/* * Copyright (c) 2013-2017, ARM Limited and Contributors. All rights reserved. * * SPDX-License-Identifier: BSD-3-Clause */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include /******************************************************************************* * 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 dispatcher service 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. * Lastly, this library provides the api to make SP_EL3 point to the cpu context * which will used for programming an entry into a lower EL. The same context * will used to save state upon exception entry from that EL. ******************************************************************************/ void cm_init(void) { /* * The context management library has only global data to intialize, 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 endianess 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_el3, pmcr_el0; el3_state_t *state; gp_regs_t *gp_regs; unsigned long sctlr_elx; assert(ctx); security_state = GET_SECURITY_STATE(ep->h.attr); /* Clear any residual register values from the context */ zeromem(ctx, sizeof(*ctx)); /* * SCR_EL3 was initialised during reset sequence in macro * el3_arch_init_common. This code modifies the SCR_EL3 fields that * affect the next EL. * * The following fields are initially set to zero and then updated to * the required value depending on the state of the SPSR_EL3 and the * Security state and entrypoint attributes of the next EL. */ scr_el3 = read_scr(); scr_el3 &= ~(SCR_NS_BIT | SCR_RW_BIT | SCR_FIQ_BIT | SCR_IRQ_BIT | SCR_ST_BIT | SCR_HCE_BIT); /* * SCR_NS: Set the security state of the next EL. */ if (security_state != SECURE) scr_el3 |= SCR_NS_BIT; /* * SCR_EL3.RW: Set the execution state, AArch32 or AArch64, for next * Exception level as specified by SPSR. */ if (GET_RW(ep->spsr) == MODE_RW_64) scr_el3 |= SCR_RW_BIT; /* * SCR_EL3.ST: Traps Secure EL1 accesses to the Counter-timer Physical * Secure timer registers to EL3, from AArch64 state only, if specified * by the entrypoint attributes. */ if (EP_GET_ST(ep->h.attr)) scr_el3 |= SCR_ST_BIT; #ifndef HANDLE_EA_EL3_FIRST /* * SCR_EL3.EA: Do not route External Abort and SError Interrupt External * to EL3 when executing at a lower EL. When executing at EL3, External * Aborts are taken to EL3. */ scr_el3 &= ~SCR_EA_BIT; #endif #ifdef IMAGE_BL31 /* * SCR_EL3.IRQ, SCR_EL3.FIQ: Enable the physical FIQ and IRQ rounting as * indicated by the interrupt routing model for BL31. */ scr_el3 |= get_scr_el3_from_routing_model(security_state); #endif /* * SCR_EL3.HCE: Enable HVC instructions if next execution state is * AArch64 and next EL is EL2, or if next execution state is AArch32 and * next mode is Hyp. */ if ((GET_RW(ep->spsr) == MODE_RW_64 && GET_EL(ep->spsr) == MODE_EL2) || (GET_RW(ep->spsr) != MODE_RW_64 && GET_M32(ep->spsr) == MODE32_hyp)) { scr_el3 |= SCR_HCE_BIT; } /* * Initialise SCTLR_EL1 to the reset value corresponding to the target * execution state setting all fields rather than relying of the hw. * Some fields have architecturally UNKNOWN reset values and these are * set to zero. * * 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) */ sctlr_elx = EP_GET_EE(ep->h.attr) ? SCTLR_EE_BIT : 0; if (GET_RW(ep->spsr) == MODE_RW_64) sctlr_elx |= SCTLR_EL1_RES1; else { /* * If the target execution state is AArch32 then the following * fields need to be set. * * SCTRL_EL1.nTWE: Set to one so that EL0 execution of WFE * instructions are not trapped to EL1. * * SCTLR_EL1.nTWI: Set to one so that EL0 execution of WFI * instructions are not trapped to EL1. * * SCTLR_EL1.CP15BEN: Set to one to enable EL0 execution of the * CP15DMB, CP15DSB, and CP15ISB instructions. */ sctlr_elx |= SCTLR_AARCH32_EL1_RES1 | SCTLR_CP15BEN_BIT | SCTLR_NTWI_BIT | SCTLR_NTWE_BIT; } /* * Store the initialised SCTLR_EL1 value in the cpu_context - SCTLR_EL2 * and other EL2 registers are set up by cm_preapre_ns_entry() as they * are not part of the stored cpu_context. */ write_ctx_reg(get_sysregs_ctx(ctx), CTX_SCTLR_EL1, sctlr_elx); if (security_state == SECURE) { /* * Initialise PMCR_EL0 for secure context only, setting all * fields rather than relying on hw. Some fields are * architecturally UNKNOWN on reset. * * PMCR_EL0.LC: Set to one so that cycle counter overflow, that * is recorded in PMOVSCLR_EL0[31], occurs on the increment * that changes PMCCNTR_EL0[63] from 1 to 0. * * PMCR_EL0.DP: Set to one so that the cycle counter, * PMCCNTR_EL0 does not count when event counting is prohibited. * * PMCR_EL0.X: Set to zero to disable export of events. * * PMCR_EL0.D: Set to zero so that, when enabled, PMCCNTR_EL0 * counts on every clock cycle. */ pmcr_el0 = ((PMCR_EL0_RESET_VAL | PMCR_EL0_LC_BIT | PMCR_EL0_DP_BIT) & ~(PMCR_EL0_X_BIT | PMCR_EL0_D_BIT)); write_ctx_reg(get_sysregs_ctx(ctx), CTX_PMCR_EL0, pmcr_el0); } /* Populate EL3 state so that we've the right context before doing ERET */ state = get_el3state_ctx(ctx); write_ctx_reg(state, CTX_SCR_EL3, scr_el3); write_ctx_reg(state, CTX_ELR_EL3, ep->pc); write_ctx_reg(state, CTX_SPSR_EL3, ep->spsr); /* * Store the X0-X7 value from the entrypoint into the context * Use memcpy as we are in control of the layout of the structures */ gp_regs = get_gpregs_ctx(ctx); memcpy(gp_regs, (void *)&ep->args, sizeof(aapcs64_params_t)); } /******************************************************************************* * Enable architecture extensions on first entry to Non-secure world. * When EL2 is implemented but unused `el2_unused` is non-zero, otherwise * it is zero. ******************************************************************************/ static void enable_extensions_nonsecure(int el2_unused) { #if IMAGE_BL31 #if ENABLE_SPE_FOR_LOWER_ELS spe_enable(el2_unused); #endif #endif } /******************************************************************************* * 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 EL2 or hyp mode, SCTLR_EL2 is initialized * If execution is requested to non-secure EL1 or svc mode, and the CPU supports * EL2 then EL2 is disabled by configuring all necessary EL2 registers. * For all entries, the EL1 registers are initialized from the cpu_context ******************************************************************************/ void cm_prepare_el3_exit(uint32_t security_state) { uint32_t sctlr_elx, scr_el3, mdcr_el2; cpu_context_t *ctx = cm_get_context(security_state); int el2_unused = 0; assert(ctx); if (security_state == NON_SECURE) { scr_el3 = read_ctx_reg(get_el3state_ctx(ctx), CTX_SCR_EL3); if (scr_el3 & SCR_HCE_BIT) { /* Use SCTLR_EL1.EE value to initialise sctlr_el2 */ sctlr_elx = read_ctx_reg(get_sysregs_ctx(ctx), CTX_SCTLR_EL1); sctlr_elx &= SCTLR_EE_BIT; sctlr_elx |= SCTLR_EL2_RES1; write_sctlr_el2(sctlr_elx); } else if (EL_IMPLEMENTED(2)) { el2_unused = 1; /* * EL2 present but unused, need to disable safely. * SCTLR_EL2 can be ignored in this case. * * Initialise all fields in HCR_EL2, except HCR_EL2.RW, * to zero so that Non-secure operations do not trap to * EL2. * * HCR_EL2.RW: Set this field to match SCR_EL3.RW */ write_hcr_el2((scr_el3 & SCR_RW_BIT) ? HCR_RW_BIT : 0); /* * Initialise CPTR_EL2 setting all fields rather than * relying on the hw. All fields have architecturally * UNKNOWN reset values. * * CPTR_EL2.TCPAC: Set to zero so that Non-secure EL1 * accesses to the CPACR_EL1 or CPACR from both * Execution states do not trap to EL2. * * CPTR_EL2.TTA: Set to zero so that Non-secure System * register accesses to the trace registers from both * Execution states do not trap to EL2. * * CPTR_EL2.TFP: Set to zero so that Non-secure accesses * to SIMD and floating-point functionality from both * Execution states do not trap to EL2. */ write_cptr_el2(CPTR_EL2_RESET_VAL & ~(CPTR_EL2_TCPAC_BIT | CPTR_EL2_TTA_BIT | CPTR_EL2_TFP_BIT)); /* * Initiliase 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 * Hyp mode of Non-secure EL0 and EL1 accesses to the * physical timer registers. * * CNTHCTL_EL2.EL1PCTEN: Set to one to disable traps to * Hyp mode of Non-secure EL0 and EL1 accesses to the * physical counter registers. */ write_cnthctl_el2(CNTHCTL_RESET_VAL | EL1PCEN_BIT | EL1PCTEN_BIT); /* * Initialise CNTVOFF_EL2 to zero as it resets to an * architecturally UNKNOWN value. */ write_cntvoff_el2(0); /* * Set VPIDR_EL2 and VMPIDR_EL2 to match MIDR_EL1 and * MPIDR_EL1 respectively. */ write_vpidr_el2(read_midr_el1()); write_vmpidr_el2(read_mpidr_el1()); /* * Initialise VTTBR_EL2. All fields are architecturally * UNKNOWN on reset. * * VTTBR_EL2.VMID: Set to zero. Even though EL1&0 stage * 2 address translation is disabled, cache maintenance * operations depend on the VMID. * * VTTBR_EL2.BADDR: Set to zero as EL1&0 stage 2 address * translation is disabled. */ write_vttbr_el2(VTTBR_RESET_VAL & ~((VTTBR_VMID_MASK << VTTBR_VMID_SHIFT) | (VTTBR_BADDR_MASK << VTTBR_BADDR_SHIFT))); /* * Initialise MDCR_EL2, setting all fields rather than * relying on hw. Some fields are architecturally * UNKNOWN on reset. * * MDCR_EL2.TDRA: Set to zero so that Non-secure EL0 and * EL1 System register accesses to the Debug ROM * registers are not trapped to EL2. * * MDCR_EL2.TDOSA: Set to zero so that Non-secure EL1 * System register accesses to the powerdown debug * registers are not trapped to EL2. * * MDCR_EL2.TDA: Set to zero so that System register * accesses to the debug registers do not trap to EL2. * * MDCR_EL2.TDE: Set to zero so that debug exceptions * are not routed to EL2. * * MDCR_EL2.HPME: Set to zero to disable EL2 Performance * Monitors. * * MDCR_EL2.TPM: Set to zero so that Non-secure EL0 and * EL1 accesses to all Performance Monitors registers * are not trapped to EL2. * * MDCR_EL2.TPMCR: Set to zero so that Non-secure EL0 * and EL1 accesses to the PMCR_EL0 or PMCR are not * trapped to EL2. * * MDCR_EL2.HPMN: Set to value of PMCR_EL0.N which is the * architecturally-defined reset value. */ mdcr_el2 = ((MDCR_EL2_RESET_VAL | ((read_pmcr_el0() & PMCR_EL0_N_BITS) >> PMCR_EL0_N_SHIFT)) & ~(MDCR_EL2_TDRA_BIT | MDCR_EL2_TDOSA_BIT | MDCR_EL2_TDA_BIT | MDCR_EL2_TDE_BIT | MDCR_EL2_HPME_BIT | MDCR_EL2_TPM_BIT | MDCR_EL2_TPMCR_BIT)); write_mdcr_el2(mdcr_el2); /* * Initialise HSTR_EL2. All fields are architecturally * UNKNOWN on reset. * * HSTR_EL2.T: Set all these fields to zero so that * Non-secure EL0 or EL1 accesses to System registers * do not trap to EL2. */ write_hstr_el2(HSTR_EL2_RESET_VAL & ~(HSTR_EL2_T_MASK)); /* * Initialise CNTHP_CTL_EL2. All fields are * architecturally UNKNOWN on reset. * * CNTHP_CTL_EL2:ENABLE: Set to zero to disable the EL2 * physical timer and prevent timer interrupts. */ write_cnthp_ctl_el2(CNTHP_CTL_RESET_VAL & ~(CNTHP_CTL_ENABLE_BIT)); } enable_extensions_nonsecure(el2_unused); } cm_el1_sysregs_context_restore(security_state); cm_set_next_eret_context(security_state); } /******************************************************************************* * The next four functions are used by runtime services to save and restore * EL1 context on the 'cpu_context' structure for the specified security * state. ******************************************************************************/ void cm_el1_sysregs_context_save(uint32_t security_state) { cpu_context_t *ctx; ctx = cm_get_context(security_state); assert(ctx); el1_sysregs_context_save(get_sysregs_ctx(ctx)); #if IMAGE_BL31 if (security_state == SECURE) PUBLISH_EVENT(cm_exited_secure_world); else PUBLISH_EVENT(cm_exited_normal_world); #endif } void cm_el1_sysregs_context_restore(uint32_t security_state) { cpu_context_t *ctx; ctx = cm_get_context(security_state); assert(ctx); el1_sysregs_context_restore(get_sysregs_ctx(ctx)); #if IMAGE_BL31 if (security_state == SECURE) PUBLISH_EVENT(cm_entering_secure_world); else PUBLISH_EVENT(cm_entering_normal_world); #endif } /******************************************************************************* * This function populates ELR_EL3 member of 'cpu_context' pertaining to the * given security state with the given entrypoint ******************************************************************************/ void cm_set_elr_el3(uint32_t security_state, uintptr_t entrypoint) { cpu_context_t *ctx; el3_state_t *state; ctx = cm_get_context(security_state); assert(ctx); /* Populate EL3 state so that ERET jumps to the correct entry */ state = get_el3state_ctx(ctx); write_ctx_reg(state, CTX_ELR_EL3, entrypoint); } /******************************************************************************* * This function populates ELR_EL3 and SPSR_EL3 members of 'cpu_context' * pertaining to the given security state ******************************************************************************/ void cm_set_elr_spsr_el3(uint32_t security_state, uintptr_t entrypoint, uint32_t spsr) { cpu_context_t *ctx; el3_state_t *state; ctx = cm_get_context(security_state); assert(ctx); /* Populate EL3 state so that ERET jumps to the correct entry */ state = get_el3state_ctx(ctx); write_ctx_reg(state, CTX_ELR_EL3, entrypoint); write_ctx_reg(state, CTX_SPSR_EL3, spsr); } /******************************************************************************* * This function updates a single bit in the SCR_EL3 member of the 'cpu_context' * pertaining to the given security state using the value and bit position * specified in the parameters. It preserves all other bits. ******************************************************************************/ void cm_write_scr_el3_bit(uint32_t security_state, uint32_t bit_pos, uint32_t value) { cpu_context_t *ctx; el3_state_t *state; uint32_t scr_el3; ctx = cm_get_context(security_state); assert(ctx); /* Ensure that the bit position is a valid one */ assert((1 << bit_pos) & SCR_VALID_BIT_MASK); /* Ensure that the 'value' is only a bit wide */ assert(value <= 1); /* * Get the SCR_EL3 value from the cpu context, clear the desired bit * and set it to its new value. */ state = get_el3state_ctx(ctx); scr_el3 = read_ctx_reg(state, CTX_SCR_EL3); scr_el3 &= ~(1 << bit_pos); scr_el3 |= value << bit_pos; write_ctx_reg(state, CTX_SCR_EL3, scr_el3); } /******************************************************************************* * This function retrieves SCR_EL3 member of 'cpu_context' pertaining to the * given security state. ******************************************************************************/ uint32_t cm_get_scr_el3(uint32_t security_state) { cpu_context_t *ctx; el3_state_t *state; ctx = cm_get_context(security_state); assert(ctx); /* Populate EL3 state so that ERET jumps to the correct entry */ state = get_el3state_ctx(ctx); return read_ctx_reg(state, CTX_SCR_EL3); } /******************************************************************************* * This function is used to program the context that's used for exception * return. This initializes the SP_EL3 to a pointer to a 'cpu_context' set for * the required security state ******************************************************************************/ void cm_set_next_eret_context(uint32_t security_state) { cpu_context_t *ctx; ctx = cm_get_context(security_state); assert(ctx); cm_set_next_context(ctx); }