From: Catalin Marinas <catalin.marinas@arm.com> To: Anshuman Khandual <anshuman.khandual@arm.com> Cc: linux-arm-kernel@lists.infradead.org, Ard Biesheuvel <ardb@kernel.org>, Will Deacon <will@kernel.org>, linux-kernel@vger.kernel.org, Mark Rutland <mark.rutland@arm.com>, Steve Capper <steve.capper@arm.com>, Mark Brown <broonie@kernel.org>, Marc Zyngier <maz@kernel.org>, gshan@redhat.com, Robin Murphy <robin.murphy@arm.com>, Steven Price <steven.price@arm.com>, David Hildenbrand <david@redhat.com> Subject: Re: [PATCH] arm64: mm: account for hotplug memory when randomizing the linear region Date: Thu, 12 Nov 2020 09:25:58 +0000 [thread overview] Message-ID: <20201112092558.GC29613@gaia> (raw) In-Reply-To: <a330440d-803b-5aa2-0092-a18317819850@arm.com> Hi Anshuman, On Wed, Nov 11, 2020 at 09:18:56AM +0530, Anshuman Khandual wrote: > On 11/11/20 12:44 AM, Catalin Marinas wrote: > > On Wed, 14 Oct 2020 10:18:57 +0200, Ard Biesheuvel wrote: > >> 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. > >> > >> [...] > > > > Applied to arm64 (for-next/mem-hotplug), thanks! > > > > [1/1] arm64: mm: account for hotplug memory when randomizing the linear region > > https://git.kernel.org/arm64/c/97d6786e0669 > > Got delayed and never made here in time, sorry about that. Nonetheless, > I have got something working with respect to the generic mechanism that > David Hildenbrand had asked for earlier. > > https://patchwork.kernel.org/project/linux-arm-kernel/patch/1600332402-30123-1-git-send-email-anshuman.khandual@arm.com/ There was a lot of discussion around this patch but I haven't seen any new version posted. > I am wondering if we could instead consider merging the above patch with > a small change that Ard had pointed out earlier [1], I will send out a > revision if required. If your patch fixes the randomisation issue that Ard addressed, I'm happy to replace that with your patch. But please post a new version and get some acks in place from the parties involved in the discussion. Thanks. -- Catalin
WARNING: multiple messages have this Message-ID (diff)
From: Catalin Marinas <catalin.marinas@arm.com> To: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Mark Rutland <mark.rutland@arm.com>, gshan@redhat.com, Steve Capper <steve.capper@arm.com>, Marc Zyngier <maz@kernel.org>, David Hildenbrand <david@redhat.com>, linux-kernel@vger.kernel.org, Steven Price <steven.price@arm.com>, Mark Brown <broonie@kernel.org>, Will Deacon <will@kernel.org>, Ard Biesheuvel <ardb@kernel.org>, linux-arm-kernel@lists.infradead.org, Robin Murphy <robin.murphy@arm.com> Subject: Re: [PATCH] arm64: mm: account for hotplug memory when randomizing the linear region Date: Thu, 12 Nov 2020 09:25:58 +0000 [thread overview] Message-ID: <20201112092558.GC29613@gaia> (raw) In-Reply-To: <a330440d-803b-5aa2-0092-a18317819850@arm.com> Hi Anshuman, On Wed, Nov 11, 2020 at 09:18:56AM +0530, Anshuman Khandual wrote: > On 11/11/20 12:44 AM, Catalin Marinas wrote: > > On Wed, 14 Oct 2020 10:18:57 +0200, Ard Biesheuvel wrote: > >> 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. > >> > >> [...] > > > > Applied to arm64 (for-next/mem-hotplug), thanks! > > > > [1/1] arm64: mm: account for hotplug memory when randomizing the linear region > > https://git.kernel.org/arm64/c/97d6786e0669 > > Got delayed and never made here in time, sorry about that. Nonetheless, > I have got something working with respect to the generic mechanism that > David Hildenbrand had asked for earlier. > > https://patchwork.kernel.org/project/linux-arm-kernel/patch/1600332402-30123-1-git-send-email-anshuman.khandual@arm.com/ There was a lot of discussion around this patch but I haven't seen any new version posted. > I am wondering if we could instead consider merging the above patch with > a small change that Ard had pointed out earlier [1], I will send out a > revision if required. If your patch fixes the randomisation issue that Ard addressed, I'm happy to replace that with your patch. But please post a new version and get some acks in place from the parties involved in the discussion. Thanks. -- Catalin _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2020-11-12 9:26 UTC|newest] Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-10-14 8:18 [PATCH] arm64: mm: account for hotplug memory when randomizing the linear region 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 2020-11-10 19:14 ` Catalin Marinas 2020-11-11 3:48 ` Anshuman Khandual 2020-11-11 3:48 ` Anshuman Khandual 2020-11-11 9:11 ` David Hildenbrand 2020-11-11 9:11 ` David Hildenbrand 2020-11-12 9:25 ` Catalin Marinas [this message] 2020-11-12 9:25 ` Catalin Marinas 2020-11-13 3:16 ` Anshuman Khandual 2020-11-13 3:16 ` Anshuman Khandual 2020-11-13 6:14 ` Ard Biesheuvel 2020-11-13 6:14 ` Ard Biesheuvel 2020-11-13 7:02 ` Anshuman Khandual 2020-11-13 7:02 ` Anshuman Khandual 2020-11-13 7:06 ` Ard Biesheuvel 2020-11-13 7:06 ` Ard Biesheuvel 2020-11-13 7:40 ` Anshuman Khandual 2020-11-13 7:40 ` Anshuman Khandual
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