[RFC PATCH 2/2] memblock: don't allocate reserve_mem regions from KHO bootmem

[sashiko-bot at kernel.org]

> On a KHO boot, a reserve_mem region that can't be revived is allocated
> from KHO_NOPRSRV memory, which includes the bootmem the next kernel
> boots out of. With CONFIG_KEXEC_HANDOVER_DEBUG, preserving the region
> then fails:
> 
>   WARNING: kernel/liveupdate/kexec_handover.c:1245 at kho_preserve_pages+0x168/0x180
>   failed to prepare memblock FDT for KHO: -22
> 
> Without it, the next kernel puts its memmap on top of the region and
> the ramoops records in it are lost.
> 
> Use the search that keeps HugeTLB pages out of bootmem, and keep the
> mirrored memory fallback of memblock_phys_alloc().
> 
> Fixes: f99230780211 ("memblock: add KHO support for reserve_mem")
> Signed-off-by: Jose A. Perez de Azpillaga <azpijr at gmail.com>

Sashiko has reviewed this patch and found no issues.

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