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Message-Id: <1629945413.hwbzjjtfbl.astroid@bobo.none>
Date: Thu, 26 Aug 2021 12:46:34 +1000
From: Nicholas Piggin <npiggin@...il.com>
To: Andrew Morton <akpm@...ux-foundation.org>,
Christoph Hellwig <hch@....de>
Cc: linux-kernel@...r.kernel.org, linux-mm@...ck.org,
Peter Zijlstra <peterz@...radead.org>
Subject: Re: [PATCH 2/2] mm: don't allow executable ioremap mappings
Excerpts from Christoph Hellwig's message of August 24, 2021 7:12 pm:
> There is no need to execute from iomem (and most platforms it is
> impossible anyway), so add the pgprot_nx() call similar to vmap.
>
> Signed-off-by: Christoph Hellwig <hch@....de>
> ---
> mm/vmalloc.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index e44983fb2d15..3055f04b486b 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -316,7 +316,7 @@ int ioremap_page_range(unsigned long addr, unsigned long end,
> {
> int err;
>
> - err = vmap_range_noflush(addr, end, phys_addr, prot,
> + err = vmap_range_noflush(addr, end, phys_addr, pgprot_nx(prot),
> ioremap_max_page_shift);
I can't see why this is a problem. powerpcs can but it seems like a bad
idea anyway.
Any point to a WARN_ON or return -EINVAL? Hmm, maybe that doesn't work
for archs that don't support NX. We could add a check for ones that do
support it though... But that's for another patch.
Thanks,
Nick
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