[MIPS] SMTC: Fix holes in SMTC and FPU affinity support.

Signed-off-by: Kevin D. Kissell <kevink@paralogos.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/kernel/mips-mt-fpaff.c

@@ -159,7 +159,7 @@ __setup("fpaff=", fpaff_thresh);
 /*
  * FPU Use Factor empirically derived from experiments on 34K
  */
-#define FPUSEFACTOR 333
+#define FPUSEFACTOR 2000
 
 static __init int mt_fp_affinity_init(void)
 {

arch/mips/kernel/process.c

@@ -55,7 +55,7 @@ void __noreturn cpu_idle(void)
 	while (1) {
 		tick_nohz_stop_sched_tick(1);
 		while (!need_resched()) {
-#ifdef CONFIG_SMTC_IDLE_HOOK_DEBUG
+#ifdef CONFIG_MIPS_MT_SMTC
 			extern void smtc_idle_loop_hook(void);
 
 			smtc_idle_loop_hook();
@@ -145,19 +145,18 @@ int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
 	 */
 	p->thread.cp0_status = read_c0_status() & ~(ST0_CU2|ST0_CU1);
 	childregs->cp0_status &= ~(ST0_CU2|ST0_CU1);
+
+#ifdef CONFIG_MIPS_MT_SMTC
+	/*
+	 * SMTC restores TCStatus after Status, and the CU bits
+	 * are aliased there.
+	 */
+	childregs->cp0_tcstatus &= ~(ST0_CU2|ST0_CU1);
+#endif
 	clear_tsk_thread_flag(p, TIF_USEDFPU);
 
 #ifdef CONFIG_MIPS_MT_FPAFF
 	clear_tsk_thread_flag(p, TIF_FPUBOUND);
-
-	/*
-	 * FPU affinity support is cleaner if we track the
-	 * user-visible CPU affinity from the very beginning.
-	 * The generic cpus_allowed mask will already have
-	 * been copied from the parent before copy_thread
-	 * is invoked.
-	 */
-	p->thread.user_cpus_allowed = p->cpus_allowed;
 #endif /* CONFIG_MIPS_MT_FPAFF */
 
 	if (clone_flags & CLONE_SETTLS)

arch/mips/kernel/traps.c

@@ -825,8 +825,10 @@ static void mt_ase_fp_affinity(void)
 		if (cpus_intersects(current->cpus_allowed, mt_fpu_cpumask)) {
 			cpumask_t tmask;
 
-			cpus_and(tmask, current->thread.user_cpus_allowed,
-			         mt_fpu_cpumask);
+			current->thread.user_cpus_allowed
+				= current->cpus_allowed;
+			cpus_and(tmask, current->cpus_allowed,
+				mt_fpu_cpumask);
 			set_cpus_allowed(current, tmask);
 			set_thread_flag(TIF_FPUBOUND);
 		}