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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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
23
24 #include <linux/kernel.h>
25 #include <linux/module.h>
26 #include <linux/kmsg_dump.h>
27 #include <linux/time.h>
28 #include <linux/io.h>
29 #include <linux/ioport.h>
30 #include <linux/platform_device.h>
31 #include <linux/slab.h>
32 #include <linux/ramoops.h>
33
34 #define RAMOOPS_KERNMSG_HDR "===="
35 #define MIN_MEM_SIZE 4096UL
36
37 static ulong record_size = MIN_MEM_SIZE;
38 module_param(record_size, ulong, 0400);
39 MODULE_PARM_DESC(record_size,
40                 "size of each dump done on oops/panic");
41
42 static ulong mem_address;
43 module_param(mem_address, ulong, 0400);
44 MODULE_PARM_DESC(mem_address,
45                 "start of reserved RAM used to store oops/panic logs");
46
47 static ulong mem_size;
48 module_param(mem_size, ulong, 0400);
49 MODULE_PARM_DESC(mem_size,
50                 "size of reserved RAM used to store oops/panic logs");
51
52 static int dump_oops = 1;
53 module_param(dump_oops, int, 0600);
54 MODULE_PARM_DESC(dump_oops,
55                 "set to 1 to dump oopses, 0 to only dump panics (default 1)");
56
57 static struct ramoops_context {
58         struct kmsg_dumper dump;
59         void *virt_addr;
60         phys_addr_t phys_addr;
61         unsigned long size;
62         unsigned long record_size;
63         int dump_oops;
64         int count;
65         int max_count;
66 } oops_cxt;
67
68 static struct platform_device *dummy;
69 static struct ramoops_platform_data *dummy_data;
70
71 static void ramoops_do_dump(struct kmsg_dumper *dumper,
72                 enum kmsg_dump_reason reason, const char *s1, unsigned long l1,
73                 const char *s2, unsigned long l2)
74 {
75         struct ramoops_context *cxt = container_of(dumper,
76                         struct ramoops_context, dump);
77         unsigned long s1_start, s2_start;
78         unsigned long l1_cpy, l2_cpy;
79         int res, hdr_size;
80         char *buf, *buf_orig;
81         struct timeval timestamp;
82
83         if (reason != KMSG_DUMP_OOPS &&
84             reason != KMSG_DUMP_PANIC &&
85             reason != KMSG_DUMP_KEXEC)
86                 return;
87
88         /* Only dump oopses if dump_oops is set */
89         if (reason == KMSG_DUMP_OOPS && !cxt->dump_oops)
90                 return;
91
92         buf = cxt->virt_addr + (cxt->count * cxt->record_size);
93         buf_orig = buf;
94
95         memset(buf, '\0', cxt->record_size);
96         res = sprintf(buf, "%s", RAMOOPS_KERNMSG_HDR);
97         buf += res;
98         do_gettimeofday(&timestamp);
99         res = sprintf(buf, "%lu.%lu\n", (long)timestamp.tv_sec, (long)timestamp.tv_usec);
100         buf += res;
101
102         hdr_size = buf - buf_orig;
103         l2_cpy = min(l2, cxt->record_size - hdr_size);
104         l1_cpy = min(l1, cxt->record_size - hdr_size - l2_cpy);
105
106         s2_start = l2 - l2_cpy;
107         s1_start = l1 - l1_cpy;
108
109         memcpy(buf, s1 + s1_start, l1_cpy);
110         memcpy(buf + l1_cpy, s2 + s2_start, l2_cpy);
111
112         cxt->count = (cxt->count + 1) % cxt->max_count;
113 }
114
115 static int __init ramoops_probe(struct platform_device *pdev)
116 {
117         struct ramoops_platform_data *pdata = pdev->dev.platform_data;
118         struct ramoops_context *cxt = &oops_cxt;
119         int err = -EINVAL;
120
121         if (!pdata->mem_size || !pdata->record_size) {
122                 pr_err("The memory size and the record size must be "
123                         "non-zero\n");
124                 goto fail3;
125         }
126
127         rounddown_pow_of_two(pdata->mem_size);
128         rounddown_pow_of_two(pdata->record_size);
129
130         /* Check for the minimum memory size */
131         if (pdata->mem_size < MIN_MEM_SIZE &&
132                         pdata->record_size < MIN_MEM_SIZE) {
133                 pr_err("memory size too small, minium is %lu\n", MIN_MEM_SIZE);
134                 goto fail3;
135         }
136
137         if (pdata->mem_size < pdata->record_size) {
138                 pr_err("The memory size must be larger than the "
139                         "records size\n");
140                 goto fail3;
141         }
142
143         cxt->max_count = pdata->mem_size / pdata->record_size;
144         cxt->count = 0;
145         cxt->size = pdata->mem_size;
146         cxt->phys_addr = pdata->mem_address;
147         cxt->record_size = pdata->record_size;
148         cxt->dump_oops = pdata->dump_oops;
149
150         if (!request_mem_region(cxt->phys_addr, cxt->size, "ramoops")) {
151                 pr_err("request mem region failed\n");
152                 err = -EINVAL;
153                 goto fail3;
154         }
155
156         cxt->virt_addr = ioremap(cxt->phys_addr,  cxt->size);
157         if (!cxt->virt_addr) {
158                 pr_err("ioremap failed\n");
159                 goto fail2;
160         }
161
162         cxt->dump.dump = ramoops_do_dump;
163         err = kmsg_dump_register(&cxt->dump);
164         if (err) {
165                 pr_err("registering kmsg dumper failed\n");
166                 goto fail1;
167         }
168
169         return 0;
170
171 fail1:
172         iounmap(cxt->virt_addr);
173 fail2:
174         release_mem_region(cxt->phys_addr, cxt->size);
175 fail3:
176         return err;
177 }
178
179 static int __exit ramoops_remove(struct platform_device *pdev)
180 {
181         struct ramoops_context *cxt = &oops_cxt;
182
183         if (kmsg_dump_unregister(&cxt->dump) < 0)
184                 pr_warn("could not unregister kmsg_dumper\n");
185
186         iounmap(cxt->virt_addr);
187         release_mem_region(cxt->phys_addr, cxt->size);
188         return 0;
189 }
190
191 static struct platform_driver ramoops_driver = {
192         .remove         = __exit_p(ramoops_remove),
193         .driver         = {
194                 .name   = "ramoops",
195                 .owner  = THIS_MODULE,
196         },
197 };
198
199 static int __init ramoops_init(void)
200 {
201         int ret;
202         ret = platform_driver_probe(&ramoops_driver, ramoops_probe);
203         if (ret == -ENODEV) {
204                 /*
205                  * If we didn't find a platform device, we use module parameters
206                  * building platform data on the fly.
207                  */
208                 pr_info("platform device not found, using module parameters\n");
209                 dummy_data = kzalloc(sizeof(struct ramoops_platform_data),
210                                      GFP_KERNEL);
211                 if (!dummy_data)
212                         return -ENOMEM;
213                 dummy_data->mem_size = mem_size;
214                 dummy_data->mem_address = mem_address;
215                 dummy_data->record_size = record_size;
216                 dummy_data->dump_oops = dump_oops;
217                 dummy = platform_create_bundle(&ramoops_driver, ramoops_probe,
218                         NULL, 0, dummy_data,
219                         sizeof(struct ramoops_platform_data));
220
221                 if (IS_ERR(dummy))
222                         ret = PTR_ERR(dummy);
223                 else
224                         ret = 0;
225         }
226
227         return ret;
228 }
229
230 static void __exit ramoops_exit(void)
231 {
232         platform_driver_unregister(&ramoops_driver);
233         kfree(dummy_data);
234 }
235
236 module_init(ramoops_init);
237 module_exit(ramoops_exit);
238
239 MODULE_LICENSE("GPL");
240 MODULE_AUTHOR("Marco Stornelli <marco.stornelli@gmail.com>");
241 MODULE_DESCRIPTION("RAM Oops/Panic logger/driver");