efi_loader: move dtbdump.c, initrddump.c to lib/efi_loader

The tools dtbdump.efi and initrddump.efi are useful for Python testing even
if CONFIG_EFI_SELFTEST=n.

Don't clear the screen as it is incompatible with Python testing.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>

3 files changed, 1000 insertions, 0 deletions

diff --git a/lib/efi_loader/Makefile b/lib/efi_loader/Makefile
index b2c664d..befed71 100644
--- a/lib/efi_loader/Makefile
+++ b/lib/efi_loader/Makefile
@@ -14,12 +14,24 @@ CFLAGS_efi_boottime.o += \
   -DFW_PATCHLEVEL="0x$(PATCHLEVEL)"
 CFLAGS_helloworld.o := $(CFLAGS_EFI) -Os -ffreestanding
 CFLAGS_REMOVE_helloworld.o := $(CFLAGS_NON_EFI)
+CFLAGS_dtbdump.o := $(CFLAGS_EFI) -Os -ffreestanding
+CFLAGS_REMOVE_dtbdump.o := $(CFLAGS_NON_EFI)
+CFLAGS_initrddump_exit.o := $(CFLAGS_EFI) -Os -ffreestanding
+CFLAGS_REMOVE_initrddump.o := $(CFLAGS_NON_EFI)
 
 ifneq ($(CONFIG_CMD_BOOTEFI_HELLO_COMPILE),)
 always += helloworld.efi
 targets += helloworld.o
 endif
 
+ifeq ($(CONFIG_GENERATE_ACPI_TABLE),)
+always += dtbdump.efi
+endif
+
+ifdef CONFIG_EFI_LOAD_FILE2_INITRD
+always += initrddump.efi
+endif
+
 obj-$(CONFIG_CMD_BOOTEFI_HELLO) += helloworld_efi.o
 obj-$(CONFIG_CMD_BOOTEFI_BOOTMGR) += efi_bootmgr.o
 obj-y += efi_boottime.o
diff --git a/lib/efi_loader/dtbdump.c b/lib/efi_loader/dtbdump.c
new file mode 100644
index 0000000..3ce2a07
--- /dev/null
+++ b/lib/efi_loader/dtbdump.c
@@ -0,0 +1,539 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2020, Heinrich Schuchardt <xypron.glpk@gmx.de>
+ *
+ * dtbdump.efi saves the device tree provided as a configuration table
+ * to a file.
+ */
+
+#include <common.h>
+#include <efi_api.h>
+#include <efi_dt_fixup.h>
+#include <part.h>
+#include <linux/libfdt.h>
+
+#define BUFFER_SIZE 64
+#define ESC 0x17
+
+#define efi_size_in_pages(size) ((size + EFI_PAGE_MASK) >> EFI_PAGE_SHIFT)
+
+static struct efi_simple_text_output_protocol *cerr;
+static struct efi_simple_text_output_protocol *cout;
+static struct efi_simple_text_input_protocol *cin;
+static struct efi_boot_services *bs;
+static const efi_guid_t fdt_guid = EFI_FDT_GUID;
+static const efi_guid_t loaded_image_guid = EFI_LOADED_IMAGE_PROTOCOL_GUID;
+static const efi_guid_t guid_simple_file_system_protocol =
+					EFI_SIMPLE_FILE_SYSTEM_PROTOCOL_GUID;
+static efi_handle_t handle;
+static struct efi_system_table *systable;
+static const efi_guid_t efi_dt_fixup_protocol_guid = EFI_DT_FIXUP_PROTOCOL_GUID;
+static const efi_guid_t efi_file_info_guid = EFI_FILE_INFO_GUID;
+static const efi_guid_t efi_system_partition_guid = PARTITION_SYSTEM_GUID;
+
+/**
+ * print() - print string
+ *
+ * @string:	text
+ */
+static void print(u16 *string)
+{
+	cout->output_string(cout, string);
+}
+
+/**
+ * error() - print error string
+ *
+ * @string:	error text
+ */
+static void error(u16 *string)
+{
+	cout->set_attribute(cout, EFI_LIGHTRED | EFI_BACKGROUND_BLACK);
+	print(string);
+	cout->set_attribute(cout, EFI_LIGHTBLUE | EFI_BACKGROUND_BLACK);
+}
+
+/**
+ * efi_input_yn() - get answer to yes/no question
+ *
+ * Return:
+ * y or Y
+ *     EFI_SUCCESS
+ * n or N
+ *     EFI_ACCESS_DENIED
+ * ESC
+ *     EFI_ABORTED
+ */
+static efi_status_t efi_input_yn(void)
+{
+	struct efi_input_key key = {0};
+	efi_uintn_t index;
+	efi_status_t ret;
+
+	/* Drain the console input */
+	ret = cin->reset(cin, true);
+	for (;;) {
+		ret = bs->wait_for_event(1, &cin->wait_for_key, &index);
+		if (ret != EFI_SUCCESS)
+			continue;
+		ret = cin->read_key_stroke(cin, &key);
+		if (ret != EFI_SUCCESS)
+			continue;
+		switch (key.scan_code) {
+		case 0x17: /* Escape */
+			return EFI_ABORTED;
+		default:
+			break;
+		}
+		/* Convert to lower case */
+		switch (key.unicode_char | 0x20) {
+		case 'y':
+			return EFI_SUCCESS;
+		case 'n':
+			return EFI_ACCESS_DENIED;
+		default:
+			break;
+		}
+	}
+}
+
+/**
+ * efi_input() - read string from console
+ *
+ * @buffer:		input buffer
+ * @buffer_size:	buffer size
+ * Return:		status code
+ */
+static efi_status_t efi_input(u16 *buffer, efi_uintn_t buffer_size)
+{
+	struct efi_input_key key = {0};
+	efi_uintn_t index;
+	efi_uintn_t pos = 0;
+	u16 outbuf[2] = u" ";
+	efi_status_t ret;
+
+	/* Drain the console input */
+	ret = cin->reset(cin, true);
+	*buffer = 0;
+	for (;;) {
+		ret = bs->wait_for_event(1, &cin->wait_for_key, &index);
+		if (ret != EFI_SUCCESS)
+			continue;
+		ret = cin->read_key_stroke(cin, &key);
+		if (ret != EFI_SUCCESS)
+			continue;
+		switch (key.scan_code) {
+		case 0x17: /* Escape */
+			print(u"\r\nAborted\r\n");
+			return EFI_ABORTED;
+		default:
+			break;
+		}
+		switch (key.unicode_char) {
+		case 0x08: /* Backspace */
+			if (pos) {
+				buffer[pos--] = 0;
+				print(u"\b \b");
+			}
+			break;
+		case 0x0a: /* Linefeed */
+		case 0x0d: /* Carriage return */
+			print(u"\r\n");
+			return EFI_SUCCESS;
+		default:
+			break;
+		}
+		/* Ignore surrogate codes */
+		if (key.unicode_char >= 0xD800 && key.unicode_char <= 0xDBFF)
+			continue;
+		if (key.unicode_char >= 0x20 &&
+		    pos < buffer_size - 1) {
+			*outbuf = key.unicode_char;
+			buffer[pos++] = key.unicode_char;
+			buffer[pos] = 0;
+			print(outbuf);
+		}
+	}
+}
+
+/*
+ * Convert FDT value to host endianness.
+ *
+ * @val		FDT value
+ * Return:	converted value
+ */
+static u32 f2h(fdt32_t val)
+{
+	char *buf = (char *)&val;
+	char i;
+
+	/* Swap the bytes */
+	i = buf[0]; buf[0] = buf[3]; buf[3] = i;
+	i = buf[1]; buf[1] = buf[2]; buf[2] = i;
+	return *(u32 *)buf;
+}
+
+/**
+ * get_dtb() - get device tree
+ *
+ * @systable:	system table
+ * Return:	device tree or NULL
+ */
+void *get_dtb(struct efi_system_table *systable)
+{
+	void *dtb = NULL;
+	efi_uintn_t i;
+
+	for (i = 0; i < systable->nr_tables; ++i) {
+		if (!memcmp(&systable->tables[i].guid, &fdt_guid,
+			    sizeof(efi_guid_t))) {
+			dtb = systable->tables[i].table;
+			break;
+		}
+	}
+	return dtb;
+}
+
+/**
+ * skip_whitespace() - skip over leading whitespace
+ *
+ * @pos:	UTF-16 string
+ * Return:	pointer to first non-whitespace
+ */
+u16 *skip_whitespace(u16 *pos)
+{
+	for (; *pos && *pos <= 0x20; ++pos)
+		;
+	return pos;
+}
+
+/**
+ * starts_with() - check if @string starts with @keyword
+ *
+ * @string:	string to search for keyword
+ * @keyword:	keyword to be searched
+ * Return:	true fi @string starts with the keyword
+ */
+bool starts_with(u16 *string, u16 *keyword)
+{
+	for (; *keyword; ++string, ++keyword) {
+		if (*string != *keyword)
+			return false;
+	}
+	return true;
+}
+
+/**
+ * do_help() - print help
+ */
+void do_help(void)
+{
+	error(u"load <dtb> - load device-tree from file\r\n");
+	error(u"save <dtb> - save device-tree to file\r\n");
+	error(u"exit       - exit the shell\r\n");
+}
+
+/**
+ * open_file_system() - open simple file system protocol
+ *
+ * file_system:	interface of the simple file system protocol
+ * Return:	status code
+ */
+static efi_status_t
+open_file_system(struct efi_simple_file_system_protocol **file_system)
+{
+	struct efi_loaded_image *loaded_image;
+	efi_status_t ret;
+	efi_handle_t *handle_buffer = NULL;
+	efi_uintn_t count;
+
+	ret = bs->open_protocol(handle, &loaded_image_guid,
+				(void **)&loaded_image, NULL, NULL,
+				EFI_OPEN_PROTOCOL_GET_PROTOCOL);
+	if (ret != EFI_SUCCESS) {
+		error(u"Loaded image protocol not found\r\n");
+		return ret;
+	}
+
+	/* Open the simple file system protocol on the same partition */
+	ret = bs->open_protocol(loaded_image->device_handle,
+				&guid_simple_file_system_protocol,
+				(void **)file_system, NULL, NULL,
+				EFI_OPEN_PROTOCOL_GET_PROTOCOL);
+	if (ret == EFI_SUCCESS)
+		return ret;
+
+	/* Open the simple file system protocol on the UEFI system partition */
+	ret = bs->locate_handle_buffer(BY_PROTOCOL, &efi_system_partition_guid,
+				       NULL, &count, &handle_buffer);
+	if (ret == EFI_SUCCESS && handle_buffer)
+		ret = bs->open_protocol(handle_buffer[0],
+					&guid_simple_file_system_protocol,
+					(void **)file_system, NULL, NULL,
+					EFI_OPEN_PROTOCOL_GET_PROTOCOL);
+	if (ret != EFI_SUCCESS)
+		error(u"Failed to open simple file system protocol\r\n");
+	if (handle)
+		bs->free_pool(handle_buffer);
+
+	return ret;
+}
+
+/**
+ * do_load() - load and install device-tree
+ *
+ * @filename:	file name
+ * Return:	status code
+ */
+efi_status_t do_load(u16 *filename)
+{
+	struct efi_dt_fixup_protocol *dt_fixup_prot;
+	struct efi_simple_file_system_protocol *file_system;
+	struct efi_file_handle *root = NULL, *file = NULL;
+	u64 addr = 0;
+	struct efi_file_info *info;
+	struct fdt_header *dtb;
+	efi_uintn_t buffer_size;
+	efi_uintn_t pages;
+	efi_status_t ret, ret2;
+
+	ret = bs->locate_protocol(&efi_dt_fixup_protocol_guid, NULL,
+				  (void **)&dt_fixup_prot);
+	if (ret != EFI_SUCCESS) {
+		error(u"Device-tree fix-up protocol not found\r\n");
+		return ret;
+	}
+
+	filename = skip_whitespace(filename);
+
+	ret = open_file_system(&file_system);
+	if (ret != EFI_SUCCESS)
+		goto out;
+
+	/* Open volume */
+	ret = file_system->open_volume(file_system, &root);
+	if (ret != EFI_SUCCESS) {
+		error(u"Failed to open volume\r\n");
+		goto out;
+	}
+
+	/* Open file */
+	ret = root->open(root, &file, filename, EFI_FILE_MODE_READ, 0);
+	if (ret != EFI_SUCCESS) {
+		error(u"File not found\r\n");
+		goto out;
+	}
+	/* Get file size */
+	buffer_size = 0;
+	ret = file->getinfo(file, &efi_file_info_guid, &buffer_size, NULL);
+	if (ret != EFI_BUFFER_TOO_SMALL) {
+		error(u"Can't get file info size\r\n");
+		goto out;
+	}
+	ret = bs->allocate_pool(EFI_LOADER_DATA, buffer_size, (void **)&info);
+	if (ret != EFI_SUCCESS) {
+		error(u"Out of memory\r\n");
+		goto out;
+	}
+	ret = file->getinfo(file, &efi_file_info_guid, &buffer_size, info);
+	if (ret != EFI_SUCCESS) {
+		error(u"Can't get file info\r\n");
+		goto out;
+	}
+	buffer_size = info->file_size;
+	pages = efi_size_in_pages(buffer_size);
+	ret = bs->free_pool(info);
+	if (ret != EFI_SUCCESS)
+		error(u"Can't free memory pool\r\n");
+	/* Read file */
+	ret = bs->allocate_pages(EFI_ALLOCATE_ANY_PAGES,
+				 EFI_ACPI_RECLAIM_MEMORY,
+				 pages, &addr);
+	if (ret != EFI_SUCCESS) {
+		error(u"Out of memory\r\n");
+		goto out;
+	}
+	dtb = (struct fdt_header *)(uintptr_t)addr;
+	ret = file->read(file, &buffer_size, dtb);
+	if (ret != EFI_SUCCESS) {
+		error(u"Can't read file\r\n");
+		goto out;
+	}
+	/* Fixup file, expecting EFI_BUFFER_TOO_SMALL */
+	ret = dt_fixup_prot->fixup(dt_fixup_prot, dtb, &buffer_size,
+				   EFI_DT_APPLY_FIXUPS | EFI_DT_RESERVE_MEMORY |
+				   EFI_DT_INSTALL_TABLE);
+	if (ret == EFI_BUFFER_TOO_SMALL) {
+		/* Read file into larger buffer */
+		ret = bs->free_pages(addr, pages);
+		if (ret != EFI_SUCCESS)
+			error(u"Can't free memory pages\r\n");
+		pages = efi_size_in_pages(buffer_size);
+		ret = bs->allocate_pages(EFI_ALLOCATE_ANY_PAGES,
+					 EFI_ACPI_RECLAIM_MEMORY,
+					 pages, &addr);
+		if (ret != EFI_SUCCESS) {
+			error(u"Out of memory\r\n");
+			goto out;
+		}
+		dtb = (struct fdt_header *)(uintptr_t)addr;
+		ret = file->setpos(file, 0);
+		if (ret != EFI_SUCCESS) {
+			error(u"Can't position file\r\n");
+			goto out;
+		}
+		ret = file->read(file, &buffer_size, dtb);
+		if (ret != EFI_SUCCESS) {
+			error(u"Can't read file\r\n");
+			goto out;
+		}
+		buffer_size = pages << EFI_PAGE_SHIFT;
+		ret = dt_fixup_prot->fixup(
+				dt_fixup_prot, dtb, &buffer_size,
+				EFI_DT_APPLY_FIXUPS | EFI_DT_RESERVE_MEMORY |
+				EFI_DT_INSTALL_TABLE);
+	}
+	if (ret == EFI_SUCCESS)
+		print(u"device-tree installed\r\n");
+	else
+		error(u"Device-tree fix-up failed\r\n");
+out:
+	if (addr) {
+		ret2 = bs->free_pages(addr, pages);
+		if (ret2 != EFI_SUCCESS)
+			error(u"Can't free memory pages\r\n");
+	}
+	if (file) {
+		ret2 = file->close(file);
+		if (ret2 != EFI_SUCCESS)
+			error(u"Can't close file\r\n");
+	}
+	if (root) {
+		ret2 = root->close(root);
+		if (ret2 != EFI_SUCCESS)
+			error(u"Can't close volume\r\n");
+	}
+	return ret;
+}
+
+/**
+ * do_save() - save current device-tree
+ *
+ * @filename:	file name
+ * Return:	status code
+ */
+efi_status_t do_save(u16 *filename)
+{
+	struct efi_simple_file_system_protocol *file_system;
+	efi_uintn_t dtb_size;
+	struct efi_file_handle *root, *file;
+	struct fdt_header *dtb;
+	efi_uintn_t ret;
+
+	dtb = get_dtb(systable);
+	if (!dtb) {
+		error(u"DTB not found\r\n");
+		return EFI_NOT_FOUND;
+	}
+	if (f2h(dtb->magic) != FDT_MAGIC) {
+		error(u"Wrong device tree magic\r\n");
+		return EFI_NOT_FOUND;
+	}
+	dtb_size = f2h(dtb->totalsize);
+
+	filename = skip_whitespace(filename);
+
+	ret = open_file_system(&file_system);
+	if (ret != EFI_SUCCESS)
+		return ret;
+
+	/* Open volume */
+	ret = file_system->open_volume(file_system, &root);
+	if (ret != EFI_SUCCESS) {
+		error(u"Failed to open volume\r\n");
+		return ret;
+	}
+	/* Check if file already exists */
+	ret = root->open(root, &file, filename, EFI_FILE_MODE_READ, 0);
+	if (ret == EFI_SUCCESS) {
+		file->close(file);
+		print(u"Overwrite existing file (y/n)? ");
+		ret = efi_input_yn();
+		print(u"\r\n");
+		if (ret != EFI_SUCCESS) {
+			root->close(root);
+			error(u"Aborted by user\r\n");
+			return ret;
+		}
+	}
+
+	/* Create file */
+	ret = root->open(root, &file, filename,
+			 EFI_FILE_MODE_READ | EFI_FILE_MODE_WRITE |
+			 EFI_FILE_MODE_CREATE, EFI_FILE_ARCHIVE);
+	if (ret == EFI_SUCCESS) {
+		/* Write file */
+		ret = file->write(file, &dtb_size, dtb);
+		if (ret != EFI_SUCCESS)
+			error(u"Failed to write file\r\n");
+		file->close(file);
+	} else {
+		error(u"Failed to open file\r\n");
+	}
+	root->close(root);
+
+	if (ret == EFI_SUCCESS) {
+		print(filename);
+		print(u" written\r\n");
+	}
+
+	return ret;
+}
+
+/**
+ * efi_main() - entry point of the EFI application.
+ *
+ * @handle:	handle of the loaded image
+ * @systab:	system table
+ * Return:	status code
+ */
+efi_status_t EFIAPI efi_main(efi_handle_t image_handle,
+			     struct efi_system_table *systab)
+{
+	handle = image_handle;
+	systable = systab;
+	cerr = systable->std_err;
+	cout = systable->con_out;
+	cin = systable->con_in;
+	bs = systable->boottime;
+
+	cout->set_attribute(cout, EFI_LIGHTBLUE | EFI_BACKGROUND_BLACK);
+	cout->clear_screen(cout);
+	cout->set_attribute(cout, EFI_WHITE | EFI_BACKGROUND_BLACK);
+	print(u"DTB Dump\r\n========\r\n\r\n");
+	cout->set_attribute(cout, EFI_LIGHTBLUE | EFI_BACKGROUND_BLACK);
+
+	for (;;) {
+		u16 command[BUFFER_SIZE];
+		u16 *pos;
+		efi_uintn_t ret;
+
+		print(u"=> ");
+		ret = efi_input(command, sizeof(command));
+		if (ret == EFI_ABORTED)
+			break;
+		pos = skip_whitespace(command);
+		if (starts_with(pos, u"exit"))
+			break;
+		else if (starts_with(pos, u"load "))
+			do_load(pos + 5);
+		else if (starts_with(pos, u"save "))
+			do_save(pos + 5);
+		else
+			do_help();
+	}
+
+	cout->set_attribute(cout, EFI_LIGHTGRAY | EFI_BACKGROUND_BLACK);
+	cout->clear_screen(cout);
+	return EFI_SUCCESS;
+}
diff --git a/lib/efi_loader/initrddump.c b/lib/efi_loader/initrddump.c
new file mode 100644
index 0000000..7de43bc
--- /dev/null
+++ b/lib/efi_loader/initrddump.c
@@ -0,0 +1,449 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2020, Heinrich Schuchardt <xypron.glpk@gmx.de>
+ *
+ * initrddump.efi saves the initial RAM disk provided via the
+ * EFI_LOAD_FILE2_PROTOCOL.
+ */
+
+#include <common.h>
+#include <efi_api.h>
+#include <efi_load_initrd.h>
+
+#define BUFFER_SIZE 64
+#define ESC 0x17
+
+#define efi_size_in_pages(size) (((size) + EFI_PAGE_MASK) >> EFI_PAGE_SHIFT)
+
+static struct efi_system_table *systable;
+static struct efi_boot_services *bs;
+static struct efi_simple_text_output_protocol *cerr;
+static struct efi_simple_text_output_protocol *cout;
+static struct efi_simple_text_input_protocol *cin;
+static const efi_guid_t loaded_image_guid = EFI_LOADED_IMAGE_PROTOCOL_GUID;
+static const efi_guid_t guid_simple_file_system_protocol =
+					EFI_SIMPLE_FILE_SYSTEM_PROTOCOL_GUID;
+static const efi_guid_t load_file2_guid = EFI_LOAD_FILE2_PROTOCOL_GUID;
+static efi_handle_t handle;
+
+/*
+ * Device path defined by Linux to identify the handle providing the
+ * EFI_LOAD_FILE2_PROTOCOL used for loading the initial ramdisk.
+ */
+static const struct efi_initrd_dp initrd_dp = {
+	.vendor = {
+		{
+		   DEVICE_PATH_TYPE_MEDIA_DEVICE,
+		   DEVICE_PATH_SUB_TYPE_VENDOR_PATH,
+		   sizeof(initrd_dp.vendor),
+		},
+		EFI_INITRD_MEDIA_GUID,
+	},
+	.end = {
+		DEVICE_PATH_TYPE_END,
+		DEVICE_PATH_SUB_TYPE_END,
+		sizeof(initrd_dp.end),
+	}
+};
+
+/**
+ * print() - print string
+ *
+ * @string:	text
+ */
+static void print(u16 *string)
+{
+	cout->output_string(cout, string);
+}
+
+/**
+ * error() - print error string
+ *
+ * @string:	error text
+ */
+static void error(u16 *string)
+{
+	cout->set_attribute(cout, EFI_LIGHTRED | EFI_BACKGROUND_BLACK);
+	print(string);
+	cout->set_attribute(cout, EFI_LIGHTBLUE | EFI_BACKGROUND_BLACK);
+}
+
+/*
+ * printx() - print hexadecimal number
+ *
+ * @val:	value to print;
+ * @prec:	minimum number of digits to print
+ */
+static void printx(u64 val, u32 prec)
+{
+	int i;
+	u16 c;
+	u16 buf[16];
+	u16 *pos = buf;
+
+	for (i = 2 * sizeof(val) - 1; i >= 0; --i) {
+		c = (val >> (4 * i)) & 0x0f;
+		if (c || pos != buf || !i || i < prec) {
+			c += '0';
+			if (c > '9')
+				c += 'a' - '9' - 1;
+			*pos++ = c;
+		}
+	}
+	*pos = 0;
+	print(buf);
+}
+
+/**
+ * efi_input_yn() - get answer to yes/no question
+ *
+ * Return:
+ * y or Y
+ *     EFI_SUCCESS
+ * n or N
+ *     EFI_ACCESS_DENIED
+ * ESC
+ *     EFI_ABORTED
+ */
+static efi_status_t efi_input_yn(void)
+{
+	struct efi_input_key key = {0};
+	efi_uintn_t index;
+	efi_status_t ret;
+
+	/* Drain the console input */
+	ret = cin->reset(cin, true);
+	for (;;) {
+		ret = bs->wait_for_event(1, &cin->wait_for_key, &index);
+		if (ret != EFI_SUCCESS)
+			continue;
+		ret = cin->read_key_stroke(cin, &key);
+		if (ret != EFI_SUCCESS)
+			continue;
+		switch (key.scan_code) {
+		case 0x17: /* Escape */
+			return EFI_ABORTED;
+		default:
+			break;
+		}
+		/* Convert to lower case */
+		switch (key.unicode_char | 0x20) {
+		case 'y':
+			return EFI_SUCCESS;
+		case 'n':
+			return EFI_ACCESS_DENIED;
+		default:
+			break;
+		}
+	}
+}
+
+/**
+ * efi_input() - read string from console
+ *
+ * @buffer:		input buffer
+ * @buffer_size:	buffer size
+ * Return:		status code
+ */
+static efi_status_t efi_input(u16 *buffer, efi_uintn_t buffer_size)
+{
+	struct efi_input_key key = {0};
+	efi_uintn_t index;
+	efi_uintn_t pos = 0;
+	u16 outbuf[2] = u" ";
+	efi_status_t ret;
+
+	/* Drain the console input */
+	ret = cin->reset(cin, true);
+	*buffer = 0;
+	for (;;) {
+		ret = bs->wait_for_event(1, &cin->wait_for_key, &index);
+		if (ret != EFI_SUCCESS)
+			continue;
+		ret = cin->read_key_stroke(cin, &key);
+		if (ret != EFI_SUCCESS)
+			continue;
+		switch (key.scan_code) {
+		case 0x17: /* Escape */
+			print(u"\r\nAborted\r\n");
+			return EFI_ABORTED;
+		default:
+			break;
+		}
+		switch (key.unicode_char) {
+		case 0x08: /* Backspace */
+			if (pos) {
+				buffer[pos--] = 0;
+				print(u"\b \b");
+			}
+			break;
+		case 0x0a: /* Linefeed */
+		case 0x0d: /* Carriage return */
+			print(u"\r\n");
+			return EFI_SUCCESS;
+		default:
+			break;
+		}
+		/* Ignore surrogate codes */
+		if (key.unicode_char >= 0xD800 && key.unicode_char <= 0xDBFF)
+			continue;
+		if (key.unicode_char >= 0x20 &&
+		    pos < buffer_size - 1) {
+			*outbuf = key.unicode_char;
+			buffer[pos++] = key.unicode_char;
+			buffer[pos] = 0;
+			print(outbuf);
+		}
+	}
+}
+
+/**
+ * skip_whitespace() - skip over leading whitespace
+ *
+ * @pos:	UTF-16 string
+ * Return:	pointer to first non-whitespace
+ */
+static u16 *skip_whitespace(u16 *pos)
+{
+	for (; *pos && *pos <= 0x20; ++pos)
+		;
+	return pos;
+}
+
+/**
+ * starts_with() - check if @string starts with @keyword
+ *
+ * @string:	string to search for keyword
+ * @keyword:	keyword to be searched
+ * Return:	true fi @string starts with the keyword
+ */
+static bool starts_with(u16 *string, u16 *keyword)
+{
+	for (; *keyword; ++string, ++keyword) {
+		if (*string != *keyword)
+			return false;
+	}
+	return true;
+}
+
+/**
+ * do_help() - print help
+ */
+static void do_help(void)
+{
+	error(u"load          - show length and CRC32 of initial RAM disk\r\n");
+	error(u"save <initrd> - save initial RAM disk to file\r\n");
+	error(u"exit          - exit the shell\r\n");
+}
+
+/**
+ * get_initrd() - read initial RAM disk via EFI_LOAD_FILE2_PROTOCOL
+ *
+ * @initrd:		on return buffer with initial RAM disk
+ * @initrd_size:	size of initial RAM disk
+ * Return:		status code
+ */
+static efi_status_t get_initrd(void **initrd, efi_uintn_t *initrd_size)
+{
+	struct efi_device_path *dp = (struct efi_device_path *)&initrd_dp;
+	struct efi_load_file_protocol *load_file2_prot;
+	u64 buffer;
+	efi_handle_t handle;
+	efi_status_t ret;
+
+	*initrd = NULL;
+	*initrd_size = 0;
+	ret = bs->locate_device_path(&load_file2_guid, &dp, &handle);
+	if (ret != EFI_SUCCESS) {
+		error(u"Load File2 protocol not found\r\n");
+		return ret;
+	}
+	ret = bs->handle_protocol(handle, &load_file2_guid,
+				 (void **)&load_file2_prot);
+	ret = load_file2_prot->load_file(load_file2_prot, dp, false,
+					 initrd_size, NULL);
+	if (ret != EFI_BUFFER_TOO_SMALL) {
+		error(u"Load File2 protocol does not provide file length\r\n");
+		return EFI_LOAD_ERROR;
+	}
+	ret = bs->allocate_pages(EFI_ALLOCATE_ANY_PAGES, EFI_LOADER_DATA,
+				 efi_size_in_pages(*initrd_size), &buffer);
+	if (ret != EFI_SUCCESS) {
+		error(u"Out of memory\r\n");
+		return ret;
+	}
+	*initrd = (void *)(uintptr_t)buffer;
+	ret = load_file2_prot->load_file(load_file2_prot, dp, false,
+					 initrd_size, *initrd);
+	if (ret != EFI_SUCCESS) {
+		error(u"Load File2 protocol failed to provide file\r\n");
+		bs->free_pages(buffer, efi_size_in_pages(*initrd_size));
+		return EFI_LOAD_ERROR;
+	}
+	return ret;
+}
+
+/**
+ * do_load() - load initial RAM disk and display CRC32 and length
+ *
+ * @filename:	file name
+ * Return:	status code
+ */
+static efi_status_t do_load(void)
+{
+	void *initrd;
+	efi_uintn_t initrd_size;
+	u32 crc32;
+	efi_uintn_t ret;
+
+	ret =  get_initrd(&initrd, &initrd_size);
+	if (ret != EFI_SUCCESS)
+		return ret;
+	print(u"length: 0x");
+	printx(initrd_size, 1);
+	print(u"\r\n");
+
+	ret = bs->calculate_crc32(initrd, initrd_size, &crc32);
+	if (ret != EFI_SUCCESS) {
+		error(u"Calculating CRC32 failed\r\n");
+		return EFI_LOAD_ERROR;
+	}
+	print(u"crc32: 0x");
+	printx(crc32, 8);
+	print(u"\r\n");
+
+	return EFI_SUCCESS;
+}
+
+/**
+ * do_save() - save initial RAM disk
+ *
+ * @filename:	file name
+ * Return:	status code
+ */
+static efi_status_t do_save(u16 *filename)
+{
+	struct efi_loaded_image *loaded_image;
+	struct efi_simple_file_system_protocol *file_system;
+	struct efi_file_handle *root, *file;
+	void *initrd;
+	efi_uintn_t initrd_size;
+	efi_uintn_t ret;
+
+	ret = get_initrd(&initrd, &initrd_size);
+	if (ret != EFI_SUCCESS)
+		return ret;
+
+	filename = skip_whitespace(filename);
+
+	ret = bs->open_protocol(handle, &loaded_image_guid,
+				(void **)&loaded_image, NULL, NULL,
+				EFI_OPEN_PROTOCOL_GET_PROTOCOL);
+	if (ret != EFI_SUCCESS) {
+		error(u"Loaded image protocol not found\r\n");
+		goto out;
+	}
+
+	/* Open the simple file system protocol */
+	ret = bs->open_protocol(loaded_image->device_handle,
+				&guid_simple_file_system_protocol,
+				(void **)&file_system, NULL, NULL,
+				EFI_OPEN_PROTOCOL_GET_PROTOCOL);
+	if (ret != EFI_SUCCESS) {
+		error(u"Failed to open simple file system protocol\r\n");
+		goto out;
+	}
+
+	/* Open volume */
+	ret = file_system->open_volume(file_system, &root);
+	if (ret != EFI_SUCCESS) {
+		error(u"Failed to open volume\r\n");
+		goto out;
+	}
+	/* Check if file already exists */
+	ret = root->open(root, &file, filename, EFI_FILE_MODE_READ, 0);
+	if (ret == EFI_SUCCESS) {
+		file->close(file);
+		print(u"Overwrite existing file (y/n)? ");
+		ret = efi_input_yn();
+		print(u"\r\n");
+		if (ret != EFI_SUCCESS) {
+			root->close(root);
+			error(u"Aborted by user\r\n");
+			goto out;
+		}
+	}
+
+	/* Create file */
+	ret = root->open(root, &file, filename,
+			 EFI_FILE_MODE_READ | EFI_FILE_MODE_WRITE |
+			 EFI_FILE_MODE_CREATE, EFI_FILE_ARCHIVE);
+	if (ret == EFI_SUCCESS) {
+		/* Write file */
+		ret = file->write(file, &initrd_size, initrd);
+		if (ret != EFI_SUCCESS) {
+			error(u"Failed to write file\r\n");
+		} else {
+			print(filename);
+			print(u" written\r\n");
+		}
+		file->close(file);
+	} else {
+		error(u"Failed to open file\r\n");
+	}
+	root->close(root);
+
+out:
+	if (initrd)
+		bs->free_pages((uintptr_t)initrd,
+			       efi_size_in_pages(initrd_size));
+	return ret;
+}
+
+/**
+ * efi_main() - entry point of the EFI application.
+ *
+ * @handle:	handle of the loaded image
+ * @systab:	system table
+ * Return:	status code
+ */
+efi_status_t EFIAPI efi_main(efi_handle_t image_handle,
+			     struct efi_system_table *systab)
+{
+	handle = image_handle;
+	systable = systab;
+	cerr = systable->std_err;
+	cout = systable->con_out;
+	cin = systable->con_in;
+	bs = systable->boottime;
+
+	cout->set_attribute(cout, EFI_LIGHTBLUE | EFI_BACKGROUND_BLACK);
+	cout->clear_screen(cout);
+	cout->set_attribute(cout, EFI_WHITE | EFI_BACKGROUND_BLACK);
+	print(u"INITRD Dump\r\n===========\r\n\r\n");
+	cout->set_attribute(cout, EFI_LIGHTBLUE | EFI_BACKGROUND_BLACK);
+
+	for (;;) {
+		u16 command[BUFFER_SIZE];
+		u16 *pos;
+		efi_uintn_t ret;
+
+		print(u"=> ");
+		ret = efi_input(command, sizeof(command));
+		if (ret == EFI_ABORTED)
+			break;
+		pos = skip_whitespace(command);
+		if (starts_with(pos, u"exit"))
+			break;
+		else if (starts_with(pos, u"load"))
+			do_load();
+		else if (starts_with(pos, u"save "))
+			do_save(pos + 5);
+		else
+			do_help();
+	}
+
+	cout->set_attribute(cout, EFI_LIGHTGRAY | EFI_BACKGROUND_BLACK);
+	cout->clear_screen(cout);
+	return EFI_SUCCESS;
+}