[rtems commit] bsps/arm: Invalidate branch predictors earlier

[Sebastian Huber]

Module:    rtems
Branch:    master
Commit:    76a1a5378031e56d29d16c713aee73c6747c3e61
Changeset: http://git.rtems.org/rtems/commit/?id=76a1a5378031e56d29d16c713aee73c6747c3e61

Author:    Sebastian Huber <sebastian.huber at embedded-brains.de>
Date:      Mon Dec 21 07:29:41 2020 +0100

bsps/arm: Invalidate branch predictors earlier

Make sure the branch predictors are invalidated before the first branch
is executed.

Update #4202.

---

 bsps/arm/include/bsp/arm-a9mpcore-start.h    |  2 --
 bsps/arm/raspberrypi/start/bspstarthooks.c   |  1 -
 bsps/arm/shared/start/start.S                | 11 +++++++++++
 bsps/arm/xilinx-zynq/start/bspstarthooks.c   |  1 -
 bsps/arm/xilinx-zynqmp/start/bspstarthooks.c |  1 -
 5 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/bsps/arm/include/bsp/arm-a9mpcore-start.h b/bsps/arm/include/bsp/arm-a9mpcore-start.h
index f377745..38ddb03 100644
--- a/bsps/arm/include/bsp/arm-a9mpcore-start.h
+++ b/bsps/arm/include/bsp/arm-a9mpcore-start.h
@@ -141,8 +141,6 @@ BSP_START_TEXT_SECTION static inline void arm_a9mpcore_start_hook_0(void)
     (volatile a9mpcore_scu *) BSP_ARM_A9MPCORE_SCU_BASE;
   uint32_t cpu_id = arm_cortex_a9_get_multiprocessor_cpu_id();
 
-  arm_cp15_branch_predictor_invalidate_all();
-
   if (cpu_id == 0) {
     arm_a9mpcore_start_scu_enable(scu);
   }
diff --git a/bsps/arm/raspberrypi/start/bspstarthooks.c b/bsps/arm/raspberrypi/start/bspstarthooks.c
index c46c4f5..b050cb6 100644
--- a/bsps/arm/raspberrypi/start/bspstarthooks.c
+++ b/bsps/arm/raspberrypi/start/bspstarthooks.c
@@ -110,7 +110,6 @@ void BSP_START_TEXT_SECTION bsp_start_hook_0(void)
     rtems_cache_invalidate_entire_data();
   }
   rtems_cache_invalidate_entire_instruction();
-  arm_cp15_branch_predictor_invalidate_all();
   arm_cp15_tlb_invalidate();
   arm_cp15_flush_prefetch_buffer();
 
diff --git a/bsps/arm/shared/start/start.S b/bsps/arm/shared/start/start.S
index 9ebc281..f4880df 100644
--- a/bsps/arm/shared/start/start.S
+++ b/bsps/arm/shared/start/start.S
@@ -181,6 +181,17 @@ _start:
 	mov	r13, #0
 #endif
 
+#if __ARM_ARCH >= 7
+	/*
+	 * Write to BPIALL (Branch Predictor Invalidate All) to invalidate all
+	 * branch predictors.  There is no need to use BPIALLIS (Branch
+	 * Predictor Invalidate All, Inner Shareable) since this code is
+	 * executed on all processors used by RTEMS.
+	 */
+	mov	r0, #0
+	mcr	p15, 0, r0, c7, c5, 6
+#endif
+
 #ifdef RTEMS_SMP
 	/* Read MPIDR and get current processor index */
 	mrc	p15, 0, r7, c0, c0, 5
diff --git a/bsps/arm/xilinx-zynq/start/bspstarthooks.c b/bsps/arm/xilinx-zynq/start/bspstarthooks.c
index a0f0fba..0fc2a25 100644
--- a/bsps/arm/xilinx-zynq/start/bspstarthooks.c
+++ b/bsps/arm/xilinx-zynq/start/bspstarthooks.c
@@ -66,7 +66,6 @@ BSP_START_TEXT_SECTION void bsp_start_hook_0(void)
    * are required there.
    */
   arm_cp15_data_cache_invalidate_all_levels();
-  arm_cp15_branch_predictor_invalidate_all();
   arm_cp15_tlb_invalidate();
   arm_cp15_flush_prefetch_buffer();
   arm_a9mpcore_start_hook_0();
diff --git a/bsps/arm/xilinx-zynqmp/start/bspstarthooks.c b/bsps/arm/xilinx-zynqmp/start/bspstarthooks.c
index 9ab8d96..bc3f0fb 100644
--- a/bsps/arm/xilinx-zynqmp/start/bspstarthooks.c
+++ b/bsps/arm/xilinx-zynqmp/start/bspstarthooks.c
@@ -72,7 +72,6 @@ BSP_START_TEXT_SECTION void bsp_start_hook_0(void)
    * are required there.
    */
   arm_cp15_data_cache_invalidate_all_levels();
-  arm_cp15_branch_predictor_invalidate_all();
   arm_cp15_tlb_invalidate();
   arm_cp15_flush_prefetch_buffer();
 }