1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _ASM_X86_SPARSEMEM_H
3#define _ASM_X86_SPARSEMEM_H
4
5#ifdef CONFIG_SPARSEMEM
6/*
7 * generic non-linear memory support:
8 *
9 * 1) we will not split memory into more chunks than will fit into the flags
10 * field of the struct page
11 *
12 * SECTION_SIZE_BITS 2^n: size of each section
13 * MAX_PHYSMEM_BITS 2^n: max size of physical address space
14 *
15 */
16
17#ifdef CONFIG_X86_32
18# ifdef CONFIG_X86_PAE
19# define SECTION_SIZE_BITS 29
20# define MAX_PHYSMEM_BITS 36
21# else
22# define SECTION_SIZE_BITS 26
23# define MAX_PHYSMEM_BITS 32
24# endif
25#else /* CONFIG_X86_32 */
26# define SECTION_SIZE_BITS 27 /* matt - 128 is convenient right now */
27# define MAX_PHYSMEM_BITS (pgtable_l5_enabled() ? 52 : 46)
28#endif
29
30#endif /* CONFIG_SPARSEMEM */
31
32#ifndef __ASSEMBLY__
33#ifdef CONFIG_NUMA_KEEP_MEMINFO
34extern int phys_to_target_node(phys_addr_t start);
35#define phys_to_target_node phys_to_target_node
36extern int memory_add_physaddr_to_nid(u64 start);
37#define memory_add_physaddr_to_nid memory_add_physaddr_to_nid
38#endif
39#endif /* __ASSEMBLY__ */
40
41#endif /* _ASM_X86_SPARSEMEM_H */
42

source code of linux/arch/x86/include/asm/sparsemem.h