[ARM] Optimise VFP thread notify function a little
The common case for the thread notifier is a context switch. Tell
gcc that this is the most likely condition so it can optimise the
function for this case.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/vfp/vfpmodule.c b/arch/arm/vfp/vfpmodule.c
index 4178f6c..dedbb44 100644
--- a/arch/arm/vfp/vfpmodule.c
+++ b/arch/arm/vfp/vfpmodule.c
@@ -40,10 +40,19 @@
static int vfp_notifier(struct notifier_block *self, unsigned long cmd, void *v)
{
struct thread_info *thread = v;
- union vfp_state *vfp = &thread->vfpstate;
+ union vfp_state *vfp;
- switch (cmd) {
- case THREAD_NOTIFY_FLUSH:
+ if (likely(cmd == THREAD_NOTIFY_SWITCH)) {
+ /*
+ * Always disable VFP so we can lazily save/restore the
+ * old state.
+ */
+ fmxr(FPEXC, fmrx(FPEXC) & ~FPEXC_ENABLE);
+ return NOTIFY_DONE;
+ }
+
+ vfp = &thread->vfpstate;
+ if (cmd == THREAD_NOTIFY_FLUSH) {
/*
* Per-thread VFP initialisation.
*/
@@ -56,29 +65,12 @@
* Disable VFP to ensure we initialise it first.
*/
fmxr(FPEXC, fmrx(FPEXC) & ~FPEXC_ENABLE);
-
- /*
- * FALLTHROUGH: Ensure we don't try to overwrite our newly
- * initialised state information on the first fault.
- */
-
- case THREAD_NOTIFY_RELEASE:
- /*
- * Per-thread VFP cleanup.
- */
- if (last_VFP_context == vfp)
- last_VFP_context = NULL;
- break;
-
- case THREAD_NOTIFY_SWITCH:
- /*
- * Always disable VFP so we can lazily save/restore the
- * old state.
- */
- fmxr(FPEXC, fmrx(FPEXC) & ~FPEXC_ENABLE);
- break;
}
+ /* flush and release case: Per-thread VFP cleanup. */
+ if (last_VFP_context == vfp)
+ last_VFP_context = NULL;
+
return NOTIFY_DONE;
}