[linux-block.git] / include / asm-alpha / percpu.h

#ifndef __ALPHA_PERCPU_H
#define __ALPHA_PERCPU_H
#include <linux/compiler.h>
#include <linux/threads.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)

#define PER_CPU_ATTRIBUTES

#endif /* SMP */

#define DECLARE_PER_CPU(type, name) extern __typeof__(type) per_cpu_var(name)

#endif /* __ALPHA_PERCPU_H */
Commit	Line	Data
1da177e4 LT	1	#ifndef __ALPHA_PERCPU_H
1da177e4 LT	2	#define __ALPHA_PERCPU_H
9267b4b3 IK	3	#include <linux/compiler.h>
9267b4b3 IK	4	#include <linux/threads.h>
1da177e4	5
9267b4b3 IK	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
72c6e251 TK	72	#define PER_CPU_ATTRIBUTES
72c6e251 TK	73
9267b4b3 IK	74	#endif /* SMP */
	75
	76	#define DECLARE_PER_CPU(type, name) extern __typeof__(type) per_cpu_var(name)
1da177e4 LT	77
1da177e4 LT	78	#endif /* __ALPHA_PERCPU_H */