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From: "H. Peter Anvin" <hpa@zytor.com>
To: Ian Campbell <ijc@hellion.org.uk>
Cc: linux-kernel@vger.kernel.org,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>
Subject: Re: [PATCH] x86: add a crc32 checksum to the kernel image.
Date: Thu, 31 Jan 2008 16:23:28 -0800	[thread overview]
Message-ID: <47A26680.6060500@zytor.com> (raw)
In-Reply-To: <47A24765.3070300@zytor.com>

H. Peter Anvin wrote:
> 
> Hm.  I have some minor concerns about this:
> 
> * The classical length field is only available in multiples of 16 (I 
> realize your patches change that to some degree, but I'd hate to make 
> the guarantee that the image payload is the last thing in the image -- 
> it loses flexibility for the future.)  The end of the image isn't 
> available in all cases, so this would require padding it out to a 
> 16-byte boundary before appending the CRC32.  An mmap is guaranteed to 
> be zero-padded out to the next page boundary, so explicitly rounding sz 
> up (instead of when calculating sys_size) should do the job.
> 

Thinking about this more carefully, we should probably have it rounded 
up to a 16-byte boundary *including* the CRC32, so the CRC32 is included 
in the notional image.

	-hpa

  reply	other threads:[~2008-02-01  0:24 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-01-31 21:45 [PATCH] x86: define OBJCOPYFLAGS explicitly for each target Ian Campbell
2008-01-31 21:45 ` [PATCH] x86: use ELF format in compressed images Ian Campbell
2008-01-31 21:45   ` [PATCH] x86: add a crc32 checksum to the kernel image Ian Campbell
2008-01-31 21:45     ` [PATCH] x86: bump image header to version 2.08 Ian Campbell
2008-01-31 22:10     ` [PATCH] x86: add a crc32 checksum to the kernel image H. Peter Anvin
2008-02-01  0:23       ` H. Peter Anvin [this message]
2008-02-01  9:02       ` Ian Campbell
2008-02-01 13:07         ` Ingo Molnar
2008-02-06  1:09         ` Randy Dunlap
2008-02-06 20:58           ` Ian Campbell
2008-02-06 21:01             ` Randy Dunlap
2008-02-01  0:43     ` David Newall
2008-02-01  1:16       ` H. Peter Anvin
2008-02-01  5:46         ` David Newall
2008-02-01 10:58         ` Ian Campbell
2008-01-31 22:45 ` [PATCH] x86: define OBJCOPYFLAGS explicitly for each target Ingo Molnar

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