From: Greg KH <gregkh@linuxfoundation•org>
To: Florian Fainelli <florian.fainelli@broadcom•com>
Cc: stable@vger•kernel.org, Ard Biesheuvel <ardb@kernel•org>,
Anshuman Khandual <anshuman.khandual@arm•com>,
Will Deacon <will@kernel•org>,
Steven Price <steven.price@arm•com>,
Robin Murphy <robin.murphy@arm•com>,
Catalin Marinas <catalin.marinas@arm•com>,
Baruch Siach <baruch@tkos•co.il>,
Petr Tesarik <ptesarik@suse•com>,
Mark Rutland <mark.rutland@arm•com>,
Joey Gouly <joey.gouly@arm•com>,
"Mike Rapoport (IBM)" <rppt@kernel•org>,
Yang Shi <yang@os•amperecomputing.com>,
"moderated list:ARM64 PORT (AARCH64 ARCHITECTURE)"
<linux-arm-kernel@lists•infradead.org>,
open list <linux-kernel@vger•kernel.org>
Subject: Re: [PATCH] arm64: mm: account for hotplug memory when randomizing the linear region
Date: Sun, 12 Jan 2025 12:54:03 +0100 [thread overview]
Message-ID: <2025011247-enable-freezing-ffa2@gregkh> (raw)
In-Reply-To: <62786457-d4a1-4861-8bec-7e478626f4db@broadcom.com>
On Thu, Jan 09, 2025 at 09:01:13AM -0800, Florian Fainelli wrote:
> On 1/9/25 08:54, Florian Fainelli wrote:
> > From: Ard Biesheuvel <ardb@kernel•org>
> >
> > commit 97d6786e0669daa5c2f2d07a057f574e849dfd3e upstream
> >
> > As a hardening measure, we currently randomize the placement of
> > physical memory inside the linear region when KASLR is in effect.
> > Since the random offset at which to place the available physical
> > memory inside the linear region is chosen early at boot, it is
> > based on the memblock description of memory, which does not cover
> > hotplug memory. The consequence of this is that the randomization
> > offset may be chosen such that any hotplugged memory located above
> > memblock_end_of_DRAM() that appears later is pushed off the end of
> > the linear region, where it cannot be accessed.
> >
> > So let's limit this randomization of the linear region to ensure
> > that this can no longer happen, by using the CPU's addressable PA
> > range instead. As it is guaranteed that no hotpluggable memory will
> > appear that falls outside of that range, we can safely put this PA
> > range sized window anywhere in the linear region.
> >
> > Signed-off-by: Ard Biesheuvel <ardb@kernel•org>
> > Cc: Anshuman Khandual <anshuman.khandual@arm•com>
> > Cc: Will Deacon <will@kernel•org>
> > Cc: Steven Price <steven.price@arm•com>
> > Cc: Robin Murphy <robin.murphy@arm•com>
> > Link: https://lore.kernel.org/r/20201014081857.3288-1-ardb@kernel.org
> > Signed-off-by: Catalin Marinas <catalin.marinas@arm•com>
> > Signed-off-by: Florian Fainelli <florian.fainelli@broadcom•com>
>
> Forgot to update the patch subject, but this one is for 5.10.
You also forgot to tell us _why_ this is needed :(
thanks,
greg k-h
next prev parent reply other threads:[~2025-01-12 11:56 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-01-09 16:54 [PATCH stable 5.4] arm64: mm: account for hotplug memory when randomizing the linear region Florian Fainelli
2025-01-09 16:54 ` [PATCH] " Florian Fainelli
2025-01-09 17:01 ` Florian Fainelli
2025-01-12 11:54 ` Greg KH [this message]
2025-01-13 15:44 ` Florian Fainelli
2025-01-20 13:59 ` Greg KH
2025-01-20 16:33 ` Florian Fainelli
2025-01-29 9:17 ` Greg KH
2025-01-29 17:45 ` Florian Fainelli
2025-01-29 22:15 ` Ard Biesheuvel
2025-01-29 23:31 ` Florian Fainelli
2025-01-30 10:05 ` Ard Biesheuvel
2025-01-30 19:12 ` Florian Fainelli
2025-01-12 11:53 ` [PATCH stable 5.4] " Greg KH
2025-01-29 18:05 ` Florian Fainelli
2025-01-30 7:43 ` Greg KH
-- strict thread matches above, loose matches on Subject: below --
2020-10-14 8:18 [PATCH] " Ard Biesheuvel
2020-10-15 10:46 ` Will Deacon
2020-10-16 10:26 ` Anshuman Khandual
2020-10-17 12:39 ` Ard Biesheuvel
2020-11-10 19:14 ` Catalin Marinas
2020-11-11 3:48 ` Anshuman Khandual
2020-11-11 9:11 ` David Hildenbrand
2020-11-12 9:25 ` Catalin Marinas
2020-11-13 3:16 ` Anshuman Khandual
2020-11-13 6:14 ` Ard Biesheuvel
2020-11-13 7:02 ` Anshuman Khandual
2020-11-13 7:06 ` Ard Biesheuvel
2020-11-13 7:40 ` Anshuman Khandual
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=2025011247-enable-freezing-ffa2@gregkh \
--to=gregkh@linuxfoundation$(echo .)org \
--cc=anshuman.khandual@arm$(echo .)com \
--cc=ardb@kernel$(echo .)org \
--cc=baruch@tkos$(echo .)co.il \
--cc=catalin.marinas@arm$(echo .)com \
--cc=florian.fainelli@broadcom$(echo .)com \
--cc=joey.gouly@arm$(echo .)com \
--cc=linux-arm-kernel@lists$(echo .)infradead.org \
--cc=linux-kernel@vger$(echo .)kernel.org \
--cc=mark.rutland@arm$(echo .)com \
--cc=ptesarik@suse$(echo .)com \
--cc=robin.murphy@arm$(echo .)com \
--cc=rppt@kernel$(echo .)org \
--cc=stable@vger$(echo .)kernel.org \
--cc=steven.price@arm$(echo .)com \
--cc=will@kernel$(echo .)org \
--cc=yang@os$(echo .)amperecomputing.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox