4 Allow user space to create what appear to be multiple instances
11 bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
12 depends on BROKEN || !FRV
16 obj-$(CONFIG_TRACING) += trace/
17 obj-$(CONFIG_SMP) += sched_cpupri.o
18 obj-$(CONFIG_SLOW_WORK) += slow-work.o
19 +obj-$(CONFIG_CRASHLOG) += crashlog.o
21 ifneq ($(CONFIG_SCHED_OMIT_FRAME_POINTER),y)
22 # According to Alan Modra <alan@linuxcare.com.au>, the -fno-omit-frame-pointer is
26 #include <linux/pfn.h>
27 #include <linux/bootmem.h>
28 #include <linux/module.h>
29 +#include <linux/crashlog.h>
34 if (!bdata->node_bootmem_map)
37 + crashlog_init_mem(bdata);
38 start = bdata->node_min_pfn;
39 end = bdata->node_low_pfn;
44 DEFINE_MUTEX(module_mutex);
45 EXPORT_SYMBOL_GPL(module_mutex);
46 static LIST_HEAD(modules);
47 +#ifdef CONFIG_CRASHLOG
48 +struct list_head *crashlog_modules = &modules;
51 /* Waiting for a module to finish initializing? */
52 static DECLARE_WAIT_QUEUE_HEAD(module_wq);
54 +++ b/include/linux/crashlog.h
59 +#ifdef CONFIG_CRASHLOG
60 +void __init crashlog_init_mem(struct bootmem_data *bdata);
62 +static inline void crashlog_init_mem(struct bootmem_data *bdata)
69 +++ b/kernel/crashlog.c
72 + * Crash information logger
73 + * Copyright (C) 2010 Felix Fietkau <nbd@openwrt.org>
75 + * Based on ramoops.c
76 + * Copyright (C) 2010 Marco Stornelli <marco.stornelli@gmail.com>
78 + * This program is free software; you can redistribute it and/or
79 + * modify it under the terms of the GNU General Public License
80 + * version 2 as published by the Free Software Foundation.
82 + * This program is distributed in the hope that it will be useful, but
83 + * WITHOUT ANY WARRANTY; without even the implied warranty of
84 + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
85 + * General Public License for more details.
87 + * You should have received a copy of the GNU General Public License
88 + * along with this program; if not, write to the Free Software
89 + * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
94 +#include <linux/module.h>
95 +#include <linux/bootmem.h>
96 +#include <linux/debugfs.h>
97 +#include <linux/crashlog.h>
98 +#include <linux/kmsg_dump.h>
99 +#include <linux/module.h>
100 +#include <linux/pfn.h>
103 +#define CRASHLOG_PAGES 4
104 +#define CRASHLOG_SIZE (CRASHLOG_PAGES * PAGE_SIZE)
105 +#define CRASHLOG_MAGIC 0xa1eedead
108 + * Start the log at 1M before the end of RAM, as some boot loaders like
109 + * to use the end of the RAM for stack usage and other things
110 + * If this fails, fall back to using the last part.
112 +#define CRASHLOG_OFFSET (1024 * 1024)
114 +struct crashlog_data {
120 +static struct debugfs_blob_wrapper crashlog_blob;
121 +static unsigned long crashlog_addr = 0;
122 +static struct crashlog_data *crashlog_buf;
123 +static struct kmsg_dumper dump;
124 +static bool first = true;
126 +extern struct list_head *crashlog_modules;
128 +void __init crashlog_init_mem(bootmem_data_t *bdata)
130 + unsigned long addr;
135 + addr = PFN_PHYS(bdata->node_low_pfn) - CRASHLOG_OFFSET;
136 + if (reserve_bootmem(addr, CRASHLOG_SIZE, BOOTMEM_EXCLUSIVE) < 0) {
137 + printk("Crashlog failed to allocate RAM at address 0x%lx\n", addr);
138 + bdata->node_low_pfn -= CRASHLOG_PAGES;
139 + addr = PFN_PHYS(bdata->node_low_pfn);
141 + crashlog_addr = addr;
144 +static void __init crashlog_copy(void)
146 + if (crashlog_buf->magic != CRASHLOG_MAGIC)
149 + if (!crashlog_buf->len || crashlog_buf->len >
150 + CRASHLOG_SIZE - sizeof(*crashlog_buf))
153 + crashlog_blob.size = crashlog_buf->len;
154 + crashlog_blob.data = kmemdup(crashlog_buf->data,
155 + crashlog_buf->len, GFP_KERNEL);
157 + debugfs_create_blob("crashlog", 0700, NULL, &crashlog_blob);
160 +static int get_maxlen(void)
162 + return CRASHLOG_SIZE - sizeof(*crashlog_buf) - crashlog_buf->len;
165 +static void crashlog_printf(const char *fmt, ...)
168 + int len = get_maxlen();
173 + va_start(args, fmt);
174 + crashlog_buf->len += vsnprintf(
175 + &crashlog_buf->data[crashlog_buf->len],
180 +static void crashlog_do_dump(struct kmsg_dumper *dumper,
181 + enum kmsg_dump_reason reason, const char *s1, unsigned long l1,
182 + const char *s2, unsigned long l2)
184 + unsigned long s1_start, s2_start;
185 + unsigned long l1_cpy, l2_cpy;
192 + crashlog_printf("\n===================================\n");
194 + do_gettimeofday(&tv);
195 + crashlog_printf("Time: %lu.%lu\n",
196 + (long)tv.tv_sec, (long)tv.tv_usec);
199 + crashlog_printf("Modules:");
200 + list_for_each_entry(m, crashlog_modules, list) {
201 + crashlog_printf("\t%s@%p+%x", m->name,
202 + m->module_core, m->core_size,
203 + m->module_init, m->init_size);
205 + crashlog_printf("\n");
209 + buf = (char *)&crashlog_buf->data[crashlog_buf->len];
210 + len = get_maxlen();
212 + l2_cpy = min(l2, (unsigned long)len);
213 + l1_cpy = min(l1, (unsigned long)len - l2_cpy);
215 + s2_start = l2 - l2_cpy;
216 + s1_start = l1 - l1_cpy;
218 + memcpy(buf, s1 + s1_start, l1_cpy);
219 + memcpy(buf + l1_cpy, s2 + s2_start, l2_cpy);
220 + crashlog_buf->len += l1_cpy + l2_cpy;
224 +int __init crashlog_init_fs(void)
226 + if (!crashlog_addr)
229 + crashlog_buf = ioremap(crashlog_addr, CRASHLOG_SIZE);
233 + crashlog_buf->magic = CRASHLOG_MAGIC;
234 + crashlog_buf->len = 0;
236 + dump.dump = crashlog_do_dump;
237 + kmsg_dump_register(&dump);
241 +module_init(crashlog_init_fs);