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Diffstat (limited to '')
-rw-r--r-- | plat/arm/board/fvp_r/fvp_r_context_mgmt.c | 53 |
1 files changed, 53 insertions, 0 deletions
diff --git a/plat/arm/board/fvp_r/fvp_r_context_mgmt.c b/plat/arm/board/fvp_r/fvp_r_context_mgmt.c new file mode 100644 index 0000000..d172d2d --- /dev/null +++ b/plat/arm/board/fvp_r/fvp_r_context_mgmt.c @@ -0,0 +1,53 @@ +/* + * Copyright (c) 2021, ARM Limited and Contributors. All rights reserved. + * + * SPDX-License-Identifier: BSD-3-Clause + */ + +#include <arch_helpers.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); + + /* + * 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); + + /* + * 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); +} |