/* * Win32 coroutine initialization code * * Copyright (c) 2011 Kevin Wolf <kwolf@redhat.com> * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN * THE SOFTWARE. */ #include "qemu/osdep.h" #include "qemu-common.h" #include "qemu/coroutine_int.h" typedef struct { Coroutine base; LPVOID fiber; CoroutineAction action; } CoroutineWin32; static __thread CoroutineWin32 leader; static __thread Coroutine *current; /* This function is marked noinline to prevent GCC from inlining it * into coroutine_trampoline(). If we allow it to do that then it * hoists the code to get the address of the TLS variable "current" * out of the while() loop. This is an invalid transformation because * the SwitchToFiber() call may be called when running thread A but * return in thread B, and so we might be in a different thread * context each time round the loop. */ CoroutineAction __attribute__((noinline)) qemu_coroutine_switch(Coroutine *from_, Coroutine *to_, CoroutineAction action) { CoroutineWin32 *from = DO_UPCAST(CoroutineWin32, base, from_); CoroutineWin32 *to = DO_UPCAST(CoroutineWin32, base, to_); current = to_; to->action = action; SwitchToFiber(to->fiber); return from->action; } static void CALLBACK coroutine_trampoline(void *co_) { Coroutine *co = co_; while (true) { co->entry(co->entry_arg); qemu_coroutine_switch(co, co->caller, COROUTINE_TERMINATE); } } Coroutine *qemu_coroutine_new(void) { const size_t stack_size = COROUTINE_STACK_SIZE; CoroutineWin32 *co; co = g_malloc0(sizeof(*co)); co->fiber = CreateFiber(stack_size, coroutine_trampoline, &co->base); return &co->base; } void qemu_coroutine_delete(Coroutine *co_) { CoroutineWin32 *co = DO_UPCAST(CoroutineWin32, base, co_); DeleteFiber(co->fiber); g_free(co); } Coroutine *qemu_coroutine_self(void) { if (!current) { current = &leader.base; leader.fiber = ConvertThreadToFiber(NULL); } return current; } bool qemu_in_coroutine(void) { return current && current->caller; }