2 files changed, 28 insertions, 16 deletions

diff --git a/drivers/of/Kconfig b/drivers/of/Kconfig
index be16ce2ffd69..fbe8f8d418f7 100644
--- a/drivers/of/Kconfig
+++ b/drivers/of/Kconfig
@@ -23,6 +23,7 @@ config OF_FLATTREE
         bool
         select DTC
         select LIBFDT
+        select CRC32
 
 config OF_EARLY_FLATTREE
         bool
diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index 83a8e1154602..cb19adfb3933 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -9,6 +9,7 @@
  * version 2 as published by the Free Software Foundation.
  */
 
+#include <linux/crc32.h>
 #include <linux/kernel.h>
 #include <linux/initrd.h>
 #include <linux/memblock.h>
@@ -22,6 +23,7 @@
 #include <linux/libfdt.h>
 #include <linux/debugfs.h>
 #include <linux/serial_core.h>
+#include <linux/sysfs.h>
 
 #include <asm/setup.h>  /* for COMMAND_LINE_SIZE */
 #include <asm/page.h>
@@ -423,6 +425,8 @@ void *initial_boot_params;
 
 #ifdef CONFIG_OF_EARLY_FLATTREE
 
+static u32 of_fdt_crc32;
+
 /**
  * res_mem_reserve_reg() - reserve all memory described in 'reg' property
  */
@@ -1003,6 +1007,8 @@ bool __init early_init_dt_verify(void *params)
 
         /* Setup flat device-tree pointer */
         initial_boot_params = params;
+        of_fdt_crc32 = crc32_be(~0, initial_boot_params,
+                                fdt_totalsize(initial_boot_params));
         return true;
 }
 
@@ -1080,27 +1086,32 @@ void __init unflatten_and_copy_device_tree(void)
         unflatten_device_tree();
 }
 
-#if defined(CONFIG_DEBUG_FS) && defined(DEBUG)
-static struct debugfs_blob_wrapper flat_dt_blob;
-
-static int __init of_flat_dt_debugfs_export_fdt(void)
+#ifdef CONFIG_SYSFS
+static ssize_t of_fdt_raw_read(struct file *filp, struct kobject *kobj,
+                               struct bin_attribute *bin_attr,
+                               char *buf, loff_t off, size_t count)
 {
-        struct dentry *d = debugfs_create_dir("device-tree", NULL);
-
-        if (!d)
-                return -ENOENT;
+        memcpy(buf, initial_boot_params + off, count);
+        return count;
+}
 
-        flat_dt_blob.data = initial_boot_params;
-        flat_dt_blob.size = fdt_totalsize(initial_boot_params);
+static int __init of_fdt_raw_init(void)
+{
+        static struct bin_attribute of_fdt_raw_attr =
+                __BIN_ATTR(fdt, S_IRUSR, of_fdt_raw_read, NULL, 0);
 
-        d = debugfs_create_blob("flat-device-tree", S_IFREG | S_IRUSR,
-                                d, &flat_dt_blob);
-        if (!d)
-                return -ENOENT;
+        if (!initial_boot_params)
+                return 0;
 
-        return 0;
+        if (of_fdt_crc32 != crc32_be(~0, initial_boot_params,
+                                     fdt_totalsize(initial_boot_params))) {
+                pr_warn("fdt: not creating '/sys/firmware/fdt': CRC check failed\n");
+                return 0;
+        }
+        of_fdt_raw_attr.size = fdt_totalsize(initial_boot_params);
+        return sysfs_create_bin_file(firmware_kobj, &of_fdt_raw_attr);
 }
-module_init(of_flat_dt_debugfs_export_fdt);
+late_initcall(of_fdt_raw_init);
 #endif
 
 #endif /* CONFIG_OF_EARLY_FLATTREE */