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 71 extern void *pcpu_base_addr; 72 extern const unsigned long *pcpu_unit_offsets; 73 74 struct 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 81 struct 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 93 enum pcpu_fc { 94 PCPU_FC_AUTO, 95 PCPU_FC_EMBED, 96 PCPU_FC_PAGE, 97 98 PCPU_FC_NR, 99 }; 100 extern const char * const pcpu_fc_names[PCPU_FC_NR]; 101 102 extern enum pcpu_fc pcpu_chosen_fc; 103 104 typedef void * (*pcpu_fc_alloc_fn_t)(unsigned int cpu, size_t size, 105 size_t align); 106 typedef void (*pcpu_fc_free_fn_t)(void *ptr, size_t size); 107 typedef void (*pcpu_fc_populate_pte_fn_t)(unsigned long addr); 108 typedef int (pcpu_fc_cpu_distance_fn_t)(unsigned int from, unsigned int to); 109 110 extern struct pcpu_alloc_info * __init pcpu_alloc_alloc_info(int nr_groups, 111 int nr_units); 112 extern void __init pcpu_free_alloc_info(struct pcpu_alloc_info *ai); 113 114 extern 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 118 extern 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 126 extern 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 131 132 extern void __percpu *__alloc_reserved_percpu(size_t size, size_t align); 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 *__alloc_percpu_gfp(size_t size, size_t align, gfp_t gfp); 141 extern void __percpu *__alloc_percpu(size_t size, size_t align); 142 extern void free_percpu(void __percpu *__pdata); 143 extern 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)) 151 152 extern unsigned long pcpu_nr_pages(void); 153 154 #endif /* __LINUX_PERCPU_H */ 155