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/module.h>
  26 #include <linux/kmsg_dump.h>
  27 #include <linux/time.h>
  28 #include <linux/io.h>
  29 #include <linux/ioport.h>
  30 #include <linux/platform_device.h>
  31 #include <linux/slab.h>
  32 #include <linux/ramoops.h>
  33
  34 #define RAMOOPS_KERNMSG_HDR "===="
  35
  36 #define RECORD_SIZE 4096UL
  37
  38 static ulong mem_address;
  39 module_param(mem_address, ulong, 0400);
  40 MODULE_PARM_DESC(mem_address,
  41                 "start of reserved RAM used to store oops/panic logs");
  42
  43 static ulong mem_size;
  44 module_param(mem_size, ulong, 0400);
  45 MODULE_PARM_DESC(mem_size,
  46                 "size of reserved RAM used to store oops/panic logs");
  47
  48 static int dump_oops = 1;
  49 module_param(dump_oops, int, 0600);
  50 MODULE_PARM_DESC(dump_oops,
  51                 "set to 1 to dump oopses, 0 to only dump panics (default 1)");
  52
  53 static struct ramoops_context {
  54         struct kmsg_dumper dump;
  55         void *virt_addr;
  56         phys_addr_t phys_addr;
  57         unsigned long size;
  58         int dump_oops;
  59         int count;
  60         int max_count;
  61 } oops_cxt;
  62
  63 static struct platform_device *dummy;
  64 static struct ramoops_platform_data *dummy_data;
  65
  66 static void ramoops_do_dump(struct kmsg_dumper *dumper,
  67                 enum kmsg_dump_reason reason, const char *s1, unsigned long l1,
  68                 const char *s2, unsigned long l2)
  69 {
  70         struct ramoops_context *cxt = container_of(dumper,
  71                         struct ramoops_context, dump);
  72         unsigned long s1_start, s2_start;
  73         unsigned long l1_cpy, l2_cpy;
  74         int res, hdr_size;
  75         char *buf, *buf_orig;
  76         struct timeval timestamp;
  77
  78         if (reason != KMSG_DUMP_OOPS &&
  79             reason != KMSG_DUMP_PANIC &&
  80             reason != KMSG_DUMP_KEXEC)
  81                 return;
  82
  83         /* Only dump oopses if dump_oops is set */
  84         if (reason == KMSG_DUMP_OOPS && !cxt->dump_oops)
  85                 return;
  86
  87         buf = cxt->virt_addr + (cxt->count * RECORD_SIZE);
  88         buf_orig = buf;
  89
  90         memset(buf, '\0', RECORD_SIZE);
  91         res = sprintf(buf, "%s", RAMOOPS_KERNMSG_HDR);
  92         buf += res;
  93         do_gettimeofday(&timestamp);
  94         res = sprintf(buf, "%lu.%lu\n", (long)timestamp.tv_sec, (long)timestamp.tv_usec);
  95         buf += res;
  96
  97         hdr_size = buf - buf_orig;
  98         l2_cpy = min(l2, RECORD_SIZE - hdr_size);
  99         l1_cpy = min(l1, RECORD_SIZE - hdr_size - l2_cpy);
 100
 101         s2_start = l2 - l2_cpy;
 102         s1_start = l1 - l1_cpy;
 103
 104         memcpy(buf, s1 + s1_start, l1_cpy);
 105         memcpy(buf + l1_cpy, s2 + s2_start, l2_cpy);
 106
 107         cxt->count = (cxt->count + 1) % cxt->max_count;
 108 }
 109
 110 static int __init ramoops_probe(struct platform_device *pdev)
 111 {
 112         struct ramoops_platform_data *pdata = pdev->dev.platform_data;
 113         struct ramoops_context *cxt = &oops_cxt;
 114         int err = -EINVAL;
 115
 116         if (!pdata->mem_size) {
 117                 pr_err("invalid size specification\n");
 118                 goto fail3;
 119         }
 120
 121         rounddown_pow_of_two(pdata->mem_size);
 122
 123         if (pdata->mem_size < RECORD_SIZE) {
 124                 pr_err("size too small\n");
 125                 goto fail3;
 126         }
 127
 128         cxt->max_count = pdata->mem_size / RECORD_SIZE;
 129         cxt->count = 0;
 130         cxt->size = pdata->mem_size;
 131         cxt->phys_addr = pdata->mem_address;
 132         cxt->dump_oops = pdata->dump_oops;
 133
 134         if (!request_mem_region(cxt->phys_addr, cxt->size, "ramoops")) {
 135                 pr_err("request mem region failed\n");
 136                 err = -EINVAL;
 137                 goto fail3;
 138         }
 139
 140         cxt->virt_addr = ioremap(cxt->phys_addr,  cxt->size);
 141         if (!cxt->virt_addr) {
 142                 pr_err("ioremap failed\n");
 143                 goto fail2;
 144         }
 145
 146         cxt->dump.dump = ramoops_do_dump;
 147         err = kmsg_dump_register(&cxt->dump);
 148         if (err) {
 149                 pr_err("registering kmsg dumper failed\n");
 150                 goto fail1;
 151         }
 152
 153         return 0;
 154
 155 fail1:
 156         iounmap(cxt->virt_addr);
 157 fail2:
 158         release_mem_region(cxt->phys_addr, cxt->size);
 159 fail3:
 160         return err;
 161 }
 162
 163 static int __exit ramoops_remove(struct platform_device *pdev)
 164 {
 165         struct ramoops_context *cxt = &oops_cxt;
 166
 167         if (kmsg_dump_unregister(&cxt->dump) < 0)
 168                 pr_warn("could not unregister kmsg_dumper\n");
 169
 170         iounmap(cxt->virt_addr);
 171         release_mem_region(cxt->phys_addr, cxt->size);
 172         return 0;
 173 }
 174
 175 static struct platform_driver ramoops_driver = {
 176         .remove         = __exit_p(ramoops_remove),
 177         .driver         = {
 178                 .name   = "ramoops",
 179                 .owner  = THIS_MODULE,
 180         },
 181 };
 182
 183 static int __init ramoops_init(void)
 184 {
 185         int ret;
 186         ret = platform_driver_probe(&ramoops_driver, ramoops_probe);
 187         if (ret == -ENODEV) {
 188                 /*
 189                  * If we didn't find a platform device, we use module parameters
 190                  * building platform data on the fly.
 191                  */
 192                 pr_info("platform device not found, using module parameters\n");
 193                 dummy_data = kzalloc(sizeof(struct ramoops_platform_data),
 194                                      GFP_KERNEL);
 195                 if (!dummy_data)
 196                         return -ENOMEM;
 197                 dummy_data->mem_size = mem_size;
 198                 dummy_data->mem_address = mem_address;
 199                 dummy_data->dump_oops = dump_oops;
 200                 dummy = platform_create_bundle(&ramoops_driver, ramoops_probe,
 201                         NULL, 0, dummy_data,
 202                         sizeof(struct ramoops_platform_data));
 203
 204                 if (IS_ERR(dummy))
 205                         ret = PTR_ERR(dummy);
 206                 else
 207                         ret = 0;
 208         }
 209
 210         return ret;
 211 }
 212
 213 static void __exit ramoops_exit(void)
 214 {
 215         platform_driver_unregister(&ramoops_driver);
 216         kfree(dummy_data);
 217 }
 218
 219 module_init(ramoops_init);
 220 module_exit(ramoops_exit);
 221
 222 MODULE_LICENSE("GPL");
 223 MODULE_AUTHOR("Marco Stornelli <marco.stornelli@gmail.com>");
 224 MODULE_DESCRIPTION("RAM Oops/Panic logger/driver");