[glibc] linux: Remove supports_time64 () from clock_gettime

[glibc] linux: Remove supports_time64 () from clock_gettime

[Adhemerval Zanella]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=4ad8b4645c0869431dba632c3ace0061cc613379

commit 4ad8b4645c0869431dba632c3ace0061cc613379
Author: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Date:   Tue Jun 15 22:10:26 2021 -0300

    linux: Remove supports_time64 () from clock_gettime
    
    It breaks the usage case of live migration like CRIU or similar.
    The performance drawback is it would require an extra syscall
    on older kernels without 64-bit time support.
    
    Checked on i686-linux-gnu on a 4.15 kernel and on a 5.11 kernel
    (with and without --enable-kernel=5.1) and on x86_64-linux-gnu.
    
    Reviewed-by: Lukasz Majewski <lukma@denx.de>

Diff:
---
 sysdeps/unix/sysv/linux/clock_gettime.c | 14 ++++----------
 1 file changed, 4 insertions(+), 10 deletions(-)

diff --git a/sysdeps/unix/sysv/linux/clock_gettime.c b/sysdeps/unix/sysv/linux/clock_gettime.c
index 781d05c2fd..cfe9370455 100644
--- a/sysdeps/unix/sysv/linux/clock_gettime.c
+++ b/sysdeps/unix/sysv/linux/clock_gettime.c
@@ -22,7 +22,6 @@
 #include <time.h>
 #include "kernel-posix-cpu-timers.h"
 #include <sysdep-vdso.h>
-#include <time64-support.h>
 #include <shlib-compat.h>
 
 /* Get current value of CLOCK and store it in TP.  */
@@ -35,19 +34,14 @@ __clock_gettime64 (clockid_t clock_id, struct __timespec64 *tp)
 # define __NR_clock_gettime64 __NR_clock_gettime
 #endif
 
-  if (supports_time64 ())
-    {
 #ifdef HAVE_CLOCK_GETTIME64_VSYSCALL
-      r = INLINE_VSYSCALL (clock_gettime64, 2, clock_id, tp);
+  r = INLINE_VSYSCALL (clock_gettime64, 2, clock_id, tp);
 #else
-      r = INLINE_SYSCALL_CALL (clock_gettime64, clock_id, tp);
+  r = INLINE_SYSCALL_CALL (clock_gettime64, clock_id, tp);
 #endif
 
-      if (r == 0 || errno != ENOSYS)
-	return r;
-
-      mark_time64_unsupported ();
-   }
+  if (r == 0 || errno != ENOSYS)
+    return r;
 
 #ifndef __ASSUME_TIME64_SYSCALLS
   /* Fallback code that uses 32-bit support.  */