WARNING: 'upto' may be misspelled - perhaps 'up to'?
#12: 
value, allowing an overshoot by upto the event-stream period.
                                ^^^^

CHECK: extern prototypes should be avoided in .h files
#47: FILE: arch/arm64/include/asm/barrier.h:224:
+extern bool arch_timer_evtstrm_available(void);

WARNING: Argument 'timeout_ns' is not used in function-like macro
#59: FILE: arch/arm64/include/asm/barrier.h:236:
+#define cpu_poll_relax(ptr, val, timeout_ns) do {			\
+	if (arch_timer_evtstrm_available())				\
+		__cmpwait_relaxed(ptr, val);				\
+	else								\
+		cpu_relax();						\
+} while (0)

total: 0 errors, 2 warnings, 1 checks, 33 lines checked

NOTE: For some of the reported defects, checkpatch may be able to
      mechanically convert to the typical style using --fix or --fix-inplace.

Commit 73d2b22c57a4 ("arm64: barrier: Support smp_cond_load_relaxed_timeout()") has style problems, please review.

NOTE: Ignored message types: ALLOC_SIZEOF_STRUCT BAD_REPORTED_BY_LINK CAMELCASE COMMIT_LOG_LONG_LINE FILE_PATH_CHANGES GIT_COMMIT_ID MACRO_ARG_REUSE NO_AUTHOR_SIGN_OFF

NOTE: If any of the errors are false positives, please report
      them to the maintainer, see CHECKPATCH in MAINTAINERS.
total: 0 errors, 2 warnings, 1 checks, 33 lines checked