diff options
Diffstat (limited to 'lib/el3_runtime/aarch32/context_mgmt.c')
| -rw-r--r-- | lib/el3_runtime/aarch32/context_mgmt.c | 287 |
1 files changed, 287 insertions, 0 deletions
diff --git a/lib/el3_runtime/aarch32/context_mgmt.c b/lib/el3_runtime/aarch32/context_mgmt.c new file mode 100644 index 00000000..3e7a5b73 --- /dev/null +++ b/lib/el3_runtime/aarch32/context_mgmt.c @@ -0,0 +1,287 @@ +/* + * Copyright (c) 2016-2017, ARM Limited and Contributors. All rights reserved. + * + * SPDX-License-Identifier: BSD-3-Clause + */ + +#include <arch.h> +#include <arch_helpers.h> +#include <assert.h> +#include <bl_common.h> +#include <context.h> +#include <context_mgmt.h> +#include <platform.h> +#include <platform_def.h> +#include <smcc_helpers.h> +#include <string.h> +#include <utils.h> + +/******************************************************************************* + * Context management library initialisation routine. This library is used by + * runtime services to share pointers to 'cpu_context' structures for the secure + * and non-secure states. Management of the structures and their associated + * memory is not done by the context management library e.g. the PSCI service + * manages the cpu context used for entry from and exit to the non-secure state. + * The Secure payload manages the context(s) corresponding to the secure state. + * It also uses this library to get access to the non-secure + * state cpu context pointers. + ******************************************************************************/ +void cm_init(void) +{ + /* + * The context management library has only global data to initialize, but + * that will be done when the BSS is zeroed out + */ +} + +/******************************************************************************* + * The following function initializes the cpu_context 'ctx' for + * first use, and sets the initial entrypoint state as specified by the + * entry_point_info structure. + * + * The security state to initialize is determined by the SECURE attribute + * of the entry_point_info. The function returns a pointer to the initialized + * context and sets this as the next context to return to. + * + * The EE and ST attributes are used to configure the endianness and secure + * timer availability for the new execution context. + * + * To prepare the register state for entry call cm_prepare_el3_exit() and + * el3_exit(). For Secure-EL1 cm_prepare_el3_exit() is equivalent to + * cm_e1_sysreg_context_restore(). + ******************************************************************************/ +static void cm_init_context_common(cpu_context_t *ctx, const entry_point_info_t *ep) +{ + unsigned int security_state; + uint32_t scr, sctlr; + regs_t *reg_ctx; + + assert(ctx); + + security_state = GET_SECURITY_STATE(ep->h.attr); + + /* Clear any residual register values from the context */ + zeromem(ctx, sizeof(*ctx)); + + reg_ctx = get_regs_ctx(ctx); + + /* + * Base the context SCR on the current value, adjust for entry point + * specific requirements + */ + scr = read_scr(); + scr &= ~(SCR_NS_BIT | SCR_HCE_BIT); + + if (security_state != SECURE) + scr |= SCR_NS_BIT; + + if (security_state != SECURE) { + /* + * Set up SCTLR for the Non-secure context. + * + * SCTLR.EE: Endianness is taken from the entrypoint attributes. + * + * SCTLR.M, SCTLR.C and SCTLR.I: These fields must be zero (as + * required by PSCI specification) + * + * Set remaining SCTLR fields to their architecturally defined + * values. Some fields reset to an IMPLEMENTATION DEFINED value: + * + * SCTLR.TE: Set to zero so that exceptions to an Exception + * Level executing at PL1 are taken to A32 state. + * + * SCTLR.V: Set to zero to select the normal exception vectors + * with base address held in VBAR. + */ + assert(((ep->spsr >> SPSR_E_SHIFT) & SPSR_E_MASK) == + (EP_GET_EE(ep->h.attr) >> EP_EE_SHIFT)); + + sctlr = EP_GET_EE(ep->h.attr) ? SCTLR_EE_BIT : 0; + sctlr |= (SCTLR_RESET_VAL & ~(SCTLR_TE_BIT | SCTLR_V_BIT)); + write_ctx_reg(reg_ctx, CTX_NS_SCTLR, sctlr); + } + + /* + * The target exception level is based on the spsr mode requested. If + * execution is requested to hyp mode, HVC is enabled via SCR.HCE. + */ + if (GET_M32(ep->spsr) == MODE32_hyp) + scr |= SCR_HCE_BIT; + + /* + * Store the initialised values for SCTLR and SCR in the cpu_context. + * The Hyp mode registers are not part of the saved context and are + * set-up in cm_prepare_el3_exit(). + */ + write_ctx_reg(reg_ctx, CTX_SCR, scr); + write_ctx_reg(reg_ctx, CTX_LR, ep->pc); + write_ctx_reg(reg_ctx, CTX_SPSR, ep->spsr); + + /* + * Store the r0-r3 value from the entrypoint into the context + * Use memcpy as we are in control of the layout of the structures + */ + memcpy((void *)reg_ctx, (void *)&ep->args, sizeof(aapcs32_params_t)); +} + +/******************************************************************************* + * The following function initializes the cpu_context for a CPU specified by + * its `cpu_idx` for first use, and sets the initial entrypoint state as + * specified by the entry_point_info structure. + ******************************************************************************/ +void cm_init_context_by_index(unsigned int cpu_idx, + const entry_point_info_t *ep) +{ + cpu_context_t *ctx; + ctx = cm_get_context_by_index(cpu_idx, GET_SECURITY_STATE(ep->h.attr)); + cm_init_context_common(ctx, ep); +} + +/******************************************************************************* + * The following function initializes the cpu_context for the current CPU + * for first use, and sets the initial entrypoint state as specified by the + * entry_point_info structure. + ******************************************************************************/ +void cm_init_my_context(const entry_point_info_t *ep) +{ + cpu_context_t *ctx; + ctx = cm_get_context(GET_SECURITY_STATE(ep->h.attr)); + cm_init_context_common(ctx, ep); +} + +/******************************************************************************* + * Prepare the CPU system registers for first entry into secure or normal world + * + * If execution is requested to hyp mode, HSCTLR is initialized + * If execution is requested to non-secure PL1, and the CPU supports + * HYP mode then HYP mode is disabled by configuring all necessary HYP mode + * registers. + ******************************************************************************/ +void cm_prepare_el3_exit(uint32_t security_state) +{ + uint32_t hsctlr, scr; + cpu_context_t *ctx = cm_get_context(security_state); + + assert(ctx); + + if (security_state == NON_SECURE) { + scr = read_ctx_reg(get_regs_ctx(ctx), CTX_SCR); + if (scr & SCR_HCE_BIT) { + /* Use SCTLR value to initialize HSCTLR */ + hsctlr = read_ctx_reg(get_regs_ctx(ctx), + CTX_NS_SCTLR); + hsctlr |= HSCTLR_RES1; + /* Temporarily set the NS bit to access HSCTLR */ + write_scr(read_scr() | SCR_NS_BIT); + /* + * Make sure the write to SCR is complete so that + * we can access HSCTLR + */ + isb(); + write_hsctlr(hsctlr); + isb(); + + write_scr(read_scr() & ~SCR_NS_BIT); + isb(); + } else if (read_id_pfr1() & + (ID_PFR1_VIRTEXT_MASK << ID_PFR1_VIRTEXT_SHIFT)) { + /* + * Set the NS bit to access NS copies of certain banked + * registers + */ + write_scr(read_scr() | SCR_NS_BIT); + isb(); + + /* + * Hyp / PL2 present but unused, need to disable safely. + * HSCTLR can be ignored in this case. + * + * Set HCR to its architectural reset value so that + * Non-secure operations do not trap to Hyp mode. + */ + write_hcr(HCR_RESET_VAL); + + /* + * Set HCPTR to its architectural reset value so that + * Non-secure access from EL1 or EL0 to trace and to + * Advanced SIMD and floating point functionality does + * not trap to Hyp mode. + */ + write_hcptr(HCPTR_RESET_VAL); + + /* + * Initialise CNTHCTL. All fields are architecturally + * UNKNOWN on reset and are set to zero except for + * field(s) listed below. + * + * CNTHCTL.PL1PCEN: Disable traps to Hyp mode of + * Non-secure EL0 and EL1 accessed to the physical + * timer registers. + * + * CNTHCTL.PL1PCTEN: Disable traps to Hyp mode of + * Non-secure EL0 and EL1 accessed to the physical + * counter registers. + */ + write_cnthctl(CNTHCTL_RESET_VAL | + PL1PCEN_BIT | PL1PCTEN_BIT); + + /* + * Initialise CNTVOFF to zero as it resets to an + * IMPLEMENTATION DEFINED value. + */ + write64_cntvoff(0); + + /* + * Set VPIDR and VMPIDR to match MIDR_EL1 and MPIDR + * respectively. + */ + write_vpidr(read_midr()); + write_vmpidr(read_mpidr()); + + /* + * Initialise VTTBR, setting all fields rather than + * relying on the hw. Some fields are architecturally + * UNKNOWN at reset. + * + * VTTBR.VMID: Set to zero which is the architecturally + * defined reset value. Even though EL1&0 stage 2 + * address translation is disabled, cache maintenance + * operations depend on the VMID. + * + * VTTBR.BADDR: Set to zero as EL1&0 stage 2 address + * translation is disabled. + */ + write64_vttbr(VTTBR_RESET_VAL & + ~((VTTBR_VMID_MASK << VTTBR_VMID_SHIFT) + | (VTTBR_BADDR_MASK << VTTBR_BADDR_SHIFT))); + + /* + * Initialise HDCR, setting all the fields rather than + * relying on hw. + * + * HDCR.HPMN: Set to value of PMCR.N which is the + * architecturally-defined reset value. + */ + write_hdcr(HDCR_RESET_VAL | + ((read_pmcr() & PMCR_N_BITS) >> PMCR_N_SHIFT)); + + /* + * Set HSTR to its architectural reset value so that + * access to system registers in the cproc=1111 + * encoding space do not trap to Hyp mode. + */ + write_hstr(HSTR_RESET_VAL); + /* + * Set CNTHP_CTL to its architectural reset value to + * disable the EL2 physical timer and prevent timer + * interrupts. Some fields are architecturally UNKNOWN + * on reset and are set to zero. + */ + write_cnthp_ctl(CNTHP_CTL_RESET_VAL); + isb(); + + write_scr(read_scr() & ~SCR_NS_BIT); + isb(); + } + } +} |