1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef __LINUX_PERCPU_H
3#define __LINUX_PERCPU_H
4
5#include <linux/mmdebug.h>
6#include <linux/preempt.h>
7#include <linux/smp.h>
8#include <linux/cpumask.h>
9#include <linux/pfn.h>
10#include <linux/init.h>
11#include <linux/cleanup.h>
12
13#include <asm/percpu.h>
14
15/* enough to cover all DEFINE_PER_CPUs in modules */
16#ifdef CONFIG_MODULES
17#define PERCPU_MODULE_RESERVE (8 << 10)
18#else
19#define PERCPU_MODULE_RESERVE 0
20#endif
21
22/* minimum unit size, also is the maximum supported allocation size */
23#define PCPU_MIN_UNIT_SIZE PFN_ALIGN(32 << 10)
24
25/* minimum allocation size and shift in bytes */
26#define PCPU_MIN_ALLOC_SHIFT 2
27#define PCPU_MIN_ALLOC_SIZE (1 << PCPU_MIN_ALLOC_SHIFT)
28
29/*
30 * The PCPU_BITMAP_BLOCK_SIZE must be the same size as PAGE_SIZE as the
31 * updating of hints is used to manage the nr_empty_pop_pages in both
32 * the chunk and globally.
33 */
34#define PCPU_BITMAP_BLOCK_SIZE PAGE_SIZE
35#define PCPU_BITMAP_BLOCK_BITS (PCPU_BITMAP_BLOCK_SIZE >> \
36 PCPU_MIN_ALLOC_SHIFT)
37
38#ifdef CONFIG_RANDOM_KMALLOC_CACHES
39#define PERCPU_DYNAMIC_SIZE_SHIFT 12
40#else
41#define PERCPU_DYNAMIC_SIZE_SHIFT 10
42#endif
43
44/*
45 * Percpu allocator can serve percpu allocations before slab is
46 * initialized which allows slab to depend on the percpu allocator.
47 * The following parameter decide how much resource to preallocate
48 * for this. Keep PERCPU_DYNAMIC_RESERVE equal to or larger than
49 * PERCPU_DYNAMIC_EARLY_SIZE.
50 */
51#define PERCPU_DYNAMIC_EARLY_SIZE (20 << PERCPU_DYNAMIC_SIZE_SHIFT)
52
53/*
54 * PERCPU_DYNAMIC_RESERVE indicates the amount of free area to piggy
55 * back on the first chunk for dynamic percpu allocation if arch is
56 * manually allocating and mapping it for faster access (as a part of
57 * large page mapping for example).
58 *
59 * The following values give between one and two pages of free space
60 * after typical minimal boot (2-way SMP, single disk and NIC) with
61 * both defconfig and a distro config on x86_64 and 32. More
62 * intelligent way to determine this would be nice.
63 */
64#if BITS_PER_LONG > 32
65#define PERCPU_DYNAMIC_RESERVE (28 << PERCPU_DYNAMIC_SIZE_SHIFT)
66#else
67#define PERCPU_DYNAMIC_RESERVE (20 << PERCPU_DYNAMIC_SIZE_SHIFT)
68#endif
69
70extern void *pcpu_base_addr;
71extern const unsigned long *pcpu_unit_offsets;
72
73struct pcpu_group_info {
74 int nr_units; /* aligned # of units */
75 unsigned long base_offset; /* base address offset */
76 unsigned int *cpu_map; /* unit->cpu map, empty
77 * entries contain NR_CPUS */
78};
79
80struct pcpu_alloc_info {
81 size_t static_size;
82 size_t reserved_size;
83 size_t dyn_size;
84 size_t unit_size;
85 size_t atom_size;
86 size_t alloc_size;
87 size_t __ai_size; /* internal, don't use */
88 int nr_groups; /* 0 if grouping unnecessary */
89 struct pcpu_group_info groups[];
90};
91
92enum pcpu_fc {
93 PCPU_FC_AUTO,
94 PCPU_FC_EMBED,
95 PCPU_FC_PAGE,
96
97 PCPU_FC_NR,
98};
99extern const char * const pcpu_fc_names[PCPU_FC_NR];
100
101extern enum pcpu_fc pcpu_chosen_fc;
102
103typedef int (pcpu_fc_cpu_to_node_fn_t)(int cpu);
104typedef int (pcpu_fc_cpu_distance_fn_t)(unsigned int from, unsigned int to);
105
106extern struct pcpu_alloc_info * __init pcpu_alloc_alloc_info(int nr_groups,
107 int nr_units);
108extern void __init pcpu_free_alloc_info(struct pcpu_alloc_info *ai);
109
110extern void __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
111 void *base_addr);
112
113extern int __init pcpu_embed_first_chunk(size_t reserved_size, size_t dyn_size,
114 size_t atom_size,
115 pcpu_fc_cpu_distance_fn_t cpu_distance_fn,
116 pcpu_fc_cpu_to_node_fn_t cpu_to_nd_fn);
117
118#ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK
119void __init pcpu_populate_pte(unsigned long addr);
120extern int __init pcpu_page_first_chunk(size_t reserved_size,
121 pcpu_fc_cpu_to_node_fn_t cpu_to_nd_fn);
122#endif
123
124extern void __percpu *__alloc_reserved_percpu(size_t size, size_t align) __alloc_size(1);
125extern bool __is_kernel_percpu_address(unsigned long addr, unsigned long *can_addr);
126extern bool is_kernel_percpu_address(unsigned long addr);
127
128#if !defined(CONFIG_SMP) || !defined(CONFIG_HAVE_SETUP_PER_CPU_AREA)
129extern void __init setup_per_cpu_areas(void);
130#endif
131
132extern void __percpu *__alloc_percpu_gfp(size_t size, size_t align, gfp_t gfp) __alloc_size(1);
133extern void __percpu *__alloc_percpu(size_t size, size_t align) __alloc_size(1);
134extern void free_percpu(void __percpu *__pdata);
135extern size_t pcpu_alloc_size(void __percpu *__pdata);
136
137DEFINE_FREE(free_percpu, void __percpu *, free_percpu(_T))
138
139extern phys_addr_t per_cpu_ptr_to_phys(void *addr);
140
141#define alloc_percpu_gfp(type, gfp) \
142 (typeof(type) __percpu *)__alloc_percpu_gfp(sizeof(type), \
143 __alignof__(type), gfp)
144#define alloc_percpu(type) \
145 (typeof(type) __percpu *)__alloc_percpu(sizeof(type), \
146 __alignof__(type))
147
148extern unsigned long pcpu_nr_pages(void);
149
150#endif /* __LINUX_PERCPU_H */
151

source code of linux/include/linux/percpu.h