linux-kernel - Re: [PATCH 1/3] mm/io-mapping: precompute remap protection flags for clarity

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <e3ff5b41-85ed-4a42-aaf0-ab4f16006aab@arm.com>
Date: Mon, 28 Apr 2025 17:45:13 +0530
From: Anshuman Khandual <anshuman.khandual@....com>
To: Ye Liu <ye.liu@...ux.dev>, akpm@...ux-foundation.org
Cc: linux-kernel@...r.kernel.org, linux-mm@...ck.org, rppt@...nel.org,
 lorenzo.stoakes@...cle.com, Liam.Howlett@...cle.com, david@...hat.com,
 harry.yoo@...cle.com, riel@...riel.com, vbabka@...e.cz, liuye@...inos.cn
Subject: Re: [PATCH 1/3] mm/io-mapping: precompute remap protection flags for
 clarity

On 4/27/25 15:34, Ye Liu wrote:
> From: Ye Liu <liuye@...inos.cn>
> 
> In io_mapping_map_user(), precompute the page protection flags in a local
> variable before calling remap_pfn_range_notrack().
> 
> No functional change.
> 
> Signed-off-by: Ye Liu <liuye@...inos.cn>
> ---
>  mm/io-mapping.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/mm/io-mapping.c b/mm/io-mapping.c
> index 01b362799930..f44a6a134712 100644
> --- a/mm/io-mapping.c
> +++ b/mm/io-mapping.c
> @@ -21,9 +21,10 @@ int io_mapping_map_user(struct io_mapping *iomap, struct vm_area_struct *vma,
>  	if (WARN_ON_ONCE((vma->vm_flags & expected_flags) != expected_flags))
>  		return -EINVAL;
>  
> +	pgprot_t remap_prot = __pgprot((pgprot_val(iomap->prot) & _PAGE_CACHE_MASK) |
> +				       (pgprot_val(vma->vm_page_prot) & ~_PAGE_CACHE_MASK));
> +
>  	/* We rely on prevalidation of the io-mapping to skip track_pfn(). */
> -	return remap_pfn_range_notrack(vma, addr, pfn, size,
> -		__pgprot((pgprot_val(iomap->prot) & _PAGE_CACHE_MASK) |
> -			 (pgprot_val(vma->vm_page_prot) & ~_PAGE_CACHE_MASK)));
> +	return remap_pfn_range_notrack(vma, addr, pfn, size, remap_prot);
>  }
>  EXPORT_SYMBOL_GPL(io_mapping_map_user);

Reviewed-by: Anshuman Khandual <anshuman.khandual@....com>