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Subject: Re: KAISER memory layout (Re: [PATCH 06/23] x86, kaiser: introduce
 user-mapped percpu areas)
To: Andy Lutomirski <luto@kernel.org>
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        "linux-mm@kvack.org" <linux-mm@kvack.org>, moritz.lipp@iaik.tugraz.at,
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        Linus Torvalds <torvalds@linux-foundation.org>,
        Kees Cook <keescook@google.com>, Hugh Dickins <hughd@google.com>,
        X86 ML <x86@kernel.org>, Borislav Petkov <bp@alien8.de>,
        Josh Poimboeuf <jpoimboe@redhat.com>
From: Dave Hansen <dave.hansen@linux.intel.com>
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Date: Thu, 2 Nov 2017 09:36:37 -0700
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On 11/02/2017 02:41 AM, Andy Lutomirski wrote:
> 
>  - The GDT array.
>  - The IDT.
>  - The vsyscall page.  We can make this be _PAGE_USER.
>  - The TSS.
>  - The per-cpu entry stack.  Let's make it one page with guard pages
> on either side.  This can replace rsp_scratch.
>  - cpu_current_top_of_stack.  This could be in the same page as the TSS.
>  - The entry text.
>  - The percpu IST (aka "EXCEPTION") stacks.
> 
> That's it.

The PEBS/BTS buffers need it too, I think:

https://git.kernel.org/pub/scm/linux/kernel/git/daveh/x86-kaiser.git/commit/?h=kaiser-414rc6-20171031&id=97a334906d7853a8109b295ef94f3991418d0c07