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From: "H. Peter Anvin" <hpa@zytor.com>
To: Kees Cook <keescook@chromium.org>
Cc: LKML <linux-kernel@vger.kernel.org>, Baoquan He <bhe@redhat.com>,
	Vivek Goyal <vgoyal@redhat.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, "x86@kernel.org" <x86@kernel.org>,
	"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
	Wei Yongjun <yongjun_wei@trendmicro.com.cn>,
	Pavel Machek <pavel@ucw.cz>
Subject: Re: [PATCH] x86, kaslr: avoid setup_data when picking location
Date: Wed, 01 Oct 2014 11:13:55 -0700	[thread overview]
Message-ID: <542C4463.1020208@zytor.com> (raw)
In-Reply-To: <CAGXu5jLK-k4JZO4eZSasRuSSQxeru94U9whMPcgD6iin40VVTA@mail.gmail.com>

On 10/01/2014 11:08 AM, Kees Cook wrote:
>>
>> The use of (u64) in the assignment to avoid.start gives a nuisance
>> warning on 32 bits.
> 
> Ah, good catch! This should be (unsigned long), I think. Shall I send
> a follow-up patch, or do you want to fix this directly?
> 

Please do.

In theory it is possible for a bootloader to put an object above 4G even
for a 32-bit kernel, but that is likely to break any kind of other
things, so I'm not worried about it.  You don't need to worry about
avoiding such a zone, the problem is mostly that you can't follow the
list any further without adding PAE-handling code.

	-hpa



      reply	other threads:[~2014-10-01 18:14 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-09-11 16:19 [PATCH] x86, kaslr: avoid setup_data when picking location Kees Cook
2014-09-19 11:49 ` [tip:x86/urgent] x86/kaslr: Avoid the setup_data area " tip-bot for Kees Cook
2014-10-01 18:01 ` [PATCH] x86, kaslr: avoid setup_data " H. Peter Anvin
2014-10-01 18:08   ` Kees Cook
2014-10-01 18:13     ` H. Peter Anvin [this message]

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