1 /* $NetBSD: t_spinlock.c,v 1.4 2022/08/12 11:21:44 riastradh Exp $ */ 2 3 /*- 4 * Copyright (c) 2022 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 17 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 18 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 19 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 20 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 26 * POSSIBILITY OF SUCH DAMAGE. 27 */ 28 29 #include <sys/cdefs.h> 30 __RCSID("$NetBSD: t_spinlock.c,v 1.4 2022/08/12 11:21:44 riastradh Exp $"); 31 32 #include <sys/types.h> 33 34 #include <sys/atomic.h> 35 #include <sys/param.h> 36 #include <sys/sysctl.h> 37 38 #include <assert.h> 39 #include <atf-c.h> 40 #include <err.h> 41 #include <errno.h> 42 #include <inttypes.h> 43 #include <pthread.h> 44 #include <stdint.h> 45 #include <stdio.h> 46 #include <unistd.h> 47 48 #ifdef BROKEN_ACQUIRE 49 #undef membar_acquire 50 #define membar_acquire() asm volatile("" ::: "memory") 51 #endif /* BROKEN_ACQUIRE */ 52 53 #ifdef BROKEN_RELEASE 54 #undef membar_release 55 #define membar_release() asm volatile("" ::: "memory") 56 #endif /* BROKEN_RELEASE */ 57 58 volatile sig_atomic_t times_up; 59 60 volatile unsigned lockbit __aligned(COHERENCY_UNIT); 61 62 volatile struct { 63 uint64_t v; 64 } __aligned(COHERENCY_UNIT) C[8]; 65 uint64_t TC[2]; 66 67 static void 68 lock(void) 69 { 70 71 while (atomic_swap_uint(&lockbit, 1)) 72 continue; 73 membar_acquire(); 74 } 75 76 static void 77 unlock(void) 78 { 79 80 membar_release(); 81 #ifdef __HAVE_HASHLOCKED_ATOMICS 82 (void)atomic_cas_uint(&lockbit, 1, 0); 83 #else 84 lockbit = 0; 85 #endif 86 } 87 88 static void * 89 thread(void *cookie) 90 { 91 unsigned me = (unsigned)(uintptr_t)cookie; 92 uint64_t C_local = 0, C0[__arraycount(C)]; 93 unsigned i; 94 95 while (!times_up) { 96 C_local++; 97 lock(); 98 for (i = 0; i < __arraycount(C); i++) 99 C0[i] = C[i].v; 100 __insn_barrier(); 101 for (i = __arraycount(C); i --> 0;) 102 C[i].v = C0[i] + 1; 103 unlock(); 104 } 105 106 TC[me] = C_local; 107 108 return NULL; 109 } 110 111 ATF_TC(spinlock); 112 ATF_TC_HEAD(spinlock, tc) 113 { 114 atf_tc_set_md_var(tc, "descr", 115 "Verify membar_acquire/release work for spin locks"); 116 } 117 ATF_TC_BODY(spinlock, tc) 118 { 119 pthread_t t[2]; 120 unsigned i; 121 int ncpu; 122 size_t ncpulen = sizeof(ncpu); 123 int error; 124 125 alarm(10); 126 127 if (sysctlbyname("hw.ncpu", &ncpu, &ncpulen, NULL, 0) == -1) 128 atf_tc_fail("hw.ncpu: (%d) %s", errno, strerror(errno)); 129 assert(ncpulen == sizeof(ncpu)); 130 if (ncpu == 1) 131 atf_tc_skip("membar tests are only for multicore systems"); 132 133 for (i = 0; i < 2; i++) { 134 error = pthread_create(&t[i], NULL, &thread, 135 (void *)(uintptr_t)i); 136 if (error) 137 errc(1, error, "pthread_create"); 138 } 139 sleep(5); 140 times_up = 1; 141 for (i = 0; i < 2; i++) { 142 error = pthread_join(t[i], NULL); 143 if (error) 144 errc(1, error, "pthread_join"); 145 } 146 for (i = 0; i < __arraycount(C); i++) { 147 ATF_CHECK_MSG(C[i].v == TC[0] + TC[1], "%d: " 148 "%"PRIu64" != %"PRIu64" + %"PRIu64" (off by %"PRIdMAX")", 149 i, C[i].v, TC[0], TC[1], TC[0] + TC[1] - C[i].v); 150 } 151 } 152 153 ATF_TP_ADD_TCS(tp) 154 { 155 156 ATF_TP_ADD_TC(tp, spinlock); 157 return atf_no_error(); 158 } 159