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/printk.h>
10#include <linux/pfn.h>
11#include <linux/init.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/* number of bits per page, used to trigger a scan if blocks are > PAGE_SIZE */
30#define PCPU_BITS_PER_PAGE (PAGE_SIZE >> PCPU_MIN_ALLOC_SHIFT)
31
32/*
33 * This determines the size of each metadata block. There are several subtle
34 * constraints around this constant. The reserved region must be a multiple of
35 * PCPU_BITMAP_BLOCK_SIZE. Additionally, PCPU_BITMAP_BLOCK_SIZE must be a
36 * multiple of PAGE_SIZE or PAGE_SIZE must be a multiple of
37 * PCPU_BITMAP_BLOCK_SIZE to align with the populated page map. The unit_size
38 * also has to be a multiple of PCPU_BITMAP_BLOCK_SIZE to ensure full blocks.
39 */
40#define PCPU_BITMAP_BLOCK_SIZE PAGE_SIZE
41#define PCPU_BITMAP_BLOCK_BITS (PCPU_BITMAP_BLOCK_SIZE >> \
42 PCPU_MIN_ALLOC_SHIFT)
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 two parameters decide how much resource to
48 * preallocate for this. Keep PERCPU_DYNAMIC_RESERVE equal to or
49 * larger than PERCPU_DYNAMIC_EARLY_SIZE.
50 */
51#define PERCPU_DYNAMIC_EARLY_SLOTS 128
52#define PERCPU_DYNAMIC_EARLY_SIZE (12 << 10)
53
54/*
55 * PERCPU_DYNAMIC_RESERVE indicates the amount of free area to piggy
56 * back on the first chunk for dynamic percpu allocation if arch is
57 * manually allocating and mapping it for faster access (as a part of
58 * large page mapping for example).
59 *
60 * The following values give between one and two pages of free space
61 * after typical minimal boot (2-way SMP, single disk and NIC) with
62 * both defconfig and a distro config on x86_64 and 32. More
63 * intelligent way to determine this would be nice.
64 */
65#if BITS_PER_LONG > 32
66#define PERCPU_DYNAMIC_RESERVE (28 << 10)
67#else
68#define PERCPU_DYNAMIC_RESERVE (20 << 10)
69#endif
70
71extern void *pcpu_base_addr;
72extern const unsigned long *pcpu_unit_offsets;
73
74struct pcpu_group_info {
75 int nr_units; /* aligned # of units */
76 unsigned long base_offset; /* base address offset */
77 unsigned int *cpu_map; /* unit->cpu map, empty
78 * entries contain NR_CPUS */
79};
80
81struct pcpu_alloc_info {
82 size_t static_size;
83 size_t reserved_size;
84 size_t dyn_size;
85 size_t unit_size;
86 size_t atom_size;
87 size_t alloc_size;
88 size_t __ai_size; /* internal, don't use */
89 int nr_groups; /* 0 if grouping unnecessary */
90 struct pcpu_group_info groups[];
91};
92
93enum pcpu_fc {
94 PCPU_FC_AUTO,
95 PCPU_FC_EMBED,
96 PCPU_FC_PAGE,
97
98 PCPU_FC_NR,
99};
100extern const char * const pcpu_fc_names[PCPU_FC_NR];
101
102extern enum pcpu_fc pcpu_chosen_fc;
103
104typedef void * (*pcpu_fc_alloc_fn_t)(unsigned int cpu, size_t size,
105 size_t align);
106typedef void (*pcpu_fc_free_fn_t)(void *ptr, size_t size);
107typedef void (*pcpu_fc_populate_pte_fn_t)(unsigned long addr);
108typedef int (pcpu_fc_cpu_distance_fn_t)(unsigned int from, unsigned int to);
109
110extern struct pcpu_alloc_info * __init pcpu_alloc_alloc_info(int nr_groups,
111 int nr_units);
112extern void __init pcpu_free_alloc_info(struct pcpu_alloc_info *ai);
113
114extern int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
115 void *base_addr);
116
117#ifdef CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK
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_alloc_fn_t alloc_fn,
122 pcpu_fc_free_fn_t free_fn);
123#endif
124
125#ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK
126extern int __init pcpu_page_first_chunk(size_t reserved_size,
127 pcpu_fc_alloc_fn_t alloc_fn,
128 pcpu_fc_free_fn_t free_fn,
129 pcpu_fc_populate_pte_fn_t populate_pte_fn);
130#endif
131
132extern void __percpu *__alloc_reserved_percpu(size_t size, size_t align);
133extern bool __is_kernel_percpu_address(unsigned long addr, unsigned long *can_addr);
134extern bool is_kernel_percpu_address(unsigned long addr);
135
136#if !defined(CONFIG_SMP) || !defined(CONFIG_HAVE_SETUP_PER_CPU_AREA)
137extern void __init setup_per_cpu_areas(void);
138#endif
139
140extern void __percpu *__alloc_percpu_gfp(size_t size, size_t align, gfp_t gfp);
141extern void __percpu *__alloc_percpu(size_t size, size_t align);
142extern void free_percpu(void __percpu *__pdata);
143extern phys_addr_t per_cpu_ptr_to_phys(void *addr);
144
145#define alloc_percpu_gfp(type, gfp) \
146 (typeof(type) __percpu *)__alloc_percpu_gfp(sizeof(type), \
147 __alignof__(type), gfp)
148#define alloc_percpu(type) \
149 (typeof(type) __percpu *)__alloc_percpu(sizeof(type), \
150 __alignof__(type))
151
152extern unsigned long pcpu_nr_pages(void);
153
154#endif /* __LINUX_PERCPU_H */
155