percpu: make the asm-generic/percpu.h more "generic"
- add support for PER_CPU_ATTRIBUTES - fix generic smp percpu_modcopy to use per_cpu_offset() macro. Add the ability to use generic/percpu even if the arch needs to override several aspects of its operations. This will enable the use of generic percpu.h for all arches. An arch may define: __per_cpu_offset Do not use the generic pointer array. Arch must define per_cpu_offset(cpu) (used by x86_64, s390). __my_cpu_offset Can be defined to provide an optimized way to determine the offset for variables of the currently executing processor. Used by ia64, x86_64, x86_32, sparc64, s/390. SHIFT_PTR(ptr, offset) If an arch defines it then special handling of pointer arithmentic may be implemented. Used by s/390. (Some of these special percpu arch implementations may be later consolidated so that there are less cases to deal with.) Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Mike Travis <travis@sgi.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
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@ -947,7 +947,7 @@ percpu_modcopy (void *pcpudst, const void *src, unsigned long size)
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{
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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], src, size);
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memcpy(pcpudst + per_cpu_offset(i), src, size);
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}
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}
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#endif /* CONFIG_SMP */
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@ -3,35 +3,87 @@
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#include <linux/compiler.h>
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#include <linux/threads.h>
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/*
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* Determine the real variable name from the name visible in the
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* kernel sources.
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*/
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#define per_cpu_var(var) per_cpu__##var
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#ifdef CONFIG_SMP
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/*
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* per_cpu_offset() is the offset that has to be added to a
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* percpu variable to get to the instance for a certain processor.
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*
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* Most arches use the __per_cpu_offset array for those offsets but
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* some arches have their own ways of determining the offset (x86_64, s390).
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*/
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#ifndef __per_cpu_offset
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extern unsigned long __per_cpu_offset[NR_CPUS];
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#define per_cpu_offset(x) (__per_cpu_offset[x])
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#endif
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/* var is in discarded region: offset to particular copy we want */
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#define per_cpu(var, cpu) (*({ \
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extern int simple_identifier_##var(void); \
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RELOC_HIDE(&per_cpu__##var, __per_cpu_offset[cpu]); }))
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#define __get_cpu_var(var) per_cpu(var, smp_processor_id())
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#define __raw_get_cpu_var(var) per_cpu(var, raw_smp_processor_id())
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/*
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* Determine the offset for the currently active processor.
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* An arch may define __my_cpu_offset to provide a more effective
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* means of obtaining the offset to the per cpu variables of the
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* current processor.
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*/
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#ifndef __my_cpu_offset
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#define __my_cpu_offset per_cpu_offset(raw_smp_processor_id())
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#define my_cpu_offset per_cpu_offset(smp_processor_id())
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#else
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#define my_cpu_offset __my_cpu_offset
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#endif
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/*
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* Add a offset to a pointer but keep the pointer as is.
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*
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* Only S390 provides its own means of moving the pointer.
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*/
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#ifndef SHIFT_PERCPU_PTR
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#define SHIFT_PERCPU_PTR(__p, __offset) RELOC_HIDE((__p), (__offset))
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#endif
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/*
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* A percpu variable may point to a discarded reghions. The following are
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* established ways to produce a usable pointer from the percpu variable
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* offset.
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*/
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#define per_cpu(var, cpu) \
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(*SHIFT_PERCPU_PTR(&per_cpu_var(var), per_cpu_offset(cpu)))
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#define __get_cpu_var(var) \
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(*SHIFT_PERCPU_PTR(&per_cpu_var(var), my_cpu_offset))
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#define __raw_get_cpu_var(var) \
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(*SHIFT_PERCPU_PTR(&per_cpu_var(var), __my_cpu_offset))
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#ifdef CONFIG_ARCH_SETS_UP_PER_CPU_AREA
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extern void setup_per_cpu_areas(void);
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#endif
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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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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 per_cpu(var, cpu) (*((void)(cpu), &per_cpu__##var))
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#define __get_cpu_var(var) per_cpu__##var
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#define __raw_get_cpu_var(var) per_cpu__##var
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#define per_cpu(var, cpu) (*((void)(cpu), &per_cpu_var(var)))
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#define __get_cpu_var(var) per_cpu_var(var)
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#define __raw_get_cpu_var(var) per_cpu_var(var)
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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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#ifndef PER_CPU_ATTRIBUTES
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#define PER_CPU_ATTRIBUTES
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#endif
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#define DECLARE_PER_CPU(type, name) extern PER_CPU_ATTRIBUTES \
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__typeof__(type) per_cpu_var(name)
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#endif /* _ASM_GENERIC_PERCPU_H_ */
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