skiboot v6.0.20 release notesv6.0.20

Signed-off-by: Vasant Hegde <hegdevasant@linux.vnet.ibm.com>

1 files changed, 204 insertions, 0 deletions

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+.. _skiboot-6.0.20:
+
+==============
+skiboot-6.0.20
+==============
+
+skiboot 6.0.20 was released on Thursday May 9th, 2019. It replaces
+:ref:`skiboot-6.0.19` as the current stable release in the 6.0.x series.
+
+It is recommended that 6.0.20 be used instead of any previous 6.0.x version
+due to the bug fixes it contains.
+
+Bug fixes included in this release are:
+
+- core/flash: Retry requests as necessary in flash_load_resource()
+
+  We would like to successfully boot if we have a dependency on the BMC
+  for flash even if the BMC is not current ready to service flash
+  requests. On the assumption that it will become ready, retry for several
+  minutes to cover a BMC reboot cycle and *eventually* rather than
+  *immediately* crash out with:
+
+      [  269.549748] reboot: Restarting system
+      [  390.297462587,5] OPAL: Reboot request...
+      [  390.297737995,5] RESET: Initiating fast reboot 1...
+      [  391.074707590,5] Clearing unused memory:
+      [  391.075198880,5] PCI: Clearing all devices...
+      [  391.075201618,7] Clearing region 201ffe000000-201fff800000
+      [  391.086235699,5] PCI: Resetting PHBs and training links...
+      [  391.254089525,3] FFS: Error 17 reading flash header
+      [  391.254159668,3] FLASH: Can't open ffs handle: 17
+      [  392.307245135,5] PCI: Probing slots...
+      [  392.363723191,5] PCI Summary:
+      ...
+      [  393.423255262,5] OCC: All Chip Rdy after 0 ms
+      [  393.453092828,5] INIT: Starting kernel at 0x20000000, fdt at
+      0x30800a88 390645 bytes
+      [  393.453202605,0] FATAL: Kernel is zeros, can't execute!
+      [  393.453247064,0] Assert fail: core/init.c:593:0
+      [  393.453289682,0] Aborting!
+      CPU 0040 Backtrace:
+       S: 0000000031e03ca0 R: 000000003001af60   ._abort+0x4c
+       S: 0000000031e03d20 R: 000000003001afdc   .assert_fail+0x34
+       S: 0000000031e03da0 R: 00000000300146d8   .load_and_boot_kernel+0xb30
+       S: 0000000031e03e70 R: 0000000030026cf0   .fast_reboot_entry+0x39c
+       S: 0000000031e03f00 R: 0000000030002a4c   fast_reset_entry+0x2c
+       --- OPAL boot ---
+
+  The OPAL flash API hooks directly into the blocklevel layer, so there's
+  no delay for e.g. the host kernel, just for asynchronously loaded
+  resources during boot.
+
+- pci/iov: Remove skiboot VF tracking
+
+  This feature was added a few years ago in response to a request to make
+  the MaxPayloadSize (MPS) field of a Virtual Function match the MPS of the
+  Physical Function that hosts it.
+
+  The SR-IOV specification states the the MPS field of the VF is "ResvP".
+  This indicates the VF will use whatever MPS is configured on the PF and
+  that the field should be treated as a reserved field in the config space
+  of the VF. In other words, a SR-IOV spec compliant VF should always return
+  zero in the MPS field.  Adding hacks in OPAL to make it non-zero is...
+  misguided at best.
+
+  Additionally, there is a bug in the way pci_device structures are handled
+  by VFs that results in a crash on fast-reboot that occurs if VFs are
+  enabled and then disabled prior to rebooting. This patch fixes the bug by
+  removing the code entirely. This patch has no impact on SR-IOV support on
+  the host operating system.
+
+- hw/xscom: Enable sw xstop by default on p9
+
+  This was disabled at some point during bringup to make life easier for
+  the lab folks trying to debug NVLink issues. This hack really should
+  have never made it out into the wild though, so we now have the
+  following situation occuring in the field:
+
+   1) A bad happens
+   2) The host kernel recieves an unrecoverable HMI and calls into OPAL to
+      request a platform reboot.
+   3) OPAL rejects the reboot attempt and returns to the kernel with
+      OPAL_PARAMETER.
+   4) Kernel panics and attempts to kexec into a kdump kernel.
+
+  A side effect of the HMI seems to be CPUs becoming stuck which results
+  in the initialisation of the kdump kernel taking a extremely long time
+  (6+ hours). It's also been observed that after performing a dump the
+  kdump kernel then crashes itself because OPAL has ended up in a bad
+  state as a side effect of the HMI.
+
+  All up, it's not very good so re-enable the software checkstop by
+  default. If people still want to turn it off they can using the nvram
+  override.
+
+- opal/hmi: Initialize the hmi event with old value of TFMR.
+
+  Do this before we fix TFAC errors. Otherwise the event at host console
+  shows no thread error reported in TFMR register.
+
+  Without this patch the console event show TFMR with no thread error:
+  (DEC parity error TFMR[59] injection)
+
+  [   53.737572] Severe Hypervisor Maintenance interrupt [Recovered]
+  [   53.737596]  Error detail: Timer facility experienced an error
+  [   53.737611]  HMER: 0840000000000000
+  [   53.737621]  TFMR: 3212000870e04000
+
+  After this patch it shows old TFMR value on host console:
+
+  [ 2302.267271] Severe Hypervisor Maintenance interrupt [Recovered]
+  [ 2302.267305]  Error detail: Timer facility experienced an error
+  [ 2302.267320]  HMER: 0840000000000000
+  [ 2302.267330]  TFMR: 3212000870e14010
+
+- libflash/ipmi-hiomap: Fix blocks count issue
+
+  We convert data size to block count and pass block count to BMC.
+  If data size is not block aligned then we endup sending block count
+  less than actual data. BMC will write partial data to flash memory.
+
+  Sample log :
+  [  594.388458416,7] HIOMAP: Marked flash dirty at 0x42010 for 8
+  [  594.398756487,7] HIOMAP: Flushed writes
+  [  594.409596439,7] HIOMAP: Marked flash dirty at 0x42018 for 3970
+  [  594.419897507,7] HIOMAP: Flushed writes
+
+  In this case HIOMAP sent data with block count=0 and hence BMC didn't
+  flush data to flash.
+
+  Lets fix this issue by adjusting block count before sending it to BMC.
+
+- Fix hang in pnv_platform_error_reboot path due to TOD failure.
+
+  On TOD failure, with TB stuck, when linux heads down to
+  pnv_platform_error_reboot() path due to unrecoverable hmi event, the panic
+  cpu gets stuck in OPAL inside ipmi_queue_msg_sync(). At this time, rest
+  all other cpus are in smp_handle_nmi_ipi() waiting for panic cpu to proceed.
+  But with panic cpu stuck inside OPAL, linux never recovers/reboot.
+
+  p0 c1 t0
+  NIA : 0x000000003001dd3c <.time_wait+0x64>
+  CFAR : 0x000000003001dce4 <.time_wait+0xc>
+  MSR : 0x9000000002803002
+  LR : 0x000000003002ecf8 <.ipmi_queue_msg_sync+0xec>
+
+  STACK: SP NIA
+  0x0000000031c236e0 0x0000000031c23760 (big-endian)
+  0x0000000031c23760 0x000000003002ecf8 <.ipmi_queue_msg_sync+0xec>
+  0x0000000031c237f0 0x00000000300aa5f8 <.hiomap_queue_msg_sync+0x7c>
+  0x0000000031c23880 0x00000000300aaadc <.hiomap_window_move+0x150>
+  0x0000000031c23950 0x00000000300ab1d8 <.ipmi_hiomap_write+0xcc>
+  0x0000000031c23a90 0x00000000300a7b18 <.blocklevel_raw_write+0xbc>
+  0x0000000031c23b30 0x00000000300a7c34 <.blocklevel_write+0xfc>
+  0x0000000031c23bf0 0x0000000030030be0 <.flash_nvram_write+0xd4>
+  0x0000000031c23c90 0x000000003002c128 <.opal_write_nvram+0xd0>
+  0x0000000031c23d20 0x00000000300051e4 <opal_entry+0x134>
+  0xc000001fea6e7870 0xc0000000000a9060 <opal_nvram_write+0x80>
+  0xc000001fea6e78c0 0xc000000000030b84 <nvram_write_os_partition+0x94>
+  0xc000001fea6e7960 0xc0000000000310b0 <nvram_pstore_write+0xb0>
+  0xc000001fea6e7990 0xc0000000004792d4 <pstore_dump+0x1d4>
+  0xc000001fea6e7ad0 0xc00000000018a570 <kmsg_dump+0x140>
+  0xc000001fea6e7b40 0xc000000000028e5c <panic_flush_kmsg_end+0x2c>
+  0xc000001fea6e7b60 0xc0000000000a7168 <pnv_platform_error_reboot+0x68>
+  0xc000001fea6e7bd0 0xc0000000000ac9b8 <hmi_event_handler+0x1d8>
+  0xc000001fea6e7c80 0xc00000000012d6c8 <process_one_work+0x1b8>
+  0xc000001fea6e7d20 0xc00000000012da28 <worker_thread+0x88>
+  0xc000001fea6e7db0 0xc0000000001366f4 <kthread+0x164>
+  0xc000001fea6e7e20 0xc00000000000b65c <ret_from_kernel_thread+0x5c>
+
+  This is because, there is a while loop towards the end of
+  ipmi_queue_msg_sync() which keeps looping until "sync_msg" does not match
+  with "msg". It loops over time_wait_ms() until exit condition is met. In
+  normal scenario time_wait_ms() calls run pollers so that ipmi backend gets
+  a chance to check ipmi response and set sync_msg to NULL.
+
+          while (sync_msg == msg)
+                  time_wait_ms(10);
+
+  But in the event when TB is in failed state time_wait_ms()->time_wait_poll()
+  returns immediately without calling pollers and hence we end up looping
+  forever. This patch fixes this hang by calling opal_run_pollers() in TB
+  failed state as well.
+
+- core/ipmi: Print correct netfn value
+
+- core/lock: don't set bust_locks on lock error
+
+  bust_locks is a big hammer that guarantees a mess if it's set while
+  all other threads are not stopped.
+
+  I propose removing this in the lock error paths. In debugging the
+  previous deadlock false positive, none of the error messages printed,
+  and the in-memory console was totally garbled due to lack of locking.
+
+  I think it's generally better for debugging and system integrity to
+  keep locks held when lock errors occur. Lock busting should be used
+  carefully, just to allow messages to be printed out or machine to be
+  restarted, probably when the whole system is single-threaded.
+
+  Skiboot is slowly working toward that being feasible with co-operative
+  debug APIs between firmware and host, but for the time being,
+  difficult lock crashes are better not to corrupt everything by
+  busting locks.