Re: [PATCH v1] xen/arm: align *(.proc.info) in the linker script

[Julien Grall <julien@xxxxxxx>]

Hi Jan,

On 02/03/2023 11:21, Jan Beulich wrote:
> On 02.03.2023 12:01, Julien Grall wrote:
> > On 02/03/2023 09:45, Jan Beulich wrote:
> > > On 01.03.2023 21:38, Julien Grall wrote:
> > > > I managed to reproduce it. It looks like that after your bug patch,
> > > > *(.rodata.*) will not be end on a 4-byte boundary. Before your patch,
> > > > all the messages will be in .rodata.str. Now they are in .bug_frames.*,
> > > > so there some difference in .rodata.*.
> > > Strings in .bug_frames.*? This sounds like a mistake, which - if indeed
> > > the case - will want investigating before the conversion series is
> > > actually considered for committing.
> > No. I misread the code. But there are definitely a difference in size:
> >
> > Before:
> >
> > Section Headers:
> >     [Nr] Name              Type            Addr     Off    Size   ES Flg
> > Lk Inf Al
> >     [ 0]                   NULL            00000000 000000 000000 00
> > 0   0  0
> >     [ 1] .text             PROGBITS        00200000 008000 07e7a8 00 WAX
> > 0   0 32
> >     [ 2] .rodata           PROGBITS        0027f000 087000 02acc8 00   A
> > 0   0 16
> > [...]
> > After:
> >
> >     [Nr] Name              Type            Addr     Off    Size   ES Flg
> > Lk Inf Al
> >     [ 0]                   NULL            00000000 000000 000000 00
> > 0   0  0
> >     [ 1] .text             PROGBITS        00200000 008000 07e670 00 WAX
> > 0   0 32
> >     [ 2] .rodata           PROGBITS        0027f000 087000 02b3e8 00   A
> > 0   0 16
> I still find this concerning (as in: at least needing explanation), as
> the bug frame representation shrinks in size: Entries for assertions
> remain to be 4 ".long"-s, while all other entries use only two now. So
> in a release build the size of all .bug_frame.* together should halve,
> while in debug builds it should shrink at least some. And Oleksii's
> series doesn't add meaningful other contributions to .rodata, iirc.
Doh, I inverted the two tables. So .rodata is shrinking but .txt is 
slightly increasing.
Cheers,

--
Julien Grall