diff options
Diffstat (limited to 'contrib/llvm-project/compiler-rt/lib/builtins/cpu_model/aarch64/lse_atomics/android.inc')
-rw-r--r-- | contrib/llvm-project/compiler-rt/lib/builtins/cpu_model/aarch64/lse_atomics/android.inc | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/contrib/llvm-project/compiler-rt/lib/builtins/cpu_model/aarch64/lse_atomics/android.inc b/contrib/llvm-project/compiler-rt/lib/builtins/cpu_model/aarch64/lse_atomics/android.inc new file mode 100644 index 000000000000..94bf64a5b0b0 --- /dev/null +++ b/contrib/llvm-project/compiler-rt/lib/builtins/cpu_model/aarch64/lse_atomics/android.inc @@ -0,0 +1,28 @@ +#include <string.h> +#include <sys/auxv.h> +#include <sys/system_properties.h> + +static bool __isExynos9810(void) { + char arch[PROP_VALUE_MAX]; + return __system_property_get("ro.arch", arch) > 0 && + strncmp(arch, "exynos9810", sizeof("exynos9810") - 1) == 0; +} + +static void CONSTRUCTOR_ATTRIBUTE init_have_lse_atomics(void) { + unsigned long hwcap = getauxval(AT_HWCAP); + _Bool result = (hwcap & HWCAP_ATOMICS) != 0; + if (result) { + // Some cores in the Exynos 9810 CPU are ARMv8.2 and others are ARMv8.0; + // only the former support LSE atomics. However, the kernel in the + // initial Android 8.0 release of Galaxy S9/S9+ devices incorrectly + // reported the feature as being supported. + // + // The kernel appears to have been corrected to mark it unsupported as of + // the Android 9.0 release on those devices, and this issue has not been + // observed anywhere else. Thus, this workaround may be removed if + // compiler-rt ever drops support for Android 8.0. + if (__isExynos9810()) + result = false; + } + __aarch64_have_lse_atomics = result; +} |