drivers/char/ramoops.c

   1 /*
   2  * RAM Oops/Panic logger
   3  *
   4  * Copyright (C) 2010 Marco Stornelli <marco.stornelli@gmail.com>
   5  * Copyright (C) 2011 Kees Cook <keescook@chromium.org>
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License
   9  * version 2 as published by the Free Software Foundation.
  10  *
  11  * This program is distributed in the hope that it will be useful, but
  12  * WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
  19  * 02110-1301 USA
  20  *
  21  */
  22
  23 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  24
  25 #include <linux/kernel.h>
  26 #include <linux/err.h>
  27 #include <linux/module.h>
  28 #include <linux/pstore.h>
  29 #include <linux/time.h>
  30 #include <linux/io.h>
  31 #include <linux/ioport.h>
  32 #include <linux/platform_device.h>
  33 #include <linux/slab.h>
  34 #include <linux/ramoops.h>
  35
  36 #define RAMOOPS_KERNMSG_HDR "===="
  37 #define MIN_MEM_SIZE 4096UL
  38
  39 static ulong record_size = MIN_MEM_SIZE;
  40 module_param(record_size, ulong, 0400);
  41 MODULE_PARM_DESC(record_size,
  42                 "size of each dump done on oops/panic");
  43
  44 static ulong mem_address;
  45 module_param(mem_address, ulong, 0400);
  46 MODULE_PARM_DESC(mem_address,
  47                 "start of reserved RAM used to store oops/panic logs");
  48
  49 static ulong mem_size;
  50 module_param(mem_size, ulong, 0400);
  51 MODULE_PARM_DESC(mem_size,
  52                 "size of reserved RAM used to store oops/panic logs");
  53
  54 static int dump_oops = 1;
  55 module_param(dump_oops, int, 0600);
  56 MODULE_PARM_DESC(dump_oops,
  57                 "set to 1 to dump oopses, 0 to only dump panics (default 1)");
  58
  59 struct ramoops_context {
  60         void *virt_addr;
  61         phys_addr_t phys_addr;
  62         unsigned long size;
  63         size_t record_size;
  64         int dump_oops;
  65         unsigned int count;
  66         unsigned int max_count;
  67         unsigned int read_count;
  68         struct pstore_info pstore;
  69 };
  70
  71 static struct platform_device *dummy;
  72 static struct ramoops_platform_data *dummy_data;
  73
  74 static int ramoops_pstore_open(struct pstore_info *psi)
  75 {
  76         struct ramoops_context *cxt = psi->data;
  77
  78         cxt->read_count = 0;
  79         return 0;
  80 }
  81
  82 static ssize_t ramoops_pstore_read(u64 *id, enum pstore_type_id *type,
  83                                    struct timespec *time,
  84                                    char **buf,
  85                                    struct pstore_info *psi)
  86 {
  87         ssize_t size;
  88         char *rambuf;
  89         struct ramoops_context *cxt = psi->data;
  90
  91         if (cxt->read_count >= cxt->max_count)
  92                 return -EINVAL;
  93         *id = cxt->read_count++;
  94         /* Only supports dmesg output so far. */
  95         *type = PSTORE_TYPE_DMESG;
  96         /* TODO(kees): Bogus time for the moment. */
  97         time->tv_sec = 0;
  98         time->tv_nsec = 0;
  99
 100         rambuf = cxt->virt_addr + (*id * cxt->record_size);
 101         size = strnlen(rambuf, cxt->record_size);
 102         *buf = kmalloc(size, GFP_KERNEL);
 103         if (*buf == NULL)
 104                 return -ENOMEM;
 105         memcpy(*buf, rambuf, size);
 106
 107         return size;
 108 }
 109
 110 static int ramoops_pstore_write(enum pstore_type_id type,
 111                                 enum kmsg_dump_reason reason,
 112                                 u64 *id,
 113                                 unsigned int part,
 114                                 size_t size, struct pstore_info *psi)
 115 {
 116         char *buf;
 117         size_t res;
 118         struct timeval timestamp;
 119         struct ramoops_context *cxt = psi->data;
 120         size_t available = cxt->record_size;
 121
 122         /* Currently ramoops is designed to only store dmesg dumps. */
 123         if (type != PSTORE_TYPE_DMESG)
 124                 return -EINVAL;
 125
 126         /* Out of the various dmesg dump types, ramoops is currently designed
 127          * to only store crash logs, rather than storing general kernel logs.
 128          */
 129         if (reason != KMSG_DUMP_OOPS &&
 130             reason != KMSG_DUMP_PANIC)
 131                 return -EINVAL;
 132
 133         /* Skip Oopes when configured to do so. */
 134         if (reason == KMSG_DUMP_OOPS && !cxt->dump_oops)
 135                 return -EINVAL;
 136
 137         /* Explicitly only take the first part of any new crash.
 138          * If our buffer is larger than kmsg_bytes, this can never happen,
 139          * and if our buffer is smaller than kmsg_bytes, we don't want the
 140          * report split across multiple records.
 141          */
 142         if (part != 1)
 143                 return -ENOSPC;
 144
 145         buf = cxt->virt_addr + (cxt->count * cxt->record_size);
 146
 147         res = sprintf(buf, "%s", RAMOOPS_KERNMSG_HDR);
 148         buf += res;
 149         available -= res;
 150
 151         do_gettimeofday(&timestamp);
 152         res = sprintf(buf, "%lu.%lu\n", (long)timestamp.tv_sec, (long)timestamp.tv_usec);
 153         buf += res;
 154         available -= res;
 155
 156         if (size > available)
 157                 size = available;
 158
 159         memcpy(buf, cxt->pstore.buf, size);
 160         memset(buf + size, '\0', available - size);
 161
 162         cxt->count = (cxt->count + 1) % cxt->max_count;
 163
 164         return 0;
 165 }
 166
 167 static int ramoops_pstore_erase(enum pstore_type_id type, u64 id,
 168                                 struct pstore_info *psi)
 169 {
 170         char *buf;
 171         struct ramoops_context *cxt = psi->data;
 172
 173         if (id >= cxt->max_count)
 174                 return -EINVAL;
 175
 176         buf = cxt->virt_addr + (id * cxt->record_size);
 177         memset(buf, '\0', cxt->record_size);
 178
 179         return 0;
 180 }
 181
 182 static struct ramoops_context oops_cxt = {
 183         .pstore = {
 184                 .owner  = THIS_MODULE,
 185                 .name   = "ramoops",
 186                 .open   = ramoops_pstore_open,
 187                 .read   = ramoops_pstore_read,
 188                 .write  = ramoops_pstore_write,
 189                 .erase  = ramoops_pstore_erase,
 190         },
 191 };
 192
 193 static int __init ramoops_probe(struct platform_device *pdev)
 194 {
 195         struct ramoops_platform_data *pdata = pdev->dev.platform_data;
 196         struct ramoops_context *cxt = &oops_cxt;
 197         int err = -EINVAL;
 198
 199         /* Only a single ramoops area allowed at a time, so fail extra
 200          * probes.
 201          */
 202         if (cxt->max_count)
 203                 goto fail_out;
 204
 205         if (!pdata->mem_size || !pdata->record_size) {
 206                 pr_err("The memory size and the record size must be "
 207                         "non-zero\n");
 208                 goto fail_out;
 209         }
 210
 211         pdata->mem_size = rounddown_pow_of_two(pdata->mem_size);
 212         pdata->record_size = rounddown_pow_of_two(pdata->record_size);
 213
 214         /* Check for the minimum memory size */
 215         if (pdata->mem_size < MIN_MEM_SIZE &&
 216                         pdata->record_size < MIN_MEM_SIZE) {
 217                 pr_err("memory size too small, minimum is %lu\n",
 218                         MIN_MEM_SIZE);
 219                 goto fail_out;
 220         }
 221
 222         if (pdata->mem_size < pdata->record_size) {
 223                 pr_err("The memory size must be larger than the "
 224                         "records size\n");
 225                 goto fail_out;
 226         }
 227
 228         cxt->max_count = pdata->mem_size / pdata->record_size;
 229         cxt->count = 0;
 230         cxt->size = pdata->mem_size;
 231         cxt->phys_addr = pdata->mem_address;
 232         cxt->record_size = pdata->record_size;
 233         cxt->dump_oops = pdata->dump_oops;
 234
 235         cxt->pstore.data = cxt;
 236         cxt->pstore.bufsize = cxt->record_size;
 237         cxt->pstore.buf = kmalloc(cxt->pstore.bufsize, GFP_KERNEL);
 238         spin_lock_init(&cxt->pstore.buf_lock);
 239         if (!cxt->pstore.buf) {
 240                 pr_err("cannot allocate pstore buffer\n");
 241                 goto fail_clear;
 242         }
 243
 244         if (!request_mem_region(cxt->phys_addr, cxt->size, "ramoops")) {
 245                 pr_err("request mem region (0x%lx@0x%llx) failed\n",
 246                         cxt->size, cxt->phys_addr);
 247                 err = -EINVAL;
 248                 goto fail_buf;
 249         }
 250
 251         cxt->virt_addr = ioremap(cxt->phys_addr,  cxt->size);
 252         if (!cxt->virt_addr) {
 253                 pr_err("ioremap failed\n");
 254                 goto fail_mem_region;
 255         }
 256
 257         err = pstore_register(&cxt->pstore);
 258         if (err) {
 259                 pr_err("registering with pstore failed\n");
 260                 goto fail_iounmap;
 261         }
 262
 263         /*
 264          * Update the module parameter variables as well so they are visible
 265          * through /sys/module/ramoops/parameters/
 266          */
 267         mem_size = pdata->mem_size;
 268         mem_address = pdata->mem_address;
 269         record_size = pdata->record_size;
 270         dump_oops = pdata->dump_oops;
 271
 272         pr_info("attached 0x%lx@0x%llx (%ux0x%zx)\n",
 273                 cxt->size, cxt->phys_addr, cxt->max_count, cxt->record_size);
 274
 275         return 0;
 276
 277 fail_iounmap:
 278         iounmap(cxt->virt_addr);
 279 fail_mem_region:
 280         release_mem_region(cxt->phys_addr, cxt->size);
 281 fail_buf:
 282         kfree(cxt->pstore.buf);
 283 fail_clear:
 284         cxt->pstore.bufsize = 0;
 285         cxt->max_count = 0;
 286 fail_out:
 287         return err;
 288 }
 289
 290 static int __exit ramoops_remove(struct platform_device *pdev)
 291 {
 292 #if 0
 293         /* TODO(kees): We cannot unload ramoops since pstore doesn't support
 294          * unregistering yet.
 295          */
 296         struct ramoops_context *cxt = &oops_cxt;
 297
 298         iounmap(cxt->virt_addr);
 299         release_mem_region(cxt->phys_addr, cxt->size);
 300         cxt->max_count = 0;
 301
 302         /* TODO(kees): When pstore supports unregistering, call it here. */
 303         kfree(cxt->pstore.buf);
 304         cxt->pstore.bufsize = 0;
 305
 306         return 0;
 307 #endif
 308         return -EBUSY;
 309 }
 310
 311 static struct platform_driver ramoops_driver = {
 312         .remove         = __exit_p(ramoops_remove),
 313         .driver         = {
 314                 .name   = "ramoops",
 315                 .owner  = THIS_MODULE,
 316         },
 317 };
 318
 319 static int __init ramoops_init(void)
 320 {
 321         int ret;
 322         ret = platform_driver_probe(&ramoops_driver, ramoops_probe);
 323         if (ret == -ENODEV) {
 324                 /*
 325                  * If we didn't find a platform device, we use module parameters
 326                  * building platform data on the fly.
 327                  */
 328                 pr_info("platform device not found, using module parameters\n");
 329                 dummy_data = kzalloc(sizeof(struct ramoops_platform_data),
 330                                      GFP_KERNEL);
 331                 if (!dummy_data)
 332                         return -ENOMEM;
 333                 dummy_data->mem_size = mem_size;
 334                 dummy_data->mem_address = mem_address;
 335                 dummy_data->record_size = record_size;
 336                 dummy_data->dump_oops = dump_oops;
 337                 dummy = platform_create_bundle(&ramoops_driver, ramoops_probe,
 338                         NULL, 0, dummy_data,
 339                         sizeof(struct ramoops_platform_data));
 340
 341                 if (IS_ERR(dummy))
 342                         ret = PTR_ERR(dummy);
 343                 else
 344                         ret = 0;
 345         }
 346
 347         return ret;
 348 }
 349
 350 static void __exit ramoops_exit(void)
 351 {
 352         platform_driver_unregister(&ramoops_driver);
 353         kfree(dummy_data);
 354 }
 355
 356 module_init(ramoops_init);
 357 module_exit(ramoops_exit);
 358
 359 MODULE_LICENSE("GPL");
 360 MODULE_AUTHOR("Marco Stornelli <marco.stornelli@gmail.com>");
 361 MODULE_DESCRIPTION("RAM Oops/Panic logger/driver");