2 * RAM Oops/Panic logger
4 * Copyright (C) 2010 Marco Stornelli <marco.stornelli@gmail.com>
5 * Copyright (C) 2011 Kees Cook <keescook@chromium.org>
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * version 2 as published by the Free Software Foundation.
11 * This program is distributed in the hope that it will be useful, but
12 * WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
23 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
25 #include <linux/kernel.h>
26 #include <linux/err.h>
27 #include <linux/module.h>
28 #include <linux/pstore.h>
29 #include <linux/time.h>
31 #include <linux/ioport.h>
32 #include <linux/platform_device.h>
33 #include <linux/slab.h>
34 #include <linux/pstore_ram.h>
36 #define RAMOOPS_KERNMSG_HDR "===="
37 #define MIN_MEM_SIZE 4096UL
39 static ulong record_size = MIN_MEM_SIZE;
40 module_param(record_size, ulong, 0400);
41 MODULE_PARM_DESC(record_size,
42 "size of each dump done on oops/panic");
44 static ulong mem_address;
45 module_param(mem_address, ulong, 0400);
46 MODULE_PARM_DESC(mem_address,
47 "start of reserved RAM used to store oops/panic logs");
49 static ulong mem_size;
50 module_param(mem_size, ulong, 0400);
51 MODULE_PARM_DESC(mem_size,
52 "size of reserved RAM used to store oops/panic logs");
54 static int dump_oops = 1;
55 module_param(dump_oops, int, 0600);
56 MODULE_PARM_DESC(dump_oops,
57 "set to 1 to dump oopses, 0 to only dump panics (default 1)");
59 struct ramoops_context {
61 phys_addr_t phys_addr;
66 unsigned int max_count;
67 unsigned int read_count;
68 struct pstore_info pstore;
71 static struct platform_device *dummy;
72 static struct ramoops_platform_data *dummy_data;
74 static int ramoops_pstore_open(struct pstore_info *psi)
76 struct ramoops_context *cxt = psi->data;
82 static ssize_t ramoops_pstore_read(u64 *id, enum pstore_type_id *type,
83 struct timespec *time,
85 struct pstore_info *psi)
89 struct ramoops_context *cxt = psi->data;
91 if (cxt->read_count >= cxt->max_count)
93 *id = cxt->read_count++;
94 /* Only supports dmesg output so far. */
95 *type = PSTORE_TYPE_DMESG;
96 /* TODO(kees): Bogus time for the moment. */
100 rambuf = cxt->virt_addr + (*id * cxt->record_size);
101 size = strnlen(rambuf, cxt->record_size);
102 *buf = kmalloc(size, GFP_KERNEL);
105 memcpy(*buf, rambuf, size);
110 static int ramoops_pstore_write(enum pstore_type_id type,
111 enum kmsg_dump_reason reason,
114 size_t size, struct pstore_info *psi)
118 struct timeval timestamp;
119 struct ramoops_context *cxt = psi->data;
120 size_t available = cxt->record_size;
122 /* Currently ramoops is designed to only store dmesg dumps. */
123 if (type != PSTORE_TYPE_DMESG)
126 /* Out of the various dmesg dump types, ramoops is currently designed
127 * to only store crash logs, rather than storing general kernel logs.
129 if (reason != KMSG_DUMP_OOPS &&
130 reason != KMSG_DUMP_PANIC)
133 /* Skip Oopes when configured to do so. */
134 if (reason == KMSG_DUMP_OOPS && !cxt->dump_oops)
137 /* Explicitly only take the first part of any new crash.
138 * If our buffer is larger than kmsg_bytes, this can never happen,
139 * and if our buffer is smaller than kmsg_bytes, we don't want the
140 * report split across multiple records.
145 buf = cxt->virt_addr + (cxt->count * cxt->record_size);
147 res = sprintf(buf, "%s", RAMOOPS_KERNMSG_HDR);
151 do_gettimeofday(×tamp);
152 res = sprintf(buf, "%lu.%lu\n", (long)timestamp.tv_sec, (long)timestamp.tv_usec);
156 if (size > available)
159 memcpy(buf, cxt->pstore.buf, size);
160 memset(buf + size, '\0', available - size);
162 cxt->count = (cxt->count + 1) % cxt->max_count;
167 static int ramoops_pstore_erase(enum pstore_type_id type, u64 id,
168 struct pstore_info *psi)
171 struct ramoops_context *cxt = psi->data;
173 if (id >= cxt->max_count)
176 buf = cxt->virt_addr + (id * cxt->record_size);
177 memset(buf, '\0', cxt->record_size);
182 static struct ramoops_context oops_cxt = {
184 .owner = THIS_MODULE,
186 .open = ramoops_pstore_open,
187 .read = ramoops_pstore_read,
188 .write = ramoops_pstore_write,
189 .erase = ramoops_pstore_erase,
193 static int __init ramoops_probe(struct platform_device *pdev)
195 struct ramoops_platform_data *pdata = pdev->dev.platform_data;
196 struct ramoops_context *cxt = &oops_cxt;
199 /* Only a single ramoops area allowed at a time, so fail extra
205 if (!pdata->mem_size || !pdata->record_size) {
206 pr_err("The memory size and the record size must be "
211 pdata->mem_size = rounddown_pow_of_two(pdata->mem_size);
212 pdata->record_size = rounddown_pow_of_two(pdata->record_size);
214 /* Check for the minimum memory size */
215 if (pdata->mem_size < MIN_MEM_SIZE &&
216 pdata->record_size < MIN_MEM_SIZE) {
217 pr_err("memory size too small, minimum is %lu\n",
222 if (pdata->mem_size < pdata->record_size) {
223 pr_err("The memory size must be larger than the "
228 cxt->max_count = pdata->mem_size / pdata->record_size;
230 cxt->size = pdata->mem_size;
231 cxt->phys_addr = pdata->mem_address;
232 cxt->record_size = pdata->record_size;
233 cxt->dump_oops = pdata->dump_oops;
235 cxt->pstore.data = cxt;
236 cxt->pstore.bufsize = cxt->record_size;
237 cxt->pstore.buf = kmalloc(cxt->pstore.bufsize, GFP_KERNEL);
238 spin_lock_init(&cxt->pstore.buf_lock);
239 if (!cxt->pstore.buf) {
240 pr_err("cannot allocate pstore buffer\n");
244 if (!request_mem_region(cxt->phys_addr, cxt->size, "ramoops")) {
245 pr_err("request mem region (0x%lx@0x%llx) failed\n",
246 cxt->size, (unsigned long long)cxt->phys_addr);
251 cxt->virt_addr = ioremap(cxt->phys_addr, cxt->size);
252 if (!cxt->virt_addr) {
253 pr_err("ioremap failed\n");
254 goto fail_mem_region;
257 err = pstore_register(&cxt->pstore);
259 pr_err("registering with pstore failed\n");
264 * Update the module parameter variables as well so they are visible
265 * through /sys/module/ramoops/parameters/
267 mem_size = pdata->mem_size;
268 mem_address = pdata->mem_address;
269 record_size = pdata->record_size;
270 dump_oops = pdata->dump_oops;
272 pr_info("attached 0x%lx@0x%llx (%ux0x%zx)\n",
273 cxt->size, (unsigned long long)cxt->phys_addr,
274 cxt->max_count, cxt->record_size);
279 iounmap(cxt->virt_addr);
281 release_mem_region(cxt->phys_addr, cxt->size);
283 kfree(cxt->pstore.buf);
285 cxt->pstore.bufsize = 0;
291 static int __exit ramoops_remove(struct platform_device *pdev)
294 /* TODO(kees): We cannot unload ramoops since pstore doesn't support
297 struct ramoops_context *cxt = &oops_cxt;
299 iounmap(cxt->virt_addr);
300 release_mem_region(cxt->phys_addr, cxt->size);
303 /* TODO(kees): When pstore supports unregistering, call it here. */
304 kfree(cxt->pstore.buf);
305 cxt->pstore.bufsize = 0;
312 static struct platform_driver ramoops_driver = {
313 .remove = __exit_p(ramoops_remove),
316 .owner = THIS_MODULE,
320 static int __init ramoops_init(void)
323 ret = platform_driver_probe(&ramoops_driver, ramoops_probe);
324 if (ret == -ENODEV) {
326 * If we didn't find a platform device, we use module parameters
327 * building platform data on the fly.
329 pr_info("platform device not found, using module parameters\n");
330 dummy_data = kzalloc(sizeof(struct ramoops_platform_data),
334 dummy_data->mem_size = mem_size;
335 dummy_data->mem_address = mem_address;
336 dummy_data->record_size = record_size;
337 dummy_data->dump_oops = dump_oops;
338 dummy = platform_create_bundle(&ramoops_driver, ramoops_probe,
340 sizeof(struct ramoops_platform_data));
343 ret = PTR_ERR(dummy);
351 static void __exit ramoops_exit(void)
353 platform_driver_unregister(&ramoops_driver);
357 module_init(ramoops_init);
358 module_exit(ramoops_exit);
360 MODULE_LICENSE("GPL");
361 MODULE_AUTHOR("Marco Stornelli <marco.stornelli@gmail.com>");
362 MODULE_DESCRIPTION("RAM Oops/Panic logger/driver");