Index: include/vki-amd64-linux.h
===================================================================
--- include/vki-amd64-linux.h	(revision 6565)
+++ include/vki-amd64-linux.h	(working copy)
@@ -240,6 +240,8 @@ struct vki_sigcontext { 
 #define VKI_O_NONBLOCK	  04000
 #define VKI_O_LARGEFILE	0100000
 
+#define VKI_AT_FDCWD            -100
+
 #define VKI_F_DUPFD		0	/* dup */
 #define VKI_F_GETFD		1	/* get close_on_exec */
 #define VKI_F_SETFD		2	/* set/clear close_on_exec */
Index: include/vki-ppc32-linux.h
===================================================================
--- include/vki-ppc32-linux.h	(revision 6565)
+++ include/vki-ppc32-linux.h	(working copy)
@@ -300,6 +300,8 @@ struct vki_sigcontext {
 #define VKI_O_NONBLOCK		04000
 #define VKI_O_LARGEFILE     0200000
 
+#define VKI_AT_FDCWD            -100
+
 #define VKI_F_DUPFD		 0			/* dup */
 #define VKI_F_GETFD		 1			/* get close_on_exec */
 #define VKI_F_SETFD		 2			/* set/clear close_on_exec */
Index: include/vki-x86-linux.h
===================================================================
--- include/vki-x86-linux.h	(revision 6565)
+++ include/vki-x86-linux.h	(working copy)
@@ -272,6 +272,8 @@ struct vki_sigcontext {
 #define VKI_O_NONBLOCK	  04000
 #define VKI_O_LARGEFILE	0100000
 
+#define VKI_AT_FDCWD            -100
+
 #define VKI_F_DUPFD		0	/* dup */
 #define VKI_F_GETFD		1	/* get close_on_exec */
 #define VKI_F_SETFD		2	/* set/clear close_on_exec */
Index: include/vki-ppc64-linux.h
===================================================================
--- include/vki-ppc64-linux.h	(revision 6565)
+++ include/vki-ppc64-linux.h	(working copy)
@@ -357,6 +357,8 @@ struct vki_sigcontext {
 #define VKI_O_NONBLOCK        04000
 #define VKI_O_LARGEFILE     0200000
 
+#define VKI_AT_FDCWD            -100
+
 #define VKI_F_DUPFD         0       /* dup */
 #define VKI_F_GETFD         1       /* get close_on_exec */
 #define VKI_F_SETFD         2       /* set/clear close_on_exec */
Index: coregrind/m_syswrap/syswrap-linux.c
===================================================================
--- coregrind/m_syswrap/syswrap-linux.c	(revision 6565)
+++ coregrind/m_syswrap/syswrap-linux.c	(working copy)
@@ -2434,7 +2434,7 @@ PRE(sys_openat)
                     int, dfd, const char *, filename, int, flags);
    }
 
-   if (!ML_(fd_allowed)(ARG1, "openat", tid, False))
+   if (ARG1 != VKI_AT_FDCWD && !ML_(fd_allowed)(ARG1, "openat", tid, False))
       SET_STATUS_Failure( VKI_EBADF );
    else
       PRE_MEM_RASCIIZ( "openat(filename)", ARG2 );