1 /* 2 * Copyright (c) 2019 Apple Computer, Inc. All rights reserved. 3 * 4 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@ 5 * 6 * This file contains Original Code and/or Modifications of Original Code 7 * as defined in and that are subject to the Apple Public Source License 8 * Version 2.0 (the 'License'). You may not use this file except in 9 * compliance with the License. The rights granted to you under the License 10 * may not be used to create, or enable the creation or redistribution of, 11 * unlawful or unlicensed copies of an Apple operating system, or to 12 * circumvent, violate, or enable the circumvention or violation of, any 13 * terms of an Apple operating system software license agreement. 14 * 15 * Please obtain a copy of the License at 16 * http://www.opensource.apple.com/apsl/ and read it before using this file. 17 * 18 * The Original Code and all software distributed under the License are 19 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER 20 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, 21 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, 22 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. 23 * Please see the License for the specific language governing rights and 24 * limitations under the License. 25 * 26 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ 27 */ 28 29 #include <darwintest.h> 30 #include <pthread.h> 31 #include <sys/types.h> 32 #include <sys/sysctl.h> 33 34 T_GLOBAL_META( 35 T_META_NAMESPACE("xnu.arm"), 36 T_META_RADAR_COMPONENT_NAME("xnu"), 37 T_META_RADAR_COMPONENT_VERSION("arm"), 38 T_META_OWNER("jharmening"), 39 T_META_RUN_CONCURRENTLY(true)); 40 41 T_DECL(x18_preserved, 42 "Test that x18 is preserved on hardware that supports it.") 43 { 44 #ifndef __arm64__ 45 T_SKIP("Running on non-arm64 target, skipping..."); 46 #else 47 int arm_kernel_protect = 0; 48 size_t arm_kernel_protect_size = sizeof(arm_kernel_protect); 49 bool preserved = true; 50 51 int err = sysctlbyname("hw.optional.arm_kernel_protect", &arm_kernel_protect, &arm_kernel_protect_size, NULL, 0); 52 if (err) { 53 T_SKIP("Could not determine state of __ARM_KERNEL_PROTECT__, skipping..."); 54 } 55 if (arm_kernel_protect) { 56 preserved = false; 57 } 58 59 uint64_t x18_val; 60 for (uint64_t i = 0xFEEDB0B000000000ULL; i < 0xFEEDB0B000000000ULL + 10000; ++i) { 61 asm volatile ("mov x18, %0" : : "r"(i)); 62 sched_yield(); 63 asm volatile ("mov %0, x18" : "=r"(x18_val)); 64 if (preserved) { 65 T_QUIET; T_ASSERT_EQ(x18_val, i, "check that x18 reads back correctly after yield"); 66 } else { 67 T_QUIET; T_ASSERT_EQ(x18_val, 0ULL, "check that x18 is cleared after yield"); 68 } 69 } 70 #endif 71 } 72