diff options
Diffstat (limited to 'contrib/qemu/coroutine-ucontext.c')
| -rw-r--r-- | contrib/qemu/coroutine-ucontext.c | 225 |
1 files changed, 0 insertions, 225 deletions
diff --git a/contrib/qemu/coroutine-ucontext.c b/contrib/qemu/coroutine-ucontext.c deleted file mode 100644 index 4bf2cde279b..00000000000 --- a/contrib/qemu/coroutine-ucontext.c +++ /dev/null @@ -1,225 +0,0 @@ -/* - * ucontext coroutine initialization code - * - * Copyright (C) 2006 Anthony Liguori <anthony@codemonkey.ws> - * Copyright (C) 2011 Kevin Wolf <kwolf@redhat.com> - * - * This library is free software; you can redistribute it and/or - * modify it under the terms of the GNU Lesser General Public - * License as published by the Free Software Foundation; either - * version 2.0 of the License, or (at your option) any later version. - * - * This library is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - * Lesser General Public License for more details. - * - * You should have received a copy of the GNU Lesser General Public - * License along with this library; if not, see <http://www.gnu.org/licenses/>. - */ - -/* XXX Is there a nicer way to disable glibc's stack check for longjmp? */ -#ifdef _FORTIFY_SOURCE -#undef _FORTIFY_SOURCE -#endif -#include <stdlib.h> -#include <setjmp.h> -#include <stdint.h> -#include <pthread.h> -#include <ucontext.h> -#include "qemu-common.h" -#include "block/coroutine_int.h" - -#ifdef CONFIG_VALGRIND_H -#include <valgrind/valgrind.h> -#endif - -typedef struct { - Coroutine base; - void *stack; - sigjmp_buf env; - -#ifdef CONFIG_VALGRIND_H - unsigned int valgrind_stack_id; -#endif - -} CoroutineUContext; - -/** - * Per-thread coroutine bookkeeping - */ -typedef struct { - /** Currently executing coroutine */ - Coroutine *current; - - /** The default coroutine */ - CoroutineUContext leader; -} CoroutineThreadState; - -static pthread_key_t thread_state_key; - -/* - * va_args to makecontext() must be type 'int', so passing - * the pointer we need may require several int args. This - * union is a quick hack to let us do that - */ -union cc_arg { - void *p; - int i[2]; -}; - -static CoroutineThreadState *coroutine_get_thread_state(void) -{ - CoroutineThreadState *s = pthread_getspecific(thread_state_key); - - if (!s) { - s = g_malloc0(sizeof(*s)); - s->current = &s->leader.base; - pthread_setspecific(thread_state_key, s); - } - return s; -} - -static void qemu_coroutine_thread_cleanup(void *opaque) -{ - CoroutineThreadState *s = opaque; - - g_free(s); -} - -static void __attribute__((constructor)) coroutine_init(void) -{ - int ret; - - ret = pthread_key_create(&thread_state_key, qemu_coroutine_thread_cleanup); - if (ret != 0) { - fprintf(stderr, "unable to create leader key: %s\n", strerror(errno)); - abort(); - } -} - -static void coroutine_trampoline(int i0, int i1) -{ - union cc_arg arg; - CoroutineUContext *self; - Coroutine *co; - - arg.i[0] = i0; - arg.i[1] = i1; - self = arg.p; - co = &self->base; - - /* Initialize longjmp environment and switch back the caller */ - if (!sigsetjmp(self->env, 0)) { - siglongjmp(*(sigjmp_buf *)co->entry_arg, 1); - } - - 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 = 1 << 20; - CoroutineUContext *co; - ucontext_t old_uc, uc; - sigjmp_buf old_env; - union cc_arg arg = {0}; - - /* The ucontext functions preserve signal masks which incurs a - * system call overhead. sigsetjmp(buf, 0)/siglongjmp() does not - * preserve signal masks but only works on the current stack. - * Since we need a way to create and switch to a new stack, use - * the ucontext functions for that but sigsetjmp()/siglongjmp() for - * everything else. - */ - - if (getcontext(&uc) == -1) { - abort(); - } - - co = g_malloc0(sizeof(*co)); - co->stack = g_malloc(stack_size); - co->base.entry_arg = &old_env; /* stash away our jmp_buf */ - - uc.uc_link = &old_uc; - uc.uc_stack.ss_sp = co->stack; - uc.uc_stack.ss_size = stack_size; - uc.uc_stack.ss_flags = 0; - -#ifdef CONFIG_VALGRIND_H - co->valgrind_stack_id = - VALGRIND_STACK_REGISTER(co->stack, co->stack + stack_size); -#endif - - arg.p = co; - - makecontext(&uc, (void (*)(void))coroutine_trampoline, - 2, arg.i[0], arg.i[1]); - - /* swapcontext() in, siglongjmp() back out */ - if (!sigsetjmp(old_env, 0)) { - swapcontext(&old_uc, &uc); - } - return &co->base; -} - -#ifdef CONFIG_VALGRIND_H -#ifdef CONFIG_PRAGMA_DIAGNOSTIC_AVAILABLE -/* Work around an unused variable in the valgrind.h macro... */ -#pragma GCC diagnostic push -#pragma GCC diagnostic ignored "-Wunused-but-set-variable" -#endif -static inline void valgrind_stack_deregister(CoroutineUContext *co) -{ - VALGRIND_STACK_DEREGISTER(co->valgrind_stack_id); -} -#ifdef CONFIG_PRAGMA_DIAGNOSTIC_AVAILABLE -#pragma GCC diagnostic pop -#endif -#endif - -void qemu_coroutine_delete(Coroutine *co_) -{ - CoroutineUContext *co = DO_UPCAST(CoroutineUContext, base, co_); - -#ifdef CONFIG_VALGRIND_H - valgrind_stack_deregister(co); -#endif - - g_free(co->stack); - g_free(co); -} - -CoroutineAction qemu_coroutine_switch(Coroutine *from_, Coroutine *to_, - CoroutineAction action) -{ - CoroutineUContext *from = DO_UPCAST(CoroutineUContext, base, from_); - CoroutineUContext *to = DO_UPCAST(CoroutineUContext, base, to_); - CoroutineThreadState *s = coroutine_get_thread_state(); - int ret; - - s->current = to_; - - ret = sigsetjmp(from->env, 0); - if (ret == 0) { - siglongjmp(to->env, action); - } - return ret; -} - -Coroutine *qemu_coroutine_self(void) -{ - CoroutineThreadState *s = coroutine_get_thread_state(); - - return s->current; -} - -bool qemu_in_coroutine(void) -{ - CoroutineThreadState *s = pthread_getspecific(thread_state_key); - - return s && s->current->caller; -} |