linux.git/arch/arc/include/asm, branch v5.1

syscalls: Remove start and number from syscall_get_arguments() args

2019-04-05T13:26:43+00:00

At Linux Plumbers, Andy Lutomirski approached me and pointed out that the
function call syscall_get_arguments() implemented in x86 was horribly
written and not optimized for the standard case of passing in 0 and 6 for
the starting index and the number of system calls to get. When looking at
all the users of this function, I discovered that all instances pass in only
0 and 6 for these arguments. Instead of having this function handle
different cases that are never used, simply rewrite it to return the first 6
arguments of a system call.

This should help out the performance of tracing system calls by ptrace,
ftrace and perf.

Link: http://lkml.kernel.org/r/20161107213233.754809394@goodmis.org

Cc: Oleg Nesterov 
Cc: Kees Cook 
Cc: Andy Lutomirski 
Cc: Dominik Brodowski 
Cc: Dave Martin 
Cc: "Dmitry V. Levin" 
Cc: x86@kernel.org
Cc: linux-snps-arc@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-c6x-dev@linux-c6x.org
Cc: uclinux-h8-devel@lists.sourceforge.jp
Cc: linux-hexagon@vger.kernel.org
Cc: linux-ia64@vger.kernel.org
Cc: linux-mips@vger.kernel.org
Cc: nios2-dev@lists.rocketboards.org
Cc: openrisc@lists.librecores.org
Cc: linux-parisc@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-riscv@lists.infradead.org
Cc: linux-s390@vger.kernel.org
Cc: linux-sh@vger.kernel.org
Cc: sparclinux@vger.kernel.org
Cc: linux-um@lists.infradead.org
Cc: linux-xtensa@linux-xtensa.org
Cc: linux-arch@vger.kernel.org
Acked-by: Paul Burton  # MIPS parts
Acked-by: Max Filippov  # For xtensa changes
Acked-by: Will Deacon  # For the arm64 bits
Reviewed-by: Thomas Gleixner  # for x86
Reviewed-by: Dmitry V. Levin 
Reported-by: Andy Lutomirski 
Signed-off-by: Steven Rostedt (VMware)

KVM: export and iif KVM is supported

2019-03-28T16:27:42+00:00

I do not see any consistency about headers_install of 
and .

According to my analysis of Linux 5.1-rc1, there are 3 groups:

 [1] Both  and  are exported

    alpha, arm, hexagon, mips, powerpc, s390, sparc, x86

 [2]  is exported, but  is not

    arc, arm64, c6x, h8300, ia64, m68k, microblaze, nios2, openrisc,
    parisc, sh, unicore32, xtensa

 [3] Neither  nor  is exported

    csky, nds32, riscv

This does not match to the actual KVM support. At least, [2] is
half-baked.

Nor do arch maintainers look like they care about this. For example,
commit 0add53713b1c ("microblaze: Add missing kvm_para.h to Kbuild")
exported  to user-space in order to fix an in-kernel
build error.

We have two ways to make this consistent:

 [A] export both  and  for all
     architectures, irrespective of the KVM support

 [B] Match the header export of  and 
     to the KVM support

My first attempt was [A] because the code looks cleaner, but Paolo
suggested [B].

So, this commit goes with [B].

For most architectures,  was moved to the kernel-space.
I changed include/uapi/linux/Kbuild so that it checks generated
asm/kvm_para.h as well as check-in ones.

After this commit, there will be two groups:

 [1] Both  and  are exported

    arm, arm64, mips, powerpc, s390, x86

 [2] Neither  nor  is exported

    alpha, arc, c6x, csky, h8300, hexagon, ia64, m68k, microblaze,
    nds32, nios2, openrisc, parisc, riscv, sh, sparc, unicore32, xtensa

Signed-off-by: Masahiro Yamada 
Acked-by: Cornelia Huck 
Signed-off-by: Paolo Bonzini

Merge tag 'arc-5.1-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc

2019-03-20T18:01:52+00:00

Pull ARC updates from Vineet Gupta:

 - unaligned access support for HS cores

 - Removed extra memory barrier around spinlock code

 - HSDK platform updates: enable dmac, reset

 - some more boot logging updates

 - misc minor fixes

* tag 'arc-5.1-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc:
  arch: arc: Kconfig: pedantic formatting
  ARCv2: spinlock: remove the extra smp_mb before lock, after unlock
  ARC: unaligned: relax the check for gcc supporting -mno-unaligned-access
  ARC: boot log: cut down on verbosity
  ARCv2: boot log: refurbish HS core/release identification
  arc: hsdk_defconfig: Enable CONFIG_BLK_DEV_RAM
  ARC: u-boot args: check that magic number is correct
  ARC: perf: bpok condition only exists for ARCompact
  ARCv2: Add explcit unaligned access support (and ability to disable too)
  ARCv2: lib: introduce memcpy optimized for unaligned access
  ARC: [plat-hsdk]: Enable AXI DW DMAC support
  ARC: [plat-hsdk]: Add reset controller handle to manage USB reset
  ARC: DTB: [scripted] fix node name and address spelling

Merge tag 'dma-mapping-5.1' of git://git.infradead.org/users/hch/dma-mapping

2019-03-10T18:54:48+00:00

Pull DMA mapping updates from Christoph Hellwig:

 - add debugfs support for dumping dma-debug information (Corentin
   Labbe)

 - Kconfig cleanups (Andy Shevchenko and me)

 - debugfs cleanups (Greg Kroah-Hartman)

 - improve dma_map_resource and use it in the media code

 - arch_setup_dma_ops / arch_teardown_dma_ops cleanups

 - various small cleanups and improvements for the per-device coherent
   allocator

 - make the DMA mask an upper bound and don't fail "too large" dma mask
   in the remaning two architectures - this will allow big driver
   cleanups in the following merge windows

* tag 'dma-mapping-5.1' of git://git.infradead.org/users/hch/dma-mapping: (21 commits)
  Documentation/DMA-API-HOWTO: update dma_mask sections
  sparc64/pci_sun4v: allow large DMA masks
  sparc64/iommu: allow large DMA masks
  sparc64: refactor the ali DMA quirk
  ccio: allow large DMA masks
  dma-mapping: remove the DMA_MEMORY_EXCLUSIVE flag
  dma-mapping: remove dma_mark_declared_memory_occupied
  dma-mapping: move CONFIG_DMA_CMA to kernel/dma/Kconfig
  dma-mapping: improve selection of dma_declare_coherent availability
  dma-mapping: remove an incorrect __iommem annotation
  of: select OF_RESERVED_MEM automatically
  device.h: dma_mem is only needed for HAVE_GENERIC_DMA_COHERENT
  mfd/sm501: depend on HAS_DMA
  dma-mapping: add a kconfig symbol for arch_teardown_dma_ops availability
  dma-mapping: add a kconfig symbol for arch_setup_dma_ops availability
  dma-mapping: move debug configuration options to kernel/dma
  dma-debug: add dumping facility via debugfs
  dma: debug: no need to check return value of debugfs_create functions
  videobuf2: replace a layering violation with dma_map_resource
  dma-mapping: don't BUG when calling dma_map_resource on RAM
  ...

ARCv2: spinlock: remove the extra smp_mb before lock, after unlock

2019-03-08T19:17:49+00:00

 - ARCv2 LLSC spinlocks have smp_mb() both before and after the LLSC
   instructions, which is not required per lkmm ACQ/REL semantics.
   smp_mb() is only needed _after_ lock and _before_ unlock.
   So remove the extra barriers.
   The reason they were there was mainly historical. At the time of
   initial SMP Linux bringup on HS38 cores, I was too conservative,
   given the fluidity of both hw and sw. The last attempt to ditch the
   extra barrier showed some hackbench regression which is apparently
   not the case now (atleast for LLSC case, read on...)

 - EX based spinlocks (!CONFIG_ARC_HAS_LLSC) still needs the extra
   smp_mb(), not due to lkmm, but due to some hardware shenanigans.
   W/o that, hackbench triggers RCU stall splat so extra DMB is retained
   !LLSC based systems are not realistic Linux sstem anyways so they can
   afford to be a nit suboptimal ;-)

   | [ARCLinux]# for i in (seq 1 1 5) ; do hackbench; done
   | Running with 10 groups 400 process
   | INFO: task hackbench:158 blocked for more than 10 seconds.
   |       Not tainted 4.20.0-00005-g96b18288a88e-dirty #117
   | "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
   | hackbench       D    0   158    135 0x00000000
   |
   | Stack Trace:
   | watchdog: BUG: soft lockup - CPU#3 stuck for 59s! [hackbench:469]
   | Modules linked in:
   | Path: (null)
   | CPU: 3 PID: 469 Comm: hackbench Not tainted 4.20.0-00005-g96b18288a88e-dirty
   |
   | [ECR   ]: 0x00000000 => Check Programmer's Manual
   | [EFA   ]: 0x00000000
   | [BLINK ]: do_exit+0x4a6/0x7d0
   | [ERET  ]: _raw_write_unlock_irq+0x44/0x5c

 - And while at it, remove the extar smp_mb() from EX based
   arch_read_trylock() since the spin lock there guarantees a full
   barrier anyways

 - For LLSC case, hackbench threads improves with this patch (HAPS @ 50MHz)

   ---- before ----
   |
   | [ARCLinux]# for i in 1 2 3 4 5; do hackbench 10 thread; done
   | Running with 10 groups 400 threads
   | Time: 16.253
   | Time: 16.445
   | Time: 16.590
   | Time: 16.721
   | Time: 16.544

   ---- after ----
   |
   | [ARCLinux]# for i in 1 2 3 4 5; do hackbench 10 thread; done
   | Running with 10 groups 400 threads
   | Time: 15.638
   | Time: 15.730
   | Time: 15.870
   | Time: 15.842
   | Time: 15.729

Acked-by: Peter Zijlstra (Intel) 
Signed-off-by: Vineet Gupta

ARC: boot log: cut down on verbosity

2019-02-25T23:12:23+00:00

The syscall ABI has long been fixed, so no need to call that out now.

Also, there's no need to print really fine details such as norm,
barrel-shifter etc. Those are given in a Linux enabled hardware config.
So now we print just 1 line for all optional "instruction" related
hardware features

|
| ISA Extn	: atomic ll64 unalign mpy[opt 9] div_rem

vs. 2 before

|
|ISA Extn	: atomic ll64 unalign
|		: mpy[opt 9] div_rem norm barrel-shift swap minmax swape

Signed-off-by: Vineet Gupta

ARCv2: boot log: refurbish HS core/release identification

2019-02-25T23:09:44+00:00

HS core names and releases have so far been identified based solely on
IDENTIFY.ARCVER field. With the future HS releases this will not
be sufficient as same ARCVER 0x54 could be an HS38 or HS48.

So rewrite the code to use a new BCR to identify the cores properly.

Signed-off-by: Vineet Gupta

ARC: perf: bpok condition only exists for ARCompact

2019-02-25T20:11:00+00:00

Signed-off-by: Vineet Gupta

ARCv2: Add explcit unaligned access support (and ability to disable too)

2019-02-25T20:10:58+00:00

As of today we enable unaligned access unconditionally on ARCv2.
Do this under a Kconfig option to allow disable it for test, benchmarking
etc. Also while at it

  - Select HAVE_EFFICIENT_UNALIGNED_ACCESS
  - Although gcc defaults to unaligned access (since GNU 2018.03), add the
    right toggles for enabling or disabling as appropriate
  - update bootlog to prints both HW feature status (exists, enabled/disabled)
    and SW status (used / not used).
  - wire up the relaxed memcpy for unaligned access

Signed-off-by: Eugeniy Paltsev 
Signed-off-by: Vineet Gupta 
[vgupta: squashed patches, handle gcc -mno-unaligned-access quick]

ARCv2: don't assume core 0x54 has dual issue

2019-02-21T22:53:36+00:00

The first release of core4 (0x54) was dual issue only (HS4x).
Newer releases allow hardware to be configured as single issue (HS3x)
or dual issue.

Prevent accessing a HS4x only aux register in HS3x, which otherwise
leads to illegal instruction exceptions

Signed-off-by: Vineet Gupta