Re: [PATCH][BZ #21779] Resolve non-relocatable branch in MicroBlaze pt-vfork.S

[Adhemerval Zanella <adhemerval dot zanella at linaro dot org>]

On 17/07/2017 09:58, Nathan Rossi wrote:
> The relative branch directly to __libc_vfork results in an relocation
> that cannot be resolved. Specifically a R_MICROBLAZE_64_PCREL relocation
> is created for this branch, however for MicroBlaze R_MICROBLAZE_64_PCREL
> type relocations symbols are not resolved. Additionally due to the
> branch being located in the .text section the instruction cannot be
> rewritten as the section is not writable, and causes a segfault at
> runtime when loading libpthread.
> 
> To resolve this issue, ensure the branch is done using PLT. This removes
> the need to modify the instruction and trades the R_MICROBLAZE_64_PCREL
> for a more common R_MICROBLAZE_JUMP via the PLT.
> 
> 2017-07-17  Nathan Rossi  <nathan@nathanrossi.com>
> 
>         [BZ #21779]
>         * sysdeps/unix/sysv/linux/microblaze/pt-vfork.S: Branch using PLT

LGTM, cross make clean shows no regression.  Since you seem to have access
to a microblaze ystem, it would be useful if you have time to run the
complete make check so we can update the 2.26 release wike [1].

[1] https://sourceware.org/glibc/wiki/Release/2.26

> ---
>  sysdeps/unix/sysv/linux/microblaze/pt-vfork.S | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/sysdeps/unix/sysv/linux/microblaze/pt-vfork.S b/sysdeps/unix/sysv/linux/microblaze/pt-vfork.S
> index f201f0429f..d8339f21f7 100644
> --- a/sysdeps/unix/sysv/linux/microblaze/pt-vfork.S
> +++ b/sysdeps/unix/sysv/linux/microblaze/pt-vfork.S
> @@ -34,7 +34,7 @@
>         || SHLIB_COMPAT (libpthread, GLIBC_2_1_2, GLIBC_2_20))
>  
>  ENTRY (vfork_compat)
> -	bri	__libc_vfork
> +	bri	__libc_vfork@PLT
>  END (vfork_compat)
>  
>  #endif
>