1 #ifndef __ALPHA_PERCPU_H 2 #define __ALPHA_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 extern unsigned long __per_cpu_offset[NR_CPUS]; 19 20 #define per_cpu_offset(x) (__per_cpu_offset[x]) 21 22 #define __my_cpu_offset per_cpu_offset(raw_smp_processor_id()) 23 #ifdef CONFIG_DEBUG_PREEMPT 24 #define my_cpu_offset per_cpu_offset(smp_processor_id()) 25 #else 26 #define my_cpu_offset __my_cpu_offset 27 #endif 28 29 #ifndef MODULE 30 #define SHIFT_PERCPU_PTR(var, offset) RELOC_HIDE(&per_cpu_var(var), (offset)) 31 #define PER_CPU_ATTRIBUTES 32 #else 33 /* 34 * To calculate addresses of locally defined variables, GCC uses 32-bit 35 * displacement from the GP. Which doesn't work for per cpu variables in 36 * modules, as an offset to the kernel per cpu area is way above 4G. 37 * 38 * This forces allocation of a GOT entry for per cpu variable using 39 * ldq instruction with a 'literal' relocation. 40 */ 41 #define SHIFT_PERCPU_PTR(var, offset) ({ \ 42 extern int simple_identifier_##var(void); \ 43 unsigned long __ptr, tmp_gp; \ 44 asm ( "br %1, 1f \n\ 45 1: ldgp %1, 0(%1) \n\ 46 ldq %0, per_cpu__" #var"(%1)\t!literal" \ 47 : "=&r"(__ptr), "=&r"(tmp_gp)); \ 48 (typeof(&per_cpu_var(var)))(__ptr + (offset)); }) 49 50 #define PER_CPU_ATTRIBUTES __used 51 52 #endif /* MODULE */ 53 54 /* 55 * A percpu variable may point to a discarded regions. The following are 56 * established ways to produce a usable pointer from the percpu variable 57 * offset. 58 */ 59 #define per_cpu(var, cpu) \ 60 (*SHIFT_PERCPU_PTR(var, per_cpu_offset(cpu))) 61 #define __get_cpu_var(var) \ 62 (*SHIFT_PERCPU_PTR(var, my_cpu_offset)) 63 #define __raw_get_cpu_var(var) \ 64 (*SHIFT_PERCPU_PTR(var, __my_cpu_offset)) 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 #define PER_CPU_ATTRIBUTES 73 74 #endif /* SMP */ 75 76 #define DECLARE_PER_CPU(type, name) extern __typeof__(type) per_cpu_var(name) 77 78 #endif /* __ALPHA_PERCPU_H */ 79