1. 12 10月, 2010 13 次提交
  2. 01 10月, 2010 2 次提交
  3. 29 9月, 2010 1 次提交
  4. 25 9月, 2010 1 次提交
  5. 24 9月, 2010 1 次提交
    • R
      perf, x86: Catch spurious interrupts after disabling counters · 63e6be6d
      Robert Richter 提交于
      Some cpus still deliver spurious interrupts after disabling a
      counter. This caused 'undelivered NMI' messages. This patch
      fixes this. Introduced by:
      
        4177c42a: perf, x86: Try to handle unknown nmis with an enabled PMU
      Reported-by: NIngo Molnar <mingo@elte.hu>
      Signed-off-by: NRobert Richter <robert.richter@amd.com>
      Cc: Don Zickus <dzickus@redhat.com>
      Cc: gorcunov@gmail.com <gorcunov@gmail.com>
      Cc: fweisbec@gmail.com <fweisbec@gmail.com>
      Cc: ying.huang@intel.com <ying.huang@intel.com>
      Cc: ming.m.lin@intel.com <ming.m.lin@intel.com>
      Cc: yinghai@kernel.org <yinghai@kernel.org>
      Cc: andi@firstfloor.org <andi@firstfloor.org>
      Cc: eranian@google.com <eranian@google.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      LKML-Reference: <20100915162034.GO13563@erda.amd.com>
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      63e6be6d
  6. 23 9月, 2010 6 次提交
  7. 17 9月, 2010 1 次提交
    • F
      x86: Fix instruction breakpoint encoding · 89e45aac
      Frederic Weisbecker 提交于
      Lengths and types of breakpoints are encoded in a half byte
      into CPU registers. However when we extract these values
      and store them, we add a high half byte part to them: 0x40 to the
      length and 0x80 to the type.
      When that gets reloaded to the CPU registers, the high part
      is masked.
      
      While making the instruction breakpoints available for perf,
      I zapped that high part on instruction breakpoint encoding
      and that broke the arch -> generic translation used by ptrace
      instruction breakpoints. Writing dr7 to set an inst breakpoint
      was then failing.
      
      There is no apparent reason for these high parts so we could get
      rid of them altogether. That's an invasive change though so let's
      do that later and for now fix the problem by restoring that inst
      breakpoint high part encoding in this sole patch.
      Reported-by: NKelvie Wong <kelvie@ieee.org>
      Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
      Cc: Prasad <prasad@linux.vnet.ibm.com>
      Cc: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
      Cc: Will Deacon <will.deacon@arm.com>
      89e45aac
  8. 16 9月, 2010 3 次提交
    • S
      x86, x2apic: Simplify apic init in SMP and UP builds · fa47f7e5
      Suresh Siddha 提交于
      Move enable_IR_x2apic() inside the default_setup_apic_routing(),
      and for SMP platforms, move the default_setup_apic_routing() after
      smp_sanity_check(). This cleans up the code that tries to avoid multiple
      calls to default_setup_apic_routing() when smp_sanity_check() fails (which
      goes through the APIC_init_uniprocessor() path).
      Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
      LKML-Reference: <20100827181049.173087246@sbsiddha-MOBL3.sc.intel.com>
      Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>
      fa47f7e5
    • S
      x86, intr-remap: Remove IRTE setup duplicate code · 62a92f4c
      Suresh Siddha 提交于
      Remove IRTE setup duplicate code with prepare_irte().
      Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
      LKML-Reference: <20100827181049.095067319@sbsiddha-MOBL3.sc.intel.com>
      Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>
      62a92f4c
    • S
      x86, intr-remap: Set redirection hint in the IRTE · 75e3cfbe
      Suresh Siddha 提交于
      Currently the redirection hint in the interrupt-remapping table entry
      is set to 0, which means the remapped interrupt is directed to the
      processors listed in the destination. So in logical flat mode
      in the presence of intr-remapping, this results in a single
      interrupt multi-casted to multiple cpu's as specified by the destination
      bit mask. But what we really want is to send that interrupt to one of the cpus
      based on the lowest priority delivery mode.
      
      Set the redirection hint in the IRTE to '1' to indicate that we want
      the remapped interrupt to be directed to only one of the processors
      listed in the destination.
      
      This fixes the issue of same interrupt getting delivered to multiple cpu's
      in the logical flat mode in the presence of interrupt-remapping. While
      there is no functional issue observed with this behavior, this will
      impact performance of such configurations (<=8 cpu's using logical flat
      mode in the presence of interrupt-remapping)
      Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
      LKML-Reference: <20100827181049.013051492@sbsiddha-MOBL3.sc.intel.com>
      Cc: Weidong Han <weidong.han@intel.com>
      Cc: <stable@kernel.org> # [v2.6.32+]
      Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>
      75e3cfbe
  9. 15 9月, 2010 1 次提交
    • T
      x86: hpet: Work around hardware stupidity · 54ff7e59
      Thomas Gleixner 提交于
      This more or less reverts commits 08be9796 (x86: Force HPET
      readback_cmp for all ATI chipsets) and 30a564be (x86, hpet: Restrict
      read back to affected ATI chipsets) to the status of commit 8da854cb
      (x86, hpet: Erratum workaround for read after write of HPET
      comparator).
      
      The delta to commit 8da854cb is mostly comments and the change from
      WARN_ONCE to printk_once as we know the call path of this function
      already.
      
      This needs really in depth explanation:
      
      First of all the HPET design is a complete failure. Having a counter
      compare register which generates an interrupt on matching values
      forces the software to do at least one superfluous readback of the
      counter register.
      
      While it is nice in theory to program "absolute" time events it is
      practically useless because the timer runs at some absurd frequency
      which can never be matched to real world units. So we are forced to
      calculate a relative delta and this forces a readout of the actual
      counter value, adding the delta and programming the compare
      register. When the delta is small enough we run into the danger that
      we program a compare value which is already in the past. Due to the
      compare for equal nature of HPET we need to read back the counter
      value after writing the compare rehgister (btw. this is necessary for
      absolute timeouts as well) to make sure that we did not miss the timer
      event. We try to work around that by setting the minimum delta to a
      value which is larger than the theoretical time which elapses between
      the counter readout and the compare register write, but that's only
      true in theory. A NMI or SMI which hits between the readout and the
      write can easily push us beyond that limit. This would result in
      waiting for the next HPET timer interrupt until the 32bit wraparound
      of the counter happens which takes about 306 seconds.
      
      So we designed the next event function to look like:
      
         match = read_cnt() + delta;
         write_compare_ref(match);
         return read_cnt() < match ? 0 : -ETIME;
      
      At some point we got into trouble with certain ATI chipsets. Even the
      above "safe" procedure failed. The reason was that the write to the
      compare register was delayed probably for performance reasons. The
      theory was that they wanted to avoid the synchronization of the write
      with the HPET clock, which is understandable. So the write does not
      hit the compare register directly instead it goes to some intermediate
      register which is copied to the real compare register in sync with the
      HPET clock. That opens another window for hitting the dreaded "wait
      for a wraparound" problem.
      
      To work around that "optimization" we added a read back of the compare
      register which either enforced the update of the just written value or
      just delayed the readout of the counter enough to avoid the issue. We
      unfortunately never got any affirmative info from ATI/AMD about this.
      
      One thing is sure, that we nuked the performance "optimization" that
      way completely and I'm pretty sure that the result is worse than
      before some HW folks came up with those.
      
      Just for paranoia reasons I added a check whether the read back
      compare register value was the same as the value we wrote right
      before. That paranoia check triggered a couple of years after it was
      added on an Intel ICH9 chipset. Venki added a workaround (commit
      8da854cb) which was reading the compare register twice when the first
      check failed. We considered this to be a penalty in general and
      restricted the readback (thus the wasted CPU cycles) to the known to
      be affected ATI chipsets.
      
      This turned out to be a utterly wrong decision. 2.6.35 testers
      experienced massive problems and finally one of them bisected it down
      to commit 30a564be which spured some further investigation.
      
      Finally we got confirmation that the write to the compare register can
      be delayed by up to two HPET clock cycles which explains the problems
      nicely. All we can do about this is to go back to Venki's initial
      workaround in a slightly modified version.
      
      Just for the record I need to say, that all of this could have been
      avoided if hardware designers and of course the HPET committee would
      have thought about the consequences for a split second. It's out of my
      comprehension why designing a working timer is so hard. There are two
      ways to achieve it:
      
       1) Use a counter wrap around aware compare_reg <= counter_reg
          implementation instead of the easy compare_reg == counter_reg
      
          Downsides:
      
      	- It needs more silicon.
      
      	- It needs a readout of the counter to apply a relative
      	  timeout. This is necessary as the counter does not run in
      	  any useful (and adjustable) frequency and there is no
      	  guarantee that the counter which is used for timer events is
      	  the same which is used for reading the actual time (and
      	  therefor for calculating the delta)
      
          Upsides:
      
      	- None
      
        2) Use a simple down counter for relative timer events
      
          Downsides:
      
      	- Absolute timeouts are not possible, which is not a problem
      	  at all in the context of an OS and the expected
      	  max. latencies/jitter (also see Downsides of #1)
      
         Upsides:
      
      	- It needs less or equal silicon.
      
      	- It works ALWAYS
      
      	- It is way faster than a compare register based solution (One
      	  write versus one write plus at least one and up to four
      	  reads)
      
      I would not be so grumpy about all of this, if I would not have been
      ignored for many years when pointing out these flaws to various
      hardware folks. I really hate timers (at least those which seem to be
      designed by janitors).
      
      Though finally we got a reasonable explanation plus a solution and I
      want to thank all the folks involved in chasing it down and providing
      valuable input to this.
      Bisected-by: NNix <nix@esperi.org.uk>
      Reported-by: NArtur Skawina <art.08.09@gmail.com>
      Reported-by: NDamien Wyart <damien.wyart@free.fr>
      Reported-by: NJohn Drescher <drescherjm@gmail.com>
      Cc: Venkatesh Pallipadi <venki@google.com>
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: H. Peter Anvin <hpa@zytor.com>
      Cc: Arjan van de Ven <arjan@linux.intel.com>
      Cc: Andreas Herrmann <andreas.herrmann3@amd.com>
      Cc: Borislav Petkov <borislav.petkov@amd.com>
      Cc: stable@kernel.org
      Acked-by: NSuresh Siddha <suresh.b.siddha@intel.com>
      Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
      54ff7e59
  10. 11 9月, 2010 2 次提交
  11. 10 9月, 2010 1 次提交
  12. 08 9月, 2010 1 次提交
  13. 05 9月, 2010 1 次提交
    • A
      x86, mcheck: Avoid duplicate sysfs links/files for thresholding banks · 1389298f
      Andreas Herrmann 提交于
      kobject_add_internal failed for threshold_bank2 with -EEXIST,
      don't try to register things with the same name in the same
      directory:
      
        Pid: 1, comm: swapper Tainted: G        W  2.6.31 #1
        Call Trace:
        [<ffffffff81161b07>] ? kobject_add_internal+0x156/0x180
        [<ffffffff81161cc0>] ? kobject_add+0x66/0x6b
        [<ffffffff81161793>] ? kobject_init+0x42/0x82
        [<ffffffff81161cf9>] ? kobject_create_and_add+0x34/0x63
        [<ffffffff81393963>] ? threshold_create_bank+0x14f/0x259
        [<ffffffff8139310a>] ? mce_create_device+0x8d/0x1b8
        [<ffffffff81646497>] ? threshold_init_device+0x3f/0x80
        [<ffffffff81646458>] ? threshold_init_device+0x0/0x80
        [<ffffffff81009050>] ? do_one_initcall+0x4f/0x143
        [<ffffffff816413a0>] ? kernel_init+0x14c/0x1a2
        [<ffffffff8100c8da>] ? child_rip+0xa/0x20
        [<ffffffff81641254>] ? kernel_init+0x0/0x1a2
        [<ffffffff8100c8d0>] ? child_rip+0x0/0x20
        kobject_create_and_add: kobject_add error: -17
      
      (Probably the for_each_cpu loop should be entirely removed.)
      Signed-off-by: NAndreas Herrmann <andreas.herrmann3@amd.com>
      LKML-Reference: <20100827092006.GB5348@loge.amd.com>
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      1389298f
  14. 03 9月, 2010 3 次提交
    • R
      perf, x86: Try to handle unknown nmis with an enabled PMU · 4177c42a
      Robert Richter 提交于
      When the PMU is enabled it is valid to have unhandled nmis, two
      events could trigger 'simultaneously' raising two back-to-back
      NMIs. If the first NMI handles both, the latter will be empty
      and daze the CPU.
      
      The solution to avoid an 'unknown nmi' massage in this case was
      simply to stop the nmi handler chain when the PMU is enabled by
      stating the nmi was handled. This has the drawback that a) we
      can not detect unknown nmis anymore, and b) subsequent nmi
      handlers are not called.
      
      This patch addresses this. Now, we check this unknown NMI if it
      could be a PMU back-to-back NMI. Otherwise we pass it and let
      the kernel handle the unknown nmi.
      
      This is a debug log:
      
       cpu #6, nmi #32333, skip_nmi #32330, handled = 1, time = 1934364430
       cpu #6, nmi #32334, skip_nmi #32330, handled = 1, time = 1934704616
       cpu #6, nmi #32335, skip_nmi #32336, handled = 2, time = 1936032320
       cpu #6, nmi #32336, skip_nmi #32336, handled = 0, time = 1936034139
       cpu #6, nmi #32337, skip_nmi #32336, handled = 1, time = 1936120100
       cpu #6, nmi #32338, skip_nmi #32336, handled = 1, time = 1936404607
       cpu #6, nmi #32339, skip_nmi #32336, handled = 1, time = 1937983416
       cpu #6, nmi #32340, skip_nmi #32341, handled = 2, time = 1938201032
       cpu #6, nmi #32341, skip_nmi #32341, handled = 0, time = 1938202830
       cpu #6, nmi #32342, skip_nmi #32341, handled = 1, time = 1938443743
       cpu #6, nmi #32343, skip_nmi #32341, handled = 1, time = 1939956552
       cpu #6, nmi #32344, skip_nmi #32341, handled = 1, time = 1940073224
       cpu #6, nmi #32345, skip_nmi #32341, handled = 1, time = 1940485677
       cpu #6, nmi #32346, skip_nmi #32347, handled = 2, time = 1941947772
       cpu #6, nmi #32347, skip_nmi #32347, handled = 1, time = 1941949818
       cpu #6, nmi #32348, skip_nmi #32347, handled = 0, time = 1941951591
       Uhhuh. NMI received for unknown reason 00 on CPU 6.
       Do you have a strange power saving mode enabled?
       Dazed and confused, but trying to continue
      
      Deltas:
      
       nmi #32334 340186
       nmi #32335 1327704
       nmi #32336 1819      <<<< back-to-back nmi [1]
       nmi #32337 85961
       nmi #32338 284507
       nmi #32339 1578809
       nmi #32340 217616
       nmi #32341 1798      <<<< back-to-back nmi [2]
       nmi #32342 240913
       nmi #32343 1512809
       nmi #32344 116672
       nmi #32345 412453
       nmi #32346 1462095   <<<< 1st nmi (standard) handling 2 counters
       nmi #32347 2046      <<<< 2nd nmi (back-to-back) handling one
       counter nmi #32348 1773      <<<< 3rd nmi (back-to-back)
       handling no counter! [3]
      
      For  back-to-back nmi detection there are the following rules:
      
      The PMU nmi handler was handling more than one counter and no
      counter was handled in the subsequent nmi (see [1] and [2]
      above).
      
      There is another case if there are two subsequent back-to-back
      nmis [3]. The 2nd is detected as back-to-back because the first
      handled more than one counter. If the second handles one counter
      and the 3rd handles nothing, we drop the 3rd nmi because it
      could be a back-to-back nmi.
      Signed-off-by: NRobert Richter <robert.richter@amd.com>
      Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
      [ renamed nmi variable to pmu_nmi to avoid clash with .nmi in entry.S ]
      Signed-off-by: NDon Zickus <dzickus@redhat.com>
      Cc: peterz@infradead.org
      Cc: gorcunov@gmail.com
      Cc: fweisbec@gmail.com
      Cc: ying.huang@intel.com
      Cc: ming.m.lin@intel.com
      Cc: eranian@google.com
      LKML-Reference: <1283454469-1909-3-git-send-email-dzickus@redhat.com>
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      4177c42a
    • P
      perf, x86: Fix handle_irq return values · de725dec
      Peter Zijlstra 提交于
      Now that we rely on the number of handled overflows, ensure all
      handle_irq implementations actually return the right number.
      Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
      Signed-off-by: NDon Zickus <dzickus@redhat.com>
      Cc: peterz@infradead.org
      Cc: robert.richter@amd.com
      Cc: gorcunov@gmail.com
      Cc: fweisbec@gmail.com
      Cc: ying.huang@intel.com
      Cc: ming.m.lin@intel.com
      Cc: eranian@google.com
      LKML-Reference: <1283454469-1909-4-git-send-email-dzickus@redhat.com>
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      de725dec
    • D
      perf, x86: Fix accidentally ack'ing a second event on intel perf counter · 2e556b5b
      Don Zickus 提交于
      During testing of a patch to stop having the perf subsytem
      swallow nmis, it was uncovered that Nehalem boxes were randomly
      getting unknown nmis when using the perf tool.
      
      Moving the ack'ing of the PMI closer to when we get the status
      allows the hardware to properly re-set the PMU bit signaling
      another PMI was triggered during the processing of the first
      PMI.  This allows the new logic for dealing with the
      shortcomings of multiple PMIs to handle the extra NMI by
      'eat'ing it later.
      
      Now one can wonder why are we getting a second PMI when we
      disable all the PMUs in the begining of the NMI handler to
      prevent such a case, for that I do not know.  But I know the fix
      below helps deal with this quirk.
      
      Tested on multiple Nehalems where the problem was occuring.
      With the patch, the code now loops a second time to handle the
      second PMI (whereas before it was not).
      Signed-off-by: NDon Zickus <dzickus@redhat.com>
      Cc: peterz@infradead.org
      Cc: robert.richter@amd.com
      Cc: gorcunov@gmail.com
      Cc: fweisbec@gmail.com
      Cc: ying.huang@intel.com
      Cc: ming.m.lin@intel.com
      Cc: eranian@google.com
      LKML-Reference: <1283454469-1909-2-git-send-email-dzickus@redhat.com>
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      2e556b5b
  15. 25 8月, 2010 2 次提交
  16. 21 8月, 2010 1 次提交