1 /*- 2 * Copyright (c) 2017 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/param.h> 31 #include <sys/kernel.h> 32 #include <sys/linker.h> 33 #include <sys/sbuf.h> 34 #include <sys/sysctl.h> 35 #include <sys/systm.h> 36 #include <sys/tslog.h> 37 38 #include <machine/atomic.h> 39 #include <machine/cpu.h> 40 41 #ifndef TSLOGSIZE 42 #define TSLOGSIZE 262144 43 #endif 44 45 static volatile long nrecs = 0; 46 static struct timestamp { 47 void * td; 48 int type; 49 const char * f; 50 const char * s; 51 uint64_t tsc; 52 } timestamps[TSLOGSIZE]; 53 54 void 55 tslog(void * td, int type, const char * f, const char * s) 56 { 57 uint64_t tsc = get_cyclecount(); 58 long pos; 59 60 /* Grab a slot. */ 61 pos = atomic_fetchadd_long(&nrecs, 1); 62 63 /* Store record. */ 64 if (pos < nitems(timestamps)) { 65 timestamps[pos].td = td; 66 timestamps[pos].type = type; 67 timestamps[pos].f = f; 68 timestamps[pos].s = s; 69 timestamps[pos].tsc = tsc; 70 } 71 } 72 73 static int 74 sysctl_debug_tslog(SYSCTL_HANDLER_ARGS) 75 { 76 int error; 77 struct sbuf *sb; 78 size_t i, limit; 79 caddr_t loader_tslog; 80 void * loader_tslog_buf; 81 size_t loader_tslog_len; 82 83 /* 84 * This code can race against the code in tslog() which stores 85 * records: Theoretically we could end up reading a record after 86 * its slots have been reserved but before it has been written. 87 * Since this code takes orders of magnitude longer to run than 88 * tslog() takes to write a record, it is highly unlikely that 89 * anyone will ever experience this race. 90 */ 91 sb = sbuf_new_for_sysctl(NULL, NULL, 1024, req); 92 93 /* Get data from the boot loader, if it provided any. */ 94 loader_tslog = preload_search_by_type("TSLOG data"); 95 if (loader_tslog != NULL) { 96 loader_tslog_buf = preload_fetch_addr(loader_tslog); 97 loader_tslog_len = preload_fetch_size(loader_tslog); 98 sbuf_bcat(sb, loader_tslog_buf, loader_tslog_len); 99 } 100 101 /* Add data logged within the kernel. */ 102 limit = MIN(nrecs, nitems(timestamps)); 103 for (i = 0; i < limit; i++) { 104 sbuf_printf(sb, "%p", timestamps[i].td); 105 sbuf_printf(sb, " %llu", 106 (unsigned long long)timestamps[i].tsc); 107 switch (timestamps[i].type) { 108 case TS_ENTER: 109 sbuf_printf(sb, " ENTER"); 110 break; 111 case TS_EXIT: 112 sbuf_printf(sb, " EXIT"); 113 break; 114 case TS_THREAD: 115 sbuf_printf(sb, " THREAD"); 116 break; 117 case TS_EVENT: 118 sbuf_printf(sb, " EVENT"); 119 break; 120 } 121 sbuf_printf(sb, " %s", timestamps[i].f ? timestamps[i].f : "(null)"); 122 if (timestamps[i].s) 123 sbuf_printf(sb, " %s\n", timestamps[i].s); 124 else 125 sbuf_printf(sb, "\n"); 126 } 127 error = sbuf_finish(sb); 128 sbuf_delete(sb); 129 return (error); 130 } 131 132 SYSCTL_PROC(_debug, OID_AUTO, tslog, CTLTYPE_STRING|CTLFLAG_RD|CTLFLAG_MPSAFE, 133 0, 0, sysctl_debug_tslog, "", "Dump recorded event timestamps"); 134