From 6b979de395c7e1b7e59f74a870e1d1911853eccb Mon Sep 17 00:00:00 2001 From: Christian Borntraeger Date: Sat, 25 Jun 2005 14:55:32 -0700 Subject: [PATCH] s390: add vmcp interface Add interface to issue VM control program commands. Signed-off-by: Martin Schwidefsky Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/s390/char/vmcp.c | 219 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 219 insertions(+) create mode 100644 drivers/s390/char/vmcp.c (limited to 'drivers/s390/char/vmcp.c') diff --git a/drivers/s390/char/vmcp.c b/drivers/s390/char/vmcp.c new file mode 100644 index 00000000000..dfbbf235ca2 --- /dev/null +++ b/drivers/s390/char/vmcp.c @@ -0,0 +1,219 @@ +/* + * Copyright (C) 2004,2005 IBM Corporation + * Interface implementation for communication with the v/VM control program + * Author(s): Christian Borntraeger + * + * + * 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 +#include +#include +#include +#include +#include +#include +#include +#include "vmcp.h" + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Christian Borntraeger "); +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)) + 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", 0, 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); -- cgit v1.2.3-18-g5258