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    Subject[GIT PULL for-4.4 02/25] watchdog: kempld: fix gcc-4.3 build
    Date
    From: Arnd Bergmann <arnd@arndb.de>

    [ Upstream commit 3736d4eb6af37492aeded7fec0072dedd959c842 ]

    gcc-4.3 can't decide whether the constant value in
    kempld_prescaler[PRESCALER_21] is built-time constant or
    not, and gets confused by the logic in do_div():

    drivers/watchdog/kempld_wdt.o: In function `kempld_wdt_set_stage_timeout':
    kempld_wdt.c:(.text.kempld_wdt_set_stage_timeout+0x130): undefined reference to `__aeabi_uldivmod'

    This adds a call to ACCESS_ONCE() to force it to not consider
    it to be constant, and leaves the more efficient normal case
    in place for modern compilers, using an #ifdef to annotate
    why we do this hack.

    Signed-off-by: Arnd Bergmann <arnd@arndb.de>
    Signed-off-by: Guenter Roeck <linux@roeck-us.net>
    Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
    ---
    drivers/watchdog/kempld_wdt.c | 9 ++++++++-
    1 file changed, 8 insertions(+), 1 deletion(-)

    diff --git a/drivers/watchdog/kempld_wdt.c b/drivers/watchdog/kempld_wdt.c
    index 5bf931ce1353..978098f71761 100644
    --- a/drivers/watchdog/kempld_wdt.c
    +++ b/drivers/watchdog/kempld_wdt.c
    @@ -140,12 +140,19 @@ static int kempld_wdt_set_stage_timeout(struct kempld_wdt_data *wdt_data,
    unsigned int timeout)
    {
    struct kempld_device_data *pld = wdt_data->pld;
    - u32 prescaler = kempld_prescaler[PRESCALER_21];
    + u32 prescaler;
    u64 stage_timeout64;
    u32 stage_timeout;
    u32 remainder;
    u8 stage_cfg;

    +#if GCC_VERSION < 40400
    + /* work around a bug compiling do_div() */
    + prescaler = READ_ONCE(kempld_prescaler[PRESCALER_21]);
    +#else
    + prescaler = kempld_prescaler[PRESCALER_21];
    +#endif
    +
    if (!stage)
    return -EINVAL;

    --
    2.11.0
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