Re: [edk2-devel] [PATCH v1 1/1] BaseTools: Build ASL files before C files

["Ard Biesheuvel" <ard.biesheuvel@linaro.org>]

(+ Leif)

On Thu, 19 Dec 2019 at 13:19, Pierre Gondois <Pierre.Gondois@arm.com> wrote:
>
> Hello Ard,
> I cannot find any documentation more than what the iASL compiler does with the '-tc' argument:
>  -tc                 Create hex AML table in C (*.hex)
>
> The '.hex' file looks like this:
>
> #ifndef __ASL_SOURCE_FILE_HEX__
> #define __ASL_SOURCE_FILE_HEX__
>
> unsigned char ASL_SOURCE_FILE[] =
> {
>     0x53,0x53,0x44,0x54,0xAD,0x00,0x00,0x00,  /* 00000000    "SSDT...." */
>     0x01,0xF8,0x41,0x52,0x4D,0x4C,0x54,0x44,  /* 00000008    "..ARMLTD" */
> ...
> }
>
> #endif __ASL_SOURCE_FILE_HEX__
>
> I can make a python script to create a similar '.hex' file in case the iASL compiler changes its ouput. However this script would have to be included in Conf/build_rule.txt.
>

I understand the appeal of using intermediate output of the iasl
compiler, but I don't think we should rely on this unless it is a
clear stable interface. Managing the complexity of all the various
toolchains and build tools is already proving to be too difficult, and
adding another degree of freedom is not a good idea.

Can you explain why exactly you need this?



> -----Original Message-----
> From: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> Sent: 18 December 2019 17:50
> To: edk2-devel-groups-io <devel@edk2.groups.io>; Pierre Gondois <Pierre.Gondois@arm.com>
> Cc: Feng, Bob C <bob.c.feng@intel.com>; Gao, Liming <liming.gao@intel.com>; Sami Mujawar <Sami.Mujawar@arm.com>; nd <nd@arm.com>
> Subject: Re: [edk2-devel] [PATCH v1 1/1] BaseTools: Build ASL files before C files
>
> On Wed, 30 Oct 2019 at 15:50, PierreGondois <pierre.gondois@arm.com> wrote:
> >
> > From: Pierre Gondois <pierre.gondois@arm.com>
> >
> > The '-tc' option of the Intel iASL compiler facilitates generation of
> > AML code in a C array. This AML code is output to a .hex file. The
> > .hex file can be included from a C source file, thereby allowing one
> > to run a fix-up code in C.
> >
> > For example, this technique can be used to patch the resource data
> > elements that describe the base address or interrupt number for a
> > device, before installing the ACPI table.
> >
> > To implement this feature two conditions need to be
> > satisfied:
> >  - The ASL and C files must be included in the sources
> >    section of the same .inf file for the module.
> >  - The ASL files are pre-processed and compiled before
> >    the C files (so that the .hex file include dependency
> >    is satisfied).
> >
> > This patch resolves the dependency by sorting the CODA_TARGET list for
> > the module being built and placing the .aml files at the very
> > beginning of the list.
> >
> > Signed-off-by: Pierre Gondois <pierre.gondois@arm.com>
> > ---
> >
> > The changes can be seen at
> > https://github.com/PierreARM/edk2/commits/676_build_asl_first_v1
> >
>
> Hello Pierre,
>
> I am not convinced it is a good idea to depend on what amounts to an implementation detail of the ASL compiler. Is the .hex format documented somewhere?
>
>
> > Notes:
> >     v1:
> >     - Sort .aml files first in the CODA_TARGET to build      [Pierre]
> >       them before other files.
> >
> >  BaseTools/Source/Python/AutoGen/ModuleAutoGen.py | 10 +++++++++-
> >  1 file changed, 9 insertions(+), 1 deletion(-)
> >
> > diff --git a/BaseTools/Source/Python/AutoGen/ModuleAutoGen.py
> > b/BaseTools/Source/Python/AutoGen/ModuleAutoGen.py
> > index
> > f0812b6887be6f9fbdb14003f2efff229633fb34..a59ed1d1952c23d0d3de83353a05
> > 66fb8a7dab77 100755
> > --- a/BaseTools/Source/Python/AutoGen/ModuleAutoGen.py
> > +++ b/BaseTools/Source/Python/AutoGen/ModuleAutoGen.py
> > @@ -2,6 +2,7 @@
> >  # Create makefile for MS nmake and GNU make  #  # Copyright (c) 2019,
> > Intel Corporation. All rights reserved.<BR>
> > +# Copyright (c) 2019, ARM Limited. All rights reserved.<BR>
> >  # SPDX-License-Identifier: BSD-2-Clause-Patent  #  from __future__
> > import absolute_import @@ -931,7 +932,14 @@ class
> > ModuleAutoGen(AutoGen):
> >      @cached_property
> >      def CodaTargetList(self):
> >          self.Targets
> > -        return self._FinalBuildTargetList
> > +
> > +        # To resolve dependencies on compiled ASL files (.aml files) in modules,
> > +        # build them first by putting them as the first targets in the
> > +        # CodaTargetList.
> > +        OrderedList = list(self._FinalBuildTargetList)
> > +        OrderedList.sort(key=lambda T: (T.Target.Ext.lower() !=
> > + '.aml'))
> > +
> > +        return OrderedList
> >
> >      @cached_property
> >      def FileTypes(self):
> > --
> > 'Guid(CE165669-3EF3-493F-B85D-6190EE5B9759)'
> >
> >
> >
> > 
> >