base/SOURCES/glibc-rh841653-16.patch

Index: glibc-2.17-c758a686/elf/rtld.c
===================================================================
--- glibc-2.17-c758a686.orig/elf/rtld.c
+++ glibc-2.17-c758a686/elf/rtld.c
@@ -2478,6 +2478,11 @@ process_envvars (enum mode *modep)
   GLRO(dl_profile_output)
     = &"/var/tmp\0/var/profile"[INTUSE(__libc_enable_secure) ? 9 : 0];

+  /* RHEL 7 specific change:
+     Without the tunables farmework we simulate tunables only for
+     use with enabling transactional memory.  */
+  _dl_process_tunable_env_entries ();
+
   while ((envline = _dl_next_ld_env_entry (&runp)) != NULL)
     {
       size_t len = 0;
Index: glibc-2.17-c758a686/nptl/sysdeps/unix/sysv/linux/x86/elision-conf.c
===================================================================
--- glibc-2.17-c758a686.orig/nptl/sysdeps/unix/sysv/linux/x86/elision-conf.c
+++ glibc-2.17-c758a686/nptl/sysdeps/unix/sysv/linux/x86/elision-conf.c
@@ -68,8 +68,18 @@ elision_init (int argc __attribute__ ((u
 {
   int elision_available = HAS_CPU_FEATURE (RTM);
 #ifdef ENABLE_LOCK_ELISION
-  __pthread_force_elision = __libc_enable_secure ? 0 : elision_available;
-  __rwlock_rtm_enabled = __libc_enable_secure ? 0 : elision_available;
+  if (!__libc_enable_secure && elision_available)
+    {
+      /* RHEL 7 specific change: Check if elision is enabled for the
+	 process.  */
+      __pthread_force_elision = GLRO(dl_elision_enabled);
+      __rwlock_rtm_enabled = GLRO(dl_elision_enabled);
+    }
+  else
+    {
+      __pthread_force_elision = 0;
+      __rwlock_rtm_enabled = 0;
+    }
 #endif
 }

Index: glibc-2.17-c758a686/sysdeps/generic/ldsodefs.h
===================================================================
--- glibc-2.17-c758a686.orig/sysdeps/generic/ldsodefs.h
+++ glibc-2.17-c758a686/sysdeps/generic/ldsodefs.h
@@ -557,6 +557,9 @@ struct rtld_global_ro
      platforms.  */
   EXTERN uint64_t _dl_hwcap2;

+  /* RHEL 7 specific change: Is elision enabled for this process?  */
+  EXTERN bool _dl_elision_enabled;
+
 #ifdef SHARED
   /* We add a function table to _rtld_global which is then used to
      call the function instead of going through the PLT.  The result
@@ -893,6 +896,10 @@ extern void _dl_show_auxv (void) interna
    other.  */
 extern char *_dl_next_ld_env_entry (char ***position) internal_function;

+/* RHEL 7 specific change:
+   Manually process RHEL 7-specific tunable entries.  */
+extern void _dl_process_tunable_env_entries (void) internal_function;
+
 /* Return an array with the names of the important hardware capabilities.  */
 extern const struct r_strlenpair *_dl_important_hwcaps (const char *platform,
							size_t paltform_len,
Index: glibc-2.17-c758a686/elf/dl-support.c
===================================================================
--- glibc-2.17-c758a686.orig/elf/dl-support.c
+++ glibc-2.17-c758a686/elf/dl-support.c
@@ -123,6 +123,10 @@ size_t _dl_phnum;
 uint64_t _dl_hwcap __attribute__ ((nocommon));
 uint64_t _dl_hwcap2 __attribute__ ((nocommon));

+/* RHEL 7-specific change: Is elision enabled for the process?
+   Static library definition.  */
+bool _dl_elision_enabled;
+
 /* This is not initialized to HWCAP_IMPORTANT, matching the definition
    of _dl_important_hwcaps, below, where no hwcap strings are ever
    used.  This mask is still used to mediate the lookups in the cache
@@ -289,6 +293,9 @@ _dl_non_dynamic_init (void)
     _dl_profile_output
       = &"/var/tmp\0/var/profile"[__libc_enable_secure ? 9 : 0];

+  /* RHEL 7 specific change: Process tunables at startup.  */
+  _dl_process_tunable_env_entries ();
+
   if (__libc_enable_secure)
     {
       static const char unsecure_envvars[] =
Index: glibc-2.17-c758a686/sysdeps/x86_64/multiarch/strstr-c.c
===================================================================
--- glibc-2.17-c758a686.orig/sysdeps/x86_64/multiarch/strstr-c.c
+++ glibc-2.17-c758a686/sysdeps/x86_64/multiarch/strstr-c.c
@@ -17,6 +17,10 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */

+/* RHEL 7-specific: Define multiple versions only for the definition in
+   libc.  Don't define multiple versions for strstr in static library
+   since we need strstr before initialization has happened.  */
+#if defined SHARED && IS_IN (libc)
 /* Redefine strstr so that the compiler won't complain about the type
    mismatch with the IFUNC selector in strong_alias, below.  */
 #undef  strstr
@@ -30,9 +34,11 @@
 # define libc_hidden_builtin_def(name) \
   __hidden_ver1 (__strstr_sse2, __GI_strstr, __strstr_sse2);
 #endif
+#endif

 #include "string/strstr.c"

+#if defined SHARED && IS_IN (libc)
 extern __typeof (__redirect_strstr) __strstr_sse42 attribute_hidden;
 extern __typeof (__redirect_strstr) __strstr_sse2_unaligned attribute_hidden;
 extern __typeof (__redirect_strstr) __strstr_sse2 attribute_hidden;
@@ -48,3 +54,5 @@ libc_ifunc (__libc_strstr, HAS_CPU_FEATU

 #undef strstr
 strong_alias (__libc_strstr, strstr)
+#endif
+
Index: glibc-2.17-c758a686/elf/Makefile
===================================================================
--- glibc-2.17-c758a686.orig/elf/Makefile
+++ glibc-2.17-c758a686/elf/Makefile
@@ -35,6 +35,10 @@ dl-routines	= $(addprefix dl-,load looku
 ifeq (yes,$(use-ldconfig))
 dl-routines += dl-cache
 endif
+
+# RHEL 7-specific change: Add rudimentary tunables support.
+dl-routines += dl-tunables
+
 all-dl-routines = $(dl-routines) $(sysdep-dl-routines)
 # But they are absent from the shared libc, because that code is in ld.so.
 elide-routines.os = $(all-dl-routines) dl-support enbl-secure dl-origin \
Index: glibc-2.17-c758a686/elf/dl-tunables.c
===================================================================
--- /dev/null
+++ glibc-2.17-c758a686/elf/dl-tunables.c
@@ -0,0 +1,60 @@
+/* RHEL 7-specific rudimentary tunables handling.
+   Copyright (C) 2017 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 <string.h>
+#include <unistd.h>
+#include <ldsodefs.h>
+#include <elision-conf.h>
+
+/* RHEL 7 specific change:
+   Manually process RHEL 7-specific tunable entries.  */
+void
+internal_function
+_dl_process_tunable_env_entries (void)
+{
+#if HAVE_ELISION
+  char **ep;
+  const char *envname = { "RHEL_GLIBC_TUNABLES" };
+# define TUNABLE_ELISION 0
+# define TUNABLE_MAX 1
+  const char *tunables[TUNABLE_MAX] = { "glibc.elision.enable=1" };
+
+  ep = __environ;
+  while (*ep != NULL)
+    {
+      size_t cnt = 0;
+
+      while ((*ep)[cnt] == envname[cnt] && envname[cnt] != '\0')
+        ++cnt;
+
+      if (envname[cnt] == '\0' && (*ep)[cnt] == '=')
+        {
+          /* Found it.  */
+          char *found;
+          found = strstr (*ep, tunables[TUNABLE_ELISION]);
+          /* Process TUNABLE_ELISION:
+             Note: elision-conf.c applies security checks.  */
+          if (found != NULL)
+	    GLRO(dl_elision_enabled) = true;
+          /* Continue the loop in case NAME appears again.  */
+        }
+
+      ++ep;
+    }
+#endif
+}