kernel/drivers/firmware/efi/memmap.c, branch linux-6.18.y

efi: Improve logging around memmap init

2025-05-09T09:07:28Z

Be more informative if memremap fails, and print out physical address together with size. This change intends to make investigations of such early failures slightly easier. Signed-off-by: Bartosz Szczepanek Signed-off-by: Ard Biesheuvel

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

2024-06-15T08:25:02Z

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

efi: memmap: fix kernel-doc warnings

2023-12-22T09:42:06Z

Correct all kernel-doc notation to repair warnings that are reported by scripts/kernel-doc: memmap.c:38: warning: No description found for return value of '__efi_memmap_init' memmap.c:82: warning: No description found for return value of 'efi_memmap_init_early' memmap.c:132: warning: Function parameter or member 'addr' not described in 'efi_memmap_init_late' memmap.c:132: warning: Excess function parameter 'phys_addr' description in 'efi_memmap_init_late' memmap.c:132: warning: No description found for return value of 'efi_memmap_init_late' Signed-off-by: Randy Dunlap Cc: Ard Biesheuvel Cc: linux-efi@vger.kernel.org Signed-off-by: Ard Biesheuvel

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

2022-11-18T08:14:09Z

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

efi: memmap: Move manipulation routines into x86 arch tree

2022-11-18T08:14:09Z

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. Signed-off-by: Ard Biesheuvel

drivers: fix typo in firmware/efi/memmap.c

2022-06-28T18:00:11Z

This patch fixes the spelling error in firmware/efi/memmap.c, changing it to the correct word. Signed-off-by: Zheng Zhi Yuan Signed-off-by: Ard Biesheuvel

efi: Correct comment on efi_memmap_alloc

2022-06-15T15:48:58Z

Returning zero means success now. Signed-off-by: Liu Zixian Signed-off-by: Ard Biesheuvel

memblock: rename memblock_free to memblock_phys_free

2021-11-06T20:30:41Z

Since memblock_free() operates on a physical range, make its name reflect it and rename it to memblock_phys_free(), so it will be a logical counterpart to memblock_phys_alloc(). The callers are updated with the below semantic patch: @@ expression addr; expression size; @@ - memblock_free(addr, size); + memblock_phys_free(addr, size); Link: https://lkml.kernel.org/r/20210930185031.18648-6-rppt@kernel.org Signed-off-by: Mike Rapoport Cc: Christophe Leroy Cc: Juergen Gross Cc: Shahab Vahedi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

efi: Fix handling of multiple efi_fake_mem= entries

2020-01-20T07:14:29Z

Dave noticed that when specifying multiple efi_fake_mem= entries only the last entry was successfully being reflected in the efi memory map. This is due to the fact that the efi_memmap_insert() is being called multiple times, but on successive invocations the insertion should be applied to the last new memmap rather than the original map at efi_fake_memmap() entry. Rework efi_fake_memmap() to install the new memory map after each efi_fake_mem= entry is parsed. This also fixes an issue in efi_fake_memmap() that caused it to litter emtpy entries into the end of the efi memory map. An empty entry causes efi_memmap_insert() to attempt more memmap splits / copies than efi_memmap_split_count() accounted for when sizing the new map. When that happens efi_memmap_insert() may overrun its allocation, and if you are lucky will spill over to an unmapped page leading to crash signature like the following rather than silent corruption: BUG: unable to handle page fault for address: ffffffffff281000 [..] RIP: 0010:efi_memmap_insert+0x11d/0x191 [..] Call Trace: ? bgrt_init+0xbe/0xbe ? efi_arch_mem_reserve+0x1cb/0x228 ? acpi_parse_bgrt+0xa/0xd ? acpi_table_parse+0x86/0xb8 ? acpi_boot_init+0x494/0x4e3 ? acpi_parse_x2apic+0x87/0x87 ? setup_acpi_sci+0xa2/0xa2 ? setup_arch+0x8db/0x9e1 ? start_kernel+0x6a/0x547 ? secondary_startup_64+0xb6/0xc0 Commit af1648984828 "x86/efi: Update e820 with reserved EFI boot services data to fix kexec breakage" introduced more occurrences where efi_memmap_insert() is invoked after an efi_fake_mem= configuration has been parsed. Previously the side effects of vestigial empty entries were benign, but with commit af1648984828 that follow-on efi_memmap_insert() invocation triggers efi_memmap_insert() overruns. Reported-by: Dave Young Signed-off-by: Dan Williams Signed-off-by: Ard Biesheuvel Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/20191231014630.GA24942@dhcp-128-65.nay.redhat.com Link: https://lore.kernel.org/r/20200113172245.27925-14-ardb@kernel.org

efi: Fix efi_memmap_alloc() leaks

2020-01-20T07:14:29Z

With efi_fake_memmap() and efi_arch_mem_reserve() the efi table may be updated and replaced multiple times. When that happens a previous dynamically allocated efi memory map can be garbage collected. Use the new EFI_MEMMAP_{SLAB,MEMBLOCK} flags to detect when a dynamically allocated memory map is being replaced. Debug statements in efi_memmap_free() reveal: efi: __efi_memmap_free:37: phys: 0x23ffdd580 size: 2688 flags: 0x2 efi: __efi_memmap_free:37: phys: 0x9db00 size: 2640 flags: 0x2 efi: __efi_memmap_free:37: phys: 0x9e580 size: 2640 flags: 0x2 ...a savings of 7968 bytes on a qemu boot with 2 entries specified to efi_fake_mem=. [ ardb: added a comment to clarify that efi_memmap_free() does nothing when called from efi_clean_memmap(), i.e., with data->flags == 0x0 ] Signed-off-by: Dan Williams Signed-off-by: Ard Biesheuvel Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/20200113172245.27925-13-ardb@kernel.org