1. 07 Mar, 2014 14 commits
  2. 28 Feb, 2014 8 commits
  3. 17 Feb, 2014 11 commits
    • Gavin Shan's avatar
      powerpc/eeh: Disable EEH on reboot · 66f9af83
      Gavin Shan authored
      We possiblly detect EEH errors during reboot, particularly in kexec
      path, but it's impossible for device drivers and EEH core to handle
      or recover them properly.
      
      The patch registers one reboot notifier for EEH and disable EEH
      subsystem during reboot. That means the EEH errors is going to be
      cleared by hardware reset or second kernel during early stage of
      PCI probe.
      Signed-off-by: default avatarGavin Shan <shangw@linux.vnet.ibm.com>
      Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
      66f9af83
    • Gavin Shan's avatar
      powerpc/eeh: Cleanup on eeh_subsystem_enabled · 2ec5a0ad
      Gavin Shan authored
      The patch cleans up variable eeh_subsystem_enabled so that we needn't
      refer the variable directly from external. Instead, we will use
      function eeh_enabled() and eeh_set_enable() to operate the variable.
      Signed-off-by: default avatarGavin Shan <shangw@linux.vnet.ibm.com>
      Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
      2ec5a0ad
    • Gavin Shan's avatar
      powerpc/powernv: Rework EEH reset · 5b2e198e
      Gavin Shan authored
      When doing reset in order to recover the affected PE, we issue
      hot reset on PE primary bus if it's not root bus. Otherwise, we
      issue hot or fundamental reset on root port or PHB accordingly.
      For the later case, we didn't cover the situation where PE only
      includes root port and it potentially causes kernel crash upon
      EEH error to the PE.
      
      The patch reworks the logic of EEH reset to improve the code
      readability and also avoid the kernel crash.
      
      Cc: stable@vger.kernel.org
      Reported-by: default avatarThadeu Lima de Souza Cascardo <cascardo@linux.vnet.ibm.com>
      Signed-off-by: default avatarGavin Shan <shangw@linux.vnet.ibm.com>
      Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
      5b2e198e
    • Anton Blanchard's avatar
      powerpc: Use unstripped VDSO image for more accurate profiling data · 24b659a1
      Anton Blanchard authored
      We are seeing a lot of hits in the VDSO that are not resolved by perf.
      A while(1) gettimeofday() loop shows the issue:
      
      27.64%  [vdso]  [.] 0x000000000000060c
      22.57%  [vdso]  [.] 0x0000000000000628
      16.88%  [vdso]  [.] 0x0000000000000610
      12.39%  [vdso]  [.] __kernel_gettimeofday
       6.09%  [vdso]  [.] 0x00000000000005f8
       3.58%  test    [.] 00000037.plt_call.gettimeofday@@GLIBC_2.18
       2.94%  [vdso]  [.] __kernel_datapage_offset
       2.90%  test    [.] main
      
      We are using a stripped VDSO image which means only symbols with
      relocation info can be resolved. There isn't a lot of point to
      stripping the VDSO, the debug info is only about 1kB:
      
      4680 arch/powerpc/kernel/vdso64/vdso64.so
      5815 arch/powerpc/kernel/vdso64/vdso64.so.dbg
      
      By using the unstripped image, we can resolve all the symbols in the
      VDSO and the perf profile data looks much better:
      
      76.53%  [vdso]  [.] __do_get_tspec
      12.20%  [vdso]  [.] __kernel_gettimeofday
       5.05%  [vdso]  [.] __get_datapage
       3.20%  test    [.] main
       2.92%  test    [.] 00000037.plt_call.gettimeofday@@GLIBC_2.18
      Signed-off-by: default avatarAnton Blanchard <anton@samba.org>
      Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
      24b659a1
    • Anton Blanchard's avatar
      powerpc: Link VDSOs at 0x0 · a0a4419e
      Anton Blanchard authored
      perf is failing to resolve symbols in the VDSO. A while (1)
      gettimeofday() loop shows:
      
      93.99%  [vdso]  [.] 0x00000000000005e0
       3.12%  test    [.] 00000037.plt_call.gettimeofday@@GLIBC_2.18
       2.81%  test    [.] main
      
      The reason for this is that we are linking our VDSO shared libraries
      at 1MB, which is a little weird. Even though this is uncommon, Alan
      points out that it is valid and we should probably fix perf userspace.
      
      Regardless, I can't see a reason why we are doing this. The code
      is all position independent and we never rely on the VDSO ending
      up at 1M (and we never place it there on 64bit tasks).
      
      Changing our link address to 0x0 fixes perf VDSO symbol resolution:
      
      73.18%  [vdso]  [.] 0x000000000000060c
      12.39%  [vdso]  [.] __kernel_gettimeofday
       3.58%  test    [.] 00000037.plt_call.gettimeofday@@GLIBC_2.18
       2.94%  [vdso]  [.] __kernel_datapage_offset
       2.90%  test    [.] main
      
      We still have some local symbol resolution issues that will be
      fixed in a subsequent patch.
      Signed-off-by: default avatarAnton Blanchard <anton@samba.org>
      Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
      a0a4419e
    • Aneesh Kumar K.V's avatar
      mm: Use ptep/pmdp_set_numa() for updating _PAGE_NUMA bit · 56eecdb9
      Aneesh Kumar K.V authored
      Archs like ppc64 doesn't do tlb flush in set_pte/pmd functions when using
      a hash table MMU for various reasons (the flush is handled as part of
      the PTE modification when necessary).
      
      ppc64 thus doesn't implement flush_tlb_range for hash based MMUs.
      
      Additionally ppc64 require the tlb flushing to be batched within ptl locks.
      
      The reason to do that is to ensure that the hash page table is in sync with
      linux page table.
      
      We track the hpte index in linux pte and if we clear them without flushing
      hash and drop the ptl lock, we can have another cpu update the pte and can
      end up with duplicate entry in the hash table, which is fatal.
      
      We also want to keep set_pte_at simpler by not requiring them to do hash
      flush for performance reason. We do that by assuming that set_pte_at() is
      never *ever* called on a PTE that is already valid.
      
      This was the case until the NUMA code went in which broke that assumption.
      
      Fix that by introducing a new pair of helpers to set _PAGE_NUMA in a
      way similar to ptep/pmdp_set_wrprotect(), with a generic implementation
      using set_pte_at() and a powerpc specific one using the appropriate
      mechanism needed to keep the hash table in sync.
      Acked-by: default avatarMel Gorman <mgorman@suse.de>
      Reviewed-by: default avatarRik van Riel <riel@redhat.com>
      Signed-off-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
      Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
      56eecdb9
    • Aneesh Kumar K.V's avatar
    • Aneesh Kumar K.V's avatar
      powerpc/mm: Add new "set" flag argument to pte/pmd update function · 88247e8d
      Aneesh Kumar K.V authored
      pte_update() is a powerpc-ism used to change the bits of a PTE
      when the access permission is being restricted (a flush is
      potentially needed).
      
      It uses atomic operations on when needed and handles the hash
      synchronization on hash based processors.
      
      It is currently only used to clear PTE bits and so the current
      implementation doesn't provide a way to also set PTE bits.
      
      The new _PAGE_NUMA bit, when set, is actually restricting access
      so it must use that function too, so this change adds the ability
      for pte_update() to also set bits.
      
      We will use this later to set the _PAGE_NUMA bit.
      Acked-by: default avatarMel Gorman <mgorman@suse.de>
      Acked-by: default avatarRik van Riel <riel@redhat.com>
      Signed-off-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
      Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
      88247e8d
    • Kleber Sacilotto de Souza's avatar
      powerpc/pseries: Add Gen3 definitions for PCIE link speed · 49d9684a
      Kleber Sacilotto de Souza authored
      Rev3 of the PCI Express Base Specification defines a Supported Link
      Speeds Vector where the bit definitions within this field are:
      
      Bit 0 - 2.5 GT/s
      Bit 1 - 5.0 GT/s
      Bit 2 - 8.0 GT/s
      
      This vector definition is used by the platform firmware to export the
      maximum and current link speeds of the PCI bus via the
      "ibm,pcie-link-speed-stats" device-tree property.
      
      This patch updates pseries_root_bridge_prepare() to detect Gen3
      speed buses (defined by 0x04).
      Signed-off-by: default avatarKleber Sacilotto de Souza <klebers@linux.vnet.ibm.com>
      Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
      49d9684a
    • Kleber Sacilotto de Souza's avatar
      powerpc/pseries: Fix regression on PCI link speed · b020cc6c
      Kleber Sacilotto de Souza authored
      Commit 5091f0c9 (powerpc/pseries: Fix PCIE link speed endian issue)
      introduced a regression on the PCI link speed detection using the
      device-tree property. The ibm,pcie-link-speed-stats property is composed
      of two 32-bit integers, the first one being the maxinum link speed and
      the second the current link speed. The changes introduced by the
      aforementioned commit are considering just the first integer.
      
      Fix this issue by changing how the property is accessed, using the
      helper functions to properly access the array of values. The explicit
      byte swapping is not needed anymore here, since it's done by the helper
      functions.
      Signed-off-by: default avatarKleber Sacilotto de Souza <klebers@linux.vnet.ibm.com>
      Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
      b020cc6c
    • Kevin Hao's avatar
      powerpc: Set the correct ksp_limit on ppc32 when switching to irq stack · 1a18a664
      Kevin Hao authored
      Guenter Roeck has got the following call trace on a p2020 board:
        Kernel stack overflow in process eb3e5a00, r1=eb79df90
        CPU: 0 PID: 2838 Comm: ssh Not tainted 3.13.0-rc8-juniper-00146-g19eca00 #4
        task: eb3e5a00 ti: c0616000 task.ti: ef440000
        NIP: c003a420 LR: c003a410 CTR: c0017518
        REGS: eb79dee0 TRAP: 0901   Not tainted (3.13.0-rc8-juniper-00146-g19eca00)
        MSR: 00029000 <CE,EE,ME>  CR: 24008444  XER: 00000000
        GPR00: c003a410 eb79df90 eb3e5a00 00000000 eb05d900 00000001 65d87646 00000000
        GPR08: 00000000 020b8000 00000000 00000000 44008442
        NIP [c003a420] __do_softirq+0x94/0x1ec
        LR [c003a410] __do_softirq+0x84/0x1ec
        Call Trace:
        [eb79df90] [c003a410] __do_softirq+0x84/0x1ec (unreliable)
        [eb79dfe0] [c003a970] irq_exit+0xbc/0xc8
        [eb79dff0] [c000cc1c] call_do_irq+0x24/0x3c
        [ef441f20] [c00046a8] do_IRQ+0x8c/0xf8
        [ef441f40] [c000e7f4] ret_from_except+0x0/0x18
        --- Exception: 501 at 0xfcda524
            LR = 0x10024900
        Instruction dump:
        7c781b78 3b40000a 3a73b040 543c0024 3a800000 3b3913a0 7ef5bb78 48201bf9
        5463103a 7d3b182e 7e89b92e 7c008146 <3ba00000> 7e7e9b78 48000014 57fff87f
        Kernel panic - not syncing: kernel stack overflow
        CPU: 0 PID: 2838 Comm: ssh Not tainted 3.13.0-rc8-juniper-00146-g19eca00 #4
        Call Trace:
      
      The reason is that we have used the wrong register to calculate the
      ksp_limit in commit cbc9565e (powerpc: Remove ksp_limit on ppc64).
      Just fix it.
      
      As suggested by Benjamin Herrenschmidt, also add the C prototype of the
      function in the comment in order to avoid such kind of errors in the
      future.
      
      Cc: stable@vger.kernel.org # 3.12
      Reported-by: default avatarGuenter Roeck <linux@roeck-us.net>
      Tested-by: default avatarGuenter Roeck <linux@roeck-us.net>
      Signed-off-by: default avatarKevin Hao <haokexin@gmail.com>
      Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
      1a18a664
  4. 11 Feb, 2014 7 commits
    • Benjamin Herrenschmidt's avatar
      powerpc/powernv: Add iommu DMA bypass support for IODA2 · cd15b048
      Benjamin Herrenschmidt authored
      This patch adds the support for to create a direct iommu "bypass"
      window on IODA2 bridges (such as Power8) allowing to bypass iommu
      page translation completely for 64-bit DMA capable devices, thus
      significantly improving DMA performances.
      
      Additionally, this adds a hook to the struct iommu_table so that
      the IOMMU API / VFIO can disable the bypass when external ownership
      is requested, since in that case, the device will be used by an
      environment such as userspace or a KVM guest which must not be
      allowed to bypass translations.
      Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
      cd15b048
    • Anton Blanchard's avatar
      powerpc: Fix endian issues in kexec and crash dump code · ea961a82
      Anton Blanchard authored
      We expose a number of OF properties in the kexec and crash dump code
      and these need to be big endian.
      
      Cc: stable@vger.kernel.org # v3.13
      Signed-off-by: default avatarAnton Blanchard <anton@samba.org>
      Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
      ea961a82
    • Kevin Hao's avatar
      powerpc/ppc32: Fix the bug in the init of non-base exception stack for UP · 04a34113
      Kevin Hao authored
      We would allocate one specific exception stack for each kind of
      non-base exceptions for every CPU. For ppc32 the CPU hard ID is
      used as the subscript to get the specific exception stack for
      one CPU. But for an UP kernel, there is only one element in the
      each kind of exception stack array. We would get stuck if the
      CPU hard ID is not equal to '0'. So in this case we should use the
      subscript '0' no matter what the CPU hard ID is.
      Signed-off-by: default avatarKevin Hao <haokexin@gmail.com>
      Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
      04a34113
    • Michael Ellerman's avatar
      powerpc/xmon: Don't signal we've entered until we're finished printing · d2b496e5
      Michael Ellerman authored
      Currently we set our cpu's bit in cpus_in_xmon, and then we take the
      output lock and print the exception information.
      
      This can race with the master cpu entering the command loop and printing
      the backtrace. The result is that the backtrace gets garbled with
      another cpu's exception print out.
      
      Fix it by delaying the set of cpus_in_xmon until we are finished
      printing.
      Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
      d2b496e5
    • Michael Ellerman's avatar
      powerpc/xmon: Fix timeout loop in get_output_lock() · 15075897
      Michael Ellerman authored
      As far as I can tell, our 70s era timeout loop in get_output_lock() is
      generating no code.
      
      This leads to the hostile takeover happening more or less simultaneously
      on all cpus. The result is "interesting", some example output that is
      more readable than most:
      
          cpu 0x1: Vector: 100 (Scypsut e0mx bR:e setV)e catto xc0p:u[ c 00
          c0:0  000t0o0V0erc0td:o5 rfc28050000]0c00 0 0  0 6t(pSrycsV1ppuot
          uxe 1m 2 0Rx21e3:0s0ce000c00000t00)00 60602oV2SerucSayt0y 0p 1sxs
      
      Fix it by using udelay() in the timeout loop. The wait time and check
      frequency are arbitrary, but seem to work OK. We already rely on
      udelay() working so this is not a new dependency.
      Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
      15075897
    • Michael Ellerman's avatar
      powerpc/xmon: Don't loop forever in get_output_lock() · 730efb61
      Michael Ellerman authored
      If we enter with xmon_speaker != 0 we skip the first cmpxchg(), we also
      skip the while loop because xmon_speaker != last_speaker (0) - meaning we
      skip the second cmpxchg() also.
      
      Following that code path the compiler sees no memory barriers and so is
      within its rights to never reload xmon_speaker. The end result is we loop
      forever.
      
      This manifests as all cpus being in xmon ('c' command), but they refuse
      to take control when you switch to them ('c x' for cpu # x).
      
      I have seen this deadlock in practice and also checked the generated code to
      confirm this is what's happening.
      
      The simplest fix is just to always try the cmpxchg().
      Signed-off-by: default avatarMichael Ellerman <michael@ellerman.id.au>
      Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
      730efb61
    • Anshuman Khandual's avatar
      powerpc/perf: Configure BHRB filter before enabling PMU interrupts · b4d6c06c
      Anshuman Khandual authored
      Right now the config_bhrb() PMU specific call happens after
      write_mmcr0(), which actually enables the PMU for event counting and
      interrupts. So there is a small window of time where the PMU and BHRB
      runs without the required HW branch filter (if any) enabled in BHRB.
      
      This can cause some of the branch samples to be collected through BHRB
      without any filter applied and hence affects the correctness of
      the results. This patch moves the BHRB config function call before
      enabling interrupts.
      
      Here are some data points captured via trace prints which depicts how we
      could get PMU interrupts with BHRB filter NOT enabled with a standard
      perf record command line (asking for branch record information as well).
      
          $ perf record -j any_call ls
      
      Before the patch:-
      
          ls-1962  [003] d...  2065.299590: .perf_event_interrupt: MMCRA: 40000000000
          ls-1962  [003] d...  2065.299603: .perf_event_interrupt: MMCRA: 40000000000
          ...
      
          All the PMU interrupts before this point did not have the requested
          HW branch filter enabled in the MMCRA.
      
          ls-1962  [003] d...  2065.299647: .perf_event_interrupt: MMCRA: 40040000000
          ls-1962  [003] d...  2065.299662: .perf_event_interrupt: MMCRA: 40040000000
      
      After the patch:-
      
          ls-1850  [008] d...   190.311828: .perf_event_interrupt: MMCRA: 40040000000
          ls-1850  [008] d...   190.311848: .perf_event_interrupt: MMCRA: 40040000000
      
          All the PMU interrupts have the requested HW BHRB branch filter
          enabled in MMCRA.
      Signed-off-by: default avatarAnshuman Khandual <khandual@linux.vnet.ibm.com>
      [mpe: Fixed up whitespace and cleaned up changelog]
      Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
      b4d6c06c