1. 07 4月, 2018 1 次提交
    • M
      kbuild: mark $(targets) as .SECONDARY and remove .PRECIOUS markers · 54a702f7
      Masahiro Yamada 提交于
      GNU Make automatically deletes intermediate files that are updated
      in a chain of pattern rules.
      
      Example 1) %.dtb.o <- %.dtb.S <- %.dtb <- %.dts
      Example 2) %.o <- %.c <- %.c_shipped
      
      A couple of makefiles mark such targets as .PRECIOUS to prevent Make
      from deleting them, but the correct way is to use .SECONDARY.
      
        .SECONDARY
          Prerequisites of this special target are treated as intermediate
          files but are never automatically deleted.
      
        .PRECIOUS
          When make is interrupted during execution, it may delete the target
          file it is updating if the file was modified since make started.
          If you mark the file as precious, make will never delete the file
          if interrupted.
      
      Both can avoid deletion of intermediate files, but the difference is
      the behavior when Make is interrupted; .SECONDARY deletes the target,
      but .PRECIOUS does not.
      
      The use of .PRECIOUS is relatively rare since we do not want to keep
      partially constructed (possibly corrupted) targets.
      
      Another difference is that .PRECIOUS works with pattern rules whereas
      .SECONDARY does not.
      
        .PRECIOUS: $(obj)/%.lex.c
      
      works, but
      
        .SECONDARY: $(obj)/%.lex.c
      
      has no effect.  However, for the reason above, I do not want to use
      .PRECIOUS which could cause obscure build breakage.
      
      The targets specified as .SECONDARY must be explicit.  $(targets)
      contains all targets that need to include .*.cmd files.  So, the
      intermediates you want to keep are mostly in there.  Therefore, mark
      $(targets) as .SECONDARY.  It means primary targets are also marked
      as .SECONDARY, but I do not see any drawback for this.
      
      I replaced some .SECONDARY / .PRECIOUS markers with 'targets'.  This
      will make Kbuild search for non-existing .*.cmd files, but this is
      not a noticeable performance issue.
      Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
      Acked-by: NFrank Rowand <frowand.list@gmail.com>
      Acked-by: NIngo Molnar <mingo@kernel.org>
      54a702f7
  2. 20 3月, 2018 1 次提交
  3. 07 12月, 2017 1 次提交
    • A
      x86/vdso: Change time() prototype to match __vdso_time() · 88edb57d
      Arnd Bergmann 提交于
      gcc-8 warns that time() is an alias for __vdso_time() but the two
      have different prototypes:
      
        arch/x86/entry/vdso/vclock_gettime.c:327:5: error: 'time' alias between functions of incompatible types 'int(time_t *)' {aka 'int(long int *)'} and 'time_t(time_t *)' {aka 'long int(long int *)'} [-Werror=attribute-alias]
         int time(time_t *t)
             ^~~~
        arch/x86/entry/vdso/vclock_gettime.c:318:16: note: aliased declaration here
      
      I could not figure out whether this is intentional, but I see that
      changing it to return time_t avoids the warning.
      
      Returning 'int' from time() is also a bit questionable, as it causes an
      overflow in y2038 even on 64-bit architectures that use a 64-bit time_t
      type. On 32-bit architecture with 64-bit time_t, time() should always
      be implement by the C library by calling a (to be added) clock_gettime()
      variant that takes a sufficiently wide argument.
      Signed-off-by: NArnd Bergmann <arnd@arndb.de>
      Acked-by: NThomas Gleixner <tglx@linutronix.de>
      Cc: Andy Lutomirski <luto@amacapital.net>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Mark Rutland <mark.rutland@arm.com>
      Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
      Link: http://lkml.kernel.org/r/20171204150203.852959-1-arnd@arndb.deSigned-off-by: NIngo Molnar <mingo@kernel.org>
      88edb57d
  4. 16 11月, 2017 1 次提交
    • M
      kbuild: create object directories simpler and faster · 8a78756e
      Masahiro Yamada 提交于
      For the out-of-tree build, scripts/Makefile.build creates output
      directories, but this operation is not efficient.
      
      scripts/Makefile.lib calculates obj-dirs as follows:
      
        obj-dirs := $(dir $(multi-objs) $(obj-y))
      
      Please notice $(sort ...) is not used here.  Usually the result is
      as many "./" as objects here.
      
      For a lot of duplicated paths, the following command is invoked.
      
        _dummy := $(foreach d,$(obj-dirs), $(shell [ -d $(d) ] || mkdir -p $(d)))
      
      Then, the costly shell command is run over and over again.
      
      I see many points for optimization:
      
      [1] Use $(sort ...) to cut down duplicated paths before passing them
          to system call
      [2] Use single $(shell ...) instead of repeating it with $(foreach ...)
          This will reduce forking.
      [3] We can calculate obj-dirs more simply.  Most of objects are already
          accumulated in $(targets).  So, $(dir $(targets)) is fine and more
          comprehensive.
      
      I also removed ugly code in arch/x86/entry/vdso/Makefile.  This is now
      really unnecessary.
      Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
      Acked-by: NIngo Molnar <mingo@kernel.org>
      Tested-by: NDouglas Anderson <dianders@chromium.org>
      8a78756e
  5. 09 11月, 2017 1 次提交
  6. 07 11月, 2017 1 次提交
  7. 02 11月, 2017 1 次提交
    • G
      License cleanup: add SPDX GPL-2.0 license identifier to files with no license · b2441318
      Greg Kroah-Hartman 提交于
      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: NKate Stewart <kstewart@linuxfoundation.org>
      Reviewed-by: NPhilippe Ombredanne <pombredanne@nexb.com>
      Reviewed-by: NThomas Gleixner <tglx@linutronix.de>
      Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      b2441318
  8. 25 10月, 2017 1 次提交
    • M
      locking/atomics: COCCINELLE/treewide: Convert trivial ACCESS_ONCE() patterns... · 6aa7de05
      Mark Rutland 提交于
      locking/atomics: COCCINELLE/treewide: Convert trivial ACCESS_ONCE() patterns to READ_ONCE()/WRITE_ONCE()
      
      Please do not apply this to mainline directly, instead please re-run the
      coccinelle script shown below and apply its output.
      
      For several reasons, it is desirable to use {READ,WRITE}_ONCE() in
      preference to ACCESS_ONCE(), and new code is expected to use one of the
      former. So far, there's been no reason to change most existing uses of
      ACCESS_ONCE(), as these aren't harmful, and changing them results in
      churn.
      
      However, for some features, the read/write distinction is critical to
      correct operation. To distinguish these cases, separate read/write
      accessors must be used. This patch migrates (most) remaining
      ACCESS_ONCE() instances to {READ,WRITE}_ONCE(), using the following
      coccinelle script:
      
      ----
      // Convert trivial ACCESS_ONCE() uses to equivalent READ_ONCE() and
      // WRITE_ONCE()
      
      // $ make coccicheck COCCI=/home/mark/once.cocci SPFLAGS="--include-headers" MODE=patch
      
      virtual patch
      
      @ depends on patch @
      expression E1, E2;
      @@
      
      - ACCESS_ONCE(E1) = E2
      + WRITE_ONCE(E1, E2)
      
      @ depends on patch @
      expression E;
      @@
      
      - ACCESS_ONCE(E)
      + READ_ONCE(E)
      ----
      Signed-off-by: NMark Rutland <mark.rutland@arm.com>
      Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: davem@davemloft.net
      Cc: linux-arch@vger.kernel.org
      Cc: mpe@ellerman.id.au
      Cc: shuah@kernel.org
      Cc: snitzer@redhat.com
      Cc: thor.thayer@linux.intel.com
      Cc: tj@kernel.org
      Cc: viro@zeniv.linux.org.uk
      Cc: will.deacon@arm.com
      Link: http://lkml.kernel.org/r/1508792849-3115-19-git-send-email-paulmck@linux.vnet.ibm.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      6aa7de05
  9. 19 10月, 2017 1 次提交
  10. 29 8月, 2017 1 次提交
    • T
      x86/gdt: Use bitfields for initialization · 38e9e81f
      Thomas Gleixner 提交于
      The GDT entry related code uses two ways to access entries via
      union fields:
      
       - bitfields
      
       - macros which initialize the two 16-bit parts of the entry
         by magic shift and mask operations.
      
      Clean it up and only use the bitfields to initialize and access entries.
      
      ( The old access patterns were partly done due to GCC optimizing bitfield
        accesses in a horrible way - that's mostly fixed these days and clarity
        of code in such low level accessors is very important. )
      Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
      Cc: Andy 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: Peter Zijlstra <peterz@infradead.org>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Link: http://lkml.kernel.org/r/20170828064958.197673367@linutronix.deSigned-off-by: NIngo Molnar <mingo@kernel.org>
      38e9e81f
  11. 21 6月, 2017 1 次提交
    • D
      ARM: 8683/1: ARM32: Support mremap() for sigpage/vDSO · 280e87e9
      Dmitry Safonov 提交于
      CRIU restores application mappings on the same place where they
      were before Checkpoint. That means, that we need to move vDSO
      and sigpage during restore on exactly the same place where
      they were before C/R.
      
      Make mremap() code update mm->context.{sigpage,vdso} pointers
      during VMA move. Sigpage is used for landing after handling
      a signal - if the pointer is not updated during moving, the
      application might crash on any signal after mremap().
      
      vDSO pointer on ARM32 is used only for setting auxv at this moment,
      update it during mremap() in case of future usage.
      
      Without those updates, current work of CRIU on ARM32 is not reliable.
      Historically, we error Checkpointing if we find vDSO page on ARM32
      and suggest user to disable CONFIG_VDSO.
      But that's not correct - it goes from x86 where signal processing
      is ended in vDSO blob. For arm32 it's sigpage, which is not disabled
      with `CONFIG_VDSO=n'.
      
      Looks like C/R was working by luck - because userspace on ARM32 at
      this moment always sets SA_RESTORER.
      Signed-off-by: NDmitry Safonov <dsafonov@virtuozzo.com>
      Acked-by: NAndy Lutomirski <luto@amacapital.net>
      Cc: linux-arm-kernel@lists.infradead.org
      Cc: Will Deacon <will.deacon@arm.com>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Cyrill Gorcunov <gorcunov@openvz.org>
      Cc: Pavel Emelyanov <xemul@virtuozzo.com>
      Cc: Christopher Covington <cov@codeaurora.org>
      Signed-off-by: NRussell King <rmk+kernel@armlinux.org.uk>
      280e87e9
  12. 11 4月, 2017 1 次提交
  13. 16 3月, 2017 1 次提交
    • T
      x86: Remap GDT tables in the fixmap section · 69218e47
      Thomas Garnier 提交于
      Each processor holds a GDT in its per-cpu structure. The sgdt
      instruction gives the base address of the current GDT. This address can
      be used to bypass KASLR memory randomization. With another bug, an
      attacker could target other per-cpu structures or deduce the base of
      the main memory section (PAGE_OFFSET).
      
      This patch relocates the GDT table for each processor inside the
      fixmap section. The space is reserved based on number of supported
      processors.
      
      For consistency, the remapping is done by default on 32 and 64-bit.
      
      Each processor switches to its remapped GDT at the end of
      initialization. For hibernation, the main processor returns with the
      original GDT and switches back to the remapping at completion.
      
      This patch was tested on both architectures. Hibernation and KVM were
      both tested specially for their usage of the GDT.
      
      Thanks to Boris Ostrovsky <boris.ostrovsky@oracle.com> for testing and
      recommending changes for Xen support.
      Signed-off-by: NThomas Garnier <thgarnie@google.com>
      Cc: Alexander Potapenko <glider@google.com>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
      Cc: Andy Lutomirski <luto@kernel.org>
      Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
      Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
      Cc: Borislav Petkov <bp@suse.de>
      Cc: Chris Wilson <chris@chris-wilson.co.uk>
      Cc: Christian Borntraeger <borntraeger@de.ibm.com>
      Cc: Dmitry Vyukov <dvyukov@google.com>
      Cc: Frederic Weisbecker <fweisbec@gmail.com>
      Cc: Jiri Kosina <jikos@kernel.org>
      Cc: Joerg Roedel <joro@8bytes.org>
      Cc: Jonathan Corbet <corbet@lwn.net>
      Cc: Josh Poimboeuf <jpoimboe@redhat.com>
      Cc: Juergen Gross <jgross@suse.com>
      Cc: Kees Cook <keescook@chromium.org>
      Cc: Len Brown <len.brown@intel.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Lorenzo Stoakes <lstoakes@gmail.com>
      Cc: Luis R . Rodriguez <mcgrof@kernel.org>
      Cc: Matt Fleming <matt@codeblueprint.co.uk>
      Cc: Michal Hocko <mhocko@suse.com>
      Cc: Paolo Bonzini <pbonzini@redhat.com>
      Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
      Cc: Pavel Machek <pavel@ucw.cz>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Radim Krčmář <rkrcmar@redhat.com>
      Cc: Rafael J . Wysocki <rjw@rjwysocki.net>
      Cc: Rusty Russell <rusty@rustcorp.com.au>
      Cc: Stanislaw Gruszka <sgruszka@redhat.com>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Tim Chen <tim.c.chen@linux.intel.com>
      Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
      Cc: kasan-dev@googlegroups.com
      Cc: kernel-hardening@lists.openwall.com
      Cc: kvm@vger.kernel.org
      Cc: lguest@lists.ozlabs.org
      Cc: linux-doc@vger.kernel.org
      Cc: linux-efi@vger.kernel.org
      Cc: linux-mm@kvack.org
      Cc: linux-pm@vger.kernel.org
      Cc: xen-devel@lists.xenproject.org
      Cc: zijun_hu <zijun_hu@htc.com>
      Link: http://lkml.kernel.org/r/20170314170508.100882-2-thgarnie@google.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      69218e47
  14. 11 3月, 2017 1 次提交
  15. 02 3月, 2017 1 次提交
  16. 25 2月, 2017 1 次提交
  17. 25 12月, 2016 2 次提交
  18. 15 12月, 2016 1 次提交
  19. 28 10月, 2016 1 次提交
    • D
      x86/vdso: Set vDSO pointer only after success · 67dece7d
      Dmitry Safonov 提交于
      Those pointers were initialized before call to _install_special_mapping()
      after the commit:
      
        f7b6eb3f ("x86: Set context.vdso before installing the mapping")
      
      This is not required anymore as special mappings have their vma name and
      don't use arch_vma_name() after commit:
      
        a62c34bd ("x86, mm: Improve _install_special_mapping and fix x86 vdso naming")
      
      So, this way to init looks less entangled.
      
      I even belive that we can remove NULL initializers:
      
       - on failure load_elf_binary() will not start a new thread;
       - arch_prctl will have the same pointers as before syscall.
      Signed-off-by: NDmitry Safonov <dsafonov@virtuozzo.com>
      Acked-by: NAndy Lutomirski <luto@kernel.org>
      Cc: 0x7f454c46@gmail.com
      Cc: Borislav Petkov <bp@alien8.de>
      Cc: Brian Gerst <brgerst@gmail.com>
      Cc: Cyrill Gorcunov <gorcunov@openvz.org>
      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: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: linux-mm@kvack.org
      Cc: oleg@redhat.com
      Link: http://lkml.kernel.org/r/20161027141516.28447-3-dsafonov@virtuozzo.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      67dece7d
  20. 30 9月, 2016 1 次提交
  21. 20 9月, 2016 1 次提交
    • P
      KVM: x86: introduce get_kvmclock_ns · 108b249c
      Paolo Bonzini 提交于
      Introduce a function that reads the exact nanoseconds value that is
      provided to the guest in kvmclock.  This crystallizes the notion of
      kvmclock as a thin veneer over a stable TSC, that the guest will
      (hopefully) convert with NTP.  In other words, kvmclock is *not* a
      paravirtualized host-to-guest NTP.
      
      Drop the get_kernel_ns() function, that was used both to get the base
      value of the master clock and to get the current value of kvmclock.
      The former use is replaced by ktime_get_boot_ns(), the latter is
      the purpose of get_kernel_ns().
      
      This also allows KVM to provide a Hyper-V time reference counter that
      is synchronized with the time that is computed from the TSC page.
      Reviewed-by: NRoman Kagan <rkagan@virtuozzo.com>
      Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      108b249c
  22. 15 9月, 2016 4 次提交
  23. 04 8月, 2016 2 次提交
  24. 25 7月, 2016 1 次提交
  25. 19 7月, 2016 1 次提交
  26. 14 7月, 2016 1 次提交
  27. 08 7月, 2016 1 次提交
    • D
      x86/vdso: Add mremap hook to vm_special_mapping · b059a453
      Dmitry Safonov 提交于
      Add possibility for 32-bit user-space applications to move
      the vDSO mapping.
      
      Previously, when a user-space app called mremap() for the vDSO
      address, in the syscall return path it would land on the previous
      address of the vDSOpage, resulting in segmentation violation.
      
      Now it lands fine and returns to userspace with a remapped vDSO.
      
      This will also fix the context.vdso pointer for 64-bit, which does
      not affect the user of vDSO after mremap() currently, but this
      may change in the future.
      
      As suggested by Andy, return -EINVAL for mremap() that would
      split the vDSO image: that operation cannot possibly result in
      a working system so reject it.
      
      Renamed and moved the text_mapping structure declaration inside
      map_vdso(), as it used only there and now it complements the
      vvar_mapping variable.
      
      There is still a problem for remapping the vDSO in glibc
      applications: the linker relocates addresses for syscalls
      on the vDSO page, so you need to relink with the new
      addresses.
      
      Without that the next syscall through glibc may fail:
      
        Program received signal SIGSEGV, Segmentation fault.
        #0  0xf7fd9b80 in __kernel_vsyscall ()
        #1  0xf7ec8238 in _exit () from /usr/lib32/libc.so.6
      Signed-off-by: NDmitry Safonov <dsafonov@virtuozzo.com>
      Acked-by: NAndy Lutomirski <luto@kernel.org>
      Cc: 0x7f454c46@gmail.com
      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: Peter Zijlstra <peterz@infradead.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: linux-mm@kvack.org
      Link: http://lkml.kernel.org/r/20160628113539.13606-2-dsafonov@virtuozzo.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      b059a453
  28. 14 6月, 2016 1 次提交
  29. 08 6月, 2016 1 次提交
    • 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
  30. 24 5月, 2016 1 次提交
  31. 20 4月, 2016 1 次提交
  32. 13 4月, 2016 1 次提交
    • A
      x86/vdso: Remove direct HPET access through the vDSO · 1ed95e52
      Andy Lutomirski 提交于
      Allowing user code to map the HPET is problematic.  HPET
      implementations are notoriously buggy, and there are probably many
      machines on which even MMIO reads from bogus HPET addresses are
      problematic.
      
      We have a report that the Dell Precision M2800 with:
      
        ACPI: HPET 0x00000000C8FE6238 000038 (v01 DELL   CBX3  01072009 AMI. 00000005)
      
      is either so slow when accessing the HPET or actually hangs in some
      regard, causing soft lockups to be reported if users do unexpected
      things to the HPET.
      
      The vclock HPET code has also always been a questionable speedup.
      Accessing an HPET is exceedingly slow (on the order of several
      microseconds), so the added overhead in requiring a syscall to read
      the HPET is a small fraction of the total code of accessing it.
      
      To avoid future problems, let's just delete the code entirely.
      
      In the long run, this could actually be a speedup.  Waiman Long as a
      patch to optimize the case where multiple CPUs contend for the HPET,
      but that won't help unless all the accesses are mediated by the
      kernel.
      Reported-by: NRasmus Villemoes <linux@rasmusvillemoes.dk>
      Signed-off-by: NAndy Lutomirski <luto@kernel.org>
      Reviewed-by: NThomas Gleixner <tglx@linutronix.de>
      Acked-by: NBorislav Petkov <bp@alien8.de>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Waiman Long <Waiman.Long@hpe.com>
      Cc: Waiman Long <waiman.long@hpe.com>
      Link: http://lkml.kernel.org/r/d2f90bba98db9905041cff294646d290d378f67a.1460074438.git.luto@kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
      1ed95e52
  33. 23 3月, 2016 1 次提交
    • D
      kernel: add kcov code coverage · 5c9a8750
      Dmitry Vyukov 提交于
      kcov provides code coverage collection for coverage-guided fuzzing
      (randomized testing).  Coverage-guided fuzzing is a testing technique
      that uses coverage feedback to determine new interesting inputs to a
      system.  A notable user-space example is AFL
      (http://lcamtuf.coredump.cx/afl/).  However, this technique is not
      widely used for kernel testing due to missing compiler and kernel
      support.
      
      kcov does not aim to collect as much coverage as possible.  It aims to
      collect more or less stable coverage that is function of syscall inputs.
      To achieve this goal it does not collect coverage in soft/hard
      interrupts and instrumentation of some inherently non-deterministic or
      non-interesting parts of kernel is disbled (e.g.  scheduler, locking).
      
      Currently there is a single coverage collection mode (tracing), but the
      API anticipates additional collection modes.  Initially I also
      implemented a second mode which exposes coverage in a fixed-size hash
      table of counters (what Quentin used in his original patch).  I've
      dropped the second mode for simplicity.
      
      This patch adds the necessary support on kernel side.  The complimentary
      compiler support was added in gcc revision 231296.
      
      We've used this support to build syzkaller system call fuzzer, which has
      found 90 kernel bugs in just 2 months:
      
        https://github.com/google/syzkaller/wiki/Found-Bugs
      
      We've also found 30+ bugs in our internal systems with syzkaller.
      Another (yet unexplored) direction where kcov coverage would greatly
      help is more traditional "blob mutation".  For example, mounting a
      random blob as a filesystem, or receiving a random blob over wire.
      
      Why not gcov.  Typical fuzzing loop looks as follows: (1) reset
      coverage, (2) execute a bit of code, (3) collect coverage, repeat.  A
      typical coverage can be just a dozen of basic blocks (e.g.  an invalid
      input).  In such context gcov becomes prohibitively expensive as
      reset/collect coverage steps depend on total number of basic
      blocks/edges in program (in case of kernel it is about 2M).  Cost of
      kcov depends only on number of executed basic blocks/edges.  On top of
      that, kernel requires per-thread coverage because there are always
      background threads and unrelated processes that also produce coverage.
      With inlined gcov instrumentation per-thread coverage is not possible.
      
      kcov exposes kernel PCs and control flow to user-space which is
      insecure.  But debugfs should not be mapped as user accessible.
      
      Based on a patch by Quentin Casasnovas.
      
      [akpm@linux-foundation.org: make task_struct.kcov_mode have type `enum kcov_mode']
      [akpm@linux-foundation.org: unbreak allmodconfig]
      [akpm@linux-foundation.org: follow x86 Makefile layout standards]
      Signed-off-by: NDmitry Vyukov <dvyukov@google.com>
      Reviewed-by: NKees Cook <keescook@chromium.org>
      Cc: syzkaller <syzkaller@googlegroups.com>
      Cc: Vegard Nossum <vegard.nossum@oracle.com>
      Cc: Catalin Marinas <catalin.marinas@arm.com>
      Cc: Tavis Ormandy <taviso@google.com>
      Cc: Will Deacon <will.deacon@arm.com>
      Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
      Cc: Kostya Serebryany <kcc@google.com>
      Cc: Eric Dumazet <edumazet@google.com>
      Cc: Alexander Potapenko <glider@google.com>
      Cc: Kees Cook <keescook@google.com>
      Cc: Bjorn Helgaas <bhelgaas@google.com>
      Cc: Sasha Levin <sasha.levin@oracle.com>
      Cc: David Drysdale <drysdale@google.com>
      Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
      Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
      Cc: Kirill A. Shutemov <kirill@shutemov.name>
      Cc: Jiri Slaby <jslaby@suse.cz>
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: "H. Peter Anvin" <hpa@zytor.com>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      5c9a8750
  34. 29 2月, 2016 1 次提交
    • J
      objtool: Mark non-standard object files and directories · c0dd6716
      Josh Poimboeuf 提交于
      Code which runs outside the kernel's normal mode of operation often does
      unusual things which can cause a static analysis tool like objtool to
      emit false positive warnings:
      
       - boot image
       - vdso image
       - relocation
       - realmode
       - efi
       - head
       - purgatory
       - modpost
      
      Set OBJECT_FILES_NON_STANDARD for their related files and directories,
      which will tell objtool to skip checking them.  It's ok to skip them
      because they don't affect runtime stack traces.
      
      Also skip the following code which does the right thing with respect to
      frame pointers, but is too "special" to be validated by a tool:
      
       - entry
       - mcount
      
      Also skip the test_nx module because it modifies its exception handling
      table at runtime, which objtool can't understand.  Fortunately it's
      just a test module so it doesn't matter much.
      
      Currently objtool is the only user of OBJECT_FILES_NON_STANDARD, but it
      might eventually be useful for other tools.
      Signed-off-by: NJosh Poimboeuf <jpoimboe@redhat.com>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Andy Lutomirski <luto@kernel.org>
      Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
      Cc: Bernd Petrovitsch <bernd@petrovitsch.priv.at>
      Cc: Borislav Petkov <bp@alien8.de>
      Cc: Chris J Arges <chris.j.arges@canonical.com>
      Cc: Jiri Slaby <jslaby@suse.cz>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Michal Marek <mmarek@suse.cz>
      Cc: Namhyung Kim <namhyung@gmail.com>
      Cc: Pedro Alves <palves@redhat.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: live-patching@vger.kernel.org
      Link: http://lkml.kernel.org/r/366c080e3844e8a5b6a0327dc7e8c2b90ca3baeb.1456719558.git.jpoimboe@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      c0dd6716
  35. 24 2月, 2016 1 次提交