diff --git a/library/threading.c b/library/threading.c
new file mode 100644
index 0000000..85db243
--- /dev/null
+++ b/library/threading.c
@@ -0,0 +1,195 @@
+/*
+ *  Threading abstraction layer
+ *
+ *  Copyright The Mbed TLS Contributors
+ *  SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
+ */
+
+/*
+ * Ensure gmtime_r is available even with -std=c99; must be defined before
+ * mbedtls_config.h, which pulls in glibc's features.h. Harmless on other platforms.
+ */
+#if !defined(_POSIX_C_SOURCE)
+#define _POSIX_C_SOURCE 200112L
+#endif
+
+#include "common.h"
+
+#if defined(MBEDTLS_THREADING_C)
+
+#include "mbedtls/threading.h"
+
+#if defined(MBEDTLS_HAVE_TIME_DATE) && !defined(MBEDTLS_PLATFORM_GMTIME_R_ALT)
+
+#if !defined(_WIN32) && (defined(unix) || \
+    defined(__unix) || defined(__unix__) || (defined(__APPLE__) && \
+    defined(__MACH__)))
+#include <unistd.h>
+#endif /* !_WIN32 && (unix || __unix || __unix__ ||
+        * (__APPLE__ && __MACH__)) */
+
+#if !((defined(_POSIX_VERSION) && _POSIX_VERSION >= 200809L) ||     \
+    (defined(_POSIX_THREAD_SAFE_FUNCTIONS) &&                     \
+    _POSIX_THREAD_SAFE_FUNCTIONS >= 200112L))
+/*
+ * This is a convenience shorthand macro to avoid checking the long
+ * preprocessor conditions above. Ideally, we could expose this macro in
+ * platform_util.h and simply use it in platform_util.c, threading.c and
+ * threading.h. However, this macro is not part of the Mbed TLS public API, so
+ * we keep it private by only defining it in this file
+ */
+
+#if !(defined(_WIN32) && !defined(EFIX64) && !defined(EFI32))
+#define THREADING_USE_GMTIME
+#endif /* ! ( defined(_WIN32) && !defined(EFIX64) && !defined(EFI32) ) */
+
+#endif /* !( ( defined(_POSIX_VERSION) && _POSIX_VERSION >= 200809L ) || \
+             ( defined(_POSIX_THREAD_SAFE_FUNCTIONS ) && \
+                _POSIX_THREAD_SAFE_FUNCTIONS >= 200112L ) ) */
+
+#endif /* MBEDTLS_HAVE_TIME_DATE && !MBEDTLS_PLATFORM_GMTIME_R_ALT */
+
+#if defined(MBEDTLS_THREADING_PTHREAD)
+static void threading_mutex_init_pthread(mbedtls_threading_mutex_t *mutex)
+{
+    if (mutex == NULL) {
+        return;
+    }
+
+    /* One problem here is that calling lock on a pthread mutex without first
+     * having initialised it is undefined behaviour. Obviously we cannot check
+     * this here in a thread safe manner without a significant performance
+     * hit, so state transitions are checked in tests only via the state
+     * variable. Please make sure any new mutex that gets added is exercised in
+     * tests; see tests/src/threading_helpers.c for more details. */
+    (void) pthread_mutex_init(&mutex->mutex, NULL);
+}
+
+static void threading_mutex_free_pthread(mbedtls_threading_mutex_t *mutex)
+{
+    if (mutex == NULL) {
+        return;
+    }
+
+    (void) pthread_mutex_destroy(&mutex->mutex);
+}
+
+static int threading_mutex_lock_pthread(mbedtls_threading_mutex_t *mutex)
+{
+    if (mutex == NULL) {
+        return MBEDTLS_ERR_THREADING_BAD_INPUT_DATA;
+    }
+
+    if (pthread_mutex_lock(&mutex->mutex) != 0) {
+        return MBEDTLS_ERR_THREADING_MUTEX_ERROR;
+    }
+
+    return 0;
+}
+
+static int threading_mutex_unlock_pthread(mbedtls_threading_mutex_t *mutex)
+{
+    if (mutex == NULL) {
+        return MBEDTLS_ERR_THREADING_BAD_INPUT_DATA;
+    }
+
+    if (pthread_mutex_unlock(&mutex->mutex) != 0) {
+        return MBEDTLS_ERR_THREADING_MUTEX_ERROR;
+    }
+
+    return 0;
+}
+
+void (*mbedtls_mutex_init)(mbedtls_threading_mutex_t *) = threading_mutex_init_pthread;
+void (*mbedtls_mutex_free)(mbedtls_threading_mutex_t *) = threading_mutex_free_pthread;
+int (*mbedtls_mutex_lock)(mbedtls_threading_mutex_t *) = threading_mutex_lock_pthread;
+int (*mbedtls_mutex_unlock)(mbedtls_threading_mutex_t *) = threading_mutex_unlock_pthread;
+
+/*
+ * With pthreads we can statically initialize mutexes
+ */
+#define MUTEX_INIT  = { PTHREAD_MUTEX_INITIALIZER, 1 }
+
+#endif /* MBEDTLS_THREADING_PTHREAD */
+
+#if defined(MBEDTLS_THREADING_ALT)
+static int threading_mutex_fail(mbedtls_threading_mutex_t *mutex)
+{
+    ((void) mutex);
+    return MBEDTLS_ERR_THREADING_BAD_INPUT_DATA;
+}
+static void threading_mutex_dummy(mbedtls_threading_mutex_t *mutex)
+{
+    ((void) mutex);
+    return;
+}
+
+void (*mbedtls_mutex_init)(mbedtls_threading_mutex_t *) = threading_mutex_dummy;
+void (*mbedtls_mutex_free)(mbedtls_threading_mutex_t *) = threading_mutex_dummy;
+int (*mbedtls_mutex_lock)(mbedtls_threading_mutex_t *) = threading_mutex_fail;
+int (*mbedtls_mutex_unlock)(mbedtls_threading_mutex_t *) = threading_mutex_fail;
+
+/*
+ * Set functions pointers and initialize global mutexes
+ */
+void mbedtls_threading_set_alt(void (*mutex_init)(mbedtls_threading_mutex_t *),
+                               void (*mutex_free)(mbedtls_threading_mutex_t *),
+                               int (*mutex_lock)(mbedtls_threading_mutex_t *),
+                               int (*mutex_unlock)(mbedtls_threading_mutex_t *))
+{
+    mbedtls_mutex_init = mutex_init;
+    mbedtls_mutex_free = mutex_free;
+    mbedtls_mutex_lock = mutex_lock;
+    mbedtls_mutex_unlock = mutex_unlock;
+
+#if defined(MBEDTLS_FS_IO)
+    mbedtls_mutex_init(&mbedtls_threading_readdir_mutex);
+#endif
+#if defined(THREADING_USE_GMTIME)
+    mbedtls_mutex_init(&mbedtls_threading_gmtime_mutex);
+#endif
+#if defined(MBEDTLS_PSA_CRYPTO_C)
+    mbedtls_mutex_init(&mbedtls_threading_key_slot_mutex);
+    mbedtls_mutex_init(&mbedtls_threading_psa_globaldata_mutex);
+    mbedtls_mutex_init(&mbedtls_threading_psa_rngdata_mutex);
+#endif
+}
+
+/*
+ * Free global mutexes
+ */
+void mbedtls_threading_free_alt(void)
+{
+#if defined(MBEDTLS_FS_IO)
+    mbedtls_mutex_free(&mbedtls_threading_readdir_mutex);
+#endif
+#if defined(THREADING_USE_GMTIME)
+    mbedtls_mutex_free(&mbedtls_threading_gmtime_mutex);
+#endif
+#if defined(MBEDTLS_PSA_CRYPTO_C)
+    mbedtls_mutex_free(&mbedtls_threading_key_slot_mutex);
+    mbedtls_mutex_free(&mbedtls_threading_psa_globaldata_mutex);
+    mbedtls_mutex_free(&mbedtls_threading_psa_rngdata_mutex);
+#endif
+}
+#endif /* MBEDTLS_THREADING_ALT */
+
+/*
+ * Define global mutexes
+ */
+#ifndef MUTEX_INIT
+#define MUTEX_INIT
+#endif
+#if defined(MBEDTLS_FS_IO)
+mbedtls_threading_mutex_t mbedtls_threading_readdir_mutex MUTEX_INIT;
+#endif
+#if defined(THREADING_USE_GMTIME)
+mbedtls_threading_mutex_t mbedtls_threading_gmtime_mutex MUTEX_INIT;
+#endif
+#if defined(MBEDTLS_PSA_CRYPTO_C)
+mbedtls_threading_mutex_t mbedtls_threading_key_slot_mutex MUTEX_INIT;
+mbedtls_threading_mutex_t mbedtls_threading_psa_globaldata_mutex MUTEX_INIT;
+mbedtls_threading_mutex_t mbedtls_threading_psa_rngdata_mutex MUTEX_INIT;
+#endif
+
+#endif /* MBEDTLS_THREADING_C */