Merge patch series "mm/mm_init: don't overlap zones with kernelcore=mirror"

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Mike Rapoport <rppt@kernel.org> says:

Make the behaviour of kernelcore= parameter uniform and treat mirror
just as another way to size the zones and cleanup a weird part of the
memory map initialization.

For example, for the memory layout below with the first two memory
ranges being mirrored (flags=0x2)

  memory[0x0]     [0x0000000000001000-0x000000000009efff], 0x000000000009e000 bytes on node 0 flags: 0x2
  memory[0x1]     [0x0000000000100000-0x00000000bffdefff], 0x00000000bfedf000 bytes on node 0 flags: 0x2
  memory[0x2]     [0x0000000100000000-0x000000013fffffff], 0x0000000040000000 bytes on node 0 flags: 0x2
  memory[0x3]     [0x0000000140000000-0x00000001bfffffff], 0x0000000080000000 bytes on node 0 flags: 0x0

with kernelcore=mirror set zone ranges would be

  Normal  [100000, 1c0000]
  Movable [140000, 1c0000]

and range [140000, 1c0000] is spanned by both NORMAL and MOVABLE zones.

This range will be passed twice to memmap_init_range() - once for each
zone that spans it.
The memory map for this range will be initialized as ZONE_NORMAL during the
first pass and skipped because of overlap_memmap_init() during the second
pass (ZONE_MOVABLE initialization), although the pages in this range
actually belong to ZONE_MOVABLE.

Aligning kernelcore=mirror behaviour with other variants of
kernelcore=/movablecore= resolves this issue and makes the code less
obfuscated.

patches from https://patch.msgid.link/20260630072212.624305-1-rppt@kernel.org
  mm/mm_init: don't overlap NORMAL and MOVABLE zones with kernelcore=mirror
  mm/mm_init: drop overlap_memmap_init()

Link: https://patch.msgid.link/20260630072212.624305-1-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>

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This commit is contained in:

Mike Rapoport (Microsoft) 2026-07-02 09:26:57 +03:00

parent 7783dcd79a f042b69ebb

commit b69c2a1fa9

1 changed files with 3 additions and 57 deletions

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mm/mm_init.c

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