x86: Convert x86_platform_ops to timespec64

The x86 platform operations are fairly isolated, so it's easy to change
them from using timespec to timespec64. It has been checked that all the
users and callers are safe, and there is only one critical function that is
broken beyond 2106:

  pvclock_read_wallclock() uses a 32-bit number of seconds since the epoch
  to communicate the boot time between host and guest in a virtual
  environment. This will work until 2106, but fixing this is outside the
  scope of this change, Add a comment at least.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Acked-by: Radim Krčmář <rkrcmar@redhat.com>
Acked-by: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: jailhouse-dev@googlegroups.com
Cc: Borislav Petkov <bp@suse.de>
Cc: kvm@vger.kernel.org
Cc: y2038@lists.linaro.org
Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Cc: xen-devel@lists.xenproject.org
Cc: John Stultz <john.stultz@linaro.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Joao Martins <joao.m.martins@oracle.com>
Link: https://lkml.kernel.org/r/20180427201435.3194219-1-arnd@arndb.de

1 files changed, 11 insertions, 4 deletions

diff --git a/arch/x86/kernel/pvclock.c b/arch/x86/kernel/pvclock.c
index 761f6af6efa5..637982efecd8 100644
--- a/arch/x86/kernel/pvclock.c
+++ b/arch/x86/kernel/pvclock.c
@@ -123,28 +123,35 @@ u64 pvclock_clocksource_read(struct pvclock_vcpu_time_info *src)
 
 void pvclock_read_wallclock(struct pvclock_wall_clock *wall_clock,
 			    struct pvclock_vcpu_time_info *vcpu_time,
-			    struct timespec *ts)
+			    struct timespec64 *ts)
 {
 	u32 version;
 	u64 delta;
-	struct timespec now;
+	struct timespec64 now;
 
 	/* get wallclock at system boot */
 	do {
 		version = wall_clock->version;
 		rmb();		/* fetch version before time */
+		/*
+		 * Note: wall_clock->sec is a u32 value, so it can
+		 * only store dates between 1970 and 2106. To allow
+		 * times beyond that, we need to create a new hypercall
+		 * interface with an extended pvclock_wall_clock structure
+		 * like ARM has.
+		 */
 		now.tv_sec  = wall_clock->sec;
 		now.tv_nsec = wall_clock->nsec;
 		rmb();		/* fetch time before checking version */
 	} while ((wall_clock->version & 1) || (version != wall_clock->version));
 
 	delta = pvclock_clocksource_read(vcpu_time);	/* time since system boot */
-	delta += now.tv_sec * (u64)NSEC_PER_SEC + now.tv_nsec;
+	delta += now.tv_sec * NSEC_PER_SEC + now.tv_nsec;
 
 	now.tv_nsec = do_div(delta, NSEC_PER_SEC);
 	now.tv_sec = delta;
 
-	set_normalized_timespec(ts, now.tv_sec, now.tv_nsec);
+	set_normalized_timespec64(ts, now.tv_sec, now.tv_nsec);
 }
 
 void pvclock_set_pvti_cpu0_va(struct pvclock_vsyscall_time_info *pvti)