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From: Matt Fleming <matt-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org>
To: Andy Lutomirski <luto-kltTT9wpgjJwATOyAt5JVQ@public.gmane.org>
Cc: Borislav Petkov <bp-Gina5bIWoIWzQB+pC5nmwQ@public.gmane.org>,
	Ard Biesheuvel
	<ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>,
	Ingo Molnar <mingo-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
	Stephen Smalley <sds-+05T5uksL2qpZYMLLGbcSA@public.gmane.org>,
	"x86-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org"
	<x86-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
	"linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
	<linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	Kees Cook <keescook-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>,
	Thomas Gleixner <tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>,
	"H. Peter Anvin" <hpa-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org>,
	Peter Zijlstra
	<a.p.zijlstra-/NLkJaSkS4VmR6Xm/wNWPw@public.gmane.org>,
	Andy Lutomirski <luto-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
	Denys Vlasenko <dvlasenk-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
	Brian Gerst <brgerst-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
	"linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
	<linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
Subject: Re: [PATCH v2] x86/mm: warn on W+x mappings
Date: Wed, 21 Oct 2015 21:45:22 +0100	[thread overview]
Message-ID: <20151021204522.GB20338@codeblueprint.co.uk> (raw)
In-Reply-To: <CALCETrWwHLnt6=MiyuQY48zEaOUMuFTg1oN3NDdEOxa6XYMgCw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>

On Wed, 21 Oct, at 11:46:53AM, Andy Lutomirski wrote:
>
> If the UEFI stuff is mapped in its own PGD entry, we could just RO
> that entire PGD entry everywhere except the UEFI pgd (and make sure to
> clear G so that the TLB entries get zapped).

What would be the benefit of making it RO as opposed to not having it
mapped at all? The mappings only exist in the trampoline_pgd right now
for x86 which minimizes the potentially vulnerable code paths to the
EFI runtime calls and the suspend/resume code.

  parent reply	other threads:[~2015-10-21 20:45 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <1443814185-21552-1-git-send-email-sds@tycho.nsa.gov>
     [not found] ` <20151003112701.GA4531@gmail.com>
     [not found]   ` <5612CBE8.2010504@tycho.nsa.gov>
     [not found]     ` <20151006073205.GA11115@gmail.com>
     [not found]       ` <5613EAD5.2070405@tycho.nsa.gov>
     [not found]         ` <20151012113605.GB7384@pd.tnic>
     [not found]           ` <20151012113605.GB7384-fF5Pk5pvG8Y@public.gmane.org>
2015-10-12 12:41             ` [PATCH v2] x86/mm: warn on W+x mappings Matt Fleming
2015-10-12 12:49               ` Ingo Molnar
     [not found]                 ` <20151012124936.GA6260-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2015-10-12 12:55                   ` Matt Fleming
     [not found]                     ` <20151012125548.GE2579-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org>
2015-10-12 14:17                       ` Ingo Molnar
     [not found]                         ` <20151012141754.GA6621-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2015-10-12 14:49                           ` Matt Fleming
     [not found]                             ` <20151012144928.GF2579-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org>
2015-10-12 15:34                               ` Ard Biesheuvel
     [not found]                                 ` <CAKv+Gu95NoB5cPqZMeBLn7i0JWDDPKX63FuiMVD94HpbGhKrhA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2015-10-12 15:50                                   ` Matt Fleming
     [not found]                                     ` <20151012155028.GH2579-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org>
2015-10-12 16:43                                       ` Ard Biesheuvel
2015-10-14 15:18                             ` Ingo Molnar
2015-10-14 15:30                               ` Andy Lutomirski
2015-10-14 15:35                                 ` Borislav Petkov
     [not found]                                   ` <20151014153522.GC8218-fF5Pk5pvG8Y@public.gmane.org>
2015-10-15 10:10                                     ` Matt Fleming
     [not found]                                       ` <20151015101016.GB2975-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org>
2015-10-15 10:33                                         ` Borislav Petkov
2015-10-16  1:45                                           ` Ricardo Neri
2015-10-14 21:02                               ` Matt Fleming
2015-10-21  9:42                                 ` Ingo Molnar
     [not found]                                   ` <20151021094242.GA12155-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2015-10-21 12:49                                     ` Ingo Molnar
     [not found]                                       ` <20151021124924.GA19262-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2015-10-21 12:57                                         ` Ard Biesheuvel
2015-10-21 13:24                                           ` Borislav Petkov
     [not found]                                             ` <20151021132430.GD3575-fF5Pk5pvG8Y@public.gmane.org>
2015-10-21 13:28                                               ` Ard Biesheuvel
2015-10-21 14:36                                                 ` Borislav Petkov
     [not found]                                                   ` <20151021143651.GE3575-fF5Pk5pvG8Y@public.gmane.org>
2015-10-21 18:46                                                     ` Andy Lutomirski
     [not found]                                                       ` <CALCETrWwHLnt6=MiyuQY48zEaOUMuFTg1oN3NDdEOxa6XYMgCw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2015-10-21 20:45                                                         ` Matt Fleming [this message]
     [not found]                                                           ` <20151021204522.GB20338-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org>
2015-10-21 20:49                                                             ` Andy Lutomirski
2015-10-21 20:38                                     ` Matt Fleming

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