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- /* SPDX-License-Identifier: GPL-2.0 */
- #ifndef __VDSO_DATAPAGE_H
- #define __VDSO_DATAPAGE_H
- #ifndef __ASSEMBLY__
- #include <linux/compiler.h>
- #include <uapi/linux/time.h>
- #include <uapi/linux/types.h>
- #include <uapi/asm-generic/errno-base.h>
- #include <vdso/bits.h>
- #include <vdso/clocksource.h>
- #include <vdso/ktime.h>
- #include <vdso/limits.h>
- #include <vdso/math64.h>
- #include <vdso/processor.h>
- #include <vdso/time.h>
- #include <vdso/time32.h>
- #include <vdso/time64.h>
- #ifdef CONFIG_ARCH_HAS_VDSO_DATA
- #include <asm/vdso/data.h>
- #else
- struct arch_vdso_data {};
- #endif
- #define VDSO_BASES (CLOCK_TAI + 1)
- #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 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_data.cycle_last. For coarse clocks this encodes
- * the actual time.
- *
- * To be noticed that for highres clocks nsec is left-shifted by
- * vdso_data.cs[x].shift.
- */
- struct vdso_timestamp {
- u64 sec;
- u64 nsec;
- };
- /**
- * struct vdso_data - vdso datapage representation
- * @seq: timebase sequence counter
- * @clock_mode: clock mode
- * @cycle_last: timebase at clocksource init
- * @mask: clocksource mask
- * @mult: clocksource multiplier
- * @shift: clocksource shift
- * @basetime[clock_id]: basetime per clock_id
- * @offset[clock_id]: time namespace offset per clock_id
- * @tz_minuteswest: minutes west of Greenwich
- * @tz_dsttime: type of DST correction
- * @hrtimer_res: hrtimer resolution
- * @__unused: unused
- * @arch_data: architecture specific data (optional, defaults
- * to an empty struct)
- *
- * vdso_data will be accessed by 64 bit and compat code at the same time
- * so we should be careful before modifying this structure.
- *
- * @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_data {
- u32 seq;
- s32 clock_mode;
- u64 cycle_last;
- u64 mask;
- u32 mult;
- u32 shift;
- union {
- struct vdso_timestamp basetime[VDSO_BASES];
- struct timens_offset offset[VDSO_BASES];
- };
- s32 tz_minuteswest;
- s32 tz_dsttime;
- u32 hrtimer_res;
- u32 __unused;
- struct arch_vdso_data arch_data;
- };
- /*
- * We use the hidden visibility to prevent the compiler from generating a GOT
- * relocation. Not only is going through a GOT useless (the entry couldn't and
- * must not be overridden by another library), it does not even work: the linker
- * cannot generate an absolute address to the data page.
- *
- * With the hidden visibility, the compiler simply generates a PC-relative
- * relocation, and this is what we need.
- */
- extern struct vdso_data _vdso_data[CS_BASES] __attribute__((visibility("hidden")));
- extern struct vdso_data _timens_data[CS_BASES] __attribute__((visibility("hidden")));
- /*
- * The generic vDSO implementation requires that gettimeofday.h
- * provides:
- * - __arch_get_vdso_data(): to get the vdso datapage.
- * - __arch_get_hw_counter(): to get the hw counter based on the
- * clock_mode.
- * - gettimeofday_fallback(): fallback for gettimeofday.
- * - clock_gettime_fallback(): fallback for clock_gettime.
- * - clock_getres_fallback(): fallback for clock_getres.
- */
- #ifdef ENABLE_COMPAT_VDSO
- #include <asm/vdso/compat_gettimeofday.h>
- #else
- #include <asm/vdso/gettimeofday.h>
- #endif /* ENABLE_COMPAT_VDSO */
- #endif /* !__ASSEMBLY__ */
- #endif /* __VDSO_DATAPAGE_H */
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