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