skiboot v5.10 was released on Friday February 23rd 2018. It is the first release of skiboot 5.10, and becomes the new stable release of skiboot following the 5.9 release, first released October 31st 2017.

skiboot v5.10 contains all bug fixes as of skiboot-5.9.8 and skiboot-5.4.9. We do not forsee any further 5.9.x releases.

For how the skiboot stable releases work, see Skiboot stable tree rules and releases for details.

Over skiboot-5.9, we have the following changes:

New Features

Since skiboot-5.10-rc3:

  • sensor-groups: occ: Add support to disable/enable sensor group

    This patch adds a new opal call to enable/disable a sensor group. This call is used to select the sensor groups that needs to be copied to main memory by OCC at runtime.

  • sensors: occ: Add energy counters

    Export the accumulated power values as energy sensors. The accumulator field of power sensors are used for representing energy counters which can be exported as energy counters in Linux hwmon interface.

  • sensors: Support reading u64 sensor values

    This patch adds support to read u64 sensor values. This also adds changes to the core and the backend implementation code to make this API as the base call. Host can use this new API to read sensors upto 64bits.

    This adds a list to store the pointer to the kernel u32 buffer, for older kernels making async sensor u32 reads.

  • dt: add /cpus/ibm,powerpc-cpu-features device tree bindings

    This is a new CPU feature advertising interface that is fine-grained, extensible, aware of privilege levels, and gives control of features to all levels of the stack (firmware, hypervisor, and OS).

    The design and binding specification is described in detail in doc/.

Since skiboot-5.10-rc2:

  • DT: Add “version” property under ibm, firmware-versions node

    First line of VERSION section in PNOR contains firmware version. Use that to add “version” property under firmware versions dt node.

    Sample output:

    root@xxx2:/proc/device-tree/ibm,firmware-versions# lsprop
    version          "witherspoon-ibm-OP9_v1.19_1.94"

Since skiboot-5.10-rc1:

  • hw/npu2: Implement logging HMI actions

Since skiboot-5.9:

  • hdata: Parse IPL FW feature settings

    Add parsing for the firmware feature flags in the HDAT. This indicates the settings of various parameters which are set at IPL time by firmware.

  • opal/xstop: Use nvram option to enable/disable sw checkstop.

    Add a mechanism to enable/disable sw checkstop by looking at nvram option opal-sw-xstop=<enable/disable>.

    For now this patch disables the sw checkstop trigger unless explicitly enabled through nvram option ‘opal-sw-xstop=enable’i for p9. This will allow an opportunity to get host kernel in panic path or xmon for unrecoverable HMIs or MCE, to be able to debug the issue effectively.

    To enable sw checkstop in opal issue following command:

    nvram -p ibm,skiboot --update-config opal-sw-xstop=enable

    NOTE: This is a workaround patch to disable sw checkstop by default to gain control in host kernel for better checkstop debugging. Once we have most of the checkstop issues stabilized/resolved, revisit this patch to enable sw checkstop by default.

    For p8 platform it will remain enabled by default unless explicitly disabled.

    To disable sw checkstop on p8 issue following command:

    nvram -p ibm,skiboot --update-config opal-sw-xstop=disable
  • hdata: Parse SPD data

    Parse SPD data and populate device tree.

    list of properties parsing from SPD:

    [root@ltc-wspoon dimm@d00f]# lsprop .
    memory-id        0000000c (12)      # DIMM type
    product-version  00000032 (50)      # Module Revision Code
    device_type      "memory-dimm-ddr4"
    serial-number    15d9acb6 (366587062)
    status           "okay"
    size             00004000 (16384)
    phandle          000000bd (189)
    ibm,loc-code     "UOPWR.0000000-Node0-DIMM7"
    part-number      "36ASF2G72PZ-2G6B2   "
    reg              0000d007 (53255)
    name             "dimm"
    manufacturer-id  0000802c (32812)  # Vendor ID, we can get vendor name from this ID

    Also update documentation.

  • hdata: Add memory hierarchy under xscom node

    We have memory to chip mapping but doesn’t have complete memory hierarchy. This patch adds memory hierarchy under xscom node. This is specific to P9 system as these hierarchy may change between processor generation.

    It uses memory controller ID details and populates nodes like:


    Also this patch adds few properties under dimm node. Finally make sure xscom nodes created before calling memory_parse().

Fast Reboot and Quiesce

We have a preliminary fast reboot implementation for POWER9 systems, which we look to enabling by default in the next release.

The OPAL Quiesce calls are designed to improve reliability and debuggability around reboot and error conditions. See the full API documentation for details: OPAL_QUIESCE.

  • fast-reboot: bare bones fast reboot implementation for POWER9

    This is an initial fast reboot implementation for p9 which has only been tested on the Witherspoon platform, and without the use of NPUs, NX/VAS, etc.

    This has worked reasonably well so far, with no failures in about 100 reboots. It is hidden behind the traditional fast-reboot experimental nvram option, until more platforms and configurations are tested.

  • fast-reboot: move boot CPU clean-up logically together with secondaries

    Move the boot CPU clean-up and state transition to active, logically together with secondaries. Don’t release secondaries from fast reboot hold until everyone has cleaned up and transitioned to active.

    This is cosmetic, but it is helpful to run the fast reboot state machine the same way on all CPUs.

  • fast-reboot: improve failure error messages

    Change existing failure error messages to PR_NOTICE so they get printed to the console, and add some new ones. It’s not a more severe class because it falls back to IPL on failure.

  • fast-reboot: quiesce opal before initiating a fast reboot

    Switch fast reboot to use quiescing rather than “wait for a while”.

    If firmware can not be quiesced, then fast reboot is skipped. This significantly improves the robustness of fast reboot in the face of bugs or unexpected latencies.

    Complexity of synchronization in fast-reboot is reduced, because we are guaranteed to be single-threaded when quiesce succeeds, so locks can be removed.

    In the case that firmware can be quiesced, then it will generally reduce fast reboot times by nearly 200ms, because quiescing usually takes very little time.

  • core: Add support for quiescing OPAL

    Quiescing is ensuring all host controlled CPUs (except the current one) are out of OPAL and prevented from entering. This can be use in debug and shutdown paths, particularly with system reset sequences.

    This patch adds per-CPU entry and exit tracking for OPAL calls, and adds logic to “hold” or “reject” at entry time, if OPAL is quiesced.

    An OPAL call is added, to expose the functionality to Linux, where it can be used for shutdown, kexec, and before generating sreset IPIs for debugging (so the debug code does not recurse into OPAL).

  • dctl: p9 increase thread quiesce timeout

    We require all instructions to be completed before a thread is considered stopped, by the dctl interface. Long running instructions like cache misses and CI loads may take a significant amount of time to complete, and timeouts have been observed in stress testing.

    Increase the timeout significantly, to cover this. The workbook just says to poll, but we like to have timeouts to avoid getting stuck in firmware.

POWER9 power saving

There is much improved support for deeper sleep/idle (stop) states on POWER9.

  • OCC: Increase max pstate check on P9 to 255

    This has changed from P8, we can now have > 127 pstates.

    This was observed on Boston during WoF bring up.

  • SLW: Add idle state stop5 for DD2.0 and above

    Adding stop5 idle state with rough residency and latency numbers.

  • SLW: Add p9_stop_api calls for IMC

    Add p9_stop_api for EVENT_MASK and PDBAR scoms. These scoms are lost on wakeup from stop11.

  • SCOM restore for DARN and XIVE

    While waking up from stop11, we want NCU_DARN_BAR to have enable bit set. Without this stop_api call, the value restored is without enable bit set. We loose NCU_SPEC_BAR when the quad goes into stop11, stop_api will restore while waking up from stop11.

  • SLW: Call p9_stop_api only if deep_states are enabled

    All init time p9_stop_api calls have been isolated to slw_late_init. If p9_stop_api fails, then the deep states can be excluded from device tree.

    For p9_stop_api called after device-tree for cpuidle is created , has_deep_states will be used to check if this call is even required.

  • Better handle errors in setting up sleep states (p9_stop_api)

    We won’t put affected stop states in the device tree if the wakeup engine is not present or has failed.

  • SCOM Restore: Increased the EQ SCOM restore limit.

    Commit increases the SCOM restore limit from 16 to 31.

  • hw/dts: retry special wakeup operation if core still gated

    It has been observed that in some cases the special wakeup operation can “succeed” but the core is still in a gated/offline state.

    Check for this state after attempting to wakeup a core and retry the wakeup if necessary.

  • core/direct-controls: add function to read core gated state

  • core/direct-controls: wait for core special wkup bit cleared

    When clearing special wakeup bit on a core, wait until the bit is actually cleared by the hardware in the status register until returning success.

    This may help avoid issues with back-to-back reads where the special wakeup request is cleared but the firmware is still processing the request and the next attempt to set the bit reads an immediate success from the previous operation.

  • p9_stop_api: PM: Added support for version control in SCOM restore entries.

    • adds version info in SCOM restore entry header
    • adds version specific details in SCOM restore entry header
    • retains old behaviour of SGPE Hcode’s base version
  • p9_stop_api: EQ SCOM Restore: Introduced version control in SCOM restore entry.

    • introduces version control in header of SCOM restore entry
    • ensures backward compatibility
    • introduces flexibility to handle any number of SCOM restore entry.

Secure and Trusted Boot for POWER9

We introduce support for Secure and Trusted Boot for POWER9 systems, with equal functionality that we have on POWER8 systems, that is, we have the mechanisms in place to boot to petitboot (i.e. to BOOTKERNEL).

See the Secure and Trusted Boot Library (LibSTB) Documentation for full documentation of OPAL secure and trusted boot.

Since skiboot-5.10-rc2:

  • stb: Put correct label (for skiboot) into container

    Hostboot will expect the label field of the stb header to contain “PAYLOAD” for skiboot or it will fail to load and run skiboot.

    The failure looks something like this:

    53.40896|ISTEP 20. 1 - host_load_payload
    53.65840|secure|Secureboot Failure plid = 0x90000755, rc = 0x1E07
    53.65881|System shutting down with error status 0x1E07
    53.67954|Error reported by secure (0x1E00) PLID 0x90000755
    53.67560|  Container's component ID does not match expected component ID
    53.67845|  ReasonCode 0x1e07 SECUREBOOT::RC_ROM_VERIFY
    53.67998|  UserData1   : 0x0000000000000000
    53.67999|  UserData2   : 0x0000000000000000
    53.68000|  Callout type             : Procedure Callout
    53.68000|  Procedure                : EPUB_PRC_HB_CODE
    53.68001|  Priority                 : SRCI_PRIORITY_HIGH
    53.68002|  Callout type             : Procedure Callout
    53.68003|  Procedure                : EPUB_PRC_FW_VERIFICATION_ERR
    53.68003|  Priority                 : SRCI_PRIORITY_HIGH

Since skiboot-5.10-rc1:

  • stb: Enforce secure boot if called before libstb initialized

  • stb: Correctly error out when no PCR for resource

  • core/init: move imc catalog preload init after the STB init.

    As a safer side move the imc catalog preload after the STB init to make sure the imc catalog resource get’s verified and measured properly during loading when both secure and trusted boot modes are on.

  • libstb: fix failure of calling trusted measure without STB initialization.

    When we load a flash resource during OPAL init, STB calls trusted measure to measure the given resource. There is a situation when a flash gets loaded before STB initialization then trusted measure cannot measure properly.

    So this patch fixes this issue by calling trusted measure only if the corresponding trusted init was done.

    The ideal fix is to make sure STB init done at the first place during init and then do the loading of flash resources, by that way STB can properly verify and measure the all resources.

  • libstb: fix failure of calling cvc verify without STB initialization.

    Currently in OPAL init time at various stages we are loading various PNOR partition containers from the flash device. When we load a flash resource STB calls the CVC verify and trusted measure(sha512) functions. So when we have a flash resource gets loaded before STB initialization, then cvc verify function fails to start the verify and enforce the boot.

    Below is one of the example failure where our VERSION partition gets loading early in the boot stage without STB initialization done.

    This is with secure mode off. STB: VERSION NOT VERIFIED, invalid param. buf=0x305ed930, len=4096 key-hash=0x0 hash-size=0

    In the same code path when secure mode is on, the boot process will abort.

    So this patch fixes this issue by calling cvc verify only if we have STB init was done.

    And also we need a permanent fix in init path to ensure STB init gets done at first place and then start loading all other flash resources.

  • libstb/tpm_chip: Add missing new line to print messages.

  • libstb: increase the log level of verify/measure messages to PR_NOTICE.

    Currently libstb logs the verify and hash caluculation messages in PR_INFO level. So when there is a secure boot enforcement happens in loading last flash resource(Ex: BOOTKERNEL), the previous verify and measure messages are not logged to console, which is not clear to the end user which resource is verified and measured. So this patch fixes this by increasing the log level to PR_NOTICE.

Since skiboot-5.9:

  • allow secure boot if not enforcing it

    We check the secure boot containers no matter what, only enforcing secure boot if we’re booting in secure mode. This gives us an extra layer of checking firmware is legit even when secure mode isn’t enabled, as well as being really useful for testing.

  • libstb/(create|print)-container: Sync with sb-signing-utils

    The sb-signing-utils project has improved upon the skeleton create-container tool that existed in skiboot, including being able to (quite easily) create signed images.

    This commit brings in that code (and makes it build in the skiboot build environment) and updates our skiboot.*.stb generating code to use the development keys. This means that by default, skiboot build process will let you build firmware that can do a secure boot with development keys.

    See Signing Firmware Code for details on firmware signing.

    We also update print-container as well, syncing it with the upstream project.

    Derived from at v0.3-5-gcb111c03ad7f (Some discussion ongoing on the changes, another sync will come shortly)

  • doc: update libstb documentation with POWER9 changes. See: Secure and Trusted Boot Library (LibSTB) Documentation.

    POWER9 changes reflected in the libstb:

    • bumped ibm,secureboot node to v2
    • added ibm,cvc node
    • hash-algo superseded by hw-key-hash-size
  • libstb/cvc: update memory-region to point to /reserved-memory

    The linux documentation, reserved-memory.txt, says that memory-region is a phandle that pairs to a children of /reserved-memory.

    This updates /ibm,secureboot/ibm,cvc/memory-region to point to

    /reserved-memory/secure-crypt-algo-code instead of /ibm,hostboot/reserved-memory/secure-crypt-algo-code.

  • libstb: add support for ibm,secureboot-v2

    ibm,secureboot-v2 changes:

    • The Container Verification Code is represented by the ibm,cvc node.
    • Each ibm,cvc child describes a CVC service.
    • hash-algo is superseded by hw-key-hash-size.
  • hdata/tpmrel.c: add ibm, cvc device tree node

    In P9, the Container Verification Code is stored in a hostboot reserved memory and the list of provided CVC services is stored in the TPMREL_IDATA_HASH_VERIF_OFFSETS idata array. Each CVC service has an offset and version.

    This adds the ibm,cvc device tree node and its documentation.

  • hdata/tpmrel.c: add firmware event log info to the tpm node

    This parses the firmware event log information from the secureboot_tpm_info HDAT structure and add it to the tpm device tree node.

    There can be multiple secureboot_tpm_info entries with each entry corresponding to a master processor that has a tpm device, however, multiple tpm is not supported.

  • hdata/spira: add ibm,secureboot node in P9

    In P9, skiboot builds the device tree from the HDAT. These are the “ibm,secureboot” node changes compared to P8:

    • The Container-Verification-Code (CVC), a.k.a. ROM code, is no longer stored in a secure ROM with static address. In P9, it is stored in a hostboot reserved memory and each service provided also has a version, not only an offset.
    • The hash-algo property is not provided via HDAT, instead it provides the hw-key-hash-size, which is indeed the information required by the CVC to verify containers.

    This parses the iplparams_sysparams HDAT structure and creates the “ibm,secureboot”, which is bumped to “ibm,secureboot-v2”.

    In “ibm,secureboot-v2”:

    • hash-algo property is superseded by hw-key-hash-size.
    • container verification code is explicitly described by a child node. Added in a subsequent patch.

    See ibm,secureboot for documentation.

  • libstb/tpm_chip.c: define pr_fmt and fix messages logged

    This defines pr_fmt and also fix messages logged:

    • EV_SEPARATOR instead of 0xFFFFFFFF
    • when an event is measured it also prints the tpm id, event type and event log length

    Now we can filter the messages logged by libstb and its sub-modules by running:

    grep STB /sys/firmware/opal/msglog
  • libstb/tss: update the list of event types supported

    Skiboot, precisely the tpmLogMgr, initializes the firmware event log by calculating its length so that a new event can be recorded without exceeding the log size. In order to calculate the size, it walks through the log until it finds a specific event type. However, if the log has an unknown event type, the tpmLogMgr will not be able to reach the end of the log.

    This updates the list of event types with all of those supported by hostboot. Thus, skiboot can properly calculate the event log length.

  • tpm_i2c_nuvoton: add nuvoton, npct601 to the compatible property

    The linux kernel doesn’t have a driver compatible with “nuvoton,npct650”, but it does have for “nuvoton,npct601”, which should also be compatible with npct650.

    This adds “nuvoton,npct601” to the compatible devtree property.

  • libstb/trustedboot.c: import stb_final() from stb.c

    The stb_final() primary goal is to measure the event EV_SEPARATOR into PCR[0-7] when trusted boot is about to exit the boot services.

    This imports the stb_final() from stb.c into trustedboot.c, but making the following changes:

    • Rename it to trustedboot_exit_boot_services().
    • As specified in the TCG PC Client specification, EV_SEPARATOR events must be logged with the name 0xFFFFFF.
    • Remove the ROM driver clean-up call.
    • Don’t allow code to be measured in skiboot after trustedboot_exit_boot_services() is called.
  • libstb/cvc.c: import softrom behaviour from drivers/sw_driver.c

    Softrom is used only for testing with mambo. By setting compatible=”ibm,secureboot-v1-softrom” in the “ibm,secureboot” node, firmware images can be properly measured even if the Container-Verification-Code (CVC) is not available. In this case, the mbedtls_sha512() function is used to calculate the sha512 hash of the firmware images.

    This imports the softrom behaviour from libstb/drivers/sw_driver.c code into cvc.c, but now softrom is implemented as a flag. When the flag is set, the wrappers for the CVC services work the same way as in sw_driver.c.

  • libstb/trustedboot.c: import tb_measure() from stb.c

    This imports tb_measure() from stb.c, but now it calls the CVC sha512 wrapper to calculate the sha512 hash of the firmware image provided.

    In trustedboot.c, the tb_measure() is renamed to trustedboot_measure().

    The new function, trustedboot_measure(), no longer checks if the container payload hash calculated at boot time matches with the hash found in the container header. A few reasons:

    • If the system admin wants the container header to be checked/validated, the secure boot jumper must be set. Otherwise, the container header information may not be reliable.

    • The container layout is expected to change over time. Skiboot would need to maintain a parser for each container layout change.

    • Skiboot could be checking the hash against a container version that is not supported by the Container-Verification-Code (CVC).

      The tb_measure() calls are updated to trustedboot_measure() in a subsequent patch.

  • libstb/secureboot.c: import sb_verify() from stb.c

    This imports the sb_verify() function from stb.c, but now it calls the CVC verify wrapper in order to verify signed firmware images. The hw-key-hash and hw-key-hash-size initialized in secureboot.c are passed to the CVC verify function wrapper.

    In secureboot.c, the sb_verify() is renamed to secureboot_verify(). The sb_verify() calls are updated in a subsequent patch.


  • xive: Don’t bother cleaning up disabled EQs in reset

    Additionally, warn if we find an enabled one that isn’t one of the firmware built-in queues.

  • xive: Warn on valid VPs found in abnormal cases

    If an allocated VP is left valid at xive_reset() or Linux tries to free a valid (enabled) VP block, print errors. The former happens occasionally if kdump’ing while KVM is running so keep it as a debug message. The latter is a programming error in Linux so use a an error log level.

  • xive: Properly reserve built-in VPs in non-group mode

    This is not normally used but if the #define is changed to disable block group mode we would incorrectly clear the buddy completely without marking the built-in VPs reserved.

  • xive: Quieten debug messages in standard builds

    This makes a bunch of messages, especially the per-CPU ones, only enabled in debug builds. This avoids clogging up the OPAL logs with XIVE related messages that have proven not being particularly useful for field defects.

  • xive: Implement “single escalation” feature

    This adds a new VP flag to control the new DD2.0 “single escalation” feature.

    This feature allows us to have a single escalation interrupt per VP instead of one per queue.

    It works by hijacking queue 7 (which is this no longer usable when that is enabled) and exploiting two new hardware bits that will:

    • Make the normal queues (0..6) escalate unconditionally thus ignoring the ESe bits.
    • Route the above escalations to queue 7
    • Have queue 7 silently escalate without notification

    Thus the escalation of queue 7 becomes the one escalation interrupt for all the other queues.

  • xive: When disabling a VP, wipe all of its settings

  • xive: Improve cleaning up of EQs

    Factors out the function that sets an EQ back to a clean state and add a cleaning pass for queue left enabled when freeing a block of VPs.

  • xive: When disabling an EQ, wipe all of its settings

    This avoids having configuration bits left over

  • xive: Define API for single-escalation VP mode

    This mode allows all queues of a VP to use the same escalation interrupt, at the cost of losing priority 7.

    This adds the definition and documentation of the API, the implementation will come next.

  • xive: Fix ability to clear some EQ flags

    We could never clear “unconditional notify” and “escalate”

  • xive: Update inits for DD2.0

    This updates some inits based on information from the HW designers. This includes enabling some new DD2.0 features that we don’t yet exploit.

  • xive: Ensure VC informational FIRs are masked

    Some HostBoot versions leave those as checkstop, they are harmless and can sometimes occur during normal operations.

  • xive: Fix occasional VC checkstops in xive_reset

    The current workaround for the scrub bug described in __xive_cache_scrub() has an issue in that it can leave dirty invalid entries in the cache.

    When cleaning up EQs or VPs during reset, if we then remove the underlying indirect page for these entries, the XIVE will checkstop when trying to flush them out of the cache.

    This replaces the existing workaround with a new pair of workarounds for VPs and EQs:

    • The VP one does the dummy watch on another entry than the one we scrubbed (which does the job of pushing old stores out) using an entry that is known to be backed by a permanent indirect page.
    • The EQ one switches to a more efficient workaround which consists of doing a non-side-effect ESB load from the EQ’s ESe control bits.
  • xive: Do not return a trigger page for an escalation interrupt

    This is bogus, we don’t support them. (Thankfully the callers didn’t actually try to use this on escalation interrupts).

  • xive: Mark a freed IRQs IVE as valid and masked

    Removing the valid bit means a FIR will trip if it’s accessed inadvertently. Under some circumstances, the XIVE will speculatively access an IVE for a masked interrupt and trip it. So make sure that freed entries are still marked valid (but masked).


Since skiboot-5.10-rc3:

  • phb3/phb4/p7ioc: Document supported TCE sizes in DT

    Add a new property, “ibm,supported-tce-sizes”, to advertise to Linux how big the available TCE sizes are. Each value is a bit shift, from smallest to largest.

  • phb4: Fix TCE page size

    The page sizes for TCEs on P9 were inaccurate and just copied from PHB3, so correct them.

  • Revert “pci: Shared slot state synchronisation for hot reset”

    An issue was found in shared slot reset where the system can be stuck in an infinite loop, pull the code out until there’s a proper fix.

    This reverts commit 1172a6c57ff3c66f6361e572a1790cbcc0e5ff37.

  • hdata/iohub: Use only wildcard slots for pluggables

    We don’t want to cause a VID:DID check against pluggable devices, as they may use multiple devids.

    Narrow the condition under which VID:DID is listed in the dt, so that we’ll end up creating a wildcard slot for these instead.

Since skiboot-5.9:

  • pci: Shared slot state synchronisation for hot reset

    When a device is shared between two PHBs, it doesn’t get reset properly unless both PHBs issue a hot reset at “the same time”. Practically this means a hot reset needs to be issued on both sides, and neither should bring the link up until the reset on both has completed.

  • pci: Track peers of slots

    Witherspoon introduced a new concept where one physical slot is shared between two PHBs. Making a slot aware of its peer enables syncing between them where necessary.


Since skiboot-5.10-rc4:

  • phb4: Disable lane eq when retrying some nvidia GEN3 devices

    This fixes these nvidia cards training at only GEN2 spends rather than GEN3 by disabling PCIe lane equalisation.

    Firstly we check if the card is in a whitelist. If it is and the link has not trained optimally, retry with lane equalisation off. We do this on all POWER9 chip revisions since this is a device issue, not a POWER9 chip issue.

Since skiboot-5.10-rc2:

  • phb4: Only escalate freezes on MMIO load where necessary

    In order to work around a hardware issue, MMIO load freezes were escalated to fences on every chip. Now that hardware no longer requires this, restrict escalation to the chips that actually need it.

Since skiboot-5.9:

  • phb4: Change PCI MMIO timers

    Currently we have a mismatch between the NCU and PCI timers for MMIO accesses. The PCI timers must be lower than the NCU timers otherwise it may cause checkstops.

    This changes PCI timeouts controlled by skiboot to 33-50ms. It should be forwards and backwards compatible with expected hostboot changes to the NCU timer.

  • phb4: Change default GEN3 lane equalisation setting to 0x54

    Currently our GEN3 lane equalisation settings are set to 0x77. Change this to 0x54. This change will allow us to train at GEN3 in a shorter time and more consistently.

    This setting gives us a TX preset 0x4 and RX hint 0x5. This gives a boost in gain for high frequency signalling. It allows the most optimal continuous time linear equalizers (CTLE) for the remote receiver port and de-emphasis and pre-shoot for the remote transmitter port.

    Machine Readable Workbooks (MRW) are moving to this new value also.

  • phb4: Init changes

    These init changes for phb4 from the HW team.

    Link down are now endpoint recoverable (ERC) rather than PHB fatal errors.

    BLIF Completion Timeout Error now generate an interrupt rather than causing freeze events.

  • phb4: Fix lane equalisation setting

    Fix cut and paste from phb3. The sizes have changes now we have GEN4, so the check here needs to change also

    Without this we end up with the default settings (all ‘7’) rather than what’s in HDAT.

  • hdata: Fix copying GEN4 lane equalisation settings

    These aren’t copied currently but should be.

  • phb4: Fix PE mapping of M32 BAR

    The M32 BAR is the PHB4 region used to map all the non-prefetchable or 32-bit device BARs. It’s supposed to have its segments remapped via the MDT and Linux relies on that to assign them individual PE#.

    However, we weren’t configuring that properly and instead used the mode where PE# == segment#, thus causing EEH to freeze the wrong device or PE#.

  • phb4: Fix lost bit in PE number on config accesses

    A PE number can be up to 9 bits, using a uint8_t won’t fly..

    That was causing error on config accesses to freeze the wrong PE.

  • phb4: Update inits

    New init value from HW folks for the fence enable register.

    This clears bit 17 (CFG Write Error CA or UR response) and bit 22 (MMIO Write DAT_ERR Indication) and sets bit 21 (MMIO CFG Pending Error)


Since skiboot-5.10-rc2:

  • capi: Enable channel tag streaming for PHB in CAPP mode

    We re-enable channel tag streaming for PHB in CAPP mode as without it PEC was waiting for cresp for each DMA write command before sending a new DMA write command on the Powerbus. This resulted in much lower DMA write performance than expected.

    The patch updates enable_capi_mode() to remove the masking of channel_streaming_en bit in PBCQ Hardware Configuration Register. Also does some re-factoring of the code that updates this register to use xscom_write_mask instead of xscom_read followed by a xscom_write.

Since skiboot-5.10-rc1:

  • capi: Fix the max tlbi divider and the directory size.

    Switch to 512KB mode (directory size) as we don’t use bit 48 of the tag in addressing the array. This mode is controlled by the Snoop CAPI Configuration Register. Set the maximum of the number of data polls received before signaling TLBI hang detect timer expired. The value of ‘0000’ is equal to 16.

Since skiboot-5.9:

  • capi: Disable CAPP virtual machines

    When exercising more than one CAPI accelerators simultaneously in cache coherency mode, the verification team is seeing a deadlock. To fix this a workaround of disabling CAPP virtual machines is suggested. These ‘virtual machines’ let PSL queue multiple CAPP commands for servicing by CAPP there by increasing throughput. Below is the error scenario described by the h/w team:

    ” With virtual machines enabled we had a deadlock scenario where with 2 or more CAPI’s in a system you could get in a deadlock scenario due to cast-outs that are required break the deadlock (evict lines that another CAPI is requesting) get stuck in the virtual machine queue by a command ahead of it that is being retried by the same scenario in the other CAPI. “

  • capi: Perform capp recovery sequence only when PBCQ is idle

    Presently during a CRESET the CAPP recovery sequence can be executed multiple times in case PBCQ on the PEC is still busy processing in/out bound in-flight transactions.

  • xive: Mask MMIO load/store to bad location FIR

    For opencapi, the trigger page of an interrupt is mapped to user space. The intent is to write the page to raise an interrupt but there’s nothing to prevent a user process from reading it, which has the unfortunate consequence of checkstopping the system.

    Mask the FIR bit raised when an MMIO operation targets an invalid location. It’s the recommendation from recent documentation and hostboot is expected to mask it at some point. In the meantime, let’s play it safe.

  • phb4: Dump CAPP error registers when it asserts link down

    This patch introduces a new function phb4_dump_app_err_regs() that dumps CAPP error registers in case the PEC nestfir register indicates that the fence was due to a CAPP error (BIT-24).

    Contents of these registers are helpful in diagnosing CAPP issues. Registers that are dumped in phb4_dump_app_err_regs() are:

    • CAPP FIR Register
    • CAPP APC Master Error Report Register
    • CAPP Snoop Error Report Register
    • CAPP Transport Error Report Register
    • CAPP TLBI Error Report Register
    • CAPP Error Status and Control Register
  • capi: move the acknowledge of the HMI interrupt

    We need to acknowledge an eventual HMI initiated by the previous forced fence on the PHB to work around a non-existent PE in the phb4_creset() function. For this reason do_capp_recovery_scoms() is called now at the beginning of the step: PHB4_SLOT_CRESET_WAIT_CQ

  • capi: update ci store buffers and dma engines

    The number of read (APC type traffic) and mmio store (MSG type traffic) resources assigned to the CAPP is controlled by the CAPP control register.

    According to the type of CAPI cards present on the server, we have to configure differently the CAPP messages and the DMA read engines given to the CAPP for use.


  • core/hmi: Display chip location code while displaying core FIR.

  • core/hmi: Do not display FIR details if none of the bits are set.

    So that we don’t flood OPAL console logs with information that is not useful.

  • opal/hmi: HMI logging with location code info.

    Add few HMI debug prints with location code info few additional info.

    No functionality change.

    With this patch the log messages will look like:

    [210612.175196744,7] HMI: Received HMI interrupt: HMER = 0x0840000000000000
    [210612.175200449,7] HMI: [Loc: UOPWR.1302LFA-Node0-Proc1]: P:8 C:16 T:1: TFMR(2d12000870e04020) Timer Facility Error
    [210660.259689526,7] HMI: Received HMI interrupt: HMER = 0x2040000000000000
    [210660.259695649,7] HMI: [Loc: UOPWR.1302LFA-Node0-Proc0]: P:0 C:16 T:1: Processor recovery Done.
  • core/hmi: Use pr_fmt macro for tagging log messages

    No functionality changes.

  • opal: Get chip location code

    and store it under proc_chip for quick reference during HMI handling code.


  • occ-sensors: Fix up quad/gpu location mix-up

    The GPU and QUAD sensor location types are swapped compared to what exists in the OCC code base which is authoritative. Fix them up.

  • sensors: occ: Skip counter type of sensors

    Don’t add counter type of sensors to device-tree as they don’t fit into hwmon sensor interface.

  • sensors: dts: Assert special wakeup on idle cores while reading temperature

    In P9, when a core enters a stop state, its clocks will be stopped to save power and hence we will not be able to perform a SCOM operation to read the DTS temperature sensor. Hence, assert a special wakeup on cores that have entered a stop state in order to successfully complete the SCOM operation.

  • sensors: occ: Skip power sensors with zero sample value

    APSS is not available on platforms like Zaius, Romulus where OCC can only measure Vdd (core) and Vdn (nest) power from the AVSbus reading. So all the sensors for APSS channels will be populated with 0. Different component power sensors like system, memory which point to the APSS channels will also be 0.

    As per OCC team (Martha Broyles) zeroed power sensor means that the system doesn’t have it. So this patch filters out these sensors.

  • sensors: occ: Skip GPU sensors for non-gpu systems

  • sensors: Fix dtc warning for new occ in-band sensors.

    dtc complains about missing reg property when a DT node is having a unit name or address but no reg property.

    /ibm,opal/sensors/vrm-in@c00004 has a unit name, but no reg property
    /ibm,opal/sensors/gpu-in@c0001f has a unit name, but no reg property
    /ibm,opal/sensor-groups/occ-js@1c00040 has a unit name, but no reg property

    This patch fixes these warnings for new occ in-band sensors and also for sensor-groups by adding necessary properties.

  • sensors: Fix dtc warning for dts sensors.

    dtc complains about missing reg property when a DT node is having a unit name or address but no reg property.

    Example warning for core dts sensor:

    /ibm,opal/sensors/core-temp@5c has a unit name, but no reg property
    /ibm,opal/sensors/core-temp@804 has a unit name, but no reg property

    This patch fixes this by adding necessary properties.

  • hw/occ: Fix psr cpu-to-gpu sensors node dtc warning.

    dtc complains about missing reg property when a DT node is having a unit name or address but no reg property.

    /ibm,opal/power-mgt/psr/cpu-to-gpu@0 has a unit name, but no reg property
    /ibm,opal/power-mgt/psr/cpu-to-gpu@100 has a unit name, but no reg property

    This patch fixes this by adding necessary properties.

General fixes

Since skiboot-5.10-rc3:

  • core: Fix mismatched names between reserved memory nodes & properties

    OPAL exposes reserved memory regions through the device tree in both new (nodes) and old (properties) formats.

    However, the names used for these don’t match - we use a generated cell address for the nodes, but the plain region name for the properties.

    This fixes a warning from FWTS

Since skiboot-5.10-rc2:

  • vas: Disable VAS/NX-842 on some P9 revisions

    VAS/NX-842 are not functional on some P9 revisions, so disable them in hardware and skip creating their device tree nodes.

    Since the intent is to prevent OS from configuring VAS/NX, we remove only the platform device nodes but leave the VAS/NX DT nodes under xscom (i.e we don’t skip add_vas_node() in hdata/spira.c)

  • core/device.c: Fix dt_find_compatible_node

    dt_find_compatible_node() and dt_find_compatible_node_on_chip() are used to find device nodes under a parent/root node with a given compatible property.

    dt_next(root, prev) is used to walk the child nodes of the given parent and takes two arguments - root contains the parent node to walk whilst prev contains the previous child to search from so that it can be used as an iterator over all children nodes.

    The first iteration of dt_find_compatible_node(root, prev) calls dt_next(root, root) which is not a well defined operation as prev is assumed to be child of the root node. The result is that when a node contains no children it will start returning the parent nodes siblings until it hits the top of the tree at which point a NULL derefence is attempted when looking for the root nodes parent.

    Dereferencing NULL can result in undesirable data exceptions during system boot and untimely non-hilarious system crashes. dt_next() should not be called with prev == root. Instead we add a check to dt_next() such that passing prev = NULL will cause it to start iterating from the first child node (if any).

    This manifested itself in a crash on boot on ZZ systems.

  • hw/occ: Fix fast-reboot crash in P8 platforms.

    commit 85a1de35cbe4 (“fast-boot: occ: Re-parse the pstate table during fast-boot” ) breaks the fast-reboot on P8 platforms while reiniting the OCC pstates. On P8 platforms OPAL adds additional two properties #address-cells and #size-cells under ibm,opal/power-mgmt/ DT node. While in fast-reboot same properties adding back to the same node results in Duplicate properties and hence fast-reboot fails with below traces.

    [  541.410373292,5] OCC: All Chip Rdy after 0 ms
    [  541.410488745,3] Duplicate property "#address-cells" in node /ibm,opal/power-mgt
    [  541.410694290,0] Aborting!
    CPU 0058 Backtrace:
     S: 0000000031d639d0 R: 000000003001367c   .backtrace+0x48
     S: 0000000031d63a60 R: 000000003001a03c   ._abort+0x4c
     S: 0000000031d63ae0 R: 00000000300267d8   .new_property+0xd8
     S: 0000000031d63b70 R: 0000000030026a28   .__dt_add_property_cells+0x30
     S: 0000000031d63c10 R: 000000003003ea3c   .occ_pstates_init+0x984
     S: 0000000031d63d90 R: 00000000300142d8   .load_and_boot_kernel+0x86c
     S: 0000000031d63e70 R: 000000003002586c   .fast_reboot_entry+0x358
     S: 0000000031d63f00 R: 00000000300029f4   fast_reset_entry+0x2c

    This patch fixes this issue by removing these two properties on P8 while doing OCC pstates re-init in fast-reboot code path.

Since skiboot-5.10-rc1:

  • fast-reboot: occ: Re-parse the pstate table during fast-reboot

    OCC shares the frequency list to host by copying the pstate table to main memory in HOMER. This table is parsed during boot to create device-tree properties for frequency and pstate IDs. OCC can update the pstate table to present a new set of frequencies to the host. But host will remain oblivious to these changes unless it is re-inited with the updated device-tree CPU frequency properties. So this patch allows to re-parse the pstate table and update the device-tree properties during fast-reboot.

    OCC updates the pstate table when asked to do so using pstate-table bias command. And this is mainly used by WOF team for characterization purposes.

  • fast-reboot: move pci_reset error handling into fast-reboot code

    pci_reset() currently does a platform reboot if it fails. It should not know about fast-reboot at this level, so instead have it return an error, and the fast reboot caller will do the platform reboot.

    The code essentially does the same thing, but flexibility is improved. Ideally the fast reboot code should perform pci_reset and all such fail-able operations before the CPU resets itself and destroys its own stack. That’s not the case now, but that should be the goal.

Since skiboot-5.9:

  • lpc: Clear pending IRQs at boot

    When we come in from hostboot the LPC master has the bus reset indicator set. This error isn’t handled until the host kernel unmasks interrupts, at which point we get the following spurious error:

    [   20.053560375,3] LPC: Got LPC reset on chip 0x0 !
    [   20.053564560,3] LPC[000]: Unknown LPC error Error address reg: 0x00000000

    Fix this by clearing the various error bits in the LPC status register before we initialise the skiboot LPC bus driver.

  • hw/imc: Check ucode state before exposing units to Linux

    disable_unavailable_units() checks whether the ucode is in the running state before enabling the nest units in the device tree. From a recent debug, it is found that on some system boot, ucode is not loaded and running in all the chips in the system. And this caused a fail in OPAL_IMC_COUNTERS_STOP call where we check for ucode state on each chip. Bug here is that disable_unavailable_units() checks the state of the ucode only in boot cpu chip. Patch adds a condition in disable_unavailable_units() to check for the ucode state in all the chip before enabling the nest units in the device tree node.

  • hdata/vpd: Add vendor property

    ibm,vpd blob contains VN field. Use that to populate vendor property for various FRU’s.

  • hdata/vpd: Fix DTC warnings

    All the nodes under the vpd hierarchy have a unit address (their SLCA index) but no reg properties. Add them and their size/address cells to squash the warnings.

  • HDAT/i2c: Fix SPD EEPROM compatible string

    Hostboot doesn’t give us accurate information about the DIMM SPD devices. Hack around by assuming any EEPROM we find on the SPD I2C master is an SPD EEPROM.

  • hdata/i2c: Fix 512Kb EEPROM size

    There’s no such thing as a 412Kb EEPROM.

  • libflash/mbox-flash: fall back to requesting lower MBOX versions from BMC

    Some BMC mbox implementations seem to sometimes mysteriously fail when trying to negotiate v3 when they only support v2. To work around this, we can fall back to requesting lower mbox protocol versions until we find one that works.

    In theory, this should already “just work”, but we have a counter example, which this patch fixes.

  • IPMI: Fix platform.cec_reboot() null ptr checks

    Kudos to Hugo Landau who reported this in:

  • hdata: Add location code property to xscom node

    This patch adds chip location code property to xscom node.

  • p8-i2c: Limit number of retry attempts

    Current we will attempt to start an I2C transaction until it succeeds. In the event that the OCC does not release the lock on an I2C bus this results in an async token being held forever and the kernel thread that started the transaction will block forever while waiting for an async completion message. Fix this by limiting the number of attempts to start the transaction.

  • p8-i2c: Don’t write the watermark register at init

    On P9 the I2C master is shared with the OCC. Currently the watermark values are set once at init time which is bad for two reasons:

    1. We don’t take the OCC master lock before setting it. Which may cause issues if the OCC is currently using the master.
    2. The OCC might change the watermark levels and we need to reset them.

    Change this so that we set the watermark value when a new transaction is started rather than at init time.

  • hdata: Rename ‘fsp-ipl-side’ as ‘sp-ipl-side’

    as OPAL is building device tree for both FSP and BMC system. Also I don’t see anyone using this property today. Hence renaming should be fine.

  • hdata/vpd: add support for parsing CPU VRML records

    Allows skiboot to parse out the processor part/serial numbers on OpenPOWER P9 machines.

  • core/lock: Introduce atomic cmpxchg and implement try_lock with it

    cmpxchg will be used in a subsequent change, and this reduces the amount of asm code.

  • direct-controls: add xscom error handling for p8

    Add xscom checks which will print something useful and return error back to callers (which already have error handling plumbed in).

  • direct-controls: p8 implementation of generic direct controls

    This reworks the sreset functionality that was brought over from fast-reboot, and fits it under the generic direct controls APIs.

    The fast reboot APIs are implemented using generic direct controls, which also makes them available on p9.

  • fast-reboot: allow mambo fast reboot independent of CPU type

    Don’t tie mambo fast reboot to POWER8 CPU type.

  • fast-reboot: remove delay after sreset

    There is a 100ms delay when targets reach sreset which does not appear to have a good purpose. Remove it and therefore reduce the sreset timeout by the same amount.

  • fast-reboot: add more barriers around cpu state changes

    This is a bit of paranoia, but when a CPU changes state to signal it has reached a particular point, all previous stores should be visible.

  • fast-reboot: add sreset timeout detection and handling

    Have the initiator wait for all its sreset targets to call in, and time out after 200ms if they did not. Fail and revert to IPL reboot.

    Testing indicates that after successful sreset_all_others(), it takes less than 102ms (in hundreds of fast reboots) for secondaries to call in. 100 of that is due to an initial delay, but core un-splitting was not measured.

  • fast-reboot: make spin loops consistent and SMT friendly

  • fast-reboot: add sreset_all_others error handling

    Pass back failures from sreset_all_others, also change return codes to OPAL form in sreset_all_prepare to match.

    Errors will revert to the IPL path, so it’s not critical to completely clean up everything if that would complicate things. Detecting the error and failing is the important thing.

  • fast-reboot: restore SMT priority on spin loop exit

  • Add documentation for ibm, firmware-versions device tree node

  • NX: Print read xscom config failures.

    Currently in NX, only write xscom config failures are tracing. Add trace statements for read xscom config failures too. No functional changes.

  • hw/nx: Fix NX BAR assignments

    The NX rng BAR is used by each core to source random numbers for the DARN instruction. Currently we configure each core to use the NX rng of the chip that it exists on. Unfortunately, the NX can be de-configured by hostboot and in this case we need to use the NX of a different chip.

    This patch moves the BAR assignments for the NX into the normal nx-rng init path. This lets us check if the normal (chip local) NX is active when configuring which NX a core should use so that we can fall back gracefully.

  • FSP-elog: Reduce verbosity of elog messages

    These messages just fill up the opal console log with useless messages resulting in us losing useful information.

    They have been like this since the first commit in skiboot. Make them trace.

  • core/bitmap: fix bitmap iteration limit corruption

    The bitmap iterators did not reduce the number of bits to scan when searching for the next bit, which would result in them overrunning their bitmap.

    These are only used in one place, in xive reset, and the effect is that the xive reset code will keep zeroing memory until it reaches a block of memory of MAX_EQ_COUNT >> 3 bits in length, all zeroes.

  • hw/imc: always enable “imc_nest_chip” exports property

    imc_dt_update_nest_node() adds a “imc_nest_chip” property to the “exports” node (under opal_node) to view nest counter region. This comes handy when debugging ucode runtime errors (like counter data update or control block update so on…). And current code enables the property only if the microcode is in running state at system boot. To aid the debug of ucode not running/starting issues at boot, enable the addition of “imc_nest_chip” property always.


Since skiboot-5.10-rc2:

  • npu2: Disable TVT range check when in bypass mode

    On POWER9 the GPUs need to be able to access the MMIO memory space. Therefore the TVT range check needs to include the MMIO address space. As any possible range check would cover all of memory anyway this patch just disables the TVT range check all together when bypassing the TCE tables.

  • hw/npu2: support creset of npu2 devices

    creset calls in the hw procedure that resets the PHY, we don’t take them out of reset, just put them in reset.

    this fixes a kexec issue.

Since skiboot-5.10-rc1:

  • npu2/tce: Fix page size checking

    The page size is encoded in the TVT data [59:63] as @shift+11 but the tce_kill handler does not do the math right; this fixes it.

Since skiboot-5.9:

  • npu2-hw-procedures.c: Correct phy lane mapping

    Each NVLINK2 device is associated with a particular group of OBUS lanes via a lane mask which is read from HDAT via the device-tree. However Skiboot’s interpretation of lane mask was different to what is exported from the HDAT.

    Specifically the lane mask bits in the HDAT are encoded in IBM bit ordering for a 24-bit wide value. So for example in normal bit ordering lane-0 is represented by having lane-mask bit 23 set and lane-23 is represented by lane-mask bit 0. This patch alters the Skiboot interpretation to match what is passed from HDAT.

  • npu2-hw-procedures.c: Power up lanes during ntl reset

    Newer versions of Hostboot will not power up the NVLINK2 PHY lanes by default. The phy_reset procedure already powers up the lanes but they also need to be powered up in order to access the DL.

    The reset_ntl procedure is called by the device driver to bring the DL out of reset and get it into a working state. Therefore we also need to add lane and clock power up to the reset_ntl procedure.

  • npu2.c: Add PE error detection

    Invalid accesses from the GPU can cause a specific PE to be frozen by the NPU. Add an interrupt handler which reports the frozen PE to the operating system via as an EEH event.

  • npu2.c: Fix XIVE IRQ alignment

  • npu2: hw-procedures: Refactor reset_ntl procedure

    Change the implementation of reset_ntl to match the latest programming guide documentation.

  • npu2: hw-procedures: Add phy_rx_clock_sel()

    Change the RX clk mux control to be done by software instead of HW. This avoids glitches caused by changing the mux setting.

  • npu2: hw-procedures: Change phy_rx_clock_sel values

    The clock selection bits we set here are inputs to a state machine.

    DL clock select (bits 30-31)


    lane 0 clock


    lane 7 clock


    grid clock



    To recover from a potential glitch, we need to ensure that the value we set forces a state change. Our current sequence is to set 0x3 followed by 0x1. With the above now known, that is actually a no-op followed by selection of lane 7. Depending on lane reversal, that selection is not a state change for some bricks.

    The way to force a state change in all cases is to switch to the grid clock, and then back to a lane.

  • npu2: hw-procedures: Manipulate IOVALID during training

    Ensure that the IOVALID bit for this brick is raised at the start of link training, in the reset_ntl procedure.

    Then, to protect us from a glitch when the PHY clock turns off or gets chopped, lower IOVALID for the duration of the phy_reset and phy_rx_dccal procedures.

  • npu2: hw-procedures: Add check_credits procedure

    As an immediate mitigation for a current hardware glitch, add a procedure that can be used to validate NTL credit values. This will be called as a safeguard to check that link training succeeded.

    Assert that things are exactly as we expect, because if they aren’t, the system will experience a catastrophic failure shortly after the start of link traffic.

  • npu2: Print bdfn in NPU2DEV* logging macros

    Revise the NPU2DEV{DBG,INF,ERR} logging macros to include the device’s bdfn. It’s useful to know exactly which link we’re referring to.

    For instance, instead of

    [  234.044921238,6] NPU6: Starting procedure reset_ntl
    [  234.048578101,6] NPU6: Starting procedure reset_ntl
    [  234.051049676,6] NPU6: Starting procedure reset_ntl
    [  234.053503542,6] NPU6: Starting procedure reset_ntl
    [  234.057182864,6] NPU6: Starting procedure reset_ntl
    [  234.059666137,6] NPU6: Starting procedure reset_ntl

    we’ll get

    [  234.044921238,6] NPU6:0:0.0 Starting procedure reset_ntl
    [  234.048578101,6] NPU6:0:0.1 Starting procedure reset_ntl
    [  234.051049676,6] NPU6:0:0.2 Starting procedure reset_ntl
    [  234.053503542,6] NPU6:0:1.0 Starting procedure reset_ntl
    [  234.057182864,6] NPU6:0:1.1 Starting procedure reset_ntl
    [  234.059666137,6] NPU6:0:1.2 Starting procedure reset_ntl
  • npu2: Move to new GPU memory map

    There are three different ways we configure the MCD and memory map.

    1. Old way (current way)
      Skiboot configures the MCD and puts GPUs at 4TB and below
    2. New way with MCD
      Hostboot configures the MCD and skiboot puts GPU at 4TB and above
    3. New way without MCD
      No one configures the MCD and skiboot puts GPU at 4TB and below

    The patch keeps option 1 and adds options 2 and 3.

    The different configurations are detected using certain scoms (see patch).

    Option 1 will go away eventually as it’s a configuration that can cause xstops or data integrity problems. We are keeping it around to support existing hostboot.

    Option 2 supports only 4 GPUs and 512GB of memory per socket.

    Option 3 supports 6 GPUs and 4TB of memory but may have some performance impact.

  • phys-map: Rename GPU_MEM to GPU_MEM_4T_DOWN

    This map is soon to be replaced, but we are going to keep it around for a little while so that we support older hostboot firmware.

Platform Specific Fixes


  • Witherspoon: Remove old Witherspoon platform definition

    An old Witherspoon platform definition was added to aid the transition from versions of Hostboot which didn’t have the correct NVLINK2 HDAT information available and/or planar VPD. These system should now be updated so remove the possibly incorrect default assumption.

    This may disable NVLINK2 on old out-dated systems but it can easily be restored with the appropriate FW and/or VPD updates. In any case there is a a 50% chance the existing default behaviour was incorrect as it only supports 6 GPU systems. Using an incorrect platform definition leads to undefined behaviour which is more difficult to detect/debug than not creating the NVLINK2 devices so remove the possibly incorrect default behaviour.

  • Witherspoon: Fix VPD EEPROM type

    There are user-space tools that update the planar VPD via the sysfs interface. Currently we do not get correct information from hostboot about the exact type of the EEPROM so we need to manually fix it up here. This needs to be done as a platform specific fix since there is not standardised VPD EEPROM type.

IBM FSP Systems

  • nvram: Fix ‘missing’ nvram on FSP systems.

    commit ba4d46fdd9eb (“console: Set log level from nvram”) wants to read from NVRAM rather early. This works fine on BMC based systems as nvram_init() is actually synchronous. This is not true for FSP systems and it turns out that the query for the console log level simply queries blank nvram.

    The simple fix is to wait for the NVRAM read to complete before performing any query. Unfortunately it turns out that the fsp-nvram code does not inform the generic NVRAM layer when the read is complete, rather, it must be prompted to do so.

    This patch addresses both these problems. This patch adds a check before the first read of the NVRAM (for the console log level) that the read has completed. The fsp-nvram code has been updated to inform the generic layer as soon as the read completes.

    The old prompt to the fsp-nvram code has been removed but a check to ensure that the NVRAM has been loaded remains. It is conservative but if the NVRAM is not done loading before the host is booted it will not have an nvram device-tree node which means it won’t be able to access the NVRAM at all, ever, even after the NVRAM has loaded.


Since skiboot-5.10-rc1:

  • opal-prd: Fix FTBFS with -Werror=format-overflow

    i2c.c fails to compile with gcc7 and -Werror=format-overflow used in Debian Unstable and Ubuntu 18.04 :

    i2c.c: In function ‘i2c_init’:
    i2c.c:211:15: error: ‘%s’ directive writing up to 255 bytes into a
    region of size 236 [-Werror=format-overflow=]

Since skiboot-5.9:

  • Fix xscom-utils distclean target

    In Debian/Ubuntu, the packaging system likes to have a full clean-up that restores the tree back to original one, so add some files to the distclean target.

  • Add man pages for xscom-utils and pflash

    For the need of Debian/Ubuntu packaging, I inferred some initial man pages from their help output.


  • gard: Add tests

    I hear Stewart likes these for some reason. Dunno why.

  • gard: Add OpenBMC vPNOR support

    A big-ol-hack to add some checking for OpenBMC’s vPNOR GUARD files under /media/pnor-prsv. This isn’t ideal since it doesn’t handle the create case well, but it’s better than nothing.

  • gard: Always use MTD to access flash

    Direct mode is generally either unsafe or unsupported. We should always access the PNOR via an MTD device so make that the default. If someone really needs direct mode, then they can use pflash.

  • gard: Fix up do_create return values

    The return value of a subcommand is interpreted as a libflash error code when it’s positive or some subcommand specific error when negative. Currently the create subcommand always returns zero when exiting (even for errors) so fix that.

  • gard: Add usage message for -p

    The -p argument only really makes sense when -f is specified. Print an actual error message rather than just the usage blob.

  • gard: Fix max instance count

    There’s an entire byte for the instance count rather than a nibble. Only barf if the instance number is beyond 255 rather than 16.

  • gard: Fix up path parsing

    Currently we assume that the Unit ID can be used as an array index into the chip_units[] structure. There are holes in the ID space though, so this doesn’t actually work. Fix it up by walking the array looking for the ID.

  • gard: Set chip generation based on PVR

    Currently we assume that this tool is being used on a P8 system by default and allow the user to override this behaviour using the -8 and -9 command line arguments. When running on the host we can use the PVR to guess what chip generation so do that.

    This also changes the default behaviour to assume that the host is a P9 when running on an ARM system. This tool didn’t even work when compiled for ARM until recently and the OpenBMC vPNOR hack that we have currently is broken for P9 systems that don’t use vPNOR (Zaius and Romulus).

  • gard: Allow records with an ID of 0xffffffff

    We currently assume that a record with an ID of 0xffffffff is invalid. Apparently this is incorrect and we should display these records, so expand the check to compare the entire record with 0xff rather than just the ID.

  • gard: create: Allow creating arbitrary GARD records

    Add a new sub-command that allows us to create GARD records for arbitrary chip units. There isn’t a whole lot of constraints on this and that limits how useful it can be, but it does allow a user to GARD out individual DIMMs, chips or cores from the BMC (or host) if needed.

    There are a few caveats though:

    1. Not everything can, or should, have a GARD record applied it to.
    2. There is no validation that the unit actually exists. Doing that sort of validation requires something that understands the FAPI targeting information (I think) and adding support for it here would require some knowledge from the system XML file.
    3. There’s no way to get a list of paths in the system.
    4. Although we can create a GARD record at runtime it won’t be applied until the next IPL.
  • gard: Add path parsing support

    In order to support manual GARD records we need to be able to parse the hardware unit path strings. This patch implements that.

  • gard: list: Improve output

    Display the full path to the GARDed hardware unit in each record rather than relying on the output of gard show and convert do_list() to use the iterator while we’re here.

  • gard: {list, show}: Fix the Type field in the output

    The output of gard list has a field named “Type”, however this doesn’t actually indicate the type of the record. Rather, it shows the type of the path used to identify the hardware being GARDed. This is of pretty dubious value considering the Physical path seems to always be used when referring to GARDed hardware.

  • gard: Add P9 support

  • gard: Update chip unit data

    Source the list of units from the hostboot source rather than the previous hard coded list. The list of path element types changes between generations so we need to add a level of indirection to accommodate P9. This also changes the names used to match those printed by Hostboot at IPL time and paves the way to adding support for manual GARD record creation.

  • gard: show: Remove “Res Recovery” field

    This field has never been populated by hostboot on OpenPower systems so there’s no real point in reporting it’s contents.

libflash / pflash

Anybody shipping libflash or pflash to interact with POWER9 systems must upgrade to this version.

Since skiboot-5.10-rc2:

  • pflash: Fix makefile dependency issue

Since skiboot-5.9:

  • pflash: Support for volatile flag

    The volatile flag was added to the PNOR image to indicate partitions that are cleared during a host power off. Display this flag from the pflash command.

  • pflash: Support for clean_on_ecc_error flag

    Add the misc flag clear_on_ecc_error to libflash/pflash. This was the only missing flag. The generator of the virtual PNOR image relies on libflash/pflash to provide the partition information, so all flags are needed to build an accurate virtual PNOR partition table.

  • pflash: Respect write(2) return values

    The write(2) system call returns the number of bytes written, this is important since it is entitled to write less than what we requested. Currently we ignore the return value and assume it wrote everything we requested. While in practice this is likely to always be the case, it isn’t actually correct.

  • external/pflash: Fix erasing within a single erase block

    It is possible to erase within a single erase block. Currently the pflash code assumes that if the erase starts part way into an erase block it is because it needs to be aligned up to the boundary with the next erase block.

    Doing an erase smaller than a single erase block will cause underflows and looping forever on erase.

  • external/pflash: Fix non-zero return code for successful read when size%256 != 0

    When performing a read the return value from pflash is non-zero, even for a successful read, when the size being read is not a multiple of 256. This is because do_read_file returns the value from the write system call which is then returned by pflash. When the size is a multiple of 256 we get lucky in that this wraps around back to zero. However for any other value the return code is size % 256. This means even when the operation is successful the return code will seem to reflect an error.

    Fix this by returning zero if the entire size was read correctly, otherwise return the corresponding error code.

  • libflash: Fix parity calculation on ARM

    To calculate the ECC syndrome we need to calculate the parity of a 64bit number. On non-powerpc platforms we use the GCC builtin function __builtin_parityl() to do this calculation. This is broken on 32bit ARM where sizeof(unsigned long) is four bytes. Using __builtin_parityll() instead cures this.

  • libflash/mbox-flash: Add the ability to lock flash

  • libflash/mbox-flash: Understand v3

  • libflash/mbox-flash: Use BMC suggested timeout value

  • libflash/mbox-flash: Simplify message sending

    hw/lpc-mbox no longer requires that the memory associated with messages exist for the lifetime of the message. Once it has been sent to the BMC, that is bmc_mbox_enqueue() returns, lpc-mbox does not need the message to continue to exist. On the receiving side, lpc-mbox will ensure that a message exists for the receiving callback function.

    Remove all code to deal with allocating messages.

  • hw/lpc-mbox: Simplify message bookkeeping and timeouts

    Currently the hw/lpc-mbox layer keeps a pointer for the currently in-flight message for the duration of the mbox call. This creates problems when messages timeout, is that pointer still valid, what can we do with it. The memory is owned by the caller but if the caller has declared a timeout, it may have freed that memory.

    Another problem is locking. This patch also locks around sending and receiving to avoid races with timeouts and possible resends. There was some locking previously which was likely insufficient - definitely too hard to be sure is correct

    All this is made much easier with the previous rework which moves sequence number allocation and verification into lpc-mbox rather than the caller.

  • libflash/mbox-flash: Allow mbox-flash to tell the driver msg timeouts

    Currently when mbox-flash decides that a message times out the driver has no way of knowing to drop the message and will continue waiting for a response indefinitely preventing more messages from ever being sent.

    This is a problem if the BMC crashes or has some other issue where it won’t ever respond to our outstanding message.

    This patch provides a method for mbox-flash to tell the driver how long it should wait before it no longer needs to care about the response.

  • libflash/mbox-flash: Move sequence handling to driver level

  • libflash/mbox-flash: Always close windows before opening a new window

    The MBOX protocol states that if an open window command fails then all open windows are closed. Currently, if an open window command fails mbox-flash will erroneously assume that the previously open window is still open.

    The solution to this is to mark all windows as closed before issuing an open window command and then on success we’ll mark the new window as open.

  • libflash/mbox-flash: Add v2 error codes


Anybody shipping opal-prd for POWER9 systems must upgrade opal-prd to this new version.

  • prd: Log unsupported message type

    Useful for debugging.

    Sample output:

    [29155.157050283,7] PRD: Unsupported prd message type : 0xc
  • opal-prd: occ: Add support for runtime OCC load/start in ZZ

    This patch adds support to handle OCC load/start event from FSP/PRD. During IPL we send a success directly to FSP without invoking any HBRT load routines on receiving OCC load mbox message from FSP. At runtime we forward this event to host opal-prd.

    This patch provides support for invoking OCC load/start HBRT routines like load_pm_complex() and start_pm_complex() from opal-prd.

  • opal-prd: Add support for runtime OCC reset in ZZ

    This patch handles OCC_RESET runtime events in host opal-prd and also provides support for calling ‘hostinterface->wakeup()’ which is required for doing the reset operation.

  • prd: Enable error logging via firmware_request interface

    In P9 HBRT sends error logs to FSP via firmware_request interface. This patch adds support to parse error log and send it to FSP.

  • prd: Add generic response structure inside prd_fw_msg

    This patch adds generic response structure. Also sync prd_fw_msg type macros with hostboot.

  • opal-prd: flush after logging to stdio in debug mode

    When in debug mode, flush after each log output. This makes it more likely that we’ll catch failure reasons on severe errors.

Debugging and reliability improvements

Since skiboot-5.10-rc3:

  • increase log verbosity in debug builds
  • Add -debug to version on DEBUG builds
  • cpu_wait_job: Correctly report time spent waiting for job

Since skiboot-5.10-rc2:

  • ATTN: Enable flush instruction cache bit in HID register

    In P9, we have to enable “flush the instruction cache” bit along with “attn instruction support” bit to trigger attention.

Since skiboot-5.10-rc1:

  • core/init: manage MSR[ME] explicitly, always enable

    The current boot sequence inherits MSR[ME] from the IPL firmware, and never changes it. Some environments disable MSR[ME] (e.g., mambo), and others can enable it (hostboot).

    This has two problems. First, MSR[ME] must be disabled while in the process of taking over the interrupt vector from the previous environment. Second, after installing our machine check handler, MSR[ME] should be enabled to get some useful output rather than a checkstop.

  • core/exception: beautify exception handler, add MCE-involved registers

    Print DSISR and DAR, to help with deciphering machine check exceptions, and improve the output a bit, decode NIP symbol, improve alignment, etc. Also print a specific header for machine check, because we do expect to see these if there is a hardware failure.


    [    0.005968779,3] ***********************************************
    [    0.005974102,3] Unexpected exception 200 !
    [    0.005978696,3] SRR0 : 000000003002ad80 SRR1 : 9000000000001000
    [    0.005985239,3] HSRR0: 00000000300027b4 HSRR1: 9000000030001000
    [    0.005991782,3] LR   : 000000003002ad80 CTR  : 0000000000000000
    [    0.005998130,3] CFAR : 00000000300b58bc
    [    0.006002769,3] CR   : 40000004  XER: 20000000
    [    0.006008069,3] GPR00: 000000003002ad80 GPR16: 0000000000000000
    [    0.006015170,3] GPR01: 0000000031c03bd0 GPR17: 0000000000000000


    [    0.003287941,3] ***********************************************
    [    0.003561769,3] Fatal MCE at 000000003002ad80   .nvram_init+0x24
    [    0.003579628,3] CFAR : 00000000300b5964
    [    0.003584268,3] SRR0 : 000000003002ad80 SRR1 : 9000000000001000
    [    0.003590812,3] HSRR0: 00000000300027b4 HSRR1: 9000000030001000
    [    0.003597355,3] DSISR: 00000000         DAR  : 0000000000000000
    [    0.003603480,3] LR   : 000000003002ad68 CTR  : 0000000030093d80
    [    0.003609930,3] CR   : 40000004         XER  : 20000000
    [    0.003615698,3] GPR00: 00000000300149e8 GPR16: 0000000000000000
    [    0.003622799,3] GPR01: 0000000031c03bc0 GPR17: 0000000000000000

Since skiboot-5.9:

  • lock: Add additional lock auditing code

    Keep track of lock owner name and replace lock_depth counter with a per-cpu list of locks held by the cpu.

    This allows us to print the actual locks held in case we hit the (in)famous message about opal_pollers being run with a lock held.

    It also allows us to warn (and drop them) if locks are still held when returning to the OS or completing a scheduled job.

  • Add support for new GCC 7 parametrized stack protector

    This gives us per-cpu guard values as well. For now I just XOR a magic constant with the CPU PIR value.

  • Mambo: run hello_world and sreset_world tests with Secure and Trusted Boot

    We disable the secure boot part, but we keep the verified boot part as we don’t currently have container verification code for Mambo.

    We can run a small part of the code currently though.

  • core/flash.c: extern function to get the name of a PNOR partition

    This adds the flash_map_resource_name() to allow skiboot subsystems to lookup the name of a PNOR partition. Thus, we don’t need to duplicate the same information in other places (e.g. libstb).

  • libflash/mbox-flash: only wait for MBOX_DEFAULT_POLL_MS if busy

    This makes the mbox unit test run 300x quicker and seems to shave about 6 seconds from boot time on Witherspoon.

  • make check: Make valgrind optional

    To (slightly) lower the barrier for contributions, we can make valgrind optional with just a small amount of plumbing.

    This allows make check to run successfully without valgrind.

  • libflash/test: Add tests for mbox-flash

    A first basic set of tests for mbox-flash. These tests do their testing by stubbing out or otherwise replacing functions not in libflash/mbox-flash.c. The stubbed out version of the function can then be used to emulate a BMC mbox daemon talking to back to the code in mbox-flash and it can ensure that there is some adherence to the protocol and that from a block-level api point of view the world appears sane.

    This makes these tests simple to run and they have been integrated into make check. The down side is that these tests rely on duplicated feature incomplete BMC daemon behaviour. Therefore these tests are a strong indicator of broken behaviour but a very unreliable indicator of correctness.

    Full integration tests with a ‘real’ BMC daemon are probably beyond the scope of this repository.

  • external/test/ fix VERSION substitution when no tags

    i.e. we get a hash rather than a version number

    This seems to be occurring in Travis if it doesn’t pull a tag.

  • external/test: make stripping out version number more robust

    For some bizarre reason, Travis started failing on this substitution when there’d been zero code changes in this area… This at least papers over whatever the problem is for the time being.

  • io: Add load_wait() helper

    This uses the standard form twi/isync pair to ensure a load is consumed by the core before continuing. This can be necessary under some circumstances for example when having the following sequence:

    • Store reg A
    • Load reg A (ensure above store pushed out)
    • delay loop
    • Store reg A

    I.E., a mandatory delay between 2 stores. In theory the first store is only guaranteed to reach the device after the load from the same location has completed. However the processor will start executing the delay loop without waiting for the return value from the load.

    This construct enforces that the delay loop isn’t executed until the load value has been returned.

  • chiptod: Keep boot timestamps contiguous

    Currently we reset the timebase value to (almost) zero when synchronising the timebase of each chip to the Chip TOD network which results in this:

    [   42.374813167,5] CPU: All 80 processors called in...
    [    2.222791151,5] FLASH: Found system flash: Macronix MXxxL51235F id:0
    [    2.222977933,5] BT: Interface initialized, IO 0x00e4

    This patch modifies the chiptod_init() process to use the current timebase value rather than resetting it to zero. This results in the timestamps remaining contiguous from the start of hostboot until the petikernel starts. e.g.

    [   70.188811484,5] CPU: All 144 processors called in...
    [   72.458004252,5] FLASH: Found system flash:  id:0
    [   72.458147358,5] BT: Interface initialized, IO 0x00e4
  • hdata/spira: Add missing newline to prlog() call

    We’re missing a n here.

  • opal/xscom: Add recovery for lost core wakeup SCOM failures.

    Due to a hardware issue where core responding to SCOM was delayed due to thread reconfiguration, leaves the SCOM logic in a state where the subsequent SCOM to that core can get errors. This is affected for Core PC SCOM registers in the range of 20010A80-20010ABF

    The solution is if a xscom timeout occurs to one of Core PC SCOM registers in the range of 20010A80-20010ABF, a clearing SCOM write is done to 0x20010800 with data of ‘0x00000000’ which will also get a timeout but clears the SCOM logic errors. After the clearing write is done the original SCOM operation can be retried.

    The SCOM timeout is reported as status 0x4 (Invalid address) in HMER[21-23].

  • opal/xscom: Move the delay inside xscom_reset() function.

    So caller of xscom_reset() does not have to bother about adding a delay separately. Instead caller can control whether to add a delay or not using second argument to xscom_reset().

  • timer: Stop calling list_top() racily

    This will trip the debug checks in debug builds under some circumstances and is actually a rather bad idea as we might look at a timer that is concurrently being removed and modified, and thus incorrectly assume there is no work to do.

  • fsp: Bail out of HIR if FSP is resetting voluntarily

    1. Surveillance response times out and OPAL triggers a HIR
    2. Before the HIR process kicks in, OPAL gets a PSI interrupt indicating link down
    3. HIR process continues and OPAL tries to write to DRCR; PSI link inactive => xstop

    OPAL should confirm that the FSP is not already in reset in the HIR path.

  • sreset_kernel: only run SMT tests due to not supporting re-entry

  • Use systemsim-p9 v1.1

  • direct-controls: enable fast reboot direct controls for mambo

    Add mambo direct controls to stop threads, which is required for reliable fast-reboot. Enable direct controls by default on mambo.

  • core/opal: always verify cpu->pir on entry

  • asm/head: add entry/exit calls

    Add entry and exit C functions that can do some more complex checks before the opal proper call. This requires saving off volatile registers that have arguments in them.

  • core/lock: improve bust_locks

    Prevent try_lock from modifying the lock state when bust_locks is set. unlock will not unlock it in that case, so locks will get taken and never released while bust_locks is set.

  • hw/occ: Log proper SCOM register names

    This patch fixes the logging of incorrect SCOM register names.

  • mambo: Add support for NUMA

    Currently the mambo scripts can do multiple chips, but only the first ever has memory.

    This patch adds support for having memory on each chip, with each appearing as a separate NUMA node. Each node gets MEM_SIZE worth of memory.

    It’s opt-in, via export MAMBO_NUMA=1.

  • external/mambo: Switch qtrace command to use plug-ins

    The plug-in seems to be the preferred way to do this now, it works better, and the qtracer emitter seems to generate invalid traces in new mambo versions.

  • asm/head: Loop after attn

    We use the attn instruction to raise an error in early boot if OPAL don’t recognise the PVR. It’s possible for hostboot to disable the attn instruction before entering OPAL so add an extra busy loop after the attn to prevent attempting to boot on an unknown processor.


  • 302 csets from 32 developers
  • 3 employers found
  • A total of 15919 lines added, 4786 removed (delta 11133)

Extending the analysis done for some previous releases, we can see our trends in code review across versions:

Release csets Ack % Reviews % Tested % Reported %
5.0 329 15 (5%) 20 (6%) 1 (0%) 0 (0%)
5.1 372 13 (3%) 38 (10%) 1 (0%) 4 (1%)
5.2-rc1 334 20 (6%) 34 (10%) 6 (2%) 11 (3%)
5.3-rc1 302 36 (12%) 53 (18%) 4 (1%) 5 (2%)
5.4 361 16 (4%) 28 (8%) 1 (0%) 9 (2%)
5.5 408 11 (3%) 48 (12%) 14 (3%) 10 (2%)
5.6 87 12 (14%) 6 (7%) 5 (6%) 2 (2%)
5.7 232 30 (13%) 32 (14%) 5 (2%) 2 (1%)
5.8 157 13 (8%) 36 (23%) 2 (1%) 6 (4%)
5.9 209 15 (7%) 78 (37%) 3 (1%) 10 (5%)
5.10 302 20 (6%) 62 (21%) 24 (8%) 11 (4%)

The review count for v5.9 is largely bogus, there was a series of 25 whitespace patches that got “Reviewed-by” and if we exclude them, we’re back to 14%, which is more like what I’d expect.

For 5.10, We’ve seen an increase in Reviewed-by from 5.9, back to closer to 5.8 levels. I’m hoping we can keep the ~20% up.

Initially I was really pleased with the increase in Tested-by, but with closer examination, 17 of those are actually from various automated testing on commits to code we bring in from hostboot/other firmware components. When you exclude them, we’re back down to 2% getting Tested-by, which isn’t great.

Developers with the most changesets

Developer # %
Stewart Smith 40 (13.2%)
Nicholas Piggin 37 (12.3%)
Oliver O’Halloran 36 (11.9%)
Benjamin Herrenschmidt 23 (7.6%)
Claudio Carvalho 20 (6.6%)
Cyril Bur 19 (6.3%)
Michael Neuling 13 (4.3%)
Shilpasri G Bhat 12 (4.0%)
Reza Arbab 12 (4.0%)
Pridhiviraj Paidipeddi 11 (3.6%)
Vasant Hegde 10 (3.3%)
Akshay Adiga 10 (3.3%)
Mahesh Salgaonkar 8 (2.6%)
Russell Currey 7 (2.3%)
Alistair Popple 7 (2.3%)
Vaibhav Jain 5 (1.7%)
Prem Shanker Jha 4 (1.3%)
Robert Lippert 4 (1.3%)
Frédéric Bonnard 3 (1.0%)
Christophe Lombard 3 (1.0%)
Jeremy Kerr 2 (0.7%)
Michael Ellerman 2 (0.7%)
Balbir Singh 2 (0.7%)
Andrew Donnellan 2 (0.7%)
Madhavan Srinivasan 2 (0.7%)
Adriana Kobylak 2 (0.7%)
Sukadev Bhattiprolu 1 (0.3%)
Alexey Kardashevskiy 1 (0.3%)
Frederic Barrat 1 (0.3%)
Ananth N Mavinakayanahalli 1 (0.3%)
Suraj Jitindar Singh 1 (0.3%)
Guilherme G. Piccoli 1 (0.3%)

Developers with the most changed lines

Developer # %
Stewart Smith 4284 (24.5%)
Nicholas Piggin 2924 (16.7%)
Claudio Carvalho 2476 (14.2%)
Shilpasri G Bhat 1490 (8.5%)
Cyril Bur 1475 (8.4%)
Oliver O’Halloran 1242 (7.1%)
Benjamin Herrenschmidt 736 (4.2%)
Alistair Popple 498 (2.8%)
Vasant Hegde 299 (1.7%)
Akshay Adiga 273 (1.6%)
Reza Arbab 231 (1.3%)
Mahesh Salgaonkar 225 (1.3%)
Balbir Singh 213 (1.2%)
Frédéric Bonnard 169 (1.0%)
Michael Neuling 142 (0.8%)
Robert Lippert 97 (0.6%)
Pridhiviraj Paidipeddi 93 (0.5%)
Prem Shanker Jha 92 (0.5%)
Christophe Lombard 80 (0.5%)
Russell Currey 78 (0.4%)
Michael Ellerman 72 (0.4%)
Adriana Kobylak 71 (0.4%)
Madhavan Srinivasan 61 (0.3%)
Sukadev Bhattiprolu 58 (0.3%)
Vaibhav Jain 52 (0.3%)
Jeremy Kerr 27 (0.2%)
Ananth N Mavinakayanahalli 16 (0.1%)
Frederic Barrat 9 (0.1%)
Andrew Donnellan 5 (0.0%)
Alexey Kardashevskiy 3 (0.0%)
Suraj Jitindar Singh 1 (0.0%)
Guilherme G. Piccoli 1 (0.0%)

Developers with the most lines removed

Developer # %
Alistair Popple 304 (6.4%)
Andrew Donnellan 1 (0.0%)

Developers with the most signoffs

Developer # %
Stewart Smith 262 (99.2%)
Reza Arbab 1 (0.4%)
Mahesh Salgaonkar 1 (0.4%)

Developers with the most reviews

Developer # %
Andrew Donnellan 8 (13.6%)
Balbir Singh 5 (8.5%)
Vasant Hegde 5 (8.5%)
Gregory S. Still 4 (6.8%)
Nicholas Piggin 4 (6.8%)
Reza Arbab 3 (5.1%)
Alistair Popple 3 (5.1%)
Jennifer A. Stofer 3 (5.1%)
Oliver O’Halloran 3 (5.1%)
Vaidyanathan Srinivasan 2 (3.4%)
Hostboot Team 2 (3.4%)
Christian R. Geddes 2 (3.4%)
Frederic Barrat 2 (3.4%)
Cyril Bur 2 (3.4%)
Stewart Smith 1 (1.7%)
Cédric Le Goater 1 (1.7%)
Samuel Mendoza-Jonas 1 (1.7%)
Daniel M. Crowell 1 (1.7%)
Vaibhav Jain 1 (1.7%)
Madhavan Srinivasan 1 (1.7%)
Michael Ellerman 1 (1.7%)
Shilpasri G Bhat 1 (1.7%)
Total 59 (100%)

Developers with the most test credits

Developer # %
FSP CI Jenkins 4 (16.7%)
Jenkins Server 4 (16.7%)
Hostboot CI 4 (16.7%)
Oliver O’Halloran 3 (12.5%)
Jenkins OP Build CI 3 (12.5%)
Jenkins OP HW 2 (8.3%)
Pridhiviraj Paidipeddi 2 (8.3%)
Andrew Donnellan 1 (4.2%)
Vaidyanathan Srinivasan 1 (4.2%)
Total 24 (100%)

Developers who gave the most tested-by credits

Developer # %
Prem Shanker Jha 17 (70.8%)
Benjamin Herrenschmidt 3 (12.5%)
Stewart Smith 2 (8.3%)
Shilpasri G Bhat 1 (4.2%)
Ananth N Mavinakayanahalli 1 (4.2%)
Total 24 (100%)

Developers with the most report credits

Developer # %
Pridhiviraj Paidipeddi 2 (18.2%)
Benjamin Herrenschmidt 1 (9.1%)
Andrew Donnellan 1 (9.1%)
Michael Ellerman 1 (9.1%)
Deb McLemore 1 (9.1%)
Brad Bishop 1 (9.1%)
Michel Normand 1 (9.1%)
Hugo Landau 1 (9.1%)
Minda Wei 1 (9.1%)
Francesco A Campisano 1 (9.1%)
Total 11 (100%)

Developers who gave the most report credits

Developer # %
Stewart Smith 7 (63.6%)
Suraj Jitindar Singh 1 (9.1%)
Jeremy Kerr 1 (9.1%)
Michael Neuling 1 (9.1%)
Frédéric Bonnard 1 (9.1%)
Total 11 (100%)

Changesets and Employers

Top changeset contributors by employer:

Employer # %
IBM 298 (98.7%)
Google 3 (1.0%)
(Unknown) 1 (0.3%)

Top lines changed by employer:

Employer # %
IBM 17396 (99.4%)
Google 73 (0.4%)
(Unknown) 24 (0.1%)

Employers with the most signoffs (total 264):

Employer # %
IBM 264 (100.0%)

Employers with the most hackers (total 33)

Employer # %
IBM 31 (93.9%)
Google 1 (3.0%)
(Unknown) 1 (3.0%)