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2025-05-04x86/boot/sev: Support memory acceptance in the EFI stub under SVSMArd Biesheuvel
Commit: d54d610243a4 ("x86/boot/sev: Avoid shared GHCB page for early memory acceptance") provided a fix for SEV-SNP memory acceptance from the EFI stub when running at VMPL #0. However, that fix was insufficient for SVSM SEV-SNP guests running at VMPL >0, as those rely on a SVSM calling area, which is a shared buffer whose address is programmed into a SEV-SNP MSR, and the SEV init code that sets up this calling area executes much later during the boot. Given that booting via the EFI stub at VMPL >0 implies that the firmware has configured this calling area already, reuse it for performing memory acceptance in the EFI stub. Fixes: fcd042e86422 ("x86/sev: Perform PVALIDATE using the SVSM when not at VMPL0") Tested-by: Tom Lendacky <thomas.lendacky@amd.com> Co-developed-by: Tom Lendacky <thomas.lendacky@amd.com> Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: <stable@vger.kernel.org> Cc: Dionna Amalie Glaze <dionnaglaze@google.com> Cc: Kevin Loughlin <kevinloughlin@google.com> Cc: linux-efi@vger.kernel.org Link: https://lore.kernel.org/r/20250428174322.2780170-2-ardb+git@google.com
2025-04-24x86/boot: Work around broken busybox 'truncate' toolArd Biesheuvel
The GNU coreutils version of truncate, which is the original, accepts a % prefix for the -s size argument which means the file in question should be padded to a multiple of the given size. This is currently used to pad the setup block of bzImage to a multiple of 4k before appending the decompressor. busybox reimplements truncate but does not support this idiom, and therefore fails the build since commit 9c54baab4401 ("x86/boot: Drop CRC-32 checksum and the build tool that generates it") Since very little build code within the kernel depends on the 'truncate' utility, work around this incompatibility by avoiding truncate altogether, and relying on dd to perform the padding. Fixes: 9c54baab4401 ("x86/boot: Drop CRC-32 checksum and the build tool that generates it") Reported-by: <phasta@kernel.org> Tested-by: Philipp Stanner <phasta@kernel.org> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lore.kernel.org/r/20250424101917.1552527-2-ardb+git@google.com
2025-04-18x86/boot/sev: Avoid shared GHCB page for early memory acceptanceArd Biesheuvel
Communicating with the hypervisor using the shared GHCB page requires clearing the C bit in the mapping of that page. When executing in the context of the EFI boot services, the page tables are owned by the firmware, and this manipulation is not possible. So switch to a different API for accepting memory in SEV-SNP guests, one which is actually supported at the point during boot where the EFI stub may need to accept memory, but the SEV-SNP init code has not executed yet. For simplicity, also switch the memory acceptance carried out by the decompressor when not booting via EFI - this only involves the allocation for the decompressed kernel, and is generally only called after kexec, as normal boot will jump straight into the kernel from the EFI stub. Fixes: 6c3211796326 ("x86/sev: Add SNP-specific unaccepted memory support") Tested-by: Tom Lendacky <thomas.lendacky@amd.com> Co-developed-by: Tom Lendacky <thomas.lendacky@amd.com> Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: <stable@vger.kernel.org> Cc: Dionna Amalie Glaze <dionnaglaze@google.com> Cc: Kevin Loughlin <kevinloughlin@google.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: linux-efi@vger.kernel.org Link: https://lore.kernel.org/r/20250404082921.2767593-8-ardb+git@google.com # discussion thread #1 Link: https://lore.kernel.org/r/20250410132850.3708703-2-ardb+git@google.com # discussion thread #2 Link: https://lore.kernel.org/r/20250417202120.1002102-2-ardb+git@google.com # final submission
2025-04-05Merge tag 'kbuild-v6.15' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull Kbuild updates from Masahiro Yamada: - Improve performance in gendwarfksyms - Remove deprecated EXTRA_*FLAGS and KBUILD_ENABLE_EXTRA_GCC_CHECKS - Support CONFIG_HEADERS_INSTALL for ARCH=um - Use more relative paths to sources files for better reproducibility - Support the loong64 Debian architecture - Add Kbuild bash completion - Introduce intermediate vmlinux.unstripped for architectures that need static relocations to be stripped from the final vmlinux - Fix versioning in Debian packages for -rc releases - Treat missing MODULE_DESCRIPTION() as an error - Convert Nios2 Makefiles to use the generic rule for built-in DTB - Add debuginfo support to the RPM package * tag 'kbuild-v6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (40 commits) kbuild: rpm-pkg: build a debuginfo RPM kconfig: merge_config: use an empty file as initfile nios2: migrate to the generic rule for built-in DTB rust: kbuild: skip `--remap-path-prefix` for `rustdoc` kbuild: pacman-pkg: hardcode module installation path kbuild: deb-pkg: don't set KBUILD_BUILD_VERSION unconditionally modpost: require a MODULE_DESCRIPTION() kbuild: make all file references relative to source root x86: drop unnecessary prefix map configuration kbuild: deb-pkg: add comment about future removal of KDEB_COMPRESS kbuild: Add a help message for "headers" kbuild: deb-pkg: remove "version" variable in mkdebian kbuild: deb-pkg: fix versioning for -rc releases Documentation/kbuild: Fix indentation in modules.rst example x86: Get rid of Makefile.postlink kbuild: Create intermediate vmlinux build with relocations preserved kbuild: Introduce Kconfig symbol for linking vmlinux with relocations kbuild: link-vmlinux.sh: Make output file name configurable kbuild: do not generate .tmp_vmlinux*.map when CONFIG_VMLINUX_MAP=y Revert "kheaders: Ignore silly-rename files" ...
2025-03-29Merge tag 'efi-next-for-v6.15' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi Pull EFI updates from Ard Biesheuvel: - Decouple mixed mode startup code from the traditional x86 decompressor - Revert zero-length file hack in efivarfs - Prevent EFI zboot from using the CopyMem/SetMem boot services after ExitBootServices() - Update EFI zboot to use the ZLIB/ZSTD library interfaces directly * tag 'efi-next-for-v6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi: efi/libstub: Avoid legacy decompressor zlib/zstd wrappers efi/libstub: Avoid CopyMem/SetMem EFI services after ExitBootServices efi: efibc: change kmalloc(size * count, ...) to kmalloc_array() efivarfs: Revert "allow creation of zero length files" x86/efi/mixed: Move mixed mode startup code into libstub x86/efi/mixed: Simplify and document thunking logic x86/efi/mixed: Remove dependency on legacy startup_32 code x86/efi/mixed: Set up 1:1 mapping of lower 4GiB in the stub x86/efi/mixed: Factor out and clean up long mode entry x86/efi/mixed: Check CPU compatibility without relying on verify_cpu() x86/efistub: Merge PE and handover entrypoints
2025-03-24x86 boot build: make git ignore stale 'tools' directoryLinus Torvalds
We've had this before: when we remove infrastructure to generate files, the old stale build artifacts still remain in-tree. And when the infrastructure to generate them is gone, so is the gitignore file for those build artifacts. End result: git will see the old generated files, and people will mistakenly commit them. That's what happened with the 'genheaders' file not that long ago (see commit 04a3389b3535 "Remove stale generated 'genheaders' file"). This time it's commit 9c54baab4401 ("x86/boot: Drop CRC-32 checksum and the build tool that generates it") that removed the 'build' file from the arch/x86/boot/tools/ subdirectory, and removed the .gitignore file too (because the whole subdirectory is gone). And as a result, if you don't do a 'git clean -dqfx' or similar to clean up your tree, 'git status' will say Untracked files: (use "git add <file>..." to include in what will be committed) arch/x86/boot/tools/ and some hapless sleep-deprived developer will inevitably decide that that means that they need to 'git add' that directory. Which would bring back some stale generated file that we most definitely do not want in the tree. So when removing directories that had special .gitignore patterns, make sure to add a new gitignore entry in the parent directory for the no longer existing subdirectory. It will avoid mistakes. Cc: Ard Biesheuvel <ardb@kernel.org> Cc: Ingo Molnar <mingo@kernel.org> Fixes: 9c54baab4401 ("x86/boot: Drop CRC-32 checksum and the build tool that generates it") Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2025-03-24Merge tag 'x86-boot-2025-03-22' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 boot code updates from Ingo Molnar: - Memblock setup and other early boot code cleanups (Mike Rapoport) - Export e820_table_kexec[] to sysfs (Dave Young) - Baby steps of adding relocate_kernel() debugging support (David Woodhouse) - Replace open-coded parity calculation with parity8() (Kuan-Wei Chiu) - Move the LA57 trampoline to separate source file (Ard Biesheuvel) - Misc micro-optimizations (Uros Bizjak) - Drop obsolete E820_TYPE_RESERVED_KERN and related code (Mike Rapoport) * tag 'x86-boot-2025-03-22' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/kexec: Add relocate_kernel() debugging support: Load a GDT x86/boot: Move the LA57 trampoline to separate source file x86/boot: Do not test if AC and ID eflags are changeable on x86_64 x86/bootflag: Replace open-coded parity calculation with parity8() x86/bootflag: Micro-optimize sbf_write() x86/boot: Add missing has_cpuflag() prototype x86/kexec: Export e820_table_kexec[] to sysfs x86/boot: Change some static bootflag functions to bool x86/e820: Drop obsolete E820_TYPE_RESERVED_KERN and related code x86/boot: Split parsing of boot_params into the parse_boot_params() helper function x86/boot: Split kernel resources setup into the setup_kernel_resources() helper function x86/boot: Move setting of memblock parameters to e820__memblock_setup()
2025-03-24Merge tag 'x86-build-2025-03-22' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 build updates from Ingo Molnar: - Drop CRC-32 checksum and the build tool that generates it (Ard Biesheuvel) - Fix broken copy command in genimage.sh when making isoimage (Nir Lichtman) * tag 'x86-build-2025-03-22' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/boot: Add back some padding for the CRC-32 checksum x86/boot: Drop CRC-32 checksum and the build tool that generates it x86/build: Fix broken copy command in genimage.sh when making isoimage
2025-03-22x86: drop unnecessary prefix map configurationThomas Weißschuh
The toplevel Makefile already provides -fmacro-prefix-map as part of KBUILD_CPPFLAGS. In contrast to the KBUILD_CFLAGS and KBUILD_AFLAGS variables, KBUILD_CPPFLAGS is not redefined in the architecture specific Makefiles. Therefore the toplevel KBUILD_CPPFLAGS do apply just fine, to both C and ASM sources. The custom configuration was necessary when it was added in commit 9e2276fa6eb3 ("arch/x86/boot: Use prefix map to avoid embedded paths") but has since become unnecessary in commit a716bd743210 ("kbuild: use -fmacro-prefix-map for .S sources"). Drop the now unnecessary custom prefix map configuration. Signed-off-by: Thomas Weißschuh <linux@weissschuh.net> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2025-03-19x86/headers: Replace __ASSEMBLY__ with __ASSEMBLER__ in non-UAPI headersThomas Huth
While the GCC and Clang compilers already define __ASSEMBLER__ automatically when compiling assembly code, __ASSEMBLY__ is a macro that only gets defined by the Makefiles in the kernel. This can be very confusing when switching between userspace and kernelspace coding, or when dealing with UAPI headers that rather should use __ASSEMBLER__ instead. So let's standardize on the __ASSEMBLER__ macro that is provided by the compilers now. This is mostly a mechanical patch (done with a simple "sed -i" statement), with some manual tweaks in <asm/frame.h>, <asm/hw_irq.h> and <asm/setup.h> that mentioned this macro in comments with some missing underscores. Signed-off-by: Thomas Huth <thuth@redhat.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Brian Gerst <brgerst@gmail.com> Cc: Juergen Gross <jgross@suse.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lore.kernel.org/r/20250314071013.1575167-38-thuth@redhat.com
2025-03-19x86/cpufeatures: Generate the <asm/cpufeaturemasks.h> header based on build ↵H. Peter Anvin (Intel)
config Introduce an AWK script to auto-generate the <asm/cpufeaturemasks.h> header with required and disabled feature masks based on <asm/cpufeatures.h> and the current build config. Thus for any CPU feature with a build config, e.g., X86_FRED, simply add: config X86_DISABLED_FEATURE_FRED def_bool y depends on !X86_FRED to arch/x86/Kconfig.cpufeatures, instead of adding a conditional CPU feature disable flag, e.g., DISABLE_FRED. Lastly, the generated required and disabled feature masks will be added to their corresponding feature masks for this particular compile-time configuration. [ Xin: build integration improvements ] [ mingo: Improved changelog and comments ] Signed-off-by: H. Peter Anvin (Intel) <hpa@zytor.com> Signed-off-by: Xin Li (Intel) <xin@zytor.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Nikolay Borisov <nik.borisov@suse.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lore.kernel.org/r/20250305184725.3341760-3-xin@zytor.com
2025-03-19Merge tag 'v6.14-rc7' into x86/core, to pick up fixesIngo Molnar
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2025-03-17x86: Get rid of Makefile.postlinkArd Biesheuvel
Instead of generating the vmlinux.relocs file (needed by the decompressor build to construct the KASLR relocation tables) as a vmlinux postlink step, which is dubious because it depends on data that is stripped from vmlinux before the build completes, generate it from vmlinux.unstripped, which has been introduced specifically for this purpose. This ensures that each artifact is rebuilt as needed, rather than as a side effect of another build rule. This effectively reverts commit 9d9173e9ceb6 ("x86/build: Avoid relocation information in final vmlinux") Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2025-03-13x86/boot: Move the LA57 trampoline to separate source fileArd Biesheuvel
To permit the EFI stub to call this code even when building the kernel without the legacy decompressor, move the trampoline out of the latter's startup code. This is part of an ongoing WIP effort on my part to make the existing, generic EFI zboot format work on x86 as well. No functional change intended. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20250313120324.1095968-2-ardb+git@google.com
2025-03-12x86/boot: Add back some padding for the CRC-32 checksumArd Biesheuvel
Even though no uses of the bzImage CRC-32 checksum are known, ensure that the last 4 bytes of the image are unused zero bytes, so that the checksum can be generated post-build if needed. [ mingo: Added the 'obsolete' qualifier to the comment. ] Suggested-by: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Ian Campbell <ijc@hellion.org.uk> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lore.kernel.org/r/20250312081204.521411-2-ardb+git@google.com
2025-03-08x86/boot: Do not test if AC and ID eflags are changeable on x86_64Uros Bizjak
The test for the changeabitily of AC and ID EFLAGS is used to distinguish between i386 and i486 processors (AC) and to test for CPUID instruction support (ID). Skip these tests on x86_64 processors as they always supports CPUID. Also change the return type of has_eflag() to bool. Signed-off-by: Uros Bizjak <ubizjak@gmail.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Brian Gerst <brgerst@gmail.com> Cc: Nathan Chancellor <nathan@kernel.org> Cc: Nick Desaulniers <ndesaulniers@google.com> Link: https://lore.kernel.org/r/20250307091022.181136-1-ubizjak@gmail.com
2025-03-07x86/boot: Drop CRC-32 checksum and the build tool that generates itArd Biesheuvel
Apart from some sanity checks on the size of setup.bin, the only remaining task carried out by the arch/x86/boot/tools/build.c build tool is generating the CRC-32 checksum of the bzImage. This feature was added in commit 7d6e737c8d2698b6 ("x86: add a crc32 checksum to the kernel image.") without any motivation (or any commit log text, for that matter). This checksum is not verified by any known bootloader, and given that a) the checksum of the entire bzImage is reported by most tools (zlib, rhash) as 0xffffffff and not 0x0 as documented, b) the checksum is corrupted when the image is signed for secure boot, which means that no distro ships x86 images with valid CRCs, it seems quite unlikely that this checksum is being used, so let's just drop it, along with the tool that generates it. Instead, use simple file concatenation and truncation to combine the two pieces into bzImage, and replace the checks on the size of the setup block with a couple of ASSERT()s in the linker script. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ian Campbell <ijc@hellion.org.uk> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lore.kernel.org/r/20250307164801.885261-2-ardb+git@google.com
2025-03-07Merge branch 'x86-mixed-mode' into efi/nextArd Biesheuvel
2025-03-06x86/boot: Sanitize boot params before parsing command lineArd Biesheuvel
The 5-level paging code parses the command line to look for the 'no5lvl' string, and does so very early, before sanitize_boot_params() has been called and has been given the opportunity to wipe bogus data from the fields in boot_params that are not covered by struct setup_header, and are therefore supposed to be initialized to zero by the bootloader. This triggers an early boot crash when using syslinux-efi to boot a recent kernel built with CONFIG_X86_5LEVEL=y and CONFIG_EFI_STUB=n, as the 0xff padding that now fills the unused PE/COFF header is copied into boot_params by the bootloader, and interpreted as the top half of the command line pointer. Fix this by sanitizing the boot_params before use. Note that there is no harm in calling this more than once; subsequent invocations are able to spot that the boot_params have already been cleaned up. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: <stable@vger.kernel.org> # v6.1+ Link: https://lore.kernel.org/r/20250306155915.342465-2-ardb+git@google.com Closes: https://lore.kernel.org/all/202503041549.35913.ulrich.gemkow@ikr.uni-stuttgart.de
2025-02-26x86/boot: Add missing has_cpuflag() prototypeZhou Ding
We get a warning when building the kernel with W=1: arch/x86/boot/compressed/cpuflags.c:4:6: warning: no previous prototype for ‘has_cpuflag’ [-Werror=missing-prototypes] 4 | bool has_cpuflag(int flag) | ^~~~~~~~~~~ Add a function declaration to cpuflags.h Signed-off-by: Zhou Ding <zhouding@cmss.chinamobile.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20241217162859.1167889-1-zhouding@cmss.chinamobile.com
2025-02-25x86/build: Fix broken copy command in genimage.sh when making isoimageNir Lichtman
Problem: Currently when running the "make isoimage" command there is an error related to wrong parameters passed to the cp command: "cp: missing destination file operand after 'arch/x86/boot/isoimage/'" This is caused because FDINITRDS is an empty array. Solution: Check if FDINITRDS is empty before executing the "cp" command, similar to how it is done in the case of hdimage. Signed-off-by: Nir Lichtman <nir@lichtman.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ard Biesheuvel <ardb@kernel.org> Cc: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Michal Marek <michal.lkml@markovi.net> Link: https://lore.kernel.org/r/20250110120500.GA923218@lichtman.org
2025-02-21x86/efi/mixed: Move mixed mode startup code into libstubArd Biesheuvel
The EFI mixed mode code has been decoupled from the legacy decompressor, in order to be able to reuse it with generic EFI zboot images for x86. Move the source file into the libstub source directory to facilitate this. Acked-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2025-02-21x86/efi/mixed: Simplify and document thunking logicArd Biesheuvel
Now that the GDT/IDT and data segment selector preserve/restore logic has been removed from the boot-time EFI mixed mode thunking routines, the remaining logic to handle the function arguments can be simplified: the setup of the arguments on the stack can be moved into the 32-bit callee, which is able to use a more idiomatic sequence of PUSH instructions. This, in turn, allows the far call and far return to be issued using plain LCALL and LRET instructions, removing the need to set up the return explicitly. Acked-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2025-02-21x86/efi/mixed: Remove dependency on legacy startup_32 codeArd Biesheuvel
The EFI mixed mode startup code calls into startup_32 in the legacy decompressor with a mocked up boot_params struct, only to get it to set up the 1:1 mapping of the lower 4 GiB of memory and switch to a GDT that supports 64-bit mode. In order to be able to reuse the EFI mixed mode startup code in EFI zboot images, which do not incorporate the legacy decompressor code, decouple it, by dealing with the GDT and IDT directly. Doing so makes it possible to construct a GDT that is compatible with the one the firmware uses, with one additional entry for a 64-bit mode code segment appended. This removes the need entirely to switch between GDTs and IDTs or data segment selector values and all of this code can be removed. Acked-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2025-02-21x86/efi/mixed: Set up 1:1 mapping of lower 4GiB in the stubArd Biesheuvel
In preparation for dropping the dependency on startup_32 entirely in the next patch, add the code that sets up the 1:1 mapping of the lower 4 GiB of system RAM to the mixed mode stub. The reload of CR3 after the long mode switch will be removed in a subsequent patch, when it is no longer needed. Acked-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2025-02-21x86/efi/mixed: Factor out and clean up long mode entryArd Biesheuvel
Entering long mode involves setting the EFER_LME and CR4.PAE bits before enabling paging by setting CR0.PG bit. It also involves disabling interrupts, given that the firmware's 32-bit IDT becomes invalid as soon as the CPU transitions into long mode. Reloading the CR3 register is not necessary at boot time, given that the EFI firmware as well as the kernel's EFI stub use a 1:1 mapping of the 32-bit addressable memory in the system. Break out this code into a separate helper for clarity, and so that it can be reused in a subsequent patch. Acked-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2025-02-21x86/efi/mixed: Check CPU compatibility without relying on verify_cpu()Ard Biesheuvel
In order for the EFI mixed mode startup code to be reusable in a context where the legacy decompressor is not used, replace the call to verify_cpu() [which performs an elaborate set of checks] with a simple check against the 'long mode' bit in the appropriate CPUID leaf. This is reasonable, given that EFI support is implied when booting in this manner, and so there is no need to consider very old CPUs when performing this check. Acked-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2025-02-21x86/efistub: Merge PE and handover entrypointsArd Biesheuvel
The difference between the PE and handover entrypoints in the EFI stub is that the former allocates a struct boot_params whereas the latter expects one from the caller. Currently, these are two completely separate entrypoints, duplicating some logic and both relying of efi_exit() to return straight back to the firmware on an error. Simplify this by making the PE entrypoint call the handover entrypoint with NULL as the argument for the struct boot_params parameter. This makes the code easier to follow, and removes the need to support two different calling conventions in the mixed mode asm code. While at it, move the assignment of boot_params_ptr into the function that actually calls into the legacy decompressor, which is where its value is required. Acked-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2025-02-18x86/boot/64: Remove inverse relocationsBrian Gerst
Inverse relocations were needed to offset the effects of relocation for RIP-relative accesses to zero-based percpu data. Now that the percpu section is linked normally as part of the kernel image, they are no longer needed. Signed-off-by: Brian Gerst <brgerst@gmail.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Ard Biesheuvel <ardb@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lore.kernel.org/r/20250123190747.745588-11-brgerst@gmail.com
2025-01-30x86/boot: Use '-std=gnu11' to fix build with GCC 15Nathan Chancellor
GCC 15 changed the default C standard version to C23, which should not have impacted the kernel because it requests the gnu11 standard via '-std=' in the main Makefile. However, the x86 compressed boot Makefile uses its own set of KBUILD_CFLAGS without a '-std=' value (i.e., using the default), resulting in errors from the kernel's definitions of bool, true, and false in stddef.h, which are reserved keywords under C23. ./include/linux/stddef.h:11:9: error: expected identifier before ‘false’ 11 | false = 0, ./include/linux/types.h:35:33: error: two or more data types in declaration specifiers 35 | typedef _Bool bool; Set '-std=gnu11' in the x86 compressed boot Makefile to resolve the error and consistently use the same C standard version for the entire kernel. Closes: https://lore.kernel.org/4OAhbllK7x4QJGpZjkYjtBYNLd_2whHx9oFiuZcGwtVR4hIzvduultkgfAIRZI3vQpZylu7Gl929HaYFRGeMEalWCpeMzCIIhLxxRhq4U-Y=@protonmail.com/ Closes: https://lore.kernel.org/Z4467umXR2PZ0M1H@tucnak/ Reported-by: Kostadin Shishmanov <kostadinshishmanov@protonmail.com> Reported-by: Jakub Jelinek <jakub@redhat.com> Signed-off-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Ard Biesheuvel <ardb@kernel.org> Cc:stable@vger.kernel.org Link: https://lore.kernel.org/all/20250121-x86-use-std-consistently-gcc-15-v1-1-8ab0acf645cb%40kernel.org
2025-01-21Merge tag 'x86-cleanups-2025-01-21' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 cleanups from Ingo Molnar: "Miscellaneous x86 cleanups and typo fixes, and also the removal of the 'disablelapic' boot parameter" * tag 'x86-cleanups-2025-01-21' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/ioapic: Remove a stray tab in the IO-APIC type string x86/cpufeatures: Remove "AMD" from the comments to the AMD-specific leaf Documentation/kernel-parameters: Fix a typo in kvm.enable_virt_at_load text x86/cpu: Fix typo in x86_match_cpu()'s doc x86/apic: Remove "disablelapic" cmdline option Documentation: Merge x86-specific boot options doc into kernel-parameters.txt x86/ioremap: Remove unused size parameter in remapping functions x86/ioremap: Simplify setup_data mapping variants x86/boot/compressed: Remove unused header includes from kaslr.c
2025-01-09x86/sev: Add the Secure TSC feature for SNP guestsNikunj A Dadhania
Now that all the required plumbing is done for enabling Secure TSC, add it to the SNP features present list. Signed-off-by: Nikunj A Dadhania <nikunj@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com> Tested-by: Peter Gonda <pgonda@google.com> Link: https://lore.kernel.org/r/20250106124633.1418972-14-nikunj@amd.com
2024-12-02x86/boot/compressed: Remove unused header includes from kaslr.cBorislav Petkov (AMD)
Nothing is using the linux/ namespace headers anymore. Remove them. Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://lore.kernel.org/r/20241130122644.GAZ0sEhD3Bm_9ZAIuc@fat_crate.local
2024-11-19Merge tag 'x86-cleanups-2024-11-18' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 cleanups from Ingo Molnar: - x86/boot: Remove unused function atou() (Dr. David Alan Gilbert) - x86/cpu: Use str_yes_no() helper in show_cpuinfo_misc() (Thorsten Blum) - x86/platform: Switch back to struct platform_driver::remove() (Uwe Kleine-König) * tag 'x86-cleanups-2024-11-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/boot: Remove unused function atou() x86/cpu: Use str_yes_no() helper in show_cpuinfo_misc() x86/platform: Switch back to struct platform_driver::remove()
2024-11-07x86/boot: Remove unused function atou()Dr. David Alan Gilbert
I can't find any sign of atou() having been used. Remove it. Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://lore.kernel.org/r/20240913005753.1392431-1-linux@treblig.org
2024-10-28x86/boot: Skip video memory access in the decompressor for SEV-ES/SNPAshish Kalra
Accessing guest video memory/RAM in the decompressor causes guest termination as the boot stage2 #VC handler for SEV-ES/SNP systems does not support MMIO handling. This issue is observed during a SEV-ES/SNP guest kexec as kexec -c adds screen_info to the boot parameters passed to the second kernel, which causes console output to be dumped to both video and serial. As the decompressor output gets cleared really fast, it is preferable to get the console output only on serial, hence, skip accessing the video RAM during decompressor stage to prevent guest termination. Serial console output during decompressor stage works as boot stage2 #VC handler already supports handling port I/O. [ bp: Massage. ] Suggested-by: Borislav Petkov (AMD) <bp@alien8.de> Suggested-by: Thomas Lendacky <thomas.lendacky@amd.com> Signed-off-by: Ashish Kalra <ashish.kalra@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com> Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com> Link: https://lore.kernel.org/r/8a55ea86524c686e575d273311acbe57ce8cee23.1722520012.git.ashish.kalra@amd.com
2024-09-01mm: rework accept memory helpersKirill A. Shutemov
Make accept_memory() and range_contains_unaccepted_memory() take 'start' and 'size' arguments instead of 'start' and 'end'. Remove accept_page(), replacing it with direct calls to accept_memory(). The accept_page() name is going to be used for a different function. Link: https://lkml.kernel.org/r/20240809114854.3745464-6-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Suggested-by: David Hildenbrand <david@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Mike Rapoport (Microsoft) <rppt@kernel.org> Cc: Tom Lendacky <thomas.lendacky@amd.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-23Merge tag 'kbuild-v6.11' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull Kbuild updates from Masahiro Yamada: - Remove tristate choice support from Kconfig - Stop using the PROVIDE() directive in the linker script - Reduce the number of links for the combination of CONFIG_KALLSYMS and CONFIG_DEBUG_INFO_BTF - Enable the warning for symbol reference to .exit.* sections by default - Fix warnings in RPM package builds - Improve scripts/make_fit.py to generate a FIT image with separate base DTB and overlays - Improve choice value calculation in Kconfig - Fix conditional prompt behavior in choice in Kconfig - Remove support for the uncommon EMAIL environment variable in Debian package builds - Remove support for the uncommon "name <email>" form for the DEBEMAIL environment variable - Raise the minimum supported GNU Make version to 4.0 - Remove stale code for the absolute kallsyms - Move header files commonly used for host programs to scripts/include/ - Introduce the pacman-pkg target to generate a pacman package used in Arch Linux - Clean up Kconfig * tag 'kbuild-v6.11' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (65 commits) kbuild: doc: gcc to CC change kallsyms: change sym_entry::percpu_absolute to bool type kallsyms: unify seq and start_pos fields of struct sym_entry kallsyms: add more original symbol type/name in comment lines kallsyms: use \t instead of a tab in printf() kallsyms: avoid repeated calculation of array size for markers kbuild: add script and target to generate pacman package modpost: use generic macros for hash table implementation kbuild: move some helper headers from scripts/kconfig/ to scripts/include/ Makefile: add comment to discourage tools/* addition for kernel builds kbuild: clean up scripts/remove-stale-files kconfig: recursive checks drop file/lineno kbuild: rpm-pkg: introduce a simple changelog section for kernel.spec kallsyms: get rid of code for absolute kallsyms kbuild: Create INSTALL_PATH directory if it does not exist kbuild: Abort make on install failures kconfig: remove 'e1' and 'e2' macros from expression deduplication kconfig: remove SYMBOL_CHOICEVAL flag kconfig: add const qualifiers to several function arguments kconfig: call expr_eliminate_yn() at least once in expr_eliminate_dups() ...
2024-07-20kbuild: Abort make on install failuresZhang Bingwu
Setting '-e' flag tells shells to exit with error exit code immediately after any of commands fails, and causes make(1) to regard recipes as failed. Before this, make will still continue to succeed even after the installation failed, for example, for insufficient permission or directory does not exist. Signed-off-by: Zhang Bingwu <xtexchooser@duck.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2024-07-16Merge tag 'efi-next-for-v6.11' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi Pull EFI updates from Ard Biesheuvel: "Note the removal of the EFI fake memory map support - this is believed to be unused and no longer worth supporting. However, we could easily bring it back if needed. With recent developments regarding confidential VMs and unaccepted memory, combined with kexec, creating a known inaccurate view of the firmware's memory map and handing it to the OS is a feature we can live without, hence the removal. Alternatively, I could imagine making this feature mutually exclusive with those confidential VM related features, but let's try simply removing it first. Summary: - Drop support for the 'fake' EFI memory map on x86 - Add an SMBIOS based tweak to the EFI stub instructing the firmware on x86 Macbook Pros to keep both GPUs enabled - Replace 0-sized array with flexible array in EFI memory attributes table handling - Drop redundant BSS clearing when booting via the native PE entrypoint on x86 - Avoid returning EFI_SUCCESS when aborting on an out-of-memory condition - Cosmetic tweak for arm64 KASLR loading logic" * tag 'efi-next-for-v6.11' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi: efi: Replace efi_memory_attributes_table_t 0-sized array with flexible array efi: Rename efi_early_memdesc_ptr() to efi_memdesc_ptr() arm64/efistub: Clean up KASLR logic x86/efistub: Drop redundant clearing of BSS x86/efistub: Avoid returning EFI_SUCCESS on error x86/efistub: Call Apple set_os protocol on dual GPU Intel Macs x86/efistub: Enable SMBIOS protocol handling for x86 efistub/smbios: Simplify SMBIOS enumeration API x86/efi: Drop support for fake EFI memory maps
2024-07-16Merge tag 'x86_sev_for_v6.11_rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 SEV updates from Borislav Petkov: - Add support for running the kernel in a SEV-SNP guest, over a Secure VM Service Module (SVSM). When running over a SVSM, different services can run at different protection levels, apart from the guest OS but still within the secure SNP environment. They can provide services to the guest, like a vTPM, for example. This series adds the required facilities to interface with such a SVSM module. - The usual fixlets, refactoring and cleanups [ And as always: "SEV" is AMD's "Secure Encrypted Virtualization". I can't be the only one who gets all the newer x86 TLA's confused, can I? - Linus ] * tag 'x86_sev_for_v6.11_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: Documentation/ABI/configfs-tsm: Fix an unexpected indentation silly x86/sev: Do RMP memory coverage check after max_pfn has been set x86/sev: Move SEV compilation units virt: sev-guest: Mark driver struct with __refdata to prevent section mismatch x86/sev: Allow non-VMPL0 execution when an SVSM is present x86/sev: Extend the config-fs attestation support for an SVSM x86/sev: Take advantage of configfs visibility support in TSM fs/configfs: Add a callback to determine attribute visibility sev-guest: configfs-tsm: Allow the privlevel_floor attribute to be updated virt: sev-guest: Choose the VMPCK key based on executing VMPL x86/sev: Provide guest VMPL level to userspace x86/sev: Provide SVSM discovery support x86/sev: Use the SVSM to create a vCPU when not in VMPL0 x86/sev: Perform PVALIDATE using the SVSM when not at VMPL0 x86/sev: Use kernel provided SVSM Calling Areas x86/sev: Check for the presence of an SVSM in the SNP secrets page x86/irqflags: Provide native versions of the local_irq_save()/restore()
2024-07-15Merge tag 'x86_cpu_for_v6.11_rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 cpu model updates from Borislav Petkov: - Flip the logic to add feature names to /proc/cpuinfo to having to explicitly specify the flag if there's a valid reason to show it in /proc/cpuinfo - Switch a bunch of Intel x86 model checking code to the new CPU model defines - Fixes and cleanups * tag 'x86_cpu_for_v6.11_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/cpu/intel: Drop stray FAM6 check with new Intel CPU model defines x86/cpufeatures: Flip the /proc/cpuinfo appearance logic x86/CPU/AMD: Always inline amd_clear_divider() x86/mce/inject: Add missing MODULE_DESCRIPTION() line perf/x86/rapl: Switch to new Intel CPU model defines x86/boot: Switch to new Intel CPU model defines x86/cpu: Switch to new Intel CPU model defines perf/x86/intel: Switch to new Intel CPU model defines x86/virt/tdx: Switch to new Intel CPU model defines x86/PCI: Switch to new Intel CPU model defines x86/cpu/intel: Switch to new Intel CPU model defines x86/platform/intel-mid: Switch to new Intel CPU model defines x86/pconfig: Remove unused MKTME pconfig code x86/cpu: Remove useless work in detect_tme_early()
2024-07-15Merge tag 'x86_cleanups_for_v6.11_rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 cleanups from Borislav Petkov: - Remove an unused function and the documentation of an already removed cmdline parameter * tag 'x86_cleanups_for_v6.11_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/boot: Remove unused function __fortify_panic() Documentation: Remove "mfgpt_irq=" from the kernel-parameters.txt file
2024-07-15Merge tag 'x86_boot_for_v6.11_rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 boot updates from Borislav Petkov: - Add a check to warn when cmdline parsing happens before the final cmdline string has been built and thus arguments can get lost - Code cleanups and simplifications * tag 'x86_boot_for_v6.11_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/setup: Warn when option parsing is done too early x86/boot: Clean up the arch/x86/boot/main.c code a bit x86/boot: Use current_stack_pointer to avoid asm() in init_heap()
2024-07-11x86/sev: Move SEV compilation unitsBorislav Petkov (AMD)
A long time ago it was agreed upon that the coco stuff needs to go where it belongs: https://lore.kernel.org/all/Yg5nh1RknPRwIrb8@zn.tnic and not keep it in arch/x86/kernel. TDX did that and SEV can't find time to do so. So lemme do it. If people have trouble converting their ongoing featuritis patches, ask me for a sed script. No functional changes. Move the instrumentation exclusion bits too, as helpfully caught and reported by the 0day folks. Closes: https://lore.kernel.org/oe-kbuild-all/202406220748.hG3qlmDx-lkp@intel.com Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-lkp/202407091342.46d7dbb-oliver.sang@intel.com Reported-by: kernel test robot <oliver.sang@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Nikunj A Dadhania <nikunj@amd.com> Reviewed-by: Ashish Kalra <ashish.kalra@amd.com> Tested-by: kernel test robot <oliver.sang@intel.com> Link: https://lore.kernel.org/r/20240619093014.17962-1-bp@kernel.org
2024-07-02x86/efi: Drop support for fake EFI memory mapsArd Biesheuvel
Between kexec and confidential VM support, handling the EFI memory maps correctly on x86 is already proving to be rather difficult (as opposed to other EFI architectures which manage to never modify the EFI memory map to begin with) EFI fake memory map support is essentially a development hack (for testing new support for the 'special purpose' and 'more reliable' EFI memory attributes) that leaked into production code. The regions marked in this manner are not actually recognized as such by the firmware itself or the EFI stub (and never have), and marking memory as 'more reliable' seems rather futile if the underlying memory is just ordinary RAM. Marking memory as 'special purpose' in this way is also dubious, but may be in use in production code nonetheless. However, the same should be achievable by using the memmap= command line option with the ! operator. EFI fake memmap support is not enabled by any of the major distros (Debian, Fedora, SUSE, Ubuntu) and does not exist on other architectures, so let's drop support for it. Acked-by: Borislav Petkov (AMD) <bp@alien8.de> Acked-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2024-06-17x86/sev: Allow non-VMPL0 execution when an SVSM is presentTom Lendacky
To allow execution at a level other than VMPL0, an SVSM must be present. Allow the SEV-SNP guest to continue booting if an SVSM is detected and the hypervisor supports the SVSM feature as indicated in the GHCB hypervisor features bitmap. [ bp: Massage a bit. ] Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://lore.kernel.org/r/2ce7cf281cce1d0cba88f3f576687ef75dc3c953.1717600736.git.thomas.lendacky@amd.com
2024-06-17x86/sev: Perform PVALIDATE using the SVSM when not at VMPL0Tom Lendacky
The PVALIDATE instruction can only be performed at VMPL0. If an SVSM is present, it will be running at VMPL0 while the guest itself is then running at VMPL1 or a lower privilege level. In that case, use the SVSM_CORE_PVALIDATE call to perform memory validation instead of issuing the PVALIDATE instruction directly. The validation of a single 4K page is now explicitly identified as such in the function name, pvalidate_4k_page(). The pvalidate_pages() function is used for validating 1 or more pages at either 4K or 2M in size. Each function, however, determines whether it can issue the PVALIDATE directly or whether the SVSM needs to be invoked. [ bp: Touchups. ] [ Tom: fold in a fix for Coconut SVSM: https://lore.kernel.org/r/234bb23c-d295-76e5-a690-7ea68dc1118b@amd.com ] Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://lore.kernel.org/r/4c4017d8b94512d565de9ccb555b1a9f8983c69c.1717600736.git.thomas.lendacky@amd.com
2024-06-14x86/boot: Remove unused function __fortify_panic()Nikolay Borisov
That function is only used when the kernel is compiled with FORTIFY_SOURCE and when the kernel proper string.h header is used. The decompressor code doesn't use the kernel proper header but has local copy which doesn't contain any fortified implementations of the various string functions. As such __fortify_panic() can never be called from the decompressor so remove it. Signed-off-by: Nikolay Borisov <nik.borisov@suse.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://lore.kernel.org/r/20240613110837.300273-1-nik.borisov@suse.com
2024-06-13x86/boot: Don't add the EFI stub to targets, againBenjamin Segall
This is a re-commit of da05b143a308 ("x86/boot: Don't add the EFI stub to targets") after the tagged patch incorrectly reverted it. vmlinux-objs-y is added to targets, with an assumption that they are all relative to $(obj); adding a $(objtree)/drivers/... path causes the build to incorrectly create a useless arch/x86/boot/compressed/drivers/... directory tree. Fix this just by using a different make variable for the EFI stub. Fixes: cb8bda8ad443 ("x86/boot/compressed: Rename efi_thunk_64.S to efi-mixed.S") Signed-off-by: Ben Segall <bsegall@google.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Ard Biesheuvel <ardb@kernel.org> Cc: stable@vger.kernel.org # v6.1+ Link: https://lore.kernel.org/r/xm267ceukksz.fsf@bsegall.svl.corp.google.com