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/slab.h>
  30 #include <linux/ramoops.h>
  31
  32 #define RAMOOPS_KERNMSG_HDR "===="
  33
  34 #define RECORD_SIZE 4096UL
  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 struct platform_device *dummy;
  61 static struct ramoops_platform_data *dummy_data;
  62
  63 static void ramoops_do_dump(struct kmsg_dumper *dumper,
  64                 enum kmsg_dump_reason reason, const char *s1, unsigned long l1,
  65                 const char *s2, unsigned long l2)
  66 {
  67         struct ramoops_context *cxt = container_of(dumper,
  68                         struct ramoops_context, dump);
  69         unsigned long s1_start, s2_start;
  70         unsigned long l1_cpy, l2_cpy;
  71         int res, hdr_size;
  72         char *buf, *buf_orig;
  73         struct timeval timestamp;
  74
  75         if (reason != KMSG_DUMP_OOPS &&
  76             reason != KMSG_DUMP_PANIC &&
  77             reason != KMSG_DUMP_KEXEC)
  78                 return;
  79
  80         /* Only dump oopses if dump_oops is set */
  81         if (reason == KMSG_DUMP_OOPS && !dump_oops)
  82                 return;
  83
  84         buf = cxt->virt_addr + (cxt->count * RECORD_SIZE);
  85         buf_orig = buf;
  86
  87         memset(buf, '\0', RECORD_SIZE);
  88         res = sprintf(buf, "%s", RAMOOPS_KERNMSG_HDR);
  89         buf += res;
  90         do_gettimeofday(&timestamp);
  91         res = sprintf(buf, "%lu.%lu\n", (long)timestamp.tv_sec, (long)timestamp.tv_usec);
  92         buf += res;
  93
  94         hdr_size = buf - buf_orig;
  95         l2_cpy = min(l2, RECORD_SIZE - hdr_size);
  96         l1_cpy = min(l1, RECORD_SIZE - hdr_size - l2_cpy);
  97
  98         s2_start = l2 - l2_cpy;
  99         s1_start = l1 - l1_cpy;
 100
 101         memcpy(buf, s1 + s1_start, l1_cpy);
 102         memcpy(buf + l1_cpy, s2 + s2_start, l2_cpy);
 103
 104         cxt->count = (cxt->count + 1) % cxt->max_count;
 105 }
 106
 107 static int __init ramoops_probe(struct platform_device *pdev)
 108 {
 109         struct ramoops_platform_data *pdata = pdev->dev.platform_data;
 110         struct ramoops_context *cxt = &oops_cxt;
 111         int err = -EINVAL;
 112
 113         if (!pdata->mem_size) {
 114                 printk(KERN_ERR "ramoops: invalid size specification");
 115                 goto fail3;
 116         }
 117
 118         rounddown_pow_of_two(pdata->mem_size);
 119
 120         if (pdata->mem_size < RECORD_SIZE) {
 121                 printk(KERN_ERR "ramoops: size too small");
 122                 goto fail3;
 123         }
 124
 125         cxt->max_count = pdata->mem_size / RECORD_SIZE;
 126         cxt->count = 0;
 127         cxt->size = pdata->mem_size;
 128         cxt->phys_addr = pdata->mem_address;
 129
 130         if (!request_mem_region(cxt->phys_addr, cxt->size, "ramoops")) {
 131                 printk(KERN_ERR "ramoops: request mem region failed");
 132                 err = -EINVAL;
 133                 goto fail3;
 134         }
 135
 136         cxt->virt_addr = ioremap(cxt->phys_addr,  cxt->size);
 137         if (!cxt->virt_addr) {
 138                 printk(KERN_ERR "ramoops: ioremap failed");
 139                 goto fail2;
 140         }
 141
 142         cxt->dump.dump = ramoops_do_dump;
 143         err = kmsg_dump_register(&cxt->dump);
 144         if (err) {
 145                 printk(KERN_ERR "ramoops: registering kmsg dumper failed");
 146                 goto fail1;
 147         }
 148
 149         return 0;
 150
 151 fail1:
 152         iounmap(cxt->virt_addr);
 153 fail2:
 154         release_mem_region(cxt->phys_addr, cxt->size);
 155 fail3:
 156         return err;
 157 }
 158
 159 static int __exit ramoops_remove(struct platform_device *pdev)
 160 {
 161         struct ramoops_context *cxt = &oops_cxt;
 162
 163         if (kmsg_dump_unregister(&cxt->dump) < 0)
 164                 printk(KERN_WARNING "ramoops: could not unregister kmsg_dumper");
 165
 166         iounmap(cxt->virt_addr);
 167         release_mem_region(cxt->phys_addr, cxt->size);
 168         return 0;
 169 }
 170
 171 static struct platform_driver ramoops_driver = {
 172         .remove         = __exit_p(ramoops_remove),
 173         .driver         = {
 174                 .name   = "ramoops",
 175                 .owner  = THIS_MODULE,
 176         },
 177 };
 178
 179 static int __init ramoops_init(void)
 180 {
 181         int ret;
 182         ret = platform_driver_probe(&ramoops_driver, ramoops_probe);
 183         if (ret == -ENODEV) {
 184                 /*
 185                  * If we didn't find a platform device, we use module parameters
 186                  * building platform data on the fly.
 187                  */
 188                 dummy_data = kzalloc(sizeof(struct ramoops_platform_data),
 189                                      GFP_KERNEL);
 190                 if (!dummy_data)
 191                         return -ENOMEM;
 192                 dummy_data->mem_size = mem_size;
 193                 dummy_data->mem_address = mem_address;
 194                 dummy = platform_create_bundle(&ramoops_driver, ramoops_probe,
 195                         NULL, 0, dummy_data,
 196                         sizeof(struct ramoops_platform_data));
 197
 198                 if (IS_ERR(dummy))
 199                         ret = PTR_ERR(dummy);
 200                 else
 201                         ret = 0;
 202         }
 203
 204         return ret;
 205 }
 206
 207 static void __exit ramoops_exit(void)
 208 {
 209         platform_driver_unregister(&ramoops_driver);
 210         kfree(dummy_data);
 211 }
 212
 213 module_init(ramoops_init);
 214 module_exit(ramoops_exit);
 215
 216 MODULE_LICENSE("GPL");
 217 MODULE_AUTHOR("Marco Stornelli <marco.stornelli@gmail.com>");
 218 MODULE_DESCRIPTION("RAM Oops/Panic logger/driver");