145 lines
5.1 KiB
C
145 lines
5.1 KiB
C
#ifndef _LINUX_PERCPU_DEFS_H
|
|
#define _LINUX_PERCPU_DEFS_H
|
|
|
|
/*
|
|
* Determine the real variable name from the name visible in the
|
|
* kernel sources.
|
|
*/
|
|
#define per_cpu_var(var) per_cpu__##var
|
|
|
|
/*
|
|
* Base implementations of per-CPU variable declarations and definitions, where
|
|
* the section in which the variable is to be placed is provided by the
|
|
* 'sec' argument. This may be used to affect the parameters governing the
|
|
* variable's storage.
|
|
*
|
|
* NOTE! The sections for the DECLARE and for the DEFINE must match, lest
|
|
* linkage errors occur due the compiler generating the wrong code to access
|
|
* that section.
|
|
*/
|
|
#define __PCPU_ATTRS(sec) \
|
|
__attribute__((section(PER_CPU_BASE_SECTION sec))) \
|
|
PER_CPU_ATTRIBUTES
|
|
|
|
#define __PCPU_DUMMY_ATTRS \
|
|
__attribute__((section(".discard"), unused))
|
|
|
|
/*
|
|
* s390 and alpha modules require percpu variables to be defined as
|
|
* weak to force the compiler to generate GOT based external
|
|
* references for them. This is necessary because percpu sections
|
|
* will be located outside of the usually addressable area.
|
|
*
|
|
* This definition puts the following two extra restrictions when
|
|
* defining percpu variables.
|
|
*
|
|
* 1. The symbol must be globally unique, even the static ones.
|
|
* 2. Static percpu variables cannot be defined inside a function.
|
|
*
|
|
* Archs which need weak percpu definitions should define
|
|
* ARCH_NEEDS_WEAK_PER_CPU in asm/percpu.h when necessary.
|
|
*
|
|
* To ensure that the generic code observes the above two
|
|
* restrictions, if CONFIG_DEBUG_FORCE_WEAK_PER_CPU is set weak
|
|
* definition is used for all cases.
|
|
*/
|
|
#if defined(ARCH_NEEDS_WEAK_PER_CPU) || defined(CONFIG_DEBUG_FORCE_WEAK_PER_CPU)
|
|
/*
|
|
* __pcpu_scope_* dummy variable is used to enforce scope. It
|
|
* receives the static modifier when it's used in front of
|
|
* DEFINE_PER_CPU() and will trigger build failure if
|
|
* DECLARE_PER_CPU() is used for the same variable.
|
|
*
|
|
* __pcpu_unique_* dummy variable is used to enforce symbol uniqueness
|
|
* such that hidden weak symbol collision, which will cause unrelated
|
|
* variables to share the same address, can be detected during build.
|
|
*/
|
|
#define DECLARE_PER_CPU_SECTION(type, name, sec) \
|
|
extern __PCPU_DUMMY_ATTRS char __pcpu_scope_##name; \
|
|
extern __PCPU_ATTRS(sec) __typeof__(type) per_cpu__##name
|
|
|
|
#define DEFINE_PER_CPU_SECTION(type, name, sec) \
|
|
__PCPU_DUMMY_ATTRS char __pcpu_scope_##name; \
|
|
extern __PCPU_DUMMY_ATTRS char __pcpu_unique_##name; \
|
|
__PCPU_DUMMY_ATTRS char __pcpu_unique_##name; \
|
|
__PCPU_ATTRS(sec) PER_CPU_DEF_ATTRIBUTES __weak \
|
|
__typeof__(type) per_cpu__##name
|
|
#else
|
|
/*
|
|
* Normal declaration and definition macros.
|
|
*/
|
|
#define DECLARE_PER_CPU_SECTION(type, name, sec) \
|
|
extern __PCPU_ATTRS(sec) __typeof__(type) per_cpu__##name
|
|
|
|
#define DEFINE_PER_CPU_SECTION(type, name, sec) \
|
|
__PCPU_ATTRS(sec) PER_CPU_DEF_ATTRIBUTES \
|
|
__typeof__(type) per_cpu__##name
|
|
#endif
|
|
|
|
/*
|
|
* Variant on the per-CPU variable declaration/definition theme used for
|
|
* ordinary per-CPU variables.
|
|
*/
|
|
#define DECLARE_PER_CPU(type, name) \
|
|
DECLARE_PER_CPU_SECTION(type, name, "")
|
|
|
|
#define DEFINE_PER_CPU(type, name) \
|
|
DEFINE_PER_CPU_SECTION(type, name, "")
|
|
|
|
/*
|
|
* Declaration/definition used for per-CPU variables that must come first in
|
|
* the set of variables.
|
|
*/
|
|
#define DECLARE_PER_CPU_FIRST(type, name) \
|
|
DECLARE_PER_CPU_SECTION(type, name, PER_CPU_FIRST_SECTION)
|
|
|
|
#define DEFINE_PER_CPU_FIRST(type, name) \
|
|
DEFINE_PER_CPU_SECTION(type, name, PER_CPU_FIRST_SECTION)
|
|
|
|
/*
|
|
* Declaration/definition used for per-CPU variables that must be cacheline
|
|
* aligned under SMP conditions so that, whilst a particular instance of the
|
|
* data corresponds to a particular CPU, inefficiencies due to direct access by
|
|
* other CPUs are reduced by preventing the data from unnecessarily spanning
|
|
* cachelines.
|
|
*
|
|
* An example of this would be statistical data, where each CPU's set of data
|
|
* is updated by that CPU alone, but the data from across all CPUs is collated
|
|
* by a CPU processing a read from a proc file.
|
|
*/
|
|
#define DECLARE_PER_CPU_SHARED_ALIGNED(type, name) \
|
|
DECLARE_PER_CPU_SECTION(type, name, PER_CPU_SHARED_ALIGNED_SECTION) \
|
|
____cacheline_aligned_in_smp
|
|
|
|
#define DEFINE_PER_CPU_SHARED_ALIGNED(type, name) \
|
|
DEFINE_PER_CPU_SECTION(type, name, PER_CPU_SHARED_ALIGNED_SECTION) \
|
|
____cacheline_aligned_in_smp
|
|
|
|
#define DECLARE_PER_CPU_ALIGNED(type, name) \
|
|
DECLARE_PER_CPU_SECTION(type, name, PER_CPU_ALIGNED_SECTION) \
|
|
____cacheline_aligned
|
|
|
|
#define DEFINE_PER_CPU_ALIGNED(type, name) \
|
|
DEFINE_PER_CPU_SECTION(type, name, PER_CPU_ALIGNED_SECTION) \
|
|
____cacheline_aligned
|
|
|
|
/*
|
|
* Declaration/definition used for per-CPU variables that must be page aligned.
|
|
*/
|
|
#define DECLARE_PER_CPU_PAGE_ALIGNED(type, name) \
|
|
DECLARE_PER_CPU_SECTION(type, name, ".page_aligned") \
|
|
__aligned(PAGE_SIZE)
|
|
|
|
#define DEFINE_PER_CPU_PAGE_ALIGNED(type, name) \
|
|
DEFINE_PER_CPU_SECTION(type, name, ".page_aligned") \
|
|
__aligned(PAGE_SIZE)
|
|
|
|
/*
|
|
* Intermodule exports for per-CPU variables.
|
|
*/
|
|
#define EXPORT_PER_CPU_SYMBOL(var) EXPORT_SYMBOL(per_cpu__##var)
|
|
#define EXPORT_PER_CPU_SYMBOL_GPL(var) EXPORT_SYMBOL_GPL(per_cpu__##var)
|
|
|
|
|
|
#endif /* _LINUX_PERCPU_DEFS_H */
|