/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
 35static ulong mem_address;
 36module_param(mem_address, ulong, 0400);
 37MODULE_PARM_DESC(mem_address,
 38		"start of reserved RAM used to store oops/panic logs");
 39
 40static ulong mem_size;
 41module_param(mem_size, ulong, 0400);
 42MODULE_PARM_DESC(mem_size,
 43		"size of reserved RAM used to store oops/panic logs");
 44
 45static int dump_oops = 1;
 46module_param(dump_oops, int, 0600);
 47MODULE_PARM_DESC(dump_oops,
 48		"set to 1 to dump oopses, 0 to only dump panics (default 1)");
 49
 50static 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
 59static 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
103static 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
152fail1:
153	iounmap(cxt->virt_addr);
154fail2:
155	release_mem_region(cxt->phys_addr, cxt->size);
156fail3:
157	return err;
158}
159
160static 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
172static struct platform_driver ramoops_driver = {
173	.remove		= __exit_p(ramoops_remove),
174	.driver		= {
175		.name	= "ramoops",
176		.owner	= THIS_MODULE,
177	},
178};
179
180static int __init ramoops_init(void)
181{
182	return platform_driver_probe(&ramoops_driver, ramoops_probe);
183}
184
185static void __exit ramoops_exit(void)
186{
187	platform_driver_unregister(&ramoops_driver);
188}
189
190module_init(ramoops_init);
191module_exit(ramoops_exit);
192
193MODULE_LICENSE("GPL");
194MODULE_AUTHOR("Marco Stornelli <marco.stornelli@gmail.com>");
195MODULE_DESCRIPTION("RAM Oops/Panic logger/driver");