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From: Julien Grall <julien.grall@citrix.com>
To: Stefano Stabellini <stefano.stabellini@eu.citrix.com>,
	Ian Campbell <ian.campbell@citrix.com>
Cc: xen-devel@lists.xensource.com
Subject: Re: [PATCH 2/2] xen/arm: support compressed kernels
Date: Wed, 12 Aug 2015 16:27:26 +0100	[thread overview]
Message-ID: <55CB65DE.7080904@citrix.com> (raw)
In-Reply-To: <alpine.DEB.2.02.1508121612300.11337@kaball.uk.xensource.com>

On 12/08/15 16:22, Stefano Stabellini wrote:
>>>  obj-$(perfc)       += perfc.o
>>>  obj-$(crash_debug) += gdbstub.o
>>> diff --git a/xen/include/asm-arm/byteorder.h b/xen/include/asm
>>> -arm/byteorder.h
>>> index 9c712c4..3b7feda 100644
>>> --- a/xen/include/asm-arm/byteorder.h
>>> +++ b/xen/include/asm-arm/byteorder.h
>>> @@ -5,6 +5,8 @@
>>>  
>>>  #include <xen/byteorder/little_endian.h>
>>>  
>>> +#define CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
>>
>> While CONFIG_HAVE_UNALIGNED_ACCESS might be true on arm64 it may not be the
>> case that it is efficient. Also I'm not sure about arm32 at all.
> 
> It is true on arm archs >= v8, so we should be fine. See:

I guess you meant v6?

Although, unaligned access are not allowed in Xen on ARM32. See
arm32/head.S:353

Given that the uncompress code is only used for decompressing DOM0
kernel, I don't think it's worth to enable unaligned access.

Regards,

-- 
Julien Grall

  reply	other threads:[~2015-08-12 15:27 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-08-12 14:47 [PATCH 0/2] support compressed kernels on ARM64 Stefano Stabellini
2015-08-12 14:47 ` [PATCH 1/2] xen: move perform_gunzip to common Stefano Stabellini
2015-08-12 15:14   ` Jan Beulich
2015-08-12 16:15     ` Stefano Stabellini
2015-08-13  6:29       ` Jan Beulich
2015-08-13  9:28         ` Stefano Stabellini
2015-08-13  9:57           ` Jan Beulich
2015-08-13 10:17             ` Ian Campbell
2015-08-13 10:27               ` Jan Beulich
2015-08-12 14:47 ` [PATCH 2/2] xen/arm: support compressed kernels Stefano Stabellini
2015-08-12 15:03   ` Ian Campbell
2015-08-12 15:20     ` Julien Grall
2015-08-12 15:22     ` Stefano Stabellini
2015-08-12 15:27       ` Julien Grall [this message]
2015-08-12 15:35       ` Jan Beulich
2015-08-12 15:40         ` Stefano Stabellini
2015-08-12 15:43       ` Ian Campbell
2015-08-12 15:09   ` Julien Grall
2015-08-12 16:35   ` Andrew Cooper
2015-08-12 17:00     ` Julien Grall

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