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authorAdhemerval Zanella <adhemerval.zanella@linaro.com>2015-04-23 09:17:42 -0300
committerAdhemerval Zanella <adhemerval.zanella@linaro.org>2015-06-09 18:10:19 -0300
commit7cbeabac0fb28e24c99aaa5085e613ea543a2346 (patch)
treed51c207e3179fc7c1f03f53c3361224585429e8c
parent2f44ee08dbf51d39ef5692699cc35f93faf64db1 (diff)
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x86: Remove vsyscall usage
This patch removes the vsyscall usage for x86_64 port. As indicated by kernel code comments [1], vsyscalls are a legacy ABI and its concept is problematic: - It interferes with ASLR. - It's awkward to write code that lives in kernel addresses but is callable by userspace at fixed addresses. - The whole concept is impossible for 32-bit compat userspace. - UML cannot easily virtualize a vsyscall. The VDSO is a better approach for such functionality. Tested on i686, x86_64, and x32. * sysdeps/unix/sysv/linux/i386/gettimeofday.c (__gettimeofday_syscall): Remove vsyscall fallback. * sysdeps/unix/sysv/linux/i386/time.c (__time_syscall): Likewise. * sysdeps/unix/sysv/linux/x86/gettimeofday.c (__gettimeofday_syscall): Add syscall fallback function. (gettimeofday_ifunc): Use __gettimeofday_syscall as fallback mechanism if vDSO is not present. * sysdeps/unix/sysv/linux/x86/time.c (__time_syscall): Add syscall fallback function. (time_ifunc): Use __time_syscall as fallback mechanism if vDSO is not present. * sysdeps/unix/sysv/linux/x86_64/gettimeofday.c: Remove file. * sysdeps/unix/sysv/linux/x86_64/time.c: Likewise. [1] arch/x86/kernel/vsyscall_64.c
-rw-r--r--ChangeLog16
-rw-r--r--sysdeps/unix/sysv/linux/i386/gettimeofday.c10
-rw-r--r--sysdeps/unix/sysv/linux/i386/time.c11
-rw-r--r--sysdeps/unix/sysv/linux/x86/gettimeofday.c11
-rw-r--r--sysdeps/unix/sysv/linux/x86/time.c12
-rw-r--r--sysdeps/unix/sysv/linux/x86_64/gettimeofday.c26
-rw-r--r--sysdeps/unix/sysv/linux/x86_64/time.c24
7 files changed, 36 insertions, 74 deletions
diff --git a/ChangeLog b/ChangeLog
index 2501f45..5f745e7 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,19 @@
+2015-06-09 Adhemerval Zanella <adhemerval.zanella@linaro.org>
+
+ * sysdeps/unix/sysv/linux/i386/gettimeofday.c
+ (__gettimeofday_syscall): Remove vsyscall fallback.
+ * sysdeps/unix/sysv/linux/i386/time.c (__time_syscall): Likewise.
+ * sysdeps/unix/sysv/linux/x86/gettimeofday.c (__gettimeofday_syscall):
+ Add syscall fallback function.
+ (gettimeofday_ifunc): Use __gettimeofday_syscall as fallback mechanism
+ if vDSO is not present.
+ * sysdeps/unix/sysv/linux/x86/time.c (__time_syscall): Add syscall
+ fallback function.
+ (time_ifunc): Use __time_syscall as fallback mechanism if vDSO is not
+ present.
+ * sysdeps/unix/sysv/linux/x86_64/gettimeofday.c: Remove file.
+ * sysdeps/unix/sysv/linux/x86_64/time.c: Likewise.
+
2015-06-09 Joseph Myers <joseph@codesourcery.com>
[BZ #18497]
diff --git a/sysdeps/unix/sysv/linux/i386/gettimeofday.c b/sysdeps/unix/sysv/linux/i386/gettimeofday.c
index 3e00eb4..fdb0fab 100644
--- a/sysdeps/unix/sysv/linux/i386/gettimeofday.c
+++ b/sysdeps/unix/sysv/linux/i386/gettimeofday.c
@@ -20,16 +20,6 @@
#ifdef SHARED
-# include <dl-vdso.h>
-# include <errno.h>
-
-/* If the vDSO is not available we fall back on the syscall. */
-static int
-__gettimeofday_syscall (struct timeval *tv, struct timezone *tz)
-{
- return INLINE_SYSCALL (gettimeofday, 2, tv, tz);
-}
-# define GETTIMEOFAY_FALLBACK (void*) (&__gettimeofday_syscall)
# undef libc_ifunc_hidden_def
# define libc_ifunc_hidden_def(name) \
libc_ifunc_hidden_def1 (__GI_##name, __gettimeofday_syscall)
diff --git a/sysdeps/unix/sysv/linux/i386/time.c b/sysdeps/unix/sysv/linux/i386/time.c
index e8a4e59..66b9a6c 100644
--- a/sysdeps/unix/sysv/linux/i386/time.c
+++ b/sysdeps/unix/sysv/linux/i386/time.c
@@ -18,17 +18,6 @@
#ifdef SHARED
-# include <dl-vdso.h>
-# include <errno.h>
-
-/* If the vDSO is not available we fall back on the old vsyscall. */
-static time_t
-__time_syscall (time_t *t)
-{
- INTERNAL_SYSCALL_DECL (err);
- return INTERNAL_SYSCALL (time, err, 1, t);
-}
-# define TIME_FALLBACK (void*) &__time_syscall
# undef libc_ifunc_hidden_def
# define libc_ifunc_hidden_def(name) \
libc_ifunc_hidden_def1 (__GI_##name, __time_syscall)
diff --git a/sysdeps/unix/sysv/linux/x86/gettimeofday.c b/sysdeps/unix/sysv/linux/x86/gettimeofday.c
index c820fd7..440cb02 100644
--- a/sysdeps/unix/sysv/linux/x86/gettimeofday.c
+++ b/sysdeps/unix/sysv/linux/x86/gettimeofday.c
@@ -21,6 +21,13 @@
#ifdef SHARED
# include <dl-vdso.h>
+# include <errno.h>
+
+static int
+__gettimeofday_syscall (struct timeval *tv, struct timezone *tz)
+{
+ return INLINE_SYSCALL (gettimeofday, 2, tv, tz);
+}
void *gettimeofday_ifunc (void) __asm__ ("__gettimeofday");
@@ -29,9 +36,9 @@ gettimeofday_ifunc (void)
{
PREPARE_VERSION_KNOWN (linux26, LINUX_2_6);
- /* If the vDSO is not available we fall back on the old vsyscall. */
+ /* If the vDSO is not available we fall back to syscall. */
return (_dl_vdso_vsym ("__vdso_gettimeofday", &linux26)
- ?: GETTIMEOFAY_FALLBACK);
+ ?: (void*) (&__gettimeofday_syscall));
}
asm (".type __gettimeofday, %gnu_indirect_function");
diff --git a/sysdeps/unix/sysv/linux/x86/time.c b/sysdeps/unix/sysv/linux/x86/time.c
index 1ab9248..ebf092a 100644
--- a/sysdeps/unix/sysv/linux/x86/time.c
+++ b/sysdeps/unix/sysv/linux/x86/time.c
@@ -21,6 +21,14 @@
#ifdef SHARED
#include <dl-vdso.h>
+#include <errno.h>
+
+static time_t
+__time_syscall (time_t *t)
+{
+ INTERNAL_SYSCALL_DECL (err);
+ return INTERNAL_SYSCALL (time, err, 1, t);
+}
void *time_ifunc (void) __asm__ ("time");
@@ -29,7 +37,9 @@ time_ifunc (void)
{
PREPARE_VERSION_KNOWN (linux26, LINUX_2_6);
- return _dl_vdso_vsym ("__vdso_time", &linux26) ?: TIME_FALLBACK;
+/* If the vDSO is not available we fall back on the syscall. */
+ return _dl_vdso_vsym ("__vdso_time", &linux26)
+ ?: (void*) &__time_syscall;
}
asm (".type time, %gnu_indirect_function");
diff --git a/sysdeps/unix/sysv/linux/x86_64/gettimeofday.c b/sysdeps/unix/sysv/linux/x86_64/gettimeofday.c
deleted file mode 100644
index daa14de..0000000
--- a/sysdeps/unix/sysv/linux/x86_64/gettimeofday.c
+++ /dev/null
@@ -1,26 +0,0 @@
-/* Copyright (C) 2002-2015 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 <sys/time.h>
-
-#ifdef SHARED
-/* If the vDSO is not available we fall back on the old vsyscall. */
-# define VSYSCALL_ADDR_vgettimeofday 0xffffffffff600000ul
-# define GETTIMEOFAY_FALLBACK (void*)VSYSCALL_ADDR_vgettimeofday
-#endif
-
-#include <sysdeps/unix/sysv/linux/x86/gettimeofday.c>
diff --git a/sysdeps/unix/sysv/linux/x86_64/time.c b/sysdeps/unix/sysv/linux/x86_64/time.c
deleted file mode 100644
index 6ceb819..0000000
--- a/sysdeps/unix/sysv/linux/x86_64/time.c
+++ /dev/null
@@ -1,24 +0,0 @@
-/* Copyright (C) 2001-2015 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/>. */
-
-#ifdef SHARED
-/* If the vDSO is not available we fall back on the old vsyscall. */
-#define VSYSCALL_ADDR_vtime 0xffffffffff600400
-#define TIME_FALLBACK (void*)VSYSCALL_ADDR_vtime
-#endif
-
-#include <sysdeps/unix/sysv/linux/x86/time.c>