openwrt/target/linux/generic/pending-3.18/930-crashlog.patch

--- /dev/null
+++ b/include/linux/crashlog.h
@@ -0,0 +1,17 @@
+#ifndef __CRASHLOG_H
+#define __CRASHLOG_H
+
+#ifdef CONFIG_CRASHLOG
+void crashlog_init_bootmem(struct bootmem_data *bdata);
+void crashlog_init_memblock(phys_addr_t addr, phys_addr_t size);
+#else
+static inline void crashlog_init_bootmem(struct bootmem_data *bdata)
+{
+}
+
+static inline void crashlog_init_memblock(phys_addr_t addr, phys_addr_t size)
+{
+}
+#endif
+
+#endif
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1279,6 +1279,10 @@ config RELAY
 
 	  If unsure, say N.
 
+config CRASHLOG
+	bool "Crash logging"
+	depends on (!NO_BOOTMEM || HAVE_MEMBLOCK) && !(ARM || SPARC || PPC)
+
 config BLK_DEV_INITRD
 	bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
 	depends on BROKEN || !FRV
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -96,6 +96,7 @@ obj-$(CONFIG_CRASH_DUMP) += crash_dump.o
 obj-$(CONFIG_JUMP_LABEL) += jump_label.o
 obj-$(CONFIG_CONTEXT_TRACKING) += context_tracking.o
 obj-$(CONFIG_TORTURE_TEST) += torture.o
+obj-$(CONFIG_CRASHLOG) += crashlog.o
 
 $(obj)/configs.o: $(obj)/config_data.h
 
--- /dev/null
+++ b/kernel/crashlog.c
@@ -0,0 +1,181 @@
+/*
+ * Crash information logger
+ * Copyright (C) 2010 Felix Fietkau <nbd@nbd.name>
+ *
+ * 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/memblock.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;
+
+#ifndef CONFIG_NO_BOOTMEM
+void __init crashlog_init_bootmem(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;
+}
+#endif
+
+#ifdef CONFIG_HAVE_MEMBLOCK
+void __init_memblock crashlog_init_memblock(phys_addr_t addr, phys_addr_t size)
+{
+	if (crashlog_addr)
+		return;
+
+	addr += size - CRASHLOG_OFFSET;
+	if (memblock_reserve(addr, CRASHLOG_SIZE)) {
+		printk("Crashlog failed to allocate RAM at address 0x%lx\n", (unsigned long) addr);
+		return;
+	}
+
+	crashlog_addr = addr;
+}
+#endif
+
+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 += vscnprintf(
+		&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)
+{
+	struct timeval tv;
+	struct module *m;
+	char *buf;
+	size_t 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];
+
+	kmsg_dump_get_buffer(dumper, true, buf, get_maxlen(), &len);
+
+	crashlog_buf->len += len;
+}
+
+
+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.max_reason = KMSG_DUMP_OOPS;
+	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/export.h>
 #include <linux/kmemleak.h>
 #include <linux/range.h>
+#include <linux/crashlog.h>
 #include <linux/memblock.h>
 #include <linux/bug.h>
 #include <linux/io.h>
@@ -177,6 +178,7 @@ static unsigned long __init free_all_boo
 	if (!bdata->node_bootmem_map)
 		return 0;
 
+	crashlog_init_bootmem(bdata);
 	map = bdata->node_bootmem_map;
 	start = bdata->node_min_pfn;
 	end = bdata->node_low_pfn;
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -105,6 +105,9 @@ static LIST_HEAD(modules);
 #ifdef CONFIG_KGDB_KDB
 struct list_head *kdb_modules = &modules; /* kdb needs the list of modules */
 #endif /* CONFIG_KGDB_KDB */
+#ifdef CONFIG_CRASHLOG
+struct list_head *crashlog_modules = &modules;
+#endif
 
 #ifdef CONFIG_MODULE_SIG
 #ifdef CONFIG_MODULE_SIG_FORCE
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -19,6 +19,7 @@
 #include <linux/debugfs.h>
 #include <linux/seq_file.h>
 #include <linux/memblock.h>
+#include <linux/crashlog.h>
 
 #include <asm-generic/sections.h>
 #include <linux/io.h>
@@ -477,6 +478,8 @@ static void __init_memblock memblock_ins
 	memblock_set_region_node(rgn, nid);
 	type->cnt++;
 	type->total_size += size;
+	if (type == &memblock.memory && idx == 0)
+		crashlog_init_memblock(base, size);
 }
 
 /**