sh: Fix occasional FPU register corruption under preempt.

Presently with preempt enabled there's the possibility to be preempted
after the TIF_USEDFPU test and the register save, leading to bogus
state post-__switch_to(). Use an explicit preempt_disable()/enable()
pair around unlazy_fpu()/clear_fpu() to avoid this. Follows the x86
change.

Reported-by: Takuo Koguchi <takuo.koguchi.sw@hitachi.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/asm-sh/processor_64.h b/include/asm-sh/processor_64.h
index eda4bef448e9..88a2edf8fa5d 100644
--- a/include/asm-sh/processor_64.h
+++ b/include/asm-sh/processor_64.h
@@ -112,6 +112,7 @@ extern struct sh_cpuinfo cpu_data[];
 #endif
 
 #define SR_IMASK 0x000000f0
+#define SR_FD    0x00008000
 #define SR_SSTEP 0x08000000
 
 #ifndef __ASSEMBLY__