So far the IOC treatment was global on ARC, being turned on (or off)
for all devices in the system. With this patch, this can now be done
per device using the "dma-coherent" DT property; IOW with this patch
we can use both HW-coherent and regular DMA peripherals simultaneously.

The changes involved are too many so enlisting the summary below:

1. common code calls ARC arch_setup_dma_ops() per device.

2. For coherent dma (IOC) it plugs in generic @dma_direct_ops which
   doesn't need any arch specific backend: No need for any explicit
   cache flushes or MMU mappings to provide for uncached access

   - dma_(map|sync)_single* return early as corresponding dma ops callbacks
     are NULL in generic code.
     So arch_sync_dma_*() -> dma_cache_*() need not handle the coherent
     dma case, hence drop ARC __dma_cache_*_ioc() which were no-op anyways

3. For noncoherent dma (non IOC) generic @dma_noncoherent_ops is used
   which in turns calls ARC specific routines

   - arch_dma_alloc() no longer checks for @ioc_enable since this is
     called only for !IOC case.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
[vgupta: rewrote changelog]

In 4.19-rc1, Eugeniy reported weird boot and IO errors on ARC HSDK

| INFO: task syslogd:77 blocked for more than 10 seconds.
|       Not tainted 4.19.0-rc1-00007-gf213acea4e88 #40
| "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this
| message.
| syslogd         D    0    77     76 0x00000000
|
| Stack Trace:
|  __switch_to+0x0/0xac
|  __schedule+0x1b2/0x730
|  io_schedule+0x5c/0xc0
|  __lock_page+0x98/0xdc
|  find_lock_entry+0x38/0x100
|  shmem_getpage_gfp.isra.3+0x82/0xbfc
|  shmem_fault+0x46/0x138
|  handle_mm_fault+0x5bc/0x924
|  do_page_fault+0x100/0x2b8
|  ret_from_exception+0x0/0x8

He bisected to 84c6591103db ("locking/atomics,
asm-generic/bitops/lock.h: Rewrite using atomic_fetch_*()")

This commit however only unmasked the real issue introduced by commit
4aef66c8ae9 ("locking/atomic, arch/arc: Fix build") which missed the
retry-if-scond-failed branch in atomic_fetch_##op() macros.

The bisected commit started using atomic_fetch_##op() macros for building
the rest of atomics.

Fixes: 4aef66c8ae9 ("locking/atomic, arch/arc: Fix build")
Reported-by: Eugeniy Paltsev <paltsev@synopsys.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
[vgupta: wrote changelog]

Pull perf update from Thomas Gleixner:
 "The perf crowd presents:

  Kernel updates:

   - Removal of jprobes

   - Cleanup and consolidatation the handling of kprobes

   - Cleanup and consolidation of hardware breakpoints

   - The usual pile of fixes and updates to PMUs and event descriptors

  Tooling updates:

   - Updates and improvements all over the place. Nothing outstanding,
     just the (good) boring incremental grump work"

* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (103 commits)
  perf trace: Do not require --no-syscalls to suppress strace like output
  perf bpf: Include uapi/linux/bpf.h from the 'perf trace' script's bpf.h
  perf tools: Allow overriding MAX_NR_CPUS at compile time
  perf bpf: Show better message when failing to load an object
  perf list: Unify metric group description format with PMU event description
  perf vendor events arm64: Update ThunderX2 implementation defined pmu core events
  perf cs-etm: Generate branch sample for CS_ETM_TRACE_ON packet
  perf cs-etm: Generate branch sample when receiving a CS_ETM_TRACE_ON packet
  perf cs-etm: Support dummy address value for CS_ETM_TRACE_ON packet
  perf cs-etm: Fix start tracing packet handling
  perf build: Fix installation directory for eBPF
  perf c2c report: Fix crash for empty browser
  perf tests: Fix indexing when invoking subtests
  perf trace: Beautify the AF_INET & AF_INET6 'socket' syscall 'protocol' args
  perf trace beauty: Add beautifiers for 'socket''s 'protocol' arg
  perf trace beauty: Do not print NULL strarray entries
  perf beauty: Add a generator for IPPROTO_ socket's protocol constants
  tools include uapi: Grab a copy of linux/in.h
  perf tests: Fix complex event name parsing
  perf evlist: Fix error out while applying initial delay and LBR
  ...

Pull locking/atomics update from Thomas Gleixner:
 "The locking, atomics and memory model brains delivered:

   - A larger update to the atomics code which reworks the ordering
     barriers, consolidates the atomic primitives, provides the new
     atomic64_fetch_add_unless() primitive and cleans up the include
     hell.

   - Simplify cmpxchg() instrumentation and add instrumentation for
     xchg() and cmpxchg_double().

   - Updates to the memory model and documentation"

* 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (48 commits)
  locking/atomics: Rework ordering barriers
  locking/atomics: Instrument cmpxchg_double*()
  locking/atomics: Instrument xchg()
  locking/atomics: Simplify cmpxchg() instrumentation
  locking/atomics/x86: Reduce arch_cmpxchg64*() instrumentation
  tools/memory-model: Rename litmus tests to comply to norm7
  tools/memory-model/Documentation: Fix typo, smb->smp
  sched/Documentation: Update wake_up() & co. memory-barrier guarantees
  locking/spinlock, sched/core: Clarify requirements for smp_mb__after_spinlock()
  sched/core: Use smp_mb() in wake_woken_function()
  tools/memory-model: Add informal LKMM documentation to MAINTAINERS
  locking/atomics/Documentation: Describe atomic_set() as a write operation
  tools/memory-model: Make scripts executable
  tools/memory-model: Remove ACCESS_ONCE() from model
  tools/memory-model: Remove ACCESS_ONCE() from recipes
  locking/memory-barriers.txt/kokr: Update Korean translation to fix broken DMA vs. MMIO ordering example
  MAINTAINERS: Add Daniel Lustig as an LKMM reviewer
  tools/memory-model: Fix ISA2+pooncelock+pooncelock+pombonce name
  tools/memory-model: Add litmus test for full multicopy atomicity
  locking/refcount: Always allow checked forms
  ...

Fix build errors in arch/arc/'s delay.h:
- add "extern unsigned long loops_per_jiffy;"
- add <asm-generic/types.h> for "u64"

In file included from ../drivers/infiniband/hw/cxgb3/cxio_hal.c:32:
../arch/arc/include/asm/delay.h: In function '__udelay':
../arch/arc/include/asm/delay.h:61:12: error: 'u64' undeclared (first use in this function)
  loops = ((u64) usecs * 4295 * HZ * loops_per_jiffy) >> 32;
            ^~~

In file included from ../drivers/infiniband/hw/cxgb3/cxio_hal.c:32:
../arch/arc/include/asm/delay.h: In function '__udelay':
../arch/arc/include/asm/delay.h:63:37: error: 'loops_per_jiffy' undeclared (first use in this function)
  loops = ((u64) usecs * 4295 * HZ * loops_per_jiffy) >> 32;
                                     ^~~~~~~~~~~~~~~

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: linux-snps-arc@lists.infradead.org
Cc: Elad Kanfi <eladkan@mellanox.com>
Cc: Leon Romanovsky <leonro@mellanox.com>
Cc: Ofer Levi <oferle@mellanox.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>

As for today we don't setup SMP_CACHE_BYTES and cache_line_size for
ARC, so they are set to L1_CACHE_BYTES by default. L1 line length
(L1_CACHE_BYTES) might be easily smaller than L2 line (which is
usually the case BTW). This breaks code.

For example this breaks ethernet infrastructure on HSDK/AXS103 boards
with IOC disabled, involving manual cache flushes
Functions which alloc and manage sk_buff packet data area rely on
SMP_CACHE_BYTES define. In the result we can share last L2 cache
line in sk_buff linear packet data area between DMA buffer and
some useful data in other structure. So we can lose this data when
we invalidate DMA buffer.

   sk_buff linear packet data area
                |
                |
                |         skb->end        skb->tail
                V            |                |
                             V                V
----------------------------------------------.
      packet data            | <tail padding> |  <useful data in other struct>
----------------------------------------------.

---------------------.--------------------------------------------------.
     SLC line        |             SLC (L2 cache) line (128B)           |
---------------------.--------------------------------------------------.
        ^                                     ^
        |                                     |
     These cache lines will be invalidated when we invalidate skb
     linear packet data area before DMA transaction starting.

This leads to issues painful to debug as it reproduces only if
(sk_buff->end - sk_buff->tail) < SLC_LINE_SIZE and
if we have some useful data right after sk_buff->end.

Fix that by hardcode SMP_CACHE_BYTES to max line length we may have.

Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>

Signed-off-by: Ingo Molnar <mingo@kernel.org>

Pull ARC fixes from Vineet Gupta:
 "ARC is back after radio silence in 4.17:

   - Fix CONFIG_SWAP [Alexey]

   - Robustify cmpxchg emulation for systems w/o atomics [Alexey /
     PeterZ]

   - Allow mprotext(PROT_EXEC) for stack mappings [Vineet]

   - HSDK platform enable PCIe, APG GPIO [Gustavo]

   - miscll other fixes, config updates etc"

* tag 'arc-4.18-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc:
  ARCv2: [plat-hsdk]: Save accl reg pair by default
  ARC: mm: allow mprotect to make stack mappings executable
  ARC: Fix CONFIG_SWAP
  ARC: [arcompact] entry.S: minor code movement
  ARC: configs: Remove CONFIG_INITRAMFS_SOURCE from defconfigs
  ARC: configs: remove no longer needed CONFIG_DEVPTS_MULTIPLE_INSTANCES
  ARC: Improve cmpxchg syscall implementation
  ARC: [plat-hsdk]: Configure APB GPIO controller on ARC HSDK platform
  ARC: [plat-hsdk] Add PCIe support
  ARC: Enable machine_desc->init_per_cpu for !CONFIG_SMP
  ARC: Explicitly add -mmedium-calls to CFLAGS

mprotect(EXEC) was failing for stack mappings as default vm flags was
missing MAYEXEC.

This was triggered by glibc test suite nptl/tst-execstack testcase

What is surprising is that despite running LTP for years on, we didn't
catch this issue as it lacks a directed test case.

gcc dejagnu tests with nested functions also requiring exec stack work
fine though because they rely on the GNU_STACK segment spit out by
compiler and handled in kernel elf loader.

This glibc case is different as the stack is non exec to begin with and
a dlopen of shared lib with GNU_STACK segment triggers the exec stack
proceedings using a mprotect(PROT_EXEC) which was broken.

CC: stable@vger.kernel.org
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>

swap was broken on ARC due to silly copy-paste issue.

We encode offset from swapcache page in __swp_entry() as (off << 13) but
were not decoding back in __swp_offset() as (off >> 13) - it was still
(off << 13).

This finally fixes swap usage on ARC.

| # mkswap /dev/sda2
|
| # swapon -a -e /dev/sda2
| Adding 500728k swap on /dev/sda2.  Priority:-2 extents:1 across:500728k
|
| # free
|              total       used       free     shared    buffers     cached
| Mem:        765104      13456     751648       4736          8       4736
| -/+ buffers/cache:       8712     756392
| Swap:       500728          0     500728

Cc: stable@vger.kernel.org
Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>