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x86/vdso: Switch to generic vDSO implementation

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The x86 vDSO library requires some adaptations to take advantage of the
newly introduced generic vDSO library.

Introduce the following changes:
 - Modification of vdso.c to be compliant with the common vdso datapage
 - Use of lib/vdso for gettimeofday

[ tglx: Massaged changelog and cleaned up the function signature formatting ]

Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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>
Cc: Shijith Thotton <sthotton@marvell.com>
Cc: Andre Przywara <andre.przywara@arm.com>
Link: https://lkml.kernel.org/r/20190621095252.32307-23-vincenzo.frascino@arm.com
This commit is contained in:
Vincenzo Frascino
2019-06-21 10:52:49 +01:00
committed by Thomas Gleixner
parent bfe801ebe8
commit 7ac8707479
12 changed files with 297 additions and 392 deletions
Download Patch File Download Diff File Expand all files Collapse all files

75
arch/x86/include/asm/vgtod.h
View File

@@ -3,7 +3,9 @@
#define _ASM_X86_VGTOD_H
#include <linux/compiler.h>
#include <linux/clocksource.h>
#include <asm/clocksource.h>
#include <vdso/datapage.h>
#include <vdso/helpers.h>
#include <uapi/linux/time.h>
@@ -13,81 +15,10 @@ typedef u64 gtod_long_t;
typedef unsigned long gtod_long_t;
#endif
/*
* There is one of these objects in the vvar page for each
* vDSO-accelerated clockid. For high-resolution clocks, this encodes
* the time corresponding to vsyscall_gtod_data.cycle_last. For coarse
* clocks, this encodes the actual time.
*
* To confuse the reader, for high-resolution clocks, nsec is left-shifted
* by vsyscall_gtod_data.shift.
*/
struct vgtod_ts {
u64 sec;
u64 nsec;
};
#define VGTOD_BASES (CLOCK_TAI + 1)
#define VGTOD_HRES (BIT(CLOCK_REALTIME) | BIT(CLOCK_MONOTONIC) | BIT(CLOCK_TAI))
#define VGTOD_COARSE (BIT(CLOCK_REALTIME_COARSE) | BIT(CLOCK_MONOTONIC_COARSE))
/*
* vsyscall_gtod_data will be accessed by 32 and 64 bit code at the same time
* so be carefull by modifying this structure.
*/
struct vsyscall_gtod_data {
unsigned int seq;
int vclock_mode;
u64 cycle_last;
u64 mask;
u32 mult;
u32 shift;
struct vgtod_ts basetime[VGTOD_BASES];
int tz_minuteswest;
int tz_dsttime;
};
extern struct vsyscall_gtod_data vsyscall_gtod_data;
extern int vclocks_used;
static inline bool vclock_was_used(int vclock)
{
return READ_ONCE(vclocks_used) & (1 << vclock);
}
static inline unsigned int gtod_read_begin(const struct vsyscall_gtod_data *s)
{
unsigned int ret;
repeat:
ret = READ_ONCE(s->seq);
if (unlikely(ret & 1)) {
cpu_relax();
goto repeat;
}
smp_rmb();
return ret;
}
static inline int gtod_read_retry(const struct vsyscall_gtod_data *s,
unsigned int start)
{
smp_rmb();
return unlikely(s->seq != start);
}
static inline void gtod_write_begin(struct vsyscall_gtod_data *s)
{
++s->seq;
smp_wmb();
}
static inline void gtod_write_end(struct vsyscall_gtod_data *s)
{
smp_wmb();
++s->seq;
}
#endif /* _ASM_X86_VGTOD_H */