[ARM] 4111/1: Allow VFP to work with thread migration on SMP

[linux-2.6-omap-h63xx.git] / arch / arm / vfp / vfpmodule.c

diff --git a/arch/arm/vfp/vfpmodule.c b/arch/arm/vfp/vfpmodule.c
index 490d9d18a7d1c166dbef16e988050ec870e406a8..f1e5951dc72188ce86c9ae880ccbef79621ae327 100644 (file)
--- a/arch/arm/vfp/vfpmodule.c
+++ b/arch/arm/vfp/vfpmodule.c
@@ -28,7 +28,7 @@ void vfp_testing_entry(void);
 void vfp_support_entry(void);
 
 void (*vfp_vector)(void) = vfp_testing_entry;
-union vfp_state *last_VFP_context;
+union vfp_state *last_VFP_context[NR_CPUS];
 
 /*
  * Dual-use variable.
@@ -41,13 +41,35 @@ static int vfp_notifier(struct notifier_block *self, unsigned long cmd, void *v)
 {
        struct thread_info *thread = v;
        union vfp_state *vfp;
+       __u32 cpu = thread->cpu;
 
        if (likely(cmd == THREAD_NOTIFY_SWITCH)) {
+               u32 fpexc = fmrx(FPEXC);
+
+#ifdef CONFIG_SMP
+               /*
+                * On SMP, if VFP is enabled, save the old state in
+                * case the thread migrates to a different CPU. The
+                * restoring is done lazily.
+                */
+               if ((fpexc & FPEXC_ENABLE) && last_VFP_context[cpu]) {
+                       vfp_save_state(last_VFP_context[cpu], fpexc);
+                       last_VFP_context[cpu]->hard.cpu = cpu;
+               }
+               /*
+                * Thread migration, just force the reloading of the
+                * state on the new CPU in case the VFP registers
+                * contain stale data.
+                */
+               if (thread->vfpstate.hard.cpu != cpu)
+                       last_VFP_context[cpu] = NULL;
+#endif
+
                /*
                 * Always disable VFP so we can lazily save/restore the
                 * old state.
                 */
-               fmxr(FPEXC, fmrx(FPEXC) & ~FPEXC_ENABLE);
+               fmxr(FPEXC, fpexc & ~FPEXC_ENABLE);
                return NOTIFY_DONE;
        }
 
@@ -68,8 +90,8 @@ static int vfp_notifier(struct notifier_block *self, unsigned long cmd, void *v)
        }
 
        /* flush and release case: Per-thread VFP cleanup. */
-       if (last_VFP_context == vfp)
-               last_VFP_context = NULL;
+       if (last_VFP_context[cpu] == vfp)
+               last_VFP_context[cpu] = NULL;
 
        return NOTIFY_DONE;
 }