!772 timekeeping: Make CLOCKSOURCE_VALIDATE_LAST_CYCLE configurable

Merge Pull Request from: @liaoyu15 
 
Currently, only x86 architecture supports the CLOCKSOURCE_VALIDATE_LAST_CYCLE
option. This option ensures that the timestamps returned by the clocksource are
monotonically increasing, and helps avoid issues caused by hardware failures.

This commit makes CLOCKSOURCE_VALIDATE_LAST_CYCLE configurable on
the arm64 architecture, helps increase system stability and reliability. 
 
Link:https://gitee.com/openeuler/kernel/pulls/772 

Reviewed-by: Jialin Zhang <zhangjialin11@huawei.com> 
Reviewed-by: Wei Li <liwei391@huawei.com> 
Reviewed-by: Liu Chao <liuchao173@huawei.com> 
Signed-off-by: Jialin Zhang <zhangjialin11@huawei.com> 

arch/arm64/configs/openeuler_defconfig

@@ -69,6 +69,7 @@ CONFIG_CONTEXT_TRACKING=y
 # CONFIG_CONTEXT_TRACKING_FORCE is not set
 CONFIG_NO_HZ=y
 CONFIG_HIGH_RES_TIMERS=y
+# CONFIG_CLOCKSOURCE_VALIDATE_LAST_CYCLE is not set
 # end of Timers subsystem
 
 CONFIG_PREEMPT_NONE=y

kernel/time/Kconfig

@@ -17,11 +17,6 @@ config ARCH_CLOCKSOURCE_DATA
 config ARCH_CLOCKSOURCE_INIT
 	bool
 
-# Clocksources require validation of the clocksource against the last
-# cycle update - x86/TSC misfeature
-config CLOCKSOURCE_VALIDATE_LAST_CYCLE
-	bool
-
 # Timekeeping vsyscall support
 config GENERIC_TIME_VSYSCALL
 	bool
@@ -173,5 +168,13 @@ config HIGH_RES_TIMERS
 	  hardware is not capable then this option only increases
 	  the size of the kernel image.
 
+# Clocksources require validation of the clocksource against the last
+# cycle update - x86/TSC misfeature
+config CLOCKSOURCE_VALIDATE_LAST_CYCLE
+	bool "Validate last cycle of clocksource"
+	help
+	  Enable this option to validate the last cycle to prevent issues
+	  caused by clocksource going backwards.
+
 endmenu
 endif