From: "Russell King (Oracle)" <linux@armlinux.org.uk>
To: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Charlie Jenkins <charlie@rivosinc.com>,
Guenter Roeck <linux@roeck-us.net>,
David Laight <David.Laight@aculab.com>,
Palmer Dabbelt <palmer@dabbelt.com>,
Andrew Morton <akpm@linux-foundation.org>,
Helge Deller <deller@gmx.de>,
"James E.J. Bottomley" <James.Bottomley@hansenpartnership.com>,
Parisc List <linux-parisc@vger.kernel.org>,
Arnd Bergmann <arnd@arndb.de>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Palmer Dabbelt <palmer@rivosinc.com>,
Linux ARM <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH v10] lib: checksum: Use aligned accesses for ip_fast_csum and csum_ipv6_magic tests
Date: Mon, 26 Feb 2024 11:47:44 +0000 [thread overview]
Message-ID: <Zdx6YMRdPmb595M2@shell.armlinux.org.uk> (raw)
In-Reply-To: <7ae930a7-3b10-4470-94ee-89cb650b3349@csgroup.eu>
On Mon, Feb 26, 2024 at 11:34:51AM +0000, Christophe Leroy wrote:
> Le 23/02/2024 à 23:11, Charlie Jenkins a écrit :
> > The test cases for ip_fast_csum and csum_ipv6_magic were not properly
> > aligning the IP header, which were causing failures on architectures
> > that do not support misaligned accesses like some ARM platforms. To
> > solve this, align the data along (14 + NET_IP_ALIGN) bytes which is the
> > standard alignment of an IP header and must be supported by the
> > architecture.
>
> I'm still wondering what we are really trying to fix here.
>
> All other tests are explicitely testing that it works with any alignment.
>
> Shouldn't ip_fast_csum() and csum_ipv6_magic() work for any alignment as
> well ? I would expect it, I see no comment in arm code which explicits
> that assumption around those functions.
No, these functions are explicitly *not* designed to be used with any
alignment. They are for 16-bit alignment only.
I'm not sure where the idea that "any alignment" has come from, but it's
never been the case AFAIK that we've supported that - or if we do now,
that's something which has crept in under the radar.
--
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!
next prev parent reply other threads:[~2024-02-26 11:48 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-23 22:11 [PATCH v10] lib: checksum: Use aligned accesses for ip_fast_csum and csum_ipv6_magic tests Charlie Jenkins
2024-02-25 15:58 ` Guenter Roeck
2024-02-26 11:34 ` Christophe Leroy
2024-02-26 11:47 ` Russell King (Oracle) [this message]
2024-02-26 11:57 ` Christophe Leroy
2024-02-26 12:03 ` Russell King (Oracle)
2024-02-26 16:44 ` Guenter Roeck
2024-02-26 17:50 ` Russell King (Oracle)
2024-02-26 18:35 ` Charlie Jenkins
2024-02-26 19:06 ` Russell King (Oracle)
2024-02-26 19:19 ` Charlie Jenkins
2024-02-26 22:33 ` David Laight
2024-02-26 23:17 ` Charlie Jenkins
2024-02-26 23:48 ` Guenter Roeck
2024-02-27 6:47 ` Christophe Leroy
2024-02-27 10:28 ` Russell King (Oracle)
2024-02-27 11:32 ` Christophe Leroy
2024-02-27 17:54 ` Charlie Jenkins
2024-02-27 18:11 ` Christophe Leroy
2024-02-27 18:21 ` Charlie Jenkins
2024-02-27 18:35 ` Christophe Leroy
2024-02-27 19:04 ` Charlie Jenkins
2024-02-27 19:31 ` Guenter Roeck
2024-02-27 22:44 ` David Laight
2024-02-28 5:19 ` Guenter Roeck
2024-02-28 0:24 ` Charlie Jenkins
2024-02-28 0:21 ` Charlie Jenkins
2024-02-28 7:25 ` Christophe Leroy
2024-02-28 7:59 ` Guenter Roeck
2024-02-28 10:15 ` Geert Uytterhoeven
2024-02-28 15:40 ` Guenter Roeck
2024-02-29 8:07 ` David Gow
2024-02-29 19:38 ` Charlie Jenkins
2024-02-29 20:22 ` Guenter Roeck
2024-03-01 7:00 ` Christophe Leroy
2024-03-01 6:46 ` Christophe Leroy
2024-03-01 16:24 ` Guenter Roeck
2024-03-01 20:47 ` Guenter Roeck
2024-02-27 11:17 ` Geert Uytterhoeven
2024-02-27 17:55 ` Charlie Jenkins
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