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
+}