linux/drivers/s390/cio/chp.c
Sebastian Ott 87dc8a0128 s390/cio: ensure that a chpid is registered only once
Improve locking in chp_new to make sure that we don't register
the same chpid twice. Chpid registration was synchronized via
the machine check handler thread but we also have codepaths to
look for new chpids triggered independent of that thread (during
IPL or resume from hibernate).

Signed-off-by: Sebastian Ott <sebott@linux.ibm.com>
Reviewed-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2018-07-17 07:27:51 +02:00

832 lines
19 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Copyright IBM Corp. 1999, 2010
* Author(s): Cornelia Huck (cornelia.huck@de.ibm.com)
* Arnd Bergmann (arndb@de.ibm.com)
* Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
*/
#include <linux/bug.h>
#include <linux/workqueue.h>
#include <linux/spinlock.h>
#include <linux/export.h>
#include <linux/sched.h>
#include <linux/init.h>
#include <linux/jiffies.h>
#include <linux/wait.h>
#include <linux/mutex.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <asm/chpid.h>
#include <asm/sclp.h>
#include <asm/crw.h>
#include "cio.h"
#include "css.h"
#include "ioasm.h"
#include "cio_debug.h"
#include "chp.h"
#define to_channelpath(device) container_of(device, struct channel_path, dev)
#define CHP_INFO_UPDATE_INTERVAL 1*HZ
enum cfg_task_t {
cfg_none,
cfg_configure,
cfg_deconfigure
};
/* Map for pending configure tasks. */
static enum cfg_task_t chp_cfg_task[__MAX_CSSID + 1][__MAX_CHPID + 1];
static DEFINE_SPINLOCK(cfg_lock);
/* Map for channel-path status. */
static struct sclp_chp_info chp_info;
static DEFINE_MUTEX(info_lock);
/* Time after which channel-path status may be outdated. */
static unsigned long chp_info_expires;
static struct work_struct cfg_work;
/* Wait queue for configure completion events. */
static wait_queue_head_t cfg_wait_queue;
/* Set vary state for given chpid. */
static void set_chp_logically_online(struct chp_id chpid, int onoff)
{
chpid_to_chp(chpid)->state = onoff;
}
/* On success return 0 if channel-path is varied offline, 1 if it is varied
* online. Return -ENODEV if channel-path is not registered. */
int chp_get_status(struct chp_id chpid)
{
return (chpid_to_chp(chpid) ? chpid_to_chp(chpid)->state : -ENODEV);
}
/**
* chp_get_sch_opm - return opm for subchannel
* @sch: subchannel
*
* Calculate and return the operational path mask (opm) based on the chpids
* used by the subchannel and the status of the associated channel-paths.
*/
u8 chp_get_sch_opm(struct subchannel *sch)
{
struct chp_id chpid;
int opm;
int i;
opm = 0;
chp_id_init(&chpid);
for (i = 0; i < 8; i++) {
opm <<= 1;
chpid.id = sch->schib.pmcw.chpid[i];
if (chp_get_status(chpid) != 0)
opm |= 1;
}
return opm;
}
EXPORT_SYMBOL_GPL(chp_get_sch_opm);
/**
* chp_is_registered - check if a channel-path is registered
* @chpid: channel-path ID
*
* Return non-zero if a channel-path with the given chpid is registered,
* zero otherwise.
*/
int chp_is_registered(struct chp_id chpid)
{
return chpid_to_chp(chpid) != NULL;
}
/*
* Function: s390_vary_chpid
* Varies the specified chpid online or offline
*/
static int s390_vary_chpid(struct chp_id chpid, int on)
{
char dbf_text[15];
int status;
sprintf(dbf_text, on?"varyon%x.%02x":"varyoff%x.%02x", chpid.cssid,
chpid.id);
CIO_TRACE_EVENT(2, dbf_text);
status = chp_get_status(chpid);
if (!on && !status)
return 0;
set_chp_logically_online(chpid, on);
chsc_chp_vary(chpid, on);
return 0;
}
/*
* Channel measurement related functions
*/
static ssize_t chp_measurement_chars_read(struct file *filp,
struct kobject *kobj,
struct bin_attribute *bin_attr,
char *buf, loff_t off, size_t count)
{
struct channel_path *chp;
struct device *device;
device = container_of(kobj, struct device, kobj);
chp = to_channelpath(device);
if (chp->cmg == -1)
return 0;
return memory_read_from_buffer(buf, count, &off, &chp->cmg_chars,
sizeof(chp->cmg_chars));
}
static const struct bin_attribute chp_measurement_chars_attr = {
.attr = {
.name = "measurement_chars",
.mode = S_IRUSR,
},
.size = sizeof(struct cmg_chars),
.read = chp_measurement_chars_read,
};
static void chp_measurement_copy_block(struct cmg_entry *buf,
struct channel_subsystem *css,
struct chp_id chpid)
{
void *area;
struct cmg_entry *entry, reference_buf;
int idx;
if (chpid.id < 128) {
area = css->cub_addr1;
idx = chpid.id;
} else {
area = css->cub_addr2;
idx = chpid.id - 128;
}
entry = area + (idx * sizeof(struct cmg_entry));
do {
memcpy(buf, entry, sizeof(*entry));
memcpy(&reference_buf, entry, sizeof(*entry));
} while (reference_buf.values[0] != buf->values[0]);
}
static ssize_t chp_measurement_read(struct file *filp, struct kobject *kobj,
struct bin_attribute *bin_attr,
char *buf, loff_t off, size_t count)
{
struct channel_path *chp;
struct channel_subsystem *css;
struct device *device;
unsigned int size;
device = container_of(kobj, struct device, kobj);
chp = to_channelpath(device);
css = to_css(chp->dev.parent);
size = sizeof(struct cmg_entry);
/* Only allow single reads. */
if (off || count < size)
return 0;
chp_measurement_copy_block((struct cmg_entry *)buf, css, chp->chpid);
count = size;
return count;
}
static const struct bin_attribute chp_measurement_attr = {
.attr = {
.name = "measurement",
.mode = S_IRUSR,
},
.size = sizeof(struct cmg_entry),
.read = chp_measurement_read,
};
void chp_remove_cmg_attr(struct channel_path *chp)
{
device_remove_bin_file(&chp->dev, &chp_measurement_chars_attr);
device_remove_bin_file(&chp->dev, &chp_measurement_attr);
}
int chp_add_cmg_attr(struct channel_path *chp)
{
int ret;
ret = device_create_bin_file(&chp->dev, &chp_measurement_chars_attr);
if (ret)
return ret;
ret = device_create_bin_file(&chp->dev, &chp_measurement_attr);
if (ret)
device_remove_bin_file(&chp->dev, &chp_measurement_chars_attr);
return ret;
}
/*
* Files for the channel path entries.
*/
static ssize_t chp_status_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct channel_path *chp = to_channelpath(dev);
int status;
mutex_lock(&chp->lock);
status = chp->state;
mutex_unlock(&chp->lock);
return status ? sprintf(buf, "online\n") : sprintf(buf, "offline\n");
}
static ssize_t chp_status_write(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
struct channel_path *cp = to_channelpath(dev);
char cmd[10];
int num_args;
int error;
num_args = sscanf(buf, "%5s", cmd);
if (!num_args)
return count;
if (!strncasecmp(cmd, "on", 2) || !strcmp(cmd, "1")) {
mutex_lock(&cp->lock);
error = s390_vary_chpid(cp->chpid, 1);
mutex_unlock(&cp->lock);
} else if (!strncasecmp(cmd, "off", 3) || !strcmp(cmd, "0")) {
mutex_lock(&cp->lock);
error = s390_vary_chpid(cp->chpid, 0);
mutex_unlock(&cp->lock);
} else
error = -EINVAL;
return error < 0 ? error : count;
}
static DEVICE_ATTR(status, 0644, chp_status_show, chp_status_write);
static ssize_t chp_configure_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct channel_path *cp;
int status;
cp = to_channelpath(dev);
status = chp_info_get_status(cp->chpid);
if (status < 0)
return status;
return snprintf(buf, PAGE_SIZE, "%d\n", status);
}
static int cfg_wait_idle(void);
static ssize_t chp_configure_write(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
struct channel_path *cp;
int val;
char delim;
if (sscanf(buf, "%d %c", &val, &delim) != 1)
return -EINVAL;
if (val != 0 && val != 1)
return -EINVAL;
cp = to_channelpath(dev);
chp_cfg_schedule(cp->chpid, val);
cfg_wait_idle();
return count;
}
static DEVICE_ATTR(configure, 0644, chp_configure_show, chp_configure_write);
static ssize_t chp_type_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct channel_path *chp = to_channelpath(dev);
u8 type;
mutex_lock(&chp->lock);
type = chp->desc.desc;
mutex_unlock(&chp->lock);
return sprintf(buf, "%x\n", type);
}
static DEVICE_ATTR(type, 0444, chp_type_show, NULL);
static ssize_t chp_cmg_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct channel_path *chp = to_channelpath(dev);
if (!chp)
return 0;
if (chp->cmg == -1) /* channel measurements not available */
return sprintf(buf, "unknown\n");
return sprintf(buf, "%x\n", chp->cmg);
}
static DEVICE_ATTR(cmg, 0444, chp_cmg_show, NULL);
static ssize_t chp_shared_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct channel_path *chp = to_channelpath(dev);
if (!chp)
return 0;
if (chp->shared == -1) /* channel measurements not available */
return sprintf(buf, "unknown\n");
return sprintf(buf, "%x\n", chp->shared);
}
static DEVICE_ATTR(shared, 0444, chp_shared_show, NULL);
static ssize_t chp_chid_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct channel_path *chp = to_channelpath(dev);
ssize_t rc;
mutex_lock(&chp->lock);
if (chp->desc_fmt1.flags & 0x10)
rc = sprintf(buf, "%04x\n", chp->desc_fmt1.chid);
else
rc = 0;
mutex_unlock(&chp->lock);
return rc;
}
static DEVICE_ATTR(chid, 0444, chp_chid_show, NULL);
static ssize_t chp_chid_external_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct channel_path *chp = to_channelpath(dev);
ssize_t rc;
mutex_lock(&chp->lock);
if (chp->desc_fmt1.flags & 0x10)
rc = sprintf(buf, "%x\n", chp->desc_fmt1.flags & 0x8 ? 1 : 0);
else
rc = 0;
mutex_unlock(&chp->lock);
return rc;
}
static DEVICE_ATTR(chid_external, 0444, chp_chid_external_show, NULL);
static ssize_t util_string_read(struct file *filp, struct kobject *kobj,
struct bin_attribute *attr, char *buf,
loff_t off, size_t count)
{
struct channel_path *chp = to_channelpath(kobj_to_dev(kobj));
ssize_t rc;
mutex_lock(&chp->lock);
rc = memory_read_from_buffer(buf, count, &off, chp->desc_fmt3.util_str,
sizeof(chp->desc_fmt3.util_str));
mutex_unlock(&chp->lock);
return rc;
}
static BIN_ATTR_RO(util_string,
sizeof(((struct channel_path_desc_fmt3 *)0)->util_str));
static struct bin_attribute *chp_bin_attrs[] = {
&bin_attr_util_string,
NULL,
};
static struct attribute *chp_attrs[] = {
&dev_attr_status.attr,
&dev_attr_configure.attr,
&dev_attr_type.attr,
&dev_attr_cmg.attr,
&dev_attr_shared.attr,
&dev_attr_chid.attr,
&dev_attr_chid_external.attr,
NULL,
};
static struct attribute_group chp_attr_group = {
.attrs = chp_attrs,
.bin_attrs = chp_bin_attrs,
};
static const struct attribute_group *chp_attr_groups[] = {
&chp_attr_group,
NULL,
};
static void chp_release(struct device *dev)
{
struct channel_path *cp;
cp = to_channelpath(dev);
kfree(cp);
}
/**
* chp_update_desc - update channel-path description
* @chp: channel-path
*
* Update the channel-path description of the specified channel-path
* including channel measurement related information.
* Return zero on success, non-zero otherwise.
*/
int chp_update_desc(struct channel_path *chp)
{
int rc;
rc = chsc_determine_fmt0_channel_path_desc(chp->chpid, &chp->desc);
if (rc)
return rc;
/*
* Fetching the following data is optional. Not all machines or
* hypervisors implement the required chsc commands.
*/
chsc_determine_fmt1_channel_path_desc(chp->chpid, &chp->desc_fmt1);
chsc_determine_fmt3_channel_path_desc(chp->chpid, &chp->desc_fmt3);
chsc_get_channel_measurement_chars(chp);
return 0;
}
/**
* chp_new - register a new channel-path
* @chpid: channel-path ID
*
* Create and register data structure representing new channel-path. Return
* zero on success, non-zero otherwise.
*/
int chp_new(struct chp_id chpid)
{
struct channel_subsystem *css = css_by_id(chpid.cssid);
struct channel_path *chp;
int ret = 0;
mutex_lock(&css->mutex);
if (chp_is_registered(chpid))
goto out;
chp = kzalloc(sizeof(struct channel_path), GFP_KERNEL);
if (!chp) {
ret = -ENOMEM;
goto out;
}
/* fill in status, etc. */
chp->chpid = chpid;
chp->state = 1;
chp->dev.parent = &css->device;
chp->dev.groups = chp_attr_groups;
chp->dev.release = chp_release;
mutex_init(&chp->lock);
/* Obtain channel path description and fill it in. */
ret = chp_update_desc(chp);
if (ret)
goto out_free;
if ((chp->desc.flags & 0x80) == 0) {
ret = -ENODEV;
goto out_free;
}
dev_set_name(&chp->dev, "chp%x.%02x", chpid.cssid, chpid.id);
/* make it known to the system */
ret = device_register(&chp->dev);
if (ret) {
CIO_MSG_EVENT(0, "Could not register chp%x.%02x: %d\n",
chpid.cssid, chpid.id, ret);
put_device(&chp->dev);
goto out;
}
if (css->cm_enabled) {
ret = chp_add_cmg_attr(chp);
if (ret) {
device_unregister(&chp->dev);
goto out;
}
}
css->chps[chpid.id] = chp;
goto out;
out_free:
kfree(chp);
out:
mutex_unlock(&css->mutex);
return ret;
}
/**
* chp_get_chp_desc - return newly allocated channel-path description
* @chpid: channel-path ID
*
* On success return a newly allocated copy of the channel-path description
* data associated with the given channel-path ID. Return %NULL on error.
*/
struct channel_path_desc_fmt0 *chp_get_chp_desc(struct chp_id chpid)
{
struct channel_path *chp;
struct channel_path_desc_fmt0 *desc;
chp = chpid_to_chp(chpid);
if (!chp)
return NULL;
desc = kmalloc(sizeof(*desc), GFP_KERNEL);
if (!desc)
return NULL;
mutex_lock(&chp->lock);
memcpy(desc, &chp->desc, sizeof(*desc));
mutex_unlock(&chp->lock);
return desc;
}
/**
* chp_process_crw - process channel-path status change
* @crw0: channel report-word to handler
* @crw1: second channel-report word (always NULL)
* @overflow: crw overflow indication
*
* Handle channel-report-words indicating that the status of a channel-path
* has changed.
*/
static void chp_process_crw(struct crw *crw0, struct crw *crw1,
int overflow)
{
struct chp_id chpid;
if (overflow) {
css_schedule_eval_all();
return;
}
CIO_CRW_EVENT(2, "CRW reports slct=%d, oflw=%d, "
"chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
crw0->slct, crw0->oflw, crw0->chn, crw0->rsc, crw0->anc,
crw0->erc, crw0->rsid);
/*
* Check for solicited machine checks. These are
* created by reset channel path and need not be
* handled here.
*/
if (crw0->slct) {
CIO_CRW_EVENT(2, "solicited machine check for "
"channel path %02X\n", crw0->rsid);
return;
}
chp_id_init(&chpid);
chpid.id = crw0->rsid;
switch (crw0->erc) {
case CRW_ERC_IPARM: /* Path has come. */
case CRW_ERC_INIT:
chp_new(chpid);
chsc_chp_online(chpid);
break;
case CRW_ERC_PERRI: /* Path has gone. */
case CRW_ERC_PERRN:
chsc_chp_offline(chpid);
break;
default:
CIO_CRW_EVENT(2, "Don't know how to handle erc=%x\n",
crw0->erc);
}
}
int chp_ssd_get_mask(struct chsc_ssd_info *ssd, struct chp_link *link)
{
int i;
int mask;
for (i = 0; i < 8; i++) {
mask = 0x80 >> i;
if (!(ssd->path_mask & mask))
continue;
if (!chp_id_is_equal(&ssd->chpid[i], &link->chpid))
continue;
if ((ssd->fla_valid_mask & mask) &&
((ssd->fla[i] & link->fla_mask) != link->fla))
continue;
return mask;
}
return 0;
}
EXPORT_SYMBOL_GPL(chp_ssd_get_mask);
static inline int info_bit_num(struct chp_id id)
{
return id.id + id.cssid * (__MAX_CHPID + 1);
}
/* Force chp_info refresh on next call to info_validate(). */
static void info_expire(void)
{
mutex_lock(&info_lock);
chp_info_expires = jiffies - 1;
mutex_unlock(&info_lock);
}
/* Ensure that chp_info is up-to-date. */
static int info_update(void)
{
int rc;
mutex_lock(&info_lock);
rc = 0;
if (time_after(jiffies, chp_info_expires)) {
/* Data is too old, update. */
rc = sclp_chp_read_info(&chp_info);
chp_info_expires = jiffies + CHP_INFO_UPDATE_INTERVAL ;
}
mutex_unlock(&info_lock);
return rc;
}
/**
* chp_info_get_status - retrieve configure status of a channel-path
* @chpid: channel-path ID
*
* On success, return 0 for standby, 1 for configured, 2 for reserved,
* 3 for not recognized. Return negative error code on error.
*/
int chp_info_get_status(struct chp_id chpid)
{
int rc;
int bit;
rc = info_update();
if (rc)
return rc;
bit = info_bit_num(chpid);
mutex_lock(&info_lock);
if (!chp_test_bit(chp_info.recognized, bit))
rc = CHP_STATUS_NOT_RECOGNIZED;
else if (chp_test_bit(chp_info.configured, bit))
rc = CHP_STATUS_CONFIGURED;
else if (chp_test_bit(chp_info.standby, bit))
rc = CHP_STATUS_STANDBY;
else
rc = CHP_STATUS_RESERVED;
mutex_unlock(&info_lock);
return rc;
}
/* Return configure task for chpid. */
static enum cfg_task_t cfg_get_task(struct chp_id chpid)
{
return chp_cfg_task[chpid.cssid][chpid.id];
}
/* Set configure task for chpid. */
static void cfg_set_task(struct chp_id chpid, enum cfg_task_t cfg)
{
chp_cfg_task[chpid.cssid][chpid.id] = cfg;
}
/* Fetch the first configure task. Set chpid accordingly. */
static enum cfg_task_t chp_cfg_fetch_task(struct chp_id *chpid)
{
enum cfg_task_t t = cfg_none;
chp_id_for_each(chpid) {
t = cfg_get_task(*chpid);
if (t != cfg_none)
break;
}
return t;
}
/* Perform one configure/deconfigure request. Reschedule work function until
* last request. */
static void cfg_func(struct work_struct *work)
{
struct chp_id chpid;
enum cfg_task_t t;
int rc;
spin_lock(&cfg_lock);
t = chp_cfg_fetch_task(&chpid);
spin_unlock(&cfg_lock);
switch (t) {
case cfg_configure:
rc = sclp_chp_configure(chpid);
if (rc)
CIO_MSG_EVENT(2, "chp: sclp_chp_configure(%x.%02x)="
"%d\n", chpid.cssid, chpid.id, rc);
else {
info_expire();
chsc_chp_online(chpid);
}
break;
case cfg_deconfigure:
rc = sclp_chp_deconfigure(chpid);
if (rc)
CIO_MSG_EVENT(2, "chp: sclp_chp_deconfigure(%x.%02x)="
"%d\n", chpid.cssid, chpid.id, rc);
else {
info_expire();
chsc_chp_offline(chpid);
}
break;
case cfg_none:
/* Get updated information after last change. */
info_update();
wake_up_interruptible(&cfg_wait_queue);
return;
}
spin_lock(&cfg_lock);
if (t == cfg_get_task(chpid))
cfg_set_task(chpid, cfg_none);
spin_unlock(&cfg_lock);
schedule_work(&cfg_work);
}
/**
* chp_cfg_schedule - schedule chpid configuration request
* @chpid: channel-path ID
* @configure: Non-zero for configure, zero for deconfigure
*
* Schedule a channel-path configuration/deconfiguration request.
*/
void chp_cfg_schedule(struct chp_id chpid, int configure)
{
CIO_MSG_EVENT(2, "chp_cfg_sched%x.%02x=%d\n", chpid.cssid, chpid.id,
configure);
spin_lock(&cfg_lock);
cfg_set_task(chpid, configure ? cfg_configure : cfg_deconfigure);
spin_unlock(&cfg_lock);
schedule_work(&cfg_work);
}
/**
* chp_cfg_cancel_deconfigure - cancel chpid deconfiguration request
* @chpid: channel-path ID
*
* Cancel an active channel-path deconfiguration request if it has not yet
* been performed.
*/
void chp_cfg_cancel_deconfigure(struct chp_id chpid)
{
CIO_MSG_EVENT(2, "chp_cfg_cancel:%x.%02x\n", chpid.cssid, chpid.id);
spin_lock(&cfg_lock);
if (cfg_get_task(chpid) == cfg_deconfigure)
cfg_set_task(chpid, cfg_none);
spin_unlock(&cfg_lock);
}
static bool cfg_idle(void)
{
struct chp_id chpid;
enum cfg_task_t t;
spin_lock(&cfg_lock);
t = chp_cfg_fetch_task(&chpid);
spin_unlock(&cfg_lock);
return t == cfg_none;
}
static int cfg_wait_idle(void)
{
if (wait_event_interruptible(cfg_wait_queue, cfg_idle()))
return -ERESTARTSYS;
return 0;
}
static int __init chp_init(void)
{
struct chp_id chpid;
int state, ret;
ret = crw_register_handler(CRW_RSC_CPATH, chp_process_crw);
if (ret)
return ret;
INIT_WORK(&cfg_work, cfg_func);
init_waitqueue_head(&cfg_wait_queue);
if (info_update())
return 0;
/* Register available channel-paths. */
chp_id_for_each(&chpid) {
state = chp_info_get_status(chpid);
if (state == CHP_STATUS_CONFIGURED ||
state == CHP_STATUS_STANDBY)
chp_new(chpid);
}
return 0;
}
subsys_initcall(chp_init);