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 /* Weird cast keeps both GCC and sparse happy. */ 45 #define SHIFT_PERCPU_PTR(__p, __offset) ({ \ 46 __verify_pcpu_ptr((__p)); \ 47 RELOC_HIDE((typeof(*(__p)) __kernel __force *)(__p), (__offset)); \ 48 }) 49 #endif 50 51 /* 52 * A percpu variable may point to a discarded regions. The following are 53 * established ways to produce a usable pointer from the percpu variable 54 * offset. 55 */ 56 #define per_cpu(var, cpu) \ 57 (*SHIFT_PERCPU_PTR(&(var), per_cpu_offset(cpu))) 58 #define __get_cpu_var(var) \ 59 (*SHIFT_PERCPU_PTR(&(var), my_cpu_offset)) 60 #define __raw_get_cpu_var(var) \ 61 (*SHIFT_PERCPU_PTR(&(var), __my_cpu_offset)) 62 63 #define this_cpu_ptr(ptr) SHIFT_PERCPU_PTR(ptr, my_cpu_offset) 64 #define __this_cpu_ptr(ptr) SHIFT_PERCPU_PTR(ptr, __my_cpu_offset) 65 66 67 #ifdef CONFIG_HAVE_SETUP_PER_CPU_AREA 68 extern void setup_per_cpu_areas(void); 69 #endif 70 71 #else /* ! SMP */ 72 73 #define per_cpu(var, cpu) (*((void)(cpu), &(var))) 74 #define __get_cpu_var(var) (var) 75 #define __raw_get_cpu_var(var) (var) 76 #define this_cpu_ptr(ptr) per_cpu_ptr(ptr, 0) 77 #define __this_cpu_ptr(ptr) this_cpu_ptr(ptr) 78 79 #endif /* SMP */ 80 81 #ifndef PER_CPU_BASE_SECTION 82 #ifdef CONFIG_SMP 83 #define PER_CPU_BASE_SECTION ".data..percpu" 84 #else 85 #define PER_CPU_BASE_SECTION ".data" 86 #endif 87 #endif 88 89 #ifdef CONFIG_SMP 90 91 #ifdef MODULE 92 #define PER_CPU_SHARED_ALIGNED_SECTION "" 93 #define PER_CPU_ALIGNED_SECTION "" 94 #else 95 #define PER_CPU_SHARED_ALIGNED_SECTION "..shared_aligned" 96 #define PER_CPU_ALIGNED_SECTION "..shared_aligned" 97 #endif 98 #define PER_CPU_FIRST_SECTION "..first" 99 100 #else 101 102 #define PER_CPU_SHARED_ALIGNED_SECTION "" 103 #define PER_CPU_ALIGNED_SECTION "..shared_aligned" 104 #define PER_CPU_FIRST_SECTION "" 105 106 #endif 107 108 #ifndef PER_CPU_ATTRIBUTES 109 #define PER_CPU_ATTRIBUTES 110 #endif 111 112 #ifndef PER_CPU_DEF_ATTRIBUTES 113 #define PER_CPU_DEF_ATTRIBUTES 114 #endif 115 116 #endif /* _ASM_GENERIC_PERCPU_H_ */ 117