1 files changed, 75 insertions, 0 deletions
diff --git a/arch/arm/kernel/atags_proc.c b/arch/arm/kernel/atags_proc.c
new file mode 100644
index 000000000..5a3379055
--- /dev/null
+++ b/arch/arm/kernel/atags_proc.c
@@ -0,0 +1,75 @@
+#include <linux/slab.h>
+#include <linux/proc_fs.h>
+#include <asm/setup.h>
+#include <asm/types.h>
+#include <asm/page.h>
+
+struct buffer {
+	size_t size;
+	char data[];
+};
+
+static ssize_t atags_read(struct file *file, char __user *buf,
+			  size_t count, loff_t *ppos)
+{
+	struct buffer *b = PDE_DATA(file_inode(file));
+	return simple_read_from_buffer(buf, count, ppos, b->data, b->size);
+}
+
+static const struct file_operations atags_fops = {
+	.read = atags_read,
+	.llseek = default_llseek,
+};
+
+#define BOOT_PARAMS_SIZE 1536
+static char __initdata atags_copy[BOOT_PARAMS_SIZE];
+
+void __init save_atags(const struct tag *tags)
+{
+	memcpy(atags_copy, tags, sizeof(atags_copy));
+}
+
+static int __init init_atags_procfs(void)
+{
+	/*
+	 * This cannot go into save_atags() because kmalloc and proc don't work
+	 * yet when it is called.
+	 */
+	struct proc_dir_entry *tags_entry;
+	struct tag *tag = (struct tag *)atags_copy;
+	struct buffer *b;
+	size_t size;
+
+	if (tag->hdr.tag != ATAG_CORE) {
+		pr_info("No ATAGs?");
+		return -EINVAL;
+	}
+
+	for (; tag->hdr.size; tag = tag_next(tag))
+		;
+
+	/* include the terminating ATAG_NONE */
+	size = (char *)tag - atags_copy + sizeof(struct tag_header);
+
+	WARN_ON(tag->hdr.tag != ATAG_NONE);
+
+	b = kmalloc(sizeof(*b) + size, GFP_KERNEL);
+	if (!b)
+		goto nomem;
+
+	b->size = size;
+	memcpy(b->data, atags_copy, size);
+
+	tags_entry = proc_create_data("atags", 0400, NULL, &atags_fops, b);
+	if (!tags_entry)
+		goto nomem;
+
+	return 0;
+
+nomem:
+	kfree(b);
+	pr_err("Exporting ATAGs: not enough memory\n");
+
+	return -ENOMEM;
+}
+arch_initcall(init_atags_procfs);