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    Subject[PATCH RESEND] lib: fix bitmap_parse() on 64-bit big endian archs
    Date
    Commit 2d6261583be0 ("lib: rework bitmap_parse()") does
    not take into account order of halfwords on 64-bit big
    endian architectures.

    Fixes: 2d6261583be0 ("lib: rework bitmap_parse()")
    Cc: stable@vger.kernel.org
    Cc: Yury Norov <yury.norov@gmail.com>
    Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
    Cc: Amritha Nambiar <amritha.nambiar@intel.com>
    Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
    Cc: Chris Wilson <chris@chris-wilson.co.uk>
    Cc: Kees Cook <keescook@chromium.org>
    Cc: Matthew Wilcox <willy@infradead.org>
    Cc: Miklos Szeredi <mszeredi@redhat.com>
    Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
    Cc: Steffen Klassert <steffen.klassert@secunet.com>
    Cc: "Tobin C . Harding" <tobin@kernel.org>
    Cc: Vineet Gupta <vineet.gupta1@synopsys.com>
    Cc: Will Deacon <will.deacon@arm.com>
    Cc: Willem de Bruijn <willemb@google.com>
    Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
    ---
    lib/bitmap.c | 20 ++++++++++++++++++--
    1 file changed, 18 insertions(+), 2 deletions(-)

    diff --git a/lib/bitmap.c b/lib/bitmap.c
    index 89260aa..a725e46 100644
    --- a/lib/bitmap.c
    +++ b/lib/bitmap.c
    @@ -717,6 +717,19 @@ static const char *bitmap_get_x32_reverse(const char *start,
    return end;
    }

    +#if defined(__BIG_ENDIAN) && defined(CONFIG_64BIT)
    +static void save_x32_chunk(unsigned long *maskp, u32 chunk, int chunk_idx)
    +{
    + maskp += (chunk_idx / 2);
    + ((u32 *)maskp)[(chunk_idx & 1) ^ 1] = chunk;
    +}
    +#else
    +static void save_x32_chunk(unsigned long *maskp, u32 chunk, int chunk_idx)
    +{
    + ((u32 *)maskp)[chunk_idx] = chunk;
    +}
    +#endif
    +
    /**
    * bitmap_parse - convert an ASCII hex string into a bitmap.
    * @start: pointer to buffer containing string.
    @@ -738,7 +751,8 @@ int bitmap_parse(const char *start, unsigned int buflen,
    {
    const char *end = strnchrnul(start, buflen, '\n') - 1;
    int chunks = BITS_TO_U32(nmaskbits);
    - u32 *bitmap = (u32 *)maskp;
    + int chunk_idx = 0;
    + u32 chunk;
    int unset_bit;

    while (1) {
    @@ -749,9 +763,11 @@ int bitmap_parse(const char *start, unsigned int buflen,
    if (!chunks--)
    return -EOVERFLOW;

    - end = bitmap_get_x32_reverse(start, end, bitmap++);
    + end = bitmap_get_x32_reverse(start, end, &chunk);
    if (IS_ERR(end))
    return PTR_ERR(end);
    +
    + save_x32_chunk(maskp, chunk, chunk_idx++);
    }

    unset_bit = (BITS_TO_U32(nmaskbits) - chunks) * 32;
    --
    1.8.3.1
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