alpha: fix module load failures on smp (bug #10926)

#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 */