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  1. 30 8月, 2013 1 次提交
  3. 06 8月, 2013 1 次提交
  5. 23 7月, 2013 1 次提交
  7. 17 7月, 2013 1 次提交
    • H
      x86, bitops: Change bitops to be native operand size · 9b710506
      由 H. Peter Anvin 提交于 
      Change the bitops operation to be naturally "long", i.e. 63 bits on
the 64-bit kernel.  Additional bugs are likely to crop up in the
future.

We already have bugs which machines with > 16 TiB of memory in a
single node, as can happen if memory is interleaved.  The x86 bitop
operations take a signed index, so using an unsigned type is not an
option.

Jim Kukunas measured the effect of this patch on kernel size: it adds
2779 bytes to the allyesconfig kernel.  Some of that probably could be
elided by replacing the inline functions with macros which select the
32-bit type if the index is a 32-bit value, something like:

In that case we could also use "Jr" constraints for the 64-bit
version.

However, this would more than double the amount of code for a
relatively small gain.

Note that we can't use ilog2() for _BITOPS_LONG_SHIFT, as that causes
a recursive header inclusion problem.

The change to constant_test_bit() should both generate better code and
give correct result for negative bit indicies.  As previously written
the compiler had to generate extra code to create the proper wrong
result for negative values.
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>
Cc: Jim Kukunas <james.t.kukunas@intel.com>
Link: http://lkml.kernel.org/n/tip-z61ofiwe90xeyb461o72h8ya@git.kernel.org
      9b710506
  9. 29 6月, 2013 1 次提交
    • W
      x86: Use asm-goto to implement mutex fast path on x86-64 · 00e55a79
      由 Wedson Almeida Filho 提交于 
      The new implementation allows the compiler to better optimize the code; the
original implementation is still used when the kernel is compiled with older
versions of gcc that don't support asm-goto.

Compiling with gcc 4.7.3, the original mutex_lock() is 60 bytes with the fast
path taking 16 instructions; the new mutex_lock() is 42 bytes, with the fast
path taking 12 instructions.

The original mutex_unlock() is 24 bytes with the fast path taking 7
instructions; the new mutex_unlock() is 25 bytes (because the compiler used
a 2-byte ret) with the fast path taking 4 instructions.

The two versions of the functions are included below for reference.

Old:
ffffffff817742a0 <mutex_lock>:
ffffffff817742a0:       55                      push   %rbp
ffffffff817742a1:       48 89 e5                mov    %rsp,%rbp
ffffffff817742a4:       48 83 ec 10             sub    $0x10,%rsp
ffffffff817742a8:       48 89 5d f0             mov    %rbx,-0x10(%rbp)
ffffffff817742ac:       48 89 fb                mov    %rdi,%rbx
ffffffff817742af:       4c 89 65 f8             mov    %r12,-0x8(%rbp)
ffffffff817742b3:       e8 28 15 00 00          callq  ffffffff817757e0 <_cond_resched>
ffffffff817742b8:       48 89 df                mov    %rbx,%rdi
ffffffff817742bb:       f0 ff 0f                lock decl (%rdi)
ffffffff817742be:       79 05                   jns    ffffffff817742c5 <mutex_lock+0x25>
ffffffff817742c0:       e8 cb 04 00 00          callq  ffffffff81774790 <__mutex_lock_slowpath>
ffffffff817742c5:       65 48 8b 04 25 c0 b7    mov    %gs:0xb7c0,%rax
ffffffff817742cc:       00 00
ffffffff817742ce:       4c 8b 65 f8             mov    -0x8(%rbp),%r12
ffffffff817742d2:       48 89 43 18             mov    %rax,0x18(%rbx)
ffffffff817742d6:       48 8b 5d f0             mov    -0x10(%rbp),%rbx
ffffffff817742da:       c9                      leaveq
ffffffff817742db:       c3                      retq

ffffffff81774250 <mutex_unlock>:
ffffffff81774250:       55                      push   %rbp
ffffffff81774251:       48 c7 47 18 00 00 00    movq   $0x0,0x18(%rdi)
ffffffff81774258:       00
ffffffff81774259:       48 89 e5                mov    %rsp,%rbp
ffffffff8177425c:       f0 ff 07                lock incl (%rdi)
ffffffff8177425f:       7f 05                   jg     ffffffff81774266 <mutex_unlock+0x16>
ffffffff81774261:       e8 ea 04 00 00          callq  ffffffff81774750 <__mutex_unlock_slowpath>
ffffffff81774266:       5d                      pop    %rbp
ffffffff81774267:       c3                      retq

New:
ffffffff81774920 <mutex_lock>:
ffffffff81774920:       55                      push   %rbp
ffffffff81774921:       48 89 e5                mov    %rsp,%rbp
ffffffff81774924:       53                      push   %rbx
ffffffff81774925:       48 89 fb                mov    %rdi,%rbx
ffffffff81774928:       e8 a3 0e 00 00          callq  ffffffff817757d0 <_cond_resched>
ffffffff8177492d:       f0 ff 0b                lock decl (%rbx)
ffffffff81774930:       79 08                   jns    ffffffff8177493a <mutex_lock+0x1a>
ffffffff81774932:       48 89 df                mov    %rbx,%rdi
ffffffff81774935:       e8 16 fe ff ff          callq  ffffffff81774750 <__mutex_lock_slowpath>
ffffffff8177493a:       65 48 8b 04 25 c0 b7    mov    %gs:0xb7c0,%rax
ffffffff81774941:       00 00
ffffffff81774943:       48 89 43 18             mov    %rax,0x18(%rbx)
ffffffff81774947:       5b                      pop    %rbx
ffffffff81774948:       5d                      pop    %rbp
ffffffff81774949:       c3                      retq

ffffffff81774730 <mutex_unlock>:
ffffffff81774730:       48 c7 47 18 00 00 00    movq   $0x0,0x18(%rdi)
ffffffff81774737:       00
ffffffff81774738:       f0 ff 07                lock incl (%rdi)
ffffffff8177473b:       7f 0a                   jg     ffffffff81774747 <mutex_unlock+0x17>
ffffffff8177473d:       55                      push   %rbp
ffffffff8177473e:       48 89 e5                mov    %rsp,%rbp
ffffffff81774741:       e8 aa ff ff ff          callq  ffffffff817746f0 <__mutex_unlock_slowpath>
ffffffff81774746:       5d                      pop    %rbp
ffffffff81774747:       f3 c3                   repz retq
Signed-off-by: NWedson Almeida Filho <wedsonaf@gmail.com>
Link: http://lkml.kernel.org/r/1372420245-60021-1-git-send-email-wedsonaf@gmail.comSigned-off-by: NH. Peter Anvin <hpa@linux.intel.com>
      00e55a79
  11. 26 6月, 2013 4 次提交
  13. 19 6月, 2013 1 次提交
  15. 31 5月, 2013 1 次提交
  17. 28 5月, 2013 1 次提交
  19. 21 5月, 2013 2 次提交
  21. 15 5月, 2013 1 次提交
    • J
      time: Revert ALWAYS_USE_PERSISTENT_CLOCK compile time optimizaitons · b4f711ee
      由 John Stultz 提交于 
      Kay Sievers noted that the ALWAYS_USE_PERSISTENT_CLOCK config,
which enables some minor compile time optimization to avoid
uncessary code in mostly the suspend/resume path could cause
problems for userland.

In particular, the dependency for RTC_HCTOSYS on
!ALWAYS_USE_PERSISTENT_CLOCK, which avoids setting the time
twice and simplifies suspend/resume, has the side effect
of causing the /sys/class/rtc/rtcN/hctosys flag to always be
zero, and this flag is commonly used by udev to setup the
/dev/rtc symlink to /dev/rtcN, which can cause pain for
older applications.

While the udev rules could use some work to be less fragile,
breaking userland should strongly be avoided. Additionally
the compile time optimizations are fairly minor, and the code
being optimized is likely to be reworked in the future, so
lets revert this change.
Reported-by: NKay Sievers <kay@vrfy.org>
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>
Cc: stable <stable@vger.kernel.org> #3.9
Cc: Feng Tang <feng.tang@intel.com>
Cc: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Link: http://lkml.kernel.org/r/1366828376-18124-1-git-send-email-john.stultz@linaro.orgSigned-off-by: NThomas Gleixner <tglx@linutronix.de>
      b4f711ee
  23. 10 5月, 2013 4 次提交
  25. 09 5月, 2013 5 次提交
    • P
      KVM: emulator: emulate SALC · 326f578f
      由 Paolo Bonzini 提交于 
      This is an almost-undocumented instruction available in 32-bit mode.
I say "almost" undocumented because AMD documents it in their opcode
maps just to say that it is unavailable in 64-bit mode (sections
"A.2.1 One-Byte Opcodes" and "B.3 Invalid and Reassigned Instructions
in 64-Bit Mode").

It is roughly equivalent to "sbb %al, %al" except it does not
set the flags.  Use fastop to emulate it, but do not use the opcode
directly because it would fail if the host is 64-bit!
Reported-by: NJun'ichi Nomura <j-nomura@ce.jp.nec.com>
Cc: stable@vger.kernel.org # 3.9
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NGleb Natapov <gleb@redhat.com>
      326f578f
    • P
      KVM: emulator: emulate XLAT · 7fa57952
      由 Paolo Bonzini 提交于 
      This is used by SGABIOS, KVM breaks with emulate_invalid_guest_state=1.
It is just a MOV in disguise, with a funny source address.
Reported-by: NJun'ichi Nomura <j-nomura@ce.jp.nec.com>
Cc: stable@vger.kernel.org # 3.9
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NGleb Natapov <gleb@redhat.com>
      7fa57952
    • P
      KVM: emulator: emulate AAM · a035d5c6
      由 Paolo Bonzini 提交于 
      This is used by SGABIOS, KVM breaks with emulate_invalid_guest_state=1.

AAM needs the source operand to be unsigned; do the same in AAD as well
for consistency, even though it does not affect the result.
Reported-by: NJun'ichi Nomura <j-nomura@ce.jp.nec.com>
Cc: stable@vger.kernel.org # 3.9
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NGleb Natapov <gleb@redhat.com>
      a035d5c6
    • K
      x86/microcode: Add local mutex to fix physical CPU hot-add deadlock · 074d72ff
      由 Konrad Rzeszutek Wilk 提交于 
      This can easily be triggered if a new CPU is added (via
ACPI hotplug mechanism) and from user-space you do:

   echo 1 > /sys/devices/system/cpu/cpu3/online

(or wait for UDEV to do it) on a newly appeared physical CPU.

The deadlock is that the "store_online" in drivers/base/cpu.c
takes the cpu_hotplug_driver_lock() lock, then calls "cpu_up".
"cpu_up" eventually ends up calling "save_mc_for_early"
which also takes the cpu_hotplug_driver_lock() lock.

And here is that lockdep thinks of it:

 smpboot: Stack at about ffff880075c39f44
 smpboot: CPU3: has booted.
 microcode: CPU3 sig=0x206a7, pf=0x2, revision=0x25

 =============================================
 [ INFO: possible recursive locking detected ]
 3.9.0upstream-10129-g167af0e #1 Not tainted
 ---------------------------------------------
 sh/2487 is trying to acquire lock:
  (x86_cpu_hotplug_driver_mutex){+.+.+.}, at: [<ffffffff81075512>] cpu_hotplug_driver_lock+0x12/0x20

 but task is already holding lock:
  (x86_cpu_hotplug_driver_mutex){+.+.+.}, at: [<ffffffff81075512>] cpu_hotplug_driver_lock+0x12/0x20

 other info that might help us debug this:
  Possible unsafe locking scenario:

        CPU0
        ----
   lock(x86_cpu_hotplug_driver_mutex);
   lock(x86_cpu_hotplug_driver_mutex);

  *** DEADLOCK ***

  May be due to missing lock nesting notation

 6 locks held by sh/2487:
  #0:  (sb_writers#5){.+.+.+}, at: [<ffffffff811ca48d>] vfs_write+0x17d/0x190
  #1:  (&buffer->mutex){+.+.+.}, at: [<ffffffff812464ef>] sysfs_write_file+0x3f/0x160
  #2:  (s_active#20){.+.+.+}, at: [<ffffffff81246578>] sysfs_write_file+0xc8/0x160
  #3:  (x86_cpu_hotplug_driver_mutex){+.+.+.}, at: [<ffffffff81075512>] cpu_hotplug_driver_lock+0x12/0x20
  #4:  (cpu_add_remove_lock){+.+.+.}, at: [<ffffffff810961c2>] cpu_maps_update_begin+0x12/0x20
  #5:  (cpu_hotplug.lock){+.+.+.}, at: [<ffffffff810962a7>] cpu_hotplug_begin+0x27/0x60
Suggested-and-Acked-by: NBorislav Petkov <bp@alien8.de>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: fenghua.yu@intel.com
Cc: xen-devel@lists.xensource.com
Cc: stable@vger.kernel.org # for v3.9
Link: http://lkml.kernel.org/r/1368029583-23337-1-git-send-email-konrad.wilk@oracle.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      074d72ff
    • G
      KVM: VMX: fix halt emulation while emulating invalid guest sate · 8d76c49e
      由 Gleb Natapov 提交于 
      The invalid guest state emulation loop does not check halt_request
which causes 100% cpu loop while guest is in halt and in invalid
state, but more serious issue is that this leaves halt_request set, so
random instruction emulated by vm86 #GP exit can be interpreted
as halt which causes guest hang. Fix both problems by handling
halt_request in emulation loop.
Reported-by: NTomas Papan <tomas.papan@gmail.com>
Tested-by: NTomas Papan <tomas.papan@gmail.com>
Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com>
CC: stable@vger.kernel.org
Signed-off-by: NGleb Natapov <gleb@redhat.com>
      8d76c49e
  27. 08 5月, 2013 4 次提交
  29. 07 5月, 2013 3 次提交
  31. 06 5月, 2013 1 次提交
    • K
      xen/vcpu/pvhvm: Fix vcpu hotplugging hanging. · 7f1fc268
      由 Konrad Rzeszutek Wilk 提交于 
      If a user did:

	echo 0 > /sys/devices/system/cpu/cpu1/online
	echo 1 > /sys/devices/system/cpu/cpu1/online

we would (this a build with DEBUG enabled) get to:
smpboot: ++++++++++++++++++++=_---CPU UP  1
.. snip..
smpboot: Stack at about ffff880074c0ff44
smpboot: CPU1: has booted.

and hang. The RCU mechanism would kick in an try to IPI the CPU1
but the IPIs (and all other interrupts) would never arrive at the
CPU1. At first glance at least. A bit digging in the hypervisor
trace shows that (using xenanalyze):

[vla] d4v1 vec 243 injecting
   0.043163027 --|x d4v1 intr_window vec 243 src 5(vector) intr f3
]  0.043163639 --|x d4v1 vmentry cycles 1468
]  0.043164913 --|x d4v1 vmexit exit_reason PENDING_INTERRUPT eip ffffffff81673254
   0.043164913 --|x d4v1 inj_virq vec 243  real
  [vla] d4v1 vec 243 injecting
   0.043164913 --|x d4v1 intr_window vec 243 src 5(vector) intr f3
]  0.043165526 --|x d4v1 vmentry cycles 1472
]  0.043166800 --|x d4v1 vmexit exit_reason PENDING_INTERRUPT eip ffffffff81673254
   0.043166800 --|x d4v1 inj_virq vec 243  real
  [vla] d4v1 vec 243 injecting

there is a pending event (subsequent debugging shows it is the IPI
from the VCPU0 when smpboot.c on VCPU1 has done
"set_cpu_online(smp_processor_id(), true)") and the guest VCPU1 is
interrupted with the callback IPI (0xf3 aka 243) which ends up calling
__xen_evtchn_do_upcall.

The __xen_evtchn_do_upcall seems to do *something* but not acknowledge
the pending events. And the moment the guest does a 'cli' (that is the
ffffffff81673254 in the log above) the hypervisor is invoked again to
inject the IPI (0xf3) to tell the guest it has pending interrupts.
This repeats itself forever.

The culprit was the per_cpu(xen_vcpu, cpu) pointer. At the bootup
we set each per_cpu(xen_vcpu, cpu) to point to the
shared_info->vcpu_info[vcpu] but later on use the VCPUOP_register_vcpu_info
to register per-CPU  structures (xen_vcpu_setup).
This is used to allow events for more than 32 VCPUs and for performance
optimizations reasons.

When the user performs the VCPU hotplug we end up calling the
the xen_vcpu_setup once more. We make the hypercall which returns
-EINVAL as it does not allow multiple registration calls (and
already has re-assigned where the events are being set). We pick
the fallback case and set per_cpu(xen_vcpu, cpu) to point to the
shared_info->vcpu_info[vcpu] (which is a good fallback during bootup).
However the hypervisor is still setting events in the register
per-cpu structure (per_cpu(xen_vcpu_info, cpu)).

As such when the events are set by the hypervisor (such as timer one),
and when we iterate in __xen_evtchn_do_upcall we end up reading stale
events from the shared_info->vcpu_info[vcpu] instead of the
per_cpu(xen_vcpu_info, cpu) structures. Hence we never acknowledge the
events that the hypervisor has set and the hypervisor keeps on reminding
us to ack the events which we never do.

The fix is simple. Don't on the second time when xen_vcpu_setup is
called over-write the per_cpu(xen_vcpu, cpu) if it points to
per_cpu(xen_vcpu_info).
Acked-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
CC: stable@vger.kernel.org
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
      7f1fc268
  33. 05 5月, 2013 1 次提交
  35. 04 5月, 2013 2 次提交
  37. 03 5月, 2013 4 次提交
  39. 01 5月, 2013 1 次提交
    • S
      Kconfig: consolidate CONFIG_DEBUG_STRICT_USER_COPY_CHECKS · 446f24d1
      由 Stephen Boyd 提交于 
      The help text for this config is duplicated across the x86, parisc, and
s390 Kconfig.debug files.  Arnd Bergman noted that the help text was
slightly misleading and should be fixed to state that enabling this
option isn't a problem when using pre 4.4 gcc.

To simplify the rewording, consolidate the text into lib/Kconfig.debug
and modify it there to be more explicit about when you should say N to
this config.

Also, make the text a bit more generic by stating that this option
enables compile time checks so we can cover architectures which emit
warnings vs.  ones which emit errors.  The details of how an
architecture decided to implement the checks isn't as important as the
concept of compile time checking of copy_from_user() calls.

While we're doing this, remove all the copy_from_user_overflow() code
that's duplicated many times and place it into lib/ so that any
architecture supporting this option can get the function for free.
Signed-off-by: NStephen Boyd <sboyd@codeaurora.org>
Acked-by: NArnd Bergmann <arnd@arndb.de>
Acked-by: NIngo Molnar <mingo@kernel.org>
Acked-by: NH. Peter Anvin <hpa@zytor.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Acked-by: NHelge Deller <deller@gmx.de>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      446f24d1