add ROCKSDB_AUXV_GETAUXVAL_PRESENT for supported Linux systems

This lets RocksDB know that getauxval is supported which is needed to enable hardware accelerated crc32c for ARM on Linux

Author: zaidoon1

librocksdb-sys/Cargo.toml

@@ -51,7 +51,10 @@ tikv-jemalloc-sys = { version = "0.6", features = [
     "unprefixed_malloc_on_supported_platforms",
 ], optional = true }
 lz4-sys = { version = "1.10", optional = true }
-zstd-sys = { version = "2.0", features = ["zdict_builder", "experimental"], optional = true }
+zstd-sys = { version = "2.0", features = [
+    "zdict_builder",
+    "experimental",
+], optional = true }
 libz-sys = { version = "1.1", default-features = false, optional = true }
 bzip2-sys = { version = "0.1", default-features = false, optional = true }
 
@@ -64,3 +67,4 @@ cc = { version = "1.0", features = ["parallel"] }
 bindgen = { version = "0.69", default-features = false }
 glob = "0.3"
 pkg-config = { version = "0.3", optional = true }
+libc = "0.2"

librocksdb-sys/build.rs

@@ -1,6 +1,9 @@
 use std::path::Path;
 use std::{env, fs, path::PathBuf, process::Command};
 
+#[cfg(target_os = "linux")]
+use libc::{getauxval, AT_HWCAP};
+
 // On these platforms jemalloc-sys will use a prefixed jemalloc which cannot be linked together
 // with RocksDB.
 // See https://github.com/tikv/jemallocator/blob/f7adfca5aff272b43fd3ad896252b57fbbd9c72a/jemalloc-sys/src/env.rs#L24
@@ -50,6 +53,18 @@ fn bindgen_rocksdb() {
         .expect("unable to write rocksdb bindings");
 }
 
+#[cfg(target_os = "linux")]
+fn check_getauxval_supported() -> bool {
+    unsafe {
+        let aux_value = getauxval(AT_HWCAP);
+        if aux_value == 0 {
+            return false;
+        }
+
+        true
+    }
+}
+
 fn build_rocksdb() {
     let target = env::var("TARGET").unwrap();
 
@@ -192,6 +207,11 @@ fn build_rocksdb() {
         config.define("ROCKSDB_PLATFORM_POSIX", None);
         config.define("ROCKSDB_LIB_IO_POSIX", None);
         config.define("ROCKSDB_SCHED_GETCPU_PRESENT", None);
+
+        #[cfg(target_os = "linux")]
+        if check_getauxval_supported() {
+            config.define("ROCKSDB_AUXV_GETAUXVAL_PRESENT", None);
+        }
     } else if target.contains("dragonfly") {
         config.define("OS_DRAGONFLYBSD", None);
         config.define("ROCKSDB_PLATFORM_POSIX", None);