xref: /freebsd/stand/libsa/tslog.c (revision 2e3f49888ec8851bafb22011533217487764fdb0)
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/types.h>
28 
29 #if defined(__amd64__) || defined(__i386__)
30 #include <machine/cpufunc.h>
31 #elif defined(__aarch64__)
32 #include <machine/armreg.h>
33 #endif
34 
35 #include <stand.h>
36 
37 /* Buffer for holding tslog data in string format. */
38 static char * tslog_buf = NULL;
39 static size_t tslog_buflen = 0;
40 static size_t tslog_bufpos = 0;
41 
42 static size_t
43 tsccat(char * buf, uint64_t tsc)
44 {
45 	size_t len;
46 
47 	/* Handle upper digits. */
48 	if (tsc >= 10)
49 		len = tsccat(buf, tsc / 10);
50 	else
51 		len = 0;
52 
53 	/* Write the last digit. */
54 	buf[len] = "0123456789"[tsc % 10];
55 
56 	/* Return the length written. */
57 	return (len + 1);
58 }
59 
60 void
61 tslog_setbuf(void * buf, size_t len)
62 {
63 
64 	tslog_buf = (char *)buf;
65 	tslog_buflen = len;
66 	tslog_bufpos = 0;
67 }
68 
69 void
70 tslog_getbuf(void ** buf, size_t * len)
71 {
72 
73 	*buf = (void *)tslog_buf;
74 	*len = tslog_bufpos;
75 }
76 
77 void
78 tslog(const char * type, const char * f, const char * s)
79 {
80 #if defined(__amd64__) || defined(__i386__)
81 	uint64_t tsc = rdtsc();
82 #elif defined(__aarch64__)
83 	uint64_t tsc = READ_SPECIALREG(cntvct_el0);
84 #else
85 	uint64_t tsc = 0;
86 #endif
87 
88 	/* If we have no buffer, do nothing. */
89 	if (tslog_buf == NULL)
90 		return;
91 
92 	/* Check that we have enough space. */
93 	if (tslog_buflen - tslog_bufpos < 32 + strlen(type) + strlen(f) +
94 	    (s ? strlen(s) : 0))
95 		return;
96 
97 	/* Append to existing buffer. */
98 	strcpy(&tslog_buf[tslog_bufpos], "0x0 ");
99 	tslog_bufpos += 4;
100 	tslog_bufpos += tsccat(&tslog_buf[tslog_bufpos], tsc);
101 	strcpy(&tslog_buf[tslog_bufpos], " ");
102 	tslog_bufpos += 1;
103 	strcpy(&tslog_buf[tslog_bufpos], type);
104 	tslog_bufpos += strlen(type);
105 	strcpy(&tslog_buf[tslog_bufpos], " ");
106 	tslog_bufpos += 1;
107 	strcpy(&tslog_buf[tslog_bufpos], f);
108 	tslog_bufpos += strlen(f);
109 	if (s != NULL) {
110 		strcpy(&tslog_buf[tslog_bufpos], " ");
111 		tslog_bufpos += 1;
112 		strcpy(&tslog_buf[tslog_bufpos], s);
113 		tslog_bufpos += strlen(s);
114 	}
115 	strcpy(&tslog_buf[tslog_bufpos], "\n");
116 	tslog_bufpos += 1;
117 }
118