kernel: add the new 'crashlog' feature, which tries to store kernel oops/panic logs in a fixed location in RAM to recover them after the reboot and make them available to user space using debugfs

SVN-Revision: 22305

1 files changed, 241 insertions, 0 deletions

diff --git a/target/linux/generic/patches-2.6.34/930-crashlog.patch b/target/linux/generic/patches-2.6.34/930-crashlog.patch
new file mode 100644
index 0000000..ab6f542
--- /dev/null
+++ b/target/linux/generic/patches-2.6.34/930-crashlog.patch
@@ -0,0 +1,241 @@
+--- /dev/null
++++ b/include/linux/crashlog.h
+@@ -0,0 +1,12 @@
++#ifndef __CRASHLOG_H
++#define __CRASHLOG_H
++
++#ifdef CONFIG_CRASHLOG
++void __init crashlog_init_mem(struct bootmem_data *bdata);
++#else
++static inline void crashlog_init_mem(struct bootmem_data *bdata)
++{
++}
++#endif
++
++#endif
+--- a/init/Kconfig
++++ b/init/Kconfig
+@@ -715,6 +715,9 @@ config NET_NS
+ 	  Allow user space to create what appear to be multiple instances
+ 	  of the network stack.
+ 
++config CRASHLOG
++	bool "Crash logging"
++
+ config BLK_DEV_INITRD
+ 	bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
+ 	depends on BROKEN || !FRV
+--- a/kernel/Makefile
++++ b/kernel/Makefile
+@@ -105,6 +105,7 @@ obj-$(CONFIG_PERF_EVENTS) += perf_event.
+ obj-$(CONFIG_HAVE_HW_BREAKPOINT) += hw_breakpoint.o
+ obj-$(CONFIG_USER_RETURN_NOTIFIER) += user-return-notifier.o
+ obj-$(CONFIG_PADATA) += padata.o
++obj-$(CONFIG_CRASHLOG) += crashlog.o
+ 
+ ifneq ($(CONFIG_SCHED_OMIT_FRAME_POINTER),y)
+ # According to Alan Modra <alan@linuxcare.com.au>, the -fno-omit-frame-pointer is
+--- /dev/null
++++ b/kernel/crashlog.c
+@@ -0,0 +1,171 @@
++/*
++ * Crash information logger
++ * Copyright (C) 2010 Felix Fietkau <nbd@openwrt.org>
++ *
++ * Based on ramoops.c
++ *   Copyright (C) 2010 Marco Stornelli <marco.stornelli@gmail.com>
++ *
++ * This program is free software; you can redistribute it and/or
++ * modify it under the terms of the GNU General Public License
++ * version 2 as published by the Free Software Foundation.
++ *
++ * This program is distributed in the hope that it will be useful, but
++ * WITHOUT ANY WARRANTY; without even the implied warranty of
++ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
++ * General Public License for more details.
++ *
++ * You should have received a copy of the GNU General Public License
++ * along with this program; if not, write to the Free Software
++ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
++ * 02110-1301 USA
++ *
++ */
++
++#include <linux/module.h>
++#include <linux/bootmem.h>
++#include <linux/debugfs.h>
++#include <linux/crashlog.h>
++#include <linux/kmsg_dump.h>
++#include <linux/module.h>
++#include <linux/pfn.h>
++#include <asm/io.h>
++
++#define CRASHLOG_PAGES	4
++#define CRASHLOG_SIZE	(CRASHLOG_PAGES * PAGE_SIZE)
++#define CRASHLOG_MAGIC	0xa1eedead
++
++/*
++ * Start the log at 1M before the end of RAM, as some boot loaders like
++ * to use the end of the RAM for stack usage and other things
++ * If this fails, fall back to using the last part.
++ */
++#define CRASHLOG_OFFSET	(1024 * 1024)
++
++struct crashlog_data {
++	u32 magic;
++	u32 len;
++	u8 data[];
++};
++
++static struct debugfs_blob_wrapper crashlog_blob;
++static unsigned long crashlog_addr = 0;
++static struct crashlog_data *crashlog_buf;
++static struct kmsg_dumper dump;
++static bool first = true;
++
++extern struct list_head *crashlog_modules;
++
++void __init crashlog_init_mem(bootmem_data_t *bdata)
++{
++	unsigned long addr;
++
++	if (crashlog_addr)
++		return;
++
++	addr = PFN_PHYS(bdata->node_low_pfn) - CRASHLOG_OFFSET;
++	if (reserve_bootmem(addr, CRASHLOG_SIZE, BOOTMEM_EXCLUSIVE) < 0) {
++		printk("Crashlog failed to allocate RAM at address 0x%lx\n", addr);
++		bdata->node_low_pfn -= CRASHLOG_PAGES;
++		addr = PFN_PHYS(bdata->node_low_pfn);
++	}
++	crashlog_addr = addr;
++}
++
++static void __init crashlog_copy(void)
++{
++	if (crashlog_buf->magic != CRASHLOG_MAGIC)
++		return;
++
++	if (!crashlog_buf->len || crashlog_buf->len >
++	    CRASHLOG_SIZE - sizeof(*crashlog_buf))
++		return;
++
++	crashlog_blob.size = crashlog_buf->len;
++	crashlog_blob.data = kmemdup(crashlog_buf->data,
++		crashlog_buf->len, GFP_KERNEL);
++
++	debugfs_create_blob("crashlog", 0700, NULL, &crashlog_blob);
++}
++
++static int get_maxlen(void)
++{
++	return CRASHLOG_SIZE - sizeof(*crashlog_buf) - crashlog_buf->len;
++}
++
++static void crashlog_printf(const char *fmt, ...)
++{
++	va_list args;
++	int len = get_maxlen();
++
++	if (!len)
++		return;
++
++	va_start(args, fmt);
++	crashlog_buf->len += vsnprintf(
++		&crashlog_buf->data[crashlog_buf->len],
++		len, fmt, args);
++	va_end(args);
++}
++
++static void crashlog_do_dump(struct kmsg_dumper *dumper,
++		enum kmsg_dump_reason reason, const char *s1, unsigned long l1,
++		const char *s2, unsigned long l2)
++{
++	unsigned long s1_start, s2_start;
++	unsigned long l1_cpy, l2_cpy;
++	struct timeval tv;
++	struct module *m;
++	char *buf;
++	int len;
++
++	if (!first)
++		crashlog_printf("\n===================================\n");
++
++	do_gettimeofday(&tv);
++	crashlog_printf("Time: %lu.%lu\n",
++		(long)tv.tv_sec, (long)tv.tv_usec);
++
++	if (first) {
++		crashlog_printf("Modules:");
++		list_for_each_entry(m, crashlog_modules, list) {
++			crashlog_printf("\t%s@%p+%x", m->name,
++			m->module_core, m->core_size,
++			m->module_init, m->init_size);
++		}
++		crashlog_printf("\n");
++		first = false;
++	}
++
++	buf = (char *)&crashlog_buf->data[crashlog_buf->len];
++	len = get_maxlen();
++
++	l2_cpy = min(l2, (unsigned long)len);
++	l1_cpy = min(l1, (unsigned long)len - l2_cpy);
++
++	s2_start = l2 - l2_cpy;
++	s1_start = l1 - l1_cpy;
++
++	memcpy(buf, s1 + s1_start, l1_cpy);
++	memcpy(buf + l1_cpy, s2 + s2_start, l2_cpy);
++	crashlog_buf->len += l1_cpy + l2_cpy;
++}
++
++
++int __init crashlog_init_fs(void)
++{
++	if (!crashlog_addr)
++		return -ENOMEM;
++
++	crashlog_buf = ioremap(crashlog_addr, CRASHLOG_SIZE);
++
++	crashlog_copy();
++
++	crashlog_buf->magic = CRASHLOG_MAGIC;
++	crashlog_buf->len = 0;
++
++	dump.dump = crashlog_do_dump;
++	kmsg_dump_register(&dump);
++
++	return 0;
++}
++module_init(crashlog_init_fs);
+--- a/mm/bootmem.c
++++ b/mm/bootmem.c
+@@ -15,6 +15,7 @@
+ #include <linux/module.h>
+ #include <linux/kmemleak.h>
+ #include <linux/range.h>
++#include <linux/crashlog.h>
+ 
+ #include <asm/bug.h>
+ #include <asm/io.h>
+@@ -226,6 +227,7 @@ static unsigned long __init free_all_boo
+ 	if (!bdata->node_bootmem_map)
+ 		return 0;
+ 
++	crashlog_init_mem(bdata);
+ 	start = bdata->node_min_pfn;
+ 	end = bdata->node_low_pfn;
+ 
+--- a/kernel/module.c
++++ b/kernel/module.c
+@@ -79,6 +79,9 @@ EXPORT_TRACEPOINT_SYMBOL(module_get);
+ DEFINE_MUTEX(module_mutex);
+ EXPORT_SYMBOL_GPL(module_mutex);
+ static LIST_HEAD(modules);
++#ifdef CONFIG_CRASHLOG
++struct list_head *crashlog_modules = &modules;
++#endif
+ 
+ /* Block module loading/unloading? */
+ int modules_disabled = 0;