linux-kernel - Re: [PATCH v4 05/29] x86/mm: Remove kernel_unmap_pages_in_pgd() and efi_cleanup_page

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Date:	Mon, 27 Jun 2016 09:19:10 +0200
From:	Borislav Petkov <bp@...en8.de>
To:	Andy Lutomirski <luto@...nel.org>, x86@...nel.org
CC:	linux-kernel@...r.kernel.org, linux-arch@...r.kernel.org,
	Nadav Amit <nadav.amit@...il.com>,
	Kees Cook <keescook@...omium.org>,
	Brian Gerst <brgerst@...il.com>,
	"kernel-hardening@...ts.openwall.com" 
	<kernel-hardening@...ts.openwall.com>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Josh Poimboeuf <jpoimboe@...hat.com>,
	Jann Horn <jann@...jh.net>,
	Heiko Carstens <heiko.carstens@...ibm.com>,
	Matt Fleming <matt@...eblueprint.co.uk>,
	linux-efi@...r.kernel.org
Subject: Re: [PATCH v4 05/29] x86/mm: Remove kernel_unmap_pages_in_pgd() and efi_cleanup_page_tables()

Andy Lutomirski <luto@...nel.org> wrote:

>kernel_unmap_pages_in_pgd() is dangerous: if a pgd entry in
>init_mm.pgd were to be cleared, callers would need to ensure that
>the pgd entry hadn't been propagated to any other pgd.
>
>Its only caller was efi_cleanup_page_tables(), and that, in turn,
>was unused, so just delete both functions.  This leaves a couple of
>other helpers unused, so delete them, too.
>
>Cc: Matt Fleming <matt@...eblueprint.co.uk>
>Cc: linux-efi@...r.kernel.org
>Reviewed-by: Matt Fleming <matt@...eblueprint.co.uk>
>Signed-off-by: Andy Lutomirski <luto@...nel.org>
>---
> arch/x86/include/asm/efi.h           |  1 -
> arch/x86/include/asm/pgtable_types.h |  2 --
> arch/x86/mm/pageattr.c               | 28 ----------------------------
> arch/x86/platform/efi/efi.c          |  2 --
> arch/x86/platform/efi/efi_32.c       |  3 ---
> arch/x86/platform/efi/efi_64.c       |  5 -----
> 6 files changed, 41 deletions(-)

Acked-by: Borislav Petkov <bp@...e.de>

-- 
Sent from a small device: formatting sucks and brevity is inevitable.