diff options
Diffstat (limited to 'drivers/s390/char/sclp_sd.c')
| -rw-r--r-- | drivers/s390/char/sclp_sd.c | 569 |
1 files changed, 569 insertions, 0 deletions
diff --git a/drivers/s390/char/sclp_sd.c b/drivers/s390/char/sclp_sd.c new file mode 100644 index 000000000..1e244f78f --- /dev/null +++ b/drivers/s390/char/sclp_sd.c @@ -0,0 +1,569 @@ +// 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 + * @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, (u32) (addr_t) 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 + */ +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 + * + * 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, +}; + +static struct kobj_type sclp_sd_file_ktype = { + .sysfs_ops = &kobj_sysfs_ops, + .release = sclp_sd_file_release, + .default_attrs = sclp_sd_file_default_attrs, +}; + +/** + * data_read() - Read function for "read" sysfs attribute + * @kobj: Kobject of sclp_sd_file object + * @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); |