1. 17 12月, 2016 1 次提交
  2. 30 11月, 2016 2 次提交
    • I
      sched/x86: Make CONFIG_SCHED_MC_PRIO=y easier to enable · 0a21fc12
      Ingo Molnar 提交于
      Right now CONFIG_SCHED_MC_PRIO has X86_INTEL_PSTATE as a dependency,
      which is not enabled by default and which hides the CONFIG_SCHED_MC_PRIO
      hardware-enabling feature.
      
      Select X86_INTEL_PSTATE instead, plus its dependency (CPU_FREQ), if the
      user enables CONFIG_SCHED_MC_PRIO=y.
      
      (Also align the CONFIG_SCHED_MC_PRIO Kconfig help text in standard style.)
      
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Tim Chen <tim.c.chen@linux.intel.com>
      Cc: bp@suse.de
      Cc: jolsa@redhat.com
      Cc: linux-acpi@vger.kernel.org
      Cc: linux-pm@vger.kernel.org
      Cc: rjw@rjwysocki.net
      Cc: linux-kernel@vger.kernel.org
      Signed-off-by: NIngo Molnar <mingo@kernel.org>
      0a21fc12
    • T
      sched/x86: Change CONFIG_SCHED_ITMT to CONFIG_SCHED_MC_PRIO · de966cf4
      Tim Chen 提交于
      Rename CONFIG_SCHED_ITMT for Intel Turbo Boost Max Technology 3.0
      to CONFIG_SCHED_MC_PRIO.  This makes the configuration extensible
      in future to other architectures that wish to similarly establish
      CPU core priorities support in the scheduler.
      
      The description in Kconfig is updated to reflect this change with
      added details for better clarity.  The configuration is explicitly
      default-y, to enable the feature on CPUs that have this feature.
      
      It has no effect on non-TBM3 CPUs.
      Signed-off-by: NTim Chen <tim.c.chen@linux.intel.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: bp@suse.de
      Cc: jolsa@redhat.com
      Cc: linux-acpi@vger.kernel.org
      Cc: linux-pm@vger.kernel.org
      Cc: rjw@rjwysocki.net
      Link: http://lkml.kernel.org/r/2b2ee29d93e3f162922d72d0165a1405864fbb23.1480444902.git.tim.c.chen@linux.intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      de966cf4
  3. 25 11月, 2016 1 次提交
    • T
      x86: Enable Intel Turbo Boost Max Technology 3.0 · 5e76b2ab
      Tim Chen 提交于
      On platforms supporting Intel Turbo Boost Max Technology 3.0, the maximum
      turbo frequencies of some cores in a CPU package may be higher than for
      the other cores in the same package.  In that case, better performance
      (and possibly lower energy consumption as well) can be achieved by
      making the scheduler prefer to run tasks on the CPUs with higher max
      turbo frequencies.
      
      To that end, set up a core priority metric to abstract the core
      preferences based on the maximum turbo frequency.  In that metric,
      the cores with higher maximum turbo frequencies are higher-priority
      than the other cores in the same package and that causes the scheduler
      to favor them when making load-balancing decisions using the asymmertic
      packing approach.  At the same time, the priority of SMT threads with a
      higher CPU number is reduced so as to avoid scheduling tasks on all of
      the threads that belong to a favored core before all of the other cores
      have been given a task to run.
      
      The priority metric will be initialized by the P-state driver with the
      help of the sched_set_itmt_core_prio() function.  The P-state driver
      will also determine whether or not ITMT is supported by the platform
      and will call sched_set_itmt_support() to indicate that.
      Co-developed-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
      Co-developed-by: NSrinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
      Signed-off-by: NTim Chen <tim.c.chen@linux.intel.com>
      Cc: linux-pm@vger.kernel.org
      Cc: peterz@infradead.org
      Cc: jolsa@redhat.com
      Cc: rjw@rjwysocki.net
      Cc: linux-acpi@vger.kernel.org
      Cc: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
      Cc: bp@suse.de
      Link: http://lkml.kernel.org/r/cd401ccdff88f88c8349314febdc25d51f7c48f7.1479844244.git.tim.c.chen@linux.intel.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>
      5e76b2ab
  4. 22 11月, 2016 1 次提交
    • Y
      x86/mce/AMD: Add system physical address translation for AMD Fam17h · f5382de9
      Yazen Ghannam 提交于
      The Unified Memory Controllers (UMCs) on Fam17h log a normalized address
      in their MCA_ADDR registers. We need to convert that normalized address
      to a system physical address in order to support a few facilities:
      
      1) To offline poisoned pages in DRAM proactively in the deferred error
         handler.
      
      2) To print sysaddr and page info for DRAM ECC errors in EDAC.
      
      [ Boris: fixes/cleanups ontop:
      
        * hi_addr_offset = 0 - no need for that branch. Stick it all under the
          HiAddrOffsetEn case. It confines hi_addr_offset's declaration too.
      
        * Move variables to the innermost scope they're used at so that we save
          on stack and not blow it up immediately on function entry.
      
        * Do not modify *sys_addr prematurely - we want to not exit early and
          have modified *sys_addr some, which callers get to see. We either
          convert to a sys_addr or we don't do anything. And we signal that with
          the retval of the function.
      
        * Rename label out -> out_err - because it is the error path.
      
        * No need to pr_err of the conversion failed case: imagine a
          sparsely-populated machine with UMCs which don't have DIMMs. Callers
          should look at the retval instead and issue a printk only when really
          necessary. No need for useless info in dmesg.
      
        * s/temp_reg/tmp/ and other variable names shortening => shorter code.
      
        * Use BIT() everywhere.
      
        * Make error messages more informative.
      
        *  Small build fix for the !CONFIG_X86_MCE_AMD case.
      
        * ... and more minor cleanups.
      ]
      Signed-off-by: NYazen Ghannam <Yazen.Ghannam@amd.com>
      Signed-off-by: NBorislav Petkov <bp@suse.de>
      Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
      Cc: Aravind Gopalakrishnan <aravindksg.lkml@gmail.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Tony Luck <tony.luck@intel.com>
      Cc: linux-edac <linux-edac@vger.kernel.org>
      Link: http://lkml.kernel.org/r/20161122111133.mjzpvzhf7o7yl2oa@pd.tnic
      [ Typo fixes. ]
      Signed-off-by: NIngo Molnar <mingo@kernel.org>
      f5382de9
  5. 16 11月, 2016 1 次提交
  6. 15 11月, 2016 6 次提交
  7. 27 10月, 2016 1 次提交
    • F
      x86/intel_rdt: Add CONFIG, Makefile, and basic initialization · 78e99b4a
      Fenghua Yu 提交于
      Introduce CONFIG_INTEL_RDT_A (default: no, dependent on CPU_SUP_INTEL) to
      control inclusion of Resource Director Technology in the build.
      
      Simple init() routine just checks which features are present. If they are
      pr_info() one line summary for each feature for now.
      Signed-off-by: NFenghua Yu <fenghua.yu@intel.com>
      Cc: "Ravi V Shankar" <ravi.v.shankar@intel.com>
      Cc: "Tony Luck" <tony.luck@intel.com>
      Cc: "David Carrillo-Cisneros" <davidcc@google.com>
      Cc: "Sai Prakhya" <sai.praneeth.prakhya@intel.com>
      Cc: "Peter Zijlstra" <peterz@infradead.org>
      Cc: "Stephane Eranian" <eranian@google.com>
      Cc: "Dave Hansen" <dave.hansen@intel.com>
      Cc: "Shaohua Li" <shli@fb.com>
      Cc: "Nilay Vaish" <nilayvaish@gmail.com>
      Cc: "Vikas Shivappa" <vikas.shivappa@linux.intel.com>
      Cc: "Ingo Molnar" <mingo@elte.hu>
      Cc: "Borislav Petkov" <bp@suse.de>
      Cc: "H. Peter Anvin" <h.peter.anvin@intel.com>
      Link: http://lkml.kernel.org/r/1477142405-32078-7-git-send-email-fenghua.yu@intel.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>
      78e99b4a
  8. 24 10月, 2016 1 次提交
  9. 08 10月, 2016 2 次提交
    • V
      atomic64: no need for CONFIG_ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE · 51a02124
      Vineet Gupta 提交于
      This came to light when implementing native 64-bit atomics for ARCv2.
      
      The atomic64 self-test code uses CONFIG_ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
      to check whether atomic64_dec_if_positive() is available.  It seems it
      was needed when not every arch defined it.  However as of current code
      the Kconfig option seems needless
      
       - for CONFIG_GENERIC_ATOMIC64 it is auto-enabled in lib/Kconfig and a
         generic definition of API is present lib/atomic64.c
       - arches with native 64-bit atomics select it in arch/*/Kconfig and
         define the API in their headers
      
      So I see no point in keeping the Kconfig option
      
      Compile tested for:
       - blackfin (CONFIG_GENERIC_ATOMIC64)
       - x86 (!CONFIG_GENERIC_ATOMIC64)
       - ia64
      
      Link: http://lkml.kernel.org/r/1473703083-8625-3-git-send-email-vgupta@synopsys.comSigned-off-by: NVineet Gupta <vgupta@synopsys.com>
      Cc: Richard Henderson <rth@twiddle.net>
      Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
      Cc: Matt Turner <mattst88@gmail.com>
      Cc: Russell King <linux@armlinux.org.uk>
      Cc: Catalin Marinas <catalin.marinas@arm.com>
      Cc: Will Deacon <will.deacon@arm.com>
      Cc: Ralf Baechle <ralf@linux-mips.org>
      Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
      Cc: Helge Deller <deller@gmx.de>
      Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Michael Ellerman <mpe@ellerman.id.au>
      Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
      Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
      Cc: "David S. Miller" <davem@davemloft.net>
      Cc: Chris Metcalf <cmetcalf@mellanox.com>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: "H. Peter Anvin" <hpa@zytor.com>
      Cc: Vineet Gupta <vgupta@synopsys.com>
      Cc: Zhaoxiu Zeng <zhaoxiu.zeng@gmail.com>
      Cc: Linus Walleij <linus.walleij@linaro.org>
      Cc: Alexander Potapenko <glider@google.com>
      Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
      Cc: Herbert Xu <herbert@gondor.apana.org.au>
      Cc: Ming Lin <ming.l@ssi.samsung.com>
      Cc: Arnd Bergmann <arnd@arndb.de>
      Cc: Geert Uytterhoeven <geert@linux-m68k.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Borislav Petkov <bp@suse.de>
      Cc: Andi Kleen <ak@linux.intel.com>
      Cc: Boqun Feng <boqun.feng@gmail.com>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      51a02124
    • Y
      mm/hugetlb: introduce ARCH_HAS_GIGANTIC_PAGE · 461a7184
      Yisheng Xie 提交于
      Avoid making ifdef get pretty unwieldy if many ARCHs support gigantic
      page.  No functional change with this patch.
      
      Link: http://lkml.kernel.org/r/1475227569-63446-2-git-send-email-xieyisheng1@huawei.comSigned-off-by: NYisheng Xie <xieyisheng1@huawei.com>
      Suggested-by: NMichal Hocko <mhocko@suse.com>
      Acked-by: NMichal Hocko <mhocko@suse.com>
      Acked-by: NNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
      Acked-by: NHillf Danton <hillf.zj@alibaba-inc.com>
      Cc: Hanjun Guo <guohanjun@huawei.com>
      Cc: Will Deacon <will.deacon@arm.com>
      Cc: Dave Hansen <dave.hansen@intel.com>
      Cc: Sudeep Holla <sudeep.holla@arm.com>
      Cc: Catalin Marinas <catalin.marinas@arm.com>
      Cc: Mark Rutland <mark.rutland@arm.com>
      Cc: Rob Herring <robh+dt@kernel.org>
      Cc: Mike Kravetz <mike.kravetz@oracle.com>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      461a7184
  10. 05 10月, 2016 1 次提交
  11. 30 9月, 2016 1 次提交
  12. 23 9月, 2016 1 次提交
  13. 15 9月, 2016 1 次提交
  14. 31 8月, 2016 1 次提交
    • J
      mm/usercopy: get rid of CONFIG_DEBUG_STRICT_USER_COPY_CHECKS · 0d025d27
      Josh Poimboeuf 提交于
      There are three usercopy warnings which are currently being silenced for
      gcc 4.6 and newer:
      
      1) "copy_from_user() buffer size is too small" compile warning/error
      
         This is a static warning which happens when object size and copy size
         are both const, and copy size > object size.  I didn't see any false
         positives for this one.  So the function warning attribute seems to
         be working fine here.
      
         Note this scenario is always a bug and so I think it should be
         changed to *always* be an error, regardless of
         CONFIG_DEBUG_STRICT_USER_COPY_CHECKS.
      
      2) "copy_from_user() buffer size is not provably correct" compile warning
      
         This is another static warning which happens when I enable
         __compiletime_object_size() for new compilers (and
         CONFIG_DEBUG_STRICT_USER_COPY_CHECKS).  It happens when object size
         is const, but copy size is *not*.  In this case there's no way to
         compare the two at build time, so it gives the warning.  (Note the
         warning is a byproduct of the fact that gcc has no way of knowing
         whether the overflow function will be called, so the call isn't dead
         code and the warning attribute is activated.)
      
         So this warning seems to only indicate "this is an unusual pattern,
         maybe you should check it out" rather than "this is a bug".
      
         I get 102(!) of these warnings with allyesconfig and the
         __compiletime_object_size() gcc check removed.  I don't know if there
         are any real bugs hiding in there, but from looking at a small
         sample, I didn't see any.  According to Kees, it does sometimes find
         real bugs.  But the false positive rate seems high.
      
      3) "Buffer overflow detected" runtime warning
      
         This is a runtime warning where object size is const, and copy size >
         object size.
      
      All three warnings (both static and runtime) were completely disabled
      for gcc 4.6 with the following commit:
      
        2fb0815c ("gcc4: disable __compiletime_object_size for GCC 4.6+")
      
      That commit mistakenly assumed that the false positives were caused by a
      gcc bug in __compiletime_object_size().  But in fact,
      __compiletime_object_size() seems to be working fine.  The false
      positives were instead triggered by #2 above.  (Though I don't have an
      explanation for why the warnings supposedly only started showing up in
      gcc 4.6.)
      
      So remove warning #2 to get rid of all the false positives, and re-enable
      warnings #1 and #3 by reverting the above commit.
      
      Furthermore, since #1 is a real bug which is detected at compile time,
      upgrade it to always be an error.
      
      Having done all that, CONFIG_DEBUG_STRICT_USER_COPY_CHECKS is no longer
      needed.
      Signed-off-by: NJosh Poimboeuf <jpoimboe@redhat.com>
      Cc: Kees Cook <keescook@chromium.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Ingo Molnar <mingo@kernel.org>
      Cc: "H . Peter Anvin" <hpa@zytor.com>
      Cc: Andy Lutomirski <luto@amacapital.net>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: Brian Gerst <brgerst@gmail.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Frederic Weisbecker <fweisbec@gmail.com>
      Cc: Byungchul Park <byungchul.park@lge.com>
      Cc: Nilay Vaish <nilayvaish@gmail.com>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      0d025d27
  15. 24 8月, 2016 2 次提交
    • J
      ftrace: Remove CONFIG_HAVE_FUNCTION_GRAPH_FP_TEST from config · e4a744ef
      Josh Poimboeuf 提交于
      Make HAVE_FUNCTION_GRAPH_FP_TEST a normal define, independent from
      kconfig.  This removes some config file pollution and simplifies the
      checking for the fp test.
      Suggested-by: NSteven Rostedt <rostedt@goodmis.org>
      Signed-off-by: NJosh Poimboeuf <jpoimboe@redhat.com>
      Acked-by: NSteven Rostedt <rostedt@goodmis.org>
      Cc: Andy Lutomirski <luto@amacapital.net>
      Cc: Andy Lutomirski <luto@kernel.org>
      Cc: Borislav Petkov <bp@alien8.de>
      Cc: Brian Gerst <brgerst@gmail.com>
      Cc: Byungchul Park <byungchul.park@lge.com>
      Cc: Denys Vlasenko <dvlasenk@redhat.com>
      Cc: Frederic Weisbecker <fweisbec@gmail.com>
      Cc: H. Peter Anvin <hpa@zytor.com>
      Cc: Kees Cook <keescook@chromium.org>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Nilay Vaish <nilayvaish@gmail.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Link: http://lkml.kernel.org/r/2c4e5f05054d6d367f702fd153af7a0109dd5c81.1471607358.git.jpoimboe@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      e4a744ef
    • A
      x86/mm/64: Enable vmapped stacks (CONFIG_HAVE_ARCH_VMAP_STACK=y) · e37e43a4
      Andy Lutomirski 提交于
      This allows x86_64 kernels to enable vmapped stacks by setting
      HAVE_ARCH_VMAP_STACK=y - which enables the CONFIG_VMAP_STACK=y
      high level Kconfig option.
      
      There are a couple of interesting bits:
      
      First, x86 lazily faults in top-level paging entries for the vmalloc
      area.  This won't work if we get a page fault while trying to access
      the stack: the CPU will promote it to a double-fault and we'll die.
      To avoid this problem, probe the new stack when switching stacks and
      forcibly populate the pgd entry for the stack when switching mms.
      
      Second, once we have guard pages around the stack, we'll want to
      detect and handle stack overflow.
      
      I didn't enable it on x86_32.  We'd need to rework the double-fault
      code a bit and I'm concerned about running out of vmalloc virtual
      addresses under some workloads.
      
      This patch, by itself, will behave somewhat erratically when the
      stack overflows while RSP is still more than a few tens of bytes
      above the bottom of the stack.  Specifically, we'll get #PF and make
      it to no_context and them oops without reliably triggering a
      double-fault, and no_context doesn't know about stack overflows.
      The next patch will improve that case.
      
      Thank you to Nadav and Brian for helping me pay enough attention to
      the SDM to hopefully get this right.
      Signed-off-by: NAndy Lutomirski <luto@kernel.org>
      Cc: Borislav Petkov <bp@alien8.de>
      Cc: Brian Gerst <brgerst@gmail.com>
      Cc: Denys Vlasenko <dvlasenk@redhat.com>
      Cc: H. Peter Anvin <hpa@zytor.com>
      Cc: Josh Poimboeuf <jpoimboe@redhat.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Nadav Amit <nadav.amit@gmail.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Link: http://lkml.kernel.org/r/c88f3e2920b18e6cc621d772a04a62c06869037e.1470907718.git.luto@kernel.org
      [ Minor edits. ]
      Signed-off-by: NIngo Molnar <mingo@kernel.org>
      e37e43a4
  16. 27 7月, 2016 2 次提交
  17. 08 7月, 2016 2 次提交
    • T
      x86/mm: Add memory hotplug support for KASLR memory randomization · 90397a41
      Thomas Garnier 提交于
      Add a new option (CONFIG_RANDOMIZE_MEMORY_PHYSICAL_PADDING) to define
      the padding used for the physical memory mapping section when KASLR
      memory is enabled. It ensures there is enough virtual address space when
      CONFIG_MEMORY_HOTPLUG is used. The default value is 10 terabytes. If
      CONFIG_MEMORY_HOTPLUG is not used, no space is reserved increasing the
      entropy available.
      Signed-off-by: NThomas Garnier <thgarnie@google.com>
      Signed-off-by: NKees Cook <keescook@chromium.org>
      Cc: Alexander Kuleshov <kuleshovmail@gmail.com>
      Cc: Alexander Popov <alpopov@ptsecurity.com>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Andy Lutomirski <luto@kernel.org>
      Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
      Cc: Baoquan He <bhe@redhat.com>
      Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
      Cc: Borislav Petkov <bp@alien8.de>
      Cc: Borislav Petkov <bp@suse.de>
      Cc: Brian Gerst <brgerst@gmail.com>
      Cc: Christian Borntraeger <borntraeger@de.ibm.com>
      Cc: Dan Williams <dan.j.williams@intel.com>
      Cc: Dave Hansen <dave.hansen@linux.intel.com>
      Cc: Dave Young <dyoung@redhat.com>
      Cc: Denys Vlasenko <dvlasenk@redhat.com>
      Cc: Dmitry Vyukov <dvyukov@google.com>
      Cc: H. Peter Anvin <hpa@zytor.com>
      Cc: Jan Beulich <JBeulich@suse.com>
      Cc: Joerg Roedel <jroedel@suse.de>
      Cc: Jonathan Corbet <corbet@lwn.net>
      Cc: Josh Poimboeuf <jpoimboe@redhat.com>
      Cc: Juergen Gross <jgross@suse.com>
      Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Lv Zheng <lv.zheng@intel.com>
      Cc: Mark Salter <msalter@redhat.com>
      Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
      Cc: Matt Fleming <matt@codeblueprint.co.uk>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Stephen Smalley <sds@tycho.nsa.gov>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Toshi Kani <toshi.kani@hpe.com>
      Cc: Xiao Guangrong <guangrong.xiao@linux.intel.com>
      Cc: Yinghai Lu <yinghai@kernel.org>
      Cc: kernel-hardening@lists.openwall.com
      Cc: linux-doc@vger.kernel.org
      Link: http://lkml.kernel.org/r/1466556426-32664-10-git-send-email-keescook@chromium.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
      90397a41
    • T
      x86/mm: Implement ASLR for kernel memory regions · 0483e1fa
      Thomas Garnier 提交于
      Randomizes the virtual address space of kernel memory regions for
      x86_64. This first patch adds the infrastructure and does not randomize
      any region. The following patches will randomize the physical memory
      mapping, vmalloc and vmemmap regions.
      
      This security feature mitigates exploits relying on predictable kernel
      addresses. These addresses can be used to disclose the kernel modules
      base addresses or corrupt specific structures to elevate privileges
      bypassing the current implementation of KASLR. This feature can be
      enabled with the CONFIG_RANDOMIZE_MEMORY option.
      
      The order of each memory region is not changed. The feature looks at the
      available space for the regions based on different configuration options
      and randomizes the base and space between each. The size of the physical
      memory mapping is the available physical memory. No performance impact
      was detected while testing the feature.
      
      Entropy is generated using the KASLR early boot functions now shared in
      the lib directory (originally written by Kees Cook). Randomization is
      done on PGD & PUD page table levels to increase possible addresses. The
      physical memory mapping code was adapted to support PUD level virtual
      addresses. This implementation on the best configuration provides 30,000
      possible virtual addresses in average for each memory region.  An
      additional low memory page is used to ensure each CPU can start with a
      PGD aligned virtual address (for realmode).
      
      x86/dump_pagetable was updated to correctly display each region.
      
      Updated documentation on x86_64 memory layout accordingly.
      
      Performance data, after all patches in the series:
      
      Kernbench shows almost no difference (-+ less than 1%):
      
      Before:
      
      Average Optimal load -j 12 Run (std deviation): Elapsed Time 102.63 (1.2695)
      User Time 1034.89 (1.18115) System Time 87.056 (0.456416) Percent CPU 1092.9
      (13.892) Context Switches 199805 (3455.33) Sleeps 97907.8 (900.636)
      
      After:
      
      Average Optimal load -j 12 Run (std deviation): Elapsed Time 102.489 (1.10636)
      User Time 1034.86 (1.36053) System Time 87.764 (0.49345) Percent CPU 1095
      (12.7715) Context Switches 199036 (4298.1) Sleeps 97681.6 (1031.11)
      
      Hackbench shows 0% difference on average (hackbench 90 repeated 10 times):
      
      attemp,before,after 1,0.076,0.069 2,0.072,0.069 3,0.066,0.066 4,0.066,0.068
      5,0.066,0.067 6,0.066,0.069 7,0.067,0.066 8,0.063,0.067 9,0.067,0.065
      10,0.068,0.071 average,0.0677,0.0677
      Signed-off-by: NThomas Garnier <thgarnie@google.com>
      Signed-off-by: NKees Cook <keescook@chromium.org>
      Cc: Alexander Kuleshov <kuleshovmail@gmail.com>
      Cc: Alexander Popov <alpopov@ptsecurity.com>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Andy Lutomirski <luto@kernel.org>
      Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
      Cc: Baoquan He <bhe@redhat.com>
      Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
      Cc: Borislav Petkov <bp@alien8.de>
      Cc: Borislav Petkov <bp@suse.de>
      Cc: Brian Gerst <brgerst@gmail.com>
      Cc: Christian Borntraeger <borntraeger@de.ibm.com>
      Cc: Dan Williams <dan.j.williams@intel.com>
      Cc: Dave Hansen <dave.hansen@linux.intel.com>
      Cc: Dave Young <dyoung@redhat.com>
      Cc: Denys Vlasenko <dvlasenk@redhat.com>
      Cc: Dmitry Vyukov <dvyukov@google.com>
      Cc: H. Peter Anvin <hpa@zytor.com>
      Cc: Jan Beulich <JBeulich@suse.com>
      Cc: Joerg Roedel <jroedel@suse.de>
      Cc: Jonathan Corbet <corbet@lwn.net>
      Cc: Josh Poimboeuf <jpoimboe@redhat.com>
      Cc: Juergen Gross <jgross@suse.com>
      Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Lv Zheng <lv.zheng@intel.com>
      Cc: Mark Salter <msalter@redhat.com>
      Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
      Cc: Matt Fleming <matt@codeblueprint.co.uk>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Stephen Smalley <sds@tycho.nsa.gov>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Toshi Kani <toshi.kani@hpe.com>
      Cc: Xiao Guangrong <guangrong.xiao@linux.intel.com>
      Cc: Yinghai Lu <yinghai@kernel.org>
      Cc: kernel-hardening@lists.openwall.com
      Cc: linux-doc@vger.kernel.org
      Link: http://lkml.kernel.org/r/1466556426-32664-6-git-send-email-keescook@chromium.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
      0483e1fa
  18. 26 6月, 2016 2 次提交
    • K
      x86/KASLR: Extend kernel image physical address randomization to addresses larger than 4G · ed9f007e
      Kees Cook 提交于
      We want the physical address to be randomized anywhere between
      16MB and the top of physical memory (up to 64TB).
      
      This patch exchanges the prior slots[] array for the new slot_areas[]
      array, and lifts the limitation of KERNEL_IMAGE_SIZE on the physical
      address offset for 64-bit. As before, process_e820_entry() walks
      memory and populates slot_areas[], splitting on any detected mem_avoid
      collisions.
      
      Finally, since the slots[] array and its associated functions are not
      needed any more, so they are removed.
      
      Based on earlier patches by Baoquan He.
      
      Originally-from: Baoquan He <bhe@redhat.com>
      Signed-off-by: NKees Cook <keescook@chromium.org>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
      Cc: Andy Lutomirski <luto@kernel.org>
      Cc: Baoquan He <bhe@redhat.com>
      Cc: Borislav Petkov <bp@alien8.de>
      Cc: Brian Gerst <brgerst@gmail.com>
      Cc: Denys Vlasenko <dvlasenk@redhat.com>
      Cc: Dmitry Vyukov <dvyukov@google.com>
      Cc: H. Peter Anvin <hpa@zytor.com>
      Cc: H.J. Lu <hjl.tools@gmail.com>
      Cc: Josh Poimboeuf <jpoimboe@redhat.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Yinghai Lu <yinghai@kernel.org>
      Link: http://lkml.kernel.org/r/1464216334-17200-5-git-send-email-keescook@chromium.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
      ed9f007e
    • A
      rtc: move mc146818 helper functions out-of-line · d6faca40
      Arnd Bergmann 提交于
      The mc146818_get_time/mc146818_set_time functions are rather large
      inline functions in a global header file and are used in several
      drivers and in x86 specific code.
      
      Here we move them into a separate .c file that is compiled whenever
      any of the users require it. This also lets us remove the linux/acpi.h
      header inclusion from mc146818rtc.h, which in turn avoids some
      warnings about duplicate definition of the TRUE/FALSE macros.
      Signed-off-by: NArnd Bergmann <arnd@arndb.de>
      Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>
      d6faca40
  19. 22 6月, 2016 1 次提交
  20. 18 6月, 2016 1 次提交
    • W
      isa: Allow ISA-style drivers on modern systems · 3a495511
      William Breathitt Gray 提交于
      Several modern devices, such as PC/104 cards, are expected to run on
      modern systems via an ISA bus interface. Since ISA is a legacy interface
      for most modern architectures, ISA support should remain disabled in
      general. Support for ISA-style drivers should be enabled on a per driver
      basis.
      
      To allow ISA-style drivers on modern systems, this patch introduces the
      ISA_BUS_API and ISA_BUS Kconfig options. The ISA bus driver will now
      build conditionally on the ISA_BUS_API Kconfig option, which defaults to
      the legacy ISA Kconfig option. The ISA_BUS Kconfig option allows the
      ISA_BUS_API Kconfig option to be selected on architectures which do not
      enable ISA (e.g. X86_64).
      
      The ISA_BUS Kconfig option is currently only implemented for X86
      architectures. Other architectures may have their own ISA_BUS Kconfig
      options added as required.
      Reviewed-by: NGuenter Roeck <linux@roeck-us.net>
      Signed-off-by: NWilliam Breathitt Gray <vilhelm.gray@gmail.com>
      Acked-by: NLinus Torvalds <torvalds@linux-foundation.org>
      Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      3a495511
  21. 10 6月, 2016 1 次提交
  22. 08 6月, 2016 2 次提交
    • B
      x86/hweight: Get rid of the special calling convention · f5967101
      Borislav Petkov 提交于
      People complained about ARCH_HWEIGHT_CFLAGS and how it throws a wrench
      into kcov, lto, etc, experimentations.
      
      Add asm versions for __sw_hweight{32,64}() and do explicit saving and
      restoring of clobbered registers. This gets rid of the special calling
      convention. We get to call those functions on !X86_FEATURE_POPCNT CPUs.
      
      We still need to hardcode POPCNT and register operands as some old gas
      versions which we support, do not know about POPCNT.
      
      Btw, remove redundant REX prefix from 32-bit POPCNT because alternatives
      can do padding now.
      Suggested-by: NH. Peter Anvin <hpa@zytor.com>
      Signed-off-by: NBorislav Petkov <bp@suse.de>
      Acked-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
      Cc: Andy Lutomirski <luto@amacapital.net>
      Cc: Borislav Petkov <bp@alien8.de>
      Cc: Brian Gerst <brgerst@gmail.com>
      Cc: Denys Vlasenko <dvlasenk@redhat.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Link: http://lkml.kernel.org/r/1464605787-20603-1-git-send-email-bp@alien8.deSigned-off-by: NIngo Molnar <mingo@kernel.org>
      f5967101
    • E
      GCC plugin infrastructure · 6b90bd4b
      Emese Revfy 提交于
      This patch allows to build the whole kernel with GCC plugins. It was ported from
      grsecurity/PaX. The infrastructure supports building out-of-tree modules and
      building in a separate directory. Cross-compilation is supported too.
      Currently the x86, arm, arm64 and uml architectures enable plugins.
      
      The directory of the gcc plugins is scripts/gcc-plugins. You can use a file or a directory
      there. The plugins compile with these options:
       * -fno-rtti: gcc is compiled with this option so the plugins must use it too
       * -fno-exceptions: this is inherited from gcc too
       * -fasynchronous-unwind-tables: this is inherited from gcc too
       * -ggdb: it is useful for debugging a plugin (better backtrace on internal
          errors)
       * -Wno-narrowing: to suppress warnings from gcc headers (ipa-utils.h)
       * -Wno-unused-variable: to suppress warnings from gcc headers (gcc_version
          variable, plugin-version.h)
      
      The infrastructure introduces a new Makefile target called gcc-plugins. It
      supports all gcc versions from 4.5 to 6.0. The scripts/gcc-plugin.sh script
      chooses the proper host compiler (gcc-4.7 can be built by either gcc or g++).
      This script also checks the availability of the included headers in
      scripts/gcc-plugins/gcc-common.h.
      
      The gcc-common.h header contains frequently included headers for GCC plugins
      and it has a compatibility layer for the supported gcc versions.
      
      The gcc-generate-*-pass.h headers automatically generate the registration
      structures for GIMPLE, SIMPLE_IPA, IPA and RTL passes.
      
      Note that 'make clean' keeps the *.so files (only the distclean or mrproper
      targets clean all) because they are needed for out-of-tree modules.
      
      Based on work created by the PaX Team.
      Signed-off-by: NEmese Revfy <re.emese@gmail.com>
      Acked-by: NKees Cook <keescook@chromium.org>
      Signed-off-by: NMichal Marek <mmarek@suse.com>
      6b90bd4b
  23. 22 5月, 2016 1 次提交
    • L
      x86 isa: add back X86_32 dependency on CONFIG_ISA · 51e68d05
      Linus Torvalds 提交于
      Commit b3c1be1b ("base: isa: Remove X86_32 dependency") made ISA
      support available on x86-64 too.  That's not right - while there are
      some LPC-style devices that might be useful still and be based on
      ISA-like IP blocks, that is *not* an excuse to try to enable any random
      legacy drivers.
      
      Such drivers should be individually enabled and made to perhaps depend
      on ISA_DMA_API instead (which we have continued to support on x86-64).
      Or we could add another "ISA_XYZ_API" that we support that doesn't
      enable random old drivers that aren't even 64-bit clean nor do we have
      any test coverage for.
      
      Turning off ISA will now also turn off some drivers that have been
      marked as depending on it as part of this series, and that used to work
      on modern platforms.
      
      See for example commits ad7afc38..cc736607, which may also need
      to be reverted.
      
      This commit means that the warnings that came in due to enabling ISA
      widely are now gone again.
      Acked-by: NWilliam Breathitt Gray <vilhelm.gray@gmail.com>
      Cc: Linus Walleij <linus.walleij@linaro.org>
      Cc: Guenter Roeck <linux@roeck-us.net>
      Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      51e68d05
  24. 21 5月, 2016 2 次提交
    • P
      printk/nmi: generic solution for safe printk in NMI · 42a0bb3f
      Petr Mladek 提交于
      printk() takes some locks and could not be used a safe way in NMI
      context.
      
      The chance of a deadlock is real especially when printing stacks from
      all CPUs.  This particular problem has been addressed on x86 by the
      commit a9edc880 ("x86/nmi: Perform a safe NMI stack trace on all
      CPUs").
      
      The patchset brings two big advantages.  First, it makes the NMI
      backtraces safe on all architectures for free.  Second, it makes all NMI
      messages almost safe on all architectures (the temporary buffer is
      limited.  We still should keep the number of messages in NMI context at
      minimum).
      
      Note that there already are several messages printed in NMI context:
      WARN_ON(in_nmi()), BUG_ON(in_nmi()), anything being printed out from MCE
      handlers.  These are not easy to avoid.
      
      This patch reuses most of the code and makes it generic.  It is useful
      for all messages and architectures that support NMI.
      
      The alternative printk_func is set when entering and is reseted when
      leaving NMI context.  It queues IRQ work to copy the messages into the
      main ring buffer in a safe context.
      
      __printk_nmi_flush() copies all available messages and reset the buffer.
      Then we could use a simple cmpxchg operations to get synchronized with
      writers.  There is also used a spinlock to get synchronized with other
      flushers.
      
      We do not longer use seq_buf because it depends on external lock.  It
      would be hard to make all supported operations safe for a lockless use.
      It would be confusing and error prone to make only some operations safe.
      
      The code is put into separate printk/nmi.c as suggested by Steven
      Rostedt.  It needs a per-CPU buffer and is compiled only on
      architectures that call nmi_enter().  This is achieved by the new
      HAVE_NMI Kconfig flag.
      
      The are MN10300 and Xtensa architectures.  We need to clean up NMI
      handling there first.  Let's do it separately.
      
      The patch is heavily based on the draft from Peter Zijlstra, see
      
        https://lkml.org/lkml/2015/6/10/327
      
      [arnd@arndb.de: printk-nmi: use %zu format string for size_t]
      [akpm@linux-foundation.org: min_t->min - all types are size_t here]
      Signed-off-by: NPetr Mladek <pmladek@suse.com>
      Suggested-by: NPeter Zijlstra <peterz@infradead.org>
      Suggested-by: NSteven Rostedt <rostedt@goodmis.org>
      Cc: Jan Kara <jack@suse.cz>
      Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>	[arm part]
      Cc: Daniel Thompson <daniel.thompson@linaro.org>
      Cc: Jiri Kosina <jkosina@suse.com>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Ralf Baechle <ralf@linux-mips.org>
      Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
      Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
      Cc: David Miller <davem@davemloft.net>
      Cc: Daniel Thompson <daniel.thompson@linaro.org>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      42a0bb3f
    • J
      exit_thread: remove empty bodies · 5f56a5df
      Jiri Slaby 提交于
      Define HAVE_EXIT_THREAD for archs which want to do something in
      exit_thread. For others, let's define exit_thread as an empty inline.
      
      This is a cleanup before we change the prototype of exit_thread to
      accept a task parameter.
      
      [akpm@linux-foundation.org: fix mips]
      Signed-off-by: NJiri Slaby <jslaby@suse.cz>
      Cc: "David S. Miller" <davem@davemloft.net>
      Cc: "H. Peter Anvin" <hpa@zytor.com>
      Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
      Cc: Aurelien Jacquiot <a-jacquiot@ti.com>
      Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
      Cc: Catalin Marinas <catalin.marinas@arm.com>
      Cc: Chen Liqin <liqin.linux@gmail.com>
      Cc: Chris Metcalf <cmetcalf@mellanox.com>
      Cc: Chris Zankel <chris@zankel.net>
      Cc: David Howells <dhowells@redhat.com>
      Cc: Fenghua Yu <fenghua.yu@intel.com>
      Cc: Geert Uytterhoeven <geert@linux-m68k.org>
      Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
      Cc: Haavard Skinnemoen <hskinnemoen@gmail.com>
      Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no>
      Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
      Cc: Helge Deller <deller@gmx.de>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
      Cc: James Hogan <james.hogan@imgtec.com>
      Cc: Jeff Dike <jdike@addtoit.com>
      Cc: Jesper Nilsson <jesper.nilsson@axis.com>
      Cc: Jiri Slaby <jslaby@suse.cz>
      Cc: Jonas Bonn <jonas@southpole.se>
      Cc: Koichi Yasutake <yasutake.koichi@jp.panasonic.com>
      Cc: Lennox Wu <lennox.wu@gmail.com>
      Cc: Ley Foon Tan <lftan@altera.com>
      Cc: Mark Salter <msalter@redhat.com>
      Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
      Cc: Matt Turner <mattst88@gmail.com>
      Cc: Max Filippov <jcmvbkbc@gmail.com>
      Cc: Michael Ellerman <mpe@ellerman.id.au>
      Cc: Michal Simek <monstr@monstr.eu>
      Cc: Mikael Starvik <starvik@axis.com>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Ralf Baechle <ralf@linux-mips.org>
      Cc: Rich Felker <dalias@libc.org>
      Cc: Richard Henderson <rth@twiddle.net>
      Cc: Richard Kuo <rkuo@codeaurora.org>
      Cc: Richard Weinberger <richard@nod.at>
      Cc: Russell King <linux@arm.linux.org.uk>
      Cc: Steven Miao <realmz6@gmail.com>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Tony Luck <tony.luck@intel.com>
      Cc: Vineet Gupta <vgupta@synopsys.com>
      Cc: Will Deacon <will.deacon@arm.com>
      Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      5f56a5df
  25. 17 5月, 2016 1 次提交
    • D
      bpf: split HAVE_BPF_JIT into cBPF and eBPF variant · 6077776b
      Daniel Borkmann 提交于
      Split the HAVE_BPF_JIT into two for distinguishing cBPF and eBPF JITs.
      
      Current cBPF ones:
      
        # git grep -n HAVE_CBPF_JIT arch/
        arch/arm/Kconfig:44:    select HAVE_CBPF_JIT
        arch/mips/Kconfig:18:   select HAVE_CBPF_JIT if !CPU_MICROMIPS
        arch/powerpc/Kconfig:129:       select HAVE_CBPF_JIT
        arch/sparc/Kconfig:35:  select HAVE_CBPF_JIT
      
      Current eBPF ones:
      
        # git grep -n HAVE_EBPF_JIT arch/
        arch/arm64/Kconfig:61:  select HAVE_EBPF_JIT
        arch/s390/Kconfig:126:  select HAVE_EBPF_JIT if PACK_STACK && HAVE_MARCH_Z196_FEATURES
        arch/x86/Kconfig:94:    select HAVE_EBPF_JIT                    if X86_64
      
      Later code also needs this facility to check for eBPF JITs.
      Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
      Acked-by: NAlexei Starovoitov <ast@kernel.org>
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      6077776b
  26. 02 5月, 2016 1 次提交
  27. 22 4月, 2016 1 次提交
    • B
      x86/KASLR: Drop CONFIG_RANDOMIZE_BASE_MAX_OFFSET · e8581e3d
      Baoquan He 提交于
      Currently CONFIG_RANDOMIZE_BASE_MAX_OFFSET is used to limit the maximum
      offset for kernel randomization. This limit doesn't need to be a CONFIG
      since it is tied completely to KERNEL_IMAGE_SIZE, and will make no sense
      once physical and virtual offsets are randomized separately. This patch
      removes CONFIG_RANDOMIZE_BASE_MAX_OFFSET and consolidates the Kconfig
      help text.
      
      [kees: rewrote changelog, dropped KERNEL_IMAGE_SIZE_DEFAULT, rewrote help]
      Signed-off-by: NBaoquan He <bhe@redhat.com>
      Signed-off-by: NKees Cook <keescook@chromium.org>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
      Cc: Andy Lutomirski <luto@amacapital.net>
      Cc: Andy Lutomirski <luto@kernel.org>
      Cc: Borislav Petkov <bp@alien8.de>
      Cc: Borislav Petkov <bp@suse.de>
      Cc: Brian Gerst <brgerst@gmail.com>
      Cc: Denys Vlasenko <dvlasenk@redhat.com>
      Cc: Dmitry Vyukov <dvyukov@google.com>
      Cc: H. Peter Anvin <hpa@zytor.com>
      Cc: H.J. Lu <hjl.tools@gmail.com>
      Cc: Josh Poimboeuf <jpoimboe@redhat.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Yinghai Lu <yinghai@kernel.org>
      Link: http://lkml.kernel.org/r/1461185746-8017-3-git-send-email-keescook@chromium.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
      e8581e3d