kernel/linux.git/arch/x86/include/asm, branch v5.15.209

Revert "x86/vdso: Fix output operand size of RDPID"

2026-06-01T15:35:45+00:00

This reverts commit 64f14b1ab6f39a704b62bf9b3fa28803cf2b3ebe. Signed-off-by: Sasha Levin

x86/CPU/AMD: Prevent improper isolation of shared resources in Zen2's op cache

2026-05-15T12:48:45+00:00

commit c21b90f77687075115d989e53a8ec5e2bb427ab1 upstream. Make sure resources are not improperly shared in the op cache and cause instruction corruption this way. Signed-off-by: Prathyushi Nangia Co-developed-by: Borislav Petkov (AMD) Signed-off-by: Borislav Petkov (AMD) Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman

x86/CPU/AMD: Add X86_FEATURE_ZEN1

2026-05-15T12:48:45+00:00

Commit 232afb557835d6f6859c73bf610bad308c96b131 upstream. Add a synthetic feature flag specifically for first generation Zen machines. There's need to have a generic flag for all Zen generations so make X86_FEATURE_ZEN be that flag. Fixes: 30fa92832f40 ("x86/CPU/AMD: Add ZenX generations flags") Suggested-by: Brian Gerst Suggested-by: Tom Lendacky Signed-off-by: Borislav Petkov (AMD) Link: https://lore.kernel.org/r/dc3835e3-0731-4230-bbb9-336bbe3d042b@amd.com Signed-off-by: Greg Kroah-Hartman

x86/CPU/AMD: Add ZenX generations flags

2026-05-15T12:48:45+00:00

Commit 30fa92832f405d5ac9f263e99f62445fa3084008 upstream. Add X86_FEATURE flags for each Zen generation. They should be used from now on instead of checking f/m/s. Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Nikolay Borisov Acked-by: Thomas Gleixner Link: http://lore.kernel.org/r/20231120104152.13740-2-bp@alien8.de Signed-off-by: Greg Kroah-Hartman

x86/CPU: Fix FPDSS on Zen1

2026-04-18T08:33:11+00:00

commit e55d98e7756135f32150b9b8f75d580d0d4b2dd3 upstream. Zen1's hardware divider can leave, under certain circumstances, partial results from previous operations. Those results can be leaked by another, attacker thread. Fix that with a chicken bit. Signed-off-by: Borislav Petkov (AMD) Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

x86/efi: defer freeing of boot services memory

2026-04-18T08:33:08+00:00

commit a4b0bf6a40f3c107c67a24fbc614510ef5719980 upstream. efi_free_boot_services() frees memory occupied by EFI_BOOT_SERVICES_CODE and EFI_BOOT_SERVICES_DATA using memblock_free_late(). There are two issue with that: memblock_free_late() should be used for memory allocated with memblock_alloc() while the memory reserved with memblock_reserve() should be freed with free_reserved_area(). More acutely, with CONFIG_DEFERRED_STRUCT_PAGE_INIT=y efi_free_boot_services() is called before deferred initialization of the memory map is complete. Benjamin Herrenschmidt reports that this causes a leak of ~140MB of RAM on EC2 t3a.nano instances which only have 512MB or RAM. If the freed memory resides in the areas that memory map for them is still uninitialized, they won't be actually freed because memblock_free_late() calls memblock_free_pages() and the latter skips uninitialized pages. Using free_reserved_area() at this point is also problematic because __free_page() accesses the buddy of the freed page and that again might end up in uninitialized part of the memory map. Delaying the entire efi_free_boot_services() could be problematic because in addition to freeing boot services memory it updates efi.memmap without any synchronization and that's undesirable late in boot when there is concurrency. More robust approach is to only defer freeing of the EFI boot services memory. Split efi_free_boot_services() in two. First efi_unmap_boot_services() collects ranges that should be freed into an array then efi_free_boot_services() later frees them after deferred init is complete. Link: https://lore.kernel.org/all/ec2aaef14783869b3be6e3c253b2dcbf67dbc12a.camel@kernel.crashing.org Fixes: 916f676f8dc0 ("x86, efi: Retain boot service code until after switching to virtual mode") Cc: Signed-off-by: Mike Rapoport (Microsoft) Reviewed-by: Benjamin Herrenschmidt Signed-off-by: Ard Biesheuvel Signed-off-by: Greg Kroah-Hartman

x86/kfence: fix booting on 32bit non-PAE systems

2026-02-11T12:35:26+00:00

commit 16459fe7e0ca6520a6e8f603de4ccd52b90fd765 upstream. The original patch inverted the PTE unconditionally to avoid L1TF-vulnerable PTEs, but Linux doesn't make this adjustment in 2-level paging. Adjust the logic to use the flip_protnone_guard() helper, which is a nop on 2-level paging but inverts the address bits in all other paging modes. This doesn't matter for the Xen aspect of the original change. Linux no longer supports running 32bit PV under Xen, and Xen doesn't support running any 32bit PV guests without using PAE paging. Link: https://lkml.kernel.org/r/20260126211046.2096622-1-andrew.cooper3@citrix.com Fixes: b505f1944535 ("x86/kfence: avoid writing L1TF-vulnerable PTEs") Reported-by: Ryusuke Konishi Closes: https://lore.kernel.org/lkml/CAKFNMokwjw68ubYQM9WkzOuH51wLznHpEOMSqtMoV1Rn9JV_gw@mail.gmail.com/ Signed-off-by: Andrew Cooper Tested-by: Ryusuke Konishi Tested-by: Borislav Petkov (AMD) Cc: Alexander Potapenko Cc: Marco Elver Cc: Dmitry Vyukov Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Dave Hansen Cc: "H. Peter Anvin" Cc: Jann Horn Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman

x86/kfence: avoid writing L1TF-vulnerable PTEs

2026-02-06T15:41:54+00:00

commit b505f1944535f83d369ae68813e7634d11b990d3 upstream. For native, the choice of PTE is fine. There's real memory backing the non-present PTE. However, for XenPV, Xen complains: (XEN) d1 L1TF-vulnerable L1e 8010000018200066 - Shadowing To explain, some background on XenPV pagetables: Xen PV guests are control their own pagetables; they choose the new PTE value, and use hypercalls to make changes so Xen can audit for safety. In addition to a regular reference count, Xen also maintains a type reference count. e.g. SegDesc (referenced by vGDT/vLDT), Writable (referenced with _PAGE_RW) or L{1..4} (referenced by vCR3 or a lower pagetable level). This is in order to prevent e.g. a page being inserted into the pagetables for which the guest has a writable mapping. For non-present mappings, all other bits become software accessible, and typically contain metadata rather a real frame address. There is nothing that a reference count could sensibly be tied to. As such, even if Xen could recognise the address as currently safe, nothing would prevent that frame from changing owner to another VM in the future. When Xen detects a PV guest writing a L1TF-PTE, it responds by activating shadow paging. This is normally only used for the live phase of migration, and comes with a reasonable overhead. KFENCE only cares about getting #PF to catch wild accesses; it doesn't care about the value for non-present mappings. Use a fully inverted PTE, to avoid hitting the slow path when running under Xen. While adjusting the logic, take the opportunity to skip all actions if the PTE is already in the right state, half the number PVOps callouts, and skip TLB maintenance on a !P -> P transition which benefits non-Xen cases too. Link: https://lkml.kernel.org/r/20260106180426.710013-1-andrew.cooper3@citrix.com Fixes: 1dc0da6e9ec0 ("x86, kfence: enable KFENCE for x86") Signed-off-by: Andrew Cooper Tested-by: Marco Elver Cc: Alexander Potapenko Cc: Marco Elver Cc: Dmitry Vyukov Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Borislav Petkov Cc: Dave Hansen Cc: "H. Peter Anvin" Cc: Jann Horn Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman

x86: remove __range_not_ok()

2026-01-19T12:10:12+00:00

commit 36903abedfe8d419e90ce349b2b4ce6dc2883e17 upstream. The __range_not_ok() helper is an x86 (and sparc64) specific interface that does roughly the same thing as __access_ok(), but with different calling conventions. Change this to use the normal interface in order for consistency as we clean up all access_ok() implementations. This changes the limit from TASK_SIZE to TASK_SIZE_MAX, which Al points out is the right thing do do here anyway. The callers have to use __access_ok() instead of the normal access_ok() though, because on x86 that contains a WARN_ON_IN_IRQ() check that cannot be used inside of NMI context while tracing. The check in copy_code() is not needed any more, because this one is already done by copy_from_user_nmi(). Suggested-by: Al Viro Suggested-by: Christoph Hellwig Link: https://lore.kernel.org/lkml/YgsUKcXGR7r4nINj@zeniv-ca.linux.org.uk/ Signed-off-by: Arnd Bergmann Stable-dep-of: d319f344561d ("mm: Fix copy_from_user_nofault().") Signed-off-by: Thadeu Lima de Souza Cascardo Signed-off-by: Greg Kroah-Hartman

x86/ptrace: Always inline trivial accessors

2026-01-19T12:09:41+00:00

[ Upstream commit 1fe4002cf7f23d70c79bda429ca2a9423ebcfdfa ] A KASAN build bloats these single load/store helpers such that it fails to inline them: vmlinux.o: error: objtool: irqentry_exit+0x5e8: call to instruction_pointer_set() with UACCESS enabled Make sure the compiler isn't allowed to do stupid. Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Link: https://patch.msgid.link/20251031105435.GU4068168@noisy.programming.kicks-ass.net Signed-off-by: Sasha Levin