From: David Gibson <david@gibson.dropbear.id.au>
To: Russell King <rmk@arm.linux.org.uk>
Cc: Andrew Morton <akpm@digeo.com>, David Miller <davem@redhat.com>,
Paul Mackerras <paulus@samba.org>,
linux-kernel@vger.kernel.org,
linuxppc-embedded@lists.linuxppc.org
Subject: Re: [PATCH,RFC] Add gfp_mask to get_vm_area()
Date: Wed, 2 Oct 2002 11:18:09 +1000 [thread overview]
Message-ID: <20021002011809.GB1848@zax> (raw)
In-Reply-To: <20021001094202.C29814@flint.arm.linux.org.uk>
On Tue, Oct 01, 2002 at 09:42:02AM +0100, Russell King wrote:
>
> On Tue, Oct 01, 2002 at 03:34:17PM +1000, David Gibson wrote:
> > I don't see an easy one: PPC 4xx has non-coherent cache, so we have to
> > mark consistent memory non-cacheable. We want to make the normal
> > lowmem mapping use large page TLB entries, so we can't frob the
> > attribute bits on the pages in place. That means we need to create a
> > new, non-cacheable mapping for the physical RAM we allocate, which in
> > turn means allocating a chunk of kernel virtual memory.
>
> Same problem on ARM. I just haven't got the motivation to rewrite the
> bits of the kernel that need to be rewritten to make it work.
>
> Have you checked that your pte/pmd allocation functions can be called
> from IRQ context as well?
>
> You basically need:
>
> - irq-safe get_vm_area
> - irq-safe pmd_alloc_kernel
> - irq-safe pte_alloc_kernel
>
> Last time I looked, all the above were not irq-safe.
No, I realise they're not safe at the moment - I'm working on that
too.
--
David Gibson | For every complex problem there is a
david@gibson.dropbear.id.au | solution which is simple, neat and
| wrong.
http://www.ozlabs.org/people/dgibson
next prev parent reply other threads:[~2002-10-02 1:12 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-10-01 4:42 [PATCH,RFC] Add gfp_mask to get_vm_area() David Gibson
2002-10-01 4:37 ` David S. Miller
2002-10-01 5:08 ` Andrew Morton
2002-10-01 5:34 ` David Gibson
2002-10-01 8:42 ` Russell King
2002-10-02 1:18 ` David Gibson [this message]
2002-10-03 4:39 ` David Gibson
2002-10-03 4:56 ` David Gibson
2002-10-03 15:18 ` Russell King
2002-10-04 3:27 ` David Gibson
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