UPSTREAM: x86/vdso: Add clock_gettime64() entry point

Linux 5.1 gained the new clock_gettime64() syscall to address the Y2038
problem on 32bit systems. The x86 VDSO is missing support for this variant
of clock_gettime().

Update the x86 specific vDSO library accordingly so it exposes the new time
getter.

[ tglx: Massaged changelog ]

Signed-off-by: Vincenzo Frascino <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: Catalin Marinas <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: Russell King <[email protected]>
Cc: Ralf Baechle <[email protected]>
Cc: Paul Burton <[email protected]>
Cc: Daniel Lezcano <[email protected]>
Cc: Mark Salyzyn <[email protected]>
Cc: Peter Collingbourne <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Dmitry Safonov <[email protected]>
Cc: Rasmus Villemoes <[email protected]>
Cc: Huw Davies <[email protected]>
Cc: Shijith Thotton <[email protected]>
Cc: Andre Przywara <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
(cherry picked from commit 22ca962)
Signed-off-by: Mark Salyzyn <[email protected]>
Bug: 154668398
Change-Id: I337343fe94403d2eea20d356f0e7263285cec9a2

arch/x86/entry/vdso/vclock_gettime.c

@@ -66,6 +66,14 @@ int __vdso_clock_gettime(clockid_t clock, struct old_timespec32 *ts)
 int clock_gettime(clockid_t, struct old_timespec32 *)
 	__attribute__((weak, alias("__vdso_clock_gettime")));
 
+int __vdso_clock_gettime64(clockid_t clock, struct __kernel_timespec *ts)
+{
+	return __cvdso_clock_gettime(clock, ts);
+}
+
+int clock_gettime64(clockid_t, struct __kernel_timespec *)
+	__attribute__((weak, alias("__vdso_clock_gettime64")));
+
 int __vdso_clock_getres(clockid_t clock, struct old_timespec32 *res)
 {
 	return __cvdso_clock_getres_time32(clock, res);

arch/x86/entry/vdso/vdso32/vdso32.lds.S

@@ -27,6 +27,7 @@ VERSION
 		__vdso_gettimeofday;
 		__vdso_time;
 		__vdso_clock_getres;
+		__vdso_clock_gettime64;
 	};
 
 	LINUX_2.5 {