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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 /ChangeLog | |
| parent | 2f44ee08dbf51d39ef5692699cc35f93faf64db1 (diff) | |
| download | glibc-7cbeabac0fb28e24c99aaa5085e613ea543a2346.zip glibc-7cbeabac0fb28e24c99aaa5085e613ea543a2346.tar.gz glibc-7cbeabac0fb28e24c99aaa5085e613ea543a2346.tar.bz2 | |
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 'ChangeLog')
| -rw-r--r-- | ChangeLog | 16 |
1 files changed, 16 insertions, 0 deletions
@@ -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] |