SRU request submitted: https://lists.ubuntu.com/archives/kernel-team/2018-February/089997.html
** Description changed: + == SRU Justification == + 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. + + This commit was included in mailine as of v4.15-rc5 and fixes commit + 7e381c0ff618. + + == Fix == + commit 371b80447ff33ddac392c189cf884a5a3e18faeb + Author: Nicholas Piggin <npig...@gmail.com> + Date: Wed Dec 6 18:21:14 2017 +1000 + + powerpc/64s: Initialize ISAv3 MMU registers before setting partition + table + + == Regression Potential == + Low. This fix is specific to powerpc. It has also been cc'd to upstream stable, + so it has had additional upstream review. + + + ==Original 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 -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1736145 Title: Ubuntu16.04.03: ISAv3 initialize MMU registers before setting partition table To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu-power-systems/+bug/1736145/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
