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/types.h> 29 #include <sys/umtx.h> 30 31 #include <pthread.h> 32 33 #include <atf-c.h> 34 35 /* 36 * This is an implementation detail of _umtx_op(2), pulled from 37 * sys/kern/kern_umtx.c. The relevant bug observed that requests above the 38 * batch side would not function as intended, so it's important that this 39 * reflects the BATCH_SIZE configured there. 40 */ 41 #define UMTX_OP_BATCH_SIZE 128 42 #define THREAD_COUNT ((UMTX_OP_BATCH_SIZE * 3) / 2) 43 44 static pthread_mutex_t static_mutex = PTHREAD_MUTEX_INITIALIZER; 45 46 static int batched_waiting; 47 48 static void * 49 batching_threadfunc(void *arg) 50 { 51 52 pthread_mutex_lock(&static_mutex); 53 ++batched_waiting; 54 pthread_mutex_unlock(&static_mutex); 55 _umtx_op(arg, UMTX_OP_WAIT_UINT_PRIVATE, 0, NULL, NULL); 56 57 return (NULL); 58 } 59 60 ATF_TC(batching); 61 ATF_TC_HEAD(batching, tc) 62 { 63 atf_tc_set_md_var(tc, "descr", 64 "Checks batching of UMTX_OP_NWAKE_PRIVATE"); 65 } 66 ATF_TC_BODY(batching, tc) 67 { 68 uintptr_t addrs[THREAD_COUNT]; 69 uint32_t vals[THREAD_COUNT]; 70 pthread_t threads[THREAD_COUNT]; 71 72 for (int i = 0; i < THREAD_COUNT; i++) { 73 addrs[i] = (uintptr_t)&vals[i]; 74 vals[i] = 0; 75 pthread_create(&threads[i], NULL, batching_threadfunc, 76 &vals[i]); 77 } 78 79 pthread_mutex_lock(&static_mutex); 80 while (batched_waiting != THREAD_COUNT) { 81 pthread_mutex_unlock(&static_mutex); 82 pthread_yield(); 83 pthread_mutex_lock(&static_mutex); 84 } 85 86 /* 87 * Spin for another .50 seconds to make sure they're all safely in the 88 * kernel. 89 */ 90 usleep(500000); 91 92 pthread_mutex_unlock(&static_mutex); 93 _umtx_op(addrs, UMTX_OP_NWAKE_PRIVATE, THREAD_COUNT, NULL, NULL); 94 95 for (int i = 0; i < THREAD_COUNT; i++) { 96 ATF_REQUIRE_EQ(0, pthread_join(threads[i], NULL)); 97 } 98 } 99 100 ATF_TP_ADD_TCS(tp) 101 { 102 103 ATF_TP_ADD_TC(tp, batching); 104 return (atf_no_error()); 105 } 106