Index: sys/arm64/linux/linux_machdep.c
===================================================================
--- sys/arm64/linux/linux_machdep.c
+++ sys/arm64/linux/linux_machdep.c
@@ -37,6 +37,7 @@
 #include <sys/ktr.h>
 #include <sys/proc.h>
 #include <sys/sdt.h>
+#include <sys/syscallsubr.h>
 
 #include <security/audit/audit.h>
 
@@ -124,13 +125,25 @@
 	return (linux_madvise_common(td, PTROUT(uap->addr), uap->len, uap->behav));
 }
 
-/* LINUXTODO: implement arm64 linux_rt_sigsuspend */
 int
 linux_rt_sigsuspend(struct thread *td, struct linux_rt_sigsuspend_args *uap)
 {
+	l_sigset_t lmask;
+	sigset_t sigmask;
+	int error;
 
-	LIN_SDT_PROBE0(machdep, linux_rt_sigsuspend, todo);
-	return (EDOOFUS);
+	LINUX_CTR2(rt_sigsuspend, "%p, %ld",
+	    uap->newset, uap->sigsetsize);
+
+	if (uap->sigsetsize != sizeof(l_sigset_t))
+		return (EINVAL);
+
+	error = copyin(uap->newset, &lmask, sizeof(l_sigset_t));
+	if (error)
+		return (error);
+
+	linux_to_bsd_sigset(&lmask, &sigmask);
+	return (kern_sigsuspend(td, sigmask));
 }
 
 /* LINUXTODO: implement arm64 linux_sigaltstack */