xref: /xnu-8792.61.2/tests/x18_entitled.c (revision 42e220869062b56f8d7d0726fd4c88954f87902c)
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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("joster"),
39 	T_META_REQUIRES_SYSCTL_EQ("hw.optional.arm_kernel_protect", 0), // entitlement will crash on arm_kernel_protect devices
40 	T_META_RUN_CONCURRENTLY(true));
41 
42 T_DECL(x18_entitled,
43     "Test that x18 is preserved on hardware that supports it, if entitled.")
44 {
45 #ifndef __arm64__
46 	T_SKIP("Running on non-arm64 target, skipping...");
47 #else
48 	uint64_t x18_val;
49 	for (uint64_t i = 0xFEEDB0B000000000ULL; i < 0xFEEDB0B000000000ULL + 10000; ++i) {
50 		asm volatile ("mov x18, %0" : : "r"(i));
51 		sched_yield();
52 		asm volatile ("mov %0, x18" : "=r"(x18_val));
53 		T_QUIET; T_ASSERT_EQ(x18_val, i, "check that x18 reads back correctly after yield");
54 	}
55 #endif
56 }
57