| .. _skiboot-5.9-rc2: |
| |
| skiboot-5.9-rc2 |
| =============== |
| |
| skiboot v5.9-rc2 was released on Monday October 16th 2017. It is the second |
| release candidate of skiboot 5.9, which will become the new stable release |
| of skiboot following the 5.8 release, first released August 31st 2017. |
| |
| skiboot v5.9-rc2 contains all bug fixes as of :ref:`skiboot-5.4.8` |
| and :ref:`skiboot-5.1.21` (the currently maintained stable releases). We |
| do not currently expect to do any 5.8.x stable releases. |
| |
| For how the skiboot stable releases work, see :ref:`stable-rules` for details. |
| |
| The current plan is to cut the final 5.9 by October 17th, with skiboot 5.9 |
| being for all POWER8 and POWER9 platforms in op-build v1.20 (Due October 18th). |
| This release will be targetted to early POWER9 systems. |
| |
| Over :ref:`skiboot-5.9-rc1`, we have the following changes: |
| |
| - opal-prd: Fix memory leak |
| - hdata/i2c: update the list of known i2c devs |
| |
| This updates the list of known i2c devices - as of HDAT spec v10.5e - so |
| that they can be properly identified during the hdat parsing. |
| - hdata/i2c: log unknown i2c devices |
| |
| An i2c device is unknown if either the i2c device list is outdated or |
| the device is marked as unknown (0xFF) in the hdat. |
| |
| - opal/cpu: Mark the core as bad while disabling threads of the core. |
| |
| If any of the core fails to sync its TB during chipTOD initialization, |
| all the threads of that core are disabled. But this does not make |
| linux kernel to ignore the core/cpus. It crashes while bringing them up |
| with below backtrace: :: |
| |
| [ 38.883898] kexec_core: Starting new kernel |
| cpu 0x0: Vector: 300 (Data Access) at [c0000003f277b730] |
| pc: c0000000001b9890: internal_create_group+0x30/0x304 |
| lr: c0000000001b9880: internal_create_group+0x20/0x304 |
| sp: c0000003f277b9b0 |
| msr: 900000000280b033 |
| dar: 40 |
| dsisr: 40000000 |
| current = 0xc0000003f9f41000 |
| paca = 0xc00000000fe00000 softe: 0 irq_happened: 0x01 |
| pid = 2572, comm = kexec |
| Linux version 4.13.2-openpower1 (jenkins@p89) (gcc version 6.4.0 (Buildroot 2017.08-00006-g319c6e1)) #1 SMP Wed Sep 20 05:42:11 UTC 2017 |
| enter ? for help |
| [c0000003f277b9b0] c0000000008a8780 (unreliable) |
| [c0000003f277ba50] c00000000041c3ac topology_add_dev+0x2c/0x40 |
| [c0000003f277ba70] c00000000006b078 cpuhp_invoke_callback+0x88/0x170 |
| [c0000003f277bac0] c00000000006b22c cpuhp_up_callbacks+0x54/0xb8 |
| [c0000003f277bb10] c00000000006bc68 cpu_up+0x11c/0x168 |
| [c0000003f277bbc0] c00000000002f0e0 default_machine_kexec+0x1fc/0x274 |
| [c0000003f277bc50] c00000000002e2d8 machine_kexec+0x50/0x58 |
| [c0000003f277bc70] c0000000000de4e8 kernel_kexec+0x98/0xb4 |
| [c0000003f277bce0] c00000000008b0f0 SyS_reboot+0x1c8/0x1f4 |
| [c0000003f277be30] c00000000000b118 system_call+0x58/0x6c |
| |
| - hw/imc: pause microcode at boot |
| |
| IMC nest counters has both in-band (ucode access) and out of |
| band access to it. Since not all nest counter configurations |
| are supported by ucode, out of band tools are used to characterize |
| other configuration. |
| |
| So it is prefer to pause the nest microcode at boot to aid the |
| nest out of band tools. If the ucode not paused and OS does not |
| have IMC driver support, then out to band tools will race with |
| ucode and end up getting undesirable values. Patch to check and |
| pause the ucode at boot. |
| |
| OPAL provides APIs to control IMC counters. OPAL_IMC_COUNTERS_INIT |
| is used to initialize these counters at boot. OPAL_IMC_COUNTERS_START |
| and OPAL_IMC_COUNTERS_STOP API calls should be used to start and pause |
| these IMC engines. `doc/opal-api/opal-imc-counters.rst` details the |
| OPAL APIs and their usage. |
| - xive: Fix VP free block group mode false-positive parameter check |
| |
| The check to ensure the buddy allocation idx is aligned to its |
| allocation order was not taking into account the allocation split. |
| This would result in opal_xive_free_vp_block failures despite |
| giving the same value as returned by opal_xive_alloc_vp_block. |
| |
| E.g., starting then stopping 4 KVM guests gives the following pattern |
| in the host: :: |
| |
| opal_xive_alloc_vp_block(5)=0x45000020 |
| opal_xive_alloc_vp_block(5)=0x45000040 |
| opal_xive_alloc_vp_block(5)=0x45000060 |
| opal_xive_alloc_vp_block(5)=0x45000080 |
| opal_xive_free_vp_block(0x45000020)=-1 |
| opal_xive_free_vp_block(0x45000040)=0 |
| opal_xive_free_vp_block(0x45000060)=-1 |
| opal_xive_free_vp_block(0x45000080)=0 |
| - hw/p8-i2c: Fix deadlock in p9_i2c_bus_owner_change |
| |
| When debugging a system where Linux was taking soft lockup errors with |
| two CPUs stuck in OPAL: |
| |
| ======================= ============== |
| CPU0 CPU1 |
| ======================= ============== |
| lock |
| p8_i2c_recover |
| opal_handle_interrupt |
| sync_timer |
| cancel_timer |
| p9_i2c_bus_owner_change |
| occ_p9_interrupt |
| xive_source_interrupt |
| opal_handle_interrupt |
| ======================= ============== |
| |
| p8_i2c_recover() is a timer, and is stuck trying to take master->lock. |
| p9_i2c_bus_owner_change() has taken master->lock, but then is stuck waiting |
| for all timers to complete. We deadlock. |
| |
| Fix this by using cancel_timer_async(). |
| |
| - FSP/CONSOLE: Limit number of error logging |
| |
| Commit c8a7535f (FSP/CONSOLE: Workaround for unresponsive ipmi daemon) added |
| error logging when buffer is full. In some corner cases kernel may call this |
| function multiple time and we may endup logging error again and again. |
| |
| This patch fixes it by generating error log only once. |
| |
| - FSP/CONSOLE: Fix fsp_console_write_buffer_space() call |
| |
| Kernel calls fsp_console_write_buffer_space() to check console buffer space |
| availability. If there is enough buffer space to write data, then kernel will |
| call fsp_console_write() to write actual data. |
| |
| In some extreme corner cases (like one explained in commit c8a7535f) |
| console becomes full and this function returns 0 to kernel (or space available |
| in console buffer < next incoming data size). Kernel will continue retrying |
| until it gets enough space. So we will start seeing RCU stalls. |
| |
| This patch keeps track of previous available space. If previous space is same |
| as current means not enough space in console buffer to write incoming data. |
| It may be due to very high console write operation and slow response from FSP |
| -OR- FSP has stopped processing data (ex: because of ipmi daemon died). At this |
| point we will start timer with timeout of SER_BUFFER_OUT_TIMEOUT (10 secs). |
| If situation is not improved within 10 seconds means something went bad. Lets |
| return OPAL_RESOURCE so that kernel can drop console write and continue. |
| - FSP/CONSOLE: Close SOL session during R/R |
| |
| Presently we are not closing SOL and FW console sessions during R/R. Host will |
| continue to write to SOL buffer during FSP R/R. If there is heavy console write |
| operation happening during FSP R/R (like running `top` command inside console), |
| then at some point console buffer becomes full. fsp_console_write_buffer_space() |
| returns 0 (or less than required space to write data) to host. While one thread |
| is busy writing to console, if some other threads tries to write data to console |
| we may see RCU stalls (like below) in kernel. :: |
| |
| [ 2082.828363] INFO: rcu_sched detected stalls on CPUs/tasks: { 32} (detected by 16, t=6002 jiffies, g=23154, c=23153, q=254769) |
| [ 2082.828365] Task dump for CPU 32: |
| [ 2082.828368] kworker/32:3 R running task 0 4637 2 0x00000884 |
| [ 2082.828375] Workqueue: events dump_work_fn |
| [ 2082.828376] Call Trace: |
| [ 2082.828382] [c000000f1633fa00] [c00000000013b6b0] console_unlock+0x570/0x600 (unreliable) |
| [ 2082.828384] [c000000f1633fae0] [c00000000013ba34] vprintk_emit+0x2f4/0x5c0 |
| [ 2082.828389] [c000000f1633fb60] [c00000000099e644] printk+0x84/0x98 |
| [ 2082.828391] [c000000f1633fb90] [c0000000000851a8] dump_work_fn+0x238/0x250 |
| [ 2082.828394] [c000000f1633fc60] [c0000000000ecb98] process_one_work+0x198/0x4b0 |
| [ 2082.828396] [c000000f1633fcf0] [c0000000000ed3dc] worker_thread+0x18c/0x5a0 |
| [ 2082.828399] [c000000f1633fd80] [c0000000000f4650] kthread+0x110/0x130 |
| [ 2082.828403] [c000000f1633fe30] [c000000000009674] ret_from_kernel_thread+0x5c/0x68 |
| |
| Hence lets close SOL (and FW console) during FSP R/R. |
| - FSP/CONSOLE: Do not associate unavailable console |
| |
| Presently OPAL sends associate/unassociate MBOX command for all |
| FSP serial console (like below OPAL message). We have to check |
| console is available or not before sending this message. :: |
| |
| [ 5013.227994012,7] FSP: Reassociating HVSI console 1 |
| [ 5013.227997540,7] FSP: Reassociating HVSI console 2 |
| - FSP: Disable PSI link whenever FSP tells OPAL about impending R/R |
| |
| Commit 42d5d047 fixed scenario where DPO has been initiated, but FSP went |
| into reset before the CEC power down came in. But this is generic issue |
| that can happen in normal shutdown path as well. |
| |
| Hence disable PSI link as soon as we detect FSP impending R/R. |
| |
| - fsp: return OPAL_BUSY_EVENT on failure sending FSP_CMD_POWERDOWN_NORM |
| Also, return OPAL_BUSY_EVENT on failure sending FSP_CMD_REBOOT / DEEP_REBOOT. |
| |
| We had a race condition between FSP Reset/Reload and powering down |
| the system from the host: |
| |
| Roughly: |
| |
| == ======================== ========================================================== |
| # FSP Host |
| == ======================== ========================================================== |
| 1 Power on |
| 2 Power on |
| 3 (inject EPOW) |
| 4 (trigger FSP R/R) |
| 5 Processes EPOW event, starts shutting down |
| 6 calls OPAL_CEC_POWER_DOWN |
| 7 (is still in R/R) |
| 8 gets OPAL_INTERNAL_ERROR, spins in opal_poll_events |
| 9 (FSP comes back) |
| 10 spinning in opal_poll_events |
| 11 (thinks host is running) |
| == ======================== ========================================================== |
| |
| The call to OPAL_CEC_POWER_DOWN is only made once as the reset/reload |
| error path for fsp_sync_msg() is to return -1, which means we give |
| the OS OPAL_INTERNAL_ERROR, which is fine, except that our own API |
| docs give us the opportunity to return OPAL_BUSY when trying again |
| later may be successful, and we're ambiguous as to if you should retry |
| on OPAL_INTERNAL_ERROR. |
| |
| For reference, the linux code looks like this: :: |
| |
| static void __noreturn pnv_power_off(void) |
| { |
| long rc = OPAL_BUSY; |
| |
| pnv_prepare_going_down(); |
| |
| while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) { |
| rc = opal_cec_power_down(0); |
| if (rc == OPAL_BUSY_EVENT) |
| opal_poll_events(NULL); |
| else |
| mdelay(10); |
| } |
| for (;;) |
| opal_poll_events(NULL); |
| } |
| |
| Which means that *practically* our only option is to return OPAL_BUSY |
| or OPAL_BUSY_EVENT. |
| |
| We choose OPAL_BUSY_EVENT for FSP systems as we do want to ensure we're |
| running pollers to communicate with the FSP and do the final bits of |
| Reset/Reload handling before we power off the system. |
