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DEFINITIONS
This source file includes following definitions.
- kprintf_bootstrap
- console_send
- kprintf
- panic
- badassert
1 /*
2 * Copyright (c) 2000, 2001, 2002, 2003, 2004, 2005, 2008, 2009
3 * The President and Fellows of Harvard College.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. Neither the name of the University nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE UNIVERSITY AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE UNIVERSITY OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30 #include <types.h>
31 #include <kern/unistd.h>
32 #include <stdarg.h>
33 #include <lib.h>
34 #include <spl.h>
35 #include <thread.h>
36 #include <current.h>
37 #include <synch.h>
38 #include <mainbus.h>
39 #include <vfs.h> // for vfs_sync()
40
41
42 /* Flags word for DEBUG() macro. */
43 uint32_t dbflags = 0;
44
45 /* Lock for non-polled kprintfs */
46 static struct lock *kprintf_lock;
47
48 /* Lock for polled kprintfs */
49 static struct spinlock kprintf_spinlock;
50
51
52 /*
53 * Warning: all this has to work from interrupt handlers and when
54 * interrupts are disabled.
55 */
56
57
58 /*
59 * Create the kprintf lock. Must be called before creating a second
60 * thread or enabling a second CPU.
61 */
62 void
63 kprintf_bootstrap(void)
64 {
65 KASSERT(kprintf_lock == NULL);
66
67 kprintf_lock = lock_create("kprintf_lock");
68 if (kprintf_lock == NULL) {
69 panic("Could not create kprintf_lock\n");
70 }
71 spinlock_init(&kprintf_spinlock);
72 }
73
74 /*
75 * Send characters to the console. Backend for __printf.
76 */
77 static
78 void
79 console_send(void *junk, const char *data, size_t len)
80 {
81 size_t i;
82
83 (void)junk;
84
85 for (i=0; i<len; i++) {
86 putch(data[i]);
87 }
88 }
89
90 /*
91 * Printf to the console.
92 */
93 int
94 kprintf(const char *fmt, ...)
95 {
96 int chars;
97 va_list ap;
98 bool dolock;
99
100 dolock = kprintf_lock != NULL
101 && curthread->t_in_interrupt == false
102 && curthread->t_iplhigh_count == 0;
103
104 if (dolock) {
105 lock_acquire(kprintf_lock);
106 }
107 else {
108 spinlock_acquire(&kprintf_spinlock);
109 }
110 putch_prepare();
111
112 va_start(ap, fmt);
113 chars = __vprintf(console_send, NULL, fmt, ap);
114 va_end(ap);
115
116 putch_complete();
117 if (dolock) {
118 lock_release(kprintf_lock);
119 }
120 else {
121 spinlock_release(&kprintf_spinlock);
122 }
123
124 return chars;
125 }
126
127 /*
128 * panic() is for fatal errors. It prints the printf arguments it's
129 * passed and then halts the system.
130 */
131
132 void
133 panic(const char *fmt, ...)
134 {
135 va_list ap;
136
137 /*
138 * When we reach panic, the system is usually fairly screwed up.
139 * It's not entirely uncommon for anything else we try to do
140 * here to trigger more panics.
141 *
142 * This variable makes sure that if we try to do something here,
143 * and it causes another panic, *that* panic doesn't try again;
144 * trying again almost inevitably causes infinite recursion.
145 *
146 * This is not excessively paranoid - these things DO happen!
147 */
148 static volatile int evil;
149
150 if (evil == 0) {
151 evil = 1;
152
153 /*
154 * Not only do we not want to be interrupted while
155 * panicking, but we also want the console to be
156 * printing in polling mode so as not to do context
157 * switches. So turn interrupts off on this CPU.
158 */
159 splhigh();
160 }
161
162 if (evil == 1) {
163 evil = 2;
164
165 /* Kill off other threads and halt other CPUs. */
166 thread_panic();
167 }
168
169 if (evil == 2) {
170 evil = 3;
171
172 /* Print the message. */
173 kprintf("panic: ");
174 putch_prepare();
175 va_start(ap, fmt);
176 __vprintf(console_send, NULL, fmt, ap);
177 va_end(ap);
178 putch_complete();
179 }
180
181 if (evil == 3) {
182 evil = 4;
183
184 /* Try to sync the disks. */
185 vfs_sync();
186 }
187
188 if (evil == 4) {
189 evil = 5;
190
191 /* Shut down or reboot the system. */
192 mainbus_panic();
193 }
194
195 /*
196 * Last resort, just in case.
197 */
198
199 for (;;);
200 }
201
202 /*
203 * Assertion failures go through this.
204 */
205 void
206 badassert(const char *expr, const char *file, int line, const char *func)
207 {
208 panic("Assertion failed: %s, at %s:%d (%s)\n",
209 expr, file, line, func);
210 }