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