[patch 20/29] xen: Add early printk support via hvc console
From: Jeremy Fitzhardinge <hidden>
Date: 2007-05-04 23:43:06
Also in:
lkml
Add early printk support via hvc console, enable using "earlyprintk=xen" on the kernel command line. From: Gerd Hoffmann <redacted> Signed-off-by: Jeremy Fitzhardinge <redacted> Signed-off-by: Chris Wright <redacted> Acked-by: Ingo Molnar <redacted> --- arch/x86_64/kernel/early_printk.c | 5 +++++ drivers/char/hvc_xen.c | 25 +++++++++++++++++++++++++ drivers/xen/Makefile | 1 + include/xen/hvc-console.h | 6 ++++++ 4 files changed, 37 insertions(+) ===================================================================
--- a/arch/x86_64/kernel/early_printk.c
+++ b/arch/x86_64/kernel/early_printk.c@@ -6,6 +6,7 @@ #include <asm/io.h> #include <asm/processor.h> #include <asm/fcntl.h> +#include <xen/hvc-console.h> /* Simple VGA output */
@@ -242,6 +243,10 @@ static int __init setup_early_printk(cha simnow_init(buf + 6); early_console = &simnow_console; keep_early = 1; +#ifdef CONFIG_XEN + } else if (!strncmp(buf, "xen", 3)) { + early_console = &xenboot_console; +#endif } register_console(early_console); return 0;
===================================================================
--- a/drivers/char/hvc_xen.c
+++ b/drivers/char/hvc_xen.c@@ -28,6 +28,7 @@ #include <xen/page.h> #include <xen/events.h> #include <xen/interface/io/console.h> +#include <xen/hvc-console.h> #include "hvc_console.h"
@@ -132,3 +133,27 @@ module_init(xen_init); module_init(xen_init); module_exit(xen_fini); console_initcall(xen_cons_init); + +static void xenboot_write_console(struct console *console, const char *string, + unsigned len) +{ + unsigned int linelen, off = 0; + const char *pos; + + while (off < len && NULL != (pos = strchr(string+off, '\n'))) { + linelen = pos-string+off; + if (off + linelen > len) + break; + write_console(0, string+off, linelen); + write_console(0, "\r\n", 2); + off += linelen + 1; + } + if (off < len) + write_console(0, string+off, len-off); +} + +struct console xenboot_console = { + .name = "xenboot", + .write = xenboot_write_console, + .flags = CON_PRINTBUFFER | CON_BOOT, +};
===================================================================
--- /dev/null
+++ b/drivers/xen/Makefile@@ -0,0 +1,1 @@ +obj-y += grant-table.o
===================================================================
--- /dev/null
+++ b/include/xen/hvc-console.h@@ -0,0 +1,6 @@ +#ifndef XEN_HVC_CONSOLE_H +#define XEN_HVC_CONSOLE_H + +extern struct console xenboot_console; + +#endif /* XEN_HVC_CONSOLE_H */
--