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  1. 05 1月, 2017 5 次提交
    • J
      KVM: VMX: remove duplicated declaration · 69130ea1
      由 Jan Dakinevich 提交于 
      Declaration of VMX_VPID_EXTENT_SUPPORTED_MASK occures twice in the code.
Probably, it was happened after unsuccessful merge.
Signed-off-by: NJan Dakinevich <jan.dakinevich@gmail.com>
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>
      69130ea1
    • J
      KVM: MIPS: Flush KVM entry code from icache globally · 32eb12a6
      由 James Hogan 提交于 
      Flush the KVM entry code from the icache on all CPUs, not just the one
that built the entry code.
Signed-off-by: NJames Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Cc: <stable@vger.kernel.org> # 3.16.x-
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>
      32eb12a6
    • J
      KVM: MIPS: Don't clobber CP0_Status.UX · 4c881451
      由 James Hogan 提交于 
      On 64-bit kernels, MIPS KVM will clear CP0_Status.UX to prevent the
guest (running in user mode) from accessing the 64-bit memory segments.
However the previous value of CP0_Status.UX is never restored when
exiting from the guest.

If the user process uses 64-bit addressing (the n64 ABI) this can result
in address error exceptions from the kernel if it needs to deliver a
signal before returning to user mode, as the kernel will need to write a
sigframe to high user addresses on the user stack which are disallowed
by CP0_Status.UX=0.

This is fixed by explicitly setting SX and UX again when exiting from
the guest, and explicitly clearing those bits when returning to the
guest. Having the SX and UX bits set when handling guest exits (rather
than only when exiting to userland) will be helpful when we support VZ,
since we shouldn't need to directly read or write guest memory, so it
will be valid for cache management IPIs to access host user addresses.
Signed-off-by: NJames Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Cc: <stable@vger.kernel.org> # 4.8.x-
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>
      4c881451
    • M
      arm64: restore get_current() optimisation · 9d84fb27
      由 Mark Rutland 提交于 
      Commit c02433dd ("arm64: split thread_info from task stack")
inverted the relationship between get_current() and
current_thread_info(), with sp_el0 now holding the current task_struct
rather than the current thead_info. The new implementation of
get_current() prevents the compiler from being able to optimize repeated
calls to either, resulting in a noticeable penalty in some
microbenchmarks.

This patch restores the previous optimisation by implementing
get_current() in the same way as our old current_thread_info(), using a
non-volatile asm statement.
Acked-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NMark Rutland <mark.rutland@arm.com>
Reported-by: NDavidlohr Bueso <dbueso@suse.de>
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>
      9d84fb27
    • M
      arm64: mm: fix show_pte KERN_CONT fallout · 6ef4fb38
      由 Mark Rutland 提交于 
      Recent changes made KERN_CONT mandatory for continued lines. In the
absence of KERN_CONT, a newline may be implicit inserted by the core
printk code.

In show_pte, we (erroneously) use printk without KERN_CONT for continued
prints, resulting in output being split across a number of lines, and
not matching the intended output, e.g.

[ff000000000000] *pgd=00000009f511b003
, *pud=00000009f4a80003
, *pmd=0000000000000000

Fix this by using pr_cont() for all the continuations.
Acked-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NMark Rutland <mark.rutland@arm.com>
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>
      6ef4fb38
  3. 04 1月, 2017 3 次提交
  5. 03 1月, 2017 3 次提交
  7. 02 1月, 2017 9 次提交
  9. 31 12月, 2016 1 次提交
  11. 30 12月, 2016 5 次提交
    • S
      arm64: dts: vexpress: Support GICC_DIR operations · 1dff32d7
      由 Sudeep Holla 提交于 
      The GICv2 CPU interface registers span across 8K, not 4K as indicated in
the DT.  Only the GICC_DIR register is located after the initial 4K
boundary, leaving a functional system but without support for separately
EOI'ing and deactivating interrupts.

After this change the system supports split priority drop and interrupt
deactivation. This patch is based on similar one from Christoffer Dall:
commit 368400e2 ("ARM: dts: vexpress: Support GICC_DIR operations")
Signed-off-by: NSudeep Holla <sudeep.holla@arm.com>
      1dff32d7
    • C
      ARM: dts: vexpress: Support GICC_DIR operations · 368400e2
      由 Christoffer Dall 提交于 
      The GICv2 CPU interface registers span across 8K, not 4K as indicated in
the DT.  Only the GICC_DIR register is located after the initial 4K
boundary, leaving a functional system but without support for separately
EOI'ing and deactivating interrupts.

After this change the system supports split priority drop and interrupt
deactivation.
Acked-by: NMarc Zyngier <marc.zyngier@arm.com>
Signed-off-by: NChristoffer Dall <christoffer.dall@linaro.org>
[sudeep.holla@arm.com: included same fix for tc1 platform too]
Signed-off-by: NSudeep Holla <sudeep.holla@arm.com>
      368400e2
    • H
      parisc: Drop TIF_RESTORE_SIGMASK and switch to generic code · 1fe0a7e0
      由 Helge Deller 提交于 
      Commit 7e781418 ("signal: consolidate {TS,TLF}_RESTORE_SIGMASK code")
introduced code with which the "restore sigmask" flag lives in task_struct
instead of ti->flags. Let's use this optimization on parisc too.
Signed-off-by: NHelge Deller <deller@gmx.de>
      1fe0a7e0
    • H
      parisc: Mark cr16 clocksource unstable on SMP systems · 41744213
      由 Helge Deller 提交于 
      The cr16 interval timer of each CPU is not syncronized to other cr16
timers in other CPUs in a SMP system. So, delay the registration of the
cr16 clocksource until all CPUs have been detected and then - if we are
on a SMP machine - mark the cr16 clocksource as unstable and lower it's
rating before registering it at the clocksource framework.

This patch fixes the stalled CPU warnings which we have seen since
introduction of the cr16 clocksource.
Signed-off-by: NHelge Deller <deller@gmx.de>
Cc: <stable@vger.kernel.org> # v4.8+
      41744213
    • L
      mm: optimize PageWaiters bit use for unlock_page() · b91e1302
      由 Linus Torvalds 提交于 
      In commit 62906027 ("mm: add PageWaiters indicating tasks are
waiting for a page bit") Nick Piggin made our page locking no longer
unconditionally touch the hashed page waitqueue, which not only helps
performance in general, but is particularly helpful on NUMA machines
where the hashed wait queues can bounce around a lot.

However, the "clear lock bit atomically and then test the waiters bit"
sequence turns out to be much more expensive than it needs to be,
because you get a nasty stall when trying to access the same word that
just got updated atomically.

On architectures where locking is done with LL/SC, this would be trivial
to fix with a new primitive that clears one bit and tests another
atomically, but that ends up not working on x86, where the only atomic
operations that return the result end up being cmpxchg and xadd.  The
atomic bit operations return the old value of the same bit we changed,
not the value of an unrelated bit.

On x86, we could put the lock bit in the high bit of the byte, and use
"xadd" with that bit (where the overflow ends up not touching other
bits), and look at the other bits of the result.  However, an even
simpler model is to just use a regular atomic "and" to clear the lock
bit, and then the sign bit in eflags will indicate the resulting state
of the unrelated bit #7.

So by moving the PageWaiters bit up to bit #7, we can atomically clear
the lock bit and test the waiters bit on x86 too.  And architectures
with LL/SC (which is all the usual RISC suspects), the particular bit
doesn't matter, so they are fine with this approach too.

This avoids the extra access to the same atomic word, and thus avoids
the costly stall at page unlock time.

The only downside is that the interface ends up being a bit odd and
specialized: clear a bit in a byte, and test the sign bit.  Nick doesn't
love the resulting name of the new primitive, but I'd rather make the
name be descriptive and very clear about the limitation imposed by
trying to work across all relevant architectures than make it be some
generic thing that doesn't make the odd semantics explicit.

So this introduces the new architecture primitive

    clear_bit_unlock_is_negative_byte();

and adds the trivial implementation for x86.  We have a generic
non-optimized fallback (that just does a "clear_bit()"+"test_bit(7)"
combination) which can be overridden by any architecture that can do
better.  According to Nick, Power has the same hickup x86 has, for
example, but some other architectures may not even care.

All these optimizations mean that my page locking stress-test (which is
just executing a lot of small short-lived shell scripts: "make test" in
the git source tree) no longer makes our page locking look horribly bad.
Before all these optimizations, just the unlock_page() costs were just
over 3% of all CPU overhead on "make test".  After this, it's down to
0.66%, so just a quarter of the cost it used to be.

(The difference on NUMA is bigger, but there this micro-optimization is
likely less noticeable, since the big issue on NUMA was not the accesses
to 'struct page', but the waitqueue accesses that were already removed
by Nick's earlier commit).
Acked-by: NNick Piggin <npiggin@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Bob Peterson <rpeterso@redhat.com>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Andrew Lutomirski <luto@kernel.org>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      b91e1302
  13. 29 12月, 2016 1 次提交
  15. 28 12月, 2016 13 次提交