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From: Borislav Petkov <bp@alien8.de>
To: Matt Fleming <matt@codeblueprint.co.uk>,
	Andy Lutomirski <luto@amacapital.net>
Cc: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>,
	"Ravi V. Shankar" <ravi.v.shankar@intel.com>,
	Toshi Kani <toshi.kani@hp.com>, Brian Gerst <brgerst@gmail.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@kernel.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Luis Rodriguez <mcgrof@suse.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Denys Vlasenko <dvlasenk@redhat.com>,
	"H. Peter Anvin" <hpa@zytor.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	ricardo.neri@intel.com, Hugh Dickins <hughd@google.com>,
	Ard Biesheuvel <ard.biesheuvel@linaro.org>
Subject: Re: [tip:efi/core] x86/mm/pat: Use _PAGE_GLOBAL bit for EFI page table mappings
Date: Wed, 24 Feb 2016 17:20:02 +0100	[thread overview]
Message-ID: <20160224162002.GE3888@pd.tnic> (raw)
In-Reply-To: <20160224141046.GA2603@codeblueprint.co.uk>

On Wed, Feb 24, 2016 at 02:10:46PM +0000, Matt Fleming wrote:
> > Normally, the only pages with are _PAGE_GLOBAL are those that are in
> > the normal kernel mappings (swapper_pg_dir and normal mm_struct pgds).
> > By allowing _PAGE_GLOBAL to be set in EFI mappings, you're breaking
> > that convention, which forces you to use extra-expensive
> > __flush_tlb_all calls in efi_call_virt.

Hold on, do you mean the __flush_tlb_all() in the CONFIG_EFI_MIXED code?

That's mixed mode. I think you mean the FLUSH_TLB_ALL in efi_call.
That's EFI on 64-bit but that is mandated by the spec, AFAIR.

So the EFI runtime crap should not change once it is mapped. And those
should be global. It is only natural.

> Nope. The "if (cpa->pgd)" guard ensures that we only call that
> function for the EFI mapping code - no one else sets ->pgd.

But it could - there's no guarantee. kernel_map_pages_in_pgd() is an
exported facility.

-- 
Regards/Gruss,
    Boris.

ECO tip #101: Trim your mails when you reply.

  reply	other threads:[~2016-02-24 16:20 UTC|newest]

Thread overview: 54+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-02-17 12:35 [GIT PULL 00/13] EFI changes for v4.6 part 2 Matt Fleming
2016-02-17 12:35 ` [PATCH 01/13] efi: Reformat GUID tables to follow the format in UEFI spec Matt Fleming
2016-02-22 12:12   ` [tip:efi/core] " =?UTF-8?B?dGlwLWJvdCBmb3IgUGV0ZXIgSm9uZXMgPHRpcGJvdEB6eXRvci5jb20+?=
2016-02-17 12:35 ` [PATCH 02/13] efi/runtime-wrappers: Run UEFI Runtime Services with interrupts enabled Matt Fleming
2016-02-22 12:13   ` [tip:efi/core] " =?UTF-8?B?dGlwLWJvdCBmb3IgQXJkIEJpZXNoZXV2ZWwgPHRpcGJvdEB6eXRvci5jb20+?=
2016-02-17 12:35 ` [PATCH 03/13] x86/mm/pageattr: Use _PAGE_GLOBAL bit for EFI page table mappings Matt Fleming
2016-02-22 12:13   ` [tip:efi/core] x86/mm/pat: " =?UTF-8?B?dGlwLWJvdCBmb3IgU2FpIFByYW5lZXRoIDx0aXBib3RAenl0b3IuY29tPg==?=
2016-02-23 17:47     ` Andy Lutomirski
2016-02-23 18:08       ` Linus Torvalds
2016-02-23 18:12         ` Borislav Petkov
2016-02-24  2:09         ` H. Peter Anvin
2016-02-24  2:13           ` H. Peter Anvin
2016-02-25  8:59         ` Ingo Molnar
2016-02-24  0:50       ` Sai Praneeth Prakhya
2016-02-24  2:43         ` Andy Lutomirski
2016-02-24 14:10           ` Matt Fleming
2016-02-24 16:20             ` Borislav Petkov [this message]
2016-02-24 16:36               ` Andy Lutomirski
2016-02-24 18:56                 ` Linus Torvalds
2016-02-24 19:45                   ` Matt Fleming
2016-02-24 19:50                     ` Andy Lutomirski
2016-02-29 10:56                     ` Sylvain Chouleur
2016-03-02 11:20                       ` Matt Fleming
2016-02-24 19:33                 ` Matt Fleming
2016-02-24 19:49                   ` Andy Lutomirski
2016-02-25  9:06                     ` Ingo Molnar
2016-02-25 15:27                     ` Matt Fleming
2016-02-24 16:41               ` Borislav Petkov
2016-02-24 16:47                 ` Andy Lutomirski
2016-02-24 16:39             ` Andy Lutomirski
2016-02-25 16:00               ` Matt Fleming
2016-02-17 12:35 ` [PATCH 04/13] efi/arm64: Drop __init annotation from handle_kernel_image() Matt Fleming
2016-02-22 12:14   ` [tip:efi/core] " =?UTF-8?B?dGlwLWJvdCBmb3IgQXJkIEJpZXNoZXV2ZWwgPHRpcGJvdEB6eXRvci5jb20+?=
2016-02-17 12:35 ` [PATCH 05/13] arm64: vmlinux.lds.S: Handle .init.rodata.xxx and .init.bss sections Matt Fleming
2016-02-22 12:14   ` [tip:efi/core] arm64/vmlinux.lds.S: " =?UTF-8?B?dGlwLWJvdCBmb3IgQXJkIEJpZXNoZXV2ZWwgPHRpcGJvdEB6eXRvci5jb20+?=
2016-02-17 12:35 ` [PATCH 06/13] efi/efistub: Prevent __init annotations from being used Matt Fleming
2016-02-22 12:14   ` [tip:efi/core] " =?UTF-8?B?dGlwLWJvdCBmb3IgQXJkIEJpZXNoZXV2ZWwgPHRpcGJvdEB6eXRvci5jb20+?=
2016-02-17 12:36 ` [PATCH 07/13] efi/arm-init: Use read-only early mappings Matt Fleming
2016-02-22 12:15   ` [tip:efi/core] " =?UTF-8?B?dGlwLWJvdCBmb3IgQXJkIEJpZXNoZXV2ZWwgPHRpcGJvdEB6eXRvci5jb20+?=
2016-02-17 12:36 ` [PATCH 08/13] efi/arm: Check for LPAE support before booting a LPAE kernel Matt Fleming
2016-02-22 12:15   ` [tip:efi/core] " =?UTF-8?B?dGlwLWJvdCBmb3IgQXJkIEJpZXNoZXV2ZWwgPHRpcGJvdEB6eXRvci5jb20+?=
2016-02-17 12:36 ` [PATCH 09/13] efi/arm64: Check for h/w support before booting a >4 KB granule kernel Matt Fleming
2016-02-22 12:16   ` [tip:efi/core] efi/arm64: Check for h/w support before booting a >4 KB granular kernel =?UTF-8?B?dGlwLWJvdCBmb3IgQXJkIEJpZXNoZXV2ZWwgPHRpcGJvdEB6eXRvci5jb20+?=
2016-03-06  3:35   ` [PATCH 09/13] efi/arm64: Check for h/w support before booting a >4 KB granule kernel Ard Biesheuvel
2016-03-07 11:02     ` Matt Fleming
2016-03-07 11:05       ` Ard Biesheuvel
2016-02-17 12:36 ` [PATCH 10/13] efi/arm*: Perform hardware compatibility check Matt Fleming
2016-02-22 12:16   ` [tip:efi/core] " =?UTF-8?B?dGlwLWJvdCBmb3IgQXJkIEJpZXNoZXV2ZWwgPHRpcGJvdEB6eXRvci5jb20+?=
2016-02-17 12:36 ` [PATCH 11/13] x86/mm/pageattr: Don't implicitly allow _PAGE_RW in kernel_map_pages_in_pgd() Matt Fleming
2016-02-22 12:16   ` [tip:efi/core] x86/mm/pat: " =?UTF-8?B?dGlwLWJvdCBmb3IgU2FpIFByYW5lZXRoIDx0aXBib3RAenl0b3IuY29tPg==?=
2016-02-17 12:36 ` [PATCH 12/13] x86/efi: Map EFI_MEMORY_{XP,RO} memory region bits to EFI page tables Matt Fleming
2016-02-22 12:17   ` [tip:efi/core] " =?UTF-8?B?dGlwLWJvdCBmb3IgU2FpIFByYW5lZXRoIDx0aXBib3RAenl0b3IuY29tPg==?=
2016-02-17 12:36 ` [PATCH 13/13] x86/efi: Only map kernel text for EFI mixed mode Matt Fleming
2016-02-22 12:17   ` [tip:efi/core] " =?UTF-8?B?dGlwLWJvdCBmb3IgU2FpIFByYW5lZXRoIDx0aXBib3RAenl0b3IuY29tPg==?=

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