sof: align sof structure to cache line size

Aligns sof structure to cache line size. It is needed
in order to assure that no data will be randomly overwritten
by cache eviction with multicore access.

Signed-off-by: Tomasz Lauda <tomasz.lauda@linux.intel.com>

Author: tlauda

src/include/sof/sof.h

@@ -9,12 +9,20 @@
 #define __SOF_SOF_H__
 
 #include <arch/sof.h>
+#include <sof/common.h>
+#include <sof/lib/memory.h>
 
 struct dma_trace_data;
 struct ipc;
 struct sa;
 
-/* general firmware context */
+/**
+ * \brief General firmware context.
+ * This structure holds all the global pointers, which can potentially
+ * be accessed by SMP code, hence it should be aligned to platform's
+ * data cache line size. Alignments in the both beginning and end are needed
+ * to avoid potential before and after data evictions.
+ */
 struct sof {
 	/* init data */
 	int argc;
@@ -28,6 +36,8 @@ struct sof {
 
 	/* DMA for Trace*/
 	struct dma_trace_data *dmat;
-};
+
+	__aligned(PLATFORM_DCACHE_ALIGN) int alignment[0];
+} __aligned(PLATFORM_DCACHE_ALIGN);
 
 #endif /* __SOF_SOF_H__ */