linux-kernel - Re: [PATCH 3/4] ARM: drop CONFIG

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <Z1mYufbtXpeEwTAq@shell.armlinux.org.uk>
Date: Wed, 11 Dec 2024 13:50:49 +0000
From: "Russell King (Oracle)" <linux@...linux.org.uk>
To: Linus Walleij <linus.walleij@...aro.org>
Cc: Arnd Bergmann <arnd@...nel.org>, linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org, Arnd Bergmann <arnd@...db.de>,
	linux-mm@...ck.org, linux-rt-devel@...ts.linux.dev,
	Ard Biesheuvel <ardb@...nel.org>,
	Clark Williams <clrkwllms@...nel.org>,
	Jason Baron <jbaron@...mai.com>,
	Josh Poimboeuf <jpoimboe@...nel.org>,
	Mark Rutland <mark.rutland@....com>,
	Matthew Wilcox <willy@...radead.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
	Steven Rostedt <rostedt@...dmis.org>
Subject: Re: [PATCH 3/4] ARM: drop CONFIG_HIGHPTE support

On Wed, Dec 11, 2024 at 02:32:51PM +0100, Linus Walleij wrote:
> On Tue, Dec 10, 2024 at 5:06 PM Arnd Bergmann <arnd@...nel.org> wrote:
> 
> > From: Arnd Bergmann <arnd@...db.de>
> >
> > CONFIG_HIGHPTE was added in linux-2.6.32, a few years before 64-bit
> > support. At the time it made sense, as the CONFIG_ARM_LPAE option allowed
> > systems with 16GB of memory that made lowmem a particularly scarce
> > resource, and the HIGHPTE implementation gave feature parity with 32-bit
> > x86 and frv machines.
> >
> > Since Arm is the last architecture remaining that uses this, and almost
> > no 32-bit machines support more than 4GB of RAM, the cost of continuing
> > to maintain HIGHPTE seems unjustified, so remove it here to allow
> > simplifying the generic page table handling.
> >
> > Link: https://lore.kernel.org/lkml/20241204103042.1904639-8-arnd@kernel.org/T/#u
> > Signed-off-by: Arnd Bergmann <arnd@...db.de>
> 
> I'm in favor of this if the x86 patch goes in. We need to get rid
> of highmem anyway and this will need to happen sooner or later
> either way.

Well... I use highmem routinely.

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!