MIPS: Avoid an FPE exception in FCSR mask probing

Use the default FCSR value in mask probing, avoiding an FPE exception
where reset has left any exception enable and their corresponding cause
bits set and the register is then rewritten with these bits active.

Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Cc: Joshua Kinard <kumba@gentoo.org>
Cc: linux-mips@linux-mips.org
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

diff --git a/arch/mips/kernel/cpu-probe.c b/arch/mips/kernel/cpu-probe.c
index e36515dcd3b29efcdb0014c7dfd4541805eb4e4c..209e5b76c1bce56f02ceeb1fdeffeccc6fe46bd8 100644 (file)
--- a/arch/mips/kernel/cpu-probe.c
+++ b/arch/mips/kernel/cpu-probe.c
@@ -74,13 +74,12 @@ static inline void cpu_set_fpu_fcsr_mask(struct cpuinfo_mips *c)
 {
        unsigned long sr, mask, fcsr, fcsr0, fcsr1;
 
+       fcsr = c->fpu_csr31;
        mask = FPU_CSR_ALL_X | FPU_CSR_ALL_E | FPU_CSR_ALL_S | FPU_CSR_RM;
 
        sr = read_c0_status();
        __enable_fpu(FPU_AS_IS);
 
-       fcsr = read_32bit_cp1_register(CP1_STATUS);
-
        fcsr0 = fcsr & mask;
        write_32bit_cp1_register(CP1_STATUS, fcsr0);
        fcsr0 = read_32bit_cp1_register(CP1_STATUS);