<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux.git/arch/powerpc/include/asm/string.h, branch v3.17</title>
<subtitle>Linux kernel source tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/'/>
<entry>
<title>powerpc: memcpy optimization for 64bit LE</title>
<updated>2014-04-30T05:26:18+00:00</updated>
<author>
<name>Philippe Bergheaud</name>
<email>felix@linux.vnet.ibm.com</email>
</author>
<published>2014-04-29T23:12:01+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=00f554fadebb96877ad449758dc90303a9826afe'/>
<id>00f554fadebb96877ad449758dc90303a9826afe</id>
<content type='text'>
Unaligned stores take alignment exceptions on POWER7 running in little-endian.
This is a dumb little-endian base memcpy that prevents unaligned stores.
Once booted the feature fixup code switches over to the VMX copy loops
(which are already endian safe).

The question is what we do before that switch over. The base 64bit
memcpy takes alignment exceptions on POWER7 so we can't use it as is.
Fixing the causes of alignment exception would slow it down, because
we'd need to ensure all loads and stores are aligned either through
rotate tricks or bytewise loads and stores. Either would be bad for
all other 64bit platforms.

[ I simplified the loop a bit - Anton ]

Signed-off-by: Philippe Bergheaud &lt;felix@linux.vnet.ibm.com&gt;
Signed-off-by: Anton Blanchard &lt;anton@samba.org&gt;
Signed-off-by: Benjamin Herrenschmidt &lt;benh@kernel.crashing.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Unaligned stores take alignment exceptions on POWER7 running in little-endian.
This is a dumb little-endian base memcpy that prevents unaligned stores.
Once booted the feature fixup code switches over to the VMX copy loops
(which are already endian safe).

The question is what we do before that switch over. The base 64bit
memcpy takes alignment exceptions on POWER7 so we can't use it as is.
Fixing the causes of alignment exception would slow it down, because
we'd need to ensure all loads and stores are aligned either through
rotate tricks or bytewise loads and stores. Either would be bad for
all other 64bit platforms.

[ I simplified the loop a bit - Anton ]

Signed-off-by: Philippe Bergheaud &lt;felix@linux.vnet.ibm.com&gt;
Signed-off-by: Anton Blanchard &lt;anton@samba.org&gt;
Signed-off-by: Benjamin Herrenschmidt &lt;benh@kernel.crashing.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>powerpc: Use generic memcpy code in little endian</title>
<updated>2013-10-11T05:48:40+00:00</updated>
<author>
<name>Anton Blanchard</name>
<email>anton@samba.org</email>
</author>
<published>2013-09-23T02:04:52+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=de577a356848a629b2c7f252ca3d1bc87375b52b'/>
<id>de577a356848a629b2c7f252ca3d1bc87375b52b</id>
<content type='text'>
We need to fix some endian issues in our memcpy code. For now
just enable the generic memcpy routine for little endian builds.

Signed-off-by: Anton Blanchard &lt;anton@samba.org&gt;
Signed-off-by: Benjamin Herrenschmidt &lt;benh@kernel.crashing.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
We need to fix some endian issues in our memcpy code. For now
just enable the generic memcpy routine for little endian builds.

Signed-off-by: Anton Blanchard &lt;anton@samba.org&gt;
Signed-off-by: Benjamin Herrenschmidt &lt;benh@kernel.crashing.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>powerpc: Move include files to arch/powerpc/include/asm</title>
<updated>2008-08-04T02:02:00+00:00</updated>
<author>
<name>Stephen Rothwell</name>
<email>sfr@canb.auug.org.au</email>
</author>
<published>2008-08-01T05:20:30+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=b8b572e1015f81b4e748417be2629dfe51ab99f9'/>
<id>b8b572e1015f81b4e748417be2629dfe51ab99f9</id>
<content type='text'>
from include/asm-powerpc.  This is the result of a

mkdir arch/powerpc/include/asm
git mv include/asm-powerpc/* arch/powerpc/include/asm

Followed by a few documentation/comment fixups and a couple of places
where &lt;asm-powepc/...&gt; was being used explicitly.  Of the latter only
one was outside the arch code and it is a driver only built for powerpc.

Signed-off-by: Stephen Rothwell &lt;sfr@canb.auug.org.au&gt;
Signed-off-by: Paul Mackerras &lt;paulus@samba.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
from include/asm-powerpc.  This is the result of a

mkdir arch/powerpc/include/asm
git mv include/asm-powerpc/* arch/powerpc/include/asm

Followed by a few documentation/comment fixups and a couple of places
where &lt;asm-powepc/...&gt; was being used explicitly.  Of the latter only
one was outside the arch code and it is a driver only built for powerpc.

Signed-off-by: Stephen Rothwell &lt;sfr@canb.auug.org.au&gt;
Signed-off-by: Paul Mackerras &lt;paulus@samba.org&gt;
</pre>
</div>
</content>
</entry>
</feed>
