kernel/arch/powerpc, branch linux-4.1.y

powerpc/eeh: Fix enabling bridge MMIO windows

2018-05-23T01:36:35Z

[ Upstream commit 13a83eac373c49c0a081cbcd137e79210fe78acd ] On boot we save the configuration space of PCIe bridges. We do this so when we get an EEH event and everything gets reset that we can restore them. Unfortunately we save this state before we've enabled the MMIO space on the bridges. Hence if we have to reset the bridge when we come back MMIO is not enabled and we end up taking an PE freeze when the driver starts accessing again. This patch forces the memory/MMIO and bus mastering on when restoring bridges on EEH. Ideally we'd do this correctly by saving the configuration space writes later, but that will have to come later in a larger EEH rewrite. For now we have this simple fix. The original bug can be triggered on a boston machine by doing: echo 0x8000000000000000 > /sys/kernel/debug/powerpc/PCI0001/err_injct_outbound On boston, this PHB has a PCIe switch on it. Without this patch, you'll see two EEH events, 1 expected and 1 the failure we are fixing here. The second EEH event causes the anything under the PHB to disappear (i.e. the i40e eth). With this patch, only 1 EEH event occurs and devices properly recover. Fixes: 652defed4875 ("powerpc/eeh: Check PCIe link after reset") Cc: stable@vger.kernel.org # v3.11+ Reported-by: Pridhiviraj Paidipeddi Signed-off-by: Michael Neuling Acked-by: Russell Currey Signed-off-by: Michael Ellerman Signed-off-by: Sasha Levin

powerpc/powernv: Fix OPAL NVRAM driver OPAL_BUSY loops

2018-05-23T01:36:33Z

[ Upstream commit 3b8070335f751aac9f1526ae2e012e6f5b8b0f21 ] The OPAL NVRAM driver does not sleep in case it gets OPAL_BUSY or OPAL_BUSY_EVENT from firmware, which causes large scheduling latencies, and various lockup errors to trigger (again, BMC reboot can cause it). Fix this by converting it to the standard form OPAL_BUSY loop that sleeps. Fixes: 628daa8d5abf ("powerpc/powernv: Add RTC and NVRAM support plus RTAS fallbacks") Depends-on: 34dd25de9fe3 ("powerpc/powernv: define a standard delay for OPAL_BUSY type retry loops") Cc: stable@vger.kernel.org # v3.2+ Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman Signed-off-by: Sasha Levin

powerpc/powernv: define a standard delay for OPAL_BUSY type retry loops

2018-05-23T01:36:33Z

[ Upstream commit 34dd25de9fe3f60bfdb31b473bf04b28262d0896 ] This is the start of an effort to tidy up and standardise all the delays. Existing loops have a range of delay/sleep periods from 1ms to 20ms, and some have no delay. They all loop forever except rtc, which times out after 10 retries, and that uses 10ms delays. So use 10ms as our standard delay. The OPAL maintainer agrees 10ms is a reasonable starting point. The idea is to use the same recipe everywhere, once this is proven to work then it will be documented as an OPAL API standard. Then both firmware and OS can agree, and if a particular call needs something else, then that can be documented with reasoning. This is not the end-all of this effort, it's just a relatively easy change that fixes some existing high latency delays. There should be provision for standardising timeouts and/or interruptible loops where possible, so non-fatal firmware errors don't cause hangs. Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman Signed-off-by: Sasha Levin

powerpc/64: Fix smp_wmb barrier definition use use lwsync consistently

2018-05-23T01:36:33Z

[ Upstream commit 0bfdf598900fd62869659f360d3387ed80eb71cf ] asm/barrier.h is not always included after asm/synch.h, which meant it was missing __SUBARCH_HAS_LWSYNC, so in some files smp_wmb() would be eieio when it should be lwsync. kernel/time/hrtimer.c is one case. __SUBARCH_HAS_LWSYNC is only used in one place, so just fold it in to where it's used. Previously with my small simulator config, 377 instances of eieio in the tree. After this patch there are 55. Fixes: 46d075be585e ("powerpc: Optimise smp_wmb") Cc: stable@vger.kernel.org # v2.6.29+ Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman Signed-off-by: Sasha Levin

powerpc/powernv: Handle unknown OPAL errors in opal_nvram_write()

2018-05-23T01:36:33Z

[ Upstream commit 741de617661794246f84a21a02fc5e327bffc9ad ] opal_nvram_write currently just assumes success if it encounters an error other than OPAL_BUSY or OPAL_BUSY_EVENT. Have it return -EIO on other errors instead. Fixes: 628daa8d5abf ("powerpc/powernv: Add RTC and NVRAM support plus RTAS fallbacks") Cc: stable@vger.kernel.org # v3.2+ Signed-off-by: Nicholas Piggin Reviewed-by: Vasant Hegde Acked-by: Stewart Smith Signed-off-by: Michael Ellerman Signed-off-by: Sasha Levin

powerpc/spufs: Fix coredump of SPU contexts

2018-05-23T01:36:27Z

[ Upstream commit 99acc9bede06bbb2662aafff51f5b9e529fa845e ] If a process dumps core while it has SPU contexts active then we have code to also dump information about the SPU contexts. Unfortunately it's been broken for 3 1/2 years, and we didn't notice. In commit 7b1f4020d0d1 ("spufs: get rid of dump_emit() wrappers") the nread variable was removed and rc used instead. That means when the loop exits successfully, rc has the number of bytes read, but it's then used as the return value for the function, which should return 0 on success. So fix it by setting rc = 0 before returning in the success case. Fixes: 7b1f4020d0d1 ("spufs: get rid of dump_emit() wrappers") Signed-off-by: Michael Ellerman Acked-by: Jeremy Kerr Signed-off-by: Michael Ellerman Signed-off-by: Sasha Levin

powerpc/[booke|4xx]: Don't clobber TCR[WP] when setting TCR[DIE]

2018-05-23T01:36:26Z

[ Upstream commit 6e2f03e292ef46eed2b31b0a344a91d514f9cd81 ] Prevent a kernel panic caused by unintentionally clearing TCR watchdog bits. At this point in the kernel boot, the watchdog may have already been enabled by u-boot. The original code's attempt to write to the TCR register results in an inadvertent clearing of the watchdog configuration bits, causing the 476 to reset. Signed-off-by: Ivan Mikhaylov Signed-off-by: Michael Ellerman Signed-off-by: Sasha Levin

KVM: PPC: Book3S PR: Check copy_to/from_user return values

2018-05-23T01:36:23Z

[ Upstream commit 67325e988faea735d663799b6d152b5f4254093c ] The PR KVM implementation of the PAPR HPT hypercalls (H_ENTER etc.) access an image of the HPT in userspace memory using copy_from_user and copy_to_user. Recently, the declarations of those functions were annotated to indicate that the return value must be checked. Since this code doesn't currently check the return value, this causes compile warnings like the ones shown below, and since on PPC the default is to compile arch/powerpc with -Werror, this causes the build to fail. To fix this, we check the return values, and if non-zero, fail the hypercall being processed with a H_FUNCTION error return value. There is really no good error return value to use since PAPR didn't envisage the possibility that the hypervisor may not be able to access the guest's HPT, and H_FUNCTION (function not supported) seems as good as any. The typical compile warnings look like this: CC arch/powerpc/kvm/book3s_pr_papr.o /home/paulus/kernel/kvm/arch/powerpc/kvm/book3s_pr_papr.c: In function ‘kvmppc_h_pr_enter’: /home/paulus/kernel/kvm/arch/powerpc/kvm/book3s_pr_papr.c:53:2: error: ignoring return value of ‘copy_from_user’, declared with attribute warn_unused_result [-Werror=unused-result] copy_from_user(pteg, (void __user *)pteg_addr, sizeof(pteg)); ^ /home/paulus/kernel/kvm/arch/powerpc/kvm/book3s_pr_papr.c:74:2: error: ignoring return value of ‘copy_to_user’, declared with attribute warn_unused_result [-Werror=unused-result] copy_to_user((void __user *)pteg_addr, hpte, HPTE_SIZE); ^ ... etc. Signed-off-by: Paul Mackerras Signed-off-by: Sasha Levin

KVM: PPC: Book3S PR: Exit KVM on failed mapping

2018-05-23T01:33:49Z

[ Upstream commit bd9166ffe624000140fc6b606b256df01fc0d060 ] At the moment kvmppc_mmu_map_page() returns -1 if mmu_hash_ops.hpte_insert() fails for any reason so the page fault handler resumes the guest and it faults on the same address again. This adds distinction to kvmppc_mmu_map_page() to return -EIO if mmu_hash_ops.hpte_insert() failed for a reason other than full pteg. At the moment only pSeries_lpar_hpte_insert() returns -2 if plpar_pte_enter() failed with a code other than H_PTEG_FULL. Other mmu_hash_ops.hpte_insert() instances can only fail with -1 "full pteg". With this change, if PR KVM fails to update HPT, it can signal the userspace about this instead of returning to guest and having the very same page fault over and over again. Signed-off-by: Alexey Kardashevskiy Reviewed-by: David Gibson Signed-off-by: Paul Mackerras Signed-off-by: Sasha Levin

powerpc: Avoid taking a data miss on every userspace instruction miss

2018-05-23T01:33:44Z

[ Upstream commit a7a9dcd882a67b68568868b988289fce5ffd8419 ] Early on in do_page_fault() we call store_updates_sp(), regardless of the type of exception. For an instruction miss this doesn't make sense, because we only use this information to detect if a data miss is the result of a stack expansion instruction or not. Worse still, it results in a data miss within every userspace instruction miss handler, because we try and load the very instruction we are about to install a pte for! A simple exec microbenchmark runs 6% faster on POWER8 with this fix: #include #include #include int main(int argc, char *argv[]) { unsigned long left = atol(argv[1]); char leftstr[16]; if (left-- == 0) return 0; sprintf(leftstr, "%ld", left); execlp(argv[0], argv[0], leftstr, NULL); perror("exec failed\n"); return 0; } Pass the number of iterations on the command line (eg 10000) and time how long it takes to execute. Signed-off-by: Anton Blanchard Signed-off-by: Michael Ellerman Signed-off-by: Sasha Levin