| /* |
| * Copyright 2017, Data61 |
| * Commonwealth Scientific and Industrial Research Organisation (CSIRO) |
| * ABN 41 687 119 230. |
| * |
| * This software may be distributed and modified according to the terms of |
| * the BSD 2-Clause license. Note that NO WARRANTY is provided. |
| * See "LICENSE_BSD2.txt" for details. |
| * |
| * @TAG(DATA61_BSD) |
| */ |
| |
| #pragma once |
| |
| #include <autoconf.h> |
| #include <assert.h> |
| #include <sel4/sel4.h> |
| #include <vka/vka.h> |
| #include <vka/object.h> |
| #include <stddef.h> |
| #include <sync/sem-bare.h> |
| |
| typedef struct { |
| vka_object_t ep; |
| volatile int value; |
| } sync_sem_t; |
| |
| /* Initialise an unmanaged semaphore with an endpoint object |
| * @param sem A semaphore object to be initialised. |
| * @param notification An endpoint to use for the lock. |
| * @param value An initial value for the semaphore. |
| * @return 0 on success, an error code on failure. */ |
| static inline int sync_sem_init(sync_sem_t *sem, seL4_CPtr ep, int value) |
| { |
| if (sem == NULL) { |
| ZF_LOGE("Semaphore passed to sync_sem_init was NULL"); |
| return -1; |
| } |
| #ifdef CONFIG_DEBUG_BUILD |
| /* Check the cap actually is an EP. */ |
| assert(seL4_DebugCapIdentify(ep) == 4); |
| #endif |
| |
| sem->ep.cptr = ep; |
| sem->value = value; |
| return 0; |
| } |
| |
| /* Wait on a semaphore |
| * @param sem An initialised semaphore to acquire. |
| * @return 0 on success, an error code on failure. */ |
| static inline int sync_sem_wait(sync_sem_t *sem) |
| { |
| if (sem == NULL) { |
| ZF_LOGE("Semaphore passed to sync_sem_wait was NULL"); |
| return -1; |
| } |
| return sync_sem_bare_wait(sem->ep.cptr, &sem->value); |
| } |
| |
| /* Try to wait on the semaphore without waiting on the endpoint |
| * i.e. check the semaphore value in a loop |
| * @param sem An initialised semaphore to acquire. |
| * @return 0 on success, an error code on failure. */ |
| static inline int sync_sem_trywait(sync_sem_t *sem) |
| { |
| if (sem == NULL) { |
| ZF_LOGE("Semaphore passed to sync_sem_trywait was NULL"); |
| return -1; |
| } |
| return sync_sem_bare_trywait(sem->ep.cptr, &sem->value); |
| } |
| |
| /* Signal a binary semaphore |
| * @param sem An initialised semaphore to release. |
| * @return 0 on success, an error code on failure. */ |
| static inline int sync_sem_post(sync_sem_t *sem) |
| { |
| if (sem == NULL) { |
| ZF_LOGE("Semaphore passed to sync_sem_post was NULL"); |
| return -1; |
| } |
| return sync_sem_bare_post(sem->ep.cptr, &sem->value); |
| } |
| |
| /* Allocate and initialise a managed semaphore |
| * @param vka A VKA instance used to allocate an endpoint. |
| * @param sem A semaphore object to initialise. |
| * @param value An initial value for the semaphore. |
| * @return 0 on success, an error code on failure. */ |
| static inline int sync_sem_new(vka_t *vka, sync_sem_t *sem, int value) |
| { |
| if (sem == NULL) { |
| ZF_LOGE("Semaphore passed to sync_sem_new was NULL"); |
| return -1; |
| } |
| int error = vka_alloc_endpoint(vka, &(sem->ep)); |
| |
| if (error != 0) { |
| return error; |
| } else { |
| return sync_sem_init(sem, sem->ep.cptr, value); |
| } |
| } |
| |
| /* Deallocate a managed semaphore (do not use with sync_sem_init) |
| * @param vka A VKA instance used to deallocate the endpoint. |
| * @param sem A semaphore object initialised by sync_sem_new. |
| * @return 0 on success, an error code on failure. */ |
| static inline int sync_sem_destroy(vka_t *vka, sync_sem_t *sem) |
| { |
| if (sem == NULL) { |
| ZF_LOGE("Semaphore passed to sync_sem_destroy was NULL"); |
| return -1; |
| } |
| vka_free_object(vka, &(sem->ep)); |
| return 0; |
| } |
| |