From 763fee1544c5e5f7dffcee678c98804f80c67249 Mon Sep 17 00:00:00 2001
From: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Date: Sat, 1 Feb 2020 23:38:11 +0100
Subject: [PATCH] Check for sys/auxv.h

Check for sys/auxv.h and getauxval before using them as they are not
always available (for example on uclibc)

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
[Upstream status: https://github.com/facebook/rocksdb/pull/6359]
---
 CMakeLists.txt       | 5 +++++
 util/crc32c.cc       | 4 +++-
 util/crc32c_arm64.cc | 6 ++++++
 3 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 017fe8675..32fc5cb30 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -481,6 +481,11 @@ if(HAVE_SCHED_GETCPU)
   add_definitions(-DROCKSDB_SCHED_GETCPU_PRESENT)
 endif()
 
+check_cxx_symbol_exists(getauxval auvx.h HAVE_AUXV_GETAUXVAL)
+if(HAVE_AUXV_GETAUXVAL)
+  add_definitions(-DROCKSDB_AUXV_GETAUXVAL_PRESENT)
+endif()
+
 include_directories(${PROJECT_SOURCE_DIR})
 include_directories(${PROJECT_SOURCE_DIR}/include)
 include_directories(SYSTEM ${PROJECT_SOURCE_DIR}/third-party/gtest-1.8.1/fused-src)
diff --git a/util/crc32c.cc b/util/crc32c.cc
index 9e838b830..3063884db 100644
--- a/util/crc32c.cc
+++ b/util/crc32c.cc
@@ -25,7 +25,9 @@
 #include "util/crc32c_ppc_constants.h"
 
 #if __linux__
+#ifdef ROCKSDB_AUXV_GETAUXVAL_PRESENT
 #include <sys/auxv.h>
+#endif
 
 #ifndef PPC_FEATURE2_VEC_CRYPTO
 #define PPC_FEATURE2_VEC_CRYPTO 0x02000000
@@ -451,7 +453,7 @@ uint32_t ExtendPPCImpl(uint32_t crc, const char *buf, size_t size) {
 static int arch_ppc_probe(void) {
   arch_ppc_crc32 = 0;
 
-#if defined(__powerpc64__)
+#if defined(__powerpc64__) && defined(ROCKSDB_AUXV_GETAUXVAL_PRESENT)
   if (getauxval(AT_HWCAP2) & PPC_FEATURE2_VEC_CRYPTO) arch_ppc_crc32 = 1;
 #endif /* __powerpc64__ */
 
diff --git a/util/crc32c_arm64.cc b/util/crc32c_arm64.cc
index 591c623a5..61b2ccaba 100644
--- a/util/crc32c_arm64.cc
+++ b/util/crc32c_arm64.cc
@@ -8,7 +8,9 @@
 #if defined(__linux__) && defined(HAVE_ARM64_CRC)
 
 #include <asm/hwcap.h>
+#ifdef ROCKSDB_AUXV_GETAUXVAL_PRESENT
 #include <sys/auxv.h>
+#endif
 #ifndef HWCAP_CRC32
 #define HWCAP_CRC32 (1 << 7)
 #endif
@@ -34,8 +36,12 @@
 #endif
 
 uint32_t crc32c_runtime_check(void) {
+#ifdef ROCKSDB_AUXV_GETAUXVAL_PRESENT
   uint64_t auxv = getauxval(AT_HWCAP);
   return (auxv & HWCAP_CRC32) != 0;
+#else
+  return 0;
+#endif
 }
 
 uint32_t crc32c_arm64(uint32_t crc, unsigned char const *data,
-- 
2.24.1