[MIPS] Check FCSR for pending interrupts before restoring from a context.

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

1 files changed, 16 insertions, 0 deletions

diff --git a/arch/mips/kernel/r4k_fpu.S b/arch/mips/kernel/r4k_fpu.S
index 880fa6e841ee..8b5ccfa99dd1 100644
--- a/arch/mips/kernel/r4k_fpu.S
+++ b/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)