linux-kernel - Re: [PATCH v3 03/13] x86/mm: Remove kernel_unmap_pages_in_pgd() and efi_cleanup_page

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Date:	Tue, 21 Jun 2016 10:53:42 +0100
From:	Matt Fleming <matt@...eblueprint.co.uk>
To:	Andy Lutomirski <luto@...nel.org>
Cc:	x86@...nel.org, linux-kernel@...r.kernel.org,
	linux-arch@...r.kernel.org, Borislav Petkov <bp@...en8.de>,
	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>,
	linux-efi@...r.kernel.org
Subject: Re: [PATCH v3 03/13] x86/mm: Remove kernel_unmap_pages_in_pgd() and
 efi_cleanup_page_tables()

On Mon, 20 Jun, at 04:43:33PM, Andy Lutomirski 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
> 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(-)

Looks fine.

Reviewed-by: Matt Fleming <matt@...eblueprint.co.uk>