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-rw-r--r--arch/s390/kernel/early_printk.c36
1 files changed, 36 insertions, 0 deletions
diff --git a/arch/s390/kernel/early_printk.c b/arch/s390/kernel/early_printk.c
new file mode 100644
index 000000000..d9d53f440
--- /dev/null
+++ b/arch/s390/kernel/early_printk.c
@@ -0,0 +1,36 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright IBM Corp. 2017
+ */
+
+#include <linux/console.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <asm/sclp.h>
+
+static void sclp_early_write(struct console *con, const char *s, unsigned int len)
+{
+ __sclp_early_printk(s, len);
+}
+
+static struct console sclp_early_console = {
+ .name = "earlysclp",
+ .write = sclp_early_write,
+ .flags = CON_PRINTBUFFER | CON_BOOT,
+ .index = -1,
+};
+
+static int __init setup_early_printk(char *buf)
+{
+ if (early_console)
+ return 0;
+ /* Accept only "earlyprintk" and "earlyprintk=sclp" */
+ if (buf && !str_has_prefix(buf, "sclp"))
+ return 0;
+ if (!sclp.has_linemode && !sclp.has_vt220)
+ return 0;
+ early_console = &sclp_early_console;
+ register_console(early_console);
+ return 0;
+}
+early_param("earlyprintk", setup_early_printk);