LoongArch: add sparse memory vmemmap support

Add sparse memory vmemmap support for LoongArch.  SPARSEMEM_VMEMMAP uses a
virtually mapped memmap to optimise pfn_to_page and page_to_pfn
operations.  This is the most efficient option when sufficient kernel
resources are available.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Min Zhou <[email protected]>
Signed-off-by: Feiyang Chen <[email protected]>
Signed-off-by: Huacai Chen <[email protected]>
Reviewed-by: Arnd Bergmann <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Dinh Nguyen <[email protected]>
Cc: Guo Ren <[email protected]>
Cc: Jiaxun Yang <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Philippe Mathieu-Daudé <[email protected]>
Cc: Thomas Bogendoerfer <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Xuefeng Li <[email protected]>
Cc: Xuerui Wang <[email protected]>
Cc: Muchun Song <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

1 files changed, 2 insertions, 0 deletions

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 767c8c522e70..7c31f898337c 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -3360,6 +3360,8 @@ void *sparse_buffer_alloc(unsigned long size);
 struct page * __populate_section_memmap(unsigned long pfn,
 		unsigned long nr_pages, int nid, struct vmem_altmap *altmap,
 		struct dev_pagemap *pgmap);
+void pmd_init(void *addr);
+void pud_init(void *addr);
 pgd_t *vmemmap_pgd_populate(unsigned long addr, int node);
 p4d_t *vmemmap_p4d_populate(pgd_t *pgd, unsigned long addr, int node);
 pud_t *vmemmap_pud_populate(p4d_t *p4d, unsigned long addr, int node);