From: Ingo Molnar <mingo@kernel.org>
To: Borislav Petkov <bp@alien8.de>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Matt Fleming <matt@codeblueprint.co.uk>,
Thomas Gleixner <tglx@linutronix.de>,
"H. Peter Anvin" <hpa@zytor.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-efi@vger.kernel.org" <linux-efi@vger.kernel.org>,
Leif Lindholm <leif.lindholm@linaro.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
"stable@vger.kernel.org" <stable@vger.kernel.org>,
Matt Fleming <matt.fleming@intel.com>,
Mark Rutland <mark.rutland@arm.com>,
Mark Salter <msalter@redhat.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Andrew Morton <akpm@linux-foundation.org>,
Andy Lutomirski <luto@kernel.org>,
Denys Vlasenko <dvlasenk@redhat.com>,
Brian Gerst <brgerst@gmail.com>
Subject: Re: [PATCH 2/2] arm64/efi: Don't pad between EFI_MEMORY_RUNTIME regions
Date: Mon, 28 Sep 2015 08:20:15 +0200 [thread overview]
Message-ID: <20150928062015.GB21690@gmail.com> (raw)
In-Reply-To: <20150927104014.GA7631@pd.tnic>
* Borislav Petkov <bp@alien8.de> wrote:
> On Sun, Sep 27, 2015 at 09:06:44AM +0200, Ingo Molnar wrote:
>
> > Could we please re-list all the arguments pro and contra of 1:1 physical
> > mappings, in a post that also explains the background so that more people can
> > chime in, not just people versed in EFI internals? It's very much possible
> > that a bad decision was made.
>
> The main reason why we did the additional, top-down mapping was kexec kernel
> wanting to use UEFI runtime facilities too and the braindead design of
> SetVirtualAddressMap() being callable only once per system boot. So we had to
> have stable mappings which are valid in the kexec-ed kernel too.
>
> But this was long time ago and I most certainly have forgotten all the details.
>
> And now I'm wondering why didn't we do the 1:1 thing and rebuild the exact same
> EFI pagetable in the kexec-ed kernel? Because when we do an EFI call, we switch
> to the special pagetable so why didn't we make the kexec-ed kernel rebuild the
> 1:1 pagetable which it can use for EFI calls...
Yeah.
> Hmm, again, I've forgotten a lot of details so I'm sure Matt will come in and
> say "No, you can't do that because..."
Would be nice to re-examine all this.
Thanks,
Ingo
next prev parent reply other threads:[~2015-09-28 6:20 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-25 22:02 [GIT PULL 0/2] EFI urgent fixes Matt Fleming
2015-09-25 22:02 ` [PATCH 1/2] x86/efi: Map EFI memmap entries in-order at runtime Matt Fleming
2015-09-26 5:56 ` Ingo Molnar
2015-09-26 6:44 ` Ard Biesheuvel
2015-09-26 13:43 ` Matt Fleming
2015-09-27 7:03 ` Ingo Molnar
2015-09-28 6:49 ` Ard Biesheuvel
2015-09-28 8:22 ` Ingo Molnar
2015-09-28 9:51 ` Ard Biesheuvel
2015-09-29 9:12 ` Ingo Molnar
2015-09-29 10:41 ` Ard Biesheuvel
2015-09-29 14:18 ` Matt Fleming
2015-09-29 13:52 ` Matt Fleming
2015-09-26 17:01 ` Andy Lutomirski
2015-09-26 17:20 ` H. Peter Anvin
2015-09-26 18:15 ` Ard Biesheuvel
2015-09-26 19:49 ` H. Peter Anvin
2015-09-26 19:57 ` Matt Fleming
2015-09-26 20:09 ` Ard Biesheuvel
2015-09-26 20:19 ` H. Peter Anvin
2015-09-27 16:30 ` Andy Lutomirski
2015-09-27 18:06 ` Matthew Garrett
2015-09-28 6:16 ` Ingo Molnar
2015-09-28 6:41 ` Matthew Garrett
2015-09-29 21:58 ` Laszlo Ersek
2015-09-30 9:30 ` Ard Biesheuvel
2015-09-30 16:43 ` Andy Lutomirski
2015-09-30 17:24 ` James Bottomley
2015-09-30 0:54 ` H. Peter Anvin
2015-09-26 19:55 ` Matt Fleming
2015-09-27 6:50 ` Ingo Molnar
2015-10-01 12:48 ` [tip:core/urgent] x86/efi: Fix boot crash by mapping EFI memmap entries bottom-up at runtime, instead of top-down tip-bot for Matt Fleming
2015-10-02 9:44 ` Matt Fleming
2015-09-25 22:02 ` [PATCH 2/2] arm64/efi: Don't pad between EFI_MEMORY_RUNTIME regions Matt Fleming
2015-09-26 6:01 ` Ingo Molnar
2015-09-26 7:08 ` Ard Biesheuvel
2015-09-27 7:06 ` Ingo Molnar
2015-09-27 10:40 ` Borislav Petkov
2015-09-28 6:20 ` Ingo Molnar [this message]
2015-09-29 9:31 ` Dave Young
2015-09-29 10:24 ` Borislav Petkov
2015-09-29 14:36 ` Matt Fleming
2015-09-30 0:56 ` H. Peter Anvin
2015-09-30 8:33 ` Borislav Petkov
2015-09-30 1:03 ` H. Peter Anvin
2015-09-30 1:16 ` Andy Lutomirski
2015-09-30 1:19 ` H. Peter Anvin
2015-09-30 4:24 ` Ard Biesheuvel
2015-10-01 10:44 ` Ingo Molnar
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