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 #ifdef CONFIG_HAVE_DYNAMIC_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 61 typedef struct page * (*pcpu_get_page_fn_t)(unsigned int cpu, int pageno); 62 typedef void (*pcpu_populate_pte_fn_t)(unsigned long addr); 63 64 extern size_t __init pcpu_setup_first_chunk(pcpu_get_page_fn_t get_page_fn, 65 size_t static_size, size_t reserved_size, 66 ssize_t dyn_size, ssize_t unit_size, 67 void *base_addr, 68 pcpu_populate_pte_fn_t populate_pte_fn); 69 70 extern ssize_t __init pcpu_embed_first_chunk( 71 size_t static_size, size_t reserved_size, 72 ssize_t dyn_size, ssize_t unit_size); 73 74 /* 75 * Use this to get to a cpu's version of the per-cpu object 76 * dynamically allocated. Non-atomic access to the current CPU's 77 * version should probably be combined with get_cpu()/put_cpu(). 78 */ 79 #define per_cpu_ptr(ptr, cpu) SHIFT_PERCPU_PTR((ptr), per_cpu_offset((cpu))) 80 81 extern void *__alloc_reserved_percpu(size_t size, size_t align); 82 83 #else /* CONFIG_HAVE_DYNAMIC_PER_CPU_AREA */ 84 85 struct percpu_data { 86 void *ptrs[1]; 87 }; 88 89 #define __percpu_disguise(pdata) (struct percpu_data *)~(unsigned long)(pdata) 90 91 #define per_cpu_ptr(ptr, cpu) \ 92 ({ \ 93 struct percpu_data *__p = __percpu_disguise(ptr); \ 94 (__typeof__(ptr))__p->ptrs[(cpu)]; \ 95 }) 96 97 #endif /* CONFIG_HAVE_DYNAMIC_PER_CPU_AREA */ 98 99 extern void *__alloc_percpu(size_t size, size_t align); 100 extern void free_percpu(void *__pdata); 101 102 #else /* CONFIG_SMP */ 103 104 #define per_cpu_ptr(ptr, cpu) ({ (void)(cpu); (ptr); }) 105 106 static inline void *__alloc_percpu(size_t size, size_t align) 107 { 108 /* 109 * Can't easily make larger alignment work with kmalloc. WARN 110 * on it. Larger alignment should only be used for module 111 * percpu sections on SMP for which this path isn't used. 112 */ 113 WARN_ON_ONCE(align > SMP_CACHE_BYTES); 114 return kzalloc(size, GFP_KERNEL); 115 } 116 117 static inline void free_percpu(void *p) 118 { 119 kfree(p); 120 } 121 122 #endif /* CONFIG_SMP */ 123 124 #define alloc_percpu(type) (type *)__alloc_percpu(sizeof(type), \ 125 __alignof__(type)) 126 127 /* 128 * Optional methods for optimized non-lvalue per-cpu variable access. 129 * 130 * @var can be a percpu variable or a field of it and its size should 131 * equal char, int or long. percpu_read() evaluates to a lvalue and 132 * all others to void. 133 * 134 * These operations are guaranteed to be atomic w.r.t. preemption. 135 * The generic versions use plain get/put_cpu_var(). Archs are 136 * encouraged to implement single-instruction alternatives which don't 137 * require preemption protection. 138 */ 139 #ifndef percpu_read 140 # define percpu_read(var) \ 141 ({ \ 142 typeof(per_cpu_var(var)) __tmp_var__; \ 143 __tmp_var__ = get_cpu_var(var); \ 144 put_cpu_var(var); \ 145 __tmp_var__; \ 146 }) 147 #endif 148 149 #define __percpu_generic_to_op(var, val, op) \ 150 do { \ 151 get_cpu_var(var) op val; \ 152 put_cpu_var(var); \ 153 } while (0) 154 155 #ifndef percpu_write 156 # define percpu_write(var, val) __percpu_generic_to_op(var, (val), =) 157 #endif 158 159 #ifndef percpu_add 160 # define percpu_add(var, val) __percpu_generic_to_op(var, (val), +=) 161 #endif 162 163 #ifndef percpu_sub 164 # define percpu_sub(var, val) __percpu_generic_to_op(var, (val), -=) 165 #endif 166 167 #ifndef percpu_and 168 # define percpu_and(var, val) __percpu_generic_to_op(var, (val), &=) 169 #endif 170 171 #ifndef percpu_or 172 # define percpu_or(var, val) __percpu_generic_to_op(var, (val), |=) 173 #endif 174 175 #ifndef percpu_xor 176 # define percpu_xor(var, val) __percpu_generic_to_op(var, (val), ^=) 177 #endif 178 179 #endif /* __LINUX_PERCPU_H */ 180