From mboxrd@z Thu Jan 1 00:00:00 1970 From: msalter@redhat.com (Mark Salter) Date: Fri, 15 Aug 2014 10:35:55 -0400 Subject: [PATCH v2 1/3] arm64: spin-table: handle unmapped cpu-release-addrs In-Reply-To: References: <20140813125844.GE32644@leverpostej> <20140814171323.GH9039@arm.com> <20140815115714.GP27466@arm.com> <20140815125324.GQ27466@arm.com> Message-ID: <1408113355.599.146.camel@deneb.redhat.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Fri, 2014-08-15 at 15:28 +0200, Ard Biesheuvel wrote: > On 15 August 2014 14:53, Will Deacon wrote: > > On Fri, Aug 15, 2014 at 01:07:16PM +0100, Ard Biesheuvel wrote: > >> On 15 August 2014 13:57, Will Deacon wrote: > >> > On Thu, Aug 14, 2014 at 07:10:13PM +0100, Ard Biesheuvel wrote: > >> >> Patch 3/3 makes the EFI stub load Image at the lowest 2 meg boundary + > >> >> TEXT_OFFSET instead of erroring out when base of DRAM + TEXT_OFFSET is > >> >> occupied. This is necessary as the randomized TEXT_OFFSET could > >> >> potentially conflict with reserved areas at the base of DRAM if a low > >> >> value happens to be chosen. > >> >> > >> >> Patch 1/3 fixes the resulting breakage on APM Mustang in bringing up > >> >> the secondaries, as on that board in particular, the reserved area at > >> >> the base of DRAM contains the holding pen, and loading Image higher up > >> >> makes the mailbox inaccessible through the linear mapping hence the > >> >> need for ioremap_cache() > >> >> > >> >> Patch 2/3 is also a fix for a potential issue on UEFI boot, but it is > >> >> unrelated to 1/3 and 3/3 > >> > > >> > I was planning to take all of these for 3.18 as there's no regression here > >> > (the fuzzing is a new debug feature and defaults to `n'). Do you think these > >> > qualify as -rc1 material? > >> > > >> > >> Considering that TEXT_OFFSET fuzzing is recommended to be turned on > >> for distro kernels, I would say this is definitely appropriate for > >> 3.17 > > > > Whilst I see that in the commit log, the same recommendation doesn't appear > > in the Kconfig text and I'm not sure that it's such a wise thing to say > > either. From a distribution's point of view, I think I'd want any kernel > > issues to be as reproducible as possible, and fuzzing the text offset seems > > to go against that. > > > > OK. There is one other real world issue that 3/3 addresses, which are > platforms that have memreserves at the base of DRAM containing bits of > UEFI itself (this is what got this whole discussion going in the first > place). Currently, we cannot boot via UEFI on these platforms, as the > EFI stub will only consider base of DRAM + TEXT_OFFSET as an option, > and fail the boot if it is not available. > > If this is something that could wait until 3.18 as well (Mark S?), > then it's fine by me. > I don't see a problem with waiting until 3.18.