Re: [Xen-devel] [PATCH v3 1/9] xen: add a generic way to include binary files as variables

[Jan Beulich <jbeulich@xxxxxxxx>]

On 03.02.2020 15:02, Jürgen Groß wrote:
> On 03.02.20 14:39, Jan Beulich wrote:
>> On 21.01.2020 09:43, Juergen Gross wrote:
>>> --- /dev/null
>>> +++ b/xen/tools/binfile
>>> @@ -0,0 +1,29 @@
>>> +#!/bin/sh
>>> +# usage: binfile [-i] <target-src.S> <binary-file> <varname>
>>> +# -i     add to .init.rodata (default: .rodata) section
>>> +
>>> +[ "$1" = "-i" ] && {
>>> +    shift
>>> +    section=".init"
>>> +}
>>> +
>>> +target=$1
>>> +binsource=$2
>>> +varname=$3
>>> +
>>> +cat <<EOF >$target
>>> +#include <asm/asm_defns.h>
>>> +
>>> +        .section $section.rodata, "a", %progbits
>>> +
>>> +        .global $varname
>>> +$varname:
>>> +        .incbin "$binsource"
>>> +.Lend:
>>> +
>>> +        .type $varname, %object
>>> +        .size $varname, . - $varname
>>
>> I'd prefer if you used .Lend here as well.
> 
> Okay.
> 
>> I wonder whether, right from the beginning, there wouldn't better
>> be a way to also request better than byte alignment for such a
>> blob.
> 
> I can add that. What about "-a <n>" for 2^n alignment?

SGTM.

>>> --- a/xen/xsm/flask/Makefile
>>> +++ b/xen/xsm/flask/Makefile
>>> @@ -30,6 +30,9 @@ $(AV_H_FILES): $(AV_H_DEPEND)
>>>   obj-bin-$(CONFIG_XSM_FLASK_POLICY) += flask-policy.o
>>>   flask-policy.o: policy.bin
>>>   
>>> +flask-policy.S: $(XEN_ROOT)/xen/tools/binfile
>>> +   $(XEN_ROOT)/xen/tools/binfile -i $@ policy.bin xsm_flask_init_policy
>>
>> Doesn't objcopy provide a means to convert a binary blob into
>> an ELF object containing the binary data from the input file?
>> If so, why involve the assembler and an intermediate file here?
> 
> I can see how to add a symbol for that purpose using a dedicated section
> for each blob, but how to add the size information of the blob?

Hmm, right. It would be doable, but perhaps indeed not very nice.
Fair enough then.

Jan

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