emulator: Move trace dump to a separate module

The implementation of trace dump has little to do with task scheduling,
so we should move it to a separate module for cleaner code. This
requires exposing some emulator-specific task info, as defined in
host_task.h.

BUG=chrome-os-partner:19235
TEST=Pass all tests
BRANCH=None

Change-Id: Iba9bc0794a4e1dd4ddb92b98345162b398fa6a8d
Signed-off-by: Vic (Chun-Ju) Yang <victoryang@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/183238

10 files changed, 174 insertions, 97 deletions

diff --git a/core/host/build.mk b/core/host/build.mk
index 121ef98272..183714f6c4 100644
--- a/core/host/build.mk
+++ b/core/host/build.mk
@@ -8,4 +8,4 @@
 
 CFLAGS_CPU=-fno-builtin
 
-core-y=main.o task.o timer.o panic.o disabled.o
+core-y=main.o task.o timer.o panic.o disabled.o stack_trace.o
diff --git a/core/host/host_task.h b/core/host/host_task.h
new file mode 100644
index 0000000000..e4e0712ea2
--- /dev/null
+++ b/core/host/host_task.h
@@ -0,0 +1,26 @@
+/* Copyright (c) 2014 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+/* Emulator task scheduling module */
+
+#ifndef __CROS_EC_HOST_TASK_H
+#define __CROS_EC_HOST_TASK_H
+
+#include <pthread.h>
+
+#include "task.h"
+
+/**
+ * Returns the thread corresponding to the task.
+ */
+pthread_t task_get_thread(task_id_t tskid);
+
+/**
+ * Returns the ID of the active task, regardless of current thread
+ * context.
+ */
+task_id_t task_get_running(void);
+
+#endif  /* __CROS_EC_HOST_TASK_H */
diff --git a/core/host/main.c b/core/host/main.c
index 2d3622c269..fa5077b33d 100644
--- a/core/host/main.c
+++ b/core/host/main.c
@@ -9,6 +9,7 @@
 #include "flash.h"
 #include "hooks.h"
 #include "keyboard_scan.h"
+#include "stack_trace.h"
 #include "system.h"
 #include "task.h"
 #include "test_util.h"
diff --git a/core/host/panic.c b/core/host/panic.c
index 260329cc39..ee21577aec 100644
--- a/core/host/panic.c
+++ b/core/host/panic.c
@@ -8,6 +8,7 @@
 
 #include "common.h"
 #include "panic.h"
+#include "stack_trace.h"
 #include "test_util.h"
 #include "util.h"
 
diff --git a/core/host/stack_trace.c b/core/host/stack_trace.c
new file mode 100644
index 0000000000..67ceac5891
--- /dev/null
+++ b/core/host/stack_trace.c
@@ -0,0 +1,97 @@
+/* Copyright (c) 2014 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include <execinfo.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "host_task.h"
+#include "host_test.h"
+#include "timer.h"
+
+#define SIGNAL_TRACE_DUMP SIGTERM
+#define MAX_TRACE 30
+/*
+ * When trace dump is requested from signal handler, skip:
+ *   _task_dump_trace_impl
+ *   _task_dump_trace_dispath
+ *   A function in libc
+ */
+#define SIGNAL_TRACE_OFFSET 3
+/*
+ * When trace dump is requested from task_dump_trace(), skip:
+ *   task_dump_trace
+ *   _task_dump_trace_impl
+ */
+#define DIRECT_TRACE_OFFSET 2
+
+static pthread_t main_thread;
+
+static void __attribute__((noinline)) _task_dump_trace_impl(int offset)
+{
+	void *trace[MAX_TRACE];
+	size_t sz;
+	char **messages;
+	char buf[256];
+	FILE *file;
+	int i, nb;
+
+	sz = backtrace(trace, MAX_TRACE);
+	messages = backtrace_symbols(trace + offset, sz - offset);
+
+	for (i = 0; i < sz - offset; ++i) {
+		fprintf(stderr, "#%-2d %s\n", i, messages[i]);
+		sprintf(buf, "addr2line %p -e %s",
+			trace[i + offset], __get_prog_name());
+		file = popen(buf, "r");
+		if (file) {
+			nb = fread(buf, 1, sizeof(buf) - 1, file);
+			buf[nb] = '\0';
+			fprintf(stderr, "    %s", buf);
+			pclose(file);
+		}
+	}
+	fflush(stderr);
+	free(messages);
+}
+
+void __attribute__((noinline)) task_dump_trace(void)
+{
+	_task_dump_trace_impl(DIRECT_TRACE_OFFSET);
+}
+
+static void __attribute__((noinline)) _task_dump_trace_dispatch(int sig)
+{
+	int need_dispatch = 1;
+	task_id_t running = task_get_running();
+
+	if (!pthread_equal(pthread_self(), main_thread)) {
+		need_dispatch = 0;
+	} else if (!task_start_called()) {
+		fprintf(stderr, "Stack trace of main thread:\n");
+		need_dispatch = 0;
+	} else if (in_interrupt_context()) {
+		fprintf(stderr, "Stack trace of ISR:\n");
+	} else {
+		fprintf(stderr, "Stack trace of task %d (%s):\n",
+				running, task_get_name(running));
+	}
+
+	if (need_dispatch) {
+		pthread_kill(task_get_thread(running), SIGNAL_TRACE_DUMP);
+	} else {
+		_task_dump_trace_impl(SIGNAL_TRACE_OFFSET);
+		udelay(100 * MSEC); /* Leave time for stderr to flush */
+		exit(1);
+	}
+}
+
+void task_register_tracedump(void)
+{
+	/* Trace dumper MUST be registered from main thread */
+	main_thread = pthread_self();
+	signal(SIGNAL_TRACE_DUMP, _task_dump_trace_dispatch);
+}
diff --git a/core/host/task.c b/core/host/task.c
index 08c70da66b..5bff856def 100644
--- a/core/host/task.c
+++ b/core/host/task.c
@@ -5,7 +5,6 @@
 
 /* Task scheduling / events module for Chrome EC operating system */
 
-#include <execinfo.h>
 #include <malloc.h>
 #include <pthread.h>
 #include <semaphore.h>
@@ -18,7 +17,7 @@
 #include "atomic.h"
 #include "common.h"
 #include "console.h"
-#include "host_test.h"
+#include "host_task.h"
 #include "task.h"
 #include "task_id.h"
 #include "test_util.h"
@@ -26,22 +25,6 @@
 
 #define SIGNAL_INTERRUPT SIGUSR1
 
-#define SIGNAL_TRACE_DUMP SIGTERM
-#define MAX_TRACE 30
-/*
- * When trace dump is requested from signal handler, skip:
- *   _task_dump_trace_impl
- *   _task_dump_trace_dispath
- *   A function in libc
- */
-#define SIGNAL_TRACE_OFFSET 3
-/*
- * When trace dump is requested from task_dump_trace(), skip:
- *   task_dump_trace
- *   _task_dump_trace_impl
- */
-#define DIRECT_TRACE_OFFSET 2
-
 struct emu_task_t {
 	pthread_t thread;
 	pthread_cond_t resume;
@@ -60,7 +43,6 @@ static pthread_cond_t scheduler_cond;
 static pthread_mutex_t run_lock;
 static task_id_t running_task_id;
 static int task_started;
-static pthread_t main_thread;
 
 static sem_t interrupt_sem;
 static pthread_mutex_t interrupt_lock;
@@ -141,71 +123,6 @@ static void _task_execute_isr(int sig)
 	in_interrupt = 0;
 }
 
-static void __attribute__((noinline)) _task_dump_trace_impl(int offset)
-{
-	void *trace[MAX_TRACE];
-	size_t sz;
-	char **messages;
-	char buf[256];
-	FILE *file;
-	int i, nb;
-
-	sz = backtrace(trace, MAX_TRACE);
-	messages = backtrace_symbols(trace + offset, sz - offset);
-
-	for (i = 0; i < sz - offset; ++i) {
-		fprintf(stderr, "#%-2d %s\n", i, messages[i]);
-		sprintf(buf, "addr2line %p -e %s",
-			trace[i + offset], __get_prog_name());
-		file = popen(buf, "r");
-		if (file) {
-			nb = fread(buf, 1, sizeof(buf) - 1, file);
-			buf[nb] = '\0';
-			fprintf(stderr, "    %s", buf);
-			pclose(file);
-		}
-	}
-	fflush(stderr);
-	free(messages);
-}
-
-void __attribute__((noinline)) task_dump_trace(void)
-{
-	_task_dump_trace_impl(DIRECT_TRACE_OFFSET);
-}
-
-static void __attribute__((noinline)) _task_dump_trace_dispatch(int sig)
-{
-	int need_dispatch = 1;
-
-	if (!pthread_equal(pthread_self(), main_thread)) {
-		need_dispatch = 0;
-	} else if (!task_start_called()) {
-		fprintf(stderr, "Stack trace of main thread:\n");
-		need_dispatch = 0;
-	} else if (in_interrupt_context()) {
-		fprintf(stderr, "Stack trace of ISR:\n");
-	} else {
-		fprintf(stderr, "Stack trace of task %d (%s):\n",
-				running_task_id, task_names[running_task_id]);
-	}
-
-	if (need_dispatch) {
-		pthread_kill(tasks[running_task_id].thread, SIGNAL_TRACE_DUMP);
-	} else {
-		_task_dump_trace_impl(SIGNAL_TRACE_OFFSET);
-		udelay(100 * MSEC); /* Leave time for stderr to flush */
-		exit(1);
-	}
-}
-
-void task_register_tracedump(void)
-{
-	/* Trace dumper MUST be registered from main thread */
-	main_thread = pthread_self();
-	signal(SIGNAL_TRACE_DUMP, _task_dump_trace_dispatch);
-}
-
 static void task_register_interrupt(void)
 {
 	sem_init(&interrupt_sem, 0, 0);
@@ -242,6 +159,16 @@ void interrupt_generator_udelay(unsigned us)
 	generator_sleeping = 0;
 }
 
+const char *task_get_name(task_id_t tskid)
+{
+	return task_names[tskid];
+}
+
+pthread_t task_get_thread(task_id_t tskid)
+{
+	return tasks[tskid].thread;
+}
+
 uint32_t task_set_event(task_id_t tskid, uint32_t event, int wait)
 {
 	tasks[tskid].event = event;
@@ -307,6 +234,11 @@ task_id_t task_get_current(void)
 	return my_task_id;
 }
 
+task_id_t task_get_running(void)
+{
+	return running_task_id;
+}
+
 void wait_for_task_started(void)
 {
 	int i, ok;
diff --git a/include/stack_trace.h b/include/stack_trace.h
new file mode 100644
index 0000000000..e8b37d1811
--- /dev/null
+++ b/include/stack_trace.h
@@ -0,0 +1,25 @@
+/* Copyright (c) 2014 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+/* Trace dump module */
+
+#ifndef __CROS_EC_TRACE_H
+#define __CROS_EC_TRACE_H
+
+#ifdef EMU_BUILD
+/*
+ * Register trace dump handler for emulator. Trace dump is printed to stderr
+ * when SIGUSR2 is received.
+ */
+void task_register_tracedump(void);
+
+/* Dump current stack trace */
+void task_dump_trace(void);
+#else
+static inline void task_register_tracedump(void) { }
+static inline void task_dump_trace(void) { }
+#endif
+
+#endif  /* __CROS_EC_TRACE_H */
diff --git a/include/task.h b/include/task.h
index 1aeb1206b7..f2df173501 100644
--- a/include/task.h
+++ b/include/task.h
@@ -105,6 +105,11 @@ uint32_t task_wait_event(int timeout_us);
  */
 void task_print_list(void);
 
+/**
+ * Returns the name of the task.
+ */
+const char *task_get_name(task_id_t tskid);
+
 #ifdef CONFIG_TASK_PROFILING
 /**
  * Start tracking an interrupt.
diff --git a/include/test_util.h b/include/test_util.h
index 754230489f..4f76a200c4 100644
--- a/include/test_util.h
+++ b/include/test_util.h
@@ -10,6 +10,7 @@
 
 #include "common.h"
 #include "console.h"
+#include "stack_trace.h"
 
 #define RUN_TEST(n) \
 	do { \
@@ -130,19 +131,8 @@ void interrupt_generator_udelay(unsigned us);
 
 #ifdef EMU_BUILD
 void wait_for_task_started(void);
-
-/*
- * Register trace dump handler for emulator. Trace dump is printed to stderr
- * when SIGUSR2 is received.
- */
-void task_register_tracedump(void);
-
-/* Dump current stack trace */
-void task_dump_trace(void);
 #else
 static inline void wait_for_task_started(void) { }
-static inline void task_register_tracedump(void) { }
-static inline void task_dump_trace(void) { }
 #endif
 
 uint32_t prng(uint32_t seed);
diff --git a/test/interrupt.c b/test/interrupt.c
index b7a42d1588..ae8ce66b58 100644
--- a/test/interrupt.c
+++ b/test/interrupt.c
@@ -8,8 +8,8 @@
 
 #include "common.h"
 #include "console.h"
-#include "test_util.h"
 #include "task.h"
+#include "test_util.h"
 #include "timer.h"
 #include "util.h"