[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;