There is only a single user remaining.  We can simply lookup the nid only
used for node offlining purposes when walking our memory blocks.  We don't
expect to remove multi-nid ranges; and if we'd ever do, we most probably
don't care about removing multi-nid ranges that actually result in empty
nodes.

If ever required, we can detect the "multi-nid" scenario and simply try
offlining all online nodes.

Link: https://lkml.kernel.org/r/20210712124052.26491-4-david@redhat.comSigned-off-by: NDavid Hildenbrand <david@redhat.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Len Brown <lenb@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Nathan Lynch <nathanl@linux.ibm.com>
Cc: Laurent Dufour <ldufour@linux.ibm.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Cc: Scott Cheloha <cheloha@linux.ibm.com>
Cc: Anton Blanchard <anton@ozlabs.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jia He <justin.he@arm.com>
Cc: Joe Perches <joe@perches.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michel Lespinasse <michel@lespinasse.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Pankaj Gupta <pankaj.gupta@ionos.com>
Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Pierre Morel <pmorel@linux.ibm.com>
Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Cc: Rich Felker <dalias@libc.org>
Cc: Sergei Trofimovich <slyfox@gentoo.org>
Cc: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Yang <richard.weiyang@linux.alibaba.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

After LPM, when migrating from a system with security mitigation enabled
to a system with mitigation disabled, the security flavor exposed in
/proc is not correctly set back to 0.

Do not assume the value of the security flavor is set to 0 when entering
init_cpu_char_feature_flags(), so when called after a LPM, the value is
set correctly even if the mitigation are not turned off.

Fixes: 6ce56e1a ("powerpc/pseries: export LPAR security flavor in lparcfg")
Cc: stable@vger.kernel.org # v5.13+
Signed-off-by: NLaurent Dufour <ldufour@linux.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210805152308.33988-1-ldufour@linux.ibm.com

With commit c9f34013 ("powerpc: Always enable queued spinlocks for
64s, disable for others") CONFIG_PPC_QUEUED_SPINLOCKS is always
enabled on ppc64le, external modules that use spinlock APIs are
failing.

  ERROR: modpost: GPL-incompatible module XXX.ko uses GPL-only symbol 'shared_processor'

Before the above commit, modules were able to build without any
issues. Also this problem is not seen on other architectures. This
problem can be workaround if CONFIG_UNINLINE_SPIN_UNLOCK is enabled in
the config. However CONFIG_UNINLINE_SPIN_UNLOCK is not enabled by
default and only enabled in certain conditions like
CONFIG_DEBUG_SPINLOCKS is set in the kernel config.

  #include <linux/module.h>
  spinlock_t spLock;

  static int __init spinlock_test_init(void)
  {
          spin_lock_init(&spLock);
          spin_lock(&spLock);
          spin_unlock(&spLock);
          return 0;
  }

  static void __exit spinlock_test_exit(void)
  {
  	printk("spinlock_test unloaded\n");
  }
  module_init(spinlock_test_init);
  module_exit(spinlock_test_exit);

  MODULE_DESCRIPTION ("spinlock_test");
  MODULE_LICENSE ("non-GPL");
  MODULE_AUTHOR ("Srikar Dronamraju");

Given that spin locks are one of the basic facilities for module code,
this effectively makes it impossible to build/load almost any non GPL
modules on ppc64le.

This was first reported at https://github.com/openzfs/zfs/issues/11172

Currently shared_processor is exported as GPL only symbol.
Fix this for parity with other architectures by exposing
shared_processor to non-GPL modules too.

Fixes: 14c73bd3 ("powerpc/vcpu: Assume dedicated processors as non-preempt")
Cc: stable@vger.kernel.org # v5.5+
Reported-by: marc.c.dionne@gmail.com
Signed-off-by: NSrikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210729060449.292780-1-srikar@linux.vnet.ibm.com

Powerpc currently resets a CPU's idle task preempt_count to 0 before
said task starts executing the secondary startup routine (and becomes an
idle task proper).

This conflicts with commit f1a0a376 ("sched/core: Initialize the
idle task with preemption disabled").

which initializes all of the idle tasks' preempt_count to
PREEMPT_DISABLED during smp_init(). Note that this was superfluous
before said commit, as back then the hotplug machinery would invoke
init_idle() via idle_thread_get(), which would have already reset the
CPU's idle task's preempt_count to PREEMPT_ENABLED.

Get rid of this preempt_count write.

Fixes: f1a0a376 ("sched/core: Initialize the idle task with preemption disabled")
Reported-by: NBharata B Rao <bharata@linux.ibm.com>
Signed-off-by: NValentin Schneider <valentin.schneider@arm.com>
Tested-by: NGuenter Roeck <linux@roeck-us.net>
Tested-by: NBharata B Rao <bharata@linux.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210707183831.2106509-1-valentin.schneider@arm.com

There are patches in flight to break the dependency between asm/irq.h
and linux/irqdomain.h, which would break compilation of vas.c because it
needs the declaration of irq_create_mapping() etc.

So add an explicit include of irqdomain.h to avoid that becoming a
problem in future.
Reported-by: NStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210625045337.3197833-1-mpe@ellerman.id.au

Instead of making bare calls to get-sensor-state, use
rtas_get_sensor(), which correctly handles busy and extended delay
statuses.

Fixes: ab519a01 ("powerpc/pseries: Kernel DLPAR Infrastructure")
Signed-off-by: NNathan Lynch <nathanl@linux.ibm.com>
Reviewed-by: NLaurent Dufour <ldufour@linux.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210504025329.1713878-1-nathanl@linux.ibm.com

There is a spelling mistake "byes" -> "bytes" in a comment of
function drc_pmem_query_stats(). Fix that typo.
Signed-off-by: NKajol Jain <kjain@linux.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210418074003.6651-1-kjain@linux.ibm.com

Commit a21d1bec ("powerpc: Reintroduce is_kvm_guest() as a fast-path
check") added is_kvm_guest() and changed kvm_para_available() to use it.

is_kvm_guest() checks a static key, kvm_guest, and that static key is
set in check_kvm_guest().

The problem is check_kvm_guest() is only called on pseries, and even
then only in some configurations. That means is_kvm_guest() always
returns false on all non-pseries and some pseries depending on
configuration. That's a bug.

For PR KVM guests this is noticable because they no longer do live
patching of themselves, which can be detected by the omission of a
message in dmesg such as:

  KVM: Live patching for a fast VM worked

To fix it make check_kvm_guest() an initcall, to ensure it's always
called at boot. It needs to be core so that it runs before
kvm_guest_init() which is postcore. To be an initcall it needs to return
int, where 0 means success, so update that.

We still call it manually in pSeries_smp_probe(), because that runs
before init calls are run.

Fixes: a21d1bec ("powerpc: Reintroduce is_kvm_guest() as a fast-path check")
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210623130514.2543232-1-mpe@ellerman.id.au

Persistent memory devices like NVDIMMs can loose cached writes in case
something prevents flush on power-fail. Such situations are termed as
dirty shutdown and are exposed to applications as
last-shutdown-state (LSS) flag and a dirty-shutdown-counter(DSC) as
described at [1]. The latter being useful in conditions where multiple
applications want to detect a dirty shutdown event without racing with
one another.

PAPR-NVDIMMs have so far only exposed LSS style flags to indicate a
dirty-shutdown-state. This patch further adds support for DSC via the
"ibm,persistence-failed-count" device tree property of an NVDIMM. This
property is a monotonic increasing 64-bit counter thats an indication
of number of times an NVDIMM has encountered a dirty-shutdown event
causing persistence loss.

Since this value is not expected to change after system-boot hence
papr_scm reads & caches its value during NVDIMM probe and exposes it
as a PAPR sysfs attributed named 'dirty_shutdown' to match the name of
similarly named NFIT sysfs attribute. Also this value is available to
libnvdimm via PAPR_PDSM_HEALTH payload. 'struct nd_papr_pdsm_health'
has been extended to add a new member called 'dimm_dsc' presence of
which is indicated by the newly introduced PDSM_DIMM_DSC_VALID flag.

References:
[1] https://pmem.io/documents/Dirty_Shutdown_Handling-V1.0.pdfSigned-off-by: NVaibhav Jain <vaibhav@linux.ibm.com>
Reviewed-by: NAneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210624080621.252038-1-vaibhav@linux.ibm.com

In case performance stats for an nvdimm are not available, reading the
'perf_stats' sysfs file returns an -ENOENT error. A better approach is
to make the 'perf_stats' file entirely invisible to indicate that
performance stats for an nvdimm are unavailable.

So this patch updates 'papr_nd_attribute_group' to add a 'is_visible'
callback implemented as newly introduced 'papr_nd_attribute_visible()'
that returns an appropriate mode in case performance stats aren't
supported in a given nvdimm.

Also the initialization of 'papr_scm_priv.stat_buffer_len' is moved
from papr_scm_nvdimm_init() to papr_scm_probe() so that it value is
available when 'papr_nd_attribute_visible()' is called during nvdimm
initialization.

Even though 'perf_stats' attribute is available since v5.9, there are
no known user-space tools/scripts that are dependent on presence of its
sysfs file. Hence I dont expect any user-space breakage with this
patch.

Fixes: 2d02bf83 ("powerpc/papr_scm: Fetch nvdimm performance stats from PHYP")
Signed-off-by: NVaibhav Jain <vaibhav@linux.ibm.com>
Reviewed-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210513092349.285021-1-vaibhav@linux.ibm.com

Parse to and export from UUID own type, before dereferencing.
This also fixes wrong comment (Little Endian UUID is something else)
and should eliminate the direct strict types assignments.

Fixes: 43001c52 ("powerpc/papr_scm: Use ibm,unit-guid as the iset cookie")
Fixes: 259a948c ("powerpc/pseries/scm: Use a specific endian format for storing uuid from the device tree")
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: NAneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210616134303.58185-1-andriy.shevchenko@linux.intel.com

The validation done at the start of dlpar_memory_add_by_ic() is an all
of nothing scenario - if any LMBs in the range is marked as RESERVED we
can fail right away.

We then can remove the 'lmbs_available' var and its check with
'lmbs_to_add' since the whole LMB range was already validated in the
previous step.
Signed-off-by: NDaniel Henrique Barboza <danielhb413@gmail.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210622133923.295373-4-danielhb413@gmail.com

After a successful dlpar_add_lmb() call the LMB is marked as reserved.
Later on, depending whether we added enough LMBs or not, we rely on
the marked LMBs to see which ones might need to be removed, and we
remove the reservation of all of them.

These are done in for_each_drmem_lmb() loops without any break
condition. This means that we're going to check all LMBs of the partition
even after going through all the reserved ones.

This patch adds break conditions in both loops to avoid this. The
'lmbs_added' variable was renamed to 'lmbs_reserved', and it's now
being decremented each time a lmb reservation is removed, indicating
if there are still marked LMBs to be processed.
Signed-off-by: NDaniel Henrique Barboza <danielhb413@gmail.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210622133923.295373-3-danielhb413@gmail.com

The function is counting reserved LMBs as available to be added, but
they aren't. This will cause the function to miscalculate the available
LMBs and can trigger errors later on when executing dlpar_add_lmb().
Signed-off-by: NDaniel Henrique Barboza <danielhb413@gmail.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210622133923.295373-2-danielhb413@gmail.com

When an interrupt is taken, the SRR registers are set to return to where
it left off. Unless they are modified in the meantime, or the return
address or MSR are modified, there is no need to reload these registers
when returning from interrupt.

Introduce per-CPU flags that track the validity of SRR and HSRR
registers. These are cleared when returning from interrupt, when
using the registers for something else (e.g., OPAL calls), when
adjusting the return address or MSR of a context, and when context
switching (which changes the return address and MSR).

This improves the performance of interrupt returns.
Signed-off-by: NNicholas Piggin <npiggin@gmail.com>
[mpe: Fold in fixup patch from Nick]
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210617155116.2167984-5-npiggin@gmail.com

This allows the hypervisor / firmware to describe this workarounds to
the guest.
Signed-off-by: NNicholas Piggin <npiggin@gmail.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210503130243.891868-4-npiggin@gmail.com

This allows the hypervisor / firmware to describe these workarounds to
the guest.
Signed-off-by: NNicholas Piggin <npiggin@gmail.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210503130243.891868-2-npiggin@gmail.com

NX generates an interrupt when sees a fault on the user space
buffer and the hypervisor forwards that interrupt to OS. Then
the kernel handles the interrupt by issuing H_GET_NX_FAULT hcall
to retrieve the fault CRB information.

This patch also adds changes to setup and free IRQ per each
window and also handles the fault by updating the CSB.
Signed-off-by: NHaren Myneni <haren@linux.ibm.com>
Reviewed-by: NNicholas Piggin <npiggin@gmail.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/b8fc66dcb783d06a099a303e5cfc69087bb3357a.camel@linux.ibm.com

This patch adds VAS window allocatioa/close with the corresponding
hcalls. Also changes to integrate with the existing user space VAS
API and provide register/unregister functions to NX pseries driver.

The driver register function is used to create the user space
interface (/dev/crypto/nx-gzip) and unregister to remove this entry.

The user space process opens this device node and makes an ioctl
to allocate VAS window. The close interface is used to deallocate
window.
Signed-off-by: NHaren Myneni <haren@linux.ibm.com>
Reviewed-by: NNicholas Piggin <npiggin@gmail.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/e8d956bace3f182c4d2e66e343ff37cb0391d1fd.camel@linux.ibm.com

The hypervisor provides VAS capabilities for GZIP default and QoS
features. These capabilities gives information for the specific
features such as total number of credits available in LPAR,
maximum credits allowed per window, maximum credits allowed in
LPAR, whether usermode copy/paste is supported, and etc.

This patch adds the following:
- Retrieve all features that are provided by hypervisor using
  H_QUERY_VAS_CAPABILITIES hcall with 0 as feature type.
- Retrieve capabilities for the specific feature using the same
  hcall and the feature type (1 for QoS and 2 for default type).
Signed-off-by: NHaren Myneni <haren@linux.ibm.com>
Reviewed-by: NNicholas Piggin <npiggin@gmail.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/177c88608cb88f7b87d1c546103f18cec6c056b4.camel@linux.ibm.com

This patch adds the following hcall wrapper functions to allocate,
modify and deallocate VAS windows, and retrieve VAS capabilities.

H_ALLOCATE_VAS_WINDOW: Allocate VAS window
H_DEALLOCATE_VAS_WINDOW: Close VAS window
H_MODIFY_VAS_WINDOW: Setup window before using
H_QUERY_VAS_CAPABILITIES: Get VAS capabilities
Signed-off-by: NHaren Myneni <haren@linux.ibm.com>
Reviewed-by: NNicholas Piggin <npiggin@gmail.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/40fb02a4d56ca4e240b074a15029082055be5997.camel@linux.ibm.com

This patch adds hcalls and other definitions. Also define structs
that are used in VAS implementation on PowerVM.
Signed-off-by: NHaren Myneni <haren@linux.ibm.com>
Acked-by: NNicholas Piggin <npiggin@gmail.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/b4b8c594c27ee4aa6be9dc6dc4ee7331571cbbe8.camel@linux.ibm.com

A bunch of PPC files are missing the inclusion of linux/of.h and
linux/irqdomain.h, relying on transitive inclusion from another
file.

As we are about to break this dependency, make sure these dependencies
are explicit.
Signed-off-by: NMarc Zyngier <maz@kernel.org>

We don't need the 'lmbs_available' variable to count the valid LMBs and
to check if we have less than 'lmbs_to_remove'. We must ensure that the
entire LMB range must be removed, so we can error out immediately if any
LMB in the range is marked as reserved.

Add a couple of comments explaining the reasoning behind the differences
we have in this function in contrast to what it is done in its sister
function, dlpar_memory_remove_by_count().
Signed-off-by: NDaniel Henrique Barboza <danielhb413@gmail.com>
Reviewed-by: NDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210512202809.95363-5-danielhb413@gmail.com

After marking the LMBs as reserved depending on dlpar_remove_lmb() rc,
we evaluate whether we need to add the LMBs back or if we can release
the LMB DRCs. In both cases, a for_each_drmem_lmb() loop without a break
condition is used. This means that we're going to cycle through all LMBs
of the partition even after we're done with what we were going to do.

This patch adds break conditions in both loops to avoid this. The
'lmbs_removed' variable was renamed to 'lmbs_reserved', and it's now
being decremented each time a lmb reservation is removed, indicating
that the operation we're doing (adding back LMBs or releasing DRCs) is
completed.
Signed-off-by: NDaniel Henrique Barboza <danielhb413@gmail.com>
Reviewed-by: NDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210512202809.95363-4-danielhb413@gmail.com

DRCONF_MEM_RESERVED is a flag that represents the "Reserved Memory"
status in LOPAR v2.10, section 4.2.8. If a LMB is marked as reserved,
quoting LOPAR, "is not to be used or altered by the base OS". This flag
is read only in the kernel, being set by the firmware/hypervisor in the
DT. As an example, QEMU will set this flag in hw/ppc/spapr.c,
spapr_dt_dynamic_memory().

lmb_is_removable() does not check for DRCONF_MEM_RESERVED. This function
is used in dlpar_remove_lmb() as a guard before the removal logic. Since
it is failing to check for !RESERVED, dlpar_remove_lmb() will fail in a
later stage instead of failing in the validation when receiving a
reserved LMB as input.

lmb_is_removable() is also used in dlpar_memory_remove_by_count() to
evaluate if we have enough LMBs to complete the request. The missing
!RESERVED check in this case is causing dlpar_memory_remove_by_count()
to miscalculate the number of elegible LMBs for the removal, and can
make it error out later on instead of failing in the validation with the
'not enough LMBs to satisfy request' message.

Making a DRCONF_MEM_RESERVED check in lmb_is_removable() fixes all these
issues.
Signed-off-by: NDaniel Henrique Barboza <danielhb413@gmail.com>
Reviewed-by: NDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210512202809.95363-3-danielhb413@gmail.com

As previously done in dlpar_cpu_remove() for CPUs, this patch changes
dlpar_memory_remove_by_ic() to unisolate the LMB DRC when the LMB is
failed to be removed. The hypervisor, seeing a LMB DRC that was supposed
to be removed being unisolated instead, can do error recovery on its
side.

This change is done in dlpar_memory_remove_by_ic() only because, as of
today, only QEMU is using this code path for error recovery (via the
PSERIES_HP_ELOG_ID_DRC_IC event). phyp treats it as a no-op.
Signed-off-by: NDaniel Henrique Barboza <danielhb413@gmail.com>
Reviewed-by: NDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210512202809.95363-2-danielhb413@gmail.com

The statement of the last "if (xxx)" branch is the same as the "else"
branch. Delete it to simplify code.

No functional change.
Signed-off-by: NZhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210510131924.3907-1-thunder.leizhen@huawei.com

dlpar_memory_remove() is never used, so can be removed.
Signed-off-by: NYueHaibing <yuehaibing@huawei.com>
Reviewed-by: NDaniel Henrique Barboza <danielhb413@gmail.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210514071041.17432-1-yuehaibing@huawei.com

Currently drc_pmem_qeury_stats() generates a dev_err in case
"Enable Performance Information Collection" feature is disabled from
HMC or performance stats are not available for an nvdimm. The error is
of the form below:

papr_scm ibm,persistent-memory:ibm,pmemory@44104001: Failed to query
	 performance stats, Err:-10

This error message confuses users as it implies a possible problem
with the nvdimm even though its due to a disabled/unavailable
feature. We fix this by explicitly handling the H_AUTHORITY and
H_UNSUPPORTED errors from the H_SCM_PERFORMANCE_STATS hcall.

In case of H_AUTHORITY error an info message is logged instead of an
error, saying that "Permission denied while accessing performance
stats" and an EPERM error is returned back.

In case of H_UNSUPPORTED error we return a EOPNOTSUPP error back from
drc_pmem_query_stats() indicating that performance stats-query
operation is not supported on this nvdimm.

Fixes: 2d02bf83 ("powerpc/papr_scm: Fetch nvdimm performance stats from PHYP")
Signed-off-by: NVaibhav Jain <vaibhav@linux.ibm.com>
Reviewed-by: NIra Weiny <ira.weiny@intel.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210508043642.114076-1-vaibhav@linux.ibm.com

The hcall tracing code has a recursion check built in, which skips
tracing if we are already tracing an hcall.

However if the tracing code has problems with recursion, this check
may not catch all cases because the tracing code could be invoked from
a different tracepoint first, then make an hcall that gets traced,
then recurse.

Add an explicit warning if recursion is detected here, which might help
to notice tracing code making hcalls. Really the core trace code should
have its own recursion checking and warnings though.
Signed-off-by: NNicholas Piggin <npiggin@gmail.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210508101455.1578318-5-npiggin@gmail.com

Rather than special-case H_CEDE in the hcall trace wrappers, make the
idle H_CEDE call use plpar_hcall_norets_notrace().
Signed-off-by: NNicholas Piggin <npiggin@gmail.com>
Reviewed-by: NNaveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210508101455.1578318-4-npiggin@gmail.com

This doesn't seem very useful to trace before the recursion check, even
if the ftrace code has any recursion checks of its own. Be on the safe
side and don't trace the hcall trace wrappers.
Reported-by: NNaveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: NNicholas Piggin <npiggin@gmail.com>
Reviewed-by: NNaveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210508101455.1578318-3-npiggin@gmail.com

The paravit queued spinlock slow path adds itself to the queue then
calls pv_wait to wait for the lock to become free. This is implemented
by calling H_CONFER to donate cycles.

When hcall tracing is enabled, this H_CONFER call can lead to a spin
lock being taken in the tracing code, which will result in the lock to
be taken again, which will also go to the slow path because it queues
behind itself and so won't ever make progress.

An example trace of a deadlock:

  __pv_queued_spin_lock_slowpath
  trace_clock_global
  ring_buffer_lock_reserve
  trace_event_buffer_lock_reserve
  trace_event_buffer_reserve
  trace_event_raw_event_hcall_exit
  __trace_hcall_exit
  plpar_hcall_norets_trace
  __pv_queued_spin_lock_slowpath
  trace_clock_global
  ring_buffer_lock_reserve
  trace_event_buffer_lock_reserve
  trace_event_buffer_reserve
  trace_event_raw_event_rcu_dyntick
  rcu_irq_exit
  irq_exit
  __do_irq
  call_do_irq
  do_IRQ
  hardware_interrupt_common_virt

Fix this by introducing plpar_hcall_norets_notrace(), and using that to
make SPLPAR virtual processor dispatching hcalls by the paravirt
spinlock code.
Signed-off-by: NNicholas Piggin <npiggin@gmail.com>
Reviewed-by: NNaveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210508101455.1578318-2-npiggin@gmail.com

This code was only used by the vfio-nvlink2 code, which itself had no
proper use.  Drop this huge chunk of code build into every powernv
or generic build.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Acked-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210326061311.1497642-3-hch@lst.de

In case an nvdimm is found to be unarmed during probe then set its
NDD_UNARMED flag before nvdimm_create(). This would enforce a
read-only access to the ndimm region. Presently even if an nvdimm is
unarmed its not marked as read-only on ppc64 guests.

The patch updates papr_scm_nvdimm_init() to force query of nvdimm
health via __drc_pmem_query_health() and if nvdimm is found to be
unarmed then set the nvdimm flag ND_UNARMED for nvdimm_create().
Signed-off-by: NVaibhav Jain <vaibhav@linux.ibm.com>
Reviewed-by: NAneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210329113103.476760-1-vaibhav@linux.ibm.com

Most platforms allocate IOMMU table structures (specifically it_map)
at the boot time and when this fails - it is a valid reason for panic().

However the powernv platform allocates it_map after a device is returned
to the host OS after being passed through and this happens long after
the host OS booted. It is quite possible to trigger the it_map allocation
panic() and kill the host even though it is not necessary - the host OS
can still use the DMA bypass mode (requires a tiny fraction of it_map's
memory) and even if that fails, the host OS is runnnable as it was without
the device for which allocating it_map causes the panic.

Instead of immediately crashing in a powernv/ioda2 system, this prints
an error and continues. All other platforms still call panic().
Signed-off-by: NAlexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: NDavid Gibson <david@gibson.dropbear.id.au>
Reviewed-by: NLeonardo Bras <leobras.c@gmail.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210216033307.69863-3-aik@ozlabs.ru

As of today, if the DDW is big enough to fit (1 << MAX_PHYSMEM_BITS)
it's possible to use direct DMA mapping even with pmem region.

But, if that happens, the window size (len) is set to (MAX_PHYSMEM_BITS
- page_shift) instead of MAX_PHYSMEM_BITS, causing a pagesize times
smaller DDW to be created, being insufficient for correct usage.

Fix this so the correct window size is used in this case.

Fixes: bf6e2d56 ("powerpc/dma: Fallback to dma_ops when persistent memory present")
Signed-off-by: NLeonardo Bras <leobras.c@gmail.com>
Reviewed-by: NAlexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210420045404.438735-1-leobras.c@gmail.com

RCU complains about us calling printk() from an offline CPU:

  =============================
  WARNING: suspicious RCU usage
  5.12.0-rc7-02874-g7cf90e481cb8 #1 Not tainted
  -----------------------------
  kernel/locking/lockdep.c:3568 RCU-list traversed in non-reader section!!

  other info that might help us debug this:

  RCU used illegally from offline CPU!
  rcu_scheduler_active = 2, debug_locks = 1
  no locks held by swapper/0/0.

  stack backtrace:
  CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.12.0-rc7-02874-g7cf90e481cb8 #1
  Call Trace:
    dump_stack+0xec/0x144 (unreliable)
    lockdep_rcu_suspicious+0x124/0x144
    __lock_acquire+0x1098/0x28b0
    lock_acquire+0x128/0x600
    _raw_spin_lock_irqsave+0x6c/0xc0
    down_trylock+0x2c/0x70
    __down_trylock_console_sem+0x60/0x140
    vprintk_emit+0x1a8/0x4b0
    vprintk_func+0xcc/0x200
    printk+0x40/0x54
    pseries_cpu_offline_self+0xc0/0x120
    arch_cpu_idle_dead+0x54/0x70
    do_idle+0x174/0x4a0
    cpu_startup_entry+0x38/0x40
    rest_init+0x268/0x388
    start_kernel+0x748/0x790
    start_here_common+0x1c/0x614

Which happens because by the time we get to rtas_stop_self() we are
already offline. In addition the message can be spammy, and is not that
helpful for users, so remove it.
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210418135413.1204031-1-mpe@ellerman.id.au

Currently, neither the vio_bus or vio_driver structures provide support
for a shutdown() routine.

Add support for shutdown() by allowing drivers to provide a
implementation via function pointer in their vio_driver struct and
provide a proper implementation in the driver template for the vio_bus
that calls a vio drivers shutdown() if defined.

In the case that no shutdown() is defined by a vio driver and a kexec is
in progress we implement a big hammer that calls remove() to ensure no
further DMA for the devices is possible.
Signed-off-by: NTyrel Datwyler <tyreld@linux.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210402001325.939668-1-tyreld@linux.ibm.com