Script to relocate code/data/bss sections to different memory types. #10892

varun-sha · 2018-10-28T21:35:32Z

This script will relocate .text .data and .bss sections from
required files and places it in the required memory region. This
memory region and file are given to this python script in the form
of a string. This script is always invoked from inside cmake.

The main goal of this script is to provide a robust way to re-order
the memory contents without actually having to modify the code.
In simple terms this script will do the job of
__attribute__((section("name"))) for a bunch of files together.

This patch also creates a rule in the cmake to trigger the generation
of linker_relocate.ld and code_relocation.c files.
The linker_relocate.ld will create appropriate sections and will
link the required functions or variables from all the selected
files.
The code_relocation.c will have code that is needed for
initializing data sections and copy of text sections(if XIP).
Also this will contain code that is needed for zeroing of bss.

The procedure to invoke this feature is:
1. Enable CONFIG_CODE_RELOCATION in the prj.conf
2. Inside the CMakeLists.txt the following needs to be added
   immediately after cmake_minimum_required()

   include($ENV{ZEPHYR_BASE}/cmake/section_relocation.cmake
           NO_POLICY_SCOPE)

3. Before the inclusion of boilerplate.cmake we need to mention
   all the files that need to get relocated.

   zephyr_kernel_code_relocate(src/*.c SRAM2)

   Where the first argument is the file/files and the second
   argument is the memory where it has be placed.
   NOTE: The file argument supports limited regular expressions.

NOTE: Step 2 is needed only once. But step 3 can be done as many
times as required. But step 3 has to be performed before the
inclusion of boilerplate.cmake.

codecov-io · 2018-10-28T22:07:10Z

Codecov Report

Merging #10892 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master   #10892   +/-   ##
=======================================
  Coverage   51.43%   51.43%           
=======================================
  Files         231      231           
  Lines       28751    28751           
  Branches     7152     7152           
=======================================
  Hits        14789    14789           
  Misses      11144    11144           
  Partials     2818     2818

Impacted Files	Coverage Δ
kernel/init.c	`72.13% <ø> (ø)`	⬆️

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SebastianBoe

Script to relocate code/data/bss sections for particular library/app
to another memory(ccm and aon etc) or to other memory partition.

Code should not be generated unless there is no reasonable way
to write code in it's source langauge.

Could you elaborate on our options for satisfying the same use-case by
writing linker script code?

I would like to see that it was attempted, and then deemed unfeasible to write code
before one decided to generate code.

varun-sha · 2018-10-29T13:08:13Z

This are my initial commits with basic testing done on qemu_cortex_m3 & relocation checked with readelf, zephyr.map/lst files.

To test script, i have created generic sram2 partition(just for test purpose), pls check below commit:-
varun-sha@b61f3bd

to relocate particular file to particular memory or partition , add below property in CMakeLists.txt
set_property(GLOBAL PROPERTY CODE_DATA_RELOCATION_STRINGS "SRAM2:src/main.c")

varun-sha · 2018-10-30T09:20:36Z

@SebastianBoe

Code should not be generated unless there is no reasonable way
to write code in it's source langauge.

Could you elaborate on our options for satisfying the same use-case by
writing linker script code?

would like to see that it was attempted, and then deemed unfeasible to write code
before one decided to generate code.

[Varun]=> Function/variables can be placed into specfic memory using source code by http://www.keil.com/support/man/docs/armlink/armlink_pge1362066000009.htm
But this approach will clutter code with ifdef's depending on which memory it should go & is not generic if we want to support multiple memory types/partition's.

So i have created scripts/gen_relocate_app.py which will create another ld file called linker_relocate.ld, which has all sections which need to be relocated, extracted from obj files & will be included in main linker.cmd. It will be enabled/disabled based on property values set in CMakeLists.txt..
All of this is done after compilation and before linking.

SebastianBoe · 2018-10-31T12:53:53Z

I see this is marked as RFC, what more work needs to be done before it is in a merge-able state?

CMakeLists.txt

cmake/section_relocation.cmake

scripts/gen_relocate_app.py

SebastianBoe · 2018-10-31T13:28:50Z

But this approach will clutter code with ifdef's depending on which memory it should go & is not generic if we want to support multiple memory types/partition's.

I see that this is limited in scope to the 'app' libraries object files.

Note that for the 'app' library one can use custom-rwdata.ld etc., see the Kconfig options in zephyr/misc/Kconfig.

This is not affected by "cluttering the code with ifdef's" as far as I can tell. Unless we can prove that there are problems with using the existing mechanism we should not introduce a code generator that covers an already covered use-case.

varun-sha · 2018-11-07T19:36:14Z

But this approach will clutter code with ifdef's depending on which memory it should go & is not generic if we want to support multiple memory types/partition's.

I see that this is limited in scope to the 'app' libraries object files.

Note that for the 'app' library one can use custom-rwdata.ld etc., see the Kconfig options in zephyr/misc/Kconfig.

This is not affected by "cluttering the code with ifdef's" as far as I can tell. Unless we can prove that there are problems with using the existing mechanism we should not introduce a code generator that covers an already covered use-case.

Its not specific to "app" only, kernel files can be be relocated if zephyr_kernel_code_relocate(file mem_type) is called from kernel specific CMakeList.txt

varun-sha · 2018-11-07T19:39:05Z

I see this is marked as RFC, what more work needs to be done before it is in a merge-able state?

This was initial commit to get reviewers feedback , was initially tested on qemu_cortex_m3.
Currently being tested on Cortex M7 and have found few issues.. i,e RFC

dbkinder

This document is better placed in the Developer Guide area rather than in the top-level toc.

doc/code_data_relocation/relocation.rst

dbkinder · 2018-11-28T22:58:55Z

doc/code_data_relocation/relocation.rst

+
+Overview
+********
+This script will relocate .text, .rodata, .data and .bss sections from


Suggested change

This script will relocate .text, .rodata, .data and .bss sections from

This script will relocate .text, .rodata, .data, and .bss sections from

@dbkinder I don't understand why there needs to be a comma before an "and" in this case. Hence I haven't fixed this.
Others are done. Please re-review.

With so many contributors, we've tried to standardize on some simple editorial guidelines such as using English spellings (vs. British) and using the Microsoft Writing Style Guide and Merriam-Webster Dictionary as guidelines. Use of the Oxford (or serial) comma is the recommendation, to avoid potential confusion with lists.

ohh okay. Changed to the recommendation.
@dbkinder Please re-review.

doc/code_data_relocation/relocation.rst

doc/index.rst

doc/code_data_relocation/relocation.rst

dbkinder

LGTM, thanks.

nashif · 2018-12-04T06:04:28Z

kernel/Kconfig

@@ -279,6 +279,13 @@ config WAITQ_DUMB

 endchoice # WAITQ_ALGORITHM

+config CODE_DATA_RELOCATION


why is this under kernel/Kconfig? Please move out of here to Kconfig.zephyr under linker options for example.

nashif · 2018-12-04T06:05:27Z

kernel/Kconfig

+	depends on ARM
+	help
+	  When selected this will relocate .text, data and .bss sections from
+	  required files and places it in the required memory region.


required files? required by what? Maybe specified file.

nashif · 2018-12-04T06:06:32Z

samples/test_relocation/sample.yaml

+      regex:
+      - "Hello World! (.*)"
+    platform_whitelist: qemu_cortex_m3 mps2_an385 sam_e70_xplained
+    tags: introduction


tags: linker

nashif · 2018-12-04T06:06:51Z

samples/test_relocation/sample.yaml

@@ -0,0 +1,12 @@
+sample:
+  description: Code data relocation Sample
+  name: test relocation


name: Code Relocation

nashif · 2018-12-04T06:07:58Z

samples/test_relocation/CMakeLists.txt

@@ -0,0 +1,18 @@
+cmake_minimum_required(VERSION 3.8.2)


Move this sample under samples/application_development

Also, do not call it test_***, if it is a test, it should not be under samples/

nashif · 2018-12-04T06:11:14Z

scripts/gen_relocate_app.py

@@ -0,0 +1,370 @@
+#!/usr/bin/env python3


Please spend some time on this script and fix the syntax, you get it to a higher score, at least 8.00 :)

************* Module gen_relocate_app scripts/gen_relocate_app.py:12:0: C0301: Line too long (110/100) (line-too-long) scripts/gen_relocate_app.py:75:29: C0326: Exactly one space required before assignment extern_linker_var_declaration= """ ^ (bad-whitespace) scripts/gen_relocate_app.py:101:15: C0326: Exactly one space required before assignment memset_template= """ ^ (bad-whitespace) scripts/gen_relocate_app.py:108:26: C0326: No space allowed after bracket full_lib = ELFFile( f) ^ (bad-whitespace) scripts/gen_relocate_app.py:109:0: C0325: Unnecessary parens after 'if' keyword (superfluous-parens) scripts/gen_relocate_app.py:110:40: C0326: Exactly one space required after comma print("Error parsing file: ",filename) ^ (bad-whitespace) scripts/gen_relocate_app.py:113:19: C0326: No space allowed after bracket sections = [ x for x in full_lib.iter_sections()] ^ (bad-whitespace) scripts/gen_relocate_app.py:118:0: C0325: Unnecessary parens after 'if' keyword (superfluous-parens) scripts/gen_relocate_app.py:121:0: C0325: Unnecessary parens after 'if' keyword (superfluous-parens) scripts/gen_relocate_app.py:124:0: C0325: Unnecessary parens after 'if' keyword (superfluous-parens) scripts/gen_relocate_app.py:127:0: C0325: Unnecessary parens after 'if' keyword (superfluous-parens) scripts/gen_relocate_app.py:135:0: C0325: Unnecessary parens after 'if' keyword (superfluous-parens) scripts/gen_relocate_app.py:136:26: C0326: No space allowed after bracket symbols = [ x for x in section.iter_symbols()] ^ (bad-whitespace) scripts/gen_relocate_app.py:139:0: C0301: Line too long (120/100) (line-too-long) scripts/gen_relocate_app.py:150:49: C0326: Exactly one space required after comma memory_type = memory_type.replace("_TEXT","") ^ (bad-whitespace) scripts/gen_relocate_app.py:153:51: C0326: Exactly one space required after comma memory_type = memory_type.replace("_RODATA","") ^ (bad-whitespace) scripts/gen_relocate_app.py:156:49: C0326: Exactly one space required after comma memory_type = memory_type.replace("_DATA","") ^ (bad-whitespace) scripts/gen_relocate_app.py:159:48: C0326: Exactly one space required after comma memory_type = memory_type.replace("_BSS","") ^ (bad-whitespace) scripts/gen_relocate_app.py:167:0: C0330: Wrong continued indentation before block (add 4 spaces). full_list_of_sections[iter_sec] != []): ^ | (bad-continuation) scripts/gen_relocate_app.py:173:64: C0326: No space allowed before bracket tmp_list = {"text":[], "rodata":[], "data":[], "bss":[] } ^ (bad-whitespace) scripts/gen_relocate_app.py:176:0: C0330: Wrong continued indentation before block (add 4 spaces). full_list_of_sections[iter_sec] != []): ^ | (bad-continuation) scripts/gen_relocate_app.py:197:0: C0325: Unnecessary parens after 'if' keyword (superfluous-parens) scripts/gen_relocate_app.py:229:21: C0326: Exactly one space required after assignment generate_section ={"text":False, "rodata":False, "data":False, "bss":False } ^ (bad-whitespace) scripts/gen_relocate_app.py:229:79: C0326: No space allowed before bracket generate_section ={"text":False, "rodata":False, "data":False, "bss":False } ^ (bad-whitespace) scripts/gen_relocate_app.py:233:58: C0326: Exactly one space required after comma memory_type = memory_type.replace(section_name,"") ^ (bad-whitespace) scripts/gen_relocate_app.py:244:24: C0326: Exactly one space required after comma for mtype in ["text","rodata", "data"]: ^ (bad-whitespace) scripts/gen_relocate_app.py:263:0: W0301: Unnecessary semicolon (unnecessary-semicolon) scripts/gen_relocate_app.py:287:0: C0330: Wrong continued indentation (add 12 spaces). help="input src:memory type(sram2 or ccm or aon etc) string") ^ | (bad-continuation) scripts/gen_relocate_app.py:291:67: C0326: No space allowed before keyword argument assignment parser.add_argument("-v", "--verbose", action="count", default =0, ^ (bad-whitespace) scripts/gen_relocate_app.py:304:51: C0326: Exactly one space required after comma fullname = os.path.join(dirpath,filename1) ^ (bad-whitespace) scripts/gen_relocate_app.py:325:46: C0326: Exactly one space required after comma print("Memory region ", mem_region," Selected for file:", file_name_list) ^ (bad-whitespace) scripts/gen_relocate_app.py:331:0: C0325: Unnecessary parens after 'return' keyword (superfluous-parens) scripts/gen_relocate_app.py:346:20: C0326: Exactly one space required after comma for memory_type,files in rel_dict.items(): ^ (bad-whitespace) scripts/gen_relocate_app.py:347:30: C0326: Exactly one space required after assignment full_list_of_sections ={"text":[], "rodata":[], "data":[], "bss":[] } ^ (bad-whitespace) scripts/gen_relocate_app.py:347:76: C0326: No space allowed before bracket full_list_of_sections ={"text":[], "rodata":[], "data":[], "bss":[] } ^ (bad-whitespace) scripts/gen_relocate_app.py:1:0: C0111: Missing module docstring (missing-docstring) scripts/gen_relocate_app.py:37:0: C0103: Constant name "print_template" doesn't conform to UPPER_CASE naming style (invalid-name) scripts/gen_relocate_app.py:41:0: C0103: Constant name "group_start_end_memory_seq" doesn't conform to UPPER_CASE naming style (invalid-name) scripts/gen_relocate_app.py:45:0: C0103: Constant name "section_load_memory_seq" doesn't conform to UPPER_CASE naming style (invalid-name) scripts/gen_relocate_app.py:49:0: C0103: Constant name "load_address_location_flash" doesn't conform to UPPER_CASE naming style (invalid-name) scripts/gen_relocate_app.py:50:0: C0103: Constant name "load_address_location_bss" doesn't conform to UPPER_CASE naming style (invalid-name) scripts/gen_relocate_app.py:53:0: C0103: Constant name "linker_section_seq" doesn't conform to UPPER_CASE naming style (invalid-name) scripts/gen_relocate_app.py:68:0: C0103: Constant name "source_code_includes" doesn't conform to UPPER_CASE naming style (invalid-name) scripts/gen_relocate_app.py:75:0: C0103: Constant name "extern_linker_var_declaration" doesn't conform to UPPER_CASE naming style (invalid-name) scripts/gen_relocate_app.py:82:0: C0103: Constant name "data_copy_function" doesn't conform to UPPER_CASE naming style (invalid-name) scripts/gen_relocate_app.py:89:0: C0103: Constant name "bss_zeroing_function" doesn't conform to UPPER_CASE naming style (invalid-name) scripts/gen_relocate_app.py:96:0: C0103: Constant name "memcpy_template" doesn't conform to UPPER_CASE naming style (invalid-name) scripts/gen_relocate_app.py:101:0: C0103: Constant name "memset_template" doesn't conform to UPPER_CASE naming style (invalid-name) scripts/gen_relocate_app.py:106:0: C0111: Missing function docstring (missing-docstring) scripts/gen_relocate_app.py:107:33: C0103: Variable name "f" doesn't conform to snake_case naming style (invalid-name) scripts/gen_relocate_app.py:111:12: E1101: Module 'os' has no 'exit' member; maybe '_exit'? (no-member) scripts/gen_relocate_app.py:144:0: C0111: Missing function docstring (missing-docstring) scripts/gen_relocate_app.py:184:0: C0111: Missing function docstring (missing-docstring) scripts/gen_relocate_app.py:185:4: W0621: Redefining name 'string' from outer scope (line 29) (redefined-outer-name) scripts/gen_relocate_app.py:190:0: C0111: Missing function docstring (missing-docstring) scripts/gen_relocate_app.py:192:4: W0621: Redefining name 'string' from outer scope (line 29) (redefined-outer-name) scripts/gen_relocate_app.py:214:0: C0111: Missing function docstring (missing-docstring) scripts/gen_relocate_app.py:215:4: W0621: Redefining name 'string' from outer scope (line 29) (redefined-outer-name) scripts/gen_relocate_app.py:223:36: C0103: Variable name "fw" doesn't conform to snake_case naming style (invalid-name) scripts/gen_relocate_app.py:226:0: C0111: Missing function docstring (missing-docstring) scripts/gen_relocate_app.py:258:0: C0111: Missing function docstring (missing-docstring) scripts/gen_relocate_app.py:259:4: W0621: Redefining name 'string' from outer scope (line 29) (redefined-outer-name) scripts/gen_relocate_app.py:275:35: C0103: Variable name "fw" doesn't conform to snake_case naming style (invalid-name) scripts/gen_relocate_app.py:279:0: C0111: Missing function docstring (missing-docstring) scripts/gen_relocate_app.py:280:4: C0103: Constant name "args" doesn't conform to UPPER_CASE naming style (invalid-name) scripts/gen_relocate_app.py:280:4: W0601: Global variable 'args' undefined at the module level (global-variable-undefined) scripts/gen_relocate_app.py:296:0: C0111: Missing function docstring (missing-docstring) scripts/gen_relocate_app.py:296:0: R1710: Either all return statements in a function should return an expression, or none of them should. (inconsistent-return-statements) scripts/gen_relocate_app.py:300:17: W0612: Unused variable 'dirs' (unused-variable) scripts/gen_relocate_app.py:309:0: C0111: Missing function docstring (missing-docstring) scripts/gen_relocate_app.py:314:8: E1101: Module 'os' has no 'exit' member; maybe '_exit'? (no-member) scripts/gen_relocate_app.py:334:0: C0111: Missing function docstring (missing-docstring) scripts/gen_relocate_app.py:342:4: W0612: Unused variable 'raw' (unused-variable) scripts/gen_relocate_app.py:25:0: W0611: Unused import sys (unused-import) scripts/gen_relocate_app.py:28:0: W0611: Unused import re (unused-import) scripts/gen_relocate_app.py:29:0: W0611: Unused import string (unused-import) scripts/gen_relocate_app.py:31:0: C0411: standard import "import glob" should be placed before "from elftools.elf.elffile import ELFFile" (wrong-import-order) scripts/gen_relocate_app.py:32:0: C0411: standard import "import warnings" should be placed before "from elftools.elf.elffile import ELFFile" (wrong-import-order) ----------------------------------- Your code has been rated at 5.35/10

@nashif from where can I run this?

@nashif comments handled. please re-review.

This script will relocate .text .data and .bss sections from required files and places it in the required memory region. This memory region and file are given to this python script in the form of a string. Refer to the script for the format of this string and the procedure to invoke it. The main goal of this script is to provide a robust way to re-order the memory contents without actually having to modify the code (C source code and the linker code). In simple terms this script will do the job of __attribute__((section("name"))) for a bunch of files together. Signed-off-by: Varun Sharma <[email protected]> Signed-off-by: Adithya Baglody <[email protected]>

This patch creates a rule in the cmake to trigger the generation of linker_relocate.ld and code_relocation.c files. The linker_relocate.ld will create appropriate sections and will link the required functions or variables from all the selected files. The code_relocation.c will have code that is needed for initializing data sections and copy of text sections(if XIP). Also this will contain code that is needed for zeroing of bss. The procedure to invoke this feature is: 1. Enable CONFIG_CODE_RELOCATION in the prj.conf 2. Inside CMakeList.txt in the project we need to mention all the files that needs to get relocated. zephyr_kernel_code_relocate(src/*.c SRAM2) Where the first argument is the file/files and the second argument is the memory where it has be placed. NOTE: The file argument supports glob expressions. NOTE: Step 2 can be done as many times as required. And relative paths can be given here. Signed-off-by: Adithya Baglody <[email protected]>

This patch splits the text section into 2 parts. The first section will have some info regarding vector tables and debug info. The second section will have the complete text section. This is needed to force the required functions and data variables the correct locations. This is due to the behavior of the linker. The linker will only link once and hence this text section had to be split to make room for the generated linker script. Added a new Kconfig CODE_DATA_RELOCATION which when enabled will invoke the script, which does the required relocation. Added hooks inside init.c for bss zeroing and data copy operations. Needed when we have to copy data from ROM to required memory type. Signed-off-by: Adithya Baglody <[email protected]>

When code relocation feature with userspace mode is turned on we need a bit more memory to fit the text section for these 2 generated files. Signed-off-by: Adithya Baglody <[email protected]>

This sample provides an example for using the code relocation feature. This example will place text,data,bss from 3 files to various parts in the SRAM. For this a custom linker file is used which is derived from include/arch/arm/cortex_m/scripts/linker.ld. Signed-off-by: Varun Sharma <[email protected]> Signed-off-by: Adithya Baglody <[email protected]>

Added basic working details of code/data/bss relocation feature, how to use with examples & code sample details Signed-off-by: Varun Sharma <[email protected]>

This patch ensures that there are no .common variables in the test case. Signed-off-by: Adithya Baglody <[email protected]>

The header ipm_quark_se.h was creating a object. Hence removed it and placed the same in ipm_quark_se.c Signed-off-by: Adithya Baglody <[email protected]>

This header was creating an object instead of a typdef. Fixed the bug. Signed-off-by: Adithya Baglody <[email protected]>

This header was actually creating a struct in the bss. Fixed it. Signed-off-by: Adithya Baglody <[email protected]>

Instead of creating an typedef enum it was creating an object. Signed-off-by: Adithya Baglody <[email protected]>

These tests were creating objects from header file in the bss. Fixed it by moving the objects to appropriate object files. Signed-off-by: Adithya Baglody <[email protected]>

This sample was creating objects from header file in the bss. Fixed it by moving the objects to appropriate object files. Signed-off-by: Adithya Baglody <[email protected]>

This is needed to force the .common type to .bss type. This will force the .common variables to go into bss section in the compiled object file. As of now the movement to the .bss section was happening only during the final linking stage. The -fno-common option specifies that the compiler should place uninitialized global variables in the data section of the object file, rather than generating them as common blocks. This has the effect that if the same variable is declared (without "extern") in two different compilations, you will get a multiple-definition error when you link them. e.g: // file a.c // file-scope int b; // file b.c // file-scope int b; If there exist two non-extern declarations of the same variable then no-common will cause a linker error. This sequence would have compiled before, but will now cause a linker error. Signed-off-by: Adithya Baglody <[email protected]>

AdithyaBaglody · 2018-12-06T04:36:51Z

@nashif can we merge this now.

spoorthik · 2018-12-11T07:59:43Z

samples/application_development/code_relocation/linker_arm_sram2.ld

@@ -0,0 +1,42 @@
+/*
+ * Copyright (c) 2013-2014 Wind River Systems, Inc.
+ *


Shouldn't the copyright be updated? Same with few more files.

varun-sha requested review from andrewboie, andyross, nashif and SebastianBoe as code owners October 28, 2018 21:35

nashif self-assigned this Oct 28, 2018

varun-sha force-pushed the linker_relocate_script branch from 96a9c88 to 0edb095 Compare October 29, 2018 08:37

SebastianBoe previously requested changes Oct 29, 2018

View reviewed changes

varun-sha force-pushed the linker_relocate_script branch 2 times, most recently from ace1c8b to 71302cc Compare October 29, 2018 12:59

varun-sha requested a review from AdithyaBaglody October 29, 2018 13:10

varun-sha changed the title ~~Scripts: gen_relocate_app.py: to relocate code/data/bss sections~~ [RFC] Scripts: gen_relocate_app.py: to relocate code/data/bss sections Oct 31, 2018

varun-sha force-pushed the linker_relocate_script branch from 2c7dcb6 to 9c07de0 Compare October 31, 2018 11:34