Eric Lee / smarc-fsl-linux-kernel

02 Jun, 2016

22 commits

01 Jun, 2016

1 commit

30 May, 2016

4 commits

29 May, 2016

13 commits

  • e0ab7af9b   hash_string: Fix zero-length case for !DCACHE_WORD_ACCESS ... Browse Code »

    The self-test was updated to cover zero-length strings; the function
    needs to be updated, too.

    Reported-by: Geert Uytterhoeven
    Signed-off-by: George Spelvin
    Fixes: fcfd2fbf22d2 ("fs/namei.c: Add hashlen_string() function")
    Signed-off-by: Linus Torvalds

    George Spelvin
     
  • f2a031b66   Rename other copy of hash_string to hashlen_string ... Browse Code »

    The original name was simply hash_string(), but that conflicted with a
    function with that name in drivers/base/power/trace.c, and I decided
    that calling it "hashlen_" was better anyway.

    But you have to do it in two places.

    [ This caused build errors for architectures that don't define
    CONFIG_DCACHE_WORD_ACCESS - Linus ]

    Signed-off-by: George Spelvin
    Reported-by: Guenter Roeck
    Fixes: fcfd2fbf22d2 ("fs/namei.c: Add hashlen_string() function")
    Signed-off-by: Linus Torvalds

    George Spelvin
     
  • 037369b87   hpfs: implement the show_options method ... Browse Code »

    The HPFS filesystem used generic_show_options to produce string that is
    displayed in /proc/mounts. However, there is a problem that the options
    may disappear after remount. If we mount the filesystem with option1
    and then remount it with option2, /proc/mounts should show both option1
    and option2, however it only shows option2 because the whole option
    string is replaced with replace_mount_options in hpfs_remount_fs.

    To fix this bug, implement the hpfs_show_options function that prints
    options that are currently selected.

    Signed-off-by: Mikulas Patocka
    Cc: stable@vger.kernel.org
    Signed-off-by: Linus Torvalds

    Mikulas Patocka
     
  • 01d6e0871   affs: fix remount failure when there are no options changed ... Browse Code »

    Commit c8f33d0bec99 ("affs: kstrdup() memory handling") checks if the
    kstrdup function returns NULL due to out-of-memory condition.

    However, if we are remounting a filesystem with no change to
    filesystem-specific options, the parameter data is NULL. In this case,
    kstrdup returns NULL (because it was passed NULL parameter), although no
    out of memory condition exists. The mount syscall then fails with
    ENOMEM.

    This patch fixes the bug. We fail with ENOMEM only if data is non-NULL.

    The patch also changes the call to replace_mount_options - if we didn't
    pass any filesystem-specific options, we don't call
    replace_mount_options (thus we don't erase existing reported options).

    Fixes: c8f33d0bec99 ("affs: kstrdup() memory handling")
    Signed-off-by: Mikulas Patocka
    Cc: stable@vger.kernel.org # v4.1+
    Signed-off-by: Linus Torvalds

    Mikulas Patocka
     
  • 44d51706b   hpfs: fix remount failure when there are no options changed ... Browse Code »

    Commit ce657611baf9 ("hpfs: kstrdup() out of memory handling") checks if
    the kstrdup function returns NULL due to out-of-memory condition.

    However, if we are remounting a filesystem with no change to
    filesystem-specific options, the parameter data is NULL. In this case,
    kstrdup returns NULL (because it was passed NULL parameter), although no
    out of memory condition exists. The mount syscall then fails with
    ENOMEM.

    This patch fixes the bug. We fail with ENOMEM only if data is non-NULL.

    The patch also changes the call to replace_mount_options - if we didn't
    pass any filesystem-specific options, we don't call
    replace_mount_options (thus we don't erase existing reported options).

    Fixes: ce657611baf9 ("hpfs: kstrdup() out of memory handling")
    Signed-off-by: Mikulas Patocka
    Cc: stable@vger.kernel.org
    Signed-off-by: Linus Torvalds

    Mikulas Patocka
     
  • 4029632c3   Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus ... Browse Code »

    Pull more MIPS updates from Ralf Baechle:
    "This is the secondnd batch of MIPS patches for 4.7. Summary:

    CPS:
    - Copy EVA configuration when starting secondary VPs.

    EIC:
    - Clear Status IPL.

    Lasat:
    - Fix a few off by one bugs.

    lib:
    - Mark intrinsics notrace. Not only are the intrinsics
    uninteresting, it would cause infinite recursion.

    MAINTAINERS:
    - Add file patterns for MIPS BRCM device tree bindings.
    - Add file patterns for mips device tree bindings.

    MT7628:
    - Fix MT7628 pinmux typos.
    - wled_an pinmux gpio.
    - EPHY LEDs pinmux support.

    Pistachio:
    - Enable KASLR

    VDSO:
    - Build microMIPS VDSO for microMIPS kernels.
    - Fix aliasing warning by building with `-fno-strict-aliasing' for
    debugging but also tracing them might result in recursion.

    Misc:
    - Add missing FROZEN hotplug notifier transitions.
    - Fix clk binding example for varioius PIC32 devices.
    - Fix cpu interrupt controller node-names in the DT files.
    - Fix XPA CPU feature separation.
    - Fix write_gc0_* macros when writing zero.
    - Add inline asm encoding helpers.
    - Add missing VZ accessor microMIPS encodings.
    - Fix little endian microMIPS MSA encodings.
    - Add 64-bit HTW fields and fix its configuration.
    - Fix sigreturn via VDSO on microMIPS kernel.
    - Lots of typo fixes.
    - Add definitions of SegCtl registers and use them"

    * 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus: (49 commits)
    MIPS: Add missing FROZEN hotplug notifier transitions
    MIPS: Build microMIPS VDSO for microMIPS kernels
    MIPS: Fix sigreturn via VDSO on microMIPS kernel
    MIPS: devicetree: fix cpu interrupt controller node-names
    MIPS: VDSO: Build with `-fno-strict-aliasing'
    MIPS: Pistachio: Enable KASLR
    MIPS: lib: Mark intrinsics notrace
    MIPS: Fix 64-bit HTW configuration
    MIPS: Add 64-bit HTW fields
    MAINTAINERS: Add file patterns for mips device tree bindings
    MAINTAINERS: Add file patterns for mips brcm device tree bindings
    MIPS: Simplify DSP instruction encoding macros
    MIPS: Add missing tlbinvf/XPA microMIPS encodings
    MIPS: Fix little endian microMIPS MSA encodings
    MIPS: Add missing VZ accessor microMIPS encodings
    MIPS: Add inline asm encoding helpers
    MIPS: Spelling fix lets -> let's
    MIPS: VR41xx: Fix typo
    MIPS: oprofile: Fix typo
    MIPS: math-emu: Fix typo
    ...

    Linus Torvalds
     
  • d66492bce   fs: fix binfmt_aout.c build error ... Browse Code »

    Various builds (such as i386:allmodconfig) fail with

    fs/binfmt_aout.c:133:2: error: expected identifier or '(' before 'return'
    fs/binfmt_aout.c:134:1: error: expected identifier or '(' before '}' token

    [ Oops. My bad, I had stupidly thought that "allmodconfig" covered this
    on x86-64 too, but it obviously doesn't. Egg on my face. - Linus ]

    Fixes: 5d22fc25d4fc ("mm: remove more IS_ERR_VALUE abuses")
    Signed-off-by: Guenter Roeck
    Signed-off-by: Linus Torvalds

    Guenter Roeck
     
  • 7e0fb73c5   Merge branch 'hash' of git://ftp.sciencehorizons.net/linux ... Browse Code »

    Pull string hash improvements from George Spelvin:
    "This series does several related things:

    - Makes the dcache hash (fs/namei.c) useful for general kernel use.

    (Thanks to Bruce for noticing the zero-length corner case)

    - Converts the string hashes in to use the
    above.

    - Avoids 64-bit multiplies in hash_64() on 32-bit platforms. Two
    32-bit multiplies will do well enough.

    - Rids the world of the bad hash multipliers in hash_32.

    This finishes the job started in commit 689de1d6ca95 ("Minimal
    fix-up of bad hashing behavior of hash_64()")

    The vast majority of Linux architectures have hardware support for
    32x32-bit multiply and so derive no benefit from "simplified"
    multipliers.

    The few processors that do not (68000, h8/300 and some models of
    Microblaze) have arch-specific implementations added. Those
    patches are last in the series.

    - Overhauls the dcache hash mixing.

    The patch in commit 0fed3ac866ea ("namei: Improve hash mixing if
    CONFIG_DCACHE_WORD_ACCESS") was an off-the-cuff suggestion.
    Replaced with a much more careful design that's simultaneously
    faster and better. (My own invention, as there was noting suitable
    in the literature I could find. Comments welcome!)

    - Modify the hash_name() loop to skip the initial HASH_MIX(). This
    would let us salt the hash if we ever wanted to.

    - Sort out partial_name_hash().

    The hash function is declared as using a long state, even though
    it's truncated to 32 bits at the end and the extra internal state
    contributes nothing to the result. And some callers do odd things:

    - fs/hfs/string.c only allocates 32 bits of state
    - fs/hfsplus/unicode.c uses it to hash 16-bit unicode symbols not bytes

    - Modify bytemask_from_count to handle inputs of 1..sizeof(long)
    rather than 0..sizeof(long)-1. This would simplify users other
    than full_name_hash"

    Special thanks to Bruce Fields for testing and finding bugs in v1. (I
    learned some humbling lessons about "obviously correct" code.)

    On the arch-specific front, the m68k assembly has been tested in a
    standalone test harness, I've been in contact with the Microblaze
    maintainers who mostly don't care, as the hardware multiplier is never
    omitted in real-world applications, and I haven't heard anything from
    the H8/300 world"

    * 'hash' of git://ftp.sciencehorizons.net/linux:
    h8300: Add
    microblaze: Add
    m68k: Add
    : Add support for architecture-specific functions
    fs/namei.c: Improve dcache hash function
    Eliminate bad hash multipliers from hash_32() and hash_64()
    Change hash_64() return value to 32 bits
    : Define hash_str() in terms of hashlen_string()
    fs/namei.c: Add hashlen_string() function
    Pull out string hash to

    Linus Torvalds
     
  • 4684fe953   h8300: Add <asm/hash.h> ... Browse Code »

    This will improve the performance of hash_32() and hash_64(), but due
    to complete lack of multi-bit shift instructions on H8, performance will
    still be bad in surrounding code.

    Designing H8-specific hash algorithms to work around that is a separate
    project. (But if the maintainers would like to get in touch...)

    Signed-off-by: George Spelvin
    Cc: Yoshinori Sato
    Cc: uclinux-h8-devel@lists.sourceforge.jp

    George Spelvin
     
  • 7b13277b6   microblaze: Add <asm/hash.h> ... Browse Code »

    Microblaze is an FPGA soft core that can be configured various ways.

    If it is configured without a multiplier, the standard __hash_32()
    will require a call to __mulsi3, which is a slow software loop.

    Instead, use a shift-and-add sequence for the constant multiply.
    GCC knows how to do this, but it's not as clever as some.

    Signed-off-by: George Spelvin
    Cc: Alistair Francis
    Cc: Michal Simek

    George Spelvin
     
  • 14c44b95b   m68k: Add <asm/hash.h> ... Browse Code »

    This provides a multiply by constant GOLDEN_RATIO_32 = 0x61C88647
    for the original mc68000, which lacks a 32x32-bit multiply instruction.

    Yes, the amount of optimization effort put in is excessive. :-)

    Shift-add chain found by Yevgen Voronenko's Hcub algorithm at
    http://spiral.ece.cmu.edu/mcm/gen.html

    Signed-off-by: George Spelvin
    Cc: Geert Uytterhoeven
    Cc: Greg Ungerer
    Cc: Andreas Schwab
    Cc: Philippe De Muyter
    Cc: linux-m68k@lists.linux-m68k.org

    George Spelvin
     
  • 468a94285   <linux/hash.h>: Add support for architecture-specific functions ... Browse Code »

    This is just the infrastructure; there are no users yet.

    This is modelled on CONFIG_ARCH_RANDOM; a CONFIG_ symbol declares
    the existence of .

    That file may define its own versions of various functions, and define
    HAVE_* symbols (no CONFIG_ prefix!) to suppress the generic ones.

    Included is a self-test (in lib/test_hash.c) that verifies the basics.
    It is NOT in general required that the arch-specific functions compute
    the same thing as the generic, but if a HAVE_* symbol is defined with
    the value 1, then equality is tested.

    Signed-off-by: George Spelvin
    Cc: Geert Uytterhoeven
    Cc: Greg Ungerer
    Cc: Andreas Schwab
    Cc: Philippe De Muyter
    Cc: linux-m68k@lists.linux-m68k.org
    Cc: Alistair Francis
    Cc: Michal Simek
    Cc: Yoshinori Sato
    Cc: uclinux-h8-devel@lists.sourceforge.jp

    George Spelvin
     
  • 2a18da7a9   fs/namei.c: Improve dcache hash function ... Browse Code »

    Patch 0fed3ac866 improved the hash mixing, but the function is slower
    than necessary; there's a 7-instruction dependency chain (10 on x86)
    each loop iteration.

    Word-at-a-time access is a very tight loop (which is good, because
    link_path_walk() is one of the hottest code paths in the entire kernel),
    and the hash mixing function must not have a longer latency to avoid
    slowing it down.

    There do not appear to be any published fast hash functions that:
    1) Operate on the input a word at a time, and
    2) Don't need to know the length of the input beforehand, and
    3) Have a single iterated mixing function, not needing conditional
    branches or unrolling to distinguish different loop iterations.

    One of the algorithms which comes closest is Yann Collet's xxHash, but
    that's two dependent multiplies per word, which is too much.

    The key insights in this design are:

    1) Barring expensive ops like multiplies, to diffuse one input bit
    across 64 bits of hash state takes at least log2(64) = 6 sequentially
    dependent instructions. That is more cycles than we'd like.
    2) An operation like "hash ^= hash << 13" requires a second temporary
    register anyway, and on a 2-operand machine like x86, it's three
    instructions.
    3) A better use of a second register is to hold a two-word hash state.
    With careful design, no temporaries are needed at all, so it doesn't
    increase register pressure. And this gets rid of register copying
    on 2-operand machines, so the code is smaller and faster.
    4) Using two words of state weakens the requirement for one-round mixing;
    we now have two rounds of mixing before cancellation is possible.
    5) A two-word hash state also allows operations on both halves to be
    done in parallel, so on a superscalar processor we get more mixing
    in fewer cycles.

    I ended up using a mixing function inspired by the ChaCha and Speck
    round functions. It is 6 simple instructions and 3 cycles per iteration
    (assuming multiply by 9 can be done by an "lea" instruction):

    x ^= *input++;
    y ^= x; x = ROL(x, K1);
    x += y; y = ROL(y, K2);
    y *= 9;

    Not only is this reversible, two consecutive rounds are reversible:
    if you are given the initial and final states, but not the intermediate
    state, it is possible to compute both input words. This means that at
    least 3 words of input are required to create a collision.

    (It also has the property, used by hash_name() to avoid a branch, that
    it hashes all-zero to all-zero.)

    The rotate constants K1 and K2 were found by experiment. The search took
    a sample of random initial states (I used 1023) and considered the effect
    of flipping each of the 64 input bits on each of the 128 output bits two
    rounds later. Each of the 8192 pairs can be considered a biased coin, and
    adding up the Shannon entropy of all of them produces a score.

    The best-scoring shifts also did well in other tests (flipping bits in y,
    trying 3 or 4 rounds of mixing, flipping all 64*63/2 pairs of input bits),
    so the choice was made with the additional constraint that the sum of the
    shifts is odd and not too close to the word size.

    The final state is then folded into a 32-bit hash value by a less carefully
    optimized multiply-based scheme. This also has to be fast, as pathname
    components tend to be short (the most common case is one iteration!), but
    there's some room for latency, as there is a fair bit of intervening logic
    before the hash value is used for anything.

    (Performance verified with "bonnie++ -s 0 -n 1536:-2" on tmpfs. I need
    a better benchmark; the numbers seem to show a slight dip in performance
    between 4.6.0 and this patch, but they're too noisy to quote.)

    Special thanks to Bruce fields for diligent testing which uncovered a
    nasty fencepost error in an earlier version of this patch.

    [checkpatch.pl formatting complaints noted and respectfully disagreed with.]

    Signed-off-by: George Spelvin
    Tested-by: J. Bruce Fields

    George Spelvin