--- zzzz-none-000/linux-3.10.107/arch/mips/math-emu/kernel_linkage.c	2017-06-27 09:49:32.000000000 +0000
+++ vr9-7490-729/linux-3.10.107/arch/mips/math-emu/kernel_linkage.c	2021-11-10 11:53:54.000000000 +0000
@@ -27,7 +27,21 @@
 #include <asm/fpu.h>
 #include <asm/fpu_emulator.h>
 
-#define SIGNALLING_NAN 0x7ff800007ff80000LL
+#define SIGNALLING_NAN      0x7ff800007ff80000LL
+#define SIGNALLING_NAN2008  0x7ff000007fa00000LL
+
+extern unsigned int fpu_fcr31 __read_mostly;
+extern unsigned int system_has_fpu __read_mostly;
+static int nan2008 __read_mostly = -1;
+
+static int __init setup_nan2008(char *str)
+{
+	get_option (&str, &nan2008);
+
+	return 1;
+}
+
+__setup("nan2008=", setup_nan2008);
 
 void fpu_emulator_init_fpu(void)
 {
@@ -39,10 +53,28 @@
 		printk("Algorithmics/MIPS FPU Emulator v1.5\n");
 	}
 
-	current->thread.fpu.fcr31 = 0;
-	for (i = 0; i < 32; i++) {
-		current->thread.fpu.fpr[i] = SIGNALLING_NAN;
+	if (system_has_fpu)
+		current->thread.fpu.fcr31 = fpu_fcr31;
+	else if (nan2008 < 0) {
+		if (!test_thread_flag(TIF_32BIT_REGS))
+			current->thread.fpu.fcr31 = FPU_CSR_DEFAULT|FPU_CSR_MAC2008|FPU_CSR_ABS2008|FPU_CSR_NAN2008;
+		else
+			current->thread.fpu.fcr31 = FPU_CSR_DEFAULT;
+	} else {
+		if (nan2008)
+			current->thread.fpu.fcr31 = FPU_CSR_DEFAULT|FPU_CSR_MAC2008|FPU_CSR_ABS2008|FPU_CSR_NAN2008;
+		else
+			current->thread.fpu.fcr31 = FPU_CSR_DEFAULT;
 	}
+
+	if (current->thread.fpu.fcr31 & FPU_CSR_NAN2008)
+		for (i = 0; i < 32; i++) {
+			current->thread.fpu.fpr[i] = SIGNALLING_NAN2008;
+		}
+	else
+		for (i = 0; i < 32; i++) {
+			current->thread.fpu.fpr[i] = SIGNALLING_NAN;
+		}
 }
 
 
@@ -90,6 +122,17 @@
 	int i;
 	int err = 0;
 
+	if (!test_thread_flag(TIF_32BIT_REGS)) {
+		for (i = 0; i < 32; i++) {
+			err |=
+			    __put_user(current->thread.fpu.fpr[i], &sc->sc_fpregs[i]);
+		}
+		err |= __put_user(current->thread.fpu.fcr31, &sc->sc_fpc_csr);
+
+		return err;
+
+	}
+
 	for (i = 0; i < 32; i+=2) {
 		err |=
 		    __put_user(current->thread.fpu.fpr[i], &sc->sc_fpregs[i]);
@@ -104,6 +147,16 @@
 	int i;
 	int err = 0;
 
+	if (!test_thread_flag(TIF_32BIT_REGS)) {
+		for (i = 0; i < 32; i++) {
+			err |=
+			    __get_user(current->thread.fpu.fpr[i], &sc->sc_fpregs[i]);
+		}
+		err |= __get_user(current->thread.fpu.fcr31, &sc->sc_fpc_csr);
+
+		return err;
+	}
+
 	for (i = 0; i < 32; i+=2) {
 		err |=
 		    __get_user(current->thread.fpu.fpr[i], &sc->sc_fpregs[i]);