1 #ifndef _ASM_GENERIC_PERCPU_H_ 2 #define _ASM_GENERIC_PERCPU_H_ 3 #include <linux/compiler.h> 4 #include <linux/threads.h> 5 6 /* 7 * Determine the real variable name from the name visible in the 8 * kernel sources. 9 */ 10 #define per_cpu_var(var) per_cpu__##var 11 12 #ifdef CONFIG_SMP 13 14 /* 15 * per_cpu_offset() is the offset that has to be added to a 16 * percpu variable to get to the instance for a certain processor. 17 * 18 * Most arches use the __per_cpu_offset array for those offsets but 19 * some arches have their own ways of determining the offset (x86_64, s390). 20 */ 21 #ifndef __per_cpu_offset 22 extern unsigned long __per_cpu_offset[NR_CPUS]; 23 24 #define per_cpu_offset(x) (__per_cpu_offset[x]) 25 #endif 26 27 /* 28 * Determine the offset for the currently active processor. 29 * An arch may define __my_cpu_offset to provide a more effective 30 * means of obtaining the offset to the per cpu variables of the 31 * current processor. 32 */ 33 #ifndef __my_cpu_offset 34 #define __my_cpu_offset per_cpu_offset(raw_smp_processor_id()) 35 #define my_cpu_offset per_cpu_offset(smp_processor_id()) 36 #else 37 #define my_cpu_offset __my_cpu_offset 38 #endif 39 40 /* 41 * Add a offset to a pointer but keep the pointer as is. 42 * 43 * Only S390 provides its own means of moving the pointer. 44 */ 45 #ifndef SHIFT_PERCPU_PTR 46 #define SHIFT_PERCPU_PTR(__p, __offset) RELOC_HIDE((__p), (__offset)) 47 #endif 48 49 /* 50 * A percpu variable may point to a discarded regions. The following are 51 * established ways to produce a usable pointer from the percpu variable 52 * offset. 53 */ 54 #define per_cpu(var, cpu) \ 55 (*SHIFT_PERCPU_PTR(&per_cpu_var(var), per_cpu_offset(cpu))) 56 #define __get_cpu_var(var) \ 57 (*SHIFT_PERCPU_PTR(&per_cpu_var(var), my_cpu_offset)) 58 #define __raw_get_cpu_var(var) \ 59 (*SHIFT_PERCPU_PTR(&per_cpu_var(var), __my_cpu_offset)) 60 61 62 #ifdef CONFIG_HAVE_SETUP_PER_CPU_AREA 63 extern void setup_per_cpu_areas(void); 64 #endif 65 66 #else /* ! SMP */ 67 68 #define per_cpu(var, cpu) (*((void)(cpu), &per_cpu_var(var))) 69 #define __get_cpu_var(var) per_cpu_var(var) 70 #define __raw_get_cpu_var(var) per_cpu_var(var) 71 72 #endif /* SMP */ 73 74 #ifndef PER_CPU_ATTRIBUTES 75 #define PER_CPU_ATTRIBUTES 76 #endif 77 78 #define DECLARE_PER_CPU(type, name) extern PER_CPU_ATTRIBUTES \ 79 __typeof__(type) per_cpu_var(name) 80 81 #endif /* _ASM_GENERIC_PERCPU_H_ */ 82