1 files changed, 282 insertions, 0 deletions
diff --git a/lib/efi_loader/efi_bootmgr.c b/lib/efi_loader/efi_bootmgr.c
new file mode 100644
index 00000000..2ea21448
--- /dev/null
+++ b/lib/efi_loader/efi_bootmgr.c
@@ -0,0 +1,282 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ *  EFI boot manager
+ *
+ *  Copyright (c) 2017 Rob Clark
+ */
+
+#include <common.h>
+#include <charset.h>
+#include <malloc.h>
+#include <efi_loader.h>
+#include <asm/unaligned.h>
+
+static const struct efi_boot_services *bs;
+static const struct efi_runtime_services *rs;
+
+/*
+ * bootmgr implements the logic of trying to find a payload to boot
+ * based on the BootOrder + BootXXXX variables, and then loading it.
+ *
+ * TODO detecting a special key held (f9?) and displaying a boot menu
+ * like you would get on a PC would be clever.
+ *
+ * TODO if we had a way to write and persist variables after the OS
+ * has started, we'd also want to check OsIndications to see if we
+ * should do normal or recovery boot.
+ */
+
+
+/**
+ * efi_deserialize_load_option() - parse serialized data
+ *
+ * Parse serialized data describing a load option and transform it to the
+ * efi_load_option structure.
+ *
+ * @lo:		pointer to target
+ * @data:	serialized data
+ */
+void efi_deserialize_load_option(struct efi_load_option *lo, u8 *data)
+{
+	lo->attributes = get_unaligned_le32(data);
+	data += sizeof(u32);
+
+	lo->file_path_length = get_unaligned_le16(data);
+	data += sizeof(u16);
+
+	/* FIXME */
+	lo->label = (u16 *)data;
+	data += (u16_strlen(lo->label) + 1) * sizeof(u16);
+
+	/* FIXME */
+	lo->file_path = (struct efi_device_path *)data;
+	data += lo->file_path_length;
+
+	lo->optional_data = data;
+}
+
+/**
+ * efi_serialize_load_option() - serialize load option
+ *
+ * Serialize efi_load_option structure into byte stream for BootXXXX.
+ *
+ * @data:	buffer for serialized data
+ * @lo:		load option
+ * Return:	size of allocated buffer
+ */
+unsigned long efi_serialize_load_option(struct efi_load_option *lo, u8 **data)
+{
+	unsigned long label_len;
+	unsigned long size;
+	u8 *p;
+
+	label_len = (u16_strlen(lo->label) + 1) * sizeof(u16);
+
+	/* total size */
+	size = sizeof(lo->attributes);
+	size += sizeof(lo->file_path_length);
+	size += label_len;
+	size += lo->file_path_length;
+	if (lo->optional_data)
+		size += (utf8_utf16_strlen((const char *)lo->optional_data)
+					   + 1) * sizeof(u16);
+	p = malloc(size);
+	if (!p)
+		return 0;
+
+	/* copy data */
+	*data = p;
+	memcpy(p, &lo->attributes, sizeof(lo->attributes));
+	p += sizeof(lo->attributes);
+
+	memcpy(p, &lo->file_path_length, sizeof(lo->file_path_length));
+	p += sizeof(lo->file_path_length);
+
+	memcpy(p, lo->label, label_len);
+	p += label_len;
+
+	memcpy(p, lo->file_path, lo->file_path_length);
+	p += lo->file_path_length;
+
+	if (lo->optional_data) {
+		utf8_utf16_strcpy((u16 **)&p, (const char *)lo->optional_data);
+		p += sizeof(u16); /* size of trailing \0 */
+	}
+	return size;
+}
+
+/**
+ * get_var() - get UEFI variable
+ *
+ * It is the caller's duty to free the returned buffer.
+ *
+ * @name:	name of variable
+ * @vendor:	vendor GUID of variable
+ * @size:	size of allocated buffer
+ * Return:	buffer with variable data or NULL
+ */
+static void *get_var(u16 *name, const efi_guid_t *vendor,
+		     efi_uintn_t *size)
+{
+	efi_guid_t *v = (efi_guid_t *)vendor;
+	efi_status_t ret;
+	void *buf = NULL;
+
+	*size = 0;
+	EFI_CALL(ret = rs->get_variable(name, v, NULL, size, buf));
+	if (ret == EFI_BUFFER_TOO_SMALL) {
+		buf = malloc(*size);
+		EFI_CALL(ret = rs->get_variable(name, v, NULL, size, buf));
+	}
+
+	if (ret != EFI_SUCCESS) {
+		free(buf);
+		*size = 0;
+		return NULL;
+	}
+
+	return buf;
+}
+
+/**
+ * try_load_entry() - try to load image for boot option
+ *
+ * Attempt to load load-option number 'n', returning device_path and file_path
+ * if successful. This checks that the EFI_LOAD_OPTION is active (enabled)
+ * and that the specified file to boot exists.
+ *
+ * @n:		number of the boot option, e.g. 0x0a13 for Boot0A13
+ * @handle:	on return handle for the newly installed image
+ * Return:	status code
+ */
+static efi_status_t try_load_entry(u16 n, efi_handle_t *handle)
+{
+	struct efi_load_option lo;
+	u16 varname[] = L"Boot0000";
+	u16 hexmap[] = L"0123456789ABCDEF";
+	void *load_option;
+	efi_uintn_t size;
+	efi_status_t ret;
+
+	varname[4] = hexmap[(n & 0xf000) >> 12];
+	varname[5] = hexmap[(n & 0x0f00) >> 8];
+	varname[6] = hexmap[(n & 0x00f0) >> 4];
+	varname[7] = hexmap[(n & 0x000f) >> 0];
+
+	load_option = get_var(varname, &efi_global_variable_guid, &size);
+	if (!load_option)
+		return EFI_LOAD_ERROR;
+
+	efi_deserialize_load_option(&lo, load_option);
+
+	if (lo.attributes & LOAD_OPTION_ACTIVE) {
+		u32 attributes;
+
+		debug("%s: trying to load \"%ls\" from %pD\n",
+		      __func__, lo.label, lo.file_path);
+
+		ret = EFI_CALL(efi_load_image(true, efi_root, lo.file_path,
+					      NULL, 0, handle));
+		if (ret != EFI_SUCCESS) {
+			printf("Loading from Boot%04X '%ls' failed\n", n,
+			       lo.label);
+			goto error;
+		}
+
+		attributes = EFI_VARIABLE_BOOTSERVICE_ACCESS |
+			     EFI_VARIABLE_RUNTIME_ACCESS;
+		size = sizeof(n);
+		ret = EFI_CALL(efi_set_variable(
+				L"BootCurrent",
+				(efi_guid_t *)&efi_global_variable_guid,
+				attributes, size, &n));
+		if (ret != EFI_SUCCESS) {
+			if (EFI_CALL(efi_unload_image(*handle))
+			    != EFI_SUCCESS)
+				printf("Unloading image failed\n");
+			goto error;
+		}
+
+		printf("Booting: %ls\n", lo.label);
+	} else {
+		ret = EFI_LOAD_ERROR;
+	}
+
+error:
+	free(load_option);
+
+	return ret;
+}
+
+/**
+ * efi_bootmgr_load() - try to load from BootNext or BootOrder
+ *
+ * Attempt to load from BootNext or in the order specified by BootOrder
+ * EFI variable, the available load-options, finding and returning
+ * the first one that can be loaded successfully.
+ *
+ * @handle:	on return handle for the newly installed image
+ * Return:	status code
+ */
+efi_status_t efi_bootmgr_load(efi_handle_t *handle)
+{
+	u16 bootnext, *bootorder;
+	efi_uintn_t size;
+	int i, num;
+	efi_status_t ret;
+
+	bs = systab.boottime;
+	rs = systab.runtime;
+
+	/* BootNext */
+	bootnext = 0;
+	size = sizeof(bootnext);
+	ret = EFI_CALL(efi_get_variable(L"BootNext",
+					(efi_guid_t *)&efi_global_variable_guid,
+					NULL, &size, &bootnext));
+	if (ret == EFI_SUCCESS || ret == EFI_BUFFER_TOO_SMALL) {
+		/* BootNext does exist here */
+		if (ret == EFI_BUFFER_TOO_SMALL || size != sizeof(u16))
+			printf("BootNext must be 16-bit integer\n");
+
+		/* delete BootNext */
+		ret = EFI_CALL(efi_set_variable(
+					L"BootNext",
+					(efi_guid_t *)&efi_global_variable_guid,
+					EFI_VARIABLE_NON_VOLATILE, 0,
+					&bootnext));
+
+		/* load BootNext */
+		if (ret == EFI_SUCCESS) {
+			if (size == sizeof(u16)) {
+				ret = try_load_entry(bootnext, handle);
+				if (ret == EFI_SUCCESS)
+					return ret;
+				printf("Loading from BootNext failed, falling back to BootOrder\n");
+			}
+		} else {
+			printf("Deleting BootNext failed\n");
+		}
+	}
+
+	/* BootOrder */
+	bootorder = get_var(L"BootOrder", &efi_global_variable_guid, &size);
+	if (!bootorder) {
+		printf("BootOrder not defined\n");
+		ret = EFI_NOT_FOUND;
+		goto error;
+	}
+
+	num = size / sizeof(uint16_t);
+	for (i = 0; i < num; i++) {
+		debug("%s: trying to load Boot%04X\n", __func__, bootorder[i]);
+		ret = try_load_entry(bootorder[i], handle);
+		if (ret == EFI_SUCCESS)
+			break;
+	}
+
+	free(bootorder);
+
+error:
+	return ret;
+}