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Oliver O'Halloran 98ba956f6a powerpc/pseries/eeh: Rework device EEH PE determination
The process Linux uses for determining if a device supports EEH or not
appears to be at odds with what PAPR says the OS should be doing. The
current flow is something like:

1. Assume pe_config_addr is equal the the device's config_addr.
2. Attempt to enable EEH on that PE
3. Verify EEH was enabled (POWER4 bug workaround)
4. Try find the pe_config_addr using the ibm,get-config-addr-info2 RTAS
   call.
5. If that fails walk the pci_dn tree upwards trying to find a parent
   device with EEH support. If we find one then add the device to that PE.

The first major problem with this process is that we need the PE config
address in step 2) since its needs to be passed to the ibm,set-eeh-option
RTAS call when enabling EEH for th PE. We hack around this requirement in
by making the assumption in 1) and delay finding the actual PE address
until 4). This is fine if:

a) The PCI device is the 0th function, and
b) The device is on the PE's root bus.

Granted, the current sequence does appear to work on most systems even when
these conditions are false. At a guess PowerVM's RTAS has workarounds to
accommodate Linux's quirks or the RTAS call to enable EEH is treated as
no-op on most platforms since EEH is usually enabled by default. However,
what is currently implemented is a bit sketch and is downright confusing
since it doesn't match up with what what PAPR suggests we should be doing.

This patch re-works how we handle EEH init so that we find the PE config
address using the ibm,get-config-addr-info2 RTAS call first, then use the
found address to finish the EEH init process. It also drops the Power4
workaround since as of commit 471d7ff8b5 ("powerpc/64s: Remove POWER4
support") the kernel does not support running on a Power4 CPU so there's
no need to support the Power4 platform's quirks either. With the patch
applied the sequence is now:

1. Find the pe_config_addr from the device using the RTAS call.
2. Enable the PE.
3. Insert the edev into the tree and create an eeh_pe if needed.

The other change made here is ignoring unsupported devices entirely.
Currently the device's BARs are saved to the eeh_dev even if the device is
not part of an EEH PE. Not being part of a PE means that an EEH recovery
pass will never see that device so the saving the BARs is pointless.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200918093050.37344-7-oohall@gmail.com
2020-10-06 23:22:25 +11:00
Documentation powerpc/watchpoint/ptrace: Introduce PPC_DEBUG_FEATURE_DATA_BP_ARCH_31 2020-09-15 22:13:20 +10:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
arch powerpc/pseries/eeh: Rework device EEH PE determination 2020-10-06 23:22:25 +11:00
block block-5.9-2020-08-14 2020-08-15 20:36:42 -07:00
certs .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2020-08-14 13:09:15 -07:00
drivers serial: pmac_zilog: use for_each_child_of_node() macro 2020-09-18 19:59:44 +10:00
fs mm: fix exec activate_mm vs TLB shootdown and lazy tlb switching race 2020-09-16 12:24:31 +10:00
include sched/topology: Allow archs to override cpu_smt_mask 2020-09-16 22:05:18 +10:00
init OpenRISC updates for 5.9 2020-08-14 14:04:53 -07:00
ipc ipc/shm.c: remove the superfluous break 2020-08-12 10:58:02 -07:00
kernel A single bug fix for the common entry code. The transcript of the x86 2020-08-23 11:05:47 -07:00
lib lib/string.c: Use freestanding environment 2020-08-19 11:23:45 -07:00
mm Merge branch 'fixes' into next 2020-09-14 22:57:18 +10:00
net net: nexthop: don't allow empty NHA_GROUP 2020-08-22 12:39:55 -07:00
samples Kbuild updates for v5.9 2020-08-09 14:10:26 -07:00
scripts kconfig: qconf: replace deprecated QString::sprintf() with QTextStream 2020-08-21 10:23:38 +09:00
security Merge branch 'akpm' (patches from Andrew) 2020-08-12 11:24:12 -07:00
sound sound fixes for 5.9-rc2 2020-08-21 10:07:54 -07:00
tools selftests/powerpc: Tests for kernel accessing user memory 2020-09-15 22:13:21 +10:00
usr Merge branch 'work.fdpic' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-08-07 13:29:39 -07:00
virt * PAE and PKU bugfixes for x86 2020-08-22 10:03:05 -07:00
.clang-format block: add bio_for_each_bvec_all() 2020-05-25 11:25:24 +02:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: Add ZSTD-compressed files 2020-07-31 11:50:49 +02:00
.mailmap Merge branch 'akpm' (patches from Andrew) 2020-08-21 14:44:48 -07:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS CREDITS: Replace HTTP links with HTTPS ones 2020-07-23 14:53:58 -06:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS MAINTAINERS: Update Mellanox and Cumulus Network addresses to new domain 2020-08-21 10:48:48 -03:00
Makefile Linux 5.9-rc2 2020-08-23 14:08:43 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.