diff options
| -rw-r--r-- | include/asm-alpha/percpu.h | 72 |
1 files changed, 71 insertions, 1 deletions
diff --git a/include/asm-alpha/percpu.h b/include/asm-alpha/percpu.h index 48348fe34c19..82e8a94b4b2f 100644 --- a/include/asm-alpha/percpu.h +++ b/include/asm-alpha/percpu.h @@ -1,6 +1,76 @@ #ifndef __ALPHA_PERCPU_H #define __ALPHA_PERCPU_H +#include <linux/compiler.h> +#include <linux/threads.h> -#include <asm-generic/percpu.h> +/* + * Determine the real variable name from the name visible in the + * kernel sources. + */ +#define per_cpu_var(var) per_cpu__##var + +#ifdef CONFIG_SMP + +/* + * per_cpu_offset() is the offset that has to be added to a + * percpu variable to get to the instance for a certain processor. + */ +extern unsigned long __per_cpu_offset[NR_CPUS]; + +#define per_cpu_offset(x) (__per_cpu_offset[x]) + +#define __my_cpu_offset per_cpu_offset(raw_smp_processor_id()) +#ifdef CONFIG_DEBUG_PREEMPT +#define my_cpu_offset per_cpu_offset(smp_processor_id()) +#else +#define my_cpu_offset __my_cpu_offset +#endif + +#ifndef MODULE +#define SHIFT_PERCPU_PTR(var, offset) RELOC_HIDE(&per_cpu_var(var), (offset)) +#define PER_CPU_ATTRIBUTES +#else +/* + * To calculate addresses of locally defined variables, GCC uses 32-bit + * displacement from the GP. Which doesn't work for per cpu variables in + * modules, as an offset to the kernel per cpu area is way above 4G. + * + * This forces allocation of a GOT entry for per cpu variable using + * ldq instruction with a 'literal' relocation. + */ +#define SHIFT_PERCPU_PTR(var, offset) ({ \ + extern int simple_identifier_##var(void); \ + unsigned long __ptr, tmp_gp; \ + asm ( "br %1, 1f \n\ + 1: ldgp %1, 0(%1) \n\ + ldq %0, per_cpu__" #var"(%1)\t!literal" \ + : "=&r"(__ptr), "=&r"(tmp_gp)); \ + (typeof(&per_cpu_var(var)))(__ptr + (offset)); }) + +#define PER_CPU_ATTRIBUTES __used + +#endif /* MODULE */ + +/* + * A percpu variable may point to a discarded regions. The following are + * established ways to produce a usable pointer from the percpu variable + * offset. + */ +#define per_cpu(var, cpu) \ + (*SHIFT_PERCPU_PTR(var, per_cpu_offset(cpu))) +#define __get_cpu_var(var) \ + (*SHIFT_PERCPU_PTR(var, my_cpu_offset)) +#define __raw_get_cpu_var(var) \ + (*SHIFT_PERCPU_PTR(var, __my_cpu_offset)) + +#else /* ! SMP */ + +#define per_cpu(var, cpu) (*((void)(cpu), &per_cpu_var(var))) +#define __get_cpu_var(var) per_cpu_var(var) +#define __raw_get_cpu_var(var) per_cpu_var(var) + +#endif /* SMP */ + +#define DECLARE_PER_CPU(type, name) extern __typeof__(type) per_cpu_var(name) #endif /* __ALPHA_PERCPU_H */ |