x86/vdso: Switch to generic vDSO implementation

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

1 files changed, 3 insertions, 72 deletions

diff --git a/arch/x86/include/asm/vgtod.h b/arch/x86/include/asm/vgtod.h
index 913a133f8e6f..a2638c6124ed 100644
--- a/arch/x86/include/asm/vgtod.h
+++ b/arch/x86/include/asm/vgtod.h
@@ -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 */