nuttx/libs/libc/elf/gnu-elf.ld.in

/****************************************************************************
 * libs/libc/elf/gnu-elf.ld.in
 *
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.  The
 * ASF licenses this file to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance with the
 * License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
 * License for the specific language governing permissions and limitations
 * under the License.
 *
 ****************************************************************************/


#include <nuttx/config.h>

#if defined(CONFIG_BUILD_KERNEL) && defined(CONFIG_BINFMT_ELF_EXECUTABLE)
#  define __ASSEMBLY__
#  include <nuttx/addrenv.h>

#  define TEXT CONFIG_ARCH_TEXT_VBASE
#  define DATA CONFIG_ARCH_DATA_VBASE + ARCH_DATA_RESERVE_SIZE

#else
#  define TEXT 0x0
#  define DATA
#endif

/* A chip that selects CONFIG_ARCH_HAVE_TEXT_HEAP_WORD_ALIGNED_READ cannot
 * read its text region as data, so the loader puts every section that is not
 * executable in the data region.  A fully linked program is loaded at the
 * addresses in its own headers, so .rodata has to be linked there too: it
 * leads the data region and .data follows it.
 */

#ifdef CONFIG_ARCH_HAVE_TEXT_HEAP_WORD_ALIGNED_READ
#  define RODATA     DATA
#  define DATA_START
#else
#  define RODATA
#  define DATA_START DATA
#endif

#if defined(CONFIG_LIBC_ARCH_ELF_64BIT)
#  define SECTIONS_ALIGN 8
#else
#  define SECTIONS_ALIGN 4
#endif

/* An FDPIC module is a shared object whose read-only and writable segments
 * the loader places independently: the read-only one runs where the
 * filesystem already holds it and only the writable one is copied to RAM,
 * once per running instance.  So the two go into segments of their own, and
 * .dynamic is named, because a shared object is bound through it.
 *
 * Everything else is common, the symbols crt0.c walks included, so a module
 * is built and entered the same way whichever this is.
 */

#ifdef CONFIG_FDPIC
#  define PHDR_TEXT :text
#  define PHDR_DATA :data
#  define DATA_ALIGN . = ALIGN(0x1000);

/* .got.plt comes first, as in the linker's own script.  The linker places
 * the function descriptors of a lazy PLT on that assumption.
 */

#  define GOT_PLT *(.got.plt) *(.igot.plt)

PHDRS
{
  text    PT_LOAD FLAGS(5);    /* Read and execute */
  data    PT_LOAD FLAGS(6);    /* Read and write   */
  dynamic PT_DYNAMIC FLAGS(6);
}

#else
#  define PHDR_TEXT
#  define PHDR_DATA
#  define DATA_ALIGN
#  define GOT_PLT
#endif

SECTIONS
{
  .text TEXT :
    {
      _stext = . ;
      *(.literal)
      *(.literal.*)
      *(.text)
      *(.text.*)
      *(.gnu.warning)
      *(.stub)
      *(.glue_7)
      *(.glue_7t)
      *(.jcr)

      /* C++ support: the .init and .fini sections hold the logic that runs
       * the static constructors and destructors.
       */

      *(.gnu.linkonce.t.*)
      *(.init)
      *(.fini)
      . = ALIGN(SECTIONS_ALIGN);
      _etext = . ;
    } PHDR_TEXT

  .rodata RODATA :
    {
      _srodata = . ;
      *(.rodata)
      *(.rodata1)
      *(.rodata.*)
      *(.gnu.linkonce.r*)
      . = ALIGN(SECTIONS_ALIGN);
      _erodata = . ;
    } PHDR_TEXT

  .eh_frame :
    {
      KEEP (*(.eh_frame))
      *(.eh_frame.*)
    } PHDR_TEXT

#ifdef CONFIG_FDPIC
  /* DT_JMPREL names .rel.plt, so it is an output section of its own, after
   * the other dynamic relocations, as in the linker's own script.
   */

  .rel.dyn :
    {
      *(.rel.init)
      *(.rel.text .rel.text.*)
      *(.rel.fini)
      *(.rel.rodata .rel.rodata.*)
      *(.rel.data.rel.ro .rel.data.rel.ro.*)
      *(.rel.data .rel.data.*)
      *(.rel.ctors)
      *(.rel.dtors)
      *(.rel.got)
      *(.rel.bss .rel.bss.*)
      *(.rel.iplt)
    } PHDR_TEXT

  .rel.plt :
    {
      *(.rel.plt)
    } PHDR_TEXT
#endif

  DATA_ALIGN

  .data DATA_START :
    {
      _sdata = . ;
      *(.data)
      *(.data1)
      *(.data.*)
      *(.gnu.linkonce.d*)
      . = ALIGN(SECTIONS_ALIGN);
      _edata = . ;
    } PHDR_DATA

  .init_array :
    {
      _sinit = .;
      _sctors = .;
      KEEP(*(SORT_BY_INIT_PRIORITY(.init_array.*) SORT_BY_INIT_PRIORITY(.ctors.*)))
      KEEP(*(.init_array .ctors))
      . = ALIGN(SECTIONS_ALIGN);
      _einit = .;
      _ectors = .;
    } PHDR_DATA

  .fini_array :
    {
      _sfini = .;
      _sdtors = .;
      KEEP (*(.dtors))
      KEEP (*(.fini_array))
      KEEP (*(SORT(.fini_array.*)))
      . = ALIGN(SECTIONS_ALIGN);
      _efini = .;
      _edtors = .;
    } PHDR_DATA

#ifdef CONFIG_FDPIC
  .dynamic :
    {
      *(.dynamic)
    } :data :dynamic
#endif

  .got :
    {
      GOT_PLT
      *(.got*)
    } PHDR_DATA

  /* .bss holds no file content, so it comes last.  Everything ahead of it
   * has content, thus the writable segment's p_filesz stops where .bss
   * starts and the file does not carry it.
   */

  .bss :
    {
      _sbss = . ;
      *(.bss)
      *(.bss.*)
      *(.sbss)
      *(.sbss.*)
      *(.gnu.linkonce.b*)
      *(COMMON)
      . = ALIGN(SECTIONS_ALIGN);
      _ebss = . ;
    } PHDR_DATA

    /* Stabs debugging sections.    */

    .stab 0 : { *(.stab) }
    .stabstr 0 : { *(.stabstr) }
    .stab.excl 0 : { *(.stab.excl) }
    .stab.exclstr 0 : { *(.stab.exclstr) }
    .stab.index 0 : { *(.stab.index) }
    .stab.indexstr 0 : { *(.stab.indexstr) }
    .comment 0 : { *(.comment) }
    .debug_abbrev 0 : { *(.debug_abbrev) }
    .debug_info 0 : { *(.debug_info) }
    .debug_line 0 : { *(.debug_line) }
    .debug_pubnames 0 : { *(.debug_pubnames) }
    .debug_aranges 0 : { *(.debug_aranges) }
}