powerpc/e500: Save SPEFCSR in flush_spe_to_thread()

giveup_spe() saves the SPE state which is protected by MSR[SPE].
However, modifying SPEFSCR does not trap when MSR[SPE]=0.
And since SPEFSCR is already saved/restored in _switch(),
not all the callers want to save SPEFSCR again.
Thus, saving SPEFSCR should not belong to giveup_spe().

This patch moves SPEFSCR saving to flush_spe_to_thread(),
and cleans up the caller that needs to save SPEFSCR accordingly.

Signed-off-by: Liu Yu <yu.liu@freescale.com>
Acked-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>

3 files changed, 2 insertions, 6 deletions

diff --git a/arch/powerpc/kernel/head_fsl_booke.S b/arch/powerpc/kernel/head_fsl_booke.S
index 5ecf54cfa7d4..aede4f87b682 100644
--- a/arch/powerpc/kernel/head_fsl_booke.S
+++ b/arch/powerpc/kernel/head_fsl_booke.S
@@ -792,8 +792,6 @@ _GLOBAL(giveup_spe)
         evmwumiaa evr6, evr6, evr6      /* evr6 <- ACC = 0 * 0 + ACC */
         li      r4,THREAD_ACC
         evstddx evr6, r4, r3            /* save off accumulator */
-        mfspr   r6,SPRN_SPEFSCR
-        stw     r6,THREAD_SPEFSCR(r3)   /* save spefscr register value */
         beq     1f
         lwz     r4,_MSR-STACK_FRAME_OVERHEAD(r5)
         lis     r3,MSR_SPE@h
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 91e52df3d81d..60ac2a9251db 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -213,6 +213,7 @@ void flush_spe_to_thread(struct task_struct *tsk)
 #ifdef CONFIG_SMP
                         BUG_ON(tsk != current);
 #endif
+                        tsk->thread.spefscr = mfspr(SPRN_SPEFSCR);
                         giveup_spe(tsk);
                 }
                 preempt_enable();
diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index 1a0141426cda..f19d9777d3c1 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -1387,10 +1387,7 @@ void SPEFloatingPointException(struct pt_regs *regs)
         int code = 0;
         int err;
 
-        preempt_disable();
-        if (regs->msr & MSR_SPE)
-                giveup_spe(current);
-        preempt_enable();
+        flush_spe_to_thread(current);
 
         spefscr = current->thread.spefscr;
         fpexc_mode = current->thread.fpexc_mode;