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-rw-r--r--drivers/s390/char/monreader.c533
1 files changed, 533 insertions, 0 deletions
diff --git a/drivers/s390/char/monreader.c b/drivers/s390/char/monreader.c
new file mode 100644
index 000000000..9fa92e45e
--- /dev/null
+++ b/drivers/s390/char/monreader.c
@@ -0,0 +1,533 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Character device driver for reading z/VM *MONITOR service records.
+ *
+ * Copyright IBM Corp. 2004, 2009
+ *
+ * Author: Gerald Schaefer <gerald.schaefer@de.ibm.com>
+ */
+
+#define KMSG_COMPONENT "monreader"
+#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
+
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/init.h>
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/miscdevice.h>
+#include <linux/ctype.h>
+#include <linux/spinlock.h>
+#include <linux/interrupt.h>
+#include <linux/poll.h>
+#include <linux/slab.h>
+#include <net/iucv/iucv.h>
+#include <linux/uaccess.h>
+#include <asm/ebcdic.h>
+#include <asm/extmem.h>
+
+
+#define MON_COLLECT_SAMPLE 0x80
+#define MON_COLLECT_EVENT 0x40
+#define MON_SERVICE "*MONITOR"
+#define MON_IN_USE 0x01
+#define MON_MSGLIM 255
+
+static char mon_dcss_name[9] = "MONDCSS\0";
+
+struct mon_msg {
+ u32 pos;
+ u32 mca_offset;
+ struct iucv_message msg;
+ char msglim_reached;
+ char replied_msglim;
+};
+
+struct mon_private {
+ struct iucv_path *path;
+ struct mon_msg *msg_array[MON_MSGLIM];
+ unsigned int write_index;
+ unsigned int read_index;
+ atomic_t msglim_count;
+ atomic_t read_ready;
+ atomic_t iucv_connected;
+ atomic_t iucv_severed;
+};
+
+static unsigned long mon_in_use = 0;
+
+static unsigned long mon_dcss_start;
+static unsigned long mon_dcss_end;
+
+static DECLARE_WAIT_QUEUE_HEAD(mon_read_wait_queue);
+static DECLARE_WAIT_QUEUE_HEAD(mon_conn_wait_queue);
+
+static u8 user_data_connect[16] = {
+ /* Version code, must be 0x01 for shared mode */
+ 0x01,
+ /* what to collect */
+ MON_COLLECT_SAMPLE | MON_COLLECT_EVENT,
+ /* DCSS name in EBCDIC, 8 bytes padded with blanks */
+ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+};
+
+static u8 user_data_sever[16] = {
+ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+};
+
+/******************************************************************************
+ * helper functions *
+ *****************************************************************************/
+/*
+ * Create the 8 bytes EBCDIC DCSS segment name from
+ * an ASCII name, incl. padding
+ */
+static void dcss_mkname(char *ascii_name, char *ebcdic_name)
+{
+ int i;
+
+ for (i = 0; i < 8; i++) {
+ if (ascii_name[i] == '\0')
+ break;
+ ebcdic_name[i] = toupper(ascii_name[i]);
+ }
+ for (; i < 8; i++)
+ ebcdic_name[i] = ' ';
+ ASCEBC(ebcdic_name, 8);
+}
+
+static inline unsigned long mon_mca_start(struct mon_msg *monmsg)
+{
+ return *(u32 *) &monmsg->msg.rmmsg;
+}
+
+static inline unsigned long mon_mca_end(struct mon_msg *monmsg)
+{
+ return *(u32 *) &monmsg->msg.rmmsg[4];
+}
+
+static inline u8 mon_mca_type(struct mon_msg *monmsg, u8 index)
+{
+ return *((u8 *) mon_mca_start(monmsg) + monmsg->mca_offset + index);
+}
+
+static inline u32 mon_mca_size(struct mon_msg *monmsg)
+{
+ return mon_mca_end(monmsg) - mon_mca_start(monmsg) + 1;
+}
+
+static inline u32 mon_rec_start(struct mon_msg *monmsg)
+{
+ return *((u32 *) (mon_mca_start(monmsg) + monmsg->mca_offset + 4));
+}
+
+static inline u32 mon_rec_end(struct mon_msg *monmsg)
+{
+ return *((u32 *) (mon_mca_start(monmsg) + monmsg->mca_offset + 8));
+}
+
+static int mon_check_mca(struct mon_msg *monmsg)
+{
+ if ((mon_rec_end(monmsg) <= mon_rec_start(monmsg)) ||
+ (mon_rec_start(monmsg) < mon_dcss_start) ||
+ (mon_rec_end(monmsg) > mon_dcss_end) ||
+ (mon_mca_type(monmsg, 0) == 0) ||
+ (mon_mca_size(monmsg) % 12 != 0) ||
+ (mon_mca_end(monmsg) <= mon_mca_start(monmsg)) ||
+ (mon_mca_end(monmsg) > mon_dcss_end) ||
+ (mon_mca_start(monmsg) < mon_dcss_start) ||
+ ((mon_mca_type(monmsg, 1) == 0) && (mon_mca_type(monmsg, 2) == 0)))
+ return -EINVAL;
+ return 0;
+}
+
+static int mon_send_reply(struct mon_msg *monmsg,
+ struct mon_private *monpriv)
+{
+ int rc;
+
+ rc = iucv_message_reply(monpriv->path, &monmsg->msg,
+ IUCV_IPRMDATA, NULL, 0);
+ atomic_dec(&monpriv->msglim_count);
+ if (likely(!monmsg->msglim_reached)) {
+ monmsg->pos = 0;
+ monmsg->mca_offset = 0;
+ monpriv->read_index = (monpriv->read_index + 1) %
+ MON_MSGLIM;
+ atomic_dec(&monpriv->read_ready);
+ } else
+ monmsg->replied_msglim = 1;
+ if (rc) {
+ pr_err("Reading monitor data failed with rc=%i\n", rc);
+ return -EIO;
+ }
+ return 0;
+}
+
+static void mon_free_mem(struct mon_private *monpriv)
+{
+ int i;
+
+ for (i = 0; i < MON_MSGLIM; i++)
+ kfree(monpriv->msg_array[i]);
+ kfree(monpriv);
+}
+
+static struct mon_private *mon_alloc_mem(void)
+{
+ int i;
+ struct mon_private *monpriv;
+
+ monpriv = kzalloc(sizeof(struct mon_private), GFP_KERNEL);
+ if (!monpriv)
+ return NULL;
+ for (i = 0; i < MON_MSGLIM; i++) {
+ monpriv->msg_array[i] = kzalloc(sizeof(struct mon_msg),
+ GFP_KERNEL);
+ if (!monpriv->msg_array[i]) {
+ mon_free_mem(monpriv);
+ return NULL;
+ }
+ }
+ return monpriv;
+}
+
+static inline void mon_next_mca(struct mon_msg *monmsg)
+{
+ if (likely((mon_mca_size(monmsg) - monmsg->mca_offset) == 12))
+ return;
+ monmsg->mca_offset += 12;
+ monmsg->pos = 0;
+}
+
+static struct mon_msg *mon_next_message(struct mon_private *monpriv)
+{
+ struct mon_msg *monmsg;
+
+ if (!atomic_read(&monpriv->read_ready))
+ return NULL;
+ monmsg = monpriv->msg_array[monpriv->read_index];
+ if (unlikely(monmsg->replied_msglim)) {
+ monmsg->replied_msglim = 0;
+ monmsg->msglim_reached = 0;
+ monmsg->pos = 0;
+ monmsg->mca_offset = 0;
+ monpriv->read_index = (monpriv->read_index + 1) %
+ MON_MSGLIM;
+ atomic_dec(&monpriv->read_ready);
+ return ERR_PTR(-EOVERFLOW);
+ }
+ return monmsg;
+}
+
+
+/******************************************************************************
+ * IUCV handler *
+ *****************************************************************************/
+static void mon_iucv_path_complete(struct iucv_path *path, u8 *ipuser)
+{
+ struct mon_private *monpriv = path->private;
+
+ atomic_set(&monpriv->iucv_connected, 1);
+ wake_up(&mon_conn_wait_queue);
+}
+
+static void mon_iucv_path_severed(struct iucv_path *path, u8 *ipuser)
+{
+ struct mon_private *monpriv = path->private;
+
+ pr_err("z/VM *MONITOR system service disconnected with rc=%i\n",
+ ipuser[0]);
+ iucv_path_sever(path, NULL);
+ atomic_set(&monpriv->iucv_severed, 1);
+ wake_up(&mon_conn_wait_queue);
+ wake_up_interruptible(&mon_read_wait_queue);
+}
+
+static void mon_iucv_message_pending(struct iucv_path *path,
+ struct iucv_message *msg)
+{
+ struct mon_private *monpriv = path->private;
+
+ memcpy(&monpriv->msg_array[monpriv->write_index]->msg,
+ msg, sizeof(*msg));
+ if (atomic_inc_return(&monpriv->msglim_count) == MON_MSGLIM) {
+ pr_warn("The read queue for monitor data is full\n");
+ monpriv->msg_array[monpriv->write_index]->msglim_reached = 1;
+ }
+ monpriv->write_index = (monpriv->write_index + 1) % MON_MSGLIM;
+ atomic_inc(&monpriv->read_ready);
+ wake_up_interruptible(&mon_read_wait_queue);
+}
+
+static struct iucv_handler monreader_iucv_handler = {
+ .path_complete = mon_iucv_path_complete,
+ .path_severed = mon_iucv_path_severed,
+ .message_pending = mon_iucv_message_pending,
+};
+
+/******************************************************************************
+ * file operations *
+ *****************************************************************************/
+static int mon_open(struct inode *inode, struct file *filp)
+{
+ struct mon_private *monpriv;
+ int rc;
+
+ /*
+ * only one user allowed
+ */
+ rc = -EBUSY;
+ if (test_and_set_bit(MON_IN_USE, &mon_in_use))
+ goto out;
+
+ rc = -ENOMEM;
+ monpriv = mon_alloc_mem();
+ if (!monpriv)
+ goto out_use;
+
+ /*
+ * Connect to *MONITOR service
+ */
+ monpriv->path = iucv_path_alloc(MON_MSGLIM, IUCV_IPRMDATA, GFP_KERNEL);
+ if (!monpriv->path)
+ goto out_priv;
+ rc = iucv_path_connect(monpriv->path, &monreader_iucv_handler,
+ MON_SERVICE, NULL, user_data_connect, monpriv);
+ if (rc) {
+ pr_err("Connecting to the z/VM *MONITOR system service "
+ "failed with rc=%i\n", rc);
+ rc = -EIO;
+ goto out_path;
+ }
+ /*
+ * Wait for connection confirmation
+ */
+ wait_event(mon_conn_wait_queue,
+ atomic_read(&monpriv->iucv_connected) ||
+ atomic_read(&monpriv->iucv_severed));
+ if (atomic_read(&monpriv->iucv_severed)) {
+ atomic_set(&monpriv->iucv_severed, 0);
+ atomic_set(&monpriv->iucv_connected, 0);
+ rc = -EIO;
+ goto out_path;
+ }
+ filp->private_data = monpriv;
+ return nonseekable_open(inode, filp);
+
+out_path:
+ iucv_path_free(monpriv->path);
+out_priv:
+ mon_free_mem(monpriv);
+out_use:
+ clear_bit(MON_IN_USE, &mon_in_use);
+out:
+ return rc;
+}
+
+static int mon_close(struct inode *inode, struct file *filp)
+{
+ int rc, i;
+ struct mon_private *monpriv = filp->private_data;
+
+ /*
+ * Close IUCV connection and unregister
+ */
+ if (monpriv->path) {
+ rc = iucv_path_sever(monpriv->path, user_data_sever);
+ if (rc)
+ pr_warn("Disconnecting the z/VM *MONITOR system service failed with rc=%i\n",
+ rc);
+ iucv_path_free(monpriv->path);
+ }
+
+ atomic_set(&monpriv->iucv_severed, 0);
+ atomic_set(&monpriv->iucv_connected, 0);
+ atomic_set(&monpriv->read_ready, 0);
+ atomic_set(&monpriv->msglim_count, 0);
+ monpriv->write_index = 0;
+ monpriv->read_index = 0;
+
+ for (i = 0; i < MON_MSGLIM; i++)
+ kfree(monpriv->msg_array[i]);
+ kfree(monpriv);
+ clear_bit(MON_IN_USE, &mon_in_use);
+ return 0;
+}
+
+static ssize_t mon_read(struct file *filp, char __user *data,
+ size_t count, loff_t *ppos)
+{
+ struct mon_private *monpriv = filp->private_data;
+ struct mon_msg *monmsg;
+ int ret;
+ u32 mce_start;
+
+ monmsg = mon_next_message(monpriv);
+ if (IS_ERR(monmsg))
+ return PTR_ERR(monmsg);
+
+ if (!monmsg) {
+ if (filp->f_flags & O_NONBLOCK)
+ return -EAGAIN;
+ ret = wait_event_interruptible(mon_read_wait_queue,
+ atomic_read(&monpriv->read_ready) ||
+ atomic_read(&monpriv->iucv_severed));
+ if (ret)
+ return ret;
+ if (unlikely(atomic_read(&monpriv->iucv_severed)))
+ return -EIO;
+ monmsg = monpriv->msg_array[monpriv->read_index];
+ }
+
+ if (!monmsg->pos)
+ monmsg->pos = mon_mca_start(monmsg) + monmsg->mca_offset;
+ if (mon_check_mca(monmsg))
+ goto reply;
+
+ /* read monitor control element (12 bytes) first */
+ mce_start = mon_mca_start(monmsg) + monmsg->mca_offset;
+ if ((monmsg->pos >= mce_start) && (monmsg->pos < mce_start + 12)) {
+ count = min(count, (size_t) mce_start + 12 - monmsg->pos);
+ ret = copy_to_user(data, (void *) (unsigned long) monmsg->pos,
+ count);
+ if (ret)
+ return -EFAULT;
+ monmsg->pos += count;
+ if (monmsg->pos == mce_start + 12)
+ monmsg->pos = mon_rec_start(monmsg);
+ goto out_copy;
+ }
+
+ /* read records */
+ if (monmsg->pos <= mon_rec_end(monmsg)) {
+ count = min(count, (size_t) mon_rec_end(monmsg) - monmsg->pos
+ + 1);
+ ret = copy_to_user(data, (void *) (unsigned long) monmsg->pos,
+ count);
+ if (ret)
+ return -EFAULT;
+ monmsg->pos += count;
+ if (monmsg->pos > mon_rec_end(monmsg))
+ mon_next_mca(monmsg);
+ goto out_copy;
+ }
+reply:
+ ret = mon_send_reply(monmsg, monpriv);
+ return ret;
+
+out_copy:
+ *ppos += count;
+ return count;
+}
+
+static __poll_t mon_poll(struct file *filp, struct poll_table_struct *p)
+{
+ struct mon_private *monpriv = filp->private_data;
+
+ poll_wait(filp, &mon_read_wait_queue, p);
+ if (unlikely(atomic_read(&monpriv->iucv_severed)))
+ return EPOLLERR;
+ if (atomic_read(&monpriv->read_ready))
+ return EPOLLIN | EPOLLRDNORM;
+ return 0;
+}
+
+static const struct file_operations mon_fops = {
+ .owner = THIS_MODULE,
+ .open = &mon_open,
+ .release = &mon_close,
+ .read = &mon_read,
+ .poll = &mon_poll,
+ .llseek = noop_llseek,
+};
+
+static struct miscdevice mon_dev = {
+ .name = "monreader",
+ .fops = &mon_fops,
+ .minor = MISC_DYNAMIC_MINOR,
+};
+
+/******************************************************************************
+ * module init/exit *
+ *****************************************************************************/
+static int __init mon_init(void)
+{
+ int rc;
+
+ if (!MACHINE_IS_VM) {
+ pr_err("The z/VM *MONITOR record device driver cannot be "
+ "loaded without z/VM\n");
+ return -ENODEV;
+ }
+
+ /*
+ * Register with IUCV and connect to *MONITOR service
+ */
+ rc = iucv_register(&monreader_iucv_handler, 1);
+ if (rc) {
+ pr_err("The z/VM *MONITOR record device driver failed to "
+ "register with IUCV\n");
+ return rc;
+ }
+
+ rc = segment_type(mon_dcss_name);
+ if (rc < 0) {
+ segment_warning(rc, mon_dcss_name);
+ goto out_iucv;
+ }
+ if (rc != SEG_TYPE_SC) {
+ pr_err("The specified *MONITOR DCSS %s does not have the "
+ "required type SC\n", mon_dcss_name);
+ rc = -EINVAL;
+ goto out_iucv;
+ }
+
+ rc = segment_load(mon_dcss_name, SEGMENT_SHARED,
+ &mon_dcss_start, &mon_dcss_end);
+ if (rc < 0) {
+ segment_warning(rc, mon_dcss_name);
+ rc = -EINVAL;
+ goto out_iucv;
+ }
+ dcss_mkname(mon_dcss_name, &user_data_connect[8]);
+
+ /*
+ * misc_register() has to be the last action in module_init(), because
+ * file operations will be available right after this.
+ */
+ rc = misc_register(&mon_dev);
+ if (rc < 0 )
+ goto out;
+ return 0;
+
+out:
+ segment_unload(mon_dcss_name);
+out_iucv:
+ iucv_unregister(&monreader_iucv_handler, 1);
+ return rc;
+}
+
+static void __exit mon_exit(void)
+{
+ segment_unload(mon_dcss_name);
+ misc_deregister(&mon_dev);
+ iucv_unregister(&monreader_iucv_handler, 1);
+ return;
+}
+
+
+module_init(mon_init);
+module_exit(mon_exit);
+
+module_param_string(mondcss, mon_dcss_name, 9, 0444);
+MODULE_PARM_DESC(mondcss, "Name of DCSS segment to be used for *MONITOR "
+ "service, max. 8 chars. Default is MONDCSS");
+
+MODULE_AUTHOR("Gerald Schaefer <geraldsc@de.ibm.com>");
+MODULE_DESCRIPTION("Character device driver for reading z/VM "
+ "monitor service records.");
+MODULE_LICENSE("GPL");
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-28 17:56:51 +0000