summaryrefslogtreecommitdiffstats
path: root/lib/libc/i386/sys/getcontext.S
diff options
context:
space:
mode:
Diffstat (limited to 'lib/libc/i386/sys/getcontext.S')
-rw-r--r--lib/libc/i386/sys/getcontext.S53
1 files changed, 53 insertions, 0 deletions
diff --git a/lib/libc/i386/sys/getcontext.S b/lib/libc/i386/sys/getcontext.S
new file mode 100644
index 0000000..c24dbdc
--- /dev/null
+++ b/lib/libc/i386/sys/getcontext.S
@@ -0,0 +1,53 @@
+/*-
+ * Copyright (c) 2003 Peter Wemm <peter@FreeBSD.org>
+ * 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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 <machine/asm.h>
+__FBSDID("$FreeBSD$");
+
+#include <SYS.h>
+
+/*
+ * This has to be magic to handle the multiple returns.
+ * Otherwise, the setcontext() syscall will return here and we'll
+ * pop off the return address and go to the *setcontext* call.
+ */
+ .weak _getcontext
+ .set _getcontext,__sys_getcontext
+ .weak getcontext
+ .set getcontext,__sys_getcontext
+ENTRY(__sys_getcontext)
+ movl (%esp),%ecx /* save getcontext return address */
+ mov $SYS_getcontext,%eax
+ KERNCALL
+ jb 1f
+ addl $4,%esp /* remove stale (setcontext) return address */
+ jmp *%ecx /* restore return address */
+1:
+ PIC_PROLOGUE
+ jmp PIC_PLT(HIDENAME(cerror))
+END(__sys_getcontext)
+
+ .section .note.GNU-stack,"",%progbits
OpenPOWER on IntegriCloud