Initialise cpu ops after enabling data cache

The cpu-ops pointer was initialized before enabling the data cache in the cold
and warm boot paths. This required a DCIVAC cache maintenance operation to
invalidate any stale cache lines resident in other cpus.

This patch moves this initialization to the bl31_arch_setup() function
which is always called after the data cache and MMU has been enabled.

This change removes the need:
 1. for the DCIVAC cache maintenance operation.
 2. to initialise the CPU ops upon resumption from a PSCI CPU_SUSPEND
    call since memory contents are always preserved in this case.

Change-Id: Ibb2fa2f7460d1a1f1e721242025e382734c204c6

bl31/aarch64/bl31_arch_setup.c

@@ -33,6 +33,7 @@
 #include <assert.h>
 #include <bl_common.h>
 #include <bl31.h>
+#include <cpu_data.h>
 #include <platform.h>
 
 /*******************************************************************************
@@ -47,4 +48,7 @@ void bl31_arch_setup(void)
 
 	/* Program the counter frequency */
 	write_cntfrq_el0(plat_get_syscnt_freq());
+
+	/* Initialize the cpu_ops pointer. */
+	init_cpu_ops();
 }

bl31/aarch64/bl31_entrypoint.S

@@ -161,12 +161,6 @@ func bl31_entrypoint
 	bl	zeromem16
 #endif
 
-	/* ---------------------------------------------
-	 * Initialize the cpu_ops pointer.
-	 * ---------------------------------------------
-	 */
-	bl	init_cpu_ops
-
 	/* ---------------------------------------------
 	 * Use SP_EL0 for the C runtime stack.
 	 * ---------------------------------------------

include/bl31/cpu_data.h

@@ -117,6 +117,7 @@ static inline struct cpu_data *_cpu_data(void)
  *************************************************************************/
 
 void init_cpu_data_ptr(void);
+void init_cpu_ops(void);
 
 #define get_cpu_data(_m)		   _cpu_data()->_m
 #define set_cpu_data(_m, _v)		   _cpu_data()->_m = _v

lib/cpus/aarch64/cpu_helpers.S

@@ -110,7 +110,8 @@ func prepare_cluster_pwr_dwn
 
 	/*
 	 * Initializes the cpu_ops_ptr if not already initialized
-	 * in cpu_data. This can be called without a runtime stack.
+	 * in cpu_data. This can be called without a runtime stack, but may
+	 * only be called after the MMU is enabled.
 	 * clobbers: x0 - x6, x10
 	 */
 	.globl	init_cpu_ops
@@ -125,18 +126,6 @@ func init_cpu_ops
 	ASM_ASSERT(ne)
 #endif
 	str	x0, [x6, #CPU_DATA_CPU_OPS_PTR]!
-
-	/*
-	 * Make sure that any pre-fetched cache copies are invalidated.
-	 * Ensure that we are running with cache disable else we
-	 * invalidate our own update.
-	 */
-#if ASM_ASSERTION
-	mrs	x1, sctlr_el3
-	tst	x1, #SCTLR_C_BIT
-	ASM_ASSERT(eq)
-#endif
-	dc	ivac, x6
 	mov x30, x10
 1:
 	ret

services/std_svc/psci/psci_entry.S

@@ -86,12 +86,6 @@ psci_aff_common_finish_entry:
 	 */
 	bl	init_cpu_data_ptr
 
-	/* ---------------------------------------------
-	 * Initialize the cpu_ops pointer.
-	 * ---------------------------------------------
-	 */
-	bl	init_cpu_ops
-
 	/* ---------------------------------------------
 	 * Set the exception vectors
 	 * ---------------------------------------------