diff --git a/arch/mips/kernel/ptrace.c b/arch/mips/kernel/ptrace.c
index f639ccd5060c..3a7f7dd610fd 100644
--- a/arch/mips/kernel/ptrace.c
+++ b/arch/mips/kernel/ptrace.c
@@ -151,6 +151,7 @@ int ptrace_setfpregs(struct task_struct *child, __u32 __user *data)
 	}
 
 	__get_user(child->thread.fpu.fcr31, data + 64);
+	child->thread.fpu.fcr31 &= ~FPU_CSR_ALL_X;
 
 	/* FIR may not be written.  */
 
@@ -565,7 +566,7 @@ long arch_ptrace(struct task_struct *child, long request,
 			break;
 #endif
 		case FPC_CSR:
-			child->thread.fpu.fcr31 = data;
+			child->thread.fpu.fcr31 = data & ~FPU_CSR_ALL_X;
 			break;
 		case DSP_BASE ... DSP_BASE + 5: {
 			dspreg_t *dregs;