1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * xen console driver interface to hvc_console.c
4 *
5 * (c) 2007 Gerd Hoffmann <kraxel@suse.de>
6 */
7
8 #include <linux/console.h>
9 #include <linux/delay.h>
10 #include <linux/err.h>
11 #include <linux/irq.h>
12 #include <linux/init.h>
13 #include <linux/types.h>
14 #include <linux/list.h>
15 #include <linux/serial_core.h>
16
17 #include <asm/io.h>
18 #include <asm/xen/hypervisor.h>
19
20 #include <xen/xen.h>
21 #include <xen/interface/xen.h>
22 #include <xen/hvm.h>
23 #include <xen/grant_table.h>
24 #include <xen/page.h>
25 #include <xen/events.h>
26 #include <xen/interface/io/console.h>
27 #include <xen/interface/sched.h>
28 #include <xen/hvc-console.h>
29 #include <xen/xenbus.h>
30
31 #include "hvc_console.h"
32
33 #define HVC_COOKIE 0x58656e /* "Xen" in hex */
34
35 struct xencons_info {
36 struct list_head list;
37 struct xenbus_device *xbdev;
38 struct xencons_interface *intf;
39 unsigned int evtchn;
40 XENCONS_RING_IDX out_cons;
41 unsigned int out_cons_same;
42 struct hvc_struct *hvc;
43 int irq;
44 int vtermno;
45 grant_ref_t gntref;
46 spinlock_t ring_lock;
47 };
48
49 static LIST_HEAD(xenconsoles);
50 static DEFINE_SPINLOCK(xencons_lock);
51
52 /* ------------------------------------------------------------------ */
53
54 static bool xen_console_io = false;
55 static int __initdata opt_console_io = -1;
56
parse_xen_console_io(char * arg)57 static int __init parse_xen_console_io(char *arg)
58 {
59 bool val;
60 int ret;
61
62 ret = kstrtobool(arg, &val);
63 if (ret == 0)
64 opt_console_io = (int)val;
65
66 return ret;
67 }
68 early_param("xen_console_io", parse_xen_console_io);
69
vtermno_to_xencons(int vtermno)70 static struct xencons_info *vtermno_to_xencons(int vtermno)
71 {
72 struct xencons_info *entry, *ret = NULL;
73 unsigned long flags;
74
75 spin_lock_irqsave(&xencons_lock, flags);
76 if (list_empty(&xenconsoles)) {
77 spin_unlock_irqrestore(&xencons_lock, flags);
78 return NULL;
79 }
80
81 list_for_each_entry(entry, &xenconsoles, list) {
82 if (entry->vtermno == vtermno) {
83 ret = entry;
84 break;
85 }
86 }
87 spin_unlock_irqrestore(&xencons_lock, flags);
88
89 return ret;
90 }
91
xenbus_devid_to_vtermno(int devid)92 static inline int xenbus_devid_to_vtermno(int devid)
93 {
94 return devid + HVC_COOKIE;
95 }
96
notify_daemon(struct xencons_info * cons)97 static inline void notify_daemon(struct xencons_info *cons)
98 {
99 /* Use evtchn: this is called early, before irq is set up. */
100 notify_remote_via_evtchn(cons->evtchn);
101 }
102
__write_console(struct xencons_info * xencons,const u8 * data,size_t len)103 static ssize_t __write_console(struct xencons_info *xencons,
104 const u8 *data, size_t len)
105 {
106 XENCONS_RING_IDX cons, prod;
107 struct xencons_interface *intf = xencons->intf;
108 unsigned long flags;
109 size_t sent = 0;
110
111 spin_lock_irqsave(&xencons->ring_lock, flags);
112 cons = intf->out_cons;
113 prod = intf->out_prod;
114 mb(); /* update queue values before going on */
115
116 if ((prod - cons) > sizeof(intf->out)) {
117 spin_unlock_irqrestore(&xencons->ring_lock, flags);
118 pr_err_once("xencons: Illegal ring page indices");
119 return -EINVAL;
120 }
121
122 while ((sent < len) && ((prod - cons) < sizeof(intf->out)))
123 intf->out[MASK_XENCONS_IDX(prod++, intf->out)] = data[sent++];
124
125 wmb(); /* write ring before updating pointer */
126 intf->out_prod = prod;
127 spin_unlock_irqrestore(&xencons->ring_lock, flags);
128
129 if (sent)
130 notify_daemon(xencons);
131 return sent;
132 }
133
domU_write_console(uint32_t vtermno,const u8 * data,size_t len)134 static ssize_t domU_write_console(uint32_t vtermno, const u8 *data, size_t len)
135 {
136 struct xencons_info *cons = vtermno_to_xencons(vtermno);
137 size_t ret = len;
138
139 if (cons == NULL)
140 return -EINVAL;
141
142 /*
143 * Make sure the whole buffer is emitted, polling if
144 * necessary. We don't ever want to rely on the hvc daemon
145 * because the most interesting console output is when the
146 * kernel is crippled.
147 */
148 while (len) {
149 ssize_t sent = __write_console(cons, data, len);
150
151 if (sent < 0)
152 return sent;
153
154 data += sent;
155 len -= sent;
156
157 if (unlikely(len))
158 HYPERVISOR_sched_op(SCHEDOP_yield, NULL);
159 }
160
161 return ret;
162 }
163
domU_read_console(uint32_t vtermno,u8 * buf,size_t len)164 static ssize_t domU_read_console(uint32_t vtermno, u8 *buf, size_t len)
165 {
166 struct xencons_interface *intf;
167 XENCONS_RING_IDX cons, prod;
168 struct xencons_info *xencons = vtermno_to_xencons(vtermno);
169 unsigned int eoiflag = 0;
170 unsigned long flags;
171 size_t recv = 0;
172
173 if (xencons == NULL)
174 return -EINVAL;
175 intf = xencons->intf;
176
177 spin_lock_irqsave(&xencons->ring_lock, flags);
178 cons = intf->in_cons;
179 prod = intf->in_prod;
180 mb(); /* get pointers before reading ring */
181
182 if ((prod - cons) > sizeof(intf->in)) {
183 spin_unlock_irqrestore(&xencons->ring_lock, flags);
184 pr_err_once("xencons: Illegal ring page indices");
185 return -EINVAL;
186 }
187
188 while (cons != prod && recv < len)
189 buf[recv++] = intf->in[MASK_XENCONS_IDX(cons++, intf->in)];
190
191 mb(); /* read ring before consuming */
192 intf->in_cons = cons;
193
194 /*
195 * When to mark interrupt having been spurious:
196 * - there was no new data to be read, and
197 * - the backend did not consume some output bytes, and
198 * - the previous round with no read data didn't see consumed bytes
199 * (we might have a race with an interrupt being in flight while
200 * updating xencons->out_cons, so account for that by allowing one
201 * round without any visible reason)
202 */
203 if (intf->out_cons != xencons->out_cons) {
204 xencons->out_cons = intf->out_cons;
205 xencons->out_cons_same = 0;
206 }
207 if (!recv && xencons->out_cons_same++ > 1) {
208 eoiflag = XEN_EOI_FLAG_SPURIOUS;
209 }
210 spin_unlock_irqrestore(&xencons->ring_lock, flags);
211
212 if (recv) {
213 notify_daemon(xencons);
214 }
215
216 xen_irq_lateeoi(xencons->irq, eoiflag);
217
218 return recv;
219 }
220
221 static const struct hv_ops domU_hvc_ops = {
222 .get_chars = domU_read_console,
223 .put_chars = domU_write_console,
224 .notifier_add = notifier_add_irq,
225 .notifier_del = notifier_del_irq,
226 .notifier_hangup = notifier_hangup_irq,
227 };
228
dom0_read_console(uint32_t vtermno,u8 * buf,size_t len)229 static ssize_t dom0_read_console(uint32_t vtermno, u8 *buf, size_t len)
230 {
231 return HYPERVISOR_console_io(CONSOLEIO_read, len, buf);
232 }
233
234 /*
235 * Either for a dom0 to write to the system console, or a domU with a
236 * debug version of Xen
237 */
dom0_write_console(uint32_t vtermno,const u8 * str,size_t len)238 static ssize_t dom0_write_console(uint32_t vtermno, const u8 *str, size_t len)
239 {
240 int rc = HYPERVISOR_console_io(CONSOLEIO_write, len, (u8 *)str);
241 if (rc < 0)
242 return rc;
243
244 return len;
245 }
246
247 static const struct hv_ops dom0_hvc_ops = {
248 .get_chars = dom0_read_console,
249 .put_chars = dom0_write_console,
250 .notifier_add = notifier_add_irq,
251 .notifier_del = notifier_del_irq,
252 .notifier_hangup = notifier_hangup_irq,
253 };
254
xen_hvm_console_init(void)255 static int xen_hvm_console_init(void)
256 {
257 int r;
258 uint64_t v = 0;
259 unsigned long gfn, flags;
260 struct xencons_info *info;
261
262 if (!xen_hvm_domain())
263 return -ENODEV;
264
265 info = vtermno_to_xencons(HVC_COOKIE);
266 if (!info) {
267 info = kzalloc_obj(struct xencons_info);
268 if (!info)
269 return -ENOMEM;
270 spin_lock_init(&info->ring_lock);
271 } else if (info->intf != NULL) {
272 /* already configured */
273 return 0;
274 }
275 /*
276 * If the toolstack (or the hypervisor) hasn't set these values, the
277 * default value is 0. Even though gfn = 0 and evtchn = 0 are
278 * theoretically correct values, in practice they never are and they
279 * mean that a legacy toolstack hasn't initialized the pv console correctly.
280 */
281 r = hvm_get_parameter(HVM_PARAM_CONSOLE_EVTCHN, &v);
282 if (r < 0 || v == 0)
283 goto err;
284 info->evtchn = v;
285 v = 0;
286 r = hvm_get_parameter(HVM_PARAM_CONSOLE_PFN, &v);
287 if (r < 0 || v == 0)
288 goto err;
289 gfn = v;
290 info->intf = memremap(gfn << XEN_PAGE_SHIFT, XEN_PAGE_SIZE, MEMREMAP_WB);
291 if (info->intf == NULL)
292 goto err;
293 info->vtermno = HVC_COOKIE;
294
295 spin_lock_irqsave(&xencons_lock, flags);
296 list_add_tail(&info->list, &xenconsoles);
297 spin_unlock_irqrestore(&xencons_lock, flags);
298
299 return 0;
300 err:
301 kfree(info);
302 return -ENODEV;
303 }
304
xencons_info_pv_init(struct xencons_info * info,int vtermno)305 static int xencons_info_pv_init(struct xencons_info *info, int vtermno)
306 {
307 spin_lock_init(&info->ring_lock);
308 info->evtchn = xen_start_info->console.domU.evtchn;
309 /* GFN == MFN for PV guest */
310 info->intf = gfn_to_virt(xen_start_info->console.domU.mfn);
311 info->vtermno = vtermno;
312
313 list_add_tail(&info->list, &xenconsoles);
314
315 return 0;
316 }
317
xen_pv_console_init(void)318 static int xen_pv_console_init(void)
319 {
320 struct xencons_info *info;
321 unsigned long flags;
322
323 if (!xen_pv_domain())
324 return -ENODEV;
325
326 if (!xen_start_info->console.domU.evtchn)
327 return -ENODEV;
328
329 info = vtermno_to_xencons(HVC_COOKIE);
330 if (!info) {
331 info = kzalloc_obj(struct xencons_info);
332 if (!info)
333 return -ENOMEM;
334 } else if (info->intf != NULL) {
335 /* already configured */
336 return 0;
337 }
338 spin_lock_irqsave(&xencons_lock, flags);
339 xencons_info_pv_init(info, HVC_COOKIE);
340 spin_unlock_irqrestore(&xencons_lock, flags);
341
342 return 0;
343 }
344
xen_initial_domain_console_init(void)345 static int xen_initial_domain_console_init(void)
346 {
347 struct xencons_info *info;
348 unsigned long flags;
349
350 if (!xen_console_io)
351 return -ENODEV;
352
353 info = vtermno_to_xencons(HVC_COOKIE);
354 if (!info) {
355 info = kzalloc_obj(struct xencons_info);
356 if (!info)
357 return -ENOMEM;
358 spin_lock_init(&info->ring_lock);
359 }
360
361 info->irq = bind_virq_to_irq(VIRQ_CONSOLE, 0, false);
362 info->vtermno = HVC_COOKIE;
363
364 spin_lock_irqsave(&xencons_lock, flags);
365 list_add_tail(&info->list, &xenconsoles);
366 spin_unlock_irqrestore(&xencons_lock, flags);
367
368 return 0;
369 }
370
xen_console_update_evtchn(struct xencons_info * info)371 static void xen_console_update_evtchn(struct xencons_info *info)
372 {
373 if (xen_hvm_domain()) {
374 uint64_t v = 0;
375 int err;
376
377 err = hvm_get_parameter(HVM_PARAM_CONSOLE_EVTCHN, &v);
378 if (!err && v)
379 info->evtchn = v;
380 } else
381 info->evtchn = xen_start_info->console.domU.evtchn;
382 }
383
xen_console_resume(void)384 void xen_console_resume(void)
385 {
386 struct xencons_info *info = vtermno_to_xencons(HVC_COOKIE);
387 if (info != NULL && info->irq) {
388 if (!xen_console_io)
389 xen_console_update_evtchn(info);
390 rebind_evtchn_irq(info->evtchn, info->irq);
391 }
392 }
393
394 #ifdef CONFIG_HVC_XEN_FRONTEND
xencons_disconnect_backend(struct xencons_info * info)395 static void xencons_disconnect_backend(struct xencons_info *info)
396 {
397 if (info->hvc != NULL)
398 hvc_remove(info->hvc);
399 info->hvc = NULL;
400 if (info->irq > 0) {
401 evtchn_put(info->evtchn);
402 info->irq = 0;
403 info->evtchn = 0;
404 }
405 /* evtchn_put() will also close it so this is only an error path */
406 if (info->evtchn > 0)
407 xenbus_free_evtchn(info->xbdev, info->evtchn);
408 info->evtchn = 0;
409 if (info->gntref > 0)
410 gnttab_free_grant_references(info->gntref);
411 info->gntref = 0;
412 }
413
xencons_free(struct xencons_info * info)414 static void xencons_free(struct xencons_info *info)
415 {
416 free_page((unsigned long)info->intf);
417 info->intf = NULL;
418 info->vtermno = 0;
419 kfree(info);
420 }
421
xen_console_remove(struct xencons_info * info)422 static int xen_console_remove(struct xencons_info *info)
423 {
424 unsigned long flags;
425
426 xencons_disconnect_backend(info);
427 spin_lock_irqsave(&xencons_lock, flags);
428 list_del(&info->list);
429 spin_unlock_irqrestore(&xencons_lock, flags);
430 if (info->xbdev != NULL)
431 xencons_free(info);
432 else {
433 if (xen_hvm_domain())
434 iounmap(info->intf);
435 kfree(info);
436 }
437 return 0;
438 }
439
xencons_remove(struct xenbus_device * dev)440 static void xencons_remove(struct xenbus_device *dev)
441 {
442 xen_console_remove(dev_get_drvdata(&dev->dev));
443 }
444
xencons_connect_backend(struct xenbus_device * dev,struct xencons_info * info)445 static int xencons_connect_backend(struct xenbus_device *dev,
446 struct xencons_info *info)
447 {
448 int ret, evtchn, devid, ref, irq;
449 struct xenbus_transaction xbt;
450 grant_ref_t gref_head;
451
452 ret = xenbus_alloc_evtchn(dev, &evtchn);
453 if (ret)
454 return ret;
455 info->evtchn = evtchn;
456 irq = bind_evtchn_to_irq_lateeoi(evtchn);
457 if (irq < 0)
458 return irq;
459 info->irq = irq;
460 devid = dev->nodename[strlen(dev->nodename) - 1] - '0';
461 info->hvc = hvc_alloc(xenbus_devid_to_vtermno(devid),
462 irq, &domU_hvc_ops, 256);
463 if (IS_ERR(info->hvc))
464 return PTR_ERR(info->hvc);
465 ret = gnttab_alloc_grant_references(1, &gref_head);
466 if (ret < 0)
467 return ret;
468 info->gntref = gref_head;
469 ref = gnttab_claim_grant_reference(&gref_head);
470 if (ref < 0)
471 return ref;
472 gnttab_grant_foreign_access_ref(ref, info->xbdev->otherend_id,
473 virt_to_gfn(info->intf), 0);
474
475 again:
476 ret = xenbus_transaction_start(&xbt);
477 if (ret) {
478 xenbus_dev_fatal(dev, ret, "starting transaction");
479 return ret;
480 }
481 ret = xenbus_printf(xbt, dev->nodename, "ring-ref", "%d", ref);
482 if (ret)
483 goto error_xenbus;
484 ret = xenbus_printf(xbt, dev->nodename, "port", "%u",
485 evtchn);
486 if (ret)
487 goto error_xenbus;
488 ret = xenbus_transaction_end(xbt, 0);
489 if (ret) {
490 if (ret == -EAGAIN)
491 goto again;
492 xenbus_dev_fatal(dev, ret, "completing transaction");
493 return ret;
494 }
495
496 xenbus_switch_state(dev, XenbusStateInitialised);
497 return 0;
498
499 error_xenbus:
500 xenbus_transaction_end(xbt, 1);
501 xenbus_dev_fatal(dev, ret, "writing xenstore");
502 return ret;
503 }
504
xencons_probe(struct xenbus_device * dev,const struct xenbus_device_id * id)505 static int xencons_probe(struct xenbus_device *dev,
506 const struct xenbus_device_id *id)
507 {
508 int ret, devid;
509 struct xencons_info *info;
510 unsigned long flags;
511
512 devid = dev->nodename[strlen(dev->nodename) - 1] - '0';
513 if (devid == 0)
514 return -ENODEV;
515
516 info = kzalloc_obj(struct xencons_info);
517 if (!info)
518 return -ENOMEM;
519 spin_lock_init(&info->ring_lock);
520 dev_set_drvdata(&dev->dev, info);
521 info->xbdev = dev;
522 info->vtermno = xenbus_devid_to_vtermno(devid);
523 info->intf = (void *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
524 if (!info->intf)
525 goto error_nomem;
526
527 ret = xencons_connect_backend(dev, info);
528 if (ret < 0)
529 goto error;
530 spin_lock_irqsave(&xencons_lock, flags);
531 list_add_tail(&info->list, &xenconsoles);
532 spin_unlock_irqrestore(&xencons_lock, flags);
533
534 return 0;
535
536 error_nomem:
537 ret = -ENOMEM;
538 xenbus_dev_fatal(dev, ret, "allocating device memory");
539 error:
540 xencons_disconnect_backend(info);
541 xencons_free(info);
542 return ret;
543 }
544
xencons_resume(struct xenbus_device * dev)545 static int xencons_resume(struct xenbus_device *dev)
546 {
547 struct xencons_info *info = dev_get_drvdata(&dev->dev);
548
549 xencons_disconnect_backend(info);
550 memset(info->intf, 0, XEN_PAGE_SIZE);
551 return xencons_connect_backend(dev, info);
552 }
553
xencons_backend_changed(struct xenbus_device * dev,enum xenbus_state backend_state)554 static void xencons_backend_changed(struct xenbus_device *dev,
555 enum xenbus_state backend_state)
556 {
557 switch (backend_state) {
558 case XenbusStateReconfiguring:
559 case XenbusStateReconfigured:
560 case XenbusStateInitialising:
561 case XenbusStateInitialised:
562 case XenbusStateUnknown:
563 break;
564
565 case XenbusStateInitWait:
566 break;
567
568 case XenbusStateConnected:
569 xenbus_switch_state(dev, XenbusStateConnected);
570 break;
571
572 case XenbusStateClosed:
573 if (dev->state == XenbusStateClosed)
574 break;
575 fallthrough; /* Missed the backend's CLOSING state */
576 case XenbusStateClosing: {
577 struct xencons_info *info = dev_get_drvdata(&dev->dev);
578
579 /*
580 * Don't tear down the evtchn and grant ref before the other
581 * end has disconnected, but do stop userspace from trying
582 * to use the device before we allow the backend to close.
583 */
584 if (info->hvc) {
585 hvc_remove(info->hvc);
586 info->hvc = NULL;
587 }
588
589 xenbus_frontend_closed(dev);
590 break;
591 }
592 }
593 }
594
595 static const struct xenbus_device_id xencons_ids[] = {
596 { "console" },
597 { "" }
598 };
599
600 static struct xenbus_driver xencons_driver = {
601 .name = "xenconsole",
602 .ids = xencons_ids,
603 .probe = xencons_probe,
604 .remove = xencons_remove,
605 .resume = xencons_resume,
606 .otherend_changed = xencons_backend_changed,
607 .not_essential = true,
608 };
609 #endif /* CONFIG_HVC_XEN_FRONTEND */
610
xen_hvc_init(void)611 static int __init xen_hvc_init(void)
612 {
613 int r;
614 struct xencons_info *info;
615 const struct hv_ops *ops;
616
617 if (!xen_domain())
618 return -ENODEV;
619
620 if (xen_console_io) {
621 ops = &dom0_hvc_ops;
622 r = xen_initial_domain_console_init();
623 if (r < 0)
624 goto register_fe;
625 info = vtermno_to_xencons(HVC_COOKIE);
626 } else {
627 ops = &domU_hvc_ops;
628 if (xen_hvm_domain())
629 r = xen_hvm_console_init();
630 else
631 r = xen_pv_console_init();
632 if (r < 0)
633 goto register_fe;
634
635 info = vtermno_to_xencons(HVC_COOKIE);
636 info->irq = bind_evtchn_to_irq_lateeoi(info->evtchn);
637 }
638 if (info->irq < 0)
639 info->irq = 0; /* NO_IRQ */
640 else
641 irq_set_noprobe(info->irq);
642
643 info->hvc = hvc_alloc(HVC_COOKIE, info->irq, ops, 256);
644 if (IS_ERR(info->hvc)) {
645 unsigned long flags;
646
647 r = PTR_ERR(info->hvc);
648 spin_lock_irqsave(&xencons_lock, flags);
649 list_del(&info->list);
650 spin_unlock_irqrestore(&xencons_lock, flags);
651 if (info->irq)
652 evtchn_put(info->evtchn);
653 kfree(info);
654 return r;
655 }
656
657 r = 0;
658 register_fe:
659 #ifdef CONFIG_HVC_XEN_FRONTEND
660 r = xenbus_register_frontend(&xencons_driver);
661 #endif
662 return r;
663 }
664 device_initcall(xen_hvc_init);
665
xen_cons_init(void)666 static int __init xen_cons_init(void)
667 {
668 const struct hv_ops *ops;
669
670 xen_console_io = opt_console_io >= 0 ? opt_console_io :
671 xen_initial_domain();
672
673 if (!xen_domain())
674 return 0;
675
676 if (xen_console_io)
677 ops = &dom0_hvc_ops;
678 else {
679 int r;
680 ops = &domU_hvc_ops;
681
682 if (xen_hvm_domain())
683 r = xen_hvm_console_init();
684 else
685 r = xen_pv_console_init();
686 if (r < 0)
687 return r;
688 }
689
690 hvc_instantiate(HVC_COOKIE, 0, ops);
691 return 0;
692 }
693 console_initcall(xen_cons_init);
694
695 #ifdef CONFIG_X86
xen_hvm_early_write(uint32_t vtermno,const char * str,int len)696 static void xen_hvm_early_write(uint32_t vtermno, const char *str, int len)
697 {
698 if (xen_cpuid_base())
699 outsb(0xe9, str, len);
700 }
701 #else
xen_hvm_early_write(uint32_t vtermno,const char * str,int len)702 static void xen_hvm_early_write(uint32_t vtermno, const char *str, int len) { }
703 #endif
704
705 #ifdef CONFIG_EARLY_PRINTK
xenboot_console_setup(struct console * console,char * string)706 static int __init xenboot_console_setup(struct console *console, char *string)
707 {
708 static struct xencons_info xenboot;
709
710 if (xen_initial_domain() || !xen_pv_domain())
711 return 0;
712
713 return xencons_info_pv_init(&xenboot, 0);
714 }
715
xenboot_write_console(struct console * console,const char * string,unsigned len)716 static void xenboot_write_console(struct console *console, const char *string,
717 unsigned len)
718 {
719 unsigned int linelen, off = 0;
720 const char *pos;
721
722 if (dom0_write_console(0, string, len) >= 0)
723 return;
724
725 if (!xen_pv_domain()) {
726 xen_hvm_early_write(0, string, len);
727 return;
728 }
729
730 if (domU_write_console(0, "(early) ", 8) < 0)
731 return;
732 while (off < len && NULL != (pos = strchr(string+off, '\n'))) {
733 linelen = pos-string+off;
734 if (off + linelen > len)
735 break;
736 domU_write_console(0, string+off, linelen);
737 domU_write_console(0, "\r\n", 2);
738 off += linelen + 1;
739 }
740 if (off < len)
741 domU_write_console(0, string+off, len-off);
742 }
743
744 struct console xenboot_console = {
745 .name = "xenboot",
746 .write = xenboot_write_console,
747 .setup = xenboot_console_setup,
748 .flags = CON_PRINTBUFFER | CON_BOOT | CON_ANYTIME,
749 .index = -1,
750 };
751 #endif /* CONFIG_EARLY_PRINTK */
752
xen_raw_console_write(const char * str)753 void xen_raw_console_write(const char *str)
754 {
755 ssize_t len = strlen(str);
756 int rc = 0;
757
758 if (xen_domain()) {
759 rc = dom0_write_console(0, str, len);
760 if (rc != -ENOSYS || !xen_hvm_domain())
761 return;
762 }
763 xen_hvm_early_write(0, str, len);
764 }
765
xen_raw_printk(const char * fmt,...)766 void xen_raw_printk(const char *fmt, ...)
767 {
768 static char buf[512];
769 va_list ap;
770
771 va_start(ap, fmt);
772 vsnprintf(buf, sizeof(buf), fmt, ap);
773 va_end(ap);
774
775 xen_raw_console_write(buf);
776 }
777
xenboot_earlycon_write(struct console * console,const char * string,unsigned len)778 static void xenboot_earlycon_write(struct console *console,
779 const char *string,
780 unsigned len)
781 {
782 dom0_write_console(0, string, len);
783 }
784
xenboot_earlycon_setup(struct earlycon_device * device,const char * opt)785 static int __init xenboot_earlycon_setup(struct earlycon_device *device,
786 const char *opt)
787 {
788 device->con->write = xenboot_earlycon_write;
789 return 0;
790 }
791 EARLYCON_DECLARE(xenboot, xenboot_earlycon_setup);
792