--- /dev/null
+// SPDX-License-Identifier: BSD-3-Clause
+/*
+ * Authors: Dragos Iulian Argint <dragosargint21@gmail.com>
+ *
+ * Copyright (c) 2022, University POLITEHNICA of Bucharest. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. 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.
+ * 3. Neither the name of the copyright holder 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 <uk/tcb_impl.h>
+#include <elf.h>
+#include <limits.h>
+#include <sys/mman.h>
+#include <string.h>
+#include <stddef.h>
+#include "pthread_impl.h"
+#include "libc.h"
+#include "atomic.h"
+#include "syscall.h"
+
+#include <uk/alloc.h>
+#include <uk/assert.h>
+
+/*
+ * This glue code source is meant to replace `__libc_start_main()`
+ * and tls related stuff.
+ * If the pthread API is used, musl will allocate the TLS and will
+ * provide a pointer to it in the `clone()` syscall. Musl will allocate
+ * in fact a contiguous region which will have the following layout (Please
+ * refer to the `pthread_create.c` file):
+ * map -----------------------------------------------------------------
+ * ^
+ * |
+ * | 4096 GUARD PAGE
+ * |
+ * v
+ * map + guard ---------------------------------------------------------
+ * ^
+ * |
+ * |
+ * | STACK
+ * |
+ * |
+ * |
+ * v
+ * stack ---------------------------------------------------------------
+ * ^ ^
+ * | | TLS SPACE
+ * | v
+ * new ->|------------------------------------------------
+ * | ^
+ * | |
+ * | |
+ * | | 280 pthread structure
+ * | |
+ * v v
+ * tsd -----------------------------------------------------------------
+ * ^
+ * | 1024
+ * v
+ * map + size ----------------------------------------------------------
+ */
+
+
+void *__uk_copy_tls(unsigned char *mem)
+{
+ pthread_t td;
+ void *tls_area;
+
+ mem -= (uintptr_t)mem & (libc.tls_align-1);
+ tls_area = mem;
+ ukarch_tls_area_init(tls_area);
+
+ td = (pthread_t) ukarch_tls_tlsp(tls_area);
+ td->dtv = td->dtv_copy = tls_area;
+
+ return td;
+}
+
+/*
+ * This function is only called for the main thread
+ */
+static int __uk_init_tp(void *p)
+{
+ pthread_t td = p;
+
+ td->self = td;
+ /*
+ * Set the `$fs` register for the current thread.
+ * In the original code of musl this will use an `arch_prtcl`
+ * syscall to fill the `$fs` register.
+ */
+ ukplat_tlsp_set((unsigned long) TP_ADJ(p));
+ libc.can_do_threads = 1;
+ /*
+ * The original musl code will invoke here a `SYS_set_tid_address`
+ * syscall, to set the tid user space address in the Kernel.
+ * FIXME: Currently this does not return the tid assigned for the caller,
+ * it returns an error code (-95) because probably there is no tid assigned
+ * at this stage. It is not a really big problem right now.
+ */
+ td->tid = uk_syscall_r_set_tid_address(&td->tid);
+ td->locale = &libc.global_locale;
+ td->robust_list.head = &td->robust_list.head;
+ return 0;
+}
+
+/*
+ * This fucntion is only called for the main thread.
+ */
+static void __uk_init_tls(void *tls_area)
+{
+ libc.tls_size = ukarch_tls_area_size();
+ libc.tls_align = ukarch_tls_area_align();
+
+ /* Failure to initialize thread pointer is always fatal. */
+ if (__uk_init_tp(tls_area) < 0)
+ UK_CRASH("Failed to initialize the main thread\n");
+}
+
+static void __uk_init_libc(void)
+{
+ libc.auxv = 0;
+ __hwcap = 0;
+ __sysinfo = 0;
+ libc.page_size = __PAGE_SIZE;
+}
+
+static const size_t __uk_tsd_size = sizeof(void *) * PTHREAD_KEYS_MAX;
+
+/*
+ * This callback will only be called for threads that are NOT
+ * created with the pthread API but we still want them to be
+ * compatible with Musl.
+ */
+int uk_thread_uktcb_init(struct uk_thread *thread, void *tcb)
+{
+ struct pthread *td = (struct pthread *) tcb;
+
+ uk_pr_debug("%s uk_thread %p, tcb %p\n", __func__, thread, tcb);
+
+ td->stack = thread->_mem.stack;
+ td->stack_size = __STACK_SIZE;
+ td->self = td;
+ td->tsd = (void *)uk_memalign(
+ uk_alloc_get_default(),
+ __PAGE_SIZE,
+ __uk_tsd_size);
+ td->locale = &libc.global_locale;
+
+ return 0;
+}
+
+/* This callback will only be called for threads that are NOT
+ * created with the pthread API
+ */
+void uk_thread_tcb_fini(struct uk_thread *thread, void *tcb)
+{
+ struct pthread *td = (struct pthread *) tcb;
+
+ uk_pr_debug("%s uk_thread %p, tcb %p\n", __func__, thread, tcb);
+ uk_free(uk_alloc_get_default(), td->tsd);
+}
+
+/*
+ * This callback is called for every thread, but we only use it
+ * to initialize the `libc` global variable and the main thread.
+ */
+void ukarch_tls_tcb_init(void *tcb)
+{
+ uk_pr_debug("%s tcb %p\n", __func__, tcb);
+
+ /*
+ * The first thread (main) will fill the `libc` global variable.
+ * This includes `tls_size`, `tls_align`. After this the
+ * `__uk_init_tls()` function is called which will initialise
+ * the `struct pthread` structure for the main thread.
+ * After this sequence of calls `libc.can_do_threads` is set to 1.
+ */
+ if (!libc.can_do_threads) {
+ __uk_init_libc();
+ __uk_init_tls(tcb);
+ }
+}
projects / unikraft / libs / musl.git / commitdiff