// SPDX-License-Identifier: GPL-2.0
/*
* SCLP Store Data support and sysfs interface
*
* Copyright IBM Corp. 2017
*/
#define KMSG_COMPONENT "sclp_sd"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
#include <linux/completion.h>
#include <linux/kobject.h>
#include <linux/list.h>
#include <linux/printk.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/async.h>
#include <linux/export.h>
#include <linux/mutex.h>
#include <asm/pgalloc.h>
#include "sclp.h"
#define SD_EQ_STORE_DATA 0
#define SD_EQ_HALT 1
#define SD_EQ_SIZE 2
#define SD_DI_CONFIG 3
struct sclp_sd_evbuf {
struct evbuf_header hdr;
u8 eq;
u8 di;
u8 rflags;
u64 :56;
u32 id;
u16 :16;
u8 fmt;
u8 status;
u64 sat;
u64 sa;
u32 esize;
u32 dsize;
} __packed;
struct sclp_sd_sccb {
struct sccb_header hdr;
struct sclp_sd_evbuf evbuf;
} __packed __aligned(PAGE_SIZE);
/**
* struct sclp_sd_data - Result of a Store Data request
* @esize_bytes: Resulting esize in bytes
* @dsize_bytes: Resulting dsize in bytes
* @data: Pointer to data - must be released using vfree()
*/
struct sclp_sd_data {
size_t esize_bytes;
size_t dsize_bytes;
void *data;
};
/**
* struct sclp_sd_listener - Listener for asynchronous Store Data response
* @list: For enqueueing this struct
* @id: Event ID of response to listen for
* @completion: Can be used to wait for response
* @evbuf: Contains the resulting Store Data response after completion
*/
struct sclp_sd_listener {
struct list_head list;
u32 id;
struct completion completion;
struct sclp_sd_evbuf evbuf;
};
/**
* struct sclp_sd_file - Sysfs representation of a Store Data entity
* @kobj: Kobject
* @data_attr: Attribute for accessing data contents
* @data_mutex: Mutex to serialize access and updates to @data
* @data: Data associated with this entity
* @di: DI value associated with this entity
*/
struct sclp_sd_file {
struct kobject kobj;
struct bin_attribute data_attr;
struct mutex data_mutex;
struct sclp_sd_data data;
u8 di;
};
#define to_sd_file(x) container_of(x, struct sclp_sd_file, kobj)
static struct kset *sclp_sd_kset;
static struct sclp_sd_file *config_file;
static LIST_HEAD(sclp_sd_queue);
static DEFINE_SPINLOCK(sclp_sd_queue_lock);
/**
* sclp_sd_listener_add() - Add listener for Store Data responses
* @listener: Listener to add
*/
static void sclp_sd_listener_add(struct sclp_sd_listener *listener)
{
spin_lock_irq(&sclp_sd_queue_lock);
list_add_tail(&listener->list, &sclp_sd_queue);
spin_unlock_irq(&sclp_sd_queue_lock);
}
/**
* sclp_sd_listener_remove() - Remove listener for Store Data responses
* @listener: Listener to remove
*/
static void sclp_sd_listener_remove(struct sclp_sd_listener *listener)
{
spin_lock_irq(&sclp_sd_queue_lock);
list_del(&listener->list);
spin_unlock_irq(&sclp_sd_queue_lock);
}
/**
* sclp_sd_listener_init() - Initialize a Store Data response listener
* @listener: Response listener to initialize
* @id: Event ID to listen for
*
* Initialize a listener for asynchronous Store Data responses. This listener
* can afterwards be used to wait for a specific response and to retrieve
* the associated response data.
*/
static void sclp_sd_listener_init(struct sclp_sd_listener *listener, u32 id)
{
memset(listener, 0, sizeof(*listener));
listener->id = id;
init_completion(&listener->completion);
}
/**
* sclp_sd_receiver() - Receiver for Store Data events
* @evbuf_hdr: Header of received events
*
* Process Store Data events and complete listeners with matching event IDs.
*/
static void sclp_sd_receiver(struct evbuf_header *evbuf_hdr)
{
struct sclp_sd_evbuf *evbuf = (struct sclp_sd_evbuf *) evbuf_hdr;
struct sclp_sd_listener *listener;
int found = 0;
pr_debug("received event (id=0x%08x)\n", evbuf->id);
spin_lock(&sclp_sd_queue_lock);
list_for_each_entry(listener, &sclp_sd_queue, list) {
if (listener->id != evbuf->id)
continue;
listener->evbuf = *evbuf;
complete(&listener->completion);
found = 1;
break;
}
spin_unlock(&sclp_sd_queue_lock);
if (!found)
pr_debug("unsolicited event (id=0x%08x)\n", evbuf->id);
}
static struct sclp_register sclp_sd_register = {
.send_mask = EVTYP_STORE_DATA_MASK,
.receive_mask = EVTYP_STORE_DATA_MASK,
.receiver_fn = sclp_sd_receiver,
};
/**
* sclp_sd_sync() - Perform Store Data request synchronously
* @page: Address of work page - must be below 2GB
* @eq: Input EQ value
* @di: Input DI value
* @sat: Input SAT value
* @sa: Input SA value used to specify the address of the target buffer
* @dsize_ptr: Optional pointer to input and output DSIZE value
* @esize_ptr: Optional pointer to output ESIZE value
*
* Perform Store Data request with specified parameters and wait for completion.
*
* Return %0 on success and store resulting DSIZE and ESIZE values in
* @dsize_ptr and @esize_ptr (if provided). Return non-zero on error.
*/
static int sclp_sd_sync(unsigned long page, u8 eq, u8 di, u64 sat, u64 sa,
u32 *dsize_ptr, u32 *esize_ptr)
{
struct sclp_sd_sccb *sccb = (void *) page;
struct sclp_sd_listener listener;
struct sclp_sd_evbuf *evbuf;
int rc;
sclp_sd_listener_init(&listener, __pa(sccb));
sclp_sd_listener_add(&listener);
/* Prepare SCCB */
memset(sccb, 0, PAGE_SIZE);
sccb->hdr.length = sizeof(sccb->hdr) + sizeof(sccb->evbuf);
evbuf = &sccb->evbuf;
evbuf->hdr.length = sizeof(*evbuf);
evbuf->hdr.type = EVTYP_STORE_DATA;
evbuf->eq = eq;
evbuf->di = di;
evbuf->id = listener.id;
evbuf->fmt = 1;
evbuf->sat = sat;
evbuf->sa = sa;
if (dsize_ptr)
evbuf->dsize = *dsize_ptr;
/* Perform command */
pr_debug("request (eq=%d, di=%d, id=0x%08x)\n", eq, di, listener.id);
rc = sclp_sync_request(SCLP_CMDW_WRITE_EVENT_DATA, sccb);
pr_debug("request done (rc=%d)\n", rc);
if (rc)
goto out;
/* Evaluate response */
if (sccb->hdr.response_code == 0x73f0) {
pr_debug("event not supported\n");
rc = -EIO;
goto out_remove;
}
if (sccb->hdr.response_code != 0x0020 || !(evbuf->hdr.flags & 0x80)) {
rc = -EIO;
goto out;
}
if (!(evbuf->rflags & 0x80)) {
rc = wait_for_completion_interruptible(&listener.completion);
if (rc)
goto out;
evbuf = &listener.evbuf;
}
switch (evbuf->status) {
case 0:
if (dsize_ptr)
*dsize_ptr = evbuf->dsize;
if (esize_ptr)
*esize_ptr = evbuf->esize;
pr_debug("success (dsize=%u, esize=%u)\n", evbuf->dsize,
evbuf->esize);
break;
case 3:
rc = -ENOENT;
break;
default:
rc = -EIO;
break;
}
out:
if (rc && rc != -ENOENT) {
/* Provide some information about what went wrong */
pr_warn("Store Data request failed (eq=%d, di=%d, "
"response=0x%04x, flags=0x%02x, status=%d, rc=%d)\n",
eq, di, sccb->hdr.response_code, evbuf->hdr.flags,
evbuf->status, rc);
}
out_remove:
sclp_sd_listener_remove(&listener);
return rc;
}
/**
* sclp_sd_store_data() - Obtain data for specified Store Data entity
* @result: Resulting data
* @di: DI value associated with this entity
*
* Perform a series of Store Data requests to obtain the size and contents of
* the specified Store Data entity.
*
* Return:
* %0: Success - result is stored in @result. @result->data must be
* released using vfree() after use.
* %-ENOENT: No data available for this entity
* %<0: Other error
*/
static int sclp_sd_store_data(struct sclp_sd_data *result, u8 di)
{
u32 dsize = 0, esize = 0;
unsigned long page, asce = 0;
void *data = NULL;
int rc;
page = __get_free_page(GFP_KERNEL | GFP_DMA);
if (!page)
return -ENOMEM;
/* Get size */
rc = sclp_sd_sync(page, SD_EQ_SIZE, di, 0, 0, &dsize, &esize);
if (rc)
goto out;
if (dsize == 0)
goto out_result;
/* Allocate memory */
data = vzalloc(array_size((size_t)dsize, PAGE_SIZE));
if (!data) {
rc = -ENOMEM;
goto out;
}
/* Get translation table for buffer */
asce = base_asce_alloc((unsigned long) data, dsize);
if (!asce) {
vfree(data);
rc = -ENOMEM;
goto out;
}
/* Get data */
rc = sclp_sd_sync(page, SD_EQ_STORE_DATA, di, asce, (u64) data, &dsize,
&esize);
if (rc) {
/* Cancel running request if interrupted */
if (rc == -ERESTARTSYS)
sclp_sd_sync(page, SD_EQ_HALT, di, 0, 0, NULL, NULL);
vfree(data);
goto out;
}
out_result:
result->esize_bytes = (size_t) esize * PAGE_SIZE;
result->dsize_bytes = (size_t) dsize * PAGE_SIZE;
result->data = data;
out:
base_asce_free(asce);
free_page(page);
return rc;
}
/**
* sclp_sd_data_reset() - Reset Store Data result buffer
* @data: Data buffer to reset
*
* Reset @data to initial state and release associated memory.
*/
static void sclp_sd_data_reset(struct sclp_sd_data *data)
{
vfree(data->data);
data->data = NULL;
data->dsize_bytes = 0;
data->esize_bytes = 0;
}
/**
* sclp_sd_file_release() - Release function for sclp_sd_file object
* @kobj: Kobject embedded in sclp_sd_file object
*/
static void sclp_sd_file_release(struct kobject *kobj)
{
struct sclp_sd_file *sd_file = to_sd_file(kobj);
sclp_sd_data_reset(&sd_file->data);
kfree(sd_file);
}
/**
* sclp_sd_file_update() - Update contents of sclp_sd_file object
* @sd_file: Object to update
*
* Obtain the current version of data associated with the Store Data entity
* @sd_file.
*
* On success, return %0 and generate a KOBJ_CHANGE event to indicate that the
* data may have changed. Return non-zero otherwise.
*/
static int sclp_sd_file_update(struct sclp_sd_file *sd_file)
{
const char *name = kobject_name(&sd_file->kobj);
struct sclp_sd_data data;
int rc;
rc = sclp_sd_store_data(&data, sd_file->di);
if (rc) {
if (rc == -ENOENT) {
pr_info("No data is available for the %s data entity\n",
name);
}
return rc;
}
mutex_lock(&sd_file->data_mutex);
sclp_sd_data_reset(&sd_file->data);
sd_file->data = data;
mutex_unlock(&sd_file->data_mutex);
pr_info("A %zu-byte %s data entity was retrieved\n", data.dsize_bytes,
name);
kobject_uevent(&sd_file->kobj, KOBJ_CHANGE);
return 0;
}
/**
* sclp_sd_file_update_async() - Wrapper for asynchronous update call
* @data: Object to update
* @cookie: Unused
*/
static void sclp_sd_file_update_async(void *data, async_cookie_t cookie)
{
struct sclp_sd_file *sd_file = data;
sclp_sd_file_update(sd_file);
}
/**
* reload_store() - Store function for "reload" sysfs attribute
* @kobj: Kobject of sclp_sd_file object
* @attr: Reload attribute
* @buf: Data written to sysfs attribute
* @count: Count of bytes written
*
* Initiate a reload of the data associated with an sclp_sd_file object.
*/
static ssize_t reload_store(struct kobject *kobj, struct kobj_attribute *attr,
const char *buf, size_t count)
{
struct sclp_sd_file *sd_file = to_sd_file(kobj);
sclp_sd_file_update(sd_file);
return count;
}
static struct kobj_attribute reload_attr = __ATTR_WO(reload);
static struct attribute *sclp_sd_file_default_attrs[] = {
&reload_attr.attr,
NULL,
};
ATTRIBUTE_GROUPS(sclp_sd_file_default);
static struct kobj_type sclp_sd_file_ktype = {
.sysfs_ops = &kobj_sysfs_ops,
.release = sclp_sd_file_release,
.default_groups = sclp_sd_file_default_groups,
};
/**
* data_read() - Read function for "data" sysfs attribute
* @file: Open file pointer
* @kobj: Kobject of sclp_sd_file object
* @attr: Data attribute
* @buffer: Target buffer
* @off: Requested file offset
* @size: Requested number of bytes
*
* Store the requested portion of the Store Data entity contents into the
* specified buffer. Return the number of bytes stored on success, or %0
* on EOF.
*/
static ssize_t data_read(struct file *file, struct kobject *kobj,
struct bin_attribute *attr, char *buffer,
loff_t off, size_t size)
{
struct sclp_sd_file *sd_file = to_sd_file(kobj);
size_t data_size;
char *data;
mutex_lock(&sd_file->data_mutex);
data = sd_file->data.data;
data_size = sd_file->data.dsize_bytes;
if (!data || off >= data_size) {
size = 0;
} else {
if (off + size > data_size)
size = data_size - off;
memcpy(buffer, data + off, size);
}
mutex_unlock(&sd_file->data_mutex);
return size;
}
/**
* sclp_sd_file_create() - Add a sysfs file representing a Store Data entity
* @name: Name of file
* @di: DI value associated with this entity
*
* Create a sysfs directory with the given @name located under
*
* /sys/firmware/sclp_sd/
*
* The files in this directory can be used to access the contents of the Store
* Data entity associated with @DI.
*
* Return pointer to resulting sclp_sd_file object on success, %NULL otherwise.
* The object must be freed by calling kobject_put() on the embedded kobject
* pointer after use.
*/
static __init struct sclp_sd_file *sclp_sd_file_create(const char *name, u8 di)
{
struct sclp_sd_file *sd_file;
int rc;
sd_file = kzalloc(sizeof(*sd_file), GFP_KERNEL);
if (!sd_file)
return NULL;
sd_file->di = di;
mutex_init(&sd_file->data_mutex);
/* Create kobject located under /sys/firmware/sclp_sd/ */
sd_file->kobj.kset = sclp_sd_kset;
rc = kobject_init_and_add(&sd_file->kobj, &sclp_sd_file_ktype, NULL,
"%s", name);
if (rc) {
kobject_put(&sd_file->kobj);
return NULL;
}
sysfs_bin_attr_init(&sd_file->data_attr);
sd_file->data_attr.attr.name = "data";
sd_file->data_attr.attr.mode = 0444;
sd_file->data_attr.read = data_read;
rc = sysfs_create_bin_file(&sd_file->kobj, &sd_file->data_attr);
if (rc) {
kobject_put(&sd_file->kobj);
return NULL;
}
/*
* For completeness only - users interested in entity data should listen
* for KOBJ_CHANGE instead.
*/
kobject_uevent(&sd_file->kobj, KOBJ_ADD);
/* Don't let a slow Store Data request delay further initialization */
async_schedule(sclp_sd_file_update_async, sd_file);
return sd_file;
}
/**
* sclp_sd_init() - Initialize sclp_sd support and register sysfs files
*/
static __init int sclp_sd_init(void)
{
int rc;
rc = sclp_register(&sclp_sd_register);
if (rc)
return rc;
/* Create kset named "sclp_sd" located under /sys/firmware/ */
rc = -ENOMEM;
sclp_sd_kset = kset_create_and_add("sclp_sd", NULL, firmware_kobj);
if (!sclp_sd_kset)
goto err_kset;
rc = -EINVAL;
config_file = sclp_sd_file_create("config", SD_DI_CONFIG);
if (!config_file)
goto err_config;
return 0;
err_config:
kset_unregister(sclp_sd_kset);
err_kset:
sclp_unregister(&sclp_sd_register);
return rc;
}
device_initcall(sclp_sd_init);
