release/src-rt-6.x.4708/linux/linux-2.6.36/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
  31 #define RECORD_SIZE 4096
  32
  33 static ulong mem_address;
  34 module_param(mem_address, ulong, 0400);
  35 MODULE_PARM_DESC(mem_address,
  36                 "start of reserved RAM used to store oops/panic logs");
  37
  38 static ulong mem_size;
  39 module_param(mem_size, ulong, 0400);
  40 MODULE_PARM_DESC(mem_size,
  41                 "size of reserved RAM used to store oops/panic logs");
  42
  43 static int dump_oops = 1;
  44 module_param(dump_oops, int, 0600);
  45 MODULE_PARM_DESC(dump_oops,
  46                 "set to 1 to dump oopses, 0 to only dump panics (default 1)");
  47
  48 static struct ramoops_context {
  49         struct kmsg_dumper dump;
  50         void *virt_addr;
  51         phys_addr_t phys_addr;
  52         unsigned long size;
  53         int count;
  54         int max_count;
  55 } oops_cxt;
  56
  57 static void ramoops_do_dump(struct kmsg_dumper *dumper,
  58                 enum kmsg_dump_reason reason, const char *s1, unsigned long l1,
  59                 const char *s2, unsigned long l2)
  60 {
  61         struct ramoops_context *cxt = container_of(dumper,
  62                         struct ramoops_context, dump);
  63         unsigned long s1_start, s2_start;
  64         unsigned long l1_cpy, l2_cpy;
  65         int res, hdr_size;
  66         char *buf, *buf_orig;
  67         struct timeval timestamp;
  68
  69         /* Only dump oopses if dump_oops is set */
  70         if (reason == KMSG_DUMP_OOPS && !dump_oops)
  71                 return;
  72
  73         buf = (char *)(cxt->virt_addr + (cxt->count * RECORD_SIZE));
  74         buf_orig = buf;
  75
  76         memset(buf, '\0', RECORD_SIZE);
  77         res = sprintf(buf, "%s", RAMOOPS_KERNMSG_HDR);
  78         buf += res;
  79         do_gettimeofday(&timestamp);
  80         res = sprintf(buf, "%lu.%lu\n", (long)timestamp.tv_sec, (long)timestamp.tv_usec);
  81         buf += res;
  82
  83         hdr_size = buf - buf_orig;
  84         l2_cpy = min(l2, (unsigned long)(RECORD_SIZE - hdr_size));
  85         l1_cpy = min(l1, (unsigned long)(RECORD_SIZE - hdr_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_init(void)
  97 {
  98         struct ramoops_context *cxt = &oops_cxt;
  99         int err = -EINVAL;
 100
 101         if (!mem_size) {
 102                 printk(KERN_ERR "ramoops: invalid size specification");
 103                 goto fail3;
 104         }
 105
 106         rounddown_pow_of_two(mem_size);
 107
 108         if (mem_size < RECORD_SIZE) {
 109                 printk(KERN_ERR "ramoops: size too small");
 110                 goto fail3;
 111         }
 112
 113         cxt->max_count = mem_size / RECORD_SIZE;
 114         cxt->count = 0;
 115         cxt->size = mem_size;
 116         cxt->phys_addr = mem_address;
 117
 118         if (!request_mem_region(cxt->phys_addr, cxt->size, "ramoops")) {
 119                 printk(KERN_ERR "ramoops: request mem region failed");
 120                 err = -EINVAL;
 121                 goto fail3;
 122         }
 123
 124         cxt->virt_addr = ioremap(cxt->phys_addr,  cxt->size);
 125         if (!cxt->virt_addr) {
 126                 printk(KERN_ERR "ramoops: ioremap failed");
 127                 goto fail2;
 128         }
 129
 130         cxt->dump.dump = ramoops_do_dump;
 131         err = kmsg_dump_register(&cxt->dump);
 132         if (err) {
 133                 printk(KERN_ERR "ramoops: registering kmsg dumper failed");
 134                 goto fail1;
 135         }
 136
 137         return 0;
 138
 139 fail1:
 140         iounmap(cxt->virt_addr);
 141 fail2:
 142         release_mem_region(cxt->phys_addr, cxt->size);
 143 fail3:
 144         return err;
 145 }
 146
 147 static void __exit ramoops_exit(void)
 148 {
 149         struct ramoops_context *cxt = &oops_cxt;
 150
 151         if (kmsg_dump_unregister(&cxt->dump) < 0)
 152                 printk(KERN_WARNING "ramoops: could not unregister kmsg_dumper");
 153
 154         iounmap(cxt->virt_addr);
 155         release_mem_region(cxt->phys_addr, cxt->size);
 156 }
 157
 158
 159 module_init(ramoops_init);
 160 module_exit(ramoops_exit);
 161
 162 MODULE_LICENSE("GPL");
 163 MODULE_AUTHOR("Marco Stornelli <marco.stornelli@gmail.com>");
 164 MODULE_DESCRIPTION("RAM Oops/Panic logger/driver");