linux-kernel - Re: [PATCH] drivers/block/xsysace - replace in(out)_8/in(out)_be16/in(out)

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, 05 Feb 2013 23:29:43 +1100
From:	Benjamin Herrenschmidt <benh@...nel.crashing.org>
To:	Vineet Gupta <Vineet.Gupta1@...opsys.com>
Cc:	Michal Simek <monstr@...str.eu>, Arnd Bergmann <arnd@...db.de>,
	Alexey Brodkin <Alexey.Brodkin@...opsys.com>,
	linux-kernel@...r.kernel.org, grant.likely@...retlab.ca,
	alan@...rguk.ukuu.org.uk, geert@...ux-m68k.org,
	dahinds@...rs.sourceforge.net, Noam Camus <noamc@...hip.com>
Subject: Re: [PATCH] drivers/block/xsysace - replace
 in(out)_8/in(out)_be16/in(out)_le16 with generic iowrite(read)8/16(be)

On Tue, 2013-02-05 at 17:39 +0530, Vineet Gupta wrote:
> Am I correct in understanding that "be" suffix here reflects the byte ordering of
> the device and not the CPU. So for a BE device, driver using ioread32be on LE
> processor will get MSB first data - and accessor will swap the bytes to make it
> lsb first in register, while on BE processor, the lanes to memory are swapped,
> causing the msb first word to be flipped before ending up in the cpu register - so
> in the end, CPU register on either will have the exact same value. Correct ?

Yes. That's how ioread32 and ioread32be are defined. They relate to the device
endianness regardless of the CPU endianness.

ioread32 -> little endian device
ioread32be -> big endian device

Cheers,
Ben.


--
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/