linux-stable.git/arch/powerpc/include, branch v4.4.8

powerpc/powernv: Fix OPAL_CONSOLE_FLUSH prototype and usages

2016-03-16T15:43:01+00:00

commit c88c5d43732a0356f99e5e4d1ad62ab1ea516b81 upstream.

The recently added OPAL API call, OPAL_CONSOLE_FLUSH, originally took no
parameters and returned nothing.  The call was updated to accept the
terminal number to flush, and returned various values depending on the
state of the output buffer.

The prototype has been updated and its usage in the OPAL kmsg dumper has
been modified to support its new behaviour as an incremental flush.

Signed-off-by: Russell Currey 
Signed-off-by: Michael Ellerman 
Signed-off-by: Greg Kroah-Hartman

powerpc/powernv: Add a kmsg_dumper that flushes console output on panic

2016-03-16T15:43:01+00:00

commit affddff69c55eb68969448f35f59054a370bc7c1 upstream.

On BMC machines, console output is controlled by the OPAL firmware and is
only flushed when its pollers are called.  When the kernel is in a panic
state, it no longer calls these pollers and thus console output does not
completely flush, causing some output from the panic to be lost.

Output is only actually lost when the kernel is configured to not power off
or reboot after panic (i.e. CONFIG_PANIC_TIMEOUT is set to 0) since OPAL
flushes the console buffer as part of its power down routines.  Before this
patch, however, only partial output would be printed during the timeout wait.

This patch adds a new kmsg_dumper which gets called at panic time to ensure
panic output is not lost.  It accomplishes this by calling OPAL_CONSOLE_FLUSH
in the OPAL API, and if that is not available, the pollers are called enough
times to (hopefully) completely flush the buffer.

The flushing mechanism will only affect output printed at and before the
kmsg_dump call in kernel/panic.c:panic().  As such, the "end Kernel panic"
message may still be truncated as follows:

>Call Trace:
>[c000000f1f603b00] [c0000000008e9458] dump_stack+0x90/0xbc (unreliable)
>[c000000f1f603b30] [c0000000008e7e78] panic+0xf8/0x2c4
>[c000000f1f603bc0] [c000000000be4860] mount_block_root+0x288/0x33c
>[c000000f1f603c80] [c000000000be4d14] prepare_namespace+0x1f4/0x254
>[c000000f1f603d00] [c000000000be43e8] kernel_init_freeable+0x318/0x350
>[c000000f1f603dc0] [c00000000000bd74] kernel_init+0x24/0x130
>[c000000f1f603e30] [c0000000000095b0] ret_from_kernel_thread+0x5c/0xac
>---[ end Kernel panic - not

This functionality is implemented as a kmsg_dumper as it seems to be the
most sensible way to introduce platform-specific functionality to the
panic function.

Signed-off-by: Russell Currey 
Reviewed-by: Andrew Donnellan 
Signed-off-by: Michael Ellerman 
Signed-off-by: Greg Kroah-Hartman

powerpc/eeh: Fix stale cached primary bus

2016-02-25T20:01:18+00:00

commit 05ba75f848647135f063199dc0e9f40fee769724 upstream.

When PE is created, its primary bus is cached to pe->bus. At later
point, the cached primary bus is returned from eeh_pe_bus_get().
However, we could get stale cached primary bus and run into kernel
crash in one case: full hotplug as part of fenced PHB error recovery
releases all PCI busses under the PHB at unplugging time and recreate
them at plugging time. pe->bus is still dereferencing the PCI bus
that was released.

This adds another PE flag (EEH_PE_PRI_BUS) to represent the validity
of pe->bus. pe->bus is updated when its first child EEH device is
online and the flag is set. Before unplugging in full hotplug for
error recovery, the flag is cleared.

Fixes: 8cdb2833 ("powerpc/eeh: Trace PCI bus from PE")
Reported-by: Andrew Donnellan 
Reported-by: Pradipta Ghosh 
Signed-off-by: Gavin Shan 
Tested-by: Andrew Donnellan 
Signed-off-by: Michael Ellerman 
Signed-off-by: Greg Kroah-Hartman

powerpc/module: Handle R_PPC64_ENTRY relocations

2016-01-31T19:29:03+00:00

commit a61674bdfc7c2bf909c4010699607b62b69b7bec upstream.

GCC 6 will include changes to generated code with -mcmodel=large,
which is used to build kernel modules on powerpc64le.  This was
necessary because the large model is supposed to allow arbitrary
sizes and locations of the code and data sections, but the ELFv2
global entry point prolog still made the unconditional assumption
that the TOC associated with any particular function can be found
within 2 GB of the function entry point:

func:
	addis r2,r12,(.TOC.-func)@ha
	addi  r2,r2,(.TOC.-func)@l
	.localentry func, .-func

To remove this assumption, GCC will now generate instead this global
entry point prolog sequence when using -mcmodel=large:

	.quad .TOC.-func
func:
	.reloc ., R_PPC64_ENTRY
	ld    r2, -8(r12)
	add   r2, r2, r12
	.localentry func, .-func

The new .reloc triggers an optimization in the linker that will
replace this new prolog with the original code (see above) if the
linker determines that the distance between .TOC. and func is in
range after all.

Since this new relocation is now present in module object files,
the kernel module loader is required to handle them too.  This
patch adds support for the new relocation and implements the
same optimization done by the GNU linker.

Signed-off-by: Ulrich Weigand 
Signed-off-by: Michael Ellerman 
Signed-off-by: Greg Kroah-Hartman

powerpc: Make {cmp}xchg* and their atomic_ versions fully ordered

2016-01-31T19:29:03+00:00

commit 81d7a3294de7e9828310bbf986a67246b13fa01e upstream.

According to memory-barriers.txt, xchg*, cmpxchg* and their atomic_
versions all need to be fully ordered, however they are now just
RELEASE+ACQUIRE, which are not fully ordered.

So also replace PPC_RELEASE_BARRIER and PPC_ACQUIRE_BARRIER with
PPC_ATOMIC_ENTRY_BARRIER and PPC_ATOMIC_EXIT_BARRIER in
__{cmp,}xchg_{u32,u64} respectively to guarantee fully ordered semantics
of atomic{,64}_{cmp,}xchg() and {cmp,}xchg(), as a complement of commit
b97021f85517 ("powerpc: Fix atomic_xxx_return barrier semantics")

This patch depends on patch "powerpc: Make value-returning atomics fully
ordered" for PPC_ATOMIC_ENTRY_BARRIER definition.

Signed-off-by: Boqun Feng 
Reviewed-by: Paul E. McKenney 
Acked-by: Peter Zijlstra (Intel) 
Signed-off-by: Michael Ellerman 
Signed-off-by: Greg Kroah-Hartman

powerpc: Make value-returning atomics fully ordered

2016-01-31T19:29:03+00:00

commit 49e9cf3f0c04bf76ffa59242254110309554861d upstream.

According to memory-barriers.txt:

> Any atomic operation that modifies some state in memory and returns
> information about the state (old or new) implies an SMP-conditional
> general memory barrier (smp_mb()) on each side of the actual
> operation ...

Which mean these operations should be fully ordered. However on PPC,
PPC_ATOMIC_ENTRY_BARRIER is the barrier before the actual operation,
which is currently "lwsync" if SMP=y. The leading "lwsync" can not
guarantee fully ordered atomics, according to Paul Mckenney:

https://lkml.org/lkml/2015/10/14/970

To fix this, we define PPC_ATOMIC_ENTRY_BARRIER as "sync" to guarantee
the fully-ordered semantics.

This also makes futex atomics fully ordered, which can avoid possible
memory ordering problems if userspace code relies on futex system call
for fully ordered semantics.

Fixes: b97021f85517 ("powerpc: Fix atomic_xxx_return barrier semantics")
Signed-off-by: Boqun Feng 
Reviewed-by: Paul E. McKenney 
Acked-by: Peter Zijlstra (Intel) 
Signed-off-by: Michael Ellerman 
Signed-off-by: Greg Kroah-Hartman

Partial revert of "powerpc: Individual System V IPC system calls"

2015-12-16T10:52:32+00:00

This partially reverts commit a34236155afb1cc41945e58388ac988431bcb0b8.

While reviewing the glibc patch to exploit the individual IPC calls,
Arnd & Andreas noticed that we were still requiring userspace to pass
IPC_64 in order to get the new style IPC API.

With a bit of cleanup in the kernel we can drop that requirement, and
instead only provide the new style API, which will simplify things for
userspace.

Rather than try and sneak that patch into 4.4, instead we will drop the
individual IPC calls for powerpc, and merge them again in 4.5 once the
cleanup patch has gone in.

Because we've already added sys_mlock2() as syscall #378, we don't do a
full revert of the IPC calls. Instead we drop the __NR #defines, and
send those now undefined syscall numbers to sys_ni_syscall(). This
leaves a gap in the syscall numbers, but we'll reuse them when we merge
the individual IPC calls.

Signed-off-by: Michael Ellerman 
Acked-by: Arnd Bergmann

powerpc/tm: Block signal return setting invalid MSR state

2015-11-23T09:06:31+00:00

Currently we allow both the MSR T and S bits to be set by userspace on
a signal return.  Unfortunately this is a reserved configuration and
will cause a TM Bad Thing exception if attempted (via rfid).

This patch checks for this case in both the 32 and 64 bit signals
code.  If both T and S are set, we mark the context as invalid.

Found using a syscall fuzzer.

Fixes: 2b0a576d15e0 ("powerpc: Add new transactional memory state to the signal context")
Cc: stable@vger.kernel.org # v3.9+
Signed-off-by: Michael Neuling 
Signed-off-by: Michael Ellerman

powerpc: Wire up sys_mlock2()

2015-11-16T06:05:53+00:00

The selftest passes on 64-bit LE and 32-bit BE.

Signed-off-by: Michael Ellerman

kmap_atomic_to_page() has no users, remove it

2015-11-09T23:11:24+00:00

Removal started in commit 5bbeed12bdc3 ("sparc32: drop unused
kmap_atomic_to_page").  Let's do it across the whole tree.

Signed-off-by: Nicolas Pitre 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds