incubator-nuttx/libs/libxx/libxx__gnu_unwind_find_exid...

109 lines
4.5 KiB
C++

//***************************************************************************
// libs/libxx/libxx__gnu_unwind_find_exidx.cxx
//
// Copyright (C) 2015 Gregory Nutt. All rights reserved.
// Author: Gregory Nutt <gnutt@nuttx.org>
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions
// are met:
//
// 1. Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// 2. Redistributions in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in
// the documentation and/or other materials provided with the
// distribution.
// 3. Neither the name NuttX nor the names of its contributors may be
// used to endorse or promote products derived from this software
// without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
// FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
// COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
// INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
// BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
// OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
// AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
// LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
// ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
// POSSIBILITY OF SUCH DAMAGE.
//
//***************************************************************************
//***************************************************************************
// Included Files
//***************************************************************************
#include <nuttx/elf.h>
#include "libxx__gnu_unwind_find_exidx.hxx"
//***************************************************************************
// Pre-processor Definitions
//***************************************************************************
//***************************************************************************
// Private Data
//***************************************************************************
//***************************************************************************
// Operators
//***************************************************************************
//***************************************************************************
// Name: __gnu_Unwind_Find_exidx
//
// Description:
// This function is called (if exists) by the gcc generated unwind
// run-time in order to retrieve an alternative .ARM.exidx Exception
// index section.
// This is the case for an ELF module loaded by the elf binary loader.
// It is needed to support exception handling for loadable ELF modules.
//
// NOTES:
//
// 1. The section to be searched is chosen by the address of the calling
// site: if we are in a runtime loaded ELF, the code will be executed
// in ram ( > 0x20000000 ) otherwise we will be executing code from
// flash (0x08000000) (running nuttx from ram will break this logic)
//
// 2. __exidx_start and __exidx_end refers to main nuttx elf image and
// are defined in its linker script.
//
// 2. __exidx_start_elf and __exidx_end_elf refers to the elf module
// loaded by the elf binary loader, and are initialized at run-time.
//
// 3. TODO: if nuttx itself is running from ram, this logic will not work
//
// 4. TODO: in order to support multiple elf modules running at the same
// time, this error logic needs to be extended to store multiple
// start/end ranges that refers to the loaded binaries.
//
//***************************************************************************
extern "C"
{
int up_init_exidx(Elf_Addr start, Elf_Word size)
{
__exidx_start_elf = (__EIT_entry *) start;
__exidx_end_elf = __exidx_start_elf + size;
return 0;
}
_Unwind_Ptr __gnu_Unwind_Find_exidx (_Unwind_Ptr return_address, int *nrecp)
{
if (return_address < 0x20000000)
{
*nrecp = &__exidx_end - &__exidx_start;
return (_Unwind_Ptr) &__exidx_start;
}
else
{
*nrecp = (__exidx_end_elf - __exidx_start_elf) / sizeof(__EIT_entry);
return (_Unwind_Ptr) __exidx_start_elf;
}
}
}