bfe5d83419
There are several instances of per_cpu(foo, raw_smp_processor_id()), which is semantically equivalent to __get_cpu_var(foo) but without the warning that smp_processor_id() can give if CONFIG_DEBUG_PREEMPT is enabled. For those architectures with optimized per-cpu implementations, namely ia64, powerpc, s390, sparc64 and x86_64, per_cpu() turns into more and slower code than __get_cpu_var(), so it would be preferable to use __get_cpu_var on those platforms. This defines a __raw_get_cpu_var(x) macro which turns into per_cpu(x, raw_smp_processor_id()) on architectures that use the generic per-cpu implementation, and turns into __get_cpu_var(x) on the architectures that have an optimized per-cpu implementation. Signed-off-by: Paul Mackerras <paulus@samba.org> Acked-by: David S. Miller <davem@davemloft.net> Acked-by: Ingo Molnar <mingo@elte.hu> Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
71 lines
2.1 KiB
C
71 lines
2.1 KiB
C
#ifndef __ARCH_S390_PERCPU__
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#define __ARCH_S390_PERCPU__
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#include <linux/compiler.h>
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#include <asm/lowcore.h>
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#define __GENERIC_PER_CPU
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/*
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* s390 uses its own implementation for per cpu data, the offset of
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* the cpu local data area is cached in the cpu's lowcore memory.
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* For 64 bit module code s390 forces the use of a GOT slot for the
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* address of the per cpu variable. This is needed because the module
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* may be more than 4G above the per cpu area.
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*/
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#if defined(__s390x__) && defined(MODULE)
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#define __reloc_hide(var,offset) \
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(*({ unsigned long *__ptr; \
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asm ( "larl %0,per_cpu__"#var"@GOTENT" \
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: "=a" (__ptr) : "X" (per_cpu__##var) ); \
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(typeof(&per_cpu__##var))((*__ptr) + (offset)); }))
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#else
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#define __reloc_hide(var, offset) \
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(*({ unsigned long __ptr; \
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asm ( "" : "=a" (__ptr) : "0" (&per_cpu__##var) ); \
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(typeof(&per_cpu__##var)) (__ptr + (offset)); }))
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#endif
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#ifdef CONFIG_SMP
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extern unsigned long __per_cpu_offset[NR_CPUS];
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/* Separate out the type, so (int[3], foo) works. */
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#define DEFINE_PER_CPU(type, name) \
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__attribute__((__section__(".data.percpu"))) \
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__typeof__(type) per_cpu__##name
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#define __get_cpu_var(var) __reloc_hide(var,S390_lowcore.percpu_offset)
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#define __raw_get_cpu_var(var) __reloc_hide(var,S390_lowcore.percpu_offset)
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#define per_cpu(var,cpu) __reloc_hide(var,__per_cpu_offset[cpu])
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/* A macro to avoid #include hell... */
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#define percpu_modcopy(pcpudst, src, size) \
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do { \
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unsigned int __i; \
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for_each_possible_cpu(__i) \
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memcpy((pcpudst)+__per_cpu_offset[__i], \
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(src), (size)); \
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} while (0)
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#else /* ! SMP */
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#define DEFINE_PER_CPU(type, name) \
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__typeof__(type) per_cpu__##name
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#define __get_cpu_var(var) __reloc_hide(var,0)
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#define __raw_get_cpu_var(var) __reloc_hide(var,0)
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#define per_cpu(var,cpu) __reloc_hide(var,0)
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#endif /* SMP */
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#define DECLARE_PER_CPU(type, name) extern __typeof__(type) per_cpu__##name
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#define EXPORT_PER_CPU_SYMBOL(var) EXPORT_SYMBOL(per_cpu__##var)
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#define EXPORT_PER_CPU_SYMBOL_GPL(var) EXPORT_SYMBOL_GPL(per_cpu__##var)
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#endif /* __ARCH_S390_PERCPU__ */
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