/* * Copyright (c) 2013-2014, ARM Limited and Contributors. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are met: * * Redistributions of source code must retain the above copyright notice, this * list of conditions and the following disclaimer. * * Redistributions in binary form must reproduce the above copyright notice, * this list of conditions and the following disclaimer in the documentation * and/or other materials provided with the distribution. * * Neither the name of ARM nor the names of its contributors may be used * to endorse or promote products derived from this software without specific * prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. */ #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 */ } /******************************************************************************* * This function returns a pointer to the most recent 'cpu_context' structure * for the CPU identified by MPIDR that was set as the context for the specified * security state. NULL is returned if no such structure has been specified. ******************************************************************************/ void *cm_get_context_by_mpidr(uint64_t mpidr, uint32_t security_state) { assert(sec_state_is_valid(security_state)); return get_cpu_data_by_mpidr(mpidr, cpu_context[security_state]); } /******************************************************************************* * This function sets the pointer to the current 'cpu_context' structure for the * specified security state for the CPU identified by MPIDR ******************************************************************************/ void cm_set_context_by_mpidr(uint64_t mpidr, void *context, uint32_t security_state) { assert(sec_state_is_valid(security_state)); set_cpu_data_by_mpidr(mpidr, cpu_context[security_state], context); } /******************************************************************************* * 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 ******************************************************************************/ static inline void cm_set_next_context(void *context) { #if DEBUG uint64_t sp_mode; /* * Check that this function is called with SP_EL0 as the stack * pointer */ __asm__ volatile("mrs %0, SPSel\n" : "=r" (sp_mode)); assert(sp_mode == MODE_SP_EL0); #endif __asm__ volatile("msr spsel, #1\n" "mov sp, %0\n" "msr spsel, #0\n" : : "r" (context)); } /******************************************************************************* * The following function initializes a cpu_context for the current CPU 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 excution 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(). ******************************************************************************/ void cm_init_context(uint64_t mpidr, const entry_point_info_t *ep) { uint32_t security_state; cpu_context_t *ctx; uint32_t scr_el3; el3_state_t *state; gp_regs_t *gp_regs; unsigned long sctlr_elx; security_state = GET_SECURITY_STATE(ep->h.attr); ctx = cm_get_context_by_mpidr(mpidr, security_state); assert(ctx); /* Clear any residual register values from the context */ memset(ctx, 0, sizeof(*ctx)); /* * Base the context SCR on the current value, adjust for entry point * specific requirements and set trap bits from the IMF * TODO: provide the base/global SCR bits using another mechanism? */ scr_el3 = read_scr(); scr_el3 &= ~(SCR_NS_BIT | SCR_RW_BIT | SCR_FIQ_BIT | SCR_IRQ_BIT | SCR_ST_BIT | SCR_HCE_BIT); if (security_state != SECURE) scr_el3 |= SCR_NS_BIT; if (GET_RW(ep->spsr) == MODE_RW_64) scr_el3 |= SCR_RW_BIT; if (EP_GET_ST(ep->h.attr)) scr_el3 |= SCR_ST_BIT; scr_el3 |= get_scr_el3_from_routing_model(security_state); /* * Set up SCTLR_ELx for the target exception level: * EE bit is taken from the entrpoint attributes * M, C and I bits must be zero (as required by PSCI specification) * * The target exception level is based on the spsr mode requested. * If execution is requested to EL2 or hyp mode, HVC is enabled * via SCR_EL3.HCE. * * Always compute the SCTLR_EL1 value and save in the cpu_context * - the EL2 registers are set up by cm_preapre_ns_entry() as they * are not part of the stored cpu_context * * TODO: In debug builds the spsr should be validated and checked * against the CPU support, security state, endianess and pc */ 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 sctlr_elx |= SCTLR_AARCH32_EL1_RES1; write_ctx_reg(get_sysregs_ctx(ctx), CTX_SCTLR_EL1, sctlr_elx); 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; } /* 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)); } /******************************************************************************* * 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, cptr_el2; cpu_context_t *ctx = cm_get_context(security_state); 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 (read_id_aa64pfr0_el1() & (ID_AA64PFR0_ELX_MASK << ID_AA64PFR0_EL2_SHIFT)) { /* EL2 present but unused, need to disable safely */ /* HCR_EL2 = 0, except RW bit set to match SCR_EL3 */ write_hcr_el2((scr_el3 & SCR_RW_BIT) ? HCR_RW_BIT : 0); /* SCTLR_EL2 : can be ignored when bypassing */ /* CPTR_EL2 : disable all traps TCPAC, TTA, TFP */ cptr_el2 = read_cptr_el2(); cptr_el2 &= ~(TCPAC_BIT | TTA_BIT | TFP_BIT); write_cptr_el2(cptr_el2); /* Enable EL1 access to timer */ write_cnthctl_el2(EL1PCEN_BIT | EL1PCTEN_BIT); /* Set VPIDR, VMPIDR to match MIDR, MPIDR */ write_vpidr_el2(read_midr_el1()); write_vmpidr_el2(read_mpidr_el1()); } } el1_sysregs_context_restore(get_sysregs_ctx(ctx)); cm_set_next_context(ctx); } /******************************************************************************* * 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)); } 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)); } /******************************************************************************* * 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, uint64_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, uint64_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); }