Naveen N. Rao [Thu, 29 Jun 2017 17:49:17 +0000 (23:19 +0530)]
powerpc/64s: Move system_call() symbol to just after setting MSR_EE
It is common to get a PMU interrupt right after the mtmsr instruction that
enables interrupts. Due to this, the stack trace profile gets needlessly split
across system_call_common() and system_call().
Previously, system_call() symbol was at the current place to hide a few
earlier symbols which have since been made private or removed entirely.
So, let's move system_call() slightly higher up, right after the mtmsr
instruction that enables interrupts. Convert existing references to
system_call to a local syscall symbol.
Suggested-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Naveen N. Rao [Thu, 29 Jun 2017 17:49:16 +0000 (23:19 +0530)]
powerpc/64s: Blacklist system_call() and system_call_common() from kprobes
Convert some of the symbols into private symbols and blacklist
system_call_common() and system_call() from kprobes. We can't take a
trap at parts of these functions as either MSR_RI is unset or the
kernel stack pointer is not yet setup.
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
[mpe: Don't convert system_call_common to _GLOBAL()] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Naveen N. Rao [Thu, 29 Jun 2017 17:49:15 +0000 (23:19 +0530)]
powerpc/64s: Convert .L__replay_interrupt_return to a local label
Commit b48bbb82e2b835 ("powerpc/64s: Don't unbalance the return branch
predictor in __replay_interrupt()") introduced __replay_interrupt_return
symbol with '.L' prefix in hopes of keeping it private. However, due to
the use of LOAD_REG_ADDR(), the assembler kept this symbol visible. Fix
the same by instead using the local label '1'.
Fixes: Commit b48bbb82e2b835 ("powerpc/64s: Don't unbalance the return branch
predictor in __replay_interrupt()") Suggested-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Naveen N. Rao [Thu, 29 Jun 2017 17:49:14 +0000 (23:19 +0530)]
powerpc64/elfv1: Only dereference function descriptor for non-text symbols
Currently, we assume that the function pointer we receive in
ppc_function_entry() points to a function descriptor. However, this is
not always the case. In particular, assembly symbols without the right
annotation do not have an associated function descriptor. Some of these
symbols are added to the kprobe blacklist using _ASM_NOKPROBE_SYMBOL().
When such addresses are subsequently processed through
arch_deref_entry_point() in populate_kprobe_blacklist(), we see the
below errors during bootup:
[ 0.663963] Failed to find blacklist at 7d9b02a648029b6c
[ 0.663970] Failed to find blacklist at a14d03d0394a0001
[ 0.663972] Failed to find blacklist at 7d5302a6f94d0388
[ 0.663973] Failed to find blacklist at 48027d11e8610178
[ 0.663974] Failed to find blacklist at f8010070f8410080
[ 0.663976] Failed to find blacklist at 386100704801f89d
[ 0.663977] Failed to find blacklist at 7d5302a6f94d00b0
Fix this by checking if the function pointer we receive in
ppc_function_entry() already points to kernel text. If so, we just
return it as is. If not, we assume that this is a function descriptor
and proceed to dereference it.
Suggested-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This patch exports a in-kernel 'library' API which can be called by
other drivers to help interacting with an IBM XSL on a POWER9 system.
The XSL (Translation Service Layer) is a stripped down version of the
PSL (Power Service Layer) used in some cards such as the Mellanox CX5.
Like the PSL, it implements the CAIA architecture, but has a number
of differences, mostly in it's implementation dependent registers.
The XSL also uses a special DMA cxl mode, which uses a slightly
different init sequence for the CAPP and PHB.
Signed-off-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com> Signed-off-by: Christophe Lombard <clombard@linux.vnet.ibm.com> Acked-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Merge our fixes branch, a few of them are tripping people up while
working on top of next, and we also have a dependency between the CXL
fixes and new CXL code we want to merge into next.
Masahiro Yamada [Wed, 24 May 2017 05:12:24 +0000 (14:12 +0900)]
powerpc/dts: Use #include "..." to include local DT
Most of DT files in PowerPC use #include "..." to make pre-processor
include DT in the same directory, but we have 3 exceptional files
that use #include <...> for that.
Fix them to remove -I$(srctree)/arch/$(SRCARCH)/boot/dts path from
dtc_cpp_flags.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
powerpc/perf/hv-24x7: Aggregate result elements on POWER9 SMT8
On POWER9 SMT8 the 24x7 API returns two result elements for physical core
and virtual CPU events and we need to add their counts to get the final
result.
powerpc/perf/hv-24x7: Support v2 of the hypervisor API
POWER9 introduces a new version of the hypervisor API to access the 24x7
perf counters. The new version changed some of the structures used for
requests and results.
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.
powerpc/perf/hv-24x7: Properly iterate through results
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.
powerpc/perf/hv-24x7: Fix passing of catalog version number
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: 5c5cd7b50259 ("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>
Anton Blanchard [Wed, 28 Jun 2017 01:32:35 +0000 (11:32 +1000)]
powerpc/mm: Wire up hpte_removebolted for powernv
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>
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>
Andrew Donnellan [Wed, 28 Jun 2017 07:22:30 +0000 (17:22 +1000)]
MAINTAINERS: cxl: update maintainership
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>
Nicholas Piggin [Tue, 6 Jun 2017 13:08:32 +0000 (23:08 +1000)]
powerpc: use spin loop primitives in some functions
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>
Nicholas Piggin [Mon, 29 May 2017 02:22:23 +0000 (12:22 +1000)]
spin loop primitives for busy waiting
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>
Akshay Adiga [Wed, 28 Jun 2017 01:16:49 +0000 (06:46 +0530)]
powerpc/powernv/idle: Clear r12 on wakeup from stop lite
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 9d29250136f6 ("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: 9d29250136f6 ("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>
powerpc/mm: Add comments on vmemmap physical mapping
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.
Santosh Sivaraj [Tue, 27 Jun 2017 07:00:05 +0000 (12:30 +0530)]
powerpc/smp: Do not BUG_ON if invalid CPU during kick
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>
powerpc/44x: Add generic compatible string for I2C EEPROM
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>
powerpc/83xx: Add generic compatible string for I2C EEPROM
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>
powerpc/512x: Add generic compatible string for I2C EEPROM
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>
powerpc/fsl: Add generic compatible string for I2C EEPROM
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>
powerpc/5200: Add generic compatible string for I2C EEPROM
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>
Nicholas Piggin [Wed, 14 Jun 2017 13:02:41 +0000 (23:02 +1000)]
cpuidle: powerpc: no memory barrier after break from idle
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>
Nicholas Piggin [Wed, 14 Jun 2017 13:02:39 +0000 (23:02 +1000)]
cpuidle: powerpc: cpuidle set polling before enabling irqs
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>
Hari Bathini [Thu, 1 Jun 2017 19:40:10 +0000 (01:10 +0530)]
powerpc/fadump: add reschedule point while releasing memory
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>
Hari Bathini [Thu, 1 Jun 2017 17:21:26 +0000 (22:51 +0530)]
powerpc/fadump: avoid holes in boot memory area when fadump is registered
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>
Hari Bathini [Thu, 1 Jun 2017 17:20:38 +0000 (22:50 +0530)]
powerpc/fadump: avoid duplicates in crash memory ranges
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
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: d89f473ff6f8 ("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>
powerpc/64s: Invalidate ERAT on powersave wakeup for POWER9
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>
powerpc: Only do ERAT invalidate on radix context switch on P9 DD1
From:Â 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>
Russell Currey [Wed, 21 Jun 2017 07:18:04 +0000 (17:18 +1000)]
powerpc/powernv/pci: Enable 64-bit devices to access >4GB DMA space
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>
Russell Currey [Wed, 21 Jun 2017 07:18:03 +0000 (17:18 +1000)]
powerpc/powernv/pci: Add helper to check if a PE has a single vendor
Add a helper that determines if all the devices contained in a given PE
are all from the same vendor or not. This can be useful in determining
if it's okay to make PE-wide changes that may be suitable for some
devices but not for others.
This is used later in the series.
Signed-off-by: Russell Currey <ruscur@russell.cc> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Russell Currey [Wed, 14 Jun 2017 04:19:59 +0000 (14:19 +1000)]
powerpc/powernv/pci: Dynamically allocate PHB diag data
Diagnostic data for PHBs currently works by allocated a fixed-sized buffer.
This is simple, but either wastes memory (though only a few kilobytes) or
in the case of PHB4 isn't enough to fit the whole data blob.
For machines that don't describe the diagnostic data size in the device
tree, use the hardcoded buffer size as before. For those that do, only
allocate exactly what's needed.
In the special case of P7IOC (which has two types of diag data), the larger
should be specified in the device tree.
Signed-off-by: Russell Currey <ruscur@russell.cc> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Russell Currey [Wed, 14 Jun 2017 04:19:58 +0000 (14:19 +1000)]
powerpc/powernv/pci: Reduce spam when dumping PEST
Dumping the PE State Tables (PEST) can be highly verbose if a number of PEs
are affected, especially in the case where the whole PHB is frozen and 512
lines get printed. Check for duplicates when dumping the PEST to reduce
useless output.
Michael Neuling [Mon, 8 May 2017 06:23:31 +0000 (16:23 +1000)]
powerpc: Fix asm offsets to point to actual FP and VMX regs
The asm code assumes the FP regs are at the start of fp_state. While
this is true now, it may not always be the case and there is nothing
enforcing it.
This fixes the asm-offsets to point to the actual FP registers inside
the fp_state. Similarly for VMX.
Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Michael Neuling [Thu, 15 Jun 2017 01:53:16 +0000 (11:53 +1000)]
powerpc: Fix /proc/cpuinfo revision for POWER9 DD2
The P9 PVR bits 12-15 don't indicate a revision but instead different
chip configurations. From BookIV we have:
Bits Configuration
0 : Scale out 12 cores
1 : Scale out 24 cores
2 : Scale up 12 cores
3 : Scale up 24 cores
DD1 doesn't use this but DD2 does. Linux will mostly use the "Scale
out 24 core" configuration (ie. SMT4 not SMT8) which results in a PVR
of 0x004e1200. The reported revision in /proc/cpuinfo is hence
reported incorrectly as "18.0".
This patch fixes this to mask off only the relevant bits for the major
revision (ie. bits 8-11) for POWER9.
Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Larry Finger reported that his Powerbook G4 was no longer booting with v4.12-rc,
userspace was up but giving weird errors such as:
udevd[64]: starting version 175
udevd[64]: Unable to receive ctrl message: Bad address.
modprobe: chdir(4.12-rc1): No such file or directory
He bisected the problem to commit 3448890c32c3 ("powerpc: get rid of zeroing,
switch to RAW_COPY_USER").
Al identified that the problem is actually a miscompilation by GCC 4.6.3, which
is exposed by the above commit.
Al also pointed out that inlining copy_to/from_user() is probably of little or
no benefit, which is correct. Using Anton's copy_to_user benchmark, with a
pathological single byte copy, we see a small increase in performance
by *removing* inlining:
Before (inlined):
# time ./copy_to_user -w -l 1 -i 10000000 ( x 3 )
real 0m22.063s
real 0m22.059s
real 0m22.076s
After:
# time ./copy_to_user -w -l 1 -i 10000000 ( x 3 )
real 0m21.325s
real 0m21.299s
real 0m21.364s
So as a small performance improvement and to avoid the miscompilation, drop
inlining copy_to/from_user() on 32-bit.
Fixes: 3448890c32c3 ("powerpc: get rid of zeroing, switch to RAW_COPY_USER") Reported-by: Larry Finger <Larry.Finger@lwfinger.net> Suggested-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Add a trace point for tlbie(l) (Translation Lookaside Buffer Invalidate
Entry (Local)) instructions.
The tlbie instruction has changed over the years, so not all versions
accept the same operands. Use the ISA v3 field operands because they are
the most verbose, we may change them in future.
Example output:
qemu-system-ppc-5371 [016] 1412.369519: tlbie:
tlbie with lpid 0, local 1, rb=67bd8900174c11c1, rs=0, ric=0 prs=0 r=0
Signed-off-by: Balbir Singh <bsingharora@gmail.com>
[mpe: Add some missing trace_tlbie()s, reword change log] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
cxl: Fixes for Coherent Accelerator Interface Architecture 2.0
A previous set of patches "cxl: Add support for Coherent Accelerator
Interface Architecture 2.0" has introduced a new support for the CAPI
cards. These patches have been tested on Simulation environment and
quite a bit of them have been tested on real hardware.
This patch brings new fixes after a series of tests carried out on new
equipment:
- Add POWER9 definition.
- Re-enable any masked interrupts when the AFU is not activated
after resetting the AFU.
- Remove the api cxl_is_psl8/9 which is no longer useful.
- Do not dump CAPI1 registers.
- Rewrite cxl_is_page_fault() function.
- Do not register slb callack on P9.
Fixes: f24be42aab37 ("cxl: Add psl9 specific code") Signed-off-by: Christophe Lombard <clombard@linux.vnet.ibm.com> Acked-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Nicholas Piggin [Wed, 21 Jun 2017 05:58:29 +0000 (15:58 +1000)]
powerpc/64: Initialise thread_info for emergency stacks
Emergency stacks have their thread_info mostly uninitialised, which in
particular means garbage preempt_count values.
Emergency stack code runs with interrupts disabled entirely, and is
used very rarely, so this has been unnoticed so far. It was found by a
proposed new powerpc watchdog that takes a soft-NMI directly from the
masked_interrupt handler and using the emergency stack. That crashed
at BUG_ON(in_nmi()) in nmi_enter(). preempt_count()s were found to be
garbage.
To fix this, zero the entire THREAD_SIZE allocation, and initialize
the thread_info.
Cc: stable@vger.kernel.org Reported-by: Abdul Haleem <abdhalee@linux.vnet.ibm.com> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Move it all into setup_64.c, use a function not a macro. Fix
crashes on Cell by setting preempt_count to 0 not HARDIRQ_OFFSET] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Alistair Popple [Tue, 20 Jun 2017 08:37:28 +0000 (18:37 +1000)]
powerpc/powernv/npu-dma: Add explicit flush when sending an ATSD
NPU2 requires an extra explicit flush to an active GPU PID when
sending address translation shoot downs (ATSDs) to reliably flush the
GPU TLB. This patch adds just such a flush at the end of each sequence
of ATSDs.
We can safely use PID 0 which is always reserved and active on the
GPU. PID 0 is only used for init_mm which will never be a user mm on
the GPU. To enforce this we add a check in pnv_npu2_init_context()
just in case someone tries to use PID 0 on the GPU.
Signed-off-by: Alistair Popple <alistair@popple.id.au>
[mpe: Use true/false for bool literals] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Paul Mackerras [Sat, 27 May 2017 08:04:52 +0000 (18:04 +1000)]
powerpc: Convert VDSO update function to use new update_vsyscall interface
This converts the powerpc VDSO time update function to use the new
interface introduced in commit 576094b7f0aa ("time: Introduce new
GENERIC_TIME_VSYSCALL", 2012-09-11). Where the old interface gave
us the time as of the last update in seconds and whole nanoseconds,
with the new interface we get the nanoseconds part effectively in
a binary fixed-point format with tk->tkr_mono.shift bits to the
right of the binary point.
With the old interface, the fractional nanoseconds got truncated,
meaning that the value returned by the VDSO clock_gettime function
would have about 1ns of jitter in it compared to the value computed
by the generic timekeeping code in the kernel.
The powerpc VDSO time functions (clock_gettime and gettimeofday)
already work in units of 2^-32 seconds, or 0.23283 ns, because that
makes it simple to split the result into seconds and fractional
seconds, and represent the fractional seconds in either microseconds
or nanoseconds. This is good enough accuracy for now, so this patch
avoids changing how the VDSO works or the interface in the VDSO data
page.
This patch converts the powerpc update_vsyscall_old to be called
update_vsyscall and use the new interface. We convert the fractional
second to units of 2^-32 seconds without truncating to whole nanoseconds.
(There is still a conversion to whole nanoseconds for any legacy users
of the vdso_data/systemcfg stamp_xtime field.)
In addition, this improves the accuracy of the computation of tb_to_xs
for those systems with high-frequency timebase clocks (>= 268.5 MHz)
by doing the right shift in two parts, one before the multiplication and
one after, rather than doing the right shift before the multiplication.
(We can't do all of the right shift after the multiplication unless we
use 128-bit arithmetic.)
Signed-off-by: Paul Mackerras <paulus@ozlabs.org> Acked-by: John Stultz <john.stultz@linaro.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Santosh Sivaraj [Tue, 20 Jun 2017 07:44:47 +0000 (13:14 +0530)]
powerpc/time: Fix tracing in time.c
Since trace_clock is in a different file and already marked with notrace,
enable tracing in time.c by removing it from the disabled list in Makefile.
Also annotate clocksource read functions and sched_clock with notrace.
Testing: Timer and ftrace selftests run with different trace clocks.
Acked-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Santosh Sivaraj <santosh@fossix.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Michael Ellerman [Mon, 19 Jun 2017 11:47:11 +0000 (21:47 +1000)]
powerpc/64s: Use BRANCH_TO_COMMON() for slb_miss_realmode
All the callers of slb_miss_realmode currently open code the #ifndef
CONFIG_RELOCATABLE check and the branch via CTR in the RELOCATABLE case.
We have a macro to do this, BRANCH_TO_COMMON(), so use it.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Nicholas Piggin [Sun, 21 May 2017 13:15:46 +0000 (23:15 +1000)]
powerpc/64s: Add EX_SIZE definition for paca exception save areas
Rather than open-coding it 4 times.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Move __ASSEMBLY__ guards into head-64.h where they're really needed] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Nicholas Piggin [Sun, 21 May 2017 13:15:45 +0000 (23:15 +1000)]
powerpc/64s: Avoid r3 save/restore in SLB miss handler
The SLB miss handler uses r3 for the faulting address but r12 is
mostly able to be freed up to save r3 in. It just requires SRR1
be reloaded again on error.
It would be more conventional to use r12 for SRR1 (and use r11 to
save r3), but slb_allocate_realmode clobbers r11 and not r12.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Nicholas Piggin [Sun, 21 May 2017 13:15:44 +0000 (23:15 +1000)]
powerpc/64s: SLB miss already has CTR saved for relocatable kernel
The EXCEPTION_PROLOG_1 used by SLB miss already saves CTR when the
kernel is built with CONFIG_RELOCATABLE. So it does not have to be
saved and reloaded when branching to slb_miss_realmode. It can be
restored from the PACA as usual.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Nicholas Piggin [Sun, 21 May 2017 13:15:43 +0000 (23:15 +1000)]
powerpc/64s: Avoid saving faulting address into EX_DAR in SLB miss
The EX_DAR save area is only used in exceptional cases. With r3 no
longer clobbered by slb_allocate_realmode, saving faulting address to
EX_DAR can be deferred to those cases.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Nicholas Piggin [Tue, 13 Jun 2017 13:05:57 +0000 (23:05 +1000)]
powerpc/64s/idle: Run latch switch is done with MSR[EE]=0
In the idle sleep/wake code we know that MSR[EE] is clear, so we can
avoid 2 x mfmsr and 2 x mtmsr by calling the double-underscore
versions of the run latch routines which assume interrupts are already
disabled.
Acked-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>
Nicholas Piggin [Tue, 13 Jun 2017 13:05:52 +0000 (23:05 +1000)]
powerpc/64s/idle: Predict HMI wakeup as unlikely
In a busy system, idle wakeups can be expected from IPIs and device
interrupts.
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>
Nicholas Piggin [Tue, 13 Jun 2017 13:05:51 +0000 (23:05 +1000)]
powerpc/64s/idle: Avoid SRR usage in idle sleep/wake paths
Idle code now always runs at the 0xc... effective address whether
in real or virtual mode. This means rfid can be ditched, along
with a lot of SRR manipulations.
In the wakeup path, carry SRR1 around in r12. Use mtmsrd to change
MSR states as required.
This also balances the return prediction for the idle call, by
doing blr rather than rfid to return to the idle caller.
On POWER9, 2-process context switch on different cores, with snooze
disabled, increases performance by 2%.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Incorporate v2 fixes from Nick] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Nicholas Piggin [Tue, 13 Jun 2017 13:05:50 +0000 (23:05 +1000)]
powerpc/64s/idle: Branch to handler with virtual mode offset
Have the system reset idle wakeup handlers branched to in real mode
with the 0xc... kernel address applied. This allows simplifications of
avoiding rfid when switching to virtual mode in the wakeup handler.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Nicholas Piggin [Tue, 13 Jun 2017 13:05:49 +0000 (23:05 +1000)]
powerpc/64s: Don't unbalance the return branch predictor in __replay_interrupt()
The __replay_interrupt() code is branched to with bl, but the caller is
returned to directly with rfid from the interrupt.
Instead, rfid to a stub that returns to the caller with blr, which
should keep the return branch predictor balanced.
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>
Nicholas Piggin [Tue, 13 Jun 2017 13:05:48 +0000 (23:05 +1000)]
powerpc/64s: msgclr when handling doorbell exceptions from system reset
msgsnd doorbell exceptions are cleared when the doorbell interrupt is
taken. However if a doorbell exception causes a system reset interrupt
wake from power saving state, the message is not cleared. Processing
the doorbell from the system reset interrupt requires msgclr to avoid
taking the exception again.
Testing this plus the previous wakup direct patch gives:
original wakeup direct msgclr
Different threads, same core: 315k/s 264k/s 345k/s
Different cores: 235k/s 242k/s 242k/s
Net speedup is +10% for same core, and +3% for different core.
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>
Nicholas Piggin [Tue, 13 Jun 2017 13:05:47 +0000 (23:05 +1000)]
powerpc/64s/idle: Process interrupts from system reset wakeup
When the CPU wakes from low power state, it begins at the system reset
interrupt with the exception that caused the wakeup encoded in SRR1.
Today, powernv idle wakeup ignores the wakeup reason (except a special
case for HMI), and the regular interrupt corresponding to the
exception will fire after the idle wakeup exits.
Change this to replay the interrupt from the idle wakeup before
interrupts are hard-enabled.
Test on POWER8 of context_switch selftests benchmark with polling idle
disabled (e.g., always nap, giving cross-CPU IPIs) gives the following
results:
original wakeup direct
Different threads, same core: 315k/s 264k/s
Different cores: 235k/s 242k/s
There is a slowdown for doorbell IPI (same core) case because system
reset wakeup does not clear the message and the doorbell interrupt
fires again needlessly.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Nicholas Piggin [Tue, 13 Jun 2017 13:05:46 +0000 (23:05 +1000)]
powerpc/powernv: Simplify lazy IRQ handling in CPU offline
Rather than concern ourselves with any soft-mask logic in the CPU
hotplug handler, just hard disable interrupts. This ensures there
are no lazy-irqs pending, which means we can call directly to idle
instruction in order to sleep.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Nicholas Piggin [Tue, 13 Jun 2017 13:05:45 +0000 (23:05 +1000)]
powerpc/64s/idle: Move soft interrupt mask logic into C code
This simplifies the asm and fixes irq-off tracing over sleep
instructions.
Also move powersave_nap check for POWER8 into C code, and move
PSSCR register value calculation for POWER9 into C.
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>
Ravi Bangoria [Thu, 15 Jun 2017 13:46:48 +0000 (19:16 +0530)]
powerpc/perf: Fix oops when kthread execs user process
When a kthread calls call_usermodehelper() the steps are:
1. allocate current->mm
2. load_elf_binary()
3. populate current->thread.regs
While doing this, interrupts are not disabled. If there is a perf
interrupt in the middle of this process (i.e. step 1 has completed
but not yet reached to step 3) and if perf tries to read userspace
regs, kernel oops with following log:
Unable to handle kernel paging request for data at address 0x00000000
Faulting instruction address: 0xc0000000000da0fc
...
Call Trace:
perf_output_sample_regs+0x6c/0xd0
perf_output_sample+0x4e4/0x830
perf_event_output_forward+0x64/0x90
__perf_event_overflow+0x8c/0x1e0
record_and_restart+0x220/0x5c0
perf_event_interrupt+0x2d8/0x4d0
performance_monitor_exception+0x54/0x70
performance_monitor_common+0x158/0x160
--- interrupt: f01 at avtab_search_node+0x150/0x1a0
LR = avtab_search_node+0x100/0x1a0
...
load_elf_binary+0x6e8/0x15a0
search_binary_handler+0xe8/0x290
do_execveat_common.isra.14+0x5f4/0x840
call_usermodehelper_exec_async+0x170/0x210
ret_from_kernel_thread+0x5c/0x7c
Fix it by setting abi to PERF_SAMPLE_REGS_ABI_NONE when userspace
pt_regs are not set.
Fixes: ed4a4ef85cf5 ("powerpc/perf: Add support for sampling interrupt register state") Cc: stable@vger.kernel.org # v4.7+ Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com> Acked-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Naveen N. Rao [Tue, 13 Jun 2017 18:42:00 +0000 (00:12 +0530)]
powerpc/64s: Handle data breakpoints in Radix mode
On Power9, trying to use data breakpoints throws the splat shown
below. This is because the check for a data breakpoint in DSISR is in
do_hash_page(), which is not called when in Radix mode.
Move the check to handle_page_fault() so as to catch data breakpoints
in both Hash and Radix MMU modes.
We have to change the check in do_hash_page() against 0xa410 to use
0xa450, so as to include the value of (DSISR_DABRMATCH << 16).
There are two sites that call handle_page_fault() when in Radix, both
already pass DSISR in r4.
Fixes: caca285e5ab4 ("powerpc/mm/radix: Use STD_MMU_64 to properly isolate hash related code") Cc: stable@vger.kernel.org # v4.7+ Reported-by: Shriya R. Kulkarni <shriykul@in.ibm.com> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
[mpe: Fix the fall-through case on hash, we need to reload DSISR] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Naveen N. Rao [Thu, 1 Jun 2017 10:48:17 +0000 (16:18 +0530)]
powerpc/kprobes: Skip livepatch_handler() for jprobes
ftrace_caller() depends on a modified regs->nip to detect if a certain
function has been livepatched. However, with KPROBES_ON_FTRACE, it is
possible for regs->nip to have been modified by the kprobes pre_handler
(jprobes, for instance). In this case, we do not want to invoke the
livepatch_handler so as not to consume the livepatch stack.
To distinguish between the two (kprobes and livepatch), we check if
there is an active kprobe on the current function. If there is, then we
know for sure that it must have modified the NIP as we don't support
livepatching a kprobe'd function. In this case, we simply skip the
livepatch_handler and branch to the new NIP. Otherwise, the
livepatch_handler is invoked.
Fixes: ead514d5fb30 ("powerpc/kprobes: Add support for KPROBES_ON_FTRACE") Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Naveen N. Rao [Thu, 1 Jun 2017 10:48:16 +0000 (16:18 +0530)]
powerpc/ftrace: Pass the correct stack pointer for DYNAMIC_FTRACE_WITH_REGS
For DYNAMIC_FTRACE_WITH_REGS, we should be passing-in the original set
of registers in pt_regs, to capture the state _before_ ftrace_caller.
However, we are instead passing the stack pointer *after* allocating a
stack frame in ftrace_caller. Fix this by saving the proper value of r1
in pt_regs. Also, use SAVE_10GPRS() to simplify the code.
Fixes: 153086644fd1 ("powerpc/ftrace: Add support for -mprofile-kernel ftrace ABI") Cc: stable@vger.kernel.org # v4.6+ Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Naveen N. Rao [Thu, 1 Jun 2017 10:48:15 +0000 (16:18 +0530)]
powerpc/kprobes: Pause function_graph tracing during jprobes handling
This fixes a crash when function_graph and jprobes are used together.
This is essentially commit 237d28db036e ("ftrace/jprobes/x86: Fix
conflict between jprobes and function graph tracing"), but for powerpc.
Jprobes breaks function_graph tracing since the jprobe hook needs to use
jprobe_return(), which never returns back to the hook, but instead to
the original jprobe'd function. The solution is to momentarily pause
function_graph tracing before invoking the jprobe hook and re-enable it
when returning back to the original jprobe'd function.
Fixes: 6794c78243bf ("powerpc64: port of the function graph tracer") Cc: stable@vger.kernel.org # v2.6.30+ Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
powerpc/debug: Add missing warn flag to WARN_ON's non-builtin path
When trapped on WARN_ON(), report_bug() is expected to return
BUG_TRAP_TYPE_WARN so the caller will increment NIP by 4 and continue.
The __builtin_constant_p() path of the PPC's WARN_ON()
calls (indirectly) __WARN_FLAGS() which has BUGFLAG_WARNING set,
however the other branch does not which makes report_bug() report a
bug rather than a warning.
Architecturally we should apply a 0x400 offset for these. Not doing
it will break future HW implementations.
The offset of 0 is supposed to remain for "triggers" though not all
sources support both trigger and store EOI, and in P9 specifically,
some sources will treat 0 as a store EOI. But future chips will not.
So this makes us use the properly architected offset which should work
always.
Fixes: 243e25112d06 ("powerpc/xive: Native exploitation of the XIVE interrupt controller") Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
drivers/watchdog/wdrtas.c uses symbols defined in arch/powerpc/kernel/rtas.c,
which are exported iff CONFIG_PPC_RTAS is selected. Building wdrtas.c without
setting CONFIG_PPC_RTAS throws the following errors:
Nicholas Piggin [Thu, 8 Jun 2017 15:36:09 +0000 (01:36 +1000)]
powerpc/64s: Avoid cpabort in context switch when possible
The ISA v3.0B copy-paste facility only requires cpabort when switching
to a process that has foreign real addresses mapped (direct access to
accelerators), to clear a potential copy buffer filled by a previous
thread. There is no accelerator driver implemented yet, so cpabort can
be removed. It can be be re-added when a driver is implemented.
POWER9 DD1 requires the copy buffer to always be cleared on context
switch, but if accelerators are not in use, then an unpaired copy from
a dummy region is sufficient to clear data out of the copy buffer.
This increases context switch performance by about 5% on POWER9.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Nicholas Piggin [Thu, 8 Jun 2017 15:36:08 +0000 (01:36 +1000)]
powerpc/64: Drop explicit hwsync in context switch
The sync (aka. hwsync, aka. heavyweight sync) in the context switch
code to prevent MMIO access being reordered from the point of view of
a single process if it gets migrated to a different CPU is not
required because there is an hwsync performed earlier in the context
switch path.
Comment this so it's clear enough if anything changes on the scheduler
or the powerpc sides. Remove the hwsync from _switch.
This improves context switch performance by 2-3% on POWER8.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Nicholas Piggin [Thu, 8 Jun 2017 15:36:06 +0000 (01:36 +1000)]
powerpc/64s: Leave interrupts hard enabled in context switch for radix
Commit 4387e9ff25 ("[POWERPC] Fix PMU + soft interrupt disable bug")
hard disabled interrupts over the low level context switch, because
the SLB management can't cope with a PMU interrupt accesing the stack
in that window.
Radix based kernel mapping does not use the SLB so it does not require
interrupts hard disabled here.
This is worth 1-2% in context switch performance on POWER9.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Nicholas Piggin [Thu, 8 Jun 2017 15:35:05 +0000 (01:35 +1000)]
powerpc/64: Avoid restore_math call if possible in syscall exit
The syscall exit code that branches to restore_math is quite heavy on
Book3S, consisting of 2 mtmsr instructions. Threads that don't use both
FP and vector can get caught here if the kernel ever uses FP or vector.
Lazy-FP/vec context switching also trips this case.
So check for lazy FP and vector before switching RI for restore_math.
Move most of this case out of line.
For threads that do want to restore math registers, the MSR switches are
still suboptimal. Future direction may be to use a soft-RI bit to avoid
MSR switches in kernel (similar to soft-EE), but for now at least the
no-restore
POWER9 context switch rate increases by about 5% due to sched_yield(2)
return performance. I haven't constructed a test to measure the syscall
cost.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Nicholas Piggin [Thu, 8 Jun 2017 15:35:04 +0000 (01:35 +1000)]
powerpc/64s: Optimize hypercall/syscall entry
After bc3551257a ("powerpc/64: Allow for relocation-on interrupts from
guest to host"), a getppid() system call goes from 307 cycles to 358
cycles (+17%) on POWER8. This is due significantly to the scratch SPR
used by the hypercall check.
It turns out there are a some volatile registers common to both system
call and hypercall (in particular, r12, cr0, ctr), which can be used to
avoid the SPR and some other overheads. This brings getppid to 320 cycles
(+4%).
Testing hcall entry performance by running "sc 1" in guest userspace
before this patch is 854 cycles, afterwards is 826. Also a small win
there.
POWER9 syscall is improved by about the same amount, hcall not tested.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
powerpc/mm/radix: Only add X for pages overlapping kernel text
Currently we map the whole linear mapping with PAGE_KERNEL_X. Instead we
should check if the page overlaps the kernel text and only then add
PAGE_KERNEL_X.
Note that we still use 1G pages if they're available, so this will
typically still result in a 1G executable page at KERNELBASE. So this fix is
primarily useful for catching stray branches to high linear mapping addresses.
Without this patch, we can execute at 1G in xmon using: