view src/os_cpu/linux_x86/vm/os_linux_x86.hpp @ 5204:9790755de9a6

8023956: Provide a work-around to broken Linux 32 bit "Exec Shield" using CS for NX emulation (crashing with SI_KERNEL) Summary: Execute some code at a high virtual address value, and keep mapped Reviewed-by: coleenp, zgu
author dsimms
date Wed, 25 Sep 2013 13:58:13 +0200
parents 7ab5f6318694
children
line wrap: on
line source
/*
 * Copyright (c) 1999, 2011, 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
 * 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.
 *
 */

#ifndef OS_CPU_LINUX_X86_VM_OS_LINUX_X86_HPP
#define OS_CPU_LINUX_X86_VM_OS_LINUX_X86_HPP

  static void setup_fpu();
  static bool supports_sse();

  static jlong rdtsc();

  static bool is_allocatable(size_t bytes);

  // Used to register dynamic code cache area with the OS
  // Note: Currently only used in 64 bit Windows implementations
  static bool register_code_area(char *low, char *high) { return true; }

  /*
   * Work-around for broken NX emulation using CS limit, Red Hat patch "Exec-Shield"
   * (IA32 only).
   *
   * Map and execute at a high VA to prevent CS lazy updates race with SMP MM
   * invalidation.Further code generation by the JVM will no longer cause CS limit
   * updates.
   *
   * Affects IA32: RHEL 5 & 6, Ubuntu 10.04 (LTS), 10.10, 11.04, 11.10, 12.04.
   * @see JDK-8023956
   */
  static void workaround_expand_exec_shield_cs_limit();

#endif // OS_CPU_LINUX_X86_VM_OS_LINUX_X86_HPP