[PATCH 2/2] x86-64: Use MAXPAGESIZE for the relro segment alignment

[Michael Matz]

Hello,

On Tue, 15 Feb 2022, H.J. Lu wrote:

> > > Adjust x86-64 linker tests after reverting
> > >
> > > commit 31b4d3a16f200bf04db8439a63b72bba7af4e1be
> > > Author: Alan Modra <amodra@gmail.com>
> > > Date:   Thu Feb 3 08:57:47 2022 +1030
> > >
> > >     PR28824, relro security issues, x86 keep COMMONPAGESIZE relro
> > >
> > > to use MAXPAGESIZE for the end of the relro segment alignment, like other
> > > ELF targets.
> > >
> > > --- a/ld/testsuite/ld-x86-64/pr14207.d
> > > +++ b/ld/testsuite/ld-x86-64/pr14207.d
> > > @@ -11,9 +11,9 @@ There are 4 program headers, starting at offset 64
> > >  Program Headers:
> > >    Type           Offset   VirtAddr           PhysAddr           FileSiz  MemSiz   Flg Align
> > >    LOAD           0x000000 0x0000000000000000 0x0000000000000000 0x000150 0x000150 R   0x200000
> > > -  LOAD           0x000b.8 0x0000000000200b.8 0x0000000000200b.8 0x0004.0 0x000c.8 RW  0x200000
> > > -  DYNAMIC        0x000b.0 0x0000000000200b.0 0x0000000000200b.0 0x0001.0 0x0001.0 RW  0x8
> > > -  GNU_RELRO      0x000b.8 0x0000000000200b.8 0x0000000000200b.8 0x0004.0 0x0004.8 R   0x1
> > > +  LOAD           0x1ffb.8 0x00000000003ffb.8 0x00000000003ffb.8 0x0004.0 0x000c.8 RW  0x200000
> > > +  DYNAMIC        0x1ffb.0 0x00000000003ffb.0 0x00000000003ffb.0 0x0001.0 0x0001.0 RW  0x8
> > > +  GNU_RELRO      0x1ffb.8 0x00000000003ffb.8 0x00000000003ffb.8 0x0004.0 0x0004.8 R   0x1
> >
> > This change implies that the filesize increased by 2MB (and I verified
> > this to be the case).  I don't think that's a good trade-off.  E.g. I have
> > about 3500 binaries in /usr/bin/ alone.  That linker change translates to
> > an overall increase of 7 Gigabytes filesize.  Right now all the files
> > therein are about 1GB.
> >
> > So, please!
> 
> Do they use 2MB pages?

I missed the explicit '-z max-page-size=0x200000' in those tests link 
command and verified that not using it still generates small executables.
Sorry for the noise, by default everything should be just fine.


Ciao,
Michael.