init/main: Add trace points for logging boot time on x86

Use debug I/O port `0x80` to log boot time for Cloud Hypervisor. Details: https://github.com/cloud-hypervisor/cloud-hypervisor/blob/main/docs/debug-port.md Signed-off-by: Bo Chen <[email protected]>
cloud-hypervisor · Mar 8, 2023 · 44b63c0 · 44b63c0
1 parent 8b33298
commit 44b63c0
Showing 1 changed file with 8 additions and 0 deletions.
diff --git a/init/main.c b/init/main.c
@@ -942,6 +942,10 @@ asmlinkage __visible void __init __no_sanitize_address start_kernel(void)
 	char *command_line;
 	char *after_dashes;
 
+#ifdef CONFIG_X86
+	outb(0x40, 0x80);
+#endif
+
 	set_task_stack_end_magic(&init_task);
 	smp_setup_processor_id();
 	debug_objects_early_init();
@@ -1544,6 +1548,10 @@ static int __ref kernel_init(void *unused)
 
 	do_sysctl_args();
 
+#ifdef CONFIG_X86
+	outb(0x41, 0x80);
+#endif
+
 	if (ramdisk_execute_command) {
 		ret = run_init_process(ramdisk_execute_command);
 		if (!ret)