clocksource: arch_timer: make virtual counter access configurable

Bug: 68266545
Change-Id: Ibdb1fd768b748002b90bfc165612c12c8311f8a2
Signed-off-by: Swetha Chikkaboraiah <schikk@codeaurora.org>
Signed-off-by: Satyanarayana Dash <sadash@codeaurora.org>

drivers/clocksource/Kconfig

@@ -82,6 +82,14 @@ config ARM_ARCH_TIMER_EVTSTREAM
 	  This must be disabled for hardware validation purposes to detect any
 	  hardware anomalies of missing events.
 
+config ARM_ARCH_TIMER_VCT_ACCESS
+	bool "Support for ARM architected timer virtual counter access in userspace"
+	default !ARM64
+	depends on ARM_ARCH_TIMER
+	help
+	  This option enables support for reading the ARM architected timer's
+	  virtual counter in userspace.
+
 config CLKSRC_METAG_GENERIC
 	def_bool y if METAG
 	help

drivers/clocksource/arm_arch_timer.c

@@ -320,7 +320,11 @@ static void arch_counter_set_user_access(void)
 			| ARCH_TIMER_VIRT_EVT_EN);
 
 	/* Enable user access to the virtual and physical counters */
-	cntkctl |= ARCH_TIMER_USR_VCT_ACCESS_EN | ARCH_TIMER_USR_PCT_ACCESS_EN;
+	cntkctl |= ARCH_TIMER_USR_PCT_ACCESS_EN;
+	if (IS_ENABLED(CONFIG_ARM_ARCH_TIMER_VCT_ACCESS))
+		cntkctl |= ARCH_TIMER_USR_VCT_ACCESS_EN;
+	else
+		cntkctl &= ~ARCH_TIMER_USR_VCT_ACCESS_EN;
 
 	arch_timer_set_cntkctl(cntkctl);
 }