skiboot v6.2.1 release notes

Signed-off-by: Stewart Smith <stewart@linux.ibm.com>
(cherry picked from commit 0647f2a)
Signed-off-by: Stewart Smith <stewart@linux.ibm.com>

doc/release-notes/skiboot-6.2.1.rst

@@ -0,0 +1,83 @@
+.. _skiboot-6.2.1:
+
+=============
+skiboot-6.2.1
+=============
+
+skiboot 6.2.1 was released on Wednesday February 20th, 2019. It replaces
+:ref:`skiboot-6.2` as the current stable release in the 6.2.x series.
+
+It is recommended that 6.2.1 be used instead of any previous 6.2.x version
+due to the bug fixes it contains.
+
+Bug fixes included in this release are:
+
+- libflash/ecc: Fix compilation warning with gcc9
+
+  Fixes: https://github.com/open-power/skiboot/issues/218
+
+- core/opal: Print PIR value in exit path, useful for debugging
+- core/ipmi: Improve error message
+- firmware-versions: Add test case for parsing VERSION
+
+  If we hit a entry in VERSION that is larger than our
+  buffer size, we skip over it gracefully rather than overwriting the
+  stack. This is only a problem if VERSION isn't trusted, which as of
+  4b8cc05a94513816d43fb8bd6178896b430af08f it is verified as part of
+  Secure Boot.
+- core/cpu: HID update race
+
+  If the per-core HID register is updated concurrently by multiple
+  threads, updates can get lost. This has been observed during fast
+  reboot where the HILE bit does not get cleared on all cores, which
+  can cause machine check exception interrupts to crash.
+
+  Fix this by only updating HID on thread0.
+- cpufeatures: Always advertise POWER8NVL as DD2
+
+  Despite the major version of PVR being 1 (0x004c0100) for POWER8NVL,
+  these chips are functionally equalent to P8/P8E DD2 levels.
+
+  This advertises POWER8NVL as DD2. As the result, skiboot adds
+  ibm,powerpc-cpu-features/processor-control-facility for such CPUs and
+  the linux kernel can use hypervisor doorbell messages to wake secondary
+  threads; otherwise "KVM: CPU %d seems to be stuck" would appear because
+  of missing LPCR_PECEDH.
+- p9dsu: Fix p9dsu slot tables
+
+  Set the attributes on the slot tables to account for
+  builtin or pluggable etypes, this will allow pci
+  enumeration to calculate subordinate buses.
+
+  Update some slot label strings.
+
+  Add WIO Slot5 which is standard on the ESS config.
+- core/lock: Stop drop_my_locks() from always causing abort
+
+  The loop in drop_my_locks() looks like this: ::
+
+            while((l = list_pop(&this_cpu()->locks_held, struct lock, list)) != NULL) {
+                    if (warn)
+                            prlog(PR_ERR, "  %s\n", l->owner);
+                    unlock(l);
+            }
+
+  Both list_pop() and unlock() call list_del(). This means that on the
+  last iteration of the loop, the list will be empty when we get to
+  unlock_check(), causing this: ::
+
+      LOCK ERROR: Releasing lock we don't hold depth @0x30493d20 (state: 0x0000000000000001)
+      [13836.000173140,0] Aborting!
+      CPU 0000 Backtrace:
+       S: 0000000031c03930 R: 000000003001d840   ._abort+0x60
+       S: 0000000031c039c0 R: 000000003001a0c4   .lock_error+0x64
+       S: 0000000031c03a50 R: 0000000030019c70   .unlock+0x54
+       S: 0000000031c03af0 R: 000000003001a040   .drop_my_locks+0xf4
+
+  To fix this, change list_pop() to list_top().
+- p9dsu: Fix p9dsu default variant
+
+  Add the default when no riser_id is returned from the ipmi query.
+
+  Allow a little more time for BMC reply and cleanup some label strings.
+