this power supply will still access valid memory because it
will be freed when device reference count reaches 0. Currently this
means "it will leak" but power_supply_put() call in next patches will
solve it.

This solves invalid memory references in following race condition
scenario:

Thread 1: charger manager
Thread 2: power supply driver, used by charger manager

THREAD 1 (charger manager)         THREAD 2 (power supply driver)
==========================         ==============================
psy = power_supply_get_by_name()
                                   Driver unbind, .remove
                                     power_supply_unregister()
                                     Device fully removed
psy->get_property()

The 'get_property' call is executed in invalid context because the driver was
unbound and struct 'power_supply' memory was freed.

This could be observed easily with charger manager driver (here compiled
with max17040 fuel gauge):

$ cat /sys/devices/virtual/power_supply/cm-battery/capacity &
$ echo "1-0036" > /sys/bus/i2c/drivers/max17040/unbind
[   55.725123] Unable to handle kernel NULL pointer dereference at virtual address 00000000
[   55.732584] pgd = d98d4000
[   55.734060] [00000000] *pgd=5afa2831, *pte=00000000, *ppte=00000000
[   55.740318] Internal error: Oops: 80000007 [#1] PREEMPT SMP ARM
[   55.746210] Modules linked in:
[   55.749259] CPU: 1 PID: 2936 Comm: cat Tainted: G        W       3.19.0-rc1-next-20141226-00048-gf79f475f3c44-dirty #1496
[   55.760190] Hardware name: SAMSUNG EXYNOS (Flattened Device Tree)
[   55.766270] task: d9b76f00 ti: daf54000 task.ti: daf54000
[   55.771647] PC is at 0x0
[   55.774182] LR is at charger_get_property+0x2f4/0x36c
[   55.779201] pc : [<00000000>]    lr : [<c034b0b4>]    psr: 60000013
[   55.779201] sp : daf55e90  ip : 00000003  fp : 00000000
[   55.790657] r10: 00000000  r9 : c06e2878  r8 : d9b26c68
[   55.795865] r7 : dad81610  r6 : daec7410  r5 : daf55ebc  r4 : 00000000
[   55.802367] r3 : 00000000  r2 : daf55ebc  r1 : 0000002a  r0 : d9b26c68
[   55.808879] Flags: nZCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment user
[   55.815994] Control: 10c5387d  Table: 598d406a  DAC: 00000015
[   55.821723] Process cat (pid: 2936, stack limit = 0xdaf54210)
[   55.827451] Stack: (0xdaf55e90 to 0xdaf56000)
[   55.831795] 5e80:                                     60000013 c01459c4 0000002a c06f8ef8
[   55.839956] 5ea0: db651000 c06f8ef8 daebac00 c04cb668 daebac08 c0346864 00000000 c01459c4
[   55.848115] 5ec0: d99eaa80 c06f8ef8 00000fff 00001000 db651000 c027f25c c027f240 d99eaa80
[   55.856274] 5ee0: d9a06c00 c0146218 daf55f18 00001000 d99eaa80 db4c18c0 00000001 00000001
[   55.864468] 5f00: daf55f80 c0144c78 c0144c54 c0107f90 00015000 d99eaab0 00000000 00000000
[   55.872603] 5f20: 000051c7 00000000 db4c18c0 c04a9370 00015000 00001000 daf55f80 00001000
[   55.880763] 5f40: daf54000 00015000 00000000 c00e53dc db4c18c0 c00e548c 0000000d 00008124
[   55.888937] 5f60: 00000001 00000000 00000000 db4c18c0 db4c18c0 00001000 00015000 c00e5550
[   55.897099] 5f80: 00000000 00000000 00001000 00001000 00015000 00000003 00000003 c000f364
[   55.905239] 5fa0: 00000000 c000f1a0 00001000 00015000 00000003 00015000 00001000 0001333c
[   55.913399] 5fc0: 00001000 00015000 00000003 00000003 00000002 00000000 00000000 00000000
[   55.921560] 5fe0: 7fffe000 be999850 0000a225 b6f3c19c 60000010 00000003 00000000 00000000
[   55.929744] [<c034b0b4>] (charger_get_property) from [<c0346864>] (power_supply_show_property+0x48/0x20c)
[   55.939286] [<c0346864>] (power_supply_show_property) from [<c027f25c>] (dev_attr_show+0x1c/0x48)
[   55.948130] [<c027f25c>] (dev_attr_show) from [<c0146218>] (sysfs_kf_seq_show+0x84/0x104)
[   55.956298] [<c0146218>] (sysfs_kf_seq_show) from [<c0144c78>] (kernfs_seq_show+0x24/0x28)
[   55.964536] [<c0144c78>] (kernfs_seq_show) from [<c0107f90>] (seq_read+0x1b0/0x484)
[   55.972172] [<c0107f90>] (seq_read) from [<c00e53dc>] (__vfs_read+0x18/0x4c)
[   55.979188] [<c00e53dc>] (__vfs_read) from [<c00e548c>] (vfs_read+0x7c/0x100)
[   55.986304] [<c00e548c>] (vfs_read) from [<c00e5550>] (SyS_read+0x40/0x8c)
[   55.993164] [<c00e5550>] (SyS_read) from [<c000f1a0>] (ret_fast_syscall+0x0/0x48)
[   56.000626] Code: bad PC value
[   56.011652] ---[ end trace 7b64343fbdae8ef1 ]---

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Reviewed-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

[for the nvec part]
Reviewed-by: Marc Dietrich <marvin24@gmx.de>

[for compal-laptop.c]
Acked-by: Darren Hart <dvhart@linux.intel.com>

[for the mfd part]
Acked-by: Lee Jones <lee.jones@linaro.org>

[for the hid part]
Acked-by: Jiri Kosina <jkosina@suse.cz>

[for the acpi part]
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Signed-off-by: Sebastian Reichel <sre@kernel.org>
2015-03-13 23:15:51 +01:00

463 lines
11 KiB
C

/*
* acpi_ac.c - ACPI AC Adapter Driver ($Revision: 27 $)
*
* 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/slab.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/dmi.h>
#include <linux/delay.h>
#ifdef CONFIG_ACPI_PROCFS_POWER
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#endif
#include <linux/platform_device.h>
#include <linux/power_supply.h>
#include <linux/acpi.h>
#include "battery.h"
#define PREFIX "ACPI: "
#define ACPI_AC_CLASS "ac_adapter"
#define ACPI_AC_DEVICE_NAME "AC Adapter"
#define ACPI_AC_FILE_STATE "state"
#define ACPI_AC_NOTIFY_STATUS 0x80
#define ACPI_AC_STATUS_OFFLINE 0x00
#define ACPI_AC_STATUS_ONLINE 0x01
#define ACPI_AC_STATUS_UNKNOWN 0xFF
#define _COMPONENT ACPI_AC_COMPONENT
ACPI_MODULE_NAME("ac");
MODULE_AUTHOR("Paul Diefenbaugh");
MODULE_DESCRIPTION("ACPI AC Adapter Driver");
MODULE_LICENSE("GPL");
static int acpi_ac_add(struct acpi_device *device);
static int acpi_ac_remove(struct acpi_device *device);
static void acpi_ac_notify(struct acpi_device *device, u32 event);
static const struct acpi_device_id ac_device_ids[] = {
{"ACPI0003", 0},
{"", 0},
};
MODULE_DEVICE_TABLE(acpi, ac_device_ids);
#ifdef CONFIG_PM_SLEEP
static int acpi_ac_resume(struct device *dev);
#endif
static SIMPLE_DEV_PM_OPS(acpi_ac_pm, NULL, acpi_ac_resume);
#ifdef CONFIG_ACPI_PROCFS_POWER
extern struct proc_dir_entry *acpi_lock_ac_dir(void);
extern void *acpi_unlock_ac_dir(struct proc_dir_entry *acpi_ac_dir);
static int acpi_ac_open_fs(struct inode *inode, struct file *file);
#endif
static int ac_sleep_before_get_state_ms;
static struct acpi_driver acpi_ac_driver = {
.name = "ac",
.class = ACPI_AC_CLASS,
.ids = ac_device_ids,
.flags = ACPI_DRIVER_ALL_NOTIFY_EVENTS,
.ops = {
.add = acpi_ac_add,
.remove = acpi_ac_remove,
.notify = acpi_ac_notify,
},
.drv.pm = &acpi_ac_pm,
};
struct acpi_ac {
struct power_supply *charger;
struct power_supply_desc charger_desc;
struct acpi_device * device;
unsigned long long state;
struct notifier_block battery_nb;
};
#define to_acpi_ac(x) power_supply_get_drvdata(x)
#ifdef CONFIG_ACPI_PROCFS_POWER
static const struct file_operations acpi_ac_fops = {
.owner = THIS_MODULE,
.open = acpi_ac_open_fs,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
};
#endif
/* --------------------------------------------------------------------------
AC Adapter Management
-------------------------------------------------------------------------- */
static int acpi_ac_get_state(struct acpi_ac *ac)
{
acpi_status status = AE_OK;
if (!ac)
return -EINVAL;
status = acpi_evaluate_integer(ac->device->handle, "_PSR", NULL,
&ac->state);
if (ACPI_FAILURE(status)) {
ACPI_EXCEPTION((AE_INFO, status,
"Error reading AC Adapter state"));
ac->state = ACPI_AC_STATUS_UNKNOWN;
return -ENODEV;
}
return 0;
}
/* --------------------------------------------------------------------------
sysfs I/F
-------------------------------------------------------------------------- */
static int get_ac_property(struct power_supply *psy,
enum power_supply_property psp,
union power_supply_propval *val)
{
struct acpi_ac *ac = to_acpi_ac(psy);
if (!ac)
return -ENODEV;
if (acpi_ac_get_state(ac))
return -ENODEV;
switch (psp) {
case POWER_SUPPLY_PROP_ONLINE:
val->intval = ac->state;
break;
default:
return -EINVAL;
}
return 0;
}
static enum power_supply_property ac_props[] = {
POWER_SUPPLY_PROP_ONLINE,
};
#ifdef CONFIG_ACPI_PROCFS_POWER
/* --------------------------------------------------------------------------
FS Interface (/proc)
-------------------------------------------------------------------------- */
static struct proc_dir_entry *acpi_ac_dir;
static int acpi_ac_seq_show(struct seq_file *seq, void *offset)
{
struct acpi_ac *ac = seq->private;
if (!ac)
return 0;
if (acpi_ac_get_state(ac)) {
seq_puts(seq, "ERROR: Unable to read AC Adapter state\n");
return 0;
}
seq_puts(seq, "state: ");
switch (ac->state) {
case ACPI_AC_STATUS_OFFLINE:
seq_puts(seq, "off-line\n");
break;
case ACPI_AC_STATUS_ONLINE:
seq_puts(seq, "on-line\n");
break;
default:
seq_puts(seq, "unknown\n");
break;
}
return 0;
}
static int acpi_ac_open_fs(struct inode *inode, struct file *file)
{
return single_open(file, acpi_ac_seq_show, PDE_DATA(inode));
}
static int acpi_ac_add_fs(struct acpi_ac *ac)
{
struct proc_dir_entry *entry = NULL;
printk(KERN_WARNING PREFIX "Deprecated procfs I/F for AC is loaded,"
" please retry with CONFIG_ACPI_PROCFS_POWER cleared\n");
if (!acpi_device_dir(ac->device)) {
acpi_device_dir(ac->device) =
proc_mkdir(acpi_device_bid(ac->device), acpi_ac_dir);
if (!acpi_device_dir(ac->device))
return -ENODEV;
}
/* 'state' [R] */
entry = proc_create_data(ACPI_AC_FILE_STATE,
S_IRUGO, acpi_device_dir(ac->device),
&acpi_ac_fops, ac);
if (!entry)
return -ENODEV;
return 0;
}
static int acpi_ac_remove_fs(struct acpi_ac *ac)
{
if (acpi_device_dir(ac->device)) {
remove_proc_entry(ACPI_AC_FILE_STATE,
acpi_device_dir(ac->device));
remove_proc_entry(acpi_device_bid(ac->device), acpi_ac_dir);
acpi_device_dir(ac->device) = NULL;
}
return 0;
}
#endif
/* --------------------------------------------------------------------------
Driver Model
-------------------------------------------------------------------------- */
static void acpi_ac_notify(struct acpi_device *device, u32 event)
{
struct acpi_ac *ac = acpi_driver_data(device);
if (!ac)
return;
switch (event) {
default:
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"Unsupported event [0x%x]\n", event));
case ACPI_AC_NOTIFY_STATUS:
case ACPI_NOTIFY_BUS_CHECK:
case ACPI_NOTIFY_DEVICE_CHECK:
/*
* A buggy BIOS may notify AC first and then sleep for
* a specific time before doing actual operations in the
* EC event handler (_Qxx). This will cause the AC state
* reported by the ACPI event to be incorrect, so wait for a
* specific time for the EC event handler to make progress.
*/
if (ac_sleep_before_get_state_ms > 0)
msleep(ac_sleep_before_get_state_ms);
acpi_ac_get_state(ac);
acpi_bus_generate_netlink_event(device->pnp.device_class,
dev_name(&device->dev), event,
(u32) ac->state);
acpi_notifier_call_chain(device, event, (u32) ac->state);
kobject_uevent(&ac->charger->dev.kobj, KOBJ_CHANGE);
}
return;
}
static int acpi_ac_battery_notify(struct notifier_block *nb,
unsigned long action, void *data)
{
struct acpi_ac *ac = container_of(nb, struct acpi_ac, battery_nb);
struct acpi_bus_event *event = (struct acpi_bus_event *)data;
/*
* On HP Pavilion dv6-6179er AC status notifications aren't triggered
* when adapter is plugged/unplugged. However, battery status
* notifcations are triggered when battery starts charging or
* discharging. Re-reading AC status triggers lost AC notifications,
* if AC status has changed.
*/
if (strcmp(event->device_class, ACPI_BATTERY_CLASS) == 0 &&
event->type == ACPI_BATTERY_NOTIFY_STATUS)
acpi_ac_get_state(ac);
return NOTIFY_OK;
}
static int thinkpad_e530_quirk(const struct dmi_system_id *d)
{
ac_sleep_before_get_state_ms = 1000;
return 0;
}
static struct dmi_system_id ac_dmi_table[] = {
{
.callback = thinkpad_e530_quirk,
.ident = "thinkpad e530",
.matches = {
DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
DMI_MATCH(DMI_PRODUCT_NAME, "32597CG"),
},
},
{},
};
static int acpi_ac_add(struct acpi_device *device)
{
struct power_supply_config psy_cfg = {};
int result = 0;
struct acpi_ac *ac = NULL;
if (!device)
return -EINVAL;
ac = kzalloc(sizeof(struct acpi_ac), GFP_KERNEL);
if (!ac)
return -ENOMEM;
ac->device = device;
strcpy(acpi_device_name(device), ACPI_AC_DEVICE_NAME);
strcpy(acpi_device_class(device), ACPI_AC_CLASS);
device->driver_data = ac;
result = acpi_ac_get_state(ac);
if (result)
goto end;
psy_cfg.drv_data = ac;
ac->charger_desc.name = acpi_device_bid(device);
#ifdef CONFIG_ACPI_PROCFS_POWER
result = acpi_ac_add_fs(ac);
if (result)
goto end;
#endif
ac->charger_desc.type = POWER_SUPPLY_TYPE_MAINS;
ac->charger_desc.properties = ac_props;
ac->charger_desc.num_properties = ARRAY_SIZE(ac_props);
ac->charger_desc.get_property = get_ac_property;
ac->charger = power_supply_register(&ac->device->dev,
&ac->charger_desc, &psy_cfg);
if (IS_ERR(ac->charger)) {
result = PTR_ERR(ac->charger);
goto end;
}
printk(KERN_INFO PREFIX "%s [%s] (%s)\n",
acpi_device_name(device), acpi_device_bid(device),
ac->state ? "on-line" : "off-line");
ac->battery_nb.notifier_call = acpi_ac_battery_notify;
register_acpi_notifier(&ac->battery_nb);
end:
if (result) {
#ifdef CONFIG_ACPI_PROCFS_POWER
acpi_ac_remove_fs(ac);
#endif
kfree(ac);
}
dmi_check_system(ac_dmi_table);
return result;
}
#ifdef CONFIG_PM_SLEEP
static int acpi_ac_resume(struct device *dev)
{
struct acpi_ac *ac;
unsigned old_state;
if (!dev)
return -EINVAL;
ac = acpi_driver_data(to_acpi_device(dev));
if (!ac)
return -EINVAL;
old_state = ac->state;
if (acpi_ac_get_state(ac))
return 0;
if (old_state != ac->state)
kobject_uevent(&ac->charger->dev.kobj, KOBJ_CHANGE);
return 0;
}
#else
#define acpi_ac_resume NULL
#endif
static int acpi_ac_remove(struct acpi_device *device)
{
struct acpi_ac *ac = NULL;
if (!device || !acpi_driver_data(device))
return -EINVAL;
ac = acpi_driver_data(device);
power_supply_unregister(ac->charger);
unregister_acpi_notifier(&ac->battery_nb);
#ifdef CONFIG_ACPI_PROCFS_POWER
acpi_ac_remove_fs(ac);
#endif
kfree(ac);
return 0;
}
static int __init acpi_ac_init(void)
{
int result;
if (acpi_disabled)
return -ENODEV;
#ifdef CONFIG_ACPI_PROCFS_POWER
acpi_ac_dir = acpi_lock_ac_dir();
if (!acpi_ac_dir)
return -ENODEV;
#endif
result = acpi_bus_register_driver(&acpi_ac_driver);
if (result < 0) {
#ifdef CONFIG_ACPI_PROCFS_POWER
acpi_unlock_ac_dir(acpi_ac_dir);
#endif
return -ENODEV;
}
return 0;
}
static void __exit acpi_ac_exit(void)
{
acpi_bus_unregister_driver(&acpi_ac_driver);
#ifdef CONFIG_ACPI_PROCFS_POWER
acpi_unlock_ac_dir(acpi_ac_dir);
#endif
}
module_init(acpi_ac_init);
module_exit(acpi_ac_exit);