1 #ifndef __LINUX_PERCPU_H 2 #define __LINUX_PERCPU_H 3 4 #include <linux/preempt.h> 5 #include <linux/slab.h> /* For kmalloc() */ 6 #include <linux/smp.h> 7 #include <linux/cpumask.h> 8 #include <linux/pfn.h> 9 10 #include <asm/percpu.h> 11 12 /* enough to cover all DEFINE_PER_CPUs in modules */ 13 #ifdef CONFIG_MODULES 14 #define PERCPU_MODULE_RESERVE (8 << 10) 15 #else 16 #define PERCPU_MODULE_RESERVE 0 17 #endif 18 19 #ifndef PERCPU_ENOUGH_ROOM 20 #define PERCPU_ENOUGH_ROOM \ 21 (ALIGN(__per_cpu_end - __per_cpu_start, SMP_CACHE_BYTES) + \ 22 PERCPU_MODULE_RESERVE) 23 #endif 24 25 /* 26 * Must be an lvalue. Since @var must be a simple identifier, 27 * we force a syntax error here if it isn't. 28 */ 29 #define get_cpu_var(var) (*({ \ 30 extern int simple_identifier_##var(void); \ 31 preempt_disable(); \ 32 &__get_cpu_var(var); })) 33 #define put_cpu_var(var) preempt_enable() 34 35 #ifdef CONFIG_SMP 36 37 #ifndef CONFIG_HAVE_LEGACY_PER_CPU_AREA 38 39 /* minimum unit size, also is the maximum supported allocation size */ 40 #define PCPU_MIN_UNIT_SIZE PFN_ALIGN(64 << 10) 41 42 /* 43 * PERCPU_DYNAMIC_RESERVE indicates the amount of free area to piggy 44 * back on the first chunk for dynamic percpu allocation if arch is 45 * manually allocating and mapping it for faster access (as a part of 46 * large page mapping for example). 47 * 48 * The following values give between one and two pages of free space 49 * after typical minimal boot (2-way SMP, single disk and NIC) with 50 * both defconfig and a distro config on x86_64 and 32. More 51 * intelligent way to determine this would be nice. 52 */ 53 #if BITS_PER_LONG > 32 54 #define PERCPU_DYNAMIC_RESERVE (20 << 10) 55 #else 56 #define PERCPU_DYNAMIC_RESERVE (12 << 10) 57 #endif 58 59 extern void *pcpu_base_addr; 60 extern const unsigned long *pcpu_unit_offsets; 61 62 struct pcpu_group_info { 63 int nr_units; /* aligned # of units */ 64 unsigned long base_offset; /* base address offset */ 65 unsigned int *cpu_map; /* unit->cpu map, empty 66 * entries contain NR_CPUS */ 67 }; 68 69 struct pcpu_alloc_info { 70 size_t static_size; 71 size_t reserved_size; 72 size_t dyn_size; 73 size_t unit_size; 74 size_t atom_size; 75 size_t alloc_size; 76 size_t __ai_size; /* internal, don't use */ 77 int nr_groups; /* 0 if grouping unnecessary */ 78 struct pcpu_group_info groups[]; 79 }; 80 81 enum pcpu_fc { 82 PCPU_FC_AUTO, 83 PCPU_FC_EMBED, 84 PCPU_FC_PAGE, 85 86 PCPU_FC_NR, 87 }; 88 extern const char *pcpu_fc_names[PCPU_FC_NR]; 89 90 extern enum pcpu_fc pcpu_chosen_fc; 91 92 typedef void * (*pcpu_fc_alloc_fn_t)(unsigned int cpu, size_t size, 93 size_t align); 94 typedef void (*pcpu_fc_free_fn_t)(void *ptr, size_t size); 95 typedef void (*pcpu_fc_populate_pte_fn_t)(unsigned long addr); 96 typedef int (pcpu_fc_cpu_distance_fn_t)(unsigned int from, unsigned int to); 97 98 extern struct pcpu_alloc_info * __init pcpu_alloc_alloc_info(int nr_groups, 99 int nr_units); 100 extern void __init pcpu_free_alloc_info(struct pcpu_alloc_info *ai); 101 102 extern struct pcpu_alloc_info * __init pcpu_build_alloc_info( 103 size_t reserved_size, ssize_t dyn_size, 104 size_t atom_size, 105 pcpu_fc_cpu_distance_fn_t cpu_distance_fn); 106 107 extern int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai, 108 void *base_addr); 109 110 #ifdef CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK 111 extern int __init pcpu_embed_first_chunk(size_t reserved_size, ssize_t dyn_size, 112 size_t atom_size, 113 pcpu_fc_cpu_distance_fn_t cpu_distance_fn, 114 pcpu_fc_alloc_fn_t alloc_fn, 115 pcpu_fc_free_fn_t free_fn); 116 #endif 117 118 #ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK 119 extern int __init pcpu_page_first_chunk(size_t reserved_size, 120 pcpu_fc_alloc_fn_t alloc_fn, 121 pcpu_fc_free_fn_t free_fn, 122 pcpu_fc_populate_pte_fn_t populate_pte_fn); 123 #endif 124 125 /* 126 * Use this to get to a cpu's version of the per-cpu object 127 * dynamically allocated. Non-atomic access to the current CPU's 128 * version should probably be combined with get_cpu()/put_cpu(). 129 */ 130 #define per_cpu_ptr(ptr, cpu) SHIFT_PERCPU_PTR((ptr), per_cpu_offset((cpu))) 131 132 extern void *__alloc_reserved_percpu(size_t size, size_t align); 133 134 #else /* CONFIG_HAVE_LEGACY_PER_CPU_AREA */ 135 136 struct percpu_data { 137 void *ptrs[1]; 138 }; 139 140 /* pointer disguising messes up the kmemleak objects tracking */ 141 #ifndef CONFIG_DEBUG_KMEMLEAK 142 #define __percpu_disguise(pdata) (struct percpu_data *)~(unsigned long)(pdata) 143 #else 144 #define __percpu_disguise(pdata) (struct percpu_data *)(pdata) 145 #endif 146 147 #define per_cpu_ptr(ptr, cpu) \ 148 ({ \ 149 struct percpu_data *__p = __percpu_disguise(ptr); \ 150 (__typeof__(ptr))__p->ptrs[(cpu)]; \ 151 }) 152 153 #endif /* CONFIG_HAVE_LEGACY_PER_CPU_AREA */ 154 155 extern void *__alloc_percpu(size_t size, size_t align); 156 extern void free_percpu(void *__pdata); 157 158 #ifndef CONFIG_HAVE_SETUP_PER_CPU_AREA 159 extern void __init setup_per_cpu_areas(void); 160 #endif 161 162 #else /* CONFIG_SMP */ 163 164 #define per_cpu_ptr(ptr, cpu) ({ (void)(cpu); (ptr); }) 165 166 static inline void *__alloc_percpu(size_t size, size_t align) 167 { 168 /* 169 * Can't easily make larger alignment work with kmalloc. WARN 170 * on it. Larger alignment should only be used for module 171 * percpu sections on SMP for which this path isn't used. 172 */ 173 WARN_ON_ONCE(align > SMP_CACHE_BYTES); 174 return kzalloc(size, GFP_KERNEL); 175 } 176 177 static inline void free_percpu(void *p) 178 { 179 kfree(p); 180 } 181 182 static inline void __init setup_per_cpu_areas(void) { } 183 184 static inline void *pcpu_lpage_remapped(void *kaddr) 185 { 186 return NULL; 187 } 188 189 #endif /* CONFIG_SMP */ 190 191 #define alloc_percpu(type) (type *)__alloc_percpu(sizeof(type), \ 192 __alignof__(type)) 193 194 /* 195 * Optional methods for optimized non-lvalue per-cpu variable access. 196 * 197 * @var can be a percpu variable or a field of it and its size should 198 * equal char, int or long. percpu_read() evaluates to a lvalue and 199 * all others to void. 200 * 201 * These operations are guaranteed to be atomic w.r.t. preemption. 202 * The generic versions use plain get/put_cpu_var(). Archs are 203 * encouraged to implement single-instruction alternatives which don't 204 * require preemption protection. 205 */ 206 #ifndef percpu_read 207 # define percpu_read(var) \ 208 ({ \ 209 typeof(per_cpu_var(var)) __tmp_var__; \ 210 __tmp_var__ = get_cpu_var(var); \ 211 put_cpu_var(var); \ 212 __tmp_var__; \ 213 }) 214 #endif 215 216 #define __percpu_generic_to_op(var, val, op) \ 217 do { \ 218 get_cpu_var(var) op val; \ 219 put_cpu_var(var); \ 220 } while (0) 221 222 #ifndef percpu_write 223 # define percpu_write(var, val) __percpu_generic_to_op(var, (val), =) 224 #endif 225 226 #ifndef percpu_add 227 # define percpu_add(var, val) __percpu_generic_to_op(var, (val), +=) 228 #endif 229 230 #ifndef percpu_sub 231 # define percpu_sub(var, val) __percpu_generic_to_op(var, (val), -=) 232 #endif 233 234 #ifndef percpu_and 235 # define percpu_and(var, val) __percpu_generic_to_op(var, (val), &=) 236 #endif 237 238 #ifndef percpu_or 239 # define percpu_or(var, val) __percpu_generic_to_op(var, (val), |=) 240 #endif 241 242 #ifndef percpu_xor 243 # define percpu_xor(var, val) __percpu_generic_to_op(var, (val), ^=) 244 #endif 245 246 #endif /* __LINUX_PERCPU_H */ 247