Re: [RFC] Add FR-V Linux core file support

[Daniel Jacobowitz <drow at false dot org>]

On Tue, Feb 14, 2006 at 02:10:16PM -0700, Kevin Buettner wrote:
> The patch below adds core file support for FR-V running either
> GNU/Linux or uClinux.
> 
> The interesting part of this patch is the bit which causes the main
> executable to get relocated.  I thought at first that I would need to
> add a new hook which does for core files what SOLIB_CREATE_INFERIOR_HOOK
> does for processes, but this turned out to not be necessary.  I was able
> to handle the case that I care about by adding a suitable call to
> frv_current_sos().  I was surprised, however, that we had (apparently)
> never run into this problem before.
> 
> Comments?

Hmm, interesting.  Two things poke out at me:

> +/* Technically, the loadmap addresses are not part of `pr_reg' as
> +   found in the elf_prstatus struct.  The fields which communicate the
> +   loadmap address appear (by design) immediately after `pr_reg'
> +   though, and the BFD function elf32_frv_grok_prstatus() has been
> +   implemented to include these fields in the register section that it
> +   extracts from the core file.  So, for our purposes, they may be
> +   viewed as registers.  */
> +
> +#define FRV_PT_EXEC_FDPIC_LOADMAP 46
> +#define FRV_PT_INTERP_FDPIC_LOADMAP 47

I assume that there can be threading on this target.  That means the
regset functions could be used for libthread_db too; are there going to
be loadmaps there too?

I don't much like faking registers this way, but the FRV port has prior
art - this isn't new - so I won't complain too much.  I'd have made
them a separate target object.

> @@ -421,6 +421,14 @@ frv_current_sos (void)
>    struct so_list *sos_head = NULL;
>    struct so_list **sos_next_ptr = &sos_head;
>  
> +  /* Make sure that the main executable has been relocated.  Normally
> +     this is done by SOLIB_CREATE_INFERIOR_HOOK(), however, this hook
> +     is not run when loading core files.  Rather than create a new hook,
> +     we'll do it here if necessary.  */
> +  if (main_executable_lm_info == 0 && core_bfd != NULL)
> +    frv_relocate_main_executable ();
> +
> +  /* Fetch the GOT corresponding to the main executable.  */
>    mgot = main_got ();
>  
>    /* Locate the address of the first link map struct.  */

Was this patch written recently, or forward ported from something a
bit older?  I'm thinking 2006-01-24 here.  The new post_create_inferior
is called when loading core files, and in turn calls
solib_create_inferior_hook.

-- 
Daniel Jacobowitz
CodeSourcery