xref: /freebsd/stand/libsa/tslog.c (revision efe014e6b177ba1b0d70f7df751f5066d4eafe9b)
1 /*-
2  * Copyright (c) 2021 Colin Percival
3  * All rights reserved.
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  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  */
26 
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
29 
30 #include <sys/types.h>
31 
32 #if defined(__amd64__) || defined(__i386__)
33 #include <machine/cpufunc.h>
34 #elif defined(__aarch64__)
35 #include <machine/armreg.h>
36 #endif
37 
38 #include <stand.h>
39 
40 /* Buffer for holding tslog data in string format. */
41 static char * tslog_buf = NULL;
42 static size_t tslog_buflen = 0;
43 static size_t tslog_bufpos = 0;
44 
45 void
46 tslog_setbuf(void * buf, size_t len)
47 {
48 
49 	tslog_buf = (char *)buf;
50 	tslog_buflen = len;
51 	tslog_bufpos = 0;
52 }
53 
54 void
55 tslog_getbuf(void ** buf, size_t * len)
56 {
57 
58 	*buf = (void *)tslog_buf;
59 	*len = tslog_bufpos;
60 }
61 
62 void
63 tslog(const char * type, const char * f, const char * s)
64 {
65 #if defined(__amd64__) || defined(__i386__)
66 	uint64_t tsc = rdtsc();
67 #elif defined(__aarch64__)
68 	uint64_t tsc = READ_SPECIALREG(cntvct_el0);
69 #else
70 	uint64_t tsc = 0;
71 #endif
72 	int len;
73 
74 	/* If we have no buffer, do nothing. */
75 	if (tslog_buf == NULL)
76 		return;
77 
78 	/* Append to existing buffer, if we have enough space. */
79 	len = snprintf(&tslog_buf[tslog_bufpos],
80 	    tslog_buflen - tslog_bufpos, "0x0 %llu %s %s%s%s\n",
81 	    (unsigned long long)tsc, type, f, s ? " " : "", s ? s : "");
82 	if ((len > 0) && (tslog_bufpos + len <= tslog_buflen))
83 		tslog_bufpos += len;
84 }
85