1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright (c) 2020 Kyle Evans <kevans@FreeBSD.org> 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 26 */ 27 28 #include <sys/cdefs.h> 29 __FBSDID("$FreeBSD$"); 30 31 #include <sys/types.h> 32 #include <sys/umtx.h> 33 34 #include <pthread.h> 35 36 #include <atf-c.h> 37 38 /* 39 * This is an implementation detail of _umtx_op(2), pulled from 40 * sys/kern/kern_umtx.c. The relevant bug observed that requests above the 41 * batch side would not function as intended, so it's important that this 42 * reflects the BATCH_SIZE configured there. 43 */ 44 #define UMTX_OP_BATCH_SIZE 128 45 #define THREAD_COUNT ((UMTX_OP_BATCH_SIZE * 3) / 2) 46 47 static pthread_mutex_t static_mutex = PTHREAD_MUTEX_INITIALIZER; 48 49 static int batched_waiting; 50 51 static void * 52 batching_threadfunc(void *arg) 53 { 54 55 pthread_mutex_lock(&static_mutex); 56 ++batched_waiting; 57 pthread_mutex_unlock(&static_mutex); 58 _umtx_op(arg, UMTX_OP_WAIT_UINT_PRIVATE, 0, NULL, NULL); 59 60 return (NULL); 61 } 62 63 ATF_TC(batching); 64 ATF_TC_HEAD(batching, tc) 65 { 66 atf_tc_set_md_var(tc, "descr", 67 "Checks batching of UMTX_OP_NWAKE_PRIVATE"); 68 } 69 ATF_TC_BODY(batching, tc) 70 { 71 uintptr_t addrs[THREAD_COUNT]; 72 uint32_t vals[THREAD_COUNT]; 73 pthread_t threads[THREAD_COUNT]; 74 75 for (int i = 0; i < THREAD_COUNT; i++) { 76 addrs[i] = (uintptr_t)&vals[i]; 77 vals[i] = 0; 78 pthread_create(&threads[i], NULL, batching_threadfunc, 79 &vals[i]); 80 } 81 82 pthread_mutex_lock(&static_mutex); 83 while (batched_waiting != THREAD_COUNT) { 84 pthread_mutex_unlock(&static_mutex); 85 pthread_yield(); 86 pthread_mutex_lock(&static_mutex); 87 } 88 89 /* 90 * Spin for another .50 seconds to make sure they're all safely in the 91 * kernel. 92 */ 93 usleep(500000); 94 95 pthread_mutex_unlock(&static_mutex); 96 _umtx_op(addrs, UMTX_OP_NWAKE_PRIVATE, THREAD_COUNT, NULL, NULL); 97 98 for (int i = 0; i < THREAD_COUNT; i++) { 99 ATF_REQUIRE_EQ(0, pthread_join(threads[i], NULL)); 100 } 101 } 102 103 ATF_TP_ADD_TCS(tp) 104 { 105 106 ATF_TP_ADD_TC(tp, batching); 107 return (atf_no_error()); 108 } 109