1. 22 Mar, 2016 1 commit
    • Dmitry Vyukov's avatar
      kernel: add kcov code coverage · 5c9a8750
      Dmitry Vyukov authored
      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
      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:
      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: default avatarDmitry Vyukov <dvyukov@google.com>
      Reviewed-by: default avatarKees 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: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
  2. 23 Feb, 2016 1 commit
  3. 20 Jan, 2016 1 commit
  4. 18 Dec, 2015 1 commit
  5. 25 Nov, 2015 1 commit
    • Michal Marek's avatar
      kbuild: Allow to specify composite modules with modname-m · cf4f2193
      Michal Marek authored
      This allows to write
        drm-$(CONFIG_AGP) += drm_agpsupport.o
      without having to handle CONFIG_AGP=y vs. CONFIG_AGP=m. Only support
      this syntax for modules, since built-in code depending on something
      modular cannot work and init/Makefile actually relies on the current
      semantics. There are a few drivers which adapted to the current
      semantics out of necessity; these are fixed to also work when the
      respective subsystem is modular.
      Acked-by: Peter Chen <peter.chen@freescale.com> [chipidea]
      Signed-off-by: default avatarMichal Marek <mmarek@suse.com>
  6. 03 Apr, 2015 1 commit
  7. 13 Feb, 2015 1 commit
    • Andrey Ryabinin's avatar
      kasan: add kernel address sanitizer infrastructure · 0b24becc
      Andrey Ryabinin authored
      Kernel Address sanitizer (KASan) is a dynamic memory error detector.  It
      provides fast and comprehensive solution for finding use-after-free and
      out-of-bounds bugs.
      KASAN uses compile-time instrumentation for checking every memory access,
      therefore GCC > v4.9.2 required.  v4.9.2 almost works, but has issues with
      putting symbol aliases into the wrong section, which breaks kasan
      instrumentation of globals.
      This patch only adds infrastructure for kernel address sanitizer.  It's
      not available for use yet.  The idea and some code was borrowed from [1].
      Basic idea:
      The main idea of KASAN is to use shadow memory to record whether each byte
      of memory is safe to access or not, and use compiler's instrumentation to
      check the shadow memory on each memory access.
      Address sanitizer uses 1/8 of the memory addressable in kernel for shadow
      memory and uses direct mapping with a scale and offset to translate a
      memory address to its corresponding shadow address.
      Here is function to translate address to corresponding shadow address:
           unsigned long kasan_mem_to_shadow(unsigned long addr)
                      return (addr >> KASAN_SHADOW_SCALE_SHIFT) + KASAN_SHADOW_OFFSET;
      So for every 8 bytes there is one corresponding byte of shadow memory.
      The following encoding used for each shadow byte: 0 means that all 8 bytes
      of the corresponding memory region are valid for access; k (1 <= k <= 7)
      means that the first k bytes are valid for access, and other (8 - k) bytes
      are not; Any negative value indicates that the entire 8-bytes are
      inaccessible.  Different negative values used to distinguish between
      different kinds of inaccessible memory (redzones, freed memory) (see
      To be able to detect accesses to bad memory we need a special compiler.
      Such compiler inserts a specific function calls (__asan_load*(addr),
      __asan_store*(addr)) before each memory access of size 1, 2, 4, 8 or 16.
      These functions check whether memory region is valid to access or not by
      checking corresponding shadow memory.  If access is not valid an error
      Historical background of the address sanitizer from Dmitry Vyukov:
      	"We've developed the set of tools, AddressSanitizer (Asan),
      	ThreadSanitizer and MemorySanitizer, for user space. We actively use
      	them for testing inside of Google (continuous testing, fuzzing,
      	running prod services). To date the tools have found more than 10'000
      	scary bugs in Chromium, Google internal codebase and various
      	open-source projects (Firefox, OpenSSL, gcc, clang, ffmpeg, MySQL and
      	lots of others): [2] [3] [4].
      	The tools are part of both gcc and clang compilers.
      	We have not yet done massive testing under the Kernel AddressSanitizer
      	(it's kind of chicken and egg problem, you need it to be upstream to
      	start applying it extensively). To date it has found about 50 bugs.
      	Bugs that we've found in upstream kernel are listed in [5].
      	We've also found ~20 bugs in out internal version of the kernel. Also
      	people from Samsung and Oracle have found some.
      	As others noted, the main feature of AddressSanitizer is its
      	performance due to inline compiler instrumentation and simple linear
      	shadow memory. User-space Asan has ~2x slowdown on computational
      	programs and ~2x memory consumption increase. Taking into account that
      	kernel usually consumes only small fraction of CPU and memory when
      	running real user-space programs, I would expect that kernel Asan will
      	have ~10-30% slowdown and similar memory consumption increase (when we
      	finish all tuning).
      	I agree that Asan can well replace kmemcheck. We have plans to start
      	working on Kernel MemorySanitizer that finds uses of unitialized
      	memory. Asan+Msan will provide feature-parity with kmemcheck. As
      	others noted, Asan will unlikely replace debug slab and pagealloc that
      	can be enabled at runtime. Asan uses compiler instrumentation, so even
      	if it is disabled, it still incurs visible overheads.
      	Asan technology is easily portable to other architectures. Compiler
      	instrumentation is fully portable. Runtime has some arch-dependent
      	parts like shadow mapping and atomic operation interception. They are
      	relatively easy to port."
      Comparison with other debugging features:
        - KASan can do almost everything that kmemcheck can.  KASan uses
          compile-time instrumentation, which makes it significantly faster than
          kmemcheck.  The only advantage of kmemcheck over KASan is detection of
          uninitialized memory reads.
          Some brief performance testing showed that kasan could be
          x500-x600 times faster than kmemcheck:
      $ netperf -l 30
      		MIGRATED TCP STREAM TEST from ( port 0 AF_INET to localhost ( port 0 AF_INET
      		Recv   Send    Send
      		Socket Socket  Message  Elapsed
      		Size   Size    Size     Time     Throughput
      		bytes  bytes   bytes    secs.    10^6bits/sec
      no debug:	87380  16384  16384    30.00    41624.72
      kasan inline:	87380  16384  16384    30.00    12870.54
      kasan outline:	87380  16384  16384    30.00    10586.39
      kmemcheck: 	87380  16384  16384    30.03      20.23
        - Also kmemcheck couldn't work on several CPUs.  It always sets
          number of CPUs to 1.  KASan doesn't have such limitation.
      	- KASan is slower than DEBUG_PAGEALLOC, but KASan works on sub-page
      	  granularity level, so it able to find more bugs.
      SLUB_DEBUG (poisoning, redzones):
      	- SLUB_DEBUG has lower overhead than KASan.
      	- SLUB_DEBUG in most cases are not able to detect bad reads,
      	  KASan able to detect both reads and writes.
      	- In some cases (e.g. redzone overwritten) SLUB_DEBUG detect
      	  bugs only on allocation/freeing of object. KASan catch
      	  bugs right before it will happen, so we always know exact
      	  place of first bad read/write.
      [1] https://code.google.com/p/address-sanitizer/wiki/AddressSanitizerForKernel
      [2] https://code.google.com/p/address-sanitizer/wiki/FoundBugs
      [3] https://code.google.com/p/thread-sanitizer/wiki/FoundBugs
      [4] https://code.google.com/p/memory-sanitizer/wiki/FoundBugs
      [5] https://code.google.com/p/address-sanitizer/wiki/AddressSanitizerForKernel#Trophies
      Based on work by Andrey Konovalov.
      Signed-off-by: default avatarAndrey Ryabinin <a.ryabinin@samsung.com>
      Acked-by: default avatarMichal Marek <mmarek@suse.cz>
      Signed-off-by: default avatarAndrey Konovalov <adech.fo@gmail.com>
      Cc: Dmitry Vyukov <dvyukov@google.com>
      Cc: Konstantin Serebryany <kcc@google.com>
      Cc: Dmitry Chernenkov <dmitryc@google.com>
      Cc: Yuri Gribov <tetra2005@gmail.com>
      Cc: Konstantin Khlebnikov <koct9i@gmail.com>
      Cc: Sasha Levin <sasha.levin@oracle.com>
      Cc: Christoph Lameter <cl@linux.com>
      Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
      Cc: Dave Hansen <dave.hansen@intel.com>
      Cc: Andi Kleen <andi@firstfloor.org>
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: "H. Peter Anvin" <hpa@zytor.com>
      Cc: Christoph Lameter <cl@linux.com>
      Cc: Pekka Enberg <penberg@kernel.org>
      Cc: David Rientjes <rientjes@google.com>
      Cc: Stephen Rothwell <sfr@canb.auug.org.au>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
  8. 21 Oct, 2014 1 commit
  9. 19 Aug, 2014 1 commit
    • Masahiro Yamada's avatar
      kbuild: handle multi-objs dependency appropriately · c8589d1e
      Masahiro Yamada authored
      The comment in scripts/Makefile.build says as follows:
        We would rather have a list of rules like
              foo.o: $(foo-objs)
        but that's not so easy, so we rather make all composite objects depend
        on the set of all their parts
      This commit makes it possible!
      For example, assume a Makefile like this
        obj-m = foo.o bar.o
        foo-objs := foo1.o foo2.o
        bar-objs := bar1.o bar2.o
      Without this patch, foo.o depends on all of
      foo1.o foo2.o bar1.o bar2.o.
      It looks funny that foo.o is regenerated when bar1.c is updated.
      Now we can handle the dependency of foo.o and bar.o separately.
      Signed-off-by: default avatarMasahiro Yamada <yamada.m@jp.panasonic.com>
      Signed-off-by: default avatarMichal Marek <mmarek@suse.cz>
  10. 30 Apr, 2014 1 commit
  11. 29 Mar, 2014 1 commit
  12. 20 Feb, 2014 2 commits
    • Jason Cooper's avatar
      kbuild: dtbs_install: new make target · f4d4ffc0
      Jason Cooper authored
      Unlike other build products in the Linux kernel, there is no 'make
      *install' mechanism to put devicetree blobs in a standard place.
      This commit adds a new 'dtbs_install' make target which copies all of
      the dtbs into the INSTALL_DTBS_PATH directory. INSTALL_DTBS_PATH can be
      set before calling make to change the default install directory. If not
      set then it defaults to:
      This is done to keep dtbs from different kernel versions separate until
      things have settled down.  Once the dtbs are stable, and not so strongly
      linked to the kernel version, the devicetree files will most likely move
      to their own repo.  Users will need to upgrade install scripts at that
      v7: (reworked by Grant Likely)
      - Moved rules from arch/arm/Makefile to arch/arm/boot/dts/Makefile so
        that each dtb install could have a separate target and be reported as
        part of the make output.
      - Fixed dependency problem to ensure $KERNELRELEASE is calculated before
        attempting to install
      - Removed option to call external script. Copying the files should be
        sufficient and a build system can post-process the install directory.
        Despite the fact an external script is used for installing the kernel,
        I don't think that is a pattern that should be encouraged. I would
        rather see buildroot type tools post process the install directory to
        rename or move dtb files after installing to a staging directory.
        - Plus it is easy to add a hook after the fact without blocking the
          rest of this feature.
      - Move the helper targets into scripts/Makefile.lib with the rest of the
        common dtb rules
      Signed-off-by: default avatarJason Cooper <jason@lakedaemon.net>
      Signed-off-by: default avatarGrant Likely <grant.likely@linaro.org>
      Cc: Michal Marek <mmarek@suse.cz>
      Cc: Russell King <linux@arm.linux.org.uk>
      Cc: Rob Herring <robh+dt@kernel.org>
    • Grant Likely's avatar
      of: Move testcase FDT data into drivers/of · b5190516
      Grant Likely authored
      The testcase data is usable by any platform. This patch moves it into
      the drivers/of directory so it can be included by any architecture.
      Using the test cases requires manually adding #include <testcases.dtsi>
      to the end of the boards .dtsi file and enabling CONFIG_OF_SELFTEST. Not
      pretty though. A useful project would be to make the testcase code
      easier to execute.
      Signed-off-by: default avatarGrant Likely <grant.likely@linaro.org>
  13. 09 Jul, 2013 1 commit
  14. 03 Jul, 2013 1 commit
    • 张忠山's avatar
      kbuild: create directory for dir/file.o · 4d47dde4
      张忠山 authored
      When add a obj with dir to obj-y, like this
          obj-y += dir/file.o
      The $(obj)/dir not created, this patch fix this.
      When try to add a file(which in a subdir) to my board's obj-y, the build
      progress crashed.
      For example, I use at91rm9200ek board, and in kernel dir run:
        mkdir objtree
        make O=objtree at91rm9200_defconfig
        mkdir arch/arm/mach-at91/dir
        touch arch/arm/mach-at91/dir/file.c
      and edit arch/arm/mach-at91/dir/file.c to add some code.
      then edit arch/arm/mach-at91/Makefile, change the following line:
        obj-$(CONFIG_MACH_AT91RM9200EK) += board-rm9200ek.o
        obj-$(CONFIG_MACH_AT91RM9200EK) += board-rm9200ek.o dir/file.o
      Now build it:
        make O=objtree
      Then the error appears:
        CC      arch/arm/mach-at91/board-rm9200dk.o
        CC      arch/arm/mach-at91/board-rm9200ek.o
        CC      arch/arm/mach-at91/dir/file.o
          fatal error: opening dependency file
          arch/arm/mach-at91/dir/.file.o.d: No such file or directory
      Check the objtree:
        LANG=en ls objtree/arch/arm/mach-at91/dir
        ls: cannot access objtree/arch/arm/mach-at91/dir: No such file or directory
      It's apparently that the target dir not created for file.o
      Check kbuild source code. It seems that kbuild create dirs for that in
      $(obj-dirs).  But if the dir need not to create a built-in.o, It should
      never in  $(obj-dirs).
      So I make this patch to make sure It in  $(obj-dirs)
      this bug caused by commit
         f5fb9765Signed-off-by: default avatar张忠山 <zzs0213@gmail.com>
      Signed-off-by: default avatarMichal Marek <mmarek@suse.cz>
  15. 13 Jun, 2013 2 commits
  16. 23 May, 2013 1 commit
    • Matthijs Kooijman's avatar
      kbuild: Don't assume dts files live in arch/*/boot/dts · ad061568
      Matthijs Kooijman authored
      In commit b40b25ff (kbuild: always run gcc -E on *.dts, remove cmd_dtc_cpp),
      dts building was changed to always use the C preprocessor. This meant
      that the .dts file passed to dtc is not the original, but the
      preprocessed one.
      When compiling with a separate build directory (i.e., with O=), this
      preprocessed file will not live in the same directory as the original.
      When the .dts file includes .dtsi files, dtc will look for them in the
      build directory, not in the source directory and compilation will fail.
      The commit referenced above tried to fix this by passing arch/*/boot/dts
      as an include path to dtc. However, for mips, the .dts files are not in
      this directory, so dts compilation on mips breaks for some targets.
      Instead of hardcoding this particular include path, this commit just
      uses the directory of the .dts file that is being compiled, which
      effectively restores the previous behaviour wrt includes. For most .dts
      files, this path is just the same as the previous hardcoded
      arch/*/boot/dts path.
      This was tested on a mips (rt3052) and an arm (bcm2835) target.
      Signed-off-by: default avatarMatthijs Kooijman <matthijs@stdin.nl>
      Reviewed-by: default avatarStephen Warren <swarren@nvidia.com>
      Signed-off-by: default avatarMichal Marek <mmarek@suse.cz>
  17. 05 Apr, 2013 3 commits
    • Stephen Warren's avatar
      kbuild: always run gcc -E on *.dts, remove cmd_dtc_cpp · b40b25ff
      Stephen Warren authored
      Replace cmd_dtc with cmd_dtc_cpp, and delete the latter.
      Previously, a special file extension (.dtsp) was required to trigger
      the C pre-processor to run on device tree files. This was ugly. Now that
      previous changes have enhanced cmd_dtc_cpp to collect dependency
      information from both gcc -E and dtc, we can transparently run the pre-
      processor on all device tree files, irrespective of whether they
      use /include/ or #include syntax to include *.dtsi.
      Signed-off-by: default avatarStephen Warren <swarren@nvidia.com>
      Acked-by: default avatarRob Herring <rob.herring@calxeda.com>
    • Stephen Warren's avatar
      kbuild: cmd_dtc_cpp: extract deps from both gcc -E and dtc · 85f02be8
      Stephen Warren authored
      Prior to this change, when compiling *.dts to *.dtb, the dependency
      output from dtc would be used, and when compiling *.dtsp to *.dtb, the
      dependency output from gcc -E alone would be used, despite dtc also
      being invoked (on a temporary file that was guaranteed to have no
      With this change, when compiling *.dtsp to *.dtb, the dependency files
      from both gcc -E and dtc are used. This will allow cmd_dtc_cpp to
      replace cmd_dtc in a future change. In turn, that will allow the C pre-
      processor to be run transparently on *.dts, without the need to a
      separate rule or file extension to trigger it.
      Signed-off-by: default avatarStephen Warren <swarren@nvidia.com>
      Acked-by: default avatarRob Herring <rob.herring@calxeda.com>
    • Stephen Warren's avatar
      kbuild: create an "include chroot" for DT bindings · c58299aa
      Stephen Warren authored
      The recent dtc+cpp support allows header files and C pre-processor
      defines/macros to be used when compiling device tree files. These
      headers will typically define various constants that are part of the
      device tree bindings.
      The original patch which set up the dtc+cpp include path only considered
      using those headers from device tree files. However, most are also
      useful for kernel code which needs to interpret the device tree.
      In both the DT files and the kernel, I'd like to include the DT-related
      headers in the same way, for example, <dt-bindings/gpio/tegra-gpio.h>.
      That will simplify any text which discusses the DT header locations.
      Creating a <dt-bindings/> for kernel source to use is as simple as
      placing files into include/dt-bindings/.
      However, when compiling DT files, the include path should be restricted
      so that only the dt-bindings path is available; arbitrary kernel headers
      shouldn't be exposed. For this reason, create a specific include
      directory for use by dtc+cpp, and symlink dt-bindings from there to the
      actual location of include/dt-bindings/. For want of a better location,
      place this "include chroot" into the existing dts/ directory.
      arch/*/boot/dts/include/dt-bindings -> ../../../../../include/dt-bindings
      Some headers used by device tree files may not be useful to the kernel;
      they may be used simply to aid in constructing the DT file (e.g. macros
      to create a node), but not define any information that the kernel needs
      to share. These may be placed directly into arch/*/boot/dts/ along with
      the DT files themselves.
      Acked-by: default avatarMichal Marek <mmarek@suse.cz>
      Acked-by: default avatarShawn Guo <shawn.guo@linaro.org>
      Acked-by: default avatarRob Herring <rob.herring@calxeda.com>
      Signed-off-by: default avatarStephen Warren <swarren@nvidia.com>
  18. 14 Mar, 2013 1 commit
    • Rusty Russell's avatar
      CONFIG_SYMBOL_PREFIX: cleanup. · b92021b0
      Rusty Russell authored
      We have CONFIG_SYMBOL_PREFIX, which three archs define to the string
      "_".  But Al Viro broke this in "consolidate cond_syscall and
      SYSCALL_ALIAS declarations" (in linux-next), and he's not the first to
      do so.
      Using CONFIG_SYMBOL_PREFIX is awkward, since we usually just want to
      prefix it so something.  So various places define helpers which are
      defined to nothing if CONFIG_SYMBOL_PREFIX isn't set:
      1) include/asm-generic/unistd.h defines __SYMBOL_PREFIX.
      2) include/asm-generic/vmlinux.lds.h defines VMLINUX_SYMBOL(sym)
      3) include/linux/export.h defines MODULE_SYMBOL_PREFIX.
      4) include/linux/kernel.h defines SYMBOL_PREFIX (which differs from #7)
      5) kernel/modsign_certificate.S defines ASM_SYMBOL(sym)
      6) scripts/modpost.c defines MODULE_SYMBOL_PREFIX
      7) scripts/Makefile.lib defines SYMBOL_PREFIX on the commandline if
         CONFIG_SYMBOL_PREFIX is set, so that we have a non-string version
         for pasting.
      (arch/h8300/include/asm/linkage.h defines SYMBOL_NAME(), too).
      Let's solve this properly:
      1) No more generic prefix, just CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX.
      2) Make linux/export.h usable from asm.
      4) Make everyone use them.
      Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
      Reviewed-by: default avatarJames Hogan <james.hogan@imgtec.com>
      Tested-by: James Hogan <james.hogan@imgtec.com> (metag)
  19. 13 Feb, 2013 1 commit
    • Stephen Warren's avatar
      kbuild: limit dtc+cpp include path · e570d7c1
      Stephen Warren authored
      Device tree source files may now include header files. The intent is
      that those header files define/name constants used as part of the DT
      bindings. Currently this feature is open to abuse, since any kernel
      header file at all can be included, This could allow device tree files
      to become dependant on kernel headers files, and thus make them no
      longer OS-independent. This would also prevent separating the device
      tree source files from the kernel repository.
      Solve this by limiting the cpp include path for device tree files to
      separate directories.
      Signed-off-by: default avatarStephen Warren <swarren@nvidia.com>
      Signed-off-by: default avatarGrant Likely <grant.likely@secretlab.ca>
  20. 08 Feb, 2013 1 commit
  21. 30 Nov, 2012 1 commit
    • Stephen Warren's avatar
      kbuild: centralize .dts->.dtb rule · 90b335fb
      Stephen Warren authored
      All architectures that use cmd_dtc do so in almost the same way. Create
      a central build rule to avoid duplication. The one difference is that
      most current uses of dtc build $(obj)/%.dtb from $(src)/dts/%.dts rather
      than building the .dtb in the same directory as the .dts file. This
      difference will be eliminated arch-by-arch in future patches.
      MIPS is the exception here; it already uses the exact same rule as the
      new common rule, so the duplicate is removed in this patch to avoid any
      conflict. arch/mips changes courtesy of Ralf Baechle.
      Update Documentation/kbuild to remove the explicit call to cmd_dtc from
      the example, now that the rule exists in a centralized location.
      Cc: Arnd Bergmann <arnd@arndb.de>
      Cc: linux-arm-kernel@lists.infradead.org
      Cc: Olof Johansson <olof@lixom.net>
      Cc: Russell King <linux@arm.linux.org.uk>
      Acked-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
      Cc: Jonas Bonn <jonas@southpole.se>
      Cc: linux@lists.openrisc.net
      Cc: Aurelien Jacquiot <a-jacquiot@ti.com>
      Cc: linux-c6x-dev@linux-c6x.org
      Cc: Mark Salter <msalter@redhat.com>
      Cc: Michal Simek <monstr@monstr.eu>
      Cc: microblaze-uclinux@itee.uq.edu.au
      Cc: Chris Zankel <chris@zankel.net>
      Cc: linux-xtensa@linux-xtensa.org
      Cc: Max Filippov <jcmvbkbc@gmail.com>
      Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
      Signed-off-by: default avatarStephen Warren <swarren@nvidia.com>
      Signed-off-by: default avatarRob Herring <rob.herring@calxeda.com>
  22. 26 Mar, 2012 1 commit
  23. 14 Jan, 2012 1 commit
    • Stephen Warren's avatar
      Kbuild: Use dtc's -d (dependency) option · 7c431851
      Stephen Warren authored
      This hooks dtc into Kbuild's dependency system.
      Thus, for example, "make dtbs" will rebuild tegra-harmony.dtb if only
      tegra20.dtsi has changed yet tegra-harmony.dts has not. The previous
      lack of this feature recently caused me to have very confusing "git
      bisect" results.
      For ARM, it's obvious what to add to $(targets). I'm not familiar enough
      with other architectures to know what to add there. Powerpc appears to
      already add various .dtb files into $(targets), but the other archs may
      need something added to $(targets) to work.
      Signed-off-by: default avatarStephen Warren <swarren@nvidia.com>
      Acked-by: default avatarShawn Guo <shawn.guo@linaro.org>
      [mmarek: Dropped arch/c6x part to avoid merging commits from the middle
      of the merge window]
      Signed-off-by: default avatarMichal Marek <mmarek@suse.cz>
  24. 08 Jan, 2012 1 commit
    • Michal Marek's avatar
      kbuild: Fix comment in Makefile.lib · 5bb0571b
      Michal Marek authored
      KBUILD_MODNAME is not defined for files that are linked into multiple
      modules, and trying to change reality to match documentation would
      result in all sorts of trouble. E.g. options for built-in modules would
      be called either foo_bar.param, foo.param, or bar.param, depending on
      the configuration. So just change the comment.
      Signed-off-by: default avatarMichal Marek <mmarek@suse.cz>
  25. 31 Aug, 2011 1 commit
  26. 09 Jun, 2011 2 commits
  27. 18 Apr, 2011 1 commit
  28. 13 Jan, 2011 1 commit
    • Lasse Collin's avatar
      decompressors: add XZ decompressor module · 24fa0402
      Lasse Collin authored
      In userspace, the .lzma format has become mostly a legacy file format that
      got superseded by the .xz format.  Similarly, LZMA Utils was superseded by
      XZ Utils.
      These patches add support for XZ decompression into the kernel.  Most of
      the code is as is from XZ Embedded <http://tukaani.org/xz/embedded.html>.
      It was written for the Linux kernel but is usable in other projects too.
      Advantages of XZ over the current LZMA code in the kernel:
        - Nice API that can be used by other kernel modules; it's
          not limited to kernel, initramfs, and initrd decompression.
        - Integrity check support (CRC32)
        - BCJ filters improve compression of executable code on
          certain architectures. These together with LZMA2 can
          produce a few percent smaller kernel or Squashfs images
          than plain LZMA without making the decompression slower.
      This patch: Add the main decompression code (xz_dec), testing module
      (xz_dec_test), wrapper script (xz_wrap.sh) for the xz command line tool,
      and documentation.  The xz_dec module is enough to have a usable XZ
      decompressor e.g.  for Squashfs.
      Signed-off-by: default avatarLasse Collin <lasse.collin@tukaani.org>
      Cc: "H. Peter Anvin" <hpa@zytor.com>
      Cc: Alain Knaff <alain@knaff.lu>
      Cc: Albin Tonnerre <albin.tonnerre@free-electrons.com>
      Cc: Phillip Lougher <phillip@lougher.demon.co.uk>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
  29. 23 Dec, 2010 1 commit
    • Dirk Brandewie's avatar
      of: Add support for linking device tree blobs into vmlinux · aab94339
      Dirk Brandewie authored
      This patch adds support for linking device tree blob(s) into
      vmlinux. Modifies asm-generic/vmlinux.lds.h to add linking
      .dtb sections into vmlinux. To maintain compatiblity with the of/fdt
      driver code platforms MUST copy the blob to a non-init memory location
      before the kernel frees the .init.* sections in the image.
      Modifies scripts/Makefile.lib to add a kbuild command to
      compile DTS files to device tree blobs and a rule to create objects to
      wrap the blobs for linking.
      STRUCT_ALIGNMENT is defined in vmlinux.lds.h for use in the rule to
      create wrapper objects for the dtb in Makefile.lib.  The
      STRUCT_ALIGN() macro in vmlinux.lds.h is modified to use the
      STRUCT_ALIGNMENT definition.
      The DTB's are placed on 32 byte boundries to allow parsing the blob
      with driver/of/fdt.c during early boot without having to copy the blob
      to get the structure alignment GCC expects.
      A DTB is linked in by adding the DTB object to the list of objects to
      be linked into vmlinux in the archtecture specific Makefile using
         obj-y += foo.dtb.o
      Signed-off-by: default avatarDirk Brandewie <dirk.brandewie@gmail.com>
      Acked-by: default avatarMichal Marek <mmarek@suse.cz>
      [grant.likely@secretlab.ca: cleaned up whitespace inconsistencies]
      Signed-off-by: default avatarGrant Likely <grant.likely@secretlab.ca>
  30. 28 Oct, 2010 1 commit
  31. 22 Sep, 2010 1 commit
  32. 06 Apr, 2010 1 commit
    • Borislav Petkov's avatar
      x86: Add optimized popcnt variants · d61931d8
      Borislav Petkov authored
      Add support for the hardware version of the Hamming weight function,
      popcnt, present in CPUs which advertize it under CPUID, Function
      0x0000_0001_ECX[23]. On CPUs which don't support it, we fallback to the
      default lib/hweight.c sw versions.
      A synthetic benchmark comparing popcnt with __sw_hweight64 showed almost
      a 3x speedup on a F10h machine.
      Signed-off-by: default avatarBorislav Petkov <borislav.petkov@amd.com>
      LKML-Reference: <20100318112015.GC11152@aftab>
      Signed-off-by: default avatarH. Peter Anvin <hpa@zytor.com>
  33. 11 Mar, 2010 1 commit
  34. 13 Jan, 2010 1 commit
    • Jonathan Nieder's avatar
      kbuild: really fix bzImage build with non-bash sh · 1373411a
      Jonathan Nieder authored
      In an x86 build with CONFIG_KERNEL_LZMA enabled and dash as sh,
      arch/x86/boot/compressed/vmlinux.bin.lzma ends with
      '\xf0\x7d\x39\x00' (16 bytes) instead of the 4 bytes intended and
      the resulting vmlinuz fails to boot.  This improves on the
      previous behavior, in which the file contained the characters
      '-ne ' as well, but not by much.
      Previous commits replaced "echo -ne" first with "/bin/echo -ne",
      then "printf" in the hope of improving portability, but none of
      these commands is guaranteed to support hexadecimal escapes on
      POSIX systems.  So use the shell to convert from hexadecimal to
      With this change, an LZMA-compressed kernel built with dash as sh
      boots correctly again.
      Reported-by: default avatarSebastian Dalfuß <sd@sedf.de>
      Reported-by: default avatarOliver Hartkopp <oliver@hartkopp.net>
      Reported-by: default avatarMichael Guntsche <mike@it-loops.com>
      Signed-off-by: default avatarJonathan Nieder <jrnieder@gmail.com>
      Cc: Michael Tokarev <mjt@tls.msk.ru>
      Cc: Alek Du <alek.du@intel.com>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarMichal Marek <mmarek@suse.cz>
  35. 11 Jan, 2010 1 commit
    • Albin Tonnerre's avatar
      lib: add support for LZO-compressed kernels · 7dd65feb
      Albin Tonnerre authored
      This patch series adds generic support for creating and extracting
      LZO-compressed kernel images, as well as support for using such images on
      the x86 and ARM architectures, and support for creating and using
      LZO-compressed initrd and initramfs images.
      Russell King said:
      : Testing on a Cortex A9 model:
      : - lzo decompressor is 65% of the time gzip takes to decompress a kernel
      : - lzo kernel is 9% larger than a gzip kernel
      : which I'm happy to say confirms your figures when comparing the two.
      : However, when comparing your new gzip code to the old gzip code:
      : - new is 99% of the size of the old code
      : - new takes 42% of the time to decompress than the old code
      : What this means is that for a proper comparison, the results get even better:
      : - lzo is 7.5% larger than the old gzip'd kernel image
      : - lzo takes 28% of the time that the old gzip code took
      : So the expense seems definitely worth the effort.  The only reason I
      : can think of ever using gzip would be if you needed the additional
      : compression (eg, because you have limited flash to store the image.)
      : I would argue that the default for ARM should therefore be LZO.
      This patch:
      The lzo compressor is worse than gzip at compression, but faster at
      extraction.  Here are some figures for an ARM board I'm working on:
      Uncompressed size: 3.24Mo
      gzip  1.61Mo 0.72s
      lzo   1.75Mo 0.48s
      So for a compression ratio that is still relatively close to gzip, it's
      much faster to extract, at least in that case.
      This part contains:
       - Makefile routine to support lzo compression
       - Fixes to the existing lzo compressor so that it can be used in
         compressed kernels
       - wrapper around the existing lzo1x_decompress, as it only extracts one
         block at a time, while we need to extract a whole file here
       - config dialog for kernel compression
      [akpm@linux-foundation.org: coding-style fixes]
      [akpm@linux-foundation.org: cleanup]
      Signed-off-by: default avatarAlbin Tonnerre <albin.tonnerre@free-electrons.com>
      Tested-by: default avatarWu Zhangjin <wuzhangjin@gmail.com>
      Acked-by: default avatar"H. Peter Anvin" <hpa@zytor.com>
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Tested-by: default avatarRussell King <rmk@arm.linux.org.uk>
      Acked-by: default avatarRussell King <rmk@arm.linux.org.uk>
      Cc: Ralf Baechle <ralf@linux-mips.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>