ppc64 should not be depending on DSISR_PROTFAULT and it's unexpected if
they are triggered.  This patch adds warnings just in case they are being
accidentally depended upon.
Signed-off-by: NMel Gorman <mgorman@suse.de>
Acked-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Tested-by: NSasha Levin <sasha.levin@oracle.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Dave Jones <davej@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The core VM already knows about VM_FAULT_SIGBUS, but cannot return a
"you should SIGSEGV" error, because the SIGSEGV case was generally
handled by the caller - usually the architecture fault handler.

That results in lots of duplication - all the architecture fault
handlers end up doing very similar "look up vma, check permissions, do
retries etc" - but it generally works.  However, there are cases where
the VM actually wants to SIGSEGV, and applications _expect_ SIGSEGV.

In particular, when accessing the stack guard page, libsigsegv expects a
SIGSEGV.  And it usually got one, because the stack growth is handled by
that duplicated architecture fault handler.

However, when the generic VM layer started propagating the error return
from the stack expansion in commit fee7e49d ("mm: propagate error
from stack expansion even for guard page"), that now exposed the
existing VM_FAULT_SIGBUS result to user space.  And user space really
expected SIGSEGV, not SIGBUS.

To fix that case, we need to add a VM_FAULT_SIGSEGV, and teach all those
duplicate architecture fault handlers about it.  They all already have
the code to handle SIGSEGV, so it's about just tying that new return
value to the existing code, but it's all a bit annoying.

This is the mindless minimal patch to do this.  A more extensive patch
would be to try to gather up the mostly shared fault handling logic into
one generic helper routine, and long-term we really should do that
cleanup.

Just from this patch, you can generally see that most architectures just
copied (directly or indirectly) the old x86 way of doing things, but in
the meantime that original x86 model has been improved to hold the VM
semaphore for shorter times etc and to handle VM_FAULT_RETRY and other
"newer" things, so it would be a good idea to bring all those
improvements to the generic case and teach other architectures about
them too.
Reported-and-tested-by: NTakashi Iwai <tiwai@suse.de>
Tested-by: NJan Engelhardt <jengelh@inai.de>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> # "s390 still compiles and boots"
Cc: linux-arch@vger.kernel.org
Cc: stable@vger.kernel.org
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch makes copro_calculate_slb() mask the ESID by the correct mask
for 1T vs 256M segments.

This has no effect by itself as the extra bits were ignored, but it
makes debugging the segment table entries easier and means that we can
directly compare the ESID values for duplicates without needing to worry
about masking in the comparison.

This will be used to simplify a comparison in the following patch.
Signed-off-by: NIan Munsie <imunsie@au1.ibm.com>
Reviewed-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

This adds hooks into the core powerpc mm code for cxl.

The core powerpc code sometimes uses local tlbie. Unfortunately this won't
work with the current cxl driver as it relies on snooping tlbie broadcasts.

The cxl hardware can have TLB entries invalidated via MMIO but this is not
currently supported by the driver. In future we can make local tlbie smarter so
that it invalidates cxl contexts via MMIO when it needs to but for now we have
this workaround.

This workaround checks for any active cxl contexts and if so, disables local
tlbie.

This also adds a hook for when SLBs are invalidated. This ensures any
corresponding SLBs in cxl are also invalidated at the same time. This is
required for segment demotion.
Signed-off-by: NIan Munsie <imunsie@au1.ibm.com>
Signed-off-by: NMichael Neuling <mikey@neuling.org>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

This moves spu_flush_all_slbs() into a generic call copro_flush_all_slbs().

This will be useful when we add cxl which also needs a similar SLB flush call.
Signed-off-by: NIan Munsie <imunsie@au1.ibm.com>
Signed-off-by: NMichael Neuling <mikey@neuling.org>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

__spu_trap_data_seg() currently contains code to determine the VSID and ESID
required for a particular EA and mm struct.

This code is generically useful for other co-processors. This moves the code of
the cell platform so it can be used by other powerpc code. It also adds 1TB
segment handling which Cell didn't support.  The new function is called
copro_calculate_slb().

This also moves the internal struct spu_slb to a generic struct copro_slb which
is now used in the Cell and copro code.  We use this new struct instead of
passing around esid and vsid parameters.
Signed-off-by: NIan Munsie <imunsie@au1.ibm.com>
Signed-off-by: NMichael Neuling <mikey@neuling.org>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Currently spu_handle_mm_fault() is in the cell platform.

This code is generically useful for other non-cell co-processors on powerpc.

This patch moves this function out of the cell platform into arch/powerpc/mm so
that others may use it.
Signed-off-by: NIan Munsie <imunsie@au1.ibm.com>
Signed-off-by: NMichael Neuling <mikey@neuling.org>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

All these files were including module.h just for the basic
EXPORT_SYMBOL infrastructure.  We can shift them off to the
export.h header which is a way smaller footprint and thus
realize some compile time gains.
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>

This allows the callers to now pass down the full set of FAULT_FLAG_xyz
flags to handle_mm_fault().  All callers have been (mechanically)
converted to the new calling convention, there's almost certainly room
for architectures to clean up their code and then add FAULT_FLAG_RETRY
when that support is added.
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Currently, spu_handle_mm_fault disregards the 'ret' variable and always
returns -EFAULT on error.

This change refactos spu_handle_mm_fault a little, to return the
ret variable as appropriate. This allows us to combine the error and
sucess paths.

Also, remove the #if-0-ed IS_VALID_EA() check, it has never been
used.
Signed-off-by: NJeremy Kerr <jk@ozlabs.org>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Currently, part of the spufs code (switch.o, lscsa_alloc.o and fault.o)
is compiled directly into the kernel.

This change moves these components of spufs into the kernel.

The lscsa and switch objects are fairly straightforward to move in.

For the fault.o module, we split the fault-handling code into two
parts: a/p/p/c/spu_fault.c and a/p/p/c/spufs/fault.c. The former is for
the in-kernel spu_handle_mm_fault function, and we move the rest of the
fault-handling code into spufs.
Signed-off-by: NJeremy Kerr <jk@ozlabs.org>
Signed-off-by: NPaul Mackerras <paulus@samba.org>