x86/setup: Move internal setup_data structures into setup_data.h

Move struct_efi_setup_data in order to unify duplicated definition of
the data structure in a single place. Also silence clang's warnings
about GNU extensions in real-mode code which might occur from the
changed includes.

[ bp: Massage commit message. ]

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20240112095000.8952-3-tzimmermann@suse.de

x86/boot/compressed: Handle unaccepted memory

The firmware will pre-accept the memory used to run the stub. But, the
stub is responsible for accepting the memory into which it decompresses
the main kernel. Accept memory just before decompression starts.

The stub is also responsible for choosing a physical address in which to
place the decompressed kernel image. The KASLR mechanism will randomize
this physical address. Since the accepted memory region is relatively
small, KASLR would be quite ineffective if it only used the pre-accepted
area (EFI_CONVENTIONAL_MEMORY). Ensure that KASLR randomizes among the
entire physical address space by also including EFI_UNACCEPTED_MEMORY.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Liam Merwick <liam.merwick@oracle.com>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lore.kernel.org/r/20230606142637.5171-5-kirill.shutemov@linux.intel.com

x86/boot: Add an efi.h header for the decompressor

Copy the needed symbols only and remove the kernel proper includes.

No functional changes.

Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/YlCKWhMJEMUgJmjF@zn.tnic