Re: [PATCH 1/4] riscv: Call early_ioremap_setup() before parsing the DTB

[sashiko-bot@kernel.org]

> early_ioremap_setup() fills in the slot_virt[] array whose entries the
> return value of early_ioremap()/early_memremap() is composed from.  On
> RISC-V it ran after parse_dtb(), so an early_memremap() reached from
> the device tree scan returned "offset + 0" -- NULL for a page aligned
> address -- and the caller could only report a mapping failure.  This
> stayed latent because nothing reached from parse_dtb() asked for an
> early mapping before; the DT based kexec handover parsing is the first
> such caller, as kho_populate() maps the handover FDT and the scratch
> descriptor array with early_memremap().
> 
> Move the call to the top of setup_arch(), which is how arm64 and x86
> already order it (early_fixmap_init()/early_ioremap_init() before
> setup_machine_fdt()/parse_setup_data()).  The BTMAP window is mapped
> into early_pg_dir by setup_vm(), and RISC-V neither calls
> early_ioremap_reset() nor defines __late_set_fixmap(), so the virtual
> addresses stay identical across the switch to the final page tables
> and nothing else in setup_arch() depends on the previous ordering.
> 
> Signed-off-by: Chen Pei <cp0613@linux.alibaba.com>

Sashiko has reviewed this patch and found no issues.

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Sashiko AI review · https://sashiko.dev/#/patchset/20261023111612.2134-1-cp0613@linux.alibaba.com?part=1