1 #ifndef _ASM_GENERIC_PERCPU_H_ 2 #define _ASM_GENERIC_PERCPU_H_ 3 4 #include <linux/compiler.h> 5 #include <linux/threads.h> 6 #include <linux/percpu-defs.h> 7 8 #ifdef CONFIG_SMP 9 10 /* 11 * per_cpu_offset() is the offset that has to be added to a 12 * percpu variable to get to the instance for a certain processor. 13 * 14 * Most arches use the __per_cpu_offset array for those offsets but 15 * some arches have their own ways of determining the offset (x86_64, s390). 16 */ 17 #ifndef __per_cpu_offset 18 extern unsigned long __per_cpu_offset[NR_CPUS]; 19 20 #define per_cpu_offset(x) (__per_cpu_offset[x]) 21 #endif 22 23 /* 24 * Determine the offset for the currently active processor. 25 * An arch may define __my_cpu_offset to provide a more effective 26 * means of obtaining the offset to the per cpu variables of the 27 * current processor. 28 */ 29 #ifndef __my_cpu_offset 30 #define __my_cpu_offset per_cpu_offset(raw_smp_processor_id()) 31 #endif 32 #ifdef CONFIG_DEBUG_PREEMPT 33 #define my_cpu_offset per_cpu_offset(smp_processor_id()) 34 #else 35 #define my_cpu_offset __my_cpu_offset 36 #endif 37 38 /* 39 * Add a offset to a pointer but keep the pointer as is. 40 * 41 * Only S390 provides its own means of moving the pointer. 42 */ 43 #ifndef SHIFT_PERCPU_PTR 44 #define SHIFT_PERCPU_PTR(__p, __offset) RELOC_HIDE((__p), (__offset)) 45 #endif 46 47 /* 48 * A percpu variable may point to a discarded regions. The following are 49 * established ways to produce a usable pointer from the percpu variable 50 * offset. 51 */ 52 #define per_cpu(var, cpu) \ 53 (*SHIFT_PERCPU_PTR(&per_cpu_var(var), per_cpu_offset(cpu))) 54 #define __get_cpu_var(var) \ 55 (*SHIFT_PERCPU_PTR(&per_cpu_var(var), my_cpu_offset)) 56 #define __raw_get_cpu_var(var) \ 57 (*SHIFT_PERCPU_PTR(&per_cpu_var(var), __my_cpu_offset)) 58 59 60 #ifdef CONFIG_HAVE_SETUP_PER_CPU_AREA 61 extern void setup_per_cpu_areas(void); 62 #endif 63 64 #else /* ! SMP */ 65 66 #define per_cpu(var, cpu) (*((void)(cpu), &per_cpu_var(var))) 67 #define __get_cpu_var(var) per_cpu_var(var) 68 #define __raw_get_cpu_var(var) per_cpu_var(var) 69 70 #endif /* SMP */ 71 72 #ifndef PER_CPU_BASE_SECTION 73 #ifdef CONFIG_SMP 74 #define PER_CPU_BASE_SECTION ".data.percpu" 75 #else 76 #define PER_CPU_BASE_SECTION ".data" 77 #endif 78 #endif 79 80 #ifdef CONFIG_SMP 81 82 #ifdef MODULE 83 #define PER_CPU_SHARED_ALIGNED_SECTION "" 84 #else 85 #define PER_CPU_SHARED_ALIGNED_SECTION ".shared_aligned" 86 #endif 87 #define PER_CPU_FIRST_SECTION ".first" 88 89 #else 90 91 #define PER_CPU_SHARED_ALIGNED_SECTION "" 92 #define PER_CPU_FIRST_SECTION "" 93 94 #endif 95 96 #ifndef PER_CPU_ATTRIBUTES 97 #define PER_CPU_ATTRIBUTES 98 #endif 99 100 #endif /* _ASM_GENERIC_PERCPU_H_ */ 101