doc: skiboot-5.7-rc2 release notes

Signed-off-by: Stewart Smith <[email protected]>

doc/release-notes/skiboot-5.7-rc2.rst

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+.. _skiboot-5.7-rc2:
+
+skiboot-5.7-rc2
+===============
+
+skiboot v5.7-rc2 was released on Thursday July 13th 2017. It is the second
+release candidate of skiboot 5.7, which will become the new stable release
+of skiboot following the 5.6 release, first released 24th May 2017.
+
+skiboot v5.7-rc2 contains all bug fixes as of :ref:`skiboot-5.4.6`
+and :ref:`skiboot-5.1.19` (the currently maintained stable releases). We
+do not currently expect to do any 5.6.x stable releases.
+
+For how the skiboot stable releases work, see :ref:`stable-rules` for details.
+
+The current plan is to cut the final 5.7 in the next week or so, with skiboot
+5.7 being for all POWER8 and POWER9 platforms in op-build v1.18
+(due July 12th, but will come *after* skiboot 5.7).
+
+This is the second release using the new regular six week release cycle,
+similar to op-build, but slightly offset to allow for a short stabilisation
+period. Expected release dates and contents are tracked using GitHub milestone
+and issues: https://github.com/open-power/skiboot/milestones
+
+Over :ref:`skiboot-5.7-rc1`, we have the following changes:
+
+POWER9
+------
+
+There are many important changes for POWER9 DD1 and DD2 systems. POWER9 support
+should be considered in development and skiboot 5.7 is certainly **NOT**
+suitable for POWER9 production environments.
+
+- HDAT: Add IPMI sensor data under /bmc node
+- numa/associativity: Add a new level of NUMA for GPU's
+
+  Today we have an issue where the NUMA nodes corresponding
+  to GPU's have the same affinity/distance as normal memory
+  nodes. Our reference-points today supports two levels
+  [0x4, 0x4] for normal systems and [0x4, 0x3] for Power8E
+  systems. This patch adds a new level [0x4, X, 0x2] and
+  uses node-id as at all levels for the GPU.
+- xive: Enable memory backing of queues
+
+  This dedicates 6x64k pages of memory permanently for the XIVE to
+  use for internal queue overflow. This allows the XIVE to deal with
+  some corner cases where the internal queues might prove insufficient.
+
+- xive: Properly get rid of donated indirect pages during reset
+
+  Otherwise they keep being used accross kexec causing memory
+  corruption in subsequent kernels once KVM has been used.
+
+- cpu: Better handle unknown flags in opal_reinit_cpus()
+
+  At the moment, if we get passed flags we don't know about, we
+  return OPAL_UNSUPPORTED but we still perform whatever actions
+  was requied by the flags we do support. Additionally, on P8,
+  we attempt a SLW re-init which hasn't been supported since
+  Murano DD2.0 and will crash your system.
+
+  It's too late to fix on existing systems so Linux will have to
+  be careful at least on P8, but to avoid future issues let's clean
+  that up, make sure we only use slw_reinit() when HILE isn't
+  supported.
+- cpu: Unconditionally cleanup TLBs on P9 in opal_reinit_cpus()
+
+  This can work around problems where Linux fails to properly
+  cleanup part or all of the TLB on kexec.
+
+- Fix scom addresses for power9 nx checkstop hmi handling.
+
+  Scom addresses for NX status, DMA & ENGINE FIR and PBI FIR has changed
+  for Power9. Fixup thoes while handling nx checkstop for Power9.
+- Fix scom addresses for power9 core checkstop hmi handling.
+
+  Scom addresses for CORE FIR (Fault Isolation Register) and Malfunction
+  Alert Register has changed for Power9. Fixup those while handling core
+  checkstop for Power9.
+
+  Without this change HMI handler fails to check for correct reason for
+  core checkstop on Power9.
+
+- core/mem_region: check return value of add_region
+
+  The only sensible thing to do if this fails is to abort() as we've
+  likely just failed reserving reserved memory regions, and nothing
+  good comes from that.
+
+PHB4
+^^^^
+- phb4: Do more retries on link training failures
+  Currently we only retry once when we have a link training failure.
+  This changes this to be 3 retries as 1 retry is not giving us enough
+  reliablity.
+
+  This will increase the boot time, especially on systems where we
+  incorrectly detect a link presence when there really is nothing
+  present. I'll post a followup patch to optimise our timings to help
+  mitigate this later.
+
+- phb4: Workaround phy lockup by doing full PHB reset on retry
+
+  For PHB4 it's possible that the phy may end up in a bad state where it
+  can no longer recieve data. This can manifest as the link not
+  retraining. A simple PERST will not clear this. The PHB must be
+  completely reset.
+
+  This changes the retry state to CRESET to do this.
+
+  This issue may also manifest itself as the link training in a degraded
+  state (lower speed or narrower width). This patch doesn't attempt to
+  fix that (will come later).
+- pci: Add ability to trace timing
+
+  PCI link training is responsible for a huge chunk of the skiboot boot
+  time, so add the ability to trace it waiting in the main state
+  machine.
+- pci: Print resetting PHB notice at higher log level
+
+  Currently during boot there a long delay while we wait for the PHBs to
+  be reset and train. During this time, there is no output from skiboot
+  and the last message doesn't give an indication of what's happening.
+
+  This boosts the PHB reset message from info to notice so users can see
+  what's happening during this long period of waiting.
+- phb4: Only set one bit in nfir
+
+  The MPIPL procedure says to only set bit 26 when forcing the PEC into
+  freeze mode. Currently we set bits 24-27.
+
+  This changes the code to follow spec and only set bit 26.
+- phb4: Fix order of pfir/nfir clearing in CRESET
+
+  According to the workbook, pfir must be cleared before the nfir.
+  The way we have it now causes the nfir to not clear properly in some
+  error circumstances.
+
+  This swaps the order to match the workbook.
+- phb4: Remove incorrect state transition
+
+  When waiting in PHB4_SLOT_CRESET_WAIT_CQ for transations to end, we
+  incorrectly move onto the next state.  Generally we don't hit this as
+  the transactions have ended already anyway.
+
+  This removes the incorrect state transition.
+- phb4: Set default lane equalisation
+
+  Set default lane equalisation if there is nothing in the device-tree.
+
+  Default value taken from hdat and confirmed by hardware team. Neatens
+  the code up a bit too.
+- hdata: Fix phb4 lane-eq property generation
+
+  The lane-eq data we get from hdat is all 7s but what we end up in the
+  device tree is: ::
+
+    xscom@603fc00000000/pbcq@4010c00/stack@0/ibm,lane-eq
+                     00000000 31c339e0 00000000 0000000c
+                     00000000 00000000 00000000 00000000
+                     00000000 31c30000 77777777 77777777
+                     77777777 77777777 77777777 77777777
+
+  This fixes grabbing the properties from hdat and fixes the call to put
+  them in the device tree.
+- phb4: Fix PHB4 fence recovery.
+
+  We had a few problems:
+
+  - We used the wrong register to trigger the reset (spec bug)
+  - We should clear the PFIR and NFIR while the reset is asserted
+  - ... and in the right order !
+  - We should only apply the DD1 workaround after the reset has
+    been lifted.
+  - We should ensure we use ASB whenever we are fenced or doing a
+    CRESET
+  - Make config ops write with ASB
+- phb4: Verbose EEH options
+
+  Enabled via nvram pci-eeh-verbose=true. ie. ::
+
+    nvram -p ibm,skiboot --update-config pci-eeh-verbose=true
+- phb4: Print more info when PHB fences
+
+  For now at PHBERR level. We don't have room in the diags data
+  passed to Linux for these unfortunately.
+
+
+Testing/development
+-------------------
+- lpc: remove double LPC prefix from messages
+- opal-ci/fetch-debian-jessie-installer: follow redirects
+  Fixes some CI failures
+- test/qemu-jessie: bail out fast on kernel panic
+- test/qemu-jessie: dump boot log on failure
+- travis: add fedora26
+- xz: add fallthrough annotations to silence GCC7 warning