forked from mirrors/linux
677243d749
Redefine __get_cpu_var() using this_cpu_ptr() which can be arch-optimized. Signed-off-by: Brian Gerst <brgerst@gmail.com> Signed-off-by: Tejun Heo <tj@kernel.org>
125 lines
3.2 KiB
C
125 lines
3.2 KiB
C
#ifndef _ASM_GENERIC_PERCPU_H_
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#define _ASM_GENERIC_PERCPU_H_
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#include <linux/compiler.h>
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#include <linux/threads.h>
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#include <linux/percpu-defs.h>
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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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/*
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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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#endif
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#ifdef CONFIG_DEBUG_PREEMPT
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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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/* Weird cast keeps both GCC and sparse happy. */
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#define SHIFT_PERCPU_PTR(__p, __offset) ({ \
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__verify_pcpu_ptr((__p)); \
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RELOC_HIDE((typeof(*(__p)) __kernel __force *)(__p), (__offset)); \
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})
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#endif
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/*
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* A percpu variable may point to a discarded regions. 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(&(var), per_cpu_offset(cpu)))
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#ifndef __this_cpu_ptr
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#define __this_cpu_ptr(ptr) SHIFT_PERCPU_PTR(ptr, __my_cpu_offset)
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#endif
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#ifdef CONFIG_DEBUG_PREEMPT
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#define this_cpu_ptr(ptr) SHIFT_PERCPU_PTR(ptr, my_cpu_offset)
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#else
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#define this_cpu_ptr(ptr) __this_cpu_ptr(ptr)
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#endif
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#define __get_cpu_var(var) (*this_cpu_ptr(&(var)))
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#define __raw_get_cpu_var(var) (*__this_cpu_ptr(&(var)))
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#ifdef CONFIG_HAVE_SETUP_PER_CPU_AREA
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extern void setup_per_cpu_areas(void);
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#endif
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#else /* ! SMP */
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#define VERIFY_PERCPU_PTR(__p) ({ \
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__verify_pcpu_ptr((__p)); \
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(typeof(*(__p)) __kernel __force *)(__p); \
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})
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#define per_cpu(var, cpu) (*((void)(cpu), VERIFY_PERCPU_PTR(&(var))))
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#define __get_cpu_var(var) (*VERIFY_PERCPU_PTR(&(var)))
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#define __raw_get_cpu_var(var) (*VERIFY_PERCPU_PTR(&(var)))
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#define this_cpu_ptr(ptr) per_cpu_ptr(ptr, 0)
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#define __this_cpu_ptr(ptr) this_cpu_ptr(ptr)
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#endif /* SMP */
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#ifndef PER_CPU_BASE_SECTION
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#ifdef CONFIG_SMP
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#define PER_CPU_BASE_SECTION ".data..percpu"
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#else
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#define PER_CPU_BASE_SECTION ".data"
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#endif
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#endif
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#ifdef CONFIG_SMP
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#ifdef MODULE
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#define PER_CPU_SHARED_ALIGNED_SECTION ""
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#define PER_CPU_ALIGNED_SECTION ""
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#else
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#define PER_CPU_SHARED_ALIGNED_SECTION "..shared_aligned"
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#define PER_CPU_ALIGNED_SECTION "..shared_aligned"
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#endif
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#define PER_CPU_FIRST_SECTION "..first"
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#else
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#define PER_CPU_SHARED_ALIGNED_SECTION ""
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#define PER_CPU_ALIGNED_SECTION "..shared_aligned"
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#define PER_CPU_FIRST_SECTION ""
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#endif
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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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#ifndef PER_CPU_DEF_ATTRIBUTES
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#define PER_CPU_DEF_ATTRIBUTES
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#endif
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#endif /* _ASM_GENERIC_PERCPU_H_ */
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