[PATCH v3] elf: Set p_align to the minimum page size if possible

[H.J. Lu]

On Fri, Jan 14, 2022 at 12:27 AM Jan Beulich <jbeulich@suse.com> wrote:
>
> On 29.12.2021 20:39, H.J. Lu via Binutils wrote:
> > --- a/ld/testsuite/ld-elf/linux-x86.exp
> > +++ b/ld/testsuite/ld-elf/linux-x86.exp
> > @@ -185,6 +185,42 @@ run_ld_link_exec_tests [list \
> >       "" \
> >       "tmpdir/indirect-extern-access-2.so" \
> >      ] \
> > +    [list \
> > +     "Run p_align-1a without PIE" \
> > +     "$NOPIE_LDFLAGS" \
> > +     "" \
> > +     { p_align-1.c } \
> > +     "p_align-1a" \
> > +     "pass.out" \
> > +     "$NOPIE_CFLAGS" \
> > +    ] \
> > +    [list \
> > +     "Run p_align-1b with PIE" \
> > +     "-pie" \
> > +     "" \
> > +     { p_align-1.c } \
> > +     "p_align-1b" \
> > +     "pass.out" \
> > +     "-fpie" \
> > +    ] \
> > +    [list \
> > +     "Run p_align-1c with -Wl,-z,max-page-size=0x1000 without PIE" \
> > +     "$NOPIE_LDFLAGS -Wl,-z,max-page-size=0x1000" \
> > +     "" \
> > +     { p_align-1.c } \
> > +     "p_align-1c" \
> > +     "pass.out" \
> > +     "$NOPIE_CFLAGS" \
> > +    ] \
> > +    [list \
> > +     "Run p_align-1d with -Wl,-z,max-page-size=0x1000 with PIE" \
> > +     "-pie -Wl,-z,max-page-size=0x1000" \
> > +     "" \
> > +     { p_align-1.c } \
> > +     "p_align-1d" \
> > +     "pass.out" \
> > +     "-fpie" \
> > +    ] \
> >  ]
>
> The two PIE variants of this also fail for me on glibc 2.26. Looks
> like LOAD segments' alignment isn't being honored there, at least
> not if it's as big as it is here.
>

The PIE alignment needs the kernel fix:

commit ce81bb256a224259ab686742a6284930cbe4f1fa
Author: Chris Kennelly <ckennelly@google.com>
Date:   Thu Oct 15 20:12:32 2020 -0700

    fs/binfmt_elf: use PT_LOAD p_align values for suitable start address


-- 
H.J.