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7 years agopowerpc/mm/radix: Don't do page walk cache flush when doing full mm flush
Aneesh Kumar K.V [Sat, 1 Apr 2017 14:41:47 +0000 (20:11 +0530)]
powerpc/mm/radix: Don't do page walk cache flush when doing full mm flush

For fullmm tlb flush, we do a flush with RIC_FLUSH_ALL which will invalidate all
related caches (radix__tlb_flush()). Hence the pwc flush is not needed.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/powernv: Add OPAL exports attributes to sysfs
Matt Brown [Wed, 29 Mar 2017 23:28:01 +0000 (10:28 +1100)]
powerpc/powernv: Add OPAL exports attributes to sysfs

New versions of OPAL have a device node /ibm,opal/firmware/exports, each
property of which describes a range of memory in OPAL that Linux might
want to export to userspace for debugging.

This patch adds a sysfs file under 'opal/exports' for each property
found there, and makes it read-only by root.

Signed-off-by: Matt Brown <matthew.brown.dev@gmail.com>
[mpe: Drop counting of props, rename to attr, free on sysfs error, c'log]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/prom: Increase minimum RMA size to 512MB
Sukadev Bhattiprolu [Mon, 27 Mar 2017 23:43:14 +0000 (19:43 -0400)]
powerpc/prom: Increase minimum RMA size to 512MB

When booting very large systems with a large initrd, we run out of
space early in boot for either RTAS or the flattened device tree (FDT).
Boot fails with messages like:

Could not allocate memory for RTAS
or
No memory for flatten_device_tree (no room)

Increasing the minimum RMA size to 512MB fixes the problem. This
should not have an impact on smaller LPARs (with 256MB memory),
as the firmware will cap the RMA to the memory assigned to the LPAR.

Fix is based on input/discussions with Michael Ellerman. Thanks to
Praveen K. Pandey for testing on a large system.

Reported-by: Praveen K. Pandey <preveen.pandey@in.ibm.com>
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/powernv: Introduce address translation services for Nvlink2
Alistair Popple [Mon, 3 Apr 2017 09:51:44 +0000 (19:51 +1000)]
powerpc/powernv: Introduce address translation services for Nvlink2

Nvlink2 supports address translation services (ATS) allowing devices
to request address translations from an mmu known as the nest MMU
which is setup to walk the CPU page tables.

To access this functionality certain firmware calls are required to
setup and manage hardware context tables in the nvlink processing unit
(NPU). The NPU also manages forwarding of TLB invalidates (known as
address translation shootdowns/ATSDs) to attached devices.

This patch exports several methods to allow device drivers to register
a process id (PASID/PID) in the hardware tables and to receive
notification of when a device should stop issuing address translation
requests (ATRs). It also adds a fault handler to allow device drivers
to demand fault pages in.

Signed-off-by: Alistair Popple <alistair@popple.id.au>
[mpe: Fix up comment formatting, use flush_tlb_mm()]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/powernv: Add sanity checks to pnv_pci_get_{gpu|npu}_dev
Alistair Popple [Mon, 3 Apr 2017 09:51:43 +0000 (19:51 +1000)]
powerpc/powernv: Add sanity checks to pnv_pci_get_{gpu|npu}_dev

The pnv_pci_get_{gpu|npu}_dev functions are used to find associations
between nvlink PCIe devices and standard PCIe devices. However they
lacked basic sanity checking which results in NULL pointer
dereferencing if they are incorrect called can be harder to spot than
an explicit WARN_ON.

Signed-off-by: Alistair Popple <alistair@popple.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agodrivers/of/base.c: Add of_property_read_u64_index
Alistair Popple [Mon, 3 Apr 2017 09:51:42 +0000 (19:51 +1000)]
drivers/of/base.c: Add of_property_read_u64_index

There is of_property_read_u32_index but no u64 variant. This patch
adds one similar to the u32 version for u64.

Signed-off-by: Alistair Popple <alistair@popple.id.au>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/mm: Remove stale comment about the DART hole
Oliver O'Halloran [Mon, 3 Apr 2017 08:09:06 +0000 (18:09 +1000)]
powerpc/mm: Remove stale comment about the DART hole

The code to fix the problem it describes was removed in commit
c40785ad305b ("powerpc/dart: Use a cachable DART"), and it uses the
stupid comment style. Away it goooooooooooooes!

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc: Avoid taking a data miss on every userspace instruction miss
Anton Blanchard [Mon, 3 Apr 2017 06:41:02 +0000 (16:41 +1000)]
powerpc: Avoid taking a data miss on every userspace instruction miss

Early on in do_page_fault() we call store_updates_sp(), regardless of
the type of exception. For an instruction miss this doesn't make
sense, because we only use this information to detect if a data miss
is the result of a stack expansion instruction or not.

Worse still, it results in a data miss within every userspace
instruction miss handler, because we try and load the very instruction
we are about to install a pte for!

A simple exec microbenchmark runs 6% faster on POWER8 with this fix:

 #include <stdlib.h>
 #include <stdio.h>
 #include <unistd.h>

int main(int argc, char *argv[])
{
unsigned long left = atol(argv[1]);
char leftstr[16];

if (left-- == 0)
return 0;

sprintf(leftstr, "%ld", left);
execlp(argv[0], argv[0], leftstr, NULL);
perror("exec failed\n");

return 0;
}

Pass the number of iterations on the command line (eg 10000) and time
how long it takes to execute.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/book3s: Print task info if we take a machine check in user mode
Michael Ellerman [Mon, 3 Apr 2017 05:29:34 +0000 (15:29 +1000)]
powerpc/book3s: Print task info if we take a machine check in user mode

For an MCE (Machine Check Exception) that hits while in user mode
MSR(PR=1), print the task info to the console MCE error log. This may
help to identify an application that triggered the MCE.

After this patch the MCE console looks like:

  Severe Machine check interrupt [Recovered]
    NIP: [0000000010039778] PID: 762 Comm: ebizzy
    Initiator: CPU
    Error type: SLB [Multihit]
      Effective address: 0000000010039778

  Severe Machine check interrupt [Not recovered]
    NIP: [0000000010039778] PID: 763 Comm: ebizzy
    Initiator: CPU
    Error type: UE [Page table walk ifetch]
      Effective address: 0000000010039778
  ebizzy[763]: unhandled signal 7 at 0000000010039778 nip 0000000010039778 lr 0000000010001b44 code 30004

Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/book3s: Print the kernel function name in machine check
Mahesh Salgaonkar [Tue, 28 Mar 2017 13:45:04 +0000 (19:15 +0530)]
powerpc/book3s: Print the kernel function name in machine check

For D-side errors we print the load/store address that caused the
machine check as 'Effective address'. But the instruction that may have
caused the machine check can also be helpful, so in addition to printing
the NIP, also print the kernel function name as well.

After this patch the MCE console log would look like:

  Severe Machine check interrupt [Recovered]
    NIP [d00000001bc70194]: init_module+0x194/0x2b0 [bork_kernel]
    Initiator: CPU
    Error type: SLB [Parity]
      Effective address: d000000026de0000

Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/mm: Enable mappings above 128TB
Aneesh Kumar K.V [Thu, 30 Mar 2017 11:05:21 +0000 (16:35 +0530)]
powerpc/mm: Enable mappings above 128TB

Not all user space application is ready to handle wide addresses. It's
known that at least some JIT compilers use higher bits in pointers to
encode their information. It collides with valid pointers with 512TB
addresses and leads to crashes.

To mitigate this, we are not going to allocate virtual address space
above 128TB by default.

But userspace can ask for allocation from full address space by
specifying hint address (with or without MAP_FIXED) above 128TB.

If hint address set above 128TB, but MAP_FIXED is not specified, we try
to look for unmapped area by specified address. If it's already
occupied, we look for unmapped area in *full* address space, rather than
from 128TB window.

This approach helps to easily make application's memory allocator aware
about large address space without manually tracking allocated virtual
address space.

This is going to be a per mmap decision. ie, we can have some mmaps with
larger addresses and other that do not.

A sample memory layout looks like:

  10000000-10010000 r-xp 00000000 fc:00 9057045          /home/max_addr_512TB
  10010000-10020000 r--p 00000000 fc:00 9057045          /home/max_addr_512TB
  10020000-10030000 rw-p 00010000 fc:00 9057045          /home/max_addr_512TB
  10029630000-10029660000 rw-p 00000000 00:00 0          [heap]
  7fff834a0000-7fff834b0000 rw-p 00000000 00:00 0
  7fff834b0000-7fff83670000 r-xp 00000000 fc:00 9177190  /lib/powerpc64le-linux-gnu/libc-2.23.so
  7fff83670000-7fff83680000 r--p 001b0000 fc:00 9177190  /lib/powerpc64le-linux-gnu/libc-2.23.so
  7fff83680000-7fff83690000 rw-p 001c0000 fc:00 9177190  /lib/powerpc64le-linux-gnu/libc-2.23.so
  7fff83690000-7fff836a0000 rw-p 00000000 00:00 0
  7fff836a0000-7fff836c0000 r-xp 00000000 00:00 0        [vdso]
  7fff836c0000-7fff83700000 r-xp 00000000 fc:00 9177193  /lib/powerpc64le-linux-gnu/ld-2.23.so
  7fff83700000-7fff83710000 r--p 00030000 fc:00 9177193  /lib/powerpc64le-linux-gnu/ld-2.23.so
  7fff83710000-7fff83720000 rw-p 00040000 fc:00 9177193  /lib/powerpc64le-linux-gnu/ld-2.23.so
  7fffdccf0000-7fffdcd20000 rw-p 00000000 00:00 0        [stack]
  1000000000000-1000000010000 rw-p 00000000 00:00 0
  1ffff83710000-1ffff83720000 rw-p 00000000 00:00 0

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/mm: Switch some TASK_SIZE checks to use mm_context addr_limit
Aneesh Kumar K.V [Wed, 22 Mar 2017 03:37:01 +0000 (09:07 +0530)]
powerpc/mm: Switch some TASK_SIZE checks to use mm_context addr_limit

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/pseries: Skip using reserved virtual address range
Aneesh Kumar K.V [Wed, 22 Mar 2017 03:37:00 +0000 (09:07 +0530)]
powerpc/pseries: Skip using reserved virtual address range

Now that we use all the available virtual address range, we need to make
sure we don't generate VSID such that it overlaps with the reserved vsid
range. Reserved vsid range include the virtual address range used by the
adjunct partition and also the VRMA virtual segment. We find the context
value that can result in generating such a VSID and reserve it early in
boot.

We don't look at the adjunct range, because for now we disable the
adjunct usage in a Linux LPAR via CAS interface.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
[mpe: Rewrite hash__reserve_context_id(), move the rest into pseries]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/mm/hash: Store addr_limit in PACA
Aneesh Kumar K.V [Wed, 22 Mar 2017 03:36:59 +0000 (09:06 +0530)]
powerpc/mm/hash: Store addr_limit in PACA

We optmize the slice page size array copy to paca by copying only the
range based on addr_limit. This will require us to not look at page size
array beyond addr_limit in PACA on slb fault. To enable that copy task
size to paca which will be used during slb fault.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
[mpe: Rename from task_size to addr_limit, consolidate #ifdefs]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/mm: Add addr_limit to mm_context and use it to derive max slice index
Aneesh Kumar K.V [Wed, 22 Mar 2017 03:36:58 +0000 (09:06 +0530)]
powerpc/mm: Add addr_limit to mm_context and use it to derive max slice index

In the followup patch, we will increase the slice array size to handle
512TB range, but will limit the max addr to 128TB. Avoid doing
unnecessary computation and avoid doing slice mask related operation
above address limit.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/mm/hash: Increase VA range to 128TB
Aneesh Kumar K.V [Wed, 22 Mar 2017 03:36:57 +0000 (09:06 +0530)]
powerpc/mm/hash: Increase VA range to 128TB

We update the hash linux page table layout such that we can support
512TB. But we limit the TASK_SIZE to 128TB. We can switch to 128TB by
default without conditional because that is the max virtual address
supported by other architectures. We will later add a mechanism to
on-demand increase the application's effective address range to 512TB.

Having the page table layout changed to accommodate 512TB makes testing
large memory configuration easier with less code changes to kernel

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/mm/hash: Convert mask to unsigned long
Aneesh Kumar K.V [Wed, 22 Mar 2017 03:36:56 +0000 (09:06 +0530)]
powerpc/mm/hash: Convert mask to unsigned long

This doesn't have any functional change. But helps in avoiding mistakes
in case the shift bit changes

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/mm/hash: Support 68 bit VA
Aneesh Kumar K.V [Wed, 29 Mar 2017 06:21:53 +0000 (17:21 +1100)]
powerpc/mm/hash: Support 68 bit VA

Inorder to support large effective address range (512TB), we want to
increase the virtual address bits to 68. But we do have platforms like
p4 and p5 that can only do 65 bit VA. We support those platforms by
limiting context bits on them to 16.

The protovsid -> vsid conversion is verified to work with both 65 and 68
bit va values. I also documented the restrictions in a table format as
part of code comments.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/mm/hash: Check for non-kernel address in get_kernel_vsid()
Michael Ellerman [Wed, 29 Mar 2017 12:10:34 +0000 (23:10 +1100)]
powerpc/mm/hash: Check for non-kernel address in get_kernel_vsid()

get_kernel_vsid() has a very stern comment saying that it's only valid
for kernel addresses, but there's nothing in the code to enforce that.

Rather than hoping our callers are well behaved, add a check and return
a VSID of 0 (invalid).

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/mm/hash: Use context ids 1-4 for the kernel
Aneesh Kumar K.V [Wed, 29 Mar 2017 12:10:22 +0000 (23:10 +1100)]
powerpc/mm/hash: Use context ids 1-4 for the kernel

Currently we use the top 4 context ids (0x7fffc-0x7ffff) for the kernel.
Kernel VSIDs are built using these top context values and effective the
segement ID. In subsequent patches we want to increase the max effective
address to 512TB. We will achieve that by increasing the effective
segment IDs there by increasing virtual address range.

We will be switching to a 68bit virtual address in the following patch.
But platforms like Power4 and Power5 only support a 65 bit virtual
address. We will handle that by limiting the context bits to 16 instead
of 19 on those platforms. That means the max context id will have a
different value on different platforms.

So that we don't have to deal with the kernel context ids changing
between different platforms, move the kernel context ids down to use
context ids 1-4.

We can't use segment 0 of context-id 0, because that maps to VSID 0,
which we want to keep as invalid, so we avoid context-id 0 entirely.
Similarly we can't use the last segment of the maximum context, so we
avoid it too.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
[mpe: Switch from 0-3 to 1-4 so VSID=0 remains invalid]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/mm: Split radix vs hash mm context initialisation
Michael Ellerman [Wed, 29 Mar 2017 11:36:56 +0000 (22:36 +1100)]
powerpc/mm: Split radix vs hash mm context initialisation

Complete the split of the radix vs hash mm context initialisation.

This is mostly code movement, with the exception that we now limit the
context allocation to PRTB_ENTRIES - 1 on radix.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/mm/hash: Pull hash constants into hash__alloc_context_id()
Michael Ellerman [Wed, 29 Mar 2017 11:10:45 +0000 (22:10 +1100)]
powerpc/mm/hash: Pull hash constants into hash__alloc_context_id()

The min and max context id values used in alloc_context_id() are
currently the right values for use on hash, and happen to also be safe
for use on radix.

But we need to change that in a subsequent patch, so make the min/max
ids parameters and pull the hash values into hsah__alloc_context_id().

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/mm/hash: Abstract context id allocation for KVM
Michael Ellerman [Wed, 29 Mar 2017 11:00:46 +0000 (22:00 +1100)]
powerpc/mm/hash: Abstract context id allocation for KVM

KVM wants to be able to allocate an MMU context id, which it does
currently by calling __init_new_context().

We're about to rework that code, so provide a wrapper for KVM so it
can not worry about the details.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/mm/slice: Update slice mask printing to use bitmap printing.
Aneesh Kumar K.V [Wed, 22 Mar 2017 03:36:52 +0000 (09:06 +0530)]
powerpc/mm/slice: Update slice mask printing to use bitmap printing.

We now get output like below which is much better.

[    0.935306]  good_mask low_slice: 0-15
[    0.935360]  good_mask high_slice: 0-511

Compared to

[    0.953414]  good_mask:1111111111111111 - 1111111111111.........

I also fixed an error with slice_dbg printing.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/mm/slice: Move slice_mask struct definition to slice.c
Aneesh Kumar K.V [Wed, 22 Mar 2017 03:36:51 +0000 (09:06 +0530)]
powerpc/mm/slice: Move slice_mask struct definition to slice.c

This structure definition need not be in a header since this is used only by
slice.c file. So move it to slice.c. This also allow us to use SLICE_NUM_HIGH
instead of 64.

I also switch the low_slices type to u64 from u16. This doesn't have an impact
on size of struct due to padding added with u16 type. This helps in using
bitmap printing function for printing slice mask.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/mm: Remove checks that TASK_SIZE_USER64 is too small
Aneesh Kumar K.V [Wed, 22 Mar 2017 03:36:50 +0000 (09:06 +0530)]
powerpc/mm: Remove checks that TASK_SIZE_USER64 is too small

Remove the checks that TASK_SIZE_USER64 is smaller than H_PGTABLE_RANGE
and USER_VSID_RANGE.

In a following patch we will deliberately add support for a TASK_SIZE
smaller than both ranges, so this will no longer be an error condition.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
[mpe: Keep the check in pgtable_64.c that we don't exceed USER_VSID_RANGE]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/mm: Move copy_mm_to_paca to paca.c
Aneesh Kumar K.V [Wed, 22 Mar 2017 03:36:49 +0000 (09:06 +0530)]
powerpc/mm: Move copy_mm_to_paca to paca.c

We also update the function arg to struct mm_struct. Move this so that function
finds the definition of struct mm_struct. No functional change in this patch.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/mm/slice: Update the function prototype
Aneesh Kumar K.V [Wed, 22 Mar 2017 03:36:48 +0000 (09:06 +0530)]
powerpc/mm/slice: Update the function prototype

This avoid copying the slice_mask struct as function return value

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/mm/slice: Convert slice_mask high slice to a bitmap
Aneesh Kumar K.V [Wed, 22 Mar 2017 03:36:47 +0000 (09:06 +0530)]
powerpc/mm/slice: Convert slice_mask high slice to a bitmap

In followup patch we want to increase the va range which will result
in us requiring high_slices to have more than 64 bits. To enable this
convert high_slices to bitmap. We keep the number bits same in this patch
and later change that to higher value

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
[mpe: Fold in fix to use bitmap_empty()]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/mm: Move hash specific pte bits to be top bits of RPN
Aneesh Kumar K.V [Tue, 28 Mar 2017 04:21:12 +0000 (15:21 +1100)]
powerpc/mm: Move hash specific pte bits to be top bits of RPN

We don't support the full 57 bits of physical address and hence can
overload the top bits of RPN as hash specific pte bits.

Add a BUILD_BUG_ON() to enforce the relationship between H_PAGE_F_SECOND
and H_PAGE_F_GIX.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Reviewed-by: Paul Mackerras <paulus@ozlabs.org>
[mpe: Move the BUILD_BUG_ON() into hash_utils_64.c and comment it]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/mm: Lower the max real address to 53 bits
Aneesh Kumar K.V [Tue, 21 Mar 2017 17:29:59 +0000 (22:59 +0530)]
powerpc/mm: Lower the max real address to 53 bits

Max value supported by hardware is 51 bits address. Radix page table define
a slot of 57 bits for future expansion. We restrict the value supported in
linux kernel 53 bits, so that we can use the bits between 57-53 for storing
hash linux page table bits. This is done in the next patch.

This will free up the software page table bits to be used for features
that are needed for both hash and radix. The current hash linux page table
format doesn't have any free software bits. Moving hash linux page table
specific bits to top of RPN field free up the software bits for other purpose.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Reviewed-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/mm: Define all PTE bits based on radix definitions.
Aneesh Kumar K.V [Tue, 21 Mar 2017 17:29:58 +0000 (22:59 +0530)]
powerpc/mm: Define all PTE bits based on radix definitions.

Reviewed-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/mm: Define _PAGE_SOFT_DIRTY unconditionally
Aneesh Kumar K.V [Tue, 21 Mar 2017 17:29:57 +0000 (22:59 +0530)]
powerpc/mm: Define _PAGE_SOFT_DIRTY unconditionally

Conditional PTE bit definition is confusing and results in coding error.

Reviewed-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/mm/hugetlb: Filter out hugepage size not supported by page table layout
Aneesh Kumar K.V [Tue, 21 Mar 2017 17:29:56 +0000 (22:59 +0530)]
powerpc/mm/hugetlb: Filter out hugepage size not supported by page table layout

Without this if firmware reports 1MB page size support we will crash
trying to use 1MB as hugetlb page size.

echo 300 > /sys/kernel/mm/hugepages/hugepages-1024kB/nr_hugepages

kernel BUG at ./arch/powerpc/include/asm/hugetlb.h:19!
.....
....
[c0000000e2c27b30c00000000029dae8 .hugetlb_fault+0x638/0xda0
[c0000000e2c27c30c00000000026fb64 .handle_mm_fault+0x844/0x1d70
[c0000000e2c27d70c00000000004805c .do_page_fault+0x3dc/0x7c0
[c0000000e2c27e30c00000000000ac98 handle_page_fault+0x10/0x30

With fix, we don't enable 1MB as hugepage size.

bash-4.2# cd /sys/kernel/mm/hugepages/
bash-4.2# ls
hugepages-16384kB  hugepages-16777216kB

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/mm: Add translation mode information in /proc/cpuinfo
Aneesh Kumar K.V [Tue, 21 Mar 2017 17:29:55 +0000 (22:59 +0530)]
powerpc/mm: Add translation mode information in /proc/cpuinfo

With this we have on powernv and pseries /proc/cpuinfo reporting

timebase        : 512000000
platform        : PowerNV
model           : 8247-22L
machine         : PowerNV 8247-22L
firmware        : OPAL
MMU : Hash

Reviewed-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/mm/radix: rename _PAGE_LARGE to R_PAGE_LARGE
Aneesh Kumar K.V [Tue, 21 Mar 2017 17:29:54 +0000 (22:59 +0530)]
powerpc/mm/radix: rename _PAGE_LARGE to R_PAGE_LARGE

This bit is only used by radix and it is nice to follow the naming style of having
bit name start with H_/R_ depending on which translation mode they are used.

No functional change in this patch.

Reviewed-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/mm: Cleanup bits definition between hash and radix.
Aneesh Kumar K.V [Tue, 21 Mar 2017 17:29:53 +0000 (22:59 +0530)]
powerpc/mm: Cleanup bits definition between hash and radix.

Define everything based on bits present in pgtable.h. This will help in easily
identifying overlapping bits between hash/radix.

No functional change with this patch.

Reviewed-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/mm/slice: Fix off-by-1 error when computing slice mask
Aneesh Kumar K.V [Tue, 21 Mar 2017 17:29:52 +0000 (22:59 +0530)]
powerpc/mm/slice: Fix off-by-1 error when computing slice mask

For low slice, max addr should be less than 4G. Without limiting this correctly
we will end up with a low slice mask which has 17th bit set. This is not
a problem with the current code because our low slice mask is of type u16. But
in later patch I am switching low slice mask to u64 type and having the 17bit
set result in wrong slice mask which in turn results in mmap failures.

Reviewed-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/mm/nohash: MM_SLICE is only used by book3s 64
Aneesh Kumar K.V [Tue, 21 Mar 2017 17:29:51 +0000 (22:59 +0530)]
powerpc/mm/nohash: MM_SLICE is only used by book3s 64

BOOKE code is dead code as per the Kconfig details. So make it simpler
by enabling MM_SLICE only for book3s_64. The changes w.r.t nohash is just
removing deadcode. W.r.t ppc64, 4k without hugetlb will now enable MM_SLICE.
But that is good, because we reduce one extra variant which probably is not
getting tested much.

Reviewed-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/4xx: Make sam440ep_setup_rtc() init
Yang Shi [Tue, 26 Apr 2016 16:49:38 +0000 (09:49 -0700)]
powerpc/4xx: Make sam440ep_setup_rtc() init

sam440ep_setup_rtc() is just called by machine_device_initcall() so make
it __init.

Signed-off-by: Yang Shi <yang.shi@windriver.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/fadump: Update fadump documentation
Hari Bathini [Thu, 16 Mar 2017 21:05:42 +0000 (02:35 +0530)]
powerpc/fadump: Update fadump documentation

With the unnecessary restriction to reserve memory for fadump at the
top of RAM forgone, update the documentation accordingly.

Signed-off-by: Hari Bathini <hbathini@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/fadump: Reserve memory at an offset closer to bottom of RAM
Hari Bathini [Thu, 16 Mar 2017 21:05:26 +0000 (02:35 +0530)]
powerpc/fadump: Reserve memory at an offset closer to bottom of RAM

Currently, the area to preserve boot memory is reserved at the top of
RAM. This leaves fadump vulnerable to memory hot-remove operations. As
memory for fadump has to be reserved early in the boot process, fadump
can't be registered after a memory hot-remove operation. Though this
problem can't be eleminated completely, the impact can be minimized by
reserving memory at an offset closer to bottom of the RAM. The offset
for fadump memory reservation can be any value greater than fadump boot
memory size.

Signed-off-by: Hari Bathini <hbathini@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/powernv: Handle OPAL_WRONG_STATE in opal_get_sensor_data()
Vipin K Parashar [Fri, 10 Mar 2017 11:57:32 +0000 (17:27 +0530)]
powerpc/powernv: Handle OPAL_WRONG_STATE in opal_get_sensor_data()

OPAL returns OPAL_WRONG_STATE upon failing to provide sensor data due to
core sleeping/offline. Add a check in opal_get_sensor_data() for sensor
read failure with OPAL_WRONG_STATE return code and return -EIO.

Signed-off-by: Vipin K Parashar <vipin@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc: Make /proc/self/stack always print the current stack
Thadeu Lima de Souza Cascardo [Mon, 27 Mar 2017 19:32:33 +0000 (16:32 -0300)]
powerpc: Make /proc/self/stack always print the current stack

For the current task, the kernel stack would only tell the last time the
process was rescheduled, if ever. Use the current stack pointer for the
current task.

Otherwise, every once in a while, the stacktrace printed when reading
/proc/self/stack would look like the process is running in userspace,
while it's not, which some may consider as a bug.

This is also consistent with some other architectures, like x86 and arm,
at least.

Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/64: Don't use early_cpu_has_feature() in cpu_ready_for_interrupts()
Michael Ellerman [Tue, 21 Mar 2017 05:24:38 +0000 (16:24 +1100)]
powerpc/64: Don't use early_cpu_has_feature() in cpu_ready_for_interrupts()

cpu_ready_for_interrupts() is called after feature patching, so there's
no need to use early_cpu_has_feature().

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/configs: Re-enable POWER8 crc32c
Anton Blanchard [Wed, 22 Mar 2017 21:22:01 +0000 (08:22 +1100)]
powerpc/configs: Re-enable POWER8 crc32c

The config option for the POWER8 crc32c recently changed from
CONFIG_CRYPT_CRC32C_VPMSUM to CONFIG_CRYPTO_CRC32C_VPMSUM. Update
the configs.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/configs: Make oprofile a module
Anton Blanchard [Wed, 22 Mar 2017 21:22:00 +0000 (08:22 +1100)]
powerpc/configs: Make oprofile a module

Most people use perf these days, so save about 31kB by making oprofile
a module.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/configs: Re-enable ISO9660_FS as a built-in in 64 bit configs
Anton Blanchard [Wed, 22 Mar 2017 21:21:59 +0000 (08:21 +1100)]
powerpc/configs: Re-enable ISO9660_FS as a built-in in 64 bit configs

It turns out cloud-config uses ISO9660 filesystems to inject
configuration data into cloud images. The cloud-config failures when
ISO9660_FS is not enabled are cryptic, and building it in makes
mainline testing easier, so re-enable it.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/powernv: Fix XSCOM address mangling for form 1 indirect
Michael Neuling [Fri, 24 Mar 2017 10:20:56 +0000 (21:20 +1100)]
powerpc/powernv: Fix XSCOM address mangling for form 1 indirect

POWER9 adds form 1 scoms. The form of the indirection is specified in
the top nibble of the scom address.

Currently we do some (ugly) bit mangling so that we can fit a 64 bit
scom address into the debugfs interface. The current code only shifts
the top bit (indirect bit).

This patch changes it to shift the whole top nibble so that the form
of the indirection is also shifted.

This patch is backwards compatible with older scoms.

(This change isn't required in the arch/powerpc/platforms/powernv/opal-prd.c
scom interface as it passes the whole 64bit scom address without any bit
mangling)

Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/powernv: de-deuplicate OPAL call wrappers
Oliver O'Halloran [Thu, 23 Mar 2017 07:54:01 +0000 (18:54 +1100)]
powerpc/powernv: de-deuplicate OPAL call wrappers

Currently the code to perform an OPAL call is duplicated between the
normal path and path taken when tracepoints are enabled. There's no
real need for this and combining them makes opal_tracepoint_entry
considerably easier to understand.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/xmon: add debugfs entry for xmon
Guilherme G. Piccoli [Wed, 22 Mar 2017 19:27:51 +0000 (16:27 -0300)]
powerpc/xmon: add debugfs entry for xmon

Currently the xmon debugger is set only via kernel boot command-line.
It's disabled by default, and can be enabled with "xmon=on" on the
command-line. Also, xmon may be accessed via sysrq mechanism.
But we cannot enable/disable xmon in runtime, it needs kernel reload.

This patch introduces a debugfs entry for xmon, allowing user to query
its current state and change it if desired. Basically, the "xmon" file
to read from/write to is under the debugfs mount point, on powerpc
directory. It's a simple attribute, value 0 meaning xmon is disabled
and value 1 the opposite. Writing these states to the file will take
immediate effect in the debugger.

Signed-off-by: Guilherme G. Piccoli <gpiccoli@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/xmon: drop the nobt option from xmon plus minor fixes
Guilherme G. Piccoli [Wed, 22 Mar 2017 19:27:50 +0000 (16:27 -0300)]
powerpc/xmon: drop the nobt option from xmon plus minor fixes

The xmon parameter nobt was added long time ago, by commit 26c8af5f01df
("[POWERPC] print backtrace when entering xmon"). The problem that time
was that during a crash in a machine with USB keyboard, xmon wouldn't
respond to commands from the keyboard, so printing the backtrace wouldn't
be possible.

Idea then was to show automatically the backtrace on xmon crash for the
first time it's invoked (if it recovers, next time xmon won't show
backtrace automatically). The nobt parameter was added _only_ to prevent
this automatic trace show. Seems long time ago USB keyboards didn't work
that well!

We don't need this parameter anymore, the feature of auto showing the
backtrace is interesting (imagine a case of auto-reboot script),
so this patch extends the functionality, by always showing the backtrace
automatically when xmon is invoked; it removes the nobt parameter too.

Also, this patch fixes __initdata placement on xmon_early and replaces
__initcall() with modern device_initcall() on sysrq handler.

Signed-off-by: Guilherme G. Piccoli <gpiccoli@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/xmon: Fix an unexpected xmon on/off state change
Pan Xinhui [Wed, 22 Mar 2017 19:27:49 +0000 (16:27 -0300)]
powerpc/xmon: Fix an unexpected xmon on/off state change

Once xmon is triggered by sysrq-x, it is enabled always afterwards even
if it is disabled during boot. This will cause a system reset interrupt
fail to dump. So keep xmon in its original state after exit.

We have several ways to set xmon on or off.
1) by a build config CONFIG_XMON_DEFAULT.
2) by a boot cmdline with xmon or xmon=early or xmon=on to enable xmon
and xmon=off to disable xmon. This value will override that in step 1.
3) by a debugfs interface, as proposed in this patchset.
And this value can override those in step 1 and 2.

Signed-off-by: Pan Xinhui <xinhui.pan@linux.vnet.ibm.com>
Signed-off-by: Guilherme G. Piccoli <gpiccoli@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/64s: POWER8 add missing machine check definitions
Nicholas Piggin [Tue, 14 Mar 2017 12:36:48 +0000 (22:36 +1000)]
powerpc/64s: POWER8 add missing machine check definitions

POWER8 uses bit 36 in SRR1 like POWER9 for i-side machine checks, and
contains several conditions for link timeouts that are not currently
handled.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/64s: Data driven machine check handling
Nicholas Piggin [Tue, 14 Mar 2017 12:36:47 +0000 (22:36 +1000)]
powerpc/64s: Data driven machine check handling

Move the handling (corrective action) of machine checks to the table
based evaluation.

This changes P7 and P8 ERAT flushing from using SLB flush to using ERAT
flush.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/64s: Data driven machine check evaluation
Nicholas Piggin [Tue, 14 Mar 2017 12:36:46 +0000 (22:36 +1000)]
powerpc/64s: Data driven machine check evaluation

Have machine types define i-side and d-side tables to describe their
machine check encodings, and match entries to evaluate (for reporting)
machine checks.

Functionality is mostly unchanged (tested with a userspace harness), but
it does make a change in that it no longer records DAR as the effective
address for those errors where it is specified to be invalid (which is a
reporting change only).

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/64s: Move POWER machine check defines into mce_power.c
Nicholas Piggin [Tue, 14 Mar 2017 12:36:45 +0000 (22:36 +1000)]
powerpc/64s: Move POWER machine check defines into mce_power.c

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/64s: Clean up machine check recovery flushing
Nicholas Piggin [Tue, 14 Mar 2017 12:36:44 +0000 (22:36 +1000)]
powerpc/64s: Clean up machine check recovery flushing

Use the flush function introduced with the POWER9 machine check handler
for POWER7 and 8, rather than open coding it multiple times in callers.

There is a specific ERAT flush type introduced for POWER9, but the
POWER7-8 ERAT errors continue to do SLB flushing (which also flushes
ERAT), so as not to introduce functional changes with this cleanup
patch.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/64s: Machine check print NIP
Nicholas Piggin [Tue, 14 Mar 2017 12:36:43 +0000 (22:36 +1000)]
powerpc/64s: Machine check print NIP

Print the faulting address of the machine check that may help with
debugging. The effective address reported can be a target memory address
rather than the faulting instruction address.

Fix up a dangling bracket while here.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agodrivers/pcmcia: NO_IRQ removal for electra_cf.c
Michael Ellerman [Sat, 10 Sep 2016 10:01:30 +0000 (20:01 +1000)]
drivers/pcmcia: NO_IRQ removal for electra_cf.c

We'd like to eventually remove NO_IRQ on powerpc, so remove usages of it
from electra_cf.c which is a powerpc-only driver.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agoMAINTAINERS: Add file patterns for powerpc device tree bindings
Geert Uytterhoeven [Sun, 12 Mar 2017 13:17:00 +0000 (14:17 +0100)]
MAINTAINERS: Add file patterns for powerpc device tree bindings

Submitters of device tree binding documentation may forget to CC
the subsystem maintainer if this is missing.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc: Fix missing CRCs, add more asm-prototypes.h declarations
Ben Hutchings [Fri, 2 Dec 2016 02:38:38 +0000 (02:38 +0000)]
powerpc: Fix missing CRCs, add more asm-prototypes.h declarations

Add declarations for:
  - __mfdcr, __mtdcr (if CONFIG_PPC_DCR_NATIVE=y; through <asm/dcr.h>)
  - switch_mmu_context (if CONFIG_PPC_BOOK3S_64=n; through <asm/mmu_context.h>)

Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/32: Remove Mac-on-Linux/rtlinux hooks
Ben Hutchings [Fri, 2 Dec 2016 02:35:52 +0000 (02:35 +0000)]
powerpc/32: Remove Mac-on-Linux/rtlinux hooks

The symbols exported for use by MOL/rtlinux aren't getting CRCs and I
was about to fix that. But MOL is dead upstream, and the latest work on
it was to make it use KVM instead of its own kernel module. So remove
them instead.

Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/mm: Move mmap_sem unlocking in do_page_fault()
Laurent Dufour [Tue, 14 Feb 2017 16:45:12 +0000 (17:45 +0100)]
powerpc/mm: Move mmap_sem unlocking in do_page_fault()

Since the fault retry is now handled earlier, we can release the
mmap_sem lock earlier too and remove later unlocking previously done in
mm_fault_error().

Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/mm: Handle VM_FAULT_RETRY earlier
Laurent Dufour [Tue, 14 Feb 2017 16:45:11 +0000 (17:45 +0100)]
powerpc/mm: Handle VM_FAULT_RETRY earlier

In do_page_fault() if handle_mm_fault() returns VM_FAULT_RETRY, retry
the page fault handling before anything else.

This would simplify the handling of the mmap_sem lock in this part of
the code.

Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/mm: Move mmap_sem unlock up from do_sigbus
Laurent Dufour [Tue, 14 Feb 2017 16:45:10 +0000 (17:45 +0100)]
powerpc/mm: Move mmap_sem unlock up from do_sigbus

Move mmap_sem releasing in the do_sigbus()'s unique caller : mm_fault_error()

No functional changes.

Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/powernv/npu: Remove dead iommu code
Alexey Kardashevskiy [Tue, 21 Feb 2017 02:40:20 +0000 (13:40 +1100)]
powerpc/powernv/npu: Remove dead iommu code

PNV_IODA_PE_DEV is only used for NPU devices (emulated PCI bridges
representing NVLink). These are added to IOMMU groups with corresponding
NVIDIA devices after all non-NPU PEs are setup; a special helper -
pnv_pci_ioda_setup_iommu_api() - handles this in pnv_pci_ioda_fixup().

The pnv_pci_ioda2_setup_dma_pe() helper sets up DMA for a PE. It is called
for VFs (so it does not handle NPU case) and PCI bridges but only
IODA1 and IODA2 types. An NPU bridge has its own type id (PNV_PHB_NPU)
so pnv_pci_ioda2_setup_dma_pe() cannot be called on NPU and therefore
(pe->flags & PNV_IODA_PE_DEV) is always "false".

This removes not used iommu_add_device(). This should not cause any
behavioral change.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Acked-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/powernv: Fix it_ops::get() callback to return in cpu endian
Alexey Kardashevskiy [Tue, 21 Feb 2017 02:38:54 +0000 (13:38 +1100)]
powerpc/powernv: Fix it_ops::get() callback to return in cpu endian

The iommu_table_ops callbacks are declared CPU endian as they take and
return "unsigned long"; underlying hardware tables are big-endian.

However get() was missing be64_to_cpu(), this adds the missing conversion.

The only caller of this is crash dump at arch/powerpc/kernel/iommu.c,
iommu_table_clear() which only compares TCE to zero so this change
should not cause behavioral change.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Acked-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/ftrace: Add prototype for prepare_ftrace_return()
Tobin C. Harding [Mon, 6 Mar 2017 08:49:46 +0000 (19:49 +1100)]
powerpc/ftrace: Add prototype for prepare_ftrace_return()

Sparse emits a warning: symbol 'prepare_ftrace_return' was not
declared. Should it be static? prepare_ftrace_return() is called from
assembler and should not be static.

Add a prototype for it to asm-prototypes.h and include that in ftrace.c.

Signed-off-by: Tobin C. Harding <me@tobin.cc>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/swsusp: Include suspend.h to silence sparse warnings
Tobin C. Harding [Mon, 6 Mar 2017 08:25:31 +0000 (19:25 +1100)]
powerpc/swsusp: Include suspend.h to silence sparse warnings

Sparse emits two symbol not declared warnings for swsusp.c. The two
functions, save_processor_state() and restore_processor_state() are
declared already in suspend.h, so include it.

Signed-off-by: Tobin C. Harding <me@tobin.cc>
Reviewed-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/pseries: Move struct hcall_stats to hvCall_inst.c
Tobin C. Harding [Tue, 7 Mar 2017 09:32:42 +0000 (20:32 +1100)]
powerpc/pseries: Move struct hcall_stats to hvCall_inst.c

struct hcall_stats is only used in hvCall_inst.c, so move it there.

Signed-off-by: Tobin C. Harding <me@tobin.cc>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agoselftests/powerpc: Add cache_shape sniff test
Michael Ellerman [Mon, 6 Feb 2017 10:13:28 +0000 (21:13 +1100)]
selftests/powerpc: Add cache_shape sniff test

This is a very basic test of the new cache shape AUXV entries. All it
does at the moment is look for the entries and error out if we don't
find all the ones we expect. Primarily intended for folks bringing up a
new chip to check that the cache info is making it all the way to
userspace correctly.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agoselftests/powerpc: Refactor the AUXV routines
Michael Ellerman [Mon, 6 Feb 2017 10:13:27 +0000 (21:13 +1100)]
selftests/powerpc: Refactor the AUXV routines

Refactor the AUXV routines so they are more composable. In a future test
we want to look for many AUXV entries and we don't want to have to read
/proc/self/auxv each time.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc/64: Allow for THREAD_SIZE > 16k
Hamish Martin [Fri, 24 Feb 2017 00:52:10 +0000 (13:52 +1300)]
powerpc/64: Allow for THREAD_SIZE > 16k

Fix an assembler error when the THREAD_SIZE is greater than 16k.

Signed-off-by: Hamish Martin <hamish.martin@alliedtelesis.co.nz>
Reviewed-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agopowerpc: Move THREAD_SHIFT config to Kconfig
Hamish Martin [Fri, 24 Feb 2017 00:52:09 +0000 (13:52 +1300)]
powerpc: Move THREAD_SHIFT config to Kconfig

Shift the logic for defining THREAD_SHIFT logic to Kconfig in order to
allow override by users.

Signed-off-by: Hamish Martin <hamish.martin@alliedtelesis.co.nz>
Reviewed-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
7 years agoLinux 4.11-rc3 v4.11-rc3
Linus Torvalds [Mon, 20 Mar 2017 02:09:39 +0000 (19:09 -0700)]
Linux 4.11-rc3

7 years agomm/swap: don't BUG_ON() due to uninitialized swap slot cache
Linus Torvalds [Mon, 20 Mar 2017 02:00:47 +0000 (19:00 -0700)]
mm/swap: don't BUG_ON() due to uninitialized swap slot cache

This BUG_ON() triggered for me once at shutdown, and I don't see a
reason for the check.  The code correctly checks whether the swap slot
cache is usable or not, so an uninitialized swap slot cache is not
actually problematic afaik.

I've temporarily just switched the BUG_ON() to a WARN_ON_ONCE(), since
I'm not sure why that seemingly pointless check was there.  I suspect
the real fix is to just remove it entirely, but for now we'll warn about
it but not bring the machine down.

Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
7 years agoMerge tag 'powerpc-4.11-5' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc...
Linus Torvalds [Mon, 20 Mar 2017 01:49:28 +0000 (18:49 -0700)]
Merge tag 'powerpc-4.11-5' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

Pull more powerpc fixes from Michael Ellerman:
 "A couple of minor powerpc fixes for 4.11:

   - wire up statx() syscall

   - don't print a warning on memory hotplug when HPT resizing isn't
     available

  Thanks to: David Gibson, Chandan Rajendra"

* tag 'powerpc-4.11-5' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/pseries: Don't give a warning when HPT resizing isn't available
  powerpc: Wire up statx() syscall

7 years agoMerge branch 'parisc-4.11-2' of git://git.kernel.org/pub/scm/linux/kernel/git/deller...
Linus Torvalds [Mon, 20 Mar 2017 01:11:13 +0000 (18:11 -0700)]
Merge branch 'parisc-4.11-2' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux

Pull parisc fixes from Helge Deller:

 - Mikulas Patocka added support for R_PARISC_SECREL32 relocations in
   modules with CONFIG_MODVERSIONS.

 - Dave Anglin optimized the cache flushing for vmap ranges.

 - Arvind Yadav provided a fix for a potential NULL pointer dereference
   in the parisc perf code (and some code cleanups).

 - I wired up the new statx system call, fixed some compiler warnings
   with the access_ok() macro and fixed shutdown code to really halt a
   system at shutdown instead of crashing & rebooting.

* 'parisc-4.11-2' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux:
  parisc: Fix system shutdown halt
  parisc: perf: Fix potential NULL pointer dereference
  parisc: Avoid compiler warnings with access_ok()
  parisc: Wire up statx system call
  parisc: Optimize flush_kernel_vmap_range and invalidate_kernel_vmap_range
  parisc: support R_PARISC_SECREL32 relocation in modules

7 years agoMerge git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending
Linus Torvalds [Mon, 20 Mar 2017 01:06:31 +0000 (18:06 -0700)]
Merge git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending

Pull SCSI target fixes from Nicholas Bellinger:
 "The bulk of the changes are in qla2xxx target driver code to address
  various issues found during Cavium/QLogic's internal testing (stable
  CC's included), along with a few other stability and smaller
  miscellaneous improvements.

  There are also a couple of different patch sets from Mike Christie,
  which have been a result of his work to use target-core ALUA logic
  together with tcm-user backend driver.

  Finally, a patch to address some long standing issues with
  pass-through SCSI export of TYPE_TAPE + TYPE_MEDIUM_CHANGER devices,
  which will make folks using physical (or virtual) magnetic tape happy"

* git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending: (28 commits)
  qla2xxx: Update driver version to 9.00.00.00-k
  qla2xxx: Fix delayed response to command for loop mode/direct connect.
  qla2xxx: Change scsi host lookup method.
  qla2xxx: Add DebugFS node to display Port Database
  qla2xxx: Use IOCB interface to submit non-critical MBX.
  qla2xxx: Add async new target notification
  qla2xxx: Export DIF stats via debugfs
  qla2xxx: Improve T10-DIF/PI handling in driver.
  qla2xxx: Allow relogin to proceed if remote login did not finish
  qla2xxx: Fix sess_lock & hardware_lock lock order problem.
  qla2xxx: Fix inadequate lock protection for ABTS.
  qla2xxx: Fix request queue corruption.
  qla2xxx: Fix memory leak for abts processing
  qla2xxx: Allow vref count to timeout on vport delete.
  tcmu: Convert cmd_time_out into backend device attribute
  tcmu: make cmd timeout configurable
  tcmu: add helper to check if dev was configured
  target: fix race during implicit transition work flushes
  target: allow userspace to set state to transitioning
  target: fix ALUA transition timeout handling
  ...

7 years agoMerge branch 'libnvdimm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdim...
Linus Torvalds [Sun, 19 Mar 2017 22:45:02 +0000 (15:45 -0700)]
Merge branch 'libnvdimm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm

Pull device-dax fixes from Dan Williams:
 "The device-dax driver was not being careful to handle falling back to
  smaller fault-granularity sizes.

  The driver already fails fault attempts that are smaller than the
  device's alignment, but it also needs to handle the cases where a
  larger page mapping could be established. For simplicity of the
  immediate fix the implementation just signals VM_FAULT_FALLBACK until
  fault-size == device-alignment.

  One fix is for -stable to address pmd-to-pte fallback from the
  original implementation, another fix is for the new (introduced in
  4.11-rc1) pud-to-pmd regression, and a typo fix comes along for the
  ride.

  These have received a build success notification from the kbuild
  robot"

* 'libnvdimm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
  device-dax: fix debug output typo
  device-dax: fix pud fault fallback handling
  device-dax: fix pmd/pte fault fallback handling

7 years agoqla2xxx: Update driver version to 9.00.00.00-k
Himanshu Madhani [Wed, 15 Mar 2017 16:48:56 +0000 (09:48 -0700)]
qla2xxx: Update driver version to 9.00.00.00-k

Signed-off-by: Himanshu Madhani <himanshu.madhani@cavium.com>
signed-off-by: Giridhar Malavali <giridhar.malavali@cavium.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
7 years agoqla2xxx: Fix delayed response to command for loop mode/direct connect.
Quinn Tran [Wed, 15 Mar 2017 16:48:55 +0000 (09:48 -0700)]
qla2xxx: Fix delayed response to command for loop mode/direct connect.

Current driver wait for FW to be in the ready state before
processing in-coming commands. For Arbitrated Loop or
Point-to- Point (not switch), FW Ready state can take a while.
FW will transition to ready state after all Nports have been
logged in. In the mean time, certain initiators have completed
the login and starts IO. Driver needs to start processing all
queues if FW is already started.

Signed-off-by: Quinn Tran <quinn.tran@cavium.com>
Signed-off-by: Himanshu Madhani <himanshu.madhani@cavium.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
7 years agoqla2xxx: Change scsi host lookup method.
Quinn Tran [Wed, 15 Mar 2017 16:48:54 +0000 (09:48 -0700)]
qla2xxx: Change scsi host lookup method.

For target mode, when new scsi command arrive, driver first performs
a look up of the SCSI Host. The current look up method is based on
the ALPA portion of the NPort ID. For Cisco switch, the ALPA can
not be used as the index. Instead, the new search method is based
on the full value of the Nport_ID via btree lib.

Signed-off-by: Quinn Tran <quinn.tran@cavium.com>
Signed-off-by: Himanshu Madhani <himanshu.madhani@cavium.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
7 years agoqla2xxx: Add DebugFS node to display Port Database
Himanshu Madhani [Wed, 15 Mar 2017 16:48:53 +0000 (09:48 -0700)]
qla2xxx: Add DebugFS node to display Port Database

Signed-off-by: Himanshu Madhani <himanshu.madhani@cavium.com>
Signed-off-by: Giridhar Malavali <giridhar.malavali@cavium.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
7 years agoqla2xxx: Use IOCB interface to submit non-critical MBX.
Quinn Tran [Wed, 15 Mar 2017 16:48:52 +0000 (09:48 -0700)]
qla2xxx: Use IOCB interface to submit non-critical MBX.

The Mailbox interface is currently over subscribed. We like
to reserve the Mailbox interface for the chip managment and
link initialization. Any non essential Mailbox command will
be routed through the IOCB interface. The IOCB interface is
able to absorb more commands.

Following commands are being routed through IOCB interface

- Get ID List (007Ch)
- Get Port DB (0064h)
- Get Link Priv Stats (006Dh)

Signed-off-by: Quinn Tran <quinn.tran@cavium.com>
Signed-off-by: Himanshu Madhani <himanshu.madhani@cavium.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
7 years agoqla2xxx: Add async new target notification
Quinn Tran [Wed, 15 Mar 2017 16:48:51 +0000 (09:48 -0700)]
qla2xxx: Add async new target notification

Signed-off-by: Quinn Tran <quinn.tran@cavium.com>
Signed-off-by: Himanshu Madhani <himanshu.madhani@cavium.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
7 years agoqla2xxx: Export DIF stats via debugfs
Anil Gurumurthy [Wed, 15 Mar 2017 16:48:50 +0000 (09:48 -0700)]
qla2xxx: Export DIF stats via debugfs

Signed-off-by: Anil Gurumurthy <anil.gurumurthy@cavium.com>
Signed-off-by: Himanshu Madhani <himanshu.madhani@cavium.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
7 years agoqla2xxx: Improve T10-DIF/PI handling in driver.
Quinn Tran [Wed, 15 Mar 2017 16:48:49 +0000 (09:48 -0700)]
qla2xxx: Improve T10-DIF/PI handling in driver.

Add routines to support T10 DIF tag.

Signed-off-by: Quinn Tran <quinn.tran@cavium.com>
Signed-off-by: Anil Gurumurthy <anil.gurumurthy@cavium.com>
Signed-off-by: Himanshu Madhani <himanshu.madhani@cavium.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
7 years agoqla2xxx: Allow relogin to proceed if remote login did not finish
Quinn Tran [Wed, 15 Mar 2017 16:48:48 +0000 (09:48 -0700)]
qla2xxx: Allow relogin to proceed if remote login did not finish

If the remote port have started the login process, then the
PLOGI and PRLI should be back to back. Driver will allow
the remote port to complete the process. For the case where
the remote port decide to back off from sending PRLI, this
local port sets an expiration timer for the PRLI. Once the
expiration time passes, the relogin retry logic is allowed
to go through and perform login with the remote port.

Signed-off-by: Quinn Tran <quinn.tran@qlogic.com>
Signed-off-by: Himanshu Madhani <himanshu.madhani@cavium.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
7 years agoqla2xxx: Fix sess_lock & hardware_lock lock order problem.
Quinn Tran [Wed, 15 Mar 2017 16:48:47 +0000 (09:48 -0700)]
qla2xxx: Fix sess_lock & hardware_lock lock order problem.

The main lock that needs to be held for CMD or TMR submission
to upper layer is the sess_lock. The sess_lock is used to
serialize cmd submission and session deletion. The addition
of hardware_lock being held is not necessary. This patch removes
hardware_lock dependency from CMD/TMR submission.

Use hardware_lock only for error response in this case.

Path1
       CPU0                    CPU1
       ----                    ----
  lock(&(&ha->tgt.sess_lock)->rlock);
                               lock(&(&ha->hardware_lock)->rlock);
                               lock(&(&ha->tgt.sess_lock)->rlock);
  lock(&(&ha->hardware_lock)->rlock);

Path2/deadlock
*** DEADLOCK ***
Call Trace:
dump_stack+0x85/0xc2
print_circular_bug+0x1e3/0x250
__lock_acquire+0x1425/0x1620
lock_acquire+0xbf/0x210
_raw_spin_lock_irqsave+0x53/0x70
qlt_sess_work_fn+0x21d/0x480 [qla2xxx]
process_one_work+0x1f4/0x6e0

Cc: <stable@vger.kernel.org>
Cc: Bart Van Assche <Bart.VanAssche@sandisk.com>
Reported-by: Bart Van Assche <Bart.VanAssche@sandisk.com>
Signed-off-by: Quinn Tran <quinn.tran@cavium.com>
Signed-off-by: Himanshu Madhani <himanshu.madhani@cavium.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
7 years agoqla2xxx: Fix inadequate lock protection for ABTS.
Quinn Tran [Wed, 15 Mar 2017 16:48:46 +0000 (09:48 -0700)]
qla2xxx: Fix inadequate lock protection for ABTS.

Normally, ABTS is sent to Target Core as Task MGMT command.
In the case of error, qla2xxx needs to send response, hardware_lock
is required to prevent request queue corruption.

Cc: <stable@vger.kernel.org>
Signed-off-by: Quinn Tran <quinn.tran@cavium.com>
Signed-off-by: Himanshu Madhani <himanshu.madhani@cavium.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
7 years agoqla2xxx: Fix request queue corruption.
Quinn Tran [Wed, 15 Mar 2017 16:48:45 +0000 (09:48 -0700)]
qla2xxx: Fix request queue corruption.

When FW notify driver or driver detects low FW resource,
driver tries to send out Busy SCSI Status to tell Initiator
side to back off. During the send process, the lock was not held.

Cc: <stable@vger.kernel.org>
Signed-off-by: Quinn Tran <quinn.tran@qlogic.com>
Signed-off-by: Himanshu Madhani <himanshu.madhani@cavium.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
7 years agoqla2xxx: Fix memory leak for abts processing
Quinn Tran [Wed, 15 Mar 2017 16:48:44 +0000 (09:48 -0700)]
qla2xxx: Fix memory leak for abts processing

Cc: <stable@vger.kernel.org>
Signed-off-by: Quinn Tran <quinn.tran@cavium.com>
Signed-off-by: Himanshu Madhani <himanshu.madhani@cavium.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
7 years agoqla2xxx: Allow vref count to timeout on vport delete.
Joe Carnuccio [Wed, 15 Mar 2017 16:48:43 +0000 (09:48 -0700)]
qla2xxx: Allow vref count to timeout on vport delete.

Cc: <stable@vger.kernel.org>
Signed-off-by: Joe Carnuccio <joe.carnuccio@cavium.com>
Signed-off-by: Himanshu Madhani <himanshu.madhani@cavium.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
7 years agotcmu: Convert cmd_time_out into backend device attribute
Nicholas Bellinger [Sat, 18 Mar 2017 22:04:13 +0000 (15:04 -0700)]
tcmu: Convert cmd_time_out into backend device attribute

Instead of putting cmd_time_out under ../target/core/user_0/foo/control,
which has historically been used by parameters needed for initial
backend device configuration, go ahead and move cmd_time_out into
a backend device attribute.

In order to do this, tcmu_module_init() has been updated to create
a local struct configfs_attribute **tcmu_attrs, that is based upon
the existing passthrough_attrib_attrs along with the new cmd_time_out
attribute.  Once **tcm_attrs has been setup, go ahead and point
it at tcmu_ops->tb_dev_attrib_attrs so it's picked up by target-core.

Also following MNC's previous change, ->cmd_time_out is stored in
milliseconds but exposed via configfs in seconds.  Also, note this
patch restricts the modification of ->cmd_time_out to before +
after the TCMU device has been configured, but not while it has
active fabric exports.

Cc: Mike Christie <mchristi@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
7 years agotcmu: make cmd timeout configurable
Mike Christie [Thu, 9 Mar 2017 08:42:09 +0000 (02:42 -0600)]
tcmu: make cmd timeout configurable

A single daemon could implement multiple types of devices
using multuple types of real devices that may not support
restarting from crashes and/or handling tcmu timeouts. This
makes the cmd timeout configurable, so handlers that do not
support it can turn if off for now.

Signed-off-by: Mike Christie <mchristi@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
7 years agotcmu: add helper to check if dev was configured
Mike Christie [Thu, 9 Mar 2017 08:42:08 +0000 (02:42 -0600)]
tcmu: add helper to check if dev was configured

This adds a helper to check if the dev was configured. It
will be used in the next patch to prevent updates to some
config settings after the device has been setup.

Signed-off-by: Mike Christie <mchristi@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
7 years agoMerge tag 'openrisc-for-linus' of git://github.com/openrisc/linux
Linus Torvalds [Sat, 18 Mar 2017 22:50:39 +0000 (15:50 -0700)]
Merge tag 'openrisc-for-linus' of git://github.com/openrisc/linux

Pull OpenRISC fixes from Stafford Horne:
 "OpenRISC fixes for build issues that were exposed by kbuild robots
  after 4.11 merge. All from allmodconfig builds. This includes:

   - bug in the handling of 8-byte get_user() calls

   - module build failure due to multile missing symbol exports"

* tag 'openrisc-for-linus' of git://github.com/openrisc/linux:
  openrisc: Export symbols needed by modules
  openrisc: fix issue handling 8 byte get_user calls
  openrisc: xchg: fix `computed is not used` warning

7 years agotarget: fix race during implicit transition work flushes
Mike Christie [Thu, 2 Mar 2017 10:59:50 +0000 (04:59 -0600)]
target: fix race during implicit transition work flushes

This fixes the following races:

1. core_alua_do_transition_tg_pt could have read
tg_pt_gp_alua_access_state and gone into this if chunk:

if (!explicit &&
        atomic_read(&tg_pt_gp->tg_pt_gp_alua_access_state) ==
           ALUA_ACCESS_STATE_TRANSITION) {

and then core_alua_do_transition_tg_pt_work could update the
state. core_alua_do_transition_tg_pt would then only set
tg_pt_gp_alua_pending_state and the tg_pt_gp_alua_access_state would
not get updated with the second calls state.

2. core_alua_do_transition_tg_pt could be setting
tg_pt_gp_transition_complete while the tg_pt_gp_transition_work
is already completing. core_alua_do_transition_tg_pt then waits on the
completion that will never be called.

To handle these issues, we just call flush_work which will return when
core_alua_do_transition_tg_pt_work has completed so there is no need
to do the complete/wait. And, if core_alua_do_transition_tg_pt_work
was running, instead of trying to sneak in the state change, we just
schedule up another core_alua_do_transition_tg_pt_work call.

Note that this does not handle a possible race where there are multiple
threads call core_alua_do_transition_tg_pt at the same time. I think
we need a mutex in target_tg_pt_gp_alua_access_state_store.

Signed-off-by: Mike Christie <mchristi@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>