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linux/drivers/s390/cio/css.c
Cornelia Huck a55360df40 [S390] cio: Disable channel path measurements on shutdown/reboot. 
Make sure channel path measurements are disabled via a reboot notifier
since we cannot rely on userspace to disable it again after enabling
it. This is 1. clean and 2. makes sure that channel path measurements
do not stay enabled after a reboot not involving a subsystem reset
(which would lead to the channel subsystem scribbling onto random
memory).

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2007-10-12 16:13:00 +02:00

831 lines
19 KiB
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/*
* drivers/s390/cio/css.c
* driver for channel subsystem
*
* Copyright (C) 2002 IBM Deutschland Entwicklung GmbH,
* IBM Corporation
* Author(s): Arnd Bergmann (arndb@de.ibm.com)
* Cornelia Huck (cornelia.huck@de.ibm.com)
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/device.h>
#include <linux/slab.h>
#include <linux/errno.h>
#include <linux/list.h>
#include <linux/reboot.h>
#include "css.h"
#include "cio.h"
#include "cio_debug.h"
#include "ioasm.h"
#include "chsc.h"
#include "device.h"
#include "idset.h"
#include "chp.h"
int css_init_done = 0;
static int need_reprobe = 0;
static int max_ssid = 0;
struct channel_subsystem *channel_subsystems[__MAX_CSSID + 1];
int css_characteristics_avail = 0;
int
for_each_subchannel(int(*fn)(struct subchannel_id, void *), void *data)
{
struct subchannel_id schid;
int ret;
init_subchannel_id(&schid);
ret = -ENODEV;
do {
do {
ret = fn(schid, data);
if (ret)
break;
} while (schid.sch_no++ < __MAX_SUBCHANNEL);
schid.sch_no = 0;
} while (schid.ssid++ < max_ssid);
return ret;
}
static struct subchannel *
css_alloc_subchannel(struct subchannel_id schid)
{
struct subchannel *sch;
int ret;
sch = kmalloc (sizeof (*sch), GFP_KERNEL | GFP_DMA);
if (sch == NULL)
return ERR_PTR(-ENOMEM);
ret = cio_validate_subchannel (sch, schid);
if (ret < 0) {
kfree(sch);
return ERR_PTR(ret);
}
if (sch->st != SUBCHANNEL_TYPE_IO) {
/* For now we ignore all non-io subchannels. */
kfree(sch);
return ERR_PTR(-EINVAL);
}
/*
* Set intparm to subchannel address.
* This is fine even on 64bit since the subchannel is always located
* under 2G.
*/
sch->schib.pmcw.intparm = (__u32)(unsigned long)sch;
ret = cio_modify(sch);
if (ret) {
kfree(sch->lock);
kfree(sch);
return ERR_PTR(ret);
}
return sch;
}
static void
css_free_subchannel(struct subchannel *sch)
{
if (sch) {
/* Reset intparm to zeroes. */
sch->schib.pmcw.intparm = 0;
cio_modify(sch);
kfree(sch->lock);
kfree(sch);
}
}
static void
css_subchannel_release(struct device *dev)
{
struct subchannel *sch;
sch = to_subchannel(dev);
if (!cio_is_console(sch->schid)) {
kfree(sch->lock);
kfree(sch);
}
}
static int css_sch_device_register(struct subchannel *sch)
{
int ret;
mutex_lock(&sch->reg_mutex);
ret = device_register(&sch->dev);
mutex_unlock(&sch->reg_mutex);
return ret;
}
void css_sch_device_unregister(struct subchannel *sch)
{
mutex_lock(&sch->reg_mutex);
device_unregister(&sch->dev);
mutex_unlock(&sch->reg_mutex);
}
static void ssd_from_pmcw(struct chsc_ssd_info *ssd, struct pmcw *pmcw)
{
int i;
int mask;
memset(ssd, 0, sizeof(struct chsc_ssd_info));
ssd->path_mask = pmcw->pim;
for (i = 0; i < 8; i++) {
mask = 0x80 >> i;
if (pmcw->pim & mask) {
chp_id_init(&ssd->chpid[i]);
ssd->chpid[i].id = pmcw->chpid[i];
}
}
}
static void ssd_register_chpids(struct chsc_ssd_info *ssd)
{
int i;
int mask;
for (i = 0; i < 8; i++) {
mask = 0x80 >> i;
if (ssd->path_mask & mask)
if (!chp_is_registered(ssd->chpid[i]))
chp_new(ssd->chpid[i]);
}
}
void css_update_ssd_info(struct subchannel *sch)
{
int ret;
if (cio_is_console(sch->schid)) {
/* Console is initialized too early for functions requiring
* memory allocation. */
ssd_from_pmcw(&sch->ssd_info, &sch->schib.pmcw);
} else {
ret = chsc_get_ssd_info(sch->schid, &sch->ssd_info);
if (ret)
ssd_from_pmcw(&sch->ssd_info, &sch->schib.pmcw);
ssd_register_chpids(&sch->ssd_info);
}
}
static int css_register_subchannel(struct subchannel *sch)
{
int ret;
/* Initialize the subchannel structure */
sch->dev.parent = &channel_subsystems[0]->device;
sch->dev.bus = &css_bus_type;
sch->dev.release = &css_subchannel_release;
sch->dev.groups = subch_attr_groups;
css_update_ssd_info(sch);
/* make it known to the system */
ret = css_sch_device_register(sch);
if (ret) {
CIO_MSG_EVENT(0, "Could not register sch 0.%x.%04x: %d\n",
sch->schid.ssid, sch->schid.sch_no, ret);
return ret;
}
return ret;
}
static int css_probe_device(struct subchannel_id schid)
{
int ret;
struct subchannel *sch;
sch = css_alloc_subchannel(schid);
if (IS_ERR(sch))
return PTR_ERR(sch);
ret = css_register_subchannel(sch);
if (ret)
css_free_subchannel(sch);
return ret;
}
static int
check_subchannel(struct device * dev, void * data)
{
struct subchannel *sch;
struct subchannel_id *schid = data;
sch = to_subchannel(dev);
return schid_equal(&sch->schid, schid);
}
struct subchannel *
get_subchannel_by_schid(struct subchannel_id schid)
{
struct device *dev;
dev = bus_find_device(&css_bus_type, NULL,
&schid, check_subchannel);
return dev ? to_subchannel(dev) : NULL;
}
static int css_get_subchannel_status(struct subchannel *sch)
{
struct schib schib;
if (stsch(sch->schid, &schib) || !schib.pmcw.dnv)
return CIO_GONE;
if (sch->schib.pmcw.dnv && (schib.pmcw.dev != sch->schib.pmcw.dev))
return CIO_REVALIDATE;
if (!sch->lpm)
return CIO_NO_PATH;
return CIO_OPER;
}
static int css_evaluate_known_subchannel(struct subchannel *sch, int slow)
{
int event, ret, disc;
unsigned long flags;
enum { NONE, UNREGISTER, UNREGISTER_PROBE, REPROBE } action;
spin_lock_irqsave(sch->lock, flags);
disc = device_is_disconnected(sch);
if (disc && slow) {
/* Disconnected devices are evaluated directly only.*/
spin_unlock_irqrestore(sch->lock, flags);
return 0;
}
/* No interrupt after machine check - kill pending timers. */
device_kill_pending_timer(sch);
if (!disc && !slow) {
/* Non-disconnected devices are evaluated on the slow path. */
spin_unlock_irqrestore(sch->lock, flags);
return -EAGAIN;
}
event = css_get_subchannel_status(sch);
CIO_MSG_EVENT(4, "Evaluating schid 0.%x.%04x, event %d, %s, %s path.\n",
sch->schid.ssid, sch->schid.sch_no, event,
disc ? "disconnected" : "normal",
slow ? "slow" : "fast");
/* Analyze subchannel status. */
action = NONE;
switch (event) {
case CIO_NO_PATH:
if (disc) {
/* Check if paths have become available. */
action = REPROBE;
break;
}
/* fall through */
case CIO_GONE:
/* Prevent unwanted effects when opening lock. */
cio_disable_subchannel(sch);
device_set_disconnected(sch);
/* Ask driver what to do with device. */
action = UNREGISTER;
if (sch->driver && sch->driver->notify) {
spin_unlock_irqrestore(sch->lock, flags);
ret = sch->driver->notify(&sch->dev, event);
spin_lock_irqsave(sch->lock, flags);
if (ret)
action = NONE;
}
break;
case CIO_REVALIDATE:
/* Device will be removed, so no notify necessary. */
if (disc)
/* Reprobe because immediate unregister might block. */
action = REPROBE;
else
action = UNREGISTER_PROBE;
break;
case CIO_OPER:
if (disc)
/* Get device operational again. */
action = REPROBE;
break;
}
/* Perform action. */
ret = 0;
switch (action) {
case UNREGISTER:
case UNREGISTER_PROBE:
/* Unregister device (will use subchannel lock). */
spin_unlock_irqrestore(sch->lock, flags);
css_sch_device_unregister(sch);
spin_lock_irqsave(sch->lock, flags);
/* Reset intparm to zeroes. */
sch->schib.pmcw.intparm = 0;
cio_modify(sch);
break;
case REPROBE:
device_trigger_reprobe(sch);
break;
default:
break;
}
spin_unlock_irqrestore(sch->lock, flags);
/* Probe if necessary. */
if (action == UNREGISTER_PROBE)
ret = css_probe_device(sch->schid);
return ret;
}
static int css_evaluate_new_subchannel(struct subchannel_id schid, int slow)
{
struct schib schib;
if (!slow) {
/* Will be done on the slow path. */
return -EAGAIN;
}
if (stsch_err(schid, &schib) || !schib.pmcw.dnv) {
/* Unusable - ignore. */
return 0;
}
CIO_MSG_EVENT(4, "Evaluating schid 0.%x.%04x, event %d, unknown, "
"slow path.\n", schid.ssid, schid.sch_no, CIO_OPER);
return css_probe_device(schid);
}
static void css_evaluate_subchannel(struct subchannel_id schid, int slow)
{
struct subchannel *sch;
int ret;
sch = get_subchannel_by_schid(schid);
if (sch) {
ret = css_evaluate_known_subchannel(sch, slow);
put_device(&sch->dev);
} else
ret = css_evaluate_new_subchannel(schid, slow);
if (ret == -EAGAIN)
css_schedule_eval(schid);
}
static struct idset *slow_subchannel_set;
static spinlock_t slow_subchannel_lock;
static int __init slow_subchannel_init(void)
{
spin_lock_init(&slow_subchannel_lock);
slow_subchannel_set = idset_sch_new();
if (!slow_subchannel_set) {
CIO_MSG_EVENT(0, "could not allocate slow subchannel set\n");
return -ENOMEM;
}
return 0;
}
static void css_slow_path_func(struct work_struct *unused)
{
struct subchannel_id schid;
CIO_TRACE_EVENT(4, "slowpath");
spin_lock_irq(&slow_subchannel_lock);
init_subchannel_id(&schid);
while (idset_sch_get_first(slow_subchannel_set, &schid)) {
idset_sch_del(slow_subchannel_set, schid);
spin_unlock_irq(&slow_subchannel_lock);
css_evaluate_subchannel(schid, 1);
spin_lock_irq(&slow_subchannel_lock);
}
spin_unlock_irq(&slow_subchannel_lock);
}
static DECLARE_WORK(slow_path_work, css_slow_path_func);
struct workqueue_struct *slow_path_wq;
void css_schedule_eval(struct subchannel_id schid)
{
unsigned long flags;
spin_lock_irqsave(&slow_subchannel_lock, flags);
idset_sch_add(slow_subchannel_set, schid);
queue_work(slow_path_wq, &slow_path_work);
spin_unlock_irqrestore(&slow_subchannel_lock, flags);
}
void css_schedule_eval_all(void)
{
unsigned long flags;
spin_lock_irqsave(&slow_subchannel_lock, flags);
idset_fill(slow_subchannel_set);
queue_work(slow_path_wq, &slow_path_work);
spin_unlock_irqrestore(&slow_subchannel_lock, flags);
}
/* Reprobe subchannel if unregistered. */
static int reprobe_subchannel(struct subchannel_id schid, void *data)
{
struct subchannel *sch;
int ret;
CIO_MSG_EVENT(6, "cio: reprobe 0.%x.%04x\n",
schid.ssid, schid.sch_no);
if (need_reprobe)
return -EAGAIN;
sch = get_subchannel_by_schid(schid);
if (sch) {
/* Already known. */
put_device(&sch->dev);
return 0;
}
ret = css_probe_device(schid);
switch (ret) {
case 0:
break;
case -ENXIO:
case -ENOMEM:
/* These should abort looping */
break;
default:
ret = 0;
}
return ret;
}
/* Work function used to reprobe all unregistered subchannels. */
static void reprobe_all(struct work_struct *unused)
{
int ret;
CIO_MSG_EVENT(2, "reprobe start\n");
need_reprobe = 0;
/* Make sure initial subchannel scan is done. */
wait_event(ccw_device_init_wq,
atomic_read(&ccw_device_init_count) == 0);
ret = for_each_subchannel(reprobe_subchannel, NULL);
CIO_MSG_EVENT(2, "reprobe done (rc=%d, need_reprobe=%d)\n", ret,
need_reprobe);
}
static DECLARE_WORK(css_reprobe_work, reprobe_all);
/* Schedule reprobing of all unregistered subchannels. */
void css_schedule_reprobe(void)
{
need_reprobe = 1;
queue_work(ccw_device_work, &css_reprobe_work);
}
EXPORT_SYMBOL_GPL(css_schedule_reprobe);
/*
* Called from the machine check handler for subchannel report words.
*/
void css_process_crw(int rsid1, int rsid2)
{
struct subchannel_id mchk_schid;
CIO_CRW_EVENT(2, "source is subchannel %04X, subsystem id %x\n",
rsid1, rsid2);
init_subchannel_id(&mchk_schid);
mchk_schid.sch_no = rsid1;
if (rsid2 != 0)
mchk_schid.ssid = (rsid2 >> 8) & 3;
/*
* Since we are always presented with IPI in the CRW, we have to
* use stsch() to find out if the subchannel in question has come
* or gone.
*/
css_evaluate_subchannel(mchk_schid, 0);
}
static int __init
__init_channel_subsystem(struct subchannel_id schid, void *data)
{
struct subchannel *sch;
int ret;
if (cio_is_console(schid))
sch = cio_get_console_subchannel();
else {
sch = css_alloc_subchannel(schid);
if (IS_ERR(sch))
ret = PTR_ERR(sch);
else
ret = 0;
switch (ret) {
case 0:
break;
case -ENOMEM:
panic("Out of memory in init_channel_subsystem\n");
/* -ENXIO: no more subchannels. */
case -ENXIO:
return ret;
/* -EIO: this subchannel set not supported. */
case -EIO:
return ret;
default:
return 0;
}
}
/*
* We register ALL valid subchannels in ioinfo, even those
* that have been present before init_channel_subsystem.
* These subchannels can't have been registered yet (kmalloc
* not working) so we do it now. This is true e.g. for the
* console subchannel.
*/
css_register_subchannel(sch);
return 0;
}
static void __init
css_generate_pgid(struct channel_subsystem *css, u32 tod_high)
{
if (css_characteristics_avail && css_general_characteristics.mcss) {
css->global_pgid.pgid_high.ext_cssid.version = 0x80;
css->global_pgid.pgid_high.ext_cssid.cssid = css->cssid;
} else {
#ifdef CONFIG_SMP
css->global_pgid.pgid_high.cpu_addr = hard_smp_processor_id();
#else
css->global_pgid.pgid_high.cpu_addr = 0;
#endif
}
css->global_pgid.cpu_id = ((cpuid_t *) __LC_CPUID)->ident;
css->global_pgid.cpu_model = ((cpuid_t *) __LC_CPUID)->machine;
css->global_pgid.tod_high = tod_high;
}
static void
channel_subsystem_release(struct device *dev)
{
struct channel_subsystem *css;
css = to_css(dev);
mutex_destroy(&css->mutex);
kfree(css);
}
static ssize_t
css_cm_enable_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct channel_subsystem *css = to_css(dev);
if (!css)
return 0;
return sprintf(buf, "%x\n", css->cm_enabled);
}
static ssize_t
css_cm_enable_store(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
struct channel_subsystem *css = to_css(dev);
int ret;
switch (buf[0]) {
case '0':
ret = css->cm_enabled ? chsc_secm(css, 0) : 0;
break;
case '1':
ret = css->cm_enabled ? 0 : chsc_secm(css, 1);
break;
default:
ret = -EINVAL;
}
return ret < 0 ? ret : count;
}
static DEVICE_ATTR(cm_enable, 0644, css_cm_enable_show, css_cm_enable_store);
static int __init setup_css(int nr)
{
u32 tod_high;
int ret;
struct channel_subsystem *css;
css = channel_subsystems[nr];
memset(css, 0, sizeof(struct channel_subsystem));
css->pseudo_subchannel =
kzalloc(sizeof(*css->pseudo_subchannel), GFP_KERNEL);
if (!css->pseudo_subchannel)
return -ENOMEM;
css->pseudo_subchannel->dev.parent = &css->device;
css->pseudo_subchannel->dev.release = css_subchannel_release;
sprintf(css->pseudo_subchannel->dev.bus_id, "defunct");
ret = cio_create_sch_lock(css->pseudo_subchannel);
if (ret) {
kfree(css->pseudo_subchannel);
return ret;
}
mutex_init(&css->mutex);
css->valid = 1;
css->cssid = nr;
sprintf(css->device.bus_id, "css%x", nr);
css->device.release = channel_subsystem_release;
tod_high = (u32) (get_clock() >> 32);
css_generate_pgid(css, tod_high);
return 0;
}
static int css_reboot_event(struct notifier_block *this,
unsigned long event,
void *ptr)
{
int ret, i;
ret = NOTIFY_DONE;
for (i = 0; i <= __MAX_CSSID; i++) {
struct channel_subsystem *css;
css = channel_subsystems[i];
if (css->cm_enabled)
if (chsc_secm(css, 0))
ret = NOTIFY_BAD;
}
return ret;
}
static struct notifier_block css_reboot_notifier = {
.notifier_call = css_reboot_event,
};
/*
* Now that the driver core is running, we can setup our channel subsystem.
* The struct subchannel's are created during probing (except for the
* static console subchannel).
*/
static int __init
init_channel_subsystem (void)
{
int ret, i;
ret = chsc_determine_css_characteristics();
if (ret == -ENOMEM)
goto out; /* No need to continue. */
if (ret == 0)
css_characteristics_avail = 1;
ret = chsc_alloc_sei_area();
if (ret)
goto out;
ret = slow_subchannel_init();
if (ret)
goto out;
if ((ret = bus_register(&css_bus_type)))
goto out;
/* Try to enable MSS. */
ret = chsc_enable_facility(CHSC_SDA_OC_MSS);
switch (ret) {
case 0: /* Success. */
max_ssid = __MAX_SSID;
break;
case -ENOMEM:
goto out_bus;
default:
max_ssid = 0;
}
/* Setup css structure. */
for (i = 0; i <= __MAX_CSSID; i++) {
struct channel_subsystem *css;
css = kmalloc(sizeof(struct channel_subsystem), GFP_KERNEL);
if (!css) {
ret = -ENOMEM;
goto out_unregister;
}
channel_subsystems[i] = css;
ret = setup_css(i);
if (ret)
goto out_free;
ret = device_register(&css->device);
if (ret)
goto out_free_all;
if (css_characteristics_avail &&
css_chsc_characteristics.secm) {
ret = device_create_file(&css->device,
&dev_attr_cm_enable);
if (ret)
goto out_device;
}
ret = device_register(&css->pseudo_subchannel->dev);
if (ret)
goto out_file;
}
ret = register_reboot_notifier(&css_reboot_notifier);
if (ret)
goto out_pseudo;
css_init_done = 1;
ctl_set_bit(6, 28);
for_each_subchannel(__init_channel_subsystem, NULL);
return 0;
out_pseudo:
device_unregister(&channel_subsystems[i]->pseudo_subchannel->dev);
out_file:
device_remove_file(&channel_subsystems[i]->device,
&dev_attr_cm_enable);
out_device:
device_unregister(&channel_subsystems[i]->device);
out_free_all:
kfree(channel_subsystems[i]->pseudo_subchannel->lock);
kfree(channel_subsystems[i]->pseudo_subchannel);
out_free:
kfree(channel_subsystems[i]);
out_unregister:
while (i > 0) {
struct channel_subsystem *css;
i--;
css = channel_subsystems[i];
device_unregister(&css->pseudo_subchannel->dev);
if (css_characteristics_avail && css_chsc_characteristics.secm)
device_remove_file(&css->device,
&dev_attr_cm_enable);
device_unregister(&css->device);
}
out_bus:
bus_unregister(&css_bus_type);
out:
chsc_free_sei_area();
kfree(slow_subchannel_set);
printk(KERN_WARNING"cio: failed to initialize css driver (%d)!\n",
ret);
return ret;
}
int sch_is_pseudo_sch(struct subchannel *sch)
{
return sch == to_css(sch->dev.parent)->pseudo_subchannel;
}
/*
* find a driver for a subchannel. They identify by the subchannel
* type with the exception that the console subchannel driver has its own
* subchannel type although the device is an i/o subchannel
*/
static int
css_bus_match (struct device *dev, struct device_driver *drv)
{
struct subchannel *sch = container_of (dev, struct subchannel, dev);
struct css_driver *driver = container_of (drv, struct css_driver, drv);
if (sch->st == driver->subchannel_type)
return 1;
return 0;
}
static int
css_probe (struct device *dev)
{
struct subchannel *sch;
sch = to_subchannel(dev);
sch->driver = container_of (dev->driver, struct css_driver, drv);
return (sch->driver->probe ? sch->driver->probe(sch) : 0);
}
static int
css_remove (struct device *dev)
{
struct subchannel *sch;
sch = to_subchannel(dev);
return (sch->driver->remove ? sch->driver->remove(sch) : 0);
}
static void
css_shutdown (struct device *dev)
{
struct subchannel *sch;
sch = to_subchannel(dev);
if (sch->driver->shutdown)
sch->driver->shutdown(sch);
}
struct bus_type css_bus_type = {
.name = "css",
.match = css_bus_match,
.probe = css_probe,
.remove = css_remove,
.shutdown = css_shutdown,
};
subsys_initcall(init_channel_subsystem);
MODULE_LICENSE("GPL");
EXPORT_SYMBOL(css_bus_type);
EXPORT_SYMBOL_GPL(css_characteristics_avail);
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