xref: /freebsd/stand/libsa/tslog.c (revision 43a5ec4eb41567cc92586503212743d89686d78f)
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 static size_t
46 tsccat(char * buf, uint64_t tsc)
47 {
48 	size_t len;
49 
50 	/* Handle upper digits. */
51 	if (tsc >= 10)
52 		len = tsccat(buf, tsc / 10);
53 	else
54 		len = 0;
55 
56 	/* Write the last digit. */
57 	buf[len] = "0123456789"[tsc % 10];
58 
59 	/* Return the length written. */
60 	return (len + 1);
61 }
62 
63 void
64 tslog_setbuf(void * buf, size_t len)
65 {
66 
67 	tslog_buf = (char *)buf;
68 	tslog_buflen = len;
69 	tslog_bufpos = 0;
70 }
71 
72 void
73 tslog_getbuf(void ** buf, size_t * len)
74 {
75 
76 	*buf = (void *)tslog_buf;
77 	*len = tslog_bufpos;
78 }
79 
80 void
81 tslog(const char * type, const char * f, const char * s)
82 {
83 #if defined(__amd64__) || defined(__i386__)
84 	uint64_t tsc = rdtsc();
85 #elif defined(__aarch64__)
86 	uint64_t tsc = READ_SPECIALREG(cntvct_el0);
87 #else
88 	uint64_t tsc = 0;
89 #endif
90 
91 	/* If we have no buffer, do nothing. */
92 	if (tslog_buf == NULL)
93 		return;
94 
95 	/* Check that we have enough space. */
96 	if (tslog_buflen - tslog_bufpos < 32 + strlen(type) + strlen(f) +
97 	    (s ? strlen(s) : 0))
98 		return;
99 
100 	/* Append to existing buffer. */
101 	strcpy(&tslog_buf[tslog_bufpos], "0x0 ");
102 	tslog_bufpos += 4;
103 	tslog_bufpos += tsccat(&tslog_buf[tslog_bufpos], tsc);
104 	strcpy(&tslog_buf[tslog_bufpos], " ");
105 	tslog_bufpos += 1;
106 	strcpy(&tslog_buf[tslog_bufpos], type);
107 	tslog_bufpos += strlen(type);
108 	strcpy(&tslog_buf[tslog_bufpos], " ");
109 	tslog_bufpos += 1;
110 	strcpy(&tslog_buf[tslog_bufpos], f);
111 	tslog_bufpos += strlen(f);
112 	if (s != NULL) {
113 		strcpy(&tslog_buf[tslog_bufpos], " ");
114 		tslog_bufpos += 1;
115 		strcpy(&tslog_buf[tslog_bufpos], s);
116 		tslog_bufpos += strlen(s);
117 	}
118 	strcpy(&tslog_buf[tslog_bufpos], "\n");
119 	tslog_bufpos += 1;
120 }
121