fs/pstore/ram.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/pstore_ram.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 static int ramoops_ecc;
  60 module_param_named(ecc, ramoops_ecc, int, 0600);
  61 MODULE_PARM_DESC(ramoops_ecc,
  62                 "set to 1 to enable ECC support");
  63
  64 struct ramoops_context {
  65         struct persistent_ram_zone **przs;
  66         phys_addr_t phys_addr;
  67         unsigned long size;
  68         size_t record_size;
  69         int dump_oops;
  70         bool ecc;
  71         unsigned int count;
  72         unsigned int max_count;
  73         unsigned int read_count;
  74         struct pstore_info pstore;
  75 };
  76
  77 static struct platform_device *dummy;
  78 static struct ramoops_platform_data *dummy_data;
  79
  80 static int ramoops_pstore_open(struct pstore_info *psi)
  81 {
  82         struct ramoops_context *cxt = psi->data;
  83
  84         cxt->read_count = 0;
  85         return 0;
  86 }
  87
  88 static ssize_t ramoops_pstore_read(u64 *id, enum pstore_type_id *type,
  89                                    struct timespec *time,
  90                                    char **buf,
  91                                    struct pstore_info *psi)
  92 {
  93         ssize_t size;
  94         struct ramoops_context *cxt = psi->data;
  95         struct persistent_ram_zone *prz;
  96
  97         if (cxt->read_count >= cxt->max_count)
  98                 return -EINVAL;
  99
 100         *id = cxt->read_count++;
 101         prz = cxt->przs[*id];
 102
 103         /* Only supports dmesg output so far. */
 104         *type = PSTORE_TYPE_DMESG;
 105         /* TODO(kees): Bogus time for the moment. */
 106         time->tv_sec = 0;
 107         time->tv_nsec = 0;
 108
 109         /* Update old/shadowed buffer. */
 110         persistent_ram_save_old(prz);
 111         size = persistent_ram_old_size(prz);
 112         *buf = kmalloc(size, GFP_KERNEL);
 113         if (*buf == NULL)
 114                 return -ENOMEM;
 115         memcpy(*buf, persistent_ram_old(prz), size);
 116
 117         return size;
 118 }
 119
 120 static size_t ramoops_write_kmsg_hdr(struct persistent_ram_zone *prz)
 121 {
 122         char *hdr;
 123         struct timeval timestamp;
 124         size_t len;
 125
 126         do_gettimeofday(&timestamp);
 127         hdr = kasprintf(GFP_ATOMIC, RAMOOPS_KERNMSG_HDR "%lu.%lu\n",
 128                 (long)timestamp.tv_sec, (long)timestamp.tv_usec);
 129         WARN_ON_ONCE(!hdr);
 130         len = hdr ? strlen(hdr) : 0;
 131         persistent_ram_write(prz, hdr, len);
 132         kfree(hdr);
 133
 134         return len;
 135 }
 136
 137 static int ramoops_pstore_write(enum pstore_type_id type,
 138                                 enum kmsg_dump_reason reason,
 139                                 u64 *id,
 140                                 unsigned int part,
 141                                 size_t size, struct pstore_info *psi)
 142 {
 143         struct ramoops_context *cxt = psi->data;
 144         struct persistent_ram_zone *prz = cxt->przs[cxt->count];
 145         size_t hlen;
 146
 147         /* Currently ramoops is designed to only store dmesg dumps. */
 148         if (type != PSTORE_TYPE_DMESG)
 149                 return -EINVAL;
 150
 151         /* Out of the various dmesg dump types, ramoops is currently designed
 152          * to only store crash logs, rather than storing general kernel logs.
 153          */
 154         if (reason != KMSG_DUMP_OOPS &&
 155             reason != KMSG_DUMP_PANIC)
 156                 return -EINVAL;
 157
 158         /* Skip Oopes when configured to do so. */
 159         if (reason == KMSG_DUMP_OOPS && !cxt->dump_oops)
 160                 return -EINVAL;
 161
 162         /* Explicitly only take the first part of any new crash.
 163          * If our buffer is larger than kmsg_bytes, this can never happen,
 164          * and if our buffer is smaller than kmsg_bytes, we don't want the
 165          * report split across multiple records.
 166          */
 167         if (part != 1)
 168                 return -ENOSPC;
 169
 170         hlen = ramoops_write_kmsg_hdr(prz);
 171         if (size + hlen > prz->buffer_size)
 172                 size = prz->buffer_size - hlen;
 173         persistent_ram_write(prz, cxt->pstore.buf, size);
 174
 175         cxt->count = (cxt->count + 1) % cxt->max_count;
 176
 177         return 0;
 178 }
 179
 180 static int ramoops_pstore_erase(enum pstore_type_id type, u64 id,
 181                                 struct pstore_info *psi)
 182 {
 183         struct ramoops_context *cxt = psi->data;
 184
 185         if (id >= cxt->max_count)
 186                 return -EINVAL;
 187
 188         persistent_ram_free_old(cxt->przs[id]);
 189         persistent_ram_zap(cxt->przs[id]);
 190
 191         return 0;
 192 }
 193
 194 static struct ramoops_context oops_cxt = {
 195         .pstore = {
 196                 .owner  = THIS_MODULE,
 197                 .name   = "ramoops",
 198                 .open   = ramoops_pstore_open,
 199                 .read   = ramoops_pstore_read,
 200                 .write  = ramoops_pstore_write,
 201                 .erase  = ramoops_pstore_erase,
 202         },
 203 };
 204
 205 static int __init ramoops_probe(struct platform_device *pdev)
 206 {
 207         struct device *dev = &pdev->dev;
 208         struct ramoops_platform_data *pdata = pdev->dev.platform_data;
 209         struct ramoops_context *cxt = &oops_cxt;
 210         int err = -EINVAL;
 211         int i;
 212
 213         /* Only a single ramoops area allowed at a time, so fail extra
 214          * probes.
 215          */
 216         if (cxt->max_count)
 217                 goto fail_out;
 218
 219         if (!pdata->mem_size || !pdata->record_size) {
 220                 pr_err("The memory size and the record size must be "
 221                         "non-zero\n");
 222                 goto fail_out;
 223         }
 224
 225         pdata->mem_size = rounddown_pow_of_two(pdata->mem_size);
 226         pdata->record_size = rounddown_pow_of_two(pdata->record_size);
 227
 228         /* Check for the minimum memory size */
 229         if (pdata->mem_size < MIN_MEM_SIZE &&
 230                         pdata->record_size < MIN_MEM_SIZE) {
 231                 pr_err("memory size too small, minimum is %lu\n",
 232                         MIN_MEM_SIZE);
 233                 goto fail_out;
 234         }
 235
 236         if (pdata->mem_size < pdata->record_size) {
 237                 pr_err("The memory size must be larger than the "
 238                         "records size\n");
 239                 goto fail_out;
 240         }
 241
 242         cxt->max_count = pdata->mem_size / pdata->record_size;
 243         cxt->count = 0;
 244         cxt->size = pdata->mem_size;
 245         cxt->phys_addr = pdata->mem_address;
 246         cxt->record_size = pdata->record_size;
 247         cxt->dump_oops = pdata->dump_oops;
 248         cxt->ecc = pdata->ecc;
 249
 250         cxt->przs = kzalloc(sizeof(*cxt->przs) * cxt->max_count, GFP_KERNEL);
 251         if (!cxt->przs) {
 252                 err = -ENOMEM;
 253                 dev_err(dev, "failed to initialize a prz array\n");
 254                 goto fail_out;
 255         }
 256
 257         for (i = 0; i < cxt->max_count; i++) {
 258                 size_t sz = cxt->record_size;
 259                 phys_addr_t start = cxt->phys_addr + sz * i;
 260
 261                 cxt->przs[i] = persistent_ram_new(start, sz, cxt->ecc);
 262                 if (IS_ERR(cxt->przs[i])) {
 263                         err = PTR_ERR(cxt->przs[i]);
 264                         dev_err(dev, "failed to request mem region (0x%zx@0x%llx): %d\n",
 265                                 sz, (unsigned long long)start, err);
 266                         goto fail_przs;
 267                 }
 268         }
 269
 270         cxt->pstore.data = cxt;
 271         cxt->pstore.bufsize = cxt->przs[0]->buffer_size;
 272         cxt->pstore.buf = kmalloc(cxt->pstore.bufsize, GFP_KERNEL);
 273         spin_lock_init(&cxt->pstore.buf_lock);
 274         if (!cxt->pstore.buf) {
 275                 pr_err("cannot allocate pstore buffer\n");
 276                 goto fail_clear;
 277         }
 278
 279         err = pstore_register(&cxt->pstore);
 280         if (err) {
 281                 pr_err("registering with pstore failed\n");
 282                 goto fail_buf;
 283         }
 284
 285         /*
 286          * Update the module parameter variables as well so they are visible
 287          * through /sys/module/ramoops/parameters/
 288          */
 289         mem_size = pdata->mem_size;
 290         mem_address = pdata->mem_address;
 291         record_size = pdata->record_size;
 292         dump_oops = pdata->dump_oops;
 293
 294         pr_info("attached 0x%lx@0x%llx (%ux0x%zx), ecc: %s\n",
 295                 cxt->size, (unsigned long long)cxt->phys_addr,
 296                 cxt->max_count, cxt->record_size,
 297                 ramoops_ecc ? "on" : "off");
 298
 299         return 0;
 300
 301 fail_buf:
 302         kfree(cxt->pstore.buf);
 303 fail_clear:
 304         cxt->pstore.bufsize = 0;
 305         cxt->max_count = 0;
 306 fail_przs:
 307         for (i = 0; cxt->przs[i]; i++)
 308                 persistent_ram_free(cxt->przs[i]);
 309         kfree(cxt->przs);
 310 fail_out:
 311         return err;
 312 }
 313
 314 static int __exit ramoops_remove(struct platform_device *pdev)
 315 {
 316 #if 0
 317         /* TODO(kees): We cannot unload ramoops since pstore doesn't support
 318          * unregistering yet.
 319          */
 320         struct ramoops_context *cxt = &oops_cxt;
 321
 322         iounmap(cxt->virt_addr);
 323         release_mem_region(cxt->phys_addr, cxt->size);
 324         cxt->max_count = 0;
 325
 326         /* TODO(kees): When pstore supports unregistering, call it here. */
 327         kfree(cxt->pstore.buf);
 328         cxt->pstore.bufsize = 0;
 329
 330         return 0;
 331 #endif
 332         return -EBUSY;
 333 }
 334
 335 static struct platform_driver ramoops_driver = {
 336         .remove         = __exit_p(ramoops_remove),
 337         .driver         = {
 338                 .name   = "ramoops",
 339                 .owner  = THIS_MODULE,
 340         },
 341 };
 342
 343 static int __init ramoops_init(void)
 344 {
 345         int ret;
 346         ret = platform_driver_probe(&ramoops_driver, ramoops_probe);
 347         if (ret == -ENODEV) {
 348                 /*
 349                  * If we didn't find a platform device, we use module parameters
 350                  * building platform data on the fly.
 351                  */
 352                 pr_info("platform device not found, using module parameters\n");
 353                 dummy_data = kzalloc(sizeof(struct ramoops_platform_data),
 354                                      GFP_KERNEL);
 355                 if (!dummy_data)
 356                         return -ENOMEM;
 357                 dummy_data->mem_size = mem_size;
 358                 dummy_data->mem_address = mem_address;
 359                 dummy_data->record_size = record_size;
 360                 dummy_data->dump_oops = dump_oops;
 361                 dummy_data->ecc = ramoops_ecc;
 362                 dummy = platform_create_bundle(&ramoops_driver, ramoops_probe,
 363                         NULL, 0, dummy_data,
 364                         sizeof(struct ramoops_platform_data));
 365
 366                 if (IS_ERR(dummy))
 367                         ret = PTR_ERR(dummy);
 368                 else
 369                         ret = 0;
 370         }
 371
 372         return ret;
 373 }
 374
 375 static void __exit ramoops_exit(void)
 376 {
 377         platform_driver_unregister(&ramoops_driver);
 378         kfree(dummy_data);
 379 }
 380
 381 module_init(ramoops_init);
 382 module_exit(ramoops_exit);
 383
 384 MODULE_LICENSE("GPL");
 385 MODULE_AUTHOR("Marco Stornelli <marco.stornelli@gmail.com>");
 386 MODULE_DESCRIPTION("RAM Oops/Panic logger/driver");