From 849369d6c66d3054688672f97d31fceb8e8230fb Mon Sep 17 00:00:00 2001
From: root <root@artemis.panaceas.org>
Date: Fri, 25 Dec 2015 04:40:36 +0000
Subject: initial_commit

---
 arch/arm/kernel/atags.c | 83 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 83 insertions(+)
 create mode 100644 arch/arm/kernel/atags.c

(limited to 'arch/arm/kernel/atags.c')

diff --git a/arch/arm/kernel/atags.c b/arch/arm/kernel/atags.c
new file mode 100644
index 00000000..42a1a141
--- /dev/null
+++ b/arch/arm/kernel/atags.c
@@ -0,0 +1,83 @@
+#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 int
+read_buffer(char* page, char** start, off_t off, int count,
+	int* eof, void* data)
+{
+	struct buffer *buffer = (struct buffer *)data;
+
+	if (off >= buffer->size) {
+		*eof = 1;
+		return 0;
+	}
+
+	count = min((int) (buffer->size - off), count);
+
+	memcpy(page, &buffer->data[off], count);
+
+	return count;
+}
+
+#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) {
+		printk(KERN_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 = create_proc_read_entry("atags", 0400,
+			NULL, read_buffer, b);
+
+	if (!tags_entry)
+		goto nomem;
+
+	return 0;
+
+nomem:
+	kfree(b);
+	printk(KERN_ERR "Exporting ATAGs: not enough memory\n");
+
+	return -ENOMEM;
+}
+arch_initcall(init_atags_procfs);
-- 
cgit v1.2.3