linux-kernel - Re: [PATCH] UBIFS: endian handling fixes and annotations

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:	Sun, 23 Nov 2008 10:05:34 +0000
From:	Jamie Lokier <jamie@...reable.org>
To:	Sebastian Andrzej Siewior <sebastian@...akpoint.cc>
Cc:	Artem Bityutskiy <dedekind@...radead.org>,
	linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] UBIFS: endian handling fixes and annotations

Sebastian Andrzej Siewior wrote:
> >-	return le32_to_cpu(key->u32[1]) >> UBIFS_S_KEY_BLOCK_BITS;
> >+	return le32_to_cpu(key->j32[1]) >> UBIFS_S_KEY_BLOCK_BITS;
> 
> If you would change such references to something like
> |return le32_to_cpup(&key->j32[1]) >> UBIFS_S_KEY_BLOCK_BITS;
> then on powerpc
> 
>   text    data     bss     dec     hex filename
> 155384    1284      24  156692   26414 ubifs-b4.ko
> 155372    1284      24  156680   26408 ubifs-after.ko
> 
> because now it is possible to load the value as LE from memory instead
> of loading it BE and swapping it afterwads.

If le32_to_cpu used __builtin_bswap32 (a GCC builtin), wouldn't
GCC do this trivial optimisation itself?

-- Jamie
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/