[Xen-devel] [RFC PATCH v2 09/11] time: Convert pvclock_read_wallclock() to use timespec64

["pang.xunlei" <pang.xunlei@xxxxxxxxxx>]

As part of addressing 2038 safety for in-kernel uses, this patch
creates no functional change, converts pvclock_read_wallclock()
to use timespec64 instead of timespec.

Signed-off-by: pang.xunlei <pang.xunlei@xxxxxxxxxx>
---
 arch/x86/include/asm/pvclock.h |    2 +-
 arch/x86/kernel/kvmclock.c     |    7 +++++--
 arch/x86/kernel/pvclock.c      |    9 +++++----
 arch/x86/xen/time.c            |    7 ++-----
 4 files changed, 13 insertions(+), 12 deletions(-)

diff --git a/arch/x86/include/asm/pvclock.h b/arch/x86/include/asm/pvclock.h
index d6b078e..3323413 100644
--- a/arch/x86/include/asm/pvclock.h
+++ b/arch/x86/include/asm/pvclock.h
@@ -11,7 +11,7 @@ void pvclock_set_flags(u8 flags);
 unsigned long pvclock_tsc_khz(struct pvclock_vcpu_time_info *src);
 void pvclock_read_wallclock(struct pvclock_wall_clock *wall,
                            struct pvclock_vcpu_time_info *vcpu,
-                           struct timespec *ts);
+                           struct timespec64 *ts);
 void pvclock_resume(void);
 
 void pvclock_touch_watchdogs(void);
diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c
index d9156ce..7cd3511 100644
--- a/arch/x86/kernel/kvmclock.c
+++ b/arch/x86/kernel/kvmclock.c
@@ -46,10 +46,12 @@ static struct pvclock_wall_clock wall_clock;
 /*
  * The wallclock is the time of day when we booted. Since then, some time may
  * have elapsed since the hypervisor wrote the data. So we try to account for
- * that with system time
+ * that with system time.
+ * TODO: [2038 safety] kvm_get_wallclock() should be fixed to use timespec64.
  */
 static void kvm_get_wallclock(struct timespec *now)
 {
+       struct timespec64 now64;
        struct pvclock_vcpu_time_info *vcpu_time;
        int low, high;
        int cpu;
@@ -63,7 +65,8 @@ static void kvm_get_wallclock(struct timespec *now)
        cpu = smp_processor_id();
 
        vcpu_time = &hv_clock[cpu].pvti;
-       pvclock_read_wallclock(&wall_clock, vcpu_time, now);
+       pvclock_read_wallclock(&wall_clock, vcpu_time, &now64);
+       *now = timespec64_to_timespec(now64);
 
        preempt_enable();
 }
diff --git a/arch/x86/kernel/pvclock.c b/arch/x86/kernel/pvclock.c
index 2f355d2..8e9bbe9 100644
--- a/arch/x86/kernel/pvclock.c
+++ b/arch/x86/kernel/pvclock.c
@@ -117,17 +117,18 @@ cycle_t 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 */
-               now.tv_sec  = wall_clock->sec;
+               /* TODO: [2038 safety] wall_clock->sec uses time64_t */
+               now.tv_sec  = (time64_t)wall_clock->sec;
                now.tv_nsec = wall_clock->nsec;
                rmb();          /* fetch time before checking version */
        } while ((wall_clock->version & 1) || (version != wall_clock->version));
@@ -138,7 +139,7 @@ void pvclock_read_wallclock(struct pvclock_wall_clock 
*wall_clock,
        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);
 }
 
 #ifdef CONFIG_X86_64
diff --git a/arch/x86/xen/time.c b/arch/x86/xen/time.c
index 4e14439..79053ee 100644
--- a/arch/x86/xen/time.c
+++ b/arch/x86/xen/time.c
@@ -171,15 +171,12 @@ static cycle_t xen_clocksource_get_cycles(struct 
clocksource *cs)
 
 static void xen_read_wallclock(struct timespec64 *ts)
 {
-       struct timespec ts_unsafe;
        struct shared_info *s = HYPERVISOR_shared_info;
        struct pvclock_wall_clock *wall_clock = &(s->wc);
-        struct pvclock_vcpu_time_info *vcpu_time;
+       struct pvclock_vcpu_time_info *vcpu_time;
 
        vcpu_time = &get_cpu_var(xen_vcpu)->time;
-       /* TODO: [2038 safety] pvclock_read_wallclock() uses timespec64 */
-       pvclock_read_wallclock(wall_clock, vcpu_time, &ts_unsafe);
-       *ts = timespec_to_timespec64(ts_unsafe);
+       pvclock_read_wallclock(wall_clock, vcpu_time, ts);
        put_cpu_var(xen_vcpu);
 }
 
-- 
1.7.9.5


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