From 5ffc99a9a0293cb68c34894201d54d86b6561906 Mon Sep 17 00:00:00 2001
From: Stefano Garzarella <address@hidden>
Date: Fri, 30 Nov 2018 16:56:28 +0100
Subject: [PATCH] boot: add debug port write to trace boot times

---
 init/benchmark.h | 16 ++++++++++++++++
 init/main.c      |  5 +++++
 2 files changed, 21 insertions(+)
 create mode 100644 init/benchmark.h

diff --git a/init/benchmark.h b/init/benchmark.h
new file mode 100644
index 000000000000..372a26b05ab1
--- /dev/null
+++ b/init/benchmark.h
@@ -0,0 +1,16 @@
+#ifndef BENCHMARK_H
+#define BENCHMARK_H
+
+/* IO ports for different exit points */
+#define LINUX_EXIT_PORT 0xf4
+#define FW_EXIT_PORT    0xf5
+
+/* Exit point values */
+#define FW_START    1
+#define LINUX_START_FWCFG 2
+#define LINUX_START_BOOT  3
+#define FW_DO_BOOT 4
+#define LINUX_START_KERNEL 5
+#define LINUX_START_USER 6
+
+#endif
diff --git a/init/main.c b/init/main.c
index c4a45145e102..05f9cc85d07d 100644
--- a/init/main.c
+++ b/init/main.c
@@ -10,6 +10,7 @@
  */
 
 #define DEBUG		/* Enable initcall_debug */
+#include "benchmark.h"
 
 #include <linux/types.h>
 #include <linux/extable.h>
@@ -515,6 +516,8 @@ asmlinkage __visible void __init start_kernel(void)
 	char *command_line;
 	char *after_dashes;
 
+	outb(LINUX_START_KERNEL, LINUX_EXIT_PORT);
+
 	set_task_stack_end_magic(&init_task);
 	smp_setup_processor_id();
 	debug_objects_early_init();
@@ -1008,6 +1011,8 @@ static int __ref kernel_init(void *unused)
 
 	rcu_end_inkernel_boot();
 
+	outb(LINUX_START_USER, LINUX_EXIT_PORT);
+
 	if (ramdisk_execute_command) {
 		ret = run_init_process(ramdisk_execute_command);
 		if (!ret)
-- 
2.19.2