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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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#ifndef _LINUX_PERCPU_DEFS_H#define _LINUX_PERCPU_DEFS_H
#ifdef CONFIG_SMP
#ifdef MODULE#define PER_CPU_SHARED_ALIGNED_SECTION ""#define PER_CPU_ALIGNED_SECTION ""#else#define PER_CPU_SHARED_ALIGNED_SECTION "..shared_aligned"#define PER_CPU_ALIGNED_SECTION "..shared_aligned"#endif
#else
#define PER_CPU_SHARED_ALIGNED_SECTION ""#define PER_CPU_ALIGNED_SECTION "..shared_aligned"
#endif
/* * 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) \ __percpu __attribute__((section(PER_CPU_BASE_SECTION sec))) \ PER_CPU_ATTRIBUTES
#define __PCPU_DUMMY_ATTRS \ __section(".discard") __attribute__((unused))
/* * 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 set * CONFIG_ARCH_MODULE_NEEDS_WEAK_PER_CPU 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(CONFIG_ARCH_MODULE_NEEDS_WEAK_PER_CPU) && defined(MODULE)) || \ 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) 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; \ extern __PCPU_ATTRS(sec) __typeof__(type) name; \ __PCPU_ATTRS(sec) __weak __typeof__(type) name#else/* * Normal declaration and definition macros. */#define DECLARE_PER_CPU_SECTION(type, name, sec) \ extern __PCPU_ATTRS(sec) __typeof__(type) name
#define DEFINE_PER_CPU_SECTION(type, name, sec) \ __PCPU_ATTRS(sec) __typeof__(type) 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 are frequently * accessed and should be in a single cacheline. * * For use only by architecture and core code. Only use scalar or pointer * types to maximize density. */#define DECLARE_PER_CPU_CACHE_HOT(type, name) \ DECLARE_PER_CPU_SECTION(type, name, "..hot.." #name)
#define DEFINE_PER_CPU_CACHE_HOT(type, name) \ DEFINE_PER_CPU_SECTION(type, name, "..hot.." #name)
/* * 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)
/* * Declaration/definition used for per-CPU variables that must be read mostly. */#define DECLARE_PER_CPU_READ_MOSTLY(type, name) \ DECLARE_PER_CPU_SECTION(type, name, "..read_mostly")
#define DEFINE_PER_CPU_READ_MOSTLY(type, name) \ DEFINE_PER_CPU_SECTION(type, name, "..read_mostly")
/* * Declaration/definition used for per-CPU variables that should be accessed * as decrypted when memory encryption is enabled in the guest. */#ifdef CONFIG_AMD_MEM_ENCRYPT#define DECLARE_PER_CPU_DECRYPTED(type, name) \ DECLARE_PER_CPU_SECTION(type, name, "..decrypted")
#define DEFINE_PER_CPU_DECRYPTED(type, name) \ DEFINE_PER_CPU_SECTION(type, name, "..decrypted")#else#define DEFINE_PER_CPU_DECRYPTED(type, name) DEFINE_PER_CPU(type, name)#endif
/* * Intermodule exports for per-CPU variables. sparse forgets about * address space across EXPORT_SYMBOL(), change EXPORT_SYMBOL() to * noop if __CHECKER__. */#ifndef __CHECKER__#define EXPORT_PER_CPU_SYMBOL(var) EXPORT_SYMBOL(var)#define EXPORT_PER_CPU_SYMBOL_GPL(var) EXPORT_SYMBOL_GPL(var)#else#define EXPORT_PER_CPU_SYMBOL(var)#define EXPORT_PER_CPU_SYMBOL_GPL(var)#endif
/* * Accessors and operations. */#ifndef __ASSEMBLY__
/* * __verify_pcpu_ptr() verifies @ptr is a percpu pointer without evaluating * @ptr and is invoked once before a percpu area is accessed by all * accessors and operations. This is performed in the generic part of * percpu and arch overrides don't need to worry about it; however, if an * arch wants to implement an arch-specific percpu accessor or operation, * it may use __verify_pcpu_ptr() to verify the parameters. * * + 0 is required in order to convert the pointer type from a * potential array type to a pointer to a single item of the array. */#define __verify_pcpu_ptr(ptr) \do { \ const void __percpu *__vpp_verify = (typeof((ptr) + 0))NULL; \ (void)__vpp_verify; \} while (0)
#define PERCPU_PTR(__p) \ (TYPEOF_UNQUAL(*(__p)) __force __kernel *)((__force unsigned long)(__p))
#ifdef CONFIG_SMP
/* * Add an offset to a pointer. Use RELOC_HIDE() to prevent the compiler * from making incorrect assumptions about the pointer value. */#define SHIFT_PERCPU_PTR(__p, __offset) \ RELOC_HIDE(PERCPU_PTR(__p), (__offset))
#define per_cpu_ptr(ptr, cpu) \({ \ __verify_pcpu_ptr(ptr); \ SHIFT_PERCPU_PTR((ptr), per_cpu_offset((cpu))); \})
#define raw_cpu_ptr(ptr) \({ \ __verify_pcpu_ptr(ptr); \ arch_raw_cpu_ptr(ptr); \})
#ifdef CONFIG_DEBUG_PREEMPT#define this_cpu_ptr(ptr) \({ \ __verify_pcpu_ptr(ptr); \ SHIFT_PERCPU_PTR(ptr, my_cpu_offset); \})#else#define this_cpu_ptr(ptr) raw_cpu_ptr(ptr)#endif
#else /* CONFIG_SMP */
#define per_cpu_ptr(ptr, cpu) \({ \ (void)(cpu); \ __verify_pcpu_ptr(ptr); \ PERCPU_PTR(ptr); \})
#define raw_cpu_ptr(ptr) per_cpu_ptr(ptr, 0)#define this_cpu_ptr(ptr) raw_cpu_ptr(ptr)
#endif /* CONFIG_SMP */
#define per_cpu(var, cpu) (*per_cpu_ptr(&(var), cpu))
/* * Must be an lvalue. Since @var must be a simple identifier, * we force a syntax error here if it isn't. */#define get_cpu_var(var) \(*({ \ preempt_disable(); \ this_cpu_ptr(&var); \}))
/* * The weird & is necessary because sparse considers (void)(var) to be * a direct dereference of percpu variable (var). */#define put_cpu_var(var) \do { \ (void)&(var); \ preempt_enable(); \} while (0)
#define get_cpu_ptr(var) \({ \ preempt_disable(); \ this_cpu_ptr(var); \})
#define put_cpu_ptr(var) \do { \ (void)(var); \ preempt_enable(); \} while (0)
/* * Branching function to split up a function into a set of functions that * are called for different scalar sizes of the objects handled. */
extern void __bad_size_call_parameter(void);
#ifdef CONFIG_DEBUG_PREEMPTextern void __this_cpu_preempt_check(const char *op);#elsestatic __always_inline void __this_cpu_preempt_check(const char *op) { }#endif
#define __pcpu_size_call_return(stem, variable) \({ \ TYPEOF_UNQUAL(variable) pscr_ret__; \ __verify_pcpu_ptr(&(variable)); \ switch(sizeof(variable)) { \ case 1: pscr_ret__ = stem##1(variable); break; \ case 2: pscr_ret__ = stem##2(variable); break; \ case 4: pscr_ret__ = stem##4(variable); break; \ case 8: pscr_ret__ = stem##8(variable); break; \ default: \ __bad_size_call_parameter(); break; \ } \ pscr_ret__; \})
#define __pcpu_size_call_return2(stem, variable, ...) \({ \ TYPEOF_UNQUAL(variable) pscr2_ret__; \ __verify_pcpu_ptr(&(variable)); \ switch(sizeof(variable)) { \ case 1: pscr2_ret__ = stem##1(variable, __VA_ARGS__); break; \ case 2: pscr2_ret__ = stem##2(variable, __VA_ARGS__); break; \ case 4: pscr2_ret__ = stem##4(variable, __VA_ARGS__); break; \ case 8: pscr2_ret__ = stem##8(variable, __VA_ARGS__); break; \ default: \ __bad_size_call_parameter(); break; \ } \ pscr2_ret__; \})
#define __pcpu_size_call_return2bool(stem, variable, ...) \({ \ bool pscr2_ret__; \ __verify_pcpu_ptr(&(variable)); \ switch(sizeof(variable)) { \ case 1: pscr2_ret__ = stem##1(variable, __VA_ARGS__); break; \ case 2: pscr2_ret__ = stem##2(variable, __VA_ARGS__); break; \ case 4: pscr2_ret__ = stem##4(variable, __VA_ARGS__); break; \ case 8: pscr2_ret__ = stem##8(variable, __VA_ARGS__); break; \ default: \ __bad_size_call_parameter(); break; \ } \ pscr2_ret__; \})
#define __pcpu_size_call(stem, variable, ...) \do { \ __verify_pcpu_ptr(&(variable)); \ switch(sizeof(variable)) { \ case 1: stem##1(variable, __VA_ARGS__);break; \ case 2: stem##2(variable, __VA_ARGS__);break; \ case 4: stem##4(variable, __VA_ARGS__);break; \ case 8: stem##8(variable, __VA_ARGS__);break; \ default: \ __bad_size_call_parameter();break; \ } \} while (0)
/* * this_cpu operations (C) 2008-2013 Christoph Lameter <cl@gentwo.org> * * Optimized manipulation for memory allocated through the per cpu * allocator or for addresses of per cpu variables. * * These operation guarantee exclusivity of access for other operations * on the *same* processor. The assumption is that per cpu data is only * accessed by a single processor instance (the current one). * * The arch code can provide optimized implementation by defining macros * for certain scalar sizes. F.e. provide this_cpu_add_2() to provide per * cpu atomic operations for 2 byte sized RMW actions. If arch code does * not provide operations for a scalar size then the fallback in the * generic code will be used. * * cmpxchg_double replaces two adjacent scalars at once. The first two * parameters are per cpu variables which have to be of the same size. A * truth value is returned to indicate success or failure (since a double * register result is difficult to handle). There is very limited hardware * support for these operations, so only certain sizes may work. */
/* * Operations for contexts where we do not want to do any checks for * preemptions. Unless strictly necessary, always use [__]this_cpu_*() * instead. * * If there is no other protection through preempt disable and/or disabling * interrupts then one of these RMW operations can show unexpected behavior * because the execution thread was rescheduled on another processor or an * interrupt occurred and the same percpu variable was modified from the * interrupt context. */#define raw_cpu_read(pcp) __pcpu_size_call_return(raw_cpu_read_, pcp)#define raw_cpu_write(pcp, val) __pcpu_size_call(raw_cpu_write_, pcp, val)#define raw_cpu_add(pcp, val) __pcpu_size_call(raw_cpu_add_, pcp, val)#define raw_cpu_and(pcp, val) __pcpu_size_call(raw_cpu_and_, pcp, val)#define raw_cpu_or(pcp, val) __pcpu_size_call(raw_cpu_or_, pcp, val)#define raw_cpu_add_return(pcp, val) __pcpu_size_call_return2(raw_cpu_add_return_, pcp, val)#define raw_cpu_xchg(pcp, nval) __pcpu_size_call_return2(raw_cpu_xchg_, pcp, nval)#define raw_cpu_cmpxchg(pcp, oval, nval) \ __pcpu_size_call_return2(raw_cpu_cmpxchg_, pcp, oval, nval)#define raw_cpu_try_cmpxchg(pcp, ovalp, nval) \ __pcpu_size_call_return2bool(raw_cpu_try_cmpxchg_, pcp, ovalp, nval)#define raw_cpu_sub(pcp, val) raw_cpu_add(pcp, -(val))#define raw_cpu_inc(pcp) raw_cpu_add(pcp, 1)#define raw_cpu_dec(pcp) raw_cpu_sub(pcp, 1)#define raw_cpu_sub_return(pcp, val) raw_cpu_add_return(pcp, -(typeof(pcp))(val))#define raw_cpu_inc_return(pcp) raw_cpu_add_return(pcp, 1)#define raw_cpu_dec_return(pcp) raw_cpu_add_return(pcp, -1)
/* * Operations for contexts that are safe from preemption/interrupts. These * operations verify that preemption is disabled. */#define __this_cpu_read(pcp) \({ \ __this_cpu_preempt_check("read"); \ raw_cpu_read(pcp); \})
#define __this_cpu_write(pcp, val) \({ \ __this_cpu_preempt_check("write"); \ raw_cpu_write(pcp, val); \})
#define __this_cpu_add(pcp, val) \({ \ __this_cpu_preempt_check("add"); \ raw_cpu_add(pcp, val); \})
#define __this_cpu_and(pcp, val) \({ \ __this_cpu_preempt_check("and"); \ raw_cpu_and(pcp, val); \})
#define __this_cpu_or(pcp, val) \({ \ __this_cpu_preempt_check("or"); \ raw_cpu_or(pcp, val); \})
#define __this_cpu_add_return(pcp, val) \({ \ __this_cpu_preempt_check("add_return"); \ raw_cpu_add_return(pcp, val); \})
#define __this_cpu_xchg(pcp, nval) \({ \ __this_cpu_preempt_check("xchg"); \ raw_cpu_xchg(pcp, nval); \})
#define __this_cpu_cmpxchg(pcp, oval, nval) \({ \ __this_cpu_preempt_check("cmpxchg"); \ raw_cpu_cmpxchg(pcp, oval, nval); \})
#define __this_cpu_try_cmpxchg(pcp, ovalp, nval) \({ \ __this_cpu_preempt_check("try_cmpxchg"); \ raw_cpu_try_cmpxchg(pcp, ovalp, nval); \})
#define __this_cpu_sub(pcp, val) __this_cpu_add(pcp, -(typeof(pcp))(val))#define __this_cpu_inc(pcp) __this_cpu_add(pcp, 1)#define __this_cpu_dec(pcp) __this_cpu_sub(pcp, 1)#define __this_cpu_sub_return(pcp, val) __this_cpu_add_return(pcp, -(typeof(pcp))(val))#define __this_cpu_inc_return(pcp) __this_cpu_add_return(pcp, 1)#define __this_cpu_dec_return(pcp) __this_cpu_add_return(pcp, -1)
/* * Operations with implied preemption/interrupt protection. These * operations can be used without worrying about preemption or interrupt. */#define this_cpu_read(pcp) __pcpu_size_call_return(this_cpu_read_, pcp)#define this_cpu_write(pcp, val) __pcpu_size_call(this_cpu_write_, pcp, val)#define this_cpu_add(pcp, val) __pcpu_size_call(this_cpu_add_, pcp, val)#define this_cpu_and(pcp, val) __pcpu_size_call(this_cpu_and_, pcp, val)#define this_cpu_or(pcp, val) __pcpu_size_call(this_cpu_or_, pcp, val)#define this_cpu_add_return(pcp, val) __pcpu_size_call_return2(this_cpu_add_return_, pcp, val)#define this_cpu_xchg(pcp, nval) __pcpu_size_call_return2(this_cpu_xchg_, pcp, nval)#define this_cpu_cmpxchg(pcp, oval, nval) \ __pcpu_size_call_return2(this_cpu_cmpxchg_, pcp, oval, nval)#define this_cpu_try_cmpxchg(pcp, ovalp, nval) \ __pcpu_size_call_return2bool(this_cpu_try_cmpxchg_, pcp, ovalp, nval)#define this_cpu_sub(pcp, val) this_cpu_add(pcp, -(typeof(pcp))(val))#define this_cpu_inc(pcp) this_cpu_add(pcp, 1)#define this_cpu_dec(pcp) this_cpu_sub(pcp, 1)#define this_cpu_sub_return(pcp, val) this_cpu_add_return(pcp, -(typeof(pcp))(val))#define this_cpu_inc_return(pcp) this_cpu_add_return(pcp, 1)#define this_cpu_dec_return(pcp) this_cpu_add_return(pcp, -1)
#endif /* __ASSEMBLY__ */#endif /* _LINUX_PERCPU_DEFS_H */