kernel.git/arch/powerpc/platforms, branch linux-5.7.y

powerpc/pseries: Do not initiate shutdown when system is running on UPS

2020-08-26T09:42:23Z

commit 90a9b102eddf6a3f987d15f4454e26a2532c1c98 upstream. As per PAPR we have to look for both EPOW sensor value and event modifier to identify the type of event and take appropriate action. In LoPAPR v1.1 section 10.2.2 includes table 136 "EPOW Action Codes": SYSTEM_SHUTDOWN 3 The system must be shut down. An EPOW-aware OS logs the EPOW error log information, then schedules the system to be shut down to begin after an OS defined delay internal (default is 10 minutes.) Then in section 10.3.2.2.8 there is table 146 "Platform Event Log Format, Version 6, EPOW Section", which includes the "EPOW Event Modifier": For EPOW sensor value = 3 0x01 = Normal system shutdown with no additional delay 0x02 = Loss of utility power, system is running on UPS/Battery 0x03 = Loss of system critical functions, system should be shutdown 0x04 = Ambient temperature too high All other values = reserved We have a user space tool (rtas_errd) on LPAR to monitor for EPOW_SHUTDOWN_ON_UPS. Once it gets an event it initiates shutdown after predefined time. It also starts monitoring for any new EPOW events. If it receives "Power restored" event before predefined time it will cancel the shutdown. Otherwise after predefined time it will shutdown the system. Commit 79872e35469b ("powerpc/pseries: All events of EPOW_SYSTEM_SHUTDOWN must initiate shutdown") changed our handling of the "on UPS/Battery" case, to immediately shutdown the system. This breaks existing setups that rely on the userspace tool to delay shutdown and let the system run on the UPS. Fixes: 79872e35469b ("powerpc/pseries: All events of EPOW_SYSTEM_SHUTDOWN must initiate shutdown") Cc: stable@vger.kernel.org # v4.0+ Signed-off-by: Vasant Hegde [mpe: Massage change log and add PAPR references] Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200820061844.306460-1-hegdevasant@linux.vnet.ibm.com Signed-off-by: Greg Kroah-Hartman

powerpc/pseries/hotplug-cpu: wait indefinitely for vCPU death

2020-08-26T09:42:22Z

[ Upstream commit 801980f6497946048709b9b09771a1729551d705 ] For a power9 KVM guest with XIVE enabled, running a test loop where we hotplug 384 vcpus and then unplug them, the following traces can be seen (generally within a few loops) either from the unplugged vcpu: cpu 65 (hwid 65) Ready to die... Querying DEAD? cpu 66 (66) shows 2 list_del corruption. next->prev should be c00a000002470208, but was c00a000002470048 ------------[ cut here ]------------ kernel BUG at lib/list_debug.c:56! Oops: Exception in kernel mode, sig: 5 [#1] LE SMP NR_CPUS=2048 NUMA pSeries Modules linked in: fuse nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 ... CPU: 66 PID: 0 Comm: swapper/66 Kdump: loaded Not tainted 4.18.0-221.el8.ppc64le #1 NIP: c0000000007ab50c LR: c0000000007ab508 CTR: 00000000000003ac REGS: c0000009e5a17840 TRAP: 0700 Not tainted (4.18.0-221.el8.ppc64le) MSR: 800000000282b033 CR: 28000842 XER: 20040000 ... NIP __list_del_entry_valid+0xac/0x100 LR __list_del_entry_valid+0xa8/0x100 Call Trace: __list_del_entry_valid+0xa8/0x100 (unreliable) free_pcppages_bulk+0x1f8/0x940 free_unref_page+0xd0/0x100 xive_spapr_cleanup_queue+0x148/0x1b0 xive_teardown_cpu+0x1bc/0x240 pseries_mach_cpu_die+0x78/0x2f0 cpu_die+0x48/0x70 arch_cpu_idle_dead+0x20/0x40 do_idle+0x2f4/0x4c0 cpu_startup_entry+0x38/0x40 start_secondary+0x7bc/0x8f0 start_secondary_prolog+0x10/0x14 or on the worker thread handling the unplug: pseries-hotplug-cpu: Attempting to remove CPU , drc index: 1000013a Querying DEAD? cpu 314 (314) shows 2 BUG: Bad page state in process kworker/u768:3 pfn:95de1 cpu 314 (hwid 314) Ready to die... page:c00a000002577840 refcount:0 mapcount:-128 mapping:0000000000000000 index:0x0 flags: 0x5ffffc00000000() raw: 005ffffc00000000 5deadbeef0000100 5deadbeef0000200 0000000000000000 raw: 0000000000000000 0000000000000000 00000000ffffff7f 0000000000000000 page dumped because: nonzero mapcount Modules linked in: kvm xt_CHECKSUM ipt_MASQUERADE xt_conntrack ... CPU: 0 PID: 548 Comm: kworker/u768:3 Kdump: loaded Not tainted 4.18.0-224.el8.bz1856588.ppc64le #1 Workqueue: pseries hotplug workque pseries_hp_work_fn Call Trace: dump_stack+0xb0/0xf4 (unreliable) bad_page+0x12c/0x1b0 free_pcppages_bulk+0x5bc/0x940 page_alloc_cpu_dead+0x118/0x120 cpuhp_invoke_callback.constprop.5+0xb8/0x760 _cpu_down+0x188/0x340 cpu_down+0x5c/0xa0 cpu_subsys_offline+0x24/0x40 device_offline+0xf0/0x130 dlpar_offline_cpu+0x1c4/0x2a0 dlpar_cpu_remove+0xb8/0x190 dlpar_cpu_remove_by_index+0x12c/0x150 dlpar_cpu+0x94/0x800 pseries_hp_work_fn+0x128/0x1e0 process_one_work+0x304/0x5d0 worker_thread+0xcc/0x7a0 kthread+0x1ac/0x1c0 ret_from_kernel_thread+0x5c/0x80 The latter trace is due to the following sequence: page_alloc_cpu_dead drain_pages drain_pages_zone free_pcppages_bulk where drain_pages() in this case is called under the assumption that the unplugged cpu is no longer executing. To ensure that is the case, and early call is made to __cpu_die()->pseries_cpu_die(), which runs a loop that waits for the cpu to reach a halted state by polling its status via query-cpu-stopped-state RTAS calls. It only polls for 25 iterations before giving up, however, and in the trace above this results in the following being printed only .1 seconds after the hotplug worker thread begins processing the unplug request: pseries-hotplug-cpu: Attempting to remove CPU , drc index: 1000013a Querying DEAD? cpu 314 (314) shows 2 At that point the worker thread assumes the unplugged CPU is in some unknown/dead state and procedes with the cleanup, causing the race with the XIVE cleanup code executed by the unplugged CPU. Fix this by waiting indefinitely, but also making an effort to avoid spurious lockup messages by allowing for rescheduling after polling the CPU status and printing a warning if we wait for longer than 120s. Fixes: eac1e731b59ee ("powerpc/xive: guest exploitation of the XIVE interrupt controller") Suggested-by: Michael Ellerman Signed-off-by: Michael Roth Tested-by: Greg Kurz Reviewed-by: Thiago Jung Bauermann Reviewed-by: Greg Kurz [mpe: Trim oopses in change log slightly for readability] Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200811161544.10513-1-mdroth@linux.vnet.ibm.com Signed-off-by: Sasha Levin

pseries: Fix 64 bit logical memory block panic

2020-08-21T11:07:29Z

commit 89c140bbaeee7a55ed0360a88f294ead2b95201b upstream. Booting with a 4GB LMB size causes us to panic: qemu-system-ppc64: OS terminated: OS panic: Memory block size not suitable: 0x0 Fix pseries_memory_block_size() to handle 64 bit LMBs. Cc: stable@vger.kernel.org Signed-off-by: Anton Blanchard Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200715000820.1255764-1-anton@ozlabs.org Signed-off-by: Greg Kroah-Hartman

powerpc/pseries/hotplug-cpu: Remove double free in error path

2020-08-19T06:24:03Z

[ Upstream commit a0ff72f9f5a780341e7ff5e9ba50a0dad5fa1980 ] In the unlikely event that the device tree lacks a /cpus node, find_dlpar_cpus_to_add() oddly frees the cpu_drcs buffer it has been passed before returning an error. Its only caller also frees the buffer on error. Remove the less conventional kfree() of a caller-supplied buffer from find_dlpar_cpus_to_add(). Fixes: 90edf184b9b7 ("powerpc/pseries: Add CPU dlpar add functionality") Signed-off-by: Nathan Lynch Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20190919231633.1344-1-nathanl@linux.ibm.com Signed-off-by: Sasha Levin

powerpc/rtas: don't online CPUs for partition suspend

2020-08-19T06:23:54Z

[ Upstream commit ec2fc2a9e9bbad9023aab65bc472ce7a3ca8608f ] Partition suspension, used for hibernation and migration, requires that the OS place all but one of the LPAR's processor threads into one of two states prior to calling the ibm,suspend-me RTAS function: * the architected offline state (via RTAS stop-self); or * the H_JOIN hcall, which does not return until the partition resumes execution Using H_CEDE as the offline mode, introduced by commit 3aa565f53c39 ("powerpc/pseries: Add hooks to put the CPU into an appropriate offline state"), means that any threads which are offline from Linux's point of view must be moved to one of those two states before a partition suspension can proceed. This was eventually addressed in commit 120496ac2d2d ("powerpc: Bring all threads online prior to migration/hibernation"), which added code to temporarily bring up any offline processor threads so they can call H_JOIN. Conceptually this is fine, but the implementation has had multiple races with cpu hotplug operations initiated from user space[1][2][3], the error handling is fragile, and it generates user-visible cpu hotplug events which is a lot of noise for a platform feature that's supposed to minimize disruption to workloads. With commit 3aa565f53c39 ("powerpc/pseries: Add hooks to put the CPU into an appropriate offline state") reverted, this code becomes unnecessary, so remove it. Since any offline CPUs now are truly offline from the platform's point of view, it is no longer necessary to bring up CPUs only to have them call H_JOIN and then go offline again upon resuming. Only active threads are required to call H_JOIN; stopped threads can be left alone. [1] commit a6717c01ddc2 ("powerpc/rtas: use device model APIs and serialization during LPM") [2] commit 9fb603050ffd ("powerpc/rtas: retry when cpu offline races with suspend/migration") [3] commit dfd718a2ed1f ("powerpc/rtas: Fix a potential race between CPU-Offline & Migration") Fixes: 120496ac2d2d ("powerpc: Bring all threads online prior to migration/hibernation") Signed-off-by: Nathan Lynch Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200612051238.1007764-3-nathanl@linux.ibm.com Signed-off-by: Sasha Levin

powerpc/pseries: remove cede offline state for CPUs

2020-08-19T06:23:54Z

[ Upstream commit 48f6e7f6d948b56489da027bc3284c709b939d28 ] This effectively reverts commit 3aa565f53c39 ("powerpc/pseries: Add hooks to put the CPU into an appropriate offline state"), which added an offline mode for CPUs which uses the H_CEDE hcall instead of the architected stop-self RTAS function in order to facilitate "folding" of dedicated mode processors on PowerVM platforms to achieve energy savings. This has been the default offline mode since its introduction. There's nothing about stop-self that would prevent the hypervisor from achieving the energy savings available via H_CEDE, so the original premise of this change appears to be flawed. I also have encountered the claim that the transition to and from ceded state is much faster than stop-self/start-cpu. Certainly we would not want to use stop-self as an *idle* mode. That is what H_CEDE is for. However, this difference is insignificant in the context of Linux CPU hotplug, where the latency of an offline or online operation on current systems is on the order of 100ms, mainly attributable to all the various subsystems' cpuhp callbacks. The cede offline mode also prevents accurate accounting, as discussed before: https://lore.kernel.org/linuxppc-dev/1571740391-3251-1-git-send-email-ego@linux.vnet.ibm.com/ Unconditionally use stop-self to offline processor threads. This is the architected method for offlining CPUs on PAPR systems. The "cede_offline" boot parameter is rendered obsolete. Removing this code enables the removal of the partition suspend code which temporarily onlines all present CPUs. Fixes: 3aa565f53c39 ("powerpc/pseries: Add hooks to put the CPU into an appropriate offline state") Signed-off-by: Nathan Lynch Reviewed-by: Gautham R. Shenoy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200612051238.1007764-2-nathanl@linux.ibm.com Signed-off-by: Sasha Levin

powerpc/4xx: Don't unmap NULL mbase

2020-06-24T15:48:59Z

[ Upstream commit bcec081ecc940fc38730b29c743bbee661164161 ] Signed-off-by: huhai Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200521072648.1254699-1-mpe@ellerman.id.au Signed-off-by: Sasha Levin

powerpc/8xx: Drop CONFIG_8xx_COPYBACK option

2020-06-24T15:48:56Z

[ Upstream commit d3efcd38c0b99162d889e36a30425345a18edb33 ] CONFIG_8xx_COPYBACK was there to help disabling copyback cache mode for debuging hardware. But nobody will design new boards with 8xx now. All 8xx platforms select it, so make it the default and remove the option. Also remove the Mx_RESETVAL values which are pretty useless and hide the real value while reading code. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/bcc968cda075516eb76e2f25e09821f582c566b4.1589866984.git.christophe.leroy@csgroup.eu Signed-off-by: Sasha Levin

powerpc/powernv: add NULL check after kzalloc

2020-06-24T15:48:52Z

[ Upstream commit ceffa63acce7165c442395b7d64a11ab8b5c5dca ] Fixes coccicheck warning: ./arch/powerpc/platforms/powernv/opal.c:813:1-5: alloc with no test, possible model on line 814 Add NULL check after kzalloc. Signed-off-by: Chen Zhou Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200509020838.121660-1-chenzhou10@huawei.com Signed-off-by: Sasha Levin

powerpc/ps3: Fix kexec shutdown hang

2020-06-24T15:48:49Z

[ Upstream commit 126554465d93b10662742128918a5fc338cda4aa ] The ps3_mm_region_destroy() and ps3_mm_vas_destroy() routines are called very late in the shutdown via kexec's mmu_cleanup_all routine. By the time mmu_cleanup_all runs it is too late to use udbg_printf, and calling it will cause PS3 systems to hang. Remove all debugging statements from ps3_mm_region_destroy() and ps3_mm_vas_destroy() and replace any error reporting with calls to lv1_panic. With this change builds with 'DEBUG' defined will not cause kexec reboots to hang, and builds with 'DEBUG' defined or not will end in lv1_panic if an error is encountered. Signed-off-by: Geoff Levand Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/7325c4af2b4c989c19d6a26b90b1fec9c0615ddf.1589049250.git.geoff@infradead.org Signed-off-by: Sasha Levin