[Bug libc/13425] New: Remove x86_64 Linux vsyscall page support

[Bug libc/13425] New: Remove x86_64 Linux vsyscall page support

[luto at mit dot edu]

http://sourceware.org/bugzilla/show_bug.cgi?id=13425

             Bug #: 13425
           Summary: Remove x86_64 Linux vsyscall page support
           Product: glibc
           Version: 2.14
            Status: NEW
          Severity: normal
          Priority: P2
         Component: libc
        AssignedTo: drepper.fsp@gmail.com
        ReportedBy: luto@mit.edu
    Classification: Unclassified


As of Linux 3.1, the vsyscall entry points (0xffffffffff600x00) are often
slower and never faster than real syscalls.  They are also somewhat fragile in
that they can confuse various binary tracing systems (e.g. the Chromium
sandbox) and they cause some problems with UML.

It would be nice to support the vdso in static binaries, but, failing that,
glibc should just stop using the vsyscall page.

(Note: for getcpu on older kernels without a real sys_getcpu syscall, the
vsyscall page or vdso support might be mandatory.  But the syscall should IMO
be preferred over the vsyscall entry.)

If this change is made, then vsyscall=none has a good chance of working :)

This is a continuation of bug 12813.

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[Bug libc/13425] Remove x86_64 Linux vsyscall page support

[aj at suse dot de]

http://sourceware.org/bugzilla/show_bug.cgi?id=13425

Andreas Jaeger <aj at suse dot de> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |aj at suse dot de

--- Comment #1 from Andreas Jaeger <aj at suse dot de> 2011-11-22 08:17:27 UTC ---
Andy,did you check the changes done in the glibc head branch?

Like the following

2011-09-06  Ulrich Drepper  <drepper@gmail.com>

        * sysdeps/unix/sysv/linux/x86_64/clock_gettime.c: New file.
        * sysdeps/unix/sysv/linux/clock_gettime.c (SYSCALL_GETTIME): Allow
        already be defined.  Change to take two parameters and don't assign
        result to variable.  Adjust all users.
        Define INTERNAL_GETTIME if not already defined.
        Use INTERNAL_GETTIME instead of INTERNAL_VSYSCALL got clock_gettime
        call.
        * sysdeps/unix/sysv/linux/x86_64/sysdep.h: Don't define
        HAVE_CLOCK_GETTIME_VSYSCALL.
        * sysdeps/unix/clock_gettime.c: Adjust use of SYSDEP_GETTIME_CPU.

        * sysdeps/unix/sysv/linux/getsysstats.c (__get_nprocs): Don't use
        gettimeofday vsyscall, just use time.

What is missing from current head?

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[Bug libc/13425] Remove x86_64 Linux vsyscall page support

[luto at mit dot edu]

http://sourceware.org/bugzilla/show_bug.cgi?id=13425

Andy Lutomirski <luto at mit dot edu> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |INVALID

--- Comment #2 from Andy Lutomirski <luto at mit dot edu> 2011-11-22 15:41:25 UTC ---
That should do it.  I thought I'd checked the git history, but I obviously did
a bad job.

Sorry for the noise.  I'll reopen if anything seems broken.

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[Bug libc/13425] Remove x86_64 Linux vsyscall page support

[fweimer at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=13425

Florian Weimer <fweimer at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
              Flags|                            |security-

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