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authorStefano Stabellini <stefano.stabellini@eu.citrix.com>2016-02-25 15:10:37 +0300
committerStefano Stabellini <stefano.stabellini@eu.citrix.com>2016-02-26 18:37:24 +0300
commit16e506efc08e5cab313588bd0e38803d4bbaad59 (patch)
tree7fc75d2f12469180b50205fb548641da24650124 /drivers/tty
parent81f70ba233d5f660e1ea5fe23260ee323af5d53a (diff)
downloadlinux-16e506efc08e5cab313588bd0e38803d4bbaad59.tar.xz
hvc_xen: add earlycon support
Introduce EARLYCON support in hvc_xen, useful for early debugging on arm and arm64, where xen early_printk is not available. It is different from xenboot_write_console on x86 in two ways: - it does not return if !xen_pv_domain(), not only because ARM guests are xen_hvm_domain(), but also because we want to capture all the early boot messages, before xen support is discovered - it does not try to print to the domU console at all, because xen support will only be discovered at a later point Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Diffstat (limited to 'drivers/tty')
-rw-r--r--drivers/tty/hvc/hvc_xen.c16
1 files changed, 16 insertions, 0 deletions
diff --git a/drivers/tty/hvc/hvc_xen.c b/drivers/tty/hvc/hvc_xen.c
index fa816b7193b6..68b8ec886bec 100644
--- a/drivers/tty/hvc/hvc_xen.c
+++ b/drivers/tty/hvc/hvc_xen.c
@@ -25,6 +25,7 @@
#include <linux/init.h>
#include <linux/types.h>
#include <linux/list.h>
+#include <linux/serial_core.h>
#include <asm/io.h>
#include <asm/xen/hypervisor.h>
@@ -664,3 +665,18 @@ void xen_raw_printk(const char *fmt, ...)
xen_raw_console_write(buf);
}
+
+static void xenboot_earlycon_write(struct console *console,
+ const char *string,
+ unsigned len)
+{
+ dom0_write_console(0, string, len);
+}
+
+static int __init xenboot_earlycon_setup(struct earlycon_device *device,
+ const char *opt)
+{
+ device->con->write = xenboot_earlycon_write;
+ return 0;
+}
+EARLYCON_DECLARE(xenboot, xenboot_earlycon_setup);