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  1. Jul 27, 2015
  2. Jul 26, 2015
    • Thomas Gleixner's avatar
      x86/mm/pat: Revert 'Adjust default caching mode translation tables' · 1a4e8795
      Thomas Gleixner authored
      
      
      Toshi explains:
      
      "No, the default values need to be set to the fallback types,
       i.e. minimal supported mode.  For WC and WT, UC is the fallback type.
      
       When PAT is disabled, pat_init() does update the tables below to
       enable WT per the default BIOS setup.  However, when PAT is enabled,
       but CPU has PAT -errata, WT falls back to UC per the default values."
      
      Revert: ca1fec58 'x86/mm/pat: Adjust default caching mode translation tables'
      Requested-by: default avatarToshi Kani <toshi.kani@hp.com>
      Cc: Jan Beulich <jbeulich@suse.de>
      Link: http://lkml.kernel.org/r/1437577776.3214.252.camel@hp.com
      
      
      Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
      1a4e8795
    • Matt Fleming's avatar
      perf/x86/intel/cqm: Return cached counter value from IRQ context · 2c534c0d
      Matt Fleming authored
      
      
      Peter reported the following potential crash which I was able to
      reproduce with his test program,
      
      [  148.765788] ------------[ cut here ]------------
      [  148.765796] WARNING: CPU: 34 PID: 2840 at kernel/smp.c:417 smp_call_function_many+0xb6/0x260()
      [  148.765797] Modules linked in:
      [  148.765800] CPU: 34 PID: 2840 Comm: perf Not tainted 4.2.0-rc1+ #4
      [  148.765803]  ffffffff81cdc398 ffff88085f105950 ffffffff818bdfd5 0000000000000007
      [  148.765805]  0000000000000000 ffff88085f105990 ffffffff810e413a 0000000000000000
      [  148.765807]  ffffffff82301080 0000000000000022 ffffffff8107f640 ffffffff8107f640
      [  148.765809] Call Trace:
      [  148.765810]  <NMI>  [<ffffffff818bdfd5>] dump_stack+0x45/0x57
      [  148.765818]  [<ffffffff810e413a>] warn_slowpath_common+0x8a/0xc0
      [  148.765822]  [<ffffffff8107f640>] ? intel_cqm_stable+0x60/0x60
      [  148.765824]  [<ffffffff8107f640>] ? intel_cqm_stable+0x60/0x60
      [  148.765825]  [<ffffffff810e422a>] warn_slowpath_null+0x1a/0x20
      [  148.765827]  [<ffffffff811613f6>] smp_call_function_many+0xb6/0x260
      [  148.765829]  [<ffffffff8107f640>] ? intel_cqm_stable+0x60/0x60
      [  148.765831]  [<ffffffff81161748>] on_each_cpu_mask+0x28/0x60
      [  148.765832]  [<ffffffff8107f6ef>] intel_cqm_event_count+0x7f/0xe0
      [  148.765836]  [<ffffffff811cdd35>] perf_output_read+0x2a5/0x400
      [  148.765839]  [<ffffffff811d2e5a>] perf_output_sample+0x31a/0x590
      [  148.765840]  [<ffffffff811d333d>] ? perf_prepare_sample+0x26d/0x380
      [  148.765841]  [<ffffffff811d3497>] perf_event_output+0x47/0x60
      [  148.765843]  [<ffffffff811d36c5>] __perf_event_overflow+0x215/0x240
      [  148.765844]  [<ffffffff811d4124>] perf_event_overflow+0x14/0x20
      [  148.765847]  [<ffffffff8107e7f4>] intel_pmu_handle_irq+0x1d4/0x440
      [  148.765849]  [<ffffffff811d07a6>] ? __perf_event_task_sched_in+0x36/0xa0
      [  148.765853]  [<ffffffff81219bad>] ? vunmap_page_range+0x19d/0x2f0
      [  148.765854]  [<ffffffff81219d11>] ? unmap_kernel_range_noflush+0x11/0x20
      [  148.765859]  [<ffffffff814ce6fe>] ? ghes_copy_tofrom_phys+0x11e/0x2a0
      [  148.765863]  [<ffffffff8109e5db>] ? native_apic_msr_write+0x2b/0x30
      [  148.765865]  [<ffffffff8109e44d>] ? x2apic_send_IPI_self+0x1d/0x20
      [  148.765869]  [<ffffffff81065135>] ? arch_irq_work_raise+0x35/0x40
      [  148.765872]  [<ffffffff811c8d86>] ? irq_work_queue+0x66/0x80
      [  148.765875]  [<ffffffff81075306>] perf_event_nmi_handler+0x26/0x40
      [  148.765877]  [<ffffffff81063ed9>] nmi_handle+0x79/0x100
      [  148.765879]  [<ffffffff81064422>] default_do_nmi+0x42/0x100
      [  148.765880]  [<ffffffff81064563>] do_nmi+0x83/0xb0
      [  148.765884]  [<ffffffff818c7c0f>] end_repeat_nmi+0x1e/0x2e
      [  148.765886]  [<ffffffff811d07a6>] ? __perf_event_task_sched_in+0x36/0xa0
      [  148.765888]  [<ffffffff811d07a6>] ? __perf_event_task_sched_in+0x36/0xa0
      [  148.765890]  [<ffffffff811d07a6>] ? __perf_event_task_sched_in+0x36/0xa0
      [  148.765891]  <<EOE>>  [<ffffffff8110ab66>] finish_task_switch+0x156/0x210
      [  148.765898]  [<ffffffff818c1671>] __schedule+0x341/0x920
      [  148.765899]  [<ffffffff818c1c87>] schedule+0x37/0x80
      [  148.765903]  [<ffffffff810ae1af>] ? do_page_fault+0x2f/0x80
      [  148.765905]  [<ffffffff818c1f4a>] schedule_user+0x1a/0x50
      [  148.765907]  [<ffffffff818c666c>] retint_careful+0x14/0x32
      [  148.765908] ---[ end trace e33ff2be78e14901 ]---
      
      The CQM task events are not safe to be called from within interrupt
      context because they require performing an IPI to read the counter value
      on all sockets. And performing IPIs from within IRQ context is a
      "no-no".
      
      Make do with the last read counter value currently event in
      event->count when we're invoked in this context.
      
      Reported-by: default avatarPeter Zijlstra <peterz@infradead.org>
      Signed-off-by: default avatarMatt Fleming <matt.fleming@intel.com>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Vikas Shivappa <vikas.shivappa@intel.com>
      Cc: Kanaka Juvva <kanaka.d.juvva@intel.com>
      Cc: Will Auld <will.auld@intel.com>
      Cc: <stable@vger.kernel.org>
      Link: http://lkml.kernel.org/r/1437490509-15373-1-git-send-email-matt@codeblueprint.co.uk
      
      
      Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
      2c534c0d
  3. Jul 24, 2015
  4. Jul 23, 2015
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