Re: [GIT PULL] s390 updates for 2.6.28-rc1

[Martin Schwidefsky <schwidefsky@de.ibm.com>]

On Fri, 2008-10-24 at 13:37 +0200, Ingo Molnar wrote:
> * Heiko Carstens <heiko.carstens@de.ibm.com> wrote:
> 
> > The s390 vdso preparation patch "arch_setup_additional_pages argument" 
> > touches other architectures (x86, sh and powerpc):
> > 
> > arch_setup_additional_pages currently gets two arguments, the binary 
> > format descripton and an indication if the process uses an executable 
> > stack or not. The second argument is not used by anybody, it could be 
> > removed without replacement.
> 
> hm, this is the first time i've seen this change,

The code is relatively new and I planned it for the merge window for
2.6.29. I still have to nag our performance team to do some tests with
it.

> and it looks a bit weird:
> 
> --- a/arch/x86/include/asm/elf.h
> +++ b/arch/x86/include/asm/elf.h
> @@ -325,7 +325,7 @@ struct linux_binprm;
> 
>  #define ARCH_HAS_SETUP_ADDITIONAL_PAGES 1
>  extern int arch_setup_additional_pages(struct linux_binprm *bprm,
> -                                      int executable_stack);
> +                                      int uses_interp);
> 
> why didnt you just add a new uses_interp argument?

I could have but I noticed at the same time that executable_stack is
unused. If somebody finds a need for the executable_stack argument it
can easily re-added but I can't think of a use for it. Ergo I removed
it.

> executable_stack is passed in to potentially enable architectures to be 
> aware of how conservative/legacy the address-space of the binary is - 
> whether to randomize the vdso, etc. exec-shield used to take advantage 
> of that.

What has address space layout / randomization to do with
executable_stack? You lost me there.

> But there seems to be no in-tree use of that (and if one arises it can 
> just add back that parameter), and i dont want to stand in the way of 
> your pull request either, so for the x86 bits:
> 
>  Acked-by: Ingo Molnar <mingo@elte.hu>

Thanks. I'll add it.

-- 
blue skies,
  Martin.

"Reality continues to ruin my life." - Calvin.