On Mon, 28 Aug 2023 13:16:57 +0530, Aneesh Kumar K.V wrote:

With CONFIG_SPARSEMEM disabled the below kernel build error is observed.

 arch/powerpc/mm/init_64.c:477:38: error: use of undeclared identifier 'SECTION_SIZE_BITS'

CONFIG_MEMORY_HOTPLUG depends on CONFIG_SPARSEMEM and it is more clear
to describe the code dependency in terms of MEMORY_HOTPLUG. Outside
memory hotplug the kernel uses memory_block_size for kernel directmap.
Instead of depending on SECTION_SIZE_BITS to compute the direct map
page size, add a new #define which defaults to 16M(same as existing
SECTION_SIZE)

[...]

Applied to powerpc/next.

[1/2] powerpc/mm/book3s64: Fix build error with SPARSEMEM disabled
      https://git.kernel.org/powerpc/c/f1424755db913c5971686537381588261cdfd1ee
[2/2] powerpc/mm/book3s64: Use 256M as the upper limit with coherent device memory attached
      https://git.kernel.org/powerpc/c/4c33bf147249ebbf3dded016996a8a24c5737254

cheers