1 files changed, 49 insertions, 0 deletions

diff --git a/arch/arm/vfp/vfpmodule.c b/arch/arm/vfp/vfpmodule.c
index 9f476a1be2ca..7e1239041b39 100644
--- a/arch/arm/vfp/vfpmodule.c
+++ b/arch/arm/vfp/vfpmodule.c
@@ -377,6 +377,55 @@ static void vfp_pm_init(void)
 static inline void vfp_pm_init(void) { }
 #endif /* CONFIG_PM */
 
+/*
+ * Synchronise the hardware VFP state of a thread other than current with the
+ * saved one. This function is used by the ptrace mechanism.
+ */
+#ifdef CONFIG_SMP
+void vfp_sync_state(struct thread_info *thread)
+{
+        /*
+         * On SMP systems, the VFP state is automatically saved at every
+         * context switch. We mark the thread VFP state as belonging to a
+         * non-existent CPU so that the saved one will be reloaded when
+         * needed.
+         */
+        thread->vfpstate.hard.cpu = NR_CPUS;
+}
+#else
+void vfp_sync_state(struct thread_info *thread)
+{
+        unsigned int cpu = get_cpu();
+        u32 fpexc = fmrx(FPEXC);
+
+        /*
+         * If VFP is enabled, the previous state was already saved and
+         * last_VFP_context updated.
+         */
+        if (fpexc & FPEXC_EN)
+                goto out;
+
+        if (!last_VFP_context[cpu])
+                goto out;
+
+        /*
+         * Save the last VFP state on this CPU.
+         */
+        fmxr(FPEXC, fpexc | FPEXC_EN);
+        vfp_save_state(last_VFP_context[cpu], fpexc);
+        fmxr(FPEXC, fpexc);
+
+        /*
+         * Set the context to NULL to force a reload the next time the thread
+         * uses the VFP.
+         */
+        last_VFP_context[cpu] = NULL;
+
+out:
+        put_cpu();
+}
+#endif
+
 #include <linux/smp.h>
 
 /*