hw/ip/otbn/data/otbn.ld.tpl

/* Copyright lowRISC contributors. */
/* Licensed under the Apache License, Version 2.0, see LICENSE for details. */
/* SPDX-License-Identifier: Apache-2.0 */
/*

  OTBN has a pure Harvard architecture, with instruction and data
  memory both starting at address 0.

  This linker script template is interpolated by otbn_ld.py after it gets
  the LMAs and memory sizes from otbn.hjson.

*/
MEMORY
{
    imem (x)  : ORIGIN = 0, LENGTH = ${imem_length}
    dmem (rw) : ORIGIN = 0, LENGTH = ${dmem_bus_length}
    dmem_scratch (rw) : ORIGIN = ${dmem_bus_length}, LENGTH = ${dmem_length - dmem_bus_length}

    /*
      LMA addresses (for VMAs in imem/dmem, respectively)

      Note that the DMEM load region is the first 3kiB of DMEM itself,
      to model the fact that OTBN can write to the whole region but
      only the first 3kiB are bus-accessible.
    */
    imem_load (rw) : ORIGIN = ${imem_lma}, LENGTH = ${imem_length}
    dmem_load (rw) : ORIGIN = ${dmem_lma}, LENGTH = ${dmem_bus_length}
}

SECTIONS
{
    .text ORIGIN(imem) : ALIGN(4)
    {
        _imem_start = .;
        KEEP(*(.text.start*))
        *(.text*)

        /* Align section end. Shouldn't really matter, but might make binary
           blobs a bit easier to work with. */
        . = ALIGN(4);

        _imem_end = .;
    } >imem AT>imem_load

    .data ORIGIN(dmem) : ALIGN(32)
    {
        _dmem_data_start = .;
        *(.data*)

        /* Align section end (see note in .text section) */
        . = ALIGN(4);

        _dmem_data_end = .;
    } >dmem AT>dmem_load

    .bss : ALIGN(32)
    {
        _dmem_bss_start = .;
        *(.bss*)

        /* Align section end (see note in .text section) */
        . = ALIGN(4);

        _dmem_bss_end = .;
    } >dmem AT>dmem_load

    /* This matches the offset *in DMEM* of the .bss section. */
    _dmem_bss_offset = ADDR(.bss) - ADDR(.data);

    .scratchpad ORIGIN(dmem_scratch) (NOLOAD) : ALIGN(32)
    {
        *(.scratch*)
    } >dmem
}