AppleEfiBootRtInfo: Initial import

macOS 13 Developer Beta 1 introduced a new driver, bootrt.efi, which
now carries the kernel call gate. It communicates with efiboot via an
info buffer passed via LoadOptions.

Include/Apple/IndustryStandard/AppleEfiBootRtInfo.h

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+/** @file
+  Copyright (C) 2022, Marvin Häuser. All rights reserved.
+
+  This program and the accompanying materials
+  are licensed and made available under the terms and conditions of the BSD License
+  which accompanies this distribution.  The full text of the license may be found at
+  http://opensource.org/licenses/bsd-license.php
+
+  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+**/
+
+#ifndef APPLE_EFI_BOOT_RT_INFO_H
+#define APPLE_EFI_BOOT_RT_INFO_H
+
+///
+/// The state value for when EfiBootRt has not been launched.
+///
+#define APPLE_EFI_BOOT_RT_STATE_NONE  SIGNATURE_32 ('b', 'r', '\0', '\0')
+
+///
+/// The state value for when EfiBootRt has been launched.
+///
+#define APPLE_EFI_BOOT_RT_STATE_LAUNCHED  SIGNATURE_32 ('b', 'r', 'H', 'i')
+
+///
+/// Arguments to the actual kernel call gate.
+///
+typedef struct {
+  ///
+  /// The address of the kernel entry point.
+  ///
+  UINTN    EntryPoint;
+  ///
+  /// The kernel argument handle.
+  ///
+  UINTN    Args;
+} APPLE_EFI_BOOT_RT_KCG_ARGS;
+
+/*
+  The kernel call gate transfers control to the Apple XNU kernel.
+
+  @param[in]  SystemTable   A pointer to the EFI System Table.
+  @param[in]  KcgArguments  Arguments to the kernel call gate.
+
+  @retval EFI_ABORTED  The kernel could not be started.
+  @retval other        On success, this function does not return.
+*/
+typedef
+EFI_STATUS
+(EFIAPI *APPLE_EFI_BOOT_RT_KCG)(
+  IN EFI_SYSTEM_TABLE                  *SystemTable,
+  IN CONST APPLE_EFI_BOOT_RT_KCG_ARGS  *KcgArguments
+  );
+
+///
+/// Apple EfiBootRt communication structure.
+///
+typedef struct {
+  ///
+  /// The image buffer of EfiBootRt.
+  ///
+  VOID                     *ImageBase;
+  ///
+  /// The size, in pages, of ImageBase.
+  ///
+  UINT64                   ImageNumPages;
+  ///
+  /// The current state of EfiBootRt.
+  ///
+  CONST UINT32             *State;
+  ///
+  /// The kernel call gate function.
+  ///
+  APPLE_EFI_BOOT_RT_KCG    KernelCallGate;
+  ///
+  /// The EfiBootRt build info string.
+  ///
+  CONST CHAR8              *BuildInfo;
+  ///
+  /// The EfiBootRt version string.
+  ///
+  CONST CHAR8              *VersionStr;
+} APPLE_EFI_BOOT_RT_INFO;
+
+#endif // APPLE_EFI_BOOT_RT_INFO_H