1 files changed, 71 insertions, 0 deletions
diff --git a/sysdeps/x86/nptl/pt-longjmp.c b/sysdeps/x86/nptl/pt-longjmp.c
new file mode 100644
index 0000000000..6165c7d4a7
--- /dev/null
+++ b/sysdeps/x86/nptl/pt-longjmp.c
@@ -0,0 +1,71 @@
+/* ABI compatibility for 'longjmp' and 'siglongjmp' symbols in libpthread ABI.
+   X86 version.
+   Copyright (C) 18 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C 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 2.1 of the License, or (at your option) any later version.
+
+   The GNU C 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 the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <pthreadP.h>
+#include <jmp_buf-ssp.h>
+
+#ifdef __x86_64__
+# define SHADOW_STACK_POINTER_SIZE 8
+#else
+# define SHADOW_STACK_POINTER_SIZE 4
+#endif
+
+/* Assert that the priv field in struct pthread_unwind_buf has space
+   to store shadow stack pointer.  */
+_Static_assert ((offsetof (struct pthread_unwind_buf, priv)
+		 <= SHADOW_STACK_POINTER_OFFSET)
+		&& ((offsetof (struct pthread_unwind_buf, priv)
+		     + sizeof (((struct pthread_unwind_buf *) 0)->priv))
+		    >= (SHADOW_STACK_POINTER_OFFSET
+			+ SHADOW_STACK_POINTER_SIZE)),
+		"Shadow stack pointer is not within private storage "
+		"of pthread_unwind_buf.");
+
+#include <shlib-compat.h>
+
+/* libpthread once had its own longjmp (and siglongjmp alias), though there
+   was no apparent reason for it.  There is no use in having a separate
+   symbol in libpthread, but the historical ABI requires it.  For static
+   linking, there is no need to provide anything here--the libc version
+   will be linked in.  For shared library ABI compatibility, there must be
+   longjmp and siglongjmp symbols in libpthread.so.
+
+   With an IFUNC resolver, it would be possible to avoid the indirection,
+   but the IFUNC resolver might run before the __libc_longjmp symbol has
+   been relocated, in which case the IFUNC resolver would not be able to
+   provide the correct address.  */
+
+#if SHLIB_COMPAT (libpthread, GLIBC_2_0, GLIBC_2_22)
+
+static void __attribute__ ((noreturn, used))
+longjmp_compat (jmp_buf env, int val)
+{
+  /* NB: We call __libc_siglongjmp,  instead of __libc_longjmp, since
+     __libc_longjmp is a private interface for cancellation which
+     doesn't restore shadow stack register.  */
+  __libc_siglongjmp (env, val);
+}
+
+strong_alias (longjmp_compat, longjmp_alias)
+compat_symbol (libpthread, longjmp_alias, longjmp, GLIBC_2_0);
+
+strong_alias (longjmp_alias, siglongjmp_alias)
+compat_symbol (libpthread, siglongjmp_alias, siglongjmp, GLIBC_2_0);
+
+#endif