kernel/arch/x86/boot/header.S, branch linux-rolling-stable

x86/efi: Implement support for embedding SBAT data for x86

2025-06-21T11:53:44Z

Similar to zboot architectures, implement support for embedding SBAT data for x86. Put '.sbat' section in between '.data' and '.text' as the former also covers '.bss' and '.pgtable' and thus must be the last one in the file. Signed-off-by: Vitaly Kuznetsov Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Ard Biesheuvel Link: https://lore.kernel.org/20250603091951.57775-1-vkuznets@redhat.com

Merge tag 'efi-next-for-v6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi

2025-05-30T19:42:57Z

Pull EFI updates from Ard Biesheuvel: "Not a lot going on in the EFI tree this cycle. The only thing that stands out is the new support for SBAT metadata, which was a bit contentious when it was first proposed, because in the initial incarnation, it would have required us to maintain a revocation index, and bump it each time a vulnerability affecting UEFI secure boot got fixed. This was shot down for obvious reasons. This time, only the changes needed to emit the SBAT section into the PE/COFF image are being carried upstream, and it is up to the distros to decide what to put in there when creating and signing the build. This only has the EFI zboot bits (which the distros will be using for arm64); the x86 bzImage changes should be arriving next cycle, presumably via the -tip tree. Summary: - Add support for emitting a .sbat section into the EFI zboot image, so that downstreams can easily include revocation metadata in the signed EFI images - Align PE symbolic constant names with other projects - Bug fix for the efi_test module - Log the physical address and size of the EFI memory map when failing to map it - A kerneldoc fix for the EFI stub code" * tag 'efi-next-for-v6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi: include: pe.h: Fix PE definitions efi/efi_test: Fix missing pending status update in getwakeuptime efi: zboot specific mechanism for embedding SBAT section efi/libstub: Describe missing 'out' parameter in efi_load_initrd efi: Improve logging around memmap init

include: pe.h: Fix PE definitions

2025-05-21T14:46:37Z

* Rename constants to their standard PE names: - MZ_MAGIC -> IMAGE_DOS_SIGNATURE - PE_MAGIC -> IMAGE_NT_SIGNATURE - PE_OPT_MAGIC_PE32_ROM -> IMAGE_ROM_OPTIONAL_HDR_MAGIC - PE_OPT_MAGIC_PE32 -> IMAGE_NT_OPTIONAL_HDR32_MAGIC - PE_OPT_MAGIC_PE32PLUS -> IMAGE_NT_OPTIONAL_HDR64_MAGIC - IMAGE_DLL_CHARACTERISTICS_NX_COMPAT -> IMAGE_DLLCHARACTERISTICS_NX_COMPAT * Import constants and their description from readpe and file projects which contains current up-to-date information: - IMAGE_FILE_MACHINE_* - IMAGE_FILE_* - IMAGE_SUBSYSTEM_* - IMAGE_DLLCHARACTERISTICS_* - IMAGE_DLLCHARACTERISTICS_EX_* - IMAGE_DEBUG_TYPE_* * Add missing IMAGE_SCN_* constants and update their incorrect description * Fix incorrect value of IMAGE_SCN_MEM_PURGEABLE constant * Add description for win32_version and loader_flags PE fields Signed-off-by: Pali Rohár Signed-off-by: Ard Biesheuvel

x86/mm/64: Make 5-level paging support unconditional

2025-05-17T08:38:16Z

Both Intel and AMD CPUs support 5-level paging, which is expected to become more widely adopted in the future. All major x86 Linux distributions have the feature enabled. Remove CONFIG_X86_5LEVEL and related #ifdeffery for it to make it more readable. Suggested-by: Borislav Petkov Signed-off-by: Kirill A. Shutemov Signed-off-by: Ingo Molnar Reviewed-by: Ard Biesheuvel Reviewed-by: Borislav Petkov (AMD) Cc: Dave Hansen Cc: H. Peter Anvin Cc: Linus Torvalds Link: https://lore.kernel.org/r/20250516123306.3812286-4-kirill.shutemov@linux.intel.com

x86/boot: Remove semicolon from "rep" prefixes

2025-04-18T07:32:57Z

Minimum version of binutils required to compile the kernel is 2.25. This version correctly handles the "rep" prefixes, so it is possible to remove the semicolon, which was used to support ancient versions of GNU as. Due to the semicolon, the compiler considers "rep; insn" (or its alternate "rep\n\tinsn" form) as two separate instructions. Removing the semicolon makes asm length calculations more accurate, consequently making scheduling and inlining decisions of the compiler more accurate. Removing the semicolon also enables assembler checks involving "rep" prefixes. Trying to assemble e.g. "rep addl %eax, %ebx" results in: Error: invalid instruction `add' after `rep' Signed-off-by: Uros Bizjak Signed-off-by: Ingo Molnar Cc: Andy Lutomirski Cc: Brian Gerst Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Juergen Gross Cc: Kees Cook Cc: Linus Torvalds Cc: Martin Mares Cc: Peter Zijlstra Link: https://lore.kernel.org/r/20250418071437.4144391-1-ubizjak@gmail.com

efi/x86: Set the PE/COFF header's NX compat flag unconditionally

2024-02-28T13:23:55Z

Now that the proper section and file alignment is used, and the EFI memory attributes protocol to manage executable permissions where needed is invoked, set the NX compat flag unconditionally. [ bp: Remove the "we"s. ] Signed-off-by: Ard Biesheuvel Signed-off-by: Borislav Petkov (AMD) Link: https://lore.kernel.org/r/20240116085347.2193966-2-ardb+git@google.com

x86/efistub: Use 1:1 file:memory mapping for PE/COFF .compat section

2024-02-05T10:24:51Z

The .compat section is a dummy PE section that contains the address of the 32-bit entrypoint of the 64-bit kernel image if it is bootable from 32-bit firmware (i.e., CONFIG_EFI_MIXED=y) This section is only 8 bytes in size and is only referenced from the loader, and so it is placed at the end of the memory view of the image, to avoid the need for padding it to 4k, which is required for sections appearing in the middle of the image. Unfortunately, this violates the PE/COFF spec, and even if most EFI loaders will work correctly (including the Tianocore reference implementation), PE loaders do exist that reject such images, on the basis that both the file and memory views of the file contents should be described by the section headers in a monotonically increasing manner without leaving any gaps. So reorganize the sections to avoid this issue. This results in a slight padding overhead (< 4k) which can be avoided if desired by disabling CONFIG_EFI_MIXED (which is only needed in rare cases these days) Fixes: 3e3eabe26dc8 ("x86/boot: Increase section and file alignment to 4k/512") Reported-by: Mike Beaton Link: https://lkml.kernel.org/r/CAHzAAWQ6srV6LVNdmfbJhOwhBw5ZzxxZZ07aHt9oKkfYAdvuQQ%40mail.gmail.com Signed-off-by: Ard Biesheuvel

x86/boot: Increase section and file alignment to 4k/512

2023-09-17T17:48:44Z

Align x86 with other EFI architectures, and increase the section alignment to the EFI page size (4k), so that firmware is able to honour the section permission attributes and map code read-only and data non-executable. There are a number of requirements that have to be taken into account: - the sign tools get cranky when there are gaps between sections in the file view of the image - the virtual offset of each section must be aligned to the image's section alignment - the file offset *and size* of each section must be aligned to the image's file alignment - the image size must be aligned to the section alignment - each section's virtual offset must be greater than or equal to the size of the headers. In order to meet all these requirements, while avoiding the need for lots of padding to accommodate the .compat section, the latter is placed at an arbitrary offset towards the end of the image, but aligned to the minimum file alignment (512 bytes). The space before the .text section is therefore distributed between the PE header, the .setup section and the .compat section, leaving no gaps in the file coverage, making the signing tools happy. Signed-off-by: Ard Biesheuvel Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/20230915171623.655440-18-ardb@google.com

x86/boot: Split off PE/COFF .data section

2023-09-17T17:48:43Z

Describe the code and data of the decompressor binary using separate .text and .data PE/COFF sections, so that we will be able to map them using restricted permissions once we increase the section and file alignment sufficiently. This avoids the need for memory mappings that are writable and executable at the same time, which is something that is best avoided for security reasons. Signed-off-by: Ard Biesheuvel Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/20230915171623.655440-17-ardb@google.com

x86/boot: Drop PE/COFF .reloc section

2023-09-17T17:48:43Z

Ancient buggy EFI loaders may have required a .reloc section to be present at some point in time, but this has not been true for a long time so the .reloc section can just be dropped. Signed-off-by: Ard Biesheuvel Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/20230915171623.655440-16-ardb@google.com