linux/arch/arm64/mm
Ard Biesheuvel 97d6786e06 arm64: mm: account for hotplug memory when randomizing the linear region
As a hardening measure, we currently randomize the placement of
physical memory inside the linear region when KASLR is in effect.
Since the random offset at which to place the available physical
memory inside the linear region is chosen early at boot, it is
based on the memblock description of memory, which does not cover
hotplug memory. The consequence of this is that the randomization
offset may be chosen such that any hotplugged memory located above
memblock_end_of_DRAM() that appears later is pushed off the end of
the linear region, where it cannot be accessed.

So let's limit this randomization of the linear region to ensure
that this can no longer happen, by using the CPU's addressable PA
range instead. As it is guaranteed that no hotpluggable memory will
appear that falls outside of that range, we can safely put this PA
range sized window anywhere in the linear region.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Steven Price <steven.price@arm.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/20201014081857.3288-1-ardb@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2020-11-10 18:43:25 +00:00
..
cache.S arm64: mm: Use modern annotations for assembly functions 2020-01-08 12:23:38 +00:00
context.c arm64: mm: Pin down ASIDs for sharing mm with devices 2020-09-28 22:15:38 +01:00
copypage.c arm64: Avoid unnecessary clear_user_page() indirection 2020-09-04 12:46:06 +01:00
dma-mapping.c dma-mapping: merge <linux/dma-noncoherent.h> into <linux/dma-map-ops.h> 2020-10-06 07:07:06 +02:00
extable.c arm64: Improve diagnostics when trapping BRK with FAULT_BRK_IMM 2020-09-18 16:35:54 +01:00
fault.c arm64: Add workaround for Arm Cortex-A77 erratum 1508412 2020-10-29 12:56:01 +00:00
flush.c mm: introduce page_size() 2019-09-24 15:54:08 -07:00
hugetlbpage.c mm: remove unneeded includes of <asm/pgalloc.h> 2020-08-07 11:33:26 -07:00
init.c arm64: mm: account for hotplug memory when randomizing the linear region 2020-11-10 18:43:25 +00:00
ioremap.c mm: remove unneeded includes of <asm/pgalloc.h> 2020-08-07 11:33:26 -07:00
kasan_init.c arch, drivers: replace for_each_membock() with for_each_mem_range() 2020-10-13 18:38:35 -07:00
Makefile Merge branch 'for-next/mte' into for-next/core 2020-10-02 12:16:11 +01:00
mmap.c arm64, mm: move generic mmap layout functions to mm 2019-09-24 15:54:11 -07:00
mmu.c treewide: Convert macro and uses of __section(foo) to __section("foo") 2020-10-25 14:51:49 -07:00
mteswap.c arm64: mte: Enable swap of tagged pages 2020-09-04 12:46:07 +01:00
numa.c memblock: use separate iterators for memory and reserved regions 2020-10-13 18:38:35 -07:00
pageattr.c arm64: mm: Fix missing-prototypes in pageattr.c 2020-09-18 14:33:46 +01:00
pgd.c mm: consolidate pgtable_cache_init() and pgd_cache_init() 2019-09-24 15:54:09 -07:00
physaddr.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
proc.S arm64: mte: CPU feature detection and initial sysreg configuration 2020-09-03 17:26:32 +01:00
ptdump_debugfs.c arm64/mm: Hold memory hotplug lock while walking for kernel page table dump 2020-03-04 15:35:22 +00:00
ptdump.c Merge branch 'for-next/mte' into for-next/core 2020-10-02 12:16:11 +01:00