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 4096UL
  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 } oops_cxt;
  58
  59 static void ramoops_do_dump(struct kmsg_dumper *dumper,
  60                 enum kmsg_dump_reason reason, const char *s1, unsigned long l1,
  61                 const char *s2, unsigned long l2)
  62 {
  63         struct ramoops_context *cxt = container_of(dumper,
  64                         struct ramoops_context, dump);
  65         unsigned long s1_start, s2_start;
  66         unsigned long l1_cpy, l2_cpy;
  67         int res, hdr_size;
  68         char *buf, *buf_orig;
  69         struct timeval timestamp;
  70
  71         if (reason != KMSG_DUMP_OOPS &&
  72             reason != KMSG_DUMP_PANIC &&
  73             reason != KMSG_DUMP_KEXEC)
  74                 return;
  75
  76         /* Only dump oopses if dump_oops is set */
  77         if (reason == KMSG_DUMP_OOPS && !dump_oops)
  78                 return;
  79
  80         buf = cxt->virt_addr + (cxt->count * RECORD_SIZE);
  81         buf_orig = buf;
  82
  83         memset(buf, '\0', RECORD_SIZE);
  84         res = sprintf(buf, "%s", RAMOOPS_KERNMSG_HDR);
  85         buf += res;
  86         do_gettimeofday(&timestamp);
  87         res = sprintf(buf, "%lu.%lu\n", (long)timestamp.tv_sec, (long)timestamp.tv_usec);
  88         buf += res;
  89
  90         hdr_size = buf - buf_orig;
  91         l2_cpy = min(l2, RECORD_SIZE - hdr_size);
  92         l1_cpy = min(l1, RECORD_SIZE - hdr_size - l2_cpy);
  93
  94         s2_start = l2 - l2_cpy;
  95         s1_start = l1 - l1_cpy;
  96
  97         memcpy(buf, s1 + s1_start, l1_cpy);
  98         memcpy(buf + l1_cpy, s2 + s2_start, l2_cpy);
  99
 100         cxt->count = (cxt->count + 1) % cxt->max_count;
 101 }
 102
 103 static int __init ramoops_probe(struct platform_device *pdev)
 104 {
 105         struct ramoops_platform_data *pdata = pdev->dev.platform_data;
 106         struct ramoops_context *cxt = &oops_cxt;
 107         int err = -EINVAL;
 108
 109         if (pdata) {
 110                 mem_size = pdata->mem_size;
 111                 mem_address = pdata->mem_address;
 112         }
 113
 114         if (!mem_size) {
 115                 printk(KERN_ERR "ramoops: invalid size specification");
 116                 goto fail3;
 117         }
 118
 119         rounddown_pow_of_two(mem_size);
 120
 121         if (mem_size < RECORD_SIZE) {
 122                 printk(KERN_ERR "ramoops: size too small");
 123                 goto fail3;
 124         }
 125
 126         cxt->max_count = mem_size / RECORD_SIZE;
 127         cxt->count = 0;
 128         cxt->size = mem_size;
 129         cxt->phys_addr = mem_address;
 130
 131         if (!request_mem_region(cxt->phys_addr, cxt->size, "ramoops")) {
 132                 printk(KERN_ERR "ramoops: request mem region failed");
 133                 err = -EINVAL;
 134                 goto fail3;
 135         }
 136
 137         cxt->virt_addr = ioremap(cxt->phys_addr,  cxt->size);
 138         if (!cxt->virt_addr) {
 139                 printk(KERN_ERR "ramoops: ioremap failed");
 140                 goto fail2;
 141         }
 142
 143         cxt->dump.dump = ramoops_do_dump;
 144         err = kmsg_dump_register(&cxt->dump);
 145         if (err) {
 146                 printk(KERN_ERR "ramoops: registering kmsg dumper failed");
 147                 goto fail1;
 148         }
 149
 150         return 0;
 151
 152 fail1:
 153         iounmap(cxt->virt_addr);
 154 fail2:
 155         release_mem_region(cxt->phys_addr, cxt->size);
 156 fail3:
 157         return err;
 158 }
 159
 160 static int __exit ramoops_remove(struct platform_device *pdev)
 161 {
 162         struct ramoops_context *cxt = &oops_cxt;
 163
 164         if (kmsg_dump_unregister(&cxt->dump) < 0)
 165                 printk(KERN_WARNING "ramoops: could not unregister kmsg_dumper");
 166
 167         iounmap(cxt->virt_addr);
 168         release_mem_region(cxt->phys_addr, cxt->size);
 169         return 0;
 170 }
 171
 172 static struct platform_driver ramoops_driver = {
 173         .remove         = __exit_p(ramoops_remove),
 174         .driver         = {
 175                 .name   = "ramoops",
 176                 .owner  = THIS_MODULE,
 177         },
 178 };
 179
 180 static int __init ramoops_init(void)
 181 {
 182         return platform_driver_probe(&ramoops_driver, ramoops_probe);
 183 }
 184
 185 static void __exit ramoops_exit(void)
 186 {
 187         platform_driver_unregister(&ramoops_driver);
 188 }
 189
 190 module_init(ramoops_init);
 191 module_exit(ramoops_exit);
 192
 193 MODULE_LICENSE("GPL");
 194 MODULE_AUTHOR("Marco Stornelli <marco.stornelli@gmail.com>");
 195 MODULE_DESCRIPTION("RAM Oops/Panic logger/driver");