/*

 * Copyright 2007, 2008, 2009, 2010 Red Hat, Inc.

 * 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.

 *

 *

 */

// do not include precompiled header file

#include "incls/_os_linux_zero.cpp.incl"

address os::current_stack_pointer() {

  address dummy = (address) &dummy;

  return dummy;

}

frame os::get_sender_for_C_frame(frame* fr) {

  ShouldNotCallThis();

}

frame os::current_frame() {

  // The only thing that calls this is the stack printing code in

  // VMError::report:

  //   - Step 110 (printing stack bounds) uses the sp in the frame

  //     to determine the amount of free space on the stack.  We

  //     set the sp to a close approximation of the real value in

  //     order to allow this step to complete.

  //   - Step 120 (printing native stack) tries to walk the stack.

  //     The frame we create has a NULL pc, which is ignored as an

  //     invalid frame.

  frame dummy = frame();

  dummy.set_sp((intptr_t *) current_stack_pointer());

  return dummy;

}

char* os::non_memory_address_word() {

  // Must never look like an address returned by reserve_memory,

  // even in its subfields (as defined by the CPU immediate fields,

  // if the CPU splits constants across multiple instructions).

#ifdef SPARC

  // On SPARC, 0 != %hi(any real address), because there is no

  // allocation in the first 1Kb of the virtual address space.

  return (char *) 0;

#else

  // This is the value for x86; works pretty well for PPC too.

  return (char *) -1;

#endif // SPARC

}

void os::initialize_thread() {

  // Nothing to do.

}

address os::Linux::ucontext_get_pc(ucontext_t* uc) {

  ShouldNotCallThis();

}

ExtendedPC os::fetch_frame_from_context(void* ucVoid,

                                        intptr_t** ret_sp,

                                        intptr_t** ret_fp) {

  ShouldNotCallThis();

}

frame os::fetch_frame_from_context(void* ucVoid) {

  ShouldNotCallThis();

}

extern "C" int

JVM_handle_linux_signal(int sig,

                        siginfo_t* info,

                        void* ucVoid,

                        int abort_if_unrecognized) {

  ucontext_t* uc = (ucontext_t*) ucVoid;

  Thread* t = ThreadLocalStorage::get_thread_slow();

  SignalHandlerMark shm(t);

  // Note: it's not uncommon that JNI code uses signal/sigset to

  // install then restore certain signal handler (e.g. to temporarily

  // block SIGPIPE, or have a SIGILL handler when detecting CPU

  // type). When that happens, JVM_handle_linux_signal() might be

  // invoked with junk info/ucVoid. To avoid unnecessary crash when

  // libjsig is not preloaded, try handle signals that do not require

  // siginfo/ucontext first.

  if (sig == SIGPIPE || sig == SIGXFSZ) {

    // allow chained handler to go first

    if (os::Linux::chained_handler(sig, info, ucVoid)) {

      return true;

    } else {

      if (PrintMiscellaneous && (WizardMode || Verbose)) {

        char buf[64];

        warning("Ignoring %s - see bugs 4229104 or 646499219",

                os::exception_name(sig, buf, sizeof(buf)));

      }

      return true;

    }

  }

  JavaThread* thread = NULL;

  VMThread* vmthread = NULL;

  if (os::Linux::signal_handlers_are_installed) {

    if (t != NULL ){

      if(t->is_Java_thread()) {

        thread = (JavaThread*)t;

      }

      else if(t->is_VM_thread()){

        vmthread = (VMThread *)t;

      }

    }

  }

  if (info != NULL && thread != NULL) {

    // Handle ALL stack overflow variations here

    if (sig == SIGSEGV) {

      address addr = (address) info->si_addr;

      // check if fault address is within thread stack

      if (addr < thread->stack_base() &&

          addr >= thread->stack_base() - thread->stack_size()) {

        // stack overflow

        if (thread->in_stack_yellow_zone(addr)) {

          thread->disable_stack_yellow_zone();

          ShouldNotCallThis();

        }

        else if (thread->in_stack_red_zone(addr)) {

          thread->disable_stack_red_zone();

          ShouldNotCallThis();

        }

        else {

          // Accessing stack address below sp may cause SEGV if

          // current thread has MAP_GROWSDOWN stack. This should

          // only happen when current thread was created by user

          // code with MAP_GROWSDOWN flag and then attached to VM.

          // See notes in os_linux.cpp.

          if (thread->osthread()->expanding_stack() == 0) {

            thread->osthread()->set_expanding_stack();

            if (os::Linux::manually_expand_stack(thread, addr)) {

              thread->osthread()->clear_expanding_stack();

              return true;

            }

            thread->osthread()->clear_expanding_stack();

          }

          else {

            fatal("recursive segv. expanding stack.");

          }

        }

      }

    }

    /*if (thread->thread_state() == _thread_in_Java) {

      ShouldNotCallThis();

    }

    else*/ if (thread->thread_state() == _thread_in_vm &&

               sig == SIGBUS && thread->doing_unsafe_access()) {

      ShouldNotCallThis();

    }

    // jni_fast_Get<Primitive>Field can trap at certain pc's if a GC

    // kicks in and the heap gets shrunk before the field access.

    /*if (sig == SIGSEGV || sig == SIGBUS) {

      address addr = JNI_FastGetField::find_slowcase_pc(pc);

      if (addr != (address)-1) {

        stub = addr;

      }

    }*/

    // Check to see if we caught the safepoint code in the process

    // of write protecting the memory serialization page.  It write

    // enables the page immediately after protecting it so we can

    // just return to retry the write.

    if (sig == SIGSEGV &&

        os::is_memory_serialize_page(thread, (address) info->si_addr)) {

      // Block current thread until permission is restored.

      os::block_on_serialize_page_trap();

      return true;

    }

  }

  // signal-chaining

  if (os::Linux::chained_handler(sig, info, ucVoid)) {

     return true;

  }

  if (!abort_if_unrecognized) {

    // caller wants another chance, so give it to him

    return false;

  }

#ifndef PRODUCT

  if (sig == SIGSEGV) {

    fatal("\n#"

          "\n#    /--------------------\\"

          "\n#    | segmentation fault |"

          "\n#    \\---\\ /--------------/"

          "\n#        /"

          "\n#    [-]        |\\_/|    "

          "\n#    (+)=C      |o o|__  "

          "\n#    | |        =-*-=__\\ "

          "\n#    OOO        c_c_(___)");

  }

#endif // !PRODUCT

  const char *fmt = "caught unhandled signal %d";

  char buf[64];

  sprintf(buf, fmt, sig);

  fatal(buf);

}

void os::Linux::init_thread_fpu_state(void) {

  // Nothing to do

}

int os::Linux::get_fpu_control_word() {

  ShouldNotCallThis();

}

void os::Linux::set_fpu_control_word(int fpu) {

  ShouldNotCallThis();

}

bool os::is_allocatable(size_t bytes) {

#ifdef _LP64

  return true;

#else

  if (bytes < 2 * G) {

    return true;

  }

  char* addr = reserve_memory(bytes, NULL);

  if (addr != NULL) {

    release_memory(addr, bytes);

  }

  return addr != NULL;

#endif // _LP64

}

///////////////////////////////////////////////////////////////////////////////

// thread stack

size_t os::Linux::min_stack_allowed = 64 * K;

bool os::Linux::supports_variable_stack_size() {

  return true;

}

size_t os::Linux::default_stack_size(os::ThreadType thr_type) {

#ifdef _LP64

  size_t s = (thr_type == os::compiler_thread ? 4 * M : 1 * M);

#else

  size_t s = (thr_type == os::compiler_thread ? 2 * M : 512 * K);

#endif // _LP64

  return s;

}

size_t os::Linux::default_guard_size(os::ThreadType thr_type) {

  // Only enable glibc guard pages for non-Java threads

  // (Java threads have HotSpot guard pages)

  return (thr_type == java_thread ? 0 : page_size());

}

static void current_stack_region(address *bottom, size_t *size) {

  pthread_attr_t attr;

  int res = pthread_getattr_np(pthread_self(), &attr);

  if (res != 0) {

    if (res == ENOMEM) {

      vm_exit_out_of_memory(0, "pthread_getattr_np");

    }

    else {

      fatal(err_msg("pthread_getattr_np failed with errno = %d", res));

    }

  }

  address stack_bottom;

  size_t stack_bytes;

  res = pthread_attr_getstack(&attr, (void **) &stack_bottom, &stack_bytes);

  if (res != 0) {

    fatal(err_msg("pthread_attr_getstack failed with errno = %d", res));

  }

  address stack_top = stack_bottom + stack_bytes;

  // The block of memory returned by pthread_attr_getstack() includes

  // guard pages where present.  We need to trim these off.

  size_t page_bytes = os::Linux::page_size();

  assert(((intptr_t) stack_bottom & (page_bytes - 1)) == 0, "unaligned stack");

  size_t guard_bytes;

  res = pthread_attr_getguardsize(&attr, &guard_bytes);

  if (res != 0) {

    fatal(err_msg("pthread_attr_getguardsize failed with errno = %d", res));

  }

  int guard_pages = align_size_up(guard_bytes, page_bytes) / page_bytes;

  assert(guard_bytes == guard_pages * page_bytes, "unaligned guard");

#ifdef IA64

  // IA64 has two stacks sharing the same area of memory, a normal

  // stack growing downwards and a register stack growing upwards.

  // Guard pages, if present, are in the centre.  This code splits

  // the stack in two even without guard pages, though in theory

  // there's nothing to stop us allocating more to the normal stack

  // or more to the register stack if one or the other were found

  // to grow faster.

  int total_pages = align_size_down(stack_bytes, page_bytes) / page_bytes;

  stack_bottom += (total_pages - guard_pages) / 2 * page_bytes;

#endif // IA64

  stack_bottom += guard_bytes;

  pthread_attr_destroy(&attr);

  // The initial thread has a growable stack, and the size reported

  // by pthread_attr_getstack is the maximum size it could possibly

  // be given what currently mapped.  This can be huge, so we cap it.

  if (os::Linux::is_initial_thread()) {

    stack_bytes = stack_top - stack_bottom;

    if (stack_bytes > JavaThread::stack_size_at_create())

      stack_bytes = JavaThread::stack_size_at_create();

    stack_bottom = stack_top - stack_bytes;

  }

  assert(os::current_stack_pointer() >= stack_bottom, "should do");

  assert(os::current_stack_pointer() < stack_top, "should do");

  *bottom = stack_bottom;

  *size = stack_top - stack_bottom;

}

address os::current_stack_base() {

  address bottom;

  size_t size;

  current_stack_region(&bottom, &size);

  return bottom + size;

}

size_t os::current_stack_size() {

  // stack size includes normal stack and HotSpot guard pages

  address bottom;

  size_t size;

  current_stack_region(&bottom, &size);

  return size;

}

/////////////////////////////////////////////////////////////////////////////

// helper functions for fatal error handler

void os::print_context(outputStream* st, void* context) {

  ShouldNotCallThis();

}

/////////////////////////////////////////////////////////////////////////////

// Stubs for things that would be in linux_zero.s if it existed.

// You probably want to disassemble these monkeys to check they're ok.

extern "C" {

  int SpinPause() {

  }

  int SafeFetch32(int *adr, int errValue) {

    int value = errValue;

    value = *adr;

    return value;

  }

  intptr_t SafeFetchN(intptr_t *adr, intptr_t errValue) {

    intptr_t value = errValue;

    value = *adr;

    return value;

  }

  void _Copy_conjoint_jshorts_atomic(jshort* from, jshort* to, size_t count) {

    if (from > to) {

      jshort *end = from + count;

      while (from < end)

        *(to++) = *(from++);

    }

    else if (from < to) {

      jshort *end = from;

      from += count - 1;

      to   += count - 1;

      while (from >= end)

        *(to--) = *(from--);

    }

  }

  void _Copy_conjoint_jints_atomic(jint* from, jint* to, size_t count) {

    if (from > to) {

      jint *end = from + count;

      while (from < end)

        *(to++) = *(from++);

    }

    else if (from < to) {

      jint *end = from;

      from += count - 1;

      to   += count - 1;

      while (from >= end)

        *(to--) = *(from--);

    }

  }

  void _Copy_conjoint_jlongs_atomic(jlong* from, jlong* to, size_t count) {

    if (from > to) {

      jlong *end = from + count;

      while (from < end)

        os::atomic_copy64(from++, to++);

    }

    else if (from < to) {

      jlong *end = from;

      from += count - 1;

      to   += count - 1;

      while (from >= end)

        os::atomic_copy64(from--, to--);

    }

  }

  void _Copy_arrayof_conjoint_bytes(HeapWord* from,

                                    HeapWord* to,

                                    size_t    count) {

    ShouldNotCallThis();

  }

  void _Copy_arrayof_conjoint_jshorts(HeapWord* from,

                                      HeapWord* to,

                                      size_t    count) {

    ShouldNotCallThis();

  }

  void _Copy_arrayof_conjoint_jints(HeapWord* from,

                                    HeapWord* to,

                                    size_t    count) {

    ShouldNotCallThis();

  }

  void _Copy_arrayof_conjoint_jlongs(HeapWord* from,

                                     HeapWord* to,

                                     size_t    count) {

    ShouldNotCallThis();

  }

};

/////////////////////////////////////////////////////////////////////////////

// Implementations of atomic operations not supported by processors.

//  -- http://gcc.gnu.org/onlinedocs/gcc-4.2.1/gcc/Atomic-Builtins.html

#ifndef _LP64

extern "C" {

  long long unsigned int __sync_val_compare_and_swap_8(

    volatile void *ptr,

    long long unsigned int oldval,

    long long unsigned int newval) {

    ShouldNotCallThis();

  }

};

#endif // !_LP64