linux-kernel - Re: [PATCH 1/2] asm-generic/io.h: suppress endianness warnings for readq() and writeq()

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]

Date:   Tue, 4 Apr 2023 16:35:13 +0100
From:   Jonathan Cameron <Jonathan.Cameron@...wei.com>
To:     Vladimir Oltean <vladimir.oltean@....com>
CC:     Arnd Bergmann <arnd@...db.de>, <linux-arch@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/2] asm-generic/io.h: suppress endianness warnings for
 readq() and writeq()

On Mon,  9 Jan 2023 15:11:52 +0200
Vladimir Oltean <vladimir.oltean@....com> wrote:

> Commit c1d55d50139b ("asm-generic/io.h: Fix sparse warnings on
> big-endian architectures") missed fixing the 64-bit accessors.
> 
> Arnd explains in the attached link why the casts are necessary, even if
> __raw_readq() and __raw_writeq() do not take endian-specific types.
> 
> Link: https://lore.kernel.org/lkml/9105d6fc-880b-4734-857d-e3d30b87ccf6@app.fastmail.com/
> Suggested-by: Arnd Bergmann <arnd@...db.de>
> Signed-off-by: Vladimir Oltean <vladimir.oltean@....com>

Found this when about to send an equivalent patch. Not seeing this in linux-next yet
and would be good to clean the resulting warnings up.

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@...wei.com>

> ---
>  include/asm-generic/io.h | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/include/asm-generic/io.h b/include/asm-generic/io.h
> index 4c44a29b5e8e..d78c3056c98f 100644
> --- a/include/asm-generic/io.h
> +++ b/include/asm-generic/io.h
> @@ -236,7 +236,7 @@ static inline u64 readq(const volatile void __iomem *addr)
>  
>  	log_read_mmio(64, addr, _THIS_IP_, _RET_IP_);
>  	__io_br();
> -	val = __le64_to_cpu(__raw_readq(addr));
> +	val = __le64_to_cpu((__le64 __force)__raw_readq(addr));
>  	__io_ar(val);
>  	log_post_read_mmio(val, 64, addr, _THIS_IP_, _RET_IP_);
>  	return val;
> @@ -287,7 +287,7 @@ static inline void writeq(u64 value, volatile void __iomem *addr)
>  {
>  	log_write_mmio(value, 64, addr, _THIS_IP_, _RET_IP_);
>  	__io_bw();
> -	__raw_writeq(__cpu_to_le64(value), addr);
> +	__raw_writeq((u64 __force)__cpu_to_le64(value), addr);
>  	__io_aw();
>  	log_post_write_mmio(value, 64, addr, _THIS_IP_, _RET_IP_);
>  }