linux-toradex.git/arch/powerpc, branch v3.4.73

powerpc/signals: Improved mark VSX not saved with small contexts fix

2013-12-04T18:50:33+00:00

commit ec67ad82814bee92251fd963bf01c7a173856555 upstream.

In a recent patch:
  commit c13f20ac48328b05cd3b8c19e31ed6c132b44b42
  Author: Michael Neuling 
  powerpc/signals: Mark VSX not saved with small contexts

We fixed an issue but an improved solution was later discussed after the patch
was merged.

Firstly, this patch doesn't handle the 64bit signals case, which could also hit
this issue (but has never been reported).

Secondly, the original patch isn't clear what MSR VSX should be set to.  The
new approach below always clears the MSR VSX bit (to indicate no VSX is in the
context) and sets it only in the specific case where VSX is available (ie. when
VSX has been used and the signal context passed has space to provide the
state).

This reverts the original patch and replaces it with the improved solution.  It
also adds a 64 bit version.

Signed-off-by: Michael Neuling 
Signed-off-by: Benjamin Herrenschmidt 
Signed-off-by: Greg Kroah-Hartman

powerpc/signals: Mark VSX not saved with small contexts

2013-11-29T18:50:36+00:00

commit c13f20ac48328b05cd3b8c19e31ed6c132b44b42 upstream.

The VSX MSR bit in the user context indicates if the context contains VSX
state.  Currently we set this when the process has touched VSX at any stage.

Unfortunately, if the user has not provided enough space to save the VSX state,
we can't save it but we currently still set the MSR VSX bit.

This patch changes this to clear the MSR VSX bit when the user doesn't provide
enough space.  This indicates that there is no valid VSX state in the user
context.

This is needed to support get/set/make/swapcontext for applications that use
VSX but only provide a small context.  For example, getcontext in glibc
provides a smaller context since the VSX registers don't need to be saved over
the glibc function call.  But since the program calling getcontext may have
used VSX, the kernel currently says the VSX state is valid when it's not.  If
the returned context is then used in setcontext (ie. a small context without
VSX but with MSR VSX set), the kernel will refuse the context.  This situation
has been reported by the glibc community.

Based on patch from Carlos O'Donell.

Tested-by: Haren Myneni 
Signed-off-by: Michael Neuling 
Signed-off-by: Benjamin Herrenschmidt 
Signed-off-by: Greg Kroah-Hartman

powerpc/powernv: Add PE to its own PELTV

2013-11-29T18:50:36+00:00

commit 631ad691b5818291d89af9be607d2fe40be0886e upstream.

We need add PE to its own PELTV. Otherwise, the errors originated
from the PE might contribute to other PEs. In the result, we can't
clear up the error successfully even we're checking and clearing
errors during access to PCI config space.

Reported-by: kalshett@in.ibm.com
Signed-off-by: Gavin Shan 
Signed-off-by: Benjamin Herrenschmidt 
Signed-off-by: Greg Kroah-Hartman

powerpc/vio: use strcpy in modalias_show

2013-11-29T18:50:36+00:00

commit 411cabf79e684171669ad29a0628c400b4431e95 upstream.

Commit e82b89a6f19bae73fb064d1b3dd91fcefbb478f4 used strcat instead of
strcpy which can result in an overflow of newlines on the buffer.

Signed-off-by: Prarit Bhargava
Cc: benh@kernel.crashing.org
Cc: ben@decadent.org.uk
Signed-off-by: Benjamin Herrenschmidt 
Signed-off-by: Greg Kroah-Hartman

KVM: PPC: Book3S HV: Fix typo in saving DSCR

2013-10-22T08:02:25+00:00

commit cfc860253abd73e1681696c08ea268d33285a2c4 upstream.

This fixes a typo in the code that saves the guest DSCR (Data Stream
Control Register) into the kvm_vcpu_arch struct on guest exit.  The
effect of the typo was that the DSCR value was saved in the wrong place,
so changes to the DSCR by the guest didn't persist across guest exit
and entry, and some host kernel memory got corrupted.

Signed-off-by: Paul Mackerras 
Acked-by: Alexander Graf 
Signed-off-by: Paolo Bonzini 
Signed-off-by: Greg Kroah-Hartman

powerpc: Fix parameter clobber in csum_partial_copy_generic()

2013-10-13T22:42:48+00:00

commit d9813c3681a36774b254c0cdc9cce53c9e22c756 upstream.

The csum_partial_copy_generic() uses register r7 to adjust the remaining
bytes to process.  Unfortunately, r7 also holds a parameter, namely the
address of the flag to set in case of access exceptions while reading
the source buffer.  Lacking a quantum implementation of PowerPC, this
commit instead uses register r9 to do the adjusting, leaving r7's
pointer uncorrupted.

Signed-off-by: Paul E. McKenney 
Signed-off-by: Anton Blanchard 
Signed-off-by: Benjamin Herrenschmidt 
Signed-off-by: Greg Kroah-Hartman

powerpc/vio: Fix modalias_show return values

2013-10-13T22:42:48+00:00

commit e82b89a6f19bae73fb064d1b3dd91fcefbb478f4 upstream.

modalias_show() should return an empty string on error, not -ENODEV.

This causes the following false and annoying error:

> find /sys/devices -name modalias -print0 | xargs -0 cat >/dev/null
cat: /sys/devices/vio/4000/modalias: No such device
cat: /sys/devices/vio/4001/modalias: No such device
cat: /sys/devices/vio/4002/modalias: No such device
cat: /sys/devices/vio/4004/modalias: No such device
cat: /sys/devices/vio/modalias: No such device

Signed-off-by: Prarit Bhargava 
Signed-off-by: Benjamin Herrenschmidt 
Signed-off-by: Greg Kroah-Hartman

powerpc/iommu: Use GFP_KERNEL instead of GFP_ATOMIC in iommu_init_table()

2013-10-13T22:42:48+00:00

commit 1cf389df090194a0976dc867b7fffe99d9d490cb upstream.

Under heavy (DLPAR?) stress, we tripped this panic() in
arch/powerpc/kernel/iommu.c::iommu_init_table():

	page = alloc_pages_node(nid, GFP_ATOMIC, get_order(sz));
	if (!page)
		panic("iommu_init_table: Can't allocate %ld bytes\n", sz);

Before the panic() we got a page allocation failure for an order-2
allocation. There appears to be memory free, but perhaps not in the
ATOMIC context. I looked through all the call-sites of
iommu_init_table() and didn't see any obvious reason to need an ATOMIC
allocation. Most call-sites in fact have an explicit GFP_KERNEL
allocation shortly before the call to iommu_init_table(), indicating we
are not in an atomic context. There is some indirection for some paths,
but I didn't see any locks indicating that GFP_KERNEL is inappropriate.

With this change under the same conditions, we have not been able to
reproduce the panic.

Signed-off-by: Nishanth Aravamudan 
Signed-off-by: Benjamin Herrenschmidt 
Signed-off-by: Greg Kroah-Hartman

powerpc: Handle unaligned ldbrx/stdbrx

2013-09-27T00:15:30+00:00

commit 230aef7a6a23b6166bd4003bfff5af23c9bd381f upstream.

Normally when we haven't implemented an alignment handler for
a load or store instruction the process will be terminated.

The alignment handler uses the DSISR (or a pseudo one) to locate
the right handler. Unfortunately ldbrx and stdbrx overlap lfs and
stfs so we incorrectly think ldbrx is an lfs and stdbrx is an
stfs.

This bug is particularly nasty - instead of terminating the
process we apply an incorrect fixup and continue on.

With more and more overlapping instructions we should stop
creating a pseudo DSISR and index using the instruction directly,
but for now add a special case to catch ldbrx/stdbrx.

Signed-off-by: Anton Blanchard 
Signed-off-by: Benjamin Herrenschmidt 
Signed-off-by: Greg Kroah-Hartman

powerpc: Work around gcc miscompilation of __pa() on 64-bit

2013-09-08T04:58:14+00:00

commit bdbc29c19b2633b1d9c52638fb732bcde7a2031a upstream.

On 64-bit, __pa(&static_var) gets miscompiled by recent versions of
gcc as something like:

        addis 3,2,.LANCHOR1+4611686018427387904@toc@ha
        addi 3,3,.LANCHOR1+4611686018427387904@toc@l

This ends up effectively ignoring the offset, since its bottom 32 bits
are zero, and means that the result of __pa() still has 0xC in the top
nibble.  This happens with gcc 4.8.1, at least.

To work around this, for 64-bit we make __pa() use an AND operator,
and for symmetry, we make __va() use an OR operator.  Using an AND
operator rather than a subtraction ends up with slightly shorter code
since it can be done with a single clrldi instruction, whereas it
takes three instructions to form the constant (-PAGE_OFFSET) and add
it on.  (Note that MEMORY_START is always 0 on 64-bit.)

Signed-off-by: Paul Mackerras 
Signed-off-by: Benjamin Herrenschmidt 
Signed-off-by: Greg Kroah-Hartman