1 /*
   2  * Copyright (c) 1999, 2010, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "code/codeCache.hpp"
  27 #include "code/nmethod.hpp"
  28 #include "runtime/frame.hpp"
  29 #include "runtime/init.hpp"
  30 #include "runtime/os.hpp"
  31 #include "utilities/debug.hpp"
  32 #include "utilities/top.hpp"
  33 
  34 void pd_ps(frame f) {}
  35 
  36 #ifndef PRODUCT
  37 // return an instruction which will generate a SIGILL
  38 bool get_illegal_instruction_sequence(uint8_t buf[8]) {
  39   const uint8_t sequence[] = {
  40 #if defined(AMD64)
  41     // 06 => invalid instruction for x64
  42     0x06
  43 #else
  44     // Note: privileged instructions won't work, because they cause a SIGSEGV 
  45     // on Linux, not a SIGILL. "0f 0e" and "0f 0f" are invalid opcodes which 
  46     // will cause real SIGILL resp. EXCEPTION_ILLEGAL_INSTRUCTION.
  47     0x0f, 0x0f,
  48     // in case this does not work, use a HLT which should be privilegued.
  49     0xF4
  50 #endif
  51   };
  52   memcpy(buf, sequence, sizeof(sequence));
  53   return true;
  54 }
  55 #endif
  56