Fixed time processing.

- arm64: Get TSC corresponding to boot time from IHK.

- x86_64: Calculate the current time using vdso.

Refs: #1186
Fujitsu: POSTK_DEBUG_ARCH_DEP_52
Change-Id: I293ba4bbe5390d50dea44b8a5b7471f59237daff

arch/arm64/kernel/syscall.c

@@ -2699,4 +2699,40 @@ SYSCALL_DECLARE(time)
 	return time();
 }
 
+void calculate_time_from_tsc(struct timespec *ts)
+{
+	long ver;
+	unsigned long current_tsc;
+	time_t sec_delta;
+	long ns_delta;
+
+	for (;;) {
+		while ((ver = ihk_atomic64_read(&tod_data.version)) & 1) {
+			/* settimeofday() is in progress */
+			cpu_pause();
+		}
+		rmb(); /* fetch version before time */
+		*ts = tod_data.origin;
+		rmb(); /* fetch time before checking version */
+		if (ver == ihk_atomic64_read(&tod_data.version)) {
+			break;
+		}
+
+		/* settimeofday() has intervened */
+		cpu_pause();
+	}
+
+	current_tsc = rdtsc();
+	sec_delta = current_tsc / tod_data.clocks_per_sec;
+	ns_delta = NS_PER_SEC * (current_tsc % tod_data.clocks_per_sec)
+		/ tod_data.clocks_per_sec;
+	/* calc. of ns_delta overflows if clocks_per_sec exceeds 18.44 GHz */
+
+	ts->tv_sec += sec_delta;
+	ts->tv_nsec += ns_delta;
+	if (ts->tv_nsec >= NS_PER_SEC) {
+		ts->tv_nsec -= NS_PER_SEC;
+		++ts->tv_sec;
+	}
+}
 /*** End of File ***/

arch/arm64/kernel/vdso.c

@@ -23,7 +23,6 @@
 #define DDEBUG_DEFAULT DDEBUG_PRINT
 #endif
 
-#ifdef POSTK_DEBUG_ARCH_DEP_52
 #define VDSO_MAXPAGES 1
 struct vdso {
 	long busy;
@@ -34,7 +33,6 @@ struct vdso {
 	long lbase;
 	long offset_sigtramp;
 };
-#endif /*POSTK_DEBUG_ARCH_DEP_52*/
 
 extern char vdso_start, vdso_end;
 static struct vdso vdso;

arch/x86_64/kernel/syscall.c

@@ -64,7 +64,6 @@ uintptr_t debug_constants[] = {
 	-1,
 };
 
-#ifdef POSTK_DEBUG_ARCH_DEP_52
 #define VDSO_MAXPAGES 2
 struct vdso {
 	long busy;
@@ -80,8 +79,24 @@ struct vdso {
 	long hpet_phys;
 	void *pvti_virt;
 	long pvti_phys;
+	void *vgtod_virt;
+};
+
+struct vsyscall_gtod_data {
+	int seq;
+
+	struct {
+		int vclock_mode;
+		unsigned long cycle_last;
+		unsigned long mask;
+		unsigned int mult;
+		unsigned int shift;
+	} clock;
+
+	/* open coded 'struct timespec' */
+	time_t wall_time_sec;
+	unsigned long wall_time_snsec;
 };
-#endif /*POSTK_DEBUG_ARCH_DEP_52*/
 
 static struct vdso vdso;
 static size_t container_size = 0;
@@ -2811,4 +2826,37 @@ time_t time(void) {
 	return ret;
 }
 
+void calculate_time_from_tsc(struct timespec *ts)
+{
+	unsigned long seq;
+	unsigned long seq2;
+	unsigned long ns;
+	unsigned long delta;
+	struct vsyscall_gtod_data *gtod = vdso.vgtod_virt;
+
+	do {
+		for (;;) {
+			seq = ACCESS_ONCE(gtod->seq);
+			if (unlikely(seq & 1)) {
+				cpu_pause();
+				continue;
+			}
+			break;
+		}
+		rmb(); /* fetch sequence before time */
+		ts->tv_sec = gtod->wall_time_sec;
+		ns = gtod->wall_time_snsec;
+		delta = rdtsc() - gtod->clock.cycle_last;
+		ns += delta * gtod->clock.mult;
+		ns >>= gtod->clock.shift;
+		seq2 = ACCESS_ONCE(gtod->seq);
+		rmb(); /* fetch time before checking sequence */
+	} while (seq != seq2);
+	ts->tv_nsec = ns;
+
+	if (ts->tv_nsec >= NS_PER_SEC) {
+		ts->tv_nsec -= NS_PER_SEC;
+		++ts->tv_sec;
+	}
+}
 /*** End of File ***/