1 /*
 2  * Copyright (c) 1999, 2019, 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
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23  */
24 
25 #ifndef OS_CPU_LINUX_X86_OS_LINUX_X86_HPP
26 #define OS_CPU_LINUX_X86_OS_LINUX_X86_HPP
27 
28   static void setup_fpu();
29   static bool supports_sse();
30 
31   static jlong rdtsc();
32 
33   static bool is_allocatable(size_t bytes);
34 
35   // Used to register dynamic code cache area with the OS
36   // Note: Currently only used in 64 bit Windows implementations
37   static bool register_code_area(char *low, char *high) { return true; }
38 
39   /*
40    * Work-around for broken NX emulation using CS limit, Red Hat patch "Exec-Shield"
41    * (IA32 only).
42    *
43    * Map and execute at a high VA to prevent CS lazy updates race with SMP MM
44    * invalidation.Further code generation by the JVM will no longer cause CS limit
45    * updates.
46    *
47    * Affects IA32: RHEL 5 & 6, Ubuntu 10.04 (LTS), 10.10, 11.04, 11.10, 12.04.
48    * @see JDK-8023956
49    */
50   static void workaround_expand_exec_shield_cs_limit();
51 
52 #endif // OS_CPU_LINUX_X86_OS_LINUX_X86_HPP