From: Stan Shebs <stanshebs@google.com>
Date: Tue, 25 Sep 2018 17:52:37 +0000 (-0700)
Subject: Add workaround for infinite looping in ppc vsyscalls
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b2d69ea7ac4b918e5325bf477bf06a3ad6685f4d;p=thirdparty%2Fglibc.git

Add workaround for infinite looping in ppc vsyscalls
---

diff --git a/sysdeps/posix/clock_getres.c b/sysdeps/posix/clock_getres.c
index 8bc7e813e60..3f6fdcf9aa8 100644
--- a/sysdeps/posix/clock_getres.c
+++ b/sysdeps/posix/clock_getres.c
@@ -73,6 +73,19 @@ realtime_getres (struct timespec *res)
   return -1;
 }
 
+#if defined __clang__ && defined __powerpc64__
+/* On ppc, __clock_getres's body eventually expands into asm code
+   that does a bctrl, but clang does not recognize the need to save
+   the link register, so calls loop infinitely instead of returning.
+   As workaround, make a dummy function call that forces a link
+   register save.  */
+volatile int clock_getres_dummy_glob;
+
+void __attribute__((noinline)) clock_getres_dummy ()
+{
+  clock_getres_dummy_glob = 45;
+}
+#endif
 
 /* Get resolution of clock.  */
 int
@@ -80,6 +93,10 @@ __clock_getres (clockid_t clock_id, struct timespec *res)
 {
   int retval = -1;
 
+#if defined __clang__ && defined __powerpc64__
+  clock_getres_dummy ();
+#endif
+
   switch (clock_id)
     {
 #ifdef SYSDEP_GETRES
diff --git a/sysdeps/unix/clock_gettime.c b/sysdeps/unix/clock_gettime.c
index 96df78ab1ed..7ef43307b5a 100644
--- a/sysdeps/unix/clock_gettime.c
+++ b/sysdeps/unix/clock_gettime.c
@@ -86,6 +86,19 @@ realtime_gettime (struct timespec *tp)
   return retval;
 }
 
+#if defined __clang__ && defined __powerpc64__
+/* On ppc, __clock_gettime's body eventually expands into asm code
+   that does a bctrl, but clang does not recognize the need to save
+   the link register, so calls loop infinitely instead of returning.
+   As workaround, make a dummy function call that forces a link
+   register save.  */
+volatile int clock_gettime_dummy_glob;
+
+void __attribute__((noinline)) clock_gettime_dummy ()
+{
+  clock_gettime_dummy_glob = 45;
+}
+#endif
 
 /* Get current value of CLOCK and store it in TP.  */
 int
@@ -93,6 +106,10 @@ __clock_gettime (clockid_t clock_id, struct timespec *tp)
 {
   int retval = -1;
 
+#if defined __clang__ && defined __powerpc64__
+  clock_gettime_dummy ();
+#endif
+
   switch (clock_id)
     {
 #ifdef SYSDEP_GETTIME