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timekeeping: Provide a generic update_vsyscall() implementation 

The new generic VDSO library allows to unify the update_vsyscall[_tz]()
implementations.

Provide a generic implementation based on the x86 code and the bindings
which need to be implemented in architecture specific code.

[ tglx: Moved it into kernel/time where it belongs. Removed the pointless
  	line breaks in the stub functions. 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/20190621095252.32307-4-vincenzo.frascino@arm.com
This commit is contained in:
Vincenzo Frascino 2019-06-21 10:52:30 +01:00 committed by Thomas Gleixner
parent 629fdf77ac
commit 44f57d788e
4 changed files with 195 additions and 0 deletions
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50
include/asm-generic/vdso/vsyscall.h Normal file
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@ -0,0 +1,50 @@
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __ASM_GENERIC_VSYSCALL_H
#define __ASM_GENERIC_VSYSCALL_H
#ifndef __ASSEMBLY__
#ifndef __arch_get_k_vdso_data
static __always_inline struct vdso_data *__arch_get_k_vdso_data(void)
{
return NULL;
}
#endif /* __arch_get_k_vdso_data */
#ifndef __arch_update_vdso_data
static __always_inline int __arch_update_vdso_data(void)
{
return 0;
}
#endif /* __arch_update_vdso_data */
#ifndef __arch_get_clock_mode
static __always_inline int __arch_get_clock_mode(struct timekeeper *tk)
{
return 0;
}
#endif /* __arch_get_clock_mode */
#ifndef __arch_use_vsyscall
static __always_inline int __arch_use_vsyscall(struct vdso_data *vdata)
{
return 1;
}
#endif /* __arch_use_vsyscall */
#ifndef __arch_update_vsyscall
static __always_inline void __arch_update_vsyscall(struct vdso_data *vdata,
struct timekeeper *tk)
{
}
#endif /* __arch_update_vsyscall */
#ifndef __arch_sync_vdso_data
static __always_inline void __arch_sync_vdso_data(struct vdso_data *vdata)
{
}
#endif /* __arch_sync_vdso_data */
#endif /* !__ASSEMBLY__ */
#endif /* __ASM_GENERIC_VSYSCALL_H */

11
include/vdso/vsyscall.h Normal file
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@ -0,0 +1,11 @@
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __VDSO_VSYSCALL_H
#define __VDSO_VSYSCALL_H
#ifndef __ASSEMBLY__
#include <asm/vdso/vsyscall.h>
#endif /* !__ASSEMBLY__ */
#endif /* __VDSO_VSYSCALL_H */

1
kernel/time/Makefile
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@ -16,5 +16,6 @@ ifeq ($(CONFIG_GENERIC_CLOCKEVENTS_BROADCAST),y)
endif
obj-$(CONFIG_GENERIC_SCHED_CLOCK) += sched_clock.o
obj-$(CONFIG_TICK_ONESHOT) += tick-oneshot.o tick-sched.o
obj-$(CONFIG_HAVE_GENERIC_VDSO) += vsyscall.o
obj-$(CONFIG_DEBUG_FS) += timekeeping_debug.o
obj-$(CONFIG_TEST_UDELAY) += test_udelay.o

133
kernel/time/vsyscall.c Normal file
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@ -0,0 +1,133 @@
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright 2019 ARM Ltd.
*
* Generic implementation of update_vsyscall and update_vsyscall_tz.
*
* Based on the x86 specific implementation.
*/
#include <linux/hrtimer.h>
#include <linux/timekeeper_internal.h>
#include <vdso/datapage.h>
#include <vdso/helpers.h>
#include <vdso/vsyscall.h>
static inline void update_vdso_data(struct vdso_data *vdata,
struct timekeeper *tk)
{
struct vdso_timestamp *vdso_ts;
u64 nsec;
vdata[CS_HRES_COARSE].cycle_last = tk->tkr_mono.cycle_last;
vdata[CS_HRES_COARSE].mask = tk->tkr_mono.mask;
vdata[CS_HRES_COARSE].mult = tk->tkr_mono.mult;
vdata[CS_HRES_COARSE].shift = tk->tkr_mono.shift;
vdata[CS_RAW].cycle_last = tk->tkr_raw.cycle_last;
vdata[CS_RAW].mask = tk->tkr_raw.mask;
vdata[CS_RAW].mult = tk->tkr_raw.mult;
vdata[CS_RAW].shift = tk->tkr_raw.shift;
/* CLOCK_REALTIME */
vdso_ts = &vdata[CS_HRES_COARSE].basetime[CLOCK_REALTIME];
vdso_ts->sec = tk->xtime_sec;
vdso_ts->nsec = tk->tkr_mono.xtime_nsec;
/* CLOCK_MONOTONIC */
vdso_ts = &vdata[CS_HRES_COARSE].basetime[CLOCK_MONOTONIC];
vdso_ts->sec = tk->xtime_sec + tk->wall_to_monotonic.tv_sec;
nsec = tk->tkr_mono.xtime_nsec;
nsec += ((u64)tk->wall_to_monotonic.tv_nsec << tk->tkr_mono.shift);
while (nsec >= (((u64)NSEC_PER_SEC) << tk->tkr_mono.shift)) {
nsec -= (((u64)NSEC_PER_SEC) << tk->tkr_mono.shift);
vdso_ts->sec++;
}
vdso_ts->nsec = nsec;
/* CLOCK_MONOTONIC_RAW */
vdso_ts = &vdata[CS_RAW].basetime[CLOCK_MONOTONIC_RAW];
vdso_ts->sec = tk->raw_sec;
vdso_ts->nsec = tk->tkr_raw.xtime_nsec;
/* CLOCK_BOOTTIME */
vdso_ts = &vdata[CS_HRES_COARSE].basetime[CLOCK_BOOTTIME];
vdso_ts->sec = tk->xtime_sec + tk->wall_to_monotonic.tv_sec;
nsec = tk->tkr_mono.xtime_nsec;
nsec += ((u64)(tk->wall_to_monotonic.tv_nsec +
ktime_to_ns(tk->offs_boot)) << tk->tkr_mono.shift);
while (nsec >= (((u64)NSEC_PER_SEC) << tk->tkr_mono.shift)) {
nsec -= (((u64)NSEC_PER_SEC) << tk->tkr_mono.shift);
vdso_ts->sec++;
}
vdso_ts->nsec = nsec;
/* CLOCK_TAI */
vdso_ts = &vdata[CS_HRES_COARSE].basetime[CLOCK_TAI];
vdso_ts->sec = tk->xtime_sec + (s64)tk->tai_offset;
vdso_ts->nsec = tk->tkr_mono.xtime_nsec;
/*
* Read without the seqlock held by clock_getres().
* Note: No need to have a second copy.
*/
WRITE_ONCE(vdata[CS_HRES_COARSE].hrtimer_res, hrtimer_resolution);
}
void update_vsyscall(struct timekeeper *tk)
{
struct vdso_data *vdata = __arch_get_k_vdso_data();
struct vdso_timestamp *vdso_ts;
u64 nsec;
if (__arch_update_vdso_data()) {
/*
* Some architectures might want to skip the update of the
* data page.
*/
return;
}
/* copy vsyscall data */
vdso_write_begin(vdata);
vdata[CS_HRES_COARSE].clock_mode = __arch_get_clock_mode(tk);
vdata[CS_RAW].clock_mode = __arch_get_clock_mode(tk);
/* CLOCK_REALTIME_COARSE */
vdso_ts = &vdata[CS_HRES_COARSE].basetime[CLOCK_REALTIME_COARSE];
vdso_ts->sec = tk->xtime_sec;
vdso_ts->nsec = tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift;
/* CLOCK_MONOTONIC_COARSE */
vdso_ts = &vdata[CS_HRES_COARSE].basetime[CLOCK_MONOTONIC_COARSE];
vdso_ts->sec = tk->xtime_sec + tk->wall_to_monotonic.tv_sec;
nsec = tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift;
nsec = nsec + tk->wall_to_monotonic.tv_nsec;
while (nsec >= NSEC_PER_SEC) {
nsec = nsec - NSEC_PER_SEC;
vdso_ts->sec++;
}
vdso_ts->nsec = nsec;
if (__arch_use_vsyscall(vdata))
update_vdso_data(vdata, tk);
__arch_update_vsyscall(vdata, tk);
vdso_write_end(vdata);
__arch_sync_vdso_data(vdata);
}
void update_vsyscall_tz(void)
{
struct vdso_data *vdata = __arch_get_k_vdso_data();
if (__arch_use_vsyscall(vdata)) {
vdata[CS_HRES_COARSE].tz_minuteswest = sys_tz.tz_minuteswest;
vdata[CS_HRES_COARSE].tz_dsttime = sys_tz.tz_dsttime;
}
__arch_sync_vdso_data(vdata);
}