The use of 64-bit math on i386 causes build failures:
vdso_standalone_test_x86.c:(.text+0x101): undefined reference to `__umoddi3'
vdso_standalone_test_x86.c:(.text+0x12d): undefined reference to `__udivdi3'

Commit adb19fb6 (Documentation: add makefiles for more targets) is
now building this by default, so it's failing the kernel build entirely.

Switching the declaration from uint64_t to time_t does the right thing
and handles the x32 case automatically.
Signed-off-by: NJeff Mahoney <jeffm@suse.com>
Acked-by: NPeter Foley <pefoley2@pefoley.com>
Signed-off-by: NJonathan Corbet <corbet@lwn.net>

This adds a new vdso_test.c that's written entirely in C.  It also
makes all of the vDSO examples work on 32-bit x86.

Cc: Stefani Seibold <stefani@seibold.net>
Signed-off-by: NAndy Lutomirski <luto@amacapital.net>
Link: http://lkml.kernel.org/r/62b701fc44b79f118ac2b2d64d19965fc5c291fb.1402620737.git.luto@amacapital.netSigned-off-by: NH. Peter Anvin <hpa@zytor.com>

This thing is hopelessly x86_64-specific: it's an example of how to
access the vDSO without any runtime support at all.
Signed-off-by: NAndy Lutomirski <luto@amacapital.net>
Link: http://lkml.kernel.org/r/3efc170e0e166e15f0150c9fdb37d52488b9c0a4.1402620737.git.luto@amacapital.netSigned-off-by: NH. Peter Anvin <hpa@zytor.com>

It turns out that parsing the vDSO is nontrivial if you don't already
have an ELF dynamic loader around.  So document it in Documentation/ABI
and add a reference CC0-licenced parser.

This code is dedicated to Go issue 1933:
http://code.google.com/p/go/issues/detail?id=1933Signed-off-by: NAndy Lutomirski <luto@mit.edu>
Link: http://lkml.kernel.org/r/a315a9514cd71bcf29436cc31e35aada21a5ff21.1310563276.git.luto@mit.eduSigned-off-by: NH. Peter Anvin <hpa@linux.intel.com>