ARM: vfp: ensure that thread flushing works if preempted

[pandora-kernel.git] / arch / arm / vfp / vfpmodule.c

diff --git a/arch/arm/vfp/vfpmodule.c b/arch/arm/vfp/vfpmodule.c
index 08ff93f..0a96f71 100644 (file)
--- a/arch/arm/vfp/vfpmodule.c
+++ b/arch/arm/vfp/vfpmodule.c
@@ -89,24 +89,27 @@ static void vfp_thread_flush(struct thread_info *thread)
        union vfp_state *vfp = &thread->vfpstate;
        unsigned int cpu;
 
-       memset(vfp, 0, sizeof(union vfp_state));
-
-       vfp->hard.fpexc = FPEXC_EN;
-       vfp->hard.fpscr = FPSCR_ROUND_NEAREST;
-#ifdef CONFIG_SMP
-       vfp->hard.cpu = NR_CPUS;
-#endif
-
        /*
         * Disable VFP to ensure we initialize it first.  We must ensure
-        * that the modification of vfp_current_hw_state[] and hardware disable
-        * are done for the same CPU and without preemption.
+        * that the modification of vfp_current_hw_state[] and hardware
+        * disable are done for the same CPU and without preemption.
+        *
+        * Do this first to ensure that preemption won't overwrite our
+        * state saving should access to the VFP be enabled at this point.
         */
        cpu = get_cpu();
        if (vfp_current_hw_state[cpu] == vfp)
                vfp_current_hw_state[cpu] = NULL;
        fmxr(FPEXC, fmrx(FPEXC) & ~FPEXC_EN);
        put_cpu();
+
+       memset(vfp, 0, sizeof(union vfp_state));
+
+       vfp->hard.fpexc = FPEXC_EN;
+       vfp->hard.fpscr = FPSCR_ROUND_NEAREST;
+#ifdef CONFIG_SMP
+       vfp->hard.cpu = NR_CPUS;
+#endif
 }
 
 static void vfp_thread_exit(struct thread_info *thread)