xref: /illumos-gate/usr/src/uts/common/os/console.c (revision fc8ae2ec)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 #include <sys/types.h>
28 #include <sys/varargs.h>
29 #include <sys/modctl.h>
30 #include <sys/cmn_err.h>
31 #include <sys/console.h>
32 #include <sys/consdev.h>
33 #include <sys/promif.h>
34 #include <sys/note.h>
35 #include <sys/polled_io.h>
36 #include <sys/systm.h>
37 #include <sys/file.h>
38 #include <sys/conf.h>
39 #include <sys/kmem.h>
40 #include <sys/taskq.h>
41 #include <sys/log.h>
42 #include <sys/ddi.h>
43 #include <sys/sunddi.h>
44 #include <sys/esunddi.h>
45 #include <sys/fs/snode.h>
46 #include <sys/termios.h>
47 #include <sys/tem_impl.h>
48 
49 #define	MINLINES	10
50 #define	MAXLINES	48
51 #define	LOSCREENLINES	34
52 #define	HISCREENLINES	48
53 
54 #define	MINCOLS		10
55 #define	MAXCOLS		120
56 #define	LOSCREENCOLS	80
57 #define	HISCREENCOLS	120
58 
59 vnode_t *console_vnode;
60 taskq_t *console_taskq;
61 
62 /*
63  * The current set of polled I/O routines (if any)
64  */
65 struct cons_polledio *cons_polledio;
66 
67 /*
68  * Console I/O Routines
69  *
70  * In the event that kernel messages are generated with cmn_err(9F) or printf()
71  * early in boot, after a panic, in resource-constrained situations, or sent
72  * through /dev/console to the wscons driver, we may be called upon to render
73  * characters directly to the frame buffer using the underlying prom_*()
74  * routines.  These in turn may attempt to use PROM services directly, or may
75  * use a kernel console emulator if one is available.  Unfortunately, if PROM
76  * services are being used by the kernel on a multi-CPU system, these routines
77  * might be called while another CPU is simultaneously accessing a frame buffer
78  * memory mapping (perhaps through the X server).  This situation may not be
79  * supported by the frame buffer hardware.
80  *
81  * To handle this situation, we implement a two-phase locking scheme which we
82  * use to protect accesses to the underlying prom_*() rendering routines.  The
83  * common-code functions console_hold() and console_rele() are used to gain
84  * exclusive access to the console from within the kernel.  We use a standard
85  * r/w lock in writer-mode only to implement the kernel lock.  We use an r/w
86  * lock instead of a mutex here because character rendering is slow and hold
87  * times will be relatively long, and there is no point in adaptively spinning.
88  * These routines may be called recursively, in which case subsequent calls
89  * just increment the console_depth hold count.  Once exclusive access is
90  * gained, we grab the frame buffer device node and block further mappings to
91  * it by holding the specfs node lock and the device node's lock.  We then
92  * observe if any mappings are present by examining the specfs node's s_mapcnt
93  * (non-clone mmaps) and the devinfo node's devi_ref count (clone opens).
94  *
95  * Then, around each character rendering call, the routines console_enter()
96  * and console_exit() are used to inform the platform code that we are
97  * accessing the character rendering routines.  These platform routines can
98  * then examine the "busy" flag returned by console_enter() and briefly stop
99  * the other CPUs so that they cannot access the frame buffer hardware while
100  * we are busy rendering characters.  This mess can all be removed when the
101  * impossible dream of a unified kernel console emulator is someday realized.
102  */
103 
104 static krwlock_t console_lock;
105 static uint_t console_depth;
106 static int console_busy;
107 
108 extern void pm_cfb_check_and_powerup(void);
109 extern void pm_cfb_rele(void);
110 
111 static int
console_hold(void)112 console_hold(void)
113 {
114 	if (panicstr != NULL)
115 		return (console_busy); /* assume exclusive access in panic */
116 
117 	if (rw_owner(&console_lock) != curthread)
118 		rw_enter(&console_lock, RW_WRITER);
119 
120 	if (console_depth++ != 0)
121 		return (console_busy); /* lock is being entered recursively */
122 
123 	pm_cfb_check_and_powerup();
124 
125 #ifdef _HAVE_TEM_FIRMWARE
126 	if (consmode == CONS_FW && ncpus > 1 && fbvp != NULL) {
127 		struct snode *csp = VTOS(VTOS(fbvp)->s_commonvp);
128 
129 		mutex_enter(&csp->s_lock);
130 		console_busy = csp->s_mapcnt != 0;
131 
132 		if (csp->s_mapcnt == 0 && fbdip != NULL) {
133 			mutex_enter(&DEVI(fbdip)->devi_lock);
134 			console_busy = DEVI(fbdip)->devi_ref != 0;
135 		}
136 	}
137 #endif /* _HAVE_TEM_FIRMWARE */
138 	return (console_busy);
139 }
140 
141 static void
console_rele(void)142 console_rele(void)
143 {
144 	if (panicstr != NULL)
145 		return; /* do not modify lock states if we are panicking */
146 
147 	ASSERT(RW_WRITE_HELD(&console_lock));
148 	ASSERT(console_depth != 0);
149 
150 	if (--console_depth != 0)
151 		return; /* lock is being dropped recursively */
152 
153 #ifdef _HAVE_TEM_FIRMWARE
154 	if (consmode == CONS_FW && ncpus > 1 && fbvp != NULL) {
155 		struct snode *csp = VTOS(VTOS(fbvp)->s_commonvp);
156 
157 		ASSERT(MUTEX_HELD(&csp->s_lock));
158 		if (csp->s_mapcnt == 0 && fbdip != NULL)
159 			mutex_exit(&DEVI(fbdip)->devi_lock);
160 
161 		mutex_exit(&csp->s_lock);
162 	}
163 #endif /* _HAVE_TEM_FIRMWARE */
164 	pm_cfb_rele();
165 	console_busy = 0;
166 	rw_exit(&console_lock);
167 }
168 
169 static void
console_getprop(dev_t dev,dev_info_t * dip,char * name,ushort_t * sp)170 console_getprop(dev_t dev, dev_info_t *dip, char *name, ushort_t *sp)
171 {
172 	uchar_t *data;
173 	uint_t len;
174 	uint_t i;
175 
176 	*sp = 0;
177 	if (ddi_prop_lookup_byte_array(dev, dip, 0, name, &data, &len) ==
178 	    DDI_PROP_SUCCESS) {
179 		for (i = 0; i < len; i++) {
180 			if (data[i] < '0' || data[i] > '9')
181 				break;
182 			*sp = *sp * 10 + data[i] - '0';
183 		}
184 		ddi_prop_free(data);
185 	}
186 }
187 
188 /*
189  * Gets the number of rows and columns (in char's) and the
190  * width and height (in pixels) of the console.
191  */
192 void
console_get_size(ushort_t * r,ushort_t * c,ushort_t * x,ushort_t * y)193 console_get_size(ushort_t *r, ushort_t *c, ushort_t *x, ushort_t *y)
194 {
195 	int rel_needed = 0;
196 	dev_info_t *dip;
197 	dev_t dev;
198 
199 	/*
200 	 * If we have loaded the console IO stuff, then ask for the screen
201 	 * size properties from the layered terminal emulator.  Else ask for
202 	 * them from the root node, which will eventually fall through to the
203 	 * options node and get them from the prom.
204 	 */
205 	if (rwsconsvp == NULL || consmode == CONS_FW) {
206 		dip = ddi_root_node();
207 		dev = DDI_DEV_T_ANY;
208 	} else {
209 		dev = rwsconsvp->v_rdev; /* layering is wc -> tem */
210 		dip = e_ddi_hold_devi_by_dev(dev, 0);
211 		rel_needed = 1;
212 	}
213 
214 	/*
215 	 * If we have not initialized a console yet and don't have a root
216 	 * node (ie. we have not initialized the DDI yet) return our default
217 	 * size for the screen.
218 	 */
219 	if (dip == NULL) {
220 		*r = LOSCREENLINES;
221 		*c = LOSCREENCOLS;
222 		*x = *y = 0;
223 		return;
224 	}
225 
226 	console_getprop(DDI_DEV_T_ANY, dip, "screen-#columns", c);
227 	console_getprop(DDI_DEV_T_ANY, dip, "screen-#rows", r);
228 	console_getprop(DDI_DEV_T_ANY, dip, "screen-width", x);
229 	console_getprop(DDI_DEV_T_ANY, dip, "screen-height", y);
230 
231 	if (*c < MINCOLS)
232 		*c = LOSCREENCOLS;
233 	else if (*c > MAXCOLS)
234 		*c = HISCREENCOLS;
235 
236 	if (*r < MINLINES)
237 		*r = LOSCREENLINES;
238 	else if (*r > MAXLINES)
239 		*r = HISCREENLINES;
240 
241 	if (rel_needed)
242 		ddi_release_devi(dip);
243 }
244 
245 typedef struct console_msg {
246 	size_t	cm_size;
247 	char	cm_text[1];
248 } console_msg_t;
249 
250 /*
251  * If we can't access the console stream, fall through to PROM, which redirects
252  * it back into to terminal emulator as appropriate.  The console stream should
253  * be available after consconfig runs.
254  */
255 static void
console_putmsg(console_msg_t * cm)256 console_putmsg(console_msg_t *cm)
257 {
258 	int busy, spl;
259 	ssize_t res;
260 
261 	ASSERT(taskq_member(console_taskq, curthread));
262 
263 	if (rconsvp == NULL || panicstr ||
264 	    vn_rdwr(UIO_WRITE, console_vnode, cm->cm_text, strlen(cm->cm_text),
265 	    0, UIO_SYSSPACE, FAPPEND, (rlim64_t)LOG_HIWAT, kcred, &res) != 0) {
266 
267 		busy = console_hold();
268 		spl = console_enter(busy);
269 
270 		prom_printf("%s", cm->cm_text);
271 
272 		console_exit(busy, spl);
273 		console_rele();
274 	}
275 
276 	kmem_free(cm, cm->cm_size);
277 }
278 
279 void
console_vprintf(const char * fmt,va_list adx)280 console_vprintf(const char *fmt, va_list adx)
281 {
282 	console_msg_t *cm;
283 	size_t len = vsnprintf(NULL, 0, fmt, adx);
284 	int busy, spl;
285 
286 	if (console_taskq != NULL && rconsvp != NULL && panicstr == NULL &&
287 	    (cm = kmem_alloc(sizeof (*cm) + len, KM_NOSLEEP)) != NULL) {
288 		cm->cm_size = sizeof (*cm) + len;
289 		(void) vsnprintf(cm->cm_text, len + 1, fmt, adx);
290 		if (taskq_dispatch(console_taskq, (task_func_t *)console_putmsg,
291 		    cm, TQ_NOSLEEP) != TASKQID_INVALID)
292 			return;
293 		kmem_free(cm, cm->cm_size);
294 	}
295 
296 	busy = console_hold();
297 	spl = console_enter(busy);
298 
299 	prom_vprintf(fmt, adx);
300 
301 	console_exit(busy, spl);
302 	console_rele();
303 }
304 
305 /*PRINTFLIKE1*/
306 void
console_printf(const char * fmt,...)307 console_printf(const char *fmt, ...)
308 {
309 	va_list adx;
310 
311 	va_start(adx, fmt);
312 	console_vprintf(fmt, adx);
313 	va_end(adx);
314 }
315 
316 /*
317  * Avoid calling this function.
318  *
319  * Nothing in the kernel besides the wscons driver (wc) uses this
320  * function. It may hopefully one day be removed altogether.
321  * If a wayward module calls this they will pass through to PROM,
322  * get redirected into the kernel emulator as appropriate.
323  */
324 void
console_puts(const char * s,size_t n)325 console_puts(const char *s, size_t n)
326 {
327 	int busy, spl;
328 
329 	busy = console_hold();
330 	spl = console_enter(busy);
331 
332 	prom_writestr(s, n);
333 
334 	console_exit(busy, spl);
335 	console_rele();
336 }
337 
338 /*
339  * Let this function just go straight through to the PROM, since
340  * we are called in early boot prior to the kernel terminal
341  * emulator being available, and prior to the PROM stdout redirect
342  * vector being set.
343  */
344 static void
console_putc(int c)345 console_putc(int c)
346 {
347 	int busy = console_hold();
348 	int spl = console_enter(busy);
349 
350 	if (c == '\n')
351 		prom_putchar('\r');
352 	prom_putchar(c);
353 
354 	console_exit(busy, spl);
355 	console_rele();
356 }
357 
358 /*
359  * Read a string from the console device.  We only permit synchronous
360  * conversation between the kernel and a console user early in boot prior to
361  * the initialization of rconsvp.
362  */
363 void
console_gets(char * s,size_t len)364 console_gets(char *s, size_t len)
365 {
366 	char *p = s;
367 	char *q = s + len - 1;
368 	int c;
369 
370 	ASSERT(rconsvp == NULL);
371 	(void) console_hold();
372 
373 	for (;;) {
374 		switch (c = (prom_getchar() & 0x7f)) {
375 		case 0x7f: /* DEL */
376 			if (p == s)
377 				break;
378 			console_putc(c);
379 			c = '\b';
380 			/*FALLTHRU*/
381 
382 		case '\b':
383 			if (p == s)
384 				break;
385 			console_putc('\b');
386 			console_putc(' ');
387 			/*FALLTHRU*/
388 
389 		case '#': /* historical backspace alias */
390 			console_putc(c);
391 			if (p > s)
392 				p--;
393 			break;
394 
395 		case CTRL('u'):
396 			console_putc(c);
397 			console_putc('\n');
398 			p = s;
399 			break;
400 
401 		case '\r':
402 		case '\n':
403 			console_putc('\n');
404 			goto done;
405 
406 		default:
407 			if (p < q) {
408 				console_putc(c);
409 				*p++ = c;
410 			} else
411 				console_putc('\a');
412 		}
413 	}
414 done:
415 	console_rele();
416 	*p = '\0';
417 }
418 
419 /*
420  * Read a character from the console device.  Synchronous conversation between
421  * the kernel and a console user is only permitted early in boot prior to the
422  * initialization of rconsvp.
423  */
424 int
console_getc(void)425 console_getc(void)
426 {
427 	int c;
428 
429 	ASSERT(rconsvp == NULL);
430 	c = prom_getchar();
431 
432 	if (c == '\r')
433 		c = '\n';
434 
435 	console_putc(c);
436 	return (c);
437 }
438