drivers/char/ramoops.c

   1 /*
   2  * RAM Oops/Panic logger
   3  *
   4  * Copyright (C) 2010 Marco Stornelli <marco.stornelli@gmail.com>
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * version 2 as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
  18  * 02110-1301 USA
  19  *
  20  */
  21
  22 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  23
  24 #include <linux/kernel.h>
  25 #include <linux/err.h>
  26 #include <linux/module.h>
  27 #include <linux/kmsg_dump.h>
  28 #include <linux/time.h>
  29 #include <linux/io.h>
  30 #include <linux/ioport.h>
  31 #include <linux/platform_device.h>
  32 #include <linux/slab.h>
  33 #include <linux/ramoops.h>
  34
  35 #define RAMOOPS_KERNMSG_HDR "===="
  36 #define MIN_MEM_SIZE 4096UL
  37
  38 static ulong record_size = MIN_MEM_SIZE;
  39 module_param(record_size, ulong, 0400);
  40 MODULE_PARM_DESC(record_size,
  41                 "size of each dump done on oops/panic");
  42
  43 static ulong mem_address;
  44 module_param(mem_address, ulong, 0400);
  45 MODULE_PARM_DESC(mem_address,
  46                 "start of reserved RAM used to store oops/panic logs");
  47
  48 static ulong mem_size;
  49 module_param(mem_size, ulong, 0400);
  50 MODULE_PARM_DESC(mem_size,
  51                 "size of reserved RAM used to store oops/panic logs");
  52
  53 static int dump_oops = 1;
  54 module_param(dump_oops, int, 0600);
  55 MODULE_PARM_DESC(dump_oops,
  56                 "set to 1 to dump oopses, 0 to only dump panics (default 1)");
  57
  58 static struct ramoops_context {
  59         struct kmsg_dumper dump;
  60         void *virt_addr;
  61         phys_addr_t phys_addr;
  62         unsigned long size;
  63         unsigned long record_size;
  64         int dump_oops;
  65         int count;
  66         int max_count;
  67 } oops_cxt;
  68
  69 static struct platform_device *dummy;
  70 static struct ramoops_platform_data *dummy_data;
  71
  72 static void ramoops_do_dump(struct kmsg_dumper *dumper,
  73                 enum kmsg_dump_reason reason, const char *s1, unsigned long l1,
  74                 const char *s2, unsigned long l2)
  75 {
  76         struct ramoops_context *cxt = container_of(dumper,
  77                         struct ramoops_context, dump);
  78         unsigned long s1_start, s2_start;
  79         unsigned long l1_cpy, l2_cpy;
  80         int res, hdr_size;
  81         char *buf, *buf_orig;
  82         struct timeval timestamp;
  83
  84         if (reason != KMSG_DUMP_OOPS &&
  85             reason != KMSG_DUMP_PANIC &&
  86             reason != KMSG_DUMP_KEXEC)
  87                 return;
  88
  89         /* Only dump oopses if dump_oops is set */
  90         if (reason == KMSG_DUMP_OOPS && !cxt->dump_oops)
  91                 return;
  92
  93         buf = cxt->virt_addr + (cxt->count * cxt->record_size);
  94         buf_orig = buf;
  95
  96         memset(buf, '\0', cxt->record_size);
  97         res = sprintf(buf, "%s", RAMOOPS_KERNMSG_HDR);
  98         buf += res;
  99         do_gettimeofday(&timestamp);
 100         res = sprintf(buf, "%lu.%lu\n", (long)timestamp.tv_sec, (long)timestamp.tv_usec);
 101         buf += res;
 102
 103         hdr_size = buf - buf_orig;
 104         l2_cpy = min(l2, cxt->record_size - hdr_size);
 105         l1_cpy = min(l1, cxt->record_size - hdr_size - l2_cpy);
 106
 107         s2_start = l2 - l2_cpy;
 108         s1_start = l1 - l1_cpy;
 109
 110         memcpy(buf, s1 + s1_start, l1_cpy);
 111         memcpy(buf + l1_cpy, s2 + s2_start, l2_cpy);
 112
 113         cxt->count = (cxt->count + 1) % cxt->max_count;
 114 }
 115
 116 static int __init ramoops_probe(struct platform_device *pdev)
 117 {
 118         struct ramoops_platform_data *pdata = pdev->dev.platform_data;
 119         struct ramoops_context *cxt = &oops_cxt;
 120         int err = -EINVAL;
 121
 122         if (!pdata->mem_size || !pdata->record_size) {
 123                 pr_err("The memory size and the record size must be "
 124                         "non-zero\n");
 125                 goto fail3;
 126         }
 127
 128         rounddown_pow_of_two(pdata->mem_size);
 129         rounddown_pow_of_two(pdata->record_size);
 130
 131         /* Check for the minimum memory size */
 132         if (pdata->mem_size < MIN_MEM_SIZE &&
 133                         pdata->record_size < MIN_MEM_SIZE) {
 134                 pr_err("memory size too small, minium is %lu\n", MIN_MEM_SIZE);
 135                 goto fail3;
 136         }
 137
 138         if (pdata->mem_size < pdata->record_size) {
 139                 pr_err("The memory size must be larger than the "
 140                         "records size\n");
 141                 goto fail3;
 142         }
 143
 144         cxt->max_count = pdata->mem_size / pdata->record_size;
 145         cxt->count = 0;
 146         cxt->size = pdata->mem_size;
 147         cxt->phys_addr = pdata->mem_address;
 148         cxt->record_size = pdata->record_size;
 149         cxt->dump_oops = pdata->dump_oops;
 150         /*
 151          * Update the module parameter variables as well so they are visible
 152          * through /sys/module/ramoops/parameters/
 153          */
 154         mem_size = pdata->mem_size;
 155         mem_address = pdata->mem_address;
 156         record_size = pdata->record_size;
 157         dump_oops = pdata->dump_oops;
 158
 159         if (!request_mem_region(cxt->phys_addr, cxt->size, "ramoops")) {
 160                 pr_err("request mem region failed\n");
 161                 err = -EINVAL;
 162                 goto fail3;
 163         }
 164
 165         cxt->virt_addr = ioremap(cxt->phys_addr,  cxt->size);
 166         if (!cxt->virt_addr) {
 167                 pr_err("ioremap failed\n");
 168                 goto fail2;
 169         }
 170
 171         cxt->dump.dump = ramoops_do_dump;
 172         err = kmsg_dump_register(&cxt->dump);
 173         if (err) {
 174                 pr_err("registering kmsg dumper failed\n");
 175                 goto fail1;
 176         }
 177
 178         return 0;
 179
 180 fail1:
 181         iounmap(cxt->virt_addr);
 182 fail2:
 183         release_mem_region(cxt->phys_addr, cxt->size);
 184 fail3:
 185         return err;
 186 }
 187
 188 static int __exit ramoops_remove(struct platform_device *pdev)
 189 {
 190         struct ramoops_context *cxt = &oops_cxt;
 191
 192         if (kmsg_dump_unregister(&cxt->dump) < 0)
 193                 pr_warn("could not unregister kmsg_dumper\n");
 194
 195         iounmap(cxt->virt_addr);
 196         release_mem_region(cxt->phys_addr, cxt->size);
 197         return 0;
 198 }
 199
 200 static struct platform_driver ramoops_driver = {
 201         .remove         = __exit_p(ramoops_remove),
 202         .driver         = {
 203                 .name   = "ramoops",
 204                 .owner  = THIS_MODULE,
 205         },
 206 };
 207
 208 static int __init ramoops_init(void)
 209 {
 210         int ret;
 211         ret = platform_driver_probe(&ramoops_driver, ramoops_probe);
 212         if (ret == -ENODEV) {
 213                 /*
 214                  * If we didn't find a platform device, we use module parameters
 215                  * building platform data on the fly.
 216                  */
 217                 pr_info("platform device not found, using module parameters\n");
 218                 dummy_data = kzalloc(sizeof(struct ramoops_platform_data),
 219                                      GFP_KERNEL);
 220                 if (!dummy_data)
 221                         return -ENOMEM;
 222                 dummy_data->mem_size = mem_size;
 223                 dummy_data->mem_address = mem_address;
 224                 dummy_data->record_size = record_size;
 225                 dummy_data->dump_oops = dump_oops;
 226                 dummy = platform_create_bundle(&ramoops_driver, ramoops_probe,
 227                         NULL, 0, dummy_data,
 228                         sizeof(struct ramoops_platform_data));
 229
 230                 if (IS_ERR(dummy))
 231                         ret = PTR_ERR(dummy);
 232                 else
 233                         ret = 0;
 234         }
 235
 236         return ret;
 237 }
 238
 239 static void __exit ramoops_exit(void)
 240 {
 241         platform_driver_unregister(&ramoops_driver);
 242         kfree(dummy_data);
 243 }
 244
 245 module_init(ramoops_init);
 246 module_exit(ramoops_exit);
 247
 248 MODULE_LICENSE("GPL");
 249 MODULE_AUTHOR("Marco Stornelli <marco.stornelli@gmail.com>");
 250 MODULE_DESCRIPTION("RAM Oops/Panic logger/driver");