nuttx/boards/arm/stm32h7/nucleo-h743zi/scripts/kernel.space.ld
Nathan Hartman 4716fc929d arch/stm32h7 - Fix HEAP clobbering static data in SRAM4
Normally, statically allocated data goes in .bss, followed by the
initial stack, followed by HEAP. However, any data that is statically
allocated in SRAM4 with __attribute__ ((section (".sram4"))) will
clobber, and be clobbered by, the HEAP.

On STM32H7, BDMA can only access SRAM4. Therefore any BDMA buffers (or
any other data) placed in SRAM4 will expose this problem. In one case,
this manifested as a failure of NSH to start, because the SPI6 BDMA
buffers clobbered the /dev/console inode structs, which the OS
allocated earlier.

This PR ensures that only the rest of SRAM4, after any static data, is
added to the heap. This PR also allows SRAM4 to be completely excluded
from the heap by a new Kconfig, CONFIG_STM32H7_SRAM4EXCLUDE, similar
to what CONFIG_STM32H7_DTCMEXCLUDE does for the DTCM region.

Change required in linker scripts:

Every STM32H7 linker script must replace this:

    .sram4 :
    {
    } > sram4

with this:

    .sram4_reserve (NOLOAD) :
    {
        *(.sram4)
        . = ALIGN(4);
        _sram4_heap_start = ABSOLUTE(.);
    } > sram4

or link will fail with: undefined reference to '_sram4_heap_start'.

The Release Notes should document this for users with out-of-tree
boards.

arch/arm/src/stm32h7/Kconfig:

    * Add config STM32H7_SRAM4EXCLUDE to allow excluding all of SRAM4
      from the HEAP.

arch/arm/src/stm32h7/stm32_allocateheap.c:

    * Only when including SRAM4 in the heap, define HAVE_SRAM4,
      SRAM4_START, SRAM4_END, and SRAM4_HEAP_START.

    * Add "Private Data" section.

    * Add extern for_sram4_heap_start, which must be defined in the
      board's linker script.

    * arm_addregion(): Only add SRAM4 to the heap when configured to
      do so, i.e., unless CONFIG_STM32H7_SRAM4EXCLUDE is defined, and
      only add the portion of SRAM4 that is past any static data.

boards/arm/stm32h7/nucleo-h743zi/scripts/flash.ld:
boards/arm/stm32h7/nucleo-h743zi/scripts/kernel.space.ld:
boards/arm/stm32h7/nucleo-h743zi2/scripts/flash.ld:
boards/arm/stm32h7/stm32h747i-disco/scripts/flash.ld:
boards/arm/stm32h7/stm32h747i-disco/scripts/kernel.space.ld:

    * Update all in-tree STM32H7 board linker scripts as described in
      "Change required in linker scripts" above.

Testing:

    * Successfully built all of the following configurations:

      nucleo-h743zi2:jumbo
      nucleo-h743zi2:nsh
      nucleo-h743zi:nxlines_oled
      nucleo-h743zi:elf
      nucleo-h743zi:otg_fs_host
      nucleo-h743zi:nsh
      nucleo-h743zi:netnsh
      nucleo-h743zi:pwm
      stm32h747i-disco:nsh

    * Tested with custom board.

    * nxstyle.

References:

[1] See the dev@nuttx.a.o mailing list discussion started 2021/03/25:
    "How to ensure HEAP will not overlap static DMA buffer?"
    https://lists.apache.org/thread.html/recf2bb9043f8c9f53c10917e2adb2ec64fe35dc5e6f9a695a7ac6ecc%40%3Cdev.nuttx.apache.org%3E

[2] See arm_addregion() in arch/arm/src/stm32h7/stm32_allocateheap.c

Thanks to Gregory Nutt and David Sidrane for suggestions and reviews.
2021-03-30 17:22:46 -03:00

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/****************************************************************************
* boards/arm/stm32h7/nucleo-h743zi/scripts/kernel.space.ld
*
* 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.
*
****************************************************************************/
/* NOTE: This depends on the memory.ld script having been included prior to
* this script.
*/
OUTPUT_ARCH(arm)
ENTRY(_stext)
SECTIONS
{
.text : {
_stext = ABSOLUTE(.);
*(.vectors)
*(.text .text.*)
*(.fixup)
*(.gnu.warning)
*(.rodata .rodata.*)
*(.gnu.linkonce.t.*)
*(.glue_7)
*(.glue_7t)
*(.got)
*(.gcc_except_table)
*(.gnu.linkonce.r.*)
_etext = ABSOLUTE(.);
} > kflash
.init_section : {
_sinit = ABSOLUTE(.);
*(.init_array .init_array.*)
_einit = ABSOLUTE(.);
} > kflash
.ARM.extab : {
*(.ARM.extab*)
} > kflash
__exidx_start = ABSOLUTE(.);
.ARM.exidx : {
*(.ARM.exidx*)
} > kflash
__exidx_end = ABSOLUTE(.);
_eronly = ABSOLUTE(.);
.data : {
_sdata = ABSOLUTE(.);
*(.data .data.*)
*(.gnu.linkonce.d.*)
CONSTRUCTORS
. = ALIGN(4);
_edata = ABSOLUTE(.);
} > ksram AT > kflash
.bss : {
_sbss = ABSOLUTE(.);
*(.bss .bss.*)
*(.gnu.linkonce.b.*)
*(COMMON)
. = ALIGN(4);
_ebss = ABSOLUTE(.);
} > ksram
/* Emit the the D3 power domain section for locating BDMA data
*
* Static data with __attribute__ ((section (".sram4"))) will be located
* at start of SRAM4; the rest of SRAM4 will be added to the heap.
*/
.sram4_reserve (NOLOAD) :
{
*(.sram4)
. = ALIGN(4);
_sram4_heap_start = ABSOLUTE(.);
} > sram4
/* 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) }
}