[MIPS] Check FCSR for pending interrupts before restoring from a cont…

…ext.

Signed-off-by: Chris Dearman <chris@mips.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/kernel/r4k_fpu.S

@@ -114,6 +114,14 @@ LEAF(_save_fp_context32)
  */
 LEAF(_restore_fp_context)
 	EX	lw t0, SC_FPC_CSR(a0)
+
+	/* Fail if the CSR has exceptions pending */
+	srl	t1, t0, 5
+	and	t1, t0
+	andi	t1, 0x1f << 7
+	bnez	t1, fault
+	 nop
+
 #ifdef CONFIG_64BIT
 	EX	ldc1 $f1, SC_FPREGS+8(a0)
 	EX	ldc1 $f3, SC_FPREGS+24(a0)
@@ -157,6 +165,14 @@ LEAF(_restore_fp_context)
 LEAF(_restore_fp_context32)
 	/* Restore an o32 sigcontext.  */
 	EX	lw t0, SC32_FPC_CSR(a0)
+
+	/* Fail if the CSR has exceptions pending */
+	srl	t1, t0, 5
+	and	t1, t0
+	andi	t1, 0x1f << 7
+	bnez	t1, fault
+	 nop
+
 	EX	ldc1 $f0, SC32_FPREGS+0(a0)
 	EX	ldc1 $f2, SC32_FPREGS+16(a0)
 	EX	ldc1 $f4, SC32_FPREGS+32(a0)