From: Ard Biesheuvel Date: Wed, 25 Feb 2026 11:03:04 +0000 (+0100) Subject: efi: Tag memblock reservations of boot services regions as RSRV_KERN X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=259e3e6f9382b6a9fe570313d97c59a233f7d72f;p=thirdparty%2Fkernel%2Flinux.git efi: Tag memblock reservations of boot services regions as RSRV_KERN By definition, EFI memory regions of type boot services code or data have no special significance to the firmware at runtime, only to the OS. In some cases, the firmware will allocate tables and other assets that are passed in memory in regions of this type, and leave it up to the OS to decide whether or not to treat the allocation as special, or simply consume the contents at boot and recycle the RAM for ordinary use. The reason for this approach is that it avoids needless memory reservations for assets that the OS knows nothing about, and therefore doesn't know how to free either. This means that any memblock reservations covering such regions can be marked as MEMBLOCK_RSRV_KERN - this is a better match semantically, and is useful on x86 to distinguish true reservations from temporary reservations that are only needed to work around firmware bugs. Acked-by: Mike Rapoport (Microsoft) Signed-off-by: Ard Biesheuvel --- diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c index 288834a193d10..8600dd31a5868 100644 --- a/drivers/firmware/efi/efi.c +++ b/drivers/firmware/efi/efi.c @@ -600,7 +600,9 @@ void __init efi_mem_reserve(phys_addr_t addr, u64 size) return; if (!memblock_is_region_reserved(addr, size)) - memblock_reserve(addr, size); + memblock_reserve_kern(addr, size); + else + memblock_reserved_mark_kern(addr, size); /* * Some architectures (x86) reserve all boot services ranges