Subject: Re: [PATCH 2.6.14] mm: 8xx MM fix for

From: Benjamin Herrenschmidt <[email-masked]>
Date: Mon, 31 Oct 2005 08:16:04 +1100

On Sun, 2005-10-30 at 23:03 +0300, Pantelis Antoniou wrote:
> Latest MMU changes caused 8xx to stop working. Flushing tlb of the faulting
> address fixes the problem.

Ugh ?

What is the problem precisely ? This is just a dodgy workaround for an
unexplained problem. Normally, the kenrel _WILL_ cause a tlb flush after
manipulating a PTE.

Ben.

> ---
> commit 978e2f36b1ae53e37ba27b3ab8f1c5ddbb8c8a10
> tree 7dd0e403c240162b1925db0834d694f4b4a0e95e
> parent ca02ea5aebcda886d1552c6af73ca96c02bf9fed
> author Pantelis Antoniou <panto@pantathon> Sun, 30 Oct 2005 21:53:48 +0200
> committer Pantelis Antoniou <panto@pantathon> Sun, 30 Oct 2005 21:53:48 +0200
> 
>  arch/ppc/mm/fault.c |   13 +++++++++++++
>  1 files changed, 13 insertions(+), 0 deletions(-)
> 
> diff --git a/arch/ppc/mm/fault.c b/arch/ppc/mm/fault.c
> --- a/arch/ppc/mm/fault.c
> +++ b/arch/ppc/mm/fault.c
> @@ -240,6 +240,19 @@ good_area:
>  			goto bad_area;
>  		if (!(vma->vm_flags & (VM_READ | VM_EXEC)))
>  			goto bad_area;
> +
> +#ifdef CONFIG_8xx
> +		{
> +		/* 8xx is retarded; news at 11 */
> +		pte_t *ptep = NULL;
> +
> +		if (get_pteptr(mm, address, &ptep) && pte_present(*ptep))
> +			_tlbie(address);
> +
> +		if (ptep != NULL)
> +			pte_unmap(ptep);
> +		}
> +#endif
>  	}
>  
>  	/*