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Diffstat (limited to 'bl31/ehf.c')
-rw-r--r-- | bl31/ehf.c | 340 |
1 files changed, 340 insertions, 0 deletions
diff --git a/bl31/ehf.c b/bl31/ehf.c new file mode 100644 index 00000000..9758d1aa --- /dev/null +++ b/bl31/ehf.c @@ -0,0 +1,340 @@ +/* + * Copyright (c) 2017, ARM Limited and Contributors. All rights reserved. + * + * SPDX-License-Identifier: BSD-3-Clause + */ + +/* + * Exception handlers at EL3, their priority levels, and management. + */ + +#include <assert.h> +#include <cpu_data.h> +#include <debug.h> +#include <ehf.h> +#include <interrupt_mgmt.h> +#include <platform.h> + +/* Output EHF logs as verbose */ +#define EHF_LOG(...) VERBOSE("EHF: " __VA_ARGS__) + +#define EHF_INVALID_IDX (-1) + +/* For a valid handler, return the actual function pointer; otherwise, 0. */ +#define RAW_HANDLER(h) \ + ((ehf_handler_t) ((h & _EHF_PRI_VALID) ? (h & ~_EHF_PRI_VALID) : 0)) + +#define PRI_BIT(idx) (((ehf_pri_bits_t) 1) << idx) + +/* + * Convert index into secure priority using the platform-defined priority bits + * field. + */ +#define IDX_TO_PRI(idx) \ + ((idx << (7 - exception_data.pri_bits)) & 0x7f) + +/* Check whether a given index is valid */ +#define IS_IDX_VALID(idx) \ + ((exception_data.ehf_priorities[idx].ehf_handler & _EHF_PRI_VALID) != 0) + +/* Returns whether given priority is in secure priority range */ +#define IS_PRI_SECURE(pri) ((pri & 0x80) == 0) + +/* To be defined by the platform */ +extern const ehf_priorities_t exception_data; + +/* Translate priority to the index in the priority array */ +static int pri_to_idx(unsigned int priority) +{ + int idx; + + idx = EHF_PRI_TO_IDX(priority, exception_data.pri_bits); + assert((idx >= 0) && (idx < exception_data.num_priorities)); + assert(IS_IDX_VALID(idx)); + + return idx; +} + +/* Return whether there are outstanding priority activation */ +static int has_valid_pri_activations(pe_exc_data_t *pe_data) +{ + return pe_data->active_pri_bits != 0; +} + +static pe_exc_data_t *this_cpu_data(void) +{ + return &get_cpu_data(ehf_data); +} + +/* + * Return the current priority index of this CPU. If no priority is active, + * return EHF_INVALID_IDX. + */ +static int get_pe_highest_active_idx(pe_exc_data_t *pe_data) +{ + if (!has_valid_pri_activations(pe_data)) + return EHF_INVALID_IDX; + + /* Current priority is the right-most bit */ + return __builtin_ctz(pe_data->active_pri_bits); +} + +/* + * Mark priority active by setting the corresponding bit in active_pri_bits and + * programming the priority mask. + * + * This API is to be used as part of delegating to lower ELs other than for + * interrupts; e.g. while handling synchronous exceptions. + * + * This API is expected to be invoked before restoring context (Secure or + * Non-secure) in preparation for the respective dispatch. + */ +void ehf_activate_priority(unsigned int priority) +{ + int idx, cur_pri_idx; + unsigned int old_mask, run_pri; + pe_exc_data_t *pe_data = this_cpu_data(); + + /* + * Query interrupt controller for the running priority, or idle priority + * if no interrupts are being handled. The requested priority must be + * less (higher priority) than the active running priority. + */ + run_pri = plat_ic_get_running_priority(); + if (priority >= run_pri) { + ERROR("Running priority higher (0x%x) than requested (0x%x)\n", + run_pri, priority); + panic(); + } + + /* + * If there were priority activations already, the requested priority + * must be less (higher priority) than the current highest priority + * activation so far. + */ + cur_pri_idx = get_pe_highest_active_idx(pe_data); + idx = pri_to_idx(priority); + if ((cur_pri_idx != EHF_INVALID_IDX) && (idx >= cur_pri_idx)) { + ERROR("Activation priority mismatch: req=0x%x current=0x%x\n", + priority, IDX_TO_PRI(cur_pri_idx)); + panic(); + } + + /* Set the bit corresponding to the requested priority */ + pe_data->active_pri_bits |= PRI_BIT(idx); + + /* + * Program priority mask for the activated level. Check that the new + * priority mask is setting a higher priority level than the existing + * mask. + */ + old_mask = plat_ic_set_priority_mask(priority); + if (priority >= old_mask) { + ERROR("Requested priority (0x%x) lower than Priority Mask (0x%x)\n", + priority, old_mask); + panic(); + } + + /* + * If this is the first activation, save the priority mask. This will be + * restored after the last deactivation. + */ + if (cur_pri_idx == EHF_INVALID_IDX) + pe_data->init_pri_mask = old_mask; + + EHF_LOG("activate prio=%d\n", get_pe_highest_active_idx(pe_data)); +} + +/* + * Mark priority inactive by clearing the corresponding bit in active_pri_bits, + * and programming the priority mask. + * + * This API is expected to be used as part of delegating to to lower ELs other + * than for interrupts; e.g. while handling synchronous exceptions. + * + * This API is expected to be invoked after saving context (Secure or + * Non-secure), having concluded the respective dispatch. + */ +void ehf_deactivate_priority(unsigned int priority) +{ + int idx, cur_pri_idx; + pe_exc_data_t *pe_data = this_cpu_data(); + unsigned int old_mask, run_pri; + + /* + * Query interrupt controller for the running priority, or idle priority + * if no interrupts are being handled. The requested priority must be + * less (higher priority) than the active running priority. + */ + run_pri = plat_ic_get_running_priority(); + if (priority >= run_pri) { + ERROR("Running priority higher (0x%x) than requested (0x%x)\n", + run_pri, priority); + panic(); + } + + /* + * Deactivation is allowed only when there are priority activations, and + * the deactivation priority level must match the current activated + * priority. + */ + cur_pri_idx = get_pe_highest_active_idx(pe_data); + idx = pri_to_idx(priority); + if ((cur_pri_idx == EHF_INVALID_IDX) || (idx != cur_pri_idx)) { + ERROR("Deactivation priority mismatch: req=0x%x current=0x%x\n", + priority, IDX_TO_PRI(cur_pri_idx)); + panic(); + } + + /* Clear bit corresponding to highest priority */ + pe_data->active_pri_bits &= (pe_data->active_pri_bits - 1); + + /* + * Restore priority mask corresponding to the next priority, or the + * one stashed earlier if there are no more to deactivate. + */ + idx = get_pe_highest_active_idx(pe_data); + if (idx == EHF_INVALID_IDX) + old_mask = plat_ic_set_priority_mask(pe_data->init_pri_mask); + else + old_mask = plat_ic_set_priority_mask(priority); + + if (old_mask >= priority) { + ERROR("Deactivation priority (0x%x) lower than Priority Mask (0x%x)\n", + priority, old_mask); + panic(); + } + + EHF_LOG("deactivate prio=%d\n", get_pe_highest_active_idx(pe_data)); +} + +/* + * Top-level EL3 interrupt handler. + */ +static uint64_t ehf_el3_interrupt_handler(uint32_t id, uint32_t flags, + void *handle, void *cookie) +{ + int pri, idx, intr, intr_raw, ret = 0; + ehf_handler_t handler; + + /* + * Top-level interrupt type handler from Interrupt Management Framework + * doesn't acknowledge the interrupt; so the interrupt ID must be + * invalid. + */ + assert(id == INTR_ID_UNAVAILABLE); + + /* + * Acknowledge interrupt. Proceed with handling only for valid interrupt + * IDs. This situation may arise because of Interrupt Management + * Framework identifying an EL3 interrupt, but before it's been + * acknowledged here, the interrupt was either deasserted, or there was + * a higher-priority interrupt of another type. + */ + intr_raw = plat_ic_acknowledge_interrupt(); + intr = plat_ic_get_interrupt_id(intr_raw); + if (intr == INTR_ID_UNAVAILABLE) + return 0; + + /* Having acknowledged the interrupt, get the running priority */ + pri = plat_ic_get_running_priority(); + + /* Check EL3 interrupt priority is in secure range */ + assert(IS_PRI_SECURE(pri)); + + /* + * Translate the priority to a descriptor index. We do this by masking + * and shifting the running priority value (platform-supplied). + */ + idx = pri_to_idx(pri); + + /* Validate priority */ + assert(pri == IDX_TO_PRI(idx)); + + handler = RAW_HANDLER(exception_data.ehf_priorities[idx].ehf_handler); + if (!handler) { + ERROR("No EL3 exception handler for priority 0x%x\n", + IDX_TO_PRI(idx)); + panic(); + } + + /* + * Call registered handler. Pass the raw interrupt value to registered + * handlers. + */ + ret = handler(intr_raw, flags, handle, cookie); + + return ret; +} + +/* + * Initialize the EL3 exception handling. + */ +void ehf_init(void) +{ + unsigned int flags = 0; + int ret __unused; + + /* Ensure EL3 interrupts are supported */ + assert(plat_ic_has_interrupt_type(INTR_TYPE_EL3)); + + /* + * Make sure that priority water mark has enough bits to represent the + * whole priority array. + */ + assert(exception_data.num_priorities <= (sizeof(ehf_pri_bits_t) * 8)); + + assert(exception_data.ehf_priorities); + + /* + * Bit 7 of GIC priority must be 0 for secure interrupts. This means + * platforms must use at least 1 of the remaining 7 bits. + */ + assert((exception_data.pri_bits >= 1) || (exception_data.pri_bits < 8)); + + /* Route EL3 interrupts when in Secure and Non-secure. */ + set_interrupt_rm_flag(flags, NON_SECURE); + set_interrupt_rm_flag(flags, SECURE); + + /* Register handler for EL3 interrupts */ + ret = register_interrupt_type_handler(INTR_TYPE_EL3, + ehf_el3_interrupt_handler, flags); + assert(ret == 0); +} + +/* + * Register a handler at the supplied priority. Registration is allowed only if + * a handler hasn't been registered before, or one wasn't provided at build + * time. The priority for which the handler is being registered must also accord + * with the platform-supplied data. + */ +void ehf_register_priority_handler(unsigned int pri, ehf_handler_t handler) +{ + int idx; + + /* Sanity check for handler */ + assert(handler != NULL); + + /* Handler ought to be 4-byte aligned */ + assert((((uintptr_t) handler) & 3) == 0); + + /* Ensure we register for valid priority */ + idx = pri_to_idx(pri); + assert(idx < exception_data.num_priorities); + assert(IDX_TO_PRI(idx) == pri); + + /* Return failure if a handler was already registered */ + if (exception_data.ehf_priorities[idx].ehf_handler != _EHF_NO_HANDLER) { + ERROR("Handler already registered for priority 0x%x\n", pri); + panic(); + } + + /* + * Install handler, and retain the valid bit. We assume that the handler + * is 4-byte aligned, which is usually the case. + */ + exception_data.ehf_priorities[idx].ehf_handler = + (((uintptr_t) handler) | _EHF_PRI_VALID); + + EHF_LOG("register pri=0x%x handler=%p\n", pri, handler); +} |