/* * Copyright (c) 2019 Apple Computer, Inc. All rights reserved. * * @APPLE_OSREFERENCE_LICENSE_HEADER_START@ * * This file contains Original Code and/or Modifications of Original Code * as defined in and that are subject to the Apple Public Source License * Version 2.0 (the 'License'). You may not use this file except in * compliance with the License. The rights granted to you under the License * may not be used to create, or enable the creation or redistribution of, * unlawful or unlicensed copies of an Apple operating system, or to * circumvent, violate, or enable the circumvention or violation of, any * terms of an Apple operating system software license agreement. * * Please obtain a copy of the License at * http://www.opensource.apple.com/apsl/ and read it before using this file. * * The Original Code and all software distributed under the License are * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. * Please see the License for the specific language governing rights and * limitations under the License. * * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ */ #include <darwintest.h> #include <pthread.h> #include <sys/types.h> #include <sys/sysctl.h> T_GLOBAL_META( T_META_NAMESPACE("xnu.arm"), T_META_RUN_CONCURRENTLY(true)); T_DECL(x18_preserved, "Test that x18 is preserved on hardware that supports it.") { #ifndef __arm64__ T_SKIP("Running on non-arm64 target, skipping..."); #else int arm_kernel_protect = 0; size_t arm_kernel_protect_size = sizeof(arm_kernel_protect); bool preserved = true; int err = sysctlbyname("hw.optional.arm_kernel_protect", &arm_kernel_protect, &arm_kernel_protect_size, NULL, 0); if (err) { T_SKIP("Could not determine state of __ARM_KERNEL_PROTECT__, skipping..."); } if (arm_kernel_protect) { preserved = false; } uint64_t x18_val; for (uint64_t i = 0xFEEDB0B000000000ULL; i < 0xFEEDB0B000000000ULL + 10000; ++i) { asm volatile ("mov x18, %0" : : "r"(i)); sched_yield(); asm volatile ("mov %0, x18" : "=r"(x18_val)); if (preserved) { T_QUIET; T_ASSERT_EQ(x18_val, i, "check that x18 reads back correctly after yield"); } else { T_QUIET; T_ASSERT_EQ(x18_val, 0ULL, "check that x18 is cleared after yield"); } } #endif }