[MIPS] FPU affinity for MT ASE.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 30 insertions, 0 deletions

diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index 6336fe8008ec..e9902d89dc0a 100644
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -758,6 +758,36 @@ asmlinkage void do_cpu(struct pt_regs *regs)
                                                 &current->thread.fpu.soft);
                         if (sig)
                                 force_sig(sig, current);
+#ifdef CONFIG_MIPS_MT_FPAFF
+                        else {
+                        /*
+                         * MIPS MT processors may have fewer FPU contexts
+                         * than CPU threads. If we've emulated more than
+                         * some threshold number of instructions, force
+                         * migration to a "CPU" that has FP support.
+                         */
+                         if(mt_fpemul_threshold > 0
+                         && ((current->thread.emulated_fp++
+                            > mt_fpemul_threshold))) {
+                          /*
+                           * If there's no FPU present, or if the
+                           * application has already restricted
+                           * the allowed set to exclude any CPUs
+                           * with FPUs, we'll skip the procedure.
+                           */
+                          if (cpus_intersects(current->cpus_allowed,
+                                                mt_fpu_cpumask)) {
+                            cpumask_t tmask;
+
+                            cpus_and(tmask,
+                                        current->thread.user_cpus_allowed,
+                                        mt_fpu_cpumask);
+                            set_cpus_allowed(current, tmask);
+                            current->thread.mflags |= MF_FPUBOUND;
+                          }
+                         }
+                        }
+#endif /* CONFIG_MIPS_MT_FPAFF */
                 }
 
                 return;