powerpc: Remove now superfluous sentinel element from ctl_table arrays

This commit comes at the tail end of a greater effort to remove the
empty elements at the end of the ctl_table arrays (sentinels) which
will reduce the overall build time size of the kernel and run time
memory bloat by ~64 bytes per sentinel (further information Link :
https://lore.kernel.org/all/ZO5Yx5JFogGi%2FcBo@bombadil.infradead.org/)

Remove sentinel from powersave_nap_ctl_table and nmi_wd_lpm_factor_ctl_table.
This removal is safe because register_sysctl implicitly uses ARRAY_SIZE()
in addition to checking for the sentinel.

Signed-off-by: Joel Granados <j.granados@samsung.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>

powerpc: Include asm/nmi.c in mobility.c for watchdog_hardlockup_set_timeout_pct()

The powerpc/platforms/pseries/mobility.c calls
watchdog_hardlockup_set_timeout_pct(), which is declared in
<asm/nmi.h>. We used to automatically get <asm/nmi.h> included, but
that changed as of commit 7ca8fe94aa92 ("watchdog/hardlockup: define
HARDLOCKUP_DETECTOR_ARCH"). Let's add the explicit include.

Reported-by: Randy Dunlap <rdunlap@infradead.org>
Closes: https://lore.kernel.org/r/af19b76d-aa4b-6c88-9cac-eae4b2072497@infradead.org
Fixes: 7ca8fe94aa92 ("watchdog/hardlockup: define HARDLOCKUP_DETECTOR_ARCH")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org> # build-tested
Reviewed-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230629124500.1.I55e2f4e7903d686c4484cb23c033c6a9e1a9d4c4@changeid

watchdog/hardlockup: rename some "NMI watchdog" constants/function

Do a search and replace of:
- NMI_WATCHDOG_ENABLED => WATCHDOG_HARDLOCKUP_ENABLED
- SOFT_WATCHDOG_ENABLED => WATCHDOG_SOFTOCKUP_ENABLED
- watchdog_nmi_ => watchdog_hardlockup_
- nmi_watchdog_available => watchdog_hardlockup_available
- nmi_watchdog_user_enabled => watchdog_hardlockup_user_enabled
- soft_watchdog_user_enabled => watchdog_softlockup_user_enabled
- NMI_WATCHDOG_DEFAULT => WATCHDOG_HARDLOCKUP_DEFAULT

Then update a few comments near where names were changed.

This is specifically to make it less confusing when we want to introduce
the buddy hardlockup detector, which isn't using NMIs. As part of this,
we sanitized a few names for consistency.

[trix@redhat.com: make variables static]
Link: https://lkml.kernel.org/r/20230525162822.1.I0fb41d138d158c9230573eaa37dc56afa2fb14ee@changeid
Link: https://lkml.kernel.org/r/20230519101840.v5.12.I91f7277bab4bf8c0cb238732ed92e7ce7bbd71a6@changeid
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Tom Rix <trix@redhat.com>
Reviewed-by: Tom Rix <trix@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chen-Yu Tsai <wens@csie.org>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Colin Cross <ccross@android.com>
Cc: Daniel Thompson <daniel.thompson@linaro.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Guenter Roeck <groeck@chromium.org>
Cc: Ian Rogers <irogers@google.com>
Cc: Lecopzer Chen <lecopzer.chen@mediatek.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Masayoshi Mizuma <msys.mizuma@gmail.com>
Cc: Matthias Kaehlcke <mka@chromium.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Pingfan Liu <kernelfans@gmail.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: "Ravi V. Shankar" <ravi.v.shankar@intel.com>
Cc: Ricardo Neri <ricardo.neri@intel.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Stephen Boyd <swboyd@chromium.org>
Cc: Sumit Garg <sumit.garg@linaro.org>
Cc: Tzung-Bi Shih <tzungbi@chromium.org>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

driver core: class: mark the struct class for sysfs callbacks as constant

struct class should never be modified in a sysfs callback as there is
nothing in the structure to modify, and frankly, the structure is almost
never used in a sysfs callback, so mark it as constant to allow struct
class to be moved to read-only memory.

While we are touching all class sysfs callbacks also mark the attribute
as constant as it can not be modified. The bonding code still uses this
structure so it can not be removed from the function callbacks.

Cc: "David S. Miller" <davem@davemloft.net>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Bartosz Golaszewski <brgl@bgdev.pl>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: Namjae Jeon <linkinjeon@kernel.org>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Russ Weight <russell.h.weight@intel.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Steve French <sfrench@samba.org>
Cc: Vignesh Raghavendra <vigneshr@ti.com>
Cc: linux-cifs@vger.kernel.org
Cc: linux-gpio@vger.kernel.org
Cc: linux-mtd@lists.infradead.org
Cc: linux-rdma@vger.kernel.org
Cc: linux-s390@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: netdev@vger.kernel.org
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Link: https://lore.kernel.org/r/20230325084537.3622280-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

powerpc: Simplify sysctl registration for nmi_wd_lpm_factor_ctl_table

There is no need to declare an extra tables to just create directory,
this can be easily be done with a prefix path with register_sysctl().

Simplify this registration.

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230310232850.3960676-3-mcgrof@kernel.org

powerpc/rtas: arch-wide function token lookup conversions

With the tokens for all implemented RTAS functions now available via
rtas_function_token(), which is optimal and safe for arbitrary
contexts, there is no need to use rtas_token() or cache its result.

Most conversions are trivial, but a few are worth describing in more
detail:

* Error injection token comparisons for lockdown purposes are
consolidated into a simple predicate: token_is_restricted_errinjct().

* A couple of special cases in block_rtas_call() do not use
rtas_token() but perform string comparisons against names in the
function table. These are converted to compare against token values
instead, which is logically equivalent but less expensive.

* The lookup for the ibm,os-term token can be deferred until needed,
instead of caching it at boot to avoid device tree traversal during
panic.

* Since rtas_function_token() accesses a read-only data structure
without taking any locks, xmon's lookup of set-indicator can be
performed as needed instead of cached at startup.

Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20230125-b4-powerpc-rtas-queue-v3-20-26929c8cce78@linux.ibm.com

powerpc/pseries: reset the RCU watchdogs after a LPM

The RCU watchdog timer should be reset when restarting the CPU after a
Live Partition Mobility operation.

Signed-off-by: Laurent Dufour <ldufour@linux.ibm.com>
Acked-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Combine comments into a single comment block]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20221125173204.15329-1-ldufour@linux.ibm.com

powerpc/pseries: Move vas_migration_handler early during migration

When the migration is initiated, the hypervisor changes VAS
mappings as part of pre-migration event. Then the OS gets the
migration event which closes all VAS windows before the migration
starts. NX generates continuous faults until windows are closed
and the user space can not differentiate these NX faults coming
from the actual migration. So to reduce this time window, close
VAS windows first in pseries_migrate_partition().

Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Reviewed-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/d8efade91dda831c9ed4abb226dab627da594c5f.camel@linux.ibm.com

powerpc/mobility: fix repeated words in comments

Delete the redundant word 'the'.

Signed-off-by: Jilin Yuan <yuanjilin@cdjrlc.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220831005109.38314-1-yuanjilin@cdjrlc.com

powerpc/pseries/mobility: set NMI watchdog factor during an LPM

During an LPM, while the memory transfer is in progress on the arrival
side, some latencies are generated when accessing not yet transferred
pages on the arrival side. Thus, the NMI watchdog may be triggered too
frequently, which increases the risk to hit an NMI interrupt in a bad
place in the kernel, leading to a kernel panic.

Disabling the Hard Lockup Watchdog until the memory transfer could be a
too strong work around, some users would want this timeout to be
eventually triggered if the system is hanging even during an LPM.

Introduce a new sysctl variable nmi_watchdog_factor. It allows to apply
a factor to the NMI watchdog timeout during an LPM. Just before the CPUs
are stopped for the switchover sequence, the NMI watchdog timer is set
to watchdog_thresh + factor%

A value of 0 has no effect. The default value is 200, meaning that the
NMI watchdog is set to 30s during LPM (based on a 10s watchdog_thresh
value). Once the memory transfer is achieved, the factor is reset to 0.

Setting this value to a high number is like disabling the NMI watchdog
during an LPM.

Signed-off-by: Laurent Dufour <ldufour@linux.ibm.com>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220713154729.80789-5-ldufour@linux.ibm.com

powerpc/mobility: wait for memory transfer to complete

In pseries_migration_partition(), loop until the memory transfer is
complete. This way the calling drmgr process will not exit earlier,
allowing callbacks to be run only once the migration is fully completed.

If reading the VASI state is done after the hypervisor has completed the
migration, the HCALL is returning H_PARAMETER. We can safely assume that
the memory transfer is achieved if this happens.

This will also allow to manage the NMI watchdog state in the next commits.

Signed-off-by: Laurent Dufour <ldufour@linux.ibm.com>
Reviewed-by: Nathan Lynch <nathanl@linux.ibm.com>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220713154729.80789-2-ldufour@linux.ibm.com

powerpc/pseries/vas: Add VAS migration handler

Since the VAS windows belong to the VAS hardware resource, the
hypervisor expects the partition to close them on source partition
and reopen them after the partition migrated on the destination
machine.

This handler is called before pseries_suspend() to close these
windows and again invoked after migration. All active windows
for both default and QoS types will be closed and mark them
inactive and reopened after migration with this handler.
During the migration, the user space receives paste instruction
failure if it issues copy/paste on these inactive windows.

The current migration implementation does not freeze the user
space and applications can continue to open VAS windows while
migration is in progress. So when the migration_in_progress flag
is set, VAS open window API returns -EBUSY.

Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/05e45ff4f8babd2490ccb7ae923884f4aa21a7e5.camel@linux.ibm.com

powerpc/pseries: make pseries_devicetree_update() static

pseries_devicetree_update() has only one call site, in the same file in
which it is defined. Make it static.

Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220207221247.354454-1-nathanl@linux.ibm.com

powerpc/64s: Move hash MMU support code under CONFIG_PPC_64S_HASH_MMU

Compiling out hash support code when CONFIG_PPC_64S_HASH_MMU=n saves
128kB kernel image size (90kB text) on powernv_defconfig minus KVM,
350kB on pseries_defconfig minus KVM, 40kB on a tiny config.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Fixup defined(ARCH_HAS_MEMREMAP_COMPAT_ALIGN), which needs CONFIG.
Fix radix_enabled() use in setup_initial_memory_limit(). Add some
stubs to reduce number of ifdefs.]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211201144153.2456614-18-npiggin@gmail.com

powerpc/pseries/mobility: ignore ibm, platform-facilities updates

On VMs with NX encryption, compression, and/or RNG offload, these
capabilities are described by nodes in the ibm,platform-facilities device
tree hierarchy:

$ tree -d /sys/firmware/devicetree/base/ibm,platform-facilities/
/sys/firmware/devicetree/base/ibm,platform-facilities/
├── ibm,compression-v1
├── ibm,random-v1
└── ibm,sym-encryption-v1

3 directories

The acceleration functions that these nodes describe are not disrupted by
live migration, not even temporarily.

But the post-migration ibm,update-nodes sequence firmware always sends
"delete" messages for this hierarchy, followed by an "add" directive to
reconstruct it via ibm,configure-connector (log with debugging statements
enabled in mobility.c):

mobility: removing node /ibm,platform-facilities/ibm,random-v1:4294967285
mobility: removing node /ibm,platform-facilities/ibm,compression-v1:4294967284
mobility: removing node /ibm,platform-facilities/ibm,sym-encryption-v1:4294967283
mobility: removing node /ibm,platform-facilities:4294967286
...
mobility: added node /ibm,platform-facilities:4294967286

Note we receive a single "add" message for the entire hierarchy, and what
we receive from the ibm,configure-connector sequence is the top-level
platform-facilities node along with its three children. The debug message
simply reports the parent node and not the whole subtree.

Also, significantly, the nodes added are almost completely equivalent to
the ones removed; even phandles are unchanged. ibm,shared-interrupt-pool in
the leaf nodes is the only property I've observed to differ, and Linux does
not use that. So in practice, the sum of update messages Linux receives for
this hierarchy is equivalent to minor property updates.

We succeed in removing the original hierarchy from the device tree. But the
vio bus code is ignorant of this, and does not unbind or relinquish its
references. The leaf nodes, still reachable through sysfs, of course still
refer to the now-freed ibm,platform-facilities parent node, which makes
use-after-free possible:

refcount_t: addition on 0; use-after-free.
WARNING: CPU: 3 PID: 1706 at lib/refcount.c:25 refcount_warn_saturate+0x164/0x1f0
refcount_warn_saturate+0x160/0x1f0 (unreliable)
kobject_get+0xf0/0x100
of_node_get+0x30/0x50
of_get_parent+0x50/0xb0
of_fwnode_get_parent+0x54/0x90
fwnode_count_parents+0x50/0x150
fwnode_full_name_string+0x30/0x110
device_node_string+0x49c/0x790
vsnprintf+0x1c0/0x4c0
sprintf+0x44/0x60
devspec_show+0x34/0x50
dev_attr_show+0x40/0xa0
sysfs_kf_seq_show+0xbc/0x200
kernfs_seq_show+0x44/0x60
seq_read_iter+0x2a4/0x740
kernfs_fop_read_iter+0x254/0x2e0
new_sync_read+0x120/0x190
vfs_read+0x1d0/0x240

Moreover, the "new" replacement subtree is not correctly added to the
device tree, resulting in ibm,platform-facilities parent node without the
appropriate leaf nodes, and broken symlinks in the sysfs device hierarchy:

$ tree -d /sys/firmware/devicetree/base/ibm,platform-facilities/
/sys/firmware/devicetree/base/ibm,platform-facilities/

0 directories

$ cd /sys/devices/vio ; find . -xtype l -exec file {} +
./ibm,sym-encryption-v1/of_node: broken symbolic link to
../../../firmware/devicetree/base/ibm,platform-facilities/ibm,sym-encryption-v1
./ibm,random-v1/of_node: broken symbolic link to
../../../firmware/devicetree/base/ibm,platform-facilities/ibm,random-v1
./ibm,compression-v1/of_node: broken symbolic link to
../../../firmware/devicetree/base/ibm,platform-facilities/ibm,compression-v1

This is because add_dt_node() -> dlpar_attach_node() attaches only the
parent node returned from configure-connector, ignoring any children. This
should be corrected for the general case, but fixing that won't help with
the stale OF node references, which is the more urgent problem.

One way to address that would be to make the drivers respond to node
removal notifications, so that node references can be dropped
appropriately. But this would likely force the drivers to disrupt active
clients for no useful purpose: equivalent nodes are immediately re-added.
And recall that the acceleration capabilities described by the nodes remain
available throughout the whole process.

The solution I believe to be robust for this situation is to convert
remove+add of a node with an unchanged phandle to an update of the node's
properties in the Linux device tree structure. That would involve changing
and adding a fair amount of code, and may take several iterations to land.

Until that can be realized we have a confirmed use-after-free and the
possibility of memory corruption. So add a limited workaround that
discriminates on the node type, ignoring adds and removes. This should be
amenable to backporting in the meantime.

Fixes: 410bccf97881 ("powerpc/pseries: Partition migration in the kernel")
Cc: stable@vger.kernel.org
Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211020194703.2613093-1-nathanl@linux.ibm.com

powerpc/pseries/mobility: handle premature return from H_JOIN

The pseries join/suspend sequence in its current form was written with
the assumption that it was the only user of H_PROD and that it needn't
handle spurious successful returns from H_JOIN. That's wrong;
powerpc's paravirt spinlock code uses H_PROD, and CPUs entering
do_join() can be woken prematurely from H_JOIN with a status of
H_SUCCESS as a result. This causes all CPUs to exit the sequence
early, preventing suspend from occurring at all.

Add a 'done' boolean flag to the pseries_suspend_info struct, and have
the waking thread set it before waking the other threads. Threads
which receive H_SUCCESS from H_JOIN retry if the 'done' flag is still
unset.

Fixes: 9327dc0aeef3 ("powerpc/pseries/mobility: use stop_machine for join/suspend")
Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210315080045.460331-3-nathanl@linux.ibm.com

powerpc/pseries/mobility: use struct for shared state

The atomic_t counter is the only shared state for the join/suspend
sequence so far, but that will change. Contain it in a
struct (pseries_suspend_info), and document its intended use. No
functional change.

Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210315080045.460331-2-nathanl@linux.ibm.com

powerpc/pseries/mobility: refactor node lookup during DT update

In pseries_devicetree_update(), with each call to ibm,update-nodes the
partition firmware communicates the node to be deleted or updated by
placing its phandle in the work buffer. Each of delete_dt_node(),
update_dt_node(), and add_dt_node() have duplicate lookups using the
phandle value and corresponding refcount management.

Move the lookup and of_node_put() into pseries_devicetree_update(),
and emit a warning on any failed lookups.

Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201207215200.1785968-29-nathanl@linux.ibm.com

powerpc/rtas: dispatch partition migration requests to pseries

sys_rtas() cannot call ibm,suspend-me directly in the same way it
handles other inputs. Instead it must dispatch the request to code
that can first perform the H_JOIN sequence before any call to
ibm,suspend-me can succeed. Over time kernel/rtas.c has accreted a fair
amount of platform-specific code to implement this.

Since a different, more robust implementation of the suspend sequence
is now in the pseries platform code, we want to dispatch the request
there.

Note that invoking ibm,suspend-me via the RTAS syscall is all but
deprecated; this change preserves ABI compatibility for old programs
while providing to them the benefit of the new partition suspend
implementation. This is a behavior change in that the kernel performs
the device tree update and firmware activation before returning, but
experimentation indicates this is tolerated fine by legacy user space.

Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201207215200.1785968-16-nathanl@linux.ibm.com

powerpc/pseries/mobility: retry partition suspend after error

This is a mitigation for the relatively rare occurrence where a
virtual IOA can be in a transient state that prevents the
suspend/migration from succeeding, resulting in an error from
ibm,suspend-me.

If the join/suspend sequence returns an error, it is acceptable to
retry as long as the VASI suspend session state is still
"Suspending" (i.e. the platform is still waiting for the OS to
suspend).

Retry a few times on suspend failure while this condition holds,
progressively increasing the delay between attempts. We don't want to
retry indefinitey because firmware emits an error log event on each
unsuccessful attempt.

Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201207215200.1785968-15-nathanl@linux.ibm.com

powerpc/pseries/mobility: signal suspend cancellation to platform

If we're returning an error to user space, use H_VASI_SIGNAL to send a
cancellation request to the platform. This isn't strictly required but
it communicates that Linux will not attempt to complete the suspend,
which allows the various entities involved to promptly end the
operation in progress.

Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201207215200.1785968-14-nathanl@linux.ibm.com

powerpc/pseries/mobility: use stop_machine for join/suspend

The partition suspend sequence as specified in the platform
architecture requires that all active processor threads call
H_JOIN, which:

- suspends the calling thread until it is the target of
an H_PROD; or
- immediately returns H_CONTINUE, if the calling thread is the last to
call H_JOIN. This thread is expected to call ibm,suspend-me to
completely suspend the partition.

Upon returning from ibm,suspend-me the calling thread must wake all
others using H_PROD.

rtas_ibm_suspend_me_unsafe() uses on_each_cpu() to implement this
protocol, but because of its synchronizing nature this is susceptible
to deadlock versus users of stop_machine() or other callers of
on_each_cpu().

Not only is stop_machine() intended for use cases like this, it
handles error propagation and allows us to keep the data shared
between CPUs minimal: a single atomic counter which ensures exactly
one CPU will wake the others from their joined states.

Switch the migration code to use stop_machine() and a less complex
local implementation of the H_JOIN/ibm,suspend-me logic, which
carries additional benefits:

- more informative error reporting, appropriately ratelimited
- resets the lockup detector / watchdog on resume to prevent lockup
warnings when the OS has been suspended for a time exceeding the
threshold.

Fixes: 91dc182ca6e2 ("[PATCH] powerpc: special-case ibm,suspend-me RTAS call")
Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201207215200.1785968-13-nathanl@linux.ibm.com

powerpc/pseries/mobility: extract VASI session polling logic

The behavior of rtas_ibm_suspend_me_unsafe() is to return -EAGAIN to
the caller until the specified VASI suspend session state makes the
transition from H_VASI_ENABLED to H_VASI_SUSPENDING. In the interest
of separating concerns to prepare for a new implementation of the
join/suspend sequence, extract VASI session polling logic into a
couple of local functions. Waiting for the session state to reach
H_VASI_SUSPENDING before calling rtas_ibm_suspend_me_unsafe() ensures
that we will never get an EAGAIN result necessitating a retry. No
user-visible change in behavior is intended.

Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201207215200.1785968-12-nathanl@linux.ibm.com

powerpc/pseries/mobility: use rtas_activate_firmware() on resume

It's incorrect to abort post-suspend processing if
ibm,activate-firmware isn't available. Use rtas_activate_firmware(),
which logs this condition appropriately and allows us to proceed.

Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201207215200.1785968-11-nathanl@linux.ibm.com

powerpc/pseries/mobility: error message improvements

- Convert printk(KERN_ERR) to pr_err().
- Include errno in property update failure message.
- Remove reference to "Post-mobility" from device tree update message:
with pr_err() it will have a "mobility:" prefix.

Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201207215200.1785968-10-nathanl@linux.ibm.com

powerpc/pseries/mobility: add missing break to default case

update_dt_node() has a switch statement where the default case lacks a
break statement.

Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201207215200.1785968-9-nathanl@linux.ibm.com

powerpc/pseries/mobility: don't error on absence of ibm, update-nodes

Treat the absence of the ibm,update-nodes function as benign instead
of reporting an error. If the platform does not provide that facility,
it's not a problem for Linux.

Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201207215200.1785968-8-nathanl@linux.ibm.com

powerpc/rtas: rtas_ibm_suspend_me -> rtas_ibm_suspend_me_unsafe

The pseries partition suspend sequence requires that all active CPUs
call H_JOIN, which suspends all but one of them with interrupts
disabled. The "chosen" CPU is then to call ibm,suspend-me to complete
the suspend. Upon returning from ibm,suspend-me, the chosen CPU is to
use H_PROD to wake the joined CPUs.

Using on_each_cpu() for this, as rtas_ibm_suspend_me() does to
implement partition migration, is susceptible to deadlock with other
users of on_each_cpu() and with users of stop_machine APIs. The
callback passed to on_each_cpu() is not allowed to synchronize with
other CPUs in the way it is used here.

Complicating the fix is the fact that rtas_ibm_suspend_me() also
occupies the function name that should be used to provide a more
conventional wrapper for ibm,suspend-me. Rename rtas_ibm_suspend_me()
to rtas_ibm_suspend_me_unsafe() to free up the name and indicate that
it should not gain users.

Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201207215200.1785968-4-nathanl@linux.ibm.com

powerpc/64s: rename pnv|pseries_setup_rfi_flush to _setup_security_mitigations

pseries|pnv_setup_rfi_flush already does the count cache flush setup, and
we just added entry and uaccess flushes. So the name is not very accurate
any more. In both platforms we then also immediately setup the STF flush.

Rename them to _setup_security_mitigations and fold the STF flush in.

Signed-off-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

powerpc/pseries/mobility: Add pr_debug() for device tree changes

When investigating issues with partition migration or resource
reassignments it is helpful to have a log of which nodes and
properties in the device tree have changed. Use pr_debug() so it's
easy to enable these at runtime with the dynamic debug facility.

Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190627053044.9238-3-nathanl@linux.ibm.com

powerpc/pseries/mobility: Set pr_fmt()

The pr_err() callsites in mobility.c already manually include a
"mobility:" prefix, let's make it official for the benefit of messages
to be added later.

Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190627053044.9238-2-nathanl@linux.ibm.com

powerpc/pseries: remove prrn special case from DT update path

pseries_devicetree_update() is no longer called with PRRN_SCOPE. The
purpose of prrn_update_node() was to remove and then add back a LMB
whose NUMA assignment had changed. This has never been reliable, and
this codepath has been default-disabled for several releases. Remove
prrn_update_node().

Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200612051238.1007764-16-nathanl@linux.ibm.com

powerpc/numa: remove start/stop_topology_update()

These APIs have become no-ops, so remove them and all call sites.

Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Reviewed-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200612051238.1007764-12-nathanl@linux.ibm.com

powerpc/pseries: Update hv-24x7 information after migration

Function 'read_sys_info_pseries()' is added to get system parameter
values like number of sockets and chips per socket.
and it gets these details via rtas_call with token
"PROCESSOR_MODULE_INFO".

Incase lpar migrate from one system to another, system
parameter details like chips per sockets or number of sockets might
change. So, it needs to be re-initialized otherwise, these values
corresponds to previous system values.
This patch adds a call to 'read_sys_info_pseries()' from
'post-mobility_fixup()' to re-init the physsockets and physchips values

Signed-off-by: Kajol Jain <kjain@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200525104308.9814-6-kjain@linux.ibm.com

powerpc/pseries/mobility: use cond_resched when updating device tree

After a partition migration, pseries_devicetree_update() processes
changes to the device tree communicated from the platform to
Linux. This is a relatively heavyweight operation, with multiple
device tree searches, memory allocations, and conversations with
partition firmware.

There's a few levels of nested loops which are bounded only by
decisions made by the platform, outside of Linux's control, and indeed
we have seen RCU stalls on large systems while executing this call
graph. Use cond_resched() in these loops so that the cpu is yielded
when needed.

Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190802192926.19277-4-nathanl@linux.ibm.com

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500

Based on 2 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation #

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 4122 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

powerpc/pseries/mobility: rebuild cacheinfo hierarchy post-migration

It's common for the platform to replace the cache device nodes after a
migration. Since the cacheinfo code is never informed about this, it
never drops its references to the source system's cache nodes, causing
it to wind up in an inconsistent state resulting in warnings and oopses
as soon as CPU online/offline occurs after the migration, e.g.

cache for /cpus/l3-cache@3113(Unified) refers to cache for /cpus/l2-cache@200d(Unified)
WARNING: CPU: 15 PID: 86 at arch/powerpc/kernel/cacheinfo.c:176 release_cache+0x1bc/0x1d0
[...]
NIP release_cache+0x1bc/0x1d0
LR release_cache+0x1b8/0x1d0
Call Trace:
release_cache+0x1b8/0x1d0 (unreliable)
cacheinfo_cpu_offline+0x1c4/0x2c0
unregister_cpu_online+0x1b8/0x260
cpuhp_invoke_callback+0x114/0xf40
cpuhp_thread_fun+0x270/0x310
smpboot_thread_fn+0x2c8/0x390
kthread+0x1b8/0x1c0
ret_from_kernel_thread+0x5c/0x68

Using device tree notifiers won't work since we want to rebuild the
hierarchy only after all the removals and additions have occurred and
the device tree is in a consistent state. Call cacheinfo_teardown()
before processing device tree updates, and rebuild the hierarchy
afterward.

Fixes: 410bccf97881 ("powerpc/pseries: Partition migration in the kernel")
Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

powerpc/pseries/mobility: prevent cpu hotplug during DT update

CPU online/offline code paths are sensitive to parts of the device
tree (various cpu node properties, cache nodes) that can be changed as
a result of a migration.

Prevent CPU hotplug while the device tree potentially is inconsistent.

Fixes: 410bccf97881 ("powerpc/pseries: Partition migration in the kernel")
Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

powerpc/pseries/mobility: Extend start/stop topology update scope

The powerpc mobility code may receive RTAS requests to perform PRRN
(Platform Resource Reassignment Notification) topology changes at any
time, including during LPAR migration operations.

In some configurations where the affinity of CPUs or memory is being
changed on that platform, the PRRN requests may apply or refer to
outdated information prior to the complete update of the device-tree.

This patch changes the duration for which topology updates are
suppressed during LPAR migrations from just the rtas_ibm_suspend_me()
/ 'ibm,suspend-me' call(s) to cover the entire migration_store()
operation to allow all changes to the device-tree to be applied prior
to accepting and applying any PRRN requests.

For tracking purposes, pr_info notices are added to the functions
start_topology_update() and stop_topology_update() of 'numa.c'.

Signed-off-by: Michael Bringmann <mwb@linux.vnet.ibm.com>
Reviewed-by: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

powerpc/pseries: Remove unneeded uses of dlpar work queue

There are three instances in which dlpar hotplug events are invoked;
handling a hotplug interrupt (in a kvm guest), handling a dlpar
request through sysfs, and updating LMB affinity when handling a
PRRN event. Only in the case of handling a hotplug interrupt do we
have to put the work on a workqueue, the other cases can handle the
dlpar request directly.

This patch exports the handle_dlpar_errorlog() function so that
dlpar hotplug events can be handled directly and updates the two
instances mentioned above to use the direct invocation.

Signed-off-by: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

powerpc: clean the inclusion of stringify.h

Only include linux/stringify.h is files using __stringify()

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

powerpc/rfi-flush: Call setup_rfi_flush() after LPM migration

We might have migrated to a machine that uses a different flush type,
or doesn't need flushing at all.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Mauricio Faria de Oliveira <mauricfo@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

powerpc: Use octal numbers for file permissions

Symbolic macros are unintuitive and hard to read, whereas octal constants
are much easier to interpret. Replace macros for the basic permission
flags (user/group/other read/write/execute) with numeric constants
instead, across the whole powerpc tree.

Introducing a significant number of changes across the tree for no runtime
benefit isn't exactly desirable, but so long as these macros are still
used in the tree people will keep sending patches that add them. Not only
are they hard to parse at a glance, there are multiple ways of coming to
the same value (as you can see with 0444 and 0644 in this patch) which
hurts readability.

Signed-off-by: Russell Currey <ruscur@russell.cc>
Reviewed-by: Cyril Bur <cyrilbur@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

powerpc/pseries: Fix parent_dn reference leak in add_dt_node()

A reference to the parent device node is held by add_dt_node() for the
node to be added. If the call to dlpar_configure_connector() fails
add_dt_node() returns ENOENT and that reference is not freed.

Add a call to of_node_put(parent_dn) prior to bailing out after a
failed dlpar_configure_connector() call.

Fixes: 8d5ff320766f ("powerpc/pseries: Make dlpar_configure_connector parent node aware")
Cc: stable@vger.kernel.org # v3.12+
Signed-off-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

powerpc: pseries: remove dlpar_attach_node dependency on full path

In preparation to stop storing the full node path in full_name, remove the
dependency on full_name from dlpar_attach_node(). Callers of
dlpar_attach_node() already have the parent device_node, so just pass the
parent node into dlpar_attach_node instead of the path. This avoids doing
a lookup of the parent node by the path.

Signed-off-by: Rob Herring <robh@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

driver core: remove CLASS_ATTR usage

There was only 2 remaining users of CLASS_ATTR() so let's finally get
rid of them and force everyone to use the correct RW/RO/WO versions
instead.

Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

powerpc/pseries: Update affinity for memory and cpus specified in a PRRN event

Extend the existing PRRN infrastructure to perform the actual affinity
updating for cpus and memory in addition to the device tree updating.
For cpus, dynamic affinity updating already appears to exist in the
kernel in the form of arch_update_cpu_topology(). For memory, we must
place a READD operation on the hotplug queue for any phandle included in
the PRRN event that is determined to be an LMB.

Signed-off-by: John Allen <jallen@linux.vnet.ibm.com>
Reviewed-by: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

powerpc: Update of_remove_property() call sites to remove null checking

After obtaining a property from of_find_property() and before calling
of_remove_property() most code checks to ensure that the property
returned from of_find_property() is not null. The previous patch moved
this check to the start of the function of_remove_property() in order to
avoid the case where this check isn't done and a null value is passed.
This ensures the check is always conducted before taking locks and
attempting to remove the property. Thus it is no longer necessary to
perform a check for null values before invoking of_remove_property().

Update of_remove_property() call sites in order to remove redundant
checking for null property value as check is now performed within the
of_remove_property function().

Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
[mpe: Unbreak some lines which are just >80 chars for readability]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

powerpc/pseries: Simplify check for suspendability during suspend/migration

During suspend/migration operation we must wait for the VASI state reported
by the hypervisor to become Suspending prior to making the ibm,suspend-me
RTAS call. Calling routines to rtas_ibm_supend_me() pass a vasi_state variable
that exposes the VASI state to the caller. This is unnecessary as the caller
only really cares about the following three conditions; if there is an error
we should bailout, success indicating we have suspended and woken back up so
proceed to device tree update, or we are not suspendable yet so try calling
rtas_ibm_suspend_me again shortly.

This patch removes the extraneous vasi_state variable and simply uses the
return code to communicate how to proceed. We either succeed, fail, or get
-EAGAIN in which case we sleep for a second before trying to call
rtas_ibm_suspend_me again. The behaviour of ppc_rtas() remains the same,
but migrate_store() now returns the propogated error code on failure.
Previously -1 was returned from migrate_store() in the failure case which
equates to -EPERM and was clearly wrong.

Signed-off-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.com>
Cc: Nathan Fontenont <nfont@linux.vnet.ibm.com>
Cc: Cyril Bur <cyrilbur@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

powerpc/pseries: Introduce api_version to migration sysfs interface

The /sys/kernel/mobility/migration interface was added all the way back
in 2.6.37. However, the drmgr userspace tool was never augmented to use
this interface to perfrom migrations. Instead it has continued using a
faux rtas call coupled with performing the device tree update processing
in userspace and communicating it back to the kernel via the ugly
/proc/ppc64/ofdt interface.

Up until 3.12 the device tree update code in the kernel was badly broken
and bit rotting. This code was fixed in 3.12 and is now utilized by the
kernel suspend code as of 3.15. The kernel is now better suited to
handle the post-mobility fixup of the device tree and drmgr should be
transitioned to using the sysfs migration interface.

This patch introduces the api_version sysfs file to /sys/kernel/mobility
as a means for drmgr to query the current implementation level of the
kernel migration code. This initial versioning indicates it is capable
of perfroming all current PAPR requirements for migration including the
post-mobility firmware activation and device tree update.

Signed-off-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.com>
Cc: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Cc: Cyril Bur <cyrilbur@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

powerpc/pseries: Little endian fixes for post mobility device tree update

We currently use the device tree update code in the kernel after resuming
from a suspend operation to re-sync the kernels view of the device tree with
that of the hypervisor. The code as it stands is not endian safe as it relies
on parsing buffers returned by RTAS calls that thusly contains data in big
endian format.

This patch annotates variables and structure members with __be types as well
as performing necessary byte swaps to cpu endian for data that needs to be
parsed.

Signed-off-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.com>
Cc: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Cc: Cyril Bur <cyrilbur@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

powerpc/pseries: Fix endian problems with LE migration

RTAS events require arguments be passed in big endian while hypercalls
have their arguments passed in registers and the values should therefore
be in CPU endian.

The "ibm,suspend_me" 'RTAS' call makes a sequence of hypercalls to setup
one true RTAS call. This means that "ibm,suspend_me" is handled
specially in the ppc_rtas() syscall.

The ppc_rtas() syscall has its arguments in big endian and can therefore
pass these arguments directly to the RTAS call. "ibm,suspend_me" is
handled specially from within ppc_rtas() (by calling rtas_ibm_suspend_me())
which has left an endian bug on little endian systems due to the
requirement of hypercalls. The return value from rtas_ibm_suspend_me()
gets returned in cpu endian, and is left unconverted, also a bug on
little endian systems.

rtas_ibm_suspend_me() does not actually make use of the rtas_args that
it is passed. This patch removes the convoluted use of the rtas_args
struct to pass params to rtas_ibm_suspend_me() in favour of passing what
it needs as actual arguments. This patch also ensures the two callers of
rtas_ibm_suspend_me() pass function parameters in cpu endian and in the
case of ppc_rtas(), converts the return value.

migrate_store() (the other caller of rtas_ibm_suspend_me()) is from a
sysfs file which deals with everything in cpu endian so this function
only underwent cleanup.

This patch has been tested with KVM both LE and BE and on PowerVM both
LE and BE. Under QEMU/KVM the migration happens without touching these
code pathes.

For PowerVM there is no obvious regression on BE and the LE code path
now provides the correct parameters to the hypervisor.

Signed-off-by: Cyril Bur <cyrilbur@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc: replace obsolete strict_strto* calls

Replace strict_strto calls with more appropriate kstrto calls

Signed-off-by: Daniel Walter <dwalter@google.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

powerpc/pseries: Switch pseries drivers to use machine_xxx_initcall()

A lot of the code in platforms/pseries is using non-machine initcalls.
That means if a kernel built with pseries support runs on another
platform, for example powernv, the initcalls will still run.

Most of these cases are OK, though sometimes only due to luck. Some were
having more effect:

* hcall_inst_init
- Checking FW_FEATURE_LPAR which is set on ps3 & celleb.
* mobility_sysfs_init
- created sysfs files unconditionally
- but no effect due to ENOSYS from rtas_ibm_suspend_me()
* apo_pm_init
- created sysfs, allows write
- nothing checks the value written to though
* alloc_dispatch_log_kmem_cache
- creating kmem_cache on non-pseries machines

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

powerpc/pseries: Device tree should only be updated once after suspend/migrate

The current code makes rtas calls for update-nodes, activate-firmware and then
update-nodes again. The FW provides the same data for both update-nodes calls.
As a result a proc entry exists error is reported for the second update while
adding device nodes.

This patch makes a single rtas call for update-nodes after activating the FW.
It also add rtas_busy delay for the activate-firmware rtas call.

Signed-off-by: Haren Myneni <hbabu@us.ibm.com>
Signed-off-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

powerpc/pseries: Add mising of_node_put in delete_dt_node

The node to be detached is retrieved via its phandle by a call to
of_find_node_by_phandle which increments the ref count. We need a matching
call to of_node_put to decrement the ref count and ensure the node is
actually freed.

Signed-off-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.com>
Acked-by: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

powerpc/pseries: Make dlpar_configure_connector parent node aware

Currently the device nodes created in the device subtree returned by a call to
dlpar_configure_connector are all named in the root node. This is because the
the node name in the work area returned by ibm,configure-connector rtas call
only contains the node name and not the entire node path. Passing the parent
node where the new subtree will be created to dlpar_configure_connector allows
the correct node path to be prefixed in the full_name field.

Signed-off-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.com>
Acked-by: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

powerpc/pseries: Fix parsing of initial node path in update_dt_node

On the first call to ibm,update-properties for a node the first property
returned is the full node path. Currently this is not parsed correctly by the
update_dt_node function. Commit 2e9b7b0 attempted to fix this, but was
incorrect as it made a wrong assumption about the layout of the first
property in the work area. Further, if ibm,update-properties must be called
multiple times for the same node this special property should only be skipped
after the initial call. The first property descriptor returned consists of
the property name, property value length, and property value. The property
name is an empty string, property length is encoded in 4 byte integer, and
the property value is the node path.

Signed-off-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.com>
Acked-by: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

powerpc/pseries: Pack update_props_workarea to map correctly to rtas buffer header

The work area buffer returned by the ibm,update-properties rtas call contains
20 bytes of header information prior to the property value descriptor data.
Currently update_dt_node tries to advance over this header using sizeof(upwa).
The update_props_workarea struct contains 20 bytes worth of fields, that map
to the relevant header data, but the sizeof the structure is 24 bytes due to
4 bytes of padding at the end of the structure. Packing the structure ensures
that we don't advance too far over the rtas buffer.

Signed-off-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.com>
Acked-by: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

powerpc/pseries: Fix over writing of rtas return code in update_dt_node

The rc variable is initially used to store the return code from the
ibm,update-properties rtas call which returns 0 or 1 on success. A return
code of 1 indicates that ibm,update-properties must be called again for the
node. However, the rc variable is overwritten by a call to update_dt_prop
which returns 0 on success. This results in ibm,update-properties not being
called again for the given node when the rtas call rc was previously 1.

Signed-off-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.com>
Acked-by: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

powerpc/pseries: Fix creation of loop in device node property list

The update_dt_prop helper function fails to set the IN/OUT parameter prop to
NULL after a complete property has been parsed from the work area returned by
the ibm,update-properties rtas function. This results in the property list of
the device node being updated is corrupted and becomes a loop since the same
property structure is used repeatedly.

Signed-off-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.com>
Acked-by: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

powerpc/pseries: Correct buffer parsing in update_dt_node()

Correct parsing of the buffer returned from ibm,update-properties. The first
element is a length and the path to the property which is slightly different
from the list of properties in the buffer so we need to specifically
handle this.

Signed-off-by: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

powerpc/pseries: Expose pseries devicetree_update()

Newer firmware on Power systems can transparently reassign platform resources
(CPU and Memory) in use. For instance, if a processor or memory unit is
predicted to fail, the platform may transparently move the processing to an
equivalent unused processor or the memory state to an equivalent unused
memory unit. However, reassigning resources across NUMA boundaries may alter
the performance of the partition. When such reassignment is necessary, the
Platform Resource Reassignment Notification (PRRN) option provides a
mechanism to inform the Linux kernel of changes to the NUMA affinity of
its platform resources.

When rtasd receives a PRRN event, it needs to make a series of RTAS
calls (ibm,update-nodes and ibm,update-properties) to retrieve the
updated device tree information. These calls are already handled in the
pseries_devicetree_update() routine used in partition migration.

This patch exposes pseries_devicetree_update() to make it accessible
to other pseries routines, this patch also updates pseries_devicetree_update()
to take a 32-bit scope parameter. The scope value, which was previously hard
coded to 1 for partition migration, is used for the RTAS calls
ibm,update-nodes/properties to update the device tree.

Signed-off-by: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

powerpc+of: Rename the drivers/of prom_* functions to of_*

Rename the prom_*_property routines of the generic OF code to of_*_property.
This brings them in line with the naming used by the rest of the OF code.

Signed-off-by: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Acked-by: Geoff Levand <geoff@infradead.org>
Acked-by: Rob Herring <rob.herring@calxeda.com>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

of: Improve prom_update_property() function

prom_update_property() currently fails if the property doesn't
actually exist yet which isn't what we want. Change to add-or-update
instead of update-only, then we can remove a lot duplicated lines.

Suggested-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Dong Aisheng <dong.aisheng@linaro.org>
Acked-by: Rob Herring <rob.herring@calxeda.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

powerpc: Fix up implicit stat.h users

They get it via module.h (via device.h) but we want to clean that up.
When we do, we'll get things like:

ibmebus.c:314: error: 'S_IWUSR' undeclared here (not in a function)
vio.c:972: error: 'S_IWUSR' undeclared here (not in a function)

so add in the stat header it is using explicitly in advance.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

powerpc/pseries: Partition migration in the kernel

Enable partition migration in the kernel. To do this a new sysfs file,
/sys/kernel/mobility/migration, is created. In order to initiate a migration
the stream id (generated by the HMC managing the system) is written to this
file.

After a migration occurs, and what is the majority of this code, the device
tree needs to be updated for the new system the partition is running on. This
is done via the ibm,update-nodes and ibm,update-properties rtas calls which
return information regarding which nodes and properties of the device tree
are to be added/removed/updated.

Signed-off-by: Nathan Fontenot <nfont@austin.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>