s390: use /proc/cpuinfo to check vx availability

R=joransiu@ca.ibm.com, bjaideep@ca.ibm.com

Bug: 
Change-Id: I73c44a0dd93e3925dbe895a477175d255edbed56
Reviewed-on: https://chromium-review.googlesource.com/514123Reviewed-by: Joran Siu <joransiu@ca.ibm.com>
Commit-Queue: Junliang Yan <jyan@ca.ibm.com>
Cr-Commit-Position: refs/heads/master@{#45532}

src/s390/assembler-s390.cc

@@ -35,6 +35,9 @@
 // Copyright 2014 the V8 project authors. All rights reserved.
 
 #include "src/s390/assembler-s390.h"
+#include <sys/auxv.h>
+#include <set>
+#include <string>
 
 #if V8_TARGET_ARCH_S390
 
@@ -57,6 +60,43 @@ static unsigned CpuFeaturesImpliedByCompiler() {
   return answer;
 }
 
+static bool supportsCPUFeature(const char* feature) {
+  static std::set<std::string> features;
+  static std::set<std::string> all_available_features = {
+      "iesan3", "zarch",  "stfle",    "msa", "ldisp", "eimm",
+      "dfp",    "etf3eh", "highgprs", "te",  "vx"};
+  if (features.empty()) {
+#if V8_HOST_ARCH_S390
+
+#ifndef HWCAP_S390_VX
+#define HWCAP_S390_VX 2048
+#endif
+#define CHECK_AVAILABILITY_FOR(mask, value) \
+  if (f & mask) features.insert(value);
+
+    // initialize feature vector
+    uint64_t f = getauxval(AT_HWCAP);
+    CHECK_AVAILABILITY_FOR(HWCAP_S390_ESAN3, "iesan3")
+    CHECK_AVAILABILITY_FOR(HWCAP_S390_ZARCH, "zarch")
+    CHECK_AVAILABILITY_FOR(HWCAP_S390_STFLE, "stfle")
+    CHECK_AVAILABILITY_FOR(HWCAP_S390_MSA, "msa")
+    CHECK_AVAILABILITY_FOR(HWCAP_S390_LDISP, "ldisp")
+    CHECK_AVAILABILITY_FOR(HWCAP_S390_EIMM, "eimm")
+    CHECK_AVAILABILITY_FOR(HWCAP_S390_DFP, "dfp")
+    CHECK_AVAILABILITY_FOR(HWCAP_S390_ETF3EH, "etf3eh")
+    CHECK_AVAILABILITY_FOR(HWCAP_S390_HIGH_GPRS, "highgprs")
+    CHECK_AVAILABILITY_FOR(HWCAP_S390_TE, "te")
+    CHECK_AVAILABILITY_FOR(HWCAP_S390_VX, "vx")
+#else
+    // import all features
+    features.insert(all_available_features.begin(),
+                    all_available_features.end());
+#endif
+  }
+  USE(all_available_features);
+  return features.find(feature) != features.end();
+}
+
 // Check whether Store Facility STFLE instruction is available on the platform.
 // Instruction returns a bit vector of the enabled hardware facilities.
 static bool supportsSTFLE() {
@@ -106,8 +146,8 @@ static bool supportsSTFLE() {
 
   // HWCAP_S390_STFLE is defined to be 4 in include/asm/elf.h.  Currently
   // hardcoded in case that include file does not exist.
-  const uint32_t HWCAP_S390_STFLE = 4;
-  return (auxv_hwcap & HWCAP_S390_STFLE);
+  const uint32_t _HWCAP_S390_STFLE = 4;
+  return (auxv_hwcap & _HWCAP_S390_STFLE);
 #else
   // STFLE is not available on non-s390 hosts
   return false;
@@ -163,7 +203,8 @@ void CpuFeatures::ProbeImpl(bool cross_compile) {
       supported_ |= (1u << FLOATING_POINT_EXT);
     }
     // Test for Vector Facility - Bit 129
-    if (facilities[2] & (one << (63 - (129 - 128)))) {
+    if (facilities[2] & (one << (63 - (129 - 128))) &&
+        supportsCPUFeature("vx")) {
       supported_ |= (1u << VECTOR_FACILITY);
     }
     // Test for Miscellaneous Instruction Extension Facility - Bit 58
@@ -179,6 +220,7 @@ void CpuFeatures::ProbeImpl(bool cross_compile) {
   supported_ |= (1u << FLOATING_POINT_EXT);
   supported_ |= (1u << MISC_INSTR_EXT2);
   USE(performSTFLE);  // To avoid assert
+  USE(supportsCPUFeature);
   supported_ |= (1u << VECTOR_FACILITY);
 #endif
   supported_ |= (1u << FPU);