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