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linux/drivers/pnp/pnpbios/core.c
Rafael J. Wysocki 8314418629 Freezer: make kernel threads nonfreezable by default 
Currently, the freezer treats all tasks as freezable, except for the kernel
threads that explicitly set the PF_NOFREEZE flag for themselves.  This
approach is problematic, since it requires every kernel thread to either
set PF_NOFREEZE explicitly, or call try_to_freeze(), even if it doesn't
care for the freezing of tasks at all.

It seems better to only require the kernel threads that want to or need to
be frozen to use some freezer-related code and to remove any
freezer-related code from the other (nonfreezable) kernel threads, which is
done in this patch.

The patch causes all kernel threads to be nonfreezable by default (ie.  to
have PF_NOFREEZE set by default) and introduces the set_freezable()
function that should be called by the freezable kernel threads in order to
unset PF_NOFREEZE.  It also makes all of the currently freezable kernel
threads call set_freezable(), so it shouldn't cause any (intentional)
change of behaviour to appear.  Additionally, it updates documentation to
describe the freezing of tasks more accurately.

[akpm@linux-foundation.org: build fixes]
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Nigel Cunningham <nigel@nigel.suspend2.net>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Gautham R Shenoy <ego@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-17 10:23:02 -07:00

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/*
* pnpbios -- PnP BIOS driver
*
* This driver provides access to Plug-'n'-Play services provided by
* the PnP BIOS firmware, described in the following documents:
* Plug and Play BIOS Specification, Version 1.0A, 5 May 1994
* Plug and Play BIOS Clarification Paper, 6 October 1994
* Compaq Computer Corporation, Phoenix Technologies Ltd., Intel Corp.
*
* Originally (C) 1998 Christian Schmidt <schmidt@digadd.de>
* Modifications (C) 1998 Tom Lees <tom@lpsg.demon.co.uk>
* Minor reorganizations by David Hinds <dahinds@users.sourceforge.net>
* Further modifications (C) 2001, 2002 by:
* Alan Cox <alan@redhat.com>
* Thomas Hood
* Brian Gerst <bgerst@didntduck.org>
*
* Ported to the PnP Layer and several additional improvements (C) 2002
* by Adam Belay <ambx1@neo.rr.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, 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
*/
/* Change Log
*
* Adam Belay - <ambx1@neo.rr.com> - March 16, 2003
* rev 1.01 Only call pnp_bios_dev_node_info once
* Added pnpbios_print_status
* Added several new error messages and info messages
* Added pnpbios_interface_attach_device
* integrated core and proc init system
* Introduced PNPMODE flags
* Removed some useless includes
*/
#include <linux/types.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/linkage.h>
#include <linux/kernel.h>
#include <linux/pnpbios.h>
#include <linux/device.h>
#include <linux/pnp.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/slab.h>
#include <linux/completion.h>
#include <linux/spinlock.h>
#include <linux/dmi.h>
#include <linux/delay.h>
#include <linux/acpi.h>
#include <linux/freezer.h>
#include <linux/kthread.h>
#include <asm/page.h>
#include <asm/desc.h>
#include <asm/system.h>
#include <asm/byteorder.h>
#include "pnpbios.h"
/*
*
* PnP BIOS INTERFACE
*
*/
static union pnp_bios_install_struct * pnp_bios_install = NULL;
int pnp_bios_present(void)
{
return (pnp_bios_install != NULL);
}
struct pnp_dev_node_info node_info;
/*
*
* DOCKING FUNCTIONS
*
*/
#ifdef CONFIG_HOTPLUG
static int unloading = 0;
static struct completion unload_sem;
/*
* (Much of this belongs in a shared routine somewhere)
*/
static int pnp_dock_event(int dock, struct pnp_docking_station_info *info)
{
char *argv [3], **envp, *buf, *scratch;
int i = 0, value;
if (!current->fs->root) {
return -EAGAIN;
}
if (!(envp = kcalloc(20, sizeof (char *), GFP_KERNEL))) {
return -ENOMEM;
}
if (!(buf = kzalloc(256, GFP_KERNEL))) {
kfree (envp);
return -ENOMEM;
}
/* FIXME: if there are actual users of this, it should be integrated into
* the driver core and use the usual infrastructure like sysfs and uevents */
argv [0] = "/sbin/pnpbios";
argv [1] = "dock";
argv [2] = NULL;
/* minimal command environment */
envp [i++] = "HOME=/";
envp [i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
#ifdef DEBUG
/* hint that policy agent should enter no-stdout debug mode */
envp [i++] = "DEBUG=kernel";
#endif
/* extensible set of named bus-specific parameters,
* supporting multiple driver selection algorithms.
*/
scratch = buf;
/* action: add, remove */
envp [i++] = scratch;
scratch += sprintf (scratch, "ACTION=%s", dock?"add":"remove") + 1;
/* Report the ident for the dock */
envp [i++] = scratch;
scratch += sprintf (scratch, "DOCK=%x/%x/%x",
info->location_id, info->serial, info->capabilities);
envp[i] = NULL;
value = call_usermodehelper (argv [0], argv, envp, 0);
kfree (buf);
kfree (envp);
return 0;
}
/*
* Poll the PnP docking at regular intervals
*/
static int pnp_dock_thread(void * unused)
{
static struct pnp_docking_station_info now;
int docked = -1, d = 0;
set_freezable();
while (!unloading)
{
int status;
/*
* Poll every 2 seconds
*/
msleep_interruptible(2000);
if (try_to_freeze())
continue;
status = pnp_bios_dock_station_info(&now);
switch(status)
{
/*
* No dock to manage
*/
case PNP_FUNCTION_NOT_SUPPORTED:
complete_and_exit(&unload_sem, 0);
case PNP_SYSTEM_NOT_DOCKED:
d = 0;
break;
case PNP_SUCCESS:
d = 1;
break;
default:
pnpbios_print_status( "pnp_dock_thread", status );
continue;
}
if(d != docked)
{
if(pnp_dock_event(d, &now)==0)
{
docked = d;
#if 0
printk(KERN_INFO "PnPBIOS: Docking station %stached\n", docked?"at":"de");
#endif
}
}
}
complete_and_exit(&unload_sem, 0);
}
#endif /* CONFIG_HOTPLUG */
static int pnpbios_get_resources(struct pnp_dev * dev, struct pnp_resource_table * res)
{
u8 nodenum = dev->number;
struct pnp_bios_node * node;
/* just in case */
if(!pnpbios_is_dynamic(dev))
return -EPERM;
node = kzalloc(node_info.max_node_size, GFP_KERNEL);
if (!node)
return -1;
if (pnp_bios_get_dev_node(&nodenum, (char )PNPMODE_DYNAMIC, node)) {
kfree(node);
return -ENODEV;
}
pnpbios_read_resources_from_node(res, node);
dev->active = pnp_is_active(dev);
kfree(node);
return 0;
}
static int pnpbios_set_resources(struct pnp_dev * dev, struct pnp_resource_table * res)
{
u8 nodenum = dev->number;
struct pnp_bios_node * node;
int ret;
/* just in case */
if (!pnpbios_is_dynamic(dev))
return -EPERM;
node = kzalloc(node_info.max_node_size, GFP_KERNEL);
if (!node)
return -1;
if (pnp_bios_get_dev_node(&nodenum, (char )PNPMODE_DYNAMIC, node)) {
kfree(node);
return -ENODEV;
}
if(pnpbios_write_resources_to_node(res, node)<0) {
kfree(node);
return -1;
}
ret = pnp_bios_set_dev_node(node->handle, (char)PNPMODE_DYNAMIC, node);
kfree(node);
if (ret > 0)
ret = -1;
return ret;
}
static void pnpbios_zero_data_stream(struct pnp_bios_node * node)
{
unsigned char * p = (char *)node->data;
unsigned char * end = (char *)(node->data + node->size);
unsigned int len;
int i;
while ((char *)p < (char *)end) {
if(p[0] & 0x80) { /* large tag */
len = (p[2] << 8) | p[1];
p += 3;
} else {
if (((p[0]>>3) & 0x0f) == 0x0f)
return;
len = p[0] & 0x07;
p += 1;
}
for (i = 0; i < len; i++)
p[i] = 0;
p += len;
}
printk(KERN_ERR "PnPBIOS: Resource structure did not contain an end tag.\n");
}
static int pnpbios_disable_resources(struct pnp_dev *dev)
{
struct pnp_bios_node * node;
u8 nodenum = dev->number;
int ret;
/* just in case */
if(dev->flags & PNPBIOS_NO_DISABLE || !pnpbios_is_dynamic(dev))
return -EPERM;
node = kzalloc(node_info.max_node_size, GFP_KERNEL);
if (!node)
return -ENOMEM;
if (pnp_bios_get_dev_node(&nodenum, (char )PNPMODE_DYNAMIC, node)) {
kfree(node);
return -ENODEV;
}
pnpbios_zero_data_stream(node);
ret = pnp_bios_set_dev_node(dev->number, (char)PNPMODE_DYNAMIC, node);
kfree(node);
if (ret > 0)
ret = -1;
return ret;
}
/* PnP Layer support */
struct pnp_protocol pnpbios_protocol = {
.name = "Plug and Play BIOS",
.get = pnpbios_get_resources,
.set = pnpbios_set_resources,
.disable = pnpbios_disable_resources,
};
static int insert_device(struct pnp_dev *dev, struct pnp_bios_node * node)
{
struct list_head * pos;
struct pnp_dev * pnp_dev;
struct pnp_id *dev_id;
char id[8];
/* check if the device is already added */
dev->number = node->handle;
list_for_each (pos, &pnpbios_protocol.devices){
pnp_dev = list_entry(pos, struct pnp_dev, protocol_list);
if (dev->number == pnp_dev->number)
return -1;
}
/* set the initial values for the PnP device */
dev_id = kzalloc(sizeof(struct pnp_id), GFP_KERNEL);
if (!dev_id)
return -1;
pnpid32_to_pnpid(node->eisa_id,id);
memcpy(dev_id->id,id,7);
pnp_add_id(dev_id, dev);
pnpbios_parse_data_stream(dev, node);
dev->active = pnp_is_active(dev);
dev->flags = node->flags;
if (!(dev->flags & PNPBIOS_NO_CONFIG))
dev->capabilities |= PNP_CONFIGURABLE;
if (!(dev->flags & PNPBIOS_NO_DISABLE) && pnpbios_is_dynamic(dev))
dev->capabilities |= PNP_DISABLE;
dev->capabilities |= PNP_READ;
if (pnpbios_is_dynamic(dev))
dev->capabilities |= PNP_WRITE;
if (dev->flags & PNPBIOS_REMOVABLE)
dev->capabilities |= PNP_REMOVABLE;
dev->protocol = &pnpbios_protocol;
/* clear out the damaged flags */
if (!dev->active)
pnp_init_resource_table(&dev->res);
pnp_add_device(dev);
pnpbios_interface_attach_device(node);
return 0;
}
static void __init build_devlist(void)
{
u8 nodenum;
unsigned int nodes_got = 0;
unsigned int devs = 0;
struct pnp_bios_node *node;
struct pnp_dev *dev;
node = kzalloc(node_info.max_node_size, GFP_KERNEL);
if (!node)
return;
for(nodenum=0; nodenum<0xff; ) {
u8 thisnodenum = nodenum;
/* eventually we will want to use PNPMODE_STATIC here but for now
* dynamic will help us catch buggy bioses to add to the blacklist.
*/
if (!pnpbios_dont_use_current_config) {
if (pnp_bios_get_dev_node(&nodenum, (char )PNPMODE_DYNAMIC, node))
break;
} else {
if (pnp_bios_get_dev_node(&nodenum, (char )PNPMODE_STATIC, node))
break;
}
nodes_got++;
dev = kzalloc(sizeof (struct pnp_dev), GFP_KERNEL);
if (!dev)
break;
if(insert_device(dev,node)<0)
kfree(dev);
else
devs++;
if (nodenum <= thisnodenum) {
printk(KERN_ERR "PnPBIOS: build_devlist: Node number 0x%x is out of sequence following node 0x%x. Aborting.\n", (unsigned int)nodenum, (unsigned int)thisnodenum);
break;
}
}
kfree(node);
printk(KERN_INFO "PnPBIOS: %i node%s reported by PnP BIOS; %i recorded by driver\n",
nodes_got, nodes_got != 1 ? "s" : "", devs);
}
/*
*
* INIT AND EXIT
*
*/
static int pnpbios_disabled; /* = 0 */
int pnpbios_dont_use_current_config; /* = 0 */
#ifndef MODULE
static int __init pnpbios_setup(char *str)
{
int invert;
while ((str != NULL) && (*str != '\0')) {
if (strncmp(str, "off", 3) == 0)
pnpbios_disabled=1;
if (strncmp(str, "on", 2) == 0)
pnpbios_disabled=0;
invert = (strncmp(str, "no-", 3) == 0);
if (invert)
str += 3;
if (strncmp(str, "curr", 4) == 0)
pnpbios_dont_use_current_config = invert;
str = strchr(str, ',');
if (str != NULL)
str += strspn(str, ", \t");
}
return 1;
}
__setup("pnpbios=", pnpbios_setup);
#endif
/* PnP BIOS signature: "$PnP" */
#define PNP_SIGNATURE (('$' << 0) + ('P' << 8) + ('n' << 16) + ('P' << 24))
static int __init pnpbios_probe_system(void)
{
union pnp_bios_install_struct *check;
u8 sum;
int length, i;
printk(KERN_INFO "PnPBIOS: Scanning system for PnP BIOS support...\n");
/*
* Search the defined area (0xf0000-0xffff0) for a valid PnP BIOS
* structure and, if one is found, sets up the selectors and
* entry points
*/
for (check = (union pnp_bios_install_struct *) __va(0xf0000);
check < (union pnp_bios_install_struct *) __va(0xffff0);
check = (void *)check + 16) {
if (check->fields.signature != PNP_SIGNATURE)
continue;
printk(KERN_INFO "PnPBIOS: Found PnP BIOS installation structure at 0x%p\n", check);
length = check->fields.length;
if (!length) {
printk(KERN_ERR "PnPBIOS: installation structure is invalid, skipping\n");
continue;
}
for (sum = 0, i = 0; i < length; i++)
sum += check->chars[i];
if (sum) {
printk(KERN_ERR "PnPBIOS: installation structure is corrupted, skipping\n");
continue;
}
if (check->fields.version < 0x10) {
printk(KERN_WARNING "PnPBIOS: PnP BIOS version %d.%d is not supported\n",
check->fields.version >> 4,
check->fields.version & 15);
continue;
}
printk(KERN_INFO "PnPBIOS: PnP BIOS version %d.%d, entry 0x%x:0x%x, dseg 0x%x\n",
check->fields.version >> 4, check->fields.version & 15,
check->fields.pm16cseg, check->fields.pm16offset,
check->fields.pm16dseg);
pnp_bios_install = check;
return 1;
}
printk(KERN_INFO "PnPBIOS: PnP BIOS support was not detected.\n");
return 0;
}
static int __init exploding_pnp_bios(struct dmi_system_id *d)
{
printk(KERN_WARNING "%s detected. Disabling PnPBIOS\n", d->ident);
return 0;
}
static struct dmi_system_id pnpbios_dmi_table[] __initdata = {
{ /* PnPBIOS GPF on boot */
.callback = exploding_pnp_bios,
.ident = "Higraded P14H",
.matches = {
DMI_MATCH(DMI_BIOS_VENDOR, "American Megatrends Inc."),
DMI_MATCH(DMI_BIOS_VERSION, "07.00T"),
DMI_MATCH(DMI_SYS_VENDOR, "Higraded"),
DMI_MATCH(DMI_PRODUCT_NAME, "P14H"),
},
},
{ /* PnPBIOS GPF on boot */
.callback = exploding_pnp_bios,
.ident = "ASUS P4P800",
.matches = {
DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer Inc."),
DMI_MATCH(DMI_BOARD_NAME, "P4P800"),
},
},
{ }
};
static int __init pnpbios_init(void)
{
int ret;
#if defined(CONFIG_PPC_MERGE)
if (check_legacy_ioport(PNPBIOS_BASE))
return -ENODEV;
#endif
if (pnpbios_disabled || dmi_check_system(pnpbios_dmi_table) ||
paravirt_enabled()) {
printk(KERN_INFO "PnPBIOS: Disabled\n");
return -ENODEV;
}
#ifdef CONFIG_PNPACPI
if (!acpi_disabled && !pnpacpi_disabled) {
pnpbios_disabled = 1;
printk(KERN_INFO "PnPBIOS: Disabled by ACPI PNP\n");
return -ENODEV;
}
#endif /* CONFIG_ACPI */
/* scan the system for pnpbios support */
if (!pnpbios_probe_system())
return -ENODEV;
/* make preparations for bios calls */
pnpbios_calls_init(pnp_bios_install);
/* read the node info */
ret = pnp_bios_dev_node_info(&node_info);
if (ret) {
printk(KERN_ERR "PnPBIOS: Unable to get node info. Aborting.\n");
return ret;
}
/* register with the pnp layer */
ret = pnp_register_protocol(&pnpbios_protocol);
if (ret) {
printk(KERN_ERR "PnPBIOS: Unable to register driver. Aborting.\n");
return ret;
}
/* start the proc interface */
ret = pnpbios_proc_init();
if (ret)
printk(KERN_ERR "PnPBIOS: Failed to create proc interface.\n");
/* scan for pnpbios devices */
build_devlist();
pnp_platform_devices = 1;
return 0;
}
subsys_initcall(pnpbios_init);
static int __init pnpbios_thread_init(void)
{
struct task_struct *task;
#if defined(CONFIG_PPC_MERGE)
if (check_legacy_ioport(PNPBIOS_BASE))
return 0;
#endif
if (pnpbios_disabled)
return 0;
#ifdef CONFIG_HOTPLUG
init_completion(&unload_sem);
task = kthread_run(pnp_dock_thread, NULL, "kpnpbiosd");
if (!IS_ERR(task))
unloading = 0;
#endif
return 0;
}
#ifndef MODULE
/* init/main.c calls pnpbios_init early */
/* Start the kernel thread later: */
module_init(pnpbios_thread_init);
#else
/*
* N.B.: Building pnpbios as a module hasn't been fully implemented
*/
MODULE_LICENSE("GPL");
static int __init pnpbios_init_all(void)
{
int r;
r = pnpbios_init();
if (r)
return r;
r = pnpbios_thread_init();
if (r)
return r;
return 0;
}
static void __exit pnpbios_exit(void)
{
#ifdef CONFIG_HOTPLUG
unloading = 1;
wait_for_completion(&unload_sem);
#endif
pnpbios_proc_exit();
/* We ought to free resources here */
return;
}
module_init(pnpbios_init_all);
module_exit(pnpbios_exit);
#endif
EXPORT_SYMBOL(pnpbios_protocol);
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