--- /dev/null
+/*
+ * Copyright IBM Corp. 2004, 2010
+ * Interface implementation for communication with the z/VM control program
+ *
+ * Author(s): Christian Borntraeger <borntraeger@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/compat.h>
+#include <linux/kernel.h>
+#include <linux/miscdevice.h>
+#include <linux/slab.h>
+#include <linux/export.h>
+#include <asm/compat.h>
+#include <asm/cpcmd.h>
+#include <asm/debug.h>
+#include <asm/uaccess.h>
+#include "vmcp.h"
+
+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;
+ mutex_init(&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 = 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)
+{
+ ssize_t ret;
+ size_t size;
+ struct vmcp_session *session;
+
+ session = file->private_data;
+ if (mutex_lock_interruptible(&session->mutex))
+ return -ERESTARTSYS;
+ if (!session->response) {
+ mutex_unlock(&session->mutex);
+ return 0;
+ }
+ size = min_t(size_t, session->resp_size, session->bufsize);
+ ret = simple_read_from_buffer(buff, count, ppos,
+ session->response, size);
+
+ mutex_unlock(&session->mutex);
+
+ return ret;
+}
+
+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 = file->private_data;
+ if (mutex_lock_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) {
+ mutex_unlock(&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);
+ mutex_unlock(&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 __user *argp;
+ int temp;
+
+ session = file->private_data;
+ if (is_compat_task())
+ argp = compat_ptr(arg);
+ else
+ argp = (int __user *)arg;
+ if (mutex_lock_interruptible(&session->mutex))
+ return -ERESTARTSYS;
+ switch (cmd) {
+ case VMCP_GETCODE:
+ temp = session->resp_code;
+ mutex_unlock(&session->mutex);
+ return put_user(temp, argp);
+ case VMCP_SETBUF:
+ free_pages((unsigned long)session->response,
+ get_order(session->bufsize));
+ session->response=NULL;
+ temp = get_user(session->bufsize, argp);
+ if (get_order(session->bufsize) > 8) {
+ session->bufsize = PAGE_SIZE;
+ temp = -EINVAL;
+ }
+ mutex_unlock(&session->mutex);
+ return temp;
+ case VMCP_GETSIZE:
+ temp = session->resp_size;
+ mutex_unlock(&session->mutex);
+ return put_user(temp, argp);
+ default:
+ mutex_unlock(&session->mutex);
+ return -ENOIOCTLCMD;
+ }
+}
+
+static const struct file_operations vmcp_fops = {
+ .owner = THIS_MODULE,
+ .open = vmcp_open,
+ .release = vmcp_release,
+ .read = vmcp_read,
+ .write = vmcp_write,
+ .unlocked_ioctl = vmcp_ioctl,
+ .compat_ioctl = vmcp_ioctl,
+ .llseek = no_llseek,
+};
+
+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)
+ return 0;
+
+ vmcp_debug = debug_register("vmcp", 1, 1, 240);
+ if (!vmcp_debug)
+ return -ENOMEM;
+
+ ret = debug_register_view(vmcp_debug, &debug_hex_ascii_view);
+ if (ret) {
+ debug_unregister(vmcp_debug);
+ return ret;
+ }
+
+ ret = misc_register(&vmcp_dev);
+ if (ret)
+ debug_unregister(vmcp_debug);
+ return ret;
+}
+device_initcall(vmcp_init);
Code Review / kvmfornfv.git / blobdiff