On Fri, 29 May 2026 17:01:51 +0200, Ard Biesheuvel wrote:
> One of the reasons the lack of randomization of the linear map on arm64
> is considered problematic is the fact that bootloaders adhering to the
> original arm64 boot protocol (i.e., a substantial fraction of all
> Android phones) may place the kernel at the base of DRAM, and therefore
> at the base of the non-randomized linear map. This puts a writable alias
> of the kernel's data and bss regions at a predictable location, removing
> the need for an attacker to guess where KASLR mapped the kernel.
>
> [...]
It would've been nice to hear from the ppc folks on patch 11, but I've
picked it up on the assumption that they'll love the negative diff stat.
Worst case, we can drop/revert stuff if they have late objections.
Applied to arm64 (for-next/mm), thanks!
[01/15] arm64: mm: Remove bogus stop condition from map_mem() loop
https://git.kernel.org/arm64/c/36ca7f4be809
[02/15] arm64: mm: Drop redundant pgd_t* argument from map_mem()
https://git.kernel.org/arm64/c/2e527667a3b9
[03/15] arm64: mm: Check for pud_/pmd_set_huge() failures on kernel mappings
https://git.kernel.org/arm64/c/8dd640d9233d
[04/15] arm64: mm: Preserve existing table mappings when mapping DRAM
https://git.kernel.org/arm64/c/a64293e993f6
[05/15] arm64: mm: Preserve non-contiguous descriptors when mapping DRAM
https://git.kernel.org/arm64/c/ecda73ae92ca
[06/15] arm64: mm: Permit contiguous descriptors to be manipulated
https://git.kernel.org/arm64/c/05c5c31e9d8d
[07/15] arm64: kfence: Avoid NOMAP tricks when mapping the early pool
https://git.kernel.org/arm64/c/dfd73e574d38
[08/15] arm64: mm: Permit contiguous attribute for preliminary mappings
https://git.kernel.org/arm64/c/28becb2c1d74
[09/15] arm64: Move fixmap and kasan page tables to end of kernel image
https://git.kernel.org/arm64/c/382a03e12eba
[10/15] arm64: mm: Don't abuse memblock NOMAP to check for overlaps
https://git.kernel.org/arm64/c/d672a4b72c95
[11/15] powerpc/code-patching: Avoid r/w mapping of the zero page
https://git.kernel.org/arm64/c/c0693153fb17
[12/15] sh: Drop cache flush of the zero page at boot
https://git.kernel.org/arm64/c/99bad3e992e2
[13/15] mm: Make empty_zero_page[] const
https://git.kernel.org/arm64/c/0aae825f1ed7
[14/15] arm64: mm: Map the kernel data/bss read-only in the linear map
https://git.kernel.org/arm64/c/f2ba877402e5
[15/15] arm64: mm: Unmap kernel data/bss entirely from the linear map
https://git.kernel.org/arm64/c/63e0b6a5b693
Cheers,
--
Will
https://fixes.arm64.dev
https://next.arm64.dev
https://will.arm64.dev
