1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Character device driver for writing z/VM *MONITOR service records. 4 * 5 * Copyright IBM Corp. 2006, 2009 6 * 7 * Author(s): Melissa Howland <Melissa.Howland@us.ibm.com> 8 */ 9 10 #define KMSG_COMPONENT "monwriter" 11 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt 12 13 #include <linux/module.h> 14 #include <linux/moduleparam.h> 15 #include <linux/init.h> 16 #include <linux/errno.h> 17 #include <linux/types.h> 18 #include <linux/kernel.h> 19 #include <linux/miscdevice.h> 20 #include <linux/ctype.h> 21 #include <linux/poll.h> 22 #include <linux/mutex.h> 23 #include <linux/slab.h> 24 #include <linux/uaccess.h> 25 #include <linux/io.h> 26 #include <asm/ebcdic.h> 27 #include <asm/appldata.h> 28 #include <asm/monwriter.h> 29 30 #define MONWRITE_MAX_DATALEN 4010 31 32 static int mon_max_bufs = 255; 33 static int mon_buf_count; 34 35 struct mon_buf { 36 struct list_head list; 37 struct monwrite_hdr hdr; 38 int diag_done; 39 char *data; 40 }; 41 42 struct mon_private { 43 struct list_head list; 44 struct monwrite_hdr hdr; 45 size_t hdr_to_read; 46 size_t data_to_read; 47 struct mon_buf *current_buf; 48 struct mutex thread_mutex; 49 }; 50 51 /* 52 * helper functions 53 */ 54 55 static int monwrite_diag(struct monwrite_hdr *myhdr, char *buffer, int fcn) 56 { 57 struct appldata_parameter_list *parm_list; 58 struct appldata_product_id *id; 59 int rc; 60 61 id = kmalloc(sizeof(*id), GFP_KERNEL); 62 parm_list = kmalloc(sizeof(*parm_list), GFP_KERNEL); 63 rc = -ENOMEM; 64 if (!id || !parm_list) 65 goto out; 66 memcpy(id->prod_nr, "LNXAPPL", 7); 67 id->prod_fn = myhdr->applid; 68 id->record_nr = myhdr->record_num; 69 id->version_nr = myhdr->version; 70 id->release_nr = myhdr->release; 71 id->mod_lvl = myhdr->mod_level; 72 rc = appldata_asm(parm_list, id, fcn, 73 (void *) buffer, myhdr->datalen); 74 if (rc <= 0) 75 goto out; 76 pr_err("Writing monitor data failed with rc=%i\n", rc); 77 rc = (rc == 5) ? -EPERM : -EINVAL; 78 out: 79 kfree(id); 80 kfree(parm_list); 81 return rc; 82 } 83 84 static struct mon_buf *monwrite_find_hdr(struct mon_private *monpriv, 85 struct monwrite_hdr *monhdr) 86 { 87 struct mon_buf *entry, *next; 88 89 list_for_each_entry_safe(entry, next, &monpriv->list, list) 90 if ((entry->hdr.mon_function == monhdr->mon_function || 91 monhdr->mon_function == MONWRITE_STOP_INTERVAL) && 92 entry->hdr.applid == monhdr->applid && 93 entry->hdr.record_num == monhdr->record_num && 94 entry->hdr.version == monhdr->version && 95 entry->hdr.release == monhdr->release && 96 entry->hdr.mod_level == monhdr->mod_level) 97 return entry; 98 99 return NULL; 100 } 101 102 static int monwrite_new_hdr(struct mon_private *monpriv) 103 { 104 struct monwrite_hdr *monhdr = &monpriv->hdr; 105 struct mon_buf *monbuf; 106 int rc = 0; 107 108 if (monhdr->datalen > MONWRITE_MAX_DATALEN || 109 monhdr->mon_function > MONWRITE_START_CONFIG || 110 monhdr->hdrlen != sizeof(struct monwrite_hdr)) 111 return -EINVAL; 112 monbuf = NULL; 113 if (monhdr->mon_function != MONWRITE_GEN_EVENT) 114 monbuf = monwrite_find_hdr(monpriv, monhdr); 115 if (monbuf) { 116 if (monhdr->mon_function == MONWRITE_STOP_INTERVAL) { 117 monhdr->datalen = monbuf->hdr.datalen; 118 rc = monwrite_diag(monhdr, monbuf->data, 119 APPLDATA_STOP_REC); 120 list_del(&monbuf->list); 121 mon_buf_count--; 122 kfree(monbuf->data); 123 kfree(monbuf); 124 monbuf = NULL; 125 } 126 } else if (monhdr->mon_function != MONWRITE_STOP_INTERVAL) { 127 if (mon_buf_count >= mon_max_bufs) 128 return -ENOSPC; 129 monbuf = kzalloc(sizeof(struct mon_buf), GFP_KERNEL); 130 if (!monbuf) 131 return -ENOMEM; 132 monbuf->data = kzalloc(monhdr->datalen, 133 GFP_KERNEL | GFP_DMA); 134 if (!monbuf->data) { 135 kfree(monbuf); 136 return -ENOMEM; 137 } 138 monbuf->hdr = *monhdr; 139 list_add_tail(&monbuf->list, &monpriv->list); 140 if (monhdr->mon_function != MONWRITE_GEN_EVENT) 141 mon_buf_count++; 142 } 143 monpriv->current_buf = monbuf; 144 return rc; 145 } 146 147 static int monwrite_new_data(struct mon_private *monpriv) 148 { 149 struct monwrite_hdr *monhdr = &monpriv->hdr; 150 struct mon_buf *monbuf = monpriv->current_buf; 151 int rc = 0; 152 153 switch (monhdr->mon_function) { 154 case MONWRITE_START_INTERVAL: 155 if (!monbuf->diag_done) { 156 rc = monwrite_diag(monhdr, monbuf->data, 157 APPLDATA_START_INTERVAL_REC); 158 monbuf->diag_done = 1; 159 } 160 break; 161 case MONWRITE_START_CONFIG: 162 if (!monbuf->diag_done) { 163 rc = monwrite_diag(monhdr, monbuf->data, 164 APPLDATA_START_CONFIG_REC); 165 monbuf->diag_done = 1; 166 } 167 break; 168 case MONWRITE_GEN_EVENT: 169 rc = monwrite_diag(monhdr, monbuf->data, 170 APPLDATA_GEN_EVENT_REC); 171 list_del(&monpriv->current_buf->list); 172 kfree(monpriv->current_buf->data); 173 kfree(monpriv->current_buf); 174 monpriv->current_buf = NULL; 175 break; 176 default: 177 /* monhdr->mon_function is checked in monwrite_new_hdr */ 178 BUG(); 179 } 180 return rc; 181 } 182 183 /* 184 * file operations 185 */ 186 187 static int monwrite_open(struct inode *inode, struct file *filp) 188 { 189 struct mon_private *monpriv; 190 191 monpriv = kzalloc(sizeof(struct mon_private), GFP_KERNEL); 192 if (!monpriv) 193 return -ENOMEM; 194 INIT_LIST_HEAD(&monpriv->list); 195 monpriv->hdr_to_read = sizeof(monpriv->hdr); 196 mutex_init(&monpriv->thread_mutex); 197 filp->private_data = monpriv; 198 return nonseekable_open(inode, filp); 199 } 200 201 static int monwrite_close(struct inode *inode, struct file *filp) 202 { 203 struct mon_private *monpriv = filp->private_data; 204 struct mon_buf *entry, *next; 205 206 list_for_each_entry_safe(entry, next, &monpriv->list, list) { 207 if (entry->hdr.mon_function != MONWRITE_GEN_EVENT) 208 monwrite_diag(&entry->hdr, entry->data, 209 APPLDATA_STOP_REC); 210 mon_buf_count--; 211 list_del(&entry->list); 212 kfree(entry->data); 213 kfree(entry); 214 } 215 kfree(monpriv); 216 return 0; 217 } 218 219 static ssize_t monwrite_write(struct file *filp, const char __user *data, 220 size_t count, loff_t *ppos) 221 { 222 struct mon_private *monpriv = filp->private_data; 223 size_t len, written; 224 void *to; 225 int rc; 226 227 mutex_lock(&monpriv->thread_mutex); 228 for (written = 0; written < count; ) { 229 if (monpriv->hdr_to_read) { 230 len = min(count - written, monpriv->hdr_to_read); 231 to = (char *) &monpriv->hdr + 232 sizeof(monpriv->hdr) - monpriv->hdr_to_read; 233 if (copy_from_user(to, data + written, len)) { 234 rc = -EFAULT; 235 goto out_error; 236 } 237 monpriv->hdr_to_read -= len; 238 written += len; 239 if (monpriv->hdr_to_read > 0) 240 continue; 241 rc = monwrite_new_hdr(monpriv); 242 if (rc) 243 goto out_error; 244 monpriv->data_to_read = monpriv->current_buf ? 245 monpriv->current_buf->hdr.datalen : 0; 246 } 247 248 if (monpriv->data_to_read) { 249 len = min(count - written, monpriv->data_to_read); 250 to = monpriv->current_buf->data + 251 monpriv->hdr.datalen - monpriv->data_to_read; 252 if (copy_from_user(to, data + written, len)) { 253 rc = -EFAULT; 254 goto out_error; 255 } 256 monpriv->data_to_read -= len; 257 written += len; 258 if (monpriv->data_to_read > 0) 259 continue; 260 rc = monwrite_new_data(monpriv); 261 if (rc) 262 goto out_error; 263 } 264 monpriv->hdr_to_read = sizeof(monpriv->hdr); 265 } 266 mutex_unlock(&monpriv->thread_mutex); 267 return written; 268 269 out_error: 270 monpriv->data_to_read = 0; 271 monpriv->hdr_to_read = sizeof(struct monwrite_hdr); 272 mutex_unlock(&monpriv->thread_mutex); 273 return rc; 274 } 275 276 static const struct file_operations monwrite_fops = { 277 .owner = THIS_MODULE, 278 .open = &monwrite_open, 279 .release = &monwrite_close, 280 .write = &monwrite_write, 281 .llseek = noop_llseek, 282 }; 283 284 static struct miscdevice mon_dev = { 285 .name = "monwriter", 286 .fops = &monwrite_fops, 287 .minor = MISC_DYNAMIC_MINOR, 288 }; 289 290 /* 291 * module init/exit 292 */ 293 294 static int __init mon_init(void) 295 { 296 if (!MACHINE_IS_VM) 297 return -ENODEV; 298 /* 299 * misc_register() has to be the last action in module_init(), because 300 * file operations will be available right after this. 301 */ 302 return misc_register(&mon_dev); 303 } 304 305 static void __exit mon_exit(void) 306 { 307 misc_deregister(&mon_dev); 308 } 309 310 module_init(mon_init); 311 module_exit(mon_exit); 312 313 module_param_named(max_bufs, mon_max_bufs, int, 0644); 314 MODULE_PARM_DESC(max_bufs, "Maximum number of sample monitor data buffers " 315 "that can be active at one time"); 316 317 MODULE_AUTHOR("Melissa Howland <Melissa.Howland@us.ibm.com>"); 318 MODULE_DESCRIPTION("Character device driver for writing z/VM " 319 "APPLDATA monitor records."); 320 MODULE_LICENSE("GPL"); 321