Implement the barrier_nospec as a isync;sync instruction sequence.
The implementation uses the infrastructure built for BOOK3S 64.
Signed-off-by: Diana Craciun <diana.craciun@nxp.com>
[mpe: Split out of larger patch]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

In a subsequent patch we will enable building security.c for Book3E.
However the NXP platforms are not vulnerable to Meltdown, so make the
Meltdown vulnerability reporting PPC_BOOK3S_64 specific.
Signed-off-by: Diana Craciun <diana.craciun@nxp.com>
[mpe: Split out of larger patch]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Currently we require platform code to call setup_barrier_nospec(). But
if we add an empty definition for the !CONFIG_PPC_BARRIER_NOSPEC case
then we can call it in setup_arch().
Signed-off-by: Diana Craciun <diana.craciun@nxp.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Add a config symbol to encode which platforms support the
barrier_nospec speculation barrier. Currently this is just Book3S 64
but we will add Book3E in a future patch.
Signed-off-by: Diana Craciun <diana.craciun@nxp.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

NXP Book3E platforms are not vulnerable to speculative store
bypass, so make the mitigations PPC_BOOK3S_64 specific.
Signed-off-by: Diana Craciun <diana.craciun@nxp.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

The speculation barrier can be disabled from the command line
with the parameter: "nospectre_v1".
Signed-off-by: Diana Craciun <diana.craciun@nxp.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

We only need to use __MASKABLE_EXCEPTION in one of the four cases for
hardware interrupt, so use the helper macros in the other cases.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

We pass the "loc" (location) parameter to MASKABLE_EXCEPTION and
friends, but it's not used, so drop it.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

_MASKABLE_RELON_EXCEPTION_PSERIES() does nothing useful, update all
callers to use __MASKABLE_RELON_EXCEPTION_PSERIES() directly.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

_MASKABLE_EXCEPTION_PSERIES() does nothing useful, update all callers
to use __MASKABLE_EXCEPTION_PSERIES() directly.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

To just EXCEPTION_RELON_PROLOG().
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

The EXCEPTION_RELON_PROLOG_PSERIES_1() macro does the same job as
EXCEPTION_PROLOG_2 (which we just recently created), except for
"RELON" (relocation on) exceptions.

So rename it as such.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

As with the other patches in this series, we are removing the
"PSERIES" from the name as it's no longer meaningful.

In this case it's not simply a case of removing the "PSERIES" as that
would result in a clash with the existing EXCEPTION_PROLOG_1.

Instead we name this one EXCEPTION_PROLOG_2, as it's usually used in
sequence after 0 and 1.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

The "PSERIES" in STD_EXCEPTION_PSERIES is to differentiate the macros
from the legacy iSeries versions, which are called
STD_EXCEPTION_ISERIES. It is not anything to do with pseries vs
powernv or powermac etc.

We removed the legacy iSeries code in 2012, in commit 8ee3e0d6x
("powerpc: Remove the main legacy iSerie platform code").

So remove "PSERIES" from the macros.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

EXCEPTION_RELON_PROLOG_PSERIES() only has two users,
STD_RELON_EXCEPTION_PSERIES() and STD_RELON_EXCEPTION_HV() both of
which "call" SET_SCRATCH0(), so just move SET_SCRATCH0() into
EXCEPTION_RELON_PROLOG_PSERIES().
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

EXCEPTION_PROLOG_PSERIES() only has two users, STD_EXCEPTION_PSERIES()
and STD_EXCEPTION_HV() both of which "call" SET_SCRATCH0(), so just
move SET_SCRATCH0() into EXCEPTION_PROLOG_PSERIES().
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Pasemi arch code finds the root of the PCI-e bus by searching the
device-tree for a node called 'pxp'. But the root bus has a compatible
property of 'pasemi,rootbus' so search for that instead.
Signed-off-by: Darren Stevens <darren@stevens-zone.net>
Acked-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

This patch adds a test for testing the new assembly strlen() for PPC32
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
[mpe: Fix 64-bit build]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

The generic implementation of strlen() reads strings byte per byte.

This patch implements strlen() in assembly based on a read of entire
words, in the same spirit as what some other arches and glibc do.

On a 8xx the time spent in strlen is reduced by 3/4 for long strings.

strlen() selftest on an 8xx provides the following values:

Before the patch (ie with the generic strlen() in lib/string.c):

  len 256 : time = 1.195055
  len 016 : time = 0.083745
  len 008 : time = 0.046828
  len 004 : time = 0.028390

After the patch:

  len 256 : time = 0.272185 ==> 78% improvment
  len 016 : time = 0.040632 ==> 51% improvment
  len 008 : time = 0.033060 ==> 29% improvment
  len 004 : time = 0.029149 ==> 2% degradation

On a 832x:

Before the patch:

  len 256 : time = 0.236125
  len 016 : time = 0.018136
  len 008 : time = 0.011000
  len 004 : time = 0.007229

After the patch:

  len 256 : time = 0.094950 ==> 60% improvment
  len 016 : time = 0.013357 ==> 26% improvment
  len 008 : time = 0.010586 ==> 4% improvment
  len 004 : time = 0.008784
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

This patch adds a test for strlen()

string.c contains a copy of strlen() from lib/string.c

The test first tests the correctness of strlen() by comparing
the result with libc strlen(). It tests all cases of alignment.

It them tests the duration of an aligned strlen() on a 4 bytes string,
on a 16 bytes string and on a 256 bytes string.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
[mpe: Drop change log from copy of string.c]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

This patch renames memcmp test to memcmp_64 and adds a memcmp_32 test
for testing the 32 bits version of memcmp()
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
[mpe: Fix 64-bit build by adding build_32bit test]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

rtas_log_buf is a buffer to hold RTAS event data that are communicated
to kernel by hypervisor. This buffer is then used to pass RTAS event
data to user through proc fs. This buffer is allocated from
vmalloc (non-linear mapping) area.

On Machine check interrupt, register r3 points to RTAS extended event
log passed by hypervisor that contains the MCE event. The pseries
machine check handler then logs this error into rtas_log_buf. The
rtas_log_buf is a vmalloc-ed (non-linear) buffer we end up taking up a
page fault (vector 0x300) while accessing it. Since machine check
interrupt handler runs in NMI context we can not afford to take any
page fault. Page faults are not honored in NMI context and causes
kernel panic. Apart from that, as Nick pointed out,
pSeries_log_error() also takes a spin_lock while logging error which
is not safe in NMI context. It may endup in deadlock if we get another
MCE before releasing the lock. Fix this by deferring the logging of
rtas error to irq work queue.

Current implementation uses two different buffers to hold rtas error
log depending on whether extended log is provided or not. This makes
bit difficult to identify which buffer has valid data that needs to
logged later in irq work. Simplify this using single buffer, one per
paca, and copy rtas log to it irrespective of whether extended log is
provided or not. Allocate this buffer below RMA region so that it can
be accessed in real mode mce handler.

Fixes: b96672dd ("powerpc: Machine check interrupt is a non-maskable interrupt")
Cc: stable@vger.kernel.org # v4.14+
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

The global mce data buffer that used to copy rtas error log is of 2048
(RTAS_ERROR_LOG_MAX) bytes in size. Before the copy we read
extended_log_length from rtas error log header, then use max of
extended_log_length and RTAS_ERROR_LOG_MAX as a size of data to be copied.
Ideally the platform (phyp) will never send extended error log with
size > 2048. But if that happens, then we have a risk of buffer overrun
and corruption. Fix this by using min_t instead.

Fixes: d368514c ("powerpc: Fix corruption when grabbing FWNMI data")
Reported-by: Michal Suchanek <msuchanek@suse.com>
Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

It's identical to xive_teardown_cpu() so just use the latter
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Those overly verbose statement in the setup of the pool VP
aren't particularly useful (esp. considering we don't actually
use the pool, we configure it bcs HW requires it only). So
remove them which improves the code readability.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

The kernel page table caches are tied to init_mm, so there is no
more need for them after userspace is finished.

destroy_context() gets called when we drop the last reference for an
mm, which can be much later than the task exit due to other lazy mm
references to it. We can free the page table cache pages on task exit
because they only cache the userspace page tables and kernel threads
should not access user space addresses.

The mapping for kernel threads itself is maintained in init_mm and
page table cache for that is attached to init_mm.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
[mpe: Merge change log additions from Aneesh]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

When the mm is being torn down there will be a full PID flush so
there is no need to flush the TLB on page size changes.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Some of these long running tests can time out on heavily loaded
systems, give them longer to run.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

These tests are currently failing on (some) big endian systems. Until
we can fix that, skip them unless we're on ppc64le.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Some of our selftests have only been tested on ppc64le and crash or
behave weirdly on ppc64/ppc32. So add a helper for checking the UTS
machine.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

This makes it easy to run checkpatch with settings that I like.

Usage is eg:

  $ ./arch/powerpc/tools/checkpatch.sh -g origin/master..

To check all commits since origin/master.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Russell Currey <ruscur@russell.cc>

We recently added a warning in arch_local_irq_restore() to check that
the soft masking state matches reality.

Unfortunately it trips in a few places, which are not entirely trivial
to fix. The key problem is if we're doing function_graph tracing of
restore_math(), the warning pops and then seems to recurse. It's not
entirely clear because the system continuously oopses on all CPUs,
with the output interleaved and unreadable.

It's also been observed on a G5 coming out of idle.

Until we can fix those cases disable the warning for now.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

We've encountered a performance issue when multiple processors stress
{get,put}_mmio_atsd_reg(). These functions contend for
mmio_atsd_usage, an unsigned long used as a bitmask.

The accesses to mmio_atsd_usage are done using test_and_set_bit_lock()
and clear_bit_unlock(). As implemented, both of these will require
a (successful) stwcx to that same cache line.

What we end up with is thread A, attempting to unlock, being slowed by
other threads repeatedly attempting to lock. A's stwcx instructions
fail and retry because the memory reservation is lost every time a
different thread beats it to the punch.

There may be a long-term way to fix this at a larger scale, but for
now resolve the immediate problem by gating our call to
test_and_set_bit_lock() with one to test_bit(), which is obviously
implemented without using a store.

Fixes: 1ab66d1f ("powerpc/powernv: Introduce address translation services for Nvlink2")
Signed-off-by: Reza Arbab <arbab@linux.ibm.com>
Acked-by: Alistair Popple <alistair@popple.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

kernel/dma/Kconfig already defines NEED_DMA_MAP_STATE, just select it
from CONFIG_PPC using the same condition as an if guard.
Signed-off-by: Christoph Hellwig <hch@lst.de>
[mpe: Move it under PPC]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>