zephyr: test: Test `crash` console command

Test various `crash` subcommands that cause different types of fatal
errors. Not all were possible to test due to limitations with running
these on a PC. Also had to make a tweak to the busy loops in the
watchdog and hang subcommands so that they don't interfere with the
simulated sys clock in native_posix. Add a public wrapper function for
calling the crash command outside of the shell interface so we don't
mess up its internal state when the command doesn't return.

BUG=None
BRANCH=None
TEST=./twister

Signed-off-by: Tristan Honscheid <honscheid@google.com>
Change-Id: I393e26441d44c0a5edaf1359413efe6280703add
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/4053360
Reviewed-by: Keith Short <keithshort@chromium.org>
Code-Coverage: Zoss <zoss-cl-coverage@prod.google.com>

7 files changed, 220 insertions, 4 deletions

diff --git a/common/panic_output.c b/common/panic_output.c
index fd163b21f5..066eb05d6f 100644
--- a/common/panic_output.c
+++ b/common/panic_output.c
@@ -373,13 +373,21 @@ static int command_crash(int argc, const char **argv)
 		cflush();
 		ccprintf("%08x", *(volatile int *)unaligned_ptr);
 	} else if (!strcasecmp(argv[1], "watchdog")) {
-		while (1)
-			;
+		while (1) {
+/* Yield on native posix to avoid locking up the simulated sys clock */
+#ifdef CONFIG_ARCH_POSIX
+			k_cpu_idle();
+#endif
+		}
 	} else if (!strcasecmp(argv[1], "hang")) {
 		uint32_t lock_key = irq_lock();
 
-		while (1)
-			;
+		while (1) {
+/* Yield on native posix to avoid locking up the simulated sys clock */
+#ifdef CONFIG_ARCH_POSIX
+			k_cpu_idle();
+#endif
+		}
 
 		/* Unreachable, but included for consistency */
 		irq_unlock(lock_key);
@@ -390,6 +398,7 @@ static int command_crash(int argc, const char **argv)
 	/* Everything crashes, so shouldn't get back here */
 	return EC_ERROR_UNKNOWN;
 }
+
 DECLARE_CONSOLE_COMMAND(crash, command_crash,
 			"[assert | divzero | udivzero"
 #ifdef CONFIG_CMD_STACKOVERFLOW
@@ -397,6 +406,13 @@ DECLARE_CONSOLE_COMMAND(crash, command_crash,
 #endif
 			" | unaligned | watchdog | hang]",
 			"Crash the system (for testing)");
+
+#ifdef TEST_BUILD
+int test_command_crash(int argc, const char **argv)
+{
+	return command_crash(argc, argv);
+}
+#endif /* TEST_BUILD*/
 #endif /* CONFIG_CMD_CRASH */
 
 static int command_panicinfo(int argc, const char **argv)
diff --git a/include/panic.h b/include/panic.h
index efd3e4d86b..44f21c7ab5 100644
--- a/include/panic.h
+++ b/include/panic.h
@@ -325,4 +325,20 @@ void chip_panic_data_backup(void);
 }
 #endif
 
+#ifdef TEST_BUILD
+/**
+ * @brief Wrapper for accessing the command_crash() console command
+ * implementation directly in unit tests. It cannot be called normally through
+ * the shell interface because it upsets the shell's internal state when the
+ * command doesn't return after a crash. command_crash() cannot be marked
+ * test_export_static directly due to an implementation detail in
+ * DECLARE_CONSOLE_COMMAND().
+ *
+ * @param argc Number of CLI args in `argv`
+ * @param argv CLI arguments
+ * @return int Return value
+ */
+int test_command_crash(int argc, const char **argv);
+#endif /* TEST_BUILD*/
+
 #endif /* __CROS_EC_PANIC_H */
diff --git a/zephyr/test/drivers/CMakeLists.txt b/zephyr/test/drivers/CMakeLists.txt
index 78c1274843..ffe3733762 100644
--- a/zephyr/test/drivers/CMakeLists.txt
+++ b/zephyr/test/drivers/CMakeLists.txt
@@ -25,6 +25,7 @@ add_subdirectory_ifdef(CONFIG_LINK_TEST_SUITE_I2C_CONTROLLER i2c_controller)
 add_subdirectory_ifdef(CONFIG_LINK_TEST_SUITE_KEYBOARD_SCAN keyboard_scan)
 add_subdirectory_ifdef(CONFIG_LINK_TEST_SUITE_LED_DRIVER led_driver)
 add_subdirectory_ifdef(CONFIG_LINK_TEST_SUITE_MKBP mkbp)
+add_subdirectory_ifdef(CONFIG_LINK_TEST_SUITE_PANIC_OUTPUT panic_output)
 add_subdirectory_ifdef(CONFIG_LINK_TEST_SUITE_POWER_HOST_SLEEP power_host_sleep)
 add_subdirectory_ifdef(CONFIG_LINK_TEST_SUITE_RT9490 rt9490)
 add_subdirectory_ifdef(CONFIG_LINK_TEST_SUITE_SHIM_GPIO_ID shim_gpio_id)
diff --git a/zephyr/test/drivers/Kconfig b/zephyr/test/drivers/Kconfig
index b2a9648f21..e5c66946c0 100644
--- a/zephyr/test/drivers/Kconfig
+++ b/zephyr/test/drivers/Kconfig
@@ -62,6 +62,9 @@ config LINK_TEST_SUITE_LOCATE_CHIP_ALTS
 config LINK_TEST_SUITE_MKBP
 	bool "Link and test the mkbp tests"
 
+config LINK_TEST_SUITE_PANIC_OUTPUT
+	bool "Link and test the panic_output tests"
+
 config LINK_TEST_SUITE_POWER_HOST_SLEEP
 	bool "Link and run the power/host_sleep.c specific tests"
 
diff --git a/zephyr/test/drivers/panic_output/CMakeLists.txt b/zephyr/test/drivers/panic_output/CMakeLists.txt
new file mode 100644
index 0000000000..79cf21fc5f
--- /dev/null
+++ b/zephyr/test/drivers/panic_output/CMakeLists.txt
@@ -0,0 +1,8 @@
+# Copyright 2022 The ChromiumOS Authors
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+# Add source files
+target_sources(app PRIVATE
+  src/panic_output_crash_cmd.c
+)
diff --git a/zephyr/test/drivers/panic_output/src/panic_output_crash_cmd.c b/zephyr/test/drivers/panic_output/src/panic_output_crash_cmd.c
new file mode 100644
index 0000000000..9608869609
--- /dev/null
+++ b/zephyr/test/drivers/panic_output/src/panic_output_crash_cmd.c
@@ -0,0 +1,167 @@
+/* Copyright 2022 The ChromiumOS Authors
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include <stdint.h>
+#include <signal.h>
+#include <stdio.h>
+#include <zephyr/shell/shell.h>
+#include <zephyr/ztest.h>
+#include <zephyr/kernel.h>
+#include <zephyr/ztest_assert.h>
+
+#include "console.h"
+#include "panic.h"
+#include "test/drivers/test_state.h"
+
+/* Special return codes for run_crash_command() */
+#define RETURN_CODE_CRASHED (-1)
+#define RETURN_CODE_TIMEOUT (-2)
+
+/** Create a new thread for running the `crash` console command. As its name
+ * suggests, this command causes a number of fatal errors (e.g. divide by zero).
+ * Run it in a separate thread so that we can observe these crashes without
+ * causing the ztest thread that runs the test functions to get aborted.
+ */
+static struct k_thread crash_thread;
+
+/* Create a stack for the crash thread */
+K_THREAD_STACK_DEFINE(crash_thread_stack, 1024);
+
+/** Captures the last signal number received by `handle_signal()`. */
+static int signal_received;
+
+/**
+ * @brief Handler for signals sent to the process. Log the signal number and
+ *        abort the crash test.
+ *
+ * @param sig Signal number, from signal.h
+ */
+void handle_signal(int sig)
+{
+	signal_received = sig;
+
+	k_thread_abort(&crash_thread);
+}
+
+/**
+ * @brief Worker function for the crash thread that calls the `crash` console
+ *        command.
+ *
+ * @param a The value of `argc` (forced as a pointer type).
+ * @param b `argv` pointer.
+ * @param c Pointer to location to write the return value.
+ */
+static void crash_thread_worker(void *a, void *b, void *c)
+{
+	int argc = (int)a;
+	const char **argv = (const char **)b;
+	int *return_val = c;
+
+	/* If the return value remains RETURN_CODE_CRASHED, then the command
+	 * did not return.
+	 */
+	*return_val = RETURN_CODE_CRASHED;
+	signal_received = 0;
+
+	*return_val = test_command_crash(argc, argv);
+}
+
+/**
+ * @brief Helper function to spawn a new thread that runs the `crash` console
+ *        command. Waits for the command to exit/fail.
+ *
+ * @param argc Number of elements in `argv`
+ * @param argv CLI arguments to pass to command. Include the command name.
+ * @param timeout Time to wait for the thread to exit, in milliseconds.
+ * @return int Console command's return value, or RETURN_CODE_CRASHED if caused
+ *         a fatal error, or RETURN_CODE_TIMEOUT if it hung.
+ */
+static int run_crash_command(int argc, const char **argv, k_timeout_t timeout)
+{
+	static int return_val;
+
+	k_thread_create(&crash_thread, crash_thread_stack,
+			K_THREAD_STACK_SIZEOF(crash_thread_stack),
+			(k_thread_entry_t)crash_thread_worker, (void *)argc,
+			argv, &return_val, CONFIG_ZTEST_THREAD_PRIORITY + 1,
+			K_INHERIT_PERMS, K_NO_WAIT);
+
+	if (k_thread_join(&crash_thread, timeout) == -EAGAIN) {
+		k_thread_abort(&crash_thread);
+		return RETURN_CODE_TIMEOUT;
+	}
+
+	return return_val;
+}
+
+ZTEST(panic_output, test_console_cmd__unaligned)
+{
+	int rv;
+	const char *cmd[] = { "crash", "unaligned" };
+
+	rv = run_crash_command(2, cmd, K_FOREVER);
+
+	zassert_equal(RETURN_CODE_CRASHED, rv,
+		      "Command returned %d but shouldn't have exited", rv);
+	zassert_equal(SIGSEGV, signal_received);
+}
+
+ZTEST(panic_output, test_console_cmd__watchdog)
+{
+	/* Note: this does not verify that the watchdog fired, but that is
+	 * covered in a different test suite.
+	 */
+
+	int rv;
+	const char *cmd[] = { "crash", "watchdog" };
+
+	rv = run_crash_command(2, cmd, K_MSEC(100));
+
+	zassert_equal(RETURN_CODE_TIMEOUT, rv,
+		      "Command returned %d but shouldn't have exited", rv);
+}
+
+ZTEST(panic_output, test_console_cmd__hang)
+{
+	int rv;
+	const char *cmd[] = { "crash", "hang" };
+
+	rv = run_crash_command(2, cmd, K_MSEC(100));
+
+	zassert_equal(RETURN_CODE_TIMEOUT, rv,
+		      "Command returned %d but shouldn't have exited", rv);
+}
+
+ZTEST(panic_output, test_console_cmd__bad_param)
+{
+	int rv;
+	const char *cmd[] = { "crash", "xyz" };
+
+	rv = run_crash_command(2, cmd, K_FOREVER);
+
+	zassert_equal(EC_ERROR_PARAM1, rv, "Command returned %d", rv);
+}
+
+ZTEST(panic_output, test_console_cmd__no_param)
+{
+	int rv;
+	const char *cmd[] = { "crash" };
+
+	rv = run_crash_command(1, cmd, K_FOREVER);
+
+	zassert_equal(EC_ERROR_PARAM1, rv, "Command returned %d", rv);
+}
+
+static void reset(void *data)
+{
+	ARG_UNUSED(data);
+
+	signal(SIGSEGV, handle_signal);
+	signal(SIGFPE, handle_signal);
+	signal_received = 0;
+}
+
+ZTEST_SUITE(panic_output, drivers_predicate_post_main, NULL, reset, reset,
+	    NULL);
diff --git a/zephyr/test/drivers/testcase.yaml b/zephyr/test/drivers/testcase.yaml
index 68e77fab94..39c2fe12f3 100644
--- a/zephyr/test/drivers/testcase.yaml
+++ b/zephyr/test/drivers/testcase.yaml
@@ -145,6 +145,11 @@ tests:
     tags:
       common
       mkbp
+  drivers.panic_output:
+    extra_configs:
+      - CONFIG_LINK_TEST_SUITE_PANIC_OUTPUT=y
+      - CONFIG_PLATFORM_EC_CONSOLE_CMD_CRASH=y
+      - CONFIG_ZTEST_THREAD_PRIORITY=1
   drivers.power_host_sleep:
     extra_configs:
       - CONFIG_LINK_TEST_SUITE_POWER_HOST_SLEEP=y