kernel/linux.git/arch/x86/boot, branch v6.18.21

kbuild: Split .modinfo out from ELF_DETAILS

2026-03-12T11:09:44+00:00

commit 8678591b47469fe16357234efef9b260317b8be4 upstream. Commit 3e86e4d74c04 ("kbuild: keep .modinfo section in vmlinux.unstripped") added .modinfo to ELF_DETAILS while removing it from COMMON_DISCARDS, as it was needed in vmlinux.unstripped and ELF_DETAILS was present in all architecture specific vmlinux linker scripts. While this shuffle is fine for vmlinux, ELF_DETAILS and COMMON_DISCARDS may be used by other linker scripts, such as the s390 and x86 compressed boot images, which may not expect to have a .modinfo section. In certain circumstances, this could result in a bootloader failing to load the compressed kernel [1]. Commit ddc6cbef3ef1 ("s390/boot/vmlinux.lds.S: Ensure bzImage ends with SecureBoot trailer") recently addressed this for the s390 bzImage but the same bug remains for arm, parisc, and x86. The presence of .modinfo in the x86 bzImage was the root cause of the issue worked around with commit d50f21091358 ("kbuild: align modinfo section for Secureboot Authenticode EDK2 compat"). misc.c in arch/x86/boot/compressed includes lib/decompress_unzstd.c, which in turn includes lib/xxhash.c and its MODULE_LICENSE / MODULE_DESCRIPTION macros due to the STATIC definition. Split .modinfo out from ELF_DETAILS into its own macro and handle it in all vmlinux linker scripts. Discard .modinfo in the places where it was previously being discarded from being in COMMON_DISCARDS, as it has never been necessary in those uses. Cc: stable@vger.kernel.org Fixes: 3e86e4d74c04 ("kbuild: keep .modinfo section in vmlinux.unstripped") Reported-by: Ed W Closes: https://lore.kernel.org/587f25e0-a80e-46a5-9f01-87cb40cfa377@wildgooses.com/ [1] Tested-by: Ed W # x86_64 Link: https://patch.msgid.link/20260225-separate-modinfo-from-elf-details-v1-1-387ced6baf4b@kernel.org Signed-off-by: Nathan Chancellor Signed-off-by: Greg Kroah-Hartman

x86/boot/sev: Move SEV decompressor variables into the .data section

2026-03-12T11:09:37+00:00

commit 4ca191cec17a997d0e3b2cd312f3a884288acc27 upstream. As part of the work to remove the dependency on calling into the decompressor code (startup_64()) for a UEFI boot, a call to rmpadjust() was removed from sev_enable() in favor of checking the value of the snp_vmpl variable. When booting through a non-UEFI path and calling startup_64(), the call to sev_enable() is performed before the BSS section is zeroed. With the removal of the rmpadjust() call and the corresponding check of the return code, the snp_vmpl variable is checked. Since the kernel is running at VMPL0, the snp_vmpl variable will not have been set and should be the default value of 0. However, since the call occurs before the BSS is zeroed, the snp_vmpl variable may not actually be zero, which will cause the guest boot to fail. Since the decompressor relocates itself, the BSS would need to be cleared both before and after the relocation, but this would, in effect, cause all of the changes to BSS variables before relocation to be lost after relocation. Instead, move the snp_vmpl variable into the .data section so that it is initialized and the value made safe during relocation. As a pre-caution against future changes, move other SEV-related decompressor variables into the .data section, too. Fixes: 68a501d7fd82 ("x86/boot: Drop redundant RMPADJUST in SEV SVSM presence check") Signed-off-by: Tom Lendacky Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Ard Biesheuvel Reviewed-by: Changyuan Lyu Tested-by: Kevin Hui Tested-by: Changyuan Lyu Cc: stable@vger.kernel.org Link: https://patch.msgid.link/5648b7de5b0a5d0dfef3785f9582b718678c6448.1770217260.git.thomas.lendacky@amd.com Signed-off-by: Greg Kroah-Hartman

x86/sev: Allow IBPB-on-Entry feature for SNP guests

2026-03-12T11:09:37+00:00

commit 9073428bb204d921ae15326bb7d4558d9d269aab upstream. The SEV-SNP IBPB-on-Entry feature does not require a guest-side implementation. It was added in Zen5 h/w, after the first SNP Zen implementation, and thus was not accounted for when the initial set of SNP features were added to the kernel. In its abundant precaution, commit 8c29f0165405 ("x86/sev: Add SEV-SNP guest feature negotiation support") included SEV_STATUS' IBPB-on-Entry bit as a reserved bit, thereby masking guests from using the feature. Allow guests to make use of IBPB-on-Entry when supported by the hypervisor, as the bit is now architecturally defined and safe to expose. Fixes: 8c29f0165405 ("x86/sev: Add SEV-SNP guest feature negotiation support") Signed-off-by: Kim Phillips Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Nikunj A Dadhania Reviewed-by: Tom Lendacky Cc: stable@kernel.org Link: https://patch.msgid.link/20260203222405.4065706-2-kim.phillips@amd.com Signed-off-by: Greg Kroah-Hartman

x86/boot: Handle relative CONFIG_EFI_SBAT_FILE file paths

2026-03-12T11:09:37+00:00

commit 3d1973a0c76a78a4728cff13648a188ed486cf44 upstream. CONFIG_EFI_SBAT_FILE can be a relative path. When compiling using a different output directory (O=) the build currently fails because it can't find the filename set in CONFIG_EFI_SBAT_FILE: arch/x86/boot/compressed/sbat.S: Assembler messages: arch/x86/boot/compressed/sbat.S:6: Error: file not found: kernel.sbat Add $(srctree) as include dir for sbat.o. [ bp: Massage commit message. ] Fixes: 61b57d35396a ("x86/efi: Implement support for embedding SBAT data for x86") Signed-off-by: Jan Stancek Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Vitaly Kuznetsov Cc: Link: https://patch.msgid.link/f4eda155b0cef91d4d316b4e92f5771cb0aa7187.1772047658.git.jstancek@redhat.com Signed-off-by: Greg Kroah-Hartman

x86/boot: Fix page table access in 5-level to 4-level paging transition

2025-12-18T13:02:51+00:00

[ Upstream commit eb2266312507d7b757859e2227aa5c4ba6280ebe ] When transitioning from 5-level to 4-level paging, the existing code incorrectly accesses page table entries by directly dereferencing CR3 and applying PAGE_MASK. This approach has several issues: - __native_read_cr3() returns the raw CR3 register value, which on x86_64 includes not just the physical address but also flags. Bits above the physical address width of the system i.e. above __PHYSICAL_MASK_SHIFT) are also not masked. - The PGD entry is masked by PAGE_SIZE which doesn't take into account the higher bits such as _PAGE_BIT_NOPTISHADOW. Replace this with proper accessor functions: - native_read_cr3_pa(): Uses CR3_ADDR_MASK to additionally mask metadata out of CR3 (like SME or LAM bits). All remaining bits are real address bits or reserved and must be 0. - mask pgd value with PTE_PFN_MASK instead of PAGE_MASK, accounting for flags above bit 51 (_PAGE_BIT_NOPTISHADOW in particular). Bits below 51, but above the max physical address are reserved and must be 0. Fixes: e9d0e6330eb8 ("x86/boot/compressed/64: Prepare new top-level page table for trampoline") Reported-by: Michael van der Westhuizen Reported-by: Tobias Fleig Co-developed-by: Kiryl Shutsemau Signed-off-by: Kiryl Shutsemau Signed-off-by: Usama Arif Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Ard Biesheuvel Acked-by: Dave Hansen Link: https://lore.kernel.org/r/a482fd68-ce54-472d-8df1-33d6ac9f6bb5@intel.com Signed-off-by: Sasha Levin

Merge tag 'x86_cleanups_for_v6.18_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2025-10-11T17:51:14+00:00

Pull x86 cleanups from Borislav Petkov: - Simplify inline asm flag output operands now that the minimum compiler version supports the =@ccCOND syntax - Remove a bunch of AS_* Kconfig symbols which detect assembler support for various instruction mnemonics now that the minimum assembler version supports them all - The usual cleanups all over the place * tag 'x86_cleanups_for_v6.18_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/asm: Remove code depending on __GCC_ASM_FLAG_OUTPUTS__ x86/sgx: Use ENCLS mnemonic in x86/mtrr: Remove license boilerplate text with bad FSF address x86/asm: Use RDPKRU and WRPKRU mnemonics in x86/idle: Use MONITORX and MWAITX mnemonics in x86/entry/fred: Push __KERNEL_CS directly x86/kconfig: Remove CONFIG_AS_AVX512 crypto: x86 - Remove CONFIG_AS_VPCLMULQDQ crypto: X86 - Remove CONFIG_AS_VAES crypto: x86 - Remove CONFIG_AS_GFNI x86/kconfig: Drop unused and needless config X86_64_SMP

x86/boot: Drop erroneous __init annotation from early_set_pages_state()

2025-09-24T16:08:34+00:00

The kexec code will call set_pages_state() after tearing down all the GHCBs, which will therefore result in a call to early_set_pages_state(). This means the __init annotation is wrong, and must be dropped. Fixes: c5c30a373693 ("x86/boot: Move startup code out of __head section") Reported-by: Srikanth Aithal Signed-off-by: Ard Biesheuvel Signed-off-by: Borislav Petkov (AMD) Tested-by: Srikanth Aithal

x86/startup/sev: Document the CPUID flow in the boot #VC handler

2025-09-10T15:23:24+00:00

Document the CPUID reading the different SEV guest types do - the SNP one which relies on the presence of a CPUID table and the SEV-ES one, which reads the CPUID supplied by the hypervisor. The intent being to clarify the two back-to-back, similar CPUID invocations. No functional changes. [ bp: Turn into a proper patch. ] Signed-off-by: Tom Lendacky Signed-off-by: Borislav Petkov (AMD) Link: https://lore.kernel.org/r/fbb24767-0e06-d1d6-36e0-1757d98aca66@amd.com

x86/asm: Remove code depending on __GCC_ASM_FLAG_OUTPUTS__

2025-09-08T13:38:06+00:00

The minimum supported GCC version is 8.1, which supports flag output operands and always defines __GCC_ASM_FLAG_OUTPUTS__ macro. Remove code depending on __GCC_ASM_FLAG_OUTPUTS__ and use the "=@ccCOND" flag output operand directly. Use the equivalent "=@ccz" instead of "=@cce" flag output operand for CMPXCHG8B and CMPXCHG16B instructions. These instructions set a single flag bit - the Zero flag - and "=@ccz" is used to distinguish the CC user from comparison instructions, where set ZERO flag indeed means that the values are equal. Signed-off-by: Uros Bizjak Signed-off-by: Borislav Petkov (AMD) Link: https://lore.kernel.org/r/20250905121723.GCaLrU04lP2A50PT-B@fat_crate.local

Merge branch 'x86/apic' into x86/sev, to resolve conflict

2025-09-05T07:01:42+00:00

Conflicts: arch/x86/include/asm/sev-internal.h Signed-off-by: Ingo Molnar