util: add smmstoretool for editing SMMSTORE

Offline SMMSTORE variable modification tool.  Can be used to
pre-configure ROM image or debug EFI state stored in a dump.

Change-Id: I6c1c06f1d0c39c13b5be76a3070f09b715aca6e0
Signed-off-by: Sergii Dmytruk <sergii.dmytruk@3mdeb.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/79080
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Michał Żygowski <michal.zygowski@3mdeb.com>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>

util/smmstoretool/utils.h

@@ -0,0 +1,29 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#ifndef SMMSTORETOOL__UTILS_H__
+#define SMMSTORETOOL__UTILS_H__
+
+#include <stddef.h>
+#include <stdbool.h>
+#include <stdint.h>
+
+#include "udk2017.h"
+
+struct mem_range_t {
+	uint8_t *start;
+	size_t length;
+};
+
+void *xmalloc(size_t size);
+
+char *to_chars(const CHAR16 uchars[], size_t size);
+
+CHAR16 *to_uchars(const char chars[], size_t *size);
+
+bool str_eq(const char lhs[], const char rhs[]);
+
+struct mem_range_t map_file(const char path[], bool rw);
+
+void unmap_file(struct mem_range_t store);
+
+#endif // SMMSTORETOOL__UTILS_H__