/* SPDX-License-Identifier: GPL-2.0 */ #ifndef __VDSO_DATAPAGE_H #define __VDSO_DATAPAGE_H #ifndef __ASSEMBLY__ #include <linux/bits.h> #include <linux/time.h> #include <linux/types.h> #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 * @tz_minuteswest: minutes west of Greenwich * @tz_dsttime: type of DST correction * @hrtimer_res: hrtimer resolution * @__unused: unused * * vdso_data will be accessed by 64 bit and compat code at the same time * so we should be careful before modifying this structure. */ struct vdso_data { u32 seq; s32 clock_mode; u64 cycle_last; u64 mask; u32 mult; u32 shift; struct vdso_timestamp basetime[VDSO_BASES]; s32 tz_minuteswest; s32 tz_dsttime; u32 hrtimer_res; u32 __unused; }; /* * 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"))); #endif /* !__ASSEMBLY__ */ #endif /* __VDSO_DATAPAGE_H */