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  #ifdef CONFIG_MEM_ALLOC_PROFILING
19  #define PERCPU_MODULE_RESERVE		(8 << 13)
20  #else
21  #define PERCPU_MODULE_RESERVE		(8 << 10)
22  #endif
23  #else
24  #define PERCPU_MODULE_RESERVE		0
25  #endif
26  
27  /* minimum unit size, also is the maximum supported allocation size */
28  #define PCPU_MIN_UNIT_SIZE		PFN_ALIGN(32 << 10)
29  
30  /* minimum allocation size and shift in bytes */
31  #define PCPU_MIN_ALLOC_SHIFT		2
32  #define PCPU_MIN_ALLOC_SIZE		(1 << PCPU_MIN_ALLOC_SHIFT)
33  
34  /*
35   * The PCPU_BITMAP_BLOCK_SIZE must be the same size as PAGE_SIZE as the
36   * updating of hints is used to manage the nr_empty_pop_pages in both
37   * the chunk and globally.
38   */
39  #define PCPU_BITMAP_BLOCK_SIZE		PAGE_SIZE
40  #define PCPU_BITMAP_BLOCK_BITS		(PCPU_BITMAP_BLOCK_SIZE >>	\
41  					 PCPU_MIN_ALLOC_SHIFT)
42  
43  #ifdef CONFIG_RANDOM_KMALLOC_CACHES
44  # if defined(CONFIG_LOCKDEP) && !defined(CONFIG_PAGE_SIZE_4KB)
45  # define PERCPU_DYNAMIC_SIZE_SHIFT      13
46  # else
47  # define PERCPU_DYNAMIC_SIZE_SHIFT      12
48  #endif /* LOCKDEP and PAGE_SIZE > 4KiB */
49  #else
50  #define PERCPU_DYNAMIC_SIZE_SHIFT      10
51  #endif
52  
53  /*
54   * Percpu allocator can serve percpu allocations before slab is
55   * initialized which allows slab to depend on the percpu allocator.
56   * The following parameter decide how much resource to preallocate
57   * for this.  Keep PERCPU_DYNAMIC_RESERVE equal to or larger than
58   * PERCPU_DYNAMIC_EARLY_SIZE.
59   */
60  #define PERCPU_DYNAMIC_EARLY_SIZE	(20 << PERCPU_DYNAMIC_SIZE_SHIFT)
61  
62  /*
63   * PERCPU_DYNAMIC_RESERVE indicates the amount of free area to piggy
64   * back on the first chunk for dynamic percpu allocation if arch is
65   * manually allocating and mapping it for faster access (as a part of
66   * large page mapping for example).
67   *
68   * The following values give between one and two pages of free space
69   * after typical minimal boot (2-way SMP, single disk and NIC) with
70   * both defconfig and a distro config on x86_64 and 32.  More
71   * intelligent way to determine this would be nice.
72   */
73  #if BITS_PER_LONG > 32
74  #define PERCPU_DYNAMIC_RESERVE		(28 << PERCPU_DYNAMIC_SIZE_SHIFT)
75  #else
76  #define PERCPU_DYNAMIC_RESERVE		(20 << PERCPU_DYNAMIC_SIZE_SHIFT)
77  #endif
78  
79  extern void *pcpu_base_addr;
80  extern const unsigned long *pcpu_unit_offsets;
81  
82  struct pcpu_group_info {
83  	int			nr_units;	/* aligned # of units */
84  	unsigned long		base_offset;	/* base address offset */
85  	unsigned int		*cpu_map;	/* unit->cpu map, empty
86  						 * entries contain NR_CPUS */
87  };
88  
89  struct pcpu_alloc_info {
90  	size_t			static_size;
91  	size_t			reserved_size;
92  	size_t			dyn_size;
93  	size_t			unit_size;
94  	size_t			atom_size;
95  	size_t			alloc_size;
96  	size_t			__ai_size;	/* internal, don't use */
97  	int			nr_groups;	/* 0 if grouping unnecessary */
98  	struct pcpu_group_info	groups[];
99  };
100  
101  enum pcpu_fc {
102  	PCPU_FC_AUTO,
103  	PCPU_FC_EMBED,
104  	PCPU_FC_PAGE,
105  
106  	PCPU_FC_NR,
107  };
108  extern const char * const pcpu_fc_names[PCPU_FC_NR];
109  
110  extern enum pcpu_fc pcpu_chosen_fc;
111  
112  typedef int (pcpu_fc_cpu_to_node_fn_t)(int cpu);
113  typedef int (pcpu_fc_cpu_distance_fn_t)(unsigned int from, unsigned int to);
114  
115  extern struct pcpu_alloc_info * __init pcpu_alloc_alloc_info(int nr_groups,
116  							     int nr_units);
117  extern void __init pcpu_free_alloc_info(struct pcpu_alloc_info *ai);
118  
119  extern void __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
120  					 void *base_addr);
121  
122  extern int __init pcpu_embed_first_chunk(size_t reserved_size, size_t dyn_size,
123  				size_t atom_size,
124  				pcpu_fc_cpu_distance_fn_t cpu_distance_fn,
125  				pcpu_fc_cpu_to_node_fn_t cpu_to_nd_fn);
126  
127  #ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK
128  void __init pcpu_populate_pte(unsigned long addr);
129  extern int __init pcpu_page_first_chunk(size_t reserved_size,
130  				pcpu_fc_cpu_to_node_fn_t cpu_to_nd_fn);
131  #endif
132  
133  extern bool __is_kernel_percpu_address(unsigned long addr, unsigned long *can_addr);
134  extern bool is_kernel_percpu_address(unsigned long addr);
135  
136  #if !defined(CONFIG_SMP) || !defined(CONFIG_HAVE_SETUP_PER_CPU_AREA)
137  extern void __init setup_per_cpu_areas(void);
138  #endif
139  
140  extern void __percpu *pcpu_alloc_noprof(size_t size, size_t align, bool reserved,
141  				   gfp_t gfp) __alloc_size(1);
142  
143  #define __alloc_percpu_gfp(_size, _align, _gfp)				\
144  	alloc_hooks(pcpu_alloc_noprof(_size, _align, false, _gfp))
145  #define __alloc_percpu(_size, _align)					\
146  	alloc_hooks(pcpu_alloc_noprof(_size, _align, false, GFP_KERNEL))
147  #define __alloc_reserved_percpu(_size, _align)				\
148  	alloc_hooks(pcpu_alloc_noprof(_size, _align, true, GFP_KERNEL))
149  
150  #define alloc_percpu_gfp(type, gfp)					\
151  	(typeof(type) __percpu *)__alloc_percpu_gfp(sizeof(type),	\
152  						__alignof__(type), gfp)
153  #define alloc_percpu(type)						\
154  	(typeof(type) __percpu *)__alloc_percpu(sizeof(type),		\
155  						__alignof__(type))
156  #define alloc_percpu_noprof(type)					\
157  	((typeof(type) __percpu *)pcpu_alloc_noprof(sizeof(type),	\
158  					__alignof__(type), false, GFP_KERNEL))
159  
160  extern void free_percpu(void __percpu *__pdata);
161  
162  DEFINE_FREE(free_percpu, void __percpu *, free_percpu(_T))
163  
164  extern phys_addr_t per_cpu_ptr_to_phys(void *addr);
165  
166  extern unsigned long pcpu_nr_pages(void);
167  
168  #endif /* __LINUX_PERCPU_H */
169