linux-toradex.git/arch/powerpc/include, branch v4.4.129

powerpc/powernv: define a standard delay for OPAL_BUSY type retry loops

2018-04-24T07:32:06+00:00

commit 34dd25de9fe3f60bfdb31b473bf04b28262d0896 upstream.

This is the start of an effort to tidy up and standardise all the
delays. Existing loops have a range of delay/sleep periods from 1ms
to 20ms, and some have no delay. They all loop forever except rtc,
which times out after 10 retries, and that uses 10ms delays. So use
10ms as our standard delay. The OPAL maintainer agrees 10ms is a
reasonable starting point.

The idea is to use the same recipe everywhere, once this is proven to
work then it will be documented as an OPAL API standard. Then both
firmware and OS can agree, and if a particular call needs something
else, then that can be documented with reasoning.

This is not the end-all of this effort, it's just a relatively easy
change that fixes some existing high latency delays. There should be
provision for standardising timeouts and/or interruptible loops where
possible, so non-fatal firmware errors don't cause hangs.

Signed-off-by: Nicholas Piggin 
Signed-off-by: Michael Ellerman 
Cc: Nathan Chancellor 
Cc: Guenter Roeck 
Signed-off-by: Greg Kroah-Hartman

powerpc/64: Fix smp_wmb barrier definition use use lwsync consistently

2018-04-24T07:32:06+00:00

commit 0bfdf598900fd62869659f360d3387ed80eb71cf upstream.

asm/barrier.h is not always included after asm/synch.h, which meant
it was missing __SUBARCH_HAS_LWSYNC, so in some files smp_wmb() would
be eieio when it should be lwsync. kernel/time/hrtimer.c is one case.

__SUBARCH_HAS_LWSYNC is only used in one place, so just fold it in
to where it's used. Previously with my small simulator config, 377
instances of eieio in the tree. After this patch there are 55.

Fixes: 46d075be585e ("powerpc: Optimise smp_wmb")
Cc: stable@vger.kernel.org # v2.6.29+
Signed-off-by: Nicholas Piggin 
Signed-off-by: Michael Ellerman 
Signed-off-by: Greg Kroah-Hartman

powerpc/mm: Fix virt_addr_valid() etc. on 64-bit hash

2018-04-13T17:50:08+00:00

[ Upstream commit e41e53cd4fe331d0d1f06f8e4ed7e2cc63ee2c34 ]

virt_addr_valid() is supposed to tell you if it's OK to call virt_to_page() on
an address. What this means in practice is that it should only return true for
addresses in the linear mapping which are backed by a valid PFN.

We are failing to properly check that the address is in the linear mapping,
because virt_to_pfn() will return a valid looking PFN for more or less any
address. That bug is actually caused by __pa(), used in virt_to_pfn().

eg: __pa(0xc000000000010000) = 0x10000  # Good
    __pa(0xd000000000010000) = 0x10000  # Bad!
    __pa(0x0000000000010000) = 0x10000  # Bad!

This started happening after commit bdbc29c19b26 ("powerpc: Work around gcc
miscompilation of __pa() on 64-bit") (Aug 2013), where we changed the definition
of __pa() to work around a GCC bug. Prior to that we subtracted PAGE_OFFSET from
the value passed to __pa(), meaning __pa() of a 0xd or 0x0 address would give
you something bogus back.

Until we can verify if that GCC bug is no longer an issue, or come up with
another solution, this commit does the minimal fix to make virt_addr_valid()
work, by explicitly checking that the address is in the linear mapping region.

Fixes: bdbc29c19b26 ("powerpc: Work around gcc miscompilation of __pa() on 64-bit")
Signed-off-by: Michael Ellerman 
Reviewed-by: Paul Mackerras 
Reviewed-by: Balbir Singh 
Tested-by: Breno Leitao 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

powerpc/pseries: include linux/types.h in asm/hvcall.h

2018-02-16T19:09:39+00:00

commit 1b689a95ce7427075f9ac9fb4aea1af530742b7f upstream.

Commit 6e032b350cd1 ("powerpc/powernv: Check device-tree for RFI flush
settings") uses u64 in asm/hvcall.h without including linux/types.h

This breaks hvcall.h users that do not include the header themselves.

Fixes: 6e032b350cd1 ("powerpc/powernv: Check device-tree for RFI flush settings")
Signed-off-by: Michal Suchanek 
Signed-off-by: Michael Ellerman 
Signed-off-by: Greg Kroah-Hartman

powerpc/64s: Add support for RFI flush of L1-D cache

2018-02-16T19:09:35+00:00

commit aa8a5e0062ac940f7659394f4817c948dc8c0667 upstream.

On some CPUs we can prevent the Meltdown vulnerability by flushing the
L1-D cache on exit from kernel to user mode, and from hypervisor to
guest.

This is known to be the case on at least Power7, Power8 and Power9. At
this time we do not know the status of the vulnerability on other CPUs
such as the 970 (Apple G5), pasemi CPUs (AmigaOne X1000) or Freescale
CPUs. As more information comes to light we can enable this, or other
mechanisms on those CPUs.

The vulnerability occurs when the load of an architecturally
inaccessible memory region (eg. userspace load of kernel memory) is
speculatively executed to the point where its result can influence the
address of a subsequent speculatively executed load.

In order for that to happen, the first load must hit in the L1,
because before the load is sent to the L2 the permission check is
performed. Therefore if no kernel addresses hit in the L1 the
vulnerability can not occur. We can ensure that is the case by
flushing the L1 whenever we return to userspace. Similarly for
hypervisor vs guest.

In order to flush the L1-D cache on exit, we add a section of nops at
each (h)rfi location that returns to a lower privileged context, and
patch that with some sequence. Newer firmwares are able to advertise
to us that there is a special nop instruction that flushes the L1-D.
If we do not see that advertised, we fall back to doing a displacement
flush in software.

For guest kernels we support migration between some CPU versions, and
different CPUs may use different flush instructions. So that we are
prepared to migrate to a machine with a different flush instruction
activated, we may have to patch more than one flush instruction at
boot if the hypervisor tells us to.

In the end this patch is mostly the work of Nicholas Piggin and
Michael Ellerman. However a cast of thousands contributed to analysis
of the issue, earlier versions of the patch, back ports testing etc.
Many thanks to all of them.

Tested-by: Jon Masters 
Signed-off-by: Nicholas Piggin 
Signed-off-by: Michael Ellerman 
[Balbir - back ported to stable with changes]
Signed-off-by: Balbir Singh 
Signed-off-by: Greg Kroah-Hartman

powerpc/64s: Simple RFI macro conversions

2018-02-16T19:09:34+00:00

commit 222f20f140623ef6033491d0103ee0875fe87d35 upstream.

This commit does simple conversions of rfi/rfid to the new macros that
include the expected destination context. By simple we mean cases
where there is a single well known destination context, and it's
simply a matter of substituting the instruction for the appropriate
macro.

Signed-off-by: Nicholas Piggin 
Signed-off-by: Michael Ellerman 
[Balbir fixed issues with backporting to stable]
Signed-off-by: Balbir Singh 
Signed-off-by: Greg Kroah-Hartman

powerpc/64: Add macros for annotating the destination of rfid/hrfid

2018-02-16T19:09:34+00:00

commit 50e51c13b3822d14ff6df4279423e4b7b2269bc3 upstream.

The rfid/hrfid ((Hypervisor) Return From Interrupt) instruction is
used for switching from the kernel to userspace, and from the
hypervisor to the guest kernel. However it can and is also used for
other transitions, eg. from real mode kernel code to virtual mode
kernel code, and it's not always clear from the code what the
destination context is.

To make it clearer when reading the code, add macros which encode the
expected destination context.

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

powerpc/pseries: Add H_GET_CPU_CHARACTERISTICS flags & wrapper

2018-02-16T19:09:34+00:00

commit 191eccb1580939fb0d47deb405b82a85b0379070 upstream.

A new hypervisor call has been defined to communicate various
characteristics of the CPU to guests. Add definitions for the hcall
number, flags and a wrapper function.

Signed-off-by: Michael Neuling 
Signed-off-by: Michael Ellerman 
[Balbir fixed conflicts in backport]
Signed-off-by: Balbir Singh 
Signed-off-by: Greg Kroah-Hartman

powerpc/64: Fix flush_(d|i)cache_range() called from modules

2018-02-16T19:09:34+00:00

commit 8f5f525d5b83f7d76a6baf9c4e94d4bf312ea7f6 upstream.

When the kernel is compiled to use 64bit ABIv2 the _GLOBAL() macro does
not include a global entry point. A function's global entry point is
used when the function is called from a different TOC context and in the
kernel this typically means a call from a module into the vmlinux (or
vice-versa).

There are a few exported asm functions declared with _GLOBAL() and
calling them from a module will likely crash the kernel since any TOC
relative load will yield garbage.

flush_icache_range() and flush_dcache_range() are both exported to
modules, and use the TOC, so must use _GLOBAL_TOC().

Fixes: 721aeaa9fdf3 ("powerpc: Build little endian ppc64 kernel with ABIv2")
Signed-off-by: Oliver O'Halloran 
Signed-off-by: Michael Ellerman 
Signed-off-by: Greg Kroah-Hartman

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

2017-08-07T02:19:40+00:00

This reverts commit 8c92870bdbf20b5fa5150a2c8bf53ab498516b24 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