forked from Minki/linux
361f8aee9b
Define a common formet for the vdso datapage as a preparation for sharing the VDSO implementation as a generic library. The datastructures are based on the current x86 layout. [ tglx: Massaged changelog ] Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Shijith Thotton <sthotton@marvell.com> Tested-by: Andre Przywara <andre.przywara@arm.com> Cc: linux-arch@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-mips@vger.kernel.org Cc: linux-kselftest@vger.kernel.org Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Russell King <linux@armlinux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Burton <paul.burton@mips.com> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Mark Salyzyn <salyzyn@android.com> Cc: Peter Collingbourne <pcc@google.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Dmitry Safonov <0x7f454c46@gmail.com> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Huw Davies <huw@codeweavers.com> Link: https://lkml.kernel.org/r/20190621095252.32307-2-vincenzo.frascino@arm.com
94 lines
2.4 KiB
C
94 lines
2.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __VDSO_DATAPAGE_H
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#define __VDSO_DATAPAGE_H
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#ifdef __KERNEL__
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#ifndef __ASSEMBLY__
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#include <linux/bits.h>
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#include <linux/time.h>
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#include <linux/types.h>
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#define VDSO_BASES (CLOCK_TAI + 1)
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#define VDSO_HRES (BIT(CLOCK_REALTIME) | \
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BIT(CLOCK_MONOTONIC) | \
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BIT(CLOCK_BOOTTIME) | \
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BIT(CLOCK_TAI))
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#define VDSO_COARSE (BIT(CLOCK_REALTIME_COARSE) | \
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BIT(CLOCK_MONOTONIC_COARSE))
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#define VDSO_RAW (BIT(CLOCK_MONOTONIC_RAW))
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#define CS_HRES_COARSE 0
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#define CS_RAW 1
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#define CS_BASES (CS_RAW + 1)
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/**
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* struct vdso_timestamp - basetime per clock_id
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* @sec: seconds
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* @nsec: nanoseconds
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*
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* There is one vdso_timestamp object in vvar for each vDSO-accelerated
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* clock_id. For high-resolution clocks, this encodes the time
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* corresponding to vdso_data.cycle_last. For coarse clocks this encodes
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* the actual time.
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*
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* To be noticed that for highres clocks nsec is left-shifted by
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* vdso_data.cs[x].shift.
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*/
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struct vdso_timestamp {
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u64 sec;
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u64 nsec;
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};
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/**
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* struct vdso_data - vdso datapage representation
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* @seq: timebase sequence counter
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* @clock_mode: clock mode
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* @cycle_last: timebase at clocksource init
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* @mask: clocksource mask
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* @mult: clocksource multiplier
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* @shift: clocksource shift
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* @basetime[clock_id]: basetime per clock_id
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* @tz_minuteswest: minutes west of Greenwich
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* @tz_dsttime: type of DST correction
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* @hrtimer_res: hrtimer resolution
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* @__unused: unused
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*
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* vdso_data will be accessed by 64 bit and compat code at the same time
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* so we should be careful before modifying this structure.
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*/
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struct vdso_data {
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u32 seq;
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s32 clock_mode;
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u64 cycle_last;
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u64 mask;
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u32 mult;
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u32 shift;
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struct vdso_timestamp basetime[VDSO_BASES];
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s32 tz_minuteswest;
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s32 tz_dsttime;
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u32 hrtimer_res;
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u32 __unused;
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};
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/*
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* We use the hidden visibility to prevent the compiler from generating a GOT
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* relocation. Not only is going through a GOT useless (the entry couldn't and
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* must not be overridden by another library), it does not even work: the linker
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* cannot generate an absolute address to the data page.
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*
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* With the hidden visibility, the compiler simply generates a PC-relative
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* relocation, and this is what we need.
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*/
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extern struct vdso_data _vdso_data[CS_BASES] __attribute__((visibility("hidden")));
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#endif /* !__ASSEMBLY__ */
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#endif /* __KERNEL__ */
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#endif /* __VDSO_DATAPAGE_H */
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