> +/* > + * Log2 of the upper bound of the size of a struct page. Used for sizing > + * the vmemmap region only, does not affect actual memory footprint. > + * We don't use sizeof(struct page) directly since taking its size here > + * requires its definition to be available at this point in the inclusion > + * chain, and it may not be a power of 2 in the first place. > + */ > +#define STRUCT_PAGE_MAX_SHIFT 6 I know this is copied from arm64, but wouldn't this be a good time to move this next to the struct page defintion? Also this: arch/arm64/mm/init.c: BUILD_BUG_ON(sizeof(struct page) > (1 << STRUCT_PAGE_MAX_SHIFT)); should move to comment code (or would have to be duplicated for riscv) > +#define VMEMMAP_SIZE (UL(1) << (CONFIG_VA_BITS - PAGE_SHIFT - 1 + \ > + STRUCT_PAGE_MAX_SHIFT)) Might be more readable with a another define, and without abuse of the horrible UL macro: #define VMEMMAP_SHIFT \ (CONFIG_VA_BITS - PAGE_SHIFT - 1 + STRUCT_PAGE_MAX_SHIFT) #define VMEMMAP_SIZE (1UL << VMEMMAP_SHIFT) > +#define VMEMMAP_END (VMALLOC_START - 1) > +#define VMEMMAP_START (VMALLOC_START - VMEMMAP_SIZE) > + > +#define vmemmap ((struct page *)VMEMMAP_START) This could also use some comments.. > @@ -0,0 +1,11 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > + > +#ifndef __ASM_SPARSEMEM_H > +#define __ASM_SPARSEMEM_H > + > +#ifdef CONFIG_SPARSEMEM > +#define MAX_PHYSMEM_BITS CONFIG_PA_BITS > +#define SECTION_SIZE_BITS 30 > +#endif > + > +#endif For potentially wide-spanning ifdefs like inclusion headers it always is nice to have a comment with the symbol on the endif line.
