1. 25 Mar, 2018 1 commit
    • Nicholas Piggin's avatar
      kbuild: rename built-in.o to built-in.a · f49821ee
      Nicholas Piggin authored
      Incremental linking is gone, so rename built-in.o to built-in.a, which
      is the usual extension for archive files.
      
      This patch does two things, first is a simple search/replace:
      
      git grep -l 'built-in\.o' | xargs sed -i 's/built-in\.o/built-in\.a/g'
      
      The second is to invert nesting of nested text manipulations to avoid
      filtering built-in.a out from libs-y2:
      
      -libs-y2 := $(filter-out %.a, $(patsubst %/, %/built-in.a, $(libs-y)))
      +libs-y2 := $(patsubst %/, %/built-in.a, $(filter-out %.a, $(libs-y)))
      Signed-off-by: default avatarNicholas Piggin <npiggin@gmail.com>
      Signed-off-by: default avatarMasahiro Yamada <yamada.masahiro@socionext.com>
      f49821ee
  2. 12 Nov, 2017 1 commit
  3. 02 Nov, 2017 1 commit
    • Greg Kroah-Hartman's avatar
      License cleanup: add SPDX GPL-2.0 license identifier to files with no license · b2441318
      Greg Kroah-Hartman authored
      Many source files in the tree are missing licensing information, which
      makes it harder for compliance tools to determine the correct license.
      
      By default all files without license information are under the default
      license of the kernel, which is GPL version 2.
      
      Update the files which contain no license information with the 'GPL-2.0'
      SPDX license identifier.  The SPDX identifier is a legally binding
      shorthand, which can be used instead of the full boiler plate text.
      
      This patch is based on work done by Thomas Gleixner and Kate Stewart and
      Philippe Ombredanne.
      
      How this work was done:
      
      Patches were generated and checked against linux-4.14-rc6 for a subset of
      the use cases:
       - file had no licensing information it it.
       - file was a */uapi/* one with no licensing information in it,
       - file was a */uapi/* one with existing licensing information,
      
      Further patches will be generated in subsequent months to fix up cases
      where non-standard license headers were used, and references to license
      had to be inferred by heuristics based on keywords.
      
      The analysis to determine which SPDX License Identifier to be applied to
      a file was done in a spreadsheet of side by side results from of the
      output of two independent scanners (ScanCode & Windriver) producing SPDX
      tag:value files created by Philippe Ombredanne.  Philippe prepared the
      base worksheet, and did an initial spot review of a few 1000 files.
      
      The 4.13 kernel was the starting point of the analysis with 60,537 files
      assessed.  Kate Stewart did a file by file comparison of the scanner
      results in the spreadsheet to determine which SPDX license identifier(s)
      to be applied to the file. She confirmed any determination that was not
      immediately clear with lawyers working with the Linux Foundation.
      
      Criteria used to select files for SPDX license identifier tagging was:
       - Files considered eligible had to be source code files.
       - Make and config files were included as candidates if they contained >5
         lines of source
       - File already had some variant of a license header in it (even if <5
         lines).
      
      All documentation files were explicitly excluded.
      
      The following heuristics were used to determine which SPDX license
      identifiers to apply.
      
       - when both scanners couldn't find any license traces, file was
         considered to have no license information in it, and the top level
         COPYING file license applied.
      
         For non */uapi/* files that summary was:
      
         SPDX license identifier                            # files
         ---------------------------------------------------|-------
         GPL-2.0                                              11139
      
         and resulted in the first patch in this series.
      
         If that file was a */uapi/* path one, it was "GPL-2.0 WITH
         Linux-syscall-note" otherwise it was "GPL-2.0".  Results of that was:
      
         SPDX license identifier                            # files
         ---------------------------------------------------|-------
         GPL-2.0 WITH Linux-syscall-note                        930
      
         and resulted in the second patch in this series.
      
       - if a file had some form of licensing information in it, and was one
         of the */uapi/* ones, it was denoted with the Linux-syscall-note if
         any GPL family license was found in the file or had no licensing in
         it (per prior point).  Results summary:
      
         SPDX license identifier                            # files
         ---------------------------------------------------|------
         GPL-2.0 WITH Linux-syscall-note                       270
         GPL-2.0+ WITH Linux-syscall-note                      169
         ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
         ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
         LGPL-2.1+ WITH Linux-syscall-note                      15
         GPL-1.0+ WITH Linux-syscall-note                       14
         ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
         LGPL-2.0+ WITH Linux-syscall-note                       4
         LGPL-2.1 WITH Linux-syscall-note                        3
         ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
         ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1
      
         and that resulted in the third patch in this series.
      
       - when the two scanners agreed on the detected license(s), that became
         the concluded license(s).
      
       - when there was disagreement between the two scanners (one detected a
         license but the other didn't, or they both detected different
         licenses) a manual inspection of the file occurred.
      
       - In most cases a manual inspection of the information in the file
         resulted in a clear resolution of the license that should apply (and
         which scanner probably needed to revisit its heuristics).
      
       - When it was not immediately clear, the license identifier was
         confirmed with lawyers working with the Linux Foundation.
      
       - If there was any question as to the appropriate license identifier,
         the file was flagged for further research and to be revisited later
         in time.
      
      In total, over 70 hours of logged manual review was done on the
      spreadsheet to determine the SPDX license identifiers to apply to the
      source files by Kate, Philippe, Thomas and, in some cases, confirmation
      by lawyers working with the Linux Foundation.
      
      Kate also obtained a third independent scan of the 4.13 code base from
      FOSSology, and compared selected files where the other two scanners
      disagreed against that SPDX file, to see if there was new insights.  The
      Windriver scanner is based on an older version of FOSSology in part, so
      they are related.
      
      Thomas did random spot checks in about 500 files from the spreadsheets
      for the uapi headers and agreed with SPDX license identifier in the
      files he inspected. For the non-uapi files Thomas did random spot checks
      in about 15000 files.
      
      In initial set of patches against 4.14-rc6, 3 files were found to have
      copy/paste license identifier errors, and have been fixed to reflect the
      correct identifier.
      
      Additionally Philippe spent 10 hours this week doing a detailed manual
      inspection and review of the 12,461 patched files from the initial patch
      version early this week with:
       - a full scancode scan run, collecting the matched texts, detected
         license ids and scores
       - reviewing anything where there was a license detected (about 500+
         files) to ensure that the applied SPDX license was correct
       - reviewing anything where there was no detection but the patch license
         was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
         SPDX license was correct
      
      This produced a worksheet with 20 files needing minor correction.  This
      worksheet was then exported into 3 different .csv files for the
      different types of files to be modified.
      
      These .csv files were then reviewed by Greg.  Thomas wrote a script to
      parse the csv files and add the proper SPDX tag to the file, in the
      format that the file expected.  This script was further refined by Greg
      based on the output to detect more types of files automatically and to
      distinguish between header and source .c files (which need different
      comment types.)  Finally Greg ran the script using the .csv files to
      generate the patches.
      Reviewed-by: default avatarKate Stewart <kstewart@linuxfoundation.org>
      Reviewed-by: default avatarPhilippe Ombredanne <pombredanne@nexb.com>
      Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      b2441318
  4. 10 Aug, 2017 2 commits
  5. 12 Jul, 2017 1 commit
  6. 21 Jun, 2017 1 commit
  7. 09 May, 2017 1 commit
  8. 27 Apr, 2017 1 commit
  9. 24 Apr, 2017 1 commit
  10. 10 Feb, 2017 1 commit
    • Anju T's avatar
      powerpc/kprobes: Implement Optprobes · 51c9c084
      Anju T authored
      Current infrastructure of kprobe uses the unconditional trap instruction
      to probe a running kernel. Optprobe allows kprobe to replace the trap
      with a branch instruction to a detour buffer. Detour buffer contains
      instructions to create an in memory pt_regs. Detour buffer also has a
      call to optimized_callback() which in turn call the pre_handler(). After
      the execution of the pre-handler, a call is made for instruction
      emulation. The NIP is determined in advanced through dummy instruction
      emulation and a branch instruction is created to the NIP at the end of
      the trampoline.
      
      To address the limitation of branch instruction in POWER architecture,
      detour buffer slot is allocated from a reserved area. For the time
      being, 64KB is reserved in memory for this purpose.
      
      Instructions which can be emulated using analyse_instr() are the
      candidates for optimization. Before optimization ensure that the address
      range between the detour buffer allocated and the instruction being
      probed is within +/- 32MB.
      Signed-off-by: default avatarAnju T Sudhakar <anju@linux.vnet.ibm.com>
      Signed-off-by: default avatarNaveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
      Acked-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
      Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      51c9c084
  11. 03 Feb, 2017 1 commit
  12. 24 Jan, 2017 1 commit
    • Michael Ellerman's avatar
      powerpc: Revert the initial stack protector support · f2574030
      Michael Ellerman authored
      Unfortunately the stack protector support we merged recently only works
      on some toolchains. If the toolchain is built without glibc support
      everything works fine, but if glibc is built then it leads to a panic
      at boot.
      
      The solution is not rc5 material, so revert the support for now. This
      reverts commits:
      
      6533b7c1 ("powerpc: Initial stack protector (-fstack-protector) support")
      902e06eb ("powerpc/32: Change the stack protector canary value per task")
      
      Fixes: 6533b7c1 ("powerpc: Initial stack protector (-fstack-protector) support")
      Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      f2574030
  13. 20 Dec, 2016 1 commit
    • Thiago Jung Bauermann's avatar
      powerpc: ima: get the kexec buffer passed by the previous kernel · 467d2782
      Thiago Jung Bauermann authored
      Patch series "ima: carry the measurement list across kexec", v8.
      
      The TPM PCRs are only reset on a hard reboot.  In order to validate a
      TPM's quote after a soft reboot (eg.  kexec -e), the IMA measurement
      list of the running kernel must be saved and then restored on the
      subsequent boot, possibly of a different architecture.
      
      The existing securityfs binary_runtime_measurements file conveniently
      provides a serialized format of the IMA measurement list.  This patch
      set serializes the measurement list in this format and restores it.
      
      Up to now, the binary_runtime_measurements was defined as architecture
      native format.  The assumption being that userspace could and would
      handle any architecture conversions.  With the ability of carrying the
      measurement list across kexec, possibly from one architecture to a
      different one, the per boot architecture information is lost and with it
      the ability of recalculating the template digest hash.  To resolve this
      problem, without breaking the existing ABI, this patch set introduces
      the boot command line option "ima_canonical_fmt", which is arbitrarily
      defined as little endian.
      
      The need for this boot command line option will be limited to the
      existing version 1 format of the binary_runtime_measurements.
      Subsequent formats will be defined as canonical format (eg.  TPM 2.0
      support for larger digests).
      
      A simplified method of Thiago Bauermann's "kexec buffer handover" patch
      series for carrying the IMA measurement list across kexec is included in
      this patch set.  The simplified method requires all file measurements be
      taken prior to executing the kexec load, as subsequent measurements will
      not be carried across the kexec and restored.
      
      This patch (of 10):
      
      The IMA kexec buffer allows the currently running kernel to pass the
      measurement list via a kexec segment to the kernel that will be kexec'd.
      The second kernel can check whether the previous kernel sent the buffer
      and retrieve it.
      
      This is the architecture-specific part which enables IMA to receive the
      measurement list passed by the previous kernel.  It will be used in the
      next patch.
      
      The change in machine_kexec_64.c is to factor out the logic of removing
      an FDT memory reservation so that it can be used by remove_ima_buffer.
      
      Link: http://lkml.kernel.org/r/1480554346-29071-2-git-send-email-zohar@linux.vnet.ibm.comSigned-off-by: default avatarThiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
      Signed-off-by: default avatarMimi Zohar <zohar@linux.vnet.ibm.com>
      Acked-by: default avatar"Eric W. Biederman" <ebiederm@xmission.com>
      Cc: Andreas Steffen <andreas.steffen@strongswan.org>
      Cc: Dmitry Kasatkin <dmitry.kasatkin@gmail.com>
      Cc: Josh Sklar <sklar@linux.vnet.ibm.com>
      Cc: Dave Young <dyoung@redhat.com>
      Cc: Vivek Goyal <vgoyal@redhat.com>
      Cc: Baoquan He <bhe@redhat.com>
      Cc: Michael Ellerman <mpe@ellerman.id.au>
      Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Stewart Smith <stewart@linux.vnet.ibm.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      467d2782
  14. 30 Nov, 2016 2 commits
  15. 23 Nov, 2016 1 commit
  16. 18 Nov, 2016 2 commits
  17. 10 Oct, 2016 1 commit
    • Emese Revfy's avatar
      gcc-plugins: Add latent_entropy plugin · 38addce8
      Emese Revfy authored
      This adds a new gcc plugin named "latent_entropy". It is designed to
      extract as much possible uncertainty from a running system at boot time as
      possible, hoping to capitalize on any possible variation in CPU operation
      (due to runtime data differences, hardware differences, SMP ordering,
      thermal timing variation, cache behavior, etc).
      
      At the very least, this plugin is a much more comprehensive example for
      how to manipulate kernel code using the gcc plugin internals.
      
      The need for very-early boot entropy tends to be very architecture or
      system design specific, so this plugin is more suited for those sorts
      of special cases. The existing kernel RNG already attempts to extract
      entropy from reliable runtime variation, but this plugin takes the idea to
      a logical extreme by permuting a global variable based on any variation
      in code execution (e.g. a different value (and permutation function)
      is used to permute the global based on loop count, case statement,
      if/then/else branching, etc).
      
      To do this, the plugin starts by inserting a local variable in every
      marked function. The plugin then adds logic so that the value of this
      variable is modified by randomly chosen operations (add, xor and rol) and
      random values (gcc generates separate static values for each location at
      compile time and also injects the stack pointer at runtime). The resulting
      value depends on the control flow path (e.g., loops and branches taken).
      
      Before the function returns, the plugin mixes this local variable into
      the latent_entropy global variable. The value of this global variable
      is added to the kernel entropy pool in do_one_initcall() and _do_fork(),
      though it does not credit any bytes of entropy to the pool; the contents
      of the global are just used to mix the pool.
      
      Additionally, the plugin can pre-initialize arrays with build-time
      random contents, so that two different kernel builds running on identical
      hardware will not have the same starting values.
      Signed-off-by: default avatarEmese Revfy <re.emese@gmail.com>
      [kees: expanded commit message and code comments]
      Signed-off-by: default avatarKees Cook <keescook@chromium.org>
      38addce8
  18. 13 Sep, 2016 1 commit
    • Michael Ellerman's avatar
      powerpc/Makefile: Drop CONFIG_WORD_SIZE for BITS · 68201fbb
      Michael Ellerman authored
      Commit 2578bfae ("[POWERPC] Create and use CONFIG_WORD_SIZE") added
      CONFIG_WORD_SIZE, and suggests that other arches were going to do
      likewise.
      
      But that never happened, powerpc is the only architecture which uses it.
      
      So switch to using a simple make variable, BITS, like x86, sh, sparc and
      tile. It is also easier to spell and simpler, avoiding any confusion
      about whether it's defined due to ordering of make vs kconfig.
      Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      68201fbb
  19. 09 Sep, 2016 1 commit
    • Paolo Bonzini's avatar
      powerpc: move hmi.c to arch/powerpc/kvm/ · 3f257774
      Paolo Bonzini authored
      hmi.c functions are unused unless sibling_subcore_state is nonzero, and
      that in turn happens only if KVM is in use.  So move the code to
      arch/powerpc/kvm/, putting it under CONFIG_KVM_BOOK3S_HV_POSSIBLE
      rather than CONFIG_PPC_BOOK3S_64.  The sibling_subcore_state is also
      included in struct paca_struct only if KVM is supported by the kernel.
      
      Cc: Daniel Axtens <dja@axtens.net>
      Cc: Michael Ellerman <mpe@ellerman.id.au>
      Cc: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: linuxppc-dev@lists.ozlabs.org
      Cc: kvm-ppc@vger.kernel.org
      Cc: kvm@vger.kernel.org
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      Signed-off-by: default avatarPaul Mackerras <paulus@ozlabs.org>
      3f257774
  20. 22 Aug, 2016 1 commit
    • Paolo Bonzini's avatar
      powerpc: move hmi.c to arch/powerpc/kvm/ · 7c379526
      Paolo Bonzini authored
      hmi.c functions are unused unless sibling_subcore_state is nonzero, and
      that in turn happens only if KVM is in use.  So move the code to
      arch/powerpc/kvm/, putting it under CONFIG_KVM_BOOK3S_HV_POSSIBLE
      rather than CONFIG_PPC_BOOK3S_64.  The sibling_subcore_state is also
      included in struct paca_struct only if KVM is supported by the kernel.
      
      Cc: Daniel Axtens <dja@axtens.net>
      Cc: Michael Ellerman <mpe@ellerman.id.au>
      Cc: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: linuxppc-dev@lists.ozlabs.org
      Cc: kvm-ppc@vger.kernel.org
      Cc: kvm@vger.kernel.org
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
      7c379526
  21. 08 Aug, 2016 1 commit
  22. 19 Jul, 2016 1 commit
  23. 15 Jul, 2016 1 commit
  24. 20 Jun, 2016 1 commit
    • Mahesh Salgaonkar's avatar
      KVM: PPC: Book3S HV: Fix TB corruption in guest exit path on HMI interrupt · fd7bacbc
      Mahesh Salgaonkar authored
      When a guest is assigned to a core it converts the host Timebase (TB)
      into guest TB by adding guest timebase offset before entering into
      guest. During guest exit it restores the guest TB to host TB. This means
      under certain conditions (Guest migration) host TB and guest TB can differ.
      
      When we get an HMI for TB related issues the opal HMI handler would
      try fixing errors and restore the correct host TB value. With no guest
      running, we don't have any issues. But with guest running on the core
      we run into TB corruption issues.
      
      If we get an HMI while in the guest, the current HMI handler invokes opal
      hmi handler before forcing guest to exit. The guest exit path subtracts
      the guest TB offset from the current TB value which may have already
      been restored with host value by opal hmi handler. This leads to incorrect
      host and guest TB values.
      
      With split-core, things become more complex. With split-core, TB also gets
      split and each subcore gets its own TB register. When a hmi handler fixes
      a TB error and restores the TB value, it affects all the TB values of
      sibling subcores on the same core. On TB errors all the thread in the core
      gets HMI. With existing code, the individual threads call opal hmi handle
      independently which can easily throw TB out of sync if we have guest
      running on subcores. Hence we will need to co-ordinate with all the
      threads before making opal hmi handler call followed by TB resync.
      
      This patch introduces a sibling subcore state structure (shared by all
      threads in the core) in paca which holds information about whether sibling
      subcores are in Guest mode or host mode. An array in_guest[] of size
      MAX_SUBCORE_PER_CORE=4 is used to maintain the state of each subcore.
      The subcore id is used as index into in_guest[] array. Only primary
      thread entering/exiting the guest is responsible to set/unset its
      designated array element.
      
      On TB error, we get HMI interrupt on every thread on the core. Upon HMI,
      this patch will now force guest to vacate the core/subcore. Primary
      thread from each subcore will then turn off its respective bit
      from the above bitmap during the guest exit path just after the
      guest->host partition switch is complete.
      
      All other threads that have just exited the guest OR were already in host
      will wait until all other subcores clears their respective bit.
      Once all the subcores turn off their respective bit, all threads will
      will make call to opal hmi handler.
      
      It is not necessary that opal hmi handler would resync the TB value for
      every HMI interrupts. It would do so only for the HMI caused due to
      TB errors. For rest, it would not touch TB value. Hence to make things
      simpler, primary thread would call TB resync explicitly once for each
      core immediately after opal hmi handler instead of subtracting guest
      offset from TB. TB resync call will restore the TB with host value.
      Thus we can be sure about the TB state.
      
      One of the primary threads exiting the guest will take up the
      responsibility of calling TB resync. It will use one of the top bits
      (bit 63) from subcore state flags bitmap to make the decision. The first
      primary thread (among the subcores) that is able to set the bit will
      have to call the TB resync. Rest all other threads will wait until TB
      resync is complete.  Once TB resync is complete all threads will then
      proceed.
      Signed-off-by: default avatarMahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
      Signed-off-by: default avatarPaul Mackerras <paulus@ozlabs.org>
      fd7bacbc
  25. 07 Mar, 2016 1 commit
  26. 21 Jan, 2016 1 commit
  27. 06 Aug, 2015 1 commit
  28. 05 Jun, 2015 1 commit
  29. 11 May, 2015 1 commit
  30. 17 Mar, 2015 1 commit
  31. 25 Sep, 2014 1 commit
  32. 11 Jun, 2014 1 commit
  33. 30 Apr, 2014 1 commit
  34. 12 Jan, 2014 1 commit
    • Gerhard Sittig's avatar
      clk: mpc5xxx: switch to COMMON_CLK, retire PPC_CLOCK · 7d71d5b2
      Gerhard Sittig authored
      the setup before the change was
      - arch/powerpc/Kconfig had the PPC_CLOCK option, off by default
      - depending on the PPC_CLOCK option the arch/powerpc/kernel/clock.c file
        was built, which implements the clk.h API but always returns -ENOSYS
        unless a platform registers specific callbacks
      - the MPC52xx platform selected PPC_CLOCK but did not register any
        callbacks, thus all clk.h API calls keep resulting in -ENOSYS errors
        (which is OK, all peripheral drivers deal with the situation)
      - the MPC512x platform selected PPC_CLOCK and registered specific
        callbacks implemented in arch/powerpc/platforms/512x/clock.c, thus
        provided real support for the clock API
      - no other powerpc platform did select PPC_CLOCK
      
      the situation after the change is
      - the MPC512x platform implements the COMMON_CLK interface, and thus the
        PPC_CLOCK approach in arch/powerpc/platforms/512x/clock.c has become
        obsolete
      - the MPC52xx platform still lacks genuine support for the clk.h API
        while this is not a change against the previous situation (the error
        code returned from COMMON_CLK stubs differs but every call still
        results in an error)
      - with all references gone, the arch/powerpc/kernel/clock.c wrapper and
        the PPC_CLOCK option have become obsolete, as did the clk_interface.h
        header file
      
      the switch from PPC_CLOCK to COMMON_CLK is done for all platforms within
      the same commit such that multiplatform kernels (the combination of 512x
      and 52xx within one executable) keep working
      
      Cc: Mike Turquette <mturquette@linaro.org>
      Cc: Anatolij Gustschin <agust@denx.de>
      Cc: linux-arm-kernel@lists.infradead.org
      Cc: linuxppc-dev@lists.ozlabs.org
      Signed-off-by: default avatarGerhard Sittig <gsi@denx.de>
      Signed-off-by: default avatarAnatolij Gustschin <agust@denx.de>
      7d71d5b2
  35. 05 Dec, 2013 2 commits
    • Mahesh Salgaonkar's avatar
      powerpc/book3s: Decode and save machine check event. · 36df96f8
      Mahesh Salgaonkar authored
      Now that we handle machine check in linux, the MCE decoding should also
      take place in linux host. This info is crucial to log before we go down
      in case we can not handle the machine check errors. This patch decodes
      and populates a machine check event which contain high level meaning full
      MCE information.
      
      We do this in real mode C code with ME bit on. The MCE information is still
      available on emergency stack (in pt_regs structure format). Even if we take
      another exception at this point the MCE early handler will allocate a new
      stack frame on top of current one. So when we return back here we still have
      our MCE information safe on current stack.
      
      We use per cpu buffer to save high level MCE information. Each per cpu buffer
      is an array of machine check event structure indexed by per cpu counter
      mce_nest_count. The mce_nest_count is incremented every time we enter
      machine check early handler in real mode to get the current free slot
      (index = mce_nest_count - 1). The mce_nest_count is decremented once the
      MCE info is consumed by virtual mode machine exception handler.
      
      This patch provides save_mce_event(), get_mce_event() and release_mce_event()
      generic routines that can be used by machine check handlers to populate and
      retrieve the event. The routine release_mce_event() will free the event slot so
      that it can be reused. Caller can invoke get_mce_event() with a release flag
      either to release the event slot immediately OR keep it so that it can be
      fetched again. The event slot can be also released anytime by invoking
      release_mce_event().
      
      This patch also updates kvm code to invoke get_mce_event to retrieve generic
      mce event rather than paca->opal_mce_evt.
      
      The KVM code always calls get_mce_event() with release flags set to false so
      that event is available for linus host machine
      
      If machine check occurs while we are in guest, KVM tries to handle the error.
      If KVM is able to handle MC error successfully, it enters the guest and
      delivers the machine check to guest. If KVM is not able to handle MC error, it
      exists the guest and passes the control to linux host machine check handler
      which then logs MC event and decides how to handle it in linux host. In failure
      case, KVM needs to make sure that the MC event is available for linux host to
      consume. Hence KVM always calls get_mce_event() with release flags set to false
      and later it invokes release_mce_event() only if it succeeds to handle error.
      Signed-off-by: default avatarMahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
      Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
      36df96f8
    • Mahesh Salgaonkar's avatar
      powerpc/book3s: Flush SLB/TLBs if we get SLB/TLB machine check errors on power7. · e22a2274
      Mahesh Salgaonkar authored
      If we get a machine check exception due to SLB or TLB errors, then flush
      SLBs/TLBs and reload SLBs to recover. We do this in real mode before turning
      on MMU. Otherwise we would run into nested machine checks.
      
      If we get a machine check when we are in guest, then just flush the
      SLBs and continue. This patch handles errors for power7. The next
      patch will handle errors for power8
      Signed-off-by: default avatarMahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
      Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
      Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
      e22a2274
  36. 28 Aug, 2013 1 commit