1*cb14a3feSDimitry Andric#include <string.h> 2*cb14a3feSDimitry Andric#include <sys/auxv.h> 3*cb14a3feSDimitry Andric#include <sys/system_properties.h> 4*cb14a3feSDimitry Andric 5*cb14a3feSDimitry Andricstatic bool __isExynos9810(void) { 6*cb14a3feSDimitry Andric char arch[PROP_VALUE_MAX]; 7*cb14a3feSDimitry Andric return __system_property_get("ro.arch", arch) > 0 && 8*cb14a3feSDimitry Andric strncmp(arch, "exynos9810", sizeof("exynos9810") - 1) == 0; 9*cb14a3feSDimitry Andric} 10*cb14a3feSDimitry Andric 11*cb14a3feSDimitry Andricstatic void CONSTRUCTOR_ATTRIBUTE init_have_lse_atomics(void) { 12*cb14a3feSDimitry Andric unsigned long hwcap = getauxval(AT_HWCAP); 13*cb14a3feSDimitry Andric _Bool result = (hwcap & HWCAP_ATOMICS) != 0; 14*cb14a3feSDimitry Andric if (result) { 15*cb14a3feSDimitry Andric // Some cores in the Exynos 9810 CPU are ARMv8.2 and others are ARMv8.0; 16*cb14a3feSDimitry Andric // only the former support LSE atomics. However, the kernel in the 17*cb14a3feSDimitry Andric // initial Android 8.0 release of Galaxy S9/S9+ devices incorrectly 18*cb14a3feSDimitry Andric // reported the feature as being supported. 19*cb14a3feSDimitry Andric // 20*cb14a3feSDimitry Andric // The kernel appears to have been corrected to mark it unsupported as of 21*cb14a3feSDimitry Andric // the Android 9.0 release on those devices, and this issue has not been 22*cb14a3feSDimitry Andric // observed anywhere else. Thus, this workaround may be removed if 23*cb14a3feSDimitry Andric // compiler-rt ever drops support for Android 8.0. 24*cb14a3feSDimitry Andric if (__isExynos9810()) 25*cb14a3feSDimitry Andric result = false; 26*cb14a3feSDimitry Andric } 27*cb14a3feSDimitry Andric __aarch64_have_lse_atomics = result; 28*cb14a3feSDimitry Andric} 29