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| author | Adhemerval Zanella <adhemerval.zanella@linaro.com> | 2015-04-23 09:17:42 -0300 |
|---|---|---|
| committer | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2015-06-09 18:10:19 -0300 |
| commit | 7cbeabac0fb28e24c99aaa5085e613ea543a2346 (patch) | |
| tree | d51c207e3179fc7c1f03f53c3361224585429e8c /sysdeps/unix/sysv/linux/x86_64/gettimeofday.c | |
| parent | 2f44ee08dbf51d39ef5692699cc35f93faf64db1 (diff) | |
| download | glibc-7cbeabac0fb28e24c99aaa5085e613ea543a2346.tar.gz | |
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
Diffstat (limited to 'sysdeps/unix/sysv/linux/x86_64/gettimeofday.c')
| -rw-r--r-- | sysdeps/unix/sysv/linux/x86_64/gettimeofday.c | 26 |
1 files changed, 0 insertions, 26 deletions
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 daa14defb0..0000000000 --- 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> |