From 16e506efc08e5cab313588bd0e38803d4bbaad59 Mon Sep 17 00:00:00 2001 From: Stefano Stabellini Date: Thu, 25 Feb 2016 12:10:37 +0000 Subject: 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 Reviewed-by: Boris Ostrovsky --- drivers/tty/hvc/hvc_xen.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'drivers/tty/hvc') 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 #include #include +#include #include #include @@ -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); -- cgit v1.2.3