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 #include <linux/kernel.h>
  23 #include <linux/module.h>
  24 #include <linux/kmsg_dump.h>
  25 #include <linux/time.h>
  26 #include <linux/io.h>
  27 #include <linux/ioport.h>
  28 #include <linux/platform_device.h>
  29 #include <linux/ramoops.h>
  30
  31 #define RAMOOPS_KERNMSG_HDR "===="
  32 #define RAMOOPS_HEADER_SIZE   (5 + sizeof(struct timeval))
  33
  34 #define RECORD_SIZE 4096
  35
  36 static ulong mem_address;
  37 module_param(mem_address, ulong, 0400);
  38 MODULE_PARM_DESC(mem_address,
  39                 "start of reserved RAM used to store oops/panic logs");
  40
  41 static ulong mem_size;
  42 module_param(mem_size, ulong, 0400);
  43 MODULE_PARM_DESC(mem_size,
  44                 "size of reserved RAM used to store oops/panic logs");
  45
  46 static int dump_oops = 1;
  47 module_param(dump_oops, int, 0600);
  48 MODULE_PARM_DESC(dump_oops,
  49                 "set to 1 to dump oopses, 0 to only dump panics (default 1)");
  50
  51 static struct ramoops_context {
  52         struct kmsg_dumper dump;
  53         void *virt_addr;
  54         phys_addr_t phys_addr;
  55         unsigned long size;
  56         int count;
  57         int max_count;
  58 } oops_cxt;
  59
  60 static void ramoops_do_dump(struct kmsg_dumper *dumper,
  61                 enum kmsg_dump_reason reason, const char *s1, unsigned long l1,
  62                 const char *s2, unsigned long l2)
  63 {
  64         struct ramoops_context *cxt = container_of(dumper,
  65                         struct ramoops_context, dump);
  66         unsigned long s1_start, s2_start;
  67         unsigned long l1_cpy, l2_cpy;
  68         int res;
  69         char *buf;
  70         struct timeval timestamp;
  71
  72         /* Only dump oopses if dump_oops is set */
  73         if (reason == KMSG_DUMP_OOPS && !dump_oops)
  74                 return;
  75
  76         buf = (char *)(cxt->virt_addr + (cxt->count * RECORD_SIZE));
  77         memset(buf, '\0', RECORD_SIZE);
  78         res = sprintf(buf, "%s", RAMOOPS_KERNMSG_HDR);
  79         buf += res;
  80         do_gettimeofday(&timestamp);
  81         res = sprintf(buf, "%lu.%lu\n", (long)timestamp.tv_sec, (long)timestamp.tv_usec);
  82         buf += res;
  83
  84         l2_cpy = min(l2, (unsigned long)(RECORD_SIZE - RAMOOPS_HEADER_SIZE));
  85         l1_cpy = min(l1, (unsigned long)(RECORD_SIZE - RAMOOPS_HEADER_SIZE) - l2_cpy);
  86
  87         s2_start = l2 - l2_cpy;
  88         s1_start = l1 - l1_cpy;
  89
  90         memcpy(buf, s1 + s1_start, l1_cpy);
  91         memcpy(buf + l1_cpy, s2 + s2_start, l2_cpy);
  92
  93         cxt->count = (cxt->count + 1) % cxt->max_count;
  94 }
  95
  96 static int __init ramoops_probe(struct platform_device *pdev)
  97 {
  98         struct ramoops_platform_data *pdata = pdev->dev.platform_data;
  99         struct ramoops_context *cxt = &oops_cxt;
 100         int err = -EINVAL;
 101
 102         if (pdata) {
 103                 mem_size = pdata->mem_size;
 104                 mem_address = pdata->mem_address;
 105         }
 106
 107         if (!mem_size) {
 108                 printk(KERN_ERR "ramoops: invalid size specification");
 109                 goto fail3;
 110         }
 111
 112         rounddown_pow_of_two(mem_size);
 113
 114         if (mem_size < RECORD_SIZE) {
 115                 printk(KERN_ERR "ramoops: size too small");
 116                 goto fail3;
 117         }
 118
 119         cxt->max_count = mem_size / RECORD_SIZE;
 120         cxt->count = 0;
 121         cxt->size = mem_size;
 122         cxt->phys_addr = mem_address;
 123
 124         if (!request_mem_region(cxt->phys_addr, cxt->size, "ramoops")) {
 125                 printk(KERN_ERR "ramoops: request mem region failed");
 126                 err = -EINVAL;
 127                 goto fail3;
 128         }
 129
 130         cxt->virt_addr = ioremap(cxt->phys_addr,  cxt->size);
 131         if (!cxt->virt_addr) {
 132                 printk(KERN_ERR "ramoops: ioremap failed");
 133                 goto fail2;
 134         }
 135
 136         cxt->dump.dump = ramoops_do_dump;
 137         err = kmsg_dump_register(&cxt->dump);
 138         if (err) {
 139                 printk(KERN_ERR "ramoops: registering kmsg dumper failed");
 140                 goto fail1;
 141         }
 142
 143         return 0;
 144
 145 fail1:
 146         iounmap(cxt->virt_addr);
 147 fail2:
 148         release_mem_region(cxt->phys_addr, cxt->size);
 149 fail3:
 150         return err;
 151 }
 152
 153 static int __exit ramoops_remove(struct platform_device *pdev)
 154 {
 155         struct ramoops_context *cxt = &oops_cxt;
 156
 157         if (kmsg_dump_unregister(&cxt->dump) < 0)
 158                 printk(KERN_WARNING "ramoops: could not unregister kmsg_dumper");
 159
 160         iounmap(cxt->virt_addr);
 161         release_mem_region(cxt->phys_addr, cxt->size);
 162         return 0;
 163 }
 164
 165 static struct platform_driver ramoops_driver = {
 166         .remove         = __exit_p(ramoops_remove),
 167         .driver         = {
 168                 .name   = "ramoops",
 169                 .owner  = THIS_MODULE,
 170         },
 171 };
 172
 173 static int __init ramoops_init(void)
 174 {
 175         return platform_driver_probe(&ramoops_driver, ramoops_probe);
 176 }
 177
 178 static void __exit ramoops_exit(void)
 179 {
 180         platform_driver_unregister(&ramoops_driver);
 181 }
 182
 183 module_init(ramoops_init);
 184 module_exit(ramoops_exit);
 185
 186 MODULE_LICENSE("GPL");
 187 MODULE_AUTHOR("Marco Stornelli <marco.stornelli@gmail.com>");
 188 MODULE_DESCRIPTION("RAM Oops/Panic logger/driver");