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From: Nicholas Piggin <npiggin@gmail.com>
To: Andrew Morton <akpm@linux-foundation.org>,
	Christoph Hellwig <hch@lst.de>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	Peter Zijlstra <peterz@infradead.org>
Subject: Re: [PATCH 2/2] mm: don't allow executable ioremap mappings
Date: Thu, 26 Aug 2021 12:46:34 +1000	[thread overview]
Message-ID: <1629945413.hwbzjjtfbl.astroid@bobo.none> (raw)
In-Reply-To: <20210824091259.1324527-3-hch@lst.de>

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@lst.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

  reply	other threads:[~2021-08-26  2:46 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-24  9:12 small ioremap cleanups Christoph Hellwig
2021-08-24  9:12 ` [PATCH 1/2] mm: move ioremap_page_range to vmalloc.c Christoph Hellwig
2021-08-24 19:51   ` kernel test robot
2021-08-24 19:51     ` kernel test robot
2021-08-26  2:36   ` Nicholas Piggin
2021-08-24  9:12 ` [PATCH 2/2] mm: don't allow executable ioremap mappings Christoph Hellwig
2021-08-26  2:46   ` Nicholas Piggin [this message]
2021-08-26  5:37     ` Christoph Hellwig

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