1 files changed, 59 insertions, 0 deletions
diff --git a/arch/um/kernel/kmsg_dump.c b/arch/um/kernel/kmsg_dump.c
new file mode 100644
index 000000000..0224fcb36
--- /dev/null
+++ b/arch/um/kernel/kmsg_dump.c
@@ -0,0 +1,59 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/kmsg_dump.h>
+#include <linux/spinlock.h>
+#include <linux/console.h>
+#include <linux/string.h>
+#include <shared/init.h>
+#include <shared/kern.h>
+#include <os.h>
+
+static void kmsg_dumper_stdout(struct kmsg_dumper *dumper,
+				enum kmsg_dump_reason reason)
+{
+	static struct kmsg_dump_iter iter;
+	static DEFINE_SPINLOCK(lock);
+	static char line[1024];
+	struct console *con;
+	unsigned long flags;
+	size_t len = 0;
+
+	/* only dump kmsg when no console is available */
+	if (!console_trylock())
+		return;
+
+	for_each_console(con) {
+		if(strcmp(con->name, "tty") == 0 &&
+		   (con->flags & (CON_ENABLED | CON_CONSDEV)) != 0) {
+			break;
+		}
+	}
+
+	console_unlock();
+
+	if (con)
+		return;
+
+	if (!spin_trylock_irqsave(&lock, flags))
+		return;
+
+	kmsg_dump_rewind(&iter);
+
+	printf("kmsg_dump:\n");
+	while (kmsg_dump_get_line(&iter, true, line, sizeof(line), &len)) {
+		line[len] = '\0';
+		printf("%s", line);
+	}
+
+	spin_unlock_irqrestore(&lock, flags);
+}
+
+static struct kmsg_dumper kmsg_dumper = {
+	.dump = kmsg_dumper_stdout
+};
+
+int __init kmsg_dumper_stdout_init(void)
+{
+	return kmsg_dump_register(&kmsg_dumper);
+}
+
+__uml_postsetup(kmsg_dumper_stdout_init);