Re: [PATCH v2 2/2] x86/KASLR/64: Determine kernel text mapping size at runtime

From	Baoquan He <bhe@redhat.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH v2 2/2] x86/KASLR/64: Determine kernel text mapping size at runtime
Date	2016-12-10 13:30 +0100
Message-ID	<sMOWS-2d6-33@gated-at.bofh.it> (permalink)
References	<sMuEN-4tz-5@gated-at.bofh.it> <sMuEN-4tz-9@gated-at.bofh.it> <sMNeq-pA-39@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On 12/10/16 at 11:31am, Borislav Petkov wrote:
> On Fri, Dec 09, 2016 at 10:41:58PM +0800, Baoquan He wrote:
> > X86 64 kernel takes KERNEL_IMAGE_SIZE as the kernel text mapping size,
> > and it's fixed as compiling time, changing from 512M to 1G as long as
> > CONFIG_RANDOMIZE_BASE is enabled, though people specify kernel option
> > "nokaslr" explicitly.
> > 
> > This could be a wrong behaviour.
> 
> A bunch of changes just because "this could be a wrong behavior". I'm
> not really persuaded.

Well, then apologize for this wrong expression. It should be "This is
a wrong behaviour."

Whether CONFIG_RANDOMIZE_BASE is yes or not, with 'nokaslr' specified,
Kernel text mapping size should be 512M, just the same as no kaslr code
compiled in.

Thanks
Baoquan

Thread

[PATCH v2 0/2] Determine kernel text mapping size at runtime for x86_64 Baoquan He <bhe@redhat.com> - 2016-12-09 15:50 +0100
  [PATCH v2 2/2] x86/KASLR/64: Determine kernel text mapping size at runtime Baoquan He <bhe@redhat.com> - 2016-12-09 15:50 +0100
    Re: [PATCH v2 2/2] x86/KASLR/64: Determine kernel text mapping size  at runtime Borislav Petkov <bp@suse.de> - 2016-12-10 11:40 +0100
      Re: [PATCH v2 2/2] x86/KASLR/64: Determine kernel text mapping size  at runtime Baoquan He <bhe@redhat.com> - 2016-12-10 13:30 +0100
        Re: [PATCH v2 2/2] x86/KASLR/64: Determine kernel text mapping size  at runtime Borislav Petkov <bp@suse.de> - 2016-12-10 13:40 +0100
          Re: [PATCH v2 2/2] x86/KASLR/64: Determine kernel text mapping size  at runtime Baoquan He <bhe@redhat.com> - 2016-12-10 14:50 +0100
            Re: [PATCH v2 2/2] x86/KASLR/64: Determine kernel text mapping size  at runtime Borislav Petkov <bp@suse.de> - 2016-12-10 17:30 +0100
              Re: [PATCH v2 2/2] x86/KASLR/64: Determine kernel text mapping size  at runtime Baoquan He <bhe@redhat.com> - 2016-12-11 12:00 +0100
                Re: [PATCH v2 2/2] x86/KASLR/64: Determine kernel text mapping size  at runtime Borislav Petkov <bp@suse.de> - 2016-12-11 13:10 +0100
                Re: [PATCH v2 2/2] x86/KASLR/64: Determine kernel text mapping size  at runtime Baoquan He <bhe@redhat.com> - 2016-12-12 03:40 +0100
  [PATCH v2 1/2] x86/64: Make kernel text mapping always take one whole page table in early boot code Baoquan He <bhe@redhat.com> - 2016-12-09 15:50 +0100

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