Re: [uClinux-dev] Re: [PATCH] FDPIC: respect PT_GNU_STACK exec markings when creating NOMMU stack

From: Mike Frysinger
Date: Fri Dec 04 2009 - 02:02:07 EST


On Thursday 03 December 2009 12:58:04 David Howells wrote:
> Mike Frysinger <vapier.adi@xxxxxxxxx> wrote:
> > i have seen a few apps use brk()/sbrk() to query the size of things (like
> > e2fsprogs)
>
> We do actually record the size of the brk segment, so maybe we could icache
> flush brk as it is increased (if it is increased):
>
> diff --git a/mm/nommu.c b/mm/nommu.c
> index 3754b16..2ea823d 100644
> --- a/mm/nommu.c
> +++ b/mm/nommu.c
> @@ -432,6 +432,7 @@ SYSCALL_DEFINE1(brk, unsigned long, brk)
> /*
> * Ok, looks good - let it rip.
> */
> + flush_icache_range(mm->brk, brk);
> return mm->brk = brk;
> }

probably want mm->brk + brk for the second argument
-mike

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