• Thomas Gleixner's avatar
    cpufreq/sparc-us2e: Replace racy task affinity logic · 12699ac5
    Thomas Gleixner authored
    The access to the HBIRD_ESTAR_MODE register in the cpu frequency control
    functions must happen on the target CPU. This is achieved by temporarily
    setting the affinity of the calling user space thread to the requested CPU
    and reset it to the original affinity afterwards.
    
    That's racy vs. CPU hotplug and concurrent affinity settings for that
    thread resulting in code executing on the wrong CPU and overwriting the
    new affinity setting.
    
    Replace it by a straight forward smp function call. 
    Signed-off-by: 's avatarThomas Gleixner <tglx@linutronix.de>
    Acked-by: 's avatarViresh Kumar <viresh.kumar@linaro.org>
    Cc: Fenghua Yu <fenghua.yu@intel.com>
    Cc: Tony Luck <tony.luck@intel.com>
    Cc: Herbert Xu <herbert@gondor.apana.org.au>
    Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
    Cc: Sebastian Siewior <bigeasy@linutronix.de>
    Cc: linux-pm@vger.kernel.org
    Cc: Lai Jiangshan <jiangshanlai@gmail.com>
    Cc: Michael Ellerman <mpe@ellerman.id.au>
    Cc: Tejun Heo <tj@kernel.org>
    Cc: "David S. Miller" <davem@davemloft.net>
    Cc: Len Brown <lenb@kernel.org>
    Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1704131020280.2408@nanosSigned-off-by: 's avatarThomas Gleixner <tglx@linutronix.de>
    12699ac5