kernel/linux.git/arch/x86/platform, branch v5.15.208

x86/efi: efi_unmap_boot_services: fix calculation of ranges_to_free size

2026-04-18T08:33:26+00:00

[ Upstream commit 217c0a5c177a3d4f7c8497950cbf5c36756e8bbb ] ranges_to_free array should have enough room to store the entire EFI memmap plus an extra element for NULL entry. The calculation of this array size wrongly adds 1 to the overall size instead of adding 1 to the number of elements. Add parentheses to properly size the array. Reported-by: Guenter Roeck Fixes: a4b0bf6a40f3 ("x86/efi: defer freeing of boot services memory") Signed-off-by: Mike Rapoport (Microsoft) Signed-off-by: Ard Biesheuvel Signed-off-by: Sasha Levin

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/xen/pvh: Enable PAE mode for 32-bit guest only when CONFIG_X86_PAE is set

2026-03-04T12:19:58+00:00

[ Upstream commit db9aded979b491a24871e1621cd4e8822dbca859 ] The PVH entry is available for 32-bit KVM guests, and 32-bit KVM guests do not depend on CONFIG_X86_PAE. However, mk_early_pgtbl_32() builds different pagetables depending on whether CONFIG_X86_PAE is set. Therefore, enabling PAE mode for 32-bit KVM guests without CONFIG_X86_PAE being set would result in a boot failure during CR3 loading. Signed-off-by: Hou Wenlong Reviewed-by: Juergen Gross Signed-off-by: Juergen Gross Message-ID: Signed-off-by: Sasha Levin

x86/pvh: Call C code via the kernel virtual mapping

2025-05-02T05:44:18+00:00

commit e8fbc0d9cab6c1ee6403f42c0991b0c1d5dbc092 upstream. Calling C code via a different mapping than it was linked at is problematic, because the compiler assumes that RIP-relative and absolute symbol references are interchangeable. GCC in particular may use RIP-relative per-CPU variable references even when not using -fpic. So call xen_prepare_pvh() via its kernel virtual mapping on x86_64, so that those RIP-relative references produce the correct values. This matches the pre-existing behavior for i386, which also invokes xen_prepare_pvh() via the kernel virtual mapping before invoking startup_32 with paging disabled again. Fixes: 7243b93345f7 ("xen/pvh: Bootstrap PVH guest") Tested-by: Jason Andryuk Reviewed-by: Jason Andryuk Signed-off-by: Ard Biesheuvel Message-ID: <20241009160438.3884381-8-ardb+git@google.com> Signed-off-by: Juergen Gross [ Stable context update ] Signed-off-by: Jason Andryuk Signed-off-by: Greg Kroah-Hartman

x86/platform/iosf_mbi: Convert PCIBIOS_* return codes to errnos

2024-08-19T03:44:50+00:00

[ Upstream commit 7821fa101eab529521aa4b724bf708149d70820c ] iosf_mbi_pci_{read,write}_mdr() use pci_{read,write}_config_dword() that return PCIBIOS_* codes but functions also return -ENODEV which are not compatible error codes. As neither of the functions are related to PCI read/write functions, they should return normal errnos. Convert PCIBIOS_* returns code using pcibios_err_to_errno() into normal errno before returning it. Fixes: 46184415368a ("arch: x86: New MailBox support driver for Intel SOC's") Signed-off-by: Ilpo Järvinen Signed-off-by: Borislav Petkov (AMD) Link: https://lore.kernel.org/r/20240527125538.13620-4-ilpo.jarvinen@linux.intel.com Signed-off-by: Sasha Levin

efi/x86: Free EFI memory map only when installing a new one.

2024-07-05T07:14:51+00:00

[ Commit 75dde792d6f6c2d0af50278bd374bf0c512fe196 upstream ] The logic in __efi_memmap_init() is shared between two different execution flows: - mapping the EFI memory map early or late into the kernel VA space, so that its entries can be accessed; - the x86 specific cloning of the EFI memory map in order to insert new entries that are created as a result of making a memory reservation via a call to efi_mem_reserve(). In the former case, the underlying memory containing the kernel's view of the EFI memory map (which may be heavily modified by the kernel itself on x86) is not modified at all, and the only thing that changes is the virtual mapping of this memory, which is different between early and late boot. In the latter case, an entirely new allocation is created that carries a new, updated version of the kernel's view of the EFI memory map. When installing this new version, the old version will no longer be referenced, and if the memory was allocated by the kernel, it will leak unless it gets freed. The logic that implements this freeing currently lives on the code path that is shared between these two use cases, but it should only apply to the latter. So move it to the correct spot. While at it, drop the dummy definition for non-x86 architectures, as that is no longer needed. Cc: Fixes: f0ef6523475f ("efi: Fix efi_memmap_alloc() leaks") Tested-by: Ashish Kalra Link: https://lore.kernel.org/all/36ad5079-4326-45ed-85f6-928ff76483d3@amd.com Signed-off-by: Ard Biesheuvel Signed-off-by: Greg Kroah-Hartman

efi: xen: Set EFI_PARAVIRT for Xen dom0 boot on all architectures

2024-07-05T07:14:51+00:00

[ Commit d85e3e34940788578eeffd94e8b7e1d28e7278e9 upstream ] Currently, the EFI_PARAVIRT flag is only used by Xen dom0 boot on x86, even though other architectures also support pseudo-EFI boot, where the core kernel is invoked directly and provided with a set of data tables that resemble the ones constructed by the EFI stub, which never actually runs in that case. Let's fix this inconsistency, and always set this flag when booting dom0 via the EFI boot path. Note that Xen on x86 does not provide the EFI memory map in this case, whereas other architectures do, so move the associated EFI_PARAVIRT check into the x86 platform code. Signed-off-by: Ard Biesheuvel Signed-off-by: Greg Kroah-Hartman

efi: memmap: Move manipulation routines into x86 arch tree

2024-07-05T07:14:51+00:00

[ Commit fdc6d38d64a20c542b1867ebeb8dd03b98829336 upstream ] The EFI memory map is a description of the memory layout as provided by the firmware, and only x86 manipulates it in various different ways for its own memory bookkeeping. So let's move the memmap routines that are only used by x86 into the x86 arch tree. [ardb: s/memblock_phys_free/memblock_free for linux-5.15.y backport] Signed-off-by: Ard Biesheuvel Signed-off-by: Greg Kroah-Hartman

x86/olpc: fix 'logical not is only applied to the left hand side'

2022-08-17T12:24:18+00:00

commit 3a2ba42cbd0b669ce3837ba400905f93dd06c79f upstream. The bitops compile-time optimization series revealed one more problem in olpc-xo1-sci.c:send_ebook_state(), resulted in GCC warnings: arch/x86/platform/olpc/olpc-xo1-sci.c: In function 'send_ebook_state': arch/x86/platform/olpc/olpc-xo1-sci.c:83:63: warning: logical not is only applied to the left hand side of comparison [-Wlogical-not-parentheses] 83 | if (!!test_bit(SW_TABLET_MODE, ebook_switch_idev->sw) == state) | ^~ arch/x86/platform/olpc/olpc-xo1-sci.c:83:13: note: add parentheses around left hand side expression to silence this warning Despite this code working as intended, this redundant double negation of boolean value, together with comparing to `char` with no explicit conversion to bool, makes compilers think the author made some unintentional logical mistakes here. Make it the other way around and negate the char instead to silence the warnings. Fixes: d2aa37411b8e ("x86/olpc/xo1/sci: Produce wakeup events for buttons and switches") Cc: stable@vger.kernel.org # 3.5+ Reported-by: Guenter Roeck Reported-by: kernel test robot Reviewed-and-tested-by: Guenter Roeck Signed-off-by: Alexander Lobakin Signed-off-by: Yury Norov Signed-off-by: Greg Kroah-Hartman

efi/x86: use naked RET on mixed mode call wrapper

2022-07-23T10:54:12+00:00

commit 51a6fa0732d6be6a44e0032752ad2ac10d67c796 upstream. When running with return thunks enabled under 32-bit EFI, the system crashes with: kernel tried to execute NX-protected page - exploit attempt? (uid: 0) BUG: unable to handle page fault for address: 000000005bc02900 #PF: supervisor instruction fetch in kernel mode #PF: error_code(0x0011) - permissions violation PGD 18f7063 P4D 18f7063 PUD 18ff063 PMD 190e063 PTE 800000005bc02063 Oops: 0011 [#1] PREEMPT SMP PTI CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.19.0-rc6+ #166 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 RIP: 0010:0x5bc02900 Code: Unable to access opcode bytes at RIP 0x5bc028d6. RSP: 0018:ffffffffb3203e10 EFLAGS: 00010046 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000048 RDX: 000000000190dfac RSI: 0000000000001710 RDI: 000000007eae823b RBP: ffffffffb3203e70 R08: 0000000001970000 R09: ffffffffb3203e28 R10: 747563657865206c R11: 6c6977203a696665 R12: 0000000000001710 R13: 0000000000000030 R14: 0000000001970000 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff8e013ca00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0018 ES: 0018 CR0: 0000000080050033 CR2: 000000005bc02900 CR3: 0000000001930000 CR4: 00000000000006f0 Call Trace: ? efi_set_virtual_address_map+0x9c/0x175 efi_enter_virtual_mode+0x4a6/0x53e start_kernel+0x67c/0x71e x86_64_start_reservations+0x24/0x2a x86_64_start_kernel+0xe9/0xf4 secondary_startup_64_no_verify+0xe5/0xeb That's because it cannot jump to the return thunk from the 32-bit code. Using a naked RET and marking it as safe allows the system to proceed booting. Fixes: aa3d480315ba ("x86: Use return-thunk in asm code") Reported-by: Guenter Roeck Signed-off-by: Thadeu Lima de Souza Cascardo Cc: Peter Zijlstra (Intel) Cc: Borislav Petkov Cc: Josh Poimboeuf Cc: Tested-by: Guenter Roeck Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman