There's an H24x7_DATA_BUFFER_SIZE constant, so use it in init_24x7_request.

There's also an HV_PERF_DOMAIN_MAX constant, so use it in
h_24x7_event_init. This makes the comment above the check redundant,
so remove it.

In add_event_to_24x7_request, a statement is terminated with a comma
instead of a semicolon. Fix it.

In hv-24x7.h, improve comments in struct hv_24x7_result.

Signed-off-by: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

The H_GET_24X7_CATALOG_PAGE hcall can return a signed error code, so fix
this in the code.

The H_GET_24X7_DATA hcall can return a signed error code, so fix this in
the code. Also, don't truncate it to 32 bit to use as return value for
make_24x7_request. In case of error h_24x7_event_commit_txn passes that
return value to generic code, so it should be a proper errno. The other
caller of make_24x7_request is single_24x7_request, whose callers don't
actually care which error code is returned so they are not affected by this
change.

Finally, h_24x7_get_value doesn't use the error code from
single_24x7_request, so there's no need to store it.

Reviewed-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

make_24x7_request already calls log_24x7_hcall if it fails, so callers
don't have to do it again.

In fact, since the latter is now only called from the former, there's no
need for a separate log_24x7_hcall anymore so remove it.

Reviewed-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

hv-24x7.h has a comment mentioning that result_buffer->results can't be
indexed as a normal array because it may contain results of variable sizes,
so fix the loop in h_24x7_event_commit_txn to take the variation into
account when iterating through results.

Another problem in that loop is that it sets h24x7hw->events[i] to NULL.
This assumes that only the i'th result maps to the i'th request, but that
is not guaranteed to be true. We need to leave the event in the array so
that we don't dereference a NULL pointer in case more than one result maps
to one request.

We still assume that each result has only one result element, so warn if
that assumption is violated.

Reviewed-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

request_buffer can hold 254 requests, so if it already has that number of
entries we can't add a new one.

Also, define constant to show where the number comes from.

Fixes: e3ee15dc

 ("powerpc/perf/hv-24x7: Define add_event_to_24x7_request()")
Reviewed-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

H_GET_24X7_CATALOG_PAGE needs to be passed the version number obtained from
the first catalog page obtained previously. This is a 64 bit number, but
create_events_from_catalog truncates it to 32-bit.

This worked on POWER8, but POWER9 actually uses the upper bits so the call
fails with H_P3 because the hypervisor doesn't recognize the version.

This patch also adds the hcall return code to the error message, which is
helpful when debugging the problem.

Fixes: 5c5cd7b5

 ("powerpc/perf/hv-24x7: parse catalog and populate sysfs with events")
Reviewed-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Flip the switch. Running around and screaming "IT'S ALIVE" is optional,
but recommended.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Adds support for removing bolted (i.e kernel linear mapping) mappings on
powernv. This is needed to support memory hot unplug operations which
are required for the teardown of DAX/PMEM devices.

Reviewed-by: Balbir Singh <bsingharora@gmail.com>
Reviewed-by: Rashmica Gupta <rashmica.g@gmail.com>
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Add support for the devmap bit on PTEs and PMDs for PPC64 Book3S.  This
is used to differentiate device backed memory from transparent huge
pages since they are handled in more or less the same manner by the core
mm code.

Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Adds support to powerpc for the altmap feature of ZONE_DEVICE memory. An
altmap is a driver provided region that is used to provide the backing
storage for the struct pages of ZONE_DEVICE memory. In situations where
large amount of ZONE_DEVICE memory is being added to the system the
altmap reduces pressure on main system memory by allowing the mm/
metadata to be stored on the device itself rather in main memory.

Reviewed-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Removes an indentation level and shuffles some code around to make the
following patch cleaner. No functional changes.

Reviewed-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Currently ZONE_DEVICE depends on X86_64 and this will get unwieldly as
new architectures (and platforms) get ZONE_DEVICE support. Move to an
arch selected Kconfig option to save us the trouble.

Cc: linux-mm@kvack.org
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Export it so it can be referenced inside a module.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

As Ian's stepping down from his maintainer role now that he's leaving IBM,
Frederic has asked me to add myself to the cxl maintainer list. Updating
accordingly.

Cc: Frederic Barrat <fbarrat@linux.vnet.ibm.com>
Cc: Ian Munsie <imunsie@au1.ibm.com>
Signed-off-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Acked-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com>
Acked-by: Ian Munsie <imunsie@au1.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

I am no longer employed by IBM and will no longer have access to cxl
hardware, so remove myself as a cxl maintainer.

If anyone needs to contact me in the future, please use my personal
email address darkstarsword@gmail.com

Signed-off-by: Ian Munsie <imunsie@au1.ibm.com>
Cc: Frederic Barrat <fbarrat@linux.vnet.ibm.com>
Cc: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Cc: linuxppc-dev@lists.ozlabs.org
Acked-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Use the different spin loop primitives in some simple powerpc
spin loops, including those which will spin as a common case.

This will help to test the spin loop primitives before more
conversions are done.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Add some includes of <linux/processor.h>]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Current busy-wait loops are implemented by repeatedly calling cpu_relax()
to give an arch option for a low-latency option to improve power and/or
SMT resource contention.

This poses some difficulties for powerpc, which has SMT priority setting
instructions (priorities determine how ifetch cycles are apportioned).
powerpc's cpu_relax() is implemented by setting a low priority then
setting normal priority. This has several problems:

 - Changing thread priority can have some execution cost and potential
   impact to other threads in the core. It's inefficient to execute them
   every time around a busy-wait loop.

 - Depending on implementation details, a `low ; medium` sequence may
   not have much if any affect. Some software with similar pattern
   actually inserts a lot of nops between, in order to cause a few fetch
   cycles with the low priority.

 - The busy-wait loop runs with regular priority. This might only be a few
   fetch cycles, but if there are several threads running such loops, they
   could cause a noticable impact on a non-idle thread.

Implement spin_begin, spin_end primitives that can be used around busy
wait loops, which default to no-ops. And spin_cpu_relax which defaults to
cpu_relax.

This will allow architectures to hook the entry and exit of busy-wait
loops, and will allow powerpc to set low SMT priority at entry, and
normal priority at exit.

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

pnv_wakeup_noloss() expects r12 to contain SRR1 value to determine if the wakeup
reason is an HMI in CHECK_HMI_INTERRUPT.

When we wakeup with ESL=0, SRR1 will not contain the wakeup reason, so there is
no point setting r12 to SRR1.

However, we don't set r12 at all so r12 contains garbage (likely a kernel
pointer), and is still used to check HMI assuming that it contained SRR1. This
causes the OPAL msglog to be filled with the following print:

  HMI: Received HMI interrupt: HMER = 0x0040000000000000

This patch clears r12 after waking up from stop with ESL=EC=0, so that we don't
accidentally enter the HMI handler in pnv_wakeup_noloss() if the value of
r12[42:45] corresponds to HMI as wakeup reason.

Prior to commit 9d292501 ("powerpc/64s/idle: Avoid SRR usage in idle
sleep/wake paths") this bug existed, in that we would incorrectly look at SRR1
to check for a HMI when SRR1 didn't contain a wakeup reason. However the SRR1
value would just happen to never have bits 42:45 set.

Fixes: 9d292501

 ("powerpc/64s/idle: Avoid SRR usage in idle sleep/wake paths")
Signed-off-by: Akshay Adiga <akshay.adiga@linux.vnet.ibm.com>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Change log and comment massaging]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Adds some explaination on how the vmemmap based struct page layout's
physical mapping is allocated and tracked through linked list. It
also keeps note of a possible race condition.

Signed-off-by: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Add some explaination to the layout of vmemmap virtual address
space and how physical page mapping is only used for valid PFNs
present at any point on the system.

Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

nr_cpu_ids can be limited by nr_cpus boot parameter, whereas NR_CPUS is a
compile time constant, which shouldn't be compared against during cpu kick.

Signed-off-by: Santosh Sivaraj <santosh@fossix.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

During secondary start, we do not need to BUG_ON if an invalid CPU number
is passed. We already print an error if secondary cannot be started, so
just return an error instead.

Signed-off-by: Santosh Sivaraj <santosh@fossix.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

The at24 driver allows to register I2C EEPROM chips using different vendor
and devices, but the I2C subsystem does not take the vendor into account
when matching using the I2C table since it only has device entries.

But when matching using an OF table, both the vendor and device has to be
taken into account so the driver defines only a set of compatible strings
using the "atmel" vendor as a generic fallback for compatible I2C devices.

So add this generic fallback to the device node compatible string to make
the device to match the driver using the OF device ID table.

Signed-off-by: Javier Martinez Canillas <javier@dowhile0.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

The at24 driver allows to register I2C EEPROM chips using different vendor
and devices, but the I2C subsystem does not take the vendor into account
when matching using the I2C table since it only has device entries.

But when matching using an OF table, both the vendor and device has to be
taken into account so the driver defines only a set of compatible strings
using the "atmel" vendor as a generic fallback for compatible I2C devices.

So add this generic fallback to the device node compatible string to make
the device to match the driver using the OF device ID table.

Signed-off-by: Javier Martinez Canillas <javier@dowhile0.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

The at24 driver allows to register I2C EEPROM chips using different vendor
and devices, but the I2C subsystem does not take the vendor into account
when matching using the I2C table since it only has device entries.

But when matching using an OF table, both the vendor and device has to be
taken into account so the driver defines only a set of compatible strings
using the "atmel" vendor as a generic fallback for compatible I2C devices.

So add this generic fallback to the device node compatible string to make
the device to match the driver using the OF device ID table.

Signed-off-by: Javier Martinez Canillas <javier@dowhile0.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

The at24 driver allows to register I2C EEPROM chips using different vendor
and devices, but the I2C subsystem does not take the vendor into account
when matching using the I2C table since it only has device entries.

But when matching using an OF table, both the vendor and device has to be
taken into account so the driver defines only a set of compatible strings
using the "atmel" vendor as a generic fallback for compatible I2C devices.

So add this generic fallback to the device node compatible string to make
the device to match the driver using the OF device ID table.

Signed-off-by: Javier Martinez Canillas <javier@dowhile0.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

The at24 driver allows to register I2C EEPROM chips using different vendor
and devices, but the I2C subsystem does not take the vendor into account
when matching using the I2C table since it only has device entries.

But when matching using an OF table, both the vendor and device has to be
taken into account so the driver defines only a set of compatible strings
using the "atmel" vendor as a generic fallback for compatible I2C devices.

So add this generic fallback to the device node compatible string to make
the device to match the driver using the OF device ID table.

Signed-off-by: Javier Martinez Canillas <javier@dowhile0.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

A memory barrier is not required after the task wakes up,
only if we clear the polling flag before waking. The case
where we have work to do is the important one, so optimise
for it.

Reviewed-by: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Ensure these don't get put into bouncing cachelines.

Reviewed-by: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

local_irq_enable can cause interrupts to be taken which could
take significant amount of processing time. The idle process
should set its polling flag before this, so another process that
wakes it during this time will not have to send an IPI.

Expand the TIF_POLLING_NRFLAG coverage to as large as possible.

Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Around 95% of memory is reserved by fadump/capture kernel. All this
memory is freed, one page at a time, on writing '1' to the node
/sys/kernel/fadump_release_mem. On systems with large memory, this
can take a long time to complete, leading to soft lockup warning
messages. To avoid this, add reschedule points at regular intervals.

Also, while memblock_reserve() implicitly takes care of holes in the
given memory range while reserving memory, those holes need to be
taken care of while releasing memory as memory is freed one page at
a time. Add support to skip holes while releasing memory.

Suggested-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Hari Bathini <hbathini@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

fadump fails to register when there are holes in boot memory area.
Provide a helpful error message to the user in such case.

Signed-off-by: Hari Bathini <hbathini@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

To register fadump, boot memory area - the size of low memory chunk that
is required for a kernel to boot successfully when booted with restricted
memory, is assumed to have no holes. But this memory area is currently
not protected from hot-remove operations. So, fadump could fail to
re-register after a memory hot-remove operation, if memory is removed
from boot memory area. To avoid this, ensure that memory from boot
memory area is not hot-removed when fadump is registered.

Signed-off-by: Hari Bathini <hbathini@linux.vnet.ibm.com>
Reviewed-by: Mahesh J Salgaonkar <mahesh@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

fadump sets up crash memory ranges to be used for creating PT_LOAD
program headers in elfcore header. Memory chunk RMA_START through
boot memory area size is added as the first memory range because
firmware, at the time of crash, moves this memory chunk to different
location specified during fadump registration making it necessary to
create a separate program header for it with the correct offset.
This memory chunk is skipped while setting up the remaining memory
ranges. But currently, there is possibility that some of this memory
may have duplicate entries like when it is hot-removed and added
again. Ensure that no two memory ranges represent the same memory.

When 5 lmbs are hot-removed and then hot-plugged before registering
fadump, here is how the program headers in /proc/vmcore exported by
fadump look like

without this change:

  Program Headers:
    Type           Offset             VirtAddr           PhysAddr
                   FileSiz            MemSiz              Flags  Align
    NOTE           0x0000000000010000 0x0000000000000000 0x0000000000000000
                   0x0000000000001894 0x0000000000001894         0
    LOAD           0x0000000000021020 0xc000000000000000 0x0000000000000000
                   0x0000000040000000 0x0000000040000000  RWE    0
    LOAD           0x0000000040031020 0xc000000000000000 0x0000000000000000
                   0x0000000010000000 0x0000000010000000  RWE    0
    LOAD           0x0000000050040000 0xc000000010000000 0x0000000010000000
                   0x0000000050000000 0x0000000050000000  RWE    0
    LOAD           0x00000000a0040000 0xc000000060000000 0x0000000060000000
                   0x000000019ffe0000 0x000000019ffe0000  RWE    0

and with this change:

  Program Headers:
    Type           Offset             VirtAddr           PhysAddr
                   FileSiz            MemSiz              Flags  Align
    NOTE           0x0000000000010000 0x0000000000000000 0x0000000000000000
                   0x0000000000001894 0x0000000000001894         0
    LOAD           0x0000000000021020 0xc000000000000000 0x0000000000000000
                   0x0000000040000000 0x0000000040000000  RWE    0
    LOAD           0x0000000040030000 0xc000000040000000 0x0000000040000000
                   0x0000000020000000 0x0000000020000000  RWE    0
    LOAD           0x0000000060030000 0xc000000060000000 0x0000000060000000
                   0x000000019ffe0000 0x000000019ffe0000  RWE    0

Signed-off-by: Hari Bathini <hbathini@linux.vnet.ibm.com>
Reviewed-by: Mahesh J Salgaonkar <mahesh@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Correct "branch" event code of Power9 is "r4d05e". Replace the current
"branch" event code with "r4d05e" and add a hack to use "r10012" as
event code for Power9 DD1.

Fixes: d89f473f

 ("powerpc/perf: Fix PM_BRU_CMPL event code for power9")
Reported-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

There is no reason for that message to be pr_info(), it will be printed
every time we start a KVM guest.

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

On POWER9 the ERAT may be incorrect on wakeup from some stop states
that lose state. This causes random segvs and illegal instructions
when these stop states are enabled.

This patch invalidates the ERAT on wakeup on POWER9 to prevent this
from causing a problem.

Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Merge comment change with upstream changes]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

From: Michael Neuling <mikey@neuling.org>

On P9 (Nimbus) DD2 and later, in radix mode, the move to the PID
register will implicitly invalidate the user space ERAT entries
and leave the kernel ones alone. Thus the only thing needed is
an isync() to synchronize this with subsequent uaccess's

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

On PHB3/POWER8 systems, devices can select between two different sections
of address space, TVE#0 and TVE#1.  TVE#0 is intended for 32bit devices
that aren't capable of addressing more than 4GB.  Selecting TVE#1 instead,
with the capability of addressing over 4GB, is performed by setting bit 59
of a PCI address.

However, some devices aren't capable of addressing at least 59 bits, but
still want more than 4GB of DMA space.  In order to enable this, reconfigure
TVE#0 to be suitable for 64-bit devices by allocating memory past the
initial 4GB that is inaccessible by 64-bit DMAs.

This bypass mode is only enabled if a device requests 4GB or more of DMA
address space, if the system has PHB3 (POWER8 systems), and if the device
does not share a PE with any devices from different vendors.

Signed-off-by: Russell Currey <ruscur@russell.cc>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>