Christian Borntraeger | 6b979de | 2005-06-25 14:55:32 -0700 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright (C) 2004,2005 IBM Corporation |
| 3 | * Interface implementation for communication with the v/VM control program |
| 4 | * Author(s): Christian Borntraeger <cborntra@de.ibm.com> |
| 5 | * |
| 6 | * |
| 7 | * z/VMs CP offers the possibility to issue commands via the diagnose code 8 |
| 8 | * this driver implements a character device that issues these commands and |
| 9 | * returns the answer of CP. |
| 10 | |
| 11 | * The idea of this driver is based on cpint from Neale Ferguson and #CP in CMS |
| 12 | */ |
| 13 | |
| 14 | #include <linux/fs.h> |
| 15 | #include <linux/init.h> |
| 16 | #include <linux/kernel.h> |
| 17 | #include <linux/miscdevice.h> |
| 18 | #include <linux/module.h> |
| 19 | #include <asm/cpcmd.h> |
| 20 | #include <asm/debug.h> |
| 21 | #include <asm/uaccess.h> |
| 22 | #include "vmcp.h" |
| 23 | |
| 24 | MODULE_LICENSE("GPL"); |
| 25 | MODULE_AUTHOR("Christian Borntraeger <cborntra@de.ibm.com>"); |
| 26 | MODULE_DESCRIPTION("z/VM CP interface"); |
| 27 | |
| 28 | static debug_info_t *vmcp_debug; |
| 29 | |
| 30 | static int vmcp_open(struct inode *inode, struct file *file) |
| 31 | { |
| 32 | struct vmcp_session *session; |
| 33 | |
| 34 | if (!capable(CAP_SYS_ADMIN)) |
| 35 | return -EPERM; |
| 36 | |
| 37 | session = kmalloc(sizeof(*session), GFP_KERNEL); |
| 38 | if (!session) |
| 39 | return -ENOMEM; |
| 40 | session->bufsize = PAGE_SIZE; |
| 41 | session->response = NULL; |
| 42 | session->resp_size = 0; |
| 43 | init_MUTEX(&session->mutex); |
| 44 | file->private_data = session; |
| 45 | return nonseekable_open(inode, file); |
| 46 | } |
| 47 | |
| 48 | static int vmcp_release(struct inode *inode, struct file *file) |
| 49 | { |
| 50 | struct vmcp_session *session; |
| 51 | |
| 52 | session = (struct vmcp_session *)file->private_data; |
| 53 | file->private_data = NULL; |
| 54 | free_pages((unsigned long)session->response, get_order(session->bufsize)); |
| 55 | kfree(session); |
| 56 | return 0; |
| 57 | } |
| 58 | |
| 59 | static ssize_t |
| 60 | vmcp_read(struct file *file, char __user * buff, size_t count, loff_t * ppos) |
| 61 | { |
| 62 | size_t tocopy; |
| 63 | struct vmcp_session *session; |
| 64 | |
| 65 | session = (struct vmcp_session *)file->private_data; |
| 66 | if (down_interruptible(&session->mutex)) |
| 67 | return -ERESTARTSYS; |
| 68 | if (!session->response) { |
| 69 | up(&session->mutex); |
| 70 | return 0; |
| 71 | } |
| 72 | if (*ppos > session->resp_size) { |
| 73 | up(&session->mutex); |
| 74 | return 0; |
| 75 | } |
| 76 | tocopy = min(session->resp_size - (size_t) (*ppos), count); |
| 77 | tocopy = min(tocopy,session->bufsize - (size_t) (*ppos)); |
| 78 | |
| 79 | if (copy_to_user(buff, session->response + (*ppos), tocopy)) { |
| 80 | up(&session->mutex); |
| 81 | return -EFAULT; |
| 82 | } |
| 83 | up(&session->mutex); |
| 84 | *ppos += tocopy; |
| 85 | return tocopy; |
| 86 | } |
| 87 | |
| 88 | static ssize_t |
| 89 | vmcp_write(struct file *file, const char __user * buff, size_t count, |
| 90 | loff_t * ppos) |
| 91 | { |
| 92 | char *cmd; |
| 93 | struct vmcp_session *session; |
| 94 | |
| 95 | if (count > 240) |
| 96 | return -EINVAL; |
| 97 | cmd = kmalloc(count + 1, GFP_KERNEL); |
| 98 | if (!cmd) |
| 99 | return -ENOMEM; |
| 100 | if (copy_from_user(cmd, buff, count)) { |
| 101 | kfree(cmd); |
| 102 | return -EFAULT; |
| 103 | } |
| 104 | cmd[count] = '\0'; |
| 105 | session = (struct vmcp_session *)file->private_data; |
| 106 | if (down_interruptible(&session->mutex)) |
| 107 | return -ERESTARTSYS; |
| 108 | if (!session->response) |
| 109 | session->response = (char *)__get_free_pages(GFP_KERNEL |
| 110 | | __GFP_REPEAT | GFP_DMA, |
| 111 | get_order(session->bufsize)); |
| 112 | if (!session->response) { |
| 113 | up(&session->mutex); |
| 114 | kfree(cmd); |
| 115 | return -ENOMEM; |
| 116 | } |
| 117 | debug_text_event(vmcp_debug, 1, cmd); |
| 118 | session->resp_size = cpcmd(cmd, session->response, |
| 119 | session->bufsize, |
| 120 | &session->resp_code); |
| 121 | up(&session->mutex); |
| 122 | kfree(cmd); |
| 123 | *ppos = 0; /* reset the file pointer after a command */ |
| 124 | return count; |
| 125 | } |
| 126 | |
| 127 | |
| 128 | /* |
| 129 | * These ioctls are available, as the semantics of the diagnose 8 call |
| 130 | * does not fit very well into a Linux call. Diagnose X'08' is described in |
| 131 | * CP Programming Services SC24-6084-00 |
| 132 | * |
| 133 | * VMCP_GETCODE: gives the CP return code back to user space |
| 134 | * VMCP_SETBUF: sets the response buffer for the next write call. diagnose 8 |
| 135 | * expects adjacent pages in real storage and to make matters worse, we |
| 136 | * dont know the size of the response. Therefore we default to PAGESIZE and |
| 137 | * let userspace to change the response size, if userspace expects a bigger |
| 138 | * response |
| 139 | */ |
| 140 | static long vmcp_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
| 141 | { |
| 142 | struct vmcp_session *session; |
| 143 | int temp; |
| 144 | |
| 145 | session = (struct vmcp_session *)file->private_data; |
| 146 | if (down_interruptible(&session->mutex)) |
| 147 | return -ERESTARTSYS; |
| 148 | switch (cmd) { |
| 149 | case VMCP_GETCODE: |
| 150 | temp = session->resp_code; |
| 151 | up(&session->mutex); |
| 152 | return put_user(temp, (int __user *)arg); |
| 153 | case VMCP_SETBUF: |
| 154 | free_pages((unsigned long)session->response, |
| 155 | get_order(session->bufsize)); |
| 156 | session->response=NULL; |
| 157 | temp = get_user(session->bufsize, (int __user *)arg); |
| 158 | if (get_order(session->bufsize) > 8) { |
| 159 | session->bufsize = PAGE_SIZE; |
| 160 | temp = -EINVAL; |
| 161 | } |
| 162 | up(&session->mutex); |
| 163 | return temp; |
| 164 | case VMCP_GETSIZE: |
| 165 | temp = session->resp_size; |
| 166 | up(&session->mutex); |
| 167 | return put_user(temp, (int __user *)arg); |
| 168 | default: |
| 169 | up(&session->mutex); |
| 170 | return -ENOIOCTLCMD; |
| 171 | } |
| 172 | } |
| 173 | |
| 174 | static struct file_operations vmcp_fops = { |
| 175 | .owner = THIS_MODULE, |
| 176 | .open = &vmcp_open, |
| 177 | .release = &vmcp_release, |
| 178 | .read = &vmcp_read, |
| 179 | .llseek = &no_llseek, |
| 180 | .write = &vmcp_write, |
| 181 | .unlocked_ioctl = &vmcp_ioctl, |
| 182 | .compat_ioctl = &vmcp_ioctl |
| 183 | }; |
| 184 | |
| 185 | static struct miscdevice vmcp_dev = { |
| 186 | .name = "vmcp", |
| 187 | .minor = MISC_DYNAMIC_MINOR, |
| 188 | .fops = &vmcp_fops, |
| 189 | }; |
| 190 | |
| 191 | static int __init vmcp_init(void) |
| 192 | { |
| 193 | int ret; |
| 194 | |
| 195 | if (!MACHINE_IS_VM) { |
| 196 | printk(KERN_WARNING |
| 197 | "z/VM CP interface is only available under z/VM\n"); |
| 198 | return -ENODEV; |
| 199 | } |
| 200 | ret = misc_register(&vmcp_dev); |
| 201 | if (!ret) |
| 202 | printk(KERN_INFO "z/VM CP interface loaded\n"); |
| 203 | else |
| 204 | printk(KERN_WARNING |
| 205 | "z/VM CP interface not loaded. Could not register misc device.\n"); |
| 206 | vmcp_debug = debug_register("vmcp", 0, 1, 240); |
| 207 | debug_register_view(vmcp_debug, &debug_hex_ascii_view); |
| 208 | return ret; |
| 209 | } |
| 210 | |
| 211 | static void __exit vmcp_exit(void) |
| 212 | { |
| 213 | WARN_ON(misc_deregister(&vmcp_dev) != 0); |
| 214 | debug_unregister(vmcp_debug); |
| 215 | printk(KERN_INFO "z/VM CP interface unloaded.\n"); |
| 216 | } |
| 217 | |
| 218 | module_init(vmcp_init); |
| 219 | module_exit(vmcp_exit); |