[SeaBIOS] Compiling SeaBIOS for coreboot has problems with its ACPI code

[Gleb Natapov]

On Tue, Aug 07, 2012 at 07:34:37PM +0000, Moore, Robert wrote:
> This is very interesting. If I understand correctly, you are using a utility plus various directives to generate tables of AML offsets -- presumably in order to dynamically change AML values, correct?
> 
Yes.

> I have to say that I have not seen anything like this, from any BIOS vendor.
> 
Physical HW is not as dynamic (if at all) as virtualized one. We do not
want to have separate AML table for each possible HW configuration user
can create while starting QEMU.

> > By the way, is there interest in adding some of the functionality that
> > we get by parsing the listing to iasl directly?
> 
> We are always interested in adding features to make the compiler more useful. What would you suggest?
> 
The tool depends on the compiler output and thus fragile. It broke with new
compiler version. It would be nice if compiler had a way to generate
offsets for us.

> Bob
> 
> 
> > -----Original Message-----
> > From: Michael S. Tsirkin [mailto:mst at redhat.com]
> > Sent: Sunday, August 05, 2012 1:45 PM
> > To: Moore, Robert
> > Cc: Idwer Vollering; Kevin O'Connor; seabios at seabios.org; Tang, Feng
> > Subject: Re: [SeaBIOS] Compiling SeaBIOS for coreboot has problems with
> > its ACPI code
> > 
> > On Sun, Aug 05, 2012 at 11:36:15PM +0300, Michael S. Tsirkin wrote:
> > > On Mon, Jul 30, 2012 at 07:42:48PM +0000, Moore, Robert wrote:
> > > > Yes, you are correct, the listing no longer includes the comments.
> > > >
> > > > Sorry for causing you a problem.
> > > >
> > > > What is happening is that the preprocessor parser is stripping the
> > comments during the creation of the .i file. Then, the compiler is
> > invoked on the .i file -- thus, the comments are gone.
> > > >
> > > > This is going to take a bit of work to correct, but we will do it.
> > > >
> > > > In the meantime, try using the -Pn flag to disable the
> > preprocessor. When this flag is set, the  preprocessor is completely
> > bypassed and the compiler should function as it did previously.
> > >
> > >
> > > So we are doing it this way meanwhile.  If you change this
> > > preprocessor behaviour like you indicated you would, please let us
> > > know so e can test.
> > >
> > > Thanks!
> > 
> > By the way, is there interest in adding some of the functionality that
> > we get by parsing the listing to iasl directly?
> > Here's what our tool currently supports:
> > 
> > # Process mixed ASL/AML listing (.lst file) produced by iasl -l #
> > Locate and execute ACPI_EXTRACT directives, output offset info # #
> > Documentation of ACPI_EXTRACT_* directive tags:
> > #
> > # These directive tags output offset information from AML for BIOS
> > runtime # table generation.
> > # Each directive is of the form:
> > # ACPI_EXTRACT_<TYPE> <array_name> <Operator> (...) # and causes the
> > extractor to create an array # named <array_name> with offset, in the
> > generated AML, # of an object of a given type in the following
> > <Operator>.
> > #
> > # A directive must fit on a single code line.
> > #
> > # Object type in AML is verified, a mismatch causes a build failure.
> > #
> > # Directives and operators currently supported are:
> > # ACPI_EXTRACT_NAME_DWORD_CONST - extract a Dword Const object from
> > Name() # ACPI_EXTRACT_NAME_WORD_CONST - extract a Word Const object
> > from Name() # ACPI_EXTRACT_NAME_BYTE_CONST - extract a Byte Const
> > object from Name() # ACPI_EXTRACT_METHOD_STRING - extract a NameString
> > from Method() # ACPI_EXTRACT_NAME_STRING - extract a NameString from
> > Name() # ACPI_EXTRACT_PROCESSOR_START - start of Processor() block #
> > ACPI_EXTRACT_PROCESSOR_STRING - extract a NameString from Processor() #
> > ACPI_EXTRACT_PROCESSOR_END - offset at last byte of Processor() + 1 #
> > ACPI_EXTRACT_PKG_START - start of Package block # #
> > ACPI_EXTRACT_ALL_CODE - create an array storing the generated AML
> > bytecode # # ACPI_EXTRACT is not allowed anywhere else in code, except
> > in comments.
> > 
> > 
> > Example:
> > 
> >            ACPI_EXTRACT_NAME_DWORD_CONST aml_adr_dword
> >            Name (_ADR, 0x00010000)
> > 
> > adds the offset of 0x00010000 constant to array aml_adr_dword
> > 
> > Example:
> > 
> >           ACPI_EXTRACT_METHOD_STRING aml_ej0_name
> >           Method (_EJ0, 1) { Return(PCEJ(0x0001)) }
> > 
> > adds the offset of _EJ0 string to array aml_ej0_name
> > 
> > ACPI_EXTRACT_ALL_CODE ssdp_pcihp_aml
> > 
> > names the array to include the generated AML code
> > 
> > --
> > MST
> 
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--
			Gleb.