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From: Anton Blanchard <anton@samba.org>
To: benh@kernel.crashing.org, paulus@samba.org, paulmck@linux.vnet.ibm.com
Cc: linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH] powerpc: Make 64-bit non-VMX __copy_tofrom_user bi-endian
Date: Wed, 18 Dec 2013 21:15:02 +1100	[thread overview]
Message-ID: <20131218211502.034c3eb0@kryten> (raw)
In-Reply-To: <20131218092957.4a12cbcf@kryten>


Hi,

> [ This is a rare but nasty LE issue. Most of the time we use the
> POWER7 optimised __copy_tofrom_user_power7 loop, but when it hits an
> exception we fall back to the base __copy_tofrom_user loop. - Anton ]

To try and catch any screw ups in our ppc64 memcpy and copy_tofrom_user
loops, I wrote a quick test:

http://ozlabs.org/~anton/junkcode/validate_kernel_copyloops.tar.gz

"make check" runs through all source and destination alignments for a
range of sizes. It verifies the data was copied correctly and the
redzone before and after were untouched.

It tests:

copyuser_64
copyuser_power7
memcpy_64
memcpy_power7

memcpy_64 is currently unused on LE, but I added Paul McKenney's LE
fixes regardless. copyuser_64 has the same LE fix (posted yesterday).
All loops pass the test on both LE and BE.

Anton

  reply	other threads:[~2013-12-18 10:15 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-12-17 22:29 [PATCH] powerpc: Make 64-bit non-VMX __copy_tofrom_user bi-endian Anton Blanchard
2013-12-18 10:15 ` Anton Blanchard [this message]
2013-12-19 13:17   ` Michael Ellerman
2013-12-24  1:02     ` Anton Blanchard
2013-12-24  3:34       ` Michael Ellerman

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