This patch updates the parisc huge TLB page support to use per-pagetable spinlocks.

This patch requires Mikulas' per-pagetable spinlock patch and the revised TLB
serialization patch from Helge and myself.  With Mikulas' patch, we need to use
the per-pagetable spinlock for page table updates.  The TLB lock is only used
to serialize TLB flushes on machines with the Merced bus.
Signed-off-by: John David Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>

PA-RISC uses a global spinlock to protect pagetable updates in the TLB
fault handlers. When multiple cores are taking TLB faults simultaneously,
the cache line containing the spinlock becomes a bottleneck.

This patch embeds the spinlock in the top level page directory, so that
every process has its own lock. It improves performance by 30% when
doing parallel compilations.

At least on the N class systems, only one PxTLB inter processor
broadcast can be active at any one time on the Merced bus. If a Merced
bus is found, this patch serializes the TLB flushes with the
pa_tlb_flush_lock spinlock.

v1: Initial patch by Mikulas
v2: Added Merced detection by Helge
v3: Revised TLB serialization by Dave & Helge
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: John David Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>

When making the text sections writeable with set_kernel_text_rw(1),
include all text sections including those in the __init section.
Otherwise functions marked with __meminit will stay read-only.
Signed-off-by: Helge Deller <deller@gmx.de>
Cc: <stable@vger.kernel.org>	# 4.20+

Add compiler memory barriers to ensure the compiler doesn't reorder memory
operations around these instructions.

Cc: stable@vger.kernel.org # v4.20+
Fixes: 3847dab7 ("parisc: Add alternative coding infrastructure")
Signed-off-by: Helge Deller <deller@gmx.de>

The pdtlb and pitlb instructions are strongly ordered. The asms invoking
these instructions should be compiler memory barriers to ensure the
compiler doesn't reorder memory operations around these instructions.
Signed-off-by: John David Anglin <dave.anglin@bell.net>
CC: stable@vger.kernel.org # v4.20+
Fixes: 3847dab7 ("parisc: Add alternative coding infrastructure")
Signed-off-by: Helge Deller <deller@gmx.de>

There are only a couple of instructions that can function as a memory
barrier on parisc.  Currently, we use the sync instruction as a memory
barrier when releasing a spinlock.  However, the ldcw instruction is a
better barrier when we have a handy memory location since it operates in
the cache on coherent machines.

This patch updates the spinlock release code to use ldcw.  I also
changed the "stw,ma" instructions to "stw" instructions as it is not an
adequate barrier.
Signed-off-by: John David Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>

TLB operations only need to be serialized on machines with the Merced
(Stretch) bus. The only machines in this category are L and N class, and
they require a 64-bit PA 2.0 kernel. On these machines, we use local TLB
purges in the tmpalias routines.
We don't need to serialize TLB purges on all other machines. Thus, the
lock/unlock code can be removed when CONFIG_PA20 is not defined.
Further, when CONFIG_PA20 is not defined, alternative patching converts
the TLB purges to local purges when PA 2.0 hardware has been detected.
Signed-off-by: John David Anglin <dave.anglin@bell.net>
Tested-By: Sven Schnelle <svens@stackframe.org>
Signed-off-by: Helge Deller <deller@gmx.de>

The commit 1c30844d ("mm: reclaim small amounts of memory when an
external fragmentation event occurs") breaks memory management on a
parisc c8000 workstation with this memory layout:

	0) Start 0x0000000000000000 End 0x000000003fffffff Size   1024 MB
	1) Start 0x0000000100000000 End 0x00000001bfdfffff Size   3070 MB
	2) Start 0x0000004040000000 End 0x00000040ffffffff Size   3072 MB

With the patch 1c30844d, the kernel will incorrectly reclaim the
first zone when it fills up, ignoring the fact that there are two
completely free zones. Basiscally, it limits cache size to 1GiB.

The parisc kernel is currently using the DISCONTIGMEM implementation,
but isn't NUMA. Avoid this issue or strange work-arounds by switching to
the more commonly used SPARSEMEM implementation.
Reported-by: Mikulas Patocka <mpatocka@redhat.com>
Fixes: 1c30844d ("mm: reclaim small amounts of memory when an external fragmentation event occurs")
Signed-off-by: Helge Deller <deller@gmx.de>

The idle task might have been allocated above 4GB. With the current code
we cannot access that memory because the CPU is still running in narrow
mode.
This was found on a J5000 machine and the patch is required to enable
SPARSEMEM on that machine.
Signed-off-by: Sven Schnelle <svens@stackframe.org>
Signed-off-by: Helge Deller <deller@gmx.de>

Update lists to reflect that we have now KGDB and kretprobes
support.
Signed-off-by: Sven Schnelle <svens@stackframe.org>
Signed-off-by: Helge Deller <deller@gmx.de>

Signed-off-by: Helge Deller <deller@gmx.de>

It's not used by patch_map()/patch_unmap(), so lets remove
it.
Signed-off-by: Sven Schnelle <svens@stackframe.org>
Signed-off-by: Helge Deller <deller@gmx.de>

Now that kprobes and kretprobes are implemented, update the list in
Documentation to reflect that.
Signed-off-by: Sven Schnelle <svens@stackframe.org>
Signed-off-by: Helge Deller <deller@gmx.de>

Implement kretprobes on parisc, parts stolen from powerpc.
Signed-off-by: Sven Schnelle <svens@stackframe.org>
Signed-off-by: Helge Deller <deller@gmx.de>

We're providing our own version now.
Signed-off-by: Sven Schnelle <svens@stackframe.org>
Signed-off-by: Helge Deller <deller@gmx.de>

Implement kprobes support for PA-RISC.
Signed-off-by: Sven Schnelle <svens@stackframe.org>
Signed-off-by: Helge Deller <deller@gmx.de>

implement regs_get_register(), regs_get_kernel_stack_nth() and
regs_within_kernel_stack()
Signed-off-by: Sven Schnelle <svens@stackframe.org>
Signed-off-by: Helge Deller <deller@gmx.de>

Even a 32-bit kernel requires at least 27 MB to decompress itself, so
halt the system with a message if the system has less memory than 32 MB.
Signed-off-by: Helge Deller <deller@gmx.de>

No need to spend CPU cycles when we run on QEMU.
Signed-off-by: Helge Deller <deller@gmx.de>
CC: stable@vger.kernel.org # v4.9+

Do not loose cycles when we run on QEMU, and fix one trivial typo.
Signed-off-by: Helge Deller <deller@gmx.de>

Signed-off-by: Helge Deller <deller@gmx.de>
CC: stable@vger.kernel.org # v4.9+

This patch add KGDB support to PA-RISC. It also implements
single-stepping utilizing the recovery counter.
Signed-off-by: Sven Schnelle <svens@stackframe.org>
Signed-off-by: Helge Deller <deller@gmx.de>

Instead of re-mapping the whole kernel text with RWX rights
add a patch_text() which can be used to replace instructions
in the kernel .text section. Based on the ARM implementation.
Signed-off-by: Sven Schnelle <svens@stackframe.org>
Signed-off-by: Helge Deller <deller@gmx.de>

These functions will be used for adding code patching
functions later.
Signed-off-by: Sven Schnelle <svens@stackframe.org>
Signed-off-by: Helge Deller <deller@gmx.de>

Do not offset mmap base address because of stack randomization if
current task does not want randomization.
Signed-off-by: Alexandre Ghiti <alex@ghiti.fr>
Signed-off-by: Helge Deller <deller@gmx.de>

Pull ARM fixes from Russell King:
 "A small number of ARM fixes

   - Fix function tracer and unwinder dependencies so that we don't end
     up building kernels that will crash

   - Fix ARMv7M nommu initialisation (missing register initialisation)

   - Fix EFI decompressor entry (ensuring barrier instructions are
     enabled prior to use)"

* tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm:
  ARM: 8857/1: efi: enable CP15 DMB instructions before cleaning the cache
  ARM: 8856/1: NOMMU: Fix CCR register faulty initialization when MPU is disabled
  ARM: fix function graph tracer and unwinder dependencies

Pull powerpc fixes from Michael Ellerman:
 "A one-liner to make our Radix MMU support depend on HUGETLB_PAGE. We
  use some of the hugetlb inlines (eg. pud_huge()) when operating on the
  linear mapping and if they're compiled into empty wrappers we can
  corrupt memory.

  Then two fixes to our VFIO IOMMU code. The first is not a regression
  but fixes the locking to avoid a user-triggerable deadlock.

  The second does fix a regression since rc1, and depends on the first
  fix. It makes it possible to run guests with large amounts of memory
  again (~256GB).

  Thanks to Alexey Kardashevskiy"

* tag 'powerpc-5.1-6' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/mm_iommu: Allow pinning large regions
  powerpc/mm_iommu: Fix potential deadlock
  powerpc/mm/radix: Make Radix require HUGETLB_PAGE

Pull block fixes from Jens Axboe:
 "A set of io_uring fixes that should go into this release. In
  particular, this contains:

   - The mutex lock vs ctx ref count fix (me)

   - Removal of a dead variable (me)

   - Two race fixes (Stefan)

   - Ring head/tail condition fix for poll full SQ detection (Stefan)"

* tag 'for-linus-20190428' of git://git.kernel.dk/linux-block:
  io_uring: remove 'state' argument from io_{read,write} path
  io_uring: fix poll full SQ detection
  io_uring: fix race condition when sq threads goes sleeping
  io_uring: fix race condition reading SQ entries
  io_uring: fail io_uring_register(2) on a dying io_uring instance

Pull rdma fixes from Jason Gunthorpe:
 "One core bug fix and a few driver ones

   - FRWR memory registration for hfi1/qib didn't work with with some
     iovas causing a NFSoRDMA failure regression due to a fix in the NFS
     side

   - A command flow error in mlx5 allowed user space to send a corrupt
     command (and also smash the kernel stack we've since learned)

   - Fix a regression and some bugs with device hot unplug that was
     discovered while reviewing Andrea's patches

   - hns has a failure if the user asks for certain QP configurations"

* tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma:
  RDMA/hns: Bugfix for mapping user db
  RDMA/ucontext: Fix regression with disassociate
  RDMA/mlx5: Use rdma_user_map_io for mapping BAR pages
  RDMA/mlx5: Do not allow the user to write to the clock page
  IB/mlx5: Fix scatter to CQE in DCT QP creation
  IB/rdmavt: Fix frwr memory registration

Pull dmaengine fixes from Vinod Koul:

 - fix for wrong register use in mediatek driver

 - fix in sh driver for glitch is tx_status and treating 0 a valid
   residue for cyclic

 - fix in bcm driver for using right memory allocation flag

* tag 'dmaengine-fix-5.1-rc7' of git://git.infradead.org/users/vkoul/slave-dma:
  dmaengine: mediatek-cqdma: fix wrong register usage in mtk_cqdma_start
  dmaengine: sh: rcar-dmac: Fix glitch in dmaengine_tx_status
  dmaengine: sh: rcar-dmac: With cyclic DMA residue 0 is valid
  dmaengine: bcm2835: Avoid GFP_KERNEL in device_prep_slave_sg

Pull input fixes from Dmitry Torokhov:
 "Just a couple of fixups for Synaptics RMI4 driver and allowing
  snvs_pwrkey to be selected on more boards"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
  Input: synaptics-rmi4 - write config register values to the right offset
  Input: synaptics-rmi4 - fix possible double free
  Input: snvs_pwrkey - make it depend on ARCH_MXC

Pull x86 fixes from Ingo Molnar:

 - Fix an early boot crash in the RSDP parsing code by effectively
   turning off the parsing call - we ran out of time but want to fix the
   regression. The more involved fix is being worked on.

 - Fix a crash that can trigger in the kmemlek code.

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/mm: Fix a crash with kmemleak_scan()
  x86/boot: Disable RSDP parsing temporarily

Pull scheduler fix from Ingo Molnar:
 "Fix a division by zero bug that can trigger in the NUMA placement
  code"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/numa: Fix a possible divide-by-zero

Pull perf fix from Ingo Molnar:
 "A cstate event enumeration fix for Kaby/Coffee Lake CPUs"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/x86/intel: Update KBL Package C-state events to also include PC8/PC9/PC10 counters

This way, slhc_free() accepts what slhc_init() returns, whether that is
an error or not.

In particular, the pattern in sl_alloc_bufs() is

        slcomp = slhc_init(16, 16);
        ...
        slhc_free(slcomp);

for the error handling path, and rather than complicate that code, just
make it ok to always free what was returned by the init function.

That's what the code used to do before commit 4ab42d78 ("ppp, slip:
Validate VJ compression slot parameters completely") when slhc_init()
just returned NULL for the error case, with no actual indication of the
details of the error.

Reported-by: syzbot+45474c076a4927533d2e@syzkaller.appspotmail.com
Fixes: 4ab42d78 ("ppp, slip: Validate VJ compression slot parameters completely")
Acked-by: Ben Hutchings <ben@decadent.org.uk>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Merge misc fixes from Andrew Morton:
 "9 fixes"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  fs/proc/proc_sysctl.c: Fix a NULL pointer dereference
  mm/page_alloc.c: fix never set ALLOC_NOFRAGMENT flag
  mm/page_alloc.c: avoid potential NULL pointer dereference
  mm, page_alloc: always use a captured page regardless of compaction result
  mm: do not boost watermarks to avoid fragmentation for the DISCONTIG memory model
  lib/test_vmalloc.c: do not create cpumask_t variable on stack
  lib/Kconfig.debug: fix build error without CONFIG_BLOCK
  zram: pass down the bvec we need to read into in the work struct
  mm/memory_hotplug.c: drop memory device reference after find_memory_block()

Currently any changed config register values don't take effect, as the
function to write them back is called with the wrong register offset.

Fixes: ff8f8370 (Input: synaptics-rmi4 - add support for 2D
                     sensors and F11)
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
Cc: stable@vger.kernel.org
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Pull arm64 fixes from Catalin Marinas:

 - keep the tail of an unaligned initrd reserved

 - adjust ftrace_make_call() to deal with the relative nature of PLTs

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  arm64/module: ftrace: deal with place relative nature of PLTs
  arm64: mm: Ensure tail of unaligned initrd is reserved

Pull tracing fixes from Steven Rostedt:
 "Three tracing fixes:

   - Use "nosteal" for ring buffer splice pages

   - Memory leak fix in error path of trace_pid_write()

   - Fix preempt_enable_no_resched() (use preempt_enable()) in ring
     buffer code"

* tag 'trace-v5.1-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  trace: Fix preempt_enable_no_resched() abuse
  tracing: Fix a memory leak by early error exit in trace_pid_write()
  tracing: Fix buffer_ref pipe ops