target/linux/generic/pending-4.4/091-MIPS-c-r4k-Exclude-sibling-CPUs-in-SMP-calls.patch

   1 From: James Hogan <james.hogan@imgtec.com>
   2 Date: Thu, 3 Mar 2016 21:30:42 +0000
   3 Subject: [PATCH] MIPS: c-r4k: Exclude sibling CPUs in SMP calls
   4
   5 When performing SMP calls to foreign cores, exclude sibling CPUs from
   6 the provided map, as we already handle the local core on the current
   7 CPU. This prevents an IPI call from for example core 0, VPE 1 to VPE 0
   8 on the same core.
   9
  10 Signed-off-by: James Hogan <james.hogan@imgtec.com>
  11 Cc: Ralf Baechle <ralf@linux-mips.org>
  12 Cc: Paul Burton <paul.burton@imgtec.com>
  13 Cc: linux-mips@linux-mips.org
  14 ---
  15
  16 --- a/arch/mips/mm/c-r4k.c
  17 +++ b/arch/mips/mm/c-r4k.c
  18 @@ -96,8 +96,17 @@ static inline void r4k_on_each_cpu(unsig
  19                                    void (*func) (void *info), void *info)
  20  {
  21         preempt_disable();
  22 -       if (r4k_op_needs_ipi(type))
  23 -               smp_call_function_many(&cpu_foreign_map, func, info, 1);
  24 +       /* cpu_foreign_map and cpu_sibling_map[] undeclared when !CONFIG_SMP */
  25 +#ifdef CONFIG_SMP
  26 +       if (r4k_op_needs_ipi(type)) {
  27 +               struct cpumask mask;
  28 +
  29 +               /* exclude sibling CPUs */
  30 +               cpumask_andnot(&mask, &cpu_foreign_map,
  31 +                              &cpu_sibling_map[smp_processor_id()]);
  32 +               smp_call_function_many(&mask, func, info, 1);
  33 +       }
  34 +#endif
  35         func(info);
  36         preempt_enable();
  37  }