Index: tests/sys/kern/Makefile
===================================================================
--- tests/sys/kern/Makefile
+++ tests/sys/kern/Makefile
@@ -9,6 +9,7 @@
 
 TESTSDIR=	${TESTSBASE}/sys/kern
 
+ATF_TESTS_C+=	basic_signal
 #ATF_TESTS_C+=	kcov
 ATF_TESTS_C+=	kern_copyin
 ATF_TESTS_C+=	kern_descrip_test
Index: tests/sys/kern/basic_signal.c
===================================================================
--- /dev/null
+++ tests/sys/kern/basic_signal.c
@@ -0,0 +1,156 @@
+/*-
+ * Copyright (c) 2021 Warner Losh <imp@bsdimp.com>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <atf-c.h>
+#include <errno.h>
+#include <signal.h>
+#include <stdbool.h>
+#include <stdlib.h>
+
+static volatile sig_atomic_t signal_fired = 0;
+
+static void
+sig_handler(int signo, siginfo_t *info __unused, void *ucp __unused)
+{
+	signal_fired++;
+}
+
+ATF_TC(signal_test);
+
+ATF_TC_HEAD(signal_test, tc)
+{
+
+	atf_tc_set_md_var(tc, "descr", "Testing delivery of a signal");
+}
+
+ATF_TC_BODY(signal_test, tc)
+{
+	/*
+	 * Setup the signal handlers
+	 */
+	struct sigaction sa = {
+		.sa_sigaction = sig_handler,
+		.sa_flags = SA_SIGINFO,
+	};
+	ATF_REQUIRE(sigemptyset(&sa.sa_mask) == 0);
+	ATF_REQUIRE(sigaction(SIGUSR1, &sa, NULL) == 0);
+	ATF_REQUIRE(sigaction(SIGUSR2, &sa, NULL) == 0);
+	ATF_REQUIRE(sigaction(SIGALRM, &sa, NULL) == 0);
+
+	/*
+	 * Fire SIGUSR1
+	 */
+	ATF_CHECK(signal_fired == 0);
+	ATF_REQUIRE(raise(SIGUSR1) == 0);
+	ATF_CHECK(signal_fired == 1);
+
+	/*
+	 * Fire SIGUSR2
+	 */
+	ATF_REQUIRE(raise(SIGUSR2) == 0);
+	ATF_CHECK(signal_fired == 2);
+
+	/*
+	 * Fire SIGALRM after a timeout
+	 */
+	ATF_REQUIRE(alarm(1) == 0);
+	ATF_REQUIRE(pause() == -1);
+	ATF_REQUIRE(errno == EINTR);
+	ATF_CHECK(signal_fired == 3);
+}
+
+/*
+ * Special tests for 32-bit arm. We can call thumb (really just t32) from normal
+ * (a32) mode and vice versa. Likewise, signals can interrupt a T32 context with
+ * A32 code and vice versa. Make sure these all work with a simple test that
+ * raises the signal and ensures that it executed. No other platform has these
+ * requirements. Also note: we only support thumb2, so there's no T16 vs T32
+ * issues we have to test for.
+ */
+#ifdef __arm__
+
+static volatile sig_atomic_t t32_fired = 0;
+static volatile sig_atomic_t a32_fired = 0;
+
+__attribute__((target("arch=arm")))
+static void
+sig_a32(int signo, siginfo_t *info __unused, void *ucp __unused)
+{
+	a32_fired++;
+}
+
+__attribute__((target("arch=thumb")))
+static void
+sig_t32(int signo, siginfo_t *info __unused, void *ucp __unused)
+{
+	t32_fired++;
+}
+
+
+ATF_TC(signal_test_T32_to_A32);
+
+ATF_TC_HEAD(signal_test_T32_to_A32, tc)
+{
+
+	atf_tc_set_md_var(tc, "descr", "Testing delivery of a signal from T32 to A32");
+}
+
+__attribute__((target("arch=thumb")))
+ATF_TC_BODY(signal_test_T32_to_A32, tc)
+{
+	/*
+	 * Setup the signal handlers
+	 */
+	struct sigaction sa = {
+		.sa_sigaction = sig_a32,
+		.sa_flags = SA_SIGINFO,
+	};
+	ATF_REQUIRE(sigemptyset(&sa.sa_mask) == 0);
+	ATF_REQUIRE(sigaction(SIGUSR1, &sa, NULL) == 0);
+
+	ATF_CHECK(a32_fired == 0);
+	ATF_REQUIRE(raise(SIGUSR1) == 0);
+	ATF_CHECK(a32_fired == 1);
+}
+
+ATF_TC(signal_test_A32_to_T32);
+
+ATF_TC_HEAD(signal_test_A32_to_T32, tc)
+{
+
+	atf_tc_set_md_var(tc, "descr", "Testing delivery of a signal from A32 to T32");
+}
+
+__attribute__((target("arch=arm")))
+ATF_TC_BODY(signal_test_A32_to_T32, tc)
+{
+	/*
+	 * Setup the signal handlers
+	 */
+	struct sigaction sa = {
+		.sa_sigaction = sig_t32,
+		.sa_flags = SA_SIGINFO,
+	};
+	ATF_REQUIRE(sigemptyset(&sa.sa_mask) == 0);
+	ATF_REQUIRE(sigaction(SIGUSR1, &sa, NULL) == 0);
+
+	ATF_CHECK(t32_fired == 0);
+	ATF_REQUIRE(raise(SIGUSR1) == 0);
+	ATF_CHECK(t32_fired == 1);
+}
+#endif
+
+ATF_TP_ADD_TCS(tp)
+{
+
+	ATF_TP_ADD_TC(tp, signal_test);
+#ifdef __arm__
+	ATF_TP_ADD_TC(tp, signal_test_T32_to_A32);
+	ATF_TP_ADD_TC(tp, signal_test_A32_to_T32);
+#endif
+
+	return (atf_no_error());
+}