1 files changed, 83 insertions, 0 deletions
diff --git a/arch/um/kernel/initrd.c b/arch/um/kernel/initrd.c
new file mode 100644
index 000000000..c1981ffb7
--- /dev/null
+++ b/arch/um/kernel/initrd.c
@@ -0,0 +1,83 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
+ */
+
+#include <linux/init.h>
+#include <linux/memblock.h>
+#include <linux/initrd.h>
+#include <asm/types.h>
+#include <init.h>
+#include <os.h>
+
+/* Changed by uml_initrd_setup, which is a setup */
+static char *initrd __initdata = NULL;
+static int load_initrd(char *filename, void *buf, int size);
+
+int __init read_initrd(void)
+{
+	void *area;
+	long long size;
+	int err;
+
+	if (initrd == NULL)
+		return 0;
+
+	err = os_file_size(initrd, &size);
+	if (err)
+		return 0;
+
+	/*
+	 * This is necessary because alloc_bootmem craps out if you
+	 * ask for no memory.
+	 */
+	if (size == 0) {
+		printk(KERN_ERR "\"%s\" is a zero-size initrd\n", initrd);
+		return 0;
+	}
+
+	area = memblock_alloc(size, SMP_CACHE_BYTES);
+	if (!area)
+		panic("%s: Failed to allocate %llu bytes\n", __func__, size);
+
+	if (load_initrd(initrd, area, size) == -1)
+		return 0;
+
+	initrd_start = (unsigned long) area;
+	initrd_end = initrd_start + size;
+	return 0;
+}
+
+static int __init uml_initrd_setup(char *line, int *add)
+{
+	initrd = line;
+	return 0;
+}
+
+__uml_setup("initrd=", uml_initrd_setup,
+"initrd=<initrd image>\n"
+"    This is used to boot UML from an initrd image.  The argument is the\n"
+"    name of the file containing the image.\n\n"
+);
+
+static int load_initrd(char *filename, void *buf, int size)
+{
+	int fd, n;
+
+	fd = os_open_file(filename, of_read(OPENFLAGS()), 0);
+	if (fd < 0) {
+		printk(KERN_ERR "Opening '%s' failed - err = %d\n", filename,
+		       -fd);
+		return -1;
+	}
+	n = os_read_file(fd, buf, size);
+	if (n != size) {
+		printk(KERN_ERR "Read of %d bytes from '%s' failed, "
+		       "err = %d\n", size,
+		       filename, -n);
+		return -1;
+	}
+
+	os_close_file(fd);
+	return 0;
+}