Public bug reported: == Comment: #0 - Breno Leitao <bren...@br.ibm.com> - 2017-12-04 05:50:27 == kexec can leave MMU registers set, PIDR in particular, when booting the new kernel. The boot sequence does not zero PIDR ever, and it only gets changed as CPUs first switch to userspace processes. This can leave a window where speculative accesses from a CPU to quadrant 0 can pick up translations in the partition table that may be set up for processes running on other CPUs. These cached translations will not be involved in the invalidation protocol, so we can end with stable TLB and PWC.
We need to have this patch included in Ubuntu kernel. https://lists.ozlabs.org/pipermail/linuxppc-dev/2017-December/166424.html We do not have commit id, but once we have, I will post here. There is no need to include the patch prior to upstream acceptance. == Comment: #2 - VIPIN K. PARASHAR <vipar...@in.ibm.com> - 2017-12-04 06:57:52 == (In reply to comment #0) > > We need to have this patch included in Ubuntu kernel. > https://lists.ozlabs.org/pipermail/linuxppc-dev/2017-December/166424.html > > We do not have commit id, but once we have, I will post here. There is no > need to include the patch prior to upstream acceptance. > .. Patch subject reads as follows: [PATCH] powerpc/64s: ISAv3 initialize MMU registers before setting partition table ** Affects: linux (Ubuntu) Importance: Undecided Assignee: Ubuntu on IBM Power Systems Bug Triage (ubuntu-power-triage) Status: New ** Tags: architecture-ppc64le bugnameltc-162133 severity-high targetmilestone-inin16043 ** Tags added: architecture-ppc64le bugnameltc-162133 severity-high targetmilestone-inin16043 ** Changed in: ubuntu Assignee: (unassigned) => Ubuntu on IBM Power Systems Bug Triage (ubuntu-power-triage) ** Package changed: ubuntu => linux (Ubuntu) -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1736145 Title: Ubuntu16.04.03: ISAv3 initialize MMU registers before setting partition table Status in linux package in Ubuntu: New Bug description: == Comment: #0 - Breno Leitao <bren...@br.ibm.com> - 2017-12-04 05:50:27 == kexec can leave MMU registers set, PIDR in particular, when booting the new kernel. The boot sequence does not zero PIDR ever, and it only gets changed as CPUs first switch to userspace processes. This can leave a window where speculative accesses from a CPU to quadrant 0 can pick up translations in the partition table that may be set up for processes running on other CPUs. These cached translations will not be involved in the invalidation protocol, so we can end with stable TLB and PWC. We need to have this patch included in Ubuntu kernel. https://lists.ozlabs.org/pipermail/linuxppc-dev/2017-December/166424.html We do not have commit id, but once we have, I will post here. There is no need to include the patch prior to upstream acceptance. == Comment: #2 - VIPIN K. PARASHAR <vipar...@in.ibm.com> - 2017-12-04 06:57:52 == (In reply to comment #0) > > We need to have this patch included in Ubuntu kernel. > https://lists.ozlabs.org/pipermail/linuxppc-dev/2017-December/166424.html > > We do not have commit id, but once we have, I will post here. There is no > need to include the patch prior to upstream acceptance. > .. Patch subject reads as follows: [PATCH] powerpc/64s: ISAv3 initialize MMU registers before setting partition table To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1736145/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
