xref: /openbmc/linux/include/linux/percpu.h (revision 3c615294)
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 
70 extern void *pcpu_base_addr;
71 extern const unsigned long *pcpu_unit_offsets;
72 
73 struct 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 
80 struct 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 
92 enum pcpu_fc {
93 	PCPU_FC_AUTO,
94 	PCPU_FC_EMBED,
95 	PCPU_FC_PAGE,
96 
97 	PCPU_FC_NR,
98 };
99 extern const char * const pcpu_fc_names[PCPU_FC_NR];
100 
101 extern enum pcpu_fc pcpu_chosen_fc;
102 
103 typedef int (pcpu_fc_cpu_to_node_fn_t)(int cpu);
104 typedef int (pcpu_fc_cpu_distance_fn_t)(unsigned int from, unsigned int to);
105 
106 extern struct pcpu_alloc_info * __init pcpu_alloc_alloc_info(int nr_groups,
107 							     int nr_units);
108 extern void __init pcpu_free_alloc_info(struct pcpu_alloc_info *ai);
109 
110 extern void __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
111 					 void *base_addr);
112 
113 extern 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
119 void __init pcpu_populate_pte(unsigned long addr);
120 extern 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 
124 extern void __percpu *__alloc_reserved_percpu(size_t size, size_t align) __alloc_size(1);
125 extern bool __is_kernel_percpu_address(unsigned long addr, unsigned long *can_addr);
126 extern bool is_kernel_percpu_address(unsigned long addr);
127 
128 #if !defined(CONFIG_SMP) || !defined(CONFIG_HAVE_SETUP_PER_CPU_AREA)
129 extern void __init setup_per_cpu_areas(void);
130 #endif
131 
132 extern void __percpu *__alloc_percpu_gfp(size_t size, size_t align, gfp_t gfp) __alloc_size(1);
133 extern void __percpu *__alloc_percpu(size_t size, size_t align) __alloc_size(1);
134 extern void free_percpu(void __percpu *__pdata);
135 
136 DEFINE_FREE(free_percpu, void __percpu *, free_percpu(_T))
137 
138 extern phys_addr_t per_cpu_ptr_to_phys(void *addr);
139 
140 #define alloc_percpu_gfp(type, gfp)					\
141 	(typeof(type) __percpu *)__alloc_percpu_gfp(sizeof(type),	\
142 						__alignof__(type), gfp)
143 #define alloc_percpu(type)						\
144 	(typeof(type) __percpu *)__alloc_percpu(sizeof(type),		\
145 						__alignof__(type))
146 
147 extern unsigned long pcpu_nr_pages(void);
148 
149 #endif /* __LINUX_PERCPU_H */
150