diff options
Diffstat (limited to 'libc/bionic/pthread_create.cpp')
| -rw-r--r-- | libc/bionic/pthread_create.cpp | 29 |
1 files changed, 14 insertions, 15 deletions
diff --git a/libc/bionic/pthread_create.cpp b/libc/bionic/pthread_create.cpp index 3d0daf7..f62dc15 100644 --- a/libc/bionic/pthread_create.cpp +++ b/libc/bionic/pthread_create.cpp @@ -39,9 +39,6 @@ #include "private/ErrnoRestorer.h" #include "private/ScopedPthreadMutexLocker.h" -extern "C" pid_t __bionic_clone(uint32_t flags, void* child_stack, int* parent_tid, void* tls, int* child_tid, int (*fn)(void*), void* arg); -extern "C" int __set_tls(void*); - // Used by gdb to track thread creation. See libthread_db. #ifdef __i386__ extern "C" __attribute__((noinline)) __attribute__((fastcall)) void _thread_created_hook(pid_t) {} @@ -49,6 +46,12 @@ extern "C" __attribute__((noinline)) __attribute__((fastcall)) void _thread_crea extern "C" __attribute__((noinline)) void _thread_created_hook(pid_t) {} #endif +// x86 uses segment descriptors rather than a direct pointer to TLS. +#if __i386__ +#include <asm/ldt.h> +extern "C" __LIBC_HIDDEN__ void __init_user_desc(struct user_desc*, int, void*); +#endif + static pthread_mutex_t gPthreadStackCreationLock = PTHREAD_MUTEX_INITIALIZER; static pthread_mutex_t gDebuggerNotificationLock = PTHREAD_MUTEX_INITIALIZER; @@ -62,10 +65,6 @@ void __init_tls(pthread_internal_t* thread) { thread->tls[i] = NULL; } -#if defined(__i386__) - __set_tls(thread->tls); -#endif - // Slot 0 must point to itself. The x86 Linux kernel reads the TLS from %fs:0. thread->tls[TLS_SLOT_SELF] = thread->tls; thread->tls[TLS_SLOT_THREAD_ID] = thread; @@ -148,8 +147,7 @@ static int __pthread_start(void* arg) { pthread_mutex_t* start_mutex = (pthread_mutex_t*) &thread->tls[TLS_SLOT_START_MUTEX]; pthread_mutex_lock(start_mutex); pthread_mutex_destroy(start_mutex); - - __init_tls(thread); + thread->tls[TLS_SLOT_START_MUTEX] = NULL; __init_alternate_signal_stack(thread); @@ -208,6 +206,7 @@ int pthread_create(pthread_t* thread_out, pthread_attr_t const* attr, // At offsets < 0, we have the child stack. thread->tls = (void**)((uint8_t*)(thread->attr.stack_base) + thread->attr.stack_size - BIONIC_TLS_SLOTS * sizeof(void*)); void* child_stack = thread->tls; + __init_tls(thread); // Create a mutex for the thread in TLS to wait on once it starts so we can keep // it from doing anything until after we notify the debugger about it @@ -219,20 +218,20 @@ int pthread_create(pthread_t* thread_out, pthread_attr_t const* attr, pthread_mutex_init(start_mutex, NULL); pthread_mutex_lock(start_mutex); - thread->tls[TLS_SLOT_THREAD_ID] = thread; - thread->start_routine = start_routine; thread->start_routine_arg = arg; int flags = CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND | CLONE_THREAD | CLONE_SYSVSEM | CLONE_SETTLS | CLONE_PARENT_SETTID | CLONE_CHILD_CLEARTID; + void* tls = thread->tls; #if defined(__i386__) // On x86 (but not x86-64), CLONE_SETTLS takes a pointer to a struct user_desc rather than - // a pointer to the TLS itself. Rather than try to deal with that here, we just let x86 set - // the TLS manually in __init_tls, like all architectures used to. - flags &= ~CLONE_SETTLS; + // a pointer to the TLS itself. + user_desc tls_descriptor; + __init_user_desc(&tls_descriptor, false, tls); + tls = &tls_descriptor; #endif - int rc = __bionic_clone(flags, child_stack, &(thread->tid), thread->tls, &(thread->tid), __pthread_start, thread); + int rc = clone(__pthread_start, child_stack, flags, thread, &(thread->tid), tls, &(thread->tid)); if (rc == -1) { int clone_errno = errno; // We don't have to unlock the mutex at all because clone(2) failed so there's no child waiting to |