Resguardo inicial

linux-7.2.3/arch/s390/kernel/early_printk.c

@@ -0,0 +1,44 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *    Copyright IBM Corp. 2017
+ */
+
+#include <linux/console.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <asm/setup.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,
+};
+
+void __init register_early_console(void)
+{
+	if (early_console)
+		return;
+	if (!sclp.has_linemode && !sclp.has_vt220)
+		return;
+	early_console = &sclp_early_console;
+	register_console(early_console);
+}
+
+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;
+	register_early_console();
+	return 0;
+}
+early_param("earlyprintk", setup_early_printk);