[PATCH v2 5/9] kho: add read-only Kexec Handover mode

[sashiko-bot at kernel.org]

> Kernels that inspect preserved KHO state without taking ownership of
> preserved memory need a way to traverse the KHO FDT, radix tree, and
> vmalloc chains in place while leaving the underlying physical pages and
> metadata unmodified.
> 
> Add CONFIG_KEXEC_HANDOVER_READONLY and the 'kho_ro=<pa>' kernel
> command-line parameter so both regular KHO and read-only KHO can be
> compiled into the same kernel image and activated via the command line.
> Map and validate the incoming KHO FDT once in an early_initcall, and
> cache radix-tree node, leaf, folio, and vmalloc mappings in a unified
> RCU-protected hash table (kho_ro_map_ht) for the lifetime of the
> read-only KHO kernel.
> 
> Also export kho_is_ro(), kho_ro_lookup_folio_order(),
> kho_ro_map_folio(), and kho_ro_map_vmalloc() so callers can check if
> read-only KHO mode is active and map preserved folios and vmalloc
> regions verified against the KHO radix tree.
> 
> Signed-off-by: Pasha Tatashin <pasha.tatashin at soleen.com>

Sashiko has reviewed this patch and found no issues.

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Sashiko AI review · https://sashiko.dev/#/patchset/20261025174017.3870481-1-pasha.tatashin@soleen.com?part=5