los_vdso_sys.c 文件参考

浏览源代码.

函数
STATIC INT32	VdsoGetRealtimeCoarse (struct timespec *ts, const VdsoDataPage *usrVdsoDataPage)
	通过vdso获取大致的实时时间 更多...
STATIC INT32	VdsoGetMonotimeCoarse (struct timespec *ts, const VdsoDataPage *usrVdsoDataPage)
	通过vdso获取大致的运行时间 更多...
STATIC size_t	LocVdsoStart (size_t vdsoStart, const CHAR *elfHead, const size_t len)
	开始vdso 更多...
INT32	VdsoClockGettime (clockid_t clk, struct timespec *ts)

函数说明

LocVdsoStart()

STATIC size_t LocVdsoStart	(	size_t	vdsoStart,
		const CHAR *	elfHead,
		const size_t	len
	)

开始vdso

在文件 los_vdso_sys.c 第 60 行定义.

{
    CHAR *head = NULL;
    INT32 i;
    INT32 loop;
 
    for (i = 1; i <= MAX_PAGES; i++) {
        head = (CHAR *)((UINTPTR)vdsoStart);
        for (loop = len; loop >= 1; loop--) {
            if (*head++ != *(elfHead + len - loop)) {
                break;
            }
        }
        if (loop) {
            vdsoStart -= PAGE_SIZE;
        } else {
            break;
        }
    }
 
    if (i > MAX_PAGES) {
        return 0;
    }
    return (vdsoStart - PAGE_SIZE);
}

这是这个函数的调用关系图:

VdsoClockGettime()

INT32 VdsoClockGettime	(	clockid_t	clk,
		struct timespec *	ts
	)

在文件 los_vdso_sys.c 第 86 行定义.

{
    INT32 ret;
    size_t vdsoStart;
 
    __asm__ __volatile__("mov %0, pc" : "=r"(vdsoStart));
    vdsoStart = vdsoStart - (vdsoStart & (PAGE_SIZE - 1));
    vdsoStart = LocVdsoStart(vdsoStart, ELF_HEAD, ELF_HEAD_LEN);
    if (vdsoStart == 0) {
        return -1;
    }
 
    VdsoDataPage *usrVdsoDataPage = (VdsoDataPage *)(UINTPTR)vdsoStart;
 
    switch (clk) {
        case CLOCK_REALTIME_COARSE:
            ret = VdsoGetRealtimeCoarse(ts, usrVdsoDataPage);
            break;
        case CLOCK_MONOTONIC_COARSE:
            ret = VdsoGetMonotimeCoarse(ts, usrVdsoDataPage);
            break;
        default:
            ret = -1;
            break;
    }
 
    return ret;
}

函数调用图:

VdsoGetMonotimeCoarse()

STATIC INT32 VdsoGetMonotimeCoarse	(	struct timespec *	ts,
		const VdsoDataPage *	usrVdsoDataPage
	)

通过vdso获取大致的运行时间

在文件 los_vdso_sys.c 第 49 行定义.

{
    do {
        if (!usrVdsoDataPage->lockCount) {
            ts->tv_sec = usrVdsoDataPage->monoTimeSec;
            ts->tv_nsec = usrVdsoDataPage->monoTimeNsec;
            return 0;
        }
    } while (1);
}

这是这个函数的调用关系图:

VdsoGetRealtimeCoarse()

STATIC INT32 VdsoGetRealtimeCoarse	(	struct timespec *	ts,
		const VdsoDataPage *	usrVdsoDataPage
	)

通过vdso获取大致的实时时间

在文件 los_vdso_sys.c 第 38 行定义.

{
    do {
        if (!usrVdsoDataPage->lockCount) {
            ts->tv_sec = usrVdsoDataPage->realTimeSec;
            ts->tv_nsec = usrVdsoDataPage->realTimeNsec;
            return 0;
        }
    } while (1);
}

这是这个函数的调用关系图: