[<prev] [next>] [<thread-prev] [day] [month] [year] [list]
Message-Id: <20160127114611.25531afcfabf03febc134b48@linux-foundation.org>
Date: Wed, 27 Jan 2016 11:46:11 -0800
From: Andrew Morton <akpm@...ux-foundation.org>
To: Ard Biesheuvel <ard.biesheuvel@...aro.org>
Cc: linux-alpha@...r.kernel.org,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"linux-arm-kernel@...ts.infradead.org"
<linux-arm-kernel@...ts.infradead.org>,
"linux-ia64@...r.kernel.org" <linux-ia64@...r.kernel.org>,
linux-s390@...r.kernel.org, "x86@...nel.org" <x86@...nel.org>,
"hpa@...or.com" <hpa@...or.com>,
Heiko Carstens <heiko.carstens@...ibm.com>,
Richard Henderson <rth@...ddle.net>,
Tony Luck <tony.luck@...el.com>,
Will Deacon <will.deacon@....com>, Helge Deller <deller@....de>
Subject: Re: [PATCH v2 resend 6/6] arm64: switch to relative exception
tables
On Wed, 27 Jan 2016 20:39:23 +0100 Ard Biesheuvel <ard.biesheuvel@...aro.org> wrote:
> On 27 January 2016 at 20:35, Andrew Morton <akpm@...ux-foundation.org> wrote:
> > On Wed, 27 Jan 2016 11:55:23 +0100 Ard Biesheuvel <ard.biesheuvel@...aro.org> wrote:
> >
> >> Instead of using absolute addresses for both the exception location
> >> and the fixup, use offsets relative to the exception table entry values.
> >> Not only does this cut the size of the exception table in half, it is
> >> also a prerequisite for KASLR, since absolute exception table entries
> >> are subject to dynamic relocation, which is incompatible with the sorting
> >> of the exception table that occurs at build time.
> >>
> >> This patch also introduces the _ASM_EXTABLE preprocessor macro (which
> >> exists on x86 as well) and its _asm_extable assembly counterpart, as
> >> shorthands to emit exception table entries.
> >
> > checkpatch speaketh truth:
> >
> > ERROR: #define of 'ARCH_HAS_RELATIVE_EXTABLE' is wrong - use Kconfig variables or standard guards instead
> > #113: FILE: arch/arm64/include/asm/uaccess.h:56:
>
> That may be true, but it extends an established pattern of #defines in
> the various uaccess.h versions, i.e., ARCH_HAS_SORT_EXTABLE, and
> ARCH_HAS_SEARCH_EXTABLE
True. But now we have two things to fix, not one ;)
Whatever. Later.
Powered by blists - more mailing lists