S390: Add support for vdso getcpu symbol.

[Stefan Liebler]

Hi,

This patch adds support for symbol __kernel_getcpu in vDSO,
which is available with kernel 4.5.
Now sched_getcpu is using this symbol if available in mapped vDSO
by defining macro HAVE_GETCPU_VSYSCALL. If not available at runtime,
the former syscall is used.

Bye
Stefan

ChangeLog:

	* sysdeps/unix/sysv/linux/s390/init-first.c:
	Add VDSO_SYMBOL(getcpu).
	(_libc_vdso_platform_setup): Initialize VDSO_SYMBOL(getcpu).
	* sysdeps/unix/sysv/linux/s390/libc-vdso.h:
	Add VDSO_SYMBOL(getcpu).
	* sysdeps/unix/sysv/linux/s390/s390-32/sysdep.h:
	New define HAVE_GETCPU_VSYSCALL.
	* sysdeps/unix/sysv/linux/s390/s390-64/sysdep.h: Likewise.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: 20160429_vdso_getcpu.patch
Type: text/x-patch
Size: 3273 bytes
Desc: not available
URL: <http://sourceware.org/pipermail/libc-alpha/attachments/20160429/046d7ee7/attachment.bin>