feat(fvp_r): configure system registers to boot rich OS
Following system registers are modified before exiting EL2 to allow
u-boot/Linux to boot
1. CNTHCTL_EL2.EL1PCTEN -> 1
Allows U-boot to use physical counters at EL1
2. VTCR_EL2.MSA -> 1
Enables VMSA at EL1, which is required by U-Boot and Linux.
3. HCR_EL2.APK = 1 & HCR_EL2.API = 1
Disables PAuth instruction and register traps in EL1
Signed-off-by: Manish Pandey <manish.pandey2@arm.com>
Change-Id: I58f45b6669a9ad1debb80265b243015c054a9bb1
diff --git a/plat/arm/board/fvp_r/fvp_r_bl1_context_mgmt.c b/plat/arm/board/fvp_r/fvp_r_bl1_context_mgmt.c
index 7ae853b..c6544b4 100644
--- a/plat/arm/board/fvp_r/fvp_r_bl1_context_mgmt.c
+++ b/plat/arm/board/fvp_r/fvp_r_bl1_context_mgmt.c
@@ -15,7 +15,7 @@
#include <plat/common/platform.h>
-void cm_prepare_el2_exit(uint32_t security_state);
+void cm_prepare_el2_exit(void);
/* Following contains the cpu context pointers. */
static void *bl1_cpu_context_ptr[2];
@@ -81,6 +81,9 @@
/* Allow platform to make change */
bl1_plat_set_ep_info(image_id, next_bl_ep);
+ /* Prepare context for the next EL */
+ cm_prepare_el2_exit();
+
/* Indicate that image is in execution state. */
desc->state = IMAGE_STATE_EXECUTED;
diff --git a/plat/arm/board/fvp_r/fvp_r_context_mgmt.c b/plat/arm/board/fvp_r/fvp_r_context_mgmt.c
index 678b879..d172d2d 100644
--- a/plat/arm/board/fvp_r/fvp_r_context_mgmt.c
+++ b/plat/arm/board/fvp_r/fvp_r_context_mgmt.c
@@ -4,25 +4,50 @@
* SPDX-License-Identifier: BSD-3-Clause
*/
-#include <lib/el3_runtime/context_mgmt.h>
-#include <lib/el3_runtime/pubsub_events.h>
+#include <arch_helpers.h>
-#include <platform_def.h>
+/************************************************************
+ * For R-class everything is in secure world.
+ * Prepare the CPU system registers for first entry into EL1
+ ************************************************************/
+void cm_prepare_el2_exit(void)
+{
+ uint64_t hcr_el2 = 0U;
+ /*
+ * The use of ARMv8.3 pointer authentication (PAuth) is governed
+ * by fields in HCR_EL2, which trigger a 'trap to EL2' if not
+ * enabled. This register initialized at boot up, update PAuth
+ * bits.
+ *
+ * HCR_API_BIT: Set to one to disable traps to EL2 if lower ELs
+ * access PAuth registers
+ *
+ * HCR_APK_BIT: Set to one to disable traps to EL2 if lower ELs
+ * access PAuth instructions
+ */
+ hcr_el2 = read_hcr_el2();
+ write_hcr_el2(hcr_el2 | HCR_API_BIT | HCR_APK_BIT);
-/*******************************************************************************
- * File contains EL2 equivalents of EL3 functions from
- * .../lib/el3_runtime/aarch64/context_mgmt.c
- ******************************************************************************/
+ /*
+ * Initialise CNTHCTL_EL2. All fields are architecturally UNKNOWN
+ * on reset and are set to zero except for field(s) listed below.
+ *
+ * CNTHCTL_EL2.EL1PCEN: Set to one to disable traps to EL2
+ * if lower ELs accesses to the physical timer registers.
+ *
+ * CNTHCTL_EL2.EL1PCTEN: Set to one to disable traps to EL2
+ * if lower ELs access to the physical counter registers.
+ */
+ write_cnthctl_el2(CNTHCTL_RESET_VAL | EL1PCEN_BIT | EL1PCTEN_BIT);
-/*******************************************************************************
- * Prepare the CPU system registers for first entry into secure or normal world
- *
- * The majority of the work needed is only for switching to non-secure, which
- * is not available on v8-R64 cores, so this function is very simple.
- ******************************************************************************/
-void cm_prepare_el2_exit(uint32_t security_state)
-{
- cm_el1_sysregs_context_restore(security_state);
- cm_set_next_eret_context(security_state);
+ /*
+ * On Armv8-R, the EL1&0 memory system architecture is configurable
+ * as a VMSA or PMSA. All the fields architecturally UNKNOWN on reset
+ * and are set to zero except for field listed below.
+ *
+ * VCTR_EL2.MSA: Set to one to ensure the VMSA is enabled so that
+ * rich OS can boot.
+ */
+ write_vtcr_el2(VTCR_RESET_VAL | VTCR_EL2_MSA);
}