arch/x86/include/asm/percpu.h

Source file repositories/reference/linux-study-clean/arch/x86/include/asm/percpu.h

File Facts

System
Linux kernel
Corpus path
arch/x86/include/asm/percpu.h
Extension
.h
Size
23054 bytes
Lines
664
Domain
Architecture Layer
Bucket
arch/x86
Inferred role
Architecture Layer: implementation source
Status
source implementation candidate

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

#ifndef _ASM_X86_PERCPU_H
#define _ASM_X86_PERCPU_H

#ifdef CONFIG_X86_64
# define __percpu_seg		gs
# define __percpu_rel		(%rip)
#else
# define __percpu_seg		fs
# define __percpu_rel
#endif

#ifdef __ASSEMBLER__

#ifdef CONFIG_SMP
# define __percpu		%__percpu_seg:
#else
# define __percpu
#endif

#define PER_CPU_VAR(var)	__percpu(var)__percpu_rel

#else /* !__ASSEMBLER__: */

#include <linux/args.h>
#include <linux/bits.h>
#include <linux/build_bug.h>
#include <linux/stringify.h>
#include <asm/asm.h>

#ifdef CONFIG_SMP

#define __force_percpu_prefix	"%%"__stringify(__percpu_seg)":"

#ifdef CONFIG_CC_HAS_NAMED_AS

#ifdef __CHECKER__
# define __seg_gs		__attribute__((address_space(__seg_gs)))
# define __seg_fs		__attribute__((address_space(__seg_fs)))
#endif

#define __percpu_prefix

#else /* !CONFIG_CC_HAS_NAMED_AS: */

#define __percpu_prefix		__force_percpu_prefix

#endif /* CONFIG_CC_HAS_NAMED_AS */

/*
 * Compared to the generic __my_cpu_offset version, the following
 * saves one instruction and avoids clobbering a temp register.
 */
#define __my_cpu_offset		this_cpu_read(this_cpu_off)

/*
 * arch_raw_cpu_ptr should not be used in 32-bit VDSO for a 64-bit
 * kernel, because games are played with CONFIG_X86_64 there and
 * sizeof(this_cpu_off) becames 4.
 */
#ifndef BUILD_VDSO32_64
#define arch_raw_cpu_ptr(_ptr)						\
({									\
	unsigned long tcp_ptr__ = raw_cpu_read_long(this_cpu_off);	\
									\
	tcp_ptr__ += (__force unsigned long)(_ptr);			\
	(TYPEOF_UNQUAL(*(_ptr)) __force __kernel *)tcp_ptr__;		\
})
#else
#define arch_raw_cpu_ptr(_ptr)						\
({									\
	BUILD_BUG();							\
	(TYPEOF_UNQUAL(*(_ptr)) __force __kernel *)0;			\
})
#endif

#define PER_CPU_VAR(var)	%__percpu_seg:(var)__percpu_rel

#else /* !CONFIG_SMP: */

#define __force_percpu_prefix
#define __percpu_prefix

#define PER_CPU_VAR(var)	(var)__percpu_rel

#endif /* CONFIG_SMP */

#if defined(CONFIG_USE_X86_SEG_SUPPORT) && defined(USE_TYPEOF_UNQUAL)
# define __my_cpu_type(var)	typeof(var)
# define __my_cpu_ptr(ptr)	(ptr)
# define __my_cpu_var(var)	(var)

Annotation

Implementation Notes