xen: use the hvc console infrastructure for Xen console

Implement a Xen back-end for hvc console. * * * Add early printk support via hvc console, enable using "earlyprintk=xen" on the kernel command line. From: Gerd Hoffmann <kraxel@suse.de> Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: Chris Wright <chrisw@sous-sol.org> Acked-by: Ingo Molnar <mingo@elte.hu> Acked-by: Olof Johansson <olof@lixom.net>

xen: use the hvc console infrastructure for Xen console
Implement a Xen back-end for hvc console. * * * Add early printk support via hvc console, enable using "earlyprintk=xen" on the kernel command line. From: Gerd Hoffmann <kraxel@suse.de> Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: Chris Wright <chrisw@sous-sol.org> Acked-by: Ingo Molnar <mingo@elte.hu> Acked-by: Olof Johansson <olof@lixom.net>
Jeremy Fitzhardinge · Jeremy Fitzhardinge
1 parent 8b84ad942b
Showing 7 changed files with 182 additions and 1 deletions Side-by-side Diff
arch/i386/xen/events.c
arch/x86_64/kernel/early_printk.c
drivers/char/Kconfig
drivers/char/Makefile
drivers/char/hvc_xen.c
include/xen/events.h
include/xen/hvc-console.h
@@ -244,7 +244,7 @@
 	return irq;
 }
  
-static int bind_evtchn_to_irq(unsigned int evtchn)
+int bind_evtchn_to_irq(unsigned int evtchn)
 {
 	int irq;
  
@@ -269,6 +269,7 @@
  
 	return irq;
 }
+EXPORT_SYMBOL_GPL(bind_evtchn_to_irq);
  
 static int bind_ipi_to_irq(unsigned int ipi, unsigned int cpu)
 {
@@ -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 @@
  		simnow_init(buf + 6);
  		early_console = &simnow_console;
  		keep_early = 1;
+#ifdef CONFIG_HVC_XEN
+	} else if (!strncmp(buf, "xen", 3)) {
+		early_console = &xenboot_console;
+#endif
 	}
  
 	if (keep_early)
@@ -604,6 +604,14 @@
 	help
 	  Toshiba's Cell Reference Set Beat Console device driver
  
+config HVC_XEN
+	bool "Xen Hypervisor Console support"
+	depends on XEN
+	select HVC_DRIVER
+	default y
+	help
+	  Xen virtual console device driver
+
 config HVCS
 	tristate "IBM Hypervisor Virtual Console Server support"
 	depends on PPC_PSERIES
@@ -48,6 +48,7 @@
 obj-$(CONFIG_HVC_RTAS)		+= hvc_rtas.o
 obj-$(CONFIG_HVC_BEAT)		+= hvc_beat.o
 obj-$(CONFIG_HVC_DRIVER)	+= hvc_console.o
+obj-$(CONFIG_HVC_XEN)		+= hvc_xen.o
 obj-$(CONFIG_RAW_DRIVER)	+= raw.o
 obj-$(CONFIG_SGI_SNSC)		+= snsc.o snsc_event.o
 obj-$(CONFIG_MSPEC)		+= mspec.o
+/*
+ * xen console driver interface to hvc_console.c
+ *
+ * (c) 2007 Gerd Hoffmann <kraxel@suse.de>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
+ */
+
+#include <linux/console.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/types.h>
+
+#include <asm/xen/hypervisor.h>
+#include <xen/page.h>
+#include <xen/events.h>
+#include <xen/interface/io/console.h>
+#include <xen/hvc-console.h>
+
+#include "hvc_console.h"
+
+#define HVC_COOKIE   0x58656e /* "Xen" in hex */
+
+static struct hvc_struct *hvc;
+static int xencons_irq;
+
+/* ------------------------------------------------------------------ */
+
+static inline struct xencons_interface *xencons_interface(void)
+{
+	return mfn_to_virt(xen_start_info->console.domU.mfn);
+}
+
+static inline void notify_daemon(void)
+{
+	/* Use evtchn: this is called early, before irq is set up. */
+	notify_remote_via_evtchn(xen_start_info->console.domU.evtchn);
+}
+
+static int write_console(uint32_t vtermno, const char *data, int len)
+{
+	struct xencons_interface *intf = xencons_interface();
+	XENCONS_RING_IDX cons, prod;
+	int sent = 0;
+
+	cons = intf->out_cons;
+	prod = intf->out_prod;
+	mb();			/* update queue values before going on */
+	BUG_ON((prod - cons) > sizeof(intf->out));
+
+	while ((sent < len) && ((prod - cons) < sizeof(intf->out)))
+		intf->out[MASK_XENCONS_IDX(prod++, intf->out)] = data[sent++];
+
+	wmb();			/* write ring before updating pointer */
+	intf->out_prod = prod;
+
+	notify_daemon();
+	return sent;
+}
+
+static int read_console(uint32_t vtermno, char *buf, int len)
+{
+	struct xencons_interface *intf = xencons_interface();
+	XENCONS_RING_IDX cons, prod;
+	int recv = 0;
+
+	cons = intf->in_cons;
+	prod = intf->in_prod;
+	mb();			/* get pointers before reading ring */
+	BUG_ON((prod - cons) > sizeof(intf->in));
+
+	while (cons != prod && recv < len)
+		buf[recv++] = intf->in[MASK_XENCONS_IDX(cons++, intf->in)];
+
+	mb();			/* read ring before consuming */
+	intf->in_cons = cons;
+
+	notify_daemon();
+	return recv;
+}
+
+static struct hv_ops hvc_ops = {
+	.get_chars = read_console,
+	.put_chars = write_console,
+};
+
+static int __init xen_init(void)
+{
+	struct hvc_struct *hp;
+
+	if (!is_running_on_xen())
+		return 0;
+
+	xencons_irq = bind_evtchn_to_irq(xen_start_info->console.domU.evtchn);
+	if (xencons_irq < 0)
+		xencons_irq = 0 /* NO_IRQ */;
+	hp = hvc_alloc(HVC_COOKIE, xencons_irq, &hvc_ops, 256);
+	if (IS_ERR(hp))
+		return PTR_ERR(hp);
+
+	hvc = hp;
+	return 0;
+}
+
+static void __exit xen_fini(void)
+{
+	if (hvc)
+		hvc_remove(hvc);
+}
+
+static int xen_cons_init(void)
+{
+	if (!is_running_on_xen())
+		return 0;
+
+	hvc_instantiate(HVC_COOKIE, 0, &hvc_ops);
+	return 0;
+}
+
+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,
+};
@@ -13,6 +13,7 @@
 	XEN_NR_IPIS,
 };
  
+int bind_evtchn_to_irq(unsigned int evtchn);
 int bind_evtchn_to_irqhandler(unsigned int evtchn,
 			      irq_handler_t handler,
 			      unsigned long irqflags, const char *devname,
+#ifndef XEN_HVC_CONSOLE_H
+#define XEN_HVC_CONSOLE_H
+
+extern struct console xenboot_console;
+
+#endif	/* XEN_HVC_CONSOLE_H */
...	...	@@ -244,7 +244,7 @@
244	244	return irq;
245	245	}
246	246
247		-static int bind_evtchn_to_irq(unsigned int evtchn)
	247	+int bind_evtchn_to_irq(unsigned int evtchn)
248	248	{
249	249	int irq;
250	250
...	...	@@ -269,6 +269,7 @@
269	269
270	270	return irq;
271	271	}
	272	+EXPORT_SYMBOL_GPL(bind_evtchn_to_irq);
272	273
273	274	static int bind_ipi_to_irq(unsigned int ipi, unsigned int cpu)
274	275	{
...	...	@@ -6,6 +6,7 @@
6	6	#include <asm/io.h>
7	7	#include <asm/processor.h>
8	8	#include <asm/fcntl.h>
	9	+#include <xen/hvc-console.h>
9	10
10	11	/* Simple VGA output */
11	12
...	...	@@ -242,6 +243,10 @@
242	243	simnow_init(buf + 6);
243	244	early_console = &simnow_console;
244	245	keep_early = 1;
	246	+#ifdef CONFIG_HVC_XEN
	247	+ } else if (!strncmp(buf, "xen", 3)) {
	248	+ early_console = &xenboot_console;
	249	+#endif
245	250	}
246	251
247	252	if (keep_early)
...	...	@@ -604,6 +604,14 @@
604	604	help
605	605	Toshiba's Cell Reference Set Beat Console device driver
606	606
	607	+config HVC_XEN
	608	+ bool "Xen Hypervisor Console support"
	609	+ depends on XEN
	610	+ select HVC_DRIVER
	611	+ default y
	612	+ help
	613	+ Xen virtual console device driver
	614	+
607	615	config HVCS
608	616	tristate "IBM Hypervisor Virtual Console Server support"
609	617	depends on PPC_PSERIES
...	...	@@ -48,6 +48,7 @@
48	48	obj-$(CONFIG_HVC_RTAS) += hvc_rtas.o
49	49	obj-$(CONFIG_HVC_BEAT) += hvc_beat.o
50	50	obj-$(CONFIG_HVC_DRIVER) += hvc_console.o
	51	+obj-$(CONFIG_HVC_XEN) += hvc_xen.o
51	52	obj-$(CONFIG_RAW_DRIVER) += raw.o
52	53	obj-$(CONFIG_SGI_SNSC) += snsc.o snsc_event.o
53	54	obj-$(CONFIG_MSPEC) += mspec.o
	1	+/*
	2	+ * xen console driver interface to hvc_console.c
	3	+ *
	4	+ * (c) 2007 Gerd Hoffmann <kraxel@suse.de>
	5	+ *
	6	+ * This program is free software; you can redistribute it and/or modify
	7	+ * it under the terms of the GNU General Public License as published by
	8	+ * the Free Software Foundation; either version 2 of the License, or
	9	+ * (at your option) any later version.
	10	+ *
	11	+ * This program is distributed in the hope that it will be useful,
	12	+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	14	+ * GNU General Public License for more details.
	15	+ *
	16	+ * You should have received a copy of the GNU General Public License
	17	+ * along with this program; if not, write to the Free Software
	18	+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	19	+ */
	20	+
	21	+#include <linux/console.h>
	22	+#include <linux/delay.h>
	23	+#include <linux/err.h>
	24	+#include <linux/init.h>
	25	+#include <linux/types.h>
	26	+
	27	+#include <asm/xen/hypervisor.h>
	28	+#include <xen/page.h>
	29	+#include <xen/events.h>
	30	+#include <xen/interface/io/console.h>
	31	+#include <xen/hvc-console.h>
	32	+
	33	+#include "hvc_console.h"
	34	+
	35	+#define HVC_COOKIE 0x58656e /* "Xen" in hex */
	36	+
	37	+static struct hvc_struct *hvc;
	38	+static int xencons_irq;
	39	+
	40	+/* ------------------------------------------------------------------ */
	41	+
	42	+static inline struct xencons_interface *xencons_interface(void)
	43	+{
	44	+ return mfn_to_virt(xen_start_info->console.domU.mfn);
	45	+}
	46	+
	47	+static inline void notify_daemon(void)
	48	+{
	49	+ /* Use evtchn: this is called early, before irq is set up. */
	50	+ notify_remote_via_evtchn(xen_start_info->console.domU.evtchn);
	51	+}
	52	+
	53	+static int write_console(uint32_t vtermno, const char *data, int len)
	54	+{
	55	+ struct xencons_interface *intf = xencons_interface();
	56	+ XENCONS_RING_IDX cons, prod;
	57	+ int sent = 0;
	58	+
	59	+ cons = intf->out_cons;
	60	+ prod = intf->out_prod;
	61	+ mb(); /* update queue values before going on */
	62	+ BUG_ON((prod - cons) > sizeof(intf->out));
	63	+
	64	+ while ((sent < len) && ((prod - cons) < sizeof(intf->out)))
	65	+ intf->out[MASK_XENCONS_IDX(prod++, intf->out)] = data[sent++];
	66	+
	67	+ wmb(); /* write ring before updating pointer */
	68	+ intf->out_prod = prod;
	69	+
	70	+ notify_daemon();
	71	+ return sent;
	72	+}
	73	+
	74	+static int read_console(uint32_t vtermno, char *buf, int len)
	75	+{
	76	+ struct xencons_interface *intf = xencons_interface();
	77	+ XENCONS_RING_IDX cons, prod;
	78	+ int recv = 0;
	79	+
	80	+ cons = intf->in_cons;
	81	+ prod = intf->in_prod;
	82	+ mb(); /* get pointers before reading ring */
	83	+ BUG_ON((prod - cons) > sizeof(intf->in));
	84	+
	85	+ while (cons != prod && recv < len)
	86	+ buf[recv++] = intf->in[MASK_XENCONS_IDX(cons++, intf->in)];
	87	+
	88	+ mb(); /* read ring before consuming */
	89	+ intf->in_cons = cons;
	90	+
	91	+ notify_daemon();
	92	+ return recv;
	93	+}
	94	+
	95	+static struct hv_ops hvc_ops = {
	96	+ .get_chars = read_console,
	97	+ .put_chars = write_console,
	98	+};
	99	+
	100	+static int __init xen_init(void)
	101	+{
	102	+ struct hvc_struct *hp;
	103	+
	104	+ if (!is_running_on_xen())
	105	+ return 0;
	106	+
	107	+ xencons_irq = bind_evtchn_to_irq(xen_start_info->console.domU.evtchn);
	108	+ if (xencons_irq < 0)
	109	+ xencons_irq = 0 /* NO_IRQ */;
	110	+ hp = hvc_alloc(HVC_COOKIE, xencons_irq, &hvc_ops, 256);
	111	+ if (IS_ERR(hp))
	112	+ return PTR_ERR(hp);
	113	+
	114	+ hvc = hp;
	115	+ return 0;
	116	+}
	117	+
	118	+static void __exit xen_fini(void)
	119	+{
	120	+ if (hvc)
	121	+ hvc_remove(hvc);
	122	+}
	123	+
	124	+static int xen_cons_init(void)
	125	+{
	126	+ if (!is_running_on_xen())
	127	+ return 0;
	128	+
	129	+ hvc_instantiate(HVC_COOKIE, 0, &hvc_ops);
	130	+ return 0;
	131	+}
	132	+
	133	+module_init(xen_init);
	134	+module_exit(xen_fini);
	135	+console_initcall(xen_cons_init);
	136	+
	137	+static void xenboot_write_console(struct console console, const char string,
	138	+ unsigned len)
	139	+{
	140	+ unsigned int linelen, off = 0;
	141	+ const char *pos;
	142	+
	143	+ while (off < len && NULL != (pos = strchr(string+off, '\n'))) {
	144	+ linelen = pos-string+off;
	145	+ if (off + linelen > len)
	146	+ break;
	147	+ write_console(0, string+off, linelen);
	148	+ write_console(0, "\r\n", 2);
	149	+ off += linelen + 1;
	150	+ }
	151	+ if (off < len)
	152	+ write_console(0, string+off, len-off);
	153	+}
	154	+
	155	+struct console xenboot_console = {
	156	+ .name = "xenboot",
	157	+ .write = xenboot_write_console,
	158	+ .flags = CON_PRINTBUFFER \| CON_BOOT,
	159	+};
...	...	@@ -13,6 +13,7 @@
13	13	XEN_NR_IPIS,
14	14	};
15	15
	16	+int bind_evtchn_to_irq(unsigned int evtchn);
16	17	int bind_evtchn_to_irqhandler(unsigned int evtchn,
17	18	irq_handler_t handler,
18	19	unsigned long irqflags, const char *devname,
	1	+#ifndef XEN_HVC_CONSOLE_H
	2	+#define XEN_HVC_CONSOLE_H
	3	+
	4	+extern struct console xenboot_console;
	5	+
	6	+#endif /* XEN_HVC_CONSOLE_H */