test: userspace: add a sys_sem test

Add a sys_sem test between kernel- and user-space.

Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>

Author: lyakh

zephyr/test/userspace/ksem.c

@@ -57,6 +57,67 @@ ZTEST(sof_boot, user_space)
 {
 	test_user_thread();
 	test_user_thread_with_sem();
+}
+
+#include <zephyr/sys/sem.h>
+#include <zephyr/app_memory/mem_domain.h>
+
+struct sem_mem {
+	struct sys_sem sem;
+	uint8_t reserved[4096 - sizeof(struct sys_sem)];
+};
+
+static struct sem_mem simple_sem __attribute__((aligned(4096)));
+static struct k_mem_domain dp_mdom;
+
+static void sys_sem_function(void *p1, void *p2, void *p3)
+{
+	__ASSERT(k_is_user_context(), "isn't user");
+	LOG_INF("SOF thread %s (%s)",
+	       k_is_user_context() ? "UserSpace!" : "privileged mode.",
+	       CONFIG_BOARD_TARGET);
+#if 0
+	/* This is the goal, but it hangs with this disabled too */
+	sys_sem_give(&simple_sem.sem);
+#endif
+}
 
-	ztest_test_pass();
+static void test_user_thread_sys_sem(void)
+{
+	struct k_mem_partition mpart = {
+		.start = (uintptr_t)&simple_sem,
+		.size = 4096,
+		.attr = K_MEM_PARTITION_P_RW_U_RW/* | XTENSA_MMU_CACHED_WB*/,
+	};
+
+	k_mem_domain_init(&dp_mdom, 0, NULL);
+	sys_sem_init(&simple_sem.sem, 0, 1);
+
+	k_thread_create(&user_thread, user_stack, USER_STACKSIZE,
+			sys_sem_function, NULL, NULL, NULL,
+			-1, K_USER, K_FOREVER);
+	k_mem_domain_add_partition(&dp_mdom, &mpart);
+	k_mem_domain_add_thread(&dp_mdom, &user_thread);
+
+#if 0
+	/*
+	 * Do we need to also grant access to the futex in sys_sem? But this
+	 * isn't what's breaking execution, it breaks without user-space
+	 * accessing the semaphore at all.
+	 */
+	k_thread_access_grant(&user_thread, &simple_sem.sem.futex);
+#endif
+
+	k_thread_start(&user_thread);
+#if 0
+	/* This is what doesn't work: enabling this line crashes the DSP  */
+	sys_sem_take(&simple_sem.sem, K_MSEC(20));
+#endif
+	k_thread_join(&user_thread, K_FOREVER);
+	k_mem_domain_remove_partition(&dp_mdom, &mpart);
+}
+
+ZTEST(sof_boot, test_sys_sem)
+{
+	test_user_thread_sys_sem();
 }