--- /dev/null
+/*
+ * Copyright (C) 2004,2005 IBM Corporation
+ * Interface implementation for communication with the v/VM control program
+ * Author(s): Christian Borntraeger <cborntra@de.ibm.com>
+ *
+ *
+ * z/VMs CP offers the possibility to issue commands via the diagnose code 8
+ * this driver implements a character device that issues these commands and
+ * returns the answer of CP.
+
+ * The idea of this driver is based on cpint from Neale Ferguson and #CP in CMS
+ */
+
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <asm/cpcmd.h>
+#include <asm/debug.h>
+#include <asm/uaccess.h>
+#include "vmcp.h"
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Christian Borntraeger <cborntra@de.ibm.com>");
+MODULE_DESCRIPTION("z/VM CP interface");
+
+static debug_info_t *vmcp_debug;
+
+static int vmcp_open(struct inode *inode, struct file *file)
+{
+ struct vmcp_session *session;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ session = kmalloc(sizeof(*session), GFP_KERNEL);
+ if (!session)
+ return -ENOMEM;
+ session->bufsize = PAGE_SIZE;
+ session->response = NULL;
+ session->resp_size = 0;
+ init_MUTEX(&session->mutex);
+ file->private_data = session;
+ return nonseekable_open(inode, file);
+}
+
+static int vmcp_release(struct inode *inode, struct file *file)
+{
+ struct vmcp_session *session;
+
+ session = (struct vmcp_session *)file->private_data;
+ file->private_data = NULL;
+ free_pages((unsigned long)session->response, get_order(session->bufsize));
+ kfree(session);
+ return 0;
+}
+
+static ssize_t
+vmcp_read(struct file *file, char __user * buff, size_t count, loff_t * ppos)
+{
+ size_t tocopy;
+ struct vmcp_session *session;
+
+ session = (struct vmcp_session *)file->private_data;
+ if (down_interruptible(&session->mutex))
+ return -ERESTARTSYS;
+ if (!session->response) {
+ up(&session->mutex);
+ return 0;
+ }
+ if (*ppos > session->resp_size) {
+ up(&session->mutex);
+ return 0;
+ }
+ tocopy = min(session->resp_size - (size_t) (*ppos), count);
+ tocopy = min(tocopy,session->bufsize - (size_t) (*ppos));
+
+ if (copy_to_user(buff, session->response + (*ppos), tocopy)) {
+ up(&session->mutex);
+ return -EFAULT;
+ }
+ up(&session->mutex);
+ *ppos += tocopy;
+ return tocopy;
+}
+
+static ssize_t
+vmcp_write(struct file *file, const char __user * buff, size_t count,
+ loff_t * ppos)
+{
+ char *cmd;
+ struct vmcp_session *session;
+
+ if (count > 240)
+ return -EINVAL;
+ cmd = kmalloc(count + 1, GFP_KERNEL);
+ if (!cmd)
+ return -ENOMEM;
+ if (copy_from_user(cmd, buff, count)) {
+ kfree(cmd);
+ return -EFAULT;
+ }
+ cmd[count] = '\0';
+ session = (struct vmcp_session *)file->private_data;
+ if (down_interruptible(&session->mutex)) {
+ kfree(cmd);
+ return -ERESTARTSYS;
+ }
+ if (!session->response)
+ session->response = (char *)__get_free_pages(GFP_KERNEL
+ | __GFP_REPEAT | GFP_DMA,
+ get_order(session->bufsize));
+ if (!session->response) {
+ up(&session->mutex);
+ kfree(cmd);
+ return -ENOMEM;
+ }
+ debug_text_event(vmcp_debug, 1, cmd);
+ session->resp_size = __cpcmd(cmd, session->response,
+ session->bufsize,
+ &session->resp_code);
+ up(&session->mutex);
+ kfree(cmd);
+ *ppos = 0; /* reset the file pointer after a command */
+ return count;
+}
+
+
+/*
+ * These ioctls are available, as the semantics of the diagnose 8 call
+ * does not fit very well into a Linux call. Diagnose X'08' is described in
+ * CP Programming Services SC24-6084-00
+ *
+ * VMCP_GETCODE: gives the CP return code back to user space
+ * VMCP_SETBUF: sets the response buffer for the next write call. diagnose 8
+ * expects adjacent pages in real storage and to make matters worse, we
+ * dont know the size of the response. Therefore we default to PAGESIZE and
+ * let userspace to change the response size, if userspace expects a bigger
+ * response
+ */
+static long vmcp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+ struct vmcp_session *session;
+ int temp;
+
+ session = (struct vmcp_session *)file->private_data;
+ if (down_interruptible(&session->mutex))
+ return -ERESTARTSYS;
+ switch (cmd) {
+ case VMCP_GETCODE:
+ temp = session->resp_code;
+ up(&session->mutex);
+ return put_user(temp, (int __user *)arg);
+ case VMCP_SETBUF:
+ free_pages((unsigned long)session->response,
+ get_order(session->bufsize));
+ session->response=NULL;
+ temp = get_user(session->bufsize, (int __user *)arg);
+ if (get_order(session->bufsize) > 8) {
+ session->bufsize = PAGE_SIZE;
+ temp = -EINVAL;
+ }
+ up(&session->mutex);
+ return temp;
+ case VMCP_GETSIZE:
+ temp = session->resp_size;
+ up(&session->mutex);
+ return put_user(temp, (int __user *)arg);
+ default:
+ up(&session->mutex);
+ return -ENOIOCTLCMD;
+ }
+}
+
+static struct file_operations vmcp_fops = {
+ .owner = THIS_MODULE,
+ .open = &vmcp_open,
+ .release = &vmcp_release,
+ .read = &vmcp_read,
+ .llseek = &no_llseek,
+ .write = &vmcp_write,
+ .unlocked_ioctl = &vmcp_ioctl,
+ .compat_ioctl = &vmcp_ioctl
+};
+
+static struct miscdevice vmcp_dev = {
+ .name = "vmcp",
+ .minor = MISC_DYNAMIC_MINOR,
+ .fops = &vmcp_fops,
+};
+
+static int __init vmcp_init(void)
+{
+ int ret;
+
+ if (!MACHINE_IS_VM) {
+ printk(KERN_WARNING
+ "z/VM CP interface is only available under z/VM\n");
+ return -ENODEV;
+ }
+ ret = misc_register(&vmcp_dev);
+ if (!ret)
+ printk(KERN_INFO "z/VM CP interface loaded\n");
+ else
+ printk(KERN_WARNING
+ "z/VM CP interface not loaded. Could not register misc device.\n");
+ vmcp_debug = debug_register("vmcp", 1, 1, 240);
+ debug_register_view(vmcp_debug, &debug_hex_ascii_view);
+ return ret;
+}
+
+static void __exit vmcp_exit(void)
+{
+ WARN_ON(misc_deregister(&vmcp_dev) != 0);
+ debug_unregister(vmcp_debug);
+ printk(KERN_INFO "z/VM CP interface unloaded.\n");
+}
+
+module_init(vmcp_init);
+module_exit(vmcp_exit);
git://git.onelab.eu / linux-2.6.git / blobdiff