--- a/src/hotspot/cpu/x86/sharedRuntime_x86_64.cpp	Tue Jul 31 16:49:51 2018 +0100
+++ b/src/hotspot/cpu/x86/sharedRuntime_x86_64.cpp	Tue Jul 31 13:12:06 2018 -0400
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2017, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -1434,6 +1434,64 @@
   }
 }
 
+// Pin object, return pinned object or null in rax
+static void gen_pin_object(MacroAssembler* masm,
+                           VMRegPair reg) {
+  __ block_comment("gen_pin_object {");
+
+  // rax always contains oop, either incoming or
+  // pinned.
+  Register tmp_reg = rax;
+
+  Label is_null;
+  VMRegPair tmp;
+  VMRegPair in_reg = reg;
+
+  tmp.set_ptr(tmp_reg->as_VMReg());
+  if (reg.first()->is_stack()) {
+    // Load the arg up from the stack
+    move_ptr(masm, reg, tmp);
+    reg = tmp;
+  } else {
+    __ movptr(rax, reg.first()->as_Register());
+  }
+  __ testptr(reg.first()->as_Register(), reg.first()->as_Register());
+  __ jccb(Assembler::equal, is_null);
+
+  if (reg.first()->as_Register() != c_rarg1) {
+    __ movptr(c_rarg1, reg.first()->as_Register());
+  }
+
+  __ call_VM_leaf(
+    CAST_FROM_FN_PTR(address, SharedRuntime::pin_object),
+    r15_thread, c_rarg1);
+
+  __ bind(is_null);
+  __ block_comment("} gen_pin_object");
+}
+
+// Unpin object
+static void gen_unpin_object(MacroAssembler* masm,
+                             VMRegPair reg) {
+  __ block_comment("gen_unpin_object {");
+  Label is_null;
+
+  if (reg.first()->is_stack()) {
+    __ movptr(c_rarg1, Address(rbp, reg2offset_in(reg.first())));
+  } else if (reg.first()->as_Register() != c_rarg1) {
+    __ movptr(c_rarg1, reg.first()->as_Register());
+  }
+
+  __ testptr(c_rarg1, c_rarg1);
+  __ jccb(Assembler::equal, is_null);
+
+  __ call_VM_leaf(
+    CAST_FROM_FN_PTR(address, SharedRuntime::unpin_object),
+    r15_thread, c_rarg1);
+
+  __ bind(is_null);
+  __ block_comment("} gen_unpin_object");
+}
 
 // Check GCLocker::needs_gc and enter the runtime if it's true.  This
 // keeps a new JNI critical region from starting until a GC has been
@@ -2129,7 +2187,7 @@
 
   const Register oop_handle_reg = r14;
 
-  if (is_critical_native) {
+  if (is_critical_native && !Universe::heap()->supports_object_pinning()) {
     check_needs_gc_for_critical_native(masm, stack_slots, total_c_args, total_in_args,
                                        oop_handle_offset, oop_maps, in_regs, in_sig_bt);
   }
@@ -2186,6 +2244,11 @@
   // the incoming and outgoing registers are offset upwards and for
   // critical natives they are offset down.
   GrowableArray<int> arg_order(2 * total_in_args);
+  // Inbound arguments that need to be pinned for critical natives
+  GrowableArray<int> pinned_args(total_in_args);
+  // Current stack slot for storing register based array argument
+  int pinned_slot = oop_handle_offset;
+
   VMRegPair tmp_vmreg;
   tmp_vmreg.set2(rbx->as_VMReg());
 
@@ -2233,6 +2296,23 @@
     switch (in_sig_bt[i]) {
       case T_ARRAY:
         if (is_critical_native) {
+          // pin before unpack
+          if (Universe::heap()->supports_object_pinning()) {
+            save_args(masm, total_c_args, 0, out_regs);
+            gen_pin_object(masm, in_regs[i]);
+            pinned_args.append(i);
+            restore_args(masm, total_c_args, 0, out_regs);
+
+            // rax has pinned array
+            VMRegPair result_reg;
+            result_reg.set_ptr(rax->as_VMReg());
+            move_ptr(masm, result_reg, in_regs[i]);
+            if (!in_regs[i].first()->is_stack()) {
+              assert(pinned_slot <= stack_slots, "overflow");
+              move_ptr(masm, result_reg, VMRegImpl::stack2reg(pinned_slot));
+              pinned_slot += VMRegImpl::slots_per_word;
+            }
+          }
           unpack_array_argument(masm, in_regs[i], in_elem_bt[i], out_regs[c_arg + 1], out_regs[c_arg]);
           c_arg++;
 #ifdef ASSERT
@@ -2449,6 +2529,24 @@
   default       : ShouldNotReachHere();
   }
 
+  // unpin pinned arguments
+  pinned_slot = oop_handle_offset;
+  if (pinned_args.length() > 0) {
+    // save return value that may be overwritten otherwise.
+    save_native_result(masm, ret_type, stack_slots);
+    for (int index = 0; index < pinned_args.length(); index ++) {
+      int i = pinned_args.at(index);
+      assert(pinned_slot <= stack_slots, "overflow");
+      if (!in_regs[i].first()->is_stack()) {
+        int offset = pinned_slot * VMRegImpl::stack_slot_size;
+        __ movq(in_regs[i].first()->as_Register(), Address(rsp, offset));
+        pinned_slot += VMRegImpl::slots_per_word;
+      }
+      gen_unpin_object(masm, in_regs[i]);
+    }
+    restore_native_result(masm, ret_type, stack_slots);
+  }
+
   // Switch thread to "native transition" state before reading the synchronization state.
   // This additional state is necessary because reading and testing the synchronization
   // state is not atomic w.r.t. GC, as this scenario demonstrates:

--- a/src/hotspot/share/runtime/sharedRuntime.cpp	Tue Jul 31 16:49:51 2018 +0100
+++ b/src/hotspot/share/runtime/sharedRuntime.cpp	Tue Jul 31 13:12:06 2018 -0400
@@ -2863,6 +2863,22 @@
   GCLocker::unlock_critical(thread);
 JRT_END
 
+JRT_LEAF(oopDesc*, SharedRuntime::pin_object(JavaThread* thread, oopDesc* obj))
+  assert(Universe::heap()->supports_object_pinning(), "Why we are here?");
+  assert(obj != NULL, "Should not be null");
+  oop o(obj);
+  o = Universe::heap()->pin_object(thread, o);
+  assert(o != NULL, "Should not be null");
+  return o;
+JRT_END
+
+JRT_LEAF(void, SharedRuntime::unpin_object(JavaThread* thread, oopDesc* obj))
+  assert(Universe::heap()->supports_object_pinning(), "Why we are here?");
+  assert(obj != NULL, "Should not be null");
+  oop o(obj);
+  Universe::heap()->unpin_object(thread, o);
+JRT_END
+
 // -------------------------------------------------------------------------
 // Java-Java calling convention
 // (what you use when Java calls Java)

--- a/src/hotspot/share/runtime/sharedRuntime.hpp	Tue Jul 31 16:49:51 2018 +0100
+++ b/src/hotspot/share/runtime/sharedRuntime.hpp	Tue Jul 31 13:12:06 2018 -0400
@@ -486,6 +486,10 @@
   // Block before entering a JNI critical method
   static void block_for_jni_critical(JavaThread* thread);
 
+  // Pin/Unpin object
+  static oopDesc* pin_object(JavaThread* thread, oopDesc* obj);
+  static void unpin_object(JavaThread* thread, oopDesc* obj);
+
   // A compiled caller has just called the interpreter, but compiled code
   // exists.  Patch the caller so he no longer calls into the interpreter.
   static void fixup_callers_callsite(Method* moop, address ret_pc);

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/hotspot/jtreg/gc/epsilon/CriticalNativeArgs.java	Tue Jul 31 13:12:06 2018 -0400
@@ -0,0 +1,52 @@
+/*
+ * Copyright (c) 2018, Red Hat, Inc. and/or its affiliates.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+
+/*
+ * @test CriticalNativeStress
+ * @key gc
+ * @bug 8199868
+ * @requires (os.arch =="x86_64" | os.arch == "amd64") & (vm.bits == "64") & vm.gc.Epsilon & !vm.graal.enabled
+ * @summary test argument unpacking nmethod wrapper of critical native method
+ * @run main/othervm/native -XX:+UnlockExperimentalVMOptions -XX:+UseEpsilonGC -Xcomp -Xmx256M -XX:+CriticalJNINatives CriticalNativeArgs
+ */
+public class CriticalNativeArgs {
+  static {
+    System.loadLibrary("CriticalNative");
+  }
+
+  static native boolean isNull(int[] a);
+
+  public static void main(String[] args) {
+    int[] arr = new int[2];
+
+    if (isNull(arr)) {
+      throw new RuntimeException("Should not be null");
+    }
+
+    if (!isNull(null)) {
+      throw new RuntimeException("Should be null");
+    }
+  }
+}
+

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/hotspot/jtreg/gc/epsilon/CriticalNativeStress.java	Tue Jul 31 13:12:06 2018 -0400
@@ -0,0 +1,197 @@
+/*
+ * Copyright (c) 2018, Red Hat, Inc. and/or its affiliates.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+import java.util.Random;
+
+/*
+ * @test CriticalNativeStress
+ * @key gc
+ * @bug 8199868
+ * @requires (os.arch =="x86_64" | os.arch == "amd64") & (vm.bits == "64") & vm.gc.Epsilon & !vm.graal.enabled
+ * @summary test argument pinning by nmethod wrapper of critical native method
+ * @run main/othervm/native -XX:+UnlockExperimentalVMOptions -XX:+UseEpsilonGC -Xcomp -Xmx1G -XX:+CriticalJNINatives CriticalNativeStress
+ */
+public class CriticalNativeStress {
+  private static Random rand = new Random();
+  static {
+    System.loadLibrary("CriticalNative");
+  }
+
+  // CYCLES and THREAD_PER_CASE are used to tune the tests for different GC settings,
+  // so that they can execrise enough GC cycles and not OOM
+  private static int CYCLES = Integer.getInteger("cycles", 3);
+  private static int THREAD_PER_CASE = Integer.getInteger("threadPerCase", 1);
+
+  static native long sum1(long[] a);
+
+  // More than 6 parameters
+  static native long sum2(long a1, int[] a2, int[] a3, long[] a4, int[] a5);
+
+  static long sum(long[] a) {
+    long sum = 0;
+    for (int index = 0; index < a.length; index ++) {
+      sum += a[index];
+    }
+    return sum;
+  }
+
+  static long sum(int[] a) {
+    long sum = 0;
+    for (int index = 0; index < a.length; index ++) {
+      sum += a[index];
+    }
+    return sum;
+  }
+
+  private static volatile String garbage_array[];
+
+  // GC potentially moves arrays passed to critical native methods
+  // if they are not pinned correctly.
+  // Create enough garbages to exercise GC cycles, verify
+  // the arrays are pinned correctly.
+  static void create_garbage(int len) {
+    len = Math.max(len, 1024);
+    String array[] = new String[len];
+    for (int index = 0; index < len; index ++) {
+      array[index] = "String " + index;
+    }
+    garbage_array = array;
+  }
+
+  // Two test cases with different method signatures:
+  // Tests generate arbitrary length of arrays with
+  // arbitrary values, then calcuate sum of the array
+  // elements with critical native JNI methods and java
+  // methods, and compare the results for correctness.
+  static void run_test_case1() {
+    // Create testing arary with arbitrary length and
+    // values
+    int length = rand.nextInt(50) + 1;
+    long[] arr = new long[length];
+    for (int index = 0; index < length; index ++) {
+      arr[index] = rand.nextLong() % 1002;
+    }
+
+    // Generate garbages to trigger GCs
+    for (int index = 0; index < length; index ++) {
+      create_garbage(index);
+    }
+
+    // Compare results for correctness.
+    long native_sum = sum1(arr);
+    long java_sum = sum(arr);
+    if (native_sum != java_sum) {
+      StringBuffer sb = new StringBuffer("Sums do not match: native = ")
+        .append(native_sum).append(" java = ").append(java_sum);
+
+      throw new RuntimeException(sb.toString());
+    }
+  }
+
+  static void run_test_case2() {
+    // Create testing arary with arbitrary length and
+    // values
+    int index;
+    long a1 = rand.nextLong() % 1025;
+
+    int a2_length = rand.nextInt(50) + 1;
+    int[] a2 = new int[a2_length];
+    for (index = 0; index < a2_length; index ++) {
+      a2[index] = rand.nextInt(106);
+    }
+
+    int a3_length = rand.nextInt(150) + 1;
+    int[] a3 = new int[a3_length];
+    for (index = 0; index < a3_length; index ++) {
+      a3[index] = rand.nextInt(3333);
+    }
+
+    int a4_length = rand.nextInt(200) + 1;
+    long[] a4 = new long[a4_length];
+    for (index = 0; index < a4_length; index ++) {
+      a4[index] = rand.nextLong() % 122;
+    }
+
+    int a5_length = rand.nextInt(350) + 1;
+    int[] a5 = new int[a5_length];
+    for (index = 0; index < a5_length; index ++) {
+      a5[index] = rand.nextInt(333);
+    }
+
+    // Generate garbages to trigger GCs
+    for (index = 0; index < a1; index ++) {
+      create_garbage(index);
+    }
+
+    // Compare results for correctness.
+    long native_sum = sum2(a1, a2, a3, a4, a5);
+    long java_sum = a1 + sum(a2) + sum(a3) + sum(a4) + sum(a5);
+    if (native_sum != java_sum) {
+      StringBuffer sb = new StringBuffer("Sums do not match: native = ")
+        .append(native_sum).append(" java = ").append(java_sum);
+
+      throw new RuntimeException(sb.toString());
+    }
+  }
+
+  static class Case1Runner extends Thread {
+    public Case1Runner() {
+      start();
+    }
+
+    public void run() {
+      for (int index = 0; index < CYCLES; index ++) {
+        run_test_case1();
+      }
+    }
+  }
+
+  static class Case2Runner extends Thread {
+    public Case2Runner() {
+      start();
+    }
+
+    public void run() {
+      for (int index = 0; index < CYCLES; index ++) {
+        run_test_case2();
+      }
+    }
+  }
+
+  public static void main(String[] args) {
+    Thread[] thrs = new Thread[THREAD_PER_CASE * 2];
+    for (int index = 0; index < thrs.length; index = index + 2) {
+      thrs[index] = new Case1Runner();
+      thrs[index + 1] = new Case2Runner();
+    }
+
+    for (int index = 0; index < thrs.length; index ++) {
+      try {
+        thrs[index].join();
+      } catch (Exception e) {
+        e.printStackTrace();
+      }
+    }
+  }
+}
+

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/hotspot/jtreg/gc/epsilon/libCriticalNative.c	Tue Jul 31 13:12:06 2018 -0400
@@ -0,0 +1,124 @@
+/*
+ * Copyright (c) 2018, Red Hat, Inc. and/or its affiliates.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#include "jni.h"
+
+JNIEXPORT jlong JNICALL JavaCritical_CriticalNativeStress_sum1
+  (jint length, jlong* a) {
+  jlong sum = 0;
+  jint index;
+  for (index = 0; index < length; index ++) {
+    sum += a[index];
+  }
+
+  return sum;
+}
+
+JNIEXPORT jlong JNICALL  JavaCritical_CriticalNativeStress_sum2
+  (jlong a1, jint a2_length, jint* a2, jint a4_length, jint* a4, jint a6_length, jlong* a6, jint a8_length, jint* a8) {
+  jlong sum = a1;
+  jint index;
+  for (index = 0; index < a2_length; index ++) {
+    sum += a2[index];
+  }
+
+  for (index = 0; index < a4_length; index ++) {
+    sum += a4[index];
+  }
+
+  for (index = 0; index < a6_length; index ++) {
+    sum += a6[index];
+  }
+
+  for (index = 0; index < a8_length; index ++) {
+    sum += a8[index];
+  }
+  return sum;
+}
+
+JNIEXPORT jlong JNICALL Java_CriticalNativeStress_sum1
+  (JNIEnv *env, jclass jclazz, jlongArray a) {
+  jlong sum = 0;
+  jsize len = (*env)->GetArrayLength(env, a);
+  jsize index;
+  jlong* arr = (jlong*)(*env)->GetPrimitiveArrayCritical(env, a, 0);
+  for (index = 0; index < len; index ++) {
+    sum += arr[index];
+  }
+
+  (*env)->ReleasePrimitiveArrayCritical(env, a, arr, 0);
+  return sum;
+}
+
+JNIEXPORT jlong JNICALL Java_CriticalNativeStress_sum2
+  (JNIEnv *env, jclass jclazz, jlong a1, jintArray a2, jintArray a3, jlongArray a4, jintArray a5) {
+  jlong sum = a1;
+  jsize index;
+  jsize len = (*env)->GetArrayLength(env, a2);
+  jint* a2_arr = (jint*)(*env)->GetPrimitiveArrayCritical(env, a2, 0);
+  for (index = 0; index < len; index ++) {
+    sum += a2_arr[index];
+  }
+  (*env)->ReleasePrimitiveArrayCritical(env, a2, a2_arr, 0);
+
+  len = (*env)->GetArrayLength(env, a3);
+  jint* a3_arr = (jint*)(*env)->GetPrimitiveArrayCritical(env, a3, 0);
+  for (index = 0; index < len; index ++) {
+    sum += a3_arr[index];
+  }
+  (*env)->ReleasePrimitiveArrayCritical(env, a3, a3_arr, 0);
+
+
+  len = (*env)->GetArrayLength(env, a4);
+  jlong* a4_arr = (jlong*)(*env)->GetPrimitiveArrayCritical(env, a4, 0);
+  for (index = 0; index < len; index ++) {
+    sum += a4_arr[index];
+  }
+  (*env)->ReleasePrimitiveArrayCritical(env, a4, a4_arr, 0);
+
+  len = (*env)->GetArrayLength(env, a5);
+  jint* a5_arr = (jint*)(*env)->GetPrimitiveArrayCritical(env, a5, 0);
+  for (index = 0; index < len; index ++) {
+    sum += a5_arr[index];
+  }
+  (*env)->ReleasePrimitiveArrayCritical(env, a5, a5_arr, 0);
+
+  return sum;
+}
+
+
+JNIEXPORT jboolean JNICALL JavaCritical_CriticalNativeArgs_isNull
+  (jint length, jint* a) {
+  return (a == NULL) && (length == 0);
+}
+
+JNIEXPORT jboolean JNICALL Java_CriticalNativeArgs_isNull
+  (JNIEnv *env, jclass jclazz, jintArray a) {
+  jboolean is_null;
+  jsize len = (*env)->GetArrayLength(env, a);
+  jint* arr = (jint*)(*env)->GetPrimitiveArrayCritical(env, a, 0);
+  is_null = (arr == NULL) && (len == 0);
+  (*env)->ReleasePrimitiveArrayCritical(env, a, arr, 0);
+  return is_null;
+}
+