include/linux/percpu-defs.h

Source file repositories/reference/linux-study-clean/include/linux/percpu-defs.h

File Facts

System
Linux kernel
Corpus path
include/linux/percpu-defs.h
Extension
.h
Size
17813 bytes
Lines
519
Domain
Core OS
Bucket
Core Kernel Interface
Inferred role
Core OS: exported/initcall integration point
Status
integration implementation candidate

Why This File Exists

Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.

Dependency Surface

Detected Declarations

Annotated Snippet

static __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

Annotation

Implementation Notes