audk/BaseTools
Jake Garver 5d533bbc27 BaseTools/GenFw: Correct offset when relocating an ADR
When converting ELF to PE/COFF for the AArch64 target, we may encounter
an R_AARCH64_ADR_GOT_PAGE relocation that refers to an ADR instruction
instead of an ADRP instruction. This can happen when the toolchain is
working around Cortex-A53 erratum #843419.  If that's the case, be sure
to calculate the offset appropriately.

This resolves an issue experienced when building a StandaloneMm image
(which is built with -fpie) with stack protection enabled on GCC
compiled with "--enable-fix-cortex-a53-843419". In this case, the linker
may convert an ADRP instruction appearing at an offset of 0xff8 or 0xffc
modulo 4KiB into an ADR instruction, but will leave the original
R_AARCH64_ADR_GOT_PAGE relocation in place. (This is not a bug in the
linker, given that there is no other relocation type that it could
reasonably convert it into)

In this scenario, the following code is being generated by the
toolchain:

    # Load to set the stack canary
    2ffc:	10028020 	adr	x0, 8000 <mErrorString+0x1bc>
    3008:	f940d400 	ldr	x0, [x0, #424]

    # Load to check the stack canary
    30cc:	b0000020 	adrp	x0, 8000 <mErrorString+0x1bc>
    30d0:	f940d400 	ldr	x0, [x0, #424]

GenFw rewrote that to:

    # Load to set the stack canary
    2ffc:	10000480 	adr	x0, 0x308c
    3008:	912ec000 	add	x0, x0, #0xbb0

    # Load to check the stack canary
    30cc:	f0000460 	adrp	x0, 0x92000
    30d0:	912ec000 	add	x0, x0, #0xbb0

Note that we're now setting the stack canary from the wrong address,
resulting in an erroneous stack fault.

After this fix, the offset will be calculated correctly for an ADR and
the stack canary is set correctly. Note that there is a corner case
where this may cause the conversion to fail: if the original GOT entry
is just within -/+ 1 MiB of the reference, but the actual variable it
refers to is not, the resulting offset cannot be represented by the
immediate offset field in a ADR instruction. Given that this issue only
affects PIE executables, which are rare and usually tiny, this is
unlikely to cause problems in practice.

Ref: https://edk2.groups.io/g/devel/topic/102202314

[ardb: expand commit log, add reference]

Signed-off-by: Jake Garver <jake@nvidia.com>
Reviewed-by: Rebecca Cran <rebecca@bsdio.com>
2023-12-21 10:08:47 +00:00
..
Bin BaseTools: Delete Bin/{CYGWIN_NT-5.1-i686,Darwin-i386} directories 2023-01-30 16:50:14 +00:00
BinPipWrappers BaseTools: Fix BrotliCompress run issue on Linux 2021-02-22 09:51:17 +00:00
BinWrappers BaseTools: Add FMMT Python Tool 2022-05-06 04:22:21 +00:00
Conf BaseTools/Conf/target.template: Use VS2019 as default tool chain 2023-11-29 20:44:12 +00:00
Plugin BaseTools/Plugin/CodeQL: Enable 30 queries 2023-11-07 03:19:26 +00:00
Scripts BaseTools/Scripts/GetMaintainer: Sort output addresses 2023-11-11 02:31:13 +00:00
Source BaseTools/GenFw: Correct offset when relocating an ADR 2023-12-21 10:08:47 +00:00
Tests BaseTools: Update Tests/TestTools.py to allow it to work on Windows 2023-05-11 02:14:12 +00:00
UserManuals BaseTools: GenFw: auto-set nxcompat flag 2023-11-06 21:44:34 +00:00
.gitignore .gitignore: Ignore build tools build logs 2022-07-09 14:57:49 +00:00
BuildEnv Remove bashisms from edksetup.sh and BaseTools/BuildEnv 2023-05-10 12:02:34 +00:00
Edk2ToolsBuild.py BaseTools: scan Edk2ToolsBuild.py make output 2023-08-02 15:20:47 +00:00
GNUmakefile BaseTools: Replace BSD License with BSD+Patent License 2019-04-09 09:10:20 -07:00
Makefile BaseTools: Replace BSD License with BSD+Patent License 2019-04-09 09:10:20 -07:00
ReadMe.rst BaseTools: Add reference to new build instructions 2022-12-16 22:17:18 +00:00
basetools_calling_path_env.yaml BaseTools: Add YAML files with path env and tool extdeps 2019-11-11 13:01:53 -08:00
basetools_path_env.yaml BaseTools: Add YAML files with path env and tool extdeps 2019-11-11 13:01:53 -08:00
get_vsvars.bat BaseTools: Remove VS2008-VS2013 remnants 2023-05-05 11:41:35 +00:00
set_vsprefix_envs.bat BaseTools: Remove VS2008-VS2013 remnants 2023-05-05 11:41:35 +00:00
toolsetup.bat BaseTools: toolsetup.bat always execute PYTHON_HOME 2023-05-29 01:34:28 +00:00

ReadMe.rst

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::

  Note: New build instructions are available. It is recommended to start with
  the new instructions if learning how to build edk2 and/or BaseTools for the
  first time. This page is retained for reference.

New instructions: `Build Instructions`_

.. _`Build Instructions`: https://github.com/tianocore/tianocore.github.io/wiki/Build-Instructions

This directory contains the EDK II build tools and template files.
Templates are located in the Conf directory, while the tools executables for
Microsoft Windows Operating Systems are located in the Bin\\Win32 directory, other
directory contains tools source.

Build step to generate the binary tools
---------------------------------------

Windows/Visual Studio Notes
===========================

To build the BaseTools, you should run the standard vsvars32.bat script
from your preferred Visual Studio installation or you can run get_vsvars.bat
to use latest automatically detected version.

In addition to this, you should set the following environment variables::

 * EDK_TOOLS_PATH - Path to the BaseTools sub directory under the edk2 tree
 * BASE_TOOLS_PATH - The directory where the BaseTools source is located.
   (It is the same directory where this README.rst is located.)

After this, you can run the toolsetup.bat file, which is in the same
directory as this file.  It should setup the remainder of the environment,
and build the tools if necessary.

Unix-like operating systems
===========================

To build on Unix-like operating systems, you only need to type ``make`` in
the base directory of the project.

Ubuntu Notes
============

On Ubuntu, the following command should install all the necessary build
packages to build all the C BaseTools::

 sudo apt install build-essential uuid-dev