[S390] Linux API for writing z/VM APPLDATA Monitor records.

This patch delivers a new Linux API in the form of a misc char
device that is useable from user space and allows write access
to the z/VM APPLDATA Monitor Records collected by the *MONITOR
System Service of z/VM.

Signed-off-by: Melissa Howland <melissah@us.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

3 files changed, 299 insertions, 0 deletions

diff --git a/drivers/s390/Kconfig b/drivers/s390/Kconfig
index bc4261e8b606..ae89b9b88743 100644
--- a/drivers/s390/Kconfig
+++ b/drivers/s390/Kconfig
@@ -213,6 +213,12 @@ config MONREADER
         help
           Character device driver for reading z/VM monitor service records
 
+config MONWRITER
+        tristate "API for writing z/VM monitor service records"
+        default "m"
+        help
+          Character device driver for writing z/VM monitor service records
+
 endmenu
 
 menu "Cryptographic devices"
diff --git a/drivers/s390/char/Makefile b/drivers/s390/char/Makefile
index 0c0162ff6c0c..c3e97b4fc186 100644
--- a/drivers/s390/char/Makefile
+++ b/drivers/s390/char/Makefile
@@ -28,3 +28,4 @@ obj-$(CONFIG_S390_TAPE) += tape.o tape_class.o
 obj-$(CONFIG_S390_TAPE_34XX) += tape_34xx.o
 obj-$(CONFIG_S390_TAPE_3590) += tape_3590.o
 obj-$(CONFIG_MONREADER) += monreader.o
+obj-$(CONFIG_MONWRITER) += monwriter.o
diff --git a/drivers/s390/char/monwriter.c b/drivers/s390/char/monwriter.c
new file mode 100644
index 000000000000..1e3939aeb8ab
--- /dev/null
+++ b/drivers/s390/char/monwriter.c
@@ -0,0 +1,292 @@
+/*
+ * drivers/s390/char/monwriter.c
+ *
+ * Character device driver for writing z/VM *MONITOR service records.
+ *
+ * Copyright (C) IBM Corp. 2006
+ *
+ * Author(s): Melissa Howland <Melissa.Howland@us.ibm.com>
+ */
+
+#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/poll.h>
+#include <asm/uaccess.h>
+#include <asm/ebcdic.h>
+#include <asm/io.h>
+#include <asm/appldata.h>
+#include <asm/monwriter.h>
+
+#define MONWRITE_MAX_DATALEN    4024
+
+static int mon_max_bufs = 255;
+
+struct mon_buf {
+        struct list_head list;
+        struct monwrite_hdr hdr;
+        int diag_done;
+        char *data;
+};
+
+struct mon_private {
+        struct list_head list;
+        struct monwrite_hdr hdr;
+        size_t hdr_to_read;
+        size_t data_to_read;
+        struct mon_buf *current_buf;
+        int mon_buf_count;
+};
+
+/*
+ * helper functions
+ */
+
+static int monwrite_diag(struct monwrite_hdr *myhdr, char *buffer, int fcn)
+{
+        struct appldata_product_id id;
+        int rc;
+
+        strcpy(id.prod_nr, "LNXAPPL");
+        id.prod_fn = myhdr->applid;
+        id.record_nr = myhdr->record_num;
+        id.version_nr = myhdr->version;
+        id.release_nr = myhdr->release;
+        id.mod_lvl = myhdr->mod_level;
+        rc = appldata_asm(&id, fcn, (void *) buffer, myhdr->datalen);
+        if (rc <= 0)
+                return rc;
+        if (rc == 5)
+                return -EPERM;
+        printk("DIAG X'DC' error with return code: %i\n", rc);
+        return -EINVAL;
+}
+
+static inline struct mon_buf *monwrite_find_hdr(struct mon_private *monpriv,
+                                                struct monwrite_hdr *monhdr)
+{
+        struct mon_buf *entry, *next;
+
+        list_for_each_entry_safe(entry, next, &monpriv->list, list)
+                if (entry->hdr.applid == monhdr->applid &&
+                    entry->hdr.record_num == monhdr->record_num &&
+                    entry->hdr.version == monhdr->version &&
+                    entry->hdr.release == monhdr->release &&
+                    entry->hdr.mod_level == monhdr->mod_level)
+                        return entry;
+        return NULL;
+}
+
+static int monwrite_new_hdr(struct mon_private *monpriv)
+{
+        struct monwrite_hdr *monhdr = &monpriv->hdr;
+        struct mon_buf *monbuf;
+        int rc;
+
+        if (monhdr->datalen > MONWRITE_MAX_DATALEN ||
+            monhdr->mon_function > MONWRITE_START_CONFIG ||
+            monhdr->hdrlen != sizeof(struct monwrite_hdr))
+                return -EINVAL;
+        monbuf = monwrite_find_hdr(monpriv, monhdr);
+        if (monbuf) {
+                if (monhdr->mon_function == MONWRITE_STOP_INTERVAL) {
+                        monhdr->datalen = monbuf->hdr.datalen;
+                        rc = monwrite_diag(monhdr, monbuf->data,
+                                           APPLDATA_STOP_REC);
+                        list_del(&monbuf->list);
+                        monpriv->mon_buf_count--;
+                        kfree(monbuf->data);
+                        kfree(monbuf);
+                        monbuf = NULL;
+                }
+        } else {
+                if (monpriv->mon_buf_count >= mon_max_bufs)
+                        return -ENOSPC;
+                monbuf = kzalloc(sizeof(struct mon_buf), GFP_KERNEL);
+                if (!monbuf)
+                        return -ENOMEM;
+                monbuf->data = kzalloc(monbuf->hdr.datalen,
+                                       GFP_KERNEL | GFP_DMA);
+                if (!monbuf->data) {
+                        kfree(monbuf);
+                        return -ENOMEM;
+                }
+                monbuf->hdr = *monhdr;
+                list_add_tail(&monbuf->list, &monpriv->list);
+                monpriv->mon_buf_count++;
+        }
+        monpriv->current_buf = monbuf;
+        return 0;
+}
+
+static int monwrite_new_data(struct mon_private *monpriv)
+{
+        struct monwrite_hdr *monhdr = &monpriv->hdr;
+        struct mon_buf *monbuf = monpriv->current_buf;
+        int rc = 0;
+
+        switch (monhdr->mon_function) {
+        case MONWRITE_START_INTERVAL:
+                if (!monbuf->diag_done) {
+                        rc = monwrite_diag(monhdr, monbuf->data,
+                                           APPLDATA_START_INTERVAL_REC);
+                        monbuf->diag_done = 1;
+                }
+                break;
+        case MONWRITE_START_CONFIG:
+                if (!monbuf->diag_done) {
+                        rc = monwrite_diag(monhdr, monbuf->data,
+                                           APPLDATA_START_CONFIG_REC);
+                        monbuf->diag_done = 1;
+                }
+                break;
+        case MONWRITE_GEN_EVENT:
+                rc = monwrite_diag(monhdr, monbuf->data,
+                                   APPLDATA_GEN_EVENT_REC);
+                list_del(&monpriv->current_buf->list);
+                kfree(monpriv->current_buf->data);
+                kfree(monpriv->current_buf);
+                monpriv->current_buf = NULL;
+                break;
+        default:
+                /* monhdr->mon_function is checked in monwrite_new_hdr */
+                BUG();
+        }
+        return rc;
+}
+
+/*
+ * file operations
+ */
+
+static int monwrite_open(struct inode *inode, struct file *filp)
+{
+        struct mon_private *monpriv;
+
+        monpriv = kzalloc(sizeof(struct mon_private), GFP_KERNEL);
+        if (!monpriv)
+                return -ENOMEM;
+        INIT_LIST_HEAD(&monpriv->list);
+        monpriv->hdr_to_read = sizeof(monpriv->hdr);
+        filp->private_data = monpriv;
+        return nonseekable_open(inode, filp);
+}
+
+static int monwrite_close(struct inode *inode, struct file *filp)
+{
+        struct mon_private *monpriv = filp->private_data;
+        struct mon_buf *entry, *next;
+
+        list_for_each_entry_safe(entry, next, &monpriv->list, list) {
+                if (entry->hdr.mon_function != MONWRITE_GEN_EVENT)
+                        monwrite_diag(&entry->hdr, entry->data,
+                                      APPLDATA_STOP_REC);
+                monpriv->mon_buf_count--;
+                list_del(&entry->list);
+                kfree(entry->data);
+                kfree(entry);
+        }
+        kfree(monpriv);
+        return 0;
+}
+
+static ssize_t monwrite_write(struct file *filp, const char __user *data,
+                              size_t count, loff_t *ppos)
+{
+        struct mon_private *monpriv = filp->private_data;
+        size_t len, written;
+        void *to;
+        int rc;
+
+        for (written = 0; written < count; ) {
+                if (monpriv->hdr_to_read) {
+                        len = min(count - written, monpriv->hdr_to_read);
+                        to = (char *) &monpriv->hdr +
+                                sizeof(monpriv->hdr) - monpriv->hdr_to_read;
+                        if (copy_from_user(to, data + written, len)) {
+                                rc = -EFAULT;
+                                goto out_error;
+                        }
+                        monpriv->hdr_to_read -= len;
+                        written += len;
+                        if (monpriv->hdr_to_read > 0)
+                                continue;
+                        rc = monwrite_new_hdr(monpriv);
+                        if (rc)
+                                goto out_error;
+                        monpriv->data_to_read = monpriv->current_buf ?
+                                monpriv->current_buf->hdr.datalen : 0;
+                }
+
+                if (monpriv->data_to_read) {
+                        len = min(count - written, monpriv->data_to_read);
+                        to = monpriv->current_buf->data +
+                                monpriv->hdr.datalen - monpriv->data_to_read;
+                        if (copy_from_user(to, data + written, len)) {
+                                rc = -EFAULT;
+                                goto out_error;
+                        }
+                        monpriv->data_to_read -= len;
+                        written += len;
+                        if (monpriv->data_to_read > 0)
+                                continue;
+                        rc = monwrite_new_data(monpriv);
+                        if (rc)
+                                goto out_error;
+                }
+                monpriv->hdr_to_read = sizeof(monpriv->hdr);
+        }
+        return written;
+
+out_error:
+        monpriv->data_to_read = 0;
+        monpriv->hdr_to_read = sizeof(struct monwrite_hdr);
+        return rc;
+}
+
+static struct file_operations monwrite_fops = {
+        .owner   = THIS_MODULE,
+        .open    = &monwrite_open,
+        .release = &monwrite_close,
+        .write   = &monwrite_write,
+};
+
+static struct miscdevice mon_dev = {
+        .name   = "monwriter",
+        .fops   = &monwrite_fops,
+        .minor  = MISC_DYNAMIC_MINOR,
+};
+
+/*
+ * module init/exit
+ */
+
+static int __init mon_init(void)
+{
+        if (MACHINE_IS_VM)
+                return misc_register(&mon_dev);
+        else
+                return -ENODEV;
+}
+
+static void __exit mon_exit(void)
+{
+        WARN_ON(misc_deregister(&mon_dev) != 0);
+}
+
+module_init(mon_init);
+module_exit(mon_exit);
+
+module_param_named(max_bufs, mon_max_bufs, int, 0644);
+MODULE_PARM_DESC(max_bufs, "Maximum number of sample monitor data buffers"
+                 "that can be active at one time");
+
+MODULE_AUTHOR("Melissa Howland <Melissa.Howland@us.ibm.com>");
+MODULE_DESCRIPTION("Character device driver for writing z/VM "
+                   "APPLDATA monitor records.");
+MODULE_LICENSE("GPL");