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
  33 #define RECORD_SIZE 4096
  34
  35 static ulong mem_address;
  36 module_param(mem_address, ulong, 0400);
  37 MODULE_PARM_DESC(mem_address,
  38                 "start of reserved RAM used to store oops/panic logs");
  39
  40 static ulong mem_size;
  41 module_param(mem_size, ulong, 0400);
  42 MODULE_PARM_DESC(mem_size,
  43                 "size of reserved RAM used to store oops/panic logs");
  44
  45 static int dump_oops = 1;
  46 module_param(dump_oops, int, 0600);
  47 MODULE_PARM_DESC(dump_oops,
  48                 "set to 1 to dump oopses, 0 to only dump panics (default 1)");
  49
  50 static struct ramoops_context {
  51         struct kmsg_dumper dump;
  52         void *virt_addr;
  53         phys_addr_t phys_addr;
  54         unsigned long size;
  55         int count;
  56         int max_count;
  57         void (*enable)(int enable);
  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, hdr_size;
  69         char *buf, *buf_orig;
  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         if (cxt->enable)
  77                 cxt->enable(true);
  78
  79         buf = (char *)(cxt->virt_addr + (cxt->count * RECORD_SIZE));
  80         buf_orig = buf;
  81
  82         memset(buf, '\0', RECORD_SIZE);
  83         res = sprintf(buf, "%s", RAMOOPS_KERNMSG_HDR);
  84         buf += res;
  85         do_gettimeofday(&timestamp);
  86         res = sprintf(buf, "%lu.%lu\n", (long)timestamp.tv_sec, (long)timestamp.tv_usec);
  87         buf += res;
  88
  89         hdr_size = buf - buf_orig;
  90         l2_cpy = min(l2, (unsigned long)(RECORD_SIZE - hdr_size));
  91         l1_cpy = min(l1, (unsigned long)(RECORD_SIZE - hdr_size) - l2_cpy);
  92
  93         s2_start = l2 - l2_cpy;
  94         s1_start = l1 - l1_cpy;
  95
  96         memcpy(buf, s1 + s1_start, l1_cpy);
  97         memcpy(buf + l1_cpy, s2 + s2_start, l2_cpy);
  98
  99         cxt->count = (cxt->count + 1) % cxt->max_count;
 100
 101         if (cxt->enable)
 102                 cxt->enable(false);
 103 }
 104
 105 static int __init ramoops_probe(struct platform_device *pdev)
 106 {
 107         struct ramoops_platform_data *pdata = pdev->dev.platform_data;
 108         struct ramoops_context *cxt = &oops_cxt;
 109         int err = -EINVAL;
 110
 111         if (pdata) {
 112                 mem_size = pdata->mem_size;
 113                 mem_address = pdata->mem_address;
 114                 if (pdata->enable)
 115                         cxt->enable = pdata->enable;
 116         }
 117
 118         if (!mem_size) {
 119                 printk(KERN_ERR "ramoops: invalid size specification");
 120                 goto fail3;
 121         }
 122
 123         rounddown_pow_of_two(mem_size);
 124
 125         if (mem_size < RECORD_SIZE) {
 126                 printk(KERN_ERR "ramoops: size too small");
 127                 goto fail3;
 128         }
 129
 130         cxt->max_count = mem_size / RECORD_SIZE;
 131         cxt->count = 0;
 132         cxt->size = mem_size;
 133         cxt->phys_addr = mem_address;
 134
 135         if (!request_mem_region(cxt->phys_addr, cxt->size, "ramoops")) {
 136                 printk(KERN_ERR "ramoops: request mem region failed");
 137                 err = -EINVAL;
 138                 goto fail3;
 139         }
 140
 141         cxt->virt_addr = ioremap(cxt->phys_addr,  cxt->size);
 142         if (!cxt->virt_addr) {
 143                 printk(KERN_ERR "ramoops: ioremap failed");
 144                 goto fail2;
 145         }
 146
 147         cxt->dump.dump = ramoops_do_dump;
 148         err = kmsg_dump_register(&cxt->dump);
 149         if (err) {
 150                 printk(KERN_ERR "ramoops: registering kmsg dumper failed");
 151                 goto fail1;
 152         }
 153
 154         return 0;
 155
 156 fail1:
 157         iounmap(cxt->virt_addr);
 158 fail2:
 159         release_mem_region(cxt->phys_addr, cxt->size);
 160 fail3:
 161         return err;
 162 }
 163
 164 static int __exit ramoops_remove(struct platform_device *pdev)
 165 {
 166         struct ramoops_context *cxt = &oops_cxt;
 167
 168         if (kmsg_dump_unregister(&cxt->dump) < 0)
 169                 printk(KERN_WARNING "ramoops: could not unregister kmsg_dumper");
 170
 171         iounmap(cxt->virt_addr);
 172         release_mem_region(cxt->phys_addr, cxt->size);
 173         return 0;
 174 }
 175
 176 static struct platform_driver ramoops_driver = {
 177         .remove                 = __exit_p(ramoops_remove),
 178         .driver                 = {
 179                 .name           = "ramoops",
 180                 .owner          = THIS_MODULE,
 181         },
 182 };
 183
 184 static int __init ramoops_init(void)
 185 {
 186         return platform_driver_probe(&ramoops_driver, ramoops_probe);
 187 }
 188
 189 static void __exit ramoops_exit(void)
 190 {
 191         platform_driver_unregister(&ramoops_driver);
 192 }
 193
 194 module_init(ramoops_init);
 195 module_exit(ramoops_exit);
 196
 197 MODULE_LICENSE("GPL");
 198 MODULE_AUTHOR("Marco Stornelli <marco.stornelli@gmail.com>");
 199 MODULE_DESCRIPTION("RAM Oops/Panic logger/driver");