include/vdso/datapage.h

Source file repositories/reference/linux-study-clean/include/vdso/datapage.h

File Facts

System
Linux kernel
Corpus path
include/vdso/datapage.h
Extension
.h
Size
5996 bytes
Lines
203
Domain
Repository Root And Misc
Bucket
include
Inferred role
Repository Root And Misc: implementation source
Status
source implementation candidate

Why This File Exists

Top-level or miscellaneous repository surface. Use this as map coverage unless a later manual pass promotes the file into a deeper subsystem dossier.

Dependency Surface

Detected Declarations

Annotated Snippet

struct arch_vdso_time_data {};
#endif

#if defined(CONFIG_ARCH_HAS_VDSO_ARCH_DATA)
#include <asm/vdso/arch_data.h>
#else
struct vdso_arch_data {
	/* Needed for the generic code, never actually used at runtime */
	char __unused;
};
#endif

#define VDSO_BASES	(CLOCK_TAI + 1)
#define VDSO_BASE_AUX	0
#define VDSO_HRES	(BIT(CLOCK_REALTIME)		| \
			 BIT(CLOCK_MONOTONIC)		| \
			 BIT(CLOCK_BOOTTIME)		| \
			 BIT(CLOCK_TAI))
#define VDSO_COARSE	(BIT(CLOCK_REALTIME_COARSE)	| \
			 BIT(CLOCK_MONOTONIC_COARSE))
#define VDSO_RAW	(BIT(CLOCK_MONOTONIC_RAW))
#define VDSO_AUX	__GENMASK(CLOCK_AUX_LAST, CLOCK_AUX)

#define CS_HRES_COARSE	0
#define CS_RAW		1
#define CS_BASES	(CS_RAW + 1)

/**
 * struct vdso_timestamp - basetime per clock_id
 * @sec:	seconds
 * @nsec:	nanoseconds
 *
 * There is one vdso_timestamp object in vvar for each vDSO-accelerated
 * clock_id. For high-resolution clocks, this encodes the time
 * corresponding to vdso_time_data.cycle_last. For coarse clocks this encodes
 * the actual time.
 *
 * To be noticed that for highres clocks nsec is left-shifted by
 * vdso_time_data[x].shift.
 */
struct vdso_timestamp {
	u64	sec;
	u64	nsec;
};

/**
 * struct vdso_clock - vdso per clocksource datapage representation
 * @seq:		timebase sequence counter
 * @clock_mode:		clock mode
 * @cycle_last:		timebase at clocksource init
 * @max_cycles:		maximum cycles which won't overflow 64bit multiplication
 * @mask:		clocksource mask
 * @mult:		clocksource multiplier
 * @shift:		clocksource shift
 * @basetime:		basetime per clock_id
 * @offset:		time namespace offset per clock_id
 *
 * See also struct vdso_time_data for basic access and ordering information as
 * struct vdso_clock is used there.
 *
 * @basetime is used to store the base time for the system wide time getter
 * VVAR page.
 *
 * @offset is used by the special time namespace VVAR pages which are
 * installed instead of the real VVAR page. These namespace pages must set
 * @seq to 1 and @clock_mode to VDSO_CLOCKMODE_TIMENS to force the code into
 * the time namespace slow path. The namespace aware functions retrieve the
 * real system wide VVAR page, read host time and add the per clock offset.
 * For clocks which are not affected by time namespace adjustment the
 * offset must be zero.
 */
struct vdso_clock {
	u32			seq;

	s32			clock_mode;
	u64			cycle_last;
#ifdef CONFIG_GENERIC_VDSO_OVERFLOW_PROTECT
	u64			max_cycles;
#endif
	u64			mask;
	u32			mult;
	u32			shift;

	union {
		struct vdso_timestamp	basetime[VDSO_BASES];
		struct timens_offset	offset[VDSO_BASES];
	};
};

/**

Annotation

Implementation Notes