arch/arm64/include/asm/vdso/gettimeofday.h

Source file repositories/reference/linux-study-clean/arch/arm64/include/asm/vdso/gettimeofday.h

File Facts

System
Linux kernel
Corpus path
arch/arm64/include/asm/vdso/gettimeofday.h
Extension
.h
Size
2594 bytes
Lines
110
Domain
Architecture Layer
Bucket
arch/arm64
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_VDSO_GETTIMEOFDAY_H
#define __ASM_VDSO_GETTIMEOFDAY_H

#ifdef __aarch64__

#ifndef __ASSEMBLER__

#include <vdso/clocksource.h>

#include <asm/alternative.h>
#include <asm/arch_timer.h>
#include <asm/barrier.h>
#include <asm/unistd.h>
#include <asm/sysreg.h>

#define VDSO_HAS_CLOCK_GETRES		1

static __always_inline
int gettimeofday_fallback(struct __kernel_old_timeval *_tv,
			  struct timezone *_tz)
{
	register struct timezone *tz asm("x1") = _tz;
	register struct __kernel_old_timeval *tv asm("x0") = _tv;
	register long ret asm ("x0");
	register long nr asm("x8") = __NR_gettimeofday;

	asm volatile(
	"       svc #0\n"
	: "=r" (ret)
	: "r" (tv), "r" (tz), "r" (nr)
	: "memory");

	return ret;
}

static __always_inline
long clock_gettime_fallback(clockid_t _clkid, struct __kernel_timespec *_ts)
{
	register struct __kernel_timespec *ts asm("x1") = _ts;
	register clockid_t clkid asm("x0") = _clkid;
	register long ret asm ("x0");
	register long nr asm("x8") = __NR_clock_gettime;

	asm volatile(
	"       svc #0\n"
	: "=r" (ret)
	: "r" (clkid), "r" (ts), "r" (nr)
	: "memory");

	return ret;
}

static __always_inline
int clock_getres_fallback(clockid_t _clkid, struct __kernel_timespec *_ts)
{
	register struct __kernel_timespec *ts asm("x1") = _ts;
	register clockid_t clkid asm("x0") = _clkid;
	register long ret asm ("x0");
	register long nr asm("x8") = __NR_clock_getres;

	asm volatile(
	"       svc #0\n"
	: "=r" (ret)
	: "r" (clkid), "r" (ts), "r" (nr)
	: "memory");

	return ret;
}

static __always_inline u64 __arch_get_hw_counter(s32 clock_mode,
						 const struct vdso_time_data *vd)
{
	/*
	 * Core checks for mode already, so this raced against a concurrent
	 * update. Return something. Core will do another round and then
	 * see the mode change and fallback to the syscall.
	 */
	if (clock_mode == VDSO_CLOCKMODE_NONE)
		return 0;

	return __arch_counter_get_cntvct();
}

#if IS_ENABLED(CONFIG_CC_IS_GCC) && IS_ENABLED(CONFIG_PAGE_SIZE_64KB)
static __always_inline const struct vdso_time_data *__arch_get_vdso_u_time_data(void)
{
	const struct vdso_time_data *ret = &vdso_u_time_data;

	/* Work around invalid absolute relocations */
	OPTIMIZER_HIDE_VAR(ret);

Annotation

Implementation Notes