We'd like to get to the stage where the OPAL API is defined in a header
that is identical between Linux and Skiboot.

As step one, split the bits that actually define the API into
opal-api.h. The Linux specific parts stay in opal.h.
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Acked-by: NStewart Smith <stewart@linux.vnet.ibm.com>

The $(image-n) variable will never exist, because unset Kconfig options
are '' and not 'n'.
Signed-off-by: NMichal Marek <mmarek@suse.cz>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

The kfree() function tests whether its argument is NULL and then returns
immediately. Thus the test around the call is not needed.

This issue was detected by using the Coccinelle software.
Signed-off-by: NMarkus Elfring <elfring@users.sourceforge.net>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Not all OPAL platforms support resending system dumps, so check
that current firmware supports it first. Otherwise we get firmware
complaining:
"OPAL: Called with bad token 91 !"
Signed-off-by: NStewart Smith <stewart@linux.vnet.ibm.com>
Acked-by: NVasant Hegde <hegdevasant@linux.vnet.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Otherwise firmware complains: "OPAL: Called with bad token 74 !"
as not all OPAL systems have the ability to resend error logs.
Signed-off-by: NStewart Smith <stewart@linux.vnet.ibm.com>
Acked-by: NVasant Hegde <hegdevasant@linux.vnet.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Correct use of REGISTER/UNREGISTER is to check if the token exists
before calling. If we don't we get a "OPAL: Called with bad token 101 !"
error, which is harmless but may be alarming to some.
Signed-off-by: NStewart Smith <stewart@linux.vnet.ibm.com>
Acked-by: NVasant Hegde <hegdevasant@linux.vnet.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

As our various loops (copy, string, crypto etc) get more complicated,
we want to share implementations between userspace (eg glibc) and
the kernel. We also want to write userspace test harnesses to put
in tools/testing/selftest.

One gratuitous difference between userspace and the kernel is the
VSX register definitions - the kernel uses vsrX whereas gcc uses
vsX.

Change the kernel to match userspace.
Signed-off-by: NAnton Blanchard <anton@samba.org>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

As our various loops (copy, string, crypto etc) get more complicated,
we want to share implementations between userspace (eg glibc) and
the kernel. We also want to write userspace test harnesses to put
in tools/testing/selftest.

One gratuitous difference between userspace and the kernel is the
VMX register definitions - the kernel uses vrX whereas both gcc and
glibc use vX.

Change the kernel to match userspace.
Signed-off-by: NAnton Blanchard <anton@samba.org>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

After d905c5df ("PPC: POWERNV: move iommu_add_device earlier"), the
refcnt on the kobject backing the IOMMU group for a PCI device is
elevated by each call to pci_dma_dev_setup_pSeriesLP() (via
set_iommu_table_base_and_group). When we go to dlpar a multi-function
PCI device out:

        iommu_reconfig_notifier ->
                iommu_free_table ->
                        iommu_group_put
                        BUG_ON(tbl->it_group)

We trip this BUG_ON, because there are still references on the table, so
it is not freed. Fix this by moving the powernv bus notifier to common
code and calling it for both powernv and pseries.

Fixes: d905c5df ("PPC: POWERNV: move iommu_add_device earlier")
Signed-off-by: NNishanth Aravamudan <nacc@linux.vnet.ibm.com>
Tested-by: NNishanth Aravamudan <nacc@linux.vnet.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Anton has a busy ppc64le KVM box where guests sometimes hit the infamous
"kernel BUG at kernel/smpboot.c:134!" issue during boot:

  BUG_ON(td->cpu != smp_processor_id());

Basically a per CPU hotplug thread scheduled on the wrong CPU. The oops
output confirms it:

  CPU: 0
  Comm: watchdog/130

The problem is that we aren't ensuring the CPU active bit is set for the
secondary before allowing the master to continue on. The master unparks
the secondary CPU's kthreads and the scheduler looks for a CPU to run
on. It calls select_task_rq() and realises the suggested CPU is not in
the cpus_allowed mask. It then ends up in select_fallback_rq(), and
since the active bit isnt't set we choose some other CPU to run on.

This seems to have been introduced by 6acbfb96 "sched: Fix hotplug
vs. set_cpus_allowed_ptr()", which changed from setting active before
online to setting active after online. However that was in turn fixing a
bug where other code assumed an active CPU was also online, so we can't
just revert that fix.

The simplest fix is just to spin waiting for both active & online to be
set. We already have a barrier prior to set_cpu_online() (which also
sets active), to ensure all other setup is completed before online &
active are set.

Fixes: 6acbfb96 ("sched: Fix hotplug vs. set_cpus_allowed_ptr()")
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Signed-off-by: NAnton Blanchard <anton@samba.org>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Implement arch_irq_work_has_interrupt() for powerpc

Commit 9b01f5bf introduced a dependency on "IRQ work self-IPIs" for
full dynamic ticks to be enabled, by expecting architectures to
implement a suitable arch_irq_work_has_interrupt() routine.

Several arches have implemented this routine, including x86 (3010279f)
and arm (09f6edd4), but powerpc was omitted.

This patch implements this routine for powerpc.

The symptom, at boot (on powerpc systems) with "nohz_full=<CPU list>"
is displayed:

     NO_HZ: Can't run full dynticks because arch doesn't support irq work self-IPIs

after this patch:

     NO_HZ: Full dynticks CPUs: <CPU list>.

Tested against 3.19.

powerpc implements "IRQ work self-IPIs" by setting the decrementer to 1 in
arch_irq_work_raise(), which causes a decrementer exception on the next
timebase tick. We then handle the work in __timer_interrupt().

CC: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: NPaul A. Clarke <pc@us.ibm.com>
Reviewed-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
[mpe: Flesh out change log, fix ws & include guards, remove include of processor.h]
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Change-Id: I1a80ad7b9f6854791bd270b746f93a91439155a6
Signed-off-by: NEmil Medve <Emilian.Medve@Freescale.com>
Acked-by: NTang Yuantian <Yuantian.Tang@freescale.com>
Signed-off-by: NMichael Turquette <mturquette@linaro.org>

Add a new kexec preprocessor macro IND_FLAGS, which is the bitwise OR of
all the possible kexec IND_ kimage_entry indirection flags.  Having this
macro allows for simplified code in the prosessing of the kexec
kimage_entry items.  Also, remove the local powerpc definition and use the
generic one.
Signed-off-by: NGeoff Levand <geoff@infradead.org>
Acked-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: NVivek Goyal <vgoyal@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Maximilian Attems <max@stro.at>
Cc: Michal Marek <mmarek@suse.cz>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

We've replaced remap_file_pages(2) implementation with emulation.  Nobody
creates non-linear mapping anymore.
Signed-off-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

printk and friends can now format bitmaps using '%*pb[l]'.  cpumask
and nodemask also provide cpumask_pr_args() and nodemask_pr_args()
respectively which can be used to generate the two printf arguments
necessary to format the specified cpu/nodemask.

* Spurious if (len > 1) test dropped from shared_cpu_map_show().
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

On POWER8 virtualised kernels the VTB register can be read to have a view
of time that only increases while the guest is running.  This will prevent
guests from seeing time jump if a guest is paused for significant amounts
of time.

On POWER7 and below virtualised kernels stolen time is subtracted from
local_clock as a best effort approximation.  This will not eliminate
spurious warnings in the case of a suspended guest but may reduce the
occurance in the case of softlockups due to host over commit.

Bare metal kernels should avoid reading the VTB as KVM does not restore
sane values when not executing, the approxmation is fine as host kernels
won't observe any stolen time.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: NCyril Bur <cyrilbur@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Andrew Jones <drjones@redhat.com>
Acked-by: NDon Zickus <dzickus@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Ulrich Obergfell <uobergfe@redhat.com>
Cc: chai wen <chaiw.fnst@cn.fujitsu.com>
Cc: Fabian Frederick <fabf@skynet.be>
Cc: Aaron Tomlin <atomlin@redhat.com>
Cc: Ben Zhang <benzh@chromium.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

If an attacker can cause a controlled kernel stack overflow, overwriting
the restart block is a very juicy exploit target.  This is because the
restart_block is held in the same memory allocation as the kernel stack.

Moving the restart block to struct task_struct prevents this exploit by
making the restart_block harder to locate.

Note that there are other fields in thread_info that are also easy
targets, at least on some architectures.

It's also a decent simplification, since the restart code is more or less
identical on all architectures.

[james.hogan@imgtec.com: metag: align thread_info::supervisor_stack]
Signed-off-by: NAndy Lutomirski <luto@amacapital.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: David Miller <davem@davemloft.net>
Acked-by: NRichard Weinberger <richard@nod.at>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Haavard Skinnemoen <hskinnemoen@gmail.com>
Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no>
Cc: Steven Miao <realmz6@gmail.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Aurelien Jacquiot <a-jacquiot@ti.com>
Cc: Mikael Starvik <starvik@axis.com>
Cc: Jesper Nilsson <jesper.nilsson@axis.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Richard Kuo <rkuo@codeaurora.org>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Helge Deller <deller@gmx.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Tested-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Chen Liqin <liqin.linux@gmail.com>
Cc: Lennox Wu <lennox.wu@gmail.com>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Cc: Chris Zankel <chris@zankel.net>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: NJames Hogan <james.hogan@imgtec.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch removes the NUMA PTE bits and associated helpers.  As a
side-effect it increases the maximum possible swap space on x86-64.

One potential source of problems is races between the marking of PTEs
PROT_NONE, NUMA hinting faults and migration.  It must be guaranteed that
a PTE being protected is not faulted in parallel, seen as a pte_none and
corrupting memory.  The base case is safe but transhuge has problems in
the past due to an different migration mechanism and a dependance on page
lock to serialise migrations and warrants a closer look.

task_work hinting update			parallel fault
------------------------			--------------
change_pmd_range
  change_huge_pmd
    __pmd_trans_huge_lock
      pmdp_get_and_clear
						__handle_mm_fault
						pmd_none
						  do_huge_pmd_anonymous_page
						  read? pmd_lock blocks until hinting complete, fail !pmd_none test
						  write? __do_huge_pmd_anonymous_page acquires pmd_lock, checks pmd_none
      pmd_modify
      set_pmd_at

task_work hinting update			parallel migration
------------------------			------------------
change_pmd_range
  change_huge_pmd
    __pmd_trans_huge_lock
      pmdp_get_and_clear
						__handle_mm_fault
						  do_huge_pmd_numa_page
						    migrate_misplaced_transhuge_page
						    pmd_lock waits for updates to complete, recheck pmd_same
      pmd_modify
      set_pmd_at

Both of those are safe and the case where a transhuge page is inserted
during a protection update is unchanged.  The case where two processes try
migrating at the same time is unchanged by this series so should still be
ok.  I could not find a case where we are accidentally depending on the
PTE not being cleared and flushed.  If one is missed, it'll manifest as
corruption problems that start triggering shortly after this series is
merged and only happen when NUMA balancing is enabled.
Signed-off-by: NMel Gorman <mgorman@suse.de>
Tested-by: NSasha Levin <sasha.levin@oracle.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Dave Jones <davej@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

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

Convert existing users of pte_numa and friends to the new helper.  Note
that the kernel is broken after this patch is applied until the other page
table modifiers are also altered.  This patch layout is to make review
easier.
Signed-off-by: NMel Gorman <mgorman@suse.de>
Acked-by: NLinus Torvalds <torvalds@linux-foundation.org>
Acked-by: NAneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Tested-by: NSasha Levin <sasha.levin@oracle.com>
Cc: Dave Jones <davej@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This is a preparatory patch that introduces protnone helpers for automatic
NUMA balancing.
Signed-off-by: NMel Gorman <mgorman@suse.de>
Acked-by: NLinus Torvalds <torvalds@linux-foundation.org>
Acked-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Tested-by: NSasha Levin <sasha.levin@oracle.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Dave Jones <davej@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

We don't have to use mm_walk->private to pass vma to the callback function
because of mm_walk->vma.  And walk_page_vma() is useful if we walk over a
single vma.
Signed-off-by: NNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

LKP has triggered a compiler warning after my recent patch "mm: account
pmd page tables to the process":

    mm/mmap.c: In function 'exit_mmap':
 >> mm/mmap.c:2857:2: warning: right shift count >= width of type [enabled by default]

The code:

 > 2857                WARN_ON(mm_nr_pmds(mm) >
   2858                                round_up(FIRST_USER_ADDRESS, PUD_SIZE) >> PUD_SHIFT);

In this, on tile, we have FIRST_USER_ADDRESS defined as 0.  round_up() has
the same type -- int.  PUD_SHIFT.

I think the best way to fix it is to define FIRST_USER_ADDRESS as unsigned
long.  On every arch for consistency.
Signed-off-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reported-by: NWu Fengguang <fengguang.wu@intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Currently we have many duplicates in definitions around
follow_huge_addr(), follow_huge_pmd(), and follow_huge_pud(), so this
patch tries to remove the m.  The basic idea is to put the default
implementation for these functions in mm/hugetlb.c as weak symbols
(regardless of CONFIG_ARCH_WANT_GENERAL_HUGETL B), and to implement
arch-specific code only when the arch needs it.

For follow_huge_addr(), only powerpc and ia64 have their own
implementation, and in all other architectures this function just returns
ERR_PTR(-EINVAL).  So this patch sets returning ERR_PTR(-EINVAL) as
default.

As for follow_huge_(pmd|pud)(), if (pmd|pud)_huge() is implemented to
always return 0 in your architecture (like in ia64 or sparc,) it's never
called (the callsite is optimized away) no matter how implemented it is.
So in such architectures, we don't need arch-specific implementation.

In some architecture (like mips, s390 and tile,) their current
arch-specific follow_huge_(pmd|pud)() are effectively identical with the
common code, so this patch lets these architecture use the common code.

One exception is metag, where pmd_huge() could return non-zero but it
expects follow_huge_pmd() to always return NULL.  This means that we need
arch-specific implementation which returns NULL.  This behavior looks
strange to me (because non-zero pmd_huge() implies that the architecture
supports PMD-based hugepage, so follow_huge_pmd() can/should return some
relevant value,) but that's beyond this cleanup patch, so let's keep it.

Justification of non-trivial changes:
- in s390, follow_huge_pmd() checks !MACHINE_HAS_HPAGE at first, and this
  patch removes the check. This is OK because we can assume MACHINE_HAS_HPAGE
  is true when follow_huge_pmd() can be called (note that pmd_huge() has
  the same check and always returns 0 for !MACHINE_HAS_HPAGE.)
- in s390 and mips, we use HPAGE_MASK instead of PMD_MASK as done in common
  code. This patch forces these archs use PMD_MASK, but it's OK because
  they are identical in both archs.
  In s390, both of HPAGE_SHIFT and PMD_SHIFT are 20.
  In mips, HPAGE_SHIFT is defined as (PAGE_SHIFT + PAGE_SHIFT - 3) and
  PMD_SHIFT is define as (PAGE_SHIFT + PAGE_SHIFT + PTE_ORDER - 3), but
  PTE_ORDER is always 0, so these are identical.
Signed-off-by: NNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: NHugh Dickins <hughd@google.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Cc: Nishanth Aravamudan <nacc@linux.vnet.ibm.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Steve Capper <steve.capper@linaro.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch introduces a new module parameter for the KVM module; when it
is present, KVM attempts a bit of polling on every HLT before scheduling
itself out via kvm_vcpu_block.

This parameter helps a lot for latency-bound workloads---in particular
I tested it with O_DSYNC writes with a battery-backed disk in the host.
In this case, writes are fast (because the data doesn't have to go all
the way to the platters) but they cannot be merged by either the host or
the guest.  KVM's performance here is usually around 30% of bare metal,
or 50% if you use cache=directsync or cache=writethrough (these
parameters avoid that the guest sends pointless flush requests, and
at the same time they are not slow because of the battery-backed cache).
The bad performance happens because on every halt the host CPU decides
to halt itself too.  When the interrupt comes, the vCPU thread is then
migrated to a new physical CPU, and in general the latency is horrible
because the vCPU thread has to be scheduled back in.

With this patch performance reaches 60-65% of bare metal and, more
important, 99% of what you get if you use idle=poll in the guest.  This
means that the tunable gets rid of this particular bottleneck, and more
work can be done to improve performance in the kernel or QEMU.

Of course there is some price to pay; every time an otherwise idle vCPUs
is interrupted by an interrupt, it will poll unnecessarily and thus
impose a little load on the host.  The above results were obtained with
a mostly random value of the parameter (500000), and the load was around
1.5-2.5% CPU usage on one of the host's core for each idle guest vCPU.

The patch also adds a new stat, /sys/kernel/debug/kvm/halt_successful_poll,
that can be used to tune the parameter.  It counts how many HLT
instructions received an interrupt during the polling period; each
successful poll avoids that Linux schedules the VCPU thread out and back
in, and may also avoid a likely trip to C1 and back for the physical CPU.

While the VM is idle, a Linux 4 VCPU VM halts around 10 times per second.
Of these halts, almost all are failed polls.  During the benchmark,
instead, basically all halts end within the polling period, except a more
or less constant stream of 50 per second coming from vCPUs that are not
running the benchmark.  The wasted time is thus very low.  Things may
be slightly different for Windows VMs, which have a ~10 ms timer tick.

The effect is also visible on Marcelo's recently-introduced latency
test for the TSC deadline timer.  Though of course a non-RT kernel has
awful latency bounds, the latency of the timer is around 8000-10000 clock
cycles compared to 20000-120000 without setting halt_poll_ns.  For the TSC
deadline timer, thus, the effect is both a smaller average latency and
a smaller variance.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Kim Phillips reported following build failure.

  LD      init/built-in.o
  mm/built-in.o: In function `free_pages_prepare':
  mm/page_alloc.c:770: undefined reference to `.kernel_map_pages'
  mm/built-in.o: In function `prep_new_page':
  mm/page_alloc.c:933: undefined reference to `.kernel_map_pages'
  mm/built-in.o: In function `map_pages':
  mm/compaction.c:61: undefined reference to `.kernel_map_pages'
  make: *** [vmlinux] Error 1

Reason for this problem is that commit 031bc574
("mm/debug-pagealloc: make debug-pagealloc boottime configurable")
forgot to remove the old declaration of kernel_map_pages() for some
architectures.  This patch removes them to fix build failure.
Reported-by: NKim Phillips <kim.phillips@freescale.com>
Signed-off-by: NJoonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: David Miller <davem@davemloft.net>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Function __flush_tlb_page() must only be called for user contexts, so
put in extra hardening to warn on calling it for kernel context.
Signed-off-by: NArseny Solokha <asolokha@kb.kras.ru>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Register a notifier for a OPAL message indicating that the machine
should prepare itself for a graceful power off.

OPAL will tell us if the power off is a reboot or shutdown, but for now
we perform the same orderly_poweroff action.
Signed-off-by: NJoel Stanley <joel@jms.id.au>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Currently a PAMU driver patch is very likely to receive some
checkpatch complaints about the code in the context of the
patch. This patch is an attempt to fix most of that and make
the driver more readable

Also fixed a subset of the sparse and coccinelle reported
issues.
Signed-off-by: NEmil Medve <Emilian.Medve@Freescale.com>
Signed-off-by: NJoerg Roedel <jroedel@suse.de>

Add the remaining gpci requests that contain counters suitable for use
by perf. Omit those that don't contain any counters (but note their
ommision).
Signed-off-by: NCody P Schafer <cody@linux.vnet.ibm.com>
Signed-off-by: NSukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

This adds (in req-gen/) a framework for defining gpci counter requests.
It uses macro magic similar to ftrace.

Also convert the existing hv-gpci request structures and enum values to
use the new framework (and adjust old users of the structs and enum
values to cope with changes in naming).

In exchange for this macro disaster, we get autogenerated event listing
for GPCI in sysfs, build time field offset checking, and zero
duplication of information about GPCI requests.
Signed-off-by: NCody P Schafer <cody@linux.vnet.ibm.com>
Signed-off-by: NSukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Retrieves and parses the 24x7 catalog on POWER systems that supply it
(right now, only POWER 8). Events are exposed via sysfs in the standard
fashion, and are all parameterized.

	$ cd /sys/bus/event_source/devices/hv_24x7/events

	$ cat HPM_CS_FROM_L4_LDATA__PHYS_CORE
	domain=0x2,offset=0xd58,core=?,lpar=0x0

	$ cat HPM_TLBIE__VCPU_HOME_CHIP
	domain=0x4,offset=0x358,vcpu=?,lpar=?

where user is required to specify values for the fields with '?' (like
core, vcpu, lpar above), when specifying the event with the perf tool.

Catalog is (at the moment) only parsed on boot. It needs re-parsing
when a some hypervisor events occur. At that point we'll also need to
prevent old events from continuing to function (counter that is passed
in via spare space in the config values?).
Signed-off-by: NCody P Schafer <cody@linux.vnet.ibm.com>
Signed-off-by: NSukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Define a lite version of the EVENT_DEFINE_RANGE_FORMAT() that avoids
defining helper functions for the bit-field ranges.
Signed-off-by: NSukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

As commit 50ba08f3 ("of/fdt: Don't clear initial_boot_params
if fdt_check_header() fails") does, the device-tree pointer
"initial_boot_params" is initialized by early_init_dt_verify(),
which is called by early_init_devtree(). So we needn't explicitly
initialize that again in early_init_devtree().
Signed-off-by: NGavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

We have code to do syscall tracing which is disabled at compile time by
default. It's not been touched since the dawn of time (ie. v2.6.12).

There are now better ways to do syscall tracing, ie. using the
raw_syscall, or syscall tracepoints.

For the specific case of tracing syscalls at boot on a system that
doesn't get to userspace, you can boot with:

  trace_event=syscalls tp_printk=on

Which will trace syscalls from boot, and echo all output to the console.
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Currently when we back trace something that is in a syscall we see
something like this:

[c000000000000000] [c000000000000000] SyS_read+0x6c/0x110
[c000000000000000] [c000000000000000] syscall_exit+0x0/0x98

Although it's entirely correct, seeing syscall_exit at the bottom can be
confusing - we were exiting from a syscall and then called SyS_read() ?

If we instead change syscall_exit to be a local label we get something
more intuitive:

[c0000001fa46fde0] [c00000000026719c] SyS_read+0x6c/0x110
[c0000001fa46fe30] [c000000000009264] system_call+0x38/0xd0

ie. we were handling a system call, and it was SyS_read().
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

When unbinding and rebinding the driver on a system with a card in PHB0, this
error condition is reached after a few attempts:

ERROR: Bad of_node_put() on /pciex@3fffe40000000
CPU: 0 PID: 3040 Comm: bash Not tainted 3.18.0-rc3-12545-g3627ffe #152
Call Trace:
[c000000721acb5c0] [c00000000086ef94] .dump_stack+0x84/0xb0 (unreliable)
[c000000721acb640] [c00000000073a0a8] .of_node_release+0xd8/0xe0
[c000000721acb6d0] [c00000000044bc44] .kobject_release+0x74/0xe0
[c000000721acb760] [c0000000007394fc] .of_node_put+0x1c/0x30
[c000000721acb7d0] [c000000000545cd8] .cxl_probe+0x1a98/0x1d50
[c000000721acb900] [c0000000004845a0] .local_pci_probe+0x40/0xc0
[c000000721acb980] [c000000000484998] .pci_device_probe+0x128/0x170
[c000000721acba30] [c00000000052400c] .driver_probe_device+0xac/0x2a0
[c000000721acbad0] [c000000000522468] .bind_store+0x108/0x160
[c000000721acbb70] [c000000000521448] .drv_attr_store+0x38/0x60
[c000000721acbbe0] [c000000000293840] .sysfs_kf_write+0x60/0xa0
[c000000721acbc50] [c000000000292500] .kernfs_fop_write+0x140/0x1d0
[c000000721acbcf0] [c000000000208648] .vfs_write+0xd8/0x260
[c000000721acbd90] [c000000000208b18] .SyS_write+0x58/0x100
[c000000721acbe30] [c000000000009258] syscall_exit+0x0/0x98

We are missing a call to of_node_get(). pnv_pci_to_phb_node() should
call of_node_get() otherwise np's reference count isn't incremented and
it might go away. Rename pnv_pci_to_phb_node() to pnv_pci_get_phb_node()
so it's clear it calls of_node_get().
Signed-off-by: NRyan Grimm <grimm@linux.vnet.ibm.com>
Acked-by: NIan Munsie <imunsie@au1.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

MMU_NO_CONTEXT is conditionally defined as 0 or (unsigned int)-1. However,
in __flush_tlb_page() a corresponding variable is only tested for open
coded 0, which can cause NULL pointer dereference if `mm' argument was
legitimately passed as such.

Bail out early in case the first argument is NULL, thus eliminate confusion
between different values of MMU_NO_CONTEXT and avoid disabling and then
re-enabling preemption unnecessarily.
Signed-off-by: NArseny Solokha <asolokha@kb.kras.ru>
Signed-off-by: NScott Wood <scottwood@freescale.com>

Convert the powermac PCI driver to use the generic config access functions.

This changes accesses from (in|out)_(8|le16|le32) to readX/writeX variants.
I believe these should be equivalent for PCI config space accesses, but
confirmation would be nice.
Signed-off-by: NRob Herring <robh@kernel.org>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: Paul Mackerras <paulus@samba.org>
CC: Michael Ellerman <mpe@ellerman.id.au>
CC: linuxppc-dev@lists.ozlabs.org

Convert the fsl_pci driver to use the generic config access functions.

This changes accesses from (in|out)_(8|le16|le32) to readX/writeX variants.
I believe these should be equivalent for PCI config space accesses, but
confirmation would be nice.
Signed-off-by: NRob Herring <robh@kernel.org>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: Paul Mackerras <paulus@samba.org>
CC: Michael Ellerman <mpe@ellerman.id.au>
CC: linuxppc-dev@lists.ozlabs.org