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/udk2017.h

@@ -0,0 +1,30 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#ifndef SMMSTORETOOL__UDK2017_H__
+#define SMMSTORETOOL__UDK2017_H__
+
+#include <UDK2017/MdePkg/Include/Uefi/UefiBaseType.h>
+#include <UDK2017/MdePkg/Include/Uefi/UefiMultiPhase.h>
+#include <UDK2017/MdePkg/Include/Pi/PiFirmwareVolume.h>
+#include <UDK2017/MdeModulePkg/Include/Guid/VariableFormat.h>
+
+/*
+ * ProcessorBind.h contains `#pragma GCC visibility push(hidden)` guarded by an
+ * identical condition, but there is no corresponding `pop` pragma. This can
+ * cause trouble for code following headers above including libc headers because
+ * linker suddenly considers declarations from them (e.g., `strcmp()`) to be
+ * hidden.
+ *
+ * In order to address this situation all UDK2017 headers used by this tool
+ * must be listed above and included indirectly through this header which
+ * restores default visibility.
+ *
+ * Mind that this issue appears only if the following conditions are satisfied
+ * and not all toolchains are configured to build position-independent code by
+ * default (as if -fpic or -fpie appears on compilation command-line).
+ */
+#if defined(__GNUC__) && defined(__pic__) && !defined(USING_LTO)
+#pragma GCC visibility pop
+#endif
+
+#endif // SMMSTORETOOL__UDK2017_H__