1. 10 12月, 2016 5 次提交
    • T
      x86: Remove empty idle.h header · 34bc3560
      Thomas Gleixner 提交于
      One include less is always a good thing(tm). Good riddance.
      Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
      Signed-off-by: NBorislav Petkov <bp@suse.de>
      Cc: Jiri Olsa <jolsa@redhat.com>
      Link: http://lkml.kernel.org/r/20161209182912.2726-6-bp@alien8.deSigned-off-by: NThomas Gleixner <tglx@linutronix.de>
      34bc3560
    • B
      x86/amd: Simplify AMD E400 aware idle routine · 07c94a38
      Borislav Petkov 提交于
      Reorganize the E400 detection now that we have everything in place:
      switch the CPUs to broadcast mode after the LAPIC has been initialized
      and remove the facilities that were used previously on the idle path.
      
      Unfortunately static_cpu_has_bug() cannpt be used in the E400 idle routine
      because alternatives have been applied when the actual detection happens,
      so the static switching does not take effect and the test will stay
      false. Use boot_cpu_has_bug() instead which is definitely an improvement
      over the RDMSR and the cpumask handling.
      Suggested-by: NThomas Gleixner <tglx@linutronix.de>
      Signed-off-by: NBorislav Petkov <bp@suse.de>
      Cc: Jiri Olsa <jolsa@redhat.com>
      Link: http://lkml.kernel.org/r/20161209182912.2726-5-bp@alien8.deSigned-off-by: NThomas Gleixner <tglx@linutronix.de>
      07c94a38
    • T
      x86/amd: Check for the C1E bug post ACPI subsystem init · e7ff3a47
      Thomas Gleixner 提交于
      AMD CPUs affected by the E400 erratum suffer from the issue that the
      local APIC timer stops when the CPU goes into C1E. Unfortunately there
      is no way to detect the affected CPUs on early boot. It's only possible
      to determine the range of possibly affected CPUs from the family/model
      range.
      
      The actual decision whether to enter C1E and thus cause the bug is done
      by the firmware and we need to detect that case late, after ACPI has
      been initialized.
      
      The current solution is to check in the idle routine whether the CPU is
      affected by reading the MSR_K8_INT_PENDING_MSG MSR and checking for the
      K8_INTP_C1E_ACTIVE_MASK bits. If one of the bits is set then the CPU is
      affected and the system is switched into forced broadcast mode.
      
      This is ineffective and on non-affected CPUs every entry to idle does
      the extra RDMSR.
      
      After doing some research it turns out that the bits are visible on the
      boot CPU right after the ACPI subsystem is initialized in the early
      boot process. So instead of polling for the bits in the idle loop, add
      a detection function after acpi_subsystem_init() and check for the MSR
      bits. If set, then the X86_BUG_AMD_APIC_C1E is set on the boot CPU and
      the TSC is marked unstable when X86_FEATURE_NONSTOP_TSC is not set as it
      will stop in C1E state as well.
      
      The switch to broadcast mode cannot be done at this point because the
      boot CPU still uses HPET as a clockevent device and the local APIC timer
      is not yet calibrated and installed. The switch to broadcast mode on the
      affected CPUs needs to be done when the local APIC timer is actually set
      up.
      
      This allows to cleanup the amd_e400_idle() function in the next step.
      Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
      Signed-off-by: NBorislav Petkov <bp@suse.de>
      Cc: Jiri Olsa <jolsa@redhat.com>
      Link: http://lkml.kernel.org/r/20161209182912.2726-4-bp@alien8.deSigned-off-by: NThomas Gleixner <tglx@linutronix.de>
      e7ff3a47
    • T
      x86/bugs: Separate AMD E400 erratum and C1E bug · 3344ed30
      Thomas Gleixner 提交于
      The workaround for the AMD Erratum E400 (Local APIC timer stops in C1E
      state) is a two step process:
      
       - Selection of the E400 aware idle routine
      
       - Detection whether the platform is affected
      
      The idle routine selection happens for possibly affected CPUs depending on
      family/model/stepping information. These range of CPUs is not necessarily
      affected as the decision whether to enable the C1E feature is made by the
      firmware. Unfortunately there is no way to query this at early boot.
      
      The current implementation polls a MSR in the E400 aware idle routine to
      detect whether the CPU is affected. This is inefficient on non affected
      CPUs because every idle entry has to do the MSR read.
      
      There is a better way to detect this before going idle for the first time
      which requires to seperate the bug flags:
      
        X86_BUG_AMD_E400 	- Selects the E400 aware idle routine and
        			  enables the detection
      			  
        X86_BUG_AMD_APIC_C1E  - Set when the platform is affected by E400
      
      Replace the current X86_BUG_AMD_APIC_C1E usage by the new X86_BUG_AMD_E400
      bug bit to select the idle routine which currently does an unconditional
      detection poll. X86_BUG_AMD_APIC_C1E is going to be used in later patches
      to remove the MSR polling and simplify the handling of this misfeature.
      Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
      Signed-off-by: NBorislav Petkov <bp@suse.de>
      Cc: Jiri Olsa <jolsa@redhat.com>
      Link: http://lkml.kernel.org/r/20161209182912.2726-3-bp@alien8.deSigned-off-by: NThomas Gleixner <tglx@linutronix.de>
      3344ed30
    • B
      x86/cpufeature: Provide helper to set bugs bits · a588b983
      Borislav Petkov 提交于
      Will be used in a later patch to set bug bits for bugs which need late
      detection.
      Signed-off-by: NBorislav Petkov <bp@suse.de>
      Cc: Jiri Olsa <jolsa@redhat.com>
      Link: http://lkml.kernel.org/r/20161209182912.2726-2-bp@alien8.deSigned-off-by: NThomas Gleixner <tglx@linutronix.de>
      a588b983
  2. 18 11月, 2016 4 次提交
  3. 12 11月, 2016 6 次提交
    • A
      crypto: aesni: shut up -Wmaybe-uninitialized warning · beae2c9e
      Arnd Bergmann 提交于
      The rfc4106 encrypy/decrypt helper functions cause an annoying
      false-positive warning in allmodconfig if we turn on
      -Wmaybe-uninitialized warnings again:
      
        arch/x86/crypto/aesni-intel_glue.c: In function ‘helper_rfc4106_decrypt’:
        include/linux/scatterlist.h:67:31: warning: ‘dst_sg_walk.sg’ may be used uninitialized in this function [-Wmaybe-uninitialized]
      
      The problem seems to be that the compiler doesn't track the state of the
      'one_entry_in_sg' variable across the kernel_fpu_begin/kernel_fpu_end
      section.
      
      This takes the easy way out by adding a bogus initialization, which
      should be harmless enough to get the patch into v4.9 so we can turn on
      this warning again by default without producing useless output.  A
      follow-up patch for v4.10 rearranges the code to make the warning go
      away.
      Signed-off-by: NArnd Bergmann <arnd@arndb.de>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      beae2c9e
    • A
      s390: pci: don't print uninitialized data for debugging · 92dfffee
      Arnd Bergmann 提交于
      gcc correctly warns about an incorrect use of the 'pa' variable in case
      we pass an empty scatterlist to __s390_dma_map_sg:
      
        arch/s390/pci/pci_dma.c: In function '__s390_dma_map_sg':
        arch/s390/pci/pci_dma.c:309:13: warning: 'pa' may be used uninitialized in this function [-Wmaybe-uninitialized]
      
      This adds a bogus initialization to the function to sanitize the debug
      output.  I would have preferred a solution without the initialization,
      but I only got the report from the kbuild bot after turning on the
      warning again, and didn't manage to reproduce it myself.
      Signed-off-by: NArnd Bergmann <arnd@arndb.de>
      Acked-by: NSebastian Ott <sebott@linux.vnet.ibm.com>
      Acked-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      92dfffee
    • A
      nios2: fix timer initcall return value · 069013a9
      Arnd Bergmann 提交于
      When called more than twice, the nios2_time_init() function return an
      uninitialized value, as detected by gcc -Wmaybe-uninitialized
      
        arch/nios2/kernel/time.c: warning: 'ret' may be used uninitialized in this function
      
      This makes it return '0' here, matching the comment above the function.
      Acked-by: NLey Foon Tan <lftan@altera.com>
      Signed-off-by: NArnd Bergmann <arnd@arndb.de>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      069013a9
    • A
      x86: apm: avoid uninitialized data · 3a6d8676
      Arnd Bergmann 提交于
      apm_bios_call() can fail, and return a status in its argument structure.
      If that status however is zero during a call from
      apm_get_power_status(), we end up using data that may have never been
      set, as reported by "gcc -Wmaybe-uninitialized":
      
        arch/x86/kernel/apm_32.c: In function ‘apm’:
        arch/x86/kernel/apm_32.c:1729:17: error: ‘bx’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
        arch/x86/kernel/apm_32.c:1835:5: error: ‘cx’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
        arch/x86/kernel/apm_32.c:1730:17: note: ‘cx’ was declared here
        arch/x86/kernel/apm_32.c:1842:27: error: ‘dx’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
        arch/x86/kernel/apm_32.c:1731:17: note: ‘dx’ was declared here
      
      This changes the function to return "APM_NO_ERROR" here, which makes the
      code more robust to broken BIOS versions, and avoids the warning.
      Signed-off-by: NArnd Bergmann <arnd@arndb.de>
      Reviewed-by: NJiri Kosina <jkosina@suse.cz>
      Reviewed-by: NLuis R. Rodriguez <mcgrof@kernel.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      3a6d8676
    • A
      Kbuild: enable -Wmaybe-uninitialized warning for "make W=1" · a76bcf55
      Arnd Bergmann 提交于
      Traditionally, we have always had warnings about uninitialized variables
      enabled, as this is part of -Wall, and generally a good idea [1], but it
      also always produced false positives, mainly because this is a variation
      of the halting problem and provably impossible to get right in all cases
      [2].
      
      Various people have identified cases that are particularly bad for false
      positives, and in commit e74fc973 ("Turn off -Wmaybe-uninitialized
      when building with -Os"), I turned off the warning for any build that
      was done with CC_OPTIMIZE_FOR_SIZE.  This drastically reduced the number
      of false positive warnings in the default build but unfortunately had
      the side effect of turning the warning off completely in 'allmodconfig'
      builds, which in turn led to a lot of warnings (both actual bugs, and
      remaining false positives) to go in unnoticed.
      
      With commit 877417e6 ("Kbuild: change CC_OPTIMIZE_FOR_SIZE
      definition") enabled the warning again for allmodconfig builds in v4.7
      and in v4.8-rc1, I had finally managed to address all warnings I get in
      an ARM allmodconfig build and most other maybe-uninitialized warnings
      for ARM randconfig builds.
      
      However, commit 6e8d666e ("Disable "maybe-uninitialized" warning
      globally") was merged at the same time and disabled it completely for
      all configurations, because of false-positive warnings on x86 that I had
      not addressed until then.  This caused a lot of actual bugs to get
      merged into mainline, and I sent several dozen patches for these during
      the v4.9 development cycle.  Most of these are actual bugs, some are for
      correct code that is safe because it is only called under external
      constraints that make it impossible to run into the case that gcc sees,
      and in a few cases gcc is just stupid and finds something that can
      obviously never happen.
      
      I have now done a few thousand randconfig builds on x86 and collected
      all patches that I needed to address every single warning I got (I can
      provide the combined patch for the other warnings if anyone is
      interested), so I hope we can get the warning back and let people catch
      the actual bugs earlier.
      
      This reverts the change to disable the warning completely and for now
      brings it back at the "make W=1" level, so we can get it merged into
      mainline without introducing false positives.  A follow-up patch enables
      it on all levels unless some configuration option turns it off because
      of false-positives.
      
      Link: https://rusty.ozlabs.org/?p=232 [1]
      Link: https://gcc.gnu.org/wiki/Better_Uninitialized_Warnings [2]
      Signed-off-by: NArnd Bergmann <arnd@arndb.de>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      a76bcf55
    • J
      mm: kmemleak: scan .data.ro_after_init · d7c19b06
      Jakub Kicinski 提交于
      Limit the number of kmemleak false positives by including
      .data.ro_after_init in memory scanning.  To achieve this we need to add
      symbols for start and end of the section to the linker scripts.
      
      The problem was been uncovered by commit 56989f6d ("genetlink: mark
      families as __ro_after_init").
      
      Link: http://lkml.kernel.org/r/1478274173-15218-1-git-send-email-jakub.kicinski@netronome.comReviewed-by: NCatalin Marinas <catalin.marinas@arm.com>
      Signed-off-by: NJakub Kicinski <jakub.kicinski@netronome.com>
      Cc: Arnd Bergmann <arnd@arndb.de>
      Cc: Cong Wang <xiyou.wangcong@gmail.com>
      Cc: Johannes Berg <johannes@sipsolutions.net>
      Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
      Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      d7c19b06
  4. 11 11月, 2016 1 次提交
  5. 09 11月, 2016 5 次提交
  6. 08 11月, 2016 2 次提交
    • V
      ARC: timer: rtc: implement read loop in "C" vs. inline asm · 922cc171
      Vineet Gupta 提交于
      The current code doesn't even compile as somehow the inline assembly
      can't see the register names defined as ARC_RTC_*
      I'm pretty sure It worked when I first got it merged, but the tools were
      definitely different then.
      
      So better to write this in "C" anyways.
      
      CC: stable@vger.kernel.org	#4.2+
      Acked-by: NDaniel Lezcano <daniel.lezcano@linaro.org>
      Signed-off-by: NVineet Gupta <vgupta@synopsys.com>
      922cc171
    • V
      ARC: change return value of userspace cmpxchg assist syscall · e6e335bf
      Vineet Gupta 提交于
      The original syscall only used to return errno to indicate if cmpxchg
      succeeded. It was not returning the "previous" value which typical cmpxchg
      callers are interested in to build their slowpaths or retry loops.
      Given user preemption in syscall return path etc, it is not wise to
      check this in userspace afterwards, but should be what kernel actually
      observed in the syscall.
      
      So change the syscall interface to always return the previous value and
      additionally set Z flag to indicate whether operation succeeded or not
      (just like ARM implementation when they used to have this syscall)
      The flag approach avoids having to put_user errno which is nice given
      the use case for this syscall cares mostly about the "previous" value.
      Signed-off-by: NVineet Gupta <vgupta@synopsys.com>
      e6e335bf
  7. 07 11月, 2016 1 次提交
    • G
      openrisc: Define __ro_after_init to avoid crash · 2c7a5c5c
      Guenter Roeck 提交于
      openrisc qemu tests fail with the following crash.
      
      Unable to handle kernel access at virtual address 0xc0300c34
      
      Oops#: 0001
      CPU #: 0
         PC: c016c710    SR: 0000ae67    SP: c1017e04
         GPR00: 00000000 GPR01: c1017e04 GPR02: c0300c34 GPR03: c0300c34
         GPR04: 00000000 GPR05: c0300cb0 GPR06: c0300c34 GPR07: 000000ff
         GPR08: c107f074 GPR09: c0199ef4 GPR10: c1016000 GPR11: 00000000
         GPR12: 00000000 GPR13: c107f044 GPR14: c0473774 GPR15: 07ce0000
         GPR16: 00000000 GPR17: c107ed8a GPR18: 00009600 GPR19: c107f044
         GPR20: c107ee74 GPR21: 00000003 GPR22: c0473770 GPR23: 00000033
         GPR24: 000000bf GPR25: 00000019 GPR26: c046400c GPR27: 00000001
         GPR28: c0464028 GPR29: c1018000 GPR30: 00000006 GPR31: ccf37483
           RES: 00000000 oGPR11: ffffffff
           Process swapper (pid: 1, stackpage=c1001960)
      
           Stack: Stack dump [0xc1017cf8]:
           sp + 00: 0xc1017e04
           sp + 04: 0xc0300c34
           sp + 08: 0xc0300c34
           sp + 12: 0x00000000
      ...
      
      Bisect points to commit d2ec3f77 ("pty: make ptmx file ops read-only
      after init"). Fix by defining __ro_after_init for the openrisc
      architecture, similar to parisc.
      
      Fixes: d2ec3f77 ("pty: make ptmx file ops read-only after init")
      Cc: Kees Cook <keescook@chromium.org>
      Signed-off-by: NGuenter Roeck <linux@roeck-us.net>
      Acked-by: NStafford Horne <shorne@gmail.com>
      2c7a5c5c
  8. 06 11月, 2016 1 次提交
  9. 05 11月, 2016 1 次提交
    • M
      arm/arm64: KVM: Perform local TLB invalidation when multiplexing vcpus on a single CPU · 94d0e598
      Marc Zyngier 提交于
      Architecturally, TLBs are private to the (physical) CPU they're
      associated with. But when multiple vcpus from the same VM are
      being multiplexed on the same CPU, the TLBs are not private
      to the vcpus (and are actually shared across the VMID).
      
      Let's consider the following scenario:
      
      - vcpu-0 maps PA to VA
      - vcpu-1 maps PA' to VA
      
      If run on the same physical CPU, vcpu-1 can hit TLB entries generated
      by vcpu-0 accesses, and access the wrong physical page.
      
      The solution to this is to keep a per-VM map of which vcpu ran last
      on each given physical CPU, and invalidate local TLBs when switching
      to a different vcpu from the same VM.
      Reviewed-by: NChristoffer Dall <christoffer.dall@linaro.org>
      Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>
      94d0e598
  10. 04 11月, 2016 14 次提交