linux.git/arch/powerpc/include, branch v3.18.64

arch/powerpc: provide zero_bytemask() for big-endian

2017-08-11T16:30:13+00:00

commit 7a5692e6e533fd379081ab06fb58f3f5ee4d80bc upstream.

For some reason, only the little-endian flavor of
powerpc provided the zero_bytemask() implementation.

Reported-by: Michal Sojka 
Acked-by: Michael Ellerman 
Signed-off-by: Chris Metcalf 
Signed-off-by: Greg Kroah-Hartman

Make asm/word-at-a-time.h available on all architectures

2017-08-11T16:30:13+00:00

commit a6e2f029ae34f41adb6ae3812c32c5d326e1abd2 upstream.

Added the x86 implementation of word-at-a-time to the
generic version, which previously only supported big-endian.

Omitted the x86-specific load_unaligned_zeropad(), which in
any case is also not present for the existing BE-only
implementation of a word-at-a-time, and is only used under
CONFIG_DCACHE_WORD_ACCESS.

Added as a "generic-y" to the Kbuilds of all architectures
that didn't previously have it.

Signed-off-by: Chris Metcalf 
Signed-off-by: Greg Kroah-Hartman

Revert "powerpc/numa: Fix percpu allocations to be NUMA aware"

2017-08-11T16:30:08+00:00

This reverts commit 138bb14846a5856747694ae9ef565c9eb4533a1e which is
commit ba4a648f12f4cd0a8003dd229b6ca8a53348ee4b upstream.

Michal Hocko writes:

JFYI. We have encountered a regression after applying this patch on a
large ppc machine. While the patch is the right thing to do it doesn't
work well with the current vmalloc area size on ppc and large machines
where NUMA nodes are very far from each other. Just for the reference
the boot fails on such a machine with bunch of warning preceeding it.
See http://lkml.kernel.org/r/20170724134240.GL25221@dhcp22.suse.cz

It seems the right thing to do is to enlarge the vmalloc space on ppc
but this is not the case in the upstream kernel yet AFAIK. It is also
questionable whether that is a stable material but I will decision on
you here.

We have reverted this patch from our 4.4 based kernel.

Newer kernels do not have enlarged vmalloc space yet AFAIK so they won't
work properly eiter. This bug is quite rare though because you need a
specific HW configuration to trigger the issue - namely NUMA nodes have
to be far away from each other in the physical memory space.

Cc: Michal Hocko 
Cc: Michael Ellerman 
Cc: Nicholas Piggin 
Signed-off-by: Greg Kroah-Hartman

powerpc/asm: Mark cr0 as clobbered in mftb()

2017-07-27T22:03:25+00:00

commit 2400fd822f467cb4c886c879d8ad99feac9cf319 upstream.

The workaround for the CELL timebase bug does not correctly mark cr0 as
being clobbered. This means GCC doesn't know that the asm block changes cr0 and
might leave the result of an unrelated comparison in cr0 across the block, which
we then trash, leading to basically random behaviour.

Fixes: 859deea949c3 ("[POWERPC] Cell timebase bug workaround")
Signed-off-by: Oliver O'Halloran 
[mpe: Tweak change log and flag for stable]
Signed-off-by: Michael Ellerman 
Signed-off-by: Greg Kroah-Hartman

powerpc/64: Fix atomic64_inc_not_zero() to return an int

2017-07-27T22:03:25+00:00

commit 01e6a61aceb82e13bec29502a8eb70d9574f97ad upstream.

Although it's not documented anywhere, there is an expectation that
atomic64_inc_not_zero() returns a result which fits in an int. This is
the behaviour implemented on all arches except powerpc.

This has caused at least one bug in practice, in the percpu-refcount
code, where the long result from our atomic64_inc_not_zero() was
truncated to an int leading to lost references and stuck systems. That
was worked around in that code in commit 966d2b04e070 ("percpu-refcount:
fix reference leak during percpu-atomic transition").

To the best of my grepping abilities there are no other callers
in-tree which truncate the value, but we should fix it anyway. Because
the breakage is subtle and potentially very harmful I'm also tagging
it for stable.

Code generation is largely unaffected because in most cases the
callers are just using the result for a test anyway. In particular the
case of fget() that was mentioned in commit a6cf7ed5119f
("powerpc/atomic: Implement atomic*_inc_not_zero") generates exactly
the same code.

Fixes: a6cf7ed5119f ("powerpc/atomic: Implement atomic*_inc_not_zero")
Noticed-by: Linus Torvalds 
Signed-off-by: Michael Ellerman 
Signed-off-by: Greg Kroah-Hartman

powerpc/numa: Fix percpu allocations to be NUMA aware

2017-06-14T10:54:19+00:00

commit ba4a648f12f4cd0a8003dd229b6ca8a53348ee4b upstream.

In commit 8c272261194d ("powerpc/numa: Enable USE_PERCPU_NUMA_NODE_ID"), we
switched to the generic implementation of cpu_to_node(), which uses a percpu
variable to hold the NUMA node for each CPU.

Unfortunately we neglected to notice that we use cpu_to_node() in the allocation
of our percpu areas, leading to a chicken and egg problem. In practice what
happens is when we are setting up the percpu areas, cpu_to_node() reports that
all CPUs are on node 0, so we allocate all percpu areas on node 0.

This is visible in the dmesg output, as all pcpu allocs being in group 0:

  pcpu-alloc: [0] 00 01 02 03 [0] 04 05 06 07
  pcpu-alloc: [0] 08 09 10 11 [0] 12 13 14 15
  pcpu-alloc: [0] 16 17 18 19 [0] 20 21 22 23
  pcpu-alloc: [0] 24 25 26 27 [0] 28 29 30 31
  pcpu-alloc: [0] 32 33 34 35 [0] 36 37 38 39
  pcpu-alloc: [0] 40 41 42 43 [0] 44 45 46 47

To fix it we need an early_cpu_to_node() which can run prior to percpu being
setup. We already have the numa_cpu_lookup_table we can use, so just plumb it
in. With the patch dmesg output shows two groups, 0 and 1:

  pcpu-alloc: [0] 00 01 02 03 [0] 04 05 06 07
  pcpu-alloc: [0] 08 09 10 11 [0] 12 13 14 15
  pcpu-alloc: [0] 16 17 18 19 [0] 20 21 22 23
  pcpu-alloc: [1] 24 25 26 27 [1] 28 29 30 31
  pcpu-alloc: [1] 32 33 34 35 [1] 36 37 38 39
  pcpu-alloc: [1] 40 41 42 43 [1] 44 45 46 47

We can also check the data_offset in the paca of various CPUs, with the fix we
see:

  CPU 0:  data_offset = 0x0ffe8b0000
  CPU 24: data_offset = 0x1ffe5b0000

And we can see from dmesg that CPU 24 has an allocation on node 1:

  node   0: [mem 0x0000000000000000-0x0000000fffffffff]
  node   1: [mem 0x0000001000000000-0x0000001fffffffff]

Fixes: 8c272261194d ("powerpc/numa: Enable USE_PERCPU_NUMA_NODE_ID")
Signed-off-by: Michael Ellerman 
Reviewed-by: Nicholas Piggin 
Signed-off-by: Michael Ellerman 
Signed-off-by: Greg Kroah-Hartman

KVM: PPC: Book3S HV: Save/restore XER in checkpointed register state

2017-01-15T14:49:49+00:00

[ Upstream commit 0d808df06a44200f52262b6eb72bcb6042f5a7c5 ]

When switching from/to a guest that has a transaction in progress,
we need to save/restore the checkpointed register state.  Although
XER is part of the CPU state that gets checkpointed, the code that
does this saving and restoring doesn't save/restore XER.

This fixes it by saving and restoring the XER.  To allow userspace
to read/write the checkpointed XER value, we also add a new ONE_REG
specifier.

The visible effect of this bug is that the guest may see its XER
value being corrupted when it uses transactions.

Fixes: e4e38121507a ("KVM: PPC: Book3S HV: Add transactional memory support")
Fixes: 0a8eccefcb34 ("KVM: PPC: Book3S HV: Add missing code for transaction reclaim on guest exit")
Cc: stable@vger.kernel.org # v3.15+
Signed-off-by: Paul Mackerras 
Reviewed-by: Thomas Huth 
Signed-off-by: Paul Mackerras 
Signed-off-by: Sasha Levin

ppc32: fix copy_from_user()

2016-10-06T02:40:20+00:00

[ Upstream commit 224264657b8b228f949b42346e09ed8c90136a8e ]

should clear on access_ok() failures.  Also remove the useless
range truncation logics.

Cc: stable@vger.kernel.org
Signed-off-by: Al Viro 
Signed-off-by: Sasha Levin

powerpc: Use privileged SPR number for MMCR2

2016-06-20T03:47:40+00:00

[ Upstream commit 8dd75ccb571f3c92c48014b3dabd3d51a115ab41 ]

We are already using the privileged versions of MMCR0, MMCR1
and MMCRA in the kernel, so for MMCR2, we should better use
the privileged versions, too, to be consistent.

Fixes: 240686c13687 ("powerpc: Initialise PMU related regs on Power8")
Cc: stable@vger.kernel.org # v3.10+
Suggested-by: Paul Mackerras 
Signed-off-by: Thomas Huth 
Acked-by: Paul Mackerras 
Signed-off-by: Michael Ellerman 
Signed-off-by: Sasha Levin

powerpc: Fix definition of SIAR and SDAR registers

2016-06-20T03:47:40+00:00

[ Upstream commit d23fac2b27d94aeb7b65536a50d32bfdc21fe01e ]

The SIAR and SDAR registers are available twice, one time as SPRs
780 / 781 (unprivileged, but read-only), and one time as the SPRs
796 / 797 (privileged, but read and write). The Linux kernel code
currently uses the unprivileged  SPRs - while this is OK for reading,
writing to that register of course does not work.
Since the KVM code tries to write to this register, too (see the mtspr
in book3s_hv_rmhandlers.S), the contents of this register sometimes get
lost for the guests, e.g. during migration of a VM.
To fix this issue, simply switch to the privileged SPR numbers instead.

Cc: stable@vger.kernel.org
Signed-off-by: Thomas Huth 
Acked-by: Paul Mackerras 
Signed-off-by: Michael Ellerman 
Signed-off-by: Sasha Levin