kernel_optimize_test/include/asm-ia64/percpu.h
Ingo Molnar ab6e14b712 ia64: on UP percpu variables are not small memory model
Tony says:

| The CONFIG_SMP=n path in ia64 makes quite radical changes ... rather
| than putting all the per-cpu stuff into the top 64K of address space
| and providing a per-cpu TLB mapping for that range to a different
| physical address ... it just makes all the per-cpu stuff link as ordinary
| variables in .data.

the new generic percpu code got confused about this as PER_CPU_ATTRIBUTES
was defined even on UP, so it picked up that small memory model - which
was not possible to get linked. The right fix is to only define that
on SMP. This resolved the build failures in my cross-compiling environment.

also link these variables into the .percpu section even on UP - some
assembly code has offset dependencies. (such as GET_IA64_MCA_DATA() in
arch/ia64/kernel/mca_asm.S)

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Tony Luck <tony.luck@intel.com>
2008-01-30 23:27:58 +01:00

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C

#ifndef _ASM_IA64_PERCPU_H
#define _ASM_IA64_PERCPU_H
/*
* Copyright (C) 2002-2003 Hewlett-Packard Co
* David Mosberger-Tang <davidm@hpl.hp.com>
*/
#define PERCPU_ENOUGH_ROOM PERCPU_PAGE_SIZE
#ifdef __ASSEMBLY__
# define THIS_CPU(var) (per_cpu__##var) /* use this to mark accesses to per-CPU variables... */
#else /* !__ASSEMBLY__ */
#include <linux/threads.h>
#ifdef CONFIG_SMP
#ifdef HAVE_MODEL_SMALL_ATTRIBUTE
# define PER_CPU_ATTRIBUTES __attribute__((__model__ (__small__)))
#endif
#define __my_cpu_offset __ia64_per_cpu_var(local_per_cpu_offset)
extern void *per_cpu_init(void);
#else /* ! SMP */
#define PER_CPU_ATTRIBUTES __attribute__((__section__(".data.percpu")))
#define per_cpu_init() (__phys_per_cpu_start)
#endif /* SMP */
/*
* Be extremely careful when taking the address of this variable! Due to virtual
* remapping, it is different from the canonical address returned by __get_cpu_var(var)!
* On the positive side, using __ia64_per_cpu_var() instead of __get_cpu_var() is slightly
* more efficient.
*/
#define __ia64_per_cpu_var(var) per_cpu__##var
#include <asm-generic/percpu.h>
/* Equal to __per_cpu_offset[smp_processor_id()], but faster to access: */
DECLARE_PER_CPU(unsigned long, local_per_cpu_offset);
#endif /* !__ASSEMBLY__ */
#endif /* _ASM_IA64_PERCPU_H */