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 #ifndef OS_CPU_LINUX_X86_VM_THREADLS_LINUX_X86_HPP
  26 #define OS_CPU_LINUX_X86_VM_THREADLS_LINUX_X86_HPP
  27 
  28   // Processor dependent parts of ThreadLocalStorage
  29 
  30 #if !defined(AMD64) && !defined(MINIMIZE_RAM_USAGE)
  31 
  32   // map stack pointer to thread pointer - see notes in threadLS_linux_x86.cpp
  33   #define SP_BITLENGTH  32
  34   #define PAGE_SHIFT    12
  35   #define PAGE_SIZE     (1UL << PAGE_SHIFT)
  36   static Thread* _sp_map[1UL << (SP_BITLENGTH - PAGE_SHIFT)];
  37 
  38 public:
  39 
  40   static Thread** sp_map_addr() { return _sp_map; }
  41 
  42   static Thread* thread() {
  43     uintptr_t sp;
  44     __asm__ volatile ("movl %%esp, %0" : "=r" (sp));
  45     return _sp_map[sp >> PAGE_SHIFT];
  46   }
  47 
  48 #else
  49 
  50 public:
  51 
  52    static Thread* thread() {
  53      return (Thread*) os::thread_local_storage_at(thread_index());
  54    }
  55 
  56 #endif // AMD64 || MINIMIZE_RAM_USAGE
  57 
  58 #endif // OS_CPU_LINUX_X86_VM_THREADLS_LINUX_X86_HPP