1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef __LINUX_PERCPU_H
3#define __LINUX_PERCPU_H
4
5#include <linux/alloc_tag.h>
6#include <linux/mmdebug.h>
7#include <linux/preempt.h>
8#include <linux/smp.h>
9#include <linux/pfn.h>
10#include <linux/init.h>
11#include <linux/cleanup.h>
12#include <linux/sched.h>
13
14#include <asm/percpu.h>
15
16/* enough to cover all DEFINE_PER_CPUs in modules */
17#ifdef CONFIG_MODULES
18#define PERCPU_MODULE_RESERVE (8 << 10)
19#else
20#define PERCPU_MODULE_RESERVE 0
21#endif
22
23/* minimum unit size, also is the maximum supported allocation size */
24#define PCPU_MIN_UNIT_SIZE PFN_ALIGN(32 << 10)
25
26/* minimum allocation size and shift in bytes */
27#define PCPU_MIN_ALLOC_SHIFT 2
28#define PCPU_MIN_ALLOC_SIZE (1 << PCPU_MIN_ALLOC_SHIFT)
29
30/*
31 * The PCPU_BITMAP_BLOCK_SIZE must be the same size as PAGE_SIZE as the
32 * updating of hints is used to manage the nr_empty_pop_pages in both
33 * the chunk and globally.
34 */
35#define PCPU_BITMAP_BLOCK_SIZE PAGE_SIZE
36#define PCPU_BITMAP_BLOCK_BITS (PCPU_BITMAP_BLOCK_SIZE >> \
37 PCPU_MIN_ALLOC_SHIFT)
38
39#ifdef CONFIG_RANDOM_KMALLOC_CACHES
40# if defined(CONFIG_LOCKDEP) && !defined(CONFIG_PAGE_SIZE_4KB)
41# define PERCPU_DYNAMIC_SIZE_SHIFT 13
42# else
43# define PERCPU_DYNAMIC_SIZE_SHIFT 12
44#endif /* LOCKDEP and PAGE_SIZE > 4KiB */
45#else
46#define PERCPU_DYNAMIC_SIZE_SHIFT 10
47#endif
48
49/*
50 * Percpu allocator can serve percpu allocations before slab is
51 * initialized which allows slab to depend on the percpu allocator.
52 * The following parameter decide how much resource to preallocate
53 * for this. Keep PERCPU_DYNAMIC_RESERVE equal to or larger than
54 * PERCPU_DYNAMIC_EARLY_SIZE.
55 */
56#define PERCPU_DYNAMIC_EARLY_SIZE (20 << PERCPU_DYNAMIC_SIZE_SHIFT)
57
58/*
59 * PERCPU_DYNAMIC_RESERVE indicates the amount of free area to piggy
60 * back on the first chunk for dynamic percpu allocation if arch is
61 * manually allocating and mapping it for faster access (as a part of
62 * large page mapping for example).
63 *
64 * The following values give between one and two pages of free space
65 * after typical minimal boot (2-way SMP, single disk and NIC) with
66 * both defconfig and a distro config on x86_64 and 32. More
67 * intelligent way to determine this would be nice.
68 */
69#if BITS_PER_LONG > 32
70#define PERCPU_DYNAMIC_RESERVE (28 << PERCPU_DYNAMIC_SIZE_SHIFT)
71#else
72#define PERCPU_DYNAMIC_RESERVE (20 << PERCPU_DYNAMIC_SIZE_SHIFT)
73#endif
74
75extern void *pcpu_base_addr;
76extern const unsigned long *pcpu_unit_offsets;
77
78struct pcpu_group_info {
79 int nr_units; /* aligned # of units */
80 unsigned long base_offset; /* base address offset */
81 unsigned int *cpu_map; /* unit->cpu map, empty
82 * entries contain NR_CPUS */
83};
84
85struct pcpu_alloc_info {
86 size_t static_size;
87 size_t reserved_size;
88 size_t dyn_size;
89 size_t unit_size;
90 size_t atom_size;
91 size_t alloc_size;
92 size_t __ai_size; /* internal, don't use */
93 int nr_groups; /* 0 if grouping unnecessary */
94 struct pcpu_group_info groups[];
95};
96
97enum pcpu_fc {
98 PCPU_FC_AUTO,
99 PCPU_FC_EMBED,
100 PCPU_FC_PAGE,
101
102 PCPU_FC_NR,
103};
104extern const char * const pcpu_fc_names[PCPU_FC_NR];
105
106extern enum pcpu_fc pcpu_chosen_fc;
107
108typedef int (pcpu_fc_cpu_to_node_fn_t)(int cpu);
109typedef int (pcpu_fc_cpu_distance_fn_t)(unsigned int from, unsigned int to);
110
111extern struct pcpu_alloc_info * __init pcpu_alloc_alloc_info(int nr_groups,
112 int nr_units);
113extern void __init pcpu_free_alloc_info(struct pcpu_alloc_info *ai);
114
115extern void __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
116 void *base_addr);
117
118extern int __init pcpu_embed_first_chunk(size_t reserved_size, size_t dyn_size,
119 size_t atom_size,
120 pcpu_fc_cpu_distance_fn_t cpu_distance_fn,
121 pcpu_fc_cpu_to_node_fn_t cpu_to_nd_fn);
122
123#ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK
124void __init pcpu_populate_pte(unsigned long addr);
125extern int __init pcpu_page_first_chunk(size_t reserved_size,
126 pcpu_fc_cpu_to_node_fn_t cpu_to_nd_fn);
127#endif
128
129extern bool __is_kernel_percpu_address(unsigned long addr, unsigned long *can_addr);
130extern bool is_kernel_percpu_address(unsigned long addr);
131
132#if !defined(CONFIG_SMP) || !defined(CONFIG_HAVE_SETUP_PER_CPU_AREA)
133extern void __init setup_per_cpu_areas(void);
134#endif
135
136extern void __percpu *pcpu_alloc_noprof(size_t size, size_t align, bool reserved,
137 gfp_t gfp) __alloc_size(1);
138
139#define __alloc_percpu_gfp(_size, _align, _gfp) \
140 alloc_hooks(pcpu_alloc_noprof(_size, _align, false, _gfp))
141#define __alloc_percpu(_size, _align) \
142 alloc_hooks(pcpu_alloc_noprof(_size, _align, false, GFP_KERNEL))
143#define __alloc_reserved_percpu(_size, _align) \
144 alloc_hooks(pcpu_alloc_noprof(_size, _align, true, GFP_KERNEL))
145
146#define alloc_percpu_gfp(type, gfp) \
147 (typeof(type) __percpu *)__alloc_percpu_gfp(sizeof(type), \
148 __alignof__(type), gfp)
149#define alloc_percpu(type) \
150 (typeof(type) __percpu *)__alloc_percpu(sizeof(type), \
151 __alignof__(type))
152#define alloc_percpu_noprof(type) \
153 ((typeof(type) __percpu *)pcpu_alloc_noprof(sizeof(type), \
154 __alignof__(type), false, GFP_KERNEL))
155
156extern void free_percpu(void __percpu *__pdata);
157
158DEFINE_FREE(free_percpu, void __percpu *, free_percpu(_T))
159
160extern phys_addr_t per_cpu_ptr_to_phys(void *addr);
161
162extern unsigned long pcpu_nr_pages(void);
163
164#endif /* __LINUX_PERCPU_H */
165

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