The recently added MIPS cacheinfo support used a macro populate_cache()
to populate the cacheinfo structures depending on which caches are
present. However the macro contains multiple statements without
enclosing them in a do {} while (0) loop, so the L2 and L3 cache
conditionals in populate_cache_leaves() only conditionalised the first
statement in the macro.
This overflows the buffer allocated by detect_cache_attributes(),
resulting in boot failures under QEMU where neither the L2 or L2 caches
are present.
Enclose the macro statements in a do {} while (0) block to keep the
whole macro inside the conditionals.