|
 |
00db10 |
commit b9eb92ab05204df772eb4929eccd018637c9f3e9
|
|
|
00db10 |
Author: H.J. Lu <hjl.tools@gmail.com>
|
|
|
00db10 |
Date: Wed Oct 21 14:44:23 2015 -0700
|
|
|
00db10 |
|
|
|
00db10 |
Add Prefer_MAP_32BIT_EXEC to map executable pages with MAP_32BIT
|
|
|
00db10 |
|
|
|
00db10 |
According to Silvermont software optimization guide, for 64-bit
|
|
|
00db10 |
applications, branch prediction performance can be negatively impacted
|
|
|
00db10 |
when the target of a branch is more than 4GB away from the branch. Add
|
|
|
00db10 |
the Prefer_MAP_32BIT_EXEC bit so that mmap will try to map executable
|
|
|
00db10 |
pages with MAP_32BIT first. NB: MAP_32BIT will map to lower 2GB, not
|
|
|
00db10 |
lower 4GB, address. Prefer_MAP_32BIT_EXEC reduces bits available for
|
|
|
00db10 |
address space layout randomization (ASLR), which is always disabled for
|
|
|
00db10 |
SUID programs and can only be enabled by setting environment variable,
|
|
|
00db10 |
LD_PREFER_MAP_32BIT_EXEC.
|
|
|
00db10 |
|
|
|
00db10 |
On Fedora 23, this patch speeds up GCC 5 testsuite by 3% on Silvermont.
|
|
|
00db10 |
|
|
|
00db10 |
[BZ #19367]
|
|
|
00db10 |
* sysdeps/unix/sysv/linux/wordsize-64/mmap.c: New file.
|
|
|
00db10 |
* sysdeps/unix/sysv/linux/x86_64/64/dl-librecon.h: Likewise.
|
|
|
00db10 |
* sysdeps/unix/sysv/linux/x86_64/64/mmap.c: Likewise.
|
|
|
00db10 |
* sysdeps/x86/cpu-features.h (bit_Prefer_MAP_32BIT_EXEC): New.
|
|
|
00db10 |
(index_Prefer_MAP_32BIT_EXEC): Likewise.
|
|
|
00db10 |
|
|
|
00db10 |
Index: glibc-2.17-c758a686/sysdeps/unix/sysv/linux/wordsize-64/mmap.c
|
|
|
00db10 |
===================================================================
|
|
|
00db10 |
--- /dev/null
|
|
|
00db10 |
+++ glibc-2.17-c758a686/sysdeps/unix/sysv/linux/wordsize-64/mmap.c
|
|
|
00db10 |
@@ -0,0 +1,40 @@
|
|
|
00db10 |
+/* Linux mmap system call. 64-bit version.
|
|
|
00db10 |
+ Copyright (C) 2015 Free Software Foundation, Inc.
|
|
|
00db10 |
+
|
|
|
00db10 |
+ This file is part of the GNU C Library.
|
|
|
00db10 |
+
|
|
|
00db10 |
+ The GNU C Library is free software; you can redistribute it and/or
|
|
|
00db10 |
+ modify it under the terms of the GNU Lesser General Public License as
|
|
|
00db10 |
+ published by the Free Software Foundation; either version 2.1 of the
|
|
|
00db10 |
+ License, or (at your option) any later version.
|
|
|
00db10 |
+
|
|
|
00db10 |
+ The GNU C Library is distributed in the hope that it will be useful,
|
|
|
00db10 |
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
|
00db10 |
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
|
00db10 |
+ Lesser General Public License for more details.
|
|
|
00db10 |
+
|
|
|
00db10 |
+ You should have received a copy of the GNU Lesser General Public
|
|
|
00db10 |
+ License along with the GNU C Library; if not, see
|
|
|
00db10 |
+ <http://www.gnu.org/licenses/>. */
|
|
|
00db10 |
+
|
|
|
00db10 |
+#include <sys/types.h>
|
|
|
00db10 |
+#include <sys/mman.h>
|
|
|
00db10 |
+#include <errno.h>
|
|
|
00db10 |
+#include <sysdep.h>
|
|
|
00db10 |
+
|
|
|
00db10 |
+/* An architecture may override this. */
|
|
|
00db10 |
+#ifndef MMAP_PREPARE
|
|
|
00db10 |
+# define MMAP_PREPARE(addr, len, prot, flags, fd, offset)
|
|
|
00db10 |
+#endif
|
|
|
00db10 |
+
|
|
|
00db10 |
+__ptr_t
|
|
|
00db10 |
+__mmap (__ptr_t addr, size_t len, int prot, int flags, int fd, off_t offset)
|
|
|
00db10 |
+{
|
|
|
00db10 |
+ MMAP_PREPARE (addr, len, prot, flags, fd, offset);
|
|
|
00db10 |
+ return (__ptr_t) INLINE_SYSCALL (mmap, 6, addr, len, prot, flags,
|
|
|
00db10 |
+ fd, offset);
|
|
|
00db10 |
+}
|
|
|
00db10 |
+
|
|
|
00db10 |
+weak_alias (__mmap, mmap)
|
|
|
00db10 |
+weak_alias (__mmap, mmap64)
|
|
|
00db10 |
+weak_alias (__mmap, __mmap64)
|
|
|
00db10 |
Index: glibc-2.17-c758a686/sysdeps/unix/sysv/linux/x86_64/64/dl-librecon.h
|
|
|
00db10 |
===================================================================
|
|
|
00db10 |
--- /dev/null
|
|
|
00db10 |
+++ glibc-2.17-c758a686/sysdeps/unix/sysv/linux/x86_64/64/dl-librecon.h
|
|
|
00db10 |
@@ -0,0 +1,44 @@
|
|
|
00db10 |
+/* Optional code to distinguish library flavours. x86-64 version.
|
|
|
00db10 |
+ Copyright (C) 2015 Free Software Foundation, Inc.
|
|
|
00db10 |
+ This file is part of the GNU C Library.
|
|
|
00db10 |
+
|
|
|
00db10 |
+ The GNU C Library is free software; you can redistribute it and/or
|
|
|
00db10 |
+ modify it under the terms of the GNU Lesser General Public
|
|
|
00db10 |
+ License as published by the Free Software Foundation; either
|
|
|
00db10 |
+ version 2.1 of the License, or (at your option) any later version.
|
|
|
00db10 |
+
|
|
|
00db10 |
+ The GNU C Library is distributed in the hope that it will be useful,
|
|
|
00db10 |
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
|
00db10 |
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
|
00db10 |
+ Lesser General Public License for more details.
|
|
|
00db10 |
+
|
|
|
00db10 |
+ You should have received a copy of the GNU Lesser General Public
|
|
|
00db10 |
+ License along with the GNU C Library; if not, see
|
|
|
00db10 |
+ <http://www.gnu.org/licenses/>. */
|
|
|
00db10 |
+
|
|
|
00db10 |
+#ifndef _DL_LIBRECON_H
|
|
|
00db10 |
+
|
|
|
00db10 |
+#include <sysdeps/unix/sysv/linux/dl-librecon.h>
|
|
|
00db10 |
+
|
|
|
00db10 |
+/* Recognizing extra environment variables. For 64-bit applications,
|
|
|
00db10 |
+ branch prediction performance may be negatively impacted when the
|
|
|
00db10 |
+ target of a branch is more than 4GB away from the branch. Add the
|
|
|
00db10 |
+ Prefer_MAP_32BIT_EXEC bit so that mmap will try to map executable
|
|
|
00db10 |
+ pages with MAP_32BIT first. NB: MAP_32BIT will map to lower 2GB,
|
|
|
00db10 |
+ not lower 4GB, address. Prefer_MAP_32BIT_EXEC reduces bits available
|
|
|
00db10 |
+ for address space layout randomization (ASLR). Prefer_MAP_32BIT_EXEC
|
|
|
00db10 |
+ is always disabled for SUID programs and can be enabled by setting
|
|
|
00db10 |
+ environment variable, LD_PREFER_MAP_32BIT_EXEC. */
|
|
|
00db10 |
+#define EXTRA_LD_ENVVARS \
|
|
|
00db10 |
+ case 21: \
|
|
|
00db10 |
+ if (memcmp (envline, "PREFER_MAP_32BIT_EXEC", 21) == 0) \
|
|
|
00db10 |
+ GLRO(dl_x86_cpu_features).feature[index_Prefer_MAP_32BIT_EXEC] \
|
|
|
00db10 |
+ = bit_Prefer_MAP_32BIT_EXEC; \
|
|
|
00db10 |
+ break;
|
|
|
00db10 |
+
|
|
|
00db10 |
+/* Extra unsecure variables. The names are all stuffed in a single
|
|
|
00db10 |
+ string which means they have to be terminated with a '\0' explicitly. */
|
|
|
00db10 |
+#define EXTRA_UNSECURE_ENVVARS \
|
|
|
00db10 |
+ "LD_PREFER_MAP_32BIT_EXEC\0"
|
|
|
00db10 |
+
|
|
|
00db10 |
+#endif /* dl-librecon.h */
|
|
|
00db10 |
Index: glibc-2.17-c758a686/sysdeps/unix/sysv/linux/x86_64/64/mmap.c
|
|
|
00db10 |
===================================================================
|
|
|
00db10 |
--- /dev/null
|
|
|
00db10 |
+++ glibc-2.17-c758a686/sysdeps/unix/sysv/linux/x86_64/64/mmap.c
|
|
|
00db10 |
@@ -0,0 +1,37 @@
|
|
|
00db10 |
+/* Linux mmap system call. x86-64 version.
|
|
|
00db10 |
+ Copyright (C) 2015 Free Software Foundation, Inc.
|
|
|
00db10 |
+
|
|
|
00db10 |
+ This file is part of the GNU C Library.
|
|
|
00db10 |
+
|
|
|
00db10 |
+ The GNU C Library is free software; you can redistribute it and/or
|
|
|
00db10 |
+ modify it under the terms of the GNU Lesser General Public License as
|
|
|
00db10 |
+ published by the Free Software Foundation; either version 2.1 of the
|
|
|
00db10 |
+ License, or (at your option) any later version.
|
|
|
00db10 |
+
|
|
|
00db10 |
+ The GNU C Library is distributed in the hope that it will be useful,
|
|
|
00db10 |
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
|
00db10 |
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
|
00db10 |
+ Lesser General Public License for more details.
|
|
|
00db10 |
+
|
|
|
00db10 |
+ You should have received a copy of the GNU Lesser General Public
|
|
|
00db10 |
+ License along with the GNU C Library; if not, see
|
|
|
00db10 |
+ <http://www.gnu.org/licenses/>. */
|
|
|
00db10 |
+
|
|
|
00db10 |
+#include <ldsodefs.h>
|
|
|
00db10 |
+
|
|
|
00db10 |
+/* If the Prefer_MAP_32BIT_EXEC bit is set, try to map executable pages
|
|
|
00db10 |
+ with MAP_32BIT first. */
|
|
|
00db10 |
+#define MMAP_PREPARE(addr, len, prot, flags, fd, offset) \
|
|
|
00db10 |
+ if ((addr) == NULL \
|
|
|
00db10 |
+ && ((prot) & PROT_EXEC) != 0 \
|
|
|
00db10 |
+ && HAS_ARCH_FEATURE (Prefer_MAP_32BIT_EXEC)) \
|
|
|
00db10 |
+ { \
|
|
|
00db10 |
+ __ptr_t ret = (__ptr_t) INLINE_SYSCALL (mmap, 6, (addr), (len), \
|
|
|
00db10 |
+ (prot), \
|
|
|
00db10 |
+ (flags) | MAP_32BIT, \
|
|
|
00db10 |
+ (fd), (offset)); \
|
|
|
00db10 |
+ if (ret != MAP_FAILED) \
|
|
|
00db10 |
+ return ret; \
|
|
|
00db10 |
+ }
|
|
|
00db10 |
+
|
|
|
00db10 |
+#include <sysdeps/unix/sysv/linux/wordsize-64/mmap.c>
|
|
|
00db10 |
Index: glibc-2.17-c758a686/sysdeps/x86/cpu-features.h
|
|
|
00db10 |
===================================================================
|
|
|
00db10 |
--- glibc-2.17-c758a686.orig/sysdeps/x86/cpu-features.h
|
|
|
00db10 |
+++ glibc-2.17-c758a686/sysdeps/x86/cpu-features.h
|
|
|
00db10 |
@@ -32,6 +32,7 @@
|
|
|
00db10 |
#define bit_AVX_Fast_Unaligned_Load (1 << 11)
|
|
|
00db10 |
#define bit_AVX512F_Usable (1 << 12)
|
|
|
00db10 |
#define bit_AVX512DQ_Usable (1 << 13)
|
|
|
00db10 |
+#define bit_Prefer_MAP_32BIT_EXEC (1 << 16)
|
|
|
00db10 |
|
|
|
00db10 |
/* CPUID Feature flags. */
|
|
|
00db10 |
|
|
|
00db10 |
@@ -91,6 +92,7 @@
|
|
|
00db10 |
# define index_AVX_Fast_Unaligned_Load FEATURE_INDEX_1*FEATURE_SIZE
|
|
|
00db10 |
# define index_AVX512F_Usable FEATURE_INDEX_1*FEATURE_SIZE
|
|
|
00db10 |
# define index_AVX512DQ_Usable FEATURE_INDEX_1*FEATURE_SIZE
|
|
|
00db10 |
+# define index_Prefer_MAP_32BIT_EXEC FEATURE_INDEX_1*FEATURE_SIZE
|
|
|
00db10 |
|
|
|
00db10 |
# if defined (_LIBC) && !IS_IN (nonlib)
|
|
|
00db10 |
# ifdef __x86_64__
|
|
|
00db10 |
@@ -267,6 +269,7 @@ extern const struct cpu_features *__get_
|
|
|
00db10 |
# define index_AVX_Fast_Unaligned_Load FEATURE_INDEX_1
|
|
|
00db10 |
# define index_AVX512F_Usable FEATURE_INDEX_1
|
|
|
00db10 |
# define index_AVX512DQ_Usable FEATURE_INDEX_1
|
|
|
00db10 |
+# define index_Prefer_MAP_32BIT_EXEC FEATURE_INDEX_1
|
|
|
00db10 |
|
|
|
00db10 |
#endif /* !__ASSEMBLER__ */
|
|
|
00db10 |
|