1*043036a2SApple OSS Distributions /* 2*043036a2SApple OSS Distributions * Copyright (c) 2019-2022 Apple Inc. All rights reserved. 3*043036a2SApple OSS Distributions * 4*043036a2SApple OSS Distributions * @APPLE_OSREFERENCE_LICENSE_HEADER_START@ 5*043036a2SApple OSS Distributions * 6*043036a2SApple OSS Distributions * This file contains Original Code and/or Modifications of Original Code 7*043036a2SApple OSS Distributions * as defined in and that are subject to the Apple Public Source License 8*043036a2SApple OSS Distributions * Version 2.0 (the 'License'). You may not use this file except in 9*043036a2SApple OSS Distributions * compliance with the License. The rights granted to you under the License 10*043036a2SApple OSS Distributions * may not be used to create, or enable the creation or redistribution of, 11*043036a2SApple OSS Distributions * unlawful or unlicensed copies of an Apple operating system, or to 12*043036a2SApple OSS Distributions * circumvent, violate, or enable the circumvention or violation of, any 13*043036a2SApple OSS Distributions * terms of an Apple operating system software license agreement. 14*043036a2SApple OSS Distributions * 15*043036a2SApple OSS Distributions * Please obtain a copy of the License at 16*043036a2SApple OSS Distributions * http://www.opensource.apple.com/apsl/ and read it before using this file. 17*043036a2SApple OSS Distributions * 18*043036a2SApple OSS Distributions * The Original Code and all software distributed under the License are 19*043036a2SApple OSS Distributions * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER 20*043036a2SApple OSS Distributions * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, 21*043036a2SApple OSS Distributions * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, 22*043036a2SApple OSS Distributions * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. 23*043036a2SApple OSS Distributions * Please see the License for the specific language governing rights and 24*043036a2SApple OSS Distributions * limitations under the License. 25*043036a2SApple OSS Distributions * 26*043036a2SApple OSS Distributions * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ 27*043036a2SApple OSS Distributions */ 28*043036a2SApple OSS Distributions 29*043036a2SApple OSS Distributions #include "context_helpers.h" 30*043036a2SApple OSS Distributions #include <darwintest.h> 31*043036a2SApple OSS Distributions #include <sys/types.h> 32*043036a2SApple OSS Distributions #include <sys/sysctl.h> 33*043036a2SApple OSS Distributions #include <stdbool.h> 34*043036a2SApple OSS Distributions #include <unistd.h> 35*043036a2SApple OSS Distributions 36*043036a2SApple OSS Distributions T_GLOBAL_META( 37*043036a2SApple OSS Distributions T_META_NAMESPACE("xnu.arm"), 38*043036a2SApple OSS Distributions T_META_RADAR_COMPONENT_NAME("xnu"), 39*043036a2SApple OSS Distributions T_META_RADAR_COMPONENT_VERSION("arm"), 40*043036a2SApple OSS Distributions T_META_OWNER("joster"), 41*043036a2SApple OSS Distributions T_META_REQUIRES_SYSCTL_EQ("hw.optional.arm_kernel_protect", 0), // entitlement will crash on arm_kernel_protect devices 42*043036a2SApple OSS Distributions T_META_RUN_CONCURRENTLY(true), 43*043036a2SApple OSS Distributions T_META_TAG_VM_PREFERRED); 44*043036a2SApple OSS Distributions 45*043036a2SApple OSS Distributions T_DECL(x18_entitled, 46*043036a2SApple OSS Distributions "Test that x18 is preserved on hardware that supports it, if entitled.") 47*043036a2SApple OSS Distributions { 48*043036a2SApple OSS Distributions #ifndef __arm64__ 49*043036a2SApple OSS Distributions T_SKIP("Running on non-arm64 target, skipping..."); 50*043036a2SApple OSS Distributions #else 51*043036a2SApple OSS Distributions bool did_csw = false; 52*043036a2SApple OSS Distributions uint64_t x18_val; 53*043036a2SApple OSS Distributions 54*043036a2SApple OSS Distributions for (uint64_t i = 0xFEEDB0B000000000ULL; i < 0xFEEDB0B000000000ULL + 10000; ++i) { 55*043036a2SApple OSS Distributions asm volatile ("mov x18, %0" : : "r"(i)); 56*043036a2SApple OSS Distributions int32_t const nr_csw = get_csw_count(); 57*043036a2SApple OSS Distributions int const rc = usleep(10); 58*043036a2SApple OSS Distributions int32_t const nr_csw_after = get_csw_count(); 59*043036a2SApple OSS Distributions 60*043036a2SApple OSS Distributions // There isn't any guarantee usleep() will actually context switch so this is a best effort way 61*043036a2SApple OSS Distributions // to see if we've switched at least once in all these iterations. 62*043036a2SApple OSS Distributions did_csw = did_csw || (nr_csw_after > nr_csw); 63*043036a2SApple OSS Distributions T_QUIET; T_ASSERT_EQ(0, rc, "usleep"); 64*043036a2SApple OSS Distributions asm volatile ("mov %0, x18" : "=r"(x18_val)); 65*043036a2SApple OSS Distributions T_QUIET; T_ASSERT_EQ(x18_val, i, "check that x18 reads back correctly after yield"); 66*043036a2SApple OSS Distributions } 67*043036a2SApple OSS Distributions 68*043036a2SApple OSS Distributions T_QUIET; T_ASSERT_TRUE(did_csw, "did not context switch, but should have."); 69*043036a2SApple OSS Distributions #endif 70*043036a2SApple OSS Distributions } 71