esp-idf/components/esp_system/ld/esp32/sections.ld.in

/*
 * SPDX-FileCopyrightText: 2021 Espressif Systems (Shanghai) CO LTD
 *
 * SPDX-License-Identifier: Apache-2.0
 */

#include "ld.common"

/* Default entry point */
ENTRY(call_start_cpu0);

SECTIONS
{
  /**
   * RTC fast memory holds RTC wake stub code,
   * including from any source file named rtc_wake_stub*.c
   */
  .rtc.text :
  {
    ALIGNED_SYMBOL(4, _rtc_text_start)

    mapping[rtc_text]

    *rtc_wake_stub*.*(.literal .text .literal.* .text.*)

    _rtc_text_end = ABSOLUTE(.);
  } > rtc_iram_seg

  /**
   * This section is required to skip rtc.text area because rtc_iram_seg and
   * rtc_data_seg are reflect the same address space on different buses.
   */
  .rtc.dummy :
  {
    _rtc_dummy_start = ABSOLUTE(.);
    _rtc_fast_start = ABSOLUTE(.);

    . = SIZEOF(.rtc.text);

    _rtc_dummy_end = ABSOLUTE(.);
  } > rtc_data_seg

  /**
   * This section located in RTC FAST Memory area.
   * It holds data marked with RTC_FAST_ATTR attribute.
   * See the file "esp_attr.h" for more information.
   */
  .rtc.force_fast :
  {
    ALIGNED_SYMBOL(4, _rtc_force_fast_start)

    mapping[rtc_force_fast]

    *(.rtc.force_fast .rtc.force_fast.*)

    ALIGNED_SYMBOL(4, _rtc_force_fast_end)
  } > rtc_data_seg

  /**
   * RTC data section holds RTC wake stub
   * data/rodata, including from any source file
   * named rtc_wake_stub*.c and the data marked with
   * RTC_DATA_ATTR, RTC_RODATA_ATTR attributes.
   * The memory location of the data is dependent on
   * CONFIG_ESP32_RTCDATA_IN_FAST_MEM option.
   */
  .rtc.data :
  {
    _rtc_data_start = ABSOLUTE(.);

    mapping[rtc_data]

    *rtc_wake_stub*.*(.data .rodata .data.* .rodata.*)

    _rtc_data_end = ABSOLUTE(.);
  } > rtc_data_location

  /* RTC bss, from any source file named rtc_wake_stub*.c */
  .rtc.bss (NOLOAD) :
  {
    _rtc_bss_start = ABSOLUTE(.);

    *rtc_wake_stub*.*(.bss .bss.*)
    *rtc_wake_stub*.*(COMMON)

    mapping[rtc_bss]

    _rtc_bss_end = ABSOLUTE(.);
  } > rtc_data_location

  /**
   * This section holds data that should not be initialized at power up
   * and will be retained during deep sleep.
   * User data marked with RTC_NOINIT_ATTR will be placed
   * into this section. See the file "esp_attr.h" for more information.
   * The memory location of the data is dependent on
   * CONFIG_ESP32_RTCDATA_IN_FAST_MEM option.
   */
  .rtc_noinit (NOLOAD):
  {
    ALIGNED_SYMBOL(4, _rtc_noinit_start)

    *(.rtc_noinit .rtc_noinit.*)

    ALIGNED_SYMBOL(4, _rtc_noinit_end)
  } > rtc_data_location

  /**
   * This section located in RTC SLOW Memory area.
   * It holds data marked with RTC_SLOW_ATTR attribute.
   * See the file "esp_attr.h" for more information.
   */
  .rtc.force_slow :
  {
    ALIGNED_SYMBOL(4, _rtc_force_slow_start)

    *(.rtc.force_slow .rtc.force_slow.*)

    ALIGNED_SYMBOL(4, _rtc_force_slow_end)
  } > rtc_slow_seg

  /**
   * This section holds RTC FAST data that should have fixed addresses.
   * The data are not initialized at power-up and are retained during deep
   * sleep.
   */
  .rtc_fast_reserved (NOLOAD):
  {
    ALIGNED_SYMBOL(4, _rtc_fast_reserved_start)

    /**
     * New data can only be added here to ensure existing data are not moved.
     * Because data have adhered to the end of the segment and code is relied
     * on it.
     * >> put new data here <<
     */

    KEEP(*(.bootloader_data_rtc_mem .bootloader_data_rtc_mem.*))

    _rtc_fast_reserved_end = ABSOLUTE(.);
  } > rtc_fast_reserved_seg

  _rtc_fast_reserved_length = _rtc_fast_reserved_end - _rtc_fast_reserved_start;
  ASSERT((_rtc_fast_reserved_length <= LENGTH(rtc_fast_reserved_seg)),
          "RTC FAST reserved segment data does not fit.")

  /**
   * This section holds RTC SLOW data that should have fixed addresses.
   * The data are not initialized at power-up and are retained during deep
   * sleep.
   */
  .rtc_slow_reserved (NOLOAD):
  {
    ALIGNED_SYMBOL(4, _rtc_slow_reserved_start)

    /**
     * New data can only be added here to ensure existing data are not moved.
     * Because data have adhered to the end of the segment and code is relied
     * on it.
     * >> put new data here <<
     */

    *(.rtc_timer_data_in_rtc_mem .rtc_timer_data_in_rtc_mem.*)

    _rtc_slow_reserved_end = ABSOLUTE(.);
  } > rtc_slow_reserved_seg

  _rtc_slow_reserved_length = _rtc_slow_reserved_end - _rtc_slow_reserved_start;
  _rtc_reserved_length = _rtc_slow_reserved_length;
  ASSERT((_rtc_slow_reserved_length <= LENGTH(rtc_slow_reserved_seg)),
          "RTC SLOW reserved segment data does not fit.")

  /* Get size of rtc slow data based on rtc_data_location alias */
  _rtc_slow_length = (ORIGIN(rtc_slow_seg) == ORIGIN(rtc_data_location))
                        ? (_rtc_force_slow_end - _rtc_data_start)
                        : (_rtc_force_slow_end - _rtc_force_slow_start);

  _rtc_fast_length = (ORIGIN(rtc_slow_seg) == ORIGIN(rtc_data_location))
                        ? (_rtc_force_fast_end - _rtc_fast_start)
                        : (_rtc_noinit_end - _rtc_fast_start);

  ASSERT((_rtc_slow_length <= LENGTH(rtc_slow_seg)),
          "RTC_SLOW segment data does not fit.")

  ASSERT((_rtc_fast_length <= LENGTH(rtc_data_seg)),
          "RTC_FAST segment data does not fit.")

  /* Send .iram0 code to iram */
  .iram0.vectors :
  {
    _iram_start = ABSOLUTE(.);
    /* Vectors go to IRAM */
    _vector_table = ABSOLUTE(.);
    . = 0x0;
    KEEP(*(.WindowVectors.text));
    . = 0x180;
    KEEP(*(.Level2InterruptVector.text));
    . = 0x1c0;
    KEEP(*(.Level3InterruptVector.text));
    . = 0x200;
    KEEP(*(.Level4InterruptVector.text));
    . = 0x240;
    KEEP(*(.Level5InterruptVector.text));
    . = 0x280;
    KEEP(*(.DebugExceptionVector.text));
    . = 0x2c0;
    KEEP(*(.NMIExceptionVector.text));
    . = 0x300;
    KEEP(*(.KernelExceptionVector.text));
    . = 0x340;
    KEEP(*(.UserExceptionVector.text));
    . = 0x3C0;
    KEEP(*(.DoubleExceptionVector.text));
    . = 0x400;
    _invalid_pc_placeholder = ABSOLUTE(.);
    *(.*Vector.literal)

    *(.UserEnter.literal);
    *(.UserEnter.text);
    . = ALIGN (16);
    *(.entry.text)
    *(.init.literal)
    *(.init)

    _init_end = ABSOLUTE(.);
  } > iram0_0_seg

  .iram0.text :
  {
    /* Code marked as running out of IRAM */
    _iram_text_start = ABSOLUTE(.);

    mapping[iram0_text]

  } > iram0_0_seg

  .dram0.data :
  {
    _data_start = ABSOLUTE(.);
    *(.gnu.linkonce.d.*)
    *(.data1)
    *(.sdata)
    *(.sdata.*)
    *(.gnu.linkonce.s.*)
    *(.gnu.linkonce.s2.*)
    *(.jcr)

    mapping[dram0_data]

    _data_end = ABSOLUTE(.);
  } > dram0_0_seg

  /**
   * This section holds data that won't be initialised when startup.
   * This section locates in External RAM region.
   */
  .ext_ram_noinit (NOLOAD) :
  {
    _ext_ram_noinit_start = ABSOLUTE(.);

    *(.ext_ram_noinit*)

    ALIGNED_SYMBOL(4, _ext_ram_noinit_end)
  } > extern_ram_seg

  /**
   * This section holds data that should not be initialized at power up.
   * The section located in Internal SRAM memory region. The macro _NOINIT
   * can be used as attribute to place data into this section.
   * See the "esp_attr.h" file for more information.
   */
  .noinit (NOLOAD):
  {
    ALIGNED_SYMBOL(4, _noinit_start)

    *(.noinit .noinit.*)

    ALIGNED_SYMBOL(4, _noinit_end)
  } > dram0_0_seg

  /* External Memory BSS. (Variables with EXT_RAM_BSS_ATTR attribute). */
  .ext_ram.bss (NOLOAD) :
  {
    ALIGNED_SYMBOL(4, _ext_ram_bss_start)

    mapping[extern_ram]

    ALIGNED_SYMBOL(4, _ext_ram_bss_end)
  } > extern_ram_seg

  /* Shared RAM */
  .dram0.bss (NOLOAD) :
  {
    ALIGNED_SYMBOL(8, _bss_start)

    /**
     * ldgen places all bss-related data to mapping[dram0_bss]
     * (See components/esp_system/app.lf).
     */
    mapping[dram0_bss]

    ALIGNED_SYMBOL(8, _bss_end)
  } > dram0_0_seg

  ASSERT(((_bss_end - ORIGIN(dram0_0_seg)) <= LENGTH(dram0_0_seg)),
          "DRAM segment data does not fit.")

  .flash.appdesc : ALIGN(0x10)
  {
    /**
     * Mark flash.rodata start.
     * This can be used for mmu driver to maintain virtual address
     */
    _rodata_reserved_start = ABSOLUTE(.);
    _rodata_start = ABSOLUTE(.);

    /* !DO NOT PUT ANYTHING BEFORE THIS! */

    /* Should be the first.  App version info. */
    *(.rodata_desc .rodata_desc.*)
    /* Should be the second. Custom app version info. */
    *(.rodata_custom_desc .rodata_custom_desc.*)

    /**
     * Create an empty gap within this section. Thanks to this, the end of this
     * section will match .flah.rodata's begin address. Thus, both sections
     * will be merged when creating the final bin image.
     */
    . = ALIGN(ALIGNOF(.flash.rodata));
  } > default_rodata_seg
  ASSERT_SECTIONS_GAP(.flash.appdesc, .flash.rodata)

  .flash.rodata : ALIGN(0x10)
  {
    _flash_rodata_start = ABSOLUTE(.);

    mapping[flash_rodata]

    *(.irom1.text) /* catch stray ICACHE_RODATA_ATTR */
    *(.gnu.linkonce.r.*)
    *(.rodata1)

    /* C++ exception handlers table.  */
    ALIGNED_SYMBOL(4, __XT_EXCEPTION_TABLE_)
    *(.xt_except_table)
    *(.gcc_except_table .gcc_except_table.*)
    *(.gnu.linkonce.e.*)

    ALIGNED_SYMBOL(4, __XT_EXCEPTION_DESCS_)
    *(.xt_except_desc)
    *(.gnu.linkonce.h.*)
    __XT_EXCEPTION_DESCS_END__ = ABSOLUTE(.);
    *(.xt_except_desc_end)

#if CONFIG_COMPILER_CXX_EXCEPTIONS
    ALIGNED_SYMBOL(4, __eh_frame)
    KEEP(*(.eh_frame))
    /**
     * As we are not linking with crtend.o, which includes the CIE terminator
     * (see __FRAME_END__ in libgcc sources), it is manually provided here.
     */
    LONG(0);
#endif // CONFIG_COMPILER_CXX_EXCEPTIONS

    /**
     * C++ constructor tables.
     *
     * Excluding crtbegin.o/crtend.o since IDF doesn't use the toolchain crt.
     */
    ALIGNED_SYMBOL(4, __init_array_start)
    KEEP (*(EXCLUDE_FILE (*crtend.* *crtbegin.*) .ctors SORT(.ctors.*)))
    __init_array_end = ABSOLUTE(.);

    /* Addresses of memory regions reserved via SOC_RESERVE_MEMORY_REGION() */
    ALIGNED_SYMBOL(4, soc_reserved_memory_region_start)
    KEEP (*(.reserved_memory_address))
    soc_reserved_memory_region_end = ABSOLUTE(.);

    /* System init functions registered via ESP_SYSTEM_INIT_FN */
    ALIGNED_SYMBOL(4, _esp_system_init_fn_array_start)
    KEEP (*(SORT_BY_INIT_PRIORITY(.esp_system_init_fn.*)))
    _esp_system_init_fn_array_end = ABSOLUTE(.);

    _rodata_end = ABSOLUTE(.);

    /* Literals are also RO data. */
    _lit4_start = ABSOLUTE(.);
    *(*.lit4)
    *(.lit4.*)
    *(.gnu.linkonce.lit4.*)
    _lit4_end = ABSOLUTE(.);

    /* TLS data. */
    ALIGNED_SYMBOL(4, _thread_local_start)
    *(.tdata)
    *(.tdata.*)
    *(.tbss)
    *(.tbss.*)
    _thread_local_end = ABSOLUTE(.);
  } > default_rodata_seg

  _flash_rodata_align = ALIGNOF(.flash.rodata);

  /**
   * This section contains all the rodata that is not used
   * at runtime, helping to avoid an increase in binary size.
   */
  .flash.rodata_noload (NOLOAD) :
  {
    /**
     * This symbol marks the end of flash.rodata. It can be utilized by the MMU
     * driver to maintain the virtual address.
     * NOLOAD rodata may not be included in this section.
     */
    _rodata_reserved_end = ABSOLUTE(.);

    mapping[rodata_noload]
  } > default_rodata_seg

  .flash.text :
  {
    _stext = .;
    /**
     * Mark the start of flash.text.
     * This can be used by the MMU driver to maintain the virtual address.
     */
    _instruction_reserved_start = ABSOLUTE(.);
    _text_start = ABSOLUTE(.);

    mapping[flash_text]

    *(.stub)
    *(.gnu.warning)
    *(.gnu.linkonce.literal.* .gnu.linkonce.t.*.literal .gnu.linkonce.t.*)
    *(.irom0.text) /* catch stray ICACHE_RODATA_ATTR */

    /**
     * CPU will try to prefetch up to 16 bytes of of instructions.
     * This means that any configuration (e.g. MMU, PMS) must allow
     * safe access to up to 16 bytes after the last real instruction,
     * add dummy bytes to ensure this.
     */
    . += _esp_flash_mmap_prefetch_pad_size;

    _text_end = ABSOLUTE(.);
    /**
     * Mark the flash.text end.
     * This can be used for MMU driver to maintain virtual address.
     */
    _instruction_reserved_end = ABSOLUTE(.);
    _etext = .;

    /**
     * Similar to _iram_start, this symbol goes here so it is
     * resolved by addr2line in preference to the first symbol in
     * the flash.text segment.
     */
    _flash_cache_start = ABSOLUTE(0);
  } > default_code_seg

  /* Marks the end of IRAM code segment */
  .iram0.text_end (NOLOAD) :
  {
    ALIGNED_SYMBOL(4, _iram_text_end)
  } > iram0_0_seg

  .iram0.data :
  {
    ALIGNED_SYMBOL(4, _iram_data_start)

    mapping[iram0_data]

    _iram_data_end = ABSOLUTE(.);
  } > iram0_0_seg

  .iram0.bss (NOLOAD) :
  {
    ALIGNED_SYMBOL(4, _iram_bss_start)

    mapping[iram0_bss]

    _iram_bss_end = ABSOLUTE(.);
    ALIGNED_SYMBOL(4, _iram_end)
  } > iram0_0_seg

  /* Marks the end of data, bss and possibly rodata  */
  .dram0.heap_start (NOLOAD) :
  {
    /* Lowest possible start address for the heap */
    ALIGNED_SYMBOL(8, _heap_low_start)
  } > dram0_0_seg

  /**
   * This section will be used by the debugger and disassembler to get more
   * information about raw data present in the code.
   * Indeed, it may be required to add some padding at some points in the code
   * in order to align a branch/jump destination on a particular bound.
   * Padding these instructions will generate null bytes that shall be
   * interpreted as data, and not code by the debugger or disassembler.
   * This section will only be present in the ELF file, not in the final binary
   * For more details, check GCC-212
   */
  .xt.prop 0 :
  {
    KEEP (*(.xt.prop .xt.prop.* .gnu.linkonce.prop.*))
  }

  .xt.lit 0 :
  {
    KEEP (*(.xt.lit .xt.lit.* .gnu.linkonce.p.*))
  }

  /DISCARD/ :
  {
   *(.eh_frame_hdr)
#if !CONFIG_COMPILER_CXX_EXCEPTIONS
   *(.eh_frame)
#endif // !CONFIG_COMPILER_CXX_EXCEPTIONS
  }
}

ASSERT(((_iram_end - ORIGIN(iram0_0_seg)) <= LENGTH(iram0_0_seg)),
          "IRAM0 segment data does not fit.")

ASSERT(((_heap_low_start - ORIGIN(dram0_0_seg)) <= LENGTH(dram0_0_seg)),
          "DRAM segment data does not fit.")