/* * Copyright (c) 2006-2021, RT-Thread Development Team * * SPDX-License-Identifier: Apache-2.0 * * Change Logs: * Date Author Notes * 2021-04-27 peterfan Add copyright header. */ /* ===---------- emutls.c - Implements __emutls_get_address ---------------=== * * The LLVM Compiler Infrastructure * * This file is dual licensed under the MIT and the University of Illinois Open * Source Licenses. See LICENSE.TXT for details. * * ===----------------------------------------------------------------------=== */ #include #include #include #include extern int pthread_key_create(pthread_key_t *key, void (*destructor)(void *)); extern int pthread_key_delete(pthread_key_t key); extern void *pthread_getspecific(pthread_key_t key); extern int pthread_setspecific(pthread_key_t key, const void *value); /* Default is not to use posix_memalign, so systems like Android * can use thread local data without heavier POSIX memory allocators. */ #ifndef EMUTLS_USE_POSIX_MEMALIGN #define EMUTLS_USE_POSIX_MEMALIGN 0 #endif /* For every TLS variable xyz, * there is one __emutls_control variable named __emutls_v.xyz. * If xyz has non-zero initial value, __emutls_v.xyz's "value" * will point to __emutls_t.xyz, which has the initial value. */ typedef struct __emutls_control { size_t size; /* size of the object in bytes */ size_t align; /* alignment of the object in bytes */ union { uintptr_t index; /* data[index-1] is the object address */ void *address; /* object address, when in single thread env */ } object; void *value; /* null or non-zero initial value for the object */ } __emutls_control; static __inline void *emutls_memalign_alloc(size_t align, size_t size) { void *base; #if EMUTLS_USE_POSIX_MEMALIGN if (posix_memalign(&base, align, size) != 0) abort(); #else #define EXTRA_ALIGN_PTR_BYTES (align - 1 + sizeof(void *)) char *object; if ((object = (char *)malloc(EXTRA_ALIGN_PTR_BYTES + size)) == NULL) abort(); base = (void *)(((uintptr_t)(object + EXTRA_ALIGN_PTR_BYTES)) & ~(uintptr_t)(align - 1)); ((void **)base)[-1] = object; #endif return base; } static __inline void emutls_memalign_free(void *base) { #if EMUTLS_USE_POSIX_MEMALIGN free(base); #else /* The mallocated address is in ((void**)base)[-1] */ free(((void **)base)[-1]); #endif } /* Emulated TLS objects are always allocated at run-time. */ static __inline void *emutls_allocate_object(__emutls_control *control) { size_t size = control->size; size_t align = control->align; if (align < sizeof(void *)) align = sizeof(void *); /* Make sure that align is power of 2. */ if ((align & (align - 1)) != 0) abort(); void *base = emutls_memalign_alloc(align, size); if (control->value) memcpy(base, control->value, size); else memset(base, 0, size); return base; } static pthread_mutex_t emutls_mutex = PTHREAD_MUTEX_INITIALIZER; static size_t emutls_num_object = 0; /* number of allocated TLS objects */ typedef struct emutls_address_array { uintptr_t size; /* number of elements in the 'data' array */ void *data[]; } emutls_address_array; static pthread_key_t emutls_pthread_key; static void emutls_key_destructor(void *ptr) { emutls_address_array *array = (emutls_address_array *)ptr; uintptr_t i; for (i = 0; i < array->size; ++i) { if (array->data[i]) emutls_memalign_free(array->data[i]); } free(ptr); } static void emutls_init(void) { if (pthread_key_create(&emutls_pthread_key, emutls_key_destructor) != 0) abort(); } /* Returns control->object.index; set index if not allocated yet. */ static __inline uintptr_t emutls_get_index(__emutls_control *control) { uintptr_t index = __atomic_load_n(&control->object.index, __ATOMIC_ACQUIRE); if (!index) { static pthread_once_t once = PTHREAD_ONCE_INIT; pthread_once(&once, emutls_init); pthread_mutex_lock(&emutls_mutex); index = control->object.index; if (!index) { index = ++emutls_num_object; __atomic_store_n(&control->object.index, index, __ATOMIC_RELEASE); } pthread_mutex_unlock(&emutls_mutex); } return index; } /* Updates newly allocated thread local emutls_address_array. */ static __inline void emutls_check_array_set_size(emutls_address_array *array, uintptr_t size) { if (array == NULL) abort(); array->size = size; pthread_setspecific(emutls_pthread_key, (void *)array); } /* Returns the new 'data' array size, number of elements, * which must be no smaller than the given index. */ static __inline uintptr_t emutls_new_data_array_size(uintptr_t index) { /* Need to allocate emutls_address_array with one extra slot * to store the data array size. * Round up the emutls_address_array size to multiple of 16. */ return ((index + 1 + 15) & ~((uintptr_t)15)) - 1; } /* Returns the thread local emutls_address_array. * Extends its size if necessary to hold address at index. */ static __inline emutls_address_array * emutls_get_address_array(uintptr_t index) { emutls_address_array *array = pthread_getspecific(emutls_pthread_key); if (array == NULL) { uintptr_t new_size = emutls_new_data_array_size(index); array = (emutls_address_array *)calloc(new_size + 1, sizeof(void *)); emutls_check_array_set_size(array, new_size); } else if (index > array->size) { uintptr_t orig_size = array->size; uintptr_t new_size = emutls_new_data_array_size(index); array = (emutls_address_array *)realloc(array, (new_size + 1) * sizeof(void *)); if (array) memset(array->data + orig_size, 0, (new_size - orig_size) * sizeof(void *)); emutls_check_array_set_size(array, new_size); } return array; } void *__emutls_get_address(void *control) { uintptr_t index = emutls_get_index((__emutls_control *)control); emutls_address_array *array = emutls_get_address_array(index); if (array->data[index - 1] == NULL) array->data[index - 1] = emutls_allocate_object((__emutls_control *)control); return array->data[index - 1]; }